ZIF-67-derived Se-doped CoSe grown on carbon nanofibers as oxygen electrocatalysts for rechargeable Zn-air batteries

Exploring bifunctional electrocatalysts for oxygen evolution reaction (OER) and oxygen reduction reaction (ORR), which combine the features of effective electrocatalytic activity, high electrical conductivity, and superior stability, remains a significant challenge for rechargeable Zn-air batteries (ZABs). Herein, we report a material, selenium (Se)-doped CoSe 2 embedded in carbon nanofibers (CNFs) (denoted as Se-CoSe 2 /CNFs), which was synthesized as a bifunctional electrocatalyst for ZABs via electrospinning combined with in situ growth of Zeolitic Imidazolate Framework-67 strategy, followed by carbonization and a facile selenization process. The as-synthesized Se-CoSe 2 /CNF electrode exhibits satisfactory electrochemical performance in an alkaline environment with a low overpotential of 325 mV at 10 mA cm −2 toward OER and a half-wave potential of 0.80 V for ORR. Remarkably, the Se-CoSe 2 /CNF catalyst-based ZAB shows a peak power density of 149.4 mW cm −2 and the voltage window barely changes after 180 h of cycling at 5 mA cm −2 , which proves its great potential application for advanced bifunctional electrocatalysis in ZABs. Se-doping can reduce the charge transfer resistance and enhance the OER kinetics. CNFs significantly improved the electrical conductivity of the materials. The ZIF-67-derived carbon skeleton provides an electron transport channel.