Decoration of Vanadium Pentoxide on Conductive Carbon Nanotube Framework As Electroactive Materials for Aqueous Supercapacitors

Supercapacitors (SCs) have been regarded as energy-storage devices that performance between conventional capacitors and batteries. They commonly have higher energy densities, deliver higher power densities, long cycling life and faster charge/discharge rates than conventional batteries. The charge storage mechanisms of SCs are generally divided into the following two types. The one is electric double-layer capacitors (EDLCs) which originates from the charge accumulation process at the electrode/electrolyte interface, and the other type is pseudocapacitors in which the charge storage mechanisms occurs through the faradic redox reactions. Among the transition-metal oxides, vanadium pentoxide (V 2 O 5 ) has layered structure, the satisfactory charge storage capacity, a modest electronic conductivity, unique advantages of high energy density and wide potential window arising from its various vanadium oxidation states. In this work, we successfully decorated V 2 O 5 thin layer on the surface of conductive carbon nanotubes (CNTs), designated as CNT@V 2 O 5 , by using pulsed-mode electrodeposition. It was found that the as-deposited V 2 O 5 thin film is with nano-crystalline nature and the surface of the CNTs is evenly deposited with it. The as-deposited CNT@V 2 O 5 electrode can reveal an enhanced discharge capacitance of 198 F/g at current density of 1 A/g in 2 M NaNO 3 aqueous electrolyte.