Publication Details (including relevant citation information):
Mohanty, A.D. and Bae, C., Mechanistic Analysis of Ammonium Cation Stability for Alkaline Exchange Membrane Fuel Cells, J. Mater. Chem. A, 2014, 41, 17189
Improving long-term cation stability is crucial for adopting anion exchange membrane fuel cells as a
commercially viable technology in clean energy conversion applications. To reliably identify the most
stable cation structures, we analyzed the cation stability of various synthetically prepared quaternary
ammonium organic molecules via a silver oxide ion exchange reaction. This method enabled us to
compare the stability of various structures of quaternary ammonium hydroxide in pure form 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 three cation structures
with greater cation stability than the most well-known benzyltrimethylammonium. In addition, we were
able to elucidate byproduct formation and degradation mechanisms as a result of hydroxide attack.
From this study we concluded that alkyl-substituted cations seem to impart greater stability than
benzylic-substituted cations in the presence of hydroxide anions in aqueous solution.