The performance of supercapacitors is strongly influenced by the performance of electrode materials. The cobalt-sulfur compounds are used as electrode materials due to their wide range of sources, low price, and high conductivity. It was found that higher number of electron-hole pairs and higher conductivity could be provided by sulfidation. This is related to the mixing valence of Co in the cobalt sulfur compound, which promotes electron transfer to the electrolyte. During the charging and discharging process, CoS2 is not easy to fall off from the surface of carbon nanofibers, thus increasing the doubling rate and cycling stability, due to the one-dimensional morphology of the interconnected conductive paths and excellent mechanical stability. At the current density of 1Ag−1, the specific capacitance of CoS2-CNFs reaches 488.0Fg−1, over 74% of initial capacitance is retained as the current density improves from 1 to 10Ag−1, and it also exhibits an excellent cycling performance with 91.0% capacitance retention after 1000 times charge/discharge cycles (at the current density of 1Ag−1). © 2020, Springer-Verlag GmbH Germany, part of Springer Nature.