Nanoscience and Microsystems ETDs

Publication Date

Fall 12-14-2020

Abstract

Membrane chemical degradation is one of many factors that can impact fuel cell durability. The fuel cell’s performance and lifetime heavily depends on the membrane and its ability to maintain chemical and mechanical integrity. In Nafion® membranes, hydroxyl radicals are the primary cause of chemical membrane degradation as they attack the membrane’s polymer structure. Radical formation can ensue via peroxide decomposition at the cathode or gases reacting on Pt particles or contaminants like Fe (a fenton's reagent) within the membrane. As radicals attack the membrane’s polymer structure the membrane thins, and fluoride and sulfate ions are released. This consequently causes mechanical failures to transpire, e.g. cracks, tears, perforations and pinhole formation, leading to an increase in membrane degradation and a decrease in fuel cell performance. Though the membrane has been investigated extensively under various operating conditions, there has not been any research on the correlation between electrode composition (Pt loading, carbon type, ionomer content and thickness) and degradation. This is critical as the Pt loadings are being reduced to achieve targets for commercialization. The focus of this research is to probe membrane degradation for MEAs with ultra-low Pt loadings (i.e. ≤ 0.1 mgPt cm-2) at each electrode to contribute to existing knowledge of membrane degradation mechanisms.

Document Type

Dissertation

Degree Name

Nanoscience and Microsystems

Level of Degree

Doctoral

Department Name

Nanoscience and Microsystems

First Committee Member (Chair)

Fernando Garzon

Second Committee Member

Abhaya Datye

Third Committee Member

Lok-Kun Tsui

Fourth Committee Member

Rangachary Mukundan

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