Tungsten bronze is a non-stoichiometric compound and its formula is generally expressed as M_xWO₃ (0 <x <1). The value of x can vary within a certain range and there is no specific stoichiometric ratio between the components, so it is called non-stoichiometry compound, wherein M can be calcium, strontium, barium, rare earth metals, copper, silver, etc., of which tungsten may also be substituted with niobium, tantalum, titanium and other metals for generating other bronzes, this compounds having special physical and chemical properties, in addition to bright metallic luster, but also has high electronic conductivity and fast ion transport properties, are new types of electrode material used in lithium battery cathode materials, sensors and ion secondary battery.

 

Tungsten oxide is a widely-studied transition metal oxide. Because of its special properties, it’s expected to be applied in electrochromic devices, sensors, separation material, etc., which has been widespread concern. In recent years, the preparation of nanoparticles has made significant progress. At present, the focus of the study has shifted to anisotropic nanoparticles, since the anisotropic nanoparticles can be arranged and functional according to the needs, especially in one-dimensional transition metal oxide nano-materials with special optical and magnetic and electronic properties, which has caught more and more people's attention. And the transition metal ions get into the material skeleton structure, changing the microstructure or surface properties of the material to make its performance better, that is the hot spot of material modification. W ions in tungsten bronze tungsten oxide have variable valence, valence of W changes when the transition metal is introduced into the crystal structure. In the mutual conversion process of W⁶⁺, W⁵⁺ and W⁴⁺, there will be the formation of unstable oxygen vacancies in crystal lattice, surface defects and so on, which will lead to that the tungsten oxide exhibits specific physical and chemical properties, and it must have important uses.