Thermal Management Material: Graphite

Graphite has pronounced anisotropy in its properties. Thermal conductivity of graphite crystal is extremely high along its layer plane, as high as 2000 Wm−1 K−1, much higher than metals, and very low across its layer plane, as low as 7 Wm−1 K−1. This anisotropy gives high possibility for graphite as thermal management materials. Here, graphite membranes with high thermal conductivity along the surface for heat dissipation and with low conductivity perpendicular to the surface for heat insulation, in addition to graphite foams as container of phase change materials for heat energy storage, are reviewed, particularly referring to the preparations of various graphite materials. Thermal conductivity of diamond crystal is also high, 2500 Wm−1 K−1, but it is very sensitive for structural defects, but that of graphitic materials is less sensitive for structural defects, suggesting that the latter is more practical for thermal management than the former. Graphite membranes with high thermal conductivity in parallel for heat dissipation and with low conductivity in perpendicular for heat insulation, in addition to graphite foams as container of phase change materials for heat energy storage, are reviewed, referring to their preparation. Thermal conductivity of graphitic materials is less sensitive for structural defects, suggesting practical possibility for thermal management.