Application Of Vanadium And Silicon Composite Materials As Anode Materials For Lithium Ion Batteries

Lithium ion battery has been widely used in portable electronic products, and will also has broad application prospects in electric cars and scale energy storage area. However, commercial lithium ion batteries which are using flammable organic electrolyte, has not only stringent assembly conditions, high cost, but also the existence of a large security risk, which seriously restrict the application and promotion of lithium-ion batteries. Aqueous system lithium ion battery overcomes the shortcomings of the traditional system of organic electrolyte battery?s kinds of shortcoming, such as expensive cost, toxic, flammable, low ionic conductivity and high cost advantages, that makes it one of the most potential green energies except of wind and solar energy. At present, there are two main types of negative electrode materials, such as carbon materials and non-carbon materials. Instead of graphite, due to its wide range of sources, affordable, stable performance graphite anode material has occupied the dominant position, but on the other side, its defects of poor performance on high rate discharge makes it necessary to develop more high circulation rate of anode materials.In this paper, the application of the electrode material V₂O₅ in the application of Li ion battery in aqueous system is studied. The work mainly includes the heat treatment of V₂O₅ and, and the interaction of SiO₂ with H₂C₂O₄ and the other methods to improve the charge and discharge capacity and stability of the V₂O₅ as the cathode material of the lithium ion. And by XRD（X-ray diffraction）, SEM（scanning electron microscope）, BET（Brunauer Emmett Teller） and other means of material phase structure, surface morphology, physical characterization, using constant current charge and discharge and CV（cyclic voltammetry） technology in Li2SO4 aqueous solution of charge discharge capacity, steady qualitative and oxygen reduction reaction was studied by electrochemical analysis.Working as following:1.Vanadium pentoxide and silica prepared by heat treatment of the V₂O₅-SiO₂, and by XRD, SEM, BET and N₂ structure and morphology were characterized by their absorption desorption. By CV and constant current charge and discharge tests show that the material in aqueous as the electrolyte of lithium ion batteries which deintercalation of lithium ions are reversible, the discharge capacity is 199 mAh g-1, greater than any other in aqueous electrolyte having a valence of vanadium oxide multiple discharge capacity（less than 110 mAh g-1）. In addition, after 100 cycles of charge and discharge capacity even V₂O₅-SiO₂ maintained at 12%, so that the material has a better cycling stability than other vanadium oxides.2.The SiO₂ coated V-C spheres were calcined in air and N₂. The structure and morphology of were characterized by XRD, SEM, and BET. By CV and constant current charge discharge shows that, prepared by the method of particle charge and discharge cycle after 100 cycles the efficiency almost keep to 98%, also discharge capacity also reached 100 mAh g-1. Thus its stability has been greatly improved.3.Pyrrole continue coat the second part of the prepared samples,by XRD, SEM, TEM and BET were used to characterize the structure and morphology. The CV and constant current charge discharge show that the coated V₂O₅ has better stability and cycling, after 100 cycles, the discharge capacity keep to 80%, and its Lulun efficiency is close to 100%. Therefore, the material has a more stable cycle performance than other vanadium oxides.