Research On Electronic,Mechanical Properties And Energy Storage Behavior Of Carbon-Based Two-Dimensional Heterostructure

Two-dimensional materials have attracted much attention due to their diverse physical and chemical properties.However,with the increasing demand on the diversity of material performance,traditional two-dimensional materials cannot meet people's needs.Van der Waals heterostructure achieves complementary advantages by stacking different two-dimensional materials vertically by van der Waals force,which opens up a new direction for the research of new two-dimensional materials.In this study,the crystal structure,electrochemical and mechanical properties of graphene/antimonene heterostructures and graphyne/antimonene were systematically studied by first principles calculation method and ab initio molecular dynamics simulation.On this basis,the lithium storage properties of these two kinds of two-dimensional heterostructures as anode materials of lithium-ion batteries were compared.The main work and contents are as follows:(1)The electrical and mechanical properties of graphene/antimonene heterostructures and graphyne/antimonene heterostructures were calculated by first principles calculation.The calculated results of electronic density of states show that these two kinds of carbon-based heterostructures with antimonene are metallic.The strain-stress graph shows that the mechanical properties of these two carbon-based heterostructures are improved compared with single layer antimonene.The calculated results of band structure under strain indicate that the band gap of graphene/antimonene heterostructure is opened at the beginning of strain.With the increase of strain,the band gap decreases gradually,and returns to zero when the strain reaches 15%.The energy band structure of graphyne/antimonene heterostructure has no obvious change under strain.The results of molecular dynamics simulation show that the crystal structures of the two heterostructures have no obvious deformation and no chemical bond fracture occurs after 10 ps simulation at 300 K and 500 K,which indicates that these two heterostructures have good thermodynamic stability at room temperature and high temperature.(2)The calculation of lithium storage performance shows that lithium can be stably adsorbed in the two heterostructures.Compared with the adsorption energy on the surface layer of heterostructures,the adsorption energy of lithium adsorbed on the interlayer of heterostructures is higher,which indicates that lithium ion is more inclined to be adsorbed in the interlayer of heterostructures.The calculation of the diffusion behavior of lithium on the heterostructures shows that lithium has the lowest diffusion energy barrier and the best diffusion performance on antimonene.The diffusion performance of lithium on graphene is the second,and that of graphyne is the worst.At the same time,the diffusion energy barrier of lithium in the heterostructures interlayer is significantly lower than that in the surface,and the formation of heterostructures improves the rate performance of the electrode.