A rechargeable zinc-air battery based on zinc peroxide chemistry

Rechargeable alkaline zinc-air batteries promise high energy density and safety but suffer from the sluggish 4 electron (e–)/oxygen (O2) chemistry that requires participation of water and from the electrochemical irreversibility originating from parasitic reactions caused by caustic electrolytes and atmospheric carbon dioxide. Here, we report a zinc-O2/zinc peroxide (ZnO2) chemistry that proceeds through a 2e–/O2 process in nonalkaline aqueous electrolytes, which enables highly reversible redox reactions in zinc-air batteries. This ZnO2 chemistry was made possible by a water-poor and zinc ion (Zn2+)–rich inner Helmholtz layer on the air cathode caused by the hydrophobic trifluoromethanesulfonate anions. The nonalkaline zinc-air battery thus constructed not only tolerates stable operations in ambient air but also exhibits substantially better reversibility than its alkaline counterpart.

Source: ScienceNOW - December 31, 2020 Category: Science Authors: Sun, W., Wang, F., Zhang, B., Zhang, M., Küpers, V., Ji, X., Theile, C., Bieker, P., Xu, K., Wang, C., Winter, M. Tags: Chemistry, Materials Science r-articles Source Type: news