Aluminum Fuel Cells: Tackling Challenges and Unlocking Commercial Potentials

Ongoing global efforts toward sustainable energy storage and conversion have highlighted critical limitations of existing technologies, such as the infrastructure challenges of hydrogen fuel cells (HFCs) and the carbon emissions from diesel generators (DGs). Aluminum fuel cells (AFCs) have emerged as a promising alternative that integrates energy conversion with circular economy principles. This review provides a comprehensive assessment about AFCs, covering the development of key materials including Al anodes, electrolytes, and air cathodes, the electrolytes lifecycle management and the closed-loop regeneration of Al from discharge by-products, and the comparisons in system-level with HFCs and DGs. Particular emphasis is expressed on the back-end recycling of electrolytes and the conversion of Al(OH)₃ back to metallic Al using renewable electricity, thereby closing the material cycle and integrating AFCs with the primary Al industry. From this comprehensive perspective, Al metal can be elevated from a structural material to a recyclable energy carrier. A quantitative benchmarking framework against practical performance targets of anode utilization ≥99%, cathode lifetime ≥2000 h, and system-level energy density ≥500 Wh kg-¹ is proposed. Finally, key challenges and future research directions are outlined, positioning AFCs as a transformative technology for long-duration energy storage, off-grid power, and sustainable transportation.