The Chemours Company
Flow battery having a separator membrane comprising an ionomer

Abstract:

The invention relates to flow batteries having improved crossover resistance to electroactive species, excellent coulombic and voltage efficiency and durability, which batteries comprise a separator membrane comprising an ionomer having a high equivalent weight, EW, to achieve these performance benefits. The ionomer has an EW of 1150 to 2000. Preferably, the ionomer is a perfluorosulfonic acid ionomer which has substantially all of the functional groups being represented by the formula --SO.sub.3X wherein X is H, Li, Na, K or N(R.sup.1)(R.sup.2)(R.sup.3)(R.sup.4) and R.sup.1, R.sup.2, R.sup.3, and R.sup.4 are the same or different and are H, CH.sub.3 or C.sub.2H.sub.5. Preferably, substantially all of the functional groups are represented by the formula --SO.sub.3X wherein X is H.