Materials Design for Rechargeable Metal-Air Batteries

Progress and PotentialMetal-air batteries, powered by metal oxidation and oxygen reduction, have been intensely focused upon as promising next-generation high-energy batteries. However, the practical application of rechargeable metal-air batteries faces challenges, such as unsatisfying power density, round-trip efficiency, and Coulombic efficiency. Rational material design of the air electrode, metal electrode, electrolyte, and separator is highly desired to address these issues. This Review presents recent advances on the material design toward high-performance rechargeable metal-air batteries. Targets and principles for the material design of each part of metal-air batteries are highlighted. For future investigations, greater emphasis should be placed on achieving stable and reversible charge-discharge cycles to accelerate the development of truly rechargeable metal-air batteries.SummaryIn 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.Graphical abstract