Defect-enriched, nitrogen-doped graphitic carbon microspheres within 3D interconnected super-macropores as efficient oxygen electrocatalysts for breathing Zn-Air battery

Constructing efficient bifunctional oxygen electrocatalyst which integrates highly efficient active sites with desired structures for rapid mass transport is of great importance for designing rechargeable Zn-air battery with high power density and fast charge and discharge performances. Herein, defect-enriched N-doped graphitic carbon microspheres with fully open and 3D interconnected super-macropores are successfully constructed by an elaborate coating-activation synthesis strategy. The resulted novel structures are featured with abundant defects as active sites and bicontinuous structures, i.e., the continuous carbon skeleton and the interconnected super-macropores for fast electron and mass transport, respectively. Our synthesized defect-enriched N-doped graphitic carbon microsphere bifunctional oxygen electrocatalysts display excellent performance. The rechargeable Zn-air batteries exhibit a long time charging-discharging cycles as long as 800 cycles at even 50 mA cm−2. This study provides an attractive guide to improve the bifunctional oxygen catalytic performances and promote the Zn-air battery applications in both electric vehicles and grid energy storage in the future.