The Studies On Preparation, Activation And Supercapacitive Behaviors Of Calcium Carbide Derived Carbons Material

As a specific and new type energy storage device by combining batteries andtraditional capacitors, supercapacitors have received a significant amount of attentionbecause of their various advantages, such as long-lived cycle life, fastcharge/discharge and high power density. And it is well known that the key ofdevelopment of supercapacitors depends mainly upon the development of theelectrode material with high performance. Traditionally, the most suitable electrodematerials for supercapacitors are porous carbon materials which possess high specificsurface areas and wide pore size distribution. Calcium carbide skeleton carbons areextensively investigated as the electrode materials for energy storage devices due totheir controllable pore size and microcosmic structures. In this paper, calcium carbideskeleton carbons （CCDCs） are synthesized in the temperature range of400⁸00Cfrom CaC2in a freshly prepared chlorine environment. Furthermore, the effects ofpreparation temperature, aqueous electrolytes and activation technology on bothphysical properties and electrochemical performance of CCDCs are studied.Various Calcium carbide skeleton carbons are prepared by adjusting chlorinationtemperature. The morphologies of CCDCs are characterized by Field EmissionTransmission Electron Microscope （FE-TEM） and X-ray diffraction （XRD）. And thespecific surface areas and pore size distribution of CCDCs are measured by nitrogenadsorption/desorption isotherms at77K. The results show that the as-prepared porouscarbon materials possess a certain degree of micro-meso-macro structures. The porouscarbon materials （marked with CCDC-600） with the most excellent electrochemicalperformance are obtained when the chlorination temperature is600oC, and thehighest specific surface areas of CCDC-600is652.82m²g^-1, the highest specificcapacitance of CCDC-600electrode obtained from CV is214.4F g^-1at the scan rateof1mV s^-1in6.0M KOH electrolyte.The CCDCs with chlorination temperature of600oC are activated by H₃PO₄,ZnCl₂and KOH. The effects of activated method of CCDCs on physical propertiesand electrochemical performance are discussed. The results show the pore size,specific surface areas and pore volume of the activated CCDCs are apparentlyimproved. Compared to the original CCDCs, the electrochemical behaviors of theactivated CCDCs are improved. Especially, the CCDCs activated by KOH show theexcellent properties, including the highest specific capacitance and the stable cycle life.The CCDCs with chlorination temperature of600oC which are activated byKOH are used as the electrode materials of supercapacitors, and the electrochemicalperformances of supercapacitors in0.5M K₂SO₄,2M KCl,1M KNO₃and6M KOHaqueous electrolytes are discussed. The results display that the supercapacitor in6MKOH aqueous electrolyte exhibits the best electrochemical properties, and the specificcapacitance of the supercapacitor in6M KOH is the highest, it stabilized still at afixed value even after5000cycles.