Synergistic interaction between embedded Co3O4 nanowires and graphene papers for high performance capacitor electrodes

Abstract

Graphene/Co₃O₄ nanowire composite films were successfully synthesized using a simple, three-step treatment, and the effect of the Co₃O₄ nanowire content on the electrochemical properties of the composite films was studied. The one-dimensional Co₃O₄ nanowires were homogeneously embedded and dispersed between prepared graphene papers, forming a layered graphene/Co₃O₄ nanowire hybrid structure. These composite films exhibited better electrochemical properties than previously reported ones, such as graphene/CNT, where carbon spheres existed in the graphene composites, which were fabricated using the same method but without the Co₃O₄ nanowires. The addition of a small amount of Co₃O₄—typically 8 : 1 by weight (reduced graphene oxide (RGO) : Co₃O₄)—to form thick RGO/Co₃O₄ sandwiches in the form of papers resulted in an excellent specific charge capacity of 278.936 C g⁻¹ at a scan rate of 5 mV s⁻¹. These results indicate the potential of the composite for the development of highly capacitive energy storage devices for practical applications.