Fabrication of cobalt oxide/carbon core-branch nanowire arrays as cathode materials for supercapacitor application

Abstract

Porous core-branch nanowire arrays are critical for developing advanced electrochemical devices. In this work, Co3O4/C core-branch nanowire arrays are successfully fabricated by combining hydrothermal synthesis and atomic layer deposition (ALD) methods. Interconnected amorphous carbon nanoflakes are homogeneously coated on the Co3O4 nanowire core forming Co3O4/C core-branch nanowires with diameters of ~280nm. Supercapacitor electrodes based on the Co3O4/C core-branch nanowire arrays are tested. The Co3O4/C core-branch nanowire arrays exhibit excellent electrochemical performances with a high capacitance of 700Fg−1 at 2Ag−1 as well as good cycling stability due to the attractive characteristics such as good conductivity, porous structure and direct growth on the conductive substrates. Our synthetic approach may pave the way for fabrication of other metal oxides/carbon arrays for applications in electrochemical energy storage.