Morphology And Composition Of Carbon Materail For Supercapacitor Electrode Materials

More and more attention has been paid attention to supercapacitors due to their extra long cycle life and fast charge and release.As an electrode material for supercapacitors,the morphology and composition of porous carbon are important factors affecting the performance of electric double layer capacitors.In this thesis,both different carbon materials such as porous carbon and carbon nanotubes and their components were further regulated,and the acquisition is porous carbon/CNT nanocomposite electrode material doped in situ by Co₃S₄/Co.The structure is characterized by XRD,SEM,TEM,FT-IR,XPS,Raman and so on,and the capacitance and kinetics of the battery are tested by blue battery performance tester and electrochemical workstation.Selecting the Artemia egg shell as the carbon source,the owned porous carbon material is made into electrode material doped with hetero atoms such as N and O.And the specific capacity can reach 301F g^-11 under the current density of 0.5 A g^-1,even the current density is as large as 5 A g^-1（10 times）,it can be as high as 75%.Further,the porous carbon/thin-walled CNT composite electrode material consists of in-situ of bamboo-like thin-walled carbon nanotubes in porous carbon with high heteroatoms such as N and O by a modified CVD method.The results show that the thin-walled CNT can further improve the rate discharge performance,which the retention rate is increased to84.7%with a 9-fold increase(5 A g^-1)in current density.The metal organic framework material MOF has attracted massive attention due to its adjustable aperture and orderly structure.Prepared by a simple method,ZIF-67 with a rhombohedral dodecahedral structure is carbonized at high temperature,getting a Co-doped porous carbon material in this paper.With the catalytic effect of Co,carbon nanotubes are grown in situ in porous carbon.Further,a tantalum capacitor electrode material Co₃S₄ is prepared by vulcanization to obtain a Co₃S₄/Co/C/CNT nanocomposite electrode material.The material has a specific discharge capacity of 380 F g^-11 at 0.5 A g^-1,its capacity is still as high as 330 F g^-1（86.8%）with a 9-fold increase(5 A g^-1)in current density,indicating the excellent rate discharge performance.In addition,the capacity retention rate is 95%after 5000 cycles of testing,showing the wonderful cycle stability.In order to study its practical performance,an asymmetric capacitor assembled with the Co₃S₄/Co/C/CNT nanocomposite electrode material and activated carbon electrode shows the energy density of 41.3 Wh kg^-11 at the power density of 691.9 W kg^-1.When the power density is expanded to 4.5 times,the energy density is still 33.1 Wh kg-1（80%）,and its capacity retention rate is 93.7%after 10,000 cycles.