|dc.description.abstract||Using carbon as an electrode, the supercapacitor not only has the advantage of reducing material costs, but also is applicable to a wider temperature range. In this study, the carbon-based nanofiber membrane electrode, for an electric double layer capacitor, was fabricated by the techniques of electrospinning and a follow-up laser carbonization. The fibers prepared by electrospinning take the advantage of excellent fiber continuity that leads to better electrode conductivity and lower internal resistance on the resulting supercapacitor. The characteristics of cavities and holes on the laser-carbonized nanofibers are beneficial for the electrodes of electric double layer capacitors. The rapid heating rate of the laser increases the number of holes in the nanofibers, thereby successfully improving the capacitance effect.
Compared with traditional tube furnace heating for carbonization, the heating and cooling cycles often take several hours, laser carbonization can reduce the processing time to several minutes or even tens of seconds. The laser can use less energy to raise the carbonization temperature to a higher level, increasing the energy use efficiency. A higher carbonization temperature also leads to a better degree of graphitization, which makes the carbon nanofiber electrode be more conductive. Therefore, the carbon nanofiber electrodes used in electric double-layer capacitors, that are obtained by electrospinning and laser carbonization, can not only improve production efficiency, but also effectively improves electrode performance.
Results show that the diameter of the carbon nanofibers fabricated in this study is about 300 nm. Without any activation process, the specific surface area can reach 33.63 m²/g. When using 3M KOH as the electrolyte and characterized using a three-electrode tester, the specific capacitance is measured to be 21.66 F/g that is several times higher than the carbon nanofiber electrodes obtained by heating in a traditional tube furnace.||en_US|