A self-smoothing Li-metal anode enabled via a hybrid interface film

Abstract

Li-metal is an ideal anode for high energy batteries, but uncontrollable dendrite growth restricts its practical application in rechargeable high energy batteries. To address this issue, we propose a novel strategy by constructing a hybrid interface film on Li metal. The film is formed by simply dropping a LiTFSI- and AgNO₃-containing solution on Li metal, and it mainly consists of Ag_xLi_y, Ag₂S, LiF, and Li₂O. These hybrid compositions provide the Li anode with a lithiophilic surface, low Li depositing/stripping overpotential and protective interface film, yielding a ‘self-spreading’ deposition behavior of Li and excellent cycling stability of Li-metal batteries. When the Li anode modified with this hybrid interface film is matched with an LFP cathode, the initial coulombic efficiency of the battery cycled at 1C at 60 °C improves from 80% to 95%, while when matched with an NCA cathode, the capacity retention of the battery improves from 36% to 73% after 500 cycles at 1C at −10 °C.