A monolithic integrated ultra-flexible all-solid-state supercapacitor based on a polyaniline conducting polymer

Abstract

This work presents a monolithic integrated supercapacitor (SC), where all the SC components, including current collectors, electrodes and solid-state electrolyte, are arranged in a porous thin support, thus resulting in a significant reduction in the device volume and good interface between each component. Due to the stress-compensation effect, this monolithic integrated configuration can also effectively improve the polyaniline (PANI) morphologies with good uniformity and a well-defined porous nanostructure. Compared with the reference SC formed by the conventional assembly technique, this integrated SC shows much better performance in terms of larger areal capacitance (341.7 mF cm⁻² at 0.25 mA cm⁻²), better cycling retention (92.8% of the capacity retained after 6500 cycles), and higher volumetric energy and power density (1.7 m Wh cm⁻³ at 73.9 mW cm⁻³; note that the whole SC volume is involved). Moreover, the energy density only degrades slightly with increasing the power density; therefore, high energy density and high power density can be simultaneously obtained for this integrated SC. This integrated SC also exhibits ultra-high flexibility and strong mechanical stability, and negligible capacity loss occurs even when the SC is rolled up. A self-powered system is also demonstrated by using the integrated SCs as the energy-storage component.