Systematic Analysis of Cation Stability in Alkaline Exchange Membrane Fuel Cells

摘要

Improving long-term cation stability in alkaline environment is crucial for adopting anion exchange membrane (AEM) fuel cells as a commercially viable technology in clean energy applications. To reliably identify the most stable cation structures, we analyzed the cation stability of various synthetically prepared quaternary ammonium (QA) organic molecules via a simple silver oxide ion exchange reaction. With this method we were able to compare the stability of various structures of QA hydroxide in water without excess alkaline solution or inconsistencies faced in the presence of polymer backbones. By quantitatively comparing cation degradation via NMR, we were able to identify several cation structures with greater stability as compared to the most well-known benzyltrimethylammonium. From this study we concluded that alkyl-substituted cations seem to impart greater stability than benzylic-substituted cations in the presence of hydroxide anion in aqueous solution.