THESIS
2016
xiii, 162 pages : illustrations (some color) ; 30 cm
Abstract
Increasing precautions are taken and laws enforced against the energy crisis and global warming, leading to an increased trend in renewable and green energies in the recent years. Among the various types of clean energy production, Proton Exchange Membrane Fuel Cells (PEMFC) have garnered attention due to its chemical and thermal stability as well as high theoretical efficiency.
PEMFCs have two major problems that need to be solved before it can attain widespread use: water and heat management. As well as the two mentioned problems, PEMFC catalyst is also an area of high interest as a mean to improve the overall efficiency.
A novel architecture of the PEMFC membrane is suggested to allow the PEMFC to be effective without external humidification as well as to continue to operat...[
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Increasing precautions are taken and laws enforced against the energy crisis and global warming, leading to an increased trend in renewable and green energies in the recent years. Among the various types of clean energy production, Proton Exchange Membrane Fuel Cells (PEMFC) have garnered attention due to its chemical and thermal stability as well as high theoretical efficiency.
PEMFCs have two major problems that need to be solved before it can attain widespread use: water and heat management. As well as the two mentioned problems, PEMFC catalyst is also an area of high interest as a mean to improve the overall efficiency.
A novel architecture of the PEMFC membrane is suggested to allow the PEMFC to be effective without external humidification as well as to continue to operate at higher temperatures consisting of porous stainless steel substrate, zeolite thin layers and confined Nafion.
Zeolites are explored as a method to retain the water that is produced from the fuel cell reactions to self-humidify the membrane. MFI, FAU and LTA types of zeolites and various orientations were explored to improve its water retaining and self-humidifying properties, showing improvements under dry feed conditions that reached up to more than four times of the performance of commercial Nafion 117. (570mW/cm
2 vs 130mW/cm
2 at 50°C)
The confinement of the Nafion is another aspect that is studied. The interface between the Nafion and zeolite was observed under the focused ion beam to check for reorientations of the sulfonic groups of the Nafion that leads to improved proton conductivity as observed by the enhancement in performance. An optimum confinement volume of 246pL per Nafion plug inside the pores is suggested from the data.
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