Hollow CoOX nanoparticle-embedded N-doped porous carbon as an efficient oxygen electrocatalyst for rechargeable zinc–air batteries

Abstract

Optimization of bifunctional oxygen catalysts plays an important role in achieving rechargeable zinc–air batteries (ZABs) with good cycling life and large power/energy density. Herein, we provide a simple yet efficient synthetic approach to synthesize hollow cobalt oxide nanoparticles embedded in three-dimensional (3D) porous carbon hybrids via a spray-drying method followed by a carbonization process. Regulation of the porosity and defects of the carbon skeleton leads to the exposure of abundant cobalt oxide nanoparticles, thus synergistically improving the bifunctional electrocatalytic activity for oxygen reduction and evolution reactions. The interconnected 3D porous architecture further facilitates mass/charge transfer. Consequently, the as-assembled ZABs exhibited high power density and good cycling durability with both aqueous and solid-state electrolytes.