Study on Two Inorganic Consumables in PMMA Electrochromic Devices Based on Work Function Differences

In electrochromic devices, the dielectric layer is not only an electrode dielectric, but also can provide compensating ions for electrochromism. In this paper, three composite porous materials, PMMA/SiO2, PMMA/TiO2, and PMMA/SiO2/TiO2, were prepared and assembled using polymethyl cellulose (PMMA) as the polymer matrix, impurity medium (SiO2) and titanium dioxide (TiO2) inorganic polymers, and the effect of doping two inorganic porous materials on the electrochromic performance was studied. The optical recovery and cycle stability of electrochromic wear of the PMMA/SiO2/TiO2 composite structure are significantly improved compared with the loss of other ceramic structures. Cyclic voltammetry analysis shows that the lithium ion diffusion coefficient of the electrochromic device using the PMMA/SiO2/TiO2 composite ceramic structure is the largest, which is 2.5 × 10−14 cm2​ s−1 . The improvement of electrochromic performance is mainly due to the difference in work function between SiO2 and TiO2 on the figure of merit diagram, which leads to the directional movement of the resonator, accelerates the transmission rate of Li+ and further optimizes the electrochemical properties of the composite ceramic. This study provides an effective method to improve the performance of electrochromic devices.