Development of reactive force-field and molecular dynamics simulation of electrode-electrolyte interfaces

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K04650
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 26020:Inorganic materials and properties-related
• Research Institution: Nagoya Institute of Technology
• Principal Investigator: Kobayashi Ryo 名古屋工業大学, 工学(系)研究科(研究院), 准教授 (70560126)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 分子動力学 / 電池材料 / 界面化学反応 / 固体イオニクス

Outline of Final Research Achievements

In this study, we developed a variable-charge potential to simulate the chemical reaction at the electrode-solid electrolyte interface, a key issue in the development of all-solid-state lithium-ion batteries. Specifically, we focused on two materials, Li-La-Zr-O (LLZO) and LiF. The optimization of potential parameters was performed using training data that included atomic charges, radial distribution functions, and formation enthalpies for various compositions and structures. We then verified the potential accuracy on interface structures not included in the training data. For both Li/LLZO and Li/LiF, the reproducibility of slight atomic displacements at the interface and the interface formation energy was insufficient. Although adopting machine learning potentials showed good reproducibility for defect structures in ternary systems, the construction of potentials for the electrode-electrolyte interface remains a challenge for future work.

Free Research Field

計算材料科学

Academic Significance and Societal Importance of the Research Achievements

原子スケールのシミュレーションは実験で観ることのできない空間・時間スケールの現象を調べるための有効なツールであるが，原子の電荷移動を伴う化学反応のような現象の大規模なシミュレーションは困難である．そのため，電荷移動を再現する原子間ポテンシャルの開発は，今後の全固体電池研究において必須であり，任意の材料の反応ポテンシャル構築が可能となれば，その応用の範囲は広く産業応用の観点でも重要である．反応ポテンシャルの精度改善の可能性とその難易度，適用限界を明らかにすることで，軽量・高速な古典ポテンシャルと低速な機械学習ポテンシャルの選択の有益な判断基準が得られ，効率的な界面シミュレーションに寄与する．