Performance Studies and Analysis of Catalyst Coated Membrane Method within Membrane Electrode Assemblies of PEMFC
Date Issued
2008
Date
2008
Author(s)
Lai, Wen-Jeng
Abstract
This study focuses on the key part of Membrane Electrode Assembly (MEA) - proton exchange membrane fuel cell, and also includes the component of the MEA; the manufacture method of the MEA and the test results. In this work, MEA were fabricated by catalyst coated membrane (CCM) method, the catalyst (Pt/C) was applied on the surface of membrane directly to improve the continuity of interfaceetween the catalyst film and the membrane. To derive the best performance of MEA, the flow patterm needs to be verified by CFD software-FLUENT, the single serpentine type flow channel (channel width 1.6mm、deeth 1mm, rib width 1.35 mm) was chosen for the following tests. This study started from finding the way to improve the single-cell performance, according to the method of applying catalyst, amount of isopropyl alcohol, drying temperature, the presence of dry Nafion film and the relative humidity of inlet fuel. The results were verified by checking the overpotential curve (I-V curve), scanning electron microscope, cyclic voltammetry. Nafion212 was adopted as the membrane electrode assembly with an active area of 50 mm x 50 mm. The best performance of the home-made MEA was 0.29 W/cm2 at 0.64 V with power density of 450.12 mA/cm2, corresponding to the conditions as: Pt loading at cathode and anode side are both 0.6 mg/cm2, hydrogen and oxygen were at the same gas flow rate of 0.25 SLM, cell temperature at 70℃, and hydrogen andoxygen humidification temperature at 70℃. This study also introduced the design and manufacturing methods of a fuel cell stack. In this work, two cells were used to make a stack. The best output power was 0.53 W/cm2 at 1.2 V and 444.84 mA/cm2. The manufacture procedures in this study were different from others. We can find that some methods would improve the MEA performance. If we can make the procedure more general, or use less amount of material, then can reduce the fuel cell cost dramatically.
Subjects
proton exchange membrane fuel cell
membrane electrode assembly
catalyst coated membrane method (CCM)
Type
thesis
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