锂离子电池高镍层状正极材料循环稳定性研究进展

Research progress in nickel-rich layered cathode materials cycling stability for lithium-ion batteries

高镍层状正极材料LiNi_(x)M_(1-x)O_(2)(x≥0.8,M=Co,Mn,Al等)由于高比容量、高工作电压和低成本,近年来成为混合动力电动汽车和电动汽车(EV)高能量密度锂离子电池最有前景的正极材料。电动汽车技术的进步要求锂离子电池具有约350 Wh·kg^(-1)的高能量密度、500 km的续航里程以用于商业应用。然而,高镍层状正极材料的容量快速衰减和结构不稳定性阻碍了其市场化应用。本文总结了高镍层状正极材料性能衰减的根本性问题,通过元素掺杂、元素比例、表层重构、颗粒排布、颗粒间填充、颗粒尺寸和单晶化等方面对改善高镍层状正极材料循环稳定性的最新进展进行了归纳,并指出未来可以尝试元素和结构协同构筑高结构强度高镍正极材料,以从根本上解决其深度脱锂下的结构和热稳定性难题,为高镍层状正极材料提供改性新工艺和新方法。

The nickel-rich layered cathode materials LiNi_(x)M_(1-x)O_(2)(x>0.8,M=Co,Mn,Al,etc.)have become the most promising cathode materials for hybrid electric vehicles and electric vehicle(EV)high energy density lithium-ion batteries in recent years due to its high specific capacity,high operating voltage,and low cost.The further development of electric vehicle technology requires the commercial application of lithium-ion batteries with a high energy density of approximately 350 Wh·kg^(-1)and a range of 500 km.However,the rapid capacity decay and structural instability of nickel-rich layered cathode materials hinder their market application.In this paper,the fundamental issue of performance degradation in nickel-rich layered cathode materials was summarized,and the latest progress and perspectives in improving the cycling stability of nickel-rich layered cathode materials through element doping,element ratio,surface reconstruction,particle arrangement,interparticle filling,particle size,single crystal transformation,and other aspects were summarized.It is pointed out that efforts could be made to construct high structural strength nickel-rich cathode materials through the coordination of elements and structures to fundamentally solve the structural and thermal stability problems under deep delithiated state,providing modified new processes and methods for nickel-rich layered cathode materials.