Carbon-Coated NaTi₂(PO₄)₃ Nanocubes as a High-Voltage Cathode for High-Performance Magnesium–Lithium Hybrid Batteries

The magnesium–lithium hybrid battery leverages the synergistic benefits of a Mg metal anode and a high-performance Li-ion cathode, significantly enhancing the energy density. However, the high-voltage cathode materials suitable for magnesium–lithium hybrid batteries are still limited, and developing the corresponding cathode materials is crucial for the development of magnesium–lithium hybrid batteries. In this study, a nanosheet-stacked NaTi2(PO4)3 nanocube material is synthesized via a hydrothermal method. Following carbon coating modification, this material is employed as a cathode, facilitating high-energy density storage in magnesium–lithium hybrid batteries. After 200 cycles at a current rate of 0.5 C, the battery maintains a discharge capacity of 79 mAh g–1 and delivers a specific capacity of 60 mAh g–1 at 2 C after 1300 cycles, corresponding to an 83% capacity retention. Mechanistic analysis of the battery confirms that Li+ undergoes de/intercalation exclusively at the cathode side, while Mg2+ experiences deposition and dissolution processes at the anode side.