A Superior Li 2 CO 3 -Derived Li 2 ZrOCl 4 Electrolyte Enabling High-Performance All-Solid-State Lithium Batteries

All-solid-state lithium batteries (ASSLBs) are promising next-generation energy storage systems due to their superior safety. While low-cost Li 2 ZrCl 6 is a candidate halide solid electrolyte, its ionic conductivity remains modest (0.33 mS cm –1 ). Herein, we report a highly conductive amorphous halide solid electrolyte (1.64 mS cm –1 ), synthesized using high-energy Li 2 CO 3 as a precursor to replace conventional Li 2 O. This approach enhances reaction efficiency and reduces cost. The resulting Li 2 ZrOCl 4 (LZOC) structure facilitates Li + migration, as confirmed by experimental and theoretical results. ASSLBs incorporating the LZOC electrolyte with a Li–In anode and uncoated LiCoO 2 (LCO) cathode demonstrate excellent cycling stability (97% capacity retention after 200 cycles at 1 C) and high-rate capability (over 70 mAh g –1 at 2 C). This work establishes the use of low-cost Li 2 CO 3 as a practical strategy for developing high-performance, cost-effective ASSLBs.