Method for uniformly coating carbon on nano lithium iron phosphate

A lithium iron phosphate and carbon coating technology, which is applied to electrical components, battery electrodes, circuits, etc., can solve problems such as uneven particle size, poor electrical conductivity, and inability to fully coat carbon, and achieve good electrical conductivity and high electrical conductivity. high efficiency effect

Inactive Publication Date: 2011-01-12
IRICO
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

6. No memory effect
[0004] Moreover, most of the preparation of lithium iron phosphate positive electrode materials is mostly prepared by solid phase sintering, and then it is ball milled and mixed with carbon for carbon coating to increase the conductivity of lithium iron phosphate. In fact, solid The particle size of the lithium iron phosphate prepared by the phase method is relatively large, and the carbon cannot be directly mixed and evenly coated on the outside of the lithium

Method used

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  • Method for uniformly coating carbon on nano lithium iron phosphate
  • Method for uniformly coating carbon on nano lithium iron phosphate
  • Method for uniformly coating carbon on nano lithium iron phosphate

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] 1) Weigh 1 mol of ferrous sulfate and 1 mol of phosphoric acid (calculated based on the effective content of phosphoric acid at a volume concentration of 85%) in a molar ratio of 1:1, dissolve them in 2000 ml of deionized water, and add 0.1 mol of complexing agent ethylene glycol , Under constant stirring, slowly add 3000ml of 3mol lithium hydroxide solution;

[0023] 2) Continue stirring the above solution in an oil bath at 110°C for 1 hour; until a green precipitate is produced, the green precipitate is suction filtered and washed to obtain a solid product;

[0024] 3) Dry the obtained solid product in a vacuum drying oven at a temperature of 60°C for 6 hours; the dried precursor is ball-milled to obtain a precursor powder with a particle size of 20 nm;

[0025] 4) Dissolve the obtained precursor and nano-scale amorphous carbon black in deionized water at a mass ratio of 1:0.05, stir thoroughly and evenly disperse and mix, and place in a vacuum drying oven at 60°C for 5 hour...

Embodiment 2

[0029] 1) Weigh 2 mol of ferrous chloride and 2 mol of phosphoric acid (calculated based on the effective content of phosphoric acid at a volume concentration of 85%) in a molar ratio of 1:1, dissolve them in 4000 ml of deionized water, and add 0.2 mol of complexing agent ethylene dichloride Alcohol and triethanolamine, slowly add 6000ml of 2mol lithium carbonate solution under constant stirring;

[0030] 2) Continue stirring the above solution in an oil bath at 120°C for 1.5 hours; until a green precipitate is produced, the green precipitate is suction filtered and washed to obtain a solid product;

[0031] 3) Put the obtained solid product in a vacuum drying oven at a temperature of 70°C; dry for 8 hours; ball mill the dried precursor to obtain a precursor powder with a particle size of 50 nm;

[0032] 4) Dissolve the obtained precursor and nano-scale amorphous carbon graphite in deionized water at a mass ratio of 1:0.1, stir thoroughly and evenly disperse and mix, and place them i...

Embodiment 3

[0036] 1) Weigh 1.5 mol of ferrous sulfate and ferrous chloride hydrate, 1.5 mol of phosphoric acid (calculated based on the effective content of phosphoric acid at a volume concentration of 85%) in a molar ratio of 1:1, and dissolve in 3000 ml of deionized water , Add 0.2mol of complexing agent polypropylene ethylene, slowly add 3mol of lithium carbonate and lithium sulfate hydrate solution 4500ml under constant stirring;

[0037] 2) Continue stirring the above solution in an oil bath at 140°C for 2 hours; until a green precipitate is produced, the green precipitate is suction filtered and washed to obtain a solid product;

[0038] 3) Dry the obtained solid product in a vacuum drying oven at a temperature of 80°C for 10 hours; the dried precursor is pulverized by ball milling to obtain a precursor powder with a particle size of 100 nm;

[0039] 4) Dissolve the obtained precursor, nano-scale amorphous carbon graphite and artificial graphite in deionized water at a mass ratio of 1:0.1...

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Abstract

The invention discloses a method for uniformly coating carbon on nano lithium iron phosphate, which is characterized by comprising the following steps of: 1) weighting soluble ferrous salt and phosphoric acid according to a proportion, dissolving the ferrous salt and the phosphoric acid in deionized water, adding a complexing agent into the mixture, and slowly adding lithium salt solution into the mixture under continuous stirring; 2) continuously stirring the solution in an oil bath until a green precipitate is generated, and performing suction filtration and washing to obtain a solid product; 3) drying the solid product in a vacuum drying oven, and performing ball milling on the dried solid product to obtain precursor powder; 4) dissolving the precursor powder and nano amorphous carbon in the deionized water, uniformly dispersing and mixing the precursor powder and the nano amorphous carbon, and drying the mixture to obtain a nano carbon-coated precursor; and 5) grinding and breaking the nano carbon-coated precursor, and sintering to obtain the uniform carbon-coated nano lithium iron phosphate. By adopting method, the nano-size carbon is fully dispersed in the solution and is uniformly coated on lithium iron phosphate granules through the surface acting force among nano granules, and the transmission rate of ions and electrons, thereby improving the electric conductivity of the nano lithium iron phosphate.

Description

Technical field [0001] The invention relates to a preparation technology of a lithium ion battery cathode material, in particular to a method for uniform carbon coating of nano 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. Lithium iron phosphate materials have the characteristics of good safety, excellent cycle performance, environmental friendliness, and a wide range of raw materials. Among them, lithium, iron, and phosphorus are all elements with abundant reserves on the earth, especially the iron-based materials have a wide range of raw materials and low prices. Recognized as the preferred cathode material for the new generation of lithium-ion batteries, it has become the key research and development direction of major developed countries in the world today. Moreover, due to its stability at high temperatures and the elect...

Claims

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Application Information

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IPC IPC(8): H01M4/1397
CPCY02E60/122Y02E60/10
Inventor 王少卿
Owner IRICO
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