Highly durable poly(arylene piperidinium) composite membranes modified with polyhedral oligomeric silsesquioxane for fuel cell and water electrolysis application

The increase in demand for green-hydrogen and the fast development of electric vehicles underpin the increased focus on research regarding water electrolysis and fuel cell system. One of them is the fabrication of sustainable and high ion-conductive electrolyte membranes adapted to the requirements of the global market. In this study, a series of composite membranes consisting of poly(arylene piperidinium), an ion conductor, and surface-modified polyhedral oligomeric silsesquioxane (POSSI), an intensified nanoparticle, were fabricated by the solution casting method. It was observed that the hydration properties and chemical stability of the composite electrolyte significantly improved while the anion conductivity of PAP100-POSSI5.0 membrane slightly increased due to the presence of crosslink bonding between the polymer and POSSI as well as the unique structure of the POSSI nanoparticle. During the polarization of alkaline fuel cell and water electrolysis of prepared membranes, the maximum power density of PAP100-POSSI5.0 membrane was 152.37 mW cm −2 , which was 3-fold higher than that of pristine PAP100-dimethyl membrane, whereas the overpotential of PAP100-POSSI5.0 membrane at 700 mA cm −2 was 1.72 V. This value was significantly lower than that of FAA-3-PK-140 membrane (2.68 V) at 50 °C in 1 M KOH solution. • Membranes between poly(arylene piperinium) and modified POSS was prepared. • Modified POSS could improve chemical stability of composite electrolyte membrane. • The hydration property of membrane was improving by the crosslink network. • PAP100-POSSI5.0 showed high alkaline fuel cell and water electrolysis performance.