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

Abstract 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 (WO 3 ) restrict the commercial application. A novel embedded one‐dimensional (1D) structure composite of the WO 3 and N‐doped carbon nanofibers (WO 3 @N‐CNFs) has been prepared by combining convenient hydrothermal and electrospinning processes. The WO 3 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 WO 3 @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 WO 3 @N‐CNFs is enhanced to more than 80 %. The electrochemical performance is better than those from most WO 3 ‐based carbon composite materials, which can be ascribed to the synergy effects of the WO 3 nanorods and the nitrogen doping in 1D carbon nanofibers. As a consequence, the WO 3 @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 WO 3 ‐based carbon composite materials.