Fluorinated graphene modified lithium titanate material and preparation and application

A technology of fluorinated graphene and lithium titanate, which is applied in the field of lithium-ion batteries and lithium-ion supercapacitors, can solve the problems of poor electronic conductivity of lithium titanate, restrictions on large-scale commercial application of lithium titanate, and battery flatulence, etc., to achieve Effects of improving rate performance, eliminating surface defects of lithium titanate, and reducing electron conduction resistance

Active Publication Date: 2020-06-05
DALIAN INST OF CHEM PHYSICS CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] Although lithium titanate has great technical advantages, the main reason that restricts the further large-scale commercial application of lithium titanate is that during the recharge and discharge process, lithium titanate catalyzes the decomposition of the electrolyte, resulting in battery flatulence.
In addition, when applied to lithium-ion supercapacitors, the poor electronic conductivity of lithium titanate is also one of the factors restricting the application, and it needs to be mixed with a large number of conductive materials.

Method used

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  • Fluorinated graphene modified lithium titanate material and preparation and application

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] After mixing lithium acetate 10g, ethanol 45g, acetic acid 2g, fluorinated graphene (F / C ratio is 1.1, 5 layers) 2g, and water 0.5g until uniform, slowly add 50g tetrabutyl titanate, after stirring for 5 hours, The liquid was evaporated to dryness to obtain an intermediate phase. Then calcined at 600°C for 8 hours under argon atmosphere, and made into powder material after cooling.

[0025] The above materials were subjected to elemental analysis, wherein the mass fraction of carbon element accounted for 10%, the mass fraction of fluorine element accounted for 5%, and the rest was lithium titanate.

[0026] The above materials were tested by XPS and peaks were divided. Among them, 684.8e V belonged to Ti-F bond, 686.6e V belonged to C-F bond, and 685.7e V belonged to C-F-Ti bond. Contains C-F-Ti bonds, Ti-F bonds, and C-F bonds. These bonds are conducive to the compound lithium titanate and fluorinated graphene on the atomic scale to greatly reduce the electron conduct...

Embodiment 2

[0037] After mixing 10 g of lithium acetate, 60 g of methanol, 3 g of acetic acid, 3 g of fluorinated graphene (F / C ratio of 1.2, 4 layers), and 0.3 g of water until uniform, slowly add 100 g of tetrapropyl titanate and stir for 4.5 hours, The liquid was evaporated to dryness to obtain an intermediate phase. Then calcined at 800°C for 68 hours under nitrogen atmosphere, and made into powder material after cooling.

[0038] The above materials are used for electrode preparation and battery testing. The conditions for electrode preparation and battery testing are shown in the table.

Embodiment 3

[0040] Lithium acetate 10g, isopropanol 80g, acetic acid 2.7g, fluorinated graphene (F / C ratio is 1.1, 5 layers) 3g, after water 0.3g are mixed uniformly, slowly add 12g tetrabutyl titanate, stir 3 After 1 hour, the liquid was evaporated to dryness to obtain an intermediate phase. Then it was calcined at 500°C for 10 hours under an argon atmosphere, and it was cooled to make a powder material.

[0041] The above materials are used for electrode preparation and battery testing. The conditions for electrode preparation and battery testing are shown in the table.

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Abstract

The invention provides a fluorinated graphene modified lithium titanate material and a preparation method thereof. The fluorinated graphene modified lithium titanate material is formed by compoundingfluorinated graphene and lithium titanate, the lithium titanate accounts for 55%-98% of the mass fraction of the whole material, preferably 62%-97%, and the best 70%-94%. The surface of the material contains a C-F-Ti bond and an F-Ti bond; the lithium titanate accounts for 55%-98% of the mass fraction of the overall material, the carbon element accounts for 1%-25% of the mass fraction of the overall material, and the fluorine element accounts for 0.2%-20% of the mass fraction of the overall material; preferably, the lithium titanate accounts for 62%-97% of the mass fraction of the overall material, the carbon element accounts for 2%-20% of the mass fraction of the overall material, and the fluorine element accounts for 0.5%-18% of the mass fraction of the overall material; for the best, the lithium titanate accounts for 70%-94% of the mass fraction of the whole material, the carbon element accounts for 5%-18% of the mass fraction of the whole material, and the fluorine element accountsfor 0.8%-15% of the mass fraction of the whole material.

Description

technical field [0001] The invention relates to the fields of lithium ion batteries and lithium ion supercapacitors, in particular to a modified lithium titanate negative electrode and a preparation method thereof. Background technique [0002] As a zero-strain material, lithium titanate hardly changes in volume during charging and discharging, which can avoid capacity attenuation caused by volume change and has a long cycle life. Therefore, lithium titanate is used as a lithium-ion power battery, lithium-ion Anode materials for supercapacitors have great research value and commercial application prospects. [0003] Although lithium titanate has great technical advantages, the main reason that restricts the further large-scale commercial application of lithium titanate is that during the recharge and discharge process, lithium titanate catalyzes the decomposition of the electrolyte, resulting in battery flatulence. In addition, when applied to lithium-ion supercapacitors, t...

Claims

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Application Information

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IPC IPC(8): H01M4/36H01M4/485H01M4/62H01M10/0525
CPCH01M4/362H01M4/485H01M4/625H01M4/628H01M10/0525Y02E60/10
Inventor 曲超张洪章李先锋张华民刘翠连
Owner DALIAN INST OF CHEM PHYSICS CHINESE ACAD OF SCI
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