RuO₂ modification of graphene oxide-multiwalled carbon nanotubes as excellent positive electrode for vanadium redox flow battery

Vanadium redox flow batteries (VRFBs) are one of the most appealing candidates for large-scale energy storage, and hence, they have to get more developed to overwhelm commercialization obstacles such as high price of membrane and vanadium electrolyte. In this work, we have synthesized “graphene oxide (GO)-multiwalled carbon nanotubes (MWCNT)-RuO₂ ” as positive electrode material for VRFBs. The mixture of GO and MWCNT was prepared, and then, it was modified with RuO₂ nanoparticles. The FE-SEM and XRD were utilized to investigate the morphology and structure of as-prepared electrocatalyst materials. Cyclic voltammetry and electrochemical impedance spectroscopy techniques were used to look into the electrochemical performance of as-prepared electrocatalyst for vanadium IV/V redox couple reaction. GO-MWCNT-RuO₂ reduced the charge transfer resistance from 223.20 Ω (MWCNT) and 186.60 Ω (GO-MWCNT) to 94.25 Ω. The voltammograms showed that peak separation potential was decreased from 605 mV for MWCNT down to 134 mV for GO-MWCNT-RuO₂ .