Dimethyl Sulfoxide Treated Ti3C2TX as a Catalyst for V3+/V2+ Reaction in Vanadium Redox Flow Batteries

To enable the excellent performance of vanadium redox flow batteries (VRFBs) at high current density, dimethyl sulfoxide (DMSO) treated Ti 3 C 2 T X as an electrocatalyst for V 3+ /V 2+ reaction is proposed in this paper. Furthermore, the influence of treatment method on the property of surface terminations of Ti 3 C 2 T X and the corresponding catalytic activity toward V 3+ /V 2+ reaction is revealed. The results demonstrate that DMSO treated Ti 3 C 2 T X exhibits better catalytic activity than sodium hydroxide (NaOH) treated Ti 3 C 2 T X . The cell equipped with DMSO treated Ti 3 C 2 T X presents an energy efficiency (EE) of 81.5% and discharge capacity of 690 mAh at the current density of 150 mA·cm −2 , which is 16.2% and 30.9% higher than that with polyacrylonitrile-based graphite felt (GF). Additionally, the efficiency of the cell has no decay during 400 cycles of charge-discharge tests at 150 mA·cm −2 . The improved cell performance is attributed to abundant active sites and improved reaction kinetics toward V 3+ /V 2+ reaction due to introducing DMSO treated Ti 3 C 2 T X .