Method for preparing lithiumion cell positive material Iron-lithium phosphate

A lithium-ion battery, lithium iron phosphate technology, applied in the direction of electrode manufacturing, battery electrodes, secondary batteries, etc., can solve problems such as difficulties, and achieve the effects of no three wastes discharge, simple and easy-to-operate process, and simple and easy methods

Active Publication Date: 2005-02-16
SHANGHAI SINOPOLY JIAHUA BATTERY TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, pure Fe was prepared by liquid phase deposition 3 (PO 4 ) 2 ·8H 2 O is more difficult

Method used

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  • Method for preparing lithiumion cell positive material Iron-lithium phosphate
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  • Method for preparing lithiumion cell positive material Iron-lithium phosphate

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] 2.86 grams (0.05 moles) of iron powder, 15.1 grams (0.1 moles) of iron phosphate, 6.37 grams (0.05 moles) of lithium phosphate and 2.25 grams of sucrose were mixed evenly. The mixture was placed in an agate jar filled with argon and ball milled for 24 h. The ball-milled product was placed in a high-temperature furnace, heated at a heating rate of 10°C / min in an argon atmosphere, and fired at a constant temperature of 600°C for 30 minutes, and then cooled to room temperature at a cooling rate of 20°C / min to obtain LiFePO 4 / C powder. figure 1 X-ray diffraction analysis results show that the prepared lithium iron phosphate powder is olivine-type LiFePO 4 Single-phase structure, there is no impurity peak in the spectrum, and the product has high purity. figure 2 is LiFePO 4 / C powder magnified 5000 times electron micrograph, the particle size of the product is basically less than 5 microns.

[0031] Weigh 0.8 g of the obtained lithium iron phosphate powder, add 0.1 g ...

Embodiment 2

[0034] 78 g Mn(NH 4 ) 2 (SO 4 ) 2 .6H 2 O and 23 g NH 4 h 2 PO 4 Dissolve in 1000ml of deionized water, after mixing the two solutions, add 8ml of 30% H 2 o 2 aqueous solution, stirring was continued for 2 hours. The resulting precipitate was filtered, washed, dried, and then calcined at 400 °C for 4 hours to obtain MnPO 4 . 2.86 grams (0.05 moles) of iron powder, 8.31 grams (0.055 moles) of FePO 4 , 6.75 grams (0.045 moles) of MnPO 4 and 6.37 g (0.05 mol) Mix with 2.25 grams of sucrose, prepare LiFe by the method of embodiment 1 0.7 mn 0.3 PO 4 / C powder. When the obtained product is discharged at a rate of 0.2C, the specific capacity is about 146mAh / g, and the discharge curve voltage is 3.8V-2.9V.

Embodiment 3

[0036] Weigh 41 grams of Ni(NH 4 ) 2 (SO 4 ) 2 .6H 2 O and 12 g NH 4 h 2 PO 4 Dissolve in 500ml of deionized water respectively, after mixing the two solutions, add 4ml of 30% H 2 o 2 aqueous solution, stirring was continued for 2 hours. The resulting precipitate was filtered, washed and dried, and then calcined at 400°C for 4 hours to obtain NiPO 4 crystals. 2.86 grams (0.05 moles) of iron powder, 12.84 grams (0.085 moles) of FePO 4 , 2.31 grams (0.015 moles) NiPO 4 and 6.37 g (0.05 mol) Mix with 0.8 gram of acetylene black, prepare LiFe by the method of embodiment 1 0.9 Ni 0.1 PO 4 / C powder. The specific capacity of the obtained product is about 143mAh / g when discharged at a rate of 0.2C, and the discharge voltage is about 3.45V.

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Abstract

Mechanical solid phase method for synthesizing lithium ferric phosphate includes following steps: mixing iron powder, ferric phosphate, lithium phosphate, doping elements of phosphate, conducting agent or predecessor of conducting agent according to proportion evenly; placing the mixed admixture into ball milling container with inert gases being filled and ball milling for 18-36 hours; then putting the produced result from ball milling into high-temperature furnace with inert gases such as nitrogen gas and argon gas being filled; heating up in 10-30 deg.C / minute heating rate, baking at constant temperature 450-750 deg.C for 10-60 minutes; then cooling at 10-30 deg.C / minutes cooling rate, cooling the admixture to room temperature so as to obtain powder of lithium ferric phosphate or powder of doped powder of lithium ferric phosphate. Advantages are: feasible, no pollution, high specific capacity and good cycle performance.

Description

Technical field: [0001] The invention belongs to a method for preparing a cathode material of a lithium ion battery, in particular to a method for preparing lithium iron phosphate, an anode material of a lithium ion battery, by adopting a mechanical solid-phase synthesis process. Background technique: [0002] LiFePO was first reported by A.K.Padhi in 1997 4 Since it has the function of intercalating lithium, the olivine-type phosphate lithium intercalating material, LiMPO4 (M: Mn, Fe, Co, Ni), has attracted much attention as a promising cathode material for lithium-ion batteries. Among them, LiFePO4 with a theoretical capacity of 170mAh / g is considered to be the most promising cathode material for lithium-ion batteries due to its rich iron resources, low price, excellent thermal stability and environmental friendliness. [0003] At present, the methods for synthesizing lithium iron phosphate include high-temperature solid-phase reaction method, liquid-phase co-deposition m...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B25/00C01D15/00C01G1/02H01M4/04H01M4/48H01M4/58H01M10/36
CPCH01M4/5825H01M10/0525Y02E60/10
Inventor 廖小珍马紫峰周锦鑫
Owner SHANGHAI SINOPOLY JIAHUA BATTERY TECH
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