Improved Transport Properties and Novel Li Diffusion Dynamics in van der Waals C2N/Graphene Heterostructure as Anode Materials for Lithium-Ion Batteries: A First-Principles Investigation

Abstract

In this paper, we report a theoretical investigation of the electronic structures, electron/phonon transport properties, and electrochemical parameters of the C2N/graphene bilayer. The p-type C2N/graphene bilayer, with a direct band gap of 0.2 eV at Γ-point, exhibits promising electric conductivity similar to that of the graphene monolayer. In addition, it also shows excellent lattice thermal conductivity of 1791.1 W/m·K, compared to 82.22 W/m·K of the C2N monolayer. The theoretical capacity of C2N/graphene in Li-ion batteries is found to be 490.0 mA h/g. For Li diffusion, the energy barriers for the energetically favorable diffusion pathways are found to be in the range of 0.2–0.5 eV for both C2N monolayer and C2N/graphene bilayer. The planar diffusion coefficients of the Li atom on C2N and C2N/graphene materials are predicted to be 2.97 × 10–11 and 4.74 × 10–11 m2/s at 300 K, respectively, comparable with that of the graphene monolayer. With the help of first-principles molecular dynamics (FPMD) simulat...