Core-shell hollow dodecahedron derived Co nanoparticle/Cu single-atom for efficient oxygen reduction/oxygen evolution and flexible zinc-air batteries

Efficient and low-cost electrocatalysts for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are crucial for the development of zinc-air batteries (ZABs). In this study, we designed a Core-shell hollow zeolitic imidazolate framework (ZIF) material Cu-ZIF-67/ZIF-8 with Cu-doped ZIF-67 (Cu-ZIF-67) core and a ZIF-8 shell. The hollow structure (ZIF-67/ZIF-8-h) was constructed via solvent-assisted phase transformation. The hollow structure, characterized by hierarchical porosity, not only facilitated mass transfer but also served as a prerequisite for Cu SAC formation, leading to coexisting of Cu single atoms (Cu SAC) and Co nanoparticles (Co NPs) after pyrolysis. Cu SAC modulated the d-band center of Co NPs, optimizing the adsorption of oxygen-containing intermediates. In alkaline media, Cu-Co/CN-h exhibited excellent bifunctional catalytic activity, with an ORR half-wave potential of 0.93 V and an OER overpotential of 338 mV at 10 mA cm −2 . When used as the cathode in a flexible ZABs, Cu-Co/CN-h demonstrated a high peak power density of 108 mW cm −2 and outstanding durability over 60 h. This work innovatively provides a strategy for break traditional scaling relationships with hierarchal porosity and synergistic Cu-Co sites.