Study On Microwave Synthesis And Modification Of The Lithium-ion Batteries Cathode Material LiFePO₄

In the modern society with rapid development,particularly in recent,the oil,coal, natural gas and other traditional energy sources are continue mining,resources are depleted,The lithium ion batteries,as a environmentally friendly alternative energy, received universal attention from the people.It become the preferred mobile power with advantages such as high voltage,energy density,long cycle life,self-discharge, no memory effect and good environmental acceptability.Lithium iron phosphate is the new cathode material for lithium-ion batteries,with high theoretical capacity and voltage,good cycle performance,better thermal stability,cheap and environment friendly,it get people's widespread attention.However,due to its crystal structure restrictions,lithium iron phosphate electronic get low conductivity,which is the greatest impediment to its application.In this paper,base on depict the lithium-ion battery and it is research progress in detail,it was investigated to the synthesize and modification about lithium iron phosphate using the microware combining with sol-gel methods,studied the LiFePO₄ structure and electrochemical performance influenced by the synthesize condition, and try to modificate the material by doped,analysis of the structure of the product by X-Ray Diffraction,observe the morphology of the material by Scanning Electron Microscope,the capacity and cycling performance by Galvanostatical charge-discharge testing.This Experiment taking FeC₂O₄·2H₂O,LiNO₃,NH₄H₂PO₄ as raw materials, using metal cation doping for modification,adopt Zn²⁺doped into the Fe site, comparing their performance and the charge-discharge cycle performance.It indicates that the doped LiFePO₄ can get good performance and charge-discharge cycle performance,simultaneity,taking different rate of 1%,3%,5%Zn²⁺doping.The results show that the first discharge capacity of 3%Zn²⁺doping LiFePO₄ are 152 mAh·g^-1(0.11C).Based on doping metal ions can further minish the irreversible loss of capacity and improve the cycle stability,the discharge capacity reach 131 mAh.g^-1after 20 times.