Materials Design for Rechargeable Metal-Air Batteries

In consideration of the growing problems regarding environment and energy, the development of clean and renewable electrochemical energy-storage devices has attracted much attention. Metal-air batteries with ultra-high energy density, including but not limited to Zn-air and Li-air batteries, have shown great potential for future large-scale applications. In this Review, fundamentals on the electrode reactions of metal-air batteries are firstly introduced. Current issues on achieving applicable discharge properties and rechargeability are then presented. In the following sections, the material design strategies of the air electrode, metal electrode, electrolyte, and separator to overcome these issues are summarized. The most widely investigated Zn-air and Li-air batteries are overviewed in detail, while other types of metal-air batteries including Al-air, Mg-air, and Na-air batteries are briefly discussed. Finally, summary and perspectives on the future development of metal-air batteries toward practical applications are provided.