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·kgZn^(−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.