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 p

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

Experimental program
Comparison scheme
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Example Embodiment

[0035] Example 1

[0036] This example illustrates the preparation of the positive electrode active material lithium ferrous phosphate provided by the present invention

[0037] (1) 0.1 mole of Li 2 CO 3 , 0.2 mol FeC 2 O 4 ·2H 2 O, 0.2 mol NH 4 H 2 PO 4 Mix with glucose and 250 milliliters of dehydrated alcohol (Li: Fe: P mol ratio is 1: 1: 1), ball-milled at a speed of 300 rev / min for 12 hours in a ball-milling jar, taken out, and dried at 70 °C;

[0038] (2) under the argon protection that the flow rate is 10 liters / min, the mixture of step (1) is heated to 450 ℃ of constant temperature sintering for 6 hours at a temperature increase rate of 2 ℃ / min, naturally cooled to room temperature, then added sucrose, and Mixed with 100 milliliters of absolute ethanol, ball-milled at a speed of 150 rev / min for 1 hour in a ball-milling tank, taken out, and dried 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] (...

Example Embodiment

[0042] Example 2

[0043] This example illustrates the preparation of the positive electrode active material lithium ferrous phosphate provided by the present invention

[0044] The 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 6 hours at a heating rate of 2°C / min, and then cooled to 450°C for 6 hours. room temperature, then add sucrose, stir and mix evenly, under the protection of argon with a flow rate of 10 liters / min, the above sintered product is heated to 700 ℃ at a heating rate of 10 ℃ / min for 10 hours at a constant temperature and sintered for 10 hours, and naturally cooled to room temperature , jet pulverization to obtain LiFePO doped and coated with carbon 4 For the composite material, other steps, the proportions and conditions of the amount of each substance are the same as those in Example 1.

[0045] The above obtained lithium iron phosphate composite materia...

Example Embodiment

[0046] Example 3

[0047] This example illustrates the preparation of the positive electrode active material lithium ferrous phosphate provided by the present invention

[0048] (1) 0.21 mol LiOH, 0.2 mol FeC 2 O 4 ·2H 2 O, 0.2 mol (NH 4 ) 2 HPO 4 Mix with sucrose and 250 milliliters of dehydrated alcohol (Li: Fe: P molar ratio is 1: 1: 1), ball-milled at a speed of 300 rev / min for 12 hours in a ball-milling jar, taken out, and dried at 70 °C;

[0049] (2) under the argon protection that the flow rate is 10 liters / min, the mixture of step (1) is heated up to 450 ℃ of constant temperature sintering for 6 hours at a temperature increase rate of 2 ℃ / min, naturally cooled to room temperature, and then polyacrylamide is added , and mixed with 100 ml of absolute ethanol, ball-milled at a speed of 200 rpm for 0.5 hours in a ball-milling tank, taken out, and dried at 70 °C; the sucrose in the step (1) and the polypropylene in the step (2) were The weight ratio of dilute amide i...

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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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