Metal oxide-mixed polymer-based hybrid electrochromic supercapacitor: improved efficiency and dual band switching

The inclusion of charge storage properties in electrochromic devices (ECDs) has gained much interest and has evolved into a promising emerging energy-related field due to multifunctional smart device applications. Here, an organic-inorganic solid-state asymmetric electrochromic supercapacitor device (ESCD) containing nano-CoTiO3-mixed poly-3-hexylthiophene and WO3 as two electrodes has been designed to study electrochromic and supercapacitor properties. The electrochemical properties of CoTiO3 show a pseudocapacitive-type charge storage capability, which has been utilized to enhance the electrochromic performance of the ESCD with additional charge storage ability. The device shows charge storage properties with fast charging and slow discharging, giving very high coulombic efficiency with a specific capacitance of 6.4 mF cm-2 at 0.2 mA cm-2 current density. The device shows excellent electrochromic supercapacitive properties with a color contrast of similar to 50% and a short switching time of similar to 1 s at a 515 nm wavelength with excellent cyclic stability. The device exhibits the capability to cut near infrared wavelength (700 nm and 850 nm) and has a potential application as a heat filtering device. Thus, the addition of pseudocapacitive-type materials in ECDs enhances the capacitive performance along with electrochromic properties, which makes ECDs more suitable for real life applications.