Multilayered Flexible Fibers with High Performance for Wearable Supercapacitor Applications

Abstract

Multilayered flexible fibers, consisting of carbon black–carbon nanotube fibers, manganese oxides, and conducting polymers, are fabricated for use as electrodes in supercapacitors. Carbon-based fibers are initially prepared by wet-spinning using carbon-based nanomaterials (carbon black and carbon nanotubes) and chitosan as a matrix. Subsequent coatings with manganese oxides and conducting polymers form a multilayered structure. Different MnO2 crystalline structures (ε-MnO2, γ-MnO2) are grown onto the fiber by electrodeposition and different conducting polymers (polyethylenedioxythiophene and polypyrrole) used as a conductive wrapping. Each layer improves the performance of the fiber by adding different functionalities. While MnO2 improves the capacitance of the fiber, the presence of conducting polymers creates a conductive network increasing the capacitance further and conferring cycling stability. Capacitance values up 600 F g−1 and capacitance retention of 90% can be achieved with these multilayered hybrid fibers. A symmetric supercapacitor device, prepared from two hybrid fibers, shows no significant change in properties when the device is bent, demonstrating their potential in flexible electronic devices and wearable energy systems.