Composite conductive agent and preparation method thereof, and lithium ion battery

A technology of composite conductive agent and conductive agent, which is applied in the direction of battery electrodes, secondary batteries, circuits, etc., can solve the problems of carbon nanotube agglomerates being unable to disperse, low yield, and affecting the conductivity of carbon nanotubes, so as to improve electron transmission Efficiency, the effect of solving the difficulty of dispersion and reducing the probability of insufficient contact

Active Publication Date: 2020-12-04
HEFEI GUOXUAN HIGH TECH POWER ENERGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The methods of physically dispersing carbon nanotubes mainly include ultrasonic dispersion, shear mixing, grinding, etc., which have the advantages of large processing capacity and no damage to the surface of carbon nanotubes. However, single physical dispersion can only make carbon nanotube aggregates macroscopically and The matrix powder is mixed, unable to disperse the carbon nanotube aggregates themselves
Chemical dispersion is mainly to modify hydrophilic functional groups such as hydroxyl, carboxyl or polymers with hydrophilic ends on its surface to improve its dispersibility. The method of chemically dispersing carbon nanotubes has low yield, and excessive modification may affect the electrical conductivity of carbon nanotubes.

Method used

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  • Composite conductive agent and preparation method thereof, and lithium ion battery
  • Composite conductive agent and preparation method thereof, and lithium ion battery
  • Composite conductive agent and preparation method thereof, and lithium ion battery

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032] Step 1: Weigh 5g SWCNTs and 150g MWCNTs, add them to the reactor containing concentrated nitric acid solution, heat and stir at 50°C for 3h, cool, wash to pH ≈ 7, and dry to obtain acidified carbon nanotubes;

[0033] Step 2: The obtained acidified carbon nanotubes were ball milled with 1.2Kg SP for 24h, fully mixed, and then ultrasonically and stirred to disperse in 67.75Kg of Zn(NO) with a mass concentration of 0.5wt.%. 3 ) 2 In anhydrous methanol, use ammonia water to adjust PH ≈ 9, leave it to age for 12 hours, and obtain a mixed solution;

[0034] Step 3: Slowly add 800 g of 2-methylimidazole into the mixed solution in Step 2 under stirring condition, and stir for 6 hours to obtain a precipitate, which is centrifuged, washed, and dried at 80°C to obtain a solid powder;

[0035] Step 4: Place the solid powder obtained in Step 3 into pure N 2 Pyrolyze at 800°C for 2 hours in a gas environment, and the heating rate is 5°C / min to obtain a black powder, then pickle th...

Embodiment 2

[0040] Step 1: Weigh 5g of SWCNTs and 300g of MWCNTs, add them to a reactor containing concentrated nitric acid solution, heat and stir at 50°C for 3 hours, cool, wash to pH ≈ 7, and dry to obtain acidified carbon nanotubes;

[0041] Step 2: The obtained acidified carbon nanotubes were ball milled with 2.44Kg SP for 24h, fully mixed, and then ultrasonically and stirred to disperse in 122Kg of Zn(NO 3 ) 2 In anhydrous methanol, use ammonia water to adjust PH ≈ 9, leave it to age for 24 hours, and obtain a mixed solution;

[0042] Step 3: Slowly add 1.22Kg of 2-methylimidazole into the mixture in Step 2 under stirring condition, and stir for 6 hours to obtain a precipitate, which is centrifuged, washed, and dried at 80°C to obtain a solid powder;

[0043] Step 4: Place the solid powder obtained in Step 3 into pure N 2 Pyrolyze at 900°C for 1 hour in a gas environment with a heating rate of 5°C / min to obtain a black powder, then pickle the black powder in a dilute hydrochloric ...

Embodiment 3

[0048] Step 1: Weigh 5g of SWCNTs and 250g of MWCNTs, add them to a reactor containing concentrated nitric acid solution, heat and stir at 50°C for 3 hours, cool, wash to pH ≈ 7, and dry to obtain acidified carbon nanotubes;

[0049] Step 2: The obtained acidified carbon nanotubes were ball milled with 1.54Kg SP for 24h, fully mixed, and then ultrasonically and stirred to disperse in 67.75Kg of Zn(NO 3 ) 2 In anhydrous methanol, use ammonia water to adjust PH ≈ 9, leave it to age for 12 hours, and obtain a mixed solution;

[0050] Step 3: Slowly add 945g of 2-methylimidazole into the mixed solution of Step 2 under stirring condition, stir and react for 6h to obtain a precipitate, which is centrifuged, washed, and dried at 80°C to obtain a solid powder;

[0051] Step 4: Place the solid powder obtained in Step 3 into pure N 2 Pyrolyze at 600°C for 2 hours in a gas environment, and the heating rate is 5°C / min to obtain a black powder, then pickle the black powder in a dilute hy...

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Abstract

The invention discloses a composite conductive agent and a preparation method thereof, and a lithium ion battery, belonging to the technical field of lithium ion batteries. The composite conductive agent is prepared by growing a metal organic framework 2-methylimidazole zinc salt on the surface of an initial conductive agent, and then carrying out high-temperature carbonization and acid etching toobtain the composite conductive agent surface-coated with porous amorphous carbon, wherein the initial conductive agent is composed of a granular conductive agent and a linear conductive agent. According to the invention, the granular conductive agent is anchored on the linear conductive agent, namely a carbon nanotube, and the dispersing capacity of the carbon nanotube is improved through sterichindrance repulsion; in positive electrode slurry and negative electrode slurry, the granular conductive agent fills in gaps among active material particles, and the linear conductive agent is used for remote overlapping with the granular conductive agent to form a dot-line three-dimensional net-shaped conductive network, so the contact performance of the conductive agents and an active materialis improved, electron transmission efficiency is improved, and the probability of insufficient contact caused by expansion of active substances in the charging and discharging processes is reduced.

Description

technical field [0001] The invention relates to the technical field of lithium ion batteries, in particular to a composite conductive agent, a preparation method thereof and a lithium ion battery. Background technique [0002] With the increasingly serious crisis of energy and environment, the use and storage of clean and sustainable energy has become a research hotspot. Lithium-ion batteries have many advantages such as high energy density, flexible size, high cycle stability, and unlimited application fields, and have attracted great attention from various industries. At present, high-nickel transition metal oxides are commonly used positive electrode active materials for high specific energy lithium-ion batteries. Since most of them are semiconductors or insulators, their conductivity is between 10 -3 ~10 -9 S / cm, and the solid-phase diffusion rate of lithium ions is slow, which seriously affects its internal resistance, rate, capacity development, cycle stability and o...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/62H01M10/0525B82Y30/00B82Y40/00
CPCH01M4/625H01M10/0525B82Y30/00B82Y40/00Y02E60/10
Inventor 项胜曹勇王义飞董骄马仁良鲁冰冰
Owner HEFEI GUOXUAN HIGH TECH POWER ENERGY
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