The Effect of the Cyclic Ether Additives to the Ethereal Electrolyte Solutions for Mg Secondary Battery

The effect of crown ether additives for the electrolyte solution containing Mg(N(CF3SO2)2)2 (Mg(TFSA)2) was studied. Mg(TFSA)2 salt hardly dissolved in tetrahydrofuran, while 1 mol dm−3 solution was obtained by 18-crown-6 (18C6) ether addition and the 10−3 S cm−1 order of ionic conductivity was achieved. From the FT-IR spectrum, the predominantly coordination between Mg2+-ion and 18C6 was indicated. Cyclic voltammogram showed the redox current, which indicated that the reversible Mg plating and stripping reaction took place, while the clear redox current did not appear in the additive-free solution. From the results, we concluded the specific solvation structure of Mg2+-ion by 18C6 ether would play the effective role for the reversible Mg plating and stripping reaction.