Flexible Metal-gas Batteries: A Potential Option for the Next-generation Power Accessories of Wearable Electronics

Flexible metal-gas batteries are becoming more and more attractive to wearable electronics in recent years due to their large theoretical energy density and superior adaptability to irregular geometric surfaces, like human body. As the continuous improvement of design strategies and assembly technologies, various advanced flexible metal-gas batteries have been attempted to fabricate. Despite of these efforts, how to synchronously integrate high-flexibility, safety, comfortability and high-performance into flexible metal-gas batteries with specifically-functionalized configurations still remains a big challenge. To solve these dilemmas, re-design on cathode catalysts, gel polymer electrolyte, and battery configuration/components have been focused. In this paper, we make an overview on recent technical advances together with major dilemmas facing current flexible metal-gas batteries, highlighting how flexible cathodes and gel polymer electrolyte with various structures and components affect the electrochemical performance and functionality of flexible metal-gas batteries. Flexible Zn-air, Li-O2/air and Li-CO2 batteries are mainly exemplified to elucidate their great potential. Finally, based on our consideration, unsolved technical hurdles and future research perspectives of flexible metal-gas batteries for wearable electronics are given.