Study on degradation and charging mechanism to develop lithium-ion secondary batteries
| Project/Area Number |
15K04603
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Research Field |
Nanostructural physics
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| Research Institution | Kansai University |
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Principal Investigator |
Takata Keiji 関西大学, システム理工学部, 教授 (50416939)
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| Co-Investigator(Kenkyū-buntansha) |
内野 喜一郎 九州大学, 総合理工学研究院, 教授 (10160285)
梶山 博司 徳島文理大学, 理工学部, 教授 (80422434)
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| Project Period (FY) |
2015-04-01 – 2019-03-31
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| Project Status |
Completed (Fiscal Year 2018)
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| Budget Amount *help |
¥4,940,000 (Direct Cost: ¥3,800,000、Indirect Cost: ¥1,140,000)
Fiscal Year 2017: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
Fiscal Year 2016: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
Fiscal Year 2015: ¥2,210,000 (Direct Cost: ¥1,700,000、Indirect Cost: ¥510,000)
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| Keywords | ひずみイメージング / リチウムイオン二次電池 / プローブ顕微鏡 / リチウムイオン2次電池 |
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| Outline of Final Research Achievements |
Non-destructive observation of the migration of Li ions with high spatial resolution is important. Charging and discharging cause changes in volume of electrode materials. Scanning probe microscopy can allow high resolution imaging of these volume changes, which enables us to investigate Li-ion migration without destruction.
Volume changes of LiCoO2 generated by Li insertion/extraction are very small, 10-2, and so they hardly appeared in our obtained images. However, the LiCoO2 particles were imaged as dark portions with no signal, because changes in volume in the interspace were detected. We concluded that electrolyte flux induced by the gradient of Li-ion concentration in the cathode, which was generated by charging/discharging, caused the volume changes in the interspace. Furthermore, we observed dry-out of electrolyte. The electrolyte flux and dry-out are the most important issues for increasing the energy density of batteries.
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| Academic Significance and Societal Importance of the Research Achievements |
リチウムイオン電池のエネルギー密度向上のためには、活物質層を厚くする必要がある。しかし厚い活物質層への電解液の浸透は難しい。さらに、充放電に伴うリチウムイオン移動を円滑に行うためには、活物質層中の電解液の流動が必要である。これらのため、活物質層の厚みは制限されている。従って電解液の浸透と流動のための活物質粒子の分散は重要な技術課題である。
本研究成果は、電解液の活物質層中への浸透と流動を非破壊高分解能計測できる手法を提供するとともに、電解液のドライアウトを捉えられることを実証した。粒子分散の結果を検証し、その検証結果を参考に、さらなる技術改良を行うために不可欠な評価方法を提供したと考えられる。
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Report
(5 results)
Research Products
(27 results)
