Organic Electronics for Electrochromic Materials and Devices. Hong Meng
have been developed, ranging from traditional metal oxides to more recent organic polymers, small molecules, and hybrid materials. Moreover, benefit from the ECD design and structural optimization, flexible substrate‐based devices were fabricated with the low‐price roll‐to‐roll process, which makes the EC technology have large scope applications, such as smart windows for reducing building energy consumption, self‐powered EC window using organic photovoltaic cells as power supplement, car rear‐view mirrors for greater safety, and smart sunglasses for better UV‐radiation protection. Many of these technologies and applications have been commercialized and are available on the market. With the concerted efforts of researchers and engineers, we believe that the new EC materials and advanced technologies will constantly develop and more advanced ECD with low manufacturing cost will be exploited to realize practical applications.
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2 Advances in Polymer Electrolytes for Electrochromic Applications
2.1 Introduction
The ionic conduction medium between the electrodes and electrochromic (EC) materials is an electrolyte, which is one of the most essential active components in electrochromic device (ECD). Electrolyte provides an indispensable role as the prime ionic conduction medium between the electrodes while preventing electron conduction between the two electrodes during EC operation. The important electrolyte properties greatly affecting the EC performance are the electrolyte ionic conductivity, ion dissociation, transport rate of ion through bulk and interface, and thermal stability [1]. Electrolytes were initially reported in the early 1970s, including ceramic, glass, crystalline, and polymer electrolytes (PEs). PE was first introduced by Fenton et al. in 1973 [2] and widely applied since 1980s [3]. In the past decades, PEs attracted much attention from all over the world's researchers due to their promising applications in electrochemical storage/conversion devices.
In general, electrolytes can be classified into PEs, liquid electrolytes, ceramic electrolytes, and solid inorganic electrolytes [4–6]. Briefly, PE is a membrane composed of a dissolution of salts in a polymer matrix with high molecular weight [7]. PE is widely applied in electrochemical devices such as solid‐state batteries and rechargeable batteries, ECDs, supercapacitors, fuel cells, dye‐sensitized solar cells, and EC windows. Technologically, PEs evolved from polymer, liquid ionic conductor and solid‐state