Effect of Ammonium Ion Structures on Properties of Alkaline Exchange Membrane Fuel Cells

Abstract

To investigate how quaternary ammonium ion structure affects the membrane stability and conductivity property of alkaline exchange membrane (AEM), we synthesized a series of polysulfones (PSUs) functionalized with various ammonium hydroxide groups. Ammonium ions with different steric environments were prepared by our recently developed Suzuki cross-coupling reactions of borylated polysulfone. We used two different synthetic strategies for the final polymers: In path A, like a general process for AEMs amine functional groups are first introduced to the PSU and quarternized afterward. In path B, pre-quarternized ammonium ions are directly introduced to the PSU.

Novel Synthetic Approach and their Properties for Alkaline Exchange Polysulfone Membranes

“…They are also conducted under mild conditions and produce negligible change in chain length or polydispersity index from those of the starting material. The combination of these two reactions in polymer functionalization allows us to easily control the following three parameters independently: (1) molecular weight of the functionalized polymer by choosing a starting polymer with desired molecular weight range, (2) the percentage of functional groups by adjusting relative amount of boron reagent during the C-H borylation, (3) the structure of incorporated functional group by choosing appropriate bromoaryl compounds that already have desired functional group [6].…”