Octa‐imidazolium POSS/quaternized polysulfone composite anion exchange membrane for alkaline fuel cell

In the present study, a series of new anion exchange composite membranes were fabricated from pre‐synthesized imidazolium grafted polyhedral oligomeric silsesquioxane (IM‐POSS) with quaternary polysulfone (QPSU). Synthesized IM‐POSS were acutely characterized by Fourier‐transform infrared, NMR, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) investigations to confirm the chemical structure and cubic morphologies. The IM‐POSS nanoparticles have binary function in the anion exchange membrane by providing more additional ion conducting groups (imidazolium) and by reinforcing the membrane in molecular level for overall improvement of composite membranes. The prepared composite membranes with various compositions of the IM‐POSS/QPSU were characterized by X‐ray diffraction, SEM, ion exchange capacity, water uptake (W_up), and conductivity to assure the appropriateness of their use as a solid alkaline electrolyte in anion exchange membrane fuel cell. The membrane electrode assembly was constructed using Pt anode (0.25 mg/cm²), Ag cathode (0.375 mg/cm²), and various IM‐POSS/QPSU composite membranes, which was tested in an in‐house built fuel cell setup. The membrane with 15% IM‐POSS showed the maximum power density of 309 mW/cm². The results showed that the addition of IM‐POSS is a straight forward and effectual method to enhance the hydroxide conductivity without sacrificing other properties of the membrane. POLYM. COMPOS., 40:1536–1544, 2019. © 2018 Society of Plastics Engineers