High-rate natural graphite-based composite material for lithium ion battery as well as preparation method and application of high-rate natural graphite-based composite material

A natural graphite and composite material technology, applied in battery electrodes, electrode manufacturing, electrode rolling/calendering, etc., can solve the problems of poor affinity between resin carbon and graphite, low initial charge and discharge efficiency, and large specific surface area of ​​hard carbon. Achieve the effect of improving charge and discharge efficiency, improving cycle performance and rate performance, and stable product properties

Active Publication Date: 2021-07-13
GUANGDONG OCEAN UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the affinity between resin carbon and graphite is poor, organic solvents are used in the preparation process, the process is complicated, and the hard carbon coating is easy to fall off during the charge and discharge process. In addition, the specific surface area of ​​hard carbon is large, and the first charge and discharge of the material low efficiency

Method used

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  • High-rate natural graphite-based composite material for lithium ion battery as well as preparation method and application of high-rate natural graphite-based composite material
  • High-rate natural graphite-based composite material for lithium ion battery as well as preparation method and application of high-rate natural graphite-based composite material

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[0030] The preparation method of the present invention will be further described in detail in conjunction with specific examples below. It should be understood that the following examples are only for illustrating and explaining the present invention, and should not be construed as limiting the protection scope of the present invention. All technologies realized based on the above contents of the present invention are covered within the scope of protection intended by the present invention.

[0031] The experimental methods used in the following examples are conventional methods unless otherwise specified; the reagents and materials used in the following examples can be obtained from commercial sources unless otherwise specified.

Embodiment 1

[0033] Spherical graphite (D 50 17μm, d 002 0.3386nm) and asphalt (softening point is 200°C, D 50 3μm) into the mixer according to the mass ratio of 100:6, adjust the speed to 240r / min, and mix for 1.5 hours to obtain the mixture; put the mixture into the kneading pot, knead at 320°C under the air atmosphere, and wait in the kneading pot After the material is soft, it is cooled to obtain a kneaded material; the kneaded material is pressurized to 100 MPa, and kept at room temperature for 10 minutes to obtain a graphite block. Break up the graphite blocks in an air-flow type disperser, and then put the dispersant into a tube furnace in a nitrogen atmosphere at a rate of 20 °C / min to rapidly heat up to 300 °C, and then use a heating rate of 2 °C / min The heating rate is slowly raised to 700°C, and finally the temperature is rapidly raised to 1200°C at a heating rate of 25°C / min, and kept for 2 hours. After cooling, it is dispersed, sieved, and demagnetized to obtain a natural gr...

Embodiment 2

[0035] Spherical graphite (D 50 13μm, d 002 0.3390nm) and asphalt (softening point is 220°C, D 50 2μm) into the mixer according to the mass ratio of 100:8, adjust the speed to 200r / min, and mix for 2.0 hours to obtain the mixture; put the mixture into the kneading pot, knead at 300°C under the air atmosphere, and wait in the kneading pot After the material is soft, it is cooled to obtain a kneaded material; the kneaded material is pressurized to 80 MPa, and the pressure is maintained at room temperature for 25 minutes to obtain a graphite block. Break up the graphite blocks in an air-flow disperser, and then put the dispersant into a tube furnace in a nitrogen atmosphere at a rate of 25 °C / min to rapidly heat up to 300 °C, and then use a heating rate of 3 °C / min. The heating rate is slowly raised to 700°C, and finally the temperature is rapidly raised to 1100°C at a heating rate of 20°C / min, and kept for 2 hours. After cooling, it is dispersed, sieved, and demagnetized to ob...

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Abstract

The invention provides a high-rate natural graphite-based composite material for a lithium ion battery as well as a preparation method and application of the high-rate natural graphite-based composite material. According to the invention, asphalt with good compatibility with graphite is adopted to replace resin carbon, and an oxygen functional group is introduced into the asphalt in a low-temperature pre-oxidation process, so that mutual crosslinking of an asphalt structure is induced; and then the pre-oxidized asphalt is pressed into the defects on the inner surface and the outer surface of the micro-expansion layer spherical graphite by adopting an isostatic pressing technology, and coating is performed synchronously, so that the pre-oxidized asphalt is not easy to form an ordered structure in a high-temperature carbonization process and is converted into hard carbon, wherein the obtained composite material comprises micro-expansion layer spherical graphite and hard carbon coating the inner surface and the outer surface of the micro-expansion layer spherical graphite. Through the coating, synchronous modification and integration of defect sites on the inner surface and the outer surface of the micro-expansion layer spherical graphite can be realized, so that the cycle performance and the rate capability of the natural graphite are improved.

Description

technical field [0001] The invention belongs to the technical field of carbon negative electrode materials for lithium-ion batteries, and in particular relates to a high-rate natural graphite-based composite material for lithium-ion batteries and its preparation method and application. Background technique [0002] Lithium-ion batteries have become a new generation of secondary batteries since the 1990s after nickel-metal hydride batteries because of their advantages such as high operating voltage, high energy density, long cycle life, small self-discharge, and no memory effect. In recent years, with the continuous improvement of the miniaturization, light weight, multi-function and long-time driving requirements of electronic products, vehicle-mounted and energy storage equipment, the requirements for high energy density and high rate performance of lithium-ion batteries have been continuously improved. At present, the anode materials of commercial lithium-ion batteries are...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/1393H01M4/04H01M4/133H01M4/36H01M4/583H01M4/62
CPCH01M4/1393H01M4/0435H01M4/364H01M4/0471H01M4/133H01M4/583H01M4/62H01M2004/027H01M2004/021Y02E60/10
Inventor 赵娟
Owner GUANGDONG OCEAN UNIVERSITY
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