Enhanced anhydrous proton conductivity of SPEEK/IL composite membrane embedded with amino functionalized mesoporous silica

The novel SP/IL/AMS composite membrane doped with amino-functionalized mesoporous silica (AMS) was successfully prepared. Sulfonated poly ether ether ketone (SPEEK, SP) was used as the polymer matrix and the ionic liquid (IL) was N-ethylimidazolium trifluoromethanesulfonate (EIm[Tfo]). Its properties were compared with SP/IL/NMS composite membrane doped with non-functionalized mesoporous silica (NMS). Fourier transform infrared spectroscopy (FT-IR) analysis indicated that the components in the composite membrane were bound by intermolecular forces. In addition, an acid-base interaction was formed between -NH2 in AMS and -SO3H in SPEEK. The acid-base pair is beneficial to proton conduction. The anhydrous proton conductivity of SP/IL/3-AMS-7.5 composite membrane is about 4 times higher than that of the SP/IL/NMS-7.5. In addition, the good interfacial compatibility between AMS and polymer matrix is conducive for creation continuous proton transfer channel. Thermogravimetric analysis (TG) showed that all composite membranes were stable at 270 degrees C. The leaching of IL data indicated that IL can be effectively retained due to the presence of -OH and -NH2 on the NMS and AMS surfaces. The SP/IL/AMS composite membrane could be used in proton exchange membrane fuel cells under medium temperature and anhydrous conditions. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.