High Young’s Modulus Li_6.4La₃Zr_1.4Ta_0.6O₁₂-Based Solid Electrolyte Interphase Regulating Lithium Deposition for Dendrite-Free Lithium Metal Anode

Artificial solid electrolyte interphase (SEI) layers have been widely regarded as an effective protection for lithium (Li) metal anodes. In this work, an artificial SEI film consisting of dense Li_6.4La₃Zr_1.4Ta_0.6O₁₂ (LLZTO) nanoparticles and polymerized styrene butadiene rubber is designed, which has good mechanical and chemical stability to effectively prevent Li anode corrosion by the electrolyte. The LLZTO-based SEI film can not only guide Li to uniformly deposit at the interface but also accelerate the electrochemical reaction kinetics due to its high Li⁺ conductivity. In particular, the high Young’s modulus of the LLZTO-based SEI will regulate e^- distribution in the continuous Li plating/stripping process and achieve uniform deposition of Li. As a consequence, the Li anode with LLZTO-based SEI (Li@LLZTO) enables symmetric cells to demonstrate a stable overpotential of 25 mV for 600 h at a current density of 1 mA cm^-2 for 1 mA h cm^-2. The Li@LLZTO||LFP (LiFePO₄) full cell exhibits a capacity of 106 mA h g^-1 after 800 cycles at 5 C with retention as high as 90%. Our strategy here suggests that the artificial SEI with high Young’s modulus effectively inhibits the formation of Li dendrites and provides some guidance for the design of higher performance Li metal batteries.