Research On Preparation And Capacitance Performance Of Nano-carbon Fiber Composite Self-supporting Electrode

As a new type of green environment-friendly energy storage device,the supercapacitor has a wide application prospect.As a key component of the super capacitor,the electrode material directly influences the performance of the super capacitor.Conventional supercapacitor electrode materials,such as carbon materials and metal oxide materials,have their respective advantages and disadvantages.The carbon electrode material has the advantages of long cycle life,good electrical conductivity,but low specific capacitance.The metal oxide electrode material is of larger capacitance,but poor conductivity,resulting in low rate performance and cycling life.The preparation of electrode materials with excellent comprehensive electrochemical properties is still a great challenge.Based on the phenolic resin-based nano-carbon fiber,three kinds of carbon fiber self-supporting composite electrode materials were prepared by loading Ni Co₂O_4.The research contents are as follows:?1?Using phenolic resin-based carbon nanofiber as substrate material,cobalt nitrate as cobalt source and nickel nitrate as nickel source,nickel cobalt@nanocarbon fiber self-supporting composite electrode material?Ni Co₂O₄@CNF?was prepared by hydrothermal deposition,followed by further heat treatment.The composite electrode material has excellent electrochemical performance.When the current density is 1 A·g^-1,the specific capacitance reaches 368 F·g^-1.?2?Using phenolic resin-based carbon nanofiber as substrate material,cobalt nitrate as cobalt source,nickel nitrate as nickel source and carbon black as additive,nickel cobalt/carbon black@nanocarbon fiber self-supporting composite electrode material?Ni Co₂O₄/CB@CNF?was prepared by hydrothermal deposition,followed by further heat treatment.The addition of carbon black significantly increased the conductivity of the electrode,and thus effectively improved the capacitance performance of the electrode.When the current density is 1 A·g^-1,the specific capacitance is 846 F·g^-1.?3?Using phenolic resin-based carbon nanofiber as substrate material,cobalt nitrate as cobalt source,nickel nitrate as nickel source,and deposited polydopamine on the surface by hydrothermal deposition,nickel cobalt/polydopamine carbon@nanofiber self-supporting composite electrode material?Ni Co₂O₄/PDAC@CNF?was prepared by further heat treatment.On the one hand,polydopamine carbon improved the conductivity,enhanced the structural stability of the composite electrode,boosted the rate and cycle performance of the electrode.On the other hand,the polydopamine carbon introduced a large number of functional groups,such as amino?-NH₂?and hydroxyl?-OH?,thus increased the false capacitance.When the current density is 1A·g^-1,the specific capacitance is 1392 F·g^-1.