Significantly reduced c-axis thermal diffusivity of graphene-based papers.
Meng Han1, Yangsu Xie2, Jing Liu3
1Department of Mechanical Engineering, 2010 Black Engineering Building, Iowa State University, Ames, IA 50011, United States of America.
Nanotechnology
|April 6, 2018
Summary
This study investigates the thermal properties of graphene-based papers, finding that defects limit heat transfer. Optimizing graphene nanostructures is key for effective thermal management materials.
Area of Science:
- Materials Science
- Nanotechnology
- Thermal Engineering
Background:
- Graphene-based films/papers offer high thermal conductivity and surface-to-volume ratio.
- They are considered for lightweight thermal interface materials and lateral heat spreaders.
- Understanding their cross-plane thermal properties is crucial for material optimization.
Purpose of the Study:
- To investigate the cross-plane thermal conductivity (k_c) and diffusivity (α_c) of partially reduced graphene paper (PRGP) and graphene oxide paper (GOP).
- To compare the thermal properties of PRGP and GOP with highly-reduced graphene paper and graphite.
- To elucidate the factors influencing thermal transport in these graphene-based materials.
Main Methods:
- Experimental determination of cross-plane thermal diffusivity (α_c) for PRGP and GOP across a temperature range (12-295 K).
- Analysis of material structure, including grain size and defect density, to correlate with thermal transport.
- Comparative analysis with other graphene-based materials and graphite.
Main Results:
- PRGP exhibited low α_c attributed to phonon scattering from grain boundaries and defects.
- GOP showed limited cross-plane thermal transport due to functional groups hindering direct energy coupling between layers.
- Thermal transport in GOP is described as occurring through "weak thermal transport tunnels".
Conclusions:
- Defects and functional groups significantly impact the thermal performance of graphene-based papers.
- PRGP and GOP demonstrate limitations in cross-plane thermal transport compared to highly-reduced graphene.
- This research provides insights for tailoring graphene nanostructures to achieve desired thermal properties for advanced applications.
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