30 μm thin hexamethyl-p-terphenyl poly(benzimidazolium) anion exchange membrane for vanadium redox flow batteries

From polybenzimidazoles to polybenzimidazoliums and polybenzimidazolides

“…cationic vanadium species has triggered substantial interest in this electrolyte system for redox flow battery applications recently. [12][13][14][17][18][19] For many years, m-PBI-H3PO4 has been considered the most technologically relevant electrolyte system, due to the lower vapor pressure and high thermal stability of H3PO4, which allows for high ion conductivity at low water activity and at temperatures up to 200 °C. 37 The conductivity is mediated by the excess acid within the structure and thus increases with increasing ADL.…”

“…3 During the last two decades, the application scope of PBIs has broadened significantly to extend far beyond the high-performance structural materials, as shown in Figure 1. In particular, functionalized PBI derivatives have been widely explored as electrolyte systems and separators in electrochemical devices such as acidic 4,5 or alkaline 6,7 fuel cells, water [8][9][10] or sulfur dioxide 11 electrolyzers, flow batteries, [12][13][14][15][16][17][18][19] lithium metal 20 or ion 21 batteries, hydrogen sensors, [22][23][24] actuators 25 as well as electrochemical hydrogen purification 26,27 and compression 28,29 units.…”

Performance and stability comparison of Aemion™ and Aemion+™ membranes for vanadium redox flow batteries

“…Both precursor solutions were charged to generate both the positive and negative electrolyte solutions in the same manner as previously reported. 26 Swelling studies…”

“…Aemion™ is based upon the modied PBI ionomer, hexamethyl-p-terphenyl polybenzimidazolium (HMT-PMBI), which has previously been reported for VRFB. 26 In this work, we report a rst comparison of two commercial non-crosslinked membranes (Aemion and Aemion+) as 50 mm thick, bulk membranes and a 15 mm thin, reinforced Aemion+ membrane to possibly further reduce material cost and increase mechanical integrity.…”

Vanadium Redox Flow Batteries: A Review Oriented to Fluid-Dynamic Optimization

“…PBI membranes have been widely investigated in nanofiltration applications [77] and in high-temperature fuel cells [78]. PBI is able of absorbing acid and being protonated, developing anion exchange properties, as is the case of HMT-PBI [79], or for cation exchange, introducing sulfonic groups in the polymer structure [80]. PBI can also be built as an asymmetric porous membrane, see the work of Gubler et al [73].…”