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

In this study, the applicability of C20 fullerene as anode material in Mg‐ion batteries was investigated by Density Functional Theory (DFT). The interaction energy of the Mg2+ ion on C20 structure was found as −147.3 kcal/mol. The HOMO‐LUMO gap value decreased during Mg interaction on C20 structure while it increased during Mg2+ interaction. The charge distributions obtained after the interactions of Mg atoms on C20 show that charge transfer has taken place. The storage capacity value of C20 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 C20 structure were computed as 1.5×10−25 and 4.61×10−4, 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 C20 fullerene structure can be used as a potential anode material in rechargeable Mg‐ion batteries. The storage capacity value of the C20 structure was calculated as 893 mAhg−1. C20 fullerene has high interaction energy and low diffusion barrier.C20 fullerene structure can be used as a potential anode material in rechargeable Mg‐ion batteries.