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The Synthesis,Modification And Supercapacitive Properties Of Biomass Derived Carbon Nanostructures

Posted on:2018-06-07Degree:MasterType:Thesis
Country:ChinaCandidate:K WuFull Text:PDF
GTID:2381330605452384Subject:Materials Science and Engineering
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Supercapacitor is a kind of energy storage device which is widely used in high power devices due to its high power density.According to the theory,it can be divided into two kinds:the electric double-layer and pseudo-capacitors.The electric double-layer capacitor has more excellent cycle stability compared to the pseudo-capacitor.Carbon material is a material of double layer capacitor,and it is also the main commercial electrode material.How to prepare low cost and high performance carbon materials has become a hot topic in the field of supercapacitors.Because of its low cost and stable structure,biomass is the ideal precursor for preparing carbon electrode material.In this paper,on the one hand the graphene sheet carbon from water hyacinth was prepared for electric double layer porous,on the other hand the 3D carbon materials with nitrogen doping from letinous edodes was used for pseudo capacitance.(1)Porous graphene was prepared by chemical activator KOH with water hyacinth after hydrothermal treatment.When C with KOH were mixed at a mass ratio of 1:1under annealing temperature of 800 oC,the two-dimensional porous structure is beneficial to the storage of electrolyte and the ionic transfer of electrolyte according to the experimental results.In the three-electrode environment,when the current density is 1 A g-1,the specific capacity is 273 F g-1.When the current density is went up to 50times,the capacity retention rate is still reached 75%。In addition to after 10000cycles,the capacitance retention rate is still as high as 99%.(2)Three-dimensional porous carbon was made by materials by chemical activator KOH with carbon precursor mushroom.3D porous carbon with N doping were prepared through hydrothermal with urea.Due to the high specific surface area,suitable pore size distribution and uniform nitrogen doping,the 3D carbon materials exhibit excellent electrochemical performances.In the three-electrode environment,when the current density is 1 A g-1,the specific capacity is up to 317.5 F g-1.When the current density increased 10 times,the specific capacity remained at 259 F in g-1,after 10000 cycles the capacitance retention rate is still as high as 99%.
Keywords/Search Tags:Carbon material, Biomass, Graphene, Nitrogen doping, Supercapacitor
PDF Full Text Request
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