Adsorption and diffusion of magnesium on nitrogen-doped Mo2C monolayer.

Kaimin Fan,Jiangfeng Ni,Jing Tang

doi:10.1007/s00894-021-04958-z

Abstract

The Mg adsorption and diffusion behaviors on nitrogen-doped (N-doped) Mo2C monolayer have been investigated by the first principles based on density functional theory (DFT). To investigate the effect of nitrogen concentration on adsorption energies, Mo2C1-xNx (x=0.0625, 0.125, 0.1875, and 0.25) with four different nitrogen doping concentrations have been considered in the present work. The results show that N-doped Mo2C is benefit for Mg adsorption. In particular, when the doping concentration reaches to 14.29%, the adsorption energies of Mg on Mo2C0.875N0.125 are in the region between -1.639 and -1.517 eV, e.g., the adsorption energies of Mg on TC1 and H2 sites are -1.639 eV and -1.625 eV, which are decreased by 16.49% and 18.43% as compared with the pristine Mo2C. The calculations on diffusion behaviors show that the Mg diffusing between two adjacent favored sites via a high-symmetry site along H3-B-H4 and H1-B-H1 paths possesses the barriers of 0.021 eV and 0.028 eV. Additionally, the partial density of states (PDOS) reveals the interaction between Mg and Mo2C0.875N0.125, and indicates that nitrogen doping causes the PDOS peaks transfer to a lower energy level, which is benefit for the bonding between Mg and Mo2C0.875N0.125. These results suggest that the adsorption and diffusion behaviors of Mg have been enhanced by nitrogen doping.

Highlights

Lithium ions batteries (LIBs) are widely used to in phones, laptops, digital cameras, and other portable devices [1,2,3]
The Mg adsorption and diffusion behaviors on nitrogen doped (N-doped) Mo2C monolayer have been systematically investigated by the first principles based on density functional theory (DFT)
The results show that nitrogen doping is a positive approach to decrease the diffusion barriers, which is beneficial to the diffusion of Mg on Mo2C0.125N0.875

Summary

Introduction

Lithium ions batteries (LIBs) are widely used to in phones, laptops, digital cameras, and other portable devices [1,2,3]. Safety, high costs and resource shortages have restricted the development of lithium batteries [4, 5]. With the development of the intelligent electronic applications such as new energy vehicles, energy storage plant and artificial satellite, which require high battery storage and stable cycle capacity. MIBs have been considered as the potential alternatives to LIBs, due to the natural abundance, low cost, safety and high volumetric energy density (3832 mAh cm− 3) [6, 7]. It is well-known that the performance of rechargeable batteries depends on their anode or cathode materials. A great deal of efforts has been carried out to search for novel anode materials for MIBs

Methods

Results

Conclusion