Conducting polymer/hydrogel hybrid free-standing electrodes for flexible supercapacitors capable of self-sensing working conditions: large-scale fabrication through facile and low-cost route

Abstract

Abstract Search for energy storage devices towards sustainability, compatibility and versatility demands flexible supercapacitors capable of sensing their surrounding conditions. Here, highly electroactive polyaniline/chitosan-hydrogel hybrid films were fabricated with a view to developing a self-sensing motor. The hybrid electrodes showed remarkable supercpacitive property with high-rate performance while capable of sensing electrical, thermal and chemical working conditions as evinced from the chronopotentiometric responses with consumed electrical energy as the sensing parameter. A single faradaic electrochemical reaction (the reversible oxidation-reduction) is responsible for both the sensing and charge storage properties of the hybrid film, which is exploited to develop a truly integrated sensing supercapacitor without additional connectivities. As a proof-of-concept, an all-solid-state symmetric supercapacitor was fabricated which showed large capacitance (118 mF cm− 2 at 0.4 mA cm− 2), high energy density (14.8 µWh cm− 2 at a power density of 105 µW cm− 2) compared to other polyaniline-hydrogel supercapacitors as well as 93% capacitance retention after 1200 charge-discharge cycles. Besides, the current sensing characteristics of the device were tested from charge-discharge responses at a constant charged state to prove the above concept. This fundamental study provides a new direction for the development of simple and compatible self-sensing motors.