Multifunctional artificial solid electrolyte interphase layer for lithium metal anode in carbonate electrolyte

Abstract

The practical application of Li metal in rechargeable batteries is seriously hindered by its irregular dendrite growth resulting in inferior cycling efficiency and poor safety. Herein, a multifunctional artificial solid electrolyte interphase (SEI) layer is constructed on lithium surface via chemical reactions between lithium metals and allyl glycidyl ether (AGE). The protected layer is mainly composed of cross-linked polyethylene chains and polyethylene oxide moieties, which significantly improved the cycling performance of Li|Li symmetric cells and high voltage Li|NCM523 (4.5 V) cells in the electrolyte of 1 M LiPF6 in EC/DMC/EMC (1:1:1, by wt.). Electrochemical impedance spectroscopy (EIS) and scanning electron microscope (SEM) measurements confirm that the protected layer could reduce the morphology changes and suppress the parasitic reactions of lithium anodes effectively. A probable mechanism based on polymerization and cross-linking reactions of AGE is proposed for the formation of artificial SEI layer. These results demonstrated that the multifunctional artificial solid electrolyte interphase (SEI) layer have considerable potential application to protect lithium metal anode.