Robust and swiftly multicolor Zn2+-electrochromic devices based on polyaniline cathode

Abstract

Multifunctional electrochromic (EC) devices are very important for the current research on smart electronic devices. Herein, we report a robust and swiftly multicolor EC energy storage device design based on polyaniline (PANI) cathode. To achieve this goal, we systematically studied the EC properties of PANI in aqueous and organic Zn 2+ electrolytes for the first time. Compared with Zn 2+ aqueous electrolyte, the PANI film measured in organic Zn 2+ electrolyte delivered a fast-switching time (τ c /τ b = 2.0/2.4 s), high optical contrast (72.2%), high coloration efficiency (205 cm C −1 ), and good cycle stability (optical contrast remains 92.7% after 10,000 cycles). The excellent EC performance could be attributed to the good wettability of the interface between organic Zn 2+ electrolyte and PANI film, which supports rapid charge transfer kinetics. The PANI cathode in the organic Zn 2+ electrolyte also provided a multicolor electrochromism (light yellow, green and dark green) along with a high specific capacitance of 26.4 mAh m −2 and 72.2% spectral modulation range at a current density of 0.1 A m −2 , excellent rate capability of 86.4% capacity retention and 81.3% spectral modulation even at an 8-fold current-density increase. The laboratory prototype device also verified the EC energy storage performance of organic Zn 2+ intercalated/deintercalated PANI, confirming that they are suitable for highly robust multicolor EC energy storage applications. • The EC properties of PANI film in aqueous and organic Zn 2+ electrolytes for the first time were systematically revealed. • The PANI film delivered a fast-switching time, high optical contrast, high coloration efficiency, and excellent cycle stability (optical contrast remains 92.7% after 10,000 cycles). • The laboratory prototype device based on PANI showed a good EC performance as well as energy storage.