| Co-Investigator(Kenkyū-buntansha) |
ITO Masami Oita University, Research and Development Center, Associate Professor, 地域共同研究センター, 助教授 (60274742)
INOUE Takanori Oita University, Faculty of Engineering, Associate Professor, 工学部, 助教授 (40243969)
ISHIHARA Tatsumi Kyushu University, Faculty of Engineering, Professor, 大学院工学研究院, 教授 (80184555)
NISHIGUCHI Hiroyasu Oita University, Faculty of Engineering, Research Associate, 工学部, 助手 (10274739)
|
|---|
| Research Abstract |
In this study, new fast oxide ion conducting oxide was investigated and it was found that mixed oxide of La_2GeO_5, LaOF, and Fe heavily doped LaGaO_3 based oxide exhibits extremely fast oxide ion conductivity comparing with the conventional materials. Furthermore, conduction mechanisms in LaGaO_3 based oxide was studied in details and it was found that oxide ion conductivity in LaGaO_3 based oxide was improved by doping Fe, Co, and Ni. Partial electronic conduction was also observed. However, if the amount of doped Co, Ni, or Fe is small, the contribution of electronic charge carrier is not significant. In particular, it was found that the oxide ion conductivity in LaGaO_3 based oxide greatly improved by doping Fe. In agreement with the improved oxide ion conductivity, power density of the solid oxide fuel cells is also improved by using Fe, Co, or Ni doped LaGaO_3 for electrolyte. On the other hand, crystal structural analysis of La_2GeO_5 based oxide suggests the large anisotropic oxide ion conductivity is occurred in this oxide. The high oxide ion conductivity in this La_2GeO_5 system seems to result from the high mobility of oxide ion. Making thin film of La_2GeO_5 based oxide with nanometer level thickness was successfully prepared by Laser Abrasion Methods. It was found that the unusual increase in oxide ion conductivity is achieved as the thickness of the La_2GeO_5 based oxide film decreased to a nanometer size. Furthermore, accumulation of La_2GeO_5 nanometer sized film on LaGaO_3 based oxide film with nanometer size thickness is effective for increasing the oxide ion conductivity.
|
