An electrochromic and self-healing multi-functional supercapacitor based on PANI/nw-WO_2.7/Au NPs electrode and hydrogel electrolyte

Supercapacitors with various functions have been attracting continuous interest due to their key role in modern electronics. In addition to flexibility and transparency, researches also focus on the electrochromism of supercapacitors, which can be used to indicate the remaining capacity of the devices. The self-healing supercapacitors can also recover their energy-storage performances automatically after mechanical damage, thus exhibiting excellent reliability and maintenance. Herein, we report a facile strategy to fabricate a flexible supercapacitor with both electrochromic and self-healing properties. In this design, the classical color-changing materials: polyaniline (PANI) and tungsten oxide nanowires (WO_2.7 NWs) are used together to enlarge the electrochemical window, and give the electrode material electrochromic properties. And then Au nanoparticles (Au NPs) are sprayed onto the surface to further increase the electrochemical conductivity. Besides, a novel self-healing hydrogel is synthesized to be used as solid electrolyte. Finally, a symmetrical supercapacitor device is assembled, which shows the areal capacitance of 61 mF/cm² with excellent stability. By this design, we firstly fabricate a supercapacitor with many functionalities, such as, flexibility, transparence, color changing and self-healing properties all together, providing a new integration strategy for satisfying the next-generation electronics.