| 초록 |
We report herein that poly(2,5-benzimidazole) (ABPBI) membranes can be applied to vanadium redox flow batteries (VRFBs) with outstanding performance by controlling crystallinity of ABPBI. ABPBI was prepared by the polycondensation of 3,4-diaminobenzoic acid (DABA), and N-substitution of ABPBI was synthesized with different substitution ratios of 1-Bromo-3-methylbutane. Through wide angle X-ray scattering, it was conformed that the crystallinity of substituted ABPBI membrane was gradually changed from crystal to amorphous structures with increasing substitution ratio owing to suppressing chain packing. As the substitution ratio increases, ABPBI membrane with amorphous structure showed higher water and sulfuric acid absorption property, and exhibited lower area resistance than ABPBI membranes with crystal structure. More importantly, the VRFB with ABPBI-50 showed outstanding cycling performance with stable operation during 500 charge-discharge cycles |
