Composite Proton Exchange Membrane Composition and Method of Preparation

A flow cell battery comprising:

• an electrochemical cell, the electrochemical cell comprising:
• a composite proton exchange membrane comprising
• a perfluorosulfonic acid (PFSA) resin, and
• an amino-functionalized polybenzimidazole (APBI);
• an anode;
• an anode current collector electrically connected to the anode;
• a first flow frame disposed between the composite proton exchange membrane and the anode current collector, the first flow frame defining a plurality of first flow channels;
• a first tank comprising an anolyte, the anolyte comprising V4+ and V5+;
• a first pump configured to flow the anolyte from the first tank into the plurality of first flow channels;
• a cathode;
• a cathode current collector electrically connected to the cathode;
• a second flow frame disposed between the composite proton exchange membrane and the cathode current collector, the second flow frame defining a plurality of second flow channels;
• a second tank comprising a catholyte, the catholyte comprising V2+ and V3+;
• and
• a second pump configured to flow the catholyte from the second tank into the plurality of second flow channels.