Electrochromic glass as a smart energy saving system

Electrochromic glass composed of ITO glass/WO3-x/ Li electrolyte/ NiO (or Prussian Blue)/ ITO glass has been proven to be the most efficient energy-saving system. The WO3-x film is a nanocrystalline form see Figure 1. The IR is the key component for housewarming. The electrochromic glass has two states: the clean and color states. As the Li+ ion is intercalated into the WO3-x film and leaves the Prussian blue film, both films turn out to be blue color (color state) and the IR reflectivity of both films increases to forbid IR from entering the room ( blue curve Fig. 2). As the Li+ ion was driven out the WO3-x and intercalated into the Prussian blue, the glass exhibited a clean state. In the clean state whole spectrum of the sunlight from ultraviolet to far-IR penetrates through the glass into the room (red curve). As shown in Figure 2. As the glass was switched to the color state (blue curve) the IR (including far IT and near IR) was reflected and forbidden to enter the room. The temperature outdoors is usually 85oC under the sun illumination, but the indoors is about 26oC in the color state, since the IR is not allowed to enter. The ability of heat isolation of electrochromic glass is comparable to reinforced concrete, and therefore, it is regarded as a “see-through” concrete which has great potential for applications in the outer curtain wall of buildings and sunroofs of automobiles. The electrochromic device can be controlled via a heat sensor and electric system; therefore it is usually referred as smart energy-saving technology, and it strongly fulfills the national policy of carbon neutralization and carbon peak.

We have already set up a mass production line for manufacturing large-size (1.2mx 1.8m) electrochromic glass. Fig. 3 is a picture of a large size (1.2m x1.8m) electrochromic window in clean (left) and color (right) states, respectively.