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Method for preparing reduction carbon nano tube coated lithium iron phosphate cathode material

A technology of lithium iron phosphate and positive electrode materials, applied in battery electrodes, electrical components, circuits, etc., can solve the problems of difficult control of nanotube growth efficiency, uneven distribution of carbon nanotubes, unstable electrochemical performance, etc., and achieve discharge Elevated voltage platform, simple preparation process, and good cycle performance

Active Publication Date: 2014-11-05
贵州唯特高新能源科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Due to the uneven distribution of carbon transported in the gas phase on the sample, the growth efficiency of nanotubes grown from carbon sources is difficult to control, and the grown nanotubes may not be in good contact with the lithium iron phosphate composite material, resulting in poor electrochemical performance of the prepared samples. Instability, and in the preparation of the sample, the carbon nanotubes will be unevenly distributed on the lithium iron phosphate, and there are shortcomings such as unstable batch performance of the prepared sample

Method used

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  • Method for preparing reduction carbon nano tube coated lithium iron phosphate cathode material
  • Method for preparing reduction carbon nano tube coated lithium iron phosphate cathode material

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] 1) Preparation of carbon compounds

[0031] Mix citric acid and ethylene glycol according to the molar ratio of 1:4, stir at 45°C for 2h; place under the conditions of pressure 10Pa, temperature 125°C and stir for 5h to carry out polymerization reaction; dry. Ethylene glycol that did not participate in the polymerization reaction was removed to obtain a brown mucus. Put the brown slime in a tube furnace, heat it up to 300°C without air, keep it warm at 300°C for 3 hours, and sinter it for 3 hours; cool it down to room temperature, and crush it into a powdery precursor with a particle size of 20 mesh; put the powdery precursor on Al 2 o 3 In a porcelain boat, sinter at 400℃ for 8h in an air atmosphere, and cool naturally to room temperature to prepare carbon compounds.

[0032] 2) Preparation of reduced carbon compounds

[0033] According to Na 2 SO 3 Weighing Na with a weight ratio of 1:1 to carbon compounds 2 SO 3 ; 2 SO 3 Dissolve in distilled water 200 time...

Embodiment 2

[0037] 1) Preparation of carbon compounds

[0038] Mix citric acid and ethylene glycol according to the molar ratio of 1:4, stir at 70°C for 2h, put the pressure at 10132Pa, and stir at 175°C for 5h to carry out the polymerization reaction. Vacuum dry at a temperature of 175°C and a pressure of 1013Pa to remove ethylene glycol that has not participated in the polymerization reaction to obtain a brown mucus; heat the brown mucus to 300°C in isolation from the air, keep it at 300°C for 3 hours; cool to room temperature, and crush it into a particle size 200 mesh powdered precursor; put the powdered precursor on Al 2 o 3 In a porcelain boat, sinter at 400°C for 8h in an air atmosphere, and cool naturally to prepare carbon compounds.

[0039] 2) Preparation of reduced carbon compounds

[0040] Weigh sodium borohydride according to the weight ratio of sodium borohydride to carbon compound 1:1000; dissolve sodium borohydride in deionized water 200 times its volume to obtain sodiu...

Embodiment 3

[0044] 1) Preparation of carbon compounds

[0045] Mix citric acid and ethylene glycol according to the molar ratio of 1:4, stir at 60°C for 2h, place at 1013Pa and stir at 165°C for 5h to carry out polymerization reaction; vacuum dry at 175°C under 1013Pa pressure to remove Ethylene glycol, resulting in a brown mucus. Heat the brown viscous material to 300°C in isolation from the air, sinter at 300°C for 3 hours, cool to room temperature, and pulverize into a powdery precursor with a particle size of 100 mesh; 2 o 3 In a porcelain boat, sinter at 400°C for 8h in an air atmosphere, and cool naturally to room temperature to prepare carbon compounds.

[0046] 2) Preparation of reduced carbon compounds

[0047] Weigh triethylsilane according to the weight ratio of triethylsilane to carbon compound at 1:100. Dissolve triethylsilane in deionized water whose volume is 200 times its volume to prepare a triethylsilane solution. Add the carbon compound into the triethylsilane solu...

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Abstract

The invention relates to a method for preparing a reduction carbon nano tube coated lithium iron phosphate cathode material, which is characterized by comprising the following preparation process of: heating citric acid and ethylene glycol to perform polymerization reaction, then carrying out air isolation presintering, cooling and grinding and sintering at a temperature of 400 DEG C in the air atmosphere to obtain a carbon compound; mixing the prepared carbon compound and a mixture of reducing agents to obtain a reduction carbon compound; carrying out mixing and ball milling on the reduction carbon compound, a lithium source compound, a ferrous source compound, a phosphoric acid source compound and a wet grinding medium and carrying out vacuum drying to obtain dry powder; and placing the dry powder in the inert atmosphere or the weakly reducing atmosphere, cooling, grinding and sieving the dry powder after sintering the dry powder at a temperature of 300 DEG C, placing the obtained powder in the inert atmosphere or the weakly reducing atmosphere again and obtaining the reduction carbon nano tube coated lithium iron phosphate cathode material by adopting a two-phase sintering method. The electrode material prepared by the method disclosed by the invention has uniform composition and has excellent discharge performance, particularly excellent discharge circulating performance under the condition of large current.

Description

technical field [0001] The invention belongs to the technical field of lithium ion battery electrode materials, and relates to a preparation method of a lithium ferrous phosphate cathode material coated with reduced carbon nanotubes, which can be used in lithium ion batteries, lithium batteries, polymer lithium ion batteries and supercapacitors. technical background [0002] As a new generation of energy systems, lithium-ion batteries are widely used in electric vehicles, satellites, aerospace and military fields. Numerous studies have shown that LiFeP0 4 May become one of the most promising cathode materials for lithium-ion batteries. However, since LiFeP0 4 Due to the limitations of its own structure, the material has low electronic conductivity and poor ion conductivity, resulting in poor performance of high-rate charge and discharge, and it cannot meet the requirements of practical applications without modification. In order to overcome the shortage of lithium iron ph...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/58
CPCY02E60/10
Inventor 童庆松黄娟韩铭姜祥祥周慧蔡斌王浪
Owner 贵州唯特高新能源科技有限公司