单晶高镍三元正极材料:挑战与策略  

Single-Crystal Nickel-Rich Cathode Materials:Challenges and Strategies

作　　者：黄辰悦 郑鸿飞 秦宁 王灿沛 王利光 陆俊[1] Chenyue Huang;Hongfei Zheng;Ning Qin;Canpei Wang;Liguang Wang;Jun Lu(College of Chemical and Biological Engineering,Zhejiang University,Hangzhou 310027,China)

机构地区：[1]浙江大学化学工程与生物工程学院,杭州310027

出　　处：《物理化学学报》2024年第9期35-55,共21页Acta Physico-Chimica Sinica

基　　金：国家自然科学基金(52272241)资助项目。

摘　　要：进一步提高锂离子电池的能量密度、循环寿命和安全性对电动汽车的普及至关重要。三元层状正极材料因其高比容量、低温性能良好、成本较低等优势,近年来在动力电池领域备受关注。高镍化和高电压化被认为是提高三元材料能量密度的有效途径。然而,基于传统多晶三元正极的高镍化和高压化可能会显著降低材料的循环稳定性和热安全性,设计单晶三元正极材料被认为可以有效缓解高压多晶三元正极稳定性问题的可行途径。但是,单晶三元正极仍然面临着离子传输动力学受阻、非均匀荷电状态、晶格参数各向异性变化、阳离子混排、化学机械降解等挑战。因此,本文从三元正极材料的本质结构演化角度系统地分析和总结了多晶与单晶结构失效的共性问题。此外,还归纳了单晶高镍三元材料的合成工艺调控、元素掺杂、表界面改性等策略,梳理了结构设计与电化学性能之间的构效关系,并对单晶高镍三元正极材料的未来发展方向进行了展望,能够为高比能三元正极材料的开发提供理论指导。Over the past three decades,significant advancements in lithium-ion battery technology have greatly improved human convenience,particularly in today's thriving electric vehicle industry.Further enhancements in the energy density,cycle life,and safety of lithium-ion batteries are crucial for the widespread adoption of electric vehicles.In recent years,transition metal layered oxides have garnered significant attention in the industrial power battery sector due to their advantages,including high specific capacity,commendable low-temperature performance,and cost-effectiveness.Increasing the nickel content and adjusting the charging cut-off voltage are recognized as effective means to enhance the energy density of transition metal layered oxides.However,these strategies tend to degrade cycling stability and thermal safety in conventional polycrystalline layered cathode materials.Benefiting from the mechanical stability of intact primary particles,the single-crystal structure of layered cathode materials can effectively mitigate intergranular cracking issues associated with high charging voltages.Nevertheless,due to the intrinsic structural properties of layered materials,singlecrystal structures still face challenges related to sluggish Li+transport kinetics,heterogeneous state of charge,anisotropic changes in lattice parameters,cation mixing,and chemo-mechanical degradation.The temporal and spatial evolution of the physicochemical properties within the internal microstructure of materials still requires comprehensive analysis using advanced operando characterization techniques.Currently,there is limited understanding of the intricate interplay between thermodynamics and kinetics in the synthesis process of single-crystal cathode materials.A more profound exploration of the structural degradation and synthesis mechanisms of single-crystal materials will serve as a fundamental basis for targeted modification strategies.Regrettably,existing single-crystal synthesis processes and modification approaches still fall short

关 键 词：锂离子电池 层状正极材料 高镍 单晶结构 失效机制 结构演化 改性策略 

分 类 号：O646[理学—物理化学]