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Preparation method for lithium ion secondary battery positive pole active substance lithium iron phosphate

A cathode active material, lithium iron phosphate technology, applied in battery electrodes, chemical instruments and methods, circuits, etc., can solve problems such as poor battery discharge performance at high currents, and achieve improved electrical conductivity, high current discharge performance, and improved The effect of conductivity

Active Publication Date: 2008-07-02
BYD CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0011] The purpose of the present invention is to overcome the defect of poor high-current discharge performance of the battery prepared by using the lithium iron phosphate prepared by the prior art, and provide a method for preparing the lithium iron phosphate that makes the battery have good high-current discharge performance

Method used

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  • Preparation method for lithium ion secondary battery positive pole active substance lithium iron phosphate
  • Preparation method for lithium ion secondary battery positive pole active substance lithium iron phosphate
  • Preparation method for lithium ion secondary battery positive pole active substance lithium iron phosphate

Examples

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Comparison scheme
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Embodiment 1

[0036] This embodiment illustrates the preparation of the positive electrode active material lithium iron phosphate provided by the invention

[0037] (1) Add 0.1 mole of Li 2 CO 3 , 0.2 mol FeC 2 o 4 2H 2 O, 0.2 mole NH 4 h 2 PO 4 Mix with glucose and 250 ml of absolute ethanol (Li:Fe:P molar ratio is 1:1:1), ball mill in a ball mill jar at a speed of 300 rpm for 12 hours, take it out, and dry it at 70°C;

[0038] (2) Under the protection of argon gas with a flow rate of 10 liters / minute, the mixture in step (1) was heated to 450° C. for sintering at a constant temperature at a rate of 2° C. / minute for 6 hours, cooled naturally to room temperature, then added sucrose, and Mix with 100 milliliters of absolute ethanol, ball mill for 1 hour at a speed of 150 rpm in a ball mill jar, take out, and dry at 70°C; the weight of the glucose in the step (1) and the sucrose in the step (2) The ratio is 2.5:1;

[0039] (3) Under the protection of argon gas with a flow rate of 10 ...

Embodiment 2

[0043] This embodiment illustrates the preparation of the positive electrode active material lithium iron phosphate provided by the invention

[0044] Lithium ferrous phosphate was prepared according to the method of Example 1, except that in step (2), the mixture in step (1) was heated to 450°C for sintering at a constant temperature of 6 hours at a heating rate of 2°C / min, and then naturally cooled to room temperature, then add sucrose, and stir and mix evenly, under the protection of argon with a flow rate of 10 liters / min, heat the above-mentioned sintered product to 700°C at a heating rate of 10°C / min and sinter at a constant temperature for 10 hours, then naturally cool to room temperature , jet milling to obtain LiFePO doped and coated with carbon 4 Composite material, other steps, each substance dosage ratio and condition are the same as embodiment 1.

[0045] The lithium ferrous phosphate composite material obtained above is passed through a 200 mesh sieve, and its m...

Embodiment 3

[0047] This embodiment illustrates the preparation of the positive electrode active material lithium iron phosphate provided by the invention

[0048] (1) 0.21 moles of LiOH, 0.2 moles of FeC 2 o 4 2H 2 O, 0.2 moles (NH 4 ) 2 HPO 4 Mix with sucrose and 250 ml of absolute ethanol (Li:Fe:P molar ratio is 1:1:1), ball mill in a ball mill jar at a speed of 300 rpm for 12 hours, take it out, and dry it at 70°C;

[0049] (2) Under the protection of argon gas with a flow rate of 10 liters / min, the mixture in step (1) was heated to 450°C at a constant temperature for 6 hours at a rate of 2°C / min and sintered at a constant temperature, then naturally cooled to room temperature, and then polyacrylamide was added , and mixed with 100 milliliters of absolute ethanol, ball milled for 0.5 hour at a speed of 200 rev / min in a ball mill jar, taken out, and dried at 70°C; the sucrose in the step (1) and the polypropylene in the step (2) The weight ratio of dilute amides is 3.2:1;

[0050...

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Abstract

The invention relates to a preparation method of lithium iron phosphate, an active substance applied in the anode of lithium-ion secondary batteries. The method comprises a mixture that contains lithium compound, iron compound, phosphorus compound and carbon source additive is sintered and cooled to get a sintering product; wherein, the sintering method comprises the step: the mixture that contains lithium compound, iron compound, phosphorus compound and partial carbon source additive is sintered at a first constant sintering temperature, then a mixture of the product acquired at the first sintering temperature and the residual carbon source additive is sintered at a second constant sintering temperature, and the second sintering temperature is at least 100 DEG C higher than the first sintering temperature. The batteries made of the lithium iron phosphate prepared by the method of the invention have markedly improved discharge performance at high current.

Description

technical field [0001] The present invention relates to a preparation method of a positive electrode active material of a battery, more specifically, to a preparation method of lithium iron phosphate, a positive electrode active material of a lithium ion secondary battery. Background technique [0002] As a high-energy chemical power source, lithium-ion batteries have been widely used in mobile communications, notebook computers, video cameras, cameras, portable instruments and other fields. . LiFePO 4 It is a research hotspot of positive electrode active materials for lithium-ion batteries. LiFePO 4 As a positive electrode active material for lithium-ion batteries, compared with other batteries, it has good electrochemical performance, the charging and discharging platform is very stable, and the structure is stable during charging and discharging. The advantages of use and wide range of raw material sources are currently hot spots in the battery industry's development ...

Claims

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Application Information

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IPC IPC(8): C01B25/45H01M4/58
CPCY02E60/10
Inventor 戴权沈菊林肖峰
Owner BYD CO LTD
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