Method for preparing asphalt mesocarbon microbeads and application in lithium battery cathode material thereof

A technology of mesophase pitch and carbon microspheres, applied in battery electrodes, circuits, electrical components, etc., can solve the problems of low yield, high yield, narrow distribution, etc., achieve low capacity decay rate, good rate performance, process simple effect

Inactive Publication Date: 2011-10-26
BEIJING UNIV OF CHEM TECH
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Problems solved by technology

The polycondensation method is to condense the polycyclic aromatic hydrocarbon raw materials into mesophase pellets through heat treatment, and then take appropriate means to lift the pellets out, but the polymerization product obtained by this method has high viscosity, difficult separation, low yield and wide spherical diameter distribution [Wang Hongqiang, Li Xinjun, Guo Huajun, etc. The influence of mesophase carbon microsphere structure on its electrochemical performance[J]. Journal of Central South University of Technology, 2003, 34(2): 140-143]
The emulsification method directly uses the mesophase pitch as the raw material to emulsify into balls through a high-temperature dispersion medium. Compared with the polycondensation method, its advantages are that the particle size of the product is controllable, the distribution is narrow, and the yield is high; the disadvantage is that the mesophase pitch raw material is not easy to be dispersed in the dispersion medium. The dispersion is uniform, and the existing emulsification method can only obtain small balls with a diameter of about 20 μm, and it is difficult to obtain products with a smaller diameter [Li Fuhu, Shen Zengmin, Xue Ruisheng, etc. Research on the preparation of mesophase carbon microspheres by emulsion method [J]. New Carbon Materials, 2004, 19(1): 21-27.]

Method used

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  • Method for preparing asphalt mesocarbon microbeads and application in lithium battery cathode material thereof
  • Method for preparing asphalt mesocarbon microbeads and application in lithium battery cathode material thereof
  • Method for preparing asphalt mesocarbon microbeads and application in lithium battery cathode material thereof

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Experimental program
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Effect test

Embodiment 1

[0016] Centrifuge the pulverized asphalt raw material particles with a particle size of 1-30 μm at a speed of 2000r / min for 5 minutes to separate the raw material particles with a particle size of 1-2 μm, take 1g of the raw material particles, and disperse them evenly in 20ml of petroleum ether Then add this asphalt petroleum ether mixture into 100ml of high temperature resistant silicone oil, keep stirring at a speed of 300r / min for 5min; while continuing to stir, stop heating when the system is rapidly heated to 270°C, and naturally cool to room temperature; use high-speed centrifugation The product pellets were centrifuged and washed with petroleum ether to obtain pure mesophase pitch microspheres with small particle size.

[0017] In a blast oven, pre-oxidize at 150°C for 6 hours, 250°C for 6 hours, then carbonize at 1000°C for 1 hour, and graphitize at 2800°C for 1 hour to obtain mesophase carbon microspheres with a particle size of 1-2 μm.

[0018] as attached figure 1 ...

Embodiment 2

[0020] The preparation method is the same as in Example 1, except that the raw material particles with a particle size of 3-30 μm (in Example 1, the raw material particles with a particle size of 1-2 μm were removed) were centrifuged at 1500r / min for 5min, and the particles with a particle size of 3 μm were separated. -5μm mesophase pitch particles, stop heating when the system rapidly heats up to 260°C,

[0021] In a blast oven, pre-oxidize at 200°C for 4 hours, 300°C for 4 hours, carbonize at 1000°C for 1 hour, and graphitize at 2800°C for 1 hour to obtain mesophase carbon microspheres with a particle size of 3-5 μm.

[0022] as attached image 3 The electrochemical performance test results show that the battery is stable at about 300mAh / g after 50 cycles; Figure 4 As shown in the charge and discharge rate performance diagram, the average discharge specific capacity of 50mA / g is 305.3mAh / g, the average discharge specific capacity of 100mA / g is 218.3mAh / g, 200mA / g, the aver...

Embodiment 3

[0024] The preparation method is the same as in Example 1, except that the pulverized asphalt raw material particles with a particle size of 1-30 μm are centrifuged at 1000 r / min for 5 minutes to separate the raw material particles with a particle size of 1-5 μm, and finally obtain a particle size of 1-5 μm Mesophase carbon microspheres.

[0025] as attached image 3 The electrochemical performance test results show that the battery is stable at about 300mAh / g after 50 cycles; Figure 4 As shown in the charge and discharge rate performance diagram, the average discharge specific capacity of 50mA / g is 379.3mAh / g, the average discharge specific capacity of 100mA / g is 341.8mAh / g, 200mA / g, the average discharge specific capacity is 248.3mAh / g, 400mA / g, The average discharge specific capacity is 122.4mAh / g. Due to the existence of 1-2μm particles, the charge-discharge specific capacity is high under high current density, the rate performance is good, and it still maintains a high ...

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Abstract

Based on the emulsification method and the suspension method, mesocarbon microbeads, which are successfully prepared by improving technologies with the particle size being 1-5 microns, have good dispersibility. When the asphalt mesocarbon microbeads are used as the lithium battery cathode material, battery storage capacity and rate capacity have prominent performance: with the increase of charge-discharge current, the capacity fading rate is low and the rate capacity is good at 50 mA / G-400mA / g with the specific discharge capacity being 271 mAh / g-114.7 mAh / g.

Description

technical field [0001] The invention relates to the field of lithium ion battery negative electrode materials, in particular to a preparation method of mesophase carbon microspheres. Background technique [0002] Mesophase pitch carbon microspheres (MCMB) is a new type of carbon material, which also shows excellent performance in lithium-ion secondary battery anode materials [Song Huaihe, Chen Xiaohong, Zhang Songyun, Gao Yan. Mesophase pitch carbon microspheres and Its application in lithium-ion secondary batteries [J]. Carbon Materials, 2002 (1): 28]. The electrochemical intercalation and deintercalation process of lithium ions is controlled by charge transport and mass transport, so when using mesophase pitch carbon microspheres (MCMB) as the negative electrode material of lithium batteries, the smaller the particle size of MCMB, the better the accumulation between particles will be. Tight, the lithium ion diffusion path is short. This not only improves the cycle perfor...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B31/02H01M4/1393H01M4/133
CPCY02E60/10
Inventor 宋怀河徐斌陈晓红
Owner BEIJING UNIV OF CHEM TECH
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