Date of Award

2018

Document Type

Open Access Dissertation

Department

Chemistry and Biochemistry

First Advisor

Brian C. Benicewicz

Abstract

After approximately 15 years of development, polybenzimidazole (PBI) chemistries and the concomitant manufacturing processes have evolved into commercially produced membrane electrode assemblies (MEAs). PBI MEAs can operate reliably without complex water humidification hardware and are able to run at elevated temperatures of 120-180 OC due to the physical and chemical robustness of PBI membranes. These higher temperatures improve the electrode kinetics and conductivity of the MEAs, simplify the water and thermal management of the systems, and significantly increase their tolerance to fuel impurities. Membranes cast by a newly developed polyphosphoric acid (PPA) Process possessed excellent mechanical properties, higher phosphoric acid (PA)/PBI ratios, and enhanced proton conductivities as compared to previous methods of membrane preparation. p-PBI and m-PBI are the most common polymers in PBI-based fuel cell systems, although AB-PBI and other derivatives have been investigated. The work presented in this dissertation demonstrates the chemical flexibility of PBI polymers which enables the tailoring of specific membrane properties enhancing performance in new and different electrochemical devices with diverse operating conditions.

Included in

Chemistry Commons

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