1D/2D C3N4/Graphene Composite as a Preferred Anode Material for Lithium Ion Batteries: Importance of Heterostructure Design via DFT Computation.

Abstract

Graphene is commonly used to improve the electrochemical performance of electrode materials in rechargeable batteries by forming graphene-based heterostructures. Two-dimensional graphitic carbon nitride (C3N4) is an analogue of graphene, and it is often used to form 1D/2D and 2D/2D C3N4/graphene heterostructures. However, a theoretical understanding of the heterointerface in these heterostructures and how this affects their electrochemical performance is lacking. In this work we study the heterointerface of 1D/2D and 2D/2D C3N4/graphene heterostructures and how the different dimensions influence the lithium ion battery performance of the heterostructure. Our density functional theory (DFT) study showed that the common problem of C-N bond breakage experienced in 2D/2D C3N4/graphene heterostructure does not occur in the 1D/2D heterostructure. Furthermore, the 1D/2D heterostructure showed superior conductivity in comparison to that of the 2D/2D heterostructure of C3N4/graphene. The 1D/2D C3N4/graphene heterostructure also recorded a high theoretical capacity and rapid charge transfer. These results suggest that the properties of a heterostructure are influenced by the dimension of materials at the interface. These discoveries on the relationship between material dimension in heterostructure electrodes and their electrochemical performance will motivate the design of advanced electrode materials for rechargeable batteries.