Co 3 O 4 nanofibers compounded with Pt/C as efficient bifunctional electrocatalysts for rechargeable Zn-air battery

Exploring efficient bifunctional electrocatalysts is critical for metal-air battery commercialization. Co 3 O 4 produced by electrospinning was combined with Pt/C via ultrasonic vibration in this study. As a bifunctional oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) electrocatalyst, Co 3 O 4 @Pt/C nanofibers were employed. The Co 3 O 4 @Pt/C nanofibers with a mass ratio of 1:1 (CP11) show excellent OER activity. It outperforms commercial Pt/C and Co 3 O 4 electrocatalysts with a low overpotential (442 mV) and Tafel slope (71.36 mV dec − 1 ) at 10 mA cm − 2 . With a half-wave potential of 0.74 V and diffusion limiting current density of 4.3 mA cm − 2 , CP11 provides exceptional catalytic activity for ORR. The expanded surface area of Co 3 O 4 nanofibers and the unique interaction between the Pt/C and metal oxides may be responsible for the high bifunctional catalytic activity of Co 3 O 4 @Pt/C nanofibers. More importantly, the zinc-air battery based on CP11 has a 0.64 V charging-discharging voltage gap and long-term stability. The improved OER/ORR bifunctional performance of Co 3 O 4 @Pt/C demonstrates the feasibility of using it in high-power energy storage and conversion devices.