What matters in engineering next-generation rechargeable Zn-air batteries?

Rechargeable Zn-air batteries are considered the next-generation energy storage devices for renewable energy due to their high energy density, high safety, low cost, and eco-friendliness. However, rechargeable Zn-air batteries are still far from practical applications for existing many issues, including low energy efficiency, inferior cycling stability, poor depth of discharge, etc. Therefore, understanding the relationship between issues of each component and performance is requested to construct practical rechargeable Zn-air batteries. Herein, we provide an in-depth discussion about the challenge of engineering future rechargeable Zn-air batteries. First, the performance evaluation index and the configuration of rechargeable Zn-air batteries are first introduced. Then we introduce the issues of each component in rechargeable Zn-air batteries and the corresponding solution based on recently reported works. Simultaneously, the impact of each component on performance is discussed. Finally, some personal perspectives, including key component design, performance evaluation index, test conditions, etc., on future development, are presented. This review may afford a direction for the future development of rechargeable Zn-air batteries and inspires more research work under industrial testing conditions.