A dynamic stretchable and self-healable supercapacitor with a CNT/graphene/PANI composite film

Conventional flexible supercapacitors can work under consecutive bending, folding and even twisting without performance degradation. Nevertheless, these devices can hardly be used under large tensile strain. Flexible stretchable and healable supercapacitors are highly desired due to their many potential applications in electric devices. However, it is challenging to fabricate supercapacitors that can withstand stretchability and self-healability. Herein, we report a stretchable and self-healable supercapacitor based on a carbon nanotube@graphene@PANI nanowire film. The supercapacitor possesses high energy density from 36.3 to 29.4 μW h cm^-2 with the corresponding power density changing from 0.17 to 5 mW cm^-2 at a current from 0.1 to 3 mA, and the highest capacitive performance can reach up to 261.5 mF cm^-2. In terms of the bending test, the supercapacitor can operate under different static bending angles and dynamic bending conditions with different bending frequencies, and the capacitance was merely affected. Moreover, the supercapacitor can sustain a tensile strain up to 180% and 80.2% capacitance retention after the 10^th healing cycle. This novel design integrating all stretchable and healable components provides a pathway toward the next generation of wearable energy devices in modern electronics.