In situ forming LiF nanodecorated electrolyte/electrode interfaces for stable all-solid-state batteries

The unstable solid electrolyte/electrode interface with dendrite growth and resistance increase significantly reduces the safety and efficiency of all-solid-state batteries. Here, we propose an ‘in situ LiF nanodecoration’ approach to address this issue. By uniform dispersion of ultrafine LiF nanoparticles in amorphous Li₂B₁₂H₁₂ matrix that is in situ formed via a solid-state reaction, the resulting composite as electrolyte exhibits favorable Li-ion conductivity (5 × 10⁻⁴ S cm⁻¹) with low electronic conductivity (9 × 10⁻¹⁰ S cm⁻¹) at 75 °C. More importantly, this composite electrolyte shows superior electrode compatibility by forming stable electrolyte/electrode interfaces, as demonstrated by high Li dendrite suppression capability (critical current density: 3.6 mA cm⁻²) and small interfacial resistance (area specific resistance after 10 cycles: 746 Ω cm²) at 75 °C, which further enables the stable cycling of Li–LiFePO₄ all-solid-state batteries. This work paves a way for using in- situ nanodecoration chemistry for the design of safe and high efficiency all-solid-state batteries.