Synthesis of (Si-PWA)-PVA/PTFE high-temperature proton-conducting composite membrane for DMFC

摘要

The inorganic silica immobilized PWA based (Si-PWA)-PVA/PTFE composite membrane was developed by an amalgamation of pore filling and layer by layer (LBL) casting. The composition of the top layer was optimized to be 0.3 M PWA: 0.2 M TEOS: 0.15PVA concerning to proton-conductivity and methanol permeability of the membrane. Surface morphological studies and elemental analysis were carried out by using SEM-EDX. The FT-IR and XRD analysis had confirmed the intercalation of sol with PTFE. Thermal deformation of the membrane was studied by TGA and it is stable up to 180 degrees C. Ion exchange capacity and water uptake were determined to be 2.38 meq per gram and 21.7%. The membrane has exhibited maximum proton conductivity of 41.2 mS cm(-1) at 100 degrees C. The membrane has significantly lower methanol permeability of 3.2 x 10(-7) cm(2) S-1 compared to that of Nafion117 (7.9 x 10(-7) cm(2) S-1) at 28 degrees C and the same trend was observed at 40, 60, and 80 degrees C. The (Si-PWA)-PVA/PTFE composite membrane is showed enhanced proton conductivity and lower methanol permeability at elevated temperatures. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.