Multilayered Flexible Fibers with High Performance for Wearable Supercapacitor Applications

Multilayered flexible fibers, consisting of carbon black-carbon nanotube fibers, manganese oxides and conducting polymers, were fabricated for use as electrodes in supercapacitors. Carbon-based fibers were 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 (e-MnO2, γ-MnO2) were grown onto the fibre by electrodeposition and different conducting polymers (polyethylenedioxythiophene and polypyrrole) used as a conductive wrapping. Each layer improved the performance of the fibre by adding different functionalities. While MnO2 improved the capacitance of the fibre, 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 fibres showed no significant change in properties when the device was bent, demonstrating their potential in flexible electronic devices and wearable energy systems.