STUDIES ON MEMBRANE FOR REDOX FLOW BATTER Y .8. POLYOLEFIN BASED CATION-EXCHANGE MEMBRANE FOR VANADIUM REDOX FLOW BATTERY

Chlorosulfonated polyolefin dense thin homogeneous and composite asymm etrical cation exchange membranes were tested as separators for all-Va nadium redox flow battery. The chlorosulfonation was carried out under the environment of SO2Cl2 and N2 in the ratio of 1:4, under the irrad iation of light from 500 W ultra-high pressure mercury lamp by 20 000 lx, at room temperature and atmospheric pressure, after the method pro posed by de Korosy. As for dense thin homogeneous membrane 20 mum, the area resistivity measured in 2M KCl aqueous solution decreased with t he increase of chlorosulfonation period, from 3 kOMEGA.cm2 at 0 min. t o 0.24 OMEGA.cm2 at 120 min.. As for the asymmetric membranes 20 mum d ense polyethylene film laminated on porous polyethylene film of 200 mu m in thickness, 50% in porosity and 0.05 mum in pore diameter, the are a resistivity decreased from 3 kOMEGA.cm2 at 0 min. and passes through the minimum value of 1.50 OMEGA.cm2 at 30 min. and then increased wit h the increase of chlorosulfonation period. The area resistivity measu red in VOSO4 in H2SO4 aqueous solution decreased from about 4 OMEGA.cm 2 to 3 OMEGA.cm2, with the increase of the state of charge (SOC) for b oth homogeneous membranes, 15, 30, 45, 60 and 90 min. chlorosulfonatio n and asymmetric 15, 30, 60 and 90 min..