Preparation And Electrochemical Performance Of Vanadium-based Materials For Secondary Battery Cathodes

Energy storage has become the research focus of contemporary new energy technology with increasingly more attention paid to the development and utilization of new energy since the development of economy. Undoubtedly, batteries are the representative of the energy storage equipment, especially lithium ion battery for its light quality, high specific energy, long life, safety and reliable environmental advantages meeting the requirements of the energy storage equipment, which is now widely used in electronic equipment and vehicles. So it is vital and urgent to develop better electrode materials. China has the rich vanadium resources known as the world’s fifth largest vanadium resource country. And vanadium-base materials with layered or tunnel structure are more suitable for accommodating a large number of lithium ions and sodium ions secondary batteries cathode materials. The purposes of this paper are to synthesize high crystallinity, high purity, less aggregation and different structure based on vanadium secondary batteries cathode material controllably with hydrothermal synthesis or sol-gel methods according to the characteristic of materials, and study electrochemical behavior of the second batteries for a preliminary exploration in theory. The main points are summarized briefly as follows:（1） We have successfully developed a facile one-pot process for the synthesis of vanadium-based layer transition metal sulfides VS2 and modified with graphene to synthesize VS2/graphene composites in the presence of cetyltrimethylammonium bromide without further heat treatment. Furthermore, the effect of additives on the morphology of VS2 was studied. Its preliminary study on the mechanism of lithiation/delithiation through the test of electrochemical performance combined with a series characterizations of ex situ XRD, SEM, TEM, etc. Results show that the composite material exhibits excellent rate and cycle performances, which make it be a potential lithium ion battery cathode material.（2）With a simple sol-gel method of introducing yeast cells, we synthesized Na3V2（PO4）₃ with NASION structure sodium cathode materials, studied the influence of temperature and cells addition quantity on electrochemical performance. Using X-ray diffraction（XRD）, SEM, TEM to characterize the structure and morphology, galvanostatic charging/discharging, cyclic voltammetry（CV） and electrochemical impedance（EIS） test to investigate electrochemical properties of the materials.