What are the manufacturing methods for lithium iron phosphate?

Lithium iron phosphate manufacturing method 1. High temperature solid phase method High temperature solid phase method is an important method for lithium iron phosphate battery processing, and it is also the most mature method. Usually iron salt (such as ferrous oxalate FeC2042H, 0), phosphate (such as diammonium hydrogen phosphate (NHA). HPOA) and lithium salt (such as lithium carbonate Li, C03) as raw materials, after sufficient mixing according to the stoichiometric ratio , In an inert atmosphere, it is pre-analyzed at a lower temperature, then calcined at a high temperature, and made by grinding. >Advantages: The high-temperature solid-phase synthesis method has simple operation and process route design, easy control of process parameters, stable properties of the prepared materials, and easy realization of industrialized large-scale processing. >Disadvantages: ①The powder raw materials need to be milled and mixed for a long time, and the average degree of mixing is limited, and the doping modification effect is poor; ②Requires a higher thermal solution temperature and a longer thermal solution time, and consumes a lot of energy; ③Product There are big differences in composition, structure, particle size distribution, etc., and Fe impurity phases are easy to appear; ④The electrochemical performance of the material is not easy to control; ⑤The ferrous oxalate used is relatively expensive, and the material manufacturing cost is relatively high; a large amount of inertness is required during the reaction The cost of protective gas and inert gas is relatively high; ⑥Ammonia, water, and carbon dioxide will appear in the sintering process, and ammonium bicarbonate crystal particles will appear during the cooling process in the furnace, which will cause product pollution. In addition, the emergence of ammonia is not conducive to environmental protection, and additional exhaust gas solutions should be added. 2. Carbothermal reduction method The carbothermic reduction method is also one of the high-temperature solid-phase methods. It is a relatively easy to industrial synthesis method. Most of them use lithium dihydrogen phosphate (LiH, PO,) and iron trioxide (Fe. 0. ) Or ferroferric oxide and sucrose as raw materials, evenly mixed, roasted under the protection of high temperature soft argon or nitrogen, carbon reduces ferric iron to divalent iron, that is, lithium iron phosphate is synthesized by carbothermal reduction method. >Advantages: The oxidation reaction that may be triggered during the mixing of raw materials is processed, making the synthesis process more reasonable and improving the conductivity of the material. > Disadvantages: The reaction time is relatively long, the temperature is difficult to control, and the control conditions required for product consistency are more stringent, and it is difficult to adapt to industrial processing. 3. Hydrothermal synthesis method The hydrothermal synthesis method belongs to the field of wet method. It uses soluble ferrous salt, lithium salt and phosphoric acid as raw materials to directly synthesize LiFePO4 under hydrothermal conditions. Because the solubility of oxygen in the hydrothermal system is very small , The synthesis of hydrothermal system LiFeP04 provides an excellent inert environment. >Advantages: The hydrothermal method can prepare ultra-fine particles in the liquid phase, and the raw materials can be mixed at the molecular level. It has the advantages of average phase, small powder particle size and easy operation, and has the advantages of easy mass production, good product batch stability, and low cost and easy availability of raw materials. At the same time, do not inert atmosphere during processing. > Disadvantages: The structure of the product prepared by the hydrothermal synthesis method often has iron dislocation, which generates metastable FePO. , Which affects the chemical and electrochemical properties of the product. At the same time, there are also shortcomings such as uneven particle size, impure phases, large equipment investment (high temperature and high pressure reactor design and manufacture are difficult, and the cost is high) or the process is more complicated. Disclaimer: Some pictures and content of articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous: BMS lithium battery protection board and BMS battery management system function analysis