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

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 Nb14 W3 O44 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, Nb14 W3 O44 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 Nb14 W3 O44 ||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 Nb14 W3 O44 could be recognized as a promising fast-charge anode toward next-generation practical LIBs.