Synthesis and Characterization of Mn3O4 Doped Modified Electrodes for Vanadium Redox Flow Batteries

In the present study, Mn 3O4 doped electrodes were synthesized to improve the cathode V (IV)/V (V) redox reaction of all vanadium flow batteries. Cathode electrocatalysts were produced with a two-step hydrothermal method. The crystal structure of the Mn3O4 doped composites and electrodes were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM) was used for morphological examination of the samples. Surface modification of the electrodes was confirmed by thermo gravimetric analysis (TGA) and functional groups on the electrode surface were determined by X-ray Photoelectron Spectroscopy (XPS). Electrochemical measurements of the electrodes were conducted with cyclic voltammetry (CV) technique. Mn3O4 directly loaded onto graphite felt and carbon paper and Mn3O4/Vulcan XC-72 nanocomposite increased the electrochemical catalytic activity of cathode V (IV) / V (V) redox reaction. Peak currents of Mn3O4/Vulcan XC-72 doped graphite felt and SGL 10AA electrodes are measured as 42.30 and 7.9 mA, respectively. Despite the low electrical conductivity of Mn3O4 , the composites formed with Vulcan XC-72 improved vanadium flow battery cathode performance.