The recent advances of graphene/Co3O4 composites for rechargeable zinc–air batteries

Rechargeable Zn-Air batteries (ZABs) are becoming the most popular option for energy storage devices for electronic devices and electric vehicles because of its high theoretical specific energy density, abundance, affordability, and environmental friendliness. Nevertheless, ZABs need inexpensive, ecologically safe, and highly effective oxygen catalysts. Because of their good electrochemical activity, high theoretical specific capacitance, non-toxicity, and relatively inexpensive cost, cobalt-based materials particularly Co 3 O 4 and its composites have gained popularity as ZAB electrode materials over the past ten years. Furthermore, the development of energy devices investigates the special structure and characteristics of two-dimensional graphene-based materials. The applications of graphene, a two-dimensional monolayer planar sheet of sp 2 -bonded carbon atoms, have undergone a revolution in recent years due to its exceptional unique properties, which include a large specific surface area, remarkable thermal and electronic conductivity, mechanical strength and physicochemical properties. Henc, this review focuses the recent developments on designing of graphene/Co 3 O 4 composites and their application for ZABs. A summary of Co 3 O 4 's electrochemical benefits as a electrode material is provided, along with numerous examples. Future research directions are suggested, along with a discussion of the ongoing difficulties in investigating graphene/Co 3 O 4 composite materials as effective ZAB electrodes.