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

A cathode active material, lithium iron phosphate technology, applied in battery electrodes, chemical instruments and methods, circuits, etc., can solve the problems of low specific capacity, high battery internal resistance, lithium iron phosphate doping, etc., to achieve low internal resistance, good cycle performance, high capacity

Active Publication Date: 2012-05-02
BYD CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] In the prior art, in the reaction process of preparing lithium ferrous phosphate with ferrous salt as the reaction raw material, the inert gas must be continuously fed in for protection to prevent the ferrous salt from being oxidized, which not only consumes a large amount of inert gas, but also It is easy to make the prepared lithium iron phosphate doped with Fe 2 P heterophase, resulting in higher internal resistance and lower specific capacity of the battery prepared from the lithium iron phosphate

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

[0031] This embodiment illustrates the preparation of the positive electrode active material lithium iron phosphate provided by the invention

[0032] (1) 369 grams of Li 2 CO 3 , 1799 g FeC 2 o 4 2H 2 O. 1150 g NH 4 h 2 PO 4 Mix with 300 grams of glucose and 3000 grams of alcohol (Li:Fe:P molar ratio is 1:1:1), ball mill for 10 hours at a speed of 300 rpm, take it out, and dry it at 80°C;

[0033] (2) the mixture of step (1) is placed in a reaction vessel provided with an air inlet and an air outlet (the air inlet and the air outlet are on the same vertical plane, and the air inlet is down, and the air outlet is on the top), Open the gas outlet and the gas inlet, feed argon gas at a flow rate of 5 liters / minute, replace the air in the reaction vessel, then close the gas inlet, connect the gas outlet to the conduit and put the conduit into a 25°C Hydraulic oil (Caltex, special-grade hydraulic oil 460) (the conduit port is 5 cm below the hydraulic oil level), then heat ...

Embodiment 2

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

[0037] (1) 239.5 grams of LiOH, 1158.6 grams of FeCO 3 , 1319.7 grams (NH 4 ) 2 HPO 4 Mix 320 grams of glucose with 2700 grams of alcohol (Li: Fe: P molar ratio is 1:1:1), ball mill for 10 hours at a speed of 300 rpm, take it out, and dry at 80°C;

[0038] (2) the mixture of step (1) is placed in a reaction vessel provided with an air inlet and an air outlet (the air inlet and the air outlet are on the same vertical plane, and the air inlet is down, and the air outlet is on the top), Open the gas outlet and the gas inlet, feed argon gas at a flow rate of 5 liters / minute, replace the air in the reaction vessel, then close the gas inlet, connect the gas outlet to the conduit and put the conduit into a 25°C In the hydraulic oil (the conduit port is 5 cm below the hydraulic oil level), then heat up to 700 °C at a constant temperature f...

Embodiment 3

[0041] This embodiment illustrates the preparation of the positive electrode active material lithium iron phosphate provided by the invention

[0042] (1) 369 grams of Li 2 CO 3 , 1799 g FeC 2 o 4 2H 2 O. 1150 g NH 4 h 2 PO 4 Mix with 310 grams of sucrose and 3000 grams of alcohol (Li:Fe:P molar ratio is 1:1:1), ball mill for 10 hours at a speed of 300 rpm, take it out, and dry at 80°C;

[0043] (2) the mixture of step (1) is placed in a reaction vessel provided with an air inlet and an air outlet (the air inlet and the air outlet are on the same vertical plane, and the air inlet is down, and the air outlet is on the top), Open the gas outlet and the gas inlet, feed argon gas at a flow rate of 5 liters / minute, replace the air in the reaction vessel, then close the gas inlet, connect the gas outlet to the conduit and put the conduit into a 25°C In the hydraulic oil (the conduit port is 5 cm below the hydraulic oil level), then heat up to 750 °C at a constant temperature...

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Abstract

The invention discloses a preparation method of a lithium ferrous phosphate (LiFePO4) which is an anode active substance of a lithium-ion secondary battery. The method comprises the steps of: sintering a mixture containing a lithium compound, a ferro compound, a phosphorous compound and a carbon source additive in inert atmosphere, and then cooling the mixture to obtain sintering product, wherein, during sintering, the inert atmosphere is static and the pressure of the inert atmosphere is normal pressure. The LiFePO4 obtained by the preparation method does not contain Fe2P dephasign, and the batteries prepared by the LiFePO4 have high capacity, lower internal resistance 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 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. . Commercialized LiCoO 2 The positive electrode active material has high capacity and long cycle life. However, due to the scarcity of cobalt resources, high price and certain toxicity, it is an important research direction for lithium-ion batteries to find cheap, reliable, and environmentally friendly positive electrode active materials. LiNiO 2 、LiNi x co 1-x o 2 layered oxides and LiMnO 4 The representative spinel-type positive electrode active material has been extensively stu...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B25/45H01M4/58
CPCY02E60/12Y02E60/10
Inventor 席小兵荣强廖华栋韦建群
Owner BYD CO LTD
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