Quest for Nanocrystal Spinel Oxides As Prospective Cathodes for Next-Generation Magnesium Batteries

Abstract

Rechargeable batteries based on the intercalation of multivalent cations are a promising energy storage technology to overcome the limitations of safety, cost, and energy density of state-of-the-art Li-ion batteries. However, functionality of cathodes in Mg batteries has only been realized with a few of S-containing compounds, which possess limited capacity and operate at low potential, hindering competitive energy densities. Spinel oxides have been predicted to improve both voltage and capacity. However, the strong electronic interaction between these cations and the corresponding frameworks impose the challenge of Mg2+ low mobility and sluggish kinetics.Herein, a series of spinel oxides with designed sizes and defects have been evaluated as possible cathodes, studying their fundamental ability to intercalate Mg2+ by using different temperatures. Mg2+ deintercalation at high voltage was achieved at 110oC, and, under certain conditions, even at room temperature. In addition, the capabilities of Mg2+ reversible intercalation are correlated to particle size. Our results demonstrate that the design of nanosized spinel oxides could enable an efficient pathway to improve Mg2+ reaction kinetics, thus advancing the ability to develop new multivalent cathode protypes with high energy density.