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

A cathode active material, lithium ferrous phosphate technology, applied in the field of preparation of lithium ion secondary battery cathode active material lithium ferrous phosphate, can solve the problem of low discharge performance under high current, the battery cannot take into account high capacity, and lithium iron phosphate cannot Taking into account issues such as high mass specific capacity and volume specific capacity

Active Publication Date: 2010-12-22
BYD CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is to overcome the defect that the lithium iron phosphate prepared by the prior art cannot take into account high mass specific capacity and volume specific capacity, so that the prepared battery cannot take into account high capacity, good high-current discharge performance and small volume. , to provide a preparation method of lithium iron phosphate that makes the battery smaller and has high capacity and good high-current discharge performance at the same time

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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Embodiment 1

[0028] This embodiment illustrates the preparation of the positive electrode active material lithium iron phosphate provided by the invention

[0029] (1) 369.5 grams of Li 2 CO 3 , 798.5 g Fe 2 o 3 , 1150.2 g NH 4 h 2 PO 4 , 80 grams of graphite mixed with 2500 milliliters of absolute ethanol (Li: Fe: P molar ratio is 1: 1: 1), ball milled on a planetary ball mill for 0.5 hour, took out and dried;

[0030] (2) Under the protection of argon gas at 350° C. and a flow rate of 10 liters / min, the mixture in step (1) was sintered at a constant temperature for 6 hours, and naturally cooled to room temperature;

[0031] (3) The sintered product obtained in step (2) was continued to be high-energy ball milled on a planetary ball mill for 6 hours at a speed of 900 rpm, and the median particle diameter D of the obtained sintered product was 50 1.90 microns; D 95 7.74 microns; then briquette under a pressure of 5 MPa, so that the compacted density of the sintered product reaches ...

Embodiment 2

[0033] This embodiment illustrates the preparation of the positive electrode active material lithium iron phosphate provided by the invention

[0034] (1) 369.5 grams of Li 2 CO 3 , 758.5 ​​g Fe 2 o 3 , 20 grams of MgO, 1150.2 grams of NH 4 h 2 PO 4 , 228.6 grams of glucose mixed with 2500 milliliters of absolute ethanol (Li: Fe: Mg: P molar ratio is 1: 0.95: 0.05: 1), ball milled on a planetary ball mill for 0.5 hour, took out and dried;

[0035] (2) Under the protection of argon gas at 390°C and a flow rate of 10 liters / min, the mixture in step (1) was sintered at a constant temperature for 8 hours, and cooled naturally to room temperature;

[0036] (3) The sintered product obtained in step (2) was continued to be high-energy ball milled on a planetary ball mill for 8 hours at a speed of 900 rpm, and the median particle diameter D of the obtained sintered product was 50 1.89 microns; D 95 7.56 microns; then briquette under a pressure of 15 MPa, so that the compacted ...

Embodiment 3

[0038] This embodiment illustrates the preparation of the positive electrode active material lithium iron phosphate provided by the invention

[0039] (1) 419.6 g of LiOH·H 2 O, 798.5 g Fe 2 o 3 , 1150.2 g NH 4 h 2 PO 4 , 228.6 grams of glucose mixed with 3500 milliliters of absolute ethanol (Li: Fe: P molar ratio is 1: 1: 1), ball milled on a planetary ball mill for 0.5 hour, took out and dried;

[0040] (2) Under the protection of argon gas at 400°C and a flow rate of 8 liters / min, the mixture in step (1) was sintered at a constant temperature for 10 hours, and cooled naturally to room temperature;

[0041] (3) The median diameter D of the sintered product obtained by continuing the high-energy ball milling on the planetary ball mill for 10 hours with the sintered product obtained in step (2) at a speed of 1000 rpm 50 1.63 microns; D 95 6.52 microns; then briquette under a pressure of 18 MPa, so that the compacted density of the sintered product reaches 3.3 g / cm3; the...

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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 that 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 iron compound is ferric iron compound; the sintering method is carried out in inert atmosphere or reducing atmosphere; the mixture is sintered at a first constant sintering temperature, and the sintering product is acquired; the sintering product acquiredfrom sintering at the first sintering temperature is cooled to room temperature, ground and briquetted; the mixture is sintered at a second constant sintering temperature, and is cooled to room temperature in inert atmosphere or reducing atmosphere; the second sintering temperature is at least 100 DEG C higher than the first sintering temperature. The lithium iron phosphate acquired by the methodof the invention has relatively high specific discharge capacity and specific volumetric capacity, and the produced batteries have small size, high capacity and good discharge performance at high current, and the invention can combine the advantages of lithium iron phosphate prepared by taking ferrous iron and ferric iron as iron sources respectively, thus the performance can be remarkably improved.

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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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/58H01M4/48C01B25/45H01M4/04
CPCY02E60/10
Inventor 徐茶清肖峰陈小勇唐玉
Owner BYD CO LTD
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