High performance PANI/MnO2 coral-like nanocomposite anode for flexible and robust electrochromic energy storage device

The conductive polymer polyaniline (PANI) has attracted much attention in the field of electrochromic energy storage device (EESD) due to its rich color changes and good pseudocapacitive properties, however, the operating voltage window and cycling stability of PANI material, as an essential part in the full electrochromic devices, has failed to be fully explored and employed. Herein, we synthesized the PANI and MnO2 nanocomposite structure via robust one-step electrodeposition approach, forming an intriguing architecture similar to the coral-like nano-porous. The rougher coral-like structure provides a great quantity nano porous ion transport channel, which greatly improves the working voltage range and cycling stability of the electrode, and shows great potential as an anode electrode for EESDs. In addition, we built a complementary full EESD prepared with tungsten oxide (WO3) as the counter electrode, which has both electrochromic and energy storage dual function integration, allowing real-time observation of the EESD operating state based on color change. It can work stably under a large voltage window of -2V–1.5V, with good bistable performance, fast response speed and more than 1000 times electrochemical cycle life. This work provides a new opportunity to design next-generation high-performance and intelligent hybrid energy storage system for consumer electronics.