▎ 摘　　要

Graphene+, a novel carbon monolayer with sp2-sp3 hybridization, was recently reported to exhibit unprece-dented out-of-plane half-auxetic behavior and graphenelike Dirac properties [Yu et al., Cell Rep. Phys. Sci. 3, 100790 (2022)]. Herein, based on comprehensive state-of-the-art first-principles calculations, we reveal the significant effect of softened sp2-sp3 bonding on the lattice thermal transport in graphene+. At room temperature, the thermal conductivity (K) of graphene+ is obtained as similar to 170 W/mK, which is much lower than that of graphene (similar to 3170 W/mK). It is found that the softened sp2-sp3 bonding significantly suppresses the vibrations of acoustic phonons in graphene+, which leads to strong anharmonicity and weak phonon hydrodynamics. Thus, the large reduction in K stems from the softened sp2-sp3 bonding network. Our study provides fundamental physical insights into the thermal transport properties of graphene+, which would provide prospective guidance for the promising application in the field of thermal management.