Influence of ZnO precipitation on the cycling stability of rechargeable Zn-air batteries

In this work, the effect of ZnO precipitation on the electrochemical cycling stability of Zn-air batteries was systematically investigated. The results suggest that sustained electrical rechargeability can be achieved by simply appropriately choosing the amount of Zn metal anode, such that the amount of zincate ions released into the electrolyte upon full discharge of the anode is below the supersaturated solubility limit. For example, there was almost no capacity fading up to 50 cycles when the anode was designed such that the amount of zincate ions released into the electrolyte was a bit less than the chemical solubility limit of ZnO in KOH solution. Despite its limited energy density, the results presented in this study provide an important direction to the future work on electrically rechargeable Zn-air batteries.