A novel fiber-shaped asymmetric supercapacitor prepared by twisting carbon fiber/carbon nanotube/MnO2 and carbon fiber/carbon nanotube/polypyrrole electrodes+

In the study, a novel fiber-shaped asymmetric supercapacitor with high specific capacitance has been successfully constructed by twisting two self-made composite electrodes. Prior to manufacturing these electrodes, carbon nanotube is first deposited on carbon fiber by electrophoretic deposition to obtain carbon fiber/carbon nanotube composites. Subsequently, the positive and negative composite electrodes are prepared by the electrochemical deposition of manganese dioxide and electrochemical polymerization of polypyrrole, respectively. As a result, the novel fiber-shaped asymmetric supercapacitor performs a wide potential window of 1.7 V and a high energy density of 22.8 μWh cm−1 at the current density of 0.5 A g−1. Meanwhile, it still maintains great capacitance retention of 91.6% and 86.1% from 500 bending repetitions and 5000 cycles, respectively, which is due to the excellent flexibility and long cycle life. It is significant that the promising performance of the novel fiber-shaped asymmetric supercapacitor is of greatly potential for portable and wearable electronics in the future.