Thermal Decomposition of Ternary Sodium Graphite Intercalation Compounds
Heather Au1,2, Noelia Rubio2, David J Buckley3
1Department of Chemical Engineering, Imperial College London, London, SW7 2AZ, UK.
Chemistry (Weinheim an Der Bergstrasse, Germany)
|March 7, 2020
Summary
This study reveals that sodium-GICs in solvents like THF and DMAc form stable compounds. Heating causes solvent evaporation arrested by graphene restacking, creating bubbles and expanded graphite with potential property enhancements.
Area of Science:
- Materials Science
- Chemistry
- Nanotechnology
Background:
- Graphite intercalation compounds (GICs) are precursors for graphene-related materials (GRMs).
- Solvent choice is critical for GIC formation and subsequent material properties.
Purpose of the Study:
- To investigate the formation and thermal behavior of Na-tetrahydrofuran (THF)-GIC and a novel Na-dimethylacetamide (DMAc)-GIC system.
- To understand the dynamic transformations occurring during heating of these GICs.
Main Methods:
- In situ temperature-dependent X-ray diffraction (XRD).
- Thermogravimetric analysis coupled with mass spectrometry (TGA-MS).
- Raman spectroscopy.
Main Results:
- GICs exhibit stability under ambient conditions, with Na and solvent trapped between graphene layers.
- Heating induces solvent and Na reorganization, followed by solvent evaporation.
- Graphene layer restacking arrests solvent loss, forming trapped bubbles that eventually rupture, yielding expanded graphite.
Conclusions:
- The formation of trapped solvent bubbles during GIC heating can influence material properties.
- These trapped dopants may offer property enhancements but can complicate functionalization efficiency measurements.
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