High-performance electrochromic device based on poly acrylamide gel polymer electrolyte containing hypromellose

Abstract

Cellulose is one of the most widely distributed and abundant natural polymer material. Hypromellose (HPMC), a cellulose derivative, has received much attention in recent years in the field of electrolytes because of its biodegradability, high transparency, excellent water solubility and biocompatibility. In this work, poly acrylamide (PAM)-based hydrogel electrolytes with high ionic conductivity (5.3 × 10−2 S cm−1) and high transmittance (95.8% at 672 nm) were prepared by thermocuring AM monomer containing a certain amount of HPMC. We assembled an electrochromic device (ECD) based on this gel polymer electrolyte (GPE) with Prussian blue (PB) film and WO3·xH2O film. The ECD enables color switching between colorless and blue states. The optical modulation at 672 nm is 73.2% and the coloration efficiency is 154.7 cm2⋅C−1. The coloration time and bleaching time are 2.5 and 3.1 s, respectively. In addition, the optical modulation of the ECD remains 93.7% of its initial value after 1,000 cycles, demonstrating a good cycling stability of the ECD, which should be attributed to the existence of large number of hydrogen bonds between PAM and HPMC.