Evaluation of elastic constants of the positive electrode materials for lithium-ion battery

2018 Fiscal Year Final Research Report

• Project/Area Number: 17K17603
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Inorganic materials/Physical properties; Materials/Mechanics of materials
• Research Institution: Tohoku University
• Principal Investigator: Kimura Yuta 東北大学, 多元物質科学研究所, 助教 (60774081)
• Project Period (FY): 2017-04-01 – 2019-03-31
• Keywords: 応力 / Li化学ポテンシャル

Outline of Final Research Achievements

In this study, we experimentally evaluated the change in Li chemical potential of a positive electrode material for lithium-ion battery under mechanical stress by using an electrochemical potential probe. We prepared the electrochemical potential probe using liquid electrolyte and a LiCoO2 thin film which was deposited on the Pt-coated SiO2 substrate. This potential probe was brought into contact with the mechanically-stressed positive electrode material and the electromotive force between the positive electrode material and the potential probe was measured. The observed electromotive force was in good agreement with the values which were theoretically estimated based on thermodynamics. Thus we concluded that the change in Li chemical potential of a positive electrode material under mechanical stress was correctly and qualitatively measured by using our electrochemical potential probe.

Free Research Field

電気化学

Academic Significance and Societal Importance of the Research Achievements

全固体リチウムイオン二次電池では、リチウムイオンの挿入脱離に伴う材料の体積変化などに起因して、電池内に応力が発生することが想定される。材料中に生じた応力は、電気化学的特性や熱力学的特性といった、材料自体の特性を大きく変化させることも知られている。しかしながら、機械的応力が材料特性に及ぼす影響を定量的に評価した研究例も少なかった。本研究では、機械的応力が、特定の材料特性にどの程度影響を及ぼすかを定量的に評価することに成功した。本研究の成果は、応力による物性変化を考慮した全固体Liイオン電池の設計を行う上で重要であると考えられる。