Preparation And Properties Of Transition Metal Oxide/carbon Nanofiber Material

Electrospinning nanofibers are one-dimensional nanomaterials with large specific surface area,high porosity,and easy to prepare.They have important development prospects in oil-water separation and lithium ion batteries.Transition metal oxides and their nanocomposites are widely used in fields such as optics,electricity,magnetism,catalysis,batteries and sensing due to their special semiconductor properties,photoelectric effects,piezoelectric effects and electromagnetic effects.This paper mainly studied the application of layered TiO2 nanorod arrays/carbon nanofiber membranes in emulsion oil-water separation and CuO/carbon nanofiber composites in lithium ion batteries:1.A flexible carbon nanofiber membrane was prepared by electrospinning combined with high temperature carbonization,and TiO2 nanorod array was further grown on the surface of the carbon nanofiber by a hydrothermal method.The pore size between the arrays was between several nanometers to several tens nanometers,which is a typical mesoporous material.The TiO2 nanorod array/carbon nanofibers has super-hydrophilic and underwater super-oleophobic properties by ultraviolet radiation and can effectively separate the surfactant-stabilized oil-water emulsion.The microscopic morphology of the fiber membrane was observed by scanning electron microscopy(SEM)and the effects of different TBOT addition amounts,thydrothermal times,hydrothermal temperatures and acid concentrations on the morphology of the fiber membrane were investigated.XRD,BET and contact angle tests were used to characterize the structure and wetting properties of the fibrer membrane.The experimental results of the emulsion oil-water separation verified its excellent separation capability:The separation efficiency of the fiber membrane to the oil-water emulsion can reach over 99%.In addition,the TiO2 nanorod array/carbon nanofiber membrane has strong corrosion resistance and high temperature resistance,and can maintain its original morphology and separation capability after 8 cycles,has good cycle performance.2.CuO/carbon nanofiber composites were prepared by electrospinning and subsequent high temperature carbonization and high temperature oxidation.CuO is environment-friendly,easy to prepare and has a high theoretical capacity,but its volume expansion as a negative electrode material for lithium ion batteries is severe,so that the cycle stability and rate performance are poor.In this experiment,carbon was used as a supporter to stabilize CuO and reduce the collapse of the material structure caused by the volume change of CuO in charge and discharge process.At the same time,the addition of carbon can increase the electronic conductivity of the composite.the diameter of the CuO particle is reduced by inserting carbon nanofibers,smaller particle diameter helps to reduce the ion transmission path,so that the rate performance of the material has improved.The effects of different solid content,different content of cupric chloride dehydrate and different carbonization time on morphology and structure of the composites were investigated by SEM,TEM,XRD and Raman spectroscopy.The results showed that the fiber diameter increased with the increase of solid content,and the increase of both CuCl2 2H2O content and carbonization time will increase the diameter of CuO particles.Subsequently,we assembled CuO/carbon nanofibers into half-cells and tested the electrochemical properties of composites with different CuO contents.The test results show that the composite has good cycle stability and rate performance compared to pure CuO.