Carbon Nanofibers As a Conductive Additive for Supercapacitor Electrodes

The effect of electrically conductive additives in the active layer of electrodes on the electrochemical parameters of supercapacitor cells was studied. Carbon nanofibers (CNFs) obtained by pyrolysis of hydrocarbon mixtures (propane, butane, and isobutane) were used as a conductive additive. The obtained carbon nanofibers were introduced into the active layer of the carbon electrode at 10 to 40 wt %. The electrochemical characteristics of the electrodes were studied by galvanostatic charge–discharge and cyclic voltammetry in the range from 0 to 2.7 V. The impedance spectra were measured in the frequency range from 100 kHz to 10 mHz with an alternating current voltage of 10 mV. A 1 M solution of 1,1-dimethylpyrrolidinium tetrafluoroborate in acetonitrile was used as an electrolyte. The content of of carbon nanofibers in the active electrode layer decreases the internal electrical resistance of the supercapacitor cell. The use of carbon nanofibers at 30 wt % in the active layer leads to a decrease in the internal series resistance and also increases the speed of ions inside the pores of the active electrode layer. The use of carbon nanofibers at up to 40 wt % leads to a decrease in the total specific surface area of the active layer, which reduces the specific capacity of the cells.