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Enhanced chemical and mechanical stability of ultra-thin Aemion+® over first generation Aemion® in anion exchange membrane fuel cells.

The crystal structures are reported for two unsubstituted arylnaphthalene lactones, 4-phenylnaphtho[2,3-c]furan-1(3H)-one (2), 9-phenylnaphtho[2,3-c]furan-1(3H)-one (3) and a non-aromatic dihydro arylnaphthene lactone, 3a,4-dihydro-9-phenylnaphtho[2,3-c]furan-1(3H)-one (5). There are only minor differences in the geometrical parameters of these structures. However, in certain cases, both isomers of arylnaphthalene lactones (termed Type I and Type II) were found in the same asymmetric unit cell.

In order to understand the electronic contribution of the thienopyrazine building block on the electronic properties of π-conjugated systems, small molecules containing thiophene and thienopyrazine moieties are synthesized and jointly studied by theoretical (DFT) and experimental methods (UV-Vis, UPS). Taking advantages of these preliminar attractive results, four low band gap extended structures have been elaborated on the base of Donor-Acceptor-Donor sequences (DAD); these elongated π-conjugated molecules exhibit noticeable electronic and absorption properties spreading from the near UV to NIR regions.

This work reports the permselectivity of an ionene-based anion exchange membrane – ionenes are a class of polymer in which cationic charged groups are located directly on the polymer backbone, as opposed to being pendant. The ionone studied, in the form of commercially available Aemion® anion exchange membranes, is based on hexamethyl-p-terphenyl poly (bibenzimidazolium) (HMT-PMBI), which has been explored in several electrochemical devices, yet their transport numbers, permselectivity, and through-plane conductivity, have not been reported. Measurement of transport properties was carried out on membranes (AF1-HNN8-25, AF1-HNN8-50, AF1-HNN5-25, AF1-HNN5-50) of varying ion exchange capacity and thickness, using the static method in which inherent experimental errors due to liquid junction potentials were elucidated and circumvented. Permselectivity, area specific conductance, and conductivity of Aemion® AEMs are correlated using their fixed charge group concentration. Due to its low water content and high fixed group concentration, the permselectivity of AF1-HNN5-X is higher than AF1-HNN8-X AEMs, despite the latter's higher IEC, but its ionic resistance is lower. Thicker AEMs were confirmed to be more permselective, which can be explained by their relatively lower water content and consequently higher fixed charge group concentration. The permselectivity, area specific conductance, and permselectivity to resistance ratio (α/R) of Aemion® AF1-HNN5-50 were found to be comparable to Selemion AMV, a common anion exchange membrane. The permselectivity/resistance (α/R) value of AF1-HNN8-25 was three times higher than Selemion AMV by virtue of its high ionic conductance.

Alkaline anion exchange membranes (AAEMs) which are capable of conducting hydroxide ions have been investigated in various alkaline based electrochemical energy storage and conversion technologies. Electrochemical systems relying on alkaline-based active components possess unique advantages over their acidic counterparts but at the same time are associated with significant challenges. In our research, we have been investigating C2-protected polybenzimidazolium and polyimidazolium polymers as hydroxide ion conducting polymers, for membranes and ionomer in catalyst layers, because of their stability in caustic conditions, scalability in synthesis, and mechanical strength. As an example of this work, we report on the performance of C2-protected hexamethylterphenyl-polybenzimidazole-based fuel cells in which the content and surface of the carbon support in the cathode catalyst layer is functionalized. We demonstrate that the composition of the cathode catalyst layer plays a large role in determining the performance of these particular anion exchange polymers.