摘要
兼具高能量密度、高功率密度、长循环寿命性能的正极材料是当下电池储能材料研究的重点,也是储能市场的重要需求。富锂锰基正极材料(LRMO)因其极高的放电比容量(≥250 mAh/g)、较高的工作电压(4.2~4.5 V vs.Li/Li^(+))、低成本且环境友好等优点成为当下最具应用前景的正极材料之一。虽然金属阳离子和阴离子依次或同时进行的氧化还原反应使LRMO材料的容量超过了传统层状氧化物,但首次不可逆容量高、循环和倍率性能较差等一系列的问题阻碍了其工程化应用,这与材料中阴离子氧化还原反应紧密相关。本文首先介绍了LRMO材料的晶体结构,然后基于分子轨道理论,回顾了LRMO材料的能带结构与阴阳离子氧化还原反应的联系,总结了阴离子氧化还原反应对富锂锰基正极材料的影响,包括高容量、不可逆的氧流失、过渡金属离子迁移。同时,分别从过渡金属比例调节、表面修饰、离子掺杂三个方面总结了近些年国内外研究人员针对阴离子氧化还原反应造成的负面影响设计的改性策略。最后展望了LRMO材料理论研究与应用研究的大致方向。
Cathode materials with high energy density,high power density,and long cycle life are the focus of current research on battery energy storage materials and are also in high demand in the energy storage market.Lithium-rich manganese-based oxide(LRMO)cathode materials are some of the most promising cathode materials owing to their high discharge specific capacity(≥250 mAh/g),high operating voltage(4.2~4.5 V vs.Li/Li^(+)),low cost,and environmental friendliness.Although the sequential or simultaneous redox of cations and anions of LRMO materials results in their enhanced capacity compared with other conventional layered oxides,several problems such as high irreversible capacity for the first cycle and poor cycling and rate performance hinder their engineering applications,which are closely related to the anionic redox reactions in the materials.This paper introduces the crystal structure of LRMO materials and then reviews the relationship between the energy band structure of LRMO materials and anionic redox reactions based on molecular orbital theory.In addition,the effects of anionic redox reactions on LRMO cathode materials,including high capacity,irreversible oxygen loss,and transition metal ion migration,are summarized.Moreover,recent modification strategies for mitigating the negative effects of anionic redox reactions are summarized from three perspectives:transition metal ratio adjustment,surface modification,and ion doping.Finally,the paper discusses the future theoretical and application direction of LRMO materials.
作者
周俊飞
蔡星鹏
丁浩
崔孝玲
ZHOU Junfei;CAI Xingpeng;DING Hao;CUI Xiaoling(College of Petrochemical Technology,Lanzhou University of Technology;Gansu Key Laboratory of Low Carbon Energy and Chemical Engineering,Lanzhou 730050,Gansu,China)
出处
《储能科学与技术》
CAS
CSCD
北大核心
2022年第12期3733-3740,共8页
Energy Storage Science and Technology
基金
甘肃省产业支撑计划项目(2021CYZC-18)
甘肃省重点研发项目(21YF5GA079)。
关键词
锂离子电池
富锂锰基
正极材料
阴离子氧化还原
改性策略
lithium-ion batteries
lithium-rich manganese based
cathode material
anionic redox
modification strategy
