One-dimensional hierarchical porous carbon nanofibers with cobalt oxide in a hollow channel for electrochemical applications

One-dimensional hierarchical porous carbon nanofibers (CNFs) embedded with Co3O4 nanoparticles in a hollow channel (PPMCo) are fabricated by coaxial electrospinning followed by thermal treatment. The degree to which the CNF surface is exposed to Co3O4 nanoparticles was controlled by the cobalt(II) acetate concentration. The well-controlled structure of PPMCo with porous structure, heteroatoms, and amorphous Co3O4 nanoparticles provided fast ion transport and large reaction surface area, resulting in effective ion migration to the active site and a high rate capacity of the electrode. Benefitting from the unique structure, the PPMCo supercapacitor electrodes displays a high specific capacitance of 188 Fg-1 at 1 mAcm-2, rate capability of 82% when the current density is increased from 1 to 20 mAcm-2, and cycling stability of 93% for 10,000 cycles. The good capacitive performance of the PPMCo electrode is attributed to the synergistic effect of the hierarchical porosity, electroactive material of Co3O4, high effective surface area, and polar effects by heteroatoms.