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

Abstract

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 °C to 61 °C.