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Preparation method of nano lithium iron phosphate with high tap density

A technology of tap density and lithium iron phosphate, applied in chemical instruments and methods, phosphorus compounds, inorganic chemistry, etc., can solve the problems of uneven particle size, poor conductivity, poor conductivity, etc., to facilitate the transmission of ions, improve Tap density, effect of increasing electrical conductivity

Inactive Publication Date: 2011-01-05
IRICO
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] Moreover, most of the preparation of lithium iron phosphate positive electrode materials is mostly prepared by solid-state method sintering, and then carbon-coated to increase the conductivity of lithium iron phosphate. In fact, iron phosphate prepared by solid-state method Even if lithium can reach a smaller particle size, carbon can only adhere to the surface of micron-sized particles, and its interior is still poorly conductive, and the solid-phase method prepares lithium iron phosphate with small particle size mostly by crushing , and in the crushing process, on the one hand, the obtained particle size is not uniform, and the efficiency is low, and secondly, it is easy to damage the structure of the material, which fundamentally determines its poor electrical conductivity.

Method used

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  • Preparation method of nano lithium iron phosphate with high tap density
  • Preparation method of nano lithium iron phosphate with high tap density
  • Preparation method of nano lithium iron phosphate with high tap density

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] 1) Carry out a granulation: take by weighing 1.5mol ferrous sulfate, 1.5mol phosphoric acid (calculated by the effective content of 85% volume concentration phosphoric acid), be dissolved in the deionized water of 3000ml, add 0.15mol complexing agent ethylene glycol, constantly Stir and slowly add 4500ml of 1.5mol lithium hydroxide solution;

[0028] 2) The above solution was continuously stirred in an oil bath at 110°C for 1 hour; a green precipitate was generated, which was suction filtered and washed to obtain a solid product;

[0029] 3) The obtained solid product was dried in a vacuum drying oven at 60° C. for 6 hours; the dried precursor was ball milled to obtain a precursor powder with a particle size of 30 nm;

[0030] 4) Dissolve the obtained precursor powder and organic carbon sucrose in deionized water at a mass ratio of 1:0.03, stir and mix them thoroughly, then place them in a vacuum drying oven at 60° C. for 12 hours to obtain a spare precursor;

[0031] ...

Embodiment 2

[0035] 1) carry out a granulation: take by weighing 1mol ferrous chloride, 1mol phosphoric acid (calculated by the effective content of 85% volume concentration phosphoric acid), be dissolved in the deionized water of 2000ml, add 0.1mol complexing agent ethylene glycol and triethanolamine, Stir constantly, slowly add 4500ml of 2mol lithium carbonate solution;

[0036] 2) The above solution was continuously stirred in an oil bath at 140°C for 2 hours; a green precipitate was generated, which was suction filtered and washed to obtain a solid product;

[0037] 3) drying the obtained solid product in a vacuum drying oven at 80° C. for 10 h, and ball milling the dried precursor to obtain a precursor powder with a particle size of 100 nm;

[0038] 4) Dissolve the obtained precursor powder, organic carbon glucose, and citric acid in deionized water at a mass ratio of 1:0.1, stir and mix thoroughly, and dry in a vacuum oven at 80°C for 18 hours to obtain a spare precursor body;

[0...

Embodiment 3

[0043] 1) Carry out a granulation: take by weighing 1.5mol ferrous sulfate and ferrous chloride, 1.5mol phosphoric acid (according to the effective content calculation of 85% volume concentration phosphoric acid), be dissolved in the deionized water of 3000ml, add 0.15mol complexing agent Ethylene glycol and triethanolamine, stirring continuously, slowly add 4500ml of 1.5mol lithium sulfate solution;

[0044] 2) The above solution was continuously stirred in an oil bath at 266°F for 1.5 hours; a green precipitate was generated, and the green precipitate was subjected to suction filtration and washed to obtain a solid product;

[0045] 3) drying the obtained solid product in a vacuum drying oven at 70° C. for 8 hours; the dried precursor was ball milled to obtain a precursor powder with a particle size of 50 nm;

[0046] 4) Dissolve the obtained precursor powder, organic carbon sucrose, rock sugar and citric acid in deionized water at a mass ratio of 1:0.06, stir and mix thorou...

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Abstract

The invention discloses a preparation method of nano lithium iron phosphate with high tap density, which is characterized by comprising the following steps of: (1) primary granulation: dissolving soluble ferrite and phosphoric acid in deionized water, adding a complexing agent and slowly adding a lithium salt solution while stirring continuously; (2) continuously stirring the solution in an oil bath until green precipitate is produced, filtering by pumping, and washing to obtain solid products; (3) drying the solid products in vacuum, and pulverizing by ball milling to obtain precursor powder; (4) dissolving the precursor powder and organic carbon in deionized water, fully stirring and mixing, and drying in vacuum to obtain standby precursor powder; (5) secondary granulation: stirring the product of the primary granulation in a vacuum container for granulation until the material becomes semi-dry particles; and (6) firstly drying the granulated powder in a vacuum drying box, and then sintering under the protection of inert atmosphere to obtain spherical lithium iron phosphate with micron particle size. The transmission rate of ions and electrons can be increased by nanosizing the lithium iron phosphate, and the conductive property of the lithium iron phosphate is further improved.

Description

technical field [0001] The invention belongs to the field of green energy materials, and relates to a preparation technology of lithium ion battery cathode materials, in particular to a preparation method of high tap density nanometer lithium iron phosphate. Background technique [0002] In lithium-ion batteries, the cathode material is the most important component and the key to determining the performance of lithium-ion batteries. Currently, the main cathode material is LiCoO 2 , LiNiO 2 , LiMn 2 o 4 . Among them, LiCoO 2 It is currently the only positive electrode material that has been industrialized and commercialized on a large scale, and more than 90% of lithium-ion batteries use this material. However, the Co used in this material is expensive, has a low capacity, and is highly toxic, and there are certain safety issues. LiNiO 2 The cost is low, the capacity is high, but the preparation is difficult, the thermal stability is poor, and there is a large potenti...

Claims

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Application Information

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IPC IPC(8): C01B25/45H01M4/58
CPCY02E60/10
Inventor 王少卿
Owner IRICO