Challenges and strategies for constructing stable aluminum metal anodes in rechargeable aluminum-ion batteries

With the growing market for electric vehicles and the development of renewable energy storage technologies, rechargeable aluminum-ion batteries (RAIBs) have garnered significant interests because of the abundant natural resources, impressive theoretical capacity and inherent safety advantages. Nevertheless, the poor stability of metallic Al anode poses a formidable challenge, stemming from issues such as self-corrosion and dendritic growth in ionic liquid electrolyte, as well as self-corrosion, surface passivation and hydrogen evolution reaction in aqueous electrolyte. This comprehensive review delves into the key scientific challenges faced of Al anode both in non-aqueous and aqueous electrolytes, and subsequently outlines innovative strategies and recent progresses that aimed at stabilizing aluminum metal anodes. In summary and outlook part, we present insightful suggestions and future perspectives for constructing stable aluminum metal anodes, which could propel the development of high-performance RAIBs. Specially, we also concern the controversy about aqueous aluminum-ion batteries and propose some reasonable standards for proving the reversibility of aqueous RAIBs.