Thermophysical properties of thermally expanded graphite

We studied the thermophysical and electrical properties of thermally expanded graphite in the temperature range of $300$ to $800$ K and found that the phonon contribution to heat transfer processes is dominant in this material. The temperature dependence of the mean free path of phonons is determined. The temperature dependences of the specific heat $C_p$, thermal conductivity, and electrical conductivity revealed weak anomalies in the temperature range of $550$ to $600$ K. The thermal conductivity in thermally expanded graphite is two orders of magnitude lower than in ordinary graphite and three orders of magnitude lower than in graphene and carbon nanotubes.