Lee, Yona Kim, Sangwon Maljusch, Artjom Conradi, Oliver Kim, Hyoung-Juhn Jang, Jong Hyun Han, Jonghee Kim, Jihyun Henkensmeier, Dirk 2024-01-19T20:02:07Z 2024-01-19T20:02:07Z 2021-09-02 2019-06 0032-3861 https://pubs.kist.re.kr/handle/201004/119963 1-(6-bromohexyl)-3-methyl-2-(2,4,6-trimethylphenyl)-2H-benzimidazolium bromide was synthesised and grafted onto polybenzimidazole (PBI). The highest obtained degrees of functionalisation were 0.7 and 1.1 ionic groups per repeat unit, corresponding to ion exchange capacities of 1.25 and 1.55 mmol chloride/g. While the latter material had much reduced tensile strength and Young's modulus, the material with a lower degree of functionalisation showed properties similar to PBI and was therefore further investigated. X-ray scattering showed that the functional group reduced the crystallinity. Conductivity was in the range of 2-3 mS cm(-1,) but increased to 23 mS cm(-1) after doping in 2 M sulfuric acid, 2-4 times higher than for doped PBI. Permeability for VO2+ ions was 0.8 x 10(-12) m(2) s(-1). In the vanadium redox flow battery, the grafted PBI showed higher coulomb and voltage efficiency than PBI, and therefore also higher energy efficiency. English ELSEVIER SCI LTD Polybenzimidazole membranes functionalised with 1-methyl-2-mesitylbenzimidazolium ions via a hexyl linker for use in vanadium flow batteries Article 10.1016/j.polymer.2019.04.048 1 POLYMER, v.174, pp.210 - 217 POLYMER 174 210 217 N scie scopus 000469028200026 2-s2.0-85065853290 Polymer Science Polymer Science Article ANION-EXCHANGE MEMBRANES BLEND MEMBRANES PBI-OO STABILITY EFFICIENCY Vanadium redox flow battery (VRFB) Polybenzimidazole 2-Mesityl benzimidazolium