Unveiling Atomic and Electronic Structures in Energy Storage: Metal Chloride and Alkali Metal Intercalation in Bilayer Graphene

Yung-Chang Lin^1,2*, Rika Matsumoto⁶, Qiunan Liu², Silvan Kretschmer³, Mahdi Ghorbani-Asl³, Pablo Solís-Fernández⁴, Po-Wen Chiu⁵, Hiroki Ago⁴, Arkady V. Krasheninnikov³, Kazu Suenaga²

¹Nanomaterials Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan
²The Institute of Scientific and Industrial Research (ISIR-SANKEN), Osaka University, Osaka, Japan
³Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden- Rossendorf, Dresden, Germany
⁴Global Innovation Center (GIC), Kyushu University, Fukuoka, Japan
⁵Department of Electrical Engineering, National Tsing Hua University, Hsinchu, Taiwan
⁶Department of Engineering, Tokyo Polytechnic University, Kanagawa, Japan

* Presenter:Yung-Chang Lin, email:yc-lin@aist.go.jp

The intercalation of metal species into bilayer graphene (BLG) provides a unique platform to explore atomic and electronic modifications with potential applications in energy storage. Precise atomic-scale control over these intercalated structures is crucial for understanding the fundamental physical interactions that drive changes in electronic, magnetic, and optical properties. In this study, we employ high-resolution scanning transmission electron microscopy (STEM) to probe the atomic configurations and structural dynamics of various intercalated metal chlorides (AlCl₃, CuCl₂, MoCl₅, FeCl₃) and alkali metals (K, Rb, Cs) in BLG [1-5].

Our STEM analysis reveals metal-specific atomic arrangements, including distinct interlayer spacing, bonding geometries, and periodic lattice distortions, highlighting how each metal uniquely perturbs the graphene matrix. These interactions produce notable electron redistribution and local changes in charge density, observable through spectroscopic techniques. By investigating these effects, we capture how intercalation modifies the electronic band structure of BLG, elucidating the role of charge transfer and electron localization in enhancing the physical properties of the bilayer system.

This study contributes valuable insights into the underlying physics of metal intercalation, advancing our fundamental understanding of structural and electronic transformations in layered materials. The findings lay the groundwork for engineering graphene interfaces with specific electronic and magnetic characteristics for next-generation energy applications, bridging the physics of atomic interactions with practical advances in material design.


Reference:
1. Y.-C. Lin, et al., “Polymorphic Phases of Metal Chlorides in the Confined 2D Space of Bilayer Graphene” Advanced Materials, 2105898, 1-8 (2021).
2. Y.-C. Lin, et al., “Coupling and decoupling bilayer graphene monitored by electron energy loss spectroscopy” Nano Letters, 21, 10386-10391, (2021).
3. Q. Liu, Y.-C. Lin, et al., “Molybdenum Chloride Nanostructures with Giant Lattice Distortions Intercalated into Bilayer Graphene” ACS Nano 17, 23659-23670 (2023).
4. Y.-C. Lin, et al., “Alkali metal bilayer intercalation in graphene” Nature Communication 15, 425 (2024).
5. A. V. Krasheninnikov, Y.-C. Lin, K. Suenaga, “Graphene Bilayer as a Template for Manufacturing Novel Encapsulated 2D Materials” Nano Letters 24, 12733-12740 (2024)

Keywords: TEM, Intercalation, graphene , alkali metal, metal chlorides