Preparation And Capacitive Performance Research Of Nitrogen-containing Porous Carbon

As a novel environmentally friendly power storage device, supercapacitor hasreceived an increasing attention in recent years, which possesses the advantages of therechargeable batteries and traditional capacitors. Supercapacitors have its extentsiveapplication fields and tremendous market prospect, because this device not only haslong cycling life and wide scope of operating temperature, but also cancharge/discharge very fast, discharges with large pulse current and provides highspecific power density. Currently, carbon material is the most widely used material inall of the supercapacitor electrode materials owing to its advantage of high specificsurface areas, controllable pore distribution and surface chemical properties.Moreover, there are abundant raw materials in the nature, and the prepared process ofcarbon materials is more simple and practical. Thus far, many researchers havefocused on preparing the carbon material. However, how to prepare the carbonmaterial possessed high specific capacity and power density still need to researchfurthermore in the future.In this thesis, the primary works are the selection of nitrogen-containing carbonprecursor, the carbonization of the carbon precursor, and the optimization of the porestructure. Finally, the electrochemical performance of as prepared carbon material isoptimized through the process. As a consequence, the porous nitrogen-containingcarbon materials delivered high specific capacity and power density are prepared forelectrode material. The mainly works are listed as follow:In the first paper, the randomly disposed chicken feather is selected for carbonprecursor. The microporous material is prepared by the carbonization at450, followedby KOH activation with five weight ratios of KOH at800oC. Finally, the carbonmaterials possessed micropore and mesopore are prepared. The porous structure ofraw chicken feather carbon and activated carbon materials are characterized withHR-TEM and N2adsorption/desorption measurements. The activated chicken feathercarbon has a microporous specific surface area up to1575m2/g and average porediameter of1.863nm when the chicken feather carbon is activated by theKOH/carbon weight ratio of4:1(CFCA4). The electrochemical performancemeasurements demonstrate that CFCA4exhibits the superior electrochemicalperformance: CFCA4exhibites an average specific capacitance of253F/g and energy density of7.98Wh/kg at current density of1A/g. In addition, the specific capacitanceis still as high as167F/g and the power output is up to8.35kW/kg at current densityof10A/g.In the next studies, the cheap PAN and TPU are selected for carbon precursor.PMMA, TEOS acts as soft templates and hard templates, respectively. Thenitrogen-containing fibers are prepared through the electrospinning ofPAN/PMMA/TEOS and PAN/PMMA/TEOS/TPU polymer blend solutions.Subsequently, the hierarchical porous carbon nanofibers (HPCFs) are prepared by thecarbonization of the polymer spinning at high temperature and the removal of dualtemplates. In this experiment, the electrochemical performances of HPCFs areimproved through varying the weight ratio of dual templates and TPU. The porousstructures characterization of HPCFs demonstrate that the hierarchical porous carbonnanofibers that prepared by15/15%dual templates (HPCF15) and10%TPU (PT10)exhibits the optimal BET and microporous specific surface area. The electrochemicalmeasurements indicate that at current density of1A/g, the highest specificcapacitance of HPCF15and PT10is170,195F/g, respectively. And that even after8000cycles, the capacitance of HPCF15only fades5.8%of initial capacitance.However, the capacitance fading of PT10is approximate9.8%. Moreover, at currentdensity of10A/g, the specific capacitance of HPCF15and PT10is still stabilized at150and126F/g., respectively.