LiFePO4/C preparation method

A technology of hydrothermal method and precipitant, which is applied in the direction of electrode manufacturing, electrical components, battery electrodes, etc., can solve problems such as the increase of ferric iron content in lithium ferrous phosphate, the increase of industrial production costs, and the increase of lithium recovery process. Achieve excellent electrochemical performance, cost reduction, uniform particle size distribution

Inactive Publication Date: 2010-01-20
四川川大中德环保技术有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Publication number is CN101117216, CN101121509 etc. all adopted hydrothermal method to prepare ferrous phosphate lithium, mainly use lithium hydroxide, ferrous sulfate, phosphoric acid as raw material, the common problems that these methods exist are: (1) used excessive more and Expensive lithium-containing raw materials (Li:Fe:P molar ratio is 3.0~3.15:1:1.0~1.15), need to increase the subsequent lithium recovery process, which will increase the cost of industrial production
(2) Increased the possibility of forming iron hydroxide and ferric iron, resulting in an increase in the content of ferric iron in the product lithium iron phosphate, which is harmful to the electrochemical performance of the material

Method used

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  • LiFePO4/C preparation method
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  • LiFePO4/C preparation method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] In this example, LiFePO 4 The processing steps of the / C preparation method are as follows:

[0034] (1) Synthesis of LiFePO by hydrothermal method 4

[0035] The raw materials and their supplies are:

[0036] Iron 0.2mol (FeSO 4 ·7H 2 O 55.61 grams), phosphorus 0.2mol (85% H 3 PO 4 23.0586 grams), lithium 0.18mol (LiOH·H 2 O7.5528 grams), ascorbic acid 0.0091mol (1.6 grams), urea 0.09mol (5.406 grams), nanoscale LiFePO 4 0.12 grams;

[0037] The operation is:

[0038] FeSO 4 ·7H 2 O and ascorbic acid were added to 300 mL deionized water to prepare an iron source-antioxidant solution, and LiOH·H 2 O was added with 200mL deionized water to prepare a lithium source solution, and the H 3 PO4 Add 150mL of deionized water to make a phosphorus source solution, then drop the phosphorus source solution into the lithium source solution at room temperature (26°C) and normal pressure under stirring, and at the same time, add urea to the lithium source solution to act ...

Embodiment 2

[0044] In this example, LiFePO 4 The processing steps of the / C preparation method are as follows:

[0045] (1) Synthesis of LiFePO by hydrothermal method 4

[0046] The raw materials and their supplies are the same as in Example 1.

[0047] The operation is basically the same as that of Example 1, except that: when the temperature of the autoclave reaches 210° C., the timer is started, and the temperature is kept at 210° C. for 2 hours.

[0048] (2) Carbon doping and calcination

[0049] The LiFePO prepared in step (1) 4 Weigh 20 grams, add 6 grams of glucose, and use a ball mill to grind LiFePO 4 Mix well with glucose, then LiFePO 4 The mixture with glucose was put into a tube furnace and heated to 500°C under the protection of nitrogen for 40 hours. After the heat preservation was completed, it was cooled to room temperature with the furnace to obtain LiFePO 4 / C, its X-ray diffraction pattern is shown in figure 2 , with an average particle size of 1.0 microns and ...

Embodiment 3

[0052] In this example, LiFePO 4 The processing steps of the / C preparation method are as follows:

[0053] (1) Synthesis of LiFePO by hydrothermal method 4

[0054] The raw materials and their supplies are:

[0055] Iron 0.2mol (FeCl 2 25.349 grams), phosphorus 0.2mol (NH 4 h 2 PO 4 23.005 g), lithium 0.19 mol (LiAc.2H 2 O19.3838 grams), cetyltrimethylammonium bromide 0.004mol (1.456 grams), formamide 0.475mol (21.394 grams), nanoscale LiFePO 4 1.6 grams.

[0056] The operation is:

[0057] FeCl 2 and cetyltrimethylammonium bromide plus 500mL deionized water to prepare iron source-antioxidant solution, LiAc.2H 2 O was added with 300mL deionized water to prepare a lithium source solution, and the NH 4 h 2 PO 4 Add 300mL of deionized water to prepare a phosphorus source solution, then drop the phosphorus source solution into the lithium source solution at room temperature (25°C) and normal pressure under stirring, and at the same time, add formamide to the lithium...

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Abstract

A LiFePO4/C preparation method comprises the following steps: (1) hydrothermal method is used to synthesize LiFePO4, the molar ratio of lithium to iron and phosphorus is 0.9-1.2:1:1, the molar ratio of precipitant to lithium is 0.5-2.5:1, the molar ratio of antioxidant to iron is 1:15-50; after crystal inducer is added in the mixed solution containing lithium, iron and phosphorus, the solution is transferred to an autoclave, then the autoclave is sealed and a reaction is performed in the autoclave at 160 -210 DEG C for 2-3h while stirring; (2) carbon is doped to perform calcinations, organic carbon source is doped in LiFePO4 prepared in the step 1, then a ball mill is used for mixing LiFePO4 and organic carbon source evenly, then the obtained mixture is added in a calcining furnace to heating at 500-850 DEG C under the protection of inert gas while keeping the temperature for 3-40h, the product is cooled along with the furnace to room temperature after heat insulation and the LiFePO4/C is obtained.

Description

technical field [0001] The invention belongs to LiFePO 4 / C preparation field, in particular to a preparation of LiFePO by hydrothermal method 4 , and then doped with carbon to prepare LiFePO 4 / C method. Background technique [0002] As a device that directly converts chemical energy into electrical energy, batteries play an important role in the national economy and defense industry. Especially in recent years, the rapid development of electronics, information industry and transportation clean energy has put forward higher requirements for high-capacity secondary batteries. Compared with other rechargeable batteries such as lead-acid batteries, nickel-cadmium batteries, and nickel-metal hydride batteries, lithium-ion batteries have the characteristics of high working voltage, large specific capacity, low self-discharge rate, long cycle life, no memory effect, and no environmental pollution. It is an ideal green chemical energy developed in the 21st century. Electrode ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/04H01M4/58H01M4/62
CPCY02E60/12Y02E60/10
Inventor 钟本和郭孝东刘恒唐红
Owner 四川川大中德环保技术有限公司
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