Tuning active sites for highly efficient bifunctional oxygen electrocatalysts of rechargeable zinc-air battery

High activity, excellent durability, and low-cost oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) bifunctional catalysts are highly required for rechargeable zinc (Zn)-air batteries. Herein, we designed an electrocatalyst by integrating the ORR active species of ferroferric oxide (Fe3O4) and the OER active species of cobaltous oxide (CoO) into the carbon nanoflower. By well regulat-ing and controlling the synthesis parameters, Fe3O4 and CoO nanoparticles were uniformly inserted into the porous carbon nanoflower. This electrocatalyst can reduce the potential gap between the ORR and OER to 0.79 V. The Zn-air battery assembled with it exhibited an open-circuit voltage of 1.457 V, a stable discharge of 98 h, a high specific capacity of 740 mA h g-1, a large power density of 137 mW cm -2, as well as good charge/discharge cycling performance, exceeding the performance of platinum/carbon (Pt/C). This work provides references for exploring highly efficient non-noble metal oxygen electrocatalysts by tuning ORR/OER active sites.(c) 2023 Elsevier Inc. All rights reserved.

Automated summary

Highly efficient bifunctional catalysts for ORR and OER are essential for rechargeable Zn-air batteries. In this study, Fe3O4 and CoO nanoparticles were integrated into carbon nanoflowers to create an electrocatalyst that reduced the potential gap between ORR and OER to 0.79 V. The Zn-air battery assembled with this catalyst exhibited superior performance compared to Pt/C, including a higher open-circuit voltage, longer discharge time, higher specific capacity, and larger power density.