Performance improvement of non-aqueous iron-vanadium flow battery using chromium oxide–modified graphite felt electrode

The non-aqueous redox flow battery (NARFB) has received extensive attention in large-scale energy storage systems, but its electrochemical performance needs to be improved. In this study, electrode modification was performed by depositing non-noble metal chromium oxide on the surface of graphite felt by impregnation combined with high-temperature calcination. The results show that the graphite felt electrode decorated with Cr2O3 has a good electrocatalytic effect on the redox reaction of Fe(II)/Fe(III). In addition, the polarization curve test shows that the power density of the modified electrode reaches 11.22 mW·cm−2 (15% increment). In the charge–discharge cycle test, the NARFB assembled with the chromium oxide–modified electrode has an energy efficiency of 87.2%. This work provides a potential way to improve the performance of NARFB with deep eutectic solvent (DES) electrolytes.