The world is currently facing the crises of global warming and energy shortages, and energy-saving products can significantly reduce energy consumption. Electrochromic devices (ECDs) are an active dimming technology that controls temperature in vehicles and indoor environments by blocking infrared light, thus reducing vehicle fuel consumption and the energy used for heating and cooling in office buildings and homes. Additionally, ECDs have applications in antiglare automobile rearview mirrors, various displays, optical shutters, optical recording, and image storage.
A typical ECD structure includes five functional layers encased between two transparent substrates: a transparent conductive layer, an electrochromic layer, an electrolyte layer, an ion storage layer, and another transparent conductive layer, as shown in Figure 1. National Atomic Research Institute (NARI) is dedicated to developing energy-saving technologies. In addition to advancing electrochromic glass technology, NARI has recently developed a flexible ion storage layer using plasma coating technology on a flexible conductive substrate (ITO-PET). This development, combined with the gel electrolyte technology from partner companies, has led to the successful creation of flexible electrochromic devices. These devices can be applied to various materials and can change color on curved surfaces, such as in sunglasses and snow goggles, as shown in Figure 2.
Currently, by integrating NARI’s developed gel polymer electrolyte (GPE) lithium ion battery technology, flexible electrochromic products have been manufactured, as shown in Figure 3. The specifications of the GPE membrane are detailed in Table 1. The GPE membrane is flexible and compatible with flexible electrochromic device applications, eliminating the need for additional circuitry. The electrochromic device has successfully undergone 20,000 color change cycles in product lifespan testing, as shown in Figure 4, demonstrating its commercial potential.