Preparation method for improving carbon coating quality of novel lithium battery negative electrode material

Abstract

The invention discloses a preparation method for improving the carbon coating quality of a novel lithium battery negative electrode material, which comprises the following steps: S1, organic acid modification: dipping a silicon-carbon precursor formed by depositing silicon in pores of porous carbon in an organic acid solution, and carrying out modification treatment; s2, spray drying: carrying out spray drying treatment on the modified silicon-carbon precursor; and S3, carbon coating: performing pyrolysis treatment on the modified silicon-carbon precursor to form a carbon coating layer, then introducing carbon-containing gas for chemical vapor deposition, and performing secondary carbon coating.

Description

Technical Field

[0001] The present invention relates to the technical field of a preparation method for improving the carbon coating quality of a novel lithium battery negative electrode material, and in particular to a preparation method for improving the carbon coating quality of a novel lithium battery negative electrode material. Background Art

[0002] At present, new silicon-carbon materials have broad application prospects in the field of lithium-ion battery negative electrode materials due to their high energy density, long cycle life and good thermal stability. However, the carbon layer of the new silicon-carbon negative electrode material is uneven, and it is easy to fall off and react with the electrolyte during the charge and discharge process, resulting in a decrease in cycle performance. In order to improve its cycle stability, carbon coating technology is usually used to alleviate it. Existing carbon coating methods mainly include chemical vapor deposition (CVD), physical vapor deposition (PVD) and pyrolytic carbon coating. Although these methods can improve the performance of silicon-carbon materials to a certain extent, there are still problems such as uneven coating quality and weak bonding force. Uneven coating quality: Existing carbon coating methods are difficult to ensure the uniformity of the coating, resulting in unstable performance of silicon-carbon materials. Weak bonding force: The bonding force between the coating and the silicon-carbon core is weak, and it is easy to fall off during the cycle, affecting the cycle stability of the material. Summary of the Invention

[0003] In order to solve certain technical problems existing in the prior art, the purpose of this application is to provide a preparation method for improving the carbon coating quality of new lithium battery negative electrode materials, aiming to solve technical problems such as poor quality of the carbon coating layer, uneven coating, and weak bonding between the coating layer and the material core during the preparation process of new silicon-carbon materials.

[0004] In order to solve the above existing technical problems, one of the objectives of this application is achieved by adopting the following technical solutions:

[0005] A preparation method for improving the carbon coating quality of a novel lithium battery negative electrode material comprises the following steps:

[0006] S1, organic acid modification: immersing the silicon-carbon precursor formed by depositing silicon in the pores of the porous carbon in an organic acid solution for modification;

[0007] S2, spray drying: spray drying the modified silicon-carbon precursor;

[0008] S3, carbon coating: the modified silicon-carbon precursor is pyrolyzed to form a carbon coating layer, and then a carbon-containing gas is introduced to perform chemical vapor deposition for secondary carbon coating.

[0009] Furthermore, in step S1, organic acid modification is performed: a suitable organic acid is selected and dissolved in an appropriate amount of solvent to form an organic acid solution, and a silicon-carbon precursor formed by depositing silicon in the pores of the porous carbon is added to the organic acid solution, and the organic acid molecules interact with the surface of the silicon-carbon precursor through chemical reaction or physical adsorption, thereby improving its surface properties.

[0010] Furthermore, in step S2, spray drying: the mixed solution is spray dried.

[0011] Furthermore, in step S3, carbon coating is performed: the modified silicon-carbon precursor is placed in a high-temperature furnace for pyrolysis treatment, so that the carbon-containing precursor is pyrolyzed to form a carbon coating layer. The pyrolysis temperature and time need to be optimized according to specific experimental conditions, and then a carbon-containing gas is introduced for re-coating.

[0012] Furthermore, in step S1, the organic acid is, for example, citric acid or tartaric acid.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] (1) By introducing organic acid as a modifier, the formation process of the carbon coating layer is optimized, the uniformity and bonding strength of the coating layer are improved, thereby enhancing the cycle stability and electrochemical performance of the silicon-carbon material. DETAILED DESCRIPTION

[0015] Below, the present application is further described in conjunction with specific implementation methods. It should be noted that, under the premise of no conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0016] In the description of this application, it should be understood that the terms "up", "down", "left", "right", etc. indicate directions or positional relationships, which are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on this application.

[0017] The terms "first", "second", etc. in this application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application can be implemented in an order other than those described here, and the objects distinguished by "first", "second", etc. are generally of one type, and the number of objects is not limited. For example, the first object can be one or more. In addition, "and / or" in the specification and claims represents at least one of the connected objects, and the character " / " generally indicates an "or" relationship between the previously associated objects.

[0018] Example 1:

[0019] A preparation method for improving the carbon coating quality of a novel lithium battery negative electrode material comprises the following steps:

[0020] S1, organic acid modification: immersing the silicon-carbon precursor formed by depositing silicon in the pores of the porous carbon in an organic acid solution for modification;

[0021] S2, spray drying: spray drying the modified silicon-carbon precursor;

[0022] S3, carbon coating: the modified silicon-carbon precursor is pyrolyzed to form a carbon coating layer, and then a carbon-containing gas is introduced to perform chemical vapor deposition for secondary carbon coating.

[0023] By introducing an organic acid as a modifier, the formation process of the carbon coating is optimized, thereby improving the overall performance of the silicon-carbon material, especially its cycle stability and electrochemical performance. By introducing an organic acid as a modifier, the present invention optimizes the formation process of the carbon coating and significantly improves the uniformity and bonding strength of the coating. This not only enhances the cycle stability of the silicon-carbon material, but also improves its electrochemical performance. In addition, the method is simple to operate and does not require the introduction of complex additives or additional processing steps, thereby reducing the preparation cost. Compared with the existing technology, it solves the technical problem that "although the performance of the silicon-carbon material can be improved to a certain extent, there are still problems such as uneven quality of the coating and weak bonding strength. Uneven coating quality: The existing carbon coating method is difficult to ensure the uniformity of the coating, resulting in unstable performance of the silicon-carbon material. Weak bonding strength: The bonding strength between the coating and the silicon-carbon core is weak, and it is easy to fall off during the cycle, affecting the cyclic stability of the material."

[0024] Furthermore, in step S1, organic acid modification is performed: a suitable organic acid is selected and dissolved in an appropriate amount of solvent to form an organic acid solution, and a silicon-carbon precursor formed by depositing silicon in the pores of the porous carbon is added to the organic acid solution. Through chemical reaction or physical adsorption, the organic acid molecules interact with the surface of the silicon-carbon precursor, thereby improving its surface properties.

[0025] Furthermore, in step S2, spray drying: the mixed solution is spray dried.

[0026] Furthermore, in step S3, carbon coating is performed: the modified silicon-carbon precursor is placed in a high-temperature furnace for pyrolysis to form a carbon coating layer. The pyrolysis temperature and time need to be optimized according to specific experimental conditions. Then, a carbon-containing gas is introduced for re-coating. Optimizing the pyrolysis conditions can ensure the uniformity and bonding strength of the carbon coating layer.

[0027] Furthermore, in step S1, the organic acid is, for example, citric acid or tartaric acid.

[0028] The above-mentioned embodiments are only preferred embodiments of the present application and cannot be used to limit the scope of protection of the present application. Any non-substantial changes and replacements made by technicians in this field based on the present application shall fall within the scope of protection required by the present application.

Claims

1. A preparation method for improving the carbon coating quality of a new lithium battery negative electrode material, characterized in that: The following steps are involved: S1, organic acid modification: immersing the silicon-carbon precursor formed by depositing silicon in the pores of the porous carbon in an organic acid solution for modification; S2, spray drying: spray drying the modified silicon-carbon precursor; S3, carbon coating: the modified silicon-carbon precursor is pyrolyzed to form a carbon coating layer, and then a carbon-containing gas is introduced to perform chemical vapor deposition for secondary carbon coating.

2. The method for improving the carbon coating quality of a novel lithium battery negative electrode material according to claim 1, characterized in that: In step S1, organic acid modification: a suitable organic acid is selected and dissolved in an appropriate amount of solvent to form an organic acid solution, and a silicon-carbon precursor formed by depositing silicon in the pores of the porous carbon is added to the organic acid solution. Through chemical reaction or physical adsorption, the organic acid molecules interact with the surface of the silicon-carbon precursor, thereby improving its surface properties.

3. The method for improving the carbon coating quality of a novel lithium battery negative electrode material according to claim 2, characterized in that: In step S2, spray drying: the mixed solution is spray dried.

4. The method for improving the carbon coating quality of a novel lithium battery negative electrode material according to claim 3, characterized in that: In step S3, carbon coating: the modified silicon-carbon precursor is placed in a high-temperature furnace for pyrolysis treatment, so that the carbon-containing precursor is pyrolyzed to form a carbon coating layer. The pyrolysis temperature and time need to be optimized according to specific experimental conditions, and then a carbon-containing gas is introduced for re-coating.

5. The method for improving the carbon coating quality of a novel lithium battery negative electrode material according to claim 4, characterized in that: In step S1 , the organic acid is, for example, citric acid or tartaric acid.