Developing high-performance bifunctional catalysts for zinc-air batteries by utilizing Ca to modify the electronic structure of Fe

This study prepares a high-performance calcium-iron/nitrogen-doped carbon (Ca-Fe/NC) catalyst using s-block calcium and d-block iron for the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER). X-ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS) reveal a strong electronic interaction between Ca and Fe, enhancing interfacial charge transfer and catalytic activity. The catalyst demonstrates excellent performance in the ORR and OER. It shows a half-wave potential of 0.87 V and an overpotential of 320 mV at 10 mA cm^-2. A zinc-air battery assembled with Ca-Fe/NC exhibits only 1.3 % voltage decay after 150 h of operation. This research provides an effective approach for developing high-performance oxygen electrode materials through p-d orbital electron regulation.