Resolving charge-transfer and mass-transfer processes of VO2+/VO2+redox species across the electrode/electrolyte interface using electrochemical impedance spectroscopy for vanadium redox flow battery

• DOI: 10.1039/d0ra05224h
• Publication Date: 2020-08-20T12:59:11Z
• Authors: Pradipkumar Leuaa; Divya Priyadarshani; Debittree Choudhury; Rajan Maurya; Manoj Neergat
• Keywords: Charge transfer coefficient

Electrochemical impedance spectroscopy is used to investigate the charge-transfer and mass-transfer processes of VO2+/VO2 + (V4+/V5+) redox species across carbon-modified glassy carbon disk electrode/electrolyte interface. The features EIS patterns depend on potential, concentrations mass-transport conditions at With starting electrolyte containing either only V4+ or V5+ species, shows a straight line capacitor feature, as no oxidation reduction reaction take place measured open circuit potential (OCP). equimolar concentration V5+, pattern has both equilibrium potential. process are observed be influenced by process. Optimum V4+/V5+ supporting H2SO4 required resolve corresponding underlying physical processes. semi-infinite linear diffusion characteristics with static condition electrode converges that finite under hydrodynamic condition.