High performance of stretchable carbon nanotube-polypyrrole fiber supercapacitors under dynamic deformation and temperature variation

Flexible fiber-shaped supercapacitors have great potential in wearable electronic devices. Here, we fabricate CNT-PPy composite films by an electrochemical deposition method from macroscopic CNT films. The composite films are transformed into flexible fibers with ultralow density by drawing through several diamond wire-drawing dies. The CNT-PPy fibers have outstanding electrochemical properties with a high specific capacitance of 302 F g(-1) in 1 M H2SO4 liquid electrolyte. Flexible, stretchable, all-solid-state, fiber-shaped supercapacitors are then fabricated from the CNT-PPy fibers using H3PO4-poly(vinyl alcohol) as gel electrolyte. The supercapacitor has a high specific capacitance of 69 F g(-1), a high power density and an energy density of 3.8 kW kg(-1) and 3.6 W h kg(-1), respectively. The fiber-shaped supercapacitor also exhibits high stability and reliability under static and dynamic stretching, and also in a wide temperature range from -27 degrees C to 61 degrees C.