Preparation method of LiFePO4/C modified ternary positive electrode material

A positive electrode material and modification technology, which is applied in the field of electrochemical material preparation, can solve problems such as cycle performance deterioration, battery capacity loss, and material electrochemical performance deterioration, and achieve high-rate discharge performance, capacity density, and contact area. big effect

Active Publication Date: 2016-02-24
SHANDONG GOLDENCELL ELECTRONICS TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although the ternary cathode material has many advantages above, due to the Ni 2+ with Li + The ionic radius is closer to the cation mixing phenomenon, which makes the material prone to lithium precipitation in the air, resulting in poor electrochemical performance of the material.
The main solution currently used is bulk doping of materials, but there are certain defects in doping: on the one hand, the doping of inactive material elements will lead to the loss of battery capacity; Spherical or quasi-spherical secondary particles are used. During the charging and discharging process of the battery, the surface of the secondary particles is in contact with the electrolyte, and the surface of the active particle of the positive electrode material is eroded by fluoride and dissolved by transition metal ions, resulting in the collapse of the surface structure and deterioration of cycle performance.

Method used

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  • Preparation method of LiFePO4/C modified ternary positive electrode material
  • Preparation method of LiFePO4/C modified ternary positive electrode material
  • Preparation method of LiFePO4/C modified ternary positive electrode material

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Experimental program
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Effect test

Embodiment 1

[0021] (1) Preparation of ternary cathode material precursor by co-precipitation method:

[0022] Prepare a mixed aqueous solution of nickel, cobalt and manganese, with a total concentration of 2.0mol / L, in which the molar ratio of the three metal salts is Ni:Co:Mn=1:1:1; prepare sodium hydroxide to 2.0mol / L, and prepare ammonia water The concentration is 2.0mol / L, the mixed salt solution, sodium hydroxide solution and ammonia water are flowed into the reaction kettle with a certain bottom liquid by three metering pumps respectively, and the flow rate of the mixed salt solution, precipitant and complexing agent is adjusted to make the reaction The pH value in the kettle was 10.5, the temperature in the reaction kettle was controlled at 35°C, and the dropping time was controlled at 15 hours. Finally, the reaction materials were washed and dried to obtain a spherical precursor with a particle size of 6 μm.

[0023] (2) Preparation of ternary cathode material:

[0024] Lithium c...

Embodiment 2

[0029] (1) Preparation of ternary cathode material precursor by co-precipitation method:

[0030] Prepare a mixed aqueous solution of nickel, cobalt and manganese, with a total concentration of 4.0mol / L, in which the molar ratio of the three metal salts is Ni:Co:Mn=0.8:0.1:0.1; prepare sodium hydroxide to 2.0mol / L, and prepare ammonia water The concentration is 2.0mol / L, the mixed salt solution, sodium hydroxide solution and ammonia water are flowed into the reaction kettle with a certain bottom liquid by three metering pumps respectively, and the flow rate of the mixed salt solution, precipitant and complexing agent is adjusted to make the reaction The pH value in the kettle was 12, the temperature in the reaction kettle was controlled at 35°C, and the dropping time was controlled at 15 hours. Finally, the reaction materials were washed and dried to obtain a spherical precursor with a particle size of 4 μm.

[0031] (2) Preparation of ternary cathode material:

[0032] Lithi...

Embodiment 3

[0037] (1) Preparation of ternary cathode material precursor by co-precipitation method:

[0038] Prepare a mixed aqueous solution of nickel, cobalt and manganese, with a total concentration of 2.0mol / L, wherein the molar ratio of the three metal salts is Ni:Co:Al=0.8:0.1:0.1; prepare sodium hydroxide to 2.0mol / L, and prepare ammonia water The concentration is 2.0mol / L, the mixed salt solution, sodium hydroxide solution and ammonia water are flowed into the reaction kettle with a certain bottom liquid by three metering pumps respectively, and the flow rate of the mixed salt solution, precipitant and complexing agent is adjusted to make the reaction The pH value in the kettle was 11.5, the temperature in the reaction kettle was controlled at 35°C, and the dropping time was controlled at 15 hours. Finally, the reaction materials were washed and dried to obtain a spherical precursor with a particle size of 8 μm.

[0039] (2) Preparation of ternary cathode material:

[0040] Lith...

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Abstract

The invention relates to a preparation method of a LiFePO4 / C modified ternary positive electrode material. Firstly, a ternary positive electrode material is prepared by a coprecipitation method; then a LiFePO4 / C composite material is grown on the surface of the ternary positive electrode material by a solid phase method, and the ternary positive electrode material is subjected to surface coating modification. The lithium iron phosphate active electrode material is adopted for modifying the ternary electrode material, on one hand, the advantages of the two active materials can be integrated to obtain the composite positive electrode material having better cycle performance, higher capacity and larger energy density; on the other hand, a traditional modification method for a ternary material is changed, and the cycle performance of the ternary positive electrode material is improved in the premise of almost no loss of material self capacity.

Description

technical field [0001] The invention relates to the field of preparation of electrochemical materials, in particular to a LiFePO 4 / C modified ternary cathode material preparation method. Background technique [0002] In today's society, lithium-ion batteries have become one of the research hotspots in the field of new secondary chemical battery power sources. Compared with traditional batteries, they have the advantages of high average discharge voltage, large volume specific capacity, and good cycle performance. The performance of lithium-ion secondary batteries mainly depends on its positive and negative active materials. [0003] LiFePO 4 It is a new type of cathode material for lithium-ion batteries. It has excellent charge-discharge platform, good cycle performance, low price, and environmental friendliness. It is considered to be the most promising cathode material for lithium-ion batteries. At present, it has been widely used in industrial production such as miner...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/505H01M4/525H01M4/58H01M10/0525
CPCH01M4/366H01M4/505H01M4/525H01M4/5825H01M10/0525H01M2004/021Y02E60/10
Inventor 关成善宗继月孟博张淑芳杜显振
Owner SHANDONG GOLDENCELL ELECTRONICS TECH
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