Spherical basic ammonium ferric phosphate powder with large specific surface area and preparation method thereof

Abstract

The invention discloses spherical basic ammonium ferric phosphate powder with a large specific surface area and a preparation method. The method comprises the following steps of: dripping 1 to 2 mol / L tervalent iron salt water solution which does not contain sulfate radicals and choride ions and phosphoric acid or soluble phosphate water solution according to the Fe-to-P molar ratio of 1:(1.1 to 1.6) into a container with stirring at the temperature of between 30 and 80 DEG C; after dripping, adding ammonia water to ensure that the pH is 0.1 to 5 to obtain amorphous basic ammonium ferric phosphate slurry; aging the slurry at the temperature of between 50 and 90 DEG C for 4 to 10 hours; filtering, washing by using deionized water until the filtrate is neutral; and drying a filter cake at the temperature of between 60 and 120 DEG C for 4 to 8 hours to obtain the spherical basic ammonium ferric phosphate powder. The product is petal shaped spherical particles which are dispersed well, particles consist of a large amount of nano sheets, and have uniform sizes; the average grain size of the particles is 1 to 1 mu m; the specific surface area is 80 to 110m<2> / g; and the tap density is more than 0.9g / cm<3>. The process is reasonable and simple, and the product is suitable for large-scale production of electrode materials.

Description

technical field [0001] The invention belongs to the field of compounds containing metal iron ions, nonmetal ammonium and phosphoric acid particles in inorganic chemistry, and relates to a preparation method of basic ferric ammonium phosphate. At the same time, it involves the preparation technology of lithium-ion battery cathode materials. Background technique [0002] With the depletion of petroleum resources and the increasingly serious environmental pollution caused by automobile exhaust, the development and application of electric vehicles (EV) or hybrid electric vehicles (HEV) and corresponding power sources have been developed rapidly. Among them, lithium-ion secondary battery has the advantages of high volume energy ratio and weight energy ratio, high voltage, low self-discharge rate, no memory effect, long cycle life, etc., and has absolute advantages as EV and HEV power energy. [0003] The structure and properties of electrode materials are one of the important fa...

AI Technical Summary

Problems solved by technology

On the one hand, if the particle size of the raw material is too large, the specific surface area of ​​the particle will be small, thereby reducing the effective reaction area, and lengthening the ion diffusion path, making the solid-state reaction difficult

On the other hand, if the particle size of the raw material is too small, the tap density of the raw material is generally low, so that the tap density of the finally obtained lithium iron phosphate product is relatively low, which ultimately affects the electrochemical performance of the battery.

[0006] At present, there is still a lack of research and reports on the morphology control technology of iron phosphate raw materials and the influence of raw material morphology on the performance of the reaction product lithium iron phosphate

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