Co3O4/Mn3O4 hybrid catalysts with heterointerfaces as bifunctional catalysts for Zn-air batteries

Zinc-air batteries (ZABs) with high energy density and safety are promising as next-generation energy storage systems, while their applications are severely hindered by the sluggish reaction kinetic of air cathodes. Developing a bifunctional catalyst with high activity and durability is an effective strategy to address the above challenges. Herein, a Co3O4/Mn3O4 nanohybrid with heterointerfaces is designed as advanced cathode catalyst for ZABs. Density functional theory calculations show the heterogeneous interface between Co3O4/Mn3O4 can improve the dynamics of carrier transport and thus enhancing the catalytic activity and durability. The Co3O4/Mn3O4 catalyst anchored on reduced graphene oxide (rGO) exhibits high oxygen reduction reaction (ORR) activity with a half-wave potential of 0.86 V, and excellent oxygen evolution reaction (OER) activity with the potential of 1.59 V at 10 mA cm(-2), which are comparable to the commercial noble metal catalysts. The improved ORR/OER catalytic activity is ascribed to the synergistic effect of heterointerfaces between Co3O4 and Mn3O4 as well as the improved conductivity and contact area of oxygen/catalysts/electrolytes three-phase interface by rGO. Furthermore, a home-made ZAB based on Co3O4/Mn3O4/rGO shows a high open circuit voltage of 1.54 V, a large power density of 194.6 mW cm(-2) and good long-term cycling stability of nearly 400 h at 5 mA cm(-2), which affords a promising bifunctional oxygen catalyst for rechargeable ZABs. (C)& nbsp;2021 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences Published by Elsevier B.V. All rights reserved.

Automated summary

A Co3O4/Mn3O4 nanohybrid with heterointerfaces is designed as an advanced cathode catalyst for Zinc-air batteries (ZABs), which shows high activity and durability in oxygen reduction reaction and oxygen evolution reaction. The improved catalytic activity is attributed to the heterointerfaces between Co3O4 and Mn3O4 as well as the improved conductivity and contact area of the three-phase interface. The home-made ZAB based on Co3O4/Mn3O4/rGO exhibits high open circuit voltage, large power density, and good long-term cycling stability, making it a promising bifunctional oxygen catalyst for rechargeable ZABs.