Perfluorinated Membranes and Improved Electrolytes for Redox Cells and Batteries

A redox cell having a positive half cell, a negative half cell, a positive half cell solution and a negative half cell solution further comprising:

• a perfluorinated ionically conducting membrane located between the positive half cell and the negative half cell and in contact with the positive half cell solution and the negative half cell solution wherein the membrane has a thickness of between 0.5 to 5 mil;
• an acid capacity of between 0.5 and 2 meq/g;
• a conductivity at 25° C. of between 0.01 and 1 S/cm;
• a water uptake of between 30% and 70% at 100° C. for 1 hour;
• a tensile strength of between 20 and 60 MPa in both directions when water soaked at 23° C.;
• a linear expansion of less than 8% from 50% Relative Humidity at 23° C. to water soaked at 23° C. in both directions;
• a melting point ranging from 180 to 240° C., wherein the perfluorinated membrane is produced by casting from a solution of a resin selected from a group consisting of a resin that has an Equivalent Weight (EW) of between 800 and 1100 grams resin per equivalent SO3− and a resin having an ion exchange capacity of between 1.25 and 0.91 milliequivalents SO3− per gram resin.