Fuel cells have steadily gained prominence as power systems for motive and stationary applications due to high energy conversion efficiencies and absence of carbon dioxide emissions at their point of use. Large scale technology deployment requires additional cost reduction and durability improvement. Cell degradation is dependent on design and operating conditions, which impact transient response. Thus, control strategies for future state-ot-the-art fuel cell systems will require adaptations.

It will be shown that extending durability requires a clear understanding of degradation mechanisms to facilitate the development of effective solutions. In turn, advanced diagnostic methods are needed to obtain experimental data to derive mechanisms. This strategy will be demonstrated using contamination as a representative contribution to cell degradation. Contaminants in oxidant (air) and fuel (hydrogen) reactant streams, typically at or below the ppm level, disrupt cell operation by adsorbing on catalyst surfaces or by affecting ion transport in the electrolyte. Results obtained with a recently developed method to measure and separate oxygen mass transfer coefficients into fundamental contributions confirmed the link existing between cell voltage losses due to kinetic (oxygen reduction) and oxygen mass transfer effects. Oxygen rather than air would not only minimize contamination concerns but would also reduce cost (higher power density system), improve response time, and require control modifications (removal of the air compressor or blower).

Biography

Jean St-Pierre, PhD, PEng is a graduate of Polytechnique, Montréal, Canada and holds 3 engineering degrees from this institution (PhD, MScA, BIng). More than twenty-five years of his industrial and academic career has been devoted to the development of proton exchange membrane fuel cells including aspects such as water management, freezing, degradation mechanisms, mathematical modeling, diagnosis and measurement methods, electrocatalysis, pure oxygen operation for space and air independent applications, and reactant stream unit operations (gas separation and fuel reforming catalysts). He previously held principal research scientist and research professor positions at respectively Ballard Power Systems (1995-2005), an acknowledged fuel cell manufacturing leader, and the University of South Carolina (2006-2010), formerly the site of the sole National Science Foundation industry/university collaborative research center for fuel cells. He is currently a researcher at the University of Hawaii – Manoa and focuses on fuel cell and related technology activities. His work has led to more than 115 journal papers, book chapters, and conference proceedings, and to more than 30 granted, published, and provisional patents. He is an advisory board member of Sci and editorial board member of Electrochem and Molecules. He is a member of the Electrochemical Society, the International Society of Electrochemistry, the American Association for the Advancement of Science, and Sigma Xi.