Preparation Of Three Coal Tar Pitch-Based Porous Carbon And Their Capacitive Properties Research

Porous carbon material has large specific surface area,good electrical conductivity,and strong chemical stability.As an electrode material,it adsorbs ions in the electrolyte by electrostatic action,in order to storing electrical energy in electric double layer between the electrode material and the electrolyte.Supercapacitors made of porous carbon materials have good cycle stability,but the energy density is low.Therefore,chemical activation is used to increase the specific surface area of carbon materials to increase their specific capacitance.As a by-product of coal coking process,coal tar pitch?CTP?is a porous carbon material precursor with wide source and low cost,and their main components are fused aromatic hydrocarbons of different condensing degrees.In this paper,CTP is used as raw material?carbon precursor?,which is treated by three different chemical methods,and porous carbon materials with larger specific surface area are prepared.We studied their electrochemical properties.The main work as follows:?1?PO?Pitch Oxide?,is prepared by oxidation treatment of coal tar pitch by concentrated sulfuric acid and concentrated nitric acid.The carboxyl group and sulfonic acid group of PO dissolved in water,the hydrogen ion ionized,The process can boost the dissolution of aniline in water.By adding a certain amount of ammonium persulfate?APS?to the mixed solution of PO and aniline in order to forcing oxidative polymerization.During the polymerization,PO as anion dopant is coprecipitated with polyaniline to prepare PANI/PO composite.By KOH activation,Nitrogen-doped porous carbon material is obtained.Through optimizing conditions,the product PO-PANI-800 can reach 303 F·g^-1 capacitance and can be retained 90.4% capacitance value after 2000 cycles.?2?PO can form a gel in an ammonia solutionis,by introducing nickel-ammonia ion react with PO to prepare gel,after carbonization?KOH activation and dilute HCl treatment.The capacitance value of PC-0.4 can reach 248 F·g^-1.After 10000 cycles,the capacitance value can be retained 86.1%.However,the carbon yield of such a porous carbon is low,and the purification operation of the precursor PO in the preparation process is cumbersome.?3?Coal tar pitch was used as a raw material,KCl-Na Cl molten salt mixed with it.Then pre-oxidation was carried out in an air atmosphere of 400?,450? and 500?.In the process of the experiment,the molten salt plays a role of template,and can direcly induce carbon microcrystallites in coal tar pitch to form ordered structure.Among them,the optimized capacitor assembled of MS-Pitch-450-850 can reach 280 F·g^-1,and it can maintain 92.1% after 2000 cycles.