Study for the Influence of Thermal and Acid Treatment on the Graphite Felt as an Electrode for Vanadium Redox Flow Battery

초록

Redox flow battery (RFB) is a type of reversible energy storage system (ESS) which converts the chemical energy to electrical energy through the electrochemical cell. Among them, vanadium redox flow battery (VRFB) is most commonly studied owing to its high energy efficiency, long cycle life and low maintenance cost.1 In this work, the graphite felt was modified by thermal and acid treatment. Graphite felt were treated thermally in air condition at various temperatures from 300℃ to 600℃ for 5h. And samples were treated with sulfuric acid of various concentrations from 3M to 5M for 5h.2-3 The physicochemical properties of treated graphite felt are investigated by X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). And electrochemical properties are investigated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) in a standard three electrode system at a scan rate 10 mV/s using a potentiostat. As a result, the modified graphite felt electrodes showed best electrochemical performance compared with the raw electrode owing to the functional groups on the surface of electrodes.