Sm/O Co-doped zirconium chloride electrolytes for solid-state Li batteries

The development of solid-state batteries with high safety and energy density is critical for next-generation storage. However, conventional halide electrolytes like Li₂ZrCl₆ suffer from low room-temperature ionic conductivity. We propose a synergistic Sm³⁺ and O^2- co-doping strategy and synthesize a novel oxychloride LSZCO via ball milling. Sm³⁺ expands Li⁺ migration channels, while O^2- induces local disorder to build an isotropic fast-ion network. The optimized LSZCO-1.250 achieves 1.204 mS cm^-1 conductivity, 0.296 eV activation energy. Assembled all-solid-state batteries with Li₆PS₅Cl buffer, Li-In anode, and NCM811@LNO or LCO cathodes show at 0.1 A g^-1 an initial discharge capacity of 171 mAh g^-1 for NCM811, with 50.3% retention after 250 cycles, and 86.2% retention after 70 cycles for LCO. Rate tests confirm capacity recovery after high currents, indicating good interfacial stability. This work provides an effective doping strategy for high-conductivity oxyhalide electrolytes.