Method for preparing active substance lithium iron phosphate for lithium ion secondary battery anode

A positive electrode active material, lithium iron phosphate technology, applied in the direction of electrode manufacturing, battery electrodes, chemical instruments and methods, etc., can solve the problems of good cycle performance, low production cost, high initial discharge specific capacity, etc., and achieve high discharge specific capacity , cycle performance improvement, cycle performance significant effect

Inactive Publication Date: 2009-03-04
BYD CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to overcome the lithium ferrous phosphate crystal particle size that adopts existing method to prepare is bigger, particle size distribution is uneven, production cost is higher and the first time discharge specific capacity of the battery that is made by this lithium ferrous phosphate is low, cycle The defect of poor performance provides a preparation method of lithium ferrous phosphate, the lithium ferrous phosphate crystal particle size made by the method is small, the particle size distribution is uniform, the production cost is low and the battery made by the lithium ferrous phosphate The first discharge specific capacity is high and the cycle performance is good

Method used

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  • Method for preparing active substance lithium iron phosphate for lithium ion secondary battery anode
  • Method for preparing active substance lithium iron phosphate for lithium ion secondary battery anode
  • Method for preparing active substance lithium iron phosphate for lithium ion secondary battery anode

Examples

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Embodiment 1

[0024] This example illustrates the preparation method of the positive electrode active material lithium iron phosphate provided by the present invention.

[0025] 43.3 g LiOH·H 2 O (Shanghai Zhongli Industrial Co., Ltd., special grade for batteries, LiOH·H 2 O content 97.01%), 80.4 grams median particle size D 50 0.37 microns, D 95 2.50 µm Fe 2 o 3 (ELEMENTIS, Fe 2 o 3 Content 99.3%), 115.0 g 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 was sintered at a constant temperature of 690° C. for 8 hours in a nitrogen atmosphere, and then naturally cooled to room temperature to obtain the positive electrode active material lithium iron phosp...

Embodiment 2-6

[0028] Prepare the positive electrode active material lithium ferrous phosphate according to the method of Example 1, the difference lies in the lithium source and its amount, the amount and particle size of ferric oxide, the amount of phosphoric acid, the carbon source and its amount, and the amount of deionized water , drying temperature and drying time, sintering temperature and sintering time, the specific differences are shown in Table 1.

[0029] Table 1

[0030] Example Example 2 Example 3 Example 4 Example 5 Example 6 Lithium source LiOH·H 2 o LiOH·H 2 o Li2CO 3 Li 2 CO 3 Li 2 CO 3 The amount of lithium source (g) 42 45 39 39 38 The amount of ferric oxide (grams) 80 85 80 80 80 Particle size D of ferric oxide 50 (microns) 0.42 0.66 0.31 0.37 0.50 Particle size D of ferric oxide 95 (microns) 2.53 4.89 1.97 2.50 3.64 Amount of phosphoric acid (g) 115 118 115 114 115 carbon s...

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Abstract

The invention discloses a preparation method of lithium ferrous phosphate which is an active material of the anode of a lithium-ion secondary battery; the method comprises the following steps: lithium source, iron source, phosphorus source and carbon source are mixed in water, then dried and sintered; wherein, the iron source is ferric oxide and the phosphorus source is phosphoric acid. The lithium ferrous phosphate obtained by adopting the method has less crystal particle size, uniform distribution of particle size and lower production cost, and the battery prepared by the lithium ferrous phosphate has high specific capacity of charging for the first time and good 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, very stable charging and discharging platform, stable structure during charging and discharging, and has the advantages of non-toxic, non-polluting, good safety performance, can be used in high temperature environment, and has a wide range...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/58H01M4/48H01M4/04C01B25/45
CPCY02T10/7011Y02E60/10
Inventor 贾文雯徐茶清陈小勇
Owner BYD CO LTD
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