Embedded Double One-Dimensional Composites of WO₃@N-Doped Carbon Nanofibers for Superior and Stabilized Lithium Storage

Tungsten oxide has received plenty of attention as a potential anode material for lithium-ion batteries (LIBs) due to the high intrinsic density and abundant framework diversity. However, the tremendous structural and volumetric changes of tungsten oxide (WO₃) restrict the commercial application. A novel embedded one-dimensional (1D) structure composite of the WO₃ and N-doped carbon nanofibers (WO₃@N-CNFs) has been prepared by combining convenient hydrothermal and electrospinning processes. The WO₃ nanowires are firmly wrapped in the N-CNFs and formed an embedded double 1D structure, which can significantly improve the structure stability of the composite. Therefore, the WO₃@N-CNFs delivers a high specific capacity of 960 mAh/g after 300 cycles at 0.2 A/g, and 550 mAh/g after 1300 cycles at 2 A/g. Moreover, the initial Coulomb efficiency of WO₃@N-CNFs is enhanced to more than 80 %. The electrochemical performance is better than those from most WO₃-based carbon composite materials, which can be ascribed to the synergy effects of the WO₃ nanorods and the nitrogen doping in 1D carbon nanofibers. As a consequence, the WO₃@N-CNFs can be a promising anode material with the extraordinary long-term cycling performance at high current densities, and provide a new idea for the commercialization of WO₃-based carbon composite materials.