Study On The Technology For Synthesis Ferrous Phosphate And Lithium Iron Phosphate And On Their Electrochemical Properties

Olivine lithium iron phosphate of lithium-ion battery material has a higher theoretical capacity for 170mAh.g-1. The discharge voltage of Iron phosphate battery is about 3.4V.Lithium ions deintercalation in the charge-discharge process has little effect on the crystal structure.And the iron which is considered one of the most application development value of the lithium-iron battery cathode is rich in natural resources,cheap, no pollution to the environment, good thermal stability.There are many preparation method of the olivine structure Fe3 (PO4) 2·8 H2O. From the iron source valence difference, it is divided into:three price iron source method (such as FePO4) or bivalent iron source method (such as FeSO4 and FeC2O4). Through the chemical experiment, we find the better method of the preparation Fe3 (PO4) 2·8 H2O process. In this paper,we use FeSO4·7H2O as iron sources to discusses the preparation method of Fe3(PO4)2·8H2O.Because it is cheaper and can be easily prepared in industry,so with FeSO·7H20 as a source of iron, Na2HPO4 as the phosphorus source and CH3COONa-3H2O,we can synthesis Fe3(PO4)2·8H2O. We study the influences about the solution pH value,temperature,string on the preparation of Fe3 (PO4)2·8 H2O. The results show that,when the pH value of the solution is between 5.00 and 5.50, and reaction temperature is 20℃or so, vacuum drying temperature is about 70℃, we can get higher purity of Fe3 (PO4)2·8 H2O. we also find thatmixing speed affect the particle size and morphology samples.With the home-made eight-water ferrous phosphate and lithium phosphate, conductive agent, etc,we can prepare the lithium iron phosphate by high-temperature solid phase synthesis. In this paper, I will explore the electrochemical proportions of charge of the lithium iron phosphate which is made by the lithium source,iron source, in a different ratio, with using XRD,SEM and the electrochemical test on samples for structural characterization and performance testing. The result show that the discharge capacity and cycle performance would be better, when the lithium source,iron source is in the ratio of 1:0.9.The sample discharge platform is 3.38V and the initial discharge capacity is about 138mAh/g.Compared with lithium iron phosphate which is made by ferrous oxalate, lithium carbonate, phosphate ammonium dihydrogen with the traditional methods, lithium iron phosphate composed with homemade eight water iron phosphate and lithium phosphate would be better in the field of discharge capacity and cycling performance. And I will make a preliminary study on doped lithium iron phosphate in this paper.Before studying on lithium ion batteries material, cooperation with a high polymer chemical, we processing acetic acid wastewater during the production process. Acetic acid extracted from the industrial waste water not only reduce environmental pollution,but also can take advantage of the recovery of acetic.It not only has an economic effect,but also can protect the environment. In this study,as an opportunity to deal with wastewater which emissions from Henan Polymer Co. Ltd.Extraction with acetic acid solution as an object tributyl phosphate(TBP) as a complexing agent, kerosene as diluent. Conducted a mixed solvent extraction equilibrium experimental studies. Measured the concentration of acetic acid, complexing agent concentration, diluent and different concentration of complexing agent ratio on the extraction rate.. And the molar ratio of TBP extraction of oxalic acid are disussed. By studying the extractant ratio with dilute acetic suitable for the production of acetic acid in double hemp waste extraction,...