Carbon Coating Process Of Lithium Iron Phosphate And Electrochemical Performance Of The Research

Olivine-type LiFePO4cathode materials have drawn widespread concern of many scientists in recent years for their advantage on high operating voltage, large capacity, non-toxic, environmentally friendly, safe, stable and low cost. They had great potential in lithium-ion battery. But the intrinsic electronic conductivity and lithium ion diffusion coefficient of pure phase LiFePO4cathode material were very low, which hindered their promotion and application. Optimizing the preparation process and carbon-coated modification were effective means to improve the electrochemical performance of LiFePO4.In this paper, high temperature solid phase method, microwave method, combination of high temperature solid state and microwave method were used separately to prepare LiFePO4cathode materials. Electronic conductivity and lithium-ion diffusion coefficient of LiFePO4were improved by optimizing the preparation process and exploring the adaptive carbon-coated process, characterization testing was used to study the electrochemical properties of the material.1, LiFePO4and LiFePO4/C composite materials were prepared by high temperature solid phase method. The optimum preparation conditions was determined by studying the influence of different lithium source, different sintering temperatures, time and pressure on electrochemical properties, surface morphology and crystal structure of the materials. Different carbon sources, carbon-coated methods and quantity were also discussed on the influence of electrochemical properties, material morphology and tap density, to determine to optimum carbon-coated conditions.2, LiFePO4and LiFePO4/C composite materials were prepared by Microwave method, respectively. Experiments were designed to determine the relationship between microwave power and microwave sintering time. Under certain microwave power, the optimum preparation conditions was determined by studying the influence of different sintering time and sintering methods on electrochemical properties, surface morphology and crystal structure of the materials. The optimum carbon-coated conditions were also determined by discussing different carbon-coated methods and quantity on the influence of electrochemical properties, material morphology and tap density.3, Pure phase LiFePO4and LiFePO4/C composite material were prepared by combination of high temperature solid state and microwave method. The electrochemical performance, surface morphology and crystal structure of the material were studied. The optimum preparation conditions were determined by discussing different carbon-coated methods and carbon-coated quantity on the influence of electrochemical properties, material morphology and tap density.