A high-entropy multicationic substituted Li₁₀GeP₂S₁₂ solid electrolyte enabling stable all-solid-state batteries

Solid-state batteries are promising for advanced electronic and energy systems owing to their intrinsic safety and high energy density. However, achieving superionic solid electrolytes with high ionic conductivity and electrochemical stability under high-voltage conditions remains a critical challenge. Recently, multicomponent, or high-entropy, sulfide solid electrolytes have attracted considerable attention owing to their promising material properties. Here, we report a high-entropy Li₁₀GeP₂S₁₂-based sulfide solid electrolyte that delivers a high ionic conductivity of 13.24 mS cm⁻¹ at room temperature and retains 3.10 mS cm⁻¹ at 0 °C. When paired with an LiNbO₃-coated NCM721 cathode and a LiIn alloy anode, full cells cycled between 2.0 and 4.2 V deliver an initial discharge capacity of 130 mAh g⁻¹ at 1C and retain 80 mAh g⁻¹ after 100 cycles. Our results show that tuning atomic configurational entropy yields favorable and stable microstructures. Multi-cation substitution boosts lithium ion hopping transport, lowers the migration barrier, and enhances electrochemical stability. Our demonstration provides a paradigm for improving the electrochemical performance of solid electrolyte materials through entropy engineering.