ABSTRACTTitle of thesis: PATTERNED NICKEL ANODE STABILITY IN SOFC ENVIRONMENTS WITH H2, COAND CH4 FUEL FEEDSBenjamin Paul Becker, Master of Science, 2005Directed By: Professor Gregory S. Jackson, Department of Mechanical Engineering Single cell solid oxide fuel cells supported on single crystal YSZ electrolytes with patterned Ni anode s fabricated through sputter deposition and photolithographictechniques and with porous LSM/YSZ cermet cathodes were tested electrochemicallyto assess the stability of the Ni anodes in SOFC environments. Anode stability and electrochemical performance for H2, CO and CH4electrochemical oxidation were characterized at cell temperatures between 750 ºC and 800 ºC under humidified (PH20/Pfuel = 0.05) conditions. Changes in performance of anodes polarized by typical working fuel cell overpotentials (100 - 200 mV) were compared to anodes kept at open circuit conditions. An increase in surface roughness was much greater for the polarized anodes than those kept under open circuit conditions. Electrochemical impedance spectroscopy and sweep voltammetry, over 10 continuous hours of testing,consistently showed constant performance for the polarized anodes and a drop in performance for the open circuit anodes.PATTERNED NICKEL ANODE STABILITY IN SOFC ENVIRONMENTS WITH H2, CO AND CH4 FUEL FEEDSByBenjamin Paul BeckerThesis submitted to the Faculty of the Graduate School of the University of Maryland, College Park, in partial fulfillmentof the requirements for the degree ofMaster of Science in Mechanical Engineering2005Advisory Committee:Assistant Professor Bao Yang, Chair Associate Professor Gregory S. JacksonProfessor Michael R. Zachariah© Copyright byBenjamin Paul Becker2005iiAcknowledgementsI would like to thank my advisor Prof. Gregory S. Jackson for his support and guidance throughout the production of this thesis and my time as a graduate student. He dedicated time and effort, much more than expected to listen to my difficulties and help me learn and succeed. His flexibility, friendliness and encouragement made completing my work at the University of Maryland very pleasant and rewarding. I also would like to thank my colleagues at The Center for Fuel Cell Research Dr.Mary Sukeshini and Bahman Habibzadeh for their contributions to this work. Dr. Sukeshini was always willing to explain the physics associated with fuel cells and help interpret electrochemical data. Bahman Habibzadeh shared the work of constructing and running experiments and helped me through many of the difficulties of graduate studies.Thanks go to my colleagues at the Biochemistry Department: Oktay Demerican, Mike Pomfret , Prof. Bryan Eichhorn and Prof. Rob Walker. Oktay Demerican provided the materials and procedure necessary for cathode fabrication and assisted in analysis of XRD data. Mike Pomfret operated the Raman spectrometer on post-experimental patterned anodes and helped interpret the results. And a special thanks to all my colleagues for being friendly co-workers who made the workplace enjoyable.Other people who helped make this thesis possible include: Tom Loughran who deposited many Ni coatings and who shared his expertise in photolithographiciiitechniques, John Barry, Nolan Ballew and Jon Hummel for their help in sputtering Ni coatings and finally Tim Maugel for operating the SEM and EDAX instrument.Thanks also to Prof. Michael R. Zachariah and Prof. Bao Yang for being a part of my defense committee.And finally I would like to thank my family for their support throughout my time as a graduate student and for providing an environment of encouragement that gave me the ability to take on graduate level study.ivTable of ContentsAcknowledgements....................................................................................................... iiTable of Contents......................................................................................................... ivList of Tables ................................................................................................................ vList of Figures.............................................................................................................. viChapter 1: General Introduction ................................................................................... 11.1 Introduction to Fuel Cells ................................................................................... 11.2 The Solid Oxide Fuel Cell .................................................................................. 61.2.1 SOFC Materials ......................................................................................... 111.2.2 SOFC Performance .................................................................................... 151.3 Patterned Anodes for Understanding act and SOFC Kinetics.......................... 201.4 Objectives of the Current Study........................................................................ 22Chapter 2: Experimental ............................................................................................. 242.1 MEA Fabrication .............................................................................................. 242.1.1 Cathode Fabrication................................................................................... 252.1.2 Anode Microfabrication............................................................................. 262.2 Experimental Setup........................................................................................... 352.2.1 MEA Wiring .............................................................................................. 352.2.2 Experimental Rig ....................................................................................... 402.2.3 Temperature and Flow Control.................................................................. 442.3 Electrochemical Measurements ........................................................................ 452.4 Range of Conditions Studied ............................................................................ 49Chapter 3: Non-electrochemical Test Results............................................................ 55Chapter 4: H2 Oxidation............................................................................................. 66Chapter 5: CO Oxidation ........................................................................................... 77Chapter 6: CH4