Preparation method of high-tap-density iron phosphate material

A technology of tap density and iron phosphate, applied in chemical instruments and methods, phosphorus compounds, inorganic chemistry, etc., can solve the problems of unfavorable lithium iron phosphate, large particle voids, etc., reduce the nucleation rate, and achieve uniform secondary particle size. , the effect of increasing the chance of collision

Inactive Publication Date: 2021-03-30
HUNAN YACHENG NEW MATERIAL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the agglomeration of the primary particles of iron phosphate produced by the related technology is relatively loose, and the secondary particles appear as irregular soft aggregates. When the particles are piled up, there are large gaps between the particles, so that the tap density can only reach 0.5-0.8g / cm 3 , which is extremely unfavorable for obtaining high tap density lithium iron phosphate

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  • Preparation method of high-tap-density iron phosphate material
  • Preparation method of high-tap-density iron phosphate material
  • Preparation method of high-tap-density iron phosphate material

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Embodiment 1

[0036] Embodiment 1 of the present invention is: a kind of preparation method of iron phosphate material of high tap density, comprises the following steps:

[0037] S1. Under the condition that the stirring rate is 400rpm, according to the molar ratio of iron element and phosphorus element is 1:1.3, quickly add ammonium hydrogen phosphate solution (1.2mol / L) to the first iron source ferric sulfate solution After ferric sulfate solution (0.6mol / L), control the temperature of the reaction system to 92°C, the reaction time is 3h, and gradually convert into white slurry to obtain ferric phosphate seeds;

[0038] S2. Under the condition that the stirring speed is 200rpm and the system temperature is 92°C, ferric sulfate solution (0.25mol / L) and ammonium monohydrogen phosphate solution (0.5mol / L) are fed at a feed rate of 1.5L / h, and Add the liquid to the ferric phosphate seed crystal. When the material reaches the upper limit of the reaction vessel volume, stop feeding, and keep t...

Embodiment 2

[0042] Embodiment 2 of the present invention is: a kind of preparation method of iron phosphate material of high tap density, comprises the following steps:

[0043] S1. Under the condition that the stirring rate is 500rpm, according to the molar ratio of iron element and phosphorus element is 1:1.2, quickly add ammonium dihydrogen phosphate solution (1.45mol / L) to ferric chloride solution (1.45mol / L) Finally, control the temperature of the reaction system to 88°C, and the reaction time is 3 hours, gradually transforming into a white slurry to obtain ferric phosphate seeds;

[0044] S2. Under the condition that the stirring speed is 220rpm and the system temperature is 88°C, ferric chloride solution (0.4mol / L) and ammonium dihydrogen phosphate solution (0.4mol / L) are fed at a feed rate of 1L / h, and Add to the ferric phosphate seed crystal, when the material reaches the upper limit of the volume of the reaction vessel, stop feeding, and keep the existing stirring speed and temper...

Embodiment 3

[0047] Embodiment 3 of the present invention is: a kind of preparation method of high tap density quasi-spherical ferric phosphate material, comprises the following steps:

[0048] S1. Under the condition of stirring rate of 480rpm, according to the molar ratio of iron element and phosphorus element of 1:1.15, quickly add ammonium hydrogen phosphate solution (1.3mol / L) to ferric nitrate solution (1.3mol / L) , control the temperature of the reaction system at 90°C, and the reaction time is 3h, gradually transforming into a white slurry to obtain iron phosphate seeds;

[0049] S2. Under the condition that the stirring rate is 200rpm and the system temperature is 90°C, feed ferric nitrate solution (1mol / L) and ammonium monohydrogen phosphate solution (1mol / L) at a feed rate of 1.5L / h, and flow Add the feed to the ferric phosphate seed crystal. When the material reaches the upper limit of the volume of the reaction vessel, stop feeding, and keep the current stirring rate and temper...

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Abstract

The invention discloses a preparation method of a high-tap-density iron phosphate material. The preparation method comprises the following steps: S1, quickly reacting a high-concentration iron sourcesolution with a high-concentration phosphorus source solution to obtain an iron phosphate seed crystal; and S2, slowly adding a low-concentration iron source solution and a low-concentration phosphorus source solution at a constant speed to realize growth of iron phosphate crystals so as to obtain the high-tap-density iron phosphate material. According to the method, the seed crystal reaction andthe crystallization reaction of iron phosphate are effectively separated, and the sphere-like micron-sized iron phosphate particles are successfully prepared. According to the spheroidic large-particle iron phosphate, primary particles are closely agglomerated, secondary particles are uniform in size, and extremely high tap density (larger than 1.05 g/cm<3>) is shown.

Description

technical field [0001] The invention relates to the technical field of lithium ion battery materials, in particular to a preparation method of a high tap density iron phosphate material. Background technique [0002] Lithium iron phosphate with an olivine structure has the advantages of abundant raw materials, stable discharge platform, long cycle life, and environmental protection. It is considered to be one of the most promising lithium-ion battery materials and is widely used in many fields such as energy storage. . However, due to the low tap density of lithium iron phosphate (0.8 ~ 1.3g / cm 3 ), resulting in a relatively low energy density of lithium iron phosphate batteries; the energy density of a single lithium iron phosphate battery is only 120W·h / kg, and the energy density after forming a battery pack is only 80W·h / kg. This greatly limits the further application of lithium iron phosphate batteries. [0003] In order to solve this problem, researchers are working ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B25/37H01M4/58H01M10/0525
CPCC01B25/375H01M4/5825H01M10/0525C01P2004/03C01P2006/11C01P2004/32C01P2004/50C01P2004/52C01P2004/61Y02E60/10
Inventor 彭超林奕丁建华万文治
Owner HUNAN YACHENG NEW MATERIAL CO LTD
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