Li decorated graphdiyne nanosheets: A theoretical study for an electrode material for nonaqueous lithium batteries

Abstract

In this work, Density Functional Theory (DFT) is used to study pristine and defectiveGDY. We investigate the effect of Li atom adsorption on the electronic and structuralproperties of this 2D material. In both cases, the Li atom is located at the corner of thetriangular-like pore (H1), but with a slight shift for the defective system. In the perfectsystem, the Li-C bond distances range from 2.289 Å to 2.461 Å, while in the defectivecase, they range from 2.237 Å to 3.184 Å. In the perfect case, the GDY-Li systembecomes metallic and the Li 2s states are stabilized. Charge transfer to the surfacesoccurs near the vicinity of the Li atom. The C vacancy generates new C=C bonds similarto double bonds, enhancing the interaction with Li through strong conjugation. After Liadsorption, the sum of bond order for all the C atoms increases in both structures,from 0.4% to 6%. The Li storage capacity without significant restructuring is six Liatoms. When the atom concentration increases, the OCV values for Li decrease from 0.93 V to 0.23 V. For defective GDY, the specific capacity is 788 mAhg-1, which isslightly higher than for pristine case.