Porous conductive additive and preparation method thereof, lithium ion battery

A porous conductive and additive technology, applied in battery electrodes, secondary batteries, circuits, etc., can solve the problems of reducing power density and energy density, heavy lithium-ion batteries, and high cost of conductive additives, achieving reduced paths, high conductivity Efficiency, effect of high electron conductivity

Active Publication Date: 2013-04-17
SHENZHEN GRADUATE SCHOOL TSINGHUA UNIV
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Problems solved by technology

Since the positive electrode material of lithium-ion batteries is basically an inorganic semiconductor, the electronic conductivity is relatively low. In order to meet the requirements of lithium-ion batteries, materials with good conductivity are often added to the positive electrode as conductive additives during the battery preparation process. According to the current conductive additives The morphology characteristics can be divided into spherical conductive carbon black, linear carbon nanofibers, carbon nanotubes, sheet-shaped conductive graphite, nano-sheet graphite and other materials. The addition of these materials can effectively improve the electronic conductivity of the positive electrode sheet. However, since the above carbon-based conductive additives are electrochemically inert materials in the positive electrode, that is, they will not provide capacity when the lithium-ion battery is working, so adding too much conductive additive will cause the lithium-ion battery to weigh too much and reduce its power. Density and Energy Density
And because the cost of some conductive additives is too high, when the amount added is too large, it will also lead to an increase in battery manufacturing costs

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  • Porous conductive additive and preparation method thereof, lithium ion battery
  • Porous conductive additive and preparation method thereof, lithium ion battery

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preparation example Construction

[0031] The present invention also provides a method for preparing the above-mentioned porous conductive additive, in one embodiment, comprising the following steps:

[0032] (1) Disperse the graphene-based material in a solvent (preferably water) to obtain a dispersed solution of the graphene-based material, then add a pore-forming agent, the mass ratio of the pore-forming agent to the graphene-based material is 0.1-1000, ultrasonic or Obtain a uniform mixed solution after stirring;

[0033] (2) Heating the mixed solution obtained in step (1) for a period of time, the heating temperature is 40-100 ° C, and the time is 0.5-100 h, so that the pore-forming agent and the graphene-based material are fully mixed, and then the solvent (such as Evaporate to remove the solvent), dry the obtained solid (the mixture of graphene-based material and pore-forming agent), and heat it under an oxygen-free protective atmosphere (such as nitrogen or argon) for 0.5-20 h at a heating temperature o...

Embodiment 1

[0042] A conductive additive, which is a graphene oxide-based particle, the shape of the particle is flake, the size in the plane direction is 1-3μm, and the specific surface area is 1300m 2 / g, the size in the thickness direction is 0.5-5nm, the diameter of the through hole is 1-800nm, the porosity of the through hole is 25%, and the effective resistivity is 4.6 mΩ.cm. Its preparation method is as follows:

[0043] First 20g graphene oxide material is dispersed in water, obtains the dispersion solution of graphene oxide material; Add 20g Fe(NO 3 ) 3 , after the ultrasonic dispersion is uniform, add ammonia water to adjust the pH of the solution to 8, then add 50 g of citric acid, heat the above solution at 80 ° C for 40 h, and then evaporate to remove water, the obtained solid (pore-forming agent and reduced oxidation Graphene material mixture) was dried and heated under an argon atmosphere for 3 h at a heating temperature of 800 °C to obtain a conductive additive with ...

Embodiment 2

[0046] A conductive additive, which is a functionalized graphene-based particle modified with N-doping, the shape of the particle is flake-shaped, the size in the plane direction is 0.8-3 μm, and the specific surface area is 900m 2 / g, the size in the thickness direction is 0.2-3nm, the diameter of the through hole is 5-780nm, the porosity of the through hole is 35%, and the effective resistivity is 4.3 mΩ.cm. Its preparation method is as follows:

[0047] First, 1.8g of the functionalized graphene material modified with N doping is dispersed in water to obtain a dispersion solution of the functionalized graphene material modified with N doping; add 180g FeCl 3 , after mixing uniformly by ultrasonication for 1h, adding ammonia water to adjust the pH of the solution to 9, then adding 18g of vitamin C, heating the above solution at 85°C for 25h, and then evaporating to remove water, the obtained solid (pore-forming agent and reduction treatment) Graphene material mixture)...

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Abstract

The invention discloses a porous conductive additive and a preparation method thereof. The porous conductive additive consists of graphene-based particles, having flaky particle shapes, the size distribution of 0.01-5 microns in a planar direction, the size distribution of 0.1-50 nanometers in a thickness direction, and through holes with the diameters of 1-1000 nanometers inside, with the porosity of 20-70%. The preparation method comprises the following steps of: dispersing a graphene-based material into a solvent to obtain a dispersion solution, adding a pore forming agent in a mass ratio of the pore forming agent to the graphene-based material of 0.1-1000, and performing ultrasonic treatment or mixing to obtain a uniform mixed solution; heating the mixed solution, removing the solvent, drying an obtained solid, and heating the solid in an oxygen-free protective atmosphere to obtain the porous conductive additive. The porous conductive additive has very high conductivity efficiency and can optimize a pore structure in an electrode and reduce ion conducting paths.

Description

technical field [0001] The invention relates to a secondary battery material and a preparation method thereof, in particular to a porous conductive additive, a preparation method thereof, and a lithium ion battery. Background technique [0002] With the use of secondary batteries, such as lithium-ion batteries, in the fields of electric tools and new energy vehicles, people have put forward higher and higher requirements for the power performance of lithium-ion batteries. Since the positive electrode material of lithium-ion batteries is basically an inorganic semiconductor, the electronic conductivity is relatively low. In order to meet the requirements of lithium-ion batteries, materials with good conductivity are often added to the positive electrode as conductive additives during the battery preparation process. According to the current conductive additives The morphology characteristics can be divided into spherical conductive carbon black, linear carbon nanofibers, car...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/62H01M10/0525
CPCY02E60/10
Inventor 杨全红苏方远吕伟吕小慧李宝华康飞宇
Owner SHENZHEN GRADUATE SCHOOL TSINGHUA UNIV
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