Towards Bio-derived Electrolytes for Sustainable Redox Flow Batteries

The transition to renewable energy systems has intensified the need for sustainable, large-scale energy storage solutions, and redox flow batteries (RFBs) have emerged as a promising technology due to their scalability, safety, and long cycle life. However, conventional RFBs that rely on metal-based electrolytes face significant challenges, including high cost, resource scarcity, and environmental toxicity. Bio-derived electrolytes offer a sustainable alternative that combines renewable sources with tunable electrochemical properties. This review comprehensively summarizes the latest progress of RFB bio-derived electrolytes and discusses the electrochemical performances of plant-derived quinones, lignin derivatives, and fungal metabolites. The limitations in the systems, such as lower solubility limits, crossover issues, and long-term stability are evaluated, with suggested future research directions. The work provides valuable insights for the development of next-generation green RFB systems, which align with global sustainability goals.