Enhanced Electrochromic Performance of Film Based on Preyssler-Type Polyoxometalate and Tungsten Oxide

Abstract Tungsten oxide (WO 3 ) has received attention as an electrochromic material because of its excellent properties. However, the long switch time and low coloration efficiency of WO 3 film limit its use. Herein, a nanocomposite film containing Preyssler-type polyoxometalate (POM) K 12.5 Na 1.5 [NaP 5 W 30 O 110 ]·15H 2 O (P 5 W 30 ) and WO 3 nanoparticles has been fabricated by layer-by-layer (LbL) self-assembly methods and characterized by UV-Vis spectra, scanning electron microscopy, X-ray photoelectron spectroscopy and electrochemical workstation. Compared to the pure WO 3 film, the [P 5 W 30 /WO 3 ] 20 film has better electrochromic properties. Then, the electrochromic properties of [P 5 W 30 /WO 3 ] 20 film were studied in different electrolyte. The results indicated that the composite film show high coloration efficiency (191.62 cm 2 C − 1 ), fast switch time (2.58 s, 1.48 s), good CV stability (500 th) in 0.5 M LiClO 4 /PC electrolyte, and successfully assembled of an electrochromic device. These advantages can make the nanocomposite film become a promising candidate for potential application in electrochromic devices. Graphic Abstract