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Ferrous phosphate hydrated salt crystal, producing method thereof and method for producing Li-Fe-P composite oxides

A composite oxide and ferrous phosphate technology, applied in the direction of phosphorus compounds, iron compounds, chemical instruments and methods, etc., can solve the problems of developed crystallization, difficult processing such as crushing, and difficult expansion

Inactive Publication Date: 2003-08-13
NIPPON CHECMICAL IND CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0015] However, the ferrous phosphate hydrate obtained by this method has an average particle size of 7 μm to tens of μm, and the crystals of the particles are developed and very hard.
[0016] Therefore, there are disadvantages that the reactivity is poor and processing such as pulverization is difficult
As a result, it is difficult to expand the use of LiFePO as a positive electrode active material for lithium batteries. 4 Applications of raw materials for the production of representative functional inorganic materials

Method used

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  • Ferrous phosphate hydrated salt crystal, producing method thereof and method for producing Li-Fe-P composite oxides
  • Ferrous phosphate hydrated salt crystal, producing method thereof and method for producing Li-Fe-P composite oxides
  • Ferrous phosphate hydrated salt crystal, producing method thereof and method for producing Li-Fe-P composite oxides

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0105] Dissolve 907g (3mol) of ferrous sulfate heptahydrate (FeSO 4 ·7H 2 O) and 261g (2mol) of 75% phosphoric acid (H 3 PO 4 ) to make a mixed solution (temperature 17°C, pH 1.6). 1500 ml (6 mol) of 16% sodium hydroxide (NaOH) aqueous solution was dropped into the mixed solution over 18 minutes at a rate of 83 ml / min to precipitate ferrous phosphate (temperature 31° C., pH 6.7).

[0106] Next, ferrous phosphate was recovered by filtration, and the recovered ferrous phosphate was carefully washed with 4.5 L of water.

[0107] Next, the washed ferrous phosphate was dried at a temperature of 50° C. for 23 hours to obtain 490 g of a dry product. The resulting dried product was analyzed by X-ray diffraction. As a result, the diffraction pattern was consistent with JCPDS (Joint Committee on Powder Diffraction Standards) figure number 30-662, so it was confirmed that the dried product was Fe 3 (PO 4 ) 2 ·8H 2 O (98% yield).

[0108] The resulting Fe is shown in Table 2 3 (...

Embodiment 2

[0112] Dissolve 816g (2.7mol) of ferrous sulfate heptahydrate (FeSO 4 ·7H 2 O) and 261g (2mol) of 75% phosphoric acid (H 3 PO 4 ) to make a mixed solution (temperature 8°C, pH 0.6). 1000 ml (6 mol) of 24% sodium hydroxide (NaOH) aqueous solution was dropped into the mixed solution over 6 minutes at a rate of 166 ml / min to precipitate ferrous phosphate (temperature 21° C., pH 7.4).

[0113] Next, ferrous phosphate was recovered by filtration, and the recovered ferrous phosphate was carefully washed with 4.5 L of water.

[0114] Next, the washed ferrous phosphate was dried at a temperature of 50° C. for 23 hours to obtain 480 g of a dry product. The obtained dried product was analyzed by X-ray diffraction. As a result, the diffraction pattern was consistent with JCPDS (Joint Committee on Powder Diffraction Standards) figure No. 30-662, so it was confirmed that the dried product was Fe 3 (PO 4 ) 2 ·8H 2 O (94% yield).

[0115] The resulting Fe is shown in Table 2 3 (PO ...

Embodiment 3

[0130] The ferrous phosphate hydrate crystallization (Fe 3 (PO 4 ) 2 ·8H 2 O), 2.4kg lithium phosphate (Li 3 PO 4 , average particle diameter 5.8 μm, manufactured by FMC Corporation) and 1 kg of highly conductive carbon black with a particle diameter of 0.05 μm (manufactured by Ketsutian Black Inta-Nashional Corporation, trade name ECP) ​​were fully mixed. Next, the mixture is pulverized using a dry bead milling device to obtain a reaction primary product. Table 3 shows the main physical properties of the reaction precursors obtained.

[0131] In addition, put 10 g of the sample into a 50 ml measuring cylinder, fix it on the dual automatic vibration (DUAL AUTOTAP) device manufactured by "YUASA-IONICS Co., Ltd.", and after vibration 500 times, read the volume, according to the following formula Calculate the specific volume of the bead mill pulverized product.

[0132] 【Mathematical formula 2】

[0133] Specific volume (ml) = V / F

[0134] (In the formula, F represen...

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Abstract

PROBLEM TO BE SOLVED: To prepare a fine ferrous phosphate hydrate crystal excellent in processability and suitable as a raw material for producing a functional inorganic material, particularly that for LiFePO<SB>4< / SB>or LiFeMePO<SB>4< / SB>(Me is at least one metal element selected from Mn, Co, Ni and Al) to be used for the positive material of a lithium secondary battery, and to provide a method for industrially advantageously producing the above crystal in a high yield and a production method for a lithium / iron / phosphorus-based complex oxide using the crystal.SOLUTION: The ferrous phosphate hydrate crystal is represented by the formula: Fe<SB>3< / SB>(PO<SB>4< / SB>)<SB>2< / SB> / 8H<SB>2< / SB>O and has an average particle size of 5 μm or less. It is preferable that the crystal has a half value width of a diffraction peak in a lattice place (020 plane) obtained by an X-ray diffraction analysis of ≥0.20°.

Description

technical field [0001] The present invention relates to the use as a raw material for the production of functional inorganic materials, especially LiFePO used as a positive electrode active material for lithium storage batteries 4 or LiFeMePO 4 (Me represents at least one or more metal elements selected from Mn, Co, Ni, and Al) Ferrous phosphate hydrate crystal useful as raw material for production, method for producing same, and production of lithium-iron-phosphorus composite oxide method. Background technique [0002] In recent years, as home appliances have become more portable and wireless, lithium ion storage batteries have been put into practical use as power sources for small electronic devices such as laptop personal computers, mobile phones, and video cameras. Regarding this lithium-ion storage battery, since Mizushima et al. proposed in 1980 that lithium cobalt oxide is useful as a positive electrode active material for lithium-ion storage batteries ["Materialuri...

Claims

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Application Information

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IPC IPC(8): C01B25/37C01G49/00H01M4/36H01M4/58H01M10/052
CPCY02E60/10C01B25/37C01G49/00H01M4/36H01M4/5825H01M10/052
Inventor 木下真之仲冈泰裕山崎信幸根岸克幸
Owner NIPPON CHECMICAL IND CO LTD
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