Control Growth of Mesoporous Nickel Tungstate Nanofiber and Its Application as Anode Material for Lithium-Ion Batteries

Achieving a control over the growth of one-dimensional nanomaterial is significant for the study of energy storage material and device. In the present work, nickel tungstate (NiWO4) nanofiber was synthesized by electrospinning technique combined with subsequent annealing treatment. The obtained NiWO4 nanofiber is found to be highly crystalline and possesses a diameter of about 180 nm and a length of several millimeters. The influence of severe-annealing treatment on the structure and the electrochemical performance is studied and found that the temperature of annealing is a crucial factor in the crystalline phase, purity, structure and morphology. The impurities in the product of electrospinning disappeared, when the annealing temperature is raised from 650 to 670 °C, and a pure phase of mesoporous NiWO4 nanofiber is obtained. However, for the temperature raising from 670 to 700 °C, the crystalline grains of the nanofiber grew and merged rapidly, as the mesoporous structure is disappeared. The lithium-ion battery furnished by the NiWO4 nanofiber annealed at 700 °C as anode material, shows a moderate performance, while the battery provided by NiWO4 nanofiber annealed at 670 °C exhibits an excellent lithium storage performance with high initial coulombic efficiency, high specific capacity, good cycle performance and rate performance. The initial coulombic efficiency could reach as high as 77.1%. A high reversible capacity of 514 mAh g−1 at a current density of 100 mA g−1 is achieved after 100 charge/discharge cycles, which indicated that NiWO4 nanofiber was a promising candidate anode material for lithium ion battery.