Investigation of degradation reactions at the interface between cathode and anode thin films

2023 Fiscal Year Final Research Report

• Project/Area Number: 22K14470
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 26020:Inorganic materials and properties-related
• Research Institution: Tokyo Institute of Technology
• Principal Investigator: Yasuhara Sou 東京工業大学, 物質理工学院, 助教 (20880032)
• Project Period (FY): 2022-04-01 – 2024-03-31
• Keywords: リチウムイオン二次電池 / 全固体電池 / エピタキシャル薄膜 / 接合界面

Outline of Final Research Achievements

In this study, a decomposition product at the interface between cathode and anode layers was evaluated by preparing an alternatively stacking thin films composed of two kinds of electrode materials which can epitaxially grow on the same substrate. We prepared LiCoO2/Nb2O5 thin films deposited on SrTiO3 substrate and evaluated the crystal structure. The decomposition product in LiCoO2/Nb2O5 epitaxial thin films was estimated as LiNbO3. In addition, we focused on α-LiAlO2 as an interfacial protective layer. We tried to grow an epitaxial thin film of α-LiAlO2 by using a melted target.

Free Research Field

無機機能性材料

Academic Significance and Societal Importance of the Research Achievements

本研究では、LiCoO2とNb2O5の交互積層膜を作製し、接合界面における分解生成物の評価を行った。単結晶薄膜の交互積層膜を作製することで、界面極近傍のみに生成する分解生成物についてX線回折にて評価可能とした。単結晶薄膜の交互積層により、接合界面での分解生成物の可視化を可能にするアプローチは広く応用可能であり、特に接合界面の安定性が重要となる固体電解質開発の分野に有用であることが示唆される。また、全固体電池開発に向け、界面保護層材料としてのα-LiAlO2の検討も行い、エピタキシャル薄膜作製手法を確立した。