Molybdenum Phosphide: A Conversion-type Anode for Ultralong-Life Sodium-Ion Batteries

Abstract

High specific capacity and long cycling life of anode materials still remain major challenges in the development of sodium-ion batteries (SIBs). Nowadays, transition metal phosphides have been reckoned as promising anodes in view of their high theoretical specific capacities, low potential for sodium storage, and superior conductivity. Herein, molybdenum phosphide (MoP) nanorods wrapped with thin carbon layer have been prepared and applied as an anode for SIBs. By utilizing in situ X-ray diffraction technology, a conversion-type mechanism of MoP anode has been disclosed. This kind of MoP electrode exhibits extraordinary electrochemical properties, including excellent cycling performance with a discharge capacity of 398.4 mA h g–1 at a current density of 100 mA g–1 after 800 cycles, and remarkable rate capabilities, which remain 104.5 mA g–1 at 1600 mA h g–1 even after 10 000 loops. The distinguished performances stem from synergetic merits of the morphology, structure, and mechanism of MoP. It is expected that MoP will be a promising anode material for SIBs and this work would provide theoretical basis for the scalable research and applications of MoP-based anode materials for SIBs.