Controlled synthesis of 3D urchinlike niobium tungsten oxide nanostructure for fast hydrogen ion storage

Abstract The shear crystal structure through metal doping can effectively promote the transport speed of ions and electrons in metal oxides, which has important dynamic significance for the design of high-performance energy storage materials. Herein, a 3D urchinlike niobium tungsten oxide (NWO) nanostructure as an efficient hydrogen ion storage material is reported for the first time, which exhibits a capacity of 88mAh g −1 at 20 °C (1 °C = 100 mA g −1 ). The large specific capacity of the 3D urchinlike NWO nanostructure is ascribed to the reversible reaction of a great quantity of W 6+ , W 5+ and W 4+ in the process of protonation and deprotonation processes. In addition, hydrogen ions can still be stored in large and stable quantities, even at rates as high as 100 °C (75 mAh g −1 at 100 °C). The improvement of hydrogen ion storage properties is arising from an optimized morphology of niobium tungsten oxide via tuning of the crystal structure. The high specific superficial area 3D urchinlike shape with rich one-dimensional nanostructures significantly shortens charge-carrier transport distances, ensuring rapid interfacial electronics movement to polish up ion storage kinetics. Consequently, this crystallographic shear structure strategy to boost hydrogen ion storage capacity may be universal and is likely to pave the way toward highly capacity hydrogen ion energy storage systems.