Affiliation:
1. State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology No. 122 Luoshi Road Wuhan 430070 China
2. R&D Center of Materials and Stack Technology for Fuel Cell Foshan Xianhu Laboratory of the Advanced Energy Science and Technology Guangdong Laboratory Foshan 528200 China
3. Hubei Key Laboratory of Fuel Cell Wuhan University of Technology No. 122 Luoshi Road Wuhan 430070 China
Abstract
AbstractStable, efficient, and economical bifunctional electrocatalysts for oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) are needed for rechargeable Zn–air batteries. In this study, a directional electron transfer pathway is exploited in a spatial heterojunction of CoyNix@Fe─N─C heterogeneous catalyst for effective bifunctional electrolysis (OER/ORR). Thereinto, the Co/Ni alloy is strongly coupled to the Fe─N─C support through Co/Ni─N bonds. DFT calculations and experimental findings confirm that Co/Ni─N bonds play a bridging role in the directional electron transfer from Co/Ni alloy to the Fe─N─C support, increasing the content of pyridinic nitrogen in the ORR‐active support. In addition, the discovered directional electron transfer mechanism enhances both the ORR/OER activity and the durability of the catalyst. The Co0.66Ni0.34@Fe─N─C with the optimal Ni/Co ratio exhibits satisfying bifunctional electrocatalytic performance, requiring an ORR half‐wave potential of 0.90 V and an OER overpotential of 317 mV at 10 mA cm−2 in alkaline electrolytes. The assembled rechargeable zinc–air batteries (ZABs) incorporating Co0.66Ni0.34@Fe─N─C cathode exhibits a charge–discharge voltage gap comparable to the Pt/C||IrO2 assembly and high robustness for over 60 h at 20 mA cm−2.
Funder
National Natural Science Foundation of China