富锂锰基正极材料阴阳离子氧化还原机制能够提供超过250 mAh g-1的高比容量,使其在高能量密度锂离子电池领域展现出巨大的应用前景.不同于传统O3型富锂锰基正极材料,具有独特氧排列构型的O2型富锂锰基正极材料显示出相对更高的阴离子氧化还原反应可逆性和结构稳定性.受限于材料表面发生的不可逆氧损失、电解液氧化和循环过程中结构完整性对首次库仑效率、倍率性能和循环稳定性等的影响,O2型富锂锰基正极材料的商业化应用进程缓慢.本文主要总结了近年来O2型富锂锰基正极材料的制备方法、晶体结构和储锂机理认识,以及结构调控、抑制电解液氧化和缓解应变效应等改性策略对提升材料容量和循环稳定性的作用机制和功效,并对该材料未来的研究方向进行展望,推进O2型富锂锰基正极材料产业化开发应用.
Research progress of O2-type lithium-rich manganese-based cathode materials
The anionic-cationic redox mechanism of Li-rich manganese-based cathode materials is capable of providing a high specific capacity of more than 250 mAh g 1,which thus indicates the great application prospects in the field of high-energy-density lithium-ion batteries.Discriminate from traditional O3-type Li-rich Mn-based cathode materials,the unique oxygen-arranged configurations of O2-type Li-rich Mn-based cathode materials exhibit the relatively higher redox reversibility and structural stability.Limits of the influence of irreversible oxygen loss occurring on the material surface,electrolyte oxidation and structural integrity during the cycling process on the initial coulombic efficiency,rate performance and cycling stability,the commercial applications of O2-type Li-rich Mn-based cathode materials have been slacken.This paper mainly summarizes the preparation method,understanding of crystal structure and lithium storage mechanism towards O2-type Li-rich Mn-based cathode materials in recent years,as well as the mechanism and efficacy of modification strategies including structure modulation,inhibition of electrolyte oxidation and mitigation of strain effects upon enhancing the capacity and cycle stability of the materials.In addition,the future research direction of O2-type Li-rich Mn-based cathode materials is prospected to promote the industrial development and application.
O2-type lithium-rich manganese-based materialsredox reversibilitystructural stabilitycathode modificationlithium ion battery
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