A method for making anode material LiFePO4 of lithium ion battery

A lithium ferrous phosphate, lithium-ion battery technology, applied in electrode manufacturing, battery electrodes, chemical instruments and methods, etc., can solve the limitations of large-scale industrialization of lithium ferrous phosphate, poor high-current discharge capability 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: 2010-08-04
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

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] Using iron phosphate, lithium carbonate and malic acid as raw materials, the molar ratio of 1:0.5:1 is mixed uniformly, and mechanically activated for 0.5 hours; then it is put into a tube furnace, and the temperature is 300℃ and 500℃ respectively under argon atmosphere. Constant temperature at ℃, 560℃, 700℃ for 12 hours. The obtained material has an olivine structure by X-ray diffraction analysis, and the space group is Pnma, which is LiFePO 4 Structure. The particle size of the product can be obtained by SEM at about 200nm. The resulting products were assembled into button batteries to test their charge-discharge specific capacity and cycle performance. They were charged and discharged at a rate of 0.1C. Their first discharge capacity and discharge capacity after 50 cycles are shown in Table 1.

[0019] Table 1 Experimental conditions and results of Example 1

[0020]

Embodiment 2

[0022] Using ferric nitrate, lithium formate, triamine phosphate, and mandelic acid as raw materials, mix homogeneously at a molar ratio of 1:1:1:3, and mechanically activate for 20 hours; then put it into a tube furnace, under hydrogen atmosphere, temperature Keep at 600°C for 2 hours, 5 hours, 8 hours, and 20 hours. The obtained material has an olivine structure by X-ray diffraction analysis, and the space group is Pnma, which is LiFePO 4 Structure. The particle size of the product can be obtained by SEM at about 200nm. The resulting products were assembled into button batteries to test their charge-discharge specific capacity and cycle performance. They were charged and discharged at a rate of 0.1C. Their first discharge capacity and discharge capacity after 50 cycles are shown in Table 2.

[0023] Table 2 Experimental conditions and results of Example 2

[0024]

Embodiment 3

[0026] Using iron carbonate, lithium oxide, diammonium hydrogen phosphate, and oxalic acid as raw materials, mix homogeneously with a molar ratio of 1:1:2:4, and mechanically activate for 8 hours; then put it into a tube furnace, under a nitrogen atmosphere, The temperature is kept at 560°C for 15 hours. The obtained material has an olivine structure by X-ray diffraction analysis, and the space group is Pnma, which is LiFePO 4 Structure. Assemble the obtained product into a button cell to test its charge-discharge specific capacity and cycle performance, charge and discharge at a rate of 0.1C, the first discharge capacity is 165mAh·g -1 , Discharge capacity 165mAh·g after 50 cycles -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 underroom 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 300-700DEG 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 iron phosphate as a positive electrode material of a lithium ion battery. Background technique [0002] LiFePO 4 It is a new type of lithium ion battery cathode material. It has excellent charging and discharging platform, good cycle performance, low price, high theoretical capacity, environmental friendliness and other advantages. It is considered to be the most promising cathode material for lithium-ion batteries and is expected to be used in lithium-ion batteries. The prospect of electric vehicles is 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 shortcomings, such as: high synthesis temperature, long synthesis cycle, harsh control conditions, high cost, and poor high-...

Claims

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Application Information

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Patent Type & Authority Patents(China)
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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