Investigating the Quantum Mechanical Properties of Some Carbon and Boron Nitride Nanotubes for Preparing Magnesium Ion Batteries: A Computational Study

Magnesium ion rechargeable batteries are useful for storing electrical energy because the abundance and energy density of magnesium is higher than lithium. In this research, the primary structures of the (4, 4), (5, 5) and (6, 6) single-walled carbon nanotubes were optimized using the M06-2X method and the 6-31g(d,p) basis set using Gaussian 09 program package. Then, the interaction of magnesium ion with these structures was studied to evaluate their ability to make magnesium batteries. The results show that the complexes created from these structures have good binding energies and the larger the outer diameter of the nanotubes, the more favorable the binding energy. In fact, the energy gap of these nanotubes decreases with the increase of the diameter of the nanotubes and affects their binding strength to magnesium ions. On the other hand, boron nitride nanotubes corresponding to carbon type were also optimized with a similar method and the interaction of magnesium ion with these structures was also investigated. The results show that boron nitride nanotubes with smaller outer diameters form complexes with higher binding energies with magnesium ions. In general, both types of these nanotubes are good options for preparing the anode material in magnesium ion batteries. Finally, increasing the binding energy of their complexes with magnesium ions is associated with increasing battery voltage.