Synergistically enhanced electrochemical performance using N-rich multilayered carbon nanofibers

Abstract

N-rich multilayered carbon nanofibers with hollow channels (PPMPN) are fabricated to fully utilize the mesopores, micropores, and nitrogen-functional groups of carbon nanofibers (CNFs) for superior electrochemical properties. Among all composites, the PPMPN(10) exhibits high specific surface area (570 m2g−1) with mesopore volume fraction (42%) and rich surface functionalities (∼7.25at% nitrogen and ∼ 16.1at% oxygen), helping to improveelectrochemical performance. The performance of the symmetric supercapacitor of the PPMPN was significantly improved in terms of its specific capacitance of 189 Fg−1 at 1 mAcm−2, good retention of 80% (when the current density is increased from 1 to 20 mAcm−2), energy density of 23.5 Whkg−1 at a power density of 400 Wkg−1, and cycling stability of 94% for 10,000 cycles. The top layer plays a role in charge storage/transport by increasing electrical conductivity due to N-functional groups. The intermediate layer with tubular 1D nanostructures enhances the diffusion of electrolyte ions even at higher current densities. The bottom layer composed of numerous micropores serves as a charge storage layer. Therefore, in the multilayer CNF, the micropores/mesopores and N-functional properties of each layer do not interfere with each other, and the advantages of the factors of each layer are maximized in the electrochemical properties.