Electrochemical and degradation study of Sr0.6Na0.4SiO3-δ
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The high ionic conductivity of Na-doped SrSiO3 (SNS) is a topic of interest due to contradictory reports on its conductivity and stability by various groups. From a recent NMR study, it is proposed that Na+ is mainly responsible for ionic conductivity in an amorphous Na2Si2O5 phase present in SNS. The present study further extends to determine experimentally the ion transport number as well as material characteristics after long time annealing at 600 °C. The conductivity behavior of as-sintered and annealed nominally Sr0.6Na0.4SiO3-δ is investigated and a sharp fall (~ 2 order magnitude) of the same at 800 °C is found. An XPS study is included for comprehensive understanding of conductivity and degradation behavior of SNS material. On basis of the collective results, we propose a rational description of the conduction and material degradation of SNS.
KeywordsSrSiO3 Transport number SOFC Ionic conductivity Protonic conductivity
We gratefully acknowledge helpful conversations on XPS analysis with Dr. Ajay K. Shukla, Scientist, National Physical Laboratory, New Delhi, India.
The authors are thankful to the financial support of the EU ERA-NET and DST for New INDIGO Project “Multi-Functional Nanocomposite Materials for Low-temperature Ceramic Fuel Cells (NANOMFC)”, the Science and Engineering Research Board (SERB), DST, New Delhi, wide letter number PDF/2016/002473, and the Research Council of Norway (project no. 237642).
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