Spinel-Type Li ₂ MnCl ₄ Solid Electrolyte for All-Solid-State Batteries

Spinel-type halides are promising solid-state electrolytes with good interfacial compatibility and low cost. Herein, we report Li 2 MnCl 4 electrolytes with Li/Mn ratio tuning in Li 2–2 x Mn 1+ x Cl 4 ( x = 0 – 0.3), lithium vacancies accelerate Li + diffusion and spinel lattice reconstruction forms continuous ion transport channels, yielding a room-temperature ionic conductivity of 0.12 mS·cm –1 . Li 1.7 Mn 1.15 Cl 4 -based all-solid-state batteries show high cycling stability with average Coulombic efficiency >99%. This work demonstrates Li 2 MnCl 4 as a promising halide electrolyte for all-solid-state batteries.