Nano Aerogel-Based VIS-NIR Switchable Electrochromic Supercapacitor: Energy Storage and Heat-Shielding Device

Power-efficient electrochromic devices that can exhibit multifunctional applications, especially in the areas of energy storage and savings, are increasingly in demand. Here, an inorganic–organic electrochromic smart window has been designed in which a self-supporting aerogel-type network of tin-doped indium oxide (a-ITO) nanoparticles was doped to enable applications in supercapacitive energy storage. The devices based on poly(3-hexylthiophene-2,5-diyl) (doped with incorporated a-ITO) and viologen exhibit bias-induced color modulation in the visible and infrared range. This function can be employed to prevent the transmission of latter radiation to maintain a temperature difference on the two sides of the device when it is turned ON with a bias voltage of 1.6 V. The device exhibits an electrochromic supercapacitor property with a maximum coloration efficiency of 966 cm 2 /C with a switching time of only 0.5 s, color contrast of 61%, and high specific capacitance of 17 F/g. Potential applications of the device in temperature shielding are discussed, and a maximum cooling efficiency of 32% is demonstrated. Overall, a recipe is developed to design energy-storing and energy-saving multicolor-switchable smart windows for application in designing energy-efficient smart windows/buildings.