The Inhibition Mechanism of Lithium Dendrite on Nitrogen-Doped Defective Graphite: The First Principles Studies

Abstract

The initial Li-ions nucleation on the basal plane of graphite anode with N-doped defects during the charge progress of lithium-ion battery was investigated theoretically by first-principle calculations using double-layered graphene (DLG) model. Based on the geometric structure optimization, the Li-ions are found to be accumulated on the top surface of N-doped DLG with single vacancy defect (SV-3N) in the near 2D structure. Also for the N-doped DLG with double vacancy defect (DV-4N), the Li-ions are deposit on its top surface, as well as could enter the interlayer space. The electronic analysis proves the ion character of Li layer. Therefore, the initial Li-ions nucleation on the basal plane of graphite with both N-doped SV and DV defects can be suppressed with different detailed mechanisms. The calculation of diffusion energy and lithiation potential shows that the Li-ions nucleation is inhibited via an adsorption-like and intercalation-like process on the DLG with SV-3N and DV-4N, respectively. Additionally, the calculated adsorption energy suggests that more Li atoms are adsorbed due to the presence of N, and thus the capacity of N doped graphite anode can be enhanced accordingly.