A novel PPESK fibrous membrane separator based on electrospinning technique for lithium-ion battery
In order to improve the low porosity, poor thermal stability and insufficient electrolyte wettability of commercial polyolefin separator, the novel PPESK fibrous membrane separator has been fabricated via electrospinning for the use of lithium-ion batteries. By the use of high-speed collection drum, the tensile strength of the electrospinning oriented PPESK fiber membranes increase significantly and reaches 18.9 MPa. Hot oven testing shows that oriented PPESK fiber membranes are thermally size stable at a high temperature of 220 °C. The oriented PPESK fiber membrane exhibits high level of porosity (83%) and excellent electrolyte uptake (720%). Moreover, the ionic conductivity increases to 1.85 mS cm -1 compared with the 0.41mS cm -1 of commercial Celgard 2400 separator. In addition, the lithium-ion battery assembled with electrospinning oriented PPESK fiber membrane shows high capacity retention, stable cycle performance and excellent rate capability. Therefore, the electrospinning oriented PPESK fiber membrane is likely to be a promising candidate of high-power lithium-ion battery owing to its comprehensive outstanding characteristics.
Progress in Organic Coatings, editorial, vol. 58, issues 2-3
As you read this, you have just opened the second special issue of Progress in Organic Coatings dealing with the papers delivered at Coating Science International. This second conference in a series, CoSi 2006, was held in Noordwijk, the Netherlands from June 26 to June 30, 2006 at the Hotels van Oranje. This meeting was held in an amicable atmosphere, experiencing also for the second time nice weather, between 111 participants from 17 different countries. In total, 35 papers and 22 posters were presented. We are of course tempted to testify that the conference was a success but it may be fairer to refer to an independent review by Dirk Meine of Vincentz Network [Eur. Coat. J. 9 (2006) 64–66]. The authors were invited to submit a full paper to Progress in Organic Coatings, subject to the usual reviewing conditions. As last year, the Editor-in-Chief Prof. Gordon Bierwagen, asked the organisers to act as guest editors and we gladly accepted this invitation. The result is an issue containing 22 full papers of contributions to CoSi 2006.
A Lithium/Dissolved Sulfur Battery with an Organic Electrolyte
Prototype cells of the configuration Li/~5M S as , THF, have been characterized with regard to capacity, rate, and rechargeability. Virtually 100% of the theoretical capacity could be realized at 50°C at rates below 1.0 mA/cm2. In high rate cell configurations, 75% cathode utilization is possible at ~4 mA/cm2 (C/3–C/4 rate). The capacities at high rate are enhanced by Lewis acids, although the ultimate cause of rate limitation is passivation of the current collector by discharge products. The self‐discharge rates of Li in contact with 4–5M S (as ) solutions reveal capacity losses of 0.5%/day at 25°C to 4.4%/day at 71°C. Based on the experimental results, a practical energy density of ~300 W‐hr kg−1 is possible using a standard cell design. Results on the battery's rechargeability are briefly reviewed.