Electrical Properties of Oxygen Vacancy Conducting Solid Electrolyte Ceramics in the Microwave Region

摘要

The compounds with fast oxygen vacancy transport are attractive materials for SOFC. The powder of Ce_(0.8)Gd_(0.1)O_(1.9), Ce_(0.9)Gd_(0.1)O_(1.95), Ce_(0.8)Sm_(0.2)O_(1.9), Ce_(0.85)Sm_(0.15)O_(1.925), 8YSZ, and 10ScSZ compounds with different BET from company Fuel Cell Materials were used for the sintering of the ceramics. The sintering of the ceramics samples was conducted in air at temperature T = 1773 K. The SEM images of the surfaces of the ceramics have shown that grain sizes increase with decrease of BET of the powder used for sintering of the ceramics. The complex impedance, electric conductivity, dielectric permittivity, and dielectric losses tanδ in frequency range 10~6-1.2·10~9 Hz and temperature range from room to 700 K were carried out. A relaxation dispersion of the electric parameters was found for all compounds. The dispersion is caused by the V_O~(··) transport in grains of the ceramic samples. The values of the bulk conductivity, its activation energy, characteristic relaxation frequency, dielectric permittivity, and density of the samples are dependent on BET of the powder used for sintering of the ceramics.