On Various Hydrocarbon Ion Conducting Membranes for a Vanadium Redox Flow Battery

Several types of ion conducting membranes such as cation exchange membrane, anion exchange membrane, and amphoteric membrane with low vanadium co-ion crossover were evaluated for a vanadium redox flow battery. Three kinds of polymer electrolytes consisting of caion exchangable or anion exchangable or aphoteric functionals were introduced into porous hydrocarbon substrates and crosslink-polymerized by radical polymerization in this work.  The thickness of the prepared membranes was controlled between 20 and 25 micrometers to extremely lower membrane resistances. Finally, film-like polymer electrolyte membranes were prepared. To compare membrane property a cast type of caion exchange membrane was also prepared. The prepared four different types of pore-filling membranes and a cast membrane were examined to compare vanadium co-ion crossover through the membranes. Also, the physico-chemical properties of the prepared membranes such as swelling behavior, membrane area resistance were investigated to apply for charge-discharge performance in correlation with the electrolyte composition.