钴酸锂正极材料高电压下衰退机制及改性策略

Degradation Mechanism and Modification Strategy of Lithium Cobalt Cathode Material under High Voltage

钴酸锂具有高压实密度、高能量密度的优点,是消费类电子产品用锂离子电池的主要正极材料。为了满足消费类电子产品对能量密度需求的提升,需进一步提高LiCoO_(2)电池的上截止电压,以实现电池更高的能量密度。然而,当钴酸锂充电到高电压(4.2 V)时,包括表面副反应、相转变引起的材料结构衰退出现,导致容量、效率和循环寿命快速衰减。本文综述了LiCoO_(2)高电压下晶体结构衰退及表界面失效的机制,并对解决衰退的包覆及掺杂改性策略进行了简要概述。

Lithium cobalalt oxide has the advantages of high-pressure real density and high energy density,and is the main cathode material of lithium-ion batteries for consumer electronics equipment.In order to meet the demand of the improvement of the energy density for consumer electronics,the upper cut-off voltage of the LiCoO_(2) battery should be further improved to achieve a higher energy density.However,when LiCoO_(2) is charged to a high voltage(4.2 V),the material structural degradation caused by the surface side reaction,phase transition occurs,resulting in a rapid attenuation of capacity,efficiency,and cycle life.This paper summarizes the mechanism of crystal structure decay and surface interface failure for LiCoO+at high voltage,and briefly summarizes the coating and doping modification strategies used to solve the recession.