A kind of ferrous ammonium phosphate, its preparation method and application

Abstract

The invention provides a ferrous ammonium phosphate, its preparation method and application, the general formula of ferrous ammonium phosphate is: NH 4 Fe x m (1‑x) PO 4 , wherein x=greater than 0 and less than or equal to 1; M is selected from one or more of V, K, Co, Mn, Zn, Mg, Ni, Al, Ti, Nb, Zr and Cu. The invention also discloses a method for preparing lithium iron phosphate from ferrous ammonium phosphate, which includes the following steps: mixing ferrous salt, phosphorus source and ammonia water, adjusting the pH of the reaction system to 6-7, and reacting to generate ferrous ammonium phosphate; the ferrous The molar ratio of the salt to the phosphorus source is 0.95-1.03:0.95-1.03; the ammonium ferrous phosphate is reduced and calcined at a high temperature under the protection of an inert atmosphere to obtain ferrous pyrophosphate; the ferrous pyrophosphate is mixed with lithium salt and carbon source, Crushing, ball milling; calcining, carbon coating, and synthesis to obtain lithium iron phosphate. The production process of the invention is simple, the production precision is low, and the preparation and doping are easy.

Description

technical field [0001] The present invention relates to the preparation technology of lithium iron phosphate, in particular to a kind of ferrous ammonium phosphate, its preparation method and use. Background technique [0002] At present, lithium iron phosphate is mostly prepared by the iron phosphate method. The iron phosphate method uses the mixed ball milling of iron phosphate and lithium carbonate, and uses the carbon coating produced by the high temperature carbonization of the carbon source to reduce ferric iron to divalent iron at high temperature. Lithium iron phosphate is formed. However, the performance of lithium iron phosphate prepared by this method depends heavily on the quality of the raw material iron phosphate, including its water content, iron-to-phosphorus ratio, morphology and particle size, etc., while the iron phosphate prepared by the precipitation method on the market is difficult to obtain in batches. This is one of the reasons for the poor stabilit...

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Problems solved by technology

[0003] The object of the present invention is to propose a ferrous ammonium phosphate, which has a stable iron-phosphorus ratio and lattice structure, and can It is used for batch and stable production of lithium iron phosphate, and the ammonium ferrous phosphate of the present invention introduces doping elements into its crystal structure, which is beneficial to the uniformity of doping, and has obvious effects on the uniformity of doping and related properties of lithium iron phosphate. promotion

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