Preparation Of Sunflower And Grapefruit Skin Base Porous Carbon And Its Application In Supercapacitor

With the accelerated process of global industrialization and the consumption of fossil resources,the non-renewable resource for human survival is exhausted. So, it is the urgent task to explore a new carbon source ensured the human survival and the sustainable development of human society. Supercapacitors, alsocalled electrochemical capacitors, have caused wide public concern recently as a kind of energy storage devices that have high power density, long cyclic stability, and can be charged and discharged rapidly. Renewable bio-wastehas becomepreferred raw materials of supercapacitorselectrodedue to its low cost, the wide raw material sources and reproducibility, which can reduce the cost and relievethe environmental pollutioncaused by the direct burning of themselves.In this dissertation, we select two kinds of biowastes(sunflower heads and pomelo peels) as the precursors of carbonmaterials. Various carbon materials have been produced by different methods. Thecorresponding properties of these materials have been thoroughly investigated. The study provided the scientific basis for high value comprehensive utilization of bio-waste. The main points were as follows:Activated carbonderived from sunflower heads was prepared by KOH activation. We discuss two kinds of activation methods( grindingactivation and impregationactivation) and the proportion of activator. The effect of activation conditions on the structure and properties of activated carbon had been examined.These activated carbons exhibited high specific surface area, the corresponding specific surface area and total pore volume has reached 1031 m2·g-1and 2.34 cm3·g-1, respectively.Characterizations revealsthat the sample has a lot of micropores and a small amount mesopores.The results of electrochemical tests indicated that the specific capacitance value of the sample was about 345 F·g-1 at the current density of 1 A·g-1.Porous carbon materialsderived from sunflower heads and pomelo peels were preparated with dualtemplates method. A CTAB/TEOS dual templates method has been developed to prepare porous carbons,in which sunflower heads and pomelo peels respectively serve as carbon source. After high temperature roasting under N2, the template agent s were washed by hydrofluoric acid(HF). Analyzing with characterization test and electrochemical measurement,porous carbon materials derived from pomelo peels with mass ratio of CTAB and TEOS is 2/5 show better electrochemicalperformance.The nternalresistancewas low and the capacitancewas high,about 295 F·g-1. While the electrochemical performance of porous carbon materials derived from sunflower heads was a bit poor,which lays a foundation for selecting carbon precursor.Hierarchicalporecarbons derived from pomelo peels were synthesizedusingmagnesiumacetatepyrolysis MgO as a temple and KOH as activator.The influence of activator proportion andcalcination temperature on the electrochemicalperformance was investigated by some electrochemical techniques. The relationshipbetweenpore structure and capacitance was analyzed by N2 adsorption and desorption,transmission electron microscope,scanning electron microscopy,Raman spectrum andX ray diffraction.Among these materials,optimal carbonmaterial appeared the highest capacitance,which was353 F·g-1(1 A·g-1).