Battery Materials Analysis Group

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Practical rechargeable batteries are densely packed with various materials that undergo complex physical and chemical processes during charging and discharging.
These processes include the electrochemical reactions of active materials, changes in crystal structure, plastic deformation, stress concentration, and crack formation.
Our research focuses on developing various in situ/operando techniques to observe the complex physicochemical phenomena underlying battery characteristics and clarify their quantitative impact on macroscopic battery performance.
Our goal is to establish the fundamental principles necessary for designing high-performance, long-lasting battery materials.

X-ray photoelectron spectroscopy apparatus (AXIS NOVA, SHIMADZU Kratos)
Raimu Endo, et al., J. Phys. Commun., 5 (2021) 015001
Raimu Endo, et al., J. Phys. Chem. Lett., 11 (2020) 6649-6654
Raimu Endo, et al., J. Phys. Chem. Letters. 13 [31] (2022) 7363-7370

Atomic Force Microscopy (Cypher ES, Asylum Research, Oxford Instruments)
Hiroki Sakai, et al., J. Power Sources., 413 (2019) 29-33.
Ridwan P. Putra, et al., J. Phys. Chem. Lett., 15 (2024) 490–498.

Using a bimodal mode atomic force microscope (AFM) system, we performed nanomechanical mapping of amorphous Si thin film electrodes during the lithium insertion and extraction process. We successfully observed the Young's modulus distribution and surface morphology of the Si electrode in real time, depending on the amount of lithium (x) in lithium silicide (LiₓSi). During the initial stage of lithium insertion, the Young's modulus decreased sharply due to the transformation from Si to LiₓSi, and then decreased gradually until x = 3.46 (capacity 3300 mAh/g), enabling us to establish a correlation between the lithium content (x) and the Young's modulus. Applications to various battery materials are on-going.

Ridwan P. Putra, et al., J. Phys. Chem. Lett., 15 (2024) 490–498.

• Solid-State Battery Group
• Battery Interface Control Group
• Battery Materials Analysis Group
• Photovoltaic Materials Group
• Rechargeable Battery Materials Group
• Solid State Battery Ionics Group
• Environment-Controlled Microscopy Group
• Automated Electrochemical Experiments Team
• Functional Electrolyte Synthesis Team