Suppression of zinc anode corrosion for printed flexible zinc-air battery

Self-discharge caused by hydrogen evolution reaction (HER) coinciding with corrosion of the zinc anode is a major drawback of printed zinc-air batteries. Thus, this work aims at suppressing self-discharge of flexible printed zinc-air batteries by coating thin layer of aluminum oxide (Al2O3) onto the surface of zinc particles. The Al2O3 coating layer was directly synthesized onto the zinc particles by a low-cost and facile sol-gel method. The Al2O3 coating effectively mitigated HER of the zinc particles, and delayed the corrosion of the zinc anode. Further, the effects of the thickness of Al2O3 layer on corrosion behavior of the zinc anode in 9 M potassium hydroxide as well as performance of the batteries were investigated. With a proper thickness of Al2O3 coating, corrosion of the battery was considerably suppressed without sacrificing the battery performance. (a) Photographic image of the fabricated battery, (b) transmission electron microscopic image of zinc particle coated with Al2O3.