Vanadium oxide nanowire-carbon nanotube binder-free flexible electrodes for supercapacitors

Abstract

Vanadium pentoxide (V 2O 5) layered nanostructures are known to have very stable crystal structures and high faradaic activity. The low electronic conductivity of V 2O 5 greatly limits the application of vanadium oxide as electrode materials and requires combining with conducting materials using binders. It is well known that the organic binders can degrade the overall performance of electrode materials and need carefully controlled compositions. In this study, we develop a simple method for preparing freestanding carbon nanotube (CNT)-V 2O 5 nanowire (VNW) composite paper electrodes without using binders. Coin cell type (CR2032) supercapacitors are assembled using the nanocomposite paper electrode as the anode and high surface area carbon fi ber electrode (Spectracarb 2225) as the cathode. The supercapacitor with CNT-VNW composite paper electrode exhibits a power density of 5.26 kW Kg -1 and an energy density of 46.3 Wh Kg -1. (Li)VNWs and CNT composite paper electrodes can be fabricated in similar manner and show improved overall performance with a power density of 8.32 kW Kg -1 and an energy density of 65.9 Wh Kg -1. The power and energy density values suggest that such fl exible hybrid nanocomposite paper electrodes may be useful for high performance electrochemical supercapacitors. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.