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Garnet type electrolyte “Li6.5La3Ta0.5Zr1.5O12” (LLZTO) was prepared by conventional solid-state reaction in alumina crucibles and excess lithium salt (from 0% to 50 mol%) was added into the starting materials to investigate the effects of excess lithium salt on the property of LLZTO. SEM, XRD and AC impedance were used to determine the microstructure, phase formation and Li-ion conductivity. Cubic garnet with a minor second phase LiAlO2 in the grain boundary was obtained for the pellets with excess lithium salt. As the amount of excess lithium salt increased, more Al element diffused from alumina crucibles to LLZTO pellets and reacted with excess lithium salt to form liquid Li2O–Al2O3 phase in the grain boundary, which accelerated the pellets' densification and reduced lithium loss at a high temperature. Ionic conductivity of LLZTO pellets increased with the amount of excess lithium salt added and leveled off at ∼4 × 10−4 S cm−1 when lithium salt exceeded 30 mol%. The performance of Li-air batteries with hybrid electrolytes, using homemade LLZTO thin pellets as solid electrolytes, was investigated. The LLZTO thin pellet with more excess lithium salt in starting material had a higher density and resulted in better cell performance. | battery |
Manganese, in the form of oxide, was recovered from spent alkaline and zinc–carbon batteries employing a biohydrometallurgy process, using a pilot plant consisting in: an air-lift bioreactor (containing an acid-reducing medium produced by an Acidithiobacillus thiooxidans bacteria immobilized on elemental sulfur); a leaching reactor (were battery powder is mixed with the acid-reducing medium) and a recovery reactor. Two different manganese oxides were recovered from the leachate liquor: one of them by electrolysis (EMO) and the other by a chemical precipitation with KMnO4 solution (CMO). The non-leached solid residue was also studied (RMO). The solids were compared with a MnO x synthesized in our laboratory. The characterization by XRD, FTIR and XPS reveal the presence of Mn2O3 in the EMO and the CMO samples, together with some Mn4+ cations. In the solid not extracted by acidic leaching (RMO) the main phase detected was Mn3O4. The catalytic performance of the oxides was studied in the complete oxidation of ethanol and heptane. Complete conversion of ethanol occurs at 200°C, while heptane requires more than 400°C. The CMO has the highest oxide selectivity to CO2. The results show that manganese oxides obtained using spent alkaline and zinc–carbon batteries as raw materials, have an interesting performance as catalysts for elimination of VOCs. | non-battery |
Due to its high specific surface area, good chemical stability and outstanding electrical properties, graphene, a class of two-dimensional allotrope of carbon-based materials, is one of ideal candidates for next generation energy conversion and storage devices. In this review, we will present an overview on electrochemical characteristics of graphene by summarizing the recent research trend on graphene for energy conversion and storage applications, such as fuel cells and supercapacitors, along with some discussions on future research directions. | battery |
The as-electrospun polymeric lithium titanate nanofibers are crystallized into Li4Ti5O12 nanofibers (denoted as LTO NFs) via post-annealing. The LTO NFs are coated with a carbon layer using a glucose polymer via hydrothermal synthesis. The GO layer electrostatically attracts to the positively charged LTO NFs, resulting in the uniform wrapping of individual LTO NFs without aggregation. The introduction of uniformly coated carbon and GO double layers led to an enhanced rate capability (110mAhg−1 at 20C) and over two orders of magnitude higher diffusion coefficient (DLi =∼1.04×10−11 cm2 s−1) of the tailored LTO NFs with carbon and GO network compared with those of the pristine LTO NFs. Extended testing for over 100 cycles demonstrates the cyclic stability and Coulombic efficiency of over 99% of this system. These results indicate that the interconnection and networks of LTO NFs through carbon coating and the individual GO wrapping, which facilitates the lithium ion and electron transportation, may show excellent electrochemical performance. | battery |
The objective of the study was to determine the prevalence and associated factors for temporomandibular disorders (TMD) in a university sample of Campeche, Mexico. A cross-sectional study was carried out in 506 subjects aged 14–25 years. The subjects were requested to answer questionnaires concerning sociodemographic variables, history of stress, lifestyle, and anxiety. The Research Diagnostic Criteria for TMD (RDC/TMD) was used as TMD diagnostic system by four examiners capacitated and standardized. Data were analyzed using binary logistic regression in STATA. The results showed that 46.1% of the subjects exhibited some grade of TMD. Logistic regression analysis with TMD as the dependent variable identified sex (women odds ratio [OR]=1.7), bruxism (OR=1.5), anxiety (OR=1.6), unilateral chewing (OR=1.5), and an interaction between number of tooth loss and stress as the most significant associated variables, thus (1) the effect of having high levels of stress in the group of subjects without tooth loss (OR=1.2; 95% confidence interval [CI]=0.7–1.8) and (2) the effect of having high levels of stress in the group of subjects with at least one tooth lost (OR=2.4; 95% CI=1.01–5.9). The variables associated with diagnosis of pain were principally psychosocial (stress and anxiety), whereas for the non-pain diagnosis group, the variables were clinical, such as bruxism, chewing site preference, and restorations in mouth. We found associations among variables that were similar to findings in other studies, such as bruxism, tooth loss, stress, and anxiety. The final model explains that the effect of stress on TMD depends of the tooth loss, controlling for sex, bruxism, unilateral chewing, and anxiety. Finally, it can be concluded that the variables associated with pain and non-pain diagnosis were of distinct nature.
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This paper analyzes the timing of a new technology's economic feasibility using a simple yet novel approach. While the conventional wisdom that costs fall as cumulative production increases does not enable us to analyze this timing, the proposed approach enables us to do so using existing technological trends in the components that form a new technology's system. For 3D television, although the concepts that form the basis of 3D television have been known for many years, improvements in specific components within two-dimensional (2D) televisions such as the liquid crystal display (LCD) are finally making 3D television economically feasible. More specifically, improvements in the frame-rates of 2D LCDs are making it economically feasible to introduce time sequential 3D, which requires special glasses. Similarly, increases in the number of pixels per area (resolution) will probably make auto-stereoscopic 3D LCDs economically feasible in the next five to ten years and thus eliminate the need for special glasses. | non-battery |
Deep vein thrombosis prevention efficacy using a new, miniature, mobile, battery-operated pneumatic system (continuous enhanced circulation therapy [CECT] system) combined with low-dose aspirin was compared to enoxaparin. One hundred twenty-one patients who underwent total hip or knee arthroplasty were prospectively randomized into 2 groups. The study group was treated by the CECT system starting immediately after the induction of anesthesia. Postoperatively, a daily 100-mg aspirin tablet was added. The control group received 40 mg of enoxaparin per day. Bilateral venography was performed at the fifth to eight postoperative day. In the CECT group, as compared to the enoxaparin group, there was a significantly lower overall rate of DVT and proximal DVT. Safety profiles were similar in both groups. The combination of the CECT device with low-dose aspirin is more effective than enoxaparin in preventing deep-vein thrombosis after lower limb arthroplasties. | non-battery |
EPA’s Endocrine Disruptor Screening Program Tier 1 battery consists of eleven assays intended to identify the potential of a chemical to interact with the estrogen, androgen, thyroid, or steroidogenesis systems. We have collected control data from a subset of test order recipients from the first round of screening. The analysis undertaken herein demonstrates that the EPA should review all testing methods prior to issuing further test orders. Given the frequency with which certain performance criteria were violated, a primary focus of that review should consider adjustments to these standards to better reflect biological variability. A second focus should be to provide detailed, assay-specific direction on when results should be discarded; no clear guidance exists on the degree to which assays need to be re-run for failing to meet performance criteria. A third focus should be to identify permissible differences in study design and execution that have a large influence on endpoint variance. Experimental guidelines could then be re-defined such that endpoint variances are reduced and performance criteria are violated less frequently. It must be emphasized that because we were restricted to a subset (approximately half) of the control data, our analyses serve only as examples to underscore the importance of a detailed, rigorous, and comprehensive evaluation of the performance of the battery. | non-battery |
Nano-sized Fe2O3-loaded carbon material was prepared by loading Fe2O3 on carbon using various carbonaceous materials. Carbonaceous materials strongly affected the electrochemical behavior of nano-sized Fe2O3-loaded carbon. In addition, the binder content also significantly affected the cycle performance of nano-sized Fe2O3-loaded carbon. The content of binder depended on the type of carbon used. In the optimal condition for binder content, nano-carbons such as acetylene black (AB), tubular carbon nanofibers (CNF), and platelet CNF provided larger capacities than graphite, and tubular CNF showed the greatest capacity after long-term cycling. | battery |
The structure-activity relationship between the ORR performance and the surface electronic structure of Pd is constructed and the ORR performance are rationally modified via the structural transition from disordered face centered cubic phase (fcc, D-PdFe/C) to ordered intermetallic tetragonal phase (fct, O-PdFe/C). When the small amount of Pt atoms decorated on O-PdFe/C surface forming O-PdFe@Pt/C core-shell structure, the sublayer of Pd and Fe atoms may cause the lattice contraction of surface Pt and then weak the bonding energy on O-PdFe@Pt/C catalyst relative to bulk Pt/C, which is further illustrated by density functional theory (DFT) calculation. The weakened oxygen affinity results in the enhancement of ORR performance on O-PdFe@Pt/C. For a practical application, the well-constructed O-PdFe@Pt/C exhibits higher voltage and peak power density than D-PdFe@Pt/C and Pt/C when applied as the air-breathing cathode material in Zn-air battery. | battery |
Bifunctional redox flow batteries (BRFB) possess functions of both electricity storage and electrochemical preparation, having the potential for increasing the electrical energy utilization. A V(III)/V(II)–glyoxal(O2) system has been developed. Separators of the BRFB play a key role in BRFB performance. A Nafion solution was sprayed on a gas diffusion layer (GDL) at the Nafion loading of 2mgcm−2, and the GDL was then hot-pressed onto a Nafion115 cation exchange membrane, obtaining a modified separator. This separator not only prevents the crossover of vanadium but also has favorable conductivity, obtaining optimal charge and organic electro-synthesis performance of the BRFB. The effects of the concentrations of glyoxal and HCl on the performance of BRFB were also investigated. It is shown that the optimal concentration of glyoxal and HCl should be 1.2 and 3M, respectively. As a result, the current efficiency of organic electro-synthesis is further increased. An acceptable discharge performance is achieved for a period exceeding 20h at the current density of 20mAcm−2. The average discharge voltage of 0.73V and the coulombic efficiency of 66% are obtained. It is demonstrated that the principle of the BRFB is feasible. However, further experiments are needed to improve the performance. | battery |
Cu–MOF was obtained by a facile aqueous room temperature synthesis method, and Cu–C was prepared by using Cu–MOF as a sacrificial template. The ultrafine SnOx nanoparticles were loaded onto Cu–C by a pyrolysis process to form SnOx/Cu–C. Cyclic voltammetry and galvanostatic charge/discharge were employed to examine the electrochemical properties of the as-synthesized composite. Benefiting from the excellent conductivity of Cu, the ultra-fine size of nanoparticles, the unique structure derived from MOF and the synergistic effect between SnOX and Cu–C, SnOX/Cu–C electrode exhibited an exceptional electrochemical property. A high charge specific capacity of 649 mA h g−1 can be reached even at a current density of 2000 mAg−1. The reversible capacity is maintained at 668 mA h g−1 at 1000 mA g−1 after 300 cycles. The results indicate that the material may be considered as a promising anode candidate for lithium-ion batteries. | battery |
Graphene nanosheet/carbon nanotube/polyaniline (GNS/CNT/PANI) composite is synthesized via in situ polymerization. GNS/CNT/PANI composite exhibits the specific capacitance of 1035Fg−1 (1mVs−1) in 6M of KOH, which is a little lower than GNS/PANI composite (1046Fg−1), but much higher than pure PANI (115Fg−1) and CNT/PANI composite (780Fg−1). Though a small amount of CNTs (1wt.%) is added into GNS, the cycle stability of GNS/CNT/PANI composite is greatly improved due to the maintenance of highly conductive path as well as mechanical strength of the electrode during doping/dedoping processes. After 1000 cycles, the capacitance decreases only 6% of initial capacitance compared to 52% and 67% for GNS/PANI and CNT/PANI composites. | battery |
We report single-crystalline TiO2 nanowires (TiO2-NWs) synthesized by hydrothermal process without any surfactant and template with enhanced lithium intercalation properties. The single-crystalline nature of rutile TiO2-NWs was clearly observed by field-emission transmission electron microscopy and fast Fourier transform pattern demonstrating that the nanowire growth is along the [001] direction. The single-crystalline rutile TiO2-NWs showed much higher charge capacity and excellent high-rate performance as compared to typical rutile TiO2 nanoparticles. The improved lithium-ion intercalation properties of TiO2-NWs may be attributed to relatively large specific surface area, short transport distance of 1-D nanostructure, and freedom for volume change accompanied by lithium-ion intercalation. | battery |
The limitations of two-dimensional electrodes can be overcome by using three-dimensional materials having sufficient porosity and active area while offering moderate mass transport rates and a relatively low pressure drop at controlled electrolyte flow rate. In concept, a wide variety of metal, ceramic and composite materials are possible but restrictions are imposed by the need to avoid materials degradation, while maintaining adequate electrical conductivity, sufficient robustness and the possibility of facile scale-up. Despite its fragility, one of the traditional electrode materials used as a porous, three-dimensional electrode is carbon foam, particularly in the 97% vol. porous form of reticulated vitreous carbon, RVC. A time-line indicates that the history of this material dates back over 50 years to the mid-1960s, when it was primarily used as an uncoated material in small-scale, laboratory electroanalysis. Surface modification and diverse coatings have considerably extended the use of RVC. Recent applications are found in sensors and monitors, electrosynthesis, environmental processing and energy conversion. This review highlights the fundamental structure and summarises the physicochemical properties of RVC. Fluid flow through various porosity grades of the material, their active electrochemical area and rates of mass transport are quantified. The diverse applications of RVC in energy conversion, environmental treatment and electrosynthesis are illustrated by selected examples from the authors’ laboratories and others over the last 30 years. Recent research on coated RVC, energy conversion environmental remediation and sensors is highlighted. Critical areas deserving further research and development are proposed. | battery |
The specific discharge capacity of γ-MnO2 was improved with chemical oxidation and vacuum-drying processes. The intergrowth structure and electrochemical performance were studied by X-ray diffraction and electrochemical measurements; the structure–electrochemical property relationships were clarified. Vacuum-dried γ-MnO2 showed structural changes with capacity fade as the temperature increased, while the chemically oxidized γ-MnO2 showed no structural change without any capacity fading. The latter material showed a first discharge capacity of 275mAhg−1, and a reversible capacity of 250mAhg−1 with two discharge plateaux after second cycle, which is the highest capacity among the γ-MnO2 prepared previously. | battery |
Solar-hydrogen generation represents a promising alternative to fossil fuels for the large-scale implementation of a clean-fuel transportation infrastructure. A significant amount of research resources has been allocated to the development of photoelectrochemical components (i.e. photovoltaic and water splitting catalysts) that are able to spontaneously split water in the presence of solar irradiation, which has led to major advances in the solar-fuels field. At the same time, only limited attention has been given to understanding the key aspects that drive economically viable solar-fuel generators. This study presents a generalized approach to understand the economic factors behind the design of solar-hydrogen generators composed of photovoltaic components integrated with water electrolyzers. It evaluates the underpinning effects of the material selection for the light absorption and water splitting components on the cost of the generated fuel ($ per Kg of H2). The results presented in this work provide insights into important engineering aspects related to the sizing of devices and the use of light concentration components that, when optimized, can lead to costs below $2.90 per kilogram of hydrogen after compression and distribution. Most significantly, the analysis demonstrates that the cost of hydrogen is defined primarily by the light-absorbing component (up to 97% of the cost) while the material selection for the electrolysis components has, to a large extent, minor effects. The findings presented here can help direct research and development efforts towards the fabrication of deployable solar-hydrogen generators that are cost competitive with commercial energy sources.
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Electrocatalytic water-splitting is one of the most economical and clean way for high-purity hydrogen production utilizing renewable energy sources. Key issue to large-scale implementation of this technology is the lack of efficient electrocatalysts that can deliver large current density at low overpotential for oxygen and hydrogen evolution reactions (OER and HER). Herein, we report a strategy leveraging 3D MXene frame with high conductivity, highly hydrophilic properties and kinetics-favorable architecture as multi-functional structural scaffold for engineering water-splitting electrocatalysts yielding high current densities. The macroporous 3D MXene frame not only facilitates the mass/charge transport across the catalyst, but also accelerates the OER redox process of NiFe-LDHs and the Volmer step of HER by enhancing the water adsorption/activation on the catalyst. Commercially required high current density of 500 mA cm−2 can be achieved at low overpotentials for both OER (300 mV) and HER (205 mV) with good durability in 1.0 M KOH. Alkaline electrolyzer using this electrocatalytic electrode as both the anode and cathode exhibit low cell voltage for achieving high current density of 500 mA cm−2 with high Faradaic efficiency and excellent durability. Their performance outperforms the Pt/C–RuO2 couple and the state-of-the-art electrocatalysts for overall water-splitting in alkaline electrolyte. | battery |
Herein, a hierarchical calliandra-like Co3O4 is successfully synthesized via a simple carbon sphere and hydroxypropyl cellulose assisted hydrothermal process. X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) characteristics results indicate that the hierarchical Co3O4 spheres are 3–6 μm in diameter and belong to spinel structure. Each Co3O4 sphere is consisted of radially oriented nanocystals accumulated nanorods building blocks. The formation mechanism for this structure maybe ascribed to the collaboration effect of carbon sphere and hydroxypropyl cellulose, which act as hard template and dispersion stabilizer respectively. The calliandra-like Co3O4 particles exhibit satisfied electrochemical performance with high specific capacities and good rate capabilities, especially superior cycling stability when used as anode active materials in the lithium-ion batteries, which release an initial discharge capacity of 1139.42 mA h g−1 at 200 mA g−1, and maintain a reversible capacity of 734.64 mA h g−1 after 500 cycles. | battery |
Lithium–sulfur (Li–S) batteries have attracted much attention due to their ultrahigh theoretical specific capacity. However, serious capacity attenuation caused by shuttle effect still inhibits the performance improvement. Herein, a modified separator consists of the few-layer graphene as a highly conductive network and stable scaffold to support P-doped boron nitride (denoted as BN-P@GO) as the functional interlayer of Li–S batteries. The cell with the interlayer provides an initial discharge capacity as high as 1045.3 mAh g−1, and retains a high reversible capacity of 728.7 mAh g−1 at 1 C after 500 cycles with a capacity decay of 0.061% per cycle. Moreover, the rate capability is also superior to cells with BN@GO or BN-P interlayers, i.e. reversible capcity of 457.9 mAh g−1 even at 3 C. The excellent electrochemical performance is ascribed to the synergistic effect of physical barrier and chemical adsorption for dissolved polysulfides provided by the modified layer. Furhtermore, it also mitigates the polarization and promotes kinetic reactions of the cells. This work provides a concise and effective method for commercialization of lithium–sulfur batteries. | battery |
We derive and implement a battery control algorithm that can accommodate an arbitrary number of model parameters, with each model parameter having its own time-weighting factor, and we propose a method to determine optimal values for the time-weighting factors. Time-weighting factors are employed to give greater impact to recent data for the determination of a system’s state. We employ the (controls) methodology of weighted recursive least squares, and the time weighting corresponds to the exponential-forgetting formalism. The output from the adaptive algorithm is the battery state of charge (remaining energy), state of health (relative to the battery’s nominal performance), and predicted power capability. Results are presented for a high-power lithium ion battery.
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Unknown | non-battery |
Residual excessive sleepiness (ES) and impaired cognition can occur despite effective and regular nasal continuous positive airway pressure (nCPAP) therapy in some patients with obstructive sleep apnea (OSA). A pooled analysis of two 12-week, randomized, double-blind studies in nCPAP-adherent patients with ES associated with OSA evaluated the effect of armodafinil on wakefulness and cognition. Three hundred and ninety-one patients received armodafinil (150 or 250 mg) and 260 patients received placebo once daily for 12 weeks. Efficacy assessments included the Maintenance of Wakefulness Test (MWT), Cognitive Drug Research cognitive performance battery, Epworth Sleepiness Scale, and Brief Fatigue Inventory. Adverse events were monitored. Armodafinil increased mean MWT sleep latency from baseline to final visit by 2.0 min vs a decrease of 1.5 min with placebo (P < 0.0001). Compared with placebo, armodafinil significantly improved quality of episodic secondary memory (P < 0.05) and patients’ ability to engage in activities of daily living (P < 0.0001) and reduced fatigue (P < 0.01). The most common adverse events were headache, nausea, and insomnia. Armodafinil did not adversely affect desired nighttime sleep, and nCPAP use remained high (approximately 7 h/night). Adjunct treatment with armodafinil significantly improved wakefulness, long-term memory, and patients’ ability to engage in activities of daily living in nCPAP-adherent individuals with ES associated with OSA. Armodafinil also reduced patient-reported fatigue and was well tolerated.
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This paper presents ride comfort and driving stability performances of electronic control suspension (ECS) equipped with controllable electrorheological (ER) damper and appropriate control strategy. In order to achieve this goal, a cylindrical type ER damper which is applicable to Macpherson strut type suspension of a mid-sized passenger vehicle is designed and manufactured on the basis of the required damping force level of an existing passenger vehicle. After experimentally evaluating the field-dependent damping force and dynamic characteristics of the controllable ER damper, ECS consisting of sprung mass, spring, tire and controller is established in order to investigate the ride comfort and driving stability performances. On the basis of the governing equation of motion of the suspension system, five control strategies (soft, hard, comfort, sports and optimal mode) are formulated. The proposed control strategies are then experimentally realized with the quarter-vehicle ECS system. Control performances such as vertical acceleration of the car body and tire deflection are evaluated in both time and frequency domains under various road conditions. In addition, a comparative work is undertaken to investigate inherent control characteristics of each control strategy.
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The electrochemical reduction and oxidation of cyclohexanedione is evaluated for the first time as the negative electrode reaction in an organic redox flow battery. Electrochemical characterization indicates that the redox reaction of cyclohexanedione is a proton-coupled electron transfer process with quasi-reversible behavior in acidic media (pH<3). Among three isomeric compounds (1,2-, 1,3- and 1,4-cyclohexanedione), the reduction of 1,3-cyclohexanedione exhibits the most negative electrode potential (c.a. −0.6V vs. Ag|AgCl (c.a. −0.4V vs. NHE)) as well as the widest pH operating range (pH 1–5) for relatively reversible reactions. The resulting electrode potential is the most negative of those to have been reported in neutral/acidic electrolytes. 1,3-cyclohexanedione is subsequently used as the active species in the negative electrode of a parallel plate flow cell, which is charge-discharge cycled at 3.4mAcm−2 for 100 cycles, yielding half-cell coulombic efficiencies of c.a. 99%. The organic molecules derived from this group are observed to have high solubilities (>2M) and exhibit reduction process with up to 4 electrons transferred. | battery |
An amorphous silicon film with an average thickness of up to 2μm was deposited on copper foil by direct-circuit (dc) magnetron sputtering and coupled with commercial LiCoO2 cathode to fabricate cells. Their cycle performance and high rate capability at room temperature have been investigated. In the voltage range 2.5–3.9V at the current density of 0.2C (0.11mAcm−2), the lithiation and delithiation capacity of this cell was first increased to 0.55mAhcm−2 within 80 cycles and maintained stable during the following cycles. After 300 cycles its capacity still retained 0.54mAhcm−2. High-resolution transmission electron microscopy (HRTEM) and selected area electron diffraction (SAED) image indicated that the sputtered film could keep an amorphous structure although the volume expansion ratio during the lithiation and delithiation was still up to 300% after 300 cycles observed from scanning electron microscopy (SEM) image. This recovered amorphous structure was believed to be beneficial for the improvement of the cycle life of the cell. Rate performance showed that the cells had a promising high rate capability. At 30C, its lithiation/delithiation capacity remained 25% of that at 0.2C. | battery |
The size- and shape-dependency of the chemo-mechanical behavior of spherical and ellipsoidal nanoparticles in Li-ion battery electrodes are investigated by a stress-assisted diffusion model and 3D finite element simulations. The model features surface tension, a direct coupling between diffusion and elasticity, concentration-dependent diffusivity, and a Butler-Volmer relation for the description of electrochemical reactions that is modified to account for mechanical effects. Simulation results on spherical particles reveal that surface tension causes additional pressure fields in the particles, shifting the stress state towards the compressive regime. This provides mechanical stabilization, allowing, in principle, for higher charge/discharge rates. However, due to this pressure the attainable lithiation for a given potential difference is reduced during insertion, whereas a higher amount of ions is given off during extraction. Ellipsoidal particles with an aspect ratio deviating from that of a sphere with the same volume expose a larger surface area to the intercalation reactions. Consequently, they exhibit accelerated (dis)charge rates. However, due to the enhanced pressure in regions with high curvature, the accessible capacity of ellipsoidal particles is less than that of spherical particles. | battery |
In recent years, there has been much interest in the development of solid oxide fuel cell technology operating directly on hydrocarbon fuels. The development of a catalytic fuel processing system, which is integrated with the solid oxide fuel cell (SOFC) power source is outlined here. The catalytic device utilises a novel three-way catalytic system consisting of an in situ pre-reformer catalyst, the fuel cell anode catalyst and a platinum-based combustion catalyst. The three individual catalytic stages have been tested in a model catalytic microreactor. Both temperature-programmed and isothermal reaction techniques have been applied. Results from these experiments were used to design the demonstration SOFC unit. The apparatus used for catalytic characterisation can also perform in situ electrochemical measurements as described in previous papers [C.M. Finnerty, R.H. Cunningham, K. Kendall, R.M. Ormerod, Chem. Commun. (1998) 915–916; C.M. Finnerty, N.J. Coe, R.H. Cunningham, R.M. Ormerod, Catal. Today 46 (1998) 137–145]. This enabled the performance of the SOFC to be determined at a range of temperatures and reaction conditions, with current output of 290 mA cm−2 at 0.5 V, being recorded. Methane and butane have been evaluated as fuels. Thus, optimisation of the in situ partial oxidation pre-reforming catalyst was essential, with catalysts producing high H2/CO ratios at reaction temperatures between 873 K and 1173 K being chosen. These included Ru and Ni/Mo-based catalysts. Hydrocarbon fuels were directly injected into the catalytic SOFC system. Microreactor measurements revealed the reaction mechanisms as the fuel was transported through the three-catalyst device. The demonstration system showed that the fuel processing could be successfully integrated with the SOFC stack. | battery |
The commercialization of Lithium–sulfur (LiS) batteries is being hampered by the inherent insulation and volume expansion of sulfur, as well as by shuttle effect of polysulfides. To expand the LiS application, Co9S8@S nanotube composites were developed and fabricated via hydrothermal method combining with incorporating sulfur using melt-diffusion method. In comparison with pure sulfur cathode, the Co9S8@S nanotube composites cathode delivered excellent specific capacity, had remarkable rate performance and superior coulombic efficiency. The initial capacity of Co9S8@S nanotube composites cathode was 937mAh/g and stabled at 650mAh/g after 100cycles at 0.1C, much superior than pure S electrode. The improved electrochemical performance of Co9S8@S nanotube composites cathode was awarded to highly conductive and polar Co9S8 nanotubes. On the one hand, Co9S8 nanotubes help to form effective conductive networks which can improve the transport of electrons/lithium ion and overall electrical conductivity; on the other hand, polar Co9S8 nanotubes entrapped polysulfides through chemical adsorption to alleviate the shuttle effect. In addition, sulfur particles were well-distributed on the hollow Co9S8 nanotubes, which relieve the volume expansion of sulfur effectively. These synergistic effects were achieved by physical constraints and chemical effects of hollow Co9S8 nanotubes. | battery |
Several compounds have been employed as additives of the V(V) electrolyte for vanadium redox flow battery (VRB) to improve its stability and electrochemical activity. Stability of the V(V) electrolyte with and without additives was investigated with ex-situ heating/cooling treatment over a wide temperature range of −5°C to 60°C. It was observed that methyl orange (MO), Triton X-100 (OP), sodium ligninsulfonate (SL), sodium dodecyl sulfate (SDS) and polyvinyl alcohol (PVA) could significantly improve the stability of the V(V) electrolyte at a wide range of temperature. Their electrochemical behavior in the V(V) electrolyte were further studied by cyclic voltammetry (CV), steady state polarization and electrochemical impedance spectroscopy (EIS). The results showed that the electrochemical activity, including the reversibility of electrode reaction, the diffusivity and polarization resistance of V(V) species and the feasibility of charge transfer of V(V)/V(IV) for the V(V) electrolyte with these additives was all improved compared with the pristine solution. | battery |
Electric commercial delivery trucks have the potential to substantially reduce greenhouse gas emissions and pollution and lower per-mile operating and maintenance costs. However, the initial purchase cost of electric vehicles is significantly higher than that of a conventional diesel truck. In addition, electric vehicles have a limited range that may lead to the well known problem commonly known as “range anxiety” due to the lack of nearby recharging stations. From a purely economic perspective, there is a cost tradeoff between low operating and maintenance costs of electric vehicles and their high initial capital costs. In this paper, a deterministic integer programming model is utilized to analyze the competitiveness of commercial electric vehicles. Utilizing realistic assumptions and a wide range of scenarios regarding fleet utilization and fuel efficiency, this research finds breakeven points where electric vehicles become competitive. Results show that under moderate to high utilization levels, the electric vehicles can be competitive. | non-battery |
To increase energy density in lithium-ion batteries (LIBs), novel anode materials are considered based on conversion and alloying mechanisms as these typically possess far higher storage capacity than graphite, however, cyclability of these compounds is typically poor. To overcome these issues, ternary or ‘mixed’ compounds are considered. However, the degree of mixing is often overlooked. Here, Atomic layer deposition (ALD) is used to investigate the influence of the degree of mixing, composition and crystallinity of ZnO–SnO2 ternary materials as LIB anodes. Firstly, two different mixing nanostructures of thin-film ZnO–SnO2 electrodes are constructed: atomically intermixed films where the Zn, Sn and O are mixed at the atomic scale in a single amorphous layer, and nanolaminated films where the ZnO layer and SnO2 layers form a structure with well-defined interfaces. Secondly, by tuning the ratio of ZnO and SnO2, different compositions are obtained. Finally, when ZnO–SnO2 composite films are annealed post-deposition, these can be crystallized to form Zn2SnO4 films. The electrochemical performances of these different variations of ternary ZnO–SnO2 composites were investigated as anode materials in LIBs. This demonstrated the potential of ALD as a research tool in LIBs research and revealed the importance of atomic scale intermixing in these ternary oxides as anodes. | battery |
Kinta district, in Perak sate of Malaysia is one of the richest districts that rose from tin mining production and is located strategically in the middle of Perak. The physical evidence of this former tin mining landscape which surrounds Kinta offers a narrative about this past mining history. The glorious years of Kinta occurred during the ‘tin rush’ era between 1884 until 1895. The purpose of this paper is to investigate the mining heritage significance in Kinta district. A critical literature review and field surveys are used as the initial identification of significance places having regard to the remaining surviving evidence that can be promoted for conservation. | non-battery |
Nonstoichiometry and Na incorporation are designed to attain controllable impurity phases Li4P2O7 and Li3PO4 in LiFePO4. The effects of Li4P2O7 and Li3PO4 on structure and electrochemical performance have been investigated. Both Li4P2O7 and Li3PO4 impurities are observed in (Fe, P)-deficient LiFe0.9P0.95O4−δ . With Na+ incorporation, Li4P2O7 phase disappears while Li3PO4 content increases. Proved by X-ray photoelectron spectroscopy, nonstoichiometry and Na-incorporation do not change the chemical state of Fe(II). Our experiments indicate that Li4P2O7 and Li3PO4 show different effects on the electrochemical performance. Li4P2O7 leads to degradation of cyclability, whereas a small amount of Li3PO4 is beneficial for the improvement in capacity and rate capability. The 1% Na-doped LiFe0.9P0.95O4−δ composite exhibits the best electrochemical performance. We ascribe the improvement to the structural stabilization caused by the existence of Li3PO4. | battery |
As a part of a larger study of normal aging and Alzheimer’s disease (AD), which included patients with mild cognitive impairment (MCI), we investigated the response to median nerve stimulation in primary and secondary somatosensory areas. We hypothesized that the somatosensory response would be relatively spared given the reported late involvement of sensory areas in the progression of AD. We applied brief pulses of electric current to left and right median nerves to test the somatosensory response in normal elderly (NE), MCI, and AD. MEG responses were measured and were analyzed with a semi-automated source localization algorithm to characterize source locations and timecourses. We found an overall difference in the amplitude of the response of the primary somatosensory source (SI) based on diagnosis. Across the first three peaks of the SI response, the MCI patients exhibited a larger amplitude response than the NE and AD groups (P < 0.03). Additional relationships between neuropsychological measures and SI amplitude were also determined. There was no significant difference in amplitude for the contralateral secondary somatosensory source across diagnostic category. These results suggest that somatosensory cortex is affected early in the progression of AD and may have some consequence on behavioral and functional measures. | non-battery |
Anodal transcranial direct current stimulation (tDCS) of the prefrontal cortex has repeatedly been shown to improve working memory. As patients with attention deficit hyperactivity disorder (ADHD) are characterized by both underactivation of the prefrontal cortex and deficits in working memory that correlate with clinical symptoms, it is hypothesized that the modulation of prefrontal activity with tDCS in patients with ADHD increases performance in working memory and reduces symptoms of ADHD. To test this hypothesis, fifteen adolescents with ADHD (12–16 years old, three girls and 12 boys) were treated according to the randomized, double-blinded, sham-controlled, crossover design with either 1 mA anodal tDCS over the left dorsolateral prefrontal cortex or with the sham protocol 5 days each with a 2 weeks pause between these conditions. Anodal tDCS caused a significant reduction in clinical symptoms of inattention and impulsivity in adolescents with ADHD compared to sham stimulation. The clinical effects were supported by a significant reduction in inattention and hyperactivity in a standardized working memory test (QbTest). The described effects were more pronounced 7 days after the end of stimulation, a fact which emphasizes the long-lasting clinical and neuropsychological changes after tDCS. This study provides the first evidence that tDCS may reduce symptoms of ADHD and improve neuropsychological functioning in adolescents and points on the potential of tDCS as a form of treatment for ADHD. | non-battery |
Supercapacitors can deliver high electrical power because of fast ion adsorption/desorption on the surface or surface redox reactions, which, in turn, restrict their energy density. To break surface-storage ceiling and further improve the energy density, here, we develop a cost-effective, layered material made of amorphous metal-organic nanosheets, Ni-p-phenylenediamine (Ni-pPD), with a large intersheet spacing of 1.6 nm for its robust and highly reversible intercalation reaction with tetraethylammonium cations. When coupled with activated carbon cathode, the 230 μm-thick Ni-pPD anode shows a high gravimetric capacitance (259 F g−1) and a high areal capacitance (2.9 F cm−2) at 2 A g−1 within a wide potential window of 2.85 V in the organic electrolyte of tetraethylammonium tetrafluoroborate/acetonitrile. In-situ electrochemical atomic force microscopy reveals that high kinetics at high potentials are attributed to the increased intersheet spacing under large polarization, demonstrating structural advantages of this novel material and its great potential for real-world applications. | battery |
Reaction of TiCl4 with L–L [L–L = MeE(CH2)nEMe; E = S or Se, n = 2 or 3, PhE(CH2)2EPh or o-C6H4(EMe)2] in anhydrous n-hexane solution under an N2 atmosphere results in the rapid formation of [TiCl4(L–L)] as yellow, orange or red solids. Analogous bromo and iodo species, [TiX4(L–L)] [X = Br; L–L = MeE(CH2)nEMe or o-C6H4(EMe)2; X = I; L–L = MeSe(CH2)2SeMe or o-C6H4(SeMe)2], were obtained as intense orange or red coloured solids by treatment of TiX4 with L–L in CH2Cl2 solution. Crystallographic studies on [TiCl4{MeS(CH2)2SMe}], [TiCl4{MeS(CH2)3SMe}], [TiCl4{MeSe(CH2)3SeMe}] and [TiCl4{o-C6H4(SeMe)2}] reveal a distorted octahedral arrangement with the coordinated group 16 donor ligand adopting the DL form in the first three cases and the meso form in the fourth example. These studies also reveal a trans influence series of Cl > S ≈ Se on Ti(IV). Solution NMR studies show that the chloro-compounds undergo rapid pyramidal inversion at ambient temperature, while the bromo and iodo species also undergo rapid ligand dissociation/chelate ring-opening. At low temperature these processes are slowed significantly, such that in most of the chloro and bromo species it is possible to identify both the meso and DL invertomers, although ligand exchange is still rapid at 200 K for the iodo species. The potential of these compounds as sources of titanium sulfide or titanium selenide phases via controlled decomposition is also discussed briefly. Finally, the dinuclear species, [Cl3Ti{MeS(CH2)2SMe}]2(μ-O), formed by partial hydrolysis of [TiCl4{MeS(CH2)2SMe}], has also been identified crystallographically.
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A novel free-standing type cathode of rechargeable Li–O2 battery composed of only Co3O4 catalyst and Ni foam current collector was designed and realized by a simple chemical deposition reaction. The carbon and binder are no longer necessary for the air electrode. The new air electrode was found to yield obviously higher specific capacity and improved cycle efficiency than the conventional carbon-supported one with almost the highest discharge voltage (2.95 V), the lowest charge voltage (3.44 V), the highest specific capacity (4000 mAh g−1cathode) and the minimum capacity fading among the Li–O2 batteries reported to date. During its discharge process, the discharge products would deposit at the surface and in the pores of the free-standing catalysts. The improved performance was attributed to the abundant available catalytic sites of the particularly structured air electrode, the intimate contact of the discharge product with the catalyst, the effective suppression of the volume expansion in the electrode during subsequent deposition/decomposition of the discharge products, the good adhesion of the catalyst to the current collector, and the open pore system for unrestricted access of the reactant molecules to and from active sites of the catalysts. Furthermore, EIS study pointed out the intrinsic distinction resulting in the different performance between the new electrode and the conventional carbon-supported electrode. The new free-standing type electrode represents a critical step toward developing high-performance Li–O2 batteries.
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To further improve the electrochemical performance of MXene materials, MXene(Ti3C2Tx)/α-Fe2O3 nanocomposites are fabricated by a self-assembly method via electrostatic attraction between negatively charged Ti3C2Tx MXenesand positively charged cocoa-like α-Fe2O3 nanoparticles at room temperature. As a negative electrode material, the resulting nanocomposites show excellent electrochemical performance, including a wide operating potential of 1.2 V (−1.2–0 V), a high specific capacitance of 405.4 F g−1 at the current density of 2 A g−1 and a specific capacitance of 197.6 F g−1 even at the current density of 20 A g−1 in 5 M LiCl. In addition, the nanocomposites possess a high cycling stability with 97.7% capacitance retention of the initial capacitance after 2000 cycles. The impressive results indicate that the prepared MXene(Ti3C2Tx)/α-Fe2O3 nanocomposites is a promising negative electrode material for supercapacitor. The self-assemble of MXenes and metal oxides will provide more opportunities for their application in energy storage. | battery |
In this study, a hybrid energy storage system (HESS), which combines battery for long-term energy management and supercapacitor for fast dynamic power regulation, is proposed for remote area renewable energy power supply systems. The operation of a passive connected HESS was examined via both theoretical analysis and numerical simulation using Matlab/Simulink. An electric inductor was further introduced to improve the performance of the HESS. An experimental test bench was developed to validate the simulation results. It was demonstrated that the HESS can stabilize energy provision, not only for the intermittent renewable energy (RE), but also for fluctuating load applications. | battery |
Mesoporous NiCo2O4 nanoneedles were directly grown on three dimensional (3D) graphene-nickel foam which was prepared by chemical vapor deposition, labeled as NCO/GNF. The structure and morphology of NCO/GNF were investigated by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, element mapping and Raman spectroscopy. The NCO/GNF was employed as electrodes for supercapacitor and methanol electro-oxidation. When used for supercapacitor, the NiCo2O4 nanoneedles exhibit hi exhibit high specific capacitance (1588Fg−1 at 1Ag−1), high power density and energy density (33.88Whkg−1 at 5kWkg−1) as well as long cycling stability. In methanol electro-oxidation, the NiCo2O4 nanoneedles deliver high electro-oxidation activity (93.3Ag−1 at 0.65V) and electro-oxidation stability. The good electrochemical performance of NiCo2O4 nanoneedles is attributed to the 3D structure with large specific area, high conductivity and fast ions/electrons transport. | battery |
Fish mortality and hypoxic events occur in many coastal and inland systems and may result from natural or anthropogenically mediated processes. The effects of consequent changes in water biogeochemistry have been investigated for communities of benthic invertebrates and pelagic metazoans. The responses of micro-plankton assemblages, however, have remained largely unstudied. The northern basin of King Harbor, a small embayment within Santa Monica Bay, CA, USA, suffered a massive fish kill in March 2011 as a consequence of acute hypoxia. Dissolved oxygen concentrations < 0.1 ml l−1 were measured in the northern basin of the harbor for several days following the mortality event, and a strong spatial gradient of oxygen was observed from the northern basin to waters outside the harbor. The microplankton community within King Harbor differed significantly from a diatom-dominated community present in neighboring Santa Monica Bay. The latter region appeared unaffected by physicochemical changes, induced by the fish kill, that were observed within the harbor. A trophic shift was observed throughout King Harbor from a photoautotrophic-dominated assemblage to one of heterotrophic forms, with relative abundances of bacterivorous ciliates increasing by more than 80 % in the most impacted part of the harbor. Significant changes in community structure were observed together with dramatically reduced photosynthetic yield of the remaining phytoplankton, indicating severe physiological stress during the extreme hypoxia. | non-battery |
Recycling of plastics is a big issue in terms of environmental sustainability and of waste management. The development of proper technologies for plastic recycling is recognised as a priority. To achieve this aim, the technologies applied in mineral processing can be adapted to recycling systems. In particular, the improvement of comminution technologies is one of the main actions to improve the quality of recycled plastics. The aim of this work is to point out suitable comminution processes for different types of plastic waste. Laboratory comminution tests have been carried out under different conditions of temperature and sample pre-conditioning adopting as refrigerant agents CO2 and liquid nitrogen. The temperature has been monitored by thermocouples placed in the milling chamber. Also different internal mill screens have been adopted. A proper procedure has been set up in order to obtain a selective comminution and a size reduction suitable for further separation treatment. Tests have been performed on plastics coming from medical plastic waste and from a plant for spent lead batteries recycling. Results coming from different mill devices have been compared taking into consideration different indexes for representative size distributions. The results of the performed tests show as cryo-comminution improves the effectiveness of size reduction of plastics, promotes liberation of constituents and increases specific surface size of comminuted particles in comparison to a comminution process carried out at room temperature. | non-battery |
Religiosity and spirituality (R/S) have been shown to be related to better outcomes in many health service areas, including drug abuse treatment. The latter area, however, lacks a fully emergent empirical framework to guide further study. Moreover, although scientists have tested isolated hypotheses, no comprehensive process model has been designed and validated, limiting conceptual development as well. This paper reviews the relevant R/S and health research literature with a primary focus on drug treatment processes. Then a conceptual model is suggested to guide future incremental study of R/S assessment and intervention development. Implications for addiction health services include increased efforts to empirically validate R/S interventions, to increase practitioner competencies in this area, and to disseminate relevant research findings.
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Supercapacitors are high capacitive energy storage devices and find applications where rapid bursts of power are required. Thus materials offering high specific capacitance are of fundamental interest in development of these electrochemical devices. Graphene oxide based nanocomposites are mechanically robust and have interesting electronic properties. These form potential electrode materials efficient for charge storage in supercapacitors. In this perspective, we investigate low cost graphene oxide based nanocomposites as electrode material for supercapacitor. Nanocomposites of graphene oxide and polyvinyl alcohol were synthesized in solution phase by integrating graphene oxide as filler in polyvinyl alcohol matrix. Structural and optical characterizations suggest the formation of graphene oxide and polyvinyl alcohol nanocomposites. These nanocomposites were found to have high specific capacitance, were cyclable, ecofriendly and economical. Our studies suggest that nanocomposites prepared by adding 0.5% wt/wt of graphene oxide in polyvinyl alcohol can be used an efficient electrode material for supercapacitors. | battery |
Exploring highly efficient electrocatalysts toward oxygen reduction and evolution reactions are critical for the development of rechargeable zinc–air batteries. As a novel class of electrocatalyst, transition metal nanoparticles encapsulated within nitrogen-doped carbon have been regarded as competitive alternative to replace noble metal electrocatalysts. Herein, we report successful synthesis of high-density iron nanoparticles encapsulated within nitrogen-doped carbon nanoshell (Fe@N–C) by solid-phase precursor׳s pyrolysis of dicyandiamide and ammonium ferric citrate. The resulting Fe@N–C material shows excellent bifunctionality for ORR and OER in alkaline medium compared to state-of-the-art commercial Pt/C and IrO2, which demonstrates high performance and cycling durability in zinc–air battery as efficient oxygen electrocatalyst. | battery |
LiNi1-yMyO2 (M = Ga, In and Tl, y = 0.010, 0.025 and 0.050) with small y were synthesized by the combustion method by calcining in an O2 stream at 750 °C for 36 h. XRD analyses, SEM observation and measurement of the variation of discharge capacity with the number of cycles were carried out. All the samples had the R
The transition metal oxides such as LiMn2O4 [1–3], LiCoO2 [4–6] and LiNiO2 [7–16] have been investigated as cathode materials for lithium secondary batteries. LiMn2O4 is very cheap and does not bring about environmental pollution, but its cycling performance is not good. LiCoO2 has a large diffusivity and a high operating voltage, and it can be easily prepared. However, it has a disadvantage that it contains an expensive element Co. LiNiO2 is a very promising cathode material since it has a large discharge capacity and is relatively excellent from the viewpoints of economics and environment. However, its preparation is very difficult as compared with LiCoO2 and LiMn2O4.
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Graphene-decorated LiFePO4 composite is synthesized for the first time through in-situ pyrolysis and catalytic graphitization, in which glucose and a trace amount of FeSO4 are employed as the graphene source and catalyst precursor, respectively. Under Ar/H2 (95:5) atmosphere at 750 °C, FeSO4 is thermally reduced to Fe nano-particles (Fe NPs) and glucose is pyrolyzed to carbon fragments first, followed by the in-situ growth of graphene sheets directly on the LiFePO4 nano-particles (LFP NPs) surface through the realignment of carbon fragments under the catalytic effect of the Fe NPs. The graphene sheets not only form a compact and uniform coating layer throughout the LFP NPs, but also stretch out and cross-link into a conducting network around the LFP particles. The LiFePO4@graphene composite displays a high reversible specific capacity of 167.7 mAh g−1 at 0.1C rate, superb rate performance with discharge capacity of 94.3 mAh g−1 at 100C rate and much prolonged cycle life. The remarkable electrochemical improvement is attributed to both electric and ionic conductivity increase as a result of in-situ grown graphene coatings along the LFP surface and the graphene network intrinsically connecting to the LFP particles. | battery |
As a potential energy carrier, hydrogen has surged up the priority list as part of broader decarbonization efforts and strategies to build or acquire clean energy economies. Driven by renewable electricity, electrochemical water splitting (WS) promises an ideal long-term, low-carbon way to produce hydrogen, with the ability to tackle various critical energy challenges. To improve the efficiency of electrocatalytic water splitting, electrocatalysts with enhanced conductivity, more exposed active sites, and high intrinsic activity are crucial for decreasing the energy gap for the rate-determining step (RDS) and subsequently improving the conversion efficiency. The incorporation of multidimensional imperfections has been demonstrated to be efficient for modulating the electron distribution and speeding up the electrocatalysis kinetics during electrocatalytic processes and this is now attracting ever-increasing attention. Herein, in this review, we summarize recent progress relating to the regulation of electrical behavior and electron distributions for the optimization of electrocatalytic water-splitting performance via defect engineering. With an emphasis on the beneficial aspects of the hydrogen economy and an in-depth understanding of electron redistribution caused by defect effects, we offer a comprehensive summary of the progress made in the last three to five years. Finally, we also offer future perspectives on the challenges and opportunities relating to water-splitting electrocatalysts in this attractive field.
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In the present communication, we report on recent researches for optimizing the performance of a primary organic-based Li-air cell. These researches focus on new processing technologies for a high capacity and high rate capable carbon cathode, and the development of oxygen selective membranes based on polysiloxane and methacrylate–polysiloxane copolymers. These membranes, generally classified as silicone rubbers exhibit high permeability for oxygen and impede water transport from the atmosphere into the Li-air cell and solvent loss from the cell into the atmosphere. | battery |
Self-supported gel polymer electrolyte (GPE) was prepared based on copolymer, poly(methyl methacrylate–acrylonitrile–vinyl acetate) (P(MMA–AN–VAc)). The copolymer P(MMA–AN–VAc) was synthesized by emulsion polymerization and the copolymer membrane was prepared through phase inversion. The structure and the performance of the copolymer, the membrane and the GPE were characterized by FTIR, NMR, SEM, XRD, DSC/TG, LSV, CA, and EIS. It is found that the copolymer was formed through the breaking of double bond CC in each monomer. The membrane has low crystallinity and has low glass transition temperature, 39.1°C, its thermal stability is as high as 310°C, and its mechanical strength is improved compared with P(MMA–AN). The GPE is electrochemically stable up to 5.6V (vs. Li/Li+) and its conductivity is 3.48×10−3 Scm−1 at ambient temperature. The lithium ion transference number in the GPE is 0.51 and the conductivity model of the GPE is found to obey the Vogel–Tamman–Fulcher (VTF) equation. | battery |
Four type of MnOx (MnO2, Mn2O3, Mn3O4, MnO) hierarchical microspheres assembled by rod-like building blocks are synthesized by a facile hydrothermal process with/without a consequent calcination. The morphology and structure of these hierarchical microspheres are confirmed by XRD, SEM, TEM, HRTEM, XPS and BET measurements. The electrochemical properties of the four hierarchical microspheres are investigated in terms of cycling stability and rate capability. Specific capacities of 240, 396, 271 and 810mAhg−1 can be achieved after 100 cycles at 0.5C for MnO2, Mn2O3, Mn3O4 and MnO, respectively. Even at a high rate of 2C, MnO microspheres can still deliver a reversible capacity of 406mAhg−1. Their superior electrochemical properties might be attributed to the secondary nanostructure in the MnOx microspheres, which could effectively shorten the diffusion pathway of Li+, tolerate the structural stress caused by Li+ insertion/extraction, reduce the side reactions with electrolyte, and restrain the self-aggregation of nanomaterials. | battery |
The stability of aluminum and nickel as a current collector was investigated at high potentials in the presence of 0.5M NaPF6 or 0.1M NaBF4 dissolved in EC:DEC (1:1wt.-%). Cyclovoltammetry showed that nickel is unstable under experimental conditions, whereas aluminum is electrochemically stable and can be used as a current collector. The feasibility of sodium-based dual-ion cells was studied with self-prepared graphite electrodes in the presence of both electrolytes. The cells showed a fairly stable reversible specific capacity of 15mAh/g for NaBF4 and 55mAh/g for NaPF6. | battery |
Systemic lupus erythematosus (SLE) is a complex clinical syndrome, elements of which remain poorly understood. Although recognized over 140 years ago when Kaposi recorded the systemic nature and manifestations of the disease, CNS involvement represents one of the least understood aspects of SLE. This knowledge gap remains despite the fact that up to 75% of adults and children with SLE will, at some point over the course of the disease and to different extents, experience the various disabling effects of neuropsychiatric SLE (NPSLE). Indeed, after decades of research, our understanding of the underlying pathophysiology of NPSLE, in particular, remains limited. Numerous factors contribute to the immune dysfunction that occurs in SLE, including genetic, environmental and hormonal influences, and the contributory or predisposing components that lead to neurological tropism of disease in some patients have not been clearly demonstrated. Features of NPSLE pathogenesis that might be directly linked to clinical manifestations have been identified; however, the complexity and variety of NPSLE symptoms and the clinical overlap with other psychiatric disorders continue to make accurate diagnosis difficult and time-consuming. Thus, efforts to define biomarkers of NPSLE are needed to improve prediction of disease outcomes and guide treatment. In this article, we review the manifestation and pathogenesis of NPSLE, focusing on the features that might aid identification of potential biomarkers.
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The present study deals with genotoxicity assessment of freshwaters using caged carp (Cyprinus carpio). Carps were transplanted from a fish-farm to three differently polluted sites in eastern Croatia. Two polluted sites were situated in the river Drava, downstream from the cities of Belišće and Osijek, while the reference site was in the Nature Park Kopački rit, a preserved wetland area with limited anthropogenic influence. Exposure lasted for 3 weeks and was repeated for 3 years (2002–2004). DNA damage was assessed in erythrocytes of the exposed animals by the Comet assay and micronucleus test (MNT). In order to evaluate possible differences in stress responses to polluted water in situ and in aquaria a laboratory exposure was performed with water from the studied location in the second year of the study. Carp from the sites with high anthropogenic influence (Belišće and Osijek) had higher average DNA damage as expressed in both the MNT and Comet assay. Of the two, the Comet assay appeared to be more sensitive following both caging and aquaria exposures. The results from this study suggest that 3 weeks caging exposure of C. carpio may be a useful strategy to monitor for genotoxic agents in freshwater ecosystems. | non-battery |
Poly(aniline-co-o-aminophenol) (copolymer) with nanostructured network has been synthesized in the presence of ferrocenesulfonic acid, using repeated potential cycling between −0.10 and 0.86V (versus SCE). The sizes of the fibers in the nanostructures can be controlled by the number of the cycles during copolymerization. The presence of ferrocenesulfonic acid possessing a larger molecular size with positive charges is favorable for the formation of nanostructures. The SEM images reveal a fact that the copolymer films synthesized under different cycles are constructed of interwoven fibers with average diameters in a range of 70–107nm. The copolymer with the nanostructured network deposited on a platinum foil offers a convenient way to study directly the electrochemical property of nanostructures and can effectively catalyze the electrochemical oxidation of catechol in the Na2SO4 solution with pH 5.0. It was found that the electrochemical oxidation of catechol was affected by the sizes of the copolymer fibers. Evidence is that its anodic peak potential increases with increasing the diameter of the fibers in the nanostructures. The copolymer synthesized in the presence of ferrocenesulfonic acid has a good electrochemical activity at pH≤9.0, a larger usable potential window and faster electron transfer ability compared with the copolymer synthesized in the absence of ferrocenesulfonic acid. | battery |
The lattice doping has been widely used to improve the electrochemical performances of Li-rich cathode materials but the roles of the introduced foreign atoms are still not very clear. Herein, a series of Li2Ru1- x Ti x O3 solid solutions have been synthesized and the roles of Ti doping on the structural and electrochemical properties of Li2RuO3 have been comprehensively investigated. The Rietveld refinement exhibits that the interlayer spacing gradually shortens with increasing Ti content. This shrinkage is favorable to the layered structure stability but increases the lithium diffusion barrier. Galvanostatic measurements show that Li2Ru0.8Ti0.2O3 possesses the best cyclability with 196.9 and 196.1 mAh g−1 for charge and discharge capacity retaining after 90 cycles, respectively. Cyclic voltammetry scanning indicates that Ti dopant promotes the formation of more peroxo- or superoxo-like species but reduces the initial coulumbic efficiency. Results of electrochemical impedance spectroscopy display that Ti doping reduces the charge transfer impedance, which facilitates the lithium-ion diffusion across the electrolyte-electrode interface and improves the electronic conductivity. Li2Ru0.8Ti0.2O3 exhibits the best electrochemical performance owing to the balance among all the factors discussed above. This study also offers some new insights into optimizing the electrochemical performances of Li-rich cathode materials through the lattice doping. | battery |
A simple and fast technique to grow free standing, open ended germanium nanotubes is demonstrated using template assisted electrodeposition from a room temperature ionic liquid. Germanium nanotubes as long as 2μm could be grown using this technique. We also show the possibility for the growth of core-shell structures. The technique demonstrated is not limited to the growth of Ge, but can be extended to grow other semiconductor nanotubes and core-shell structures. | battery |
Purpose SM-88 (D,L-alpha-metyrosine; racemetyrosine) is a novel anti-cancer agent, used with melanin, phenytoin, and sirolimus (SMK Therapy). This pilot first-in-human study characterized the safety, tolerability, and efficacy of SMK Therapy in subjects with advanced metastatic cancer. Methods All subjects (n = 30) received SMK Therapy for an initial 6 week Cycle (5 days on, 2 off per week) and continued if well tolerated. Safety signals, clinical response, overall survival, progression free survival (PFS), and quality of life changes were assessed. Results The most common drug related adverse events were hyperpigmentation and rash. All drug related adverse events were mild to moderate in intensity. Following treatment with SMK Therapy, 4 subjects achieved complete response, 6 partial response, and 17 stable disease according to Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 (total clinical benefit 90%). Responses were observed within 6 weeks, and continued to improve, with 3 complete and 3 partial responders achieving best response after at least 3.2 months. Durable stable disease was observed, lasting a median duration of 11 months (range 1–31 months). Median overall survival for all subjects was 29.8 months, and median PFS was 13 months. Following 6 weeks of treatment, most (83.3%) subjects showed an improvement in Eastern Cooperative Oncology Group (ECOG) score and an improvement in the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ 30) global health status (baseline 61.2 ± 25.0; end of Cycle 1 80.7 ± 14.7; n = 29; p < 0.001). Conclusions The results of this study support continued development of SM-88.
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Primary Na/MnO2 cells are expected to gain importance for replacement of primary Li/MnO2 cells in future akin to the Na-ion cells as alternative for Li-ion cells. Amorphous MnO2 is prepared by a drop-wise addition of KMnO4 solution to MnSO4 solution, and coin cells of Na/MnO2 are fabricated in a non-aqueous electrolyte of Na salt. The electrochemical impedance spectroscopy (EIS) data provides a high resistance of Na metal due to the surface passive film. On subjecting the cell for discharge, the surface film causes a delay response of the cell voltage and the closed circuit voltage reaches the normal discharge level following dielectric breakdown of the film. The EIS data measured at different stages of cell discharge are subjected to non-linear least square fitting with the aid of an appropriate equivalent circuit. The impedance parameters are examined to throw light on state-of-charge of Na/MnO2 primary cells. | battery |
Quantum dot-sensitized solar cells (QDSSCs) based on TiO2 film photoanode incorporated with different amounts of graphene are fabricated and their photovoltaic performances are investigated. The results show that the CdS QDSSC incorporating 0.8wt.% graphene in TiO2 photoanode demonstrates a maximum power conversion efficiency of 1.44%, 56% higher than that without graphene. The performance improvement is ascribed to the increased CdS adsorption, the reduction of electron recombination and back-transport reaction as well as the enhancement of electron transport with the introduction of graphene. | battery |
Background Duration of untreated psychosis (DUP) has been significantly associated with poor clinical and social outcomes in First Episode Psychosis (FEP) patients, but an association with cognitive outcomes has not been clearly established. Method Seventy-seven consecutively admitted, drug-naïve patients with FEP were assessed at baseline and at 1month and 6months. Underlying dimensions of DUP (general prodrome and positive, negative and disorganisation symptoms) were assessed using the Symptom Onset in Schizophrenia (SOS) inventory (Perkins et al., 2000). To assess the effect of DUP on the neuropsychological status of the patients, a linear mixed-effect model was fitted to each neuropsychological dimension. These models included a dichotomised version of DUP (short versus long duration) as a fixed effect, several adjusting variables to account for patient differences, and a random effect to incorporate the longitudinal structure of the data. Results Patients with a short duration of untreated negative symptoms (DUNS) or a short duration of untreated positive symptoms (DUPS) outperformed patients with a long duration of untreated symptoms on memory tasks and a pre-attentional visual task but not on measures of verbal fluency, attention, reaction time, visual processing and executive functions. Conclusions This study provides additional support for an early intervention to shorten DUP to facilitate a better outcome in memory and attentional domains of FEP patients. | non-battery |
Storage and management of energy is becoming a more and more important problem every day, especially for electric and hybrid vehicle applications. Li-ion battery is one of the most important technological alternatives for high capacity energy storage and related industrial applications. State of Health (SoH) of Li-ion batteries plays a critical role in their deployment from economic, safety, and availability aspects. Most, if not all, of the studies related to SoH estimation focus on the measurement of a new parameter/physical phenomena related to SoH, or development of new statistical/computational methods using several parameters. This paper presents a new approach for SoH estimation for Li-ion battery systems with multiple battery cells: The main idea is a new circuit topology which enables separation of battery cells into two groups, main and test batteries, whenever a SoH related measurement is to be conducted. All battery cells will be connected to the main battery during the normal mode of operation. When a measurement is needed for SoH estimation, some of the cells will be separated from the main battery, and SoH estimation related measurements will be performed on these units. Compared to classical SoH measurement methods which deal with whole battery system, the proposed method estimates the SoH of the system by separating a small but representative set of cells. While SoH measurements are conducted on these isolated cells, remaining cells in the main battery continue to function in normal mode, albeit in slightly reduced performance levels. Preliminary experimental results are quite promising, and validate the feasibility of the proposed approach. Technical details of the proposed circuit architecture are also summarized in the paper. | battery |
Copper silicide-coated graphite as an anode material was prepared by the sequential employments of plasma enhanced chemical vapor deposition (PECVD) and radio frequency magnetron sputtering (RFMS) method at 300°C. The silicon-coated graphite exhibited an initial discharge capacity of 540mAh/g with 76% coulomb efficiency, and the discharge capacity was sharply decreased down to 50% of initial capacity after 30 cycles, probably due to large volume changes during the charge–discharge cycling. Copper silicide-coated graphite, however, exhibited an initial discharge capacity of 480mAh/g with higher retention capacity of 87% even after 30 cycles, probably due to the enhanced interfacial conductivity. The copper silicide film on the graphite surface played as the active anode material of lithium secondary batteries via the reduction of interfacial resistance and mitigation of volume changes during repeated cycles. | battery |
Increased propensity for dendritic lithium electrodeposition during sub-ambient temperature operation has been widely reported in lithium battery systems, yet is not fully understood. In the present paper, a mathematical model is developed to quantify the dendritic growth rate during lithium electrodeposition at sub-ambient temperature. This model builds on a diffusion–reaction framework presented recently by Akolkar [J. Power Sources 232 (2013) 23–28]. Using a steady-state diffusion model with a concentration-dependent diffusion coefficient, the lithium-ion concentration depletion in the stagnant Nernst diffusion boundary layer near the lithium surface is modeled. A surface electrochemical reaction model is then employed to correlate the lithium concentration depletion to the dendrite growth rate. Temperature effects on the lithium-ion transport and its electrochemical surface reaction are incorporated in the model via an Arrhenius-type temperature-dependence of the diffusion coefficient and the apparent charge transfer coefficient. It is shown that lowering the system temperature has the effect of increasing the lithium-ion diffusion resistance and decreasing the surface film thickness – conditions favorable for the formation of dendrites during lithium electrodeposition. | battery |
A pair of polychotomous random variables (Y1,Y2)⊤=:Y
Polychotomous ordinal data arise in many areas of statistical analysis and are particularly frequent in surveys and observational studies. Several questions may be asked to measure people’s feelings on a matter of interest, as well as some relevant information reported on a monotonic scale. Examples include individuals’ perceived social class or their educational attainments. Since it is usually acknowledged that these types of data possess levels that can be “naturally” ordered, it is desirable to account for this feature in the model’s representation and estimation. Specific methodologies were developed to address this issue, starting from the seminal works of Aitchison and Silvey (1957) and Snell (1964), up to their modern forms of the cumulative link models (CLM; McCullagh 1980) in which ordinal responses are expressed within the wider class of generalized linear models (GLMs; Nelder and Wedderburn 1972). An interesting historical review discussing merits (and limits) of each of the above contributions can be found in the monograph of Greene and Hensher (2010).
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Promoting oxygen reduction and evolution reactions using effective catalysts hold broad significance for clean energy utilization. In this work, hollow N-doped carbon networks (N-CNs) were fabricated via interfacial dehalogenation of polyvinyl dichloride (PVDC) on 2D CoAl-layered double hydroxide (LDH) with the presence of N source and used as efficient bifunctional catalysts. BET results revealed that as-made N-CNs had very large specific surface area (SSA, 550.4m2 g−1 for 900°C-annealed N-CN (N-CN9)) and abundant pore hierarchy. Additionally, interconnected graphitic carbon walls, forming separated cells, can ensure high electrical conductivity, which were formed after acid-leaching of metallic components. Remarkably, N-CN9 showed excellent bifunctional activities towards oxygen reduction and evolution reactions. Moreover, N-CN9 assembled Zn-air battery (ZAB) exhibited an operating voltage of 1.35V under applied current density of 1.0mAcm−2, which is highly comparable to that of PtRu/C catalyst. Moreover, due to the pore hierarchy and large SSA, N-CN9-ZAB possessed much better rate capability and cycling stability than that of PtRu/C-ZAB. | battery |
Electrodes are routinely washed to remove electrolyte deposits, salt, and high boiling point solvents prior to analysis with surface-sensitive techniques. The effect of washing on the surface films of graphite electrodes from LiCoO2/graphite cells, which contained varying amounts of vinylene carbonate (VC), was investigated by comparing the microstructure and chemical composition. We confirmed that there are two different kinds of films on the surface of the electrodes: one at low and one at high VC content concentration. Far from being limited to remove extraneous salt deposits from the surface of the sample, DMC washing was found to completely remove one and to affect the composition of deeper strata in the other. | battery |
Hitting the headlines quite a lot in the past six months, space exploration systems are one of the more interesting technical challenges for PV devices. Not one but perhaps four probes will be on their way to our nearest planetary neighbor, Mars. The success or failure of these missions will hinge on their on-board PV power sources — providing power for experiments and for getting the data back to Earth. But PV is not the only power source option, and the alternatives present challenges which PV makers must face. | non-battery |
The compound Li X NiVO4 (X = 0.8, 1.0, 1.2) is prepared by a solid-state reaction method. The vibrational analysis of the compound is studied using Fourier transform infra red (FTIR) and Raman spectroscopic techniques. A new peak at 1039cm−1 is observed for Li1.2NiVO4 in the FTIR analysis and indicates the presence of Li+ OV bond interactions. The FTIR and Raman characteristic bands for cubic inverse spinel structure are observed for all samples. Using the diatomic approximation method, the bond length and the bond order of the compound with various Li compositions are calculated. The valence state of the compounds is calculated using the Pauling valence sum rule and is found to be nearly 5.2 for all compositions of Li X NiVO4 (X = 0.8, 1.0, 1.2). | battery |
Developing highly efficient and economically sustainable electrocatalysts with bifunctions for the oxygen reduction reaction and oxygen evolution reaction is crucially important in practical implementation of rechargeable zinc-air batteries. Herein, a novel Cu-based electrocatalyst composed of Cu97P3-x-y O x N y nanoparticles supported on N, P co-doped carbon is synthesized straightforward by the annealing of the Cu-phytic acid gel under an argon and ammonia gases atmosphere. The Cu97P3-x-y O x N y /N, P co-doped carbon catalyst displays the outstanding catalytic performance for both the oxygen evolution reaction and oxygen reduction reaction in alkaline solution, which is ascribed to the synergistic effect of Cu97P3-x-y O x N y and N, P co-doped carbon. Meanwhile, the primary and rechargeable zinc-air batteries assembled by the Cu97P3-x-y O x N y /N, P co-doped carbon catalyst exhibit a high specific capacity and remarkable charge-discharge cycle stability, which are comparable to that of the benchmark Pt/C and IrO2. The energy density of the catalyst reaches to 737 Wh kgZn −1. To the best of our knowledge, few Cu-based electrocatalysts is reported for rechargeable zinc-air batteries. | battery |
Nanowire Na0.35MnO2 was prepared by a simple and low energy consumption hydrothermal method; its electrochemical performance as a cathode material for aqueous asymmetric supercapacitors in Na2SO4 solution was investigated. Due to the nanowire structure its capacitance (157 F g−1) is much higher than that of the rod-like Na0.95MnO2 (92 F g−1) from solid phase reaction although its sodium content is lower. When it is assembled into an asymmetric aqueous supercapacitor using activated carbon as the counter electrode and aqueous 0.5 mol L−1 Na2SO4 electrolyte solution, the nanowire Na0.35MnO2 shows an energy density of 42.6 Wh kg−1 at a power density of 129.8 W kg−1 based on the total weight of the two electrode material, higher than those for the rod-like Na0.95MnO2, with an energy density of 27.3 Wh kg−1 at a power density of 74.8 W kg−1, and that of LiMn2O4. The new material presents excellent cycling behavior even when dissolved oxygen is not removed from the electrolyte solution. The results hold great promise for practical applications of this cathode material since sodium is much cheaper than lithium and its natural resources are rich. | battery |
The high-rate charge/discharge performance of L3DC alloy is improved by heat treatment in pure Ar or 10% H2/Ar atmosphere at 300°C and 400°C. L3DC, a commercially available LaNi5-type alloy, is used as the negative electrode for high-power nickel–metal hydride batteries. The structural modification, morphology, and surface composition of the heat-treated alloys are examined through X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray energy dispersive spectrometry (EDS). Electrochemical performance of the alloy is also tested with an electrochemical workstation and a charge/discharge tester. Results show that the low- and room-temperature rate discharge performance and high-temperature rate charge performance of the alloy can be improved by heat treatment in 10% H2/Ar atmosphere. Moreover, the low- and room-temperature rate charge performance and high-temperature rate discharge performance can only be enhanced by heat treatment in pure Ar atmosphere. Heat treatment can affect not only the speed of proton transport in the solid phase, but also the hydrogen reaction on the alloy surface. | battery |
In general, carbon materials with high specific surface area (SSA), well-balanced pore size distributions, and appropriate content of heteroatom functionalities are essential to enhance the performance of electric double layer capacitors (EDLCs) for capacitive energy storage. In this study, a low-cost biological waste-stiff silkworm was first used as precursor for the synthesis of well-developed microporous carbon (SSMC) material by simple steps of carbonization and further activation. The SSMC was endowed with ultra-high SSA (2523m2 g−1), large pore volume (1.37m3 g−1), and high content of heteroatom functionalities (∼3.5 at% N and ∼5.1 at% O). EDLCs employed SSMC as active material showed high specific capacitance of 304Fg−1 and 256Fg−1 at current densities of 1Ag−1 and 20Ag−1, respectively, suggesting the good rate capability. Symmetric-two-electrode test in aqueous electrolyte also delivered the specific capacitance of 235Fg−1 with the energy density of ∼7.9Whkg−1. The findings confirmed the feasible way that using the eco-friendly biomass raw material to construct high performance capacitive energy storage device. | battery |
This paper presents an approach to concurrent toolpath planning for multi-material layered manufacturing (MMLM) to improve the fabrication efficiency of relatively complex prototypes. The approach is based on decoupled motion planning for multiple moving objects, in which the toolpaths of a set of tools are independently planned and then coordinated to deposit materials concurrently. Relative tool positions are monitored and potential tool collisions detected at a predefined rate. When a potential collision between a pair of tools is detected, a dynamic priority scheme is applied to assign motion priorities of tools. The traverse speeds of tools along the x -axis are compared, and a higher priority is assigned to the tool at a higher traverse speed. A tool with a higher priority continues to deposit material along its original path, while the one with a lower priority gives way by pausing at a suitable point until the potential collision is eliminated. Moreover, the deposition speeds of tools can be adjusted to suit different material properties and fabrication requirements. The proposed approach has been incorporated in a multi-material virtual prototyping (MMVP) system. Digital fabrication of prototypes shows that it can substantially shorten the fabrication time of relatively complex multi-material objects. The approach can be adapted for process control of MMLM when appropriate hardware becomes available. It is expected to benefit various applications, such as advanced product manufacturing and biomedical fabrication. | non-battery |
Children with Developmental Coordination Disorder (DCD) experience considerable difficulties coordinating and controlling their body movements during functional motor tasks. Thus, it is not surprising that children with DCD do not perform well on tests of physical fitness. The aim of this study was to determine whether deficits in motor coordination influence the ability of children with DCD to perform adequately on physical fitness tests. A case–control study design was used to compare the performance of children with DCD (n =70, 36 boys, mean age=8y 1mo) and Typically Developing (TD) children (n =70, 35 boys, mean age=7y 9mo) on measures of isometric strength (hand-held dynamometry), functional strength, i.e. explosive power and muscular endurance (Functional Strength Measurement), aerobic capacity (20m Shuttle Run Test) and anaerobic muscle capacity, i.e. muscle power (Muscle Power Sprint Test). Results show that children with DCD were able to generate similar isometric forces compared to TD children in isometric break tests, but were significantly weaker in three-point grip strength. Performance on functional strength items requiring more isolated explosive movement of the upper extremities, showed no significant difference between groups while items requiring muscle endurance (repetitions in 30s) and items requiring whole body explosive movement were all significantly different. Aerobic capacity was lower for children with DCD whereas anaerobic performance during the sprint test was not. Our findings suggest that poor physical fitness performance in children with DCD may be partly due to poor timing and coordination of repetitive movements. | non-battery |
Lithium sulfur (Li–S) batteries are one of the most promising next generation battery chemistries with potential to achieve 500–600 W h kg−1 in the next few years. Yet understanding the underlying mechanisms of operation remains a major obstacle to their continued improvement. From a review of a range of analytical studies and physical models, it is clear that experimental understanding is well ahead of state-of-the-art models. Yet this understanding is still hindered by the limitations of available techniques and the implications of experiment and cell design on the mechanism. The mechanisms at the core of physical models for Li–S cells are overly simplistic compared to the latest thinking based upon experimental results, but creating more complicated models will be difficult, due to the lack of and inability to easily measure the necessary parameters. Despite this, there are significant opportunities to improve models with the latest experimentally derived mechanisms. Such models can inform materials research and lead to improved high fidelity models for controls and application engineers.
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The influence of several processing conditions on the phase formation and electrochemical performance of LiNi0.5Mn0.5O2 powders, obtained by freeze drying method, is studied. Thermal processing in pellets at maximum heating rate promotes better crystallographic ordering of hexagonal LiNi0.5Mn0.5O2 and maximum capacity values irrespectively of chemical composition of the precursor. Instead, intense mechanical processing of precursors exerts considerable negative effect on the electrochemical performance. Cathode materials containing superstoichiometric amount of lithium (Li1.3Mn0.5Ni0.5O2+δ) demonstrate reversible capacity values up to 190mAh/g between 2.5 and 4.6V. | battery |
The electrochemical reactivity of the ball-milled ilmenite FeTiO3 and ilmenite nanoflowers with lithium has been investigated. The electrode assembled with the ilmenite nanoflowers delivers better electrochemical performance than that of the milled material during charging and discharging in the potential range of 0.01 and 3V vs. Li/Li+. The ilmenite nanoflowers demonstrate the capacity of ca. 650mAhg−1 during the first discharge, and a reversible capacity of approximately 200mAhg−1 in the course of the first 50 cycles. The possible reaction mechanism between ilmenite and lithium was studied using cyclic voltammetry and transmission electron microscopy. The first discharge involves the formation of an irreversible phase, which is either LiTiO2 or LiFeO2. Subsequently, the extraction–insertion of lithium happens in a reversible manner. It was also observed that the lithium storage might be significantly improved if the electrode was prepared in the form of a nanocomposite of FeTiO3 with carbon. | battery |
Super-hydrophilic conducting polyaniline was prepared by surface modification of polyaniline using tetraethyl orthosilicate in water/ethanol solution, whereas its conductivity was 4.16Scm−1 at 25°C. And its electrochemical capacitance performances as an electrode material were evaluated by the cyclic voltammetry and galvanostatic charge/discharge test in 0.1M H2SO4 aqueous solution. Its initial specific capacitance was 500Fg−1 at a constant current density of 1.5Ag−1, and the capacitance still reached about 400Fg−1 after 5000 consecutive cycles. Moreover, its capacitance retention ratio was circa 70% with the growth of current densities from 1.5 to 20Ag−1, indicating excellent rate capability. It would be a promising electrode material for aqueous redox supercapacitors. | battery |
To explore the benefit finding (BF) relationship between colorectal cancer (CRC) survivors and their spousal caregivers, and to discover the dyadic impact of BF on quality of life (QOL) in CRC survivor and spousal caregiver couples. | non-battery |
This study adopts high-concentration ether electrolytes to improve high-rate capability, cycling stability, and Coulombic efficiency (CE) for lithium ion batteries with lithium anode. A series of ether-based electrolytes including lithium bis(fluorosulfonyl)imide (LiFSI)-glyme/ethylene carbonate (EC), LiFSI-glyme/EC, LiFSI-diglyme/EC, LiFSI-triglyme/EC, LiFSI-tetraglyme (G4)/EC, and LiFSI-1,3-dioxolane (DOL)/EC, along with commonly used LiPF6-DEC/EC were prepared to delineate the influences of concentration, chain length, molecular structure (linear or ring ether), and EC additive on the electrochemical performance of Li anodes. An optimum composition for ether-based electrolyte was determined resulting in significant improvement in anti-flammability as well as CE at both low and high rates. At ultra-high current density operation (e.g. 6 mA cm−2), the CE was 95.5 and 97.1% with 3 M LiFSI-G4/EC and 3 M LiFSI-DOL/EC, respectively. Using 1 M LiPF6 carbonate-based electrolyte tend to grow a needle-like dendritic structure when depositing lithium metal on Cu foils, whereas high-concentration ether electrolyte promotes a knot-like and rounded Li metal microstructure. High concentration EC-based electrolytes, are capable of facilitating Li+ almost in tandem with solvent molecules, thereby reducing the number of free molecules, reducing the chance of side reaction with Li metal, and subsequently inhibiting the formation of dendritic Li structures. | battery |
Objective To investigate the probable cortical excitability changes in DMD by electrophysiological means. Methods Sixteen cases with DMD, 10 age-matched control children (CC) and 10 healthy adult volunteers (AC) were studied with a transcranial magnetic stimulation (TMS) test battery composed of central conduction time, cortical silent period and paired TMS paradigm. Results There were no significant differences between DMD and CC groups except for lower amplitude motor responses in DMD cases. These two groups showed a similar pattern of excitability with less short interval intracortical inhibitions and shorter silent period durations as compared to the AC subjects. Conclusions The electrophysiological tests performed in our DMD patients did not reveal abnormalities caused particularly by the disorder. Significance TMS excitability studies performed in DMD boys may not provide findings other than those related to the developmental age. | non-battery |
To investigate the crystal structure and electrochemical performance of samples synthesized under different microwave solid-state synthesis condition, a series of Li3V2(PO4)3 samples has been synthesized at five different temperatures for 3–5min and at 750°C for various time. The as-synthesized Li3V2(PO4)3 samples are characterized and studied by ICP-AES analysis, X-ray diffraction (XRD), Rietveld analysis, scanning and transmission electron microcopy (SEM and TEM). At relatively lower temperature (650°C) and very short reaction time (3min), pure phase of Li3V2(PO4)3 could be synthesized in microwave irradiation field. The crystal structure and Li atomic fractional coordinate present a significant deviation upon the change of microwave irradiation temperature and time. Relatively, the diffusion ability of lithium cations and the electrochemical performance are affected. Under the proper reaction temperature and time, the carbon-free samples MW750C5m and MW850C3m show the best specific discharge capacity 126.4 and 132mAhg−1 at the voltage range of 3.0–4.3V, near the reversible cycling of two lithium ions per Li3V2(PO4)3 formula unit (133mAhg−1). At the voltage range of 3–4.8V, the sample MW750C5m presents the best initial specific charge capacity of 197mAhg−1, equivalent to the reversible cycling of three lithium ions per Li3V2(PO4)3 formula unit (197mAhg−1). The initial discharge capacity, the samples MW750C5m and MW850C3m present high specific discharge capacity 183.4 and 175.7mAhg−1, respectively. The relationship among microwave irradiation condition, crystal structure, lithium atomic fractional coordinates and the electrochemical performance have been discussed in detail. | battery |
Nano-metal embedded Li4Ti5O12/C composites (Li4Ti5O12/M/C samples labeled as Li4Ti5O12/Sn/C-L, Li4Ti5O12/Sn/C-H, Li4Ti5O12/Sb/C-L, Li4Ti5O12/Sb/C-H, Li4Ti5O12/Bi/C-L and Li4Ti5O12/Bi/C-H, respectively) as high capacity anode were synthesized by sol-gel and high temperature solid state reaction methods. The physical properties of Li4Ti5O12/M/C were detected by X-ray diffraction (XRD), scanning microscopy (SEM), transmission electron microscopy (TEM) and elemental analysis. All composites were completely coated by a thin carbon layer. Besides the Li4Ti5O12/Bi/C-L, other Li4Ti5O12/M/C samples were composed of spherical-like aggregate particles. Nano-M was embedded between inner Li4Ti5O12 and outer carbon layer. Their electrochemical performances were studied by galvanostatic cycle and cyclic voltammograms (CVs). These analyses show that Li4Ti5O12/Sn/C-L, Li4Ti5O12/Sn/C-H, Li4Ti5O12/Sb/C-H, Li4Ti5O12/Bi/C-H delivered a reversible capacity of 231.9, 308.1, 235.9 and 213.5mAhg−1 at 500th cycle on current density of 200mAg−1, respectively, while Li4Ti5O12/C composite only delivered a capacity of 197.6mAhg−1 at the same conditions. The results demonstrated that metal M can play an important role on high capacity performance of Li4Ti5O12-based anode when it was embedded between inner “zero-strain” Li4Ti5O12 and outer carbon coating layer. Their stable cycle performance owning to the co-effect of Li4Ti5O12 as the structural stabilizer and carbon layer as the volume change buffer for preventing the volume change caused by M during cycling. This work provides an effective way to improve the discharge capacity of Li4Ti5O12-based anodes. | battery |
Wrought Mg-Al-Pb-RE strips of different thicknesses are synthesized via extrusion and used as the anodes in Mg-air batteries. We find that, compared to other Mg-Al-Pb-RE samples, the 5 mm-thick strip exhibits greater stability and higher discharge voltage plateaus for long time (10 h). Its anodic efficiency at 10 mA cm−2 reaches 64.1%, which is even higher than pure magnesium and AZ31 magnesium alloy. The outstanding performance of the 5 mm-thick Mg-Al-Pb-RE anode strip is attributed to its unique microstructure favourable for anodic dissolution. Furthermore, the correlations between microstructure features and electrochemical performance for the wrought Mg-Al-Pb-RE strips are also systematically defined. | battery |
LiNi0.6Mn0.2Co0.2O2 (C622) is one of the Ni-rich layer-structured cathode materials with a high capacity, but it suffers from a poor cycling stability and rate capability. In this study, Li1.3Al0.3Ti1.7(PO4)3 (LATP), a NASICON-type lithium-conductor, is coated on C622 by a sol–gel process to overcome the shortcomings of C622. We find that a 0.5 wt% coating of LATP on C622 significantly improves the cell performance including the discharge capacity, rate capability, and cycling stability. The pristine and LATP-coated samples were analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). In addition, various electrochemical analyses such as cyclic-voltammetry (CV), galvanostatic intermittent titration technique (GITT), and electrochemical impedance spectroscopy (EIS) are conducted to determine the reason for the improvement of the cell performance. The cell performance of C622 is enhanced by a coating amount of less than 1.0 wt% and the overall performance degrades with the increase of the coating amount. The electrochemical analyses reveal that a high lithium-ion diffusion coefficient and a low interfacial resistance are the reasons for the improved cell performance; however, our study demonstrates that an excessive coating may degrade the cell performance, thereby acting as a barrier against the movement of lithium ions. | battery |
An analytical study of the effect of diffusioosmosis caused by the concentration gradient of hydrogen ions on the isothermal transport of water in a fully hydrated membrane of a polymer electrolyte fuel cell (PEFC) is presented. A capillary tube or slit with a negatively charged wall is chosen to model the nanopores of the membrane. The electric double layer adjacent to the capillary wall may have an arbitrary thickness relative to the capillary radius and its electrostatic potential distribution is determined as the solution of the Poisson–Boltzmann equation. Solving a modified Navier–Stokes equation, the fluid velocity in the axial direction of the capillary induced by the macroscopic electric field and protonic concentration gradient is obtained as a function of the radial position in closed forms. The results for the local and averaged electrokinetic velocities in the capillary show that the effect of diffusioosmosis on the water transport in the membrane of a PEFC can be significant in comparison with that of electroosmosis under low-potential-difference operations. | battery |
An electroplated copper/tin (Cu/Sn) anode with a layered structure is described that minimizes the high-voltage irreversible capacity observed in an electroplated Sn anode at a potential over 1V. The high-voltage irreversible capacity is caused by the electrolyte decomposition at the catalytic site of the Sn anode. In the electroplated Cu/Sn anode, the upper Cu layer effectively suppresses the exposure of the newly formed Sn surfaces, resulting in the absence of the high-voltage irreversible capacity. Therefore, the electroplated Cu/Sn anode exhibits a higher cycle performance than the electroplated Sn anode. | battery |
Children in elementary school, along with college adults, were tested on a battery of basic mathematical tasks, including digit naming, number comparison, dot enumeration, and simple addition or subtraction. Beyond cataloguing performance to these standard tasks in Grades 1 to 5, we also examined relationships among the tasks, including previously reported results on a number line estimation task. Accuracy and latency improved across grades for all tasks, and classic interaction patterns were found, for example, a speed-up of subitizing and counting, increasingly shallow slopes in number comparison, and progressive speeding of responses especially to larger addition and subtraction problems. Surprisingly, digit naming was faster than subitizing at all ages, arguing against a pre-attentive processing explanation for subitizing. Estimation accuracy and speed were strong predictors of children’s addition and subtraction performance. Children who gave exponential responses on the number line estimation task were slower at counting in the dot enumeration task and had longer latencies on addition and subtraction problems. The results provided further support for the importance of estimation as an indicator of children’s current and future mathematical expertise. | non-battery |
A comprehensive matrix of composite poly(ethyleneoxide) (PEO)-based solid-state electrolytes was developed in order to systematically study a number of variables and their impact upon the electrochemical properties of the resulting materials. The different parameters studied in the fabrication of these materials include: (i) the lithium electrolyte salt type, (ii) the ether oxygen to lithium ratio, (iii) the molecular weight of PEO, (iv) the type of ceramic additive used, either aluminum oxide (Al2O3), silicon oxide (SiO2), or titanium oxide (TiO2), (v) the particle size of the additives used, and (vi) the concentration of additive (wt.%). The standard lithium salt used for the preparation of these electrolytes was lithium trifluoromethanesulfonate (lithium triflate or LiSO3CF3), which served as the baseline electrolyte salt. Other lithium salts investigated include: lithium perchlorate (LiClO4) and lithium bis-trifluoromethanesulfonimide (LiN(SO2CF3)2). Conductivity measurements were performed for each electrolyte membrane over a wide temperature range (23–100°C). In addition, cyclic voltammetry measurements were performed on selected PEO membranes as a function of temperature to determine the impact of various parameters upon the electrochemical stability. It was observed that the parameter that displayed the most significant effect upon the PEO-base polymer conductivity was the lithium salt type employed. The lithium triflate salt-containing PEO polymers demonstrated the best mechanical properties before and after heat treatment. Ceramic fillers also appear to enhance the mechanical properties of PEO polymer electrolytes at temperatures above the melting point of PEO (60–70°C). In addition to investigating the electrochemical characteristics of the composite membrane, solid state 7Li NMR characterization was performed to study ionic mobility by measuring spectral line widths and lithium self-diffusion coefficients. It was determined that ceramic nanoparticle additives can enhance the Li+ diffusivity without a corresponding increase in polymer segmental mobility. | battery |
Li2Na2Ti6O14 and its Ti-site substitution Li2Na2Ti5.9M0.1O14 (M = Al, Zr, V) are prepared by a solid-state reaction method and used as anode materials for lithium-ion batteries. It is found that metal doping can effectively enhance the electronic conductivity and ionic diffusion coefficient of Li2Na2Ti6O14. Especially for Li2Na2Ti5.9Al0.1O14, it reveals the highest electronic conductivity (1.02 × 10−9 S cm−1) and lithium ion diffusion coefficient (8.38 × 10−15 cm2 s−1) among all the samples. As a result, Li2Na2Ti5.9Al0.1O14 reveals the best electrochemical performance. It can deliver a charge specific capacity of 270.3 mAh g−1 at 50 mA g−1. Even cycled at 1000 mA g−1, it still can present a charge capacity of 180.7 mAh g−1. All these enhanced lithium storage capabilities of Li2Na2Ti5.9Al0.1O14 should be attributed to the increased electronic/ionic conductivities and the decreased charge transfer resistance induced by Al doping. Besides, in-situ X-ray diffraction observation also confirms that the structural change of Li2Na2Ti5.9Al0.1O14 is highly reversible process for lithium storage. | battery |
We present a novel concept of an implantable active microport based on micro technology that incorporates a high-resolution volumetric dosing unit and a drug reservoir into the space of a conventional subcutaneous port. The controlled release of small drug volumes from such an “active microport” is crucial e.g. for innovative methods in cancer treatment or pain therapy. Our microport system delivers a flow rate in the range of 10–1,000 μl/h and enables a patient-specific release profile. The core of our device is a two-stage piezoelectric micropump. It features a backpressure-independent volumetric dosing capability i.e. a stable flow rate is ensured up to a backpressure of 30 kPa. The stroke volume and hence the resolution of the mircopump is voltage controlled and can be preset between 10 and 200 nl. A miniaturized high-performance electronic control unit enables freely programmable dosing profiles. This electronic circuit is optimized for both energy consumption and weight which are both essential for a portable device. The data of an implemented pressure sensor are used to permanently monitor the dosing process and to detect a potential catheter occlusion. A polyurethane soft lithography process is introduced for the fabrication of the prototype. Therewith, a compact multilayer system has been developed which measures only 50 × 35 × 25 mm3.
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Disturbances in the default mode network (DMN) have been described in many neurological and psychiatric disorders including Parkinson’s disease (PD). The DMN is characterized by basal activity that increases during rest or passive visual fixation and decreases (“deactivates”) during cognitive tasks. The network is believed to be involved in cognitive processes. We examined the DMN in PD patients on dopaminergic medication with normal cognitive performance compared to age- and gender-matched healthy controls (HC) using fMRI and three methodological procedures: independent component analysis of resting-state data, analysis of deactivation during a complex visual scene-encoding task, and seed-based functional connectivity analysis. In the PD group, we also studied the effect of dopaminergic medication on the DMN integrity. We did not find any difference between the PD and HC groups in the DMN, but using the daily levodopa equivalent dose as a covariate, we observed an enhanced functional connectivity of the DMN in the posterior cingulate cortex and decreased activation in the left parahippocampal gyrus during the cognitive task. We conclude that dopaminergic therapy has a specific effect on both the DMN integrity and task-related brain activations in cognitively unimpaired PD patients, and these effects seem to be dose-dependent. | non-battery |
The current study investigates both gray and white matter changes in non-demented Parkinson’s disease (PD) patients with varying degrees of mild cognitive deficits and elucidates the relationships between the structural changes and clinical sequelae of PD. Twenty-six PD patients and 15 healthy controls (HCs) were enrolled in the study. Participants underwent T1-weighted and diffusion tensor imaging (DTI) scans. Their cognition was assessed using a neuropsychological battery. Compared with HCs, PD patients showed significant cortical thinning in sensorimotor (left pre- and postcentral gyri) and cognitive (left dorsolateral superior frontal gyrus [DLSFG]) regions. The DLSFG cortical thinning correlated with executive and global cognitive impairment in PD patients. PD patients showed white matter abnormalities as well, primarily in bilateral frontal and temporal regions, which also correlated with executive and global cognitive impairment. These results seem to suggest that both gray and white matter changes in the frontal regions may constitute an early pathological substrate of cognitive impairment of PD providing a sensitive biomarker for brain changes in PD. | non-battery |
Tailoring the structure of Ni-rich ternary layered cathode is considered as an effective way to solve its poor cycling and rate capability. Herein, a special structure of Ni0.6Co0.2Mn0.2(OH)2 precursor, in which strips composed of lamellar primary particles are vertically inserted, is rationally designed through feasible industrialized co-precipitation process. Particularly, precursor possesses a loose interior and dense exterior structure by observation of cross section. After sintering, LiNi0.6Co0.2Mn0.2O2 (NCM622) cathode shows monodispersed microspheres whose external surface is tightly wrapped rod-like primary particles. Moreover, NCM622 microspheres inherits the properties of Ni0.6Co0.2Mn0.2(OH)2 precursor, displaying hollow structure and aligned primary particles along the radial direction. NCM622 cathode shows optimal electrochemical properties in the voltage window of 2.8–4.4 V. It displays a revisable capacity of 142.4 mAh g−1 (79.3% for capacity retention ratio) after 300 cycles under current density of 1 C. A reversible capacity of 110.3 mAh g−1 can be obtained after 500 cycles even at current density of 3 C, and corresponding capacity decay rate is only 0.068% for each cycle. The tailored cathode has great potential applications in batteries of high-power and long calendar life as well as provides an idea for structural design of high nickel cathode. | battery |
Tailoring carbon based negative electrode by grafting electroactive 9,10-phenanthrenequinone molecules on porous carbon drastically improves the performance of a carbon/Ni(OH)2 hybrid electrochemical capacitor. The grafted-quinone moieties add a Faradaic contribution to the double layer capacitance of carbon leading to a significant increase of the charge stored by the full devices. Good cyclability is ensured due to the strong bond between 9,10-phenanthrenequinone molecules and the carbon surface. More importantly, by increasing the total capacity, the grafting improves the energy density of the full hybrid device while maintaining fast charge/discharge kinetics and thus without affecting the power density. | battery |
A fundamental understanding of the anodic stabilities of electrolytes is important for the development of advanced high-voltage electrolytes. In this study, we calculated and systematically compared the oxidation stabilities of monomeric solvents and anions, and bimolecular solvent–solvent and anion–solvent systems that are considered to be high-voltage electrolyte components, using ab initio calculations. Oxidation stabilities of solvent or anion monomers without considering specific solvation molecules cannot represent experimental oxidation stabilities. The oxidation of electrolytes usually forms neutral or cationic radicals, which immediately undergo further reactions stabilizing the products. Oxidatively driven intermolecular reactions are the main reason for the lower oxidation stabilities of electrolytes compared with those of monomeric compounds. Electrolyte components such as tetramethylene sulfone (TMS), ethyl methyl sulfone (EMS), bis(oxalate)borate (BOB−), and bis(trifluoromethane)sulfonamide (TFSI−) that minimize such intermolecular chemical reactions on oxidation can maintain the oxidation stabilities of monomers. In predictions of the theoretical oxidation stabilities of electrolytes, simple comparisons of highest occupied molecular orbital energies can be misleading, even if microsolvation or bulk clusters are considered. Instead, bimolecular solvent complexes with a salt anion should be at least considered in oxidation calculations. This study provides important information on fundamental and applied aspects of the development of electrolytes. | battery |
We studied the reading performance of 340 consecutive, Italian-speaking aphasics in order to evaluate the clinical features of deep dyslexia, the functional impairments underlying semantic paralexias, and their neuranatomical correlates. Semantic paralexias were observed in 9/340 subjects (2.4%). Our data and a review of the literature show that most deep dyslexics suffer from superficial and deep vascular damage in the territory of the left middle cerebral artery, and that they are relatively young, well-educated individuals, in the chronic stage of their disease. In these subjects, perisylvian damage might be mainly responsible for damage to sublexical grapheme–phoneme Conversion (GPC) procedures, and extrasylvian damage for lexical–semantic impairment. Semantic paralexias might originate in the right hemisphere, or in left perilesional regions. The functional impairment underlying deep dyslexia was analyzed with specific reference to the summation hypothesis, i.e., to the hypothesis that in reading, GPC procedures interact with lexical–semantic information, thus blocking semantically incorrect responses. On this account, semantic paralexias should only occur when, in the presence of lexical–semantic damage, GPC rules are disrupted to the point that the interaction can no longer take place. In agreement with the hypothesis, only cases with co-occurring lexical–semantic and GPC damage produced semantic paralexias; and, these were the subjects with the most severe GPC damage. The inability to apply approximately 45% GPC mappings is the critical level of sublexical damage that no longer allows GPC procedures to interact with lexical–semantic information. | non-battery |