Composite proton exchange membrane with balanced proton conductivity and swelling ratio improved by gradient-distributed POSS nanospheres

A proton exchange membrane with high proton conductivity and stability is critical to high power density and durability for proton exchange membrane fuel cells (PEMFC). To balance the“trade-off”effect between proton conductivity and swelling ratio of sulfonated poly (arylene ether sulfone) (SPAES) based PEMs, a series of SPAES composite membranes with the gradient-distribution of polyhedral oligomeric silsesquioxane (POSS) nanospheres were fabricated via UV radiation process. Numerous POSS nanospheres act as reactive interfacial modifiers, and the moieties of hydrophobic POSS are immobilized into SPAES matrix with an ordered manner, which results in extremely low swelling ratio (1.0%) and maintains high proton conductivity (0.09 S/cm) under fully hydrated states at 80 °C for POSS/S50. This work provides a new approach to fabricate large-size composite membranes with a gradient structure for PEMFCs, and a reference for the other functional membranes related researches such as batteries and filtrations.