Construction And Electrochemical Performance Of Porous Carbon Nanomaterials For Supercapacitors

Carbon nanomaterials play an important role in promoting the development of modern science and technology and meeting the important strategic needs of high-power and high-energy storage devices.Therefore,carbon-based supercapacitors have broad application prospects in the field of electric vehicles,information technology,aerospace and national defense.Aiming at the problem of low charge storage efficiency,this paper creatively proposes a strategy of defect construction to accurately construct the porous carbon nanomaterials for solving the technical problem of low energy density of carbon nanomaterials.The specific research are as follows:(1)Aiming at the problem that carbon nanomaterials can't be customized ideally,this paper creatively proposes a newly molecular scissors tailoring strategy to realize the cutting of carbon nanomaterials in different dimensions and obtain the carbon nanomaterials with abundant defects and high conductivity for revealing the mechanism of molecular scissors and solving the technical problems of building carbon nanomaterials at the molecular level.Based on molecular scissors tailoring technology,the carbon nanomaterials have high specific surface area of 1685 m²g^-1and suitable pore size distribution.By optimizing the activity temperature and tailoring time of molecular scissors,this paper can successfully realize the controllable construction of different dimensional carbon nanomaterials.Moreover,by adjusting the tailoring activity of molecular scissors,this paper can successfully tailor the carbon nanomaterials.In the PVA/Na₂SO₄gel electrolyte,the tubular superstructure of nanocarbons-based flexible supercapacitor deliver a power density of 4.63m Wh cm^-3at a power density of 3520 m W cm^-3.(2)Aiming at the problem of inhomogeneous pore distribution caused by traditional KOH grinding activation,this paper creatively proposes a molecular pre-embedded strategy to realize the controllable construction of porous carbon fibers with high specific surface area and suitable pore size distribution for revealing the mechanism of vacancy defects.By optimizing the concentration of pre-embedded KOH molecule,this paper can precisely control the pore structure with different sizes.In the 6 M KOH electrolyte,the porous carbon fibers-based symmetrical supercapacitors deliver a power density of 5.89 Wh kg^-1at a power density of 0.25 k W kg^-1.Even if the power density is increased to 10 k W kg^-1,the energy density is still as high as 3.78 Wh kg^-1.Additionally,more than 92%capacitance can be retained after 10000 cycles.(3)Aiming at the problem t of the size matching between the biomass carbon with abundant microporous structure and electrolyte ions,this paper creatively proposes a divacancy defect building strategy to precisely control the hierarchically pore structure with high specific surface area of 1529 m²g^-1for revealing the regulation mechanism of hierarchical pore structure.In the 6 M KOH electrolyte,the three-dimensional porous carbon not only shows the excellent rate performance,but also delivers a mass specific capacitance of 248 F g^-1.Meanwhile,in the EMIMBF₄ionic liquid,the three-dimensional porous carbon-based supercapacitors not only show the good double-layer capacitance characteristics,but also delivers a mass specific capacitance of 38.2 F g^-1.And the supercapacitors deliver a power density of 61.3 Wh kg^-1at a power density of 875 W kg^-1.