Air-Stable Protective Layers for Lithium Anode Achieving Safe Lithium Metal Batteries

摘要

With markedly expansive demand in energy storage devices, rechargeablebatteries will concentrate on achieving the high energy density and adequatesecurity, especially under harsh operating conditions. Considering the highcapacity (3860 mA h g~(?1)) and low electrochemical potential (?3.04 V vs thestandard hydrogen electrode), lithium metal is identified as one of the mostpromising anode materials, which has sparked a research boom. However, theintrinsically high reactivity triggers a repeating fracture/reconstruction processof the solid electrolyte interphase, side reactions with electrolyte and lithiumdendrites, detrimental to the electrochemical performance of lithium metal batteries(LMBs). Even worse, when exposed to air, lithium metal will suffersevere atmospheric corrosion, especially the reaction with moisture, leading togrievous safety hazards. To settle these troubles, constructing air-stable protectivelayers (ASPLs) is an effective solution. In this review, besides the necessityof ASPLs is highlighted, the modified design criteria, focusing on enhancingchemical/mechanical stability and controlling ion flux, are proposed. Correspondingly,current research progress is comprehensively summarized anddiscussed. Finally, the perspectives of developing applicable lithium metalanodes (LMAs) are put forward. This review guides the direction for the practicaluse of LMAs, further pushing the evolution of safe and stable LMBs.