Clarification of the redox potentials for rechargeable-battery electrode materials by direct observations of valence and conduction bands

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K05414
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 32020:Functional solid state chemistry-related
• Research Institution: National Institute of Advanced Industrial Science and Technology
• Principal Investigator: Asakura Daisuke 国立研究開発法人産業技術総合研究所, エネルギー・環境領域, 主任研究員 (80435619)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: リチウムイオン電池 / 電極材料 / 電子状態 / X線分光 / 酸化還元電位

Outline of Final Research Achievements

The relation between the electronic structure and electrode performance including the working voltage of electrode materials for Li-ion batteries (LIBs) has been investigated by use of synchrotron radiation X-ray spectroscopies. The valence band and conduction band have been element-selectively/orbital-selectively observed using soft X-ray emission spectroscopy and resonant photoemission spectroscopy which had hardly been employed for the electrode materials. The top of valence band and bottom of conduction band determine the redox potential. By investigating those energy levels for various electrode materials, knowledges to develop novel high-voltage cathode materials have been obtained successfully.

Free Research Field

電子物性

Academic Significance and Societal Importance of the Research Achievements

専ら電子物性などの分野で用いられてきた軟X線発光分光や共鳴光電子分光なども駆使して、LIBの電極材料の電子状態を詳しく調べることで、電子論的な観点からの電極性能の解明に成功した。また、固体物理分野と電気化学分野の領域横断的な研究になった点も成果と考えている。社会的意義という点においては、今後の高性能電池の開発に活用できる重要な知見が得られており、応用研究・実用化にも十分に貢献できる内容と言える。