Preparation method of positive electrode material lithium iron phosphate

　　Author ：Iflowpower – Portable Power Station Supplier

Lithium iron phosphate exists in the form of phosphate lithium ore in nature, has an orderly olivine structure. Lithium phosphate chemical molecular formula is: LIMPO4, where lithium is positive; the center metal iron is a positive price; the phosphate is negative three-price, often used as a lithium battery positive material material. The application of lithium iron phosphate batteries are: energy storage equipment, electric tools, light electric vehicles, large electric vehicles, small equipment and mobile power, including lithium iron phosphate with new energy electric vehicles account for 45% of the total amount of phosphite.

Second, lithium iron phosphate as a lithium electrode material compared to other lithium battery positive materials, olivine structure is more secure, environmentally friendly, cheap, long-term, high temperature performance, etc., is the most potent lithium ion One of the battery positive materials. Safety performance is a solid P-O key in high-phosphate crystals, it is difficult to decompose, and it will not be structurally collapsed or generate strong oxides during overcharge and high temperatures.

Circulating life Long lead-acid battery cycle life is around 300 times, service life is between 1 and 1.5 years. And the number of lithium iron phosphate battery can reach more than 2,000, theoretically use life of 7-8 years.

High temperature performance is high-temperature iron-free phosphate thermal peaks up to 350 ° C to 500 ° C, while lithium manganganate and lithium cobaltate is only about 200 ° C. Environmentally friendly lithium iron phosphate battery is generally considered to not contain heavy metals and rare metals, non-toxic, non-polluting, is an absolute green environmental battery. The charge and discharge mechanism of lithium iron phosphate as a positive electrode material is different from other conventional materials, and the charge and discharge of electrochemical reflects the two phases of lithium iron phosphate, the charge and discharge reaction is as follows: charging reaction: Discharge reaction: Charge, Li + From LifePO4, Fe2 + lost an electron into FE3 +; when discharged, Li + embedded in iron phosphite into LifePo4.

The change of Li + occurs in the Lifepo4 / Fepo4 interface, so the charge and discharge curve is very flat, the potential is also more stable, suitable for electrode materials. Third, the preparation of lithium iron phosphate preparation of ingredients with lithium iron phosphate. Some common lithium source, iron source, carbon source, and phosphorus source are as follows: The preparation of lithium iron phosphate powder can affect its performance as a positive material.

There are many methods for the preparation of lithium iron phosphate, such as high temperature solid phase reaction, carbon thermal reduction method, and unminerated hydrothermal method, spray thermal solution, sol - gel method, total precipitation method, etc. 1. High temperature solid phase reaction method high temperature solid phase reaction method is to prepare lithium iron phosphate is the most mature development of the current development and the most widely used method.

After the iron source, lithium source, phosphorus source is mixed with a chemical meter than uniformly mixed, in an inert atmosphere, first sintered 5 to 10 h at a lower temperature (300 ~ 350 ° C), so that the raw material is initially decomposed, then in high temperature ( 600 ~ 800 ° C) Sintering 10 ~ 20h to get olivine type lithium iron phosphate. High temperature solid phase method synthesis of lithium iron phosphate process is simple, preparation conditions are easy to control, the disadvantage is that the crystal size is large, the particle diameter is not easy to control, the distribution is uneven, the shape is also irregular, the product range is poor. 2.

Carbonatic thermal reduction method carbon thermal reduction method is to add carbon sources (starch, sucrose, etc.) in raw material mixing, usually used together with high temperature solid phase, and the carbon source can reduce Fe3 + in high temperature calcination to Fe2 +, Avoid the reaction during the reaction to become Fe3 +, so that the synthesis process is more reasonable, but the reaction time is relatively long, and the control is more stringent. 3.

Spray pyrolysis spray heat solution is an effective means of obtaining uniform particle size and regular shape of lithium iron phosphate powder. The precursor is inseed of a reactor of 450 to 650 ° C with the carrier gas, and lithium iron phosphate is obtained after high temperature reactions. The precursor fog spherical spherical spheroid prepared by spray pyrolysis is high, and the particle size distribution is uniform.

After high temperature reactions, the pneumophosphate is obtained. Lithium iron phosphate sphere is conducive to increasing the specific surface area of ​​the material, increasing the volume ratio energy of the material. 4.

Water heating method is a liquid phase synthesis method, refers to a chemical reaction in a sealed pressure vessel in a sealed pressure vessel, and is chemically reacted by the raw material, washed by filtration, drying after drying. Lithium iron phosphate can be obtained after the high temperature is calcined. Preparation of ferrite in hydrothermal method has the advantages of easy control of crystalline form and particle size, average particle diameter, small particle diameter, simple process, but requires high temperature and high pressure equipment, high cost, complicated process complicated.

In addition to the above method, there is a common precipitation method, a sol-gel method, an oxidative-reduction method, an emulsified drying method, and a microwave sintering method. 4. Summary Although the preparation method of lithium iron phosphate is much more, except for the high temperature solid phase reaction method, most of the laboratory research stage.

With the continuous deepening of phosphate preparation and modification, the industrialization speed of ferrite phosphate is constantly accelerated. To learn the progress of the latest lithium iron-ion battery positive material, please sign up for the 2017 Energy Particle Material Preparation and Testing Technology Seminar on October 16-17! At that time, Professor, the Professor, Hu Guorong, Central South University, will share the report of "Lithium-Ion Battery Positive Code Material Lithium Lithium Lithium Industrialization". Deputy Director of the Institute of Metallurgy and Environment, Central South University, Deputy Director of the Institute of Technology, Department of Advanced Battery, Department of Engineering, China, China Chemistry and Physical Power Association, China Lithium Battery Association, International Power Supply Commission, Lithium Battery Communication Committee.

Mainly engaged in electrochemical theory and application, energy materials and other aspects, and has achieved protruding results in the development and industrialization of lithium-ion battery positive electrode materials. Hold and participate in more than 20 national and provincial-level scientific research projects, including a special project of major industrialization of the National Development and Reform Commission, one of the National Science and Technology Department of 863, is responsible for a national science and technology support plan project, a national torch plan project Items and many key scientific and technological projects in Hunan Province. A protruding results have been achieved in the industrialization of lithium-ion battery positive electrode materials, and successfully realize lithium cobalt organism, lithium manganate and lithium iron phosphate.

About 2017 Energy Granular Material Preparation and Testing Technology Seminar This meeting aims to provide communication platforms for relevant scholars at home and abroad, in the application of energy granules, strengthen industry information exchange, lithium battery, capacitor, fuel cell , Electric car battery technology breakthrough make contributions. Organizer: China Particle Society Energy Granular Materials Committee, China Powdered Network Association Unit: Nuremberg Exhibition (Shanghai) Co., Ltd.

Sponsored units: Kawaguklang (Shanghai) Powder Machinery Co., Ltd., Dandong Baite Instrument Co.

, Ltd. Jiangsu Miyou Powder New Equipment Manufacturing Co., Ltd.

Support Unit: Ningbo Materials Technology and Engineering Institute, Chinese Academy of Sciences, Institute of Process Engineering, Tsinghua University, Institute of Physics, Chinese Academy of Sciences, China Academy of Sciences Dalian Chemical Physics, China Battery Industry Association , China Super Capacitor Industry Alliance, Dongguan Yifu Machinery Technology Co., Ltd., Shijiazhuang Day Powder Equipment Technology Co.

, Ltd., Jiangsu Highway Intelligent Equipment Co., Ltd.

, Linyi County Chasing RMB Co., Ltd., Guangzhou Zhonghuo Intelligent Equipment Co.

, Ltd. , Shenzhen Boyi Chemical Machinery Co., Ltd.

, Malvin Instrument Co., Ltd., Xinxiang Yangli Machinery Co.

, Ltd. The angle of the preparation, examine the advantages and disadvantages of core energy materials such as lithium batteries, sodium batteries, supercapacitors, fuel cells; highlights 3:, for example, new energy particles (such as graphene, carbon nanotubes, ternary lithium electrode, sodium ion battery electrodes, Metal lithium) technology and its application in energy storage and conversion industries; highlights 4: The latest technical achievements of energy granules and industry leaders; highlights five: exhibitions and conferences, lithium electric materials, supercapacitor manufacturing equipment, detection Technology and application one-stop display. Highlight 6: Project docking.

Domestic lithium batteries, lithium-electric materials production enterprises, new project leader, the purchase consultation consultation consultation consultation. .