The Effect of the Solvation Ability Towards Mg2+-ion on the Kinetic Behavior of Mg3Bi2 Electrode

Abstract

Intermetallic compounds are expected to be used as the negative electrode for Mg-ion batteries, due to their relatively large capacity and the excellent electrochemical performance in the non-ethereal solutions. In the present study, the reaction mechanism of Mg3Bi2 is focused. By comparing the reactivity towards the same electrode sheet in various electrolyte solutions, it is found that the effect of MgF2 based surface film, which is formed by the decomposition of Mg(N(CF3SO2)2)2 (Mg(TFSA)2), is not large necessarily. The reactivity in Mg(TFSA)2+crown ether/acetonitrile solution fairly varies by the size of crown ethers. From the results, it is indicated that the de-solvation process will also be the critical factor for the Mg2+-ion insertion/extraction into the Mg3Bi2 electrode.