The Study Of Several Organic Anode Materials For Lithium Ion Battery

Lithium-ion batteries are widely used in portable electronics and have great potential in new energy vehicles,smart grids and other fields.At present,the electrode materials of lithium ion batteries are mostly inorganic compounds,which have the disadvantages of strong resource dependence,large environmental destruction and difficult recycling.Different from the inorganic electrode materials,the organic materials have the unique advantages of rich sources,environmental friendliness,convenient recycling,structural diversity,flexibility and processability,and are the new research object of the new generation of"green power".Organic electrode materials have a series of disadvantages,such as low conductivity,limited redox sites,and easy to be dissolved in organic electrolyte,which seriously affect the energy density,magnification performance and cycle life of battery devices.In view of the above problems of organic electrode materials,we tried to carry out the following work:1.Morphological control and surface modification are common methods to change polymer properties.In this paper,polyacrylonitrile/polyethylene glycol nanofibers were prepared by electrospinning technology,and porous polymer nanofibers were further prepared by the atmosphere regulation of low-temperature heat treatment.Electrochemical studies have shown that the fiber materials treated with air atmosphere have high electrochemical energy storage performance and good cycling stability(at the current density of 50 mA/g,its capacity remains at 418 mAh/g after 100 cycles).Spectral studies show that the lithium storage performance of nanofibers is mainly due to the abundant C=O and C=N groups on the surface.Microstructure analysis showed that the porous structure of the nanofibers shortened the diffusion distance between Li~+and electrons,provided a larger electrode/electrolyte interface for charge transfer reaction,and further improved the reversible capacity and cycling stability of the materials.This work provides new ideas for the functionalization and morphological design of organic polymers.2.Organic compounds have disadvantages such as limited redox sites(limited lithium storage capacity)and solubility in electrolyte(reduced cycling stability).In view of this,we try to use the coordination ability of transition metal ions with organic molecules to improve the energy storage performance of organic compounds.Taking natural organic folic acid as an example,a series of folic acid metal complexes(FA-MCs,M=Fe,Co,Ni)were prepared with the participation of metal ions and applied to the electrode materials of lithium ion batteries.The prepared metal organic coordination has the synergistic effect of multi-electron transfer and enhances the storage capacity of lithium ions.In addition,the formation of metal organic complexes effectively inhibits the dissolution of folic acid in organic electrolytes and further improves the cycling stability.Among them,FA-CoC maintains a capacity of220 mAh/g after 100 cycles when the current density is 80 mA/g.This work not only promoted the application of the assembly strategy,but also proposed an effective method to improve the organization performance.