Effect of Na-ion intercalation on the thermal conductivity of carbon honeycomb nanostructure

This work studies the thermal conductivity of Na-ion intercalated carbon honeycomb (CHC) via the combination of first-principles calculation and molecular dynamics simulation. The effects of ion concentration, ion charge, temperature, and strain are explored. The simulation results show that the thermal conductivity of CHC presents a nonmonotonic dependence on the ion concentration. The enhanced phonon scattering and increased phonon group velocities of CHC induced by its interaction with the Na ions are responsible for the nonmonotonic dependence. Both the increases in the ion charge and temperature reduce the thermal conductivity. In contrast, a compressive strain of around -3% can increase the thermal conductivity by eliminating the phonon softening effect caused by the volume expansion of CHC during the ion intercalation. However, further increasing the strain negatively or positively from -3% leads to a decrease in the thermal conductivity. The simulation results presented in this work are beneficial in understanding the thermal properties of CHC when it is used as an electrode in ion batteries and supercapacitors.