2019 Fiscal Year Research-status Report
Study of the oxygen-ion mobility in complex metal-oxide materials prepared by topochemical methods
| Project/Area Number |
19K23650
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| Research Institution | Kyoto University |
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Principal Investigator |
AmanoPatino Midori (Estefani) 京都大学, 化学研究所, 特定助教 (80849018)
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| Project Period (FY) |
2019-08-30 – 2021-03-31
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| Keywords | Topochemical synthesis / Perovskite materials / Oxygen deficiency / Structure analysis |
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| Outline of Annual Research Achievements |
This project explores metal-oxide materials synthesized by topochemical methods as potential oxygen-ion conducting materials for applications that require moderate temperatures. The focus is on investigating the influence of structural aspects at the chemical level (for example, cation or vacancy orderings), on the oxide-ion mobility.
A series of perovskite and perovskite-related materials were prepared by using a combination of reductive/oxidative atmospheres coupled with heating and pressure treatments. Each material exhibits different types of cation and/or vacancy orderings. Selected phases include the B-site ordered material LaSrNiRuO4 and the A-site mixed materials La1-xBaxMnO3-δ (x = 0.25, 0.50).
For detailed structural characterization of the materials, synchrotron X-ray diffraction (SXRD) data were collected at the central facilities NSRRC, Taiwan and SPring-8, Japan. Reductive and/or oxidative thermogravimetric analysis (TGA) measurements were also carried out for complementary analysis with the SXRD data.
From the variable temperature SXRD data from both the LaSrNiRuO4 and La1-xBaxMnO3-δ (x = 0.25, 0.50) phases, insights about the intake of oxide-ions in the structures have already been extracted and are being further analyzed. In particular, the study of the oxide-ion incorporation behaviour of LaSrNiRuO4 materials raises awareness towards the microstructural features during topochemical processes. Our results reveal that the accessibility of topochemical products needs to consider the microstructural characteristics of the starting materials.
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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 been able to prepare some novel materials by topochemical methods and collected high quality data from them by using X-ray diffraction techniques (including synchrotron X-ray diffraction at central facilities such as SPring-8, Japan and the NSRRC, Taiwan) by the hand with thermogravimetric analysis (which tracks the change in mass associated with intake of oxygen). The results are being valuable in the refinement of the synthesis methods for the preparation of additional materials, as well as for understanding the influence of structural aspects on the incorporation of oxide-ions in perovskite related structures such as that of the B-site ordered LaSrNiRuO4 material and the A-site mixed materials La1-xBaxMnO3-δ (x = 0.25, 0.50) with different distributions of oxide-ion vacancies.
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| Strategy for Future Research Activity |
Having carried out the basic structural characterization of the materials thus far prepared, this FY2020 the focus will be twofold: on the one hand, synthesis of new materials will be implemented and on the other hand, further studies of relevant details in the relationship between structure and properties will be performed.
The steps forward involve further analysis of the high quality data collected for the so far prepared materials, as well as transport property measurements. The latter include impedance spectroscopy and conductivity measurements with the goal of understanding the details about the oxide-ion mobility and oxide-ion conduction properties.
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| Causes of Carryover |
Although I had planned to ask for technical assistance for experiments, it was difficult to find an appropriate candidate for the specific experiments. I thus did not use the budget assigned for such assistance during FY2019. I will use the transferred budget to FY2020 for experimental consumables (encompassing both the furthering of synthesis techniques and specialized characterization techniques), as well as for publication and dissemination of results.
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