Strategies for Realizing Rechargeable High Volumetric Energy Density Conversion-Based Aluminum-Sulfur Batteries

Aluminum-sulfur batteries (ASBs) are deemed to be alternatives to meet the increasing demands for energy storage due to their high theoretical capacity, high safety, low cost, and the rich abundances of Al and S. However, the challenging problems including sluggish conversion kinetics, inferior electrolyte compatibility, and potential dendrite formation are still remained. This review comprehensively focuses on summarizing the specific strategies from polysulfide shuttling inhibition to form smooth anodic Al activation/deposition. Especially, innovations in cathodic side for achieving electrochemical kinetic modulations, electrolyte optimizations, and anodic interface mediations are discussed. Upon detailed elaborating the formation process, influencing factors, and their interactions in the Al-S electrochemistry, a comprehensive summary of their causative mechanisms and the corresponding strategies are provided, including optimization of electrolytes, innovative in situ detections, and precise electrocatalytic strategies. Based on such a systematic understanding in the Al-S electrochemistry, the possible electrochemical reaction mechanism is deciphered more clearly and enlightened practical strategies on the future development of stable ASBs. Furthermore, future opportunities and directions of high-performance conversion-based Al-S batteries for large-scale energy storage applications are highlighted.