With the wide applications of intelligent wearable devices in various fields, developing a new generation of flexible energy storage devices has become a major challenge for the current technology. As a wide application of wearable flexible substrate, cotton fabric has the advantages over low price, non-toxic and environmental friendly, but the poor conductivity becomes a major problem limiting its development. As a nitrogen-containing conducting polymer, polypyrrole is traditionally used as electrode materials, but poor mechanical performance and cycle stability severely limit its application in electrode materials. In this article, a self-supporting flexible nitrogen-doped carbon fabric electrode was prepared by in situ polymerization-high temperature calcination method using cotton as a substrate and polypyrrole as a nitrogen source. The high temperature carbonization transformed the non-conductive cotton fabric into a good conductive carbon fabric while retaining its original three-dimensional structure and the nitrogen was mixed into carbon materials at the same time. The structure was characterized by Fourier infrared spectroscopy, specific surface area test, scanning electron microscopy and X-ray photoelectron spectroscopy. The results demonstrated that the cotton fiber was uniformly coated by polypyrrole that was subsequently carbonized into nanocarbon, the specific surface area of the obtained nitrogen-doped carbon (N-CT) electrode was 495.0 m2·g-1 and the nitrogen content was 2.26%. The electrochemical performance test showed that the N-CT electrode had a capacitance of 256.2 F·g-1 at a current density of 0.5 A·g-1. The stability test revealed that the capacitance retention was 98.3% and the coulomb effciency was about 98.8% after 5000 charge-discharge cycles. Meanwhile, the N-CT electrode exhibited good flexibility and mechanical properties.
