Fast-charging capability of graphite-based lithium-ion batteries enabled by Li3P-based crystalline solid–electrolyte interphase

Abstract

Li+ desolvation in electrolytes and diffusion at the solid–electrolyte interphase (SEI) are two determining steps that restrict the fast charging of graphite-based lithium-ion batteries. Here we show that the low-solvent-coordination Li+ solvation structure could be induced near the inner Helmholtz plane on inorganic species. Specifically, Li3P could enable a lower Li+ desolvation barrier and faster Li+ diffusion capability through the SEI in comparison to the regular SEI components. We construct an ultrathin S-bridged phosphorus layer on a graphite surface, which in situ converts to crystalline Li3P-based SEI with high ionic conductivity. Our pouch cells with such a graphite anode show 10 min and 6 min (6C and 10C) charging for 91.2% and 80% of the capacity, respectively, as well as 82.9% capacity retention for over 2,000 cycles at a 6C charging rate. Our work reveals the importance of the SEI component and structure regulation for fast-charging LIBs. State-of-the-art graphite anodes cannot meet the extremely fast charging requirements of ever-demanding markets. Here the researchers develop a Li3P-based solid–electrolyte interphase, enabling fast (down to 6 min) charging of graphite-based Li-ion batteries.