Flaky iron phosphate, and preparation method and application thereof

A technology of iron phosphate and flakes, which is applied in the field of flake iron phosphate and its preparation, can solve the problems of reducing production efficiency, agglomeration, and reduction of compaction density, etc., so as to avoid the formation of new crystal nuclei and have strong process controllability , the effect of moderate particle size distribution

CN110357057AActive Publication Date: 2019-10-22HUNAN YACHENG NEW MATERIAL CO LTD
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Publication Date
2019-10-22

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Abstract

The invention discloses flaky iron phosphate, and a preparation method and application thereof. The microscopic morphology of the flaky iron phosphate is a primary particle in a sheet shape with a thickness of 10 to 50 nm, a length of 100 nm to 3 [mu]m and a width of 100 nm to 3 [mu]m. The preparation method comprises the following steps of: weighing a ferrous ion solution and adding phosphoric acid and a crystal modifier; weighing a phosphorus salt solution and adding an oxidizing agent; carrying out mixing to obtain a mixed solution C, controlling the pH value of the mixed solution C to be 1.5-2.2, and carrying out a reaction to obtain pale yellow iron phosphate slurry; converting the iron phosphate slurry into white or pink-white iron phosphate slurry containing crystal forms under theconditions of stirring and heating, reducing a stirring speed by 20%-50% after the completion of the conversion, and carrying out ageing and heat preservation; performing solid-liquid separation, andcollecting a solid portion to obtain a crystalline iron phosphate precipitate; and washing the precipitate and then performing calcination to obtain the flaky iron phosphate. The iron phosphate of theinvention can be used for preparing lithium iron phosphate with high compaction density.
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Description

technical field

[0001] The invention relates to the field of new energy technology, in particular to a sheet-shaped iron phosphate and its preparation method and application. Background technique

[0002] At present, lithium iron phosphate electrode materials have entered the stage of rapid industrialization and application promotion. Power and energy storage batteries made of lithium iron phosphate as the positive electrode also show good safety and cycle performance, and their application scale is gradually expanding. However, Future energy demands put forward higher energy density requirements for lithium iron phosphate power and energy storage batteries.

[0003] As the precursor of lithium iron phosphate, the morphology and particle size distribution of iron phosphate have a great influence on the compaction density of lithium iron phosphate cathode. Therefore, it is of high application value to study the preparation of iron phosphate with controllable morphology. At p...

Examples

Embodiment 1

[0039] Embodiment 1 of the present invention is: a kind of preparation method that is used for preparing sheet-like anhydrous ferric phosphate for high compacted density lithium iron phosphate, comprises the following steps:

[0040] (1) Add 207.5 g of phosphoric acid (w%=85%) and 3.02 g of anhydrous citric acid to 4 L of ferrous sulfate solution with a concentration of 1 mol / L to obtain mixed solution A.

[0041] (2) Add 247.27 g of hydrogen peroxide (w%=27.5%) to 4 L of sodium dihydrogen phosphate ammonium solution with a concentration of 0.85 mol / L to obtain mixed solution B.

[0042] (3) When the reaction speed is 300r / min and the stirring rate is 300r / min, the mixed solution B is uniformly added to the mixed A in 60min, and then the sodium hydroxide solution is added to adjust the pH value of the solution to 1.5. After stirring for 5min, heat to At 88°C, the precipitate turns from light yellow to pink and white, reduce the reaction speed to 150r / min, age and keep warm for...

Embodiment 2

[0044] Embodiment 2 of the present invention is: a kind of preparation method that is used for preparing sheet-like anhydrous ferric phosphate for high compacted density lithium iron phosphate, comprises the following steps:

[0045] (1) Add 1210.6 g of phosphoric acid (w%=85%) and 10.08 g of anhydrous sodium citrate to 20 L of ferrous sulfate solution with a concentration of 1.5 mol / L to obtain mixed solution A.

[0046](2) Add 1854.6 g of hydrogen peroxide (w%=27.5%) to 20 L of potassium dihydrogen phosphate solution with a concentration of 1.125 mol / L to obtain mixed solution B.

[0047] (3) At a stirring speed of 280r / min, uniformly add the mixed solution B to the mixing A within 90min, then add ammonia water to adjust the pH value of the solution to 1.8, stir and react for 10min, then heat to 92°C, The precipitate turns from light yellow to pink and white, reduce the reaction speed to 200r / min, age and keep warm for 6h.

[0048] (4) Separating the iron phosphate slurry f...

Embodiment 3

[0049] Embodiment 3 of the present invention is: a kind of preparation method that is used for preparing flake anhydrous ferric phosphate for high compacted density lithium iron phosphate, comprises the following steps:

[0050] (1) Add 103.71Kg of phosphoric acid (w%=85%) and 3.36Kg of anhydrous ammonium citrate to 2000L of ferrous sulfate solution with a concentration of 1.5mol / L to obtain mixed solution A.

[0051] (2) Add 185.46 Kg of hydrogen peroxide (w%=27.5%) to 2000 L of ammonium dihydrogen phosphate solution with a concentration of 1.5 mol / L to obtain mixed solution B.

[0052] (3) At a stirring speed of 60r / min, the mixed solution B is evenly added to the mixed solution A within 70 minutes, then ammonia water is added to adjust the pH value of the solution to 2.2, and after stirring for 12 minutes, heat to 100°C. The precipitate turns from light yellow to pink and white, reduce the reaction speed to 48r / min, age and keep warm for 3.5h.

[0053] (4) Separating the i...