Preparation and characterization of solid electrolytes for solid oxide fuel cells. Quarterly report, July 1--September 30, 1996 [report]

1996 unpublished
During this quarter, we have analyzed EXAFS spectra of rare earth doped ceria and identified Gd and Sm doped ceria electrolytes for further investigations in this project. Although electrical properties of the material have been examined in detail , very littile work has considered the microstructurallproperty relationships, particularly in relationship to atomic and geometric structures of these ceria based oxides. Earlier we have observed an ionic conductivity of 8.3 X S/Cm in the ( CeOz
more » ... Gd01.5)0.2 at 800 C . which is approximately four times that of Y203 doped ZrO3 doped Z r O z at the same temperature. The fraction of Ce4 ions reduced to Ce+3 as a function of temperature and oxygen partial pressure. The partial reduction of cerium oxide generates mobile electrons and causes electronic conductivity in the electrolyte at temperatures above 500 C In this quarter, we have attempted to measure the microstructural properties using SEM, E M and HVC STM techniques. The PI has generated to funds to acquire HVC STM from National Science Foundation. He has involved in the purchasing procedures since this instrument is expensive and require custom made design etc. Dr. R.Bobba has issued the design and requirements to the university purchasing department in order to solicit bids from commercial vendors. In the previous quarter, one of the graduate student and the research associate have initiated the study of the performance of commercial Nation 1 17, 11 5, and 112 and compared with platinum and platinum ruthenium. The graduate students and other staff in the project spent time to familiarize with the operation of the fuel test station. This included understanding the effect of back pressure, gas flow rate, and humidifier temperature. The current output was found to be satisfactory and is same for the similar membranes. Inadvertent heating of the fuel cell to 146 C R
doi:10.2172/584870 fatcat:um35ejowkrbvvegnm2houkczxu