Optimization of hydrogen-ion storage performance of tungsten trioxide nanowires by niobium doping

Abstract The transport and storage of ions within solid state structures is a fundamental limitation for fabricate more advanced electrochemical energy storage, memristor, and electrochromic devices. Crystallographic shear structure can be induced in the tungsten bronze structures composed of corner-sharing WO 6 octahedra by the addition of edge-sharing NbO 6 octahedra, which might provide more storage sites and more convenient transport channels for external ions such as hydrogen ions and alkali metal ions. Here, we show that Nb 2 O 5 ·15WO 3 nanowires (Nb/W = 0.008) with long length-diameter ratio, smooth surface, and uniform diameter have been successfully synthesized by a simple hydrothermal method. The Nb 2 O 5 ·15WO 3 nanowires do exhibit more advantages over h-WO 3 nanowires in electrochemical hydrogen ion storage such as smaller polarization, larger capacity (71 mAh g −1 , at 10C, 1C = 100 mA g −1 ), better cycle performance (remain at 99% of the initial capacity after 200 cycles at 100C) and faster H + ions diffusion kinetics. It might be the crystallographic shear structure induced by Nb doping that does result in the marked improvement in the hydrogen-ion storage performance of WO 3 . Therefore, complex niobium tungsten oxide nanowires might offer great promise for the next generation of electrochemical energy and information storage devices.