Toward Affordable All-Solid-State Lithium Batteries: A Novel Li₂S-Free Synthesis for High-Performance Sulfide...

Sulfide solid-state electrolytes (SEs) have emerged as promising electrolyte candidates for all-solid-state lithium batteries (ASSLBs) due to their high ionic conductivity and excellent processability. However, the commercialization of sulfide SEs is hindered by the high cost of the essential Li₂S raw material, making it difficult to strike a balance between high ionic conductivity and economic viability. In this study, we present a cost-effective synthetic approach based on anionic chemistry design to achieve both high ionic conductivity (2.53 mS cm^-1) and low cost ($16.85/kg) for sulfide SSE. By replacing the conventional Li₂S with low-cost precursors (LiH, S, and Li₂O), the oxygen-substituted argyrodite SE is synthesized, while precisely engineering anionic lattice to effectively regulate lithium-ion transport dynamics. X-ray diffraction (XRD) Rietveld refinement and density functional theory (DFT) calculations reveal the crystal structure of the prepared Li_5.5PS₃O_1.5Cl_1.5 and the origin of its high ionic conductivity. Moreover, LiNi_0.83Co_0.12Mn_0.05O₂(NCM₈₃)/Li_5.5PS₃O_1.5Cl_1.5/Li ASSLB delivers more than 1000 cycles. Even under demanding conditions with a high active material loading of 10.7 mg cm^-2, the ASSLBs exhibit satisfactory electrochemical performance over 100 cycles. This strategy presents a novel and effective approach for preparing cost-effective and high-conductive sulfide SEs toward affordable ASSLBs.