Abstract
Ph.D. (Chemistry)
This work focused on fabrication of a series of quaternized poly (2.6 dimethyl – 1.4 phenylene oxide)/ polysulfone (QPPO/PSF) blend anionic exchange membranes (AEM) for alkaline fuel cell application. The anion exchange composite membranes were blended with different materials, (i) zinc oxide (ZnO), (ii) Graphene oxide (GO) and (iii) titanium dioxide (TiO2) then evaluated for feasibility in alkaline fuel cell application.
The characteristic properties of all membranes were investigated with X-ray diffraction (XRD), thermogravimetric analysis (TGA) and scanning electron microscope (SEM). The successful fabrication of the anion exchange membrane composite was confirmed by the FT-IR spectroscopy and proton nuclear magnetic resonance (1H NMR). Anion exchange properties such as ion exchange capacity (IEC), water uptake (WU), ion conductivity (IC) and methanol permeability were also evaluated.
The anion exchange membrane (AEM) to be used for alkaline fuel cell should be chemically stable under alkaline working condition. Therefor the membranes alkaline stability was investigated by immersing them in a 3 M NaOH solution followed by evaluation of ion conductivity for a period of 10 days at room temperature. The best performing membrane was further evaluated at 80 °C. The composite membranes were evaluated in a direct methanol fuel cell by preparing a membrane electrode assembly (MEA). The cell was assembled by using a Pt on carbon cloth as the cathode, and the anode side Pt on the surface of nickel foam was used. A catalyst loading of 2 mg.cm-2 was used for all MEA, both on the anode and cathode side.
The series of quaternized poly (2,6 dimethyl – 1,4 phenylene oxide)/ polysulfone (QPPO/PSF) blend membranes (virgin membrane) were found to have an IEC of 1.75 – 2.18 mmol.g-1, WU of 77 – 111.3 %, and surface IC of 0.76 – 2.4 mS.cm-1 at room temperature. The best performing membrane was then chosen to be used for...