Experimental study on CNT nanofluids for vanadium redox flow battery

A Vanadium redox flow battery (VRFB) single-cell system using a nanofluid was experimentally investigated to increase the energy capacity. The nanofluids used in this study were prepared and dispersed through a simple method of adding a multi-wall carbon nanotube (MWCNT) to an electrolyte solution, which consisted of a 1.6 M VO2 an electrolyte and a 4 M H2SO4 electrolyte. The weight ratios of these solution components were 0.05, 0.1, and 0.2 wt%, respectively. XRD and Raman spectroscopy were used for the structural and quantitative analysis of the MWCNT. For the electrochemical analysis of the nanofluids, 20 charge/discharge cycles were carried out and compared with the general electrolyte for determining the energy capacity. The energy capacity and average voltage results were on the order of 0.1 wt% > general electrolyte > 0.05 wt% > 0.2 wt%. The energy capacity of a 0.1 wt% nanofluid was 0.2 Ah/L higher than a pristine electrolyte. © 2017 The Korean Society of Mechanical Engineers.