Low-power, fast response simplified electrochromic device based on functionalized gel electrolyte

Metallo-supramolecular polymer (MEPE)-based thin film electrochromic devices (ECDs) have been considered to be a promising platform for portable electronics as their low cost, excellent redox properties, high optical contrast, and rich colors. However, poor cycle stability and slow response speed are serious bottlenecks for widespread commercial devices. Here, a gel electrolyte functionalized by the anodic active species p-benzoquinone (p-BQ) (GET-BQ) was reported. It has outstanding conductivity (∼4.62 mS cm−1) and transparency. Fe(Ⅱ)-MEPE-based ECDs incorporating the GET-BQ electrolyte (ECD-BQ) showed lower voltage operation (∼1.1 V), higher optical contrast (ca. ΔT ∼ 35.7%), faster response rate (tb ∼ 2.5 s, tc ∼ 0.3 s), and superb cycling durability (<1.7% ΔT loss after 1440 cycles) than those without p-BQ. Moreover, the charge transport kinetics of ECD-BQ were explored by the CV curve, in situ infrared spectroelectrochemical analysis, and electrochemical impedance spectroscopy. The charge transfer mechanism of electrochromic material and electrolytes in ECD-BQ offers a novel entry to design superior electrolytes for high-performance ECD.