Preparation of Multichannel Carbon Nanofibers and Their Application as Supercapacitor
In order to develop cost-effective and high-performance electrode materials for aqueous electrolyte supercapacitors,this study used polyacrylonitrile(PAN),lignin,and polystyrene(PS)as precursors to prepare low-cost multi-channel carbon nanofibers(CNFs)via electrospinning.The PAN/PS/lignin carbon nanofibers(PPLCNFs)were further pre-oxidized and carbonized.The samples with different addition amounts of 0 g,0.5 g,0.75 g,and 1.0 g were labeled as PPLCNFs-0g,PPLCNFs-0.5g,PPLCNFs-0.75g,and PPLCNFs-1.0g,respectively.The microstructure,surface chemical properties,and pore structure of the PPLCNFs materials were analyzed using scanning electron microscope(SEM),transmission electron microscopy(TEM),X-ray diffraction(XRD),Raman spectroscopy,X-ray photoelectron spectroscopy(XPS),and N2 adsorption/desorption isotherms.The electrochemical properties of the materials were evaluated using three-electrode system and symmetric supercapacitor testing.The results showed that the addition of lignin increased the oxygen-containing functional groups,the addition of PS promoted the formation of multiple channels and porous structures in the carbon nanofibers,increasing the specific surface area of the materials.Among the carbon nanofiber samples with different PS addition amounts,PPLCNFs-0.75g exhibited the most favorable structural characteristics and electrochemical performance.It had a lotus root-shaped cross-section,multiple internal channels with small diameters,a high specific surface area(SBET)of 412 m2/g,and a pore volume of 0.24 cm3/g.In the three-electrode system,PPLCNFs-0.75g showed a high specific capacitance of 276 F/g at a current density of 0.5 A/g.When the current density increased to 100 A/g,the specific capacitance retention rate was 53.7%,which was significantly higher than that of the other samples.The symmetric supercapacitor assembled with PPLCNFs-0.75g as the electrode exhibited good energy storage characteristics and cycling stability.At a current density of 0.5 A/g,the specific capacitance was 186 F/g.When the current density increased to 100 A/g,the capacitance retention rate was 52.6%.After 10 000 cycles at a current density of 1 A/g,the capacitance retention rate and coulombic efficiency were99.8%and99.6%,respectively.
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