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Fabrication And Capacitive Properties Of CNT@graphene Core-shell Nanostructures

Posted on:2020-08-06Degree:MasterType:Thesis
Country:ChinaCandidate:K LiFull Text:PDF
GTID:2381330599951189Subject:Engineering
Abstract/Summary:PDF Full Text Request
Supercapacitors are clean and efficient,which have attracted much attention in energy device research.Among them,electrode materials are important factors in determining their specific capacitance.Carbon nanotubes?CNTs?and graphene have high specific surface area,excellent electrochemical stability and good electrical conductivity,and this is why they are preferred as supercapacitor electrode materials.In this paper,the two materials are combined in technologies to form a new material in order to achieve better performance.Using the polyvinyl alcohol?PVA?as carrier,disperse the catalyst precursor tetrachloroauric acid?HAuCl4?on the surface of CNT,and then a new CNT@Graphene nanocomposites with core-shell structure was prepared by DC arc plasma spray chemical vapor deposition.A sandwiched electrode structure was used to construct CNT@graphene/Ni flexible electrodes with different CNT@graphene mass loads.The electrochemical properties were tested in a gel electrolyte consisting of potassium hydroxide?KOH?and sodium carboxymethylcellulose?CMC?.The CNT@graphene/Ni electrode showed a high specific capacitance at a sweep rate of 1 mV s-1.The electrode with a mass load of 3 mg cm-22 showed a high specific capacitance of 620.3 F g-11 and area specific capacitance of 1121 mF cm-2.In addition,the flexible electrode has excellent rate performance,and the mass specific capacitance still reaches 123.4F g-11 at a current density of 10A g-1,and the area specific capacitance reaches 617.4mF cm-2.A symmetric flexible supercapacitor was constructed with 3 mg cm-22 of CNT@graphene/Ni electrode and gel electrolyte.The capacitor shows a high operating voltage of 1.8V,and the specific capacitance reaches 268.7 mF cm-22 at a sweep speed of 2mVs-1.The energy density of the capacitor was 76.3?Wh cm-22 for a power density of 1328.3?W cm-2,and the power density was 25110?W cm-22 for an energy density of 41.2?Wh cm-2.,The power density can reach 4185 W kg-1(25110?Wcm-2).After 10,000 cycles,the specific capacitance can maintain 120.4%of the initial specific capacitance,showing high cycle stability;under different angle bending conditions,the specific capacity can still maintain more than 94.1%,and the flexibility characteristics are obvious.
Keywords/Search Tags:graphene, carbon nanotube, core-shell structure, flexible supercapacitor, chemical vapor deposition
PDF Full Text Request
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