Utilization of recovered vanadium pentoxide solution from a spent vanadium catalyst as an efficient electrolyte in an...

ObjectiveThe present investigation aims to utilize the extract of vanadium pentoxide from spent vanadium catalyst in a tabletop vanadium redox flow battery (VRFB) and a home-designed cell stack. The most commonly used redox couples in VRFB systems are V²⁺/V³⁺ and V⁴⁺/V⁵⁺ which typically require the use of costly VOSO₄ standard solution. In this study we propose an alternatve approch by substituting these expensive solutions with more affordable and environmentally friendly option: a V₂O₅ solution derived from spent catalyst.MethodCharacterization of the recovered vanadium solutions, incorporation of these solutions were performed in a three electrode cell and in a real bench-top vanadium storage battery model, and the performance of the constructed battery was tested using different electrochemical techniques such as cyclic voltammetry.ResultThe increasing current and potential observed were proportional to the concentration of the recovered solution. Furthermore, an in-house tabletop VRFB utilizing the recovered electrolyte exhibited promising electrochemical properties, achieving a maximum discharge potential of 2.0 V after 180 minutes of electrical charging and a maximum current of 83.5 mA. These results are encouraging for the utilization of recovered vanadium solutions in VRFBs.ConclusionThis study results are encouraging for the utilization of recovered vanadium solutions in VRFBs. This work suggests a novel technique that utilizes waste vanadium solutions from the sulfuric acid industry for sustainable VRFB applications.