2020 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 |
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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 / Solid Electrolyte |
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| Outline of Annual Research Achievements |
The ion transport properties of Tysonite structured (LaF3) fluoride ion conducting solid electrolytes prepared by mechanical milling technique is investigated using 19F NMR and ac impedance spectroscopy. Aliovalent doping (Pb,Sn,Ba) of the fluorite structured LaF3 has resulted in the increase in ionic conductivity of about 1 order, which is due to the increase in the unit cell volume as confirmed by XRD. The fluoride ion dynamics in aliovalent doped LaF3 is probed probed in a wide range of temperature ranging from RT~773K by using 19F NMR spectra, T1 relaxation time and Impedance Spectroscopy. From the temperature dependent NMR and impedance analysis it is confirmed that the ionic conductivity is contributed by the exchange of fluoride ions in the F1 and F2 sites at higher temperatures.
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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
In the present research, our main aim is to identify and develop high conducting solid electrolytes for the development of all solid state fluoride ion batteries. We have prepared various fluoride ion conductors in the tysonite and fluorite structured compounds and studied their ion dynamics and transport properties in a wide range of temperature using 19F NMR spectroscopy. The developed fluorite structured compounds exhibit high conductivity at ambient temperature compared to the tysonite structured compounds. On the other hand aliovalent doping of tysonite structured compounds have increased the ionic conductivity. Our efforts to measure the diffusion coefficient directly has been hindered by the very short relaxation time of the developed compounds. Further studies are in progress.
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| Strategy for Future Research Activity |
In the development of all solid state batteries identifying a suitable solid electrolyte with good transport properties and compatibility towards the electrodes is necessary. Moreover, the cathode and anode material selection plays a vital role in the potential and performance of the battery. The ion transport properties will be evaluated in a wide range of temperature using NMR spectroscopy and the developed solid electrolytes will be tested with different combinations of cathode & anode materials and their suitability and performance will be evaluated appropriately. In the present work, based on the ion transport properties of the prepared compounds, a model all solid state fluoride ion battery will be constructed and its performance will be evaluated.
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| Causes of Carryover |
In the previous academic year, the travel expenses has not been utilized due to the pandemic situation. 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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