Polypyrrole-based hybrid nanostructures grown on textile for wearable supercapacitors

In the development of wearable energy devices, polypyrrole (PPy) is considered as a promising electrode material owing to its high capacitance and good mechanical flexibility. Herein, we report a PPy-based hybrid structure consisting of vertical PPy nanotube arrays and carbon nano-onions (CNOs) grown on textile for wearable supercapacitors. In this hybrid nanostructure, the vertical PPy nanotubes provide straight and superhighways for electron and ion transport, boosting the energy storage; while the CNOs mainly act as a conductivity retainer for the underlayered PPy film during stretching. A facile template-degrading method is developed for the large-area growth of the PPy-based hybrid nanostructures on the textile through one-step polymerization process. The fabricated stretchable supercapacitor exhibits superior energy storage capacitance with the specific capacitance of 64 Fg(-1). Also, it presents the high capacitance retention of 99% at a strain of 50% after 500 stretching cycles. Furthermore, we demonstrate that the textile-based stretchable supercapacitor device can provide a stable energy storage performance in different wearable situations for practical applications. The use of the PPy-based hybrid nanostructures as the supercapacitor electrode offers a novel structure design and a promising opportunity for wearable power supply in real applications.