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Graphene and nitrogen-doped carbon co-coated porous lithium titanate and preparation method thereof

A nitrogen-doped carbon, porous lithium titanate technology, applied in batteries, structural parts, electrical components, etc., can solve the problems of shortening the diffusion distance of lithium ions, large diffusion distance of lithium ions, complex composite modification process, etc. For large-scale production, uniform particle size and pore size distribution, high-capacity effects

Inactive Publication Date: 2018-02-23
SHANDONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] Due to the larger particles of commercial lithium titanate, the contact area with the electrolyte is small and the diffusion distance of lithium ions is large, while the porous material can increase the contact area between the material and the electrolyte and shorten the diffusion distance of lithium ions, which can greatly improve The rate performance of lithium titanate; however, ordinary lithium titanate has poor conductivity, so the method of surface coating carbon is often used to improve its conductivity, but this method has problems such as uneven coating layer and complex modification process

Method used

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  • Graphene and nitrogen-doped carbon co-coated porous lithium titanate and preparation method thereof
  • Graphene and nitrogen-doped carbon co-coated porous lithium titanate and preparation method thereof
  • Graphene and nitrogen-doped carbon co-coated porous lithium titanate and preparation method thereof

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Experimental program
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Effect test

Embodiment 1

[0047] 1) Add 18ml DMF and 2ml methanol to a 100ml polytetrafluoroethylene stainless steel reactor, weigh out 1% graphene oxide, 6mmol 2-aminoterephthalic acid and 1.5mmol tetra-n-butyl titanate, stir well to obtain the precursor Body solution.

[0048] 2) Seal the precursor solution in step 1), put it in an oven and heat it at 120° C. for 96 hours to obtain graphene-coated MOF-Ti.

[0049] 3) Put lithium carbonate and MOF-Ti in step 2) into a ball mill, mix and ball mill for 0.5h, where Li:Ti=4:5 (molar ratio), the ball milled product is heated at 1°C / min under argon atmosphere The rate of heating to 300 ℃ calcination 48h, that is, graphene and nitrogen-doped carbon co-coated porous lithium titanate.

Embodiment 2

[0051] 1) Add 18ml DMF and 2ml ethanol to a 100ml polytetrafluoroethylene stainless steel reactor, weigh 50% graphene oxide, 7mmol p-aminoisophthalic acid and 2mmol tetra-n-butyl titanate, stir evenly to obtain the precursor Body solution.

[0052] 2) Seal the precursor solution in step 1), put it in an oven and heat it at 200° C. for 24 hours to obtain graphene-coated MOF-Ti.

[0053] 3) Put lithium carbonate and MOF-Ti in step 2) into a ball mill and mix and ball mill for 1h, where Li:Ti=4.05:5 (molar ratio), the ball milled product is heated at 3℃ / min under argon atmosphere The rate is heated to 350°C and calcined for 48 hours to obtain graphene and nitrogen-doped carbon co-coated porous lithium titanate.

Embodiment 3

[0055] 1) Add 18 ml of DMF and 2 ml of deionized water to a 100 ml polytetrafluoroethylene stainless steel reactor, weigh 0.2 g of graphene oxide, 9 mmol of 3-aminobenzoic acid and 0.1 mmol of potassium titanium oxalate, and stir evenly to obtain a precursor solution.

[0056] 2) Seal the precursor solution in step 1), put it in an oven and heat it at 80° C. for 96 hours to obtain graphene-coated MOF-Ti.

[0057] 3) Put lithium carbonate and MOF-Ti in step 2) into a ball mill, mix and ball mill for 3 hours, where Li:Ti=4.15:5 (molar ratio), the ball milled product is heated at 20°C / min under argon atmosphere The rate is heated to 1000° C. and calcined for 1 hour to obtain graphene and nitrogen-doped carbon co-coated porous lithium titanate.

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Abstract

The invention provides a graphene and nitrogen-doped carbon co-coated porous lithium titanate and a preparation method thereof. The method comprises the following steps: 1) mixing graphene oxide, a titanium source and an organic ligand with a solvent according to a certain ratio, and performing stirring to uniformly disperse the above materials in order to obtain a precursor solution; 2) heating and reacting the precursor solution obtained in step 1) for a certain period of time in order to obtain a metal-organic framework compound of graphene-based titanium; and 3) mixing the metal-organic framework compound of graphene-based titanium, obtained in step 2, with a lithium source according to a certain ratio, performing ball milling in an inert atmosphere, and calcining the obtained ball-milled mixture to obtain the graphene and nitrogen-doped carbon co-coated porous lithium titanate. The porous lithium titanate prepared in the invention has the advantages of uniform nano-scale dispersion, uniform particle size and porosity distribution, stable structure, excellent electrochemical performances, good rate performances and high conductivity, and the preparation method has the advantages of greenness, environmental protection, short reaction time, low synthesis temperature, and easiness in industrialization.

Description

Technical field [0001] The invention belongs to the technical field of lithium ion batteries, and specifically relates to a graphene and nitrogen-doped carbon co-coated porous lithium titanate and a preparation method thereof. Background technique [0002] With the development of economy, traditional fossil energy resources are limited, polluting the environment, energy crisis and environmental pollution problems have become increasingly prominent. Therefore, the development of new types of clean energy is particularly important, such as wind energy, nuclear energy, solar energy, biomass, and geothermal energy. For the development and utilization of these new energy sources, a complete and unified theoretical system needs to be established, and energy storage is particularly important. [0003] Lithium-ion batteries have many advantages such as high energy density, high output power, long charge and discharge life, no pollution, wide operating temperature range and small self-disc...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/485H01M4/62H01M10/0525
CPCH01M4/366H01M4/485H01M4/625H01M10/0525H01M2220/20Y02E60/10
Inventor 冯金奎安永灵
Owner SHANDONG UNIV