Development of Oxide-Type Cathode Materials towards Room-Temperature Magnesium Rechargeable Batteries

Abstract

Magnesium rechargeable batteries (MRBs) are ones of promising low-cost, safe, and high-energy post-lithium-ion batteries. However, critical issues still lie both in electrolytes and cathodes, despite 20 years that have passed since the first report of prototype MRB. Difficulty in the utilization of high-energy oxide-type cathode materials derives from their low ion-diffusion and electrical conductivity, leading to low reversible capacity. Herein, various nanotechnologies for spinel oxide cathode materials and cathode/electrolyte interface are displayed to operate the MRB, even at room temperature conditions. Surface-modified ultraporous spinel nanoparticles exhibit electrochemical magnesium intercalation, achieving the theoretical capacity. In addition, the decomposition reaction of the ether-based electrolyte at the highly reactive cathode surface is suppressed by the Mg²⁺-conductive coating layer. These cathode material designs will open up new technologies for the practical application of room-temperature MRB.