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Porous lithium iron phosphate/carbon composite microspheres and preparation method thereof

A lithium iron phosphate and carbon composite technology, used in phosphorus compounds, chemical instruments and methods, structural parts, etc., can solve the problems of low output, inability to industrialize production, uniform molecular level, and inability to achieve solid-phase methods, and achieve high tap density. , The effect of improving energy density and convenient operation

Inactive Publication Date: 2013-05-01
QINGDAO UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Among them, the high-temperature solid-phase method and liquid-phase precipitation method are more practical in industrial production, but the solid-phase method cannot achieve uniformity at the molecular level, while the ordinary liquid-phase precipitation method is more demanding, generally needs to adjust pH, etc., and is prone to impurities Mutually
Although the product of the hydrothermal / solution heat method is relatively pure, the yield is small and cannot be industrialized
The sol-gel method has the advantages of uniform mixing and good carbon coating, but the reaction conditions are relatively harsh, the drying shrinkage is large, and it is difficult to realize industrial production

Method used

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  • Porous lithium iron phosphate/carbon composite microspheres and preparation method thereof
  • Porous lithium iron phosphate/carbon composite microspheres and preparation method thereof
  • Porous lithium iron phosphate/carbon composite microspheres and preparation method thereof

Examples

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Effect test

Embodiment 1

[0033] The preparation method of porous lithium iron phosphate / carbon composite microspheres described in this embodiment specifically includes the following steps:

[0034] (1) At room temperature, 0.1 mol of Fe(NO 3 ) 3 9H 2 O and 0.1 mol of H 3 PO 4 (H with a purity of 85% 3 PO 4 solution) mixed with 100 mL of ethanol, ultrasonically or stirred to dissolve, then added 0.1 mol LiOH and stirred until dissolved.

[0035] (2) Add 0.1L 1mol / L oxalic acid ethanol solution dropwise to the above mixed solution, accompanied by vigorous stirring during the addition. After reacting for 1 hour, a uniform yellow jelly was obtained, which was fully dried at 80° C. to obtain a yellow-white iron phosphate oxalate powder.

[0036] (3) Disperse 0.1 mol of iron phosphate oxalate powder and 8 g of glucose into 30 mL of water, mix and grind for 1 hour, then fully dry at 80°C, and then calcinate the mixture at 650°C under the protection of argon / hydrogen gas containing 5% hydrogen 24 h t...

Embodiment 2

[0038] The preparation method of porous lithium iron phosphate / carbon composite microspheres described in this embodiment specifically includes the following steps:

[0039] (1) Add 0.1 mol Fe(NO 3 ) 3 9H 2 O and containing 0.1 mol LiH 2 PO 4 Aqueous solution (the amount of water used is only LiH 2 PO 4 Just dissolve it) mix and add to 200 mL ethanol and stir to dissolve.

[0040] (2) Add 100 mL of 1 mol / L oxalic acid ethanol solution dropwise to the above mixed solution, accompanied by vigorous stirring during the addition. After reacting for 3 hours, a uniform yellow jelly was obtained, which was fully dried at 60 °C to obtain a yellow-white powder.

[0041] (3) Add 50% of the precursor mass of sucrose, disperse it into 5 ml of water and grind it for 1 h, then fully dry it at 80 °C, and then calcinate the mixture at 700 °C for 10 h under the protection of argon / hydrogen gas containing 5% hydrogen to obtain the final product.

Embodiment 3

[0043] The preparation method of porous lithium iron phosphate / carbon composite microspheres described in this embodiment specifically includes the following steps:

[0044] (1) Mix 10 mmol iron acetate and 10 mmol H 3 PO 4 Mix and add 20 mL of ethanol, sonicate or stir to dissolve, then add 0.01 mol lithium acetate and stir until dissolved.

[0045] (2) Add 10 mL of 1.5 mol / L oxalic acid ethanol solution dropwise to the above mixed solution, accompanied by vigorous stirring during the addition. After 3 hours, a uniform yellow jelly was obtained, which was aged and dried at 60 °C to obtain a yellow-white powder.

[0046] (3) After adding citric acid with 50% of the mass of the precursor and mixing and milling for 1 h, the mixture was calcined at 750 °C for 10 h under the protection of argon / hydrogen gas containing 5% hydrogen to obtain the final product.

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Abstract

The invention provides porous lithium iron phosphate / carbon composite microspheres and a preparation method thereof. The porous lithium iron phosphate / carbon composite microspheres and the preparation method thereof are characterized in that iron phosphate oxalate is used as a precursor and the preparation method comprises the following steps: (1) dispersing solution of iron salt and phosphate solution into a precipitating agent ethanol, adding lithium salt, carrying out ultrasonic stirring to enable the solution of iron salt, the phosphate solution and the lithium salt to be totally dissolved, and adding a certain quantity of oxalic ethanol solution into the obtained solution; (2) placing the obtained mixture into an oven to dry at a certain temperature so as to obtain a yellow jelly iron phosphate oxalate precursor; and (3) after mixing a carbon source and the iron phosphate oxalate precursor, calcining to obtain the porous lithium iron phosphate / carbon composite microspheres. The preparation method provided by the invention is low in cost and is simple and easy to operate; the pH does not need to be regulated; the products have high purity, high tap density and good repeatability; the products are spherical particles formed by self-assembling disk nano-scale particles, and thus, the specific surface area is large; and moreover, the diffusion path of lithium ions is greatly shortened, so that the porous lithium iron phosphate / carbon composite microspheres have excellent electrochemical property and are suitable for large-scale production.

Description

technical field [0001] The invention relates to a preparation method of a positive electrode material of a lithium ion battery, in particular to a porous lithium iron phosphate / carbon composite microsphere and a preparation method thereof. Background technique [0002] Lithium-ion batteries have the advantages of high voltage, high energy density, good cycle performance, and no memory effect, and are widely used. The price of positive electrode materials accounts for a considerable proportion of the entire cost of lithium-ion batteries. Lithium iron phosphate (LiFePO) with olivine structure 4 ) has a fairly stable lattice structure, stable voltage platform and high theoretical capacity, and is recognized as a safe, cost-effective, long-life, and environmentally friendly lithium-ion battery cathode material. [0003] Lithium iron phosphate also has some shortcomings that hinder its practical application. The main points are as follows: 1. The electronic conductivity and ioni...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/58C01B25/45H01M4/62
CPCY02E60/12Y02E60/10
Inventor 李桂村刘涛刘宁安姚元路鞠署元李岩彭红瑞陈克正
Owner QINGDAO UNIV OF SCI & TECH
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