Polyaniline films with modified nanostructure for bifunctional flexible multicolor electrochromic and supercapacitor applications

The flexible polyaniline (PANI) thin films with modified nanostructure are prepared on flexible indium tin oxide (ITO)/polyethylene terephthalate (PET) substrates by combination of galvanostatic and cyclic voltammetric electrodeposition techniques. The electrochemical properties of as-prepared PANI nanomaterials are investigated by using the PANI film as an active material of the electrode for primary electrochromic device and electrochemical supercapacitor. This film presents a remarkable mechanical flexibility, high coloration efficiency of 80.9 cm2 C−1 at 630 nm and noticeable multicolor performances with reversible color change of transparent, pale yellow, green, blue and blue-purple. Further, a smart supercapacitor is presented, and the level of energy storage can be monitored by the change of optical performance. The film displays the highest specific capacitance of 473.3 F g−1 at the scan rate of 0.03 V s−1. The high-performance PNAI film exhibits promising features for various emerging flexible and multicolor electronics and optoelectronic devices combining energy storage and electrochromism.