Cubic hollow porous carbon with defective-edge Fe-N4 single-atom sites for high-performance Zn-air batteries

Regulating the local coordination of Fe active center can further improve the oxygen reduction reaction (ORR) performance of Fe-N-C catalyst to meet the practical application requirements of zinc-air batteries (ZABs). Herein, carbon vacancies modified hollow porous catalysts (C-FeZ8@PDA-950) are constructed by microenvironment modulation, achieving the efficient utilization of active sites and optimization of electronic structure. Density functional theory (DFT) calculations confirm that the defective-edge Fe-N4 sites can weaken the adsorption free energy of OH*, and hinder the dissolution of Fe center, significantly accelerating the ORR process for ZABs. The rechargeable liquid ZABs equipped with C-FeZ8@PDA-950 display high specific capacity (819.95 mAh gZn−1) and excellent long-cycling life (over 500 h). Furthermore, the relevant flexible all-solid-state ZABs also display outstanding folding performance under various bending angles. This work will provide insights into optimizing the electronic structure to improve electrocatalytic performance in the energy conversion and storage area.