Sulfonated Beta Zeolite/Sulfonated Poly(Ether Ether Ketone) as Proton Exchange Membrane for Vanadium Redox Flow Battery: Proton Conductivity and Vanadium Ion Permeability Assessment
Intan Elvina, Krisada Kampanatsanyakorn, Piriyathep Kanchanadul, Anuvat SirivatABSTRACT
A paramount and important component that determines the vanadium redox flow battery (VRFB) performances is the proton exchange membrane (PEM). Poly(ether ether ketone) (PEEK) is a promising candidate which is developed as a PEM for VRFB. Aiming to elevate the proton conductivity of the PEM, PEEK as the matrix phase was sulfonated to S‐PEEK by reacting with concentrated H 2 SO 4 . Beta zeolite, an aluminosilicate mineral with high surface area and Si/Al ratio and expected to improve both proton conductivity and thermomechanical stabilities, was modified to sulfonated Beta zeolite (S‐BETA). S‐BETA was embedded into S‐PEEK at various volume fractions and casted in petri dish. The membrane properties were evaluated primarily in terms of proton conductivity and vanadium‐ion permeability. The 8% v/v incorporation of S‐BETA zeolite into S‐PEEK matrix exhibited the highest proton conductivity of 5.02 × 10 −2 ± 1.7 × 10 −3 S cm −1 relative to the pristine S‐PEEK and other composite membranes, as well as the improvement in the V 4+ ionic selectivity of 4.84 × 10 5 ± 2.4 × 10 3 cm 2 s −1 .