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锂离子电池作为新型的储能形式,缓解了人们对化石燃料的依赖和日益严峻的环境压力。富锂层状氧化物相比于传统正极材料,由于其低成本和大可逆容量的特性,被誉为最具发展潜力的下一代锂离子电池正极材料之一,尤其是在电动汽车和大规模储能电网领域的应用前景十分广阔。本文从材料的结构类型出发,主要介绍了固溶体结构和复合结构在晶格排布上的差异以及在鉴别这种差异时所采用的一系列表征手段。本文还总结了近年来提出的最具代表性的几种4.5V电压平台产生机理,从不同角度解释了富锂层状氧化物在首次循环过程中表现出异常容量的现象,并结合现有研究阐述了各种机理。此外,也对阻碍富锂层状氧化物进一步发展的重大问题,包括首次不可逆容量损失、循环性能和倍率性能等进行了分析,讨论了表面尖晶石相对材料性能的影响,介绍了几种最典型的改性手段。最后,对富锂层状氧化物正极材料未来的研究方向进行了概述,展望其研究前景。
Lithium-ion battery as a new form of energy storage to ease the people’s dependence on fossil fuels and increasingly severe environmental pressures. Lithium-rich layered oxides are regarded as one of the most promising cathode materials for next-generation lithium-ion batteries due to their low cost and large reversible capacity compared to traditional cathode materials, especially in electric vehicles and large-scale Energy storage grid in the field of application prospects are very broad. Based on the structural types of materials, this paper mainly introduces the differences in the crystal lattice arrangement of solid solution and composite structures and a series of characterization methods used in the identification of such differences. This paper also summarizes the most representative mechanisms of 4.5V voltage platform proposed in recent years and explains the phenomenon that lithium-rich layered oxides exhibit abnormal capacity during the first cycle from different perspectives. Combined with the existing research Various mechanisms are elaborated. In addition, major issues that hinder the further development of lithium-rich layered oxides, including the first irreversible capacity loss, cycle performance and rate performance, were also analyzed. The effects of surface spinel on material properties were also discussed. A typical means of modification. Finally, the future research direction of lithium-rich layered oxide cathode material is summarized and its research prospect is prospected.