A novel proton exchange membrane with long-range ordered proton transport pathways through modulation of interfacial interactions via amino-functionalized polyhedral oligomeric silsesquioxane-grafted graphene oxide

Nano octa-aminopropyl polyhedral oligomeric silsesquioxane (OA-POSS) was grafted into graphene oxide (GO) via covalent bonding to synthesize OA-POSS-g-GO. A novel SP/OA-POSS-g-GO proton exchange membrane was prepared by adding sulfonated poly (ether ether ketone) (SPEEK, SP). OA-POSS was well dispersed on GO to form an ordered acid-base pair with SPEEK, which facilitated the construction of continuous ion channels. GO as a carrier facilitated the construction of long-range proton conduction pathways in the membrane. The strong interactions between OA-POSS and SPEEK along with the synergistic effect of GO modulate the size of ionic clusters and increased the bound water ratio within the membrane. The conductivity of the SP/OA-POSS-g-GO-2 membrane (80 degrees C, 95% RH) reached 0.2096 S center dot cm(-1), which was 1.7 times higher than that of the SPEEK membrane (0.1265 S center dot cm(-1)). The conductivity of the SP/OA-POSS-g-GO-2 membrane increased at 100 degrees C and 40% RH, while that of the SPEEK membrane decreased with the temperature increased above 80 degrees C. The maximum power density of the single cell assembled from the composite membrane reached 305.8 mW center dot cm(-2) at 80 degrees C and 95% RH, which was 1.4 and 1.3 times higher than that of the SPEEK and Nafion 117 membrane, respectively.