Preparation and Characterization of Li-Ion Graphite Anodes Using Synchrotron Tomography

Area of Science:

• Materials Science
• Electrochemistry
• Imaging Techniques

Background:

• Lithium-ion (Li-ion) cells are critical energy storage devices.
• Understanding anode microstructure is key to improving Li-ion cell performance and longevity.
• Current microstructure analysis methods can be time-consuming and data-intensive.

Purpose of the Study:

• To present an efficient multi-layer preparation method for synchrotron tomography analysis of Li-ion cell anode active material.
• To enable detailed microstructure characterization of both pristine and aged Li-ion cell components.
• To investigate the impact of aging on anode microstructural properties.

Main Methods:

• A novel multi-layer stacking technique for synchrotron tomography sample preparation.
• Detailed procedures for cell disassembly (pouch and cylindrical), layer selection, and component separation (graphite-compound and current collector).
• 3D volume analysis including calculation of porosity, tortuosity, and specific surface area.

Main Results:

• The stacking method allows parallel measurement of up to ten layers without compromising image resolution or quality.
• Significant differences in tortuosity and specific surface area were observed between aged and pristine Li-ion anode materials.
• Porosity remained relatively constant, indicating localized changes in material structure upon aging.

Conclusions:

• The proposed multi-layer synchrotron tomography approach significantly enhances data acquisition efficiency for Li-ion anode microstructure analysis.
• This method effectively reveals microstructural degradation mechanisms in Li-ion cells, particularly changes in tortuosity and specific surface area.
• The technique facilitates comprehensive assessment of material homogeneity and aging effects within Li-ion cells.