Improved capacitive performance of polypyrrole-based composite hydrogel for flexible self-powered sensing system

Developing all-gel supercapacitors with high capacitance and stretchability remains a challenge. Herein, high mass of electroactive anthraquinonemonosulfonate(AQS)-doped polypyrrole (PPy) nanoparticles templated by poly(vinyl alcohol) (PVA) have been loaded into poly(acrylic acid) (PAA) hydrogel. The extra energy storage of AQS significantly enhances the electrochemical performance of the obtained PPy-AQS-PVA/PAA hydrogel electrodes. As a result, the assembled symmetrical supercapacitor can deliver a large areal specific capacitance of 392.5 mF/cm2, a high energy density of 34.89 μWh/cm2 and an enhanced cycling performance with 118% capacitance retention after 5000 CV cycles. Besides, such a device can work normally under various deformations and at extreme temperatures. Notably, the PPy-AQS-PVA/PAA hydrogels exhibit sustainable sensing capability for strain. When integrated the flexible supercapacitor with the strain sensor, a promising self-powered sensing system can monitor both large and subtle human movements accurately. Therefore, the multifunctional conductive PPy-AQS-PVA/PAA hydrogels have great potential in flexible electronic devices.