高比能锂硫电池关键材料的研究

Key Materials of High Energy Lithium Sulfur Batteries

锂硫电池具有突出的高比能量优势和原料廉价、环境友好等优点,有望成为新一代高能电池体系,但循环性能差是制约其实用化的主要障碍。本文介绍了锂硫电池的国内外发展水平,综述了锂硫电池在正极材料、电解质、负极及体系方面的重要进展,并着重介绍了防化研究院近5年在这一领域的主要成果:制备了硫化导电高分子材料和介孔炭/硫复合材料两类正极材料,提高了硫的利用率和循环性能,其中后者在提高硫含量上更有优势;开发了高性能黏合剂明胶并设计了多孔正极;探索了适宜的电解液组成;研究了锂负极在锂硫电池特殊环境中的界面特性;集成上述技术,研制出比能量达300Wh/kg以上,100%DOD放电循环100次后容量保持率接近60%的锂硫软包装电池。展望了锂硫电池的研究方向。

Lithium sulfur battery is a promising energy storage system due to its high specific energy density, low cost and environmental friendliness. But poor cycle performance has hindered its practical application. In this paper, the developing levels of lithium sulfur battery are introduced concisely. The important progress on the cathode materials, electrolytes, lithium anode and new battery composition of this battery system are reviewed. Furthermore, some investigation results in recent 5 years in this field of Chemical Defense Institute are mainly introduced. Firstly, two kinds of cathode materials, conducting polymer sulfides and mesoporous carbon/sulfur composites were prepared which improved the sulfur utilization and cycle performance. Compared with conducting polymer sulfides, mesoporous carbon/sulfur composites can embody more sulfur, so were preferable to high energy batteries. Secondly, an electrochemically stable binder, gelatin binder also functioned as a highly adhesive agent and an effective disperser was applied in lithium sulfur batteries. A novel porous sulfur cathode with the gelatin binder was prepared by using a freeze-drying mathod. Thirdly, a suitable electrolyte composition were investigated. Fourthly, the interface performance of lithium anode in lithium sulfur battery were studied. Integrating these technologies, the prototype polymer battery was assembled. It presented the energy density of more than 300Wh/ kg, and showed about 60% remaining capacity after 100 cycles at 100% DOD. Finally, the prospects of the future research on lithium sulfur batteries are proposed.