Preparation method of SiOx/C surface-coated graphite cathode material

A technology of graphite anode and surface coating, which is applied in the field of preparation of SiOx/C surface-coated graphite anode materials, can solve the problems of unfavorable uniformity materials, difficult large-scale application, and high equipment requirements, and achieves improved cycle stability and ease of use. The effect of mass production and low cost

Active Publication Date: 2017-03-22
ZHONGTIAN ENERGY STORAGE TECH
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Problems solved by technology

However, the material prepared by this method is only coated with a single carbon layer, and the uniformity of the coating is difficult to ensure, and it is easy to cause powdering and breaking of the electrode material during the cycle of the electrode material.
[0004] Patent No. CN105655564A introduces SiOx / C composite negative electrode material and its preparation method and application. The preparation method uses organic gas as the carbon source. Although the coating effect is good, it requires high equipment and is difficult to apply on a large scale. Asphalt and polymer materials are prone to agglomeration and adhesion, which can easily cause large particles, which is not conducive to obtaining materials with better uniformity

Method used

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  • Preparation method of SiOx/C surface-coated graphite cathode material

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preparation example Construction

[0017] A preparation method of SiOx / C surface-coated graphite negative electrode material, the specific steps are as follows:

[0018] (1) Add SiOx, asphalt, organic acid, and dispersant to the ball mill tank to prepare a uniformly mixed slurry, and then prepare SiOx / C materials by spray granulation and pyrolysis. The content of organic acid accounts for the total 5-10% of the mass, and the dispersant accounts for 40-50% of the total mass; the ball milling time is 3-5 hours, and the rotation speed is 300-500r / min.

[0019] (2) Add SiOx / C material, graphite, additives, resin and curing agent into the reaction kettle, mix well, and then prepare SiOx / C surface-coated graphite negative electrode material through spray granulation, high-temperature pyrolysis, and classification screening process , the mass ratio of the SiOx / C material to graphite, additives, and resin is 1:1.5~2:1~1.5:1~2.5, the particle size of graphite is 2~10um, and the curing agent accounts for 3~5 of the total...

Embodiment 1

[0024] A preparation method of SiOx / C surface-coated graphite negative electrode material, the specific steps are as follows:

[0025] (1) According to the mass ratio of SiOx to asphalt, acetic acid, and deionized water as 1:1:0.2:2, add it to the ball mill tank, then seal it, and ball mill it. The time of ball milling is 3 hours, and the speed is 300 r / min. The mixture was taken out, and then granulated by a spray granulation dryer, wherein the temperature of the air inlet was 200°C, and the temperature of the air outlet was 120°C. The temperature for pyrolysis was firstly kept at 300°C for 3h, then at 700°C for 2h, the heating rate was 5°C / min, and nitrogen atmosphere.

[0026] (2) In the reactor, mix the prepared SiOx / C material with graphite, pitch, and epoxy resin in an ethanol solution at a mass ratio of 1:2:1:1, and then heat it to 150°C. And add trimethylhexamethylenediamine curing agent accounting for 5% of the total mass, continue to stir until the mixture is unifor...

Embodiment 2

[0028] A preparation method of SiOx / C surface-coated graphite negative electrode material, the specific steps are as follows:

[0029] (1) Except that the organic acid used was citric acid solution, the ball milling time was 5 hours, and the pyrolysis temperature was firstly kept at 300°C for 3h, and then kept at 800°C for 2h, the proportions of other parameters were the same as in Example 1.

[0030] (2) Except that the resin used is phenolic resin, the heating temperature is 200°C, the curing agent is hexamethylenetetramine, the inlet and outlet temperatures of the spray granulation are 200°C and 150°C, and the pyrolysis temperature is 900°C, etc. Parameters are consistent with Example 1. Such as figure 2 Shown is the X-ray diffraction pattern of the sample prepared in this embodiment.

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Abstract

The invention discloses a preparation method of an SiOx/C surface-coated graphite cathode material. The preparation method comprises the steps of preparing an SiOx/C material precursor by taking SiOx, asphalt and an organic acid solution as raw materials, adding graphite, and preparing a sample by spray granulation and high-temperature pyrolysis by an additive, resin and a curing agent. According to the preparation method, a volume effect of a silicon material can be effectively alleviated in charging and discharging processes, so that the cycling stability is improved; the first cycling efficiency of the silicon material is 82.42% and the reversible specific capacity is 488.2mAh/g at 0.1C multiplying power; and a framework formed by utilizing solidification of the resin can effectively avoid adhesion and agglomeration between grains in a carbonization process of the additive, so that the prepared material has the characteristics of good dispersity and good uniformity and has the advantages of mass production and low cost.

Description

technical field [0001] The invention relates to a preparation method of a negative electrode material, in particular to a preparation method of a SiOx / C surface-coated graphite negative electrode material. Background technique [0002] In recent years, with the rapid development of electric vehicles, higher requirements have been put forward for lithium-ion batteries. However, the traditional graphite-based anode materials are difficult to meet the requirements of high energy density and high output power due to their specific capacity of 372mAh / g. need. At the same time, silicon material has the highest theoretical specific capacity of 4200mAh / g, making it the most likely anode material to replace graphite. However, the volume expansion effect of the silicon negative electrode material is as high as 300% during the cycle, which easily leads to the pulverization and fragmentation of the electrode material, thereby reducing the cycle life of the battery. Compared with pure ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/48H01M4/62H01M10/0525
CPCH01M4/366H01M4/48H01M4/625H01M4/628H01M10/0525Y02E60/10
Inventor 李亚飞贺劲鑫郑媛媛靳承铀薛驰缪永华
Owner ZHONGTIAN ENERGY STORAGE TECH
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