A channel-confined strategy for synthesizing CoN-CoO_x/C as efficient oxygen reduction electrocatalyst for advanced zinc-air batteries

Designing hybrid transition metal compounds with optimized electronic structure and firmly dispersing them on a matrix to avoid aggregation and shedding is of great significance for achieving high electrocatalytic performances. Herein, an adsorption-complexation-calcination strategy based on channel confining effect is explored to obtain CoN-CoO_x hybrid nanoparticles uniformly dispersed in mesoporous carbon. The CoN-CoO_x/C composite exhibits excellent electrocatalytic behavior for oxygen reduction reaction (ORR). The half-wave potential and durability are comparable or superior to those of Pt/C. When applying as cathode catalyst for a primary zinc-air battery, the open-circuit voltage and peak power density reach up to 1.394 V and 109.8 mW·cm⁻², respectively. A high gravimetric energy density of 950.3 Wh·kg_Zn⁻¹ is delivered at 10 mA·cm⁻² with good rate capability and stability. Density functional theory (DFT) calculation demonstrates the favorable ORR intermediate adsorbability and metallic characteristics of CoN grains with oxide hybridization to optimize the electronic structure. This work provides a facile adjustable approach for obtaining highly dispersed nanoparticles with controllable hybrid composition on a substrate, which is important for future design and optimization of high-performance electrocatalysts.