SECA Core Technology - Cell Development
EMSL Project ID
47693
Abstract
One of the primary goals of the SECA Core Technology program is the development of cost-effective materials and fabrication techniques for the various components in SOFC stacks and systems. In this proposed work, we have an anode-supported solid oxide fuel cell with a LSCF cathode operated at 750 degrees C for over 1000 hours at constant current approximating an operating voltage of 0.8 V. X-ray diffraction (XRD) of the cathode was performed continuously over the entire test duration to monitor any changes that may occur in the XRD patterns over time during cell operation. The XRD results are compared to those of a duplicate cell that, rather than generating current, was held at open circuit voltage OCV for over 1000 hours in the XRD test stand and to an earlier constant current test that was conducted for slightly over 60 hours at around 0.8 V. Summation of the XRD patterns taken over the entire duration of the tests resulted in cumulative count times that greatly enhanced the signal to noise ratio of peaks associated with minor phases, making it possible to identify LaCoO3, Fe3O4, and Co3O4 in the cathode in quantities of less than 2%. Additionally, gradual lattice strain in LSCF was detected in the ~60 hour test and in Fe3O4 and Co3O4 in the ~1000 hour test that was conducted at OCV. Previous work by other authors has determined that Sr is precipitated from the LSCF lattice during cell operation, but Sr-rich phases could not be resolved by XRD in the present study. This may be due to the fact that any exsolved Sr can react with other elements to form Sr-rich perovskite phases that are isostructural with the LSCF. Therefore, FIB is needed to prepare samples for TEM analysis that will confirm the presence of Fe3O4, Co3O4, and Sr-rich phases in the cell cathode.
Project Details
Start Date
2012-09-27
End Date
2014-09-30
Status
Closed
Released Data Link
Team
Principal Investigator
Co-Investigator(s)
Related Publications
Hardy JS, JW Templeton, DJ Edwards, and JW Stevenson. 2013. "In-Operando XRD of LSCF Cathodes on Anode-Supported SOFCs at Various Temperatures." Presented by John Hardy at the 37th International Conference and Exposition on Advanced Ceramics and Composites, Daytona Beach, Florida on January 30, 2013.