membranes for batteries

The fumasep membrane is the new heart of a Redox Flow Battery. FUMATECH BWT GmbH produces both porous separators and nonporous functional anion- and cation-exchange membranes for various types of batteries. In VRFB one can find its right choice, whether aiming of high efficiency, high operation current density when high speed of charging is required or some compromise between the two modes.

Our porous membranes are characterized by lower cost and low specific area resistance but low selectivity and a potential risk of electrolyte transfer, however. Our non-porous ion-exchange membranes are advantageous as for their high coulomb efficiency and avoidance of any liquid transfer between both electrolytes. Cation-exchange membranes are primarily an impermeable, proton-conductive barrier to the electrolyte. As all of the RFB systems are based on cations of different oxidation state, a selective proton-conductive anion-exchange of high rejection towards other cations is the most optimum choice for maximum efficiency.