ZIF-67-derived Se-doped CoSe2 grown on carbon nanofibers as oxygen electrocatalysts for rechargeable Zn–air batteries

Abstract

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 CoSe₂ embedded in carbon nanofibers (CNFs) (denoted as Se–CoSe₂/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–CoSe₂/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–CoSe₂/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.