Preparation and property characterisation of high cycle TiO₂/PANI electrochromic thin films

Given the extensive prospective applications of electrochromic thin films in fields such as military camouflage, building energy efficiency, and the automotive industry, this study was conducted to prepare TiO₂/Polyaniline (PANI) composites via a chemical oxidation method. The prepared TiO₂/PANI electrodes and PANI electrodes were tested and analysed using XRD, FTIR, SEM, XPS, TG, UV-vis and electrochemical workstations. The focus was on the study of the structural morphology, electrochemical properties, and the mechanism of the changes in the electrochromic properties of TiO₂/PANI composite films and PANI films. The results demonstrate that the TiO₂/PANI composite film exhibits a donor-acceptor structure with a greater number of active sites compared to that of the PANI film, which has a fibrous structure; the structure of TiO₂/PANI composite films accelerates the transformation process of PANI protonation and deprotonation, improves the charge transfer pathway, shortens the ion diffusion pathway, and slows down the oxidative degradation of PANI in the process of electrochromic change; the structure of TiO₂/PANI composite films is better than PANI films in the process of electrochromic change. The electrochromic performance of the composite film was enhanced in comparison to that of the PANI film, with a colouring efficiency (CE) at wavelength 650 nm of 48.52 cm²·C⁻¹. Additionally, the fading and colouring response times were 2.5 and 3 seconds, respectively. The electrochemical activity of the film was maintained at approximately 71.1% of the initial value after 800 cycles of colouring and fading.