摘要
富镍三元正极材料(NCM/NCA)因其兼具高能量密度与优异倍率性能,在电动汽车与储能领域得到广泛应用。随着镍含量的提升,材料可逆比容量显著提高,但高镍化同时引发材料结构与化学稳定性下降,导致电池循环寿命缩短,并增大安全隐患。本文系统梳理了富镍三元正极材料的主要失效机理,并分析其对电池性能的影响规律。其中,Li^(+)/Ni^(2+)阳离子混排引起部分锂离子位点失活,降低材料可逆容量;材料高活性表面导致其在存储及充放电循环中易发生表面/界面副反应,加速材料表面不可逆相变及电解液分解;同时,正极颗粒在连续充放电过程中因各向异性应力积累而产生微裂纹,导致结构坍塌,并增加电解液与正极的接触面积,加剧界面副反应。针对上述问题,近年来提出了多种改性策略,包括构建氧化物或有机物涂层以提升界面稳定性,元素掺杂以优化结构稳定性和离子扩散动力学,浓度梯度设计以兼顾高比容量与界面稳定性,以及单晶化以缓解颗粒裂纹和界面副反应。最后,本文对富镍三元正极材料未来的研究方向进行展望,为下一代高能量密度锂离子电池研究提供参考。
Nickel-rich layered oxide(NCM/NCA)cathodes have been widely applied in electric vehicles and energy storage systems owing to their high energy density and excellent rate capability.The reversible capacity of NCM/NCA considerably enhances with increasing nickel content but reduces the structural and chemical stability.This ultimately reduces the battery cycle life and increases safety concerns.In this review,the major degradation mechanisms of NCM/NCA cathodes are systematically summarized,and their impacts on the electrochemical performance of these cathodes are elucidated.Specifically,Li^(+)/Ni^(2+)cation mixing deactivates the lithium-ion sites and reduces the reversible capacity.The high surface reactivity of NCM/NCA makes it prone to surface and interfacial reactions during storage and cycling,thereby accelerating irreversible phase transitions and electrolyte decomposition.Furthermore,the accumulation of anisotropic stress during repeated cycling induces microcrack formation within cathode particles,ultimately causing structural collapse and increasing the electrodeelectrolyte contact area;these changes further aggravate interfacial reactions.To address these issues,diverse modification strategies have been proposed in recent years.These include applying surface coatings with oxides or organics to enhance interfacial stability,elemental doping to improve structural stability and ion diffusion kinetics,concentrationgradient designs to achieve high capacity and interfacial stability,and single-crystal engineering to mitigate particle cracking and interfacial reactions.Finally,the future research directions of nickel-rich cathode materials are discussed,providing insights into the development of next-generation high-energy-density lithium-ion batteries.
作者
黄小荣
刘健达
芦大伟
易斌
徐云
秦啸天
HUANG Xiaorong;LIU Jianda;LU Dawei;YI Bin;XU Yun;QIN Xiaotian(Dongguan Power Supply Bureau of Guangdong Power Grid Corporation,Dongguan 523000,Guangdong,China;National Institute of Guangdong Advanced Energy Storage,Guangzhou 510000,Guangdong,China)
出处
《储能科学与技术》
北大核心
2026年第1期129-151,共23页
Energy Storage Science and Technology
基金
南方电网科技项目(031900KC24040028)。
关键词
锂离子电池
富镍三元正极
失效机理
改性策略
lithium-ion battery
nickel-rich ternary cathode
failure mechanism
modification strategy
