A Comprehensive Review and Future Prospects of Aluminum-Sulfur Batteries: From Material Design to Practical Challenges.

Aluminum-sulfur (Al-S) batteries are promising next-generation energy storage systems owing to the high abundance, low cost, and multi-electron redox capability of Al, combined with the high theoretical capacity and environmental friendliness of S. This review systematically compares the dual electrochemical mechanisms based on S reduction (S0/S2-) and S oxidation (S0/S4+), highlighting their distinct advantages in energy density and safety. Key strategies for cathode design-including carbon-based, anchoring-functional, and catalytic-functional hosts-are discussed, alongside electrolyte engineering using ionic liquids, deep eutectic solvents, inorganic molten salts, and aqueous systems. Recent advances in dendrite suppression, anode protective layers, and functional separators are also summarized. A central challenge identified is the sluggish Al3+ solvation/desolvation kinetics, which limits rate capability and low-temperature performance. The application of in situ/operando characterization techniques (XANES, Raman, UV-vis) to unravel complex reaction pathways is emphasized. By integrating multidisciplinary innovations, this review provides a comprehensive perspective and a phased commercialization roadmap, aiming to accelerate the transition of Al-S batteries from laboratory research to practical green energy storage.