Rational design of one-dimensional skin-core multilayer structure for electrospun carbon nanofibers with bicontinuous electron/ion transport toward high-performance supercapacitors

The fast transport of electrons and ions within electrodes is crucial to the final electrochemical properties. Herein, we have developed a unique ultra-long one-dimensional (1D) skin-core multilayer structure based on electrospun carbon nanofibers mainly through a facile Stöber method combined with resorcinol–formaldehyde resin, which not only achieves bicontinuous electron/ion transport during the charge/discharge process, but also provides large surface area for ion adsorption. Particularly, controlling the number of active layers as well as regulating the active sites in layer both can obviously improve capacitive properties. Benefiting from the synergistic effects of the desirable architecture, such the rational-designed skin-core structural carbon nanofibers as supercapacitor electrode can deliver a high specific capacitance up to 255 F g −1 at 0.5 A g −1 , favorable rate capability with 89% capacitance retention of initial capacitance at 8 A g −1 , and excellent cycling stability with nearly 93% capacity retention after 10,000 cycles at 2 A g −1 . Furthermore, the as-assembled symmetric supercapacitor devices also present a maximum energy density of 8.77 Wh kg −1 at 0.25 kW kg −1 and a maximum power density of 3.70 kW kg −1 at 6.74 Wh kg −1 . Such skin-core carbon nanofibers provide an effective strategy to design high-performance supercapacitor electrode for the next-generation energy storage devices.