Preparation Of Cellulose/PAN Based Porous Carbon Nanofibers By Electrospinning And Electrochemical Properties

The carbon nanofibers already become the important raw material for the preparation of various structural and functional composite materials,because of the high corrosion resistance,the good fatigue resistance,and more stable chemical properties and so on.However,the porosity of carbon nanofibers prepared by the traditional method is so small,which limits its further development in various fields such as electrochemistry,biology and filter material,etc..Therefore,the improvement of the specific surface area of carbon nanofibers has become a hot research topic.In this paper,we propose a new method to prepare nanofibers based on the covalent bond between polymer and inorganic materials.In this case,PAN/DMF was used as the framework to dope the nanosilica particles and cellulose nanofibers,carbon composite nanofibers were prepared by electrospinning and succedent high temperature calcination.The surface morphology,crystal structure,thermal stability and pore structure of the materials were characterized by scanning electron microscopy,Fourier transform infrared spectroscopy,thermal gravimetric analyzer and N₂ adsorption desorption.The electrical conductivity of the material was tested and analyzed by four probe test method.It is found that the new method is universal,and it can also be applied to other functional polymer materials,and can realize the continuous process of preparation.The specific research contents are as follows:1.Free-standing porous carbon nanofibers were obtained from Polyacrylonitrile/cellulose nanofiber/Silica nanoparticles（PAN/CNCs/SiNPs）by electrospinning and pre oxidation,carbonization,and HF acidification process.The relationship between the ratio of the components and specific surface area was analyzed by using Box-Benhken design method and Response Surface Analysis,which was 70:5:1.The results showed that the highest surface area of 845 m²/g was obtained when composite nanofibers were pre oxidation process with Air at 270℃ for3 h,carbonization process with N₂ at 800℃ for 6h,and HF acidification for 2 h.The study of electrochemical properties showed that the electrical resistivity of carbon based composite nanofibers was 7.14 Ω·cm.2.C/Cu composite nanofibers were prepared by electrospinning PAN/CNCs/SiNPs/Cu（OAc）₂ and subsequent pre oxidation,carbonization and HF acidification process.The experimental results show that when the content of Cu（OAc）₂ is 4%,the specific surface area of the C/Cu composite nanofibers is 987m²/g,which is improved by 17%,compared to the carbon nanofibers.The study of electrochemical performance showed that the electrical resistivity of carbon based composite nanofibers was 6.03 Ω·cm increased by 18%,compared to the carbon nanofibers.3.C/Ni composite nanofibers were prepared by electrospinning PAN/CNCs/SiNPs/Ni（OAc）₂ and subsequent pre oxidation,carbonization and HF acidification process.The experimental results show that when the content of Ni（OAc）₂ is 2%,the specific surface area of the C/Ni composite nanofibers is 916m²/g,which is improved by 8%,compared to the carbon nanofibers.The study of electrochemical performance showed that the electrical resistivity of carbon based composite nanofibers was 5.44 Ω·cm increased by 31%,compared to the carbon nanofibers.