Atmospheric-Pressure Operation of All-Solid-State Batteries Enabled by Halide Solid Electrolyte

All-solid-state batteries aim to provide increased safety and higher energy density for next-generation energy storage. However, challenges remain due to volume changes and inadequate contact between the cathode active material and solid electrolyte particles, leading to poor cyclability. This study investigates the use of the halide-based Li3YBr2Cl4 solid electrolyte to address these issues. Through experimental evaluations with the LiNi0.6Mn0.2Co0.2O2 cathode material, we demonstrate reliable operation down to 0.1 MPa against a LiIn alloy and 0.2 MPa against a Li metal anode, with limited capacity loss. Furthermore, we observe that pressures below 5 MPa do not hinder the rate capabilities, retaining 70% of the C/20 capacity even under 1C discharge rate. These findings underscore the potential of halide-based ASSBs for practical applications and Li metal integration, providing insights for developing reliable low-pressure all-solid-state battery systems.