Membranes for Redox-Flow-Batteries (RFB)

The redox-flow-battery (RFB) systems are complementary devices for pairing of the green electricity production with energy storage systems in range between 100kWh and 1.000 MWh. The RFBs are facilitating frequent load changes on input while featuring easy maintenance, scalability, robust operation parameters and very advantageous CAPEX for its longevity. The key part of the system is the membrane that determines the efficiency of the process. The main portion of RFB installations is built with vanadium redox-flow-battery (VRFB). The VRFB are based on electrolyte made from water-soluble vanadium sulfate species. The vanadium charge bearers are separated by a membrane that also transports the released counterpart of vanadium ions. Depending on the system, one can use either cation-exchanged membranes transporting protons and featuring high power density or anion-exchanged membranes transporting sulfate ions and featuring easy management and high efficiency.