Wood‐Derived Integral Air Electrode for Enhanced Interfacial Electrocatalysis in Rechargeable Zinc–Air Battery

Abstract Zinc–air batteries (ZABs) are promising as energy storage devices owing to their high energy density and the safety of electrolytes. Construction of abundant triple‐phase boundary (TPB) effectively facilitates cathode reactions occurring at TPB. Herein, a wood‐derived integral air electrode containing Co/CoO nanoparticles and nitrogen‐doped carbonized wood (Co/CoO@NWC) is constructed with a dual catalytic function. The potential gap between oxygen reduction and evolution is shortened to 0.77 V. Liquid ZABs using Co/CoO@NWC as cathode exhibit high discharge specific capacity (800 mAh g Zn −1 ), low charge–discharge gap (0.84 V), and long‐term cycling stability (270 h). Co/CoO@NWC also shows distinguished catalytic activity and stability in all‐solid‐state ZABs. The inherent layered porous and pipe structures of wood are well maintained in catalytically active carbon. The different hydrophilicity of carbonized wood and Co/CoO endow abundant TPBs for battery reaction. The Co/CoO located on TPB provides main active sites for oxygen reactions. The inherent pipe structures of wood carbon and the interaction between Co/CoO and NWC effectively prevent nanoparticles from aggregation. The design and preparation of this monolithic electrocatalyst contribute to the broad‐scale application of ZABs and promote the development of next‐generation biomass‐based storage devices.