Exploring the feasibility of monolayer Mg2N as an anode material for alkali metal ion batteries: A first principle calculation

Abstract

To meet the growing demand for energy storage devices, anode material with good electrochemical performance is urgently needed. In view of the lighter anode material contributing to high specific capacity, this study examines the feasibility of Mg2N monolayer as an anode material for alkali metal ion batteries based on the first principle calculations. A comprehensive study was carried out which includes the stability, electronic properties and electrochemical performance for Li/Na/K-ion batteries (LIBs/NIBs/KIBs). The results of phonopy spectrum and ab initio molecular dynamics (AIMD) calculations demonstrated that monolayer Mg2N possesses high dynamic and thermal stability. The electronic band structure and density of states indicated the superior conductivity of Mg2N, ideal for the use of electrode material. The calculation of electrochemical performance revealed that Mg2N exhibits ultra-high theoretical specific capacities of 2140 mAh g−1 and 863 mAh g−1 as an anode material for LIBs and NIBs that far surpass the specific capacities of graphite. The low diffusion barrier (both below 0.01 eV for LIBs/NIBs) ensures fast ion transport during the charging/discharging process. The aforementioned results suggested that Mg2N shows the potential as a promising anode material for LIBs and NIBs. This work may guide the design of anode material for alkali metal ion batteries.