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. We report the formation of an inorganic nanocrystal-dominant interphase produced by pre-immersing the Li in molten lithium bis(fluorosulfonyl)imide that suppresses the overgrowth of the usual interphase. 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 indicates its scalable and industrial potential.