Highly efficient dark to transparent electrochromic electrode with charge storing ability based on polyaniline and functionalized nickel oxide composite linked through a binding agent

Abstract

Here in this work, a black to transparent efficient electrochromic electrode based on nickel oxide (NiO) functionalized polyaniline (PANI) composite has been prepared. To ensure strong interaction among NiO and PANI, NiO nanoparticles were first functionalized with (3-Aminopropyl) trimethoxysilane (3-APTS) followed by subsequent attachment to monomer. This linking agent 3-APTS makes a bridge between NiO and PANI. Prepared PANI-fNiO composite exhibits extended contrast throughout the visible spectrum as well as in near-IR and near-UV regions with superior coloration efficiency of 138 cm2C-1. The composite PANI-fNiO was found to have improved cyclic stability of 7000 cycles. Thus with such kind of attachment both components synergistically favor each other’s coloration and bleaching, rendering dark (almost) black to transparent electrochromism. Observed hexagonal nanoparticles with ion diffusion channels were observed to give a fast response of 1.5s/2s for coloration and bleaching respectively. Moreover, PANI-fNiO shows pseudocapacitive behaviour with a large areal capacitance of 1.1 F cm−2. Both electronic and ionic charge transport mechanisms in such bonded PANI-fNiO composite have been studied using temperature dependent dc conductivity studies, cyclic voltammetery and electrochemical impedance spectroscopy. The observed results present the strong potential of PANI-fNiO composite as an integrated electrochromic electrode with charge storing ability.