A Wide‐Temperature Adaptive Electrochromic Device Based on a Poly(vinyl alcohol)/Poly(acrylic acid) Gel Electrolyte

Abstract As a promising energy‐saving technology, electrochromic technology has been widely investigated for practical applications. However, there is relatively few research about the applications under certain extreme climatic conditions since gel electrolytes often occur freezing and volatilizing. In this work, a poly(vinyl alcohol)/poly(acrylic acid) (PVA/PAA) gel electrolyte with good anti‐freezing and heat‐resistance performance is developed. Utilizing hydrated tungsten oxide (WO 3 · x H 2 O) and polyaniline (PANI) as electrochromic materials and the PVA/PAA gel as electrolyte, a WO 3 · x H 2 O/PVA/PAA‐ethylene glycol (EG)‐H 2 O/PANI electrochromic device (WO 3 · x H 2 O/PAEH/PANI ECD) is obtained, which can work efficiently at wide operating temperatures from −20 to 60 °C. The device has multiple reversible color changes, a large optical modulation of 66.2% at 600 nm, high coloration efficiency of 386.0 cm 2 C −1 , fast responses (with coloration/bleaching times of 1.3/1.1 s), as well as excellent cyclic stability (82.0% of the initial optical modulation is still retained after 2100 cycles). This work reveals the potential application prospects of PAEH gel electrolyte in practical extreme operating conditions.