Preparation method of lithium iron phosphate/carbon composite material

A technology of carbon composite materials and lithium iron phosphate, applied in electrical components, electrochemical generators, battery electrodes, etc., can solve the problems of poor electrochemical performance and high rate discharge performance of lithium iron phosphate materials, and achieve easy realization, Improved electrochemical performance and high production efficiency

Inactive Publication Date: 2019-05-10
ZHEJIANG NARADA POWER SOURCE CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Therefore, the electrochemical performance of the prepared lithium iron phosphate material is poor, and the high-rate discharge performance is poor.

Method used

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  • Preparation method of lithium iron phosphate/carbon composite material
  • Preparation method of lithium iron phosphate/carbon composite material
  • Preparation method of lithium iron phosphate/carbon composite material

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] (1) Ferric oxide, lithium carbonate, and phosphoric acid are mixed in molar ratio n(Fe):n(PO 4 ):n(Li)=0.98:1.02:1 and malonic acid accounting for 4% of the mass of ferric oxide and glucose calculated as 3% of the theoretical carbon content are added to deionized water, and mixed to form a solid content of 30% slurry and disperse for 60 minutes.

[0027] (2) Put the slurry obtained in step (1) into a sand mill and grind for 45 minutes to obtain a slurry with D50=0.287 microns.

[0028] (3) The slurry obtained in step (2) is passed through a two-phase flow spray dryer, and the inlet is set at 235° C., and the outlet is set at 90° C. for drying and granulation.

[0029] (4) Sinter the powder obtained in step (3) under the protection of nitrogen according to the system of 400°C for 3 hours and 700°C for 3 hours to obtain an average discharge capacity of 130mAh / g at 1C and an average discharge capacity of 115mAh / g at 5C. g of lithium iron phosphate products.

Embodiment 2

[0031] (1) Ferric hydroxide and lithium dihydrogen phosphate are molar ratio n(Fe):n(PO 4 ):n(Li)=0.98:1:1 and citric acid of 8% of the mass of ferric hydroxide and sucrose calculated on the basis of theoretical carbon content of 3% were added to deionized water and mixed into a slurry with a solid content of 35% And disperse for 120min.

[0032] (2) Put the slurry obtained in step (1) into a sand mill and grind for 30 minutes to obtain a slurry with D50=0.455 μm.

[0033] (3) The slurry obtained in step (2) is passed through a two-phase flow spray dryer, and the inlet is set at 260° C., and the outlet is set at 105° C. for drying and granulation.

[0034] (4) Sinter the powder obtained in step (3) under the protection of nitrogen according to the system of 350°C for 4 hours and 730°C for 1 hour to obtain an average discharge capacity of 122mAh / g at 1C and an average discharge capacity of 100mAh / g at 5C. g of lithium iron phosphate products.

Embodiment 3

[0036] (1) Ferric oxyhydroxide, lithium hydroxide, phosphoric acid in molar ratio n(Fe):n(PO 4 ):n(Li)=0.985:1.03:1 and 3% tartaric acid of iron oxyhydroxide mass and cyclodextrin calculated as 2% of theoretical carbon content are added to deionized water, and mixed into a slurry with a solid content of 25% material and disperse for 60 minutes.

[0037] (2) D50 of the slurry obtained in step (1)=0.649 μm, directly enters the spray drying process.

[0038] (3) The slurry obtained in step (2) is passed through a centrifugal spray dryer, with the inlet at 265°C and the outlet at 95°C for drying and granulation.

[0039] (4) Sinter the powder obtained in step (3) under the protection of nitrogen according to the system of 430°C for 3 hours and 690°C for 2 hours to obtain an average discharge capacity of 129mAh / g at 1C and an average discharge capacity of 108mAh / g at 5C. g of lithium iron phosphate products.

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Abstract

The invention provides a preparation method of a lithium iron phosphate/carbon composite material. The preparation method comprises the steps of pulping and dispersing, grinding, drying and granulating and sintering. The pulping and dispersing step comprises the steps that an iron source, a lithium source, a phosphorus source, a carbon source and a polycarboxylic acid are added into a solvent to be mixed into slurry, and dispersion is carried out, wherein the dispersion time is 30 minutes to 6 hours, and the adding amount of the carbon source is 1%-7% of the mass percentage of carbon in the lithium iron phosphate/carbon composite material; the grinding step comprises the steps that the dispersed slurry is grinded to a setting particle size, and if the particle size of the dispersed slurryis less than or equal to the set particle size, the next step is directly carried out; the drying and granulating step comprises the step that the slurry is dried and granulated by a spray drying method to obtain powder materials; and the sintering step comprises the step that the powder materials are sintered in inert gas to obtain the lithium iron phosphate/carbon composite material.

Description

technical field [0001] The invention relates to the technical field of lithium ion battery electrode materials, in particular to a preparation method of lithium iron phosphate / carbon composite material. Background technique [0002] Lithium-ion batteries have become the preferred power source for portable electronic devices such as mobile phones and notebook computers due to their outstanding advantages such as high working voltage, high specific capacity, small self-discharge, good cycle performance, long service life, light weight, and small size. In recent years, with the increasingly serious environmental problems, the application of lithium-ion batteries in vehicles with low exhaust emissions such as electric vehicles and hybrid vehicles has attracted more and more attention. higher requirements. [0003] As an important part of lithium-ion batteries, the research on cathode materials has always been the focus of people's research. As early as 1997, it was discovered ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/58H01M4/62H01M10/0525
CPCY02E60/10
Inventor 陈峰于文志相佳媛蒋岚
Owner ZHEJIANG NARADA POWER SOURCE CO LTD
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