Bubble Evolution in Rechargeable Zinc-Air Batteries: Mechanisms, Mitigation Strategies, and Future Prospects

Rechargeable zinc-air batteries (ZABs) are considered among the most promising power sources for portable electronic devices and electric vehicles due to their high energy density, environmental friendliness, and low production costs. However, a major challenge hindering their commercialization is the issue of gas evolution during operation. The electrochemical reactions at both the zinc electrode (hydrogen evolution reaction, HER) and the air electrode (oxygen evolution reaction, OER) result in the formation of gas bubbles. These bubbles reduce the active surface area, increase internal resistance, and disrupt the uniformity of electrochemical reactions, ultimately causing a decrease in battery performance or even failure. This work summarizes the mechanisms behind gas evolution in ZABs and explores various strategies to mitigate bubble formation, including optimizing electrode materials, pulse strategies, and structure designs. Finally, we discuss approaches to suppress gas evolution reactions and outline future research directions to enhance the performance of ZABs.