Lignin as redox-targeted catalyst for the positive vanadium electrolyte

Vanadium Redox Flow Batteries (VRFBs) are promising candidates for large- scale energy storage applications however, there still some obstacles that need to be overcome such as their low density (25–30 Wh L−1 a 1.8 M electrolyte), high cost and large environmental impact due corrosiveness the unsustainability of vanadium. To address these challenges, we introduce lignin low-cost electrocatalyst capacity booster positive electrolyte. Coated on glassy carbon electrode, showed electrocatalytic abilities improved electrochemical reversibility VO2+/VO2+ redox couple significantly. In charge discharge cycles volumetric capacities 28 Ah (charge) 23.5 (discharge) were achieved with 0.9 concentrated vanadium electrolyte which surpassed maximum theoretical 24.1 in charge. This demonstrates an increase 7.5 9 cycles, respectively, compared pristine felt electrode. work showcases noteworthy influence opens new possibilities VRFB chemistry.