Heterogeneous graphene/polypyrrole multilayered microtube with enhanced capacitance

Fiber-shaped supercapacitor is a prevailing flexible energy storage device due to its high power density, good cyclic ability and excellent flexibility. However, the limited variability of fiber structures hinders its further increase in specific capacitance. Here, a facile electrochemical deposition method is developed to fabricate a novel graphene/polypyrrole (PPy) heterogeneous multilayered microtube. The graphene/PPy microtube possesses an enhanced specific capacitance, which is three times the value of graphene microtube. The superb performance benefits from combined merits, e.g., higher conductivity, faster charge transfer and ion diffusion, and more stored energy by PPy. Moreover, the graphene/PPy multilayered microtube exceeds almost all the available graphene fibers and PPy-based fibers in gravimetric specific capacitance, which sheds new light on fiber-shaped supercapacitors.