Therefore it is necessary to synthesize a new type

In the present work, a convenient strategy was put forward to synthesize a new type of WO3-TiO2 thin film as the electrode material of the electrochromic device. The composite film with core/shell structure was firstly prepared by hydrothermal and sol-gel method. The improved electrochromic properties of the TiO2/WO3 core/shell nanoarrays film are obtained mainly due to the high surface area, good contact with the electrolyte solution and fewer defects, leading to faster Li1+ Pam3CSK4 rate and better electrochemical cycling stability. The new structure of TiO2/WO3, producing the best possible advantage of WO3 and TiO2, can be regarded as an ideal electrochromic material with high practical value.
2. Experiment
2.1. Synthesis of TiO2 nanoarrays
2.2. Synthesis of WO3 precursor solution
WO3 precursor was prepared by dissolution of 12 g of W metal powder in 84 ml of H2O2 (30%). Being exothermic, the reaction was conducted between 0 and 10 °C and then magnetic stirred for 3 hours. The resulting pale yellow turbidity solution was centrifuged at 3, 000 rpm for 5 minutes to obtain a parasitism pale yellow solid after solid-liquid separation. The clear and bright solution obtained was placed in dry oven at 60 °C to remove the excess hydrogen peroxide completely. Then add a certain amount of ethanol to obtain the WO3 precursor solution ultimately.