Understanding heat transport in solids is essential for controlling thermal processes in energy materials. Noncrystalline solids exhibit complex temperature-dependent thermal conductivities, with heat transport mechanisms that remain debated. Structural disorder suppresses extended phonons, suggesting that localized vibrations dominate thermal transfer, while the intrinsic complexity of these disordered atomic structures has long hindered theoretical modeling. Glassy carbon, a nongraphitizing carbon featuring disordered and randomly oriented graphitic nanodomains, exemplifies this challenge. Here, we construct realistic atomic-scale models of glassy carbon up to 15 nm in size and employ nonequilibrium molecular dynamics simulations to study their thermal conductivity. Our simulations reveal that local thermal conductivity correlates with the orientation of graphitic nanodomains. By controlling this orientation, an extended range of thermal conductivities can be achieved, making glassy carbon a promising material for thermal management in batteries, spanning the low-conductivity regime of phase change materials to the high-conductivity range of carbon fiber composites.
Tomás et al. (Mon,) studied this question.