Improving Cycle Life of Zinc–Air Batteries with Calcium Ion Additive in Electrolyte or Separator

Abstract

The electrolyte carbonation and the resulting air electrode plugging are the primary factors limiting the cycle life of aqueous alkaline zinc–air batteries (ZABs). In this work, calcium ion (Ca2+) additives were introduced into the electrolyte and the separator to resolve the above issues. Galvanostatic charge–discharge cycle tests were carried out to verify the effect of Ca2+ on electrolyte carbonation. With the modified electrolyte and separator, the cycle life of ZABs was improved by 22.2% and 24.7%, respectively. Ca2+ was introduced into the ZAB system to preferentially react with CO32− rather than K+ and then precipitated granular CaCO3 prior to K2CO3, which was deposited on the surface of the Zn anode and air cathode to form a flower-like CaCO3 layer, thereby prolonging its cycle life.