锂离子电池正极材料钒改性聚阴离子型化合物的研究进展

Recent Progress in Vanadium Modified Polyanionic Compounds as Cathode Materials for Lithium Ion Batteries

聚阴离子型化合物(LiMXOm,M=Fe、Mn、Co、Ni,X=P、Si、S、B、Ti)具有结构稳定、安全性能好等特点,被认为是一种较理想的动力锂离子电池正极材料,但较低的本征电导率严重限制了其实际应用.钒改性可以有效地改善聚阴离子型正极材料的电化学性能,而钒改性方法、钒的用量以及钒的多种价态等造成钒的存在形式复杂多变,分析困难,目前有关钒改性的作用机理仍不清楚.本文简要介绍了钒改性的主要方式,详细综述了钒改性聚阴离子型正极材料磷酸铁锂和硅酸铁锂的研究现状,讨论了钒改性和钒表征的难点,指出了今后该领域的研究方向.

Polyanionic compounds （LiMXOm, M= Fe, Mn, Co, Ni, X= P, Si, S, B, Ti） have been considered as one of the most prom- ising cathode materials for power lithium ion batteries because of their excellent structural stability, good reliability, and high per-formance. However,low intrinsic electrical conductivity has limited their practical applications. Vanadium modifications have been shown to significantly improve the electrochemical performance of the polyanion-type cathode materials. The methods used for vana- dium modifications,the amounts and diversified valence states of vanadium,as well as the difficulties in vanadium identifications, result in the complexities and varieties of vanadium existing forms. Accordingly,the mechanisms of vanadium modifications remain un- clear. In this paper, basic forms of vanadium modifications are briefly introduced, and recent progress in vanadium modified polyanion- type cathode materials, such as LiFePO4 and Li2 FeSiO4 ,is reviewed in detail. The difficulties involved in vanadium modifications and identifications in vanadium modified potyanionic compounds are also discussed. Future research trends in the field of vanadium modi- fied polyanion-type cathode materials for lithium ion batteries are highlighted.