Double-Membrane Design for High-Voltage and Low- Crossover Redox Flow Batteries

Decoupling energy capacity and power delivery, redox flow batteries (RFBs) have great design flexibility and scalability, particularly suitable for the applications of renewable (e.g., wind and solar) electricity storage[1, 2]. As electrochemical devices, RFBs are also free from geographical or geologic limitations that are faced by the pumped hydro and the compressed air electricity-storage technologies. However, the generally low energy and power density of RFBs have been identified to be main drawbacks especially when compared with other battery systems, reducing the cost-effectiveness of RFBs. Increasing the solubility of electroactive species by choosing alternative redox pairs or using different electrolytes can theoretically increase the energy density, but leaving the power density unchanged. Improvin