A comprehensive review of metal-based redox flow batteries: progress and perspectives Redox flow batteries (RFBs) are considered a leading technology for large-scale energy storage, integrating with intermittent renewable energy sources like wind and solar to overcome the limitations of conventional storage systems. Recent advancements have focused on improving energy efficiency, longevity, and cost-effectiveness of RFBs. The review highlights key developments, current trends, and research gaps in metal-based RFBs, including their components, performance, and challenges. It provides a detailed analysis of the cost, associated challenges, and mitigation strategies of RFBs, along with a table comparing electrode/electrolyte materials for quick reference. RFBs are electrochemical cells that convert chemical energy into electrical energy through redox reactions in the electrolyte. They offer advantages over conventional batteries, such as separable components, higher energy storage capacity, and design flexibility. Vanadium redox flow batteries (VRFBs) are widely used due to their high energy density and long-term performance. However, organic redox flow batteries (ORFBs) are also gaining attention for their potential in sustainable and cost-effective energy storage. The review discusses the main components of RFBs, including membranes, bipolar plates, electrodes, and electrolytes. Membranes play a critical role in separating electrolytes and controlling ion exchange. Different types of membranes, such as ionic exchange membranes, porous separators, and composite membranes, are analyzed for their performance in RFBs. The review highlights the importance of ion selectivity, proton conductivity, and chemical stability in membrane design. Bipolar plates are essential components of RFBs, providing electrical connections, mechanical stability, and electrolyte distribution. They must have good mechanical stability, high electrical conductivity, and resistance to acidic environments. Metallic bipolar plates, graphitic bipolar plates, and carbon polymer composite bipolar plates are discussed, with their advantages and disadvantages compared. The review also addresses the challenges in RFB development, such as electrolyte leakage, corrosion, and fouling, and proposes mitigation strategies. The study emphasizes the need for further research to improve the performance and scalability of RFBs, particularly in metal-based systems. The findings suggest that advanced membrane materials and bipolar plate designs can significantly enhance the efficiency and reliability of RFBs for large-scale energy storage applications.A comprehensive review of metal-based redox flow batteries: progress and perspectives Redox flow batteries (RFBs) are considered a leading technology for large-scale energy storage, integrating with intermittent renewable energy sources like wind and solar to overcome the limitations of conventional storage systems. Recent advancements have focused on improving energy efficiency, longevity, and cost-effectiveness of RFBs. The review highlights key developments, current trends, and research gaps in metal-based RFBs, including their components, performance, and challenges. It provides a detailed analysis of the cost, associated challenges, and mitigation strategies of RFBs, along with a table comparing electrode/electrolyte materials for quick reference. RFBs are electrochemical cells that convert chemical energy into electrical energy through redox reactions in the electrolyte. They offer advantages over conventional batteries, such as separable components, higher energy storage capacity, and design flexibility. Vanadium redox flow batteries (VRFBs) are widely used due to their high energy density and long-term performance. However, organic redox flow batteries (ORFBs) are also gaining attention for their potential in sustainable and cost-effective energy storage. The review discusses the main components of RFBs, including membranes, bipolar plates, electrodes, and electrolytes. Membranes play a critical role in separating electrolytes and controlling ion exchange. Different types of membranes, such as ionic exchange membranes, porous separators, and composite membranes, are analyzed for their performance in RFBs. The review highlights the importance of ion selectivity, proton conductivity, and chemical stability in membrane design. Bipolar plates are essential components of RFBs, providing electrical connections, mechanical stability, and electrolyte distribution. They must have good mechanical stability, high electrical conductivity, and resistance to acidic environments. Metallic bipolar plates, graphitic bipolar plates, and carbon polymer composite bipolar plates are discussed, with their advantages and disadvantages compared. The review also addresses the challenges in RFB development, such as electrolyte leakage, corrosion, and fouling, and proposes mitigation strategies. The study emphasizes the need for further research to improve the performance and scalability of RFBs, particularly in metal-based systems. The findings suggest that advanced membrane materials and bipolar plate designs can significantly enhance the efficiency and reliability of RFBs for large-scale energy storage applications.