Point Defects Enhance Cross-Plane Thermal Conductivity In Graphite.
Ke Shen1,2,3,4, Qi Ren5, Lu Zhao2
1College of Materials Science and Engineering, Hunan University, Changsha, 410082, China.
Advanced Materials (Deerfield Beach, Fla.)
|February 24, 2025
Summary
Energetic particle irradiation unexpectedly doubled graphite's thermal conductivity by introducing spiro interstitial defects. These defects enhance phonon propagation, improving heat transfer in layered materials.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Nanotechnology
Background:
- Point defects typically decrease thermal conductivity (κ) by scattering phonons.
- This mechanism is crucial for controlling heat transfer in materials.
Purpose of the Study:
- To investigate the effect of point defects on graphite's thermal conductivity.
- To understand the underlying mechanism of any observed changes in heat transfer.
Main Methods:
- Energetic particle irradiation of graphite.
- Measurement of cross-plane thermal conductivity (κ).
- Integrated differential phase contrast imaging with scanning transmission electron microscopy (STEM-iDPC).
Main Results:
- Point defect introduction via irradiation nearly doubled graphite's cross-plane κ (from 10.8 to 18.9 W m⁻¹ K⁻¹).
- Spiro interstitial defects were identified as the cause.
- These defects enhance phonon propagation by bridging basal planes, increasing phonon group velocity and reducing scattering.
Conclusions:
- Lattice defects can unexpectedly enhance thermal conductivity in layered materials.
- Spiro interstitials offer a novel mechanism for improving heat transfer.
- This finding has implications for thermal management in demanding environments, such as those with high radiation.
