Amide-Based Interface Layer with High Toughness In Situ Building on the Li Metal Anode

Lithium metal is considered to be the ultimate anode for lithium-ion batteries (LIBs) because of its ultrahigh capacity and lowest electrochemical potential. However, the high reactivity of the lithium metal triggers continuous electrolyte consumption and dendrite growth, resulting in short cycle lifetime and serious safety issues. Massive efforts have been made to stabilize the surface of the lithium metal anode. Here, we propose an amide-based passivation layer to serve as an electrochemically stable and highly tough SEI on the lithium metal anode by in situ generation. The SEI layer presents a high elasticity modulus of 10 GPa and enables stable cycling in 2500 h. Furthermore, based on our strategy, the Li/LiFePO₄ cell with a cathode loading of ∼19 mg cm^-2 exhibits a long lifespan of 400 cycles. Our approach establishes a meaningful guideline for building a highly strong electrolyte/electrode interface in high-energy density lithium metal batteries.