Preparation method of lithium iron phosphate and application thereof

Abstract

The invention relates to the technical field of preparation of lithium ion battery positive electrode materials, in particular to a preparation method of lithium iron phosphate and an application thereof. The preparation method comprises the following steps: mixing a ferrous sulfate solution and a phosphate solution, carrying out a synthetic reaction, aging the solution after the synthetic reaction, carrying out solid-liquid separation on the aged solution, washing a filter cake, drying, calcining, crushing, screening, and removing iron to obtain a mixture of anhydrous iron phosphate and ferric oxide; sequentially adding the mixture, Li3PO4 and H3PO4 into a glucose solution to obtain mixed slurry, grinding the mixed slurry to obtain nanoscale mixed slurry, and drying the nanoscale mixed slurry to obtain a mixed powder material; and roasting the mixed powder material at the temperature of 700-800 DEG C in a heat preservation manner, and crushing to obtain the lithium iron phosphate. According to the method, one-step synthesis of anhydrous iron phosphate in an inorganic system is realized, the obtained anhydrous iron phosphate is good in dispersity and uniform in particle size distribution, and back-end lithium iron phosphate process control and performance parameter optimization are facilitated.

Description

Technical field [0001] The present invention relates to the preparation of a lithium ion battery positive electrode material, and in particular, there is a method and use of a lithium iron phosphate. Background technique [0002] With the increasing depletion of petroleum resources, the development of electric vehicles is imperative. At present, the most critical technology of electric vehicles is to develop goods, safe and environmentally friendly secondary batteries. Lithium-ion batteries are recognized as the best candidate for electric vehicle power batteries due to high voltage, high ratio energy and high power. For lithium-ion batteries, the positive electrode material is a key factor in determining its electrochemical properties, safety performance, energy density, and price costs. 1997 Goodenough, etc. First report olivine structure Lifepo 4 Reverse lithium - dethium characteristics. Since it has the advantages of safe performance, long cycle life, the source of raw mater...

AI Technical Summary

Problems solved by technology

[0005] First, in the production process of anhydrous ferric phosphate, environmental protection pressure is high, and the cost of wastewater treatment is high. According to statistics, nearly 70 tons of wastewater is produced per ton of ferric phosphate, which contains some pollution factors such as sulfate, phosphate, ammonium, and iron ions. , the processing volume is large, and the processing cost is high

[0006] Second, the production process of anhydrous ferric phosphate is long, and the process includes the synthesis of ferric phosphate dihydrate-washing-drying-high temperature calcination and dehydration, etc. The equipment investment is large, the labor cost and energy consumption are high, and the final anhydrous ferric phosphate product The cost remains high, which leads to the high cost of lithium iron phosphate

[0007] Third, the production of lithium iron phosphate using lithium carbonate is expensive, and the production process consumes a lot of energy and costs high

Images