Unveiling the power of sulfide solid electrolytes for next-generation all-solid-state lithium batteries

Sulfide solid electrolytes are promising materials for next-generation all-solid-state lithium batteries due to their high ionic conductivity, mechanical properties, and compatibility with advanced electrodes like lithium metal. Recent advancements have focused on optimizing synthesis techniques, including both solid-phase and liquid-phase methods, alongside strategic doping modifications that enhance ionic conductivity and improve chemical stability. Despite these improvements, challenges remain, particularly in stabilizing interfaces between sulfide solid electrolytes and electrodes, as chemical reactivity leads to resistive layers and reduced battery performance. Efforts to address these challenges involve protective coatings, surface engineering, and advanced structural modifications. Additionally, sulfide solid electrolytes face environmental sensitivity, with exposure to air and moisture leading to degradation. To counter this, strategies such as hybrid electrolyte systems and surface treatments are being investigated to ensure long-term stability under various conditions. This review summarizes recent developments in sulfide solid electrolytes synthesis, doping modification, and interface engineering, while outlining future directions needed for the successful commercialization of all-solid-state lithium batteries, positioning sulfide-based electrolytes as key components for advancing battery safety, efficiency, and energy density.