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The Preparation Of Hierarchical Porous Poly (Bisphenoxy) Phosphazene Based Carbon Material For High-performance Supercapacitors

Posted on:2018-06-07Degree:MasterType:Thesis
Country:ChinaCandidate:C Y ZhangFull Text:PDF
GTID:2322330518994373Subject:Materials Science and Engineering
Abstract/Summary:PDF Full Text Request
With the popularity of protable typewriter,intelligent electronic equipment and electric vehicle,the demand for the reliable,stable and sustainable high-power density energy storage devices is increasing.In recent years,supercapacitor as a class of excellent energy storage device has attracted extensive attention because of its high power capacity,long cycle life,clean pollution and other characteristics.In general,the supercapacitor can be divided into two categories according to the different energy storage mechanism.One type is the electrical double layer capacitor(EDLC),the capacitance is from the static charges accumulation at the electrode and electrolyte contact interface,so the capacitance value is closely related to the specific surface area of electrode material.Another type is the pseudo-capacitor,the high specific capacitance value is generated by the rapid and reversible Faraday redox reaction due to the presence of active particles.It is found that the rich micropores can enhance the electrical double layer capacitance,but the electrolyte ions are difficult to penetrate into the micropores.How to improve the ion transfer rate in porous carbon,especially the ion transfer rate at high current density becomes an urgent problem.Therefore,it is the focus of research to create a hierarchical pore structure in the carbon material and to improve the ion transport rate in the micropores.Doped with heteroatoms is one of the effective methods to improve the pseudo-capacitance.In this paper,the hierarchical structure of porous carbon with high specific surface area is prepared by employed the poly(bisphenoxy)phosphazene rich in nitrogen,phosphorus and oxygen heteroatoms synthesized by the laboratory as carbon precursors and the method of doping sodium bicarbonate(NaHCO3).At the same time,the structure and element composition of the materials were analyzed by XRD,Raman,SEM,XPS,N2 adsorption-desorption.The capacitance performance was systematically evaluated by cyclic voltammetry(CV),constant current charge and discharge(GC),impedance and other electrochemical performance tested by electrochemical workstation.The specific research contents are as follows:(1)The nitrogen-phosphorus-oxygen co-doped hierarchical structure porous carbon material was prepared by the combination of solvent evaporation and high temperature pyrolysis method with the poly(bisphenoxy)phosphazene(PBPP)as carbon source and heteroatom source(N,P,O),NaHC03 as self-blowing agent,KOH as activator.Change the mass doping ratio of the self-expanding agent 10:1?10:10(PBPP:NaHCO3).The morphology and structure of the materials were characterized by SEM,TEM,XPS,XRD,Raman,N2 adsorption and desorption analysis,the properties of the carbon materials were characterized by electrochemical test.The morphology and properties of the prepared hierarchical structure of porous carbon materials were investigated by the effects of different self-expanding agents doping content.(2)As the amount of NaHCO3 doping increases,the repeatability of the specific capacitance of the PZCs carbon material get deteriorated.Therefore,select the better and more stable doping mass ratio is 10:5(PBPP:NaHCO3),change the temperature of the carbonation process(600/700/800/900?).The morphology and electrochemical properties of the prepared hierarchical structure of porous carbon materials were investigated by the effect of different carbonization temperature.(3)Select the NaHC03 doping mass ratio was 10:5,the carbonization temperature was 800?and change the amount of activator KOH(1:2/1:3/1:4)during the activation.The morphology and electrochemical properties of the prepared hierarchical structure of porous carbon materials were investigated by the effects of different KOH ratio.
Keywords/Search Tags:Supercapacitor, NaHCO3 doping, hierarchical structure, heteroatom doping carbon material
PDF Full Text Request
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