金属锂枝晶生长机制及抑制方法

摘要

金属锂负极以极高的容量(3860 mAh·g-1)和最负的电势(-3.040 V vs标准氢电极)而被称为二次锂电池“圣杯”电极.以金属锂为负极的金属锂电池是极具前景的下一代高比能电池(比如锂硫和锂氧电池等).然而,在锂离子反复沉积和析出过程中,金属锂负极表面容易生长出锂枝晶,并发生粉化,大大降低了电池的利用率,造成安全隐患,缩短电池使用寿命.本综述针对金属锂的枝晶问题开展评述.首先介绍金属锂负极的工作原理和存在的挑战;其次,评述金属锂负极的枝晶生长模型;再次,总结近年来针对抑制金属锂负极枝晶生长的研究进展.最后,总结全文并对金属锂负极的研究进行了展望.该综述尝试总结金属锂负极近些年在理论和技术上的进步,并为金属锂电池的实用化研究提供借鉴.%With the ultra-high capacity (3860 mAh· g-1) and the most negative electrochemical potential (-3.040 V vs the standard hydrogen electrode),lithium metal is regarded as a "Holy Grail" electrode and has received extensive attentions.Therefore,lithium metal based batteries (such as lithium-sulfur and Li-oxygen batteries) are strongly considered as one of the most promising candidates for the next-generation high-energydensity energy storage devices.However,uncontrolled dendritic-lithium growth results in poor cycling efficiency,severe safety concerns,and poor lifespan,which severely prevents the practical applications of Li metal based batteries.This contribution presents a comprehensive overview on the dendrite issues of lithium metal anode.Firstly,the general working principles and technical challenges of lithium metal anode are introduced.Specific attentions are also paid to the mechanistic understandings and quantitative models for the nucleation and growth of dendritic lithium.Based on these theoretical understanding and analysis,the recently proposed methods to suppress dendrite growth of lithium metal anode are summarized.The perspective on the current limitations and future research directions of LMB are presented.The review is with an attempt at summarizing the theoretical and experimental achievements in lithium metal anode and endeavors to realize the practical applications of lithium metal based batteries.