Bifunctional oxygen evolution reaction and oxygen reduction reaction catalysts prepared by high gravity-hydrothermal method for rechargeable zinc air batteries

Oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) are cathodic reactions of rechargeable zinc air batteries (ZABs), and their slow kinetics and multiple complex processes directly determine the overall energy efficiency and cycle life of ZABs. Exploring high activity, high stability and low cost non precious metal electrocatalysts for ZABs and their preparation method is of great significance. In this paper, a composite catalyst named Co/CoO@PNC has been prepared by scalable high gravity-hydrothermal method with a distinctive core shell structure of Co/CoO active particles uniformly loaded on polyaniline-derived one-dimensional nitrogen doped carbon material. The synergistic effect between each component enables Co/CoO@PNC to exhibit excellent bifunctional OER/ORR catalytic activity, which has a lower value of Delta E of 0.703 V. When Co/ CoO@PNC is used as the catalyst of rechargeable ZABs, the power density is 156.5 mW/cm2, with a specific capacity of 821 mAh/g and strong charging and discharging ability, better than Pt/C + RuO2. After more than 250 h of charge and discharge cycles, there is no significant decrease in performance. This article provides a high performance bifunctional OER/ORR catalyst without precious metals and its low-cost, simple and scalable preparation method.