Enhanced electrochromic properties of a TiO2 nanowire array via decoration with anatase nanoparticles

Construction of a micro-/nanostructured TiO2 film has been considered to be an important way to enhance the electrochemical properties and electrochromic performance of the material. Herein, we investigated the electrochromic properties of a nanocomposite TiO2 film prepared by decorating rutile a TiO2 nanowire (TiO2 NW) array with anatase TiO2 nanoparticles (TiO2 NPs) via a facile two-step synthesis method. Owing to its large active surface area and high transparency, the TiO2 NW-NP composite film supported a greater number of sites for Li+ ion intercalation and extraction. As a result, the TiO2 NW-NP film displayed higher optical contrast, coloration efficiency and transient current density compared with NW and NP films, demonstrating that enhanced electrochromic properties could be achieved using the NW-NP composite structure.