Stable Lithium Anodes Enabled by the Hardening and High Li+ Flux Interlayer

The commercial use of lithium metal batteries is greatly limited by dendrite formation and slow Li⁺ transport at the anode–electrolyte interface. Herein, the constructed high-modulus polymer interlayer suppressed the Li dendrite formation, leading to dense deposition and enhanced Li⁺ transport. Meanwhile, this formed robust organic solid–electrolyte interphase inhibited the side reactions occurring at the anode–electrolyte interface while promoting a high Li⁺ flux. By constructing the polymer interlayer, the Li@P3DDT||Li@P3DDT symmetric cells demonstrated an impressive stability lifespan of over 3400 h at 1 mA/cm² and 1 mAh/cm². The LFP||Li@P3DDT full cells exhibit a remarkable capacity retention of 85.0% over 300 cycles at 4 C. Furthermore, the 50 μm Li@P3DDT||LiCoO₂ pouch cell with 380 Wh kg^–1 maintained over 99.9% retention of capacity over 60 cycles at 0.5 C. The research paves the way for the advancement of stable lithium anodes.