Aluminum-air batteries: current advances and promises with future directions

Owing to their attractive energy density of about 8.1 kW h kg^-1 and specific capacity of about 2.9 A h g^-1, aluminum-air (Al-air) batteries have become the focus of research. Al-air batteries offer significant advantages in terms of high energy and power density, which can be applied in electric vehicles; however, there are limitations in their design and aluminum corrosion is a main bottleneck. Herein, we aim to provide a detailed overview of Al-air batteries and their reaction mechanism and electrochemical characteristics. This review emphasizes each component/sub-component including the anode, electrolyte, and air cathode together with strategies to modify the electrolyte, air-cathode, and even anode for enhanced performance. The latest advancements focusing on the specific design of Al-air batteries and their rechargeability characteristics are discussed. Finally, the constraints and prospects of their use in mobility applications are also covered in depth. Thus, the present review may pave the way for researchers and developers working in energy storage solutions to look beyond lithium/sodium ion-based storage solutions.