Engineering Ultrahigh Thermal Conductivity in Buckling Structure by Activating Lone Pair Electrons

High thermal conductivity (κ) is critical for the thermal management of nanoelectronics, as efficient heat dissipation underpins device stability and performance. Carbon nitride (CN) compounds are promising two-dimensional (2D) materials with tunable structures, low cost, facile synthesis, excellent optical properties, and wide bandgaps, yet achieving high κ is hindered by the buckled structures breaking reflection symmetry, the lone pair-bonding electron interactions enhancing anharmonicity, and the long-neglected four-phonon scattering, which are pivotal factors for high κ. Herein, we address these challenges in 2D buckled c-CN via atomic-scale coordination environment optimization and electronic structure regulation, where the unique lone pair electron coordination induces buckling while mitigating lone pair-bonding electron interactions to maintain low anharmonicity. As a result, the c-CN exhibits an ultrahigh κ of 1359 W/mK (three-phonon scattering) and retains 708 W/mK even with four-phonon scattering included, confirming it as a high-κ CN material. This study could provide guidance for atomic-level structure and electronic structure design of high-κ 2D materials for nanoelectronic heat dissipation.