Method for preparing lithium iron phosphate as a positive electrode active material for a lithium ion secondary battery

A cathode active material, lithium iron phosphate technology, applied in secondary batteries, battery electrodes, chemical instruments and methods, etc., can solve the problem of low initial discharge specific capacity, high current discharge performance and cycle performance, lithium iron phosphate Large crystal grain size and other problems, to achieve high initial discharge specific capacity, high current discharge performance and cycle performance improvement, and high current discharge performance and cycle performance.

Active Publication Date: 2009-10-28
BYD CO LTD
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  • Abstract
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  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is in order to overcome the lithium ferrous phosphate prepared by the existing method such as larger crystal particle size, uneven particle size distribution and low initial discharge specific capacity and high current discharge performance of the battery made by the lithium ferrous phosphate. And the defect of poor cycle performance, a kind of preparation method of lithium ferrous phosphate is provided, the lithium ferrous phosphate crystal grain size that is made by this method is smaller, the particle size distribution is uniform and the first discharge of the battery that is made by this ferrous phosphate High specific capacity, high current discharge performance and good cycle performance

Method used

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  • Method for preparing lithium iron phosphate as a positive electrode active material for a lithium ion secondary battery
  • Method for preparing lithium iron phosphate as a positive electrode active material for a lithium ion secondary battery
  • Method for preparing lithium iron phosphate as a positive electrode active material for a lithium ion secondary battery

Examples

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Effect test

Embodiment 1

[0028] This example illustrates the preparation method of the positive electrode active material lithium iron phosphate provided by the present invention.

[0029] 43.3 g LiOH·H 2 O (Shanghai Zhongli Industrial Co., Ltd., special grade for batteries, LiOH·H 2 O content is 97.01% by weight), 80.4 grams median particle diameter D 50 0.37 microns, D 95 2.50 µm Fe 2 o 3 (ELEMENTIS, Fe 2 o 3 The content is 99.3%), 115.0 grams of H 3 PO 4 (Guangdong Guanghua Chemical Factory Co., Ltd., analytically pure, H 3 PO 4 content is 85.2%), 38.2 grams of sucrose (Guangdong Guanghua Chemical Factory Co., Ltd., analytically pure) and 200 milliliters of deionized water are placed in the reactor, stirred at a rate of 200 rpm for 1.5 hours, then dried at 120 ° C After 8 hours, the precursor was obtained. The precursor is heated up to 690°C at a rate of 5°C / min, sintered at a constant temperature of 690°C in a nitrogen atmosphere for 8 hours, and naturally cooled to room temperature to ...

Embodiment 2-6

[0032] Prepare the positive electrode active material lithium ferrous phosphate according to the method of Example 1, the difference is the type and amount of lithium source, the amount and particle size of ferric oxide, the amount of phosphoric acid, the type and amount of carbon source, solvent The type and dosage, drying temperature and drying time, and sintering temperature and sintering time are shown in Table 1.

[0033] Table 1

[0034] Example

Embodiment 7

[0036] 43.3 g LiOH·H 2 O (Shanghai Zhongli Industrial Co., Ltd., special grade for batteries, LiOH·H 2 O content is 97.01% by weight), 80.4 grams median particle diameter D 50 0.37 microns, D 95 2.50 µm Fe 2 o 3 (ELEMENTIS, Fe 2 o 3 The content is 99.3%), 115.0 grams of H 3 PO 4 (Guangdong Guanghua Chemical Factory Co., Ltd., analytically pure, H 3 PO 4 Content is 85.2%), 38.2 grams of sucrose (Guangdong Guanghua Chemical Factory Co., Ltd., analytically pure), 2.45 grams (0.01 mole) Ni(NO 3 ) 3 , 1.89 g (0.01 mol) Zn(NO 3 ) 2 and 200 ml of deionized water were placed in a reactor, stirred at a rate of 200 rpm for 1.5 hours, and then dried at 120° C. for 8 hours to obtain a precursor. The precursor was heated up to 500°C at a rate of 2°C / min in a nitrogen atmosphere, and sintered at 500°C for 4 hours. Then continue to heat up to 700°C at a rate of 2°C / min, and sinter at 700°C for 10 hours. The sintered product is naturally cooled to room temperature, and the posi...

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Abstract

Disclosed herein is a method for preparing lithium iron phosphate as a positive electrode active material for a lithium ion secondary battery comprising drying and sintering a mixture containing a lithium source, ferric oxide, phosphoric acid, a carbon source, and a solvent, in which the solvent is water and / or water soluble organic solvent. The lithium iron phosphate prepared by the inventive method has small particle size and uniform particle size distribution, and the battery prepared from the lithium iron phosphate has high initial discharge specific capacity, and good large-current discharge property and cycle performance.

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 chemical power source with high specific capacity, 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. Compared with other positive electrode active materials for lithium-ion batteries, LiFePO 4 It has good electrochemical performance, the potential platform of charge and discharge is very stable, the structure is stable during charge and discharge, and LiFePO 4 It also has the advantages of non-toxic, non-polluting, good safety performance, can be used in high-temperat...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B25/45H01M4/58H01M10/40
CPCY02E60/12Y02T10/7011Y02E60/122Y02E60/10
Inventor 陈小勇徐茶清贾文雯
Owner BYD CO LTD
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