Integrated Bifunctional Oxygen Electrodes for Flexible Zinc–Air Batteries: From Electrode Designing to Wearable Energy Storage

Abstract The strong propulsion stem from flexible/wearable electronics has greatly stimulated the development of miniaturized and high‐performance rechargeable batteries with adaptable shape. Flexible zinc–air batteries (FZABs), which exhibit high theoretical energy density (1218 Wh kg −1 ), low cost, environmental benignancy, and admirable operational safety, have been widely recognized as one of the promising portable powers to serve future wearable electronics for ubiquitous application. During the past five years, the energy/power density and cycling stability of FZABs have gained significant improvement largely due to the rational construction of high‐efficiency bifunctional air electrodes. Herein, the recent progress of integrated binder‐free bifunctional oxygen electrodes is overviewed via elaborate in situ preparation and interface engineering for FZABs. In particular, fiber/cable‐type ZABs with unrivaled omnidirectional‐flexibility and unique knittability are highlighted in virtue of their enormous potential to realize wearable batteries and smart fabrics. From a practical point of view, the recently proposed rechargeable ZABs for integrated/hybridized devices or self‐powered energy systems are reviewed. Finally, the remained challenges and some insightful directions for the future development of high‐performance FZABs are illustrated in the pursuit of cost‐efficient portable powers and multifunctional flexible/wearable electronic devices.