Tungsten trioxide is a chemical compound consisting of oxygen and
the transition metal tungsten. It occurs naturally but rarely in the
form of hydrates in some kinds of minerals. It has various
applications. In industry, it can be used for making x-ray screen
phosphors, fireproofing fabrics and gas sensors as well as a pigment
in ceramics and paints. It can also be used for the preparation of
electrochromic windows or smart windows. In addition, it can be used
in semiconductors. It, together with titanium dioxide, has the
potential to become an efficient photo-catalyst under visible light
irradiation. Recent study has shown that mesoporous tungsten
trioxide polyaniline nanocomposite can be used as an anode material
for high-performance lithium-ion batteries.