Facile Composition of CoNi and Graphene as a Free-Standing Cathode for a High-Performance Solid-State Zinc-Air Battery

The development of solid-state zinc-air batteries (SZABs) has stimulated significant interest. However, the practical use of SZABs still encounters difficulties due to the complicated preparation process and low-performance air cathode. In this study, we developed a free-standing CoNi/graphene composite cathode without current collectors and binders. The simplified cathode structure decreased the preparation process, and the self-assembled conductive matrix increased charge transfer, which holds promise for facile preparation and high-performance SZABs. Specifically, a free-standing CoNi/graphene film was fabricated by a simple composition method. The CoNi/graphene electrocatalyst exhibited comparable oxygen reduction reaction (ORR) catalytic activity to that of Pt/C. Furthermore, the CoNi/graphene film could be directly used as a cathode, which showed an open-circuit voltage of 1.41 V and a power density of 210 mW cm-2 in alkaline liquid ZABs, as well as an open-circuit voltage of 1.43 V and a power density of 40 mW cm-2 in alkaline SZABs. This facile preparation and excellent performance offer substantial potential for practical SZAB applications.