Nafion/sPOSS hybrid membranes for PEMFC. Single cell performance and electrochemical characterization at different humidity conditions

This work describes the preparation of hybrid membranes using octaphenyl polyhedral oligomeric silsesquioxane Ph8Si8O12 (POSS), either partially sulfonated (30%) or non-sulfonated as a filler and Nafion as polymer matrix. The membranes have been evaluated in terms of thermal stability (TGA, DSC), water uptake and ex situ in-plane proton conductivity. Morphology has been investigated using SEM and AFM. The hybrid membranes were electrochemically characterized into single cells in order to determine in situ through-plane proton conductivity, hydrogen crossover and cell performance. The analysis was made at 80 °C cell temperature, atmospheric pressure and different levels of relative humidity. The results showed the potential applicability of these membrane materials as electrolytes in PEMFC at medium/low humidity conditions.