Sustainable recycling and regeneration of redox flow battery components

As the demand for large-scale sustainable energy storage grows, redox flow batteries (RFBs), particularly all-vanadium RFBs (VRFBs), have emerged as a promising solution. This review explores recycling and regeneration strategies for key VRFB components, including vanadium electrolytes, ion-exchange membranes and carbon felt electrodes, to enhance their sustainability and economic viability. Vanadium electrolytes, which account for up to 30 % of system costs, can be effectively recovered through ion-exchange and chemical reduction processes, reducing dependence on primary vanadium production. Ion-exchange membranes, primarily Nafion®, are high-cost components. While recycling methods, such as chemical dissolution and recasting show promise, challenges remain in maintaining ionic selectivity and mechanical integrity. Carbon felt electrodes, which are essential for electrochemical performance, degrade over time due to fouling and oxidation and require regeneration through thermal, chemical or physical treatments. Despite the distinct challenges of recycling each component, their effective recovery is critical for reducing operational costs, extending system lifetimes and minimizing environmental impacts. This review highlights recent technological advancements, current limitations and the broader economic and environmental benefits of sustainable recycling strategies, emphasizing their crucial role in ensuring the long-term viability of VRFBs for grid-scale energy storage.