In-situ polymerized carbonate induced by Li-Ga alloy as novel artificial interphase on Li metal anode

Abstract

Li metal is considered an ideal anode material because of its high theoretical capacity and low electrode potential. However, the practical usage of Li metal as an anode is severely limited because of inevitable parasitic side reactions with electrolyte and dendrites formation. At present, single-component artificial solid electrolyte interphase cannot simultaneously meet the multiple functions of promoting ion conduction, guiding lithium ion deposition, inhibiting dendrite growth, and reducing interface side reactions. Therefore, multi-component design on Li metal surface is widely investigated to achieve long-term cycling. Herein, we report a Li2Ga-carbonate polymer interphase layer to solve volume changes, Li dendrites formation and side-reactions. As a result, the Li symmetric cell can be stabilized at 3.0 mA/cm2 in carbonate electrolyte with limited volume of 20 µL. Coupled with 13.6 mg/cm2 (loading of 2 mAh/cm2) LiFePO4 cathode, discharge capacity retains at 90% for over 150 cycles under limited electrolyte conditions. With such an alloy-polymer interphase layer, higher energy density Li metal batteries become prominent in the near future.