Struzynska-Piron, Izabela Jung, Mina Maljusch, Artjom Conradi, Oliver Kim, Sangwon Jang, Jong Hyun Kim, Hyoung-Juhn Kwon, Yongchai Nam, Suk Woo Henkensmeier, Dirk 2024-01-20T00:04:15Z 2024-01-20T00:04:15Z 2021-09-03 2017-11 0014-3057 https://pubs.kist.re.kr/handle/201004/122114 A new cationic ionene was synthesised from dibromoxylene and 2-(2,4,6-trimethylphenyl)benzimidazole. Even though the weight average molecular weight Mw reached values around 40,000 g/mole, no membranes could be prepared from this ionene, probably because of its rigid backbone. Blending with 33, 41 and 50 wt% PBI-OO gave access to self-supporting membranes. In comparison with pure PBI-OO, these membranes have a higher water uptake (30-50%) and show a chloride conductivity around 0.5 mS/cm at 60 degrees C. In the VRFB, the membranes absorb sulfuric acid, which increases the conductivity. Nevertheless, the voltage efficiency (VE) of PBI-OO was surprisingly low. Further analysis suggests that the polymer gets easily sulfonated, leading to ionic crosslinking and thus reduced conductivity. At OCV, the PBI-OO based membrane showed a very low potential degradation rate of 0.19 mV/h even over 280 h, while the OCV decreased 60% within 60 h for Nafion 212. Charge/discharge curves revealed that the coulomb efficiency (CE) decreases with increasing amount of the ionene, while the VE increases. This indicates a potential for improved membranes by blending PBI or its derivatives (responsible for high CE) with highly conducting ion exchange materials to increase the VE in comparison to the pure polymer. English PERGAMON-ELSEVIER SCIENCE LTD Imidazole based ionenes, their blends with PBI-OO and applicability as membrane in a vanadium Redox flow battery Article 10.1016/j.eurpolymj.2017.09.031 1 EUROPEAN POLYMER JOURNAL, v.96, pp.383 - 392 EUROPEAN POLYMER JOURNAL 96 383 392 N scie scopus 000414887700033 2-s2.0-85030091206 Polymer Science Polymer Science Article ANION-EXCHANGE MEMBRANES POLYBENZIMIDAZOLE MEMBRANES COULOMBIC EFFICIENCY DEGRADATION STABILITY POLYMER Vanadium Redox Flow Battery (VRFB) anion exchange membrane (AEM) PBI-OO Ionenes 2-Mesityl-benzimidazole