Development of SPEEK-based proton exchange membrane for fuel cell applications

• Main Author: Tan, Wei Tian
• Other Authors: Chan Siew Hwa
• Format: Final Year Project
• Language: English
• Published: 2015
• Subjects: DRNTU::Engineering::Mechanical engineering
• Online Access: http://hdl.handle.net/10356/64017
• Institution: Nanyang Technological University

This project aims to investigate the possibility of improving the physical and chemical properties of the SPEEK membranes by modification via cross-linkage. Currently, the most used material for Proton-Exchange Membrane(PEM) fuels cells is Nafion 117 which has excellent thermal and mechanical stability. However, it is costly to use Nafion 117 as the cell membranes and cheaper alternatives such as Sufonated Poly(EtherEtherKetones) ( SPEEK) are looked into as possible substitute. Despite being cheaper, the proton conductivity of SPEEK membranes is lower than Nafion 117 membranes. In this project, we would be developing SPEEK-based composite membranes with silica particles using different methods and compare the best sample with Nafion 117. The first method is by blending (3-mercaptopropyl) trimethoxysilane (MPTMS) with SPEEK and then oxidizing MPTMS with hydrogen peroxide (H2O2). The other method is by modifying fumed silica with MPTMS and then oxidizing by H2O2 before adding it to SPEEK membranes. For each method, we had developed 4 samples with varying concentrations of the silicon-containing compounds and a pure reference sample. After fabrication of the composite membrane samples, we would investigate the proton conductivity, water uptake rates, swelling rates, tensile strength, Fourier Transform Infrared (FTIR) spectroscopy test and the Field Emission Scanning Electron Microscope (FESEM) images of these membranes. From the 2 groups of samples, we had found that the increasing concentration of silica increases the swlling rates for both groups of samples but show contradicting trends for both mechanical strength and proton conductivity. In the FTIR results, it indicates the presence of SPEEK, silica particles and possible contamination. Lastly, the FESEM shows that the silica particles in MPTMS/SPEEK samples are more packed than Silica/SPEEK samples. From the experiment's results, the first method be considered the better method to develop PEM.