Simulation of the Adsorption and Diffusion of Lithium Atoms on Defective Graphene for a Li-Ion Battery

Abstract

Based on the density functional theory (DFT) with allowance for spin polarization or the local spin density approximation (LSDA), we calculate the adsorption and diffusion properties of a lithium atom on a graphene ( ) monolayer with monovacancy ( ) as the anode material for an -ion battery. The DFT LSDA calculations are performed in relaxed 5 × 5 and 6 × 6 supercells and based on graphene with the monovacancy + lithium adatom complex . Based on the calculated values of the adsorption energy of the lithium atom , the energetically stable location of the lithium adatom is determined on a monolayer of supercells in and . The calculation results show that the adatom energetically prefers to be adsorbed in the pit position (H-site) rather than adsorbed from above (T-site) of the carbon atom in the monolayer. The DFT LSDA calculated electronic band structure and local total and partial magnetic moment of supercell atoms are consistent with the calculations performed by the generalized gradient approximation (GGA)-PBE functional for the H-, B-, and T-sites of graphene. Taking into account the experimentally obtained diffusion coefficients of lithium in two-layer graphene in the struc-tural packing of an AB package and the temperature (263–333 K) dependence of Li diffusion in two-layer graphene, which is described by the Arrhenius law, the diffusion activation energy of is calculated at con-centrations of = 0.06–0.51 in LixC12 graphene in the AB packaging.