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A method for making anode material LiFePO4 of lithium ion battery

A technology for lithium iron phosphate and lithium ion batteries, which is applied in the direction of electrode manufacturing, battery electrodes, chemical instruments and methods, etc., and can solve the limitations of large-scale industrialization of lithium iron phosphate, poor high-current discharge capacity of synthetic materials, and control conditions Harsh and other problems, to achieve the effect of reducing synthesis cost, good high current, and short synthesis cycle

Inactive Publication Date: 2008-09-10
CENT SOUTH UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, these methods have some inherent disadvantages, such as: high synthesis temperature, long synthesis cycle, harsh control conditions, high cost, and poor high-current discharge capacity of the synthesized materials, which limit the large-scale industry of lithium iron phosphate change

Method used

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  • A method for making anode material LiFePO4 of lithium ion battery
  • A method for making anode material LiFePO4 of lithium ion battery
  • A method for making anode material LiFePO4 of lithium ion battery

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Effect test

Embodiment 1

[0019] Ferric phosphate, lithium carbonate, malic acid are used as raw materials, mixed uniformly in a molar ratio of 1:0.5:1, and mechanically activated for 0.5 hours; then loaded into a tube furnace, under an argon atmosphere, the temperature is 300 ° C, ℃, 560℃, 700℃ for 12 hours. The obtained material is analyzed by X-ray diffraction as an olivine structure, and the space group is Pnma, which is LiFePO 4 Structure. The particle size of the product obtained by SEM is about 200nm. The obtained products were assembled into button batteries to measure their charge-discharge specific capacity and cycle performance. Charge and discharge were carried out at a rate of 0.1C. Their initial discharge capacity and discharge capacity after 50 cycles are shown in Table 1.

[0020] Experimental condition and result of table 1 embodiment 1

[0021]

Embodiment 2

[0023] Ferric nitrate, lithium formate, triammonium phosphate, and mandelic acid are used as raw materials, mixed uniformly in a molar ratio of 1:1:1:3, and mechanically activated for 20 hours; then put into a tube furnace, under a hydrogen atmosphere, the temperature Keep the temperature at 600°C for 2 hours, 5 hours, 8 hours, and 20 hours, respectively. The obtained material is analyzed by X-ray diffraction as an olivine structure, and the space group is Pnma, which is LiFePO 4 Structure. The particle size of the product obtained by SEM is about 200nm. The obtained products were assembled into button batteries to measure their charge-discharge specific capacity and cycle performance. Charge and discharge were carried out at a rate of 0.1C. Their initial discharge capacity and discharge capacity after 50 cycles are shown in Table 2.

[0024] Experimental condition and result of table 2 embodiment 2

[0025]

Embodiment 3

[0027] Using iron carbonate, lithium oxide, diammonium hydrogen phosphate, and oxalic acid as raw materials, mix them uniformly in a molar ratio of 1:1:2:4, and mechanically activate them for 8 hours; then put them into a tube furnace, and under a nitrogen atmosphere, The temperature was kept at 560°C for 15 hours. The obtained material is analyzed by X-ray diffraction as an olivine structure, and the space group is Pnma, which is LiFePO 4 Structure. The obtained product was assembled into a button battery to measure its charge-discharge specific capacity and cycle performance, and the charge-discharge was carried out at a rate of 0.1C, and the initial discharge capacity was 165mAh·g -1 , the discharge capacity after 50 cycles is 165mAh·g -1 .

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Abstract

The invention discloses a preparation method of lithium iron phosphate, a material for positive electrode of lithium ion battery. The preparation method comprises the steps that: ferric iron compound, phosphorus compound and lithium compound are taken as raw materials and mixed according to molar ratio of the contained iron, phosphorus and lithium 1:1:1; the obtained mixture is evenly mixed under room temperature, and then mechanical activation is carried out; after 0.5-20 hours of activation, a reducing agent is added with the molar ratio of the reducing agent and the iron compound is 1:1-1:6; under normal temperature and pressure, the ferric iron is reduced by the reducing agent, so as to produce fine particles of LiFePO4 which is then sent into non oxidizing gas to be heated to 300-700 DEG C and calcined for 2-20 hours under constant temperature; finally, the lithium iron phosphate is obtained. The preparation method of lithium iron phosphate adopts low-temperature method to process the amorphous lithium iron phosphate so as to produce the lithium iron phosphate with excellent performance, which greatly reduces energy consumption and cost.

Description

technical field [0001] The invention relates to a preparation method of lithium ferrous phosphate, a cathode material of a lithium ion battery. Background technique [0002] LiFePO 4 It is a new type of cathode material for lithium-ion batteries. It has excellent charge and discharge platform, good cycle performance, low price, high theoretical capacity, and environmental friendliness. It is considered to be the most promising cathode material for lithium-ion batteries and is expected to be used in lithium-ion batteries On electric vehicles, its prospects are immeasurable. [0003] The traditional preparation methods mainly include the following: high temperature solid phase sintering method, carbothermal reduction method, sol-gel method, co-precipitation method, hydrothermal method and so on. However, these methods have some inherent disadvantages, such as: high synthesis temperature, long synthesis period, harsh control conditions, high cost, and poor high-current disch...

Claims

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Application Information

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IPC IPC(8): H01M4/58H01M4/48H01M4/04C01B25/45C01D15/00
CPCY02E60/10
Inventor 李新海郑俊超王志兴郭华军胡启阳彭文杰伍凌张云河刘久清符芳铭
Owner CENT SOUTH UNIV
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