Bimetallic–organic framework-derived Co–ZnO grown on carbon nanofibers as a bifunctional electrocatalyst for rechargeable Zn–air batteries

Abstract

For rechargeable Zn–air batteries (ZABs), developing bifunctional electrocatalysts for the oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) with cost-effectiveness, excellent performance, and high stability is of critical importance. Co–ZnO grown on carbon nanofibers (named Co–Zn/CNFs-2) has been synthesised as a highly active bifunctional electrocatalyst for ZABs by electrospinning combined with in situ growth of a bimetallic organic framework and subsequent carbonization. The as-prepared Co–Zn/CNFs-2 catalyst exhibited remarkable bifunctional catalytic activity (288 mV at 10 mA cm⁻² for the OER and a half-wave potential of 0.816 V for the ORR in an alkaline electrolyte). In addition, a ZAB employing Co–Zn/CNFs-2 as the air cathode delivered a considerable power density of 318.22 mW cm⁻² and a specific capacity of 840.88 mA h g⁻¹ (10 mA cm⁻²). Moreover, the cycling stability test showed almost no change in the voltage window after 1000 h of cycling at 5 mA cm⁻², indicating its considerable potential for application in advanced bifunctional electrocatalysis of ZABs.