A Nano-Carbon Scaffold (NCS) Electrode for the Vanadium Redox Flow Battery

Abstract

In this study a template nano-carbon scaffold (NCS) electrode material is evaluated for use in the vanadium redox flow battery (VRB). Scanning electron microscopy (SEM) was used to characterize the morphology of the electrode materials. This material has an organized nanoporous structure and the pore size can be as small as 18nm. The electrochemical properties of the NCS materials were explored using cyclic voltammetry (CV). To investigate the performance of NCS as an electrode material, the NCS was attached to the surface of conventional carbon paper electrodes. The charge discharge performance of the VRB was determined using a flow through mode of operation. The performance of nano carbon scaffold (NCS) with different pore size and thickness was compared with a conventional heat-treated carbon paper. The results show that by using nano carbon scaffold (NCS-85-HT), the voltage efficiency increased from 77% to 94% at 10 mAcm-2. The energy efficiency also increased from 56% to 69% at 10 mAcm-2due to the increased voltage efficiency. The results indicate that the large surface area of the NCS, associated with its nano structure, lead to a reduction in overpotential of around 75%, and thus higher battery efficiencies. Cell performance under different current density was also explored and the improved efficiencies for NCS were maintained at all the current densities studied.