The electrochemical performance of MoO 3 nanosheets as high-voltage cathode materials for magnesium-lithium hybrid batteries

Abstract Magnesium-based batteries, particularly magnesium-lithium hybrid batteries, have emerged as a promising avenue for next-generation high-performance energy storage technologies, owing to the low cost and high safety of magnesium resources, as well as the rapid kinetic properties of lithium ions. However, the relatively low operating voltage of magnesium-lithium hybrid batteries has limited their widespread application. To address this limitation, this work develops a MoO 3 nanosheet cathode, which demonstrates a high operating voltage of 1.62 V during discharge and exhibits minimal charge-discharge polarization. Furthermore, at a current density of 50 mA g −1 , the battery delivers a high discharge capacity of 163.2 mAh g −1 , with a capacity retention of 71.6% after 500 cycles. By integrating the ex-situ characterizations with the first-principles calculations, we demonstrate that MoO 3 in the magnesium-lithium hybrid system operates via a dual-cation synergistic storage mechanism, in which Li + plays the dominant role while Mg 2+ participates reversibly. These results indicate that MoO 3 nanosheets are promising as high-voltage, low-polarization cathode materials for magnesium-lithium hybrid batteries, offering both a viable materials platform and a sound mechanistic foundation for the development of high-performance magnesium-lithium hybrid energy-storage systems.