Density Functional Theory Calculations on Three-Dimensional Dirac Semimetal Graphyne as Anode Nanomaterials for Li-Ion Batteries

Recently, three-dimensional (3D) graphyne has been reported as a promising anode nanomaterial for lithium-ion batteries (LIBs), while its structure remains unknown. In this study, two types of 3D graphyne were constructed by inserting acetylenic linkages between the buckled graphene nanoribbons. State-of-the-art theoretical calculations were used to confirm their stability in terms of energy, dynamics, and thermodynamics. Moreover, both the armchair and zigzag architectures exhibit anisotropic Dirac points with high Fermi velocities in their band structures. By incorporating these excellent characteristics, 3D graphyne demonstrates great application potential in LIBs with high capacities and low diffusion barriers. In particular, the high capacity of Li-ions in 3D graphyne has reached up to 1005 mA h g –1, nearly three times greater than that of commercial graphite. These intriguing results not only expand graphene from 2D to 3D with novelty but also enhance the applications of graphyne as anode nanomaterials for LIBs.