TY - JOUR
T1 - Imidazole based ionenes, their blends with PBI-OO and applicability as membrane in a vanadium Redox flow battery
AU - Strużyńska-Piron, Izabela
AU - Jung, Mina
AU - Maljusch, Artjom
AU - Conradi, Oliver
AU - Kim, Sangwon
AU - Jang, Jong Hyun
AU - Kim, Hyoung Juhn
AU - Kwon, Yongchai
AU - Nam, SukWoo
AU - Henkensmeier, Dirk
PY - 2017/11/1
Y1 - 2017/11/1
N2 - 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 °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.
AB - 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 °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.
KW - 2-Mesityl-benzimidazole
KW - anion exchange membrane (AEM)
KW - Ionenes
KW - PBI-OO
KW - Vanadium Redox Flow Battery (VRFB)
UR - http://www.scopus.com/inward/record.url?scp=85030091206&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85030091206&partnerID=8YFLogxK
U2 - 10.1016/j.eurpolymj.2017.09.031
DO - 10.1016/j.eurpolymj.2017.09.031
M3 - Article
AN - SCOPUS:85030091206
SN - 0014-3057
VL - 96
SP - 383
EP - 392
JO - European Polymer Journal
JF - European Polymer Journal
ER -