Molecular investigation of thermal conduction and local phonon transport in graphene aerogels

Abstract

Graphene aerogels (GA), renowned for their exceptional mechanical and structural features, have garnered increasing attention for their unique thermal properties. By employing molecular dynamics (MD) simulations and phonon calculations, this study systematically investigates the relationship between thermal conductivity and local phonon transport behaviors of GA and its key structural parameters—including the average length and curvature of graphene sheets, pore diameter, density, porosity, tortuosity, carbon bond density, and specific surface area. The results reveal that increased graphene sheet curvature shifts localized phonon transport toward higher frequencies, diminishing thermal transport efficiency. Higher porosity further decreases thermal conductivity, whereas longer graphene sheets and higher carbon bond densities enhance heat conduction. Additionally, by incorporating new morphological descriptors into empirical equations for density- and porosity-dependent thermal conductivity of GA, the prediction accuracy improved by approximately 22% and 51%, respectively. These findings provide a reliable framework for evaluating, predicting, and optimizing the thermal performance of GA-based materials alongside other features, advancing their design and application space in thermal management and energy systems.