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Composite carbon negative electrode material of lithium ion power battery and its preparation method

A power battery and negative electrode material technology, applied in the direction of battery electrodes, circuits, electrical components, etc., can solve the problems of increasing battery internal resistance, small reaction area, electrode structure damage, etc., and achieves low cost, simple preparation process, and easy operation Effect

Active Publication Date: 2006-12-27
BTR NEW MATERIAL GRP CO LTD
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] However, due to the high degree of graphitization and highly oriented graphite layer structure, graphite materials have poor compatibility with organic solvents, and co-intercalation of lithium and organic solvents, graphite interlayer exfoliation, graphite Particles crack and pulverize, resulting in damage to the electrode structure and reduced charge-discharge cycles; in addition, because the graphite flake structure only allows lithium ions to be inserted and extracted along the boundaries of graphite crystals, the reaction area is small and the diffusion path is long, so it is generally not suitable for large currents. Discharge
In addition, the graphite negative electrode material is easy to form flake particles with a large aspect ratio during the pulverization process of powder preparation, and the flake particles form an orientation parallel to the current collector during the rolling process of electrode preparation. During the discharge process, when lithium ions enter and exit the interior of the graphite crystal, a large strain will be generated in the c-axis direction of the graphite, resulting in the destruction of the electrode structure and affecting the cycle performance, and the result of the oriented arrangement of the flake graphite particles will also cause lithium ions to flow from the graphite crystal. The resistance of the side entry and exit increases, and the rapid charge and discharge performance deteriorates
And, because graphite crystals of flake particles have a larger specific surface area compared with spherical and massive graphite particles, the anode material of a lithium-ion battery has a larger irreversible capacity in the first charge and discharge process, and graphite powder and The combination of the current collector is poor, and a large amount of binder needs to be added, which increases the internal resistance of the battery, reduces the discharge capacity, and deteriorates the rapid charge and discharge performance and cycle performance

Method used

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  • Composite carbon negative electrode material of lithium ion power battery and its preparation method
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  • Composite carbon negative electrode material of lithium ion power battery and its preparation method

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preparation example Construction

[0023] The preparation method of the lithium-ion power battery composite carbon negative electrode material of the present invention comprises the following steps: 1. Graphite powder with a particle size of 0.1 μm to 40 μm and a fixed carbon content ≥ 94%, additives accounting for 0.1 to 5% of the weight of the graphite powder, The binder accounting for 1 to 50% of the weight of the graphite powder is mixed and granulated. First, add the graphite powder, then add additives, and then add the binder after mixing; 2. Extrude the mixed pellets, and the density after molding is 1.6~1.75g / cm 3 , followed by roasting and impregnation, using the conventional graphite electrode roasting and impregnation process, roasting in a staged heating method, the roasting temperature is 130°C-1300°C, the heating rate is 1.3-10°C / h, and the roasting time is 320h-420h; Add hot asphalt at 160°C to 180°C, immerse the product, pressurize at 1.18 to 2.5MPa, and keep it for 2 to 4 hours. When the densit...

Embodiment 1

[0041] Example 1, with 100 parts by weight of spherical natural graphite powder with an average particle size of 8 μm and a carbon content of 95%, add 2 parts by weight of conductive carbon black as an additive, 10 parts by weight of an organic binder thermosetting phenolic resin, and mix an appropriate amount of solvent absolute ethanol Evenly, evaporate the solvent to dryness. Density after pressing: 1.65g / cm 3 , the mixture was graphitized at a temperature of 2800° C. for 4 hours, then cooled to room temperature, and pulverized by a high-pressure pulverizer to obtain composite carbon particles with an average particle size of 20 μm. Such as figure 2 As shown in the scanning electron microscope photos, it can be seen that the composite carbon particles are composed of spherical graphite and carbon materials coated on the surface. The long The diameter ratio is 1.6, and the d of graphite crystal is obtained by powder X-ray wide-angle diffraction method. 002 It is 0.3358nm...

Embodiment 2

[0043]Example 2, 50 parts by weight of natural graphite powder with an average particle size of 10 μm and a carbon content of 99.9% is mixed evenly with 50 parts by weight of artificial graphite powder of the same particle size and carbon content, and 10 parts by weight of binder pitch is added, and the additive VGCF 1.5 Parts by weight were mixed and coated at a temperature of 150°C, and the mixture was carbonized at a temperature of 1000°C for 4 hours, then lowered to room temperature, and pulverized by a low-speed impact ball mill to obtain composite carbon particles with an average particle size of 20 μm. From the scanning electron microscope photos of the composite carbon particles, it can be seen that the composite carbon particles are composed of spherical graphite and the carbon material coating on the surface, and the aspect ratio of the composite carbon material is 3.6 through image analyzer analysis and testing. The d of graphite crystals obtained by powder X-ray wid...

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Abstract

The disclosed composite carbon cathode material for Li ion electro-kinetic cell is prepared by bonding composite spherical or near-spherical graphite particle, wherein the material composes by: graphous or natural graphite powder or their mixture, 0.1-5wt% additive, and 1-50wt% bonding agent. The preparation method comprises: granulating, baking, dipping, impregnating, carbonizating, and graphitizing. Compared with prior art, this invention has reversible specific capacity more than 350mAh / g, first circulation coulomb efficiency more than 94%, capacity conservation rate more than 80% after 500 times of circulation, and other well performances.

Description

technical field [0001] The invention relates to a battery negative electrode material and a preparation method thereof, in particular to a composite graphite negative electrode material of a lithium ion power battery and a preparation method thereof. Background technique [0002] Since Japan's Sony Corporation took the lead in developing and commercializing lithium-ion batteries in 1990, lithium-ion batteries have developed rapidly. Today lithium-ion batteries have been widely used in various fields of civil and military use. With the continuous advancement of science and technology, people have put forward more and higher requirements for the performance of batteries: the miniaturization and personalized development of electronic equipment requires batteries to have smaller volumes and higher specific energy output; aerospace energy requirements Batteries have cycle life, better low-temperature charge and discharge performance, and higher safety performance; electric vehic...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/58C01B31/02H01M4/583H01M4/62
CPCY02E60/12Y02E60/10
Inventor 岳敏张万红
Owner BTR NEW MATERIAL GRP CO LTD
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