Preparation method of compound graphite material for lithium ion secondary battery

A lithium-ion battery and composite graphite technology, which is applied in the direction of graphite, battery electrodes, chemical instruments and methods, etc., can solve the problems of large electrode expansion, battery magnification, and low temperature performance that cannot meet higher and higher requirements, lithium ion detachment, intercalation, etc. Path length and other issues

Active Publication Date: 2013-08-14
DONGGUAN KAIJIN NEW ENERGY TECH
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  • Abstract
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  • Application Information

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Problems solved by technology

[0006] In the materials prepared by the above-mentioned patents, the graphite particles are easy to form orientation, especially after compaction, the flat graphite particles are oriented on the pole piece, the lith

Method used

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  • Preparation method of compound graphite material for lithium ion secondary battery
  • Preparation method of compound graphite material for lithium ion secondary battery
  • Preparation method of compound graphite material for lithium ion secondary battery

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preparation example Construction

[0028] The preparation method of the present invention comprises the following steps:

[0029] (1) Mixing of raw materials: put natural graphite, binder, and graphite catalyst as raw materials into the drum furnace, and the drum keeps rotating during the feeding process of raw materials; the mass percentage content of each component in the raw materials is:

[0030] Natural graphite: 70% to 90%;

[0031] Binder: 5% to 30%;

[0032] Graphite catalyst: 1% to 5%;

[0033] The binder is a material capable of forming artificial graphite after graphitization; the natural graphite is coated by stirring the binder, and the bonding of the natural graphite is realized.

[0034] (2) Progressive heating: The heating of the raw materials in the furnace adopts a gradual heating and heating method. During the heating process, the drum furnace keeps rotating, and the drum speed is adjusted to 10-100Hz. It includes the following heating stages:

[0035] The first stage, from room temperatu...

Embodiment 1

[0050] Throw 222.5kg of natural graphite (D5015um), 25kg of coal tar pitch (D5010um) and 2.5kg of graphitization catalyst SiC into the drum furnace, feed while the drum is rotating, and heat and knead after feeding. Adjust the rotating speed of the drum to 30Hz, and the heating program is as follows: normal temperature to 200°C for 1 hour, 200°C to 400°C for 3 hours, 400°C to 600°C for 3 hours, 600°C for 2 hours. Let cool to room temperature. Then catalyzed graphitization treatment at 3000°C and chlorine gas. The resulting graphitized material was sieved, and large particles were removed with a 250-mesh screen to obtain composite graphite particles (D5021.0um), with a capacity of 362mAh / g and an efficiency of 92.1%.

[0051] The composite graphite particle index that present embodiment makes is as follows table 1:

[0052]

[0053] See figure 1 As shown, the composite graphite material finally obtained after treatment has natural graphite in its center, and the outer lay...

Embodiment 2

[0056] Throw 210kg of natural graphite (D5013um), 37.5kg of coal tar pitch (D5012um) and 22.5kg of graphitization catalyst SiO into the drum furnace, feed while the drum is rotating, and heat and knead after feeding. Adjust the rotating speed of the drum to 30Hz, and the heating program is as follows: room temperature to 200°C for 2 hours, 200°C to 400°C for 5 hours, 400°C to 600°C for 5 hours, 600°C for 3 hours. Let cool to room temperature. Then catalyzed graphitization treatment at 3000°C and chlorine gas. The resulting graphitized material was sieved, and large particles were removed with a 250-mesh screen to obtain composite graphite particles (D5020um), with a capacity of 363mAh / g and an efficiency of 92.4%.

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Abstract

The invention discloses a preparation method of a compound graphite material for a lithium ion secondary battery. The preparation method comprises the following steps of: firstly pouring natural graphite, a binding agent and a graphite catalyst which are taken as raw materials into a roller furnace, wherein the roller furnace rotates all the time in a raw material pouring process; then progressively heating the raw materials, namely heating the raw materials in the roller furnace by adopting a progressive heating mode while the roller furnace rotates in a heating process, and then carrying out natural cooling to normal temperature after the raw materials in the roller furnace are heated; and finally carrying out graphitizing treatment on the raw materials, thus the binding agent forms artificial graphite, and the artificial graphite forms a coating on natural graphite particles, so as to form a shell-core structure, and compound particles of the shell-core structure are further spliced to form compound graphite particles with the required grain diameter. The compound graphite material prepared by the invention is of the shell-core structure with the natural graphite as an inner core and an artificial graphite layer as a coating, and the compound graphite has good isotropy, high capacity, high compactness, excellent multiplying, low temperature and cyclic performances and low electrode expansion. The preparation method of the compound graphite material for the lithium ion secondary battery adopts a method that coating and splicing are carried out at the same time, the preparation method is simple and practicable, and the cost is low.

Description

technical field [0001] The invention relates to the field of preparation methods of negative electrode materials for lithium-ion batteries, in particular to a preparation method for a composite graphite material for secondary lithium-ion batteries. The graphite material prepared by the method forms a core-shell structure, and the core-shell structure graphite particles are bonded The isotropic composite graphite particle material formed directly. Background technique [0002] Due to the development of advanced electronic equipment, there is an increasing demand for small, lightweight, and portable electronic equipment and devices. Longer operating times are required after charging, and therefore, batteries with high energy density are required to power such devices and devices. [0003] Lithium-ion battery anode materials, as an important part of lithium-ion batteries, contribute greatly to battery capacity. The anode materials that have been studied so far include: graphit...

Claims

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Application Information

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IPC IPC(8): C01B31/04H01M4/587H01M4/1393C01B32/205C01B32/21
CPCY02E60/122Y02E60/10
Inventor 仰永军
Owner DONGGUAN KAIJIN NEW ENERGY TECH
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