Advanced High-Entropy Halide Solid Electrolytes Enabling High-Voltage, Long-Cycling All-Solid-State Batteries

Stable solid electrolytes are essential for advancing the safety and energy density of lithium batteries, especially in high-voltage applications. In this study, we designed an innovative high-entropy chloride solid electrolyte (HE-5, Li_2.2In_0.2Sc_0.2Zr_0.2Hf_0.2Ta_0.2Cl₆), using multielement doping to optimize both ionic conductivity and high-voltage stability. The high-entropy disordered lattice structure facilitates lithium-ion mobility, achieving an ionic conductivity of 4.69 mS cm^-1 at 30 °C and an activation energy of 0.300 eV. Integration of HE-5 into all-solid-state batteries (ASSBs) with NCM83 cathodes and a Li-In anode enables outstanding electrochemical performance, sustaining 70% capacity retention over 1600 cycles at a 4 C rate. Moreover, the high configurational entropy stabilizes the electrolyte's structure at elevated voltages, enabling stable operation at 5.0 V without significant degradation. Our work presents the dual advantages of high-entropy engineering in boosting high ionic conductivity and voltage stability, providing a broad roadmap for next-generation energy-dense ASSBs.