Molecular Dynamics Simulations of Li Insertion in a Nanocrystalline V 2 O 5 Thin Film Cathode
The behavior of lithium ion diffusion from an electrolyte into a polycrystalline layered cathode has been studied using molecular dynamics computer simulations. Lithium silicate glass was the model solid electrolyte whilethe cathode was a nanocrystalline vanadia with amorphous V 2 O 5 intergranular films (IGF) between the crystals. Nanosized V 2 O 5 crystals were aligned with their (001) planes parallel to electrolyte/cathode interface, rotated 90° from each other around this interface's normal in order to present two different orientations between the crystal planes for lithium intercalation via the amorphous vanadia IGF. A series of nanocrystalline vanadia cathodes with different IGF thicknesses was simulated to examine the effects of the IGF thickness on lithium transport into the cathodes. Results showed preferential diffusion of Li from the electrolyte into the amorphous vanadia IGF, with some of those Li diffusing into the crystalline V 2 O 5 from the IGF. Results also showed easier lithium diffusion from the IGF into the V 2 O 5 crystal along the (010) direction than along the (100) direction. Additionally, an optimum IGF thickness of 2.5-3.0 nm is suggested as being neither too thick to decrease the capacity of the cathode nor too thin to impede the transport of lithium from glassy electrolyte into the cathode.
Solid state ionics 2
The first part of this proceedings volume deals with application of solid state ionics. Potential application of solid state batteries and fuel cells, sensors, electrochromic windows, and displays are presented. The second part of the Proceedings volume deals with new advances in the theory of solid state ionics. Several approaches such as molecular dynamic relaxation phenomena in solids and ab-initio methods are presented. The third section of the Proceedings volume deals with polymeric electrolytes. Several key issues such as ion-ion and ion polymer interaction and nature of the polymer electrolytes are presented. The polymer dynamics and mechanism of ion transport in polymer electrolytes are discussed. The fourth part of the book deals with mixed conductors and insertion compounds. Physics and chemistry of mixed conductors and their electrochemical properties are presented. The fifth part of the book deals with the general aspects of materials and techniques in solid state ionics. Several new materials with unique properties are presented. Materials processing and fabrication are discussed. Fundamentals of defect chemistry and structure of several glasses are presented. Several in-situ and ex-situ techniques for materials characterization are presented.
Recycling of silicon powder waste cut by a diamond-wire saw through laser-assisted vacuum smelting
Abstract This paper proposes laser granulating technology for recycling harmful silicon powder waste cut by a diamond-wire saw. The silicon block produced by laser was easily melted in a traditional vacuum smelting furnace to form a silicon ingot with a high yield and filling rate, which could reach up to 94.7% and 65.7%, respectively. The removal efficiency of the carbon contamination was 74.2% during laser melting process and reached 86% after 30 min of vacuum smelting. In addition, laser melting process promoted the removal of most metal impurities, such as Al, Na, Ca, Mg, and so on, in the silicon powder waste without introducing any other impurities. The residual impurities could be further removed by vacuum smelting. The experiment revealed that the out capacity of the silicon block melted by a single laser gun was 1.91 kg/h, the energy consumption of laser melting was 2.63 kWh/kg, and the yield of the silicon block exceeded 97% at a laser power of 2000 W, a laser scanning interval of 5 mm, and a scanning speed of 6 mm/s. Therefore, the proposed approach is one of the most simple and efficient silicon powder waste pretreatment methods.