A flexible, electrochromic, rechargeable Zn-ion battery based on actiniae-like self-doped polyaniline cathode

Abstract

Flexible/wearable electrochromic zinc-ion battery (EC-ZIB) is considered to be promising smart multifunctional energy storage devices that monitor energy storage on the basis of their color variation. Herein, a self-doped PANI (SPANI) electrode has been prepared by a facile electrochemical copolymerization process. The prepared SPANI film exhibits a novel actiniae-like morphology, which is beneficial for electrolyte infiltration due to short ion diffusion pathways and fast electrochemical kinetics that ensure enhanced specific capacity. In a full all-in-one EC-ZIB device, the SPANI cathode provides a high specific capacitance of 180.5 mA h g⁻¹ at 0.5 A g⁻¹, excellent rate capability of 75.3% capacity retention even at a 20-fold current-density increase. The EC-ZIB possesses high energy and power densities (181.1 W h kg⁻¹ @ 501.8 W kg⁻¹ and 124.7 W h kg⁻¹ @ 9148.6 W kg⁻¹). At the same time, another positive is that the EC-ZIB has excellent electrochromic properties (light yellow, green and dark green) from 0.5 to 1.6 V. Therefore, its energy storage can be conveniently monitored according to color variation. The EC-ZIB efficiently combines multiple smart features, promoting the development of flexible intelligent energy storage devices.