The Li ion transport behavior in the defect graphene composite Li3N SEI: a first-principle calculation

Abstract

An artificial solid electrolyte interface (SEI) of a graphene composite lithium salt can inhibit the growth of dendrites by driving the lithium deposition behavior on the surface of the lithium metal anode. The first-principle method was used to calculate the graphene/lithium nitride SEI, including the structural form and stability of intrinsic (G-Li3N), single-vacancy defect (SVG-Li3N), and double-vacancy defect (DVG-Li3N) graphene heterostructure. The adsorption and migration behavior of lithium ions on the heterostructure surface and the interface were also calculated. This study showed that the modification of double-vacancy defect graphene improved the stability of the heterostructure, and the adhesion work of the composite SEI is the highest. The modification of defective graphene increases the adsorption energy of lithium atoms on the surface and interface of the heterostructure: the strongest adsorption of Li atoms on the single-vacancy defect region of the heterostructure, the opposition migration pathway of Li atoms on the surface and interface of the DVG-Li3N heterostructure, and the decrease diffusion energy of Li atoms on the surface and interface of the DVG-Li3N heterostructure. A composite layered SEI of graphene and Li3N was constructed to inhibit dendritic growth by adjusting the deposition behavior of lithium atoms.