Ultra-low-cost, flexible and durable electrochromic tape device based on aluminum foil

Abstract

Electrochromic devices (ECDs) have the ability to selectively change their color state. They come in many forms, such as smart windows, e-ink displays and recently even as flexible tapes. Since most of ECDs incorporate traditional “sandwich” architecture, which requires at least one electrode to be made of a transparent conductive polymer or thin film ceramics, they are considered too expensive and fragile compared to devices made from metal or alloy foils. For the first time, we present a true low-cost, flexible and durable ECD tape that uses a common “kitchen-grade” aluminum foil for electrodes, while employing a Li-WO3 intercalation based electrochromic system. The presented ECD tape is capable of showing two color states. The tested tapes were up to 20 cm long but could be easily made longer due to their “inverted sandwich” architecture. Due to the absence of transparent counter electrode, the assembled ECD tape has excellent durability properties and could be used in color changing clothes, adaptive camouflage or other applications.