Nano‐Sized Niobium Tungsten Oxide Anode for Advanced Fast‐Charge Lithium‐Ion Batteries

Abstract The further demand for electric vehicles and smart grids prompts that the comprehensive function of lithium‐ion batteries (LIBs) has been improved greatly. However, due to sluggish Li+ diffusion rate, thermal runway and volume expansion, the commercial graphite as an important part of LIBs is not suitable for fast‐charging. Herein, nano‐sized Nb14W3O44 blocks are effectively synthesized as a fast‐charge anode material. The nano‐sized structure provides shorter Li+ diffusion pathway in the solid phase than micro‐sized materials by several orders of magnitude, corresponding to accelerating the Li+ diffusion rate, which is beneficial for fast‐charge characteristics. Consequently, Nb14W3O44 displays excellent long‐term cycling life (135 mAh g‐1 over 1000 cycles at 10 C) and rate capability at ultra‐high current density (≈103.9 mAh g‐1, 100 C) in half‐cells. In situ X‐ray diffraction and Raman combined with scanning electron microscopy clearly confirms the stability of crystal and microstructure. Furthermore, the fabricated Nb14W3O44||LiFePO4 full cells exhibit a remarkable power density and demonstrate a reversible specific capacity. The pouch cell delivers long cycling life (the capacity retention is as high as 96.6% at 10 C after 5000 cycles) and high‐safety performance. Therefore, nano‐sized Nb14W3O44 could be recognized as a promising fast‐charge anode toward next‐generation practical LIBs.