Improvement of Titanium Dioxide Addition on Carbon Black Composite for Negative Electrode in Vanadium Redox Flow Battery

This study investigates the effects of adding titanium dioxide (TiO 2 ) particles to the negative electrode of a vanadium redox flow battery (VRFB) on the battery's performance. Results show that TiO 2 addition changes the wettability and electrical resistance of the electrode surface. The water contact angle on the electrode surface decreases with increased weight percentage of TiO 2 particles in the electrode. The electrochemical performance of these electrodes with different loading amounts is studied by cyclic voltammetry and single-cell charge–discharge measurements. Adding an adequate amount of TiO 2 particles to the carbon electrode promotes the electrode specific capacitance and charge–discharge efficiency of a single cell. An electrode with 20 wt% TiO 2 loading at a scan rate of 0.04 V s −1 shows a high specific capacitance ( C s,t ) of 156.2 F g −1 , which is 59.1% higher than that of pure carbon electrode (98.2 F g −1 ). Similarly, the energy storage efficiency ( η E = 72.5%) of a single TiO 2 /C cell with 20 wt% modified carbon felt is 30.4% higher than that of a cell with raw carbon felt ( η E = 55.6%). Thus, the TiO 2 /C electrode increases the cell energy storage efficiency. These results demonstrate the potential application of TiO 2 /C electrode in VRFBs.