锂离子电池用富锂层状正极材料

摘要

正极材料与负极材料是锂离子电池重要组成部分。目前锂离子电池负极材料比容量通常在300 mAh/g以上,而正极材料比容量始终徘徊在150 mAh/g。正极材料正在成为锂离子电池性能进一步提升的瓶颈。富锂层状正极材料是一类新型正极材料,其可逆容量在200 mAh/g以上,其高容量特性引起人们的广泛关注。这类材料可以用xLi2MO3.（1-x）LiM＇O2（M为Mn,Ti,Zr之一或任意组合;M＇为Mn,Ni,Co之一或任意组合;0≤x≤1）形式表示。由于其组成与结构的特殊性,这类富锂层状正极材料的充放电机理也不同于其它含锂过渡金属氧化物正极材料。本文介绍富锂层状正极材料的合成、结构与充放电机理,重点介绍近年来通过改性提高其电化学性能方面的研究进展,指出目前富锂材料研究中存在的问题,探讨未来的研究重点。%Electrode materials are important building blocks of lithium ion batteries.The capacity of the anode material is usually more than 300 mAh/g while that of the cathode is still around 150 mAh/g.The capacity of the cathode materials has become a bottleneck to the improvement of the electrochemical performances of lithium ion battery.Li-rich layer-structured Li1＋xA1-xO2（A=Mn,Ni,Co,Ti,Zr,etc.） cathode materials caught the attention of the scientists in the past decade due to high reversible capacity（200 mAh/g or more）.These materials can also be written as xLi2MO3·（1-x）LiM′O2（M=Mn,Ti,Zr;M′=Mn,Ni,Co;0≤x≤1）.In this review,we introduce the synthesis methods,structure and the charge-discharge mechanism of this type of materials.More attention will be paid to the improvement to their electrochemical properties by surface（coating） and bulk（doping） modification.At the end of this review,the problems and prospects of the research on these cathode materials are commented.