Synergistic Co/Cu heterophase nanoparticles embedded in microporous and mesoporous carbon with hydrophobicity for high-power density zinc-air battery

The slow dynamics on the air cathode side of zinc-air batteries and the high overpotential severely hinder their commercial development. This urgently requires a significant improvement in the kinetics of the cathodic oxygen reduction reaction (ORR) and enhancement of the catalyst's ORR/OER catalytic performance. Here, a novel ORR/OER bifunctional catalyst, CoCu-NC with excellent hydrophobicity, is reported to address these issues. Cu-modified Co nanoparticles (Co/Cu) are encapsulated in a leaf-like porous nitrogen-doped carbon material. The Co/Cu heterophase modulates the electronic states of the CoCu-NC catalyst, thus optimising its ORR/OER performance. On the other hand, the CoCu-NC catalyst with abundant voids and hydrophobic microstructures on lotus leaf-like surfaces enhances the kinetic process of the electrocatalytic reaction. Therefore, the CoCu-NC catalyst exhibits excellent electrocatalytic activity with an ORR half-wave potential of 0.89 V, an oxygen evolution overpotential of 180 mV, and a potential gap ΔE of 0.52 V. The corresponding liquid ZAB achieves a high peak power density of 198 mW cm^-2, while the quasi-solid ZAB also demonstrates a peak power density of up to 513 mW cm^-2. The CoCu-NC catalyst shows great potential in the ZAB field, providing new material design concepts for the development of high-power density zinc-air batteries.