2016 Fiscal Year Research-status Report
Improvement of fuel cell electrolytes by strain engineering
| Project/Area Number |
16K18235
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| Research Institution | Kyushu University |
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Principal Investigator |
ハリントン ジョージ 九州大学, 次世代燃料電池産学連携研究センター, 助教 (20753718)
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| Project Period (FY) |
2016-04-01 – 2018-03-31
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| Keywords | Electrolytes / Solid oxide fuel cells / Thin films / Doped ceria / Lattice strain / Oxygen ion transport / Interfaces / Pulsed laser deposition |
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| Outline of Annual Research Achievements |
Preliminary samples have been fabricated, structurally characterised, and the transport properties assessed. Although the results were promising, the presence of grain boundaries limits the impact of the findings.
A new set of samples grow on a different substrate, have eliminated the problems associated with grain boundaries, and have demonstrated a modification of the transport properties with lattice strain.
An oxygen exchange rig is currently under construction. This will allow the assessment of oxygen diffusivity in films grown on conductive substrates, which was not previously possible by conventional electrical testing.
Oral presentations have been given on this work at the European MRS conference in Lille and the Electroceramics XV conference in Limoges during FY2016.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
We have made excellent progress fabricating high quality doped ceria films with a controllable degree of lattice strain. Despite an initial setback, where a much higher density of grain boundaries than expected was present in the films, we found that by switching to a different substrate we were able to mitigate these issues. In addition, we have identified that varying the temperature of thermal treatments is a reliable way to alter the strain in our films.
Currently we are finishing the structural characterisation of the new thin film system by x-ray diffraction, and will start the transport measurements in the near future, however, preliminary measurements show a promising link between lattice strain and conductivity.
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| Strategy for Future Research Activity |
The final structural characterisation of the new film system by x-ray diffraction is almost complete, and will then be supported by raman and transmission electron microscopy measurements. Next the transport of the films will be assessed electrically by impedance spectroscopy and also using the oxygen exchange rig, which is currently under construction. This will allow the link between lattice strain and defect association to be evaluated.
In addition, the surface segregation of the dopant in rare earth doped ceria films will also be investigated by low energy ion scattering to elucidate the effect of dopant size and lattice strain on the rate and extent of dopant segregation.
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| Causes of Carryover |
Due to delays in the sample fabrication, the construction of the exchange rig was delayed. Some of the parts required could not be delivered in time within FY2016. Therefore, these parts will be ordered and the exchange rig constructed in FY2017.
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| Expenditure Plan for Carryover Budget |
The remaining budget will be spent on ordering the parts for the exchange rig, the hiring of a researcher for 2 months to assist in the characterisation of the samples, fees for equipment booking such as the transmission electron microscope and low energy ion scattering, and travel to conferences to disseminate the research.
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