Effects of Al3+, Fe3+ and Ga3+ dopants on the germanate-based apatites as electrolyte for use in solid oxide fuel cells

• Main Authors: Pei-Hsun Li, 李沛勳
• Other Authors: 王錫福
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/y576ee

碩士 === 國立臺北科技大學 === 材料科學與工程研究所 === 102 === The purpose of this study was to develop apatite-type lanthanum germanate-based solid electrolytes for SOFC (Solid Oxide Fuel Cell). In order to achieve the best conductivity of the electrolyte materials applications, these ceramics were doped with various ions radii that was different from Ge4+ ion and to substitute part of the ion Ge4+ in La9.5Ge6O25.25. Various dopants including Al2O3、Fe2O3 and Ga2O3 were added into to apatite-type lanthanum germanate-based solid electrolytes, respectively. These lanthanum germanate-based solid electrolyte powders were synthesized by solid state reaction. These specimens were sintered at various temperatures and periods of time, then the conductivity of the specimens were measured. The results showed that, the secondary phase of LaFeO3 is formed by doping FeO2, the electrical conductivity is reduced significantly by doping Al2O3. Therefore, the two kinds of dopant were unfavorable used in the lanthanum germanate-based electrolytes. The La9.5Ge5.7Ga0.3O26.1 possesses the best conductivity (0.031 S/cm) at 800oC.