Membranes for all vanadium redox flow batteries

Battery storage systems become increasingly more important to fulfil large demands in peaks of energy consumption due to the increasing supply of intermittent renewable energy. The vanadium redox flow battery systems are attracting attention because of scalability and robustness of these systems make them highly promising. One of the Achilles heels because of its cost is the cell membrane. Exposure of the polymeric membrane to the highly oxidative and acidic environment of the vanadium electrolyte can result in membrane deterioration. Furthermore, poor membrane selectivity towards vanadium permeability can lead to faster discharge times of the battery. These areas seek room for improvement to increase battery lifetime. The high costs of the currently used membranes substantially contribute to the price of the vanadium redox flow battery systems. Therefore, the reduction of the cost of the membrane by using alternative materials can reduce the overall battery costs substantially, thereby increasing the prospects of the industrial use of these systems. In this report different membrane types are reviewed and the important factors determining membrane performance are analysed. An overview of potential new membranes is presented which could boost the performance of these systems in future and reduce costs substantially.