3d orbital electron engineering in oxygen electrocatalyst for zinc-air batteries

The optimization of 3d electron configurations is considered a feasible approach to improve the catalytic activity of transition metal nitrogen carbon (TM-N-C) electrocatalysts. Herein, by stacking Fe-Ni dual-metal on carbon substrate to obtain (Fe, Ni)@N-MWCNTs as model objects, we reveal that Fe3+ with high spin in Fe-Ni sites which possesses 3d electron configurations suitable for both OER and ORR. Specifically, the metal sites can be effec-tively activated by both 3d electron configurations optimization and the charges donated from the carbon substrate, which can balance the competition between OER and ORR process, rendering the excellent bifunc-tional performances with a small potential difference (Delta E = 0.828 V). In addition, it further provides an excellent performance and cycling stability in aqueous zinc-air batteries. The assembled wearable flexible zinc-air batteries also provide stable cycling performance and can be worn as a wristband to light up LED lights.