磷酸铁锰锂材料的合成方法及结构改性的研究进展

Advances in synthesis methods and structural modification of LiMnFePO_(4)materials

锂离子电池因具有比能量高、循环使用寿命长、无记忆效应等特点而备受关注,并已广泛应用于日常生活中。在已有的锂离子电池正极材料中,磷酸铁锰锂正极材料具有能量密度高、放电比容量大、电压平台高等优点,是一种具有前景的锂离子电池正极材料,然而由于其低导电率和离子迁移速率慢等问题,一直制约着其发展。通过分析磷酸铁锰锂不同铁锰比例、颗粒尺寸及形貌对电化学性能的影响,指出铁锰物质的量比为0.5∶0.5的小粒径多孔球状颗粒对提高电化学性能有积极的影响;并介绍了采用Mg、Ti、Ni等离子掺杂或表面包覆改性方法对其进行优化,材料的性能会得到改善;最后对磷酸铁锰锂的发展趋势提出了一些建议,指出对合成工艺的改进和开展更深入的理论研究仍是今后的研究重点。

Lithiumion batteries have attracted much attention because of their high specific energy,long cycle life and no memory effect,and have been widely used in daily life.Among the existing cathode materials for lithiumion batteries,lithium iron manganese phosphate cathode material is a promising cathode material for lithiumion batteries with the advantages of high energy density,high specific capacity of discharge,high voltage plateau,etc.However,due to the problems of its low electrical conductivity and slow ion mobility rate,it has been restricting its development.In this paper,by analysing the effects of different Fe-Mn ratios,particle sizes and morphologies on the electrochemical performance of lithium iron manganese phosphate,it was pointed out that the small particle size porous spherical particles with an Fe-Mn ratio of 0.5∶0.5 had a good effect on improving the electrochemical performance.And it was also introduced that the optimization by using the methods of plasma doping of Mg,Ti,and Ni or the modification method of surface capping,the performance of the material would be more satisfactory.Finally,some suggestions on the development trend of lithium ferromanganese phosphate were put forward,pointing out that the improvement of the synthesis process and the development of more indepth theoretical research were still the focus of future research.