高镍正极材料微裂纹诱导容量衰减的应对策略研究进展

Research progress on countermeasures for microcrack-induced capacity degradation of Ni-rich cathode materials

随着锂离子电池在电动汽车、储能等领域的广泛应用,其正极材料尤其是钴酸锂、镍钴锰酸锂及镍钴铝酸锂三元正极材料的需求量也随之剧增。然而由于钴资源稀缺,“高镍低钴化”成为近年来锂离子电池行业的重要关注点和发展方向。高镍正极材料(Ni的摩尔分数大于60%)凭借着容量高、成本低廉等优势获得了广泛的关注和研发,其产业化步伐逐渐加快。然而其仍然面临着诸多限制其大规模应用的问题,其中微裂纹的产生诱发的快速容量衰减问题被越来越多的研究证明是常规球状高镍正极材料容量衰减的首要因素。本文综述了近年来针对这一问题的几种典型应对策略的研究进展,包括填隙包覆处理、径向有序设计以及采用高镍单晶正极材料。本文对以上典型应对策略的技术手段、工艺参数和电化学性能进行了总结和归纳。最后对于进一步的研究方向进行了展望。

With the wide application of lithium-ion batteries in the fields of electric vehicles and energy storage,the demand for cathode materials,especially lithium cobalt oxide,lithium nickel-cobalt-manganese oxide and lithium nickel-cobalt-aluminum oxide cathode materials,have increased dramatically.However,due to the scarcity of cobalt resources,“Ni-rich and Co-poor”has become an important concern and direction of development of the lithium-ion battery industry in recent years.Ni-rich cathode materials(Ni mole content higher than 60%)have attracted wide attention due to the advantages of high energy density and cost efficiency,and the pace of industrialization of the materials has accelerated over time.The conventional spherical Ni-rich cathode materials are faced with the problem of rapid capacity fading caused by microcrack formation due to anisotropic volume change.The problem is considered as the dominant factor of capacity fading of spherical Ni-rich cathode materials.In this paper,several strategies to deal with this problem in recent years are reviewed,including interstitial coating,design and synthesis of radially ordered primary particles,and the use of Ni-rich single-crystal cathode materials.These methods are analyzed,evaluated and summarized in detail,and further research direction is prospected.