A Review of Metal–Air Fuel Cells: Progress, Challenges, and Perspectives

Metal–air fuel cells (MAFCs) have gained considerable attention as next-generation energy devices due to their high energy density, lightweight structure, and potential to support sustainable energy systems. These cells offer promising alternatives to traditional batteries and fuel cells, especially for applications in electric vehicles and large-scale energy storage, aligning with the global shift toward cleaner and more renewable energy sources. A lot of improvements have been made in creating better materials for the electrodes, electrolytes, and designs of the cells, which have enhanced the performance of different kinds of MAFCs, like zinc–air, lithium–air, and aluminum–air; however, critical challenges like limited rechargeability, electrode degradation, catalyst instability, and electrolyte-related issues continue to hinder their widespread commercial adoption. These persistent obstacles highlight an important research gap in achieving cost-effective, durable, and scalable MAFCs. This review synthesizes recent developments and discusses the key technical barriers facing MAFCs, emphasizing the balance between high energy density and long-term stability. It also explores emerging strategies aimed at overcoming these challenges to unlock the full potential of metal–air systems. The information in this review is timely and necessary for moving forward with sustainable energy storage solutions, which will help the United Nations reach its Sustainable Development Goal 7 (affordable and clean energy). By identifying current limitations and future research directions, this paper aims to accelerate the development and commercialization of MAFCs, supporting the global transition toward a low-carbon and energy-secure future.