Dual-functional electrochromic and energy-storage electrodes based on tungsten trioxide nanostructures

Abstract

In this paper, high-performance dual-functional electrodes based on tungsten trioxide (WO3) nanostructures are developed, which successfully realize the combination of electrochromism and energy storage. The WO3 nanostructures with various morphologies (nanospindles, nanopetals, nanosheets, and nanobricks) were prepared via a facile hydrothermal process. It has been found that the WO3 nanosheets possess large surface area and porous architecture, significantly increasing the amount of active sites and facilitating the transport of Li+ ions. As dual-functional electrode, WO3 nanosheets present enhanced electrochemical properties including wide optical modulation (64.5%), fast switching time (6.6/3.8 s), great coloration efficiency (48.9 cm2 C−1), and high areal capacitance (14.9 mF cm−2). Furthermore, the WO3 nanosheets could bridge electrochromic behaviors with energy storage by changing color during the charge/discharge processes. The results demonstrate great potential of WO3 nanosheets for electrochromism and energy storage applications.