A N-doped Cobalt@graphitized carbon material derived from ZIF-67 assisted polyvinylidene fluoride hollow fiber membrane for supercapacitors

Abstract

In this work, a porous nanostructure active carbon material (N-doped Co@graphitized carbon) for supercapacitor is prepared from a ZIF-67 assisted polyvinylidene fluoride (PVDF) hollow fiber membrane by a simple anaerobic calcination method at a relative low temperature (600 °C). The addition of ZIF-67 can prevent the porous structure of PVDF hollow fiber membranes from collapsing during the calcination process, meanwhile the PVDF membranes can also prevent the Co particles derived from ZIF-67 aggregating together. At the same time, the doped N can increase the conductivity and wettability of the carbon material and generate pseudocapacitance effect. Furthermore, the obtained unique Co@C core@shell structure can improve the electrochemical activity of the carbon material. Under the synergistic effects of the above factors, the prepared active material delivers a specific capacitance of 652 F g−1 at 1 A g−1. Even at 10 A g−1, it still remains 97.1% retention rate after 20,000 cycles.