Preparation method of iron phosphate for preparing lithium iron phosphate and iron phosphate

Abstract

The invention discloses a preparation method of iron phosphate for preparing lithium iron phosphate. The preparation method comprises the following steps of: (1) preparing cationic surfactant aqueous solution; (2) preparing soluble iron salt aqueous solution and soluble phosphate aqueous solution of 0.1-5 mol / L respectively; (3) adding the soluble iron salt aqueous solution and the soluble phosphate aqueous solution into the cationic surfactant aqueous solution in sequence at 25-50 DEG C under ultrasonic treatment and stirring according to a molar ratio of Fe: P of 1:0.8-1.2, wherein the speed is less than or equal to 60 ml / min, and the concentration of a cationic surfactant in reaction solution formed after all materials are added is 1-10 g / L; (4) adding ammonia water at 25-50 DEG C under ultrasonic treatment and stirring to adjust the pH of the solution to be 0-3, performing ultrasonic treatment for a time and continuously stirring for 30-180 minutes; and (5) washing the liquid obtained by the step (4) with de-ionized water or absolute ethanol and then drying at 70-90 DEG C to obtain powdery iron phosphate.

Description

technical field [0001] The invention belongs to the field of inorganic materials, and in particular relates to a method for preparing iron phosphate used for preparing lithium iron phosphate and iron phosphate. Background technique [0002] At this stage, energy and environmental problems are becoming more and more serious, the development and use of clean energy is imminent, and the development of electric vehicles is the trend of future development. The large-scale application of green energy such as wind energy, solar energy, and geothermal energy has put forward higher requirements for energy storage devices, especially for the service life of energy storage batteries. [0003] Lithium iron phosphate, the cathode material of lithium-ion batteries, has good safety performance, low price, high thermal stability, good cycle performance, high theoretical capacity (170mAh / g), and high charge and discharge platform (3.4V~3.6V) , no memory effect, environmental friendliness an...

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Problems solved by technology

[0005] The patent application with the publication number CN101891176A discloses a method for preparing iron orthophosphate for lithium-ion battery materials with non-ionic surfactants, but the particle size of the prepared iron orthophosphate is large and uneven (50-300nm), indicating that Simple non-ionic surfactants can not play a good dispersion effect, this method is not suitable for the preparation of lithium iron phosphate precursor iron phosphate

The patent application with the publication number CN10695998A discloses a preparation method for preparing nanoscale iron phosphate. Although the particle size of the prepared iron phosphate is small, the distribution is uneven (10~100nm), and the rotating packed bed reactor used Complicated to use, not suitable for mass production

In the patent application with the publication number CN1021101662A, ferrous oxalate and phosphoric acid are used as raw materials to prepare anhydrous crystalline ferric phosphate. Because of the high temperature treatment at 500°C in the process, the energy consumption is large and the ferric phosphate is easy to grow. The performance of lithium has adverse effects on

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