Enhanced lithiation dynamics in nanostructured Nb18W16O93 anodes

Abstract Lithium ion batteries are essential for energy storage in many applications, such as portable electronic devices and electric vehicles. However, charge-discharge rates and cycle life of the current batteries are insufficient to fulfill the targeted requirements of projected future devices, due to the severe limitations of conventional graphite anodes. Niobium tungsten oxides have recently been attracting attention as a new anode material for fast (dis)charging, owing to their stable host structure for lithium intercalation. It was originally believed that nanoscaling and nanostructuring would have a negligible effect on its electrochemical performance. However, the influence of the particle and grain size of niobium tungsten oxide electrodes on its electrochemical behavior is still an open question. This work reports on an investigation of the dependence of the lithiation process on the grain size of Nb18W16O93 anodes down to 60 nm. The results demonstrate that downscaling below 100 nm significantly enhances the lithiation dynamics of niobium tungsten oxide. Furthermore, it suggests that the grain boundaries of Nb18W16O93 have significant influence to the fast lithiation process. It provides a new perspective on the impact of downscaling grains to improve the electrochemical performance of Nb18W16O93 anodes for realizing fast (dis)charging in future energy storage devices.