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. Mg2Ga5, MgGa2, MgGa, Mg2Ga and Mg5Ga2, 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 center dot g(-1) with Mg5Ga2. 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.