Computational Study of the Interaction between Alkali Metal Ions and Graphene by $\text{DV}-\mathrm{X}\alpha$ Method

Aiming to develop negative electrode materials for secondary batteries, we investigated the interaction between Li
⁺
, Na
⁺
and K
⁺
alkali metal ions, and graphene using
$\mathbf{DV}-\mathbf{X}\boldsymbol{\alpha}$
method. The BOP results confirmed that there are weak interactions between alkali metal ions and graphene cluster. The density of states of graphene and alkali metal ions were also calculated with
$\mathbf{DV}-\mathbf{X}\boldsymbol{\alpha}$
. From these results, it was suggested that not only electrostatic interactions, but also the effects of orbital overlap between graphene and alkali metal ions cannot be ignored. Calculations by
$\mathbf{DV}-\mathbf{X}\boldsymbol{\alpha}$
in our study could be completed within a few minutes per structure showing that
$\mathbf{DV-X}\boldsymbol{\alpha}$
is a very practical method in material design. Furthermore, we also investigated a system where a carbon atom in graphene cluster was replaced with a silicon atom, and then calculated the interaction between alkali metal ions and the graphene cluster. We found that it is possible to control the strength of the interaction between alkali metal ions and graphene by adjusting the silicon substitution concentration.