Nano TiC electrocatalysts embedded graphite felt for high rate and stable vanadium redox flow batteries

Abstract

Developing electrodes with high stability and activity is critical to promoting the application of redox flow batteries. In this work, a multiscale-pore-network structured graphite felt embedded nano-sized TiC electrocatalysts is fabricated by fully utilizing the Ti and O atoms of TiO2 nano seeds. For the present electrode, the micro pores shaped by the crossed carbon fibers serve as pathways for electrolyte convection. At the same time, the simultaneous formation of TiC during nanopore fabrication can catalyze the V3+/V2+ redox reaction. The electrode leads to the battery performance with an energy efficiency of 85.2% and an electrolyte utilization of 82.7% at a current density of 200 mA cm−2, respectively 23.3% and 48.6% higher than the battery with pristine electrodes. Also, even at 300 mA cm−2, the battery's energy efficiency and electrolyte utilization with this electrode can still be maintained at 80.8% and 72.6%, respectively 14.0% and 29.6% higher than the thermally treated electrode. Moreover, the present battery demonstrates a stable energy efficiency above 80% during cycle tests. The results indicate that engineering structures of electrocatalysts in nanopores may open new avenues for advancing flow battery electrode technology.