Composite electrode particles coated with silicon particles, carbon layers, and zinc oxide layers

Abstract

A composite electrode particle is provided that is coated with a silicon particle, a carbon layer, and a zinc oxide layer. The present invention relates to a porous carbon particle having a plurality of holes on its surface, an amorphous carbon layer covering the outer surface of the porous carbon particle, and a silicon oxide (SiO x ) layer, and a zinc oxide layer 37 which is a continuous structure formed of a plurality of zinc oxide particles and which covers the outer periphery of the amorphous carbon layer and which generates a good spreading effect to protect other particles in the inner layer.

Description

[Technical field]

[0001] The present invention relates to an electrode particle, and more particularly to a composite electrode particle coated with a granular silicon structure, a carbon layer and zinc oxide. [Background technology]

[0002] The battery is composed of a positive electrode and a negative electrode, the negative electrode mainly includes a negative electrode substrate and a negative electrode slurry layer coated on the negative electrode substrate, the negative electrode slurry layer includes a negative electrode slurry having a binder and a plurality of negative electrode particles. The negative electrode particles are mainly used in the negative electrode of solid or semi-solid batteries. The negative electrode particles have conductive properties or conductivity, which allow free electrons to move in the negative electrode slurry and prevent excessive energy consumption due to internal resistance, thereby achieving the purpose of effective electrical conduction. Summary of the Invention [Problem to be solved by the invention]

[0003] The negative electrode particles are distributed in the negative electrode slurry, and the outer surfaces of these negative electrode particles are covered with silicon particles. However, during the battery reaction process, when lithium ions enter the silicon particles and the volume of the silicon particles expands, the silicon particles can expand up to 400 times their original size, causing a large change in the volume of the entire negative electrode particle. This huge volume expansion damages the entire negative electrode particle and reduces the battery performance.

[0004] Therefore, the present inventors believed that the above-mentioned shortcomings could be improved, and after extensive research, they proposed a design that improves the volume expansion of the negative electrode particles, thereby enabling the negative electrode of conventional solid-state batteries to have higher battery performance, thereby further improving the performance of the battery.

[0005] The present invention was made by the inventors through intensive research in consideration of the above problems, and its object is to provide a composite electrode particle coated with silicon particles, a carbon layer, and a zinc oxide layer. [Means for solving the problem]

[0006] In order to solve the above problems, a composite electrode particle coated with a silicon particle, a carbon layer, and a zinc oxide layer according to one embodiment of the present invention is used in an electrode of a solid or semi-solid battery, Porous carbon particles having a plurality of holes on the surface thereof; an amorphous carbon layer that covers an outer surface of the porous carbon particle and has a continuous structure formed of amorphous carbon, the amorphous carbon layer having good electrical conductivity, suppressing expansion of the composite electrode particle, and preventing the composite electrode particle from bursting when lithium ions are filled into the composite electrode particle; a plurality of silicon particles distributed within the amorphous carbon layer, the outer surfaces of a portion of the plurality of silicon particles being covered with a silicon oxide (SiOx) layer; A zinc oxide layer covers the outer periphery of the amorphous carbon layer, the zinc oxide layer having a structure formed of a plurality of zinc oxide particles, and having good electrical conductivity and ductility equivalent to that of a metal, and even if lithium ions are filled into the silicon particles and the silicon particles expand, the zinc oxide layer protects other particles inside due to its ductility. Effect of the Invention

[0007] Since the present invention is configured as described above, it has the following advantages. In the present invention, the porous carbon particles are coated with a plurality of silicon particles and an amorphous carbon layer. The silicon particles coated with the silicon oxide layer have a small expansion coefficient and suitable bonding properties, so that the expansion of the overall volume of the composite electrode particles can be suppressed and the composite electrode particles can be prevented from being damaged. The amorphous carbon layer itself has a suitable electrical conductivity, so that the expansion of the composite electrode particles can be suppressed and the volume can be prevented from being excessively expanded when lithium ions are filled into the silicon particles. The amorphous carbon layer is further coated with the zinc oxide layer, which has good electrical conductivity and ductility equivalent to that of metal, so that even if the silicon particles expand when lithium ions are filled into the silicon particles, the zinc oxide layer protects the other particles inside with its good ductility. In this way, the present invention significantly reduces the crushing rate of the composite electrode particles through the above-mentioned multi-layer coating structure.

[0008] Other objects, configurations and effects of the present invention will become apparent from the following detailed description of the preferred embodiments of the present invention. [Brief description of the drawings]

[0009] [Figure 1] 1 is a schematic cross-sectional view showing a composite electrode particle according to an embodiment of the present invention. [Diagram 2] 1 is a schematic diagram of a porous carbon particle according to an embodiment of the present invention; [Diagram 3] 1 is a schematic diagram showing the configuration and partial enlargement of a composite electrode particle according to an embodiment of the present invention; [Figure 4] 1 is a schematic diagram illustrating a silicon particle and a silicon oxide layer according to an embodiment of the present invention. [Diagram 5] 2 is a schematic diagram showing an electrode particle coated with carbon nanotubes in accordance with an embodiment of the present invention; [Figure 6] 2 is an application example showing a composite electrode particle coated with silicon particles, a carbon layer, and a zinc oxide layer according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The present invention will be described below through the embodiments of the invention, but the following embodiments do not limit the invention according to the claims. In addition, not all of the combinations of features described in the embodiments are necessarily essential to the solution of the invention.

[0011] First, an example of a specific embodiment of a composite electrode particle coated with silicon particles, a carbon layer, and a zinc oxide layer according to the present invention will be described with reference to FIGS. 1 to 6. FIG.

[0012] The composite electrode particles coated with silicon particles, carbon layer and zinc oxide layer according to the present invention are mainly used in electrodes of solid or semi-solid batteries, especially in the negative electrode 10 of the solid or semi-solid battery. The negative electrode 10 includes a negative electrode substrate 11 for mounting the material of the negative electrode 10, and a negative electrode slurry layer 13 applied to the negative electrode substrate 11. The negative electrode slurry layer 13 includes a negative electrode slurry 12 as a binder and a plurality of composite electrode particles 40 (see FIG. 9). The weight percentage of the total weight of the plurality of composite electrode particles 40 in the negative electrode slurry layer 13 is in the range of 90wt% to 99wt%. The particle size of the composite electrode particles 40 is in the range of 5μm to 12μm.

[0013] The composite electrode particle 40 is composed of the following elements:

[0014] The <porous carbon particles 30> have a size in the range of 5 μm to 10 μm, and have a plurality of holes 31 on the surface (see FIG. 2). The porous carbon particles 30 are made of graphite or the like.

[0015] The <amorphous carbon layer 36> covers the outer surface of the porous carbon particle 30. The amorphous carbon layer 36 is a continuous structure formed of amorphous carbon, that is, a film layer having a smooth surface. The radial thickness of the amorphous carbon layer 36 is in the range of 10 nm to 20 nm, and the amorphous carbon layer 36 has a suitable electrical conductivity, suppresses the expansion of the composite electrode particle 40, and can prevent the composite electrode particle 40 from bursting due to the expansion of volume caused by filling the composite electrode particle 40 with lithium ions. The amorphous carbon of the amorphous carbon layer 36 may be hard carbon or soft carbon formed by sintering deesterification of an organic resin system, or hard carbon or soft carbon formed by sintering deesterification of an organic carbohydrate. The amorphous carbon layer 36 covering the outer surface of the porous carbon particle 30 achieves a protective effect.

[0016] The plurality of silicon particles 32 are distributed in the amorphous carbon layer 36. In this case, as shown in FIG. 1, FIG. 3 and FIG. 4, the outer surfaces of some of the plurality of silicon particles 32 are covered with silicon oxide (SiO x ) layer 322. The silicon particles 32 are in a discontinuous distribution structure, and the silicon particles 32 located outside the amorphous carbon layer 36 form an island-like distribution structure having a plurality of protruding portions. The silicon particles 32 located inside the amorphous carbon layer 36 are attached to the outer surface of the porous carbon particle 30. The silicon particles 32 located between the outside and inside of the amorphous carbon layer 36 are suspended in the amorphous carbon layer 36 and do not contact the porous carbon particle 30.

[0017] The size of each of the silicon particles 32 ranges between 10 nm and 30 nm. The thickness of the silicon oxide layer 322 is less than 3 nm. The silicon oxide layer 322 is formed during the grinding or burning process of the composite electrode particles 40. The weight ratio of the total weight of the silicon particles 32 and the porous carbon particles 30 ranges between 1:9 and 1:12.

[0018] During the reaction process of the battery, lithium ions enter the silicon particles 32, causing the volume of the silicon particles 32 to expand, and the silicon particles 32 may expand to 400 times their original size, resulting in a large change in volume of the composite electrode particle 40. The multiple holes 31 of the porous carbon particle 30 are used to accommodate the expanded silicon particles 32.

[0019] Although the conductivity of the silicon oxide layer 322 is lower than that of the silicon particles 32, when lithium ions pass through the silicon particles 32 and the volume of the silicon particles 32 expands, the huge volume expansion destroys the composite electrode particles 40. However, since the silicon oxide layer 322 has a small expansion coefficient and suitable bonding properties, it is possible to suppress the volume expansion of the entire composite electrode particle 40 and prevent damage due to excessive expansion.

[0020] A zinc oxide (ZnO) layer 37 covers the outer periphery of the amorphous carbon layer 36. The zinc oxide layer 37 is a continuous structure formed of a plurality of zinc oxide particles 38, i.e., a film layer having a smooth surface, and the whole of the zinc oxide layer 37 forms the composite electrode particle 40. The radial thickness of the zinc oxide layer 37 is in the range of 8 nm to 12 nm, and the zinc oxide layer 37 has good electrical conductivity and ductility equivalent to that of a metal. Even if the silicon particle 32 expands after lithium ions are filled into the silicon particle 32, the zinc oxide layer 37 protects other particles inside due to its good ductility, and maintains the integrity of the composite electrode particle 40.

[0021] The present invention further includes a plurality of carbon nanotubes (CNTs) 42 that cover the outer periphery of the composite electrode particle 40, forming a carbon nanotube-covered electrode particle 45 (see FIG. 5). The length of the carbon nanotubes 42 is less than 5 μm.

[0022] Carbon nanotubes are good conductive materials and when attached to the composite electrode particles 40, they form a wool-like structure (see FIG. 5). The carbon nanotubes 42 are used to increase the electronic conductivity and conduct electrons across the composite electrode particles 40. Carbon nanotubes are extremely conductive, and lithium ions pass through the carbon nanotubes 40 and are conducted between different composite electrode particles 40 throughout the electrode, thus increasing the overall conductivity of the electrode.

[0023] The weight ratio of the total weight of the carbon nanotubes 42 to the composite electrode particles 40 ranges from 1:99 to 0.2:99.8.

[0024] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means devised in different embodiments are also included in the technical scope of the present invention. [Explanation of symbols]

[0025] 10 negative electrode 11 Negative substrate 12 Anode slurry 13 Negative electrode slurry layer 30 Porous carbon particles 31 holes 32 Silicon particles 36 Amorphous carbon layer 37 Zinc oxide layer 38 Zinc oxide particles 40 Composite electrode particles 42 Carbon nanotubes 45 Electrode particles coated with carbon nanotubes 322 Silicon oxide layer

Claims

1. A composite electrode particle coated with a silicon particle, a carbon layer, and a zinc oxide layer, which is used in an electrode of a solid or semi-solid battery, Porous carbon particles having a plurality of holes on the surface thereof; an amorphous carbon layer that covers an outer surface of the porous carbon particle and has a continuous structure formed of amorphous carbon, the amorphous carbon layer having good electrical conductivity, suppressing expansion of the composite electrode particle, and preventing the composite electrode particle from bursting when lithium ions are filled into the composite electrode particle; a plurality of silicon particles distributed within the amorphous carbon layer; a zinc oxide layer covering the outer periphery of the amorphous carbon layer, the zinc oxide layer having a structure formed of a plurality of zinc oxide particles, having good electrical conductivity and ductility equivalent to that of a metal, and protecting other particles inside due to the ductility of the zinc oxide layer even when the silicon particles expand when lithium ions are filled into the silicon particles.

2. 2. The composite electrode particle coated with silicon particles, a carbon layer and a zinc oxide layer according to claim 1, characterized in that the silicon particles have a discontinuous distribution structure, the silicon particles located outside the amorphous carbon layer form an island-like distribution structure having a plurality of protruding portions, the silicon particles located inside the amorphous carbon layer are attached to the outer surfaces of the porous carbon particles, and the silicon particles located between the outer and inner sides of the amorphous carbon layer are suspended in the amorphous carbon layer and do not contact the porous carbon particles.

3. The composite electrode particle coated with silicon particles, a carbon layer and a zinc oxide layer according to claim 1, characterized in that the particle size of the porous carbon particles is in the range of 5 μm to 10 μm.

4. The composite electrode particle coated with silicon particles, a carbon layer and a zinc oxide layer as described in claim 1, characterized in that the size of each of the silicon particles ranges between 10 nm and 30 nm, and the thickness of the silicon oxide layer is less than 3 nm.

5. The composite electrode particle coated with silicon particles, a carbon layer, and a zinc oxide layer according to claim 1, characterized in that a weight ratio of the total weight of the plurality of silicon particles and the weight of the porous carbon particles is in a range of between 1:9 and 1:

12.

6. 2. The composite electrode particle coated with a silicon particle, a carbon layer and a zinc oxide layer as claimed in claim 1, wherein the radial thickness of the amorphous carbon layer is in the range of between 10 nm and 20 nm.

7. 2. The composite electrode particle coated with silicon particles, a carbon layer, and a zinc oxide layer according to claim 1, characterized in that the amorphous carbon of the amorphous carbon layer is selected from hard carbon or soft carbon formed by sintering deesterification of an organic resin system, or hard carbon or soft carbon formed by sintering deesterification of an organic carbohydrate.

8. 2. The composite electrode particle coated with a silicon particle, a carbon layer and a zinc oxide layer according to claim 1, characterized in that the radial thickness of the zinc oxide layer is in the range of between 8 nm and 12 nm.

9. 2. The composite electrode particle coated with silicon particles, a carbon layer and a zinc oxide layer according to claim 1, wherein the composite electrode particle is used in a negative electrode of a solid or semi-solid battery.

10. A composite electrode particle coated with silicon particles, a carbon layer, and a zinc oxide layer as described in claim 1, further comprising a plurality of carbon nanotubes coating the outer periphery of the composite electrode particle, thereby forming an electrode particle coated with carbon nanotubes.

11. A composite electrode particle coated with silicon particles, a carbon layer, and a zinc oxide layer as described in claim 10, characterized in that each of the carbon nanotubes has a length of less than 5 μm and forms a wool-like structure when attached to the composite electrode particle, and the carbon nanotubes are used to increase electronic conductivity.

12. The composite electrode particle coated with silicon particles, a carbon layer, and a zinc oxide layer as described in claim 10, characterized in that the weight ratio of the total weight of the plurality of carbon nanotubes to the weight of the composite electrode particle is in the range of between 1:99 and 0.2:99.8.

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