Activation and Stabilization Strategies of Aluminum Metal Anode Toward High Performance Aqueous Al Metal Batteries

Aqueous aluminum metal batteries (AAMBs) have garnered significant attention due to the abundant reserves, low cost, high theoretical capacity, and intrinsic safety of aluminum (Al). However, Al³⁺-based energy storage technologies remain in their nascent stages, facing a multitude of challenges. One major issue is the poor thermodynamic stability of the aluminum metal anode in aqueous electrolytes, stemming from self-corrosion, surface passivation, or hydrogen evolution reactions. These parasitic reactions dramatically reduce the reactivity, prevent reversible deposition/dissolution of aluminum, and restrict the electrochemical performance of AAMBs. This review spotlights the critical challenges faced by aluminum metal anodes and aqueous electrolytes. Then, recent progress on activating and stabilizing Al metal anode is summarized and discussed in terms of two aspects, including anode engineering and electrolyte optimization. Ultimately, future designs of high reaction activity of Al metal anode and electrolytes with high reversibility, long lifespan, and high energy density are proposed, which potentially facilitate the development of new generation of Al-based energy storage batteries.