Spray-Dried MgMn₂O₄ Spinel Oxide Cathode with Single Mg Ion-Conductive Polymers for Rechargeable Mg Metal Battery

Abstract

To improve the cycle performance of Mg metal batteries, a spinel-type MgMn2O4 (MMO) as the active material of the cathode was coated with a poly­(styrene-4-sulfonyl trifluoromethylsulfonyl)­imide Mg salt (PSTFSI-Mg) on the MMO surface. Coating was performed by spray drying, freeze drying, simple mixing, and one-pot spray drying. Transmission electron microscopy measurements of the resulting polymer-coated MMO were undertaken to verify the surface and the inner morphology. The results of charge–discharge measurements suggest that the polymer coating on the MMO surface promotes electron transfer between the particles. These results are interested in terms of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) of the modified polymers obtained from density functional theory (DFT), confirming that the polymer reduces the gap between the valence band maximum of MMO and the HOMO level of the electrolyte solution, suppressing the degradation of the electrolyte.

Research and Development of Novel Secondary Batteries in Japan

“…While promising, these approaches suffer from several fundamental and technical problems. The VSI reports significant achievements for the Mg-metal batteries in developing new electrolytes and electrode active materials through collaboration between material scientists and computational scientists in Japan. − The VSI describes extensive studies on the elucidating mechanisms of oxygen electrode reaction, developing electrode materials and solvents, and establishing cell design strategies for the practical implementation of Li–O 2 batteries. − …”