The temperature-dependent thermal conductivity of pressure-sintered graphene-ceramic matrix composites

In graphene-ceramic matrix composites (GCMC) prepared via pressure-assisted sintering, graphene fillers are typically aligned perpendicular to the pressure axis, leading to higher thermal conductivity along the alignment direction. However, theoretical predictions of thermal conductivity remain challenging due to multiple influencing factors, including interfacial thermal resistance, filler orientation, and ambient temperature. This study develops a multi-scale model that integrates molecular dynamics simulations and effective medium theory to account for these factors. Specifically, at the atomic scale, molecular dynamics simulations are used to precisely calculate the temperature-dependent interfacial thermal resistance between graphene and ceramics. At the mesoscale, a Gaussian distribution model is employed to characterize the orientation distribution of graphene fillers, with parameters optimized through experimental validation. Finally, the macroscopic temperature-dependent thermal conductivity of GCMC is determined through effective medium theory. The model's accuracy is validated against multiple experimental data, revealing the significant impact of ambient temperature on interfacial resistance and the temperature-dependent thermal transport mechanisms in GCMC.