Improved Performance of Ti/Mn Redox Flow Battery by Thermally Treated Carbon Paper Electrodes

In this paper we investigate the effect of heat treatment of carbon papers on Ti-Mn redox system. The heat treatment improves the redox reaction kinetics of carbon paper electrode for both positive and negative half-cell. It is considered that the enhanced kinetic performance is attributed to the increased wettability of carbon surface, because a significant increase in the surface area was not observed. In the full-cell evaluation, mass transport loss increased significantly with increasing the state of charge. It is considered that the precipitation of MnO2 caused decrease of reactants and prevented reactants diffusion. The low kinetics of negative half-cell limited the cell performance. The cell performance has been greatly improved by using a high capacitance carbon felt as negative electrode. A high energy efficiency of 83.2% at current density of 100 mA cm-2 was obtained in a single cell test.