Stability and electrical conductivity of Nb- or Ta- doped SrTiO₃ perovskites for interconnectors in solid oxide fuel cells

• MORIGA Toshihiro

  Department of Chemical Science and Technology, Graduate School of Advanced Technology and Science, Tokushima University Department of Chemical Science and Technology, Faculty of Engineering, Tokushima University

• MINAKATA Ryota

  Department of Chemical Science and Technology, Graduate School of Advanced Technology and Science, Tokushima University

• NOMURA Yutaro

  Department of Chemical Science and Technology, Graduate School of Advanced Technology and Science, Tokushima University

• ISHIKAWA Hiroki

  Department of Chemical Science and Technology, Faculty of Engineering, Tokushima University

• MURAI Kei-ichiro

  Department of Chemical Science and Technology, Graduate School of Advanced Technology and Science, Tokushima University Department of Chemical Science and Technology, Faculty of Engineering, Tokushima University

• MORI Masashi

  Materials Science Research Laboratory, Central Research Institute of Electric Power, Industry

Abstract

Nb-substituted or Ta-substituted strontium titanates were synthesized by conventional solid-state reactions. For perovskite-type titanates, Sr_1−yTi_1−xM_xO₃, the lattice constant a was found to increase with the amount of dopant (x) added, to maximum values of 3.927 and 3.930 Å for M = Nb and Ta respectively, regardless of Sr deficiency (y). X-ray diffraction studies revealed that the Ta-substituted strontium titanate possesses a wider stable region in its perovskite-type structure against the amount of added dopant (x) and strontium deficiency (y), compared with the Nb-substituted structure. Even in the single phase regions of SrTi_1−xM_xO₃ (M = Nb and Ta) perovskites, scanning electron microscopy images confirmed that after firing at 1500°C for 10 h some SrTi_0.9Ta_0.1O₃ grains showed strontium and tantalum enrichment and titanium dilution, whereas no inhomogeneity was found in SrTi_0.9Nb_0.1O₃. This cationic compositional fluctuation is consistent with the lower electrical conductivity of SrTi_0.9Ta_0.1O₃ compared with SrTi_0.9Nb_0.1O₃ at low temperatures.

Journal

• Journal of the Ceramic Society of Japan

  Journal of the Ceramic Society of Japan 125 (4), 223-226, 2017

  The Ceramic Society of Japan

Keywords

• Perovskite
• Solid oxide fuel cell
• Phase stability
• A-site deficiency

Details

• CRID: 1390282680262078464
• NII Article ID: 130005530324
• DOI: 10.2109/jcersj2.16251
• ISSN: 13486535
• ISSN: 18820743
• Web Site: https://www.jstage.jst.go.jp/article/jcersj2/125/4/125_16251/_pdf
• Text Lang: en
• Data Source:
  • JaLC
  • Crossref
  • CiNii Articles
  • KAKEN
• Abstract License Flag: Disallowed