Bi-functional flexible electrodes based on tungsten trioxide/zinc oxide nanocomposites for electrochromic and energy storage applications

In this paper, the tungsten trioxide/zinc oxide (WO3/ZnO) nanocomposites were formed on flexible substrates by combining facile hydrothermal process and pulsed laser deposition (PLD) method. As bi-functional electrodes, the WO3/ZnO nanocomposites possess large specific surface area and a great number of micro channels, significantly increasing the area of WO3 active layer and facilitating the diffusion of Lim ions during the electrochemical process. Compared with dense WO3 film, WO3/ZnO nanocomposites exhibit enhanced electrochromic and capacitive performance of wider optical contrast (68.2%), greater coloration efficiency (80.6 cm(2)C(-1)) and higher areal capacitance (15.24 mF cm(-2)). Furthermore, based on the WO3/ZnO nanocomposites structure, a novel flexible electrochromicsupercapacitor was demonstrated, Which functions as a smart energy storage device able to visually monitor the level of stored energy by rapid and reversible color variation. The results present great potential of WO3/ZnO nanocomposites for electrochromic and energy storage applications. (C) 2017 Elsevier Ltd. All rights reserved.