Extreme Fast Charging of Lithium Metal Batteries Enabled by a Molten‐Salt‐Derived Nanocrystal Interphase

Abstract The extreme fast charging performance of lithium metal batteries (LMBs) with a long life is an important focus in the development of next‐generation battery technologies. The friable solid electrolyte interphase and dendritic lithium growth are major problems. The formation of an inorganic nanocrystal‐dominant interphase produced by preimmersing the Li in molten lithium bis(fluorosulfonyl)imide that suppresses the overgrowth of the usual interphase is reported. Its high surface modulus combined with fast Li + diffusivity enables a reversible dendrite‐proof deposition under ultrahigh‐rate conditions. It gives a record‐breaking cumulative plating/stripping capacity of >240 000 mAh cm −2 at 30 mA cm −2 @30 mAh cm −2 for a symmetric cell and an extreme fast charging performance at 6 C for 500 cycles for a Li||LiCoO 2 full cell with a high‐areal‐capacity, thus expanding the use of LMBs to high‐loading and power‐intensive scenarios. Its usability both in roll‐to‐roll production and in different electrolytes indicating the scalable and industrial potential of this process for high‐performance LMBs.