Synthesis and characteristics of aminated vinylbenzyl chloride-co-styrene-co-hydroxyethyl acrylate anion-exchange membrane for redox flow battery applications

We have synthesized a VBC-co-St-co-HEA copolymer using 4-vinylbenzyl chloride (VBC), styrene (St), and 2-hydroxyethyl acrylate (HEA) in order to manufacture anion-exchange membranes for all vanadium flow battery. Through the quaternarization and crosslinkage of vinylbenzyl chloride-co-styrene-co-hydroxyethyl (VSH) copolymer, anion-exchange membranes of the aminated VBC-co-St-co-HEA (AVSH) were manufactured. In order to find out the variation of the degree of crosslinking according to the amount of adipic acid as a crosslinking agent and to confirm the structure of the VSH and the AVSH copolymer, Fourier transform infrared (FT-IR) analysis was conducted, and also Differential scanning calorimetry (DSC) analysis was conducted in order to find out their thermal properties. The water uptake, anion-exchange capacity, electric resistance, and ionic conductivity of the AVSH anion-exchange membrane and the efficiency of an all vanadium redox-flow battery containing such an AVSH anion-exchange membrane were measured. The maximum water uptake, maximum anion-exchange capacity, the electric resistance, swelling and ionic conductivity of the AVSH anion-exchange membrane were 40.2%, 1.18 meq/g, 1.9 Ω cm2, 7.36% and 0.00351 S/cm, respectively. All vanadium redox-flow battery efficiency was measured and charge–discharge, voltage, energy efficiency were 95.2%, 74.9%, 75.3% and 89.6%, respectively.