2019 Fiscal Year Research-status Report
State of Art Electrolyte materials for Novel Room Temperature All Solid State Fluoride ion Batteries
Project/Area Number |
19K15306
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Research Institution | Tohoku University |
Principal Investigator |
DORAI ARUNKUMAR 東北大学, 多元物質科学研究所, 助教 (10814874)
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Project Period (FY) |
2019-04-01 – 2023-03-31
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Keywords | All Solid State Battery / Fluoride shuttle / Ionic Conductors |
Outline of Annual Research Achievements |
Various fluoride ion conducting solid electrolytes in the fluorite and tysonite structure is prepared by mechanical milling method. The fluorite structured compounds are found to exhibit high ionic conductivity at ambient temperatures. Phase purity has been confirmed by XRD and DSC. The ion dynamics in PbSnF4 and RbSn2F5 is probed using temperature dependent 19F PFG-NMR, T1 relaxation and Impedance Spectroscopy. The diffusion coefficient calculated from ionic conductivity (ac impedance) and correlation time (19F T1 relaxation) using the Nernst-Einstein and Einstein-Smoluchowski relations correlates well which confirms that fluoride ions are the predominant conductors. The relaxation time is very short at ambient temperatures restricting the diffusion measurement to high temperatures only.
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Current Status of Research Progress |
Current Status of Research Progress
1: Research has progressed more than it was originally planned.
Reason
We have purchased a planetary ball milling equipment using this fund which enabled us to synthesize the compounds as per our plan. The characterization of the materials has been carried out without any trouble since we used the common equipment facility of our institute that was readily available to use. Moreover the main focus of the work is to study the ion dynamics using NMR. The prepared materials needed to be characterized over a wide range of temperature. The availability of the high temperature NMR equipment in our institute supported the research to be done without any lag.
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Strategy for Future Research Activity |
We prepared various fluoride ion conducting materials and measured the ionic conductivity by ac impedance technique. The temperature dependent 19F NMR measurements has been used to study the ion dynamics. However the diffusion coefficient measurement has been restricted to high temperatures due to the very short T1 relaxation time of these materials. One among the reason for the very short relaxation time observed is may be due to impurities in the compound. Hence, the measurement of diffusion coefficient for powder samples is a challenging process. Therefore it has been planned to prepare phase pure compounds using different preparation technique and study the dynamics. In addition, other fluoride ion conducting solid electrolytes will be prepared and they ion dynamics will be studied.
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Causes of Carryover |
The high temperature NMR measurements requires about a day for a single measurement. Since we have to characterize the samples in a wide temperature range, the remaining amount from the previous fiscal year will be used to meet the increase in usage in the following fiscal year.
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Research Products
(1 results)