锂离子电池正极材料磷酸钒锂制备方法研究进展

Research progress on preparation of Li_(3)V_(2)(PO_(4))_(3) cathode material for lithiumion batteries

单斜结构的磷酸钒锂[Li_(3)V_(2)(PO_(4))_(3)]材料与其他锂离子电池正极材料相比具有较高的工作电压(3.0~4.8 V)、良好的离子迁移率和优良的热稳定性,是一种具有竞争优势和发展前景的大功率锂离子电池正极材料,成为了近年来研究的热点。综述了锂离子电池正极材料磷酸钒锂的结构特点及其充放电机理。磷酸钒锂的常用合成方法有碳热还原法、水热法、溶胶-凝胶法及流变相法等,着重阐述了磷酸钒锂的不同合成方法对所制备样品的形貌和电化学性能的影响。分析总结了不同合成方法的改进方法,以改善磷酸钒锂正极材料电子导电性和锂离子扩散系数较低的问题。最后,针对磷酸钒锂正极材料在锂离子电池的应用中所存在的问题展望了该材料未来可能的发展方向和研究热点。指出需要优化材料的制备方法以改善材料的颗粒形貌、提高电子导电率和扩散系数等,进而改善材料的循环性能、倍率性能和充放电性能等;需要改进制备流程、提高实验的安全性、简化反应流程和减少制备成本等,以实现磷酸钒锂正极材料的工业化应用。

Compared with other lithium-ion battery cathode material,lithium vanadium phosphate[Li_(3)V_(2)(PO_(4))_(3)]material with monoclinic structure has higher working voltage(3.0~4.8 V),good ion mobility and excellent thermal stability.It is a high-power lithium-ion battery cathode material with competitive advantages and development prospects,and has become a research hotspot in recent years.The structural characteristics of lithium vanadium phosphate and its charging and discharging mechanism were reviewed.The common synthesis methods of lithium vanadium phosphate included carbothermic reduction,hydrothermal method,sol-gel method and fluidization method,and the influence of different synthesis methods and processes of lithium vanadium phosphate on the different morphologies and electrochemical properties of the prepared samples was emphasized.The improvement methods of different synthesis methods are analyzed and summarized to improve the shortco-mings and defects of low electronic conductivity and lithium ion diffusion coefficient of lithium vanadium phosphate cathode materials.Finally,In view of the problems existing in the application of vanadium lithium phosphate cathode material in lithium ion battery,the possible development direction and research focus of this material in the future were prospected.It was pointed out that the preparation method of materials needed to be optimized to improve the particle morphology,electronic conductivity and diffusion coefficient of materials,so as to improve the cycle performance,rate performance and charge/dis-charge performance of materials.It was necessary to improve the preparation process,improve the safety of the experiment,simplify the reaction process and reduce the preparation cost in order to realize the industrial application of lithium vanadium phosphate cathode materials.