Pathways to High-Power-Density Redox Flow Batteries

Redox flow batteries (RFBs) promise to fill a crucialmissing linkin the energy transition: inexpensive and widely deployable grid andindustrial-scale energy storage for intermittent renewable electricity.While numerous lab-scale and demonstration-scale RFBs have been delivered,widespread commercial deployment is still limited by high electrolyte,stack, and balance of plant capital costs. Increasing the power densityof RFBs is correlated with lower stack costs, primarily because thearea needed for expensive electrode and membrane components to reacha target power density is reduced. In the present contribution, wesummarize the areal power densities reported for lab-scale RFBs, criticallyevaluate major pathways employed for power optimization, and identifyopportunities for developing yet-higher power density systems.