Method for preparing lithium ion battery anode material lithium iron phosphate

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. It can solve the problems affecting the performance of positive electrode materials and batteries, the inability to guarantee the complete reaction, and the reduction in the capacity of lithium iron phosphate. problems, to achieve the effect of easy industrial production, low cost, and less consumption of reducing agent

Active Publication Date: 2012-07-25
SHENZHEN BAK POWER BATTERY CO LTD
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  • Claims
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AI Technical Summary

Problems solved by technology

In the final lithium iron phosphate product in CN1800003A and CN1821062A, lithium phosphate miscellaneous items may remain, which reduces the capacity of lithium iron phosphate and affects the performance of positive electrode materials and batteries
In addition, in these three preparation methods of lithium ferrous phosphate, a large amount of reducing agent needs to be used to reduce the ferric iron in the raw material to ferrous iron; both ferric phosphate and ferrous phosphate are insoluble, and the reaction cannot be guaranteed to be complete. , the reaction speed is also relatively slow, CN1821062A also needs to use reducing hydrogen in the high-temperature roasting stage

Method used

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  • Method for preparing lithium ion battery anode material lithium iron phosphate

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] (1) Take by weighing phosphoric acid and ferrous sulfate according to molar ratio P:Fe=1:1, in N 2In the atmosphere, dissolve phosphoric acid and ferrous sulfate in distilled water, adjust the pH value with hydrochloric acid to make it 2.5-4, then add a small amount of hydroxylamine hydrochloride until the insoluble matter is dissolved by visual observation, then slowly add ammonia water and keep stirring until the pH When the value is 9, the solid phase material is obtained by filtration, washed and then dried, and the obtained material is the ferrous ammonium phosphate precursor. The whole preparation process of ferrous ammonium phosphate precursor is in N 2 carried out under the protection of the atmosphere. Sampling was carried out to analyze the content of P and Fe in the ferrous ammonium phosphate precursor.

[0028] (2) Combine ferrous ammonium phosphate precursor with Li 2 CO 3 , sucrose mixed (if the sampling analysis shows that P:Fe2 CO 3 The ratio of mol...

Embodiment 2

[0034] (1) the ferrous ammonium phosphate precursor obtained in step (1) in embodiment one and Li 2 CO 3 , diammonium hydrogen phosphate, TiCl 4 Mixed with glucose, ferrous ammonium phosphate precursor and Li 2 CO 3 、TiCl 4 The molar ratio with diammonium hydrogen phosphate is determined by making the final product Li:Fe:Ti:P=1:0.95:0.05:1, and the amount of glucose added is determined by the carbon content of 5wt% in the final product lithium ferrous phosphate after roasting. With distilled water as the dispersion medium, in N 2 Ball milling in atmosphere for 2 to 5 hours. N 2 Dry in atmosphere.

[0035] (2) Carry out the pre-baking and roasting process in the same method as in Example 1 to obtain carbon-coated lithium ferrous phosphate (doped with titanium). The fabrication and electrochemical performance testing of practical batteries and button batteries were carried out in the same manner as in Example 1.

[0036] The electrochemical properties of the materials a...

Embodiment 3

[0038] (1) Take by weighing phosphoric acid, ferrous chloride and magnesium chloride by molar ratio P:Fe:Mg=1:0.95:0.05, in N 2 In the atmosphere, dissolve phosphoric acid, ferrous ammonium sulfate and magnesium chloride in distilled water, adjust the pH value to 2.5-4 with hydrochloric acid, and then add a small amount of ascorbic acid until the insoluble matter is dissolved by visual observation. Add ammonia water slowly and keep stirring until the pH value is 8. The solid phase material is obtained by filtration, the solid phase material is washed and then dried, and the obtained material is the ferrous ammonium phosphate precursor. This preparation process of ferrous ammonium phosphate precursor is in N 2 carried out under the protection of the atmosphere. Sampling was carried out to analyze the content of P and Fe in the ferrous ammonium phosphate precursor.

[0039] (2) Combine the obtained ferrous ammonium phosphate precursor with Li 2 CO 3 Mix with dextrin (if the...

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Abstract

The invention discloses a preparation method for the anode material of a lithium ion battery, namely, ferrous phosphate lithium. The method comprises the following steps: firstly, a soluble ferrous iron source is used for preparing a ferrous phosphate ammonium precursor in an inert atmosphere, and then the ferrous phosphate ammonium precursor, Li2CO3 and a carbon source are preroasted, tabletted and roasted to obtain carbon-coated ferrous phosphate lithium. By adopting the preparation method, the generation of the lithium phosphate impurity phase can be inhibited, and the specific capacity of the ferrous phosphate lithium can be greatly enhanced; expensive oxidant and reducing gas are not required to be consumed, therefore, the cost is low, and the operation is convenient; when necessary, the amount of the required reducing agent is also very small; the material presents excellent circulation performance and specific capacity, the technique is simple, the cost is low, the cycle is short, and the uniformity of the material in one batch is good, which is convenient for doping, therefore, the invention is especially suitable for industrialized production.

Description

technical field [0001] The invention relates to a preparation method of lithium ferrous phosphate, a cathode material of a lithium ion battery, in particular to a preparation method of lithium ferrous phosphate capable of suppressing the generation of lithium phosphate heterophases and greatly increasing the specific capacity of lithium ferrous phosphate. Background technique [0002] As a clean and green energy source, lithium-ion batteries have the characteristics of large capacity and high power, and are mainly used in small devices, especially mobile phones, laptop computers, and portable electric tools. Lithium-ion batteries are generally composed of battery cover components, battery casings, electrolytes, and battery cells wound by positive and negative electrodes and separator paper. Wherein the positive electrode sheet is coated with a positive electrode active material, and the negative electrode sheet is coated with a negative electrode active material. The proper...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/58H01M4/48H01M4/04C01B25/45
CPCY02E60/10
Inventor LIU YUPINGOUYANG XISUN HONGFEIPENG ZHONGYONGWAN LICHENGLI QI
Owner SHENZHEN BAK POWER BATTERY CO LTD
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