Mg ion dynamics in anode materials of Sn and Bi for Mg-ion batteries

Based on density functional theory computation, we systematically investigated diffusion behavior of Mg ions in β-tin (Sn), bismuth (Bi), and their magnesiation compounds of Bi2Mg3 and Mg2Sn. Results showed that the β-Sn and Bi are good candidates for the anode materials for Mg ion batteries with small diffusion barriers. The dynamic simulations and the obtained energy barriers showed that compared with β-Sn, Bi is a better anode candidate with fast charge/discharge rates for the Mg ion batteries.