Lifepo < Sub > 4 < / Sub > Preparation And Its Performance Testing

Peridot structure of LiFePO4is one of the research hotspot of the lithium ion battery anode materials since been found with the Wide raw material sources, low-price, safe, cycle of good performance, Friendly to environment. In this article, we use the high temperature solid phase method to explore the influence of the structure and performance of the product by the different add carbon way, different pretreatment temperature, different organic carbon source and different lithium source. We also study the Li0.99Na0.01FePO4/C which adopped by CMC in the precursor. We analyse the microstructure and the morphology by TG-DSC、XRD、FT-IR、SEM、TEM/SAED/EDS and Raman. Beyond that, we use the charging and discharging tester to analyse the electrochemical performance.We use FeC2O4·2H2O as bivalent iron source and high temperature solid phase method preparing LiFePO4/C composite materials. In the process of preparing the LiFePO4, we mix the materials by two times ball-milling and add organic carbon sources in the raw materials. We can obtain the purer, smaller particles of the LiFePO4/C. With two times ball-milling, and add organic carbon sources each time, we get the better electrochemical performance of LiFePO4/C. In the experiments of exporing different pretreatment temperature, we found that the partical of the LiFePO4/C will grow lagger with the increase of temperature pretreatment. And we get the better electrochemical performance of LiFePO4/C with good electrochemical performance at500℃. We also expore the different orange carbon rouce add in the second ball mill, and get the better electrochemical performance of LiFePO4/C with phenolic resin.We use FeC2O4·2H2O as three pirce iron source and high temperature solid phase method preparing LiFePO4/C composite materials, and expore the different lithium source (Li2CO3, LiF, LiOH, Li2C2O4) on the material properties impacts. With these four kinds of lithium source, we get the LiFePO4/C with more and more impurities, and the bigger particals. We get LiFePO4/C with the better electrochemical performance of LiFePO4/C with lithium source of Li2CO3campare with LiF and Li2C2O4. But we use LiOH as the lithium source preparing LiFePO4/C, it showed excellent electrochemical performance. The specific reason is need further discussion.We use CMC as the doping agent in the precursor to prepare Li0.99Na0.01FePO4/C composite material. We found the average particle size is about300nm, and is looked like spherical. It alse has the perfect carbon-encapsulated layer. And the LiFePO4/C without adopping by CMC, the average particle size is about500nm with the no rules morphology. The carbon-encapsulated layer is also nonuniform. The first discharge specific of Li0.99Na0.01FePO4/C was146mAh·g-1, and the undoped sample was146mAh·g-1.