The characteristics and electrochemical performance of graphite felts with thermal and fenton's reagent treatment for vanadium redox flow battery

Abstract

In this study, we modified the surface morphology and functional group of graphite felts (GFs) through thermal and Fenton’s reagent treatment. The modified GFs were used as electrodes for vanadium redox flow batteries (VRFBs). Surface morphology, wettability, chemical composition and electrochemical performance of GFs were characterized through contact angle measurement, X-ray photoelectron spectroscopy, cyclic voltammetry, electrochemical impendence spectroscopy, and charge discharge testing. The charge transfer resistance of the GFs after thermal and Fenton’s reagent treatment was lower than that of unmodified GF because of the high specific surface areas and hydroxyl group formation on the surface of the modified GFs. The VRFBs based on GFs modified through thermal and Fenton’s reagent treatment exhibited superior electrochemical performance when comparing with the unmodified GF electrode. The GF with heat treatment at 500 °C for 3 h and Fenton’s reagent treatment had high Coulombic efficiency, voltage efficiency and energy efficiency of 94.84%, 81.77% and 77.55% at 60 mA/cm2, respectively.