High concentration magnesium borohydride/tetraglyme electrolyte for rechargeable magnesium batteries

High concentration magnesium borohydride/tetraglyme electrolyte for rechargeable magnesium batteries is simply prepared by dissolving inorganic magnesium salt Mg(BH 4 ) in tetraglyme (TG) ether solvent with good safety. 90 °C heating treatment is performed in the preparation process and LiBH 4 as a chelating agent is added to improve the electrochemical performance. Mg deposition–dissolution performance and the electrochemical window of the electrolyte on non-inert stainless steel (SS), nickel (Ni), copper (Cu) electrodes and inert platinum (Pt) electrode are systematically studied by cyclic voltammetry and constant current discharge–charge measurements. 0.5 mol L −1 heated Mg(BH 4 ) 2 /LiBH 4 /TG ([LiBH 4 ] = 1.5 mol L −1 ) solution shows good electrochemical performance with 2.4 V ( vs . Mg RE) anodic stability on stainless steel, close to 100% Mg deposition/dissolution efficiency and high cycling reversibility . Furthermore, the reversible electrochemical process of Mg intercalation into Mo 6 S 8 cathode with excellent cycling performance in the electrolyte indicates the feasible application in rechargeable magnesium batteries.