Improved performance of iron-based redox flow batteries using WO3 nanoparticles decorated graphite felt electrode

Abstract

Iron flow batteries are having tremendous attraction because of their economic feasibility and environmentally favorable electrolytes. Electrode and electrolyte used in iron-based redox flow batteries (IRFBs) have a vital role in the performances of electrochemical energy storage devices. Therefore designing a suitable electrode and optimization of electrolyte composition is highly needed. Graphite is one of the appropriate electrodes used in flow batteries but they have to be modified to improve the electrical performance. Here, for the first time, WO3 nanoparticles (WONs) were used to modify graphite felt electrode for IRFBs applications. The effect of loading mass per unit cm2 of electrochemically active material has been investigated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization (Tafel) studies. The ligand based iron-electrolyte along with anion exchange membrane has been selected for the studies. The performance of the modified graphite felt electrode (3 mg/cm2) assembled in 132 cm2 cell results in a peak power density of 53 mW/cm2 at 40 mA/cm2. This study provides information about the improvement in the electrochemical performance of IRFBs.