Project No: FE0009682
Performer: University of Connecticut
Shailesh Vora Technology Manager National Energy Technology Laboratory 626 Cochrans Mill Road P.O. Box 10940, MS 922-204 Pittsburgh, PA 15236-0940 (412) 386-7515 firstname.lastname@example.org Joseph Stoffa Project Manager National Energy Technology Laboratory 3610 Collins Ferry Road P.O. Box 880, MS PO3B Morgantown, WV 26507-0880 (304) 285-0285 email@example.com Prabhakar Singh Principal Investigator University of Connecticut 44 Weaver Road, Unit 5233 Storrs, CT 06269-5233 (860) 486-8379 firstname.lastname@example.org
DOE Share: $499,372.00
Performer Share: $124,843.00
Total Award Value: $624,215.00
Performer website: University of Connecticut - http://www.engr.uconn.edu
The University of Connecticut (UConn) team will perform an evaluation and analysis—using experimentation and computational simulation—of degradation phenomena in lanthanum manganite- and cobaltite-based cathode electrodes when exposed to air atmosphere conditions during solid oxide fuel cell (SOFC) operation. The project will examine the role of dopants, electric polarization, gas phase contaminants, oxygen stoichiometry (proportions), and A:B ratio on the long-term bulk and interfacial stability of lanthanum manganite and cobaltite cathodes. Cathode materials will be characterized to develop both initiation and propagation processes responsible for chemical and morphological changes. The role of electrode poisoning in the presence of chromium vapor will be examined using existing test facilities capable of generating a wide range of vapor pressures in humidified air.
Program Background and Project Benefits
This project focuses on developing an understanding of the electrical, chemical, and physical processes responsible for cathode degradation under real world air atmosphere exposure conditions. Improved cell/stack life and performance will reduce operating cost and increase efficiency, resulting in reduction in the cost of electricity and reduction of CO2 emissions from the entire platform. Specifically, this project will study the role of electrode polarization and exposure conditions on cell performance degradation, examine the role of electrode poisoning in the presence of Cr vapor, and use computational tools to theoretically deduce cathode degradation mechanisms due to air contaminants.
Project Scope and Technology Readiness Level
This project is focused on evaluation and analysis of degradation phenomena in lanthanum manganite-based cathode electrodes when exposed to 'real-world' air atmosphere conditions during SOFC systems operation by both experimentation and computational simulation. In particular, the interest is in product formation and interactions with air contaminants, dopant segregation and oxide exolution at free surfaces, cation interdiffusion and reaction products formation at the buried interfaces, interface morphology changes, lattice transformation and the development of interfacial porosity and micro-cracking and delamination from the stack repeat units. The feasibility of the mitigation approaches will also be tested in accelerated conditions enabling rapid evaluation of the cation transport and gas-solid phase interactions. Sensitive probes to measure chemical composition and phase content, in concert with high-accuracy measurements of lattice constants, will provide the first evidence of the cation diffusion-controlled reactions. Structural and morphological characterization of cathode samples will be performed using existing laboratory capabilities such as electrical impedance spectroscopy, high temperature controlled atmosphere X-ray diffractometry, hot stage field emission scanning electron microscopy, focused ion beam microscopy and micro-machining, transmission electron microscopy, Auger electron spectroscopy, and X-ray photoelectron spectroscopy (XPS) techniques. The results will be used to identify and develop initiation and progression of the interfacial and surface reactions. Thermochemical simulation of interface atomic configurations using first principle thermodynamics, density functional theory and statistical mechanics will be utilized. Generalized gradient approximation (GGA) with projector augmented wave (PAW) method as implemented in Vienna Ab initio Simulation Package (VASP) along with a small number of beyond- density functional theory DFT computations will be performed.
The Technology Readiness Level (TRL) assessment identifies the current state of readiness of the key technologies being developed under the DOE’s Clean Coal Research Program. In FY 12, this project was not assessed. The TRL assessment process and its results including definition and description of the levels may be found in the "2012 Technology Readiness Assessment-Analysis of Active Research Portfolio".