PVC-based Carbon Composite Nanofibers And Their Energy Storage Performance

Carbon nanofibers have been used in many fields such as electrode materials, catalyst supports, and gas sensor materials due to their unique structure, high surface area, and physical and chemical properties. Moreover, the new category of carbon composite nanofibers should find applications in a variety of fields. On the other hand, poly(vinyl chloride)(PVC) is one of the five general synthetic resins. Its production amount is second-highest after polyethylene (PE). With the growth of its production and consumption, the number of PVC waste also increases. The carbonization of PVC to prepare carbon nanofibers is an efficacious technique for the resourceful utilization of PVC waste. Therefore, in this paper, some work has been done as follows.(1) To prepare the elecrospinning solution, PVC and NiCl2were dissolved in N,N-dimethylformamide (DMF) with0.1mL1,8-diazabicyclo[5.4.0]undec-7-ene (DBU). The PVC/NiCl2composite nanofibers with a diameter range of80～140nm were fabricated from the obtained solution by the electrospinning technique. The as-prepared composite nanofibers were exposed to iodine vapor for48h prior to the carbonization in nitrogen at1000℃. The C/Ni composite nanofibers containing graphitic nanoparticles were synthesized. The structure of the C/Ni composite nanofibers was characterized by SEM, TEM, Raman, XRD. The suggested growth mechanism of carbon nanofibers containing graphitic nanoparticles was proposed. The results show that the C/Ni composite nanofibers (with a diameter range of50～100nm) consist of both amorphous carbon and a well-grown graphite layered sphere with a diameter of35nm. It is also clear that the iodine treatment is essential for retaining a fibrous shape during the carbonization, and the addition of NiCl2is beneficial to the growth of the carbon yield and graphitization. The hydrogen storage capacity of the C/Ni composite nanofibers is determined to be0.30wt%under95bar at25℃.(2) To prepare the elecrospinning solution, PVC and NiCl2were dissolved in DMF with0.1mL DBU. The PVC/NiCl2composite nanofibers with a diameter range of80～140nm were fabricated from the obtained solution by the electrospinning technique. The as-prepared composite nanofibers were immersed in a6.25mol/L NaOH solution for24h, stabilized at260℃in air for3h, and carbonized at1000℃in nitrogen. C/NiO/Ni composite nanofibers were synthesized and characterized by SEM, TGA, XRD. The effects of NaOH concentration and the addition of NiCl2on the preparation of C/NiO/Ni composite nanofibers were also investigated. The results show the addition of NiCl2and NaOH concentration are essential for retaining a fibrous shape during the carbonization.(3) To prepare the elecrospinning solution, PVC and LaCl2were dissolved in DMF with0.1mL (DBU). The PVC/LaCl2composite nanofibers with a diameter range of30～140nm were fabricated from the obtained solution by the electrospinning technique. The as-prepared composite nanofibers were immersed in a6.25mol/L NaOH solution for24h, stabilized at260℃in air for3h, and carbonized at750℃in nitrogen. C/LaOCl composite nanofibers were synthesized. The CO2adsorptive capacity of the C/LaOCl composite nanofibers was investigated. The suggested mechanism of the CO2desorption of C/LaOCl composite nanofibers at low temperatures was proposed. The results show the CO2adsorptive capacity of C/LaOCl composite nanofibers (with the addition of16wt%LaCl3) is determined to be0.32mL/g at50℃. The addition of LaCl3is beneficial to the CO2adsorptive capacity of PVC-based carbon nanofibers.(4) To prepare the elecrospinning solution, PVC was dissolved in DMF with0.1mL DBU. The PVC nanofibers were fabricated from the obtained solution by the electrospinning technique. The as-prepared composite nanofibers were immersed in a6.25mol/L NaOH solution for24h, stabilized at260℃in air for3h, and carbonized at600℃in nitrogen. The obtained carbon nanofibers were dispersed in0.025mol/L FeCl3solution by ultrasonication for1h. The mixture was transferred into a Teflon-lined stainless steel autoclave, maintained at180℃for8h, and then calcined at500℃in nitrogen. C/Fe2O3composite nanofibers were synthesized and characterized by SEM, Raman, XRD, TEM, TGA. The electrochemical performance of the C/Fe2O3composite nanofibers was investigated. The results show that the carbon nanofibers (with a diameter range of50～130nm) are handcuffed with Fe2O3rings (with a diameter range of250～400nm) in the C/Fe2O3composite nanofibers (with the addition of22.5mg PVC-based carbon nanofibers). The composite electrode exhibits a stable specific capacity of over600mAh g-1after50cycles at50mA g-1.