DFT study on the structure of magnesium battery anode

Batteries are one of the energy storage system that can store electrical energy and today with technological progress, they have become very important in human life and are used in various industries. Lithium-ion batteries (LIBs) is mainly used in smartphones, smart watches, laptops, etc. [۱]. While LIBs have many limitations such as economic inefficiency and low safety, researchers are looking for alternatives. Magnesium-ion batteries (MIBs) were proposed as one of the alternatives [۲]. many research has been done on the electrolyte, cathode, and anode of MIBs[۳, ۴]. In this research, we have investigated hexagonal boron nitride (h-BN) as the anode material for MIBs by using quantum espresso software based on density functional theory (DFT) calculations [۵, ۶]. The adsorption energy and diffusion barrier energy were calculated, the barrier energy which can justify the charge-discharge process on a microscopic scale and provide a wide view for experimental researches [۷-۹]. Figure ۱ shows the schematic h-BN structure from the top view and the side view (supercell ۳×۳×۱), The Mg atom absorption on the all-possible site of h-BN was investigated. It is clear that the TH site with the adsorption energy -۰.۲۶۶ eV is the most probable adsorption site, and then the TN site and TB site with the adsorption energies -۰.۲۵۸ and -۰.۲۵۶ eV respectively are the second and third suitable sites.To better understand the potential of our model structure as electrode materials, the diffusion paths and barriers of Mg on the surfaces of h-BN was studied. The barrier energy was found about ۹ meV when Mg moves in TH pathway. Therefore, it can be concluded that our proposed h-BN can be a promising anode candidate for MIBs.

Keywords:

Lithium-ion batteries , Magnesium-ion batteries , adsorption energy , boron nitride , anode