Lithium-ion Battery Cathode Material Of Lifepo <sub> 4 </ Sub> Synthesis And Modification Of Research

The increasing concerns on energy, environmental and the rapid development of modern science and technology have more demands on batteries. Lithium ion batteries (LIB) are attractive for use in the field of mobile power source with the favorable properties of high voltage, long cycling life, high energy density, non-memory effect and pollution-free. Intensive research is being conducted to further improve the performance of lithium ion batteries and reduce the cost of electrode materials. On the base of reviewing the development of lithium ion battery and its cathode materials in detail, olivine LiFePO4 were chosen as cathode material and their synthesis and modification were studied.The effects of synthesis conditions on physical performance and electrochemical behavior of olivine LiFePO4 were studied. We discussed the effects of temperature, time, dopant and doping amount on the performance of product and optimized synthesis condition through orthogonal experiment.The samples were analyzed by DTA and XRD. The electrochemical performances of olivine LiFePO4 were" enhanced by doping metal ions and coating carbon. The results showed that samples doped magnesium ion exhibited high specific capacity (120 mAh) in doping metal ions samples, and the samples coated sugar exhibited high specific capacity(147 mAh) and good cycling performance in coating carbon samples moreover the final amount of carbon was only 3.06wt%.Olivine LiFePO4 was synthesized by microwave heating for the first time and the reactions could be finished within 30 minutes. The results showed the sugar-coating samples by microwave heating exhibited smaller particles, high specific capacity (124 mAh) and good cycling performance.The kinetics behaviors of olivine LiFePO4 and modified samples were studied by means of cyclic voltarnmetry and electrochemical impedance spectroscopy measurements. it was concluded that themagnitude level of diffusion coefficient in olivine LiFePO4cathode is 10-13 cm2 and diffusion coefficient was affectedby voltage.