Toward Affordable All‐Solid‐State Lithium Batteries: A Novel Li ₂ S‐Free Synthesis for High‐Performance Sulfide Electrolytes with $16.85/Kg Low Cost

ABSTRACT 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 Li ₂ S 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 Li ₂ S with low‐cost precursors (LiH, S, and Li ₂ O), 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 _5.5 PS ₃ O _1.5 Cl _1.5 and the origin of its high ionic conductivity. Moreover, LiNi _0.83 Co _0.12 Mn _0.05 O ₂ (NCM ₈₃ )/Li _5.5 PS ₃ O _1.5 Cl _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.