Preparation method for lithium iron phosphate

A technology of lithium ferrous phosphate and high-purity phosphoric acid, applied in chemical instruments and methods, phosphorus compounds, inorganic chemistry, etc., can solve the problems of low bulk density and low conductivity of lithium ferrous phosphate, and improve sphericity and bulk density , good fluidity and processability, and simple process

Active Publication Date: 2012-08-29
李全东 +2
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is to overcome the shortage of low bulk density and low conductivity of lithium ferrous phosphate in the prior art, and to provide a preparation method of lithium ferrous phosphate

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] Embodiment 1: a kind of preparation method of lithium ferrous phosphate comprises the following steps:

[0019] (1) Take 0.1 mole of high-purity phosphoric acid, slowly add 0.1 mole of refined battery-grade ferric oxalate dihydrate, mix well, then add 0.06 mole of lithium hydroxide monohydrate, adjust the pH value to 5.5, and place it in a colloid mill for 2 hours Until the mixture is uniform, a high-density spherical ferrous phosphate and lithium ferrous phosphate mixed precursor is synthesized. After drying at 65°C, place it in a reaction furnace, raise the temperature to 350°C at a rate of 5°C / h, keep it warm for 3 hours, and then cool to room temperature.

[0020] (2) Take out the mixture obtained in step (1) and pulverize it, blend it with lithium hydroxide, carbon source, and metal oxide, and control the proportion of the main components according to Fe?Li?PO 4 =1?1?1, the carbon source (graphite: sucrose mass ratio = 1:3) accounts for 16% by weight of the mixtur...

Embodiment 2

[0022] Embodiment 2: a kind of preparation method of lithium ferrous phosphate comprises the following steps:

[0023] The mass ratio of graphite to sucrose in the carbon source is 1:4, the mass ratio of Sr metal oxide to Zr metal oxide in the composite metal oxide is 1:2, and other steps and process parameters are the same as in Example 1.

[0024] The average particle size of lithium iron phosphate product is 6.2μm, and the tap density is 1.78g / cm 3 At room temperature, the first discharge specific capacity at 0.2C rate is 154mAh / g, the first discharge specific capacity at 1C rate is 142mAh / g, and the reversible capacity after 100 cycles at various rates is 135mAh / g.

Embodiment 3

[0025] Embodiment 3: a kind of preparation method of lithium ferrous phosphate comprises the following steps:

[0026] The composite metal oxide is Ni oxide and Mo oxide with a mass ratio of 1:2, and other steps and process parameters are the same as in Example 1.

[0027] The average particle size of lithium iron phosphate product is 7.8μm, and the tap density is 1.76g / cm 3 At room temperature, the first discharge specific capacity at 0.2C rate is 156mAh / g, the first discharge specific capacity at 1C rate is 145mAh / g, and the reversible capacity after 100 cycles at various rates is 138mAh / g.

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Abstract

The invention discloses a preparation method for lithium iron phosphate. The method comprises the following steps: mixing high-purity phosphoric acid, lithium hydroxide and ferric oxalate; regulating the pH value to 5.0-6.0; drying the mixture at the temperature of 60-80 DEG C; heating the dried mixture to 300-400 DEG C at a rate of 5 DEG C / h in a reacting furnace; carrying out insulation reaction for 3 hours, and then cooling to room temperature; smashing the obtained mixture; evenly mixing the smashed mixture with lithium hydroxide, a carbon source and metallic oxides by a ball mill, and utilizing a colloid mill to pulp the blend at the temperature of 16-20 DEG C for 6-10 hours; and drying at the temperature of 60-80 DEG C, and sintering at the temperature of 600-800 DEG C for 3-6 hoursin the reacting furnace in the presence of inert gas, thus preparing the lithium iron phosphate product. The preparation method is smart in concept and simple in process; and by means of the method, the stacking density and electrical conductivity of the lithium iron phosphate can be effectively improved.

Description

technical field [0001] The invention belongs to the technical field of batteries, and relates to a preparation method of lithium ferrous phosphate. Background technique [0002] In recent years, lithium iron phosphate, the cathode material of lithium-ion batteries, is mainly used in power lithium-ion batteries as the cathode active material. Since 1996 Japan's NTT first revealed AMPO 4 (A is an alkali metal, M is a combination of Co and Fe) Lithium battery anode materials with an olivine structure, in 1997, researchers such as John.B.Goodenough of Texas State University also reported LiFePO 4 The characteristics of reversibly moving in and out of lithium, the United States and Japan have simultaneously published olivine structure (LiMPO 4 ), making the material has received great attention, and caused extensive research and rapid development. Compared with traditional lithium-ion secondary battery cathode materials (spinel-structured LiMn 2 o 4 and layered LiCoO 2 ) co...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B25/45
Inventor 李全东肖遥王文武
Owner 李全东
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