Achieving Ultrahigh‐Rate and High‐Safety Li<sup>+</sup> Storage Based on Interconnected Tunnel Structure in Micro‐Size Niobium Tungsten Oxides
Yang Yang, He Zhu, Jinfei Xiao, Hongbo Geng, Yufei Zhang, Jinbao Zhao, Gen Li, Xun‐Li Wang, Cheng Chao Li, Qi Liu
Abstract
Abstract Developing advanced high‐rate electrode materials has been a crucial aspect for next‐generation lithium ion batteries (LIBs). A conventional nanoarchitecturing strategy is suggested to improve the rate performance of materials but inevitably brings about compromise in volumetric energy density, cost, safety, and so on. Here, micro‐size Nb 14 W 3 O 44 is synthesized as a durable high‐rate anode material based on a facile and scalable solution combustion method. Aberration‐corrected scanning transmission electron microscopy reveals the existence of open and interconnected tunnels in the highly crystalline Nb 14 W 3 O 44 , which ensures facile Li + diffusion even within micro‐size particles. In situ high‐energy synchrotron XRD and XANES combined with Raman spectroscopy and computational simulations clearly reveal a single‐phase solid‐solution reaction with reversible cationic redox process occurring in the NWO framework due to the low‐barrier Li + intercalation. Therefore, the micro‐size Nb 14 W 3 O 44 exhibits durable and ultrahigh rate capability, i.e., ≈130 mAh g −1 at 10 C, after 4000 cycles. Most importantly, the micro‐size Nb 14 W 3 O 44 anode proves its highest practical applicability by the fabrication of a full cell incorporating with a high‐safety LiFePO 4 cathode. Such a battery shows a long calendar life of over 1000 cycles and an enhanced thermal stability, which is superior than the current commercial anodes such as Li 4 Ti 5 O 12 .