Coral-like Polyaniline/Barium Titanate Nanocomposite Electrode with Double Electric Polarization for Electrochromic Energy Storage Applications

When the electrochromic function is introduced into supercapacitors, the visible colour changes of supercapacitors can reveal their energy storage level, which prevents them from being overcharged. Here, a kind of solution-processable nanocomposite electrode material based on barium titanate (BT) and polyaniline (PANI) for high-performance electrochromic supercapacitors (ECSCs) was successfully prepared via in situ chemical oxidative polymerization. The obtained BT/PANI composites exhibited unique porous coral-like nanostructures, which facilitate the ion transport. In addition, we proposed a novel double electric polarization (DEP) model to account for the charge/ion transfer process of BT/PANI in the electric field, due to which the fabricated electrode exhibited ultra-high capacitance (340 F g−1 at 1 A g−1), durable cycling stability at high current density, and remarkable coulombic efficiency. Furthermore, the electrode possessed obvious electrochromic behaviours when it was charged or discharged at different current densities (the chromatic aberration value reached 42.9 at 1 A g−1). This bi-functional BT/PANI nanocomposite exhibits promising advantages for intelligent energy-storage devices.