Progress and directions in low-cost redox-flow batteries for large-scale energy storage

Compared to lithium-ion bateries,redox-low bateries have atracted widespread atention for long-duration,large-scale energy-storage applications.his review focuses on current and future directions to address one of the most signiicant challenges in energy storage:reducing the cost of redox-low batery systems.A high priority is developing aqueous systems with low-cost materials and high-solubility redox chemistries.Highly water-soluble inorganic redox couples are important for developing technologies that can provide high energy densities and low-cost storage.here is also great potential to rationally design organic redox molecules and ine-tune their properties for both aqueous and non-aqueous systems.While many new concepts begin to blur the boundary between traditional bateries and redox-low bateries,breakthroughs in identifying/developing membranes and separators and in controlling side reactions on electrode surfaces also are needed.