A Density Functional Theory Study on Rechargeable Mg-ion Batteries: C20 Fullerene as a Promising Anode Material

Abstract

In this study, the applicability of C-20 fullerene as anode material in Mg-ion batteries was investigated by Density Functional Theory (DFT). The interaction energy of the Mg2+ ion on C-20 structure was found as -147.3 kcal/mol. The HOMO-LUMO gap value decreased during Mg interaction on C-20 structure while it increased during Mg2+ interaction. The charge distributions obtained after the interactions of Mg atoms on C-20 show that charge transfer has taken place. The storage capacity value of C-20 structure was calculated to be 893 mAhg(-1). The diffusion barrier was calculated as 1.9 kcal/mol. In addition, the diffusion coefficient for Mg and Mg2+ on C-20 structure were computed as 1.5x10(-25) and 4.61x10(-4), respectively. Consequently, the high storage capacity, high conductivity and low diffusion barrier for discharge/charge process and the suitability of the diffusion coefficient suggest that C-20 fullerene structure can be used as a potential anode material in rechargeable Mg-ion batteries.