Rational synthesis of MnO ₂/conducting polypyrrole@carbon nanofiber triaxial nano-cables for high-performance supercapacitors

This study presents a rational synthesis of hierarchical MnO ₂/conducting polypyrrole (PPy)@carbon nanofiber (CNF) triaxial nano-cables via in situ interfacial redox reaction. Uniform MnO ₂/PPy multifunctional nanocoatings (∼20 nm) are formed on individual electrospun CNFs, constructing a one-dimensional triaxial configuration. The unique architecture enables a maximum value of the MnO ₂/PPy pseudocapacitance and a strong synergetic effect of each component. The specific capacitance of the ternary nanocomposite as a freestanding electrode reaches as high as 705 F g ^-1 at 2 mV s ^-1. The three-dimensional porous electrode facilitates a large mass loading of active materials up to 2.0 mg cm ^-2, which leads to a high areal capacitance of 1.4 F cm ^-2. The improved electrical conductivity and strong structural integrity of the nanocomposite also endow the electrodes with good rate capability and long-term cycling stability. The superior electrochemical performance indicates that this method is an effective strategy for developing multifunctional nanocomposite electrodes for energy storage devices.