Preparation and properties of amphoteric ion exchange membrane for all vanadium redox flow batteries

The amphoteric ion exchange membrane basing on cheap polyetheretherketone (PEEK) engineering plastics was prepared by modification reactions and casting method in this investigation. The membrane was characterized by Fourier transformer infrared and thermogravimetric analysis. The IEC and sheet resistance of the membrane were also measured. The energy efficiency was tested by an experimental application device. Results show that the sulfonic acid and quaternary ammonium groups are introduced into the molecule chain successfully. The membrane has good thermal stability and IEC as high as 2.58 mol/kg, and the sheet resistance of which is 0.11 Ω/cm2. The energy efficiency of the membrane is 74.87%. The good properties and low price of the product in this investigation imply the large scale potential applications in VRFBs.