Tungsten-copper (W-Cu) composite materials have comprehensive properties such as good thermal conductivity, electrical conductivity, low thermal expansion, non-magnetic, good performance under vacuum, and arc corrosion resistance, and are widely used in civil industry and aerospace fields. Therefore, they are often used as electrical contacts, especially in high voltage applications.

With the development of industrialization, nitrogen dioxide (NO2) in automobile exhaust and industrial emissions is a serious threat to human health and the ecological environment. 0.1 ppm or even less NO2 will cause significant health effect to human health. Therefore, the highly sensitive NO2 gas sensor has attracted widespread attention. In various gas sensors, metal oxide semiconductor-based sensors are widely applied in industrial, medical and other fields. Due to the presence of several oxidation states of W, tungsten oxide (WO3) is a common sensing material for NO2 semiconductor sensors.

In the past few decades, electrochromic devices have received great attention from researchers in related fields in the materials industry. Electrochromism is a reversible change in optical properties (such as absorbance and transmittance) of a material under low electric fields. Electrochromic devices have a wide range of applications, including reflective displays, smart windows, information displays, and electrochromic paper.