Poly(arylene ether sulfone) with tetra(quaternary ammonium) moiety in the polymer repeating unit for application in solid alkaline exchange membrane fuel cells

Poly(arylene ether sulfone)s with tetra(quaternary ammonium) hydroxide groups in the repeating unit of the polymer main chain were prepared for solid alkaline exchange membrane fuel cells. We synthesized a novel monomer with four amine groups which were derivatized to ammonium functional groups. Using this monomer, we easily synthesized poly(arylene ether sulfone)s which conduct hydroxyl ions. This direct synthetic method can control the exact amount of quaternary ammonium hydroxide groups in the polymer structure. The polymers were characterized by NMR, thermogravimetric analysis, water uptake, conductivity, and cell performance. In a solid alkaline exchange membrane fuel cell test, a maximum power output of 77 mW cm−2 was achieved using hydrogen and oxygen.