The Evaluation of Mg–Ga Compounds as Electrode Materials for Mg-Ion Batteries via Ab Initio Simulation

The Mg–Ga alloy-type electrode is one of the potential anode materials for Magnesium-ion batteries (MIBs). In this work, the thermodynamic, electrochemical and kinetic properties of Mg–Ga compounds, i.e. Mg 2 Ga 5 , MgGa 2 , MgGa, Mg 2 Ga and Mg 5 Ga 2 , have been systematically studied. Combining the first-principles calculations and charge-discharge experimental results, the structure evolution and voltage curves of Mg–Ga compounds are presented, where the Mg–Ga compounds show low voltages and high capacity up to 1922 mAh·g −1 with Mg 5 Ga 2 . Additionally, the diffusion barriers of Mg in Mg–Ga alloys are low, which is favorable for the fast ion-transmission and then good rate performance as being anodes of MIBs.