Magnesium Deintercalation From the Spinel-Type MgMn2-yFeyO4 (0.4≤y≤2.0) by Acid-Treatment and Electrochemistry

Abstract

Rechargeable magnesium batteries attract lots of attention because of their high safety and low cost compared to lithium batteries, and it is needed to develop more efficient electrode materials. Although MgMn2O4 is a promising material for the positive electrode in Mg rechargeable batteries, it usually exhibits poor cyclability. To improve the electrochemical behavior, we have prepared nanoparticles of MgMn2-yFeyO4. The XRD results have confirmed that when Mn3+ (Jahn-Teller ion) ions are replaced by Fe3+ (non-Jahn-Teller ion), the resulting MgMn2-yFeyO4 is a cubic phase. The structure and theoretical voltage are theoretically calculated by using the DFT method. The obtained samples have been chemically treated in acid solution for partial demagnesiation, and it is observed that the presence of iron inhibits the deinsertion of Mg through disproportionation and favors the exchange reaction. The electrochemical behavior in non-aqueous magnesium cells has been explored.