Synthesis of chemical vapor deposition graphene on tantalum wire for supercapacitor applications

•The capacitance of graphene/tantalum (Ta) wire electrodes is firstly reported.•Graphene was grown on the Ta surface by hot-filament chemical vapor deposition.•Graphene/Ta wire structure is favorable for fast ion and electron transfer.•The graphene/Ta wire electrode shows high capacitive properties. This paper studies the synthesis and electrochemical characterization of graphene/tantalum (Ta) wires as high-performance electrode material for supercapacitors. Graphene on Ta wires is prepared by the thermal decomposition of methane under various conditions. The graphene nanosheets on the Ta wire surface have an average thickness of 1.3–3.4nm and consist typically of a few graphene monolayers, and TaC buffer layers form between the graphene and Ta wire. A capacitor structure is fabricated using graphene/Ta wire with a length of 10mm and a diameter of 0.6mm as the anode and Pt wire of the same size as the cathode. The electrochemical behavior of the graphene/Ta wires as supercapacitor electrodes is characterized by cyclic voltammetry, galvanostatic charge/discharge, and electrochemical impedance spectroscopy in 1M Na2SO4 aqueous electrolyte. The as-prepared graphene/Ta electrode has highest capacitance of 345.5Fg−1 at current density of 0.5Ag−1. The capacitance remains at about 84% after 1000 cycles at 10Ag−1. The good electrochemical performance of the graphene/Ta wire electrode is attributed to the unique nanostructural configuration, high electrical conductivity, and large specific surface area of the graphene layer. This suggests that graphene/Ta wire electrode materials have potential applications in high-performance energy storage devices.