高性能锂硫电池正极材料研究进展及构建策略

Development and strategy for cathode materials of advanced lithium sulfur batteries

锂硫电池体系理论上存在高容量和高能量密度特点,但正极材料本身的绝缘性和放电中间产物溶解的特性使锂硫电池的理论容量难以充分发挥,循环性能也有待进一步提升。通过正极材料的改性来解决上述问题是锂硫电池研究的主要途径。本文将正极材料分为碳/硫复合材料、聚合物/硫复合材料、纳米金属化合物/硫复合材料3类,结合限硫机制进行了简要综述,列举了其中代表性的工作,评述了各类材料的优缺点,提出了实用化锂硫电池正极材料性能的评价应考虑极片载硫量、含硫量及电解液用量等条件,阐述了高性能正极材料的构建策略,指出电解液量过高是目前制约锂硫电池比能量进一步提升的关键因素,应当引起足够重视,最后展望了锂硫电池的发展方向。

Lithium-sulfur battery system possesses high capacity and high energy density in theory, but which cannot be realized fully due to the insulating nature of the cathode material itself and the dissolution of its intermediate products. The cycle performances of lithium-sulfur battery are also deteriorated owing to these disadvantages. Modification of the cathode material is the major approach to address the issues described above. Here, combining the polysulfides limiting mechanism, we give a brief review of recent progress on the cathode materials of lithium-sulfur battery, which are classified into three kinds, including nano-carbon/sulfur composites, polymer/sulfur composites and nano-metal compound/sulfur composites, list the representative work, and review the advantages/disadvantages of various cathode materials. From the practical point of view, we suggest that the evaluating to the performances of the cathode materials should be related with some special conditions, such as the sulfur loading, sulfur content of cathode, and the electrolyte amount in battery. Furthermore, we explain the design strategy for high performance cathode materials. It is pointed out that the high electrolyte amount is the key factor which restricts the further enhancement of the specific energy of lithium sulfur battery. At last, the development trend of lithium sulfur battery is prospected.