Electrodeposition-guided pre-passivation of Li-metal anode to enable long stable cycling of practical Li-metal batteries

Abstract

Ultrathin, large-area Li metal anodes (LMAs) are essential for high-energy Li-metal batteries (LMBs). However, most commercially manufactured LMAs (M-Li) form a native passivation layer (NPL) during manufacturing. Intrinsically non-uniform NPL can initiate sporadic Li dendrite growth and the chemical/structural deterioration of LMAs. This study presents an electrochemical pre-passivation method to build an electrolyte-derived native layer (ENL) using electrodeposited Li (ED-Li). Using localized high-concentration electrolytes and post-calendering, ED-Li can build a Li2CO3-less, fluorinated ENL and decrease the surface roughness. Herein, ED-Li facilitates Li nucleation during earlier Li plating owing to the electrolyte-compatible ENL, and alleviates pitting during subsequent Li stripping, thereby mitigating LMA swelling. ED-Li improves the cycling stability of Li||NMC622 cells to outperform M-Li, which is further validated using different electrolytes under practical conditions, demonstrating its potential for use as the starting LMA in post-treatment approaches, such as protective layer coating and electrolyte-driven passivation.