Bifunctional electrochromic-energy storage materials with enhanced performance obtained by hybridizing TiO2 nanowires with POMs

Multifunctional electrode materials have been widely studied in recent years, owing to their various excellent performance. Herein, we report a nanocomposite film based on Dawson-type monolacunary polyoxotungtate K10P2W17O61 and TiO2 nanowires fabricated via hydrothermal and Layer-by-Layer self-assembly combination methods, in which successfully realized the bifunctional combination of electrochromism energy storage. Compared to individual K10P2W17O61 thin film, the nanocomposite film showed outstanding electrochromic properties of high coloration efficiency (150.34 cm2/C at 600nm) and cyclic stability, and the volumetric capacitance of composite film reaches 172.3 F cm−3 with working voltage window of 1.77V. The greater electrochemical properties could due to the unique 3D structure of the TiO2 NW arrays which provides a larger electrolyte contact area and shorter ion diffusion pathway available for the redox reactions. Our study provides a new route to design bifunctional electrode material with enhanced electrochromism and energy storage functions, making polyoxometalate-based electrode materials more attractive for practical applications.