Journal of Membrane Science, Vol.573, 485-492, 2019
Acid resistant PVDF-co-HFP based copolymer proton exchange membrane for electro-chemical application
Acid resistant proton exchange membranes (PEMs) are synthesized from aliphatic highly hydrophobic polyvinylidene-co-hexafluoropropylene (PVDF-co-HFP) and aromatic hydrophilic sodium-p-styrene sulfonate at nanostructure level modification. Synthesized copolymer PEMs are analyzed for their chemical structure to confirm the presence of functional groups. Electrochemical characterizations are carried out in terms ion-exchange capacity, ionic conductivity and water content. Maximum IEC value 1.91 meq/gm is observed for PDSt-40 copolymer PEM with 1.58x10(-2) S/cm proton conductivity and 29.1% of water content. Vanadium ion permeability is also checked for copolymer membranes in terms of applicability for vanadium redox flow batteries. PDSt-40 copolymer PEM shows lowest value of VO2+ ion permeability 2.87x10(-7) cm(2) min(-1), which is about 40% less compared to Nafion membrane. Further all synthesized PEMs are checked for charging-discharging performance for single cell VRFB. PDSt-40 PEM shows better performance in term of columbic and voltage efficiency. Copolymer membranes found to be stable thermally and mechanically and also in harass condition with 18M H2SO4 for 24 h. Results indicate that synthesized copolymer PEMs can be a good candidate for electrochemical energy systems as well as high temperature applications.