High mass loading of polypyrrole in conductive hydrogels for stretchable all-in-one supercapacitors and self-powered strain sensing system

Developing high mass loading of conducting polymers in hydrogels for flexible supercapacitors remains an enormous challenge. Herein, we demonstrate an effective and facile strategy for incorporating high mass-loading of polypyrrole (PPy) nanoparticles into an open porous polydopamine/polyacrylamide (PDA/PAAM) hydrogel substrate. The as-prepared PDA/PAAM/PPy hydrogels exhibit great stretchability and desirable self-healing properties. Taking advantage of the sandwiched configuration and high mass of electroactive PPy (up to 11.13 mg/cm2), the PDA/PAAM/PPy hydrogels could be directly used as all-in-one supercapacitors, which can deliver a superior specific capacitance of 860 mF/cm2 at 1.0 mA/cm2, an excellent energy density of 76.44 μWh/cm2, a maximum power density of 4 mW/cm2, and excellent capacitance retention of 85 % after 5000 cycles. What’s more, the PDA/PAAM/PPy hydrogels show significant strain-sensitive behavior. A self-powered sensing system integrating the supercapacitor and strain sensor is achieved to monitor various human motions. Therefore, the resultant hydrogels have potential applications in wearable electronics.