Porous alpha-MoO3/MWCNT Nanocomposite Synthesized via a Surfactant-Assisted Solvothermal Route as a Lithium-Ion-Battery High-Capacity Anode Material with Excellent Rate Capability and Cyclability

摘要

A high-performance alpha-MoO3/multiwalled carbon nanotube (MWCNT) nanocomposite material is synthesized via a novel surfactant-assisted solvothermal process followed by low-temperature calcination. Its structure, composition, and morphology are characterized by X-ray diffraction, X-ray photoelectron spectroscopy, energy-dispersive X-ray spectroscopy, carbon element analysis, nitrogen adsorption-desorption determination, scanning electron microscopy, and transmission electron microscopy techniques. Its electrochemical performance as a high-capacity lithium-ion-battery anode material is investigated by cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic discharge/recharge methods. This composite material exhibits not only high capacity but also excellent rate capability and cyclability. For example, when the discharge/charge current density is increased from 0.1 to 2 A g(-1), the reversible charge capacity is only decreased from 1138.3 to 941.4 mAh g(-1), giving a capacity retention of 82.7%. Even if it is cycled at a high current density of 2,0 A g(-1), a reversible charge capacity of 490.2 mAh g(-1) is still retained, showing a capacity retention of 43.1%. When it is repeatedly cycled at a current of 0.5 A g(-1), the initial reversible charge capacity is 1041.1 mAh g(-1). A maximum charge capacity of 1392.2 mAh g(-1) is achieved at the 292th cycle. After 300 cycles, a high charge capacity of 1350.3 mAh g-1 is maintained. Enhancement of the electrical conduction contributed by the MWCNT composite component as well as the loose and porous texture of the MoO3/MWCNT composite is suggested to be responsible for the excellent performance.