ELECTRICAL PROPERTIES OF Ce-DOPED SrMnO_3 AS A CATHODE MATERIAL

摘要

We found that the partial substitution of Ce for Sr in SrMnO_3 could stabilize the perovskite-type structure down to room temperature. The dependence of electrical conductivities on temperature was measured from 1000℃ to room temperature in air. By doping with Ce, the electrical conductivities of SrMnO_3 were enhanced drastically. Especially, Sr_(0.7)Ce_(0.3)MnO_(3-α) showed higher conductivity (290 S*cm~(-1) at 1000℃) than that of conventional La_(0.8)Sr_(0.2)MnO_3 (about 175 S*cm~(-1)). Sr_(0.7)Ce_(0.3)MnO_(3-α) was chemically compatible with cerium-based electrolyte at fabrication temperature. In the electrochemical gas cell using Sr_(0.9)Ce_(0.1)MnO_(3-α) as a cathode material and Ce-based electrolyte, contact resistance between the cathode and the electrolyte was as low as the case of Pt electrode although the polarization should be minimized by controlling the microstructure and the processing of the cathode.