W,O Modified-Doped Co-N-C Catalysts for Bifunctional Oxygen Electrocatalysis and Long-Cycle Zinc-Air Battery Applications

The slow kinetics of the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) significantly limit the performance and broader applications of zinc-air batteries. To address this, a series of M-N-C catalysts were synthesized using W,O-doped ZIF-67 as a precursor. By modifying the surface electronic structure through doping and improving oxygen intermediate adsorption, these catalysts demonstrated excellent bifunctional catalytic activities for OER and ORR. Among them, W,O-CoNC700 achieved the half-wave potential and overpotential of 0.81 V and 359 mV, respectively. DFT calculations revealed that doping with W atoms affected the d-band center of the Co site, thus enhancing its catalytic ability. The maximum power density of a W,O-CoNC700-based zinc-air battery reached 174.8 mW/cm², outperforming the commercial Pt/C + IrO₂ catalysts. Under constant current discharge at 5 and 10 mA/cm², the cell maintained 1100 and 450 h, respectively.