Method for manufacturing composite electrode particles coated with composite silicon particles, carbon layer and zinc oxide

Abstract

The invention discloses a method for manufacturing composite electrode particles coated with composite silicon particles, a carbon layer and zinc oxide, which comprises the following steps of: 500, fully mixing and grinding a plurality of silicon particles, a high polymer material, asphalt and an alcohol solution by using a grinding machine; a part of the silicon particles can generate a silicon oxide layer to coat the surfaces of the silicon particles so as to form composite silicon particles; step 510, adding a plurality of porous carbon particles into the grinding machine, and continuously mixing and grinding; step 520, putting the materials into a vacuum concentrator to obtain mixture powder; step 530, placing the mixture powder into a sintering furnace for atmosphere sintering to integrally form a first particle; and step 540, mixing a plurality of zinc oxide particles and the plurality of first particles by using a rolling type mixer, so that the outer surface of each first particle is coated by a zinc oxide layer formed by the plurality of zinc oxide particles, and the composite electrode particles are integrally formed.

Description

Technical Field

[0001] This invention relates to the field of battery electrode materials technology, and in particular to a method for manufacturing composite electrode particles having composite silicon particles, a carbon layer, and a zinc oxide coating. Background Technology

[0002] A battery consists of a positive electrode and a negative electrode. The negative electrode mainly comprises a negative electrode substrate and a negative electrode slurry layer coated on the substrate. The negative electrode slurry layer contains a negative electrode slurry with a binder and multiple negative electrode particles. These negative electrode particles are primarily used in general solid-state or near-solid-state batteries and must possess conductivity or enhanced conductivity to allow free electrons to migrate within the negative electrode slurry, preventing excessive energy loss due to internal resistance and thus achieving effective conductivity. Therefore, the use of specific conductive materials to adjust the conductivity of the negative electrode particles is crucial during manufacturing.

[0003] The negative electrode particles are distributed within the negative electrode slurry, and their outer surface is coated with silicon particles. During the battery reaction, lithium ions enter the silicon particles, causing them to expand in volume, potentially up to four times their original size. This results in a significant change in the overall volume of the negative electrode particles. Such massive volume expansion can damage the negative electrode particles, leading to a decrease in battery performance.

[0004] Therefore, this study aims to propose a novel design that can improve the volume expansion problem of negative electrode particles, enabling the negative electrode of existing solid-state batteries to have higher battery performance and further improve the overall efficiency of the battery.

[0005] Therefore, existing technologies have shortcomings and need to be improved. Summary of the Invention

[0006] This invention aims to address the problems existing in the prior art by proposing a method for manufacturing composite electrode particles with composite silicon particles, a carbon layer, and zinc oxide coating. This method involves coating porous carbon particles with multiple silicon particles and a carbon layer. The silicon particles coated with the silicon oxide layer have a low coefficient of thermal expansion and good adhesion, which can suppress the volume expansion of the entire electrode particle and prevent breakage due to excessive expansion. Furthermore, the carbon layer itself has good conductivity and can suppress electrode particle expansion, preventing excessive volume expansion caused by lithium ion embedding in the silicon particles. The zinc oxide layer has good conductivity and metallic ductility; when lithium ions embed in the silicon particles causing expansion, the zinc oxide layer can produce a good ductile effect, thereby protecting the other particles in the inner layer. This invention, through its multi-layer coating design, can effectively reduce electrode particle breakage.

[0007] To achieve the above objectives, this invention proposes a method for manufacturing composite electrode particles having a composite silicon particle layer, a carbon layer, and a zinc oxide coating, wherein the composite electrode particles exist in the electrode in the form of multiple composite electrode particles; the method includes the following steps: Step 500: Add multiple silicon particles, polymer materials, asphalt and alcohol solution to a grinder, mix and grind thoroughly; during the mixing and grinding process, some silicon particles undergo disproportionation reaction, forming a partially oxidized unsaturated silicon oxide layer on their surface, forming composite silicon particles; The silicon oxide layer has a low coefficient of thermal expansion and good adhesion, which can suppress the volume expansion of the entire particle and prevent the electrode particles from breaking due to excessive expansion; the chemical formula of the silicon oxide layer is SiO2. x Where 0 < x < 2. Preferably, the value of x is between 0.1 and 0.8.

[0008] Step 510: Add multiple porous carbon particles to a grinder and continue mixing and grinding; wherein the porous carbon particles have multiple pores on their surface (e.g., Figure 5 As shown, these multiple pores can absorb expanding silicon particles; Step 520: Remove the above material from the grinder and place it in a vacuum concentrator to remove the alcohol solution, obtaining a mixture powder; Step 530: The mixture powder is placed in a sintering furnace for atmosphere sintering. During the sintering process, the asphalt and polymer materials in the mixture powder form a carbon layer that coats the outer surface of each porous carbon particle, while multiple silicon particles and composite silicon particles are distributed within each carbon layer, forming a first particle. Multiple first particles exist in the sintering furnace. The multiple silicon particles and composite silicon particles are not continuously distributed, but are distributed in an island-like manner on the porous carbon particles or attached to their outer surface. Another part of the silicon particles and composite silicon particles are suspended in the carbon layer, separated from the porous carbon particles. Step 540: Take multiple zinc oxide particles and multiple first particles and mix them using a rolling mixer so that the outer surface of each first particle is covered with a zinc oxide layer formed by multiple zinc oxide particles, forming a composite electrode particle; the zinc oxide particles are distributed in an island-like pattern. The present invention also includes the following steps: Step 550: Multiple composite electrode particles and multiple carbon nanotubes (CNTs) are placed in a dry mixer and mixed and stirred; so that each composite electrode particle is coated with multiple carbon nanotubes to form carbon nanotube-coated electrode particles; wherein when the carbon nanotubes are attached to the composite electrode particles, they form a yarn-like shape; the carbon nanotubes are used to increase electronic conductivity. Attached Figure Description

[0009] Figure 1 This invention is illustrated in the flowchart.

[0010] Figure 2 This diagram illustrates the operation of steps 500 to 530 of the present invention.

[0011] Figure 3 This diagram illustrates the operation of steps 540 to 550 of the present invention.

[0012] Figure 4 This shows a cross-sectional view of the structure of the present invention.

[0013] Figure 5 This diagram shows the structure of the porous carbon of the present invention.

[0014] Figure 6 This shows an enlarged view of the structure of the composite electrode particles of the present invention.

[0015] Figure 7 This diagram shows the structure of the silicon particles coated with a silicon oxide layer according to the present invention.

[0016] Figure 8 This diagram shows the structure of the electrode particles coated with carbon nanotubes according to the present invention.

[0017] Figure 9 Examples of applications of the present invention are shown.

[0018] Among them, the negative electrode is 10, the negative electrode substrate is 11, the negative electrode slurry is 12, the negative electrode slurry layer is 13, the porous carbon particles are 30, the pores are 31, the composite silicon particles are 32, the mixed powder is 50, the carbon layer is 36, the zinc oxide layer is 37, the zinc oxide particles are 38, the composite electrode particles are 40, the carbon nanotubes are 42, the electrode particles coated with carbon nanotubes are 45, the grinding mill is 100, the vacuum concentrator is 150, the sintering furnace is 200, the dry mixer is 250, the rolling mixer is 300, the silicon particles are 321, the silicon oxide layer is 322, the polymer material is 323, and the first particle is 361. Detailed Implementation

[0019] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0020] Please see Figures 1 to 9 This invention illustrates a method for manufacturing composite electrode particles having a composite silicon particle, a carbon layer, and a zinc oxide coating, wherein the composite electrode particles are presented in an electrode as a plurality of composite electrode particles 40. This invention is particularly applicable to the negative electrode 10 of such solid-state or solid-like batteries. Figure 9 As shown, the negative electrode 10 includes: a negative electrode substrate 11, which is a carrier plate for supporting the negative electrode 10; and a negative electrode slurry layer 13 coated on the negative electrode substrate 11, the negative electrode slurry layer 13 including: a negative electrode slurry 12 as a binder. The total weight of the plurality of composite electrode particles 40 accounts for 90wt% to 99wt% of the electrode slurry layer (especially the negative electrode slurry layer). The overall particle size of the composite electrode particles 40 of the present invention is between 5 micrometers and 12 micrometers.

[0021] like Figures 1 to 3 As shown, the method of the present invention, used to manufacture the composite electrode particle 40, includes the following steps: Step 500: Take multiple silicon particles 321, polymer material 323, asphalt 324, and alcohol solution 325, and thoroughly mix and grind the above four materials using a grinder 100. The grinder 100 is a wet grinder. The grinding time is 4-6 hours, and the rotation speed of the grinder 100 is 2600 rpm-3000 rpm. Preferably, the alcohol solution 325 is isopropanol or ethanol. The polymer material 323 is selected from at least one of sodium dodecyl sulfate (SDS), polyvinylpyrrolidone (PVP), carboxymethyl cellulose (CMC), or carboxyl long-chain polymers or some phenolic resins.

[0022] The weight ratio of silicon particles 321, polymer material 323, and asphalt 324 is 8-9:0.2-1:0.2-1; the weight ratio of the solid composed of silicon particles 321, polymer material 323, and asphalt 324 to the alcohol solution 325 is 4:6.

[0023] like Figure 7 As shown, during the mixing and grinding process, some of the silicon particles 321 undergo a disproportionation reaction to generate silicon monoxide (SiO2). x A layer 322 coats the surface of the silicon particle 321, forming a composite silicon particle 32. The size of the composite silicon particle 32 is between 10 nanometers and 30 nanometers. The thickness of the silicon oxide layer 322 is less than 3 nanometers. The chemical formula of the silicon oxide layer is SiO2. x Where 0 < x < 2. Preferably, the value of x is between 0.1 and 0.8.

[0024] The conductivity of the silicon oxide layer 322 is lower than that of the silicon particle 321. However, when lithium ions pass through the silicon particle 321, it causes the silicon particle 321 to expand significantly in volume. Such a large volume expansion would cause the entire electrode particle to break. However, the silicon oxide layer 322 has a smaller coefficient of expansion and better adhesion, so it can suppress the volume expansion of the entire particle and prevent the electrode particle from expanding excessively and breaking.

[0025] Step 510: Add multiple porous carbon particles 30 to the grinder 100 and continue to mix and grind for 0.5 hours to 2 hours at a speed of 1800 rpm to 2200 rpm.

[0026] The weight ratio of the total weight of the porous carbon particles 30 to the total weight of the plurality of silicon particles 321 is 8~9.5:0.5~2. The porous carbon particles 30 have a plurality of pores 31 on their surface (e.g., ...). Figure 5 As shown, the multiple pores 31 can absorb the expanded silicon particles 321. After grinding, the particle size of the porous carbon particles 30 is between 5 micrometers and 10 micrometers.

[0027] Step 520: The above material is removed from the grinding mill 100 and placed into a vacuum concentrator 150 to remove the alcohol solution 325, thereby obtaining a mixture powder 50. The vacuum concentrator 150 is a water bath vacuum concentrator, and the water bath temperature is 20°C to 45°C.

[0028] Step 530: The mixture powder 50 is placed in a sintering furnace 200 for atmosphere sintering, wherein the sintering temperature is 980°C ~ 1100°C and the sintering time is 6 ~ 8 hours. Figure 4 and Figure 6 As shown, during the atmosphere sintering process, the pitch 324 and polymer material 323 in the mixture powder 50 form a carbon layer 36 (excess non-carbon elements are removed during sintering) coating the outer surface of each porous carbon particle 30. Multiple silicon particles 321 and multiple composite silicon particles 32 are distributed within each carbon layer 36, collectively forming a first particle 361. Multiple first particles 361 are present within the sintering furnace 200. The atmosphere sintering can be argon (Ar) atmosphere sintering or nitrogen (N2) atmosphere sintering. The pitch 324 and polymer material 323 facilitate the adhesion of the multiple silicon particles 321 and composite silicon particles 32 to each porous carbon particle 30. The silicon particles 321 and composite silicon particles 32 are not distributed continuously. The silicon particles 321 and composite silicon particles 32 are distributed in an island-like manner on the porous carbon particles 30, or are attached to the outer surface of the porous carbon particles 30. Another part of the silicon particles 321 and composite silicon particles 32 will be suspended in the carbon layer and separated from the porous carbon particles.

[0029] The carbon layer 36 itself has good conductivity and can suppress the expansion of the entire electrode particle to avoid excessive volume expansion caused by lithium ions filling the silicon particle 32, which would lead to the breakage of the electrode particle.

[0030] Step 540: Take multiple zinc oxide particles 38 and multiple first particles 361 and mix them using a rolling mixer 300, so that the outer surface of each first particle 361 is coated with a zinc oxide layer 37 formed by the multiple zinc oxide particles 38, such as... Figure 4 and Figure 6As shown, the composite electrode particles 40 of the present invention are formed as a whole. The zinc oxide particles 38 are distributed in an island-like pattern. The mixing time of the rolling mixer 300 is 0.5 hours to 2 hours, and the rotation speed is 200 rpm to 350 rpm; the machine is filled with multiple zirconium beads, the zirconium bead filling rate is 30% to 50%, and the particle size of a single zirconium bead is 1.2 mm to 2 mm.

[0031] The zinc oxide layer 37 has good electrical conductivity and metallic ductility. When lithium ions are embedded in the composite silicon particles 32 and cause them to expand, the zinc oxide layer 37 can extend accordingly, protecting the inner particles, maintaining the integrity of the electrode particles 40, and preventing breakage.

[0032] like Figure 3 and Figure 8 As shown, the present invention may further include: Step 550: Multiple composite electrode particles 40 and multiple carbon nanotubes 42 (CNTs) are placed in a dry mixer 250 and mixed and stirred to coat the composite electrode particles 40 with carbon nanotubes 42, forming carbon nanotube-coated electrode particles 45. The length of the carbon nanotubes 42 is less than 5 μm; the weight ratio of the carbon nanotubes 42 to the composite electrode particles 40 is between 1:99 and 0.2:99.8.

[0033] Carbon nanotubes have excellent electrical conductivity and, after attachment, form a "ball of yarn" shape (such as...). Figure 5 It can create high-speed electron channels between particles, enabling lithium ions to be rapidly conducted between composite electrode particles 40 via carbon nanotubes 42, significantly improving the overall conductivity of the electrode.

[0034] This invention involves coating porous carbon particles with multiple unsaturated silicon oxide particles and an amorphous carbon layer. The unsaturated silicon oxide layer, instead of pure silicon, is chosen because it has a lower coefficient of thermal expansion, higher capacity reversibility, and better bonding, thus effectively suppressing the volume expansion of the entire electrode particle and preventing breakage due to excessive expansion. Furthermore, the amorphous carbon layer itself has good conductivity and can suppress the overall expansion of the electrode particle, preventing excessive volume expansion caused by lithium ion embedding in the silicon particles. Simultaneously, the zinc oxide layer possesses good conductivity and metallic ductility; when lithium ions embed in the silicon particles causing expansion, the zinc oxide layer provides good ductility, thereby protecting the other particles in the inner layer. This invention, through its multi-layered coating structure, effectively reduces electrode particle breakage.

[0035] In summary, the advantages of this invention are as follows: porous carbon particles are sequentially coated with silicon particles, a carbon layer, and a zinc oxide layer. The silicon particles, with their surface already covered by the silicon oxide layer, have a low coefficient of thermal expansion and good adhesion, thus suppressing volume expansion. The carbon layer combines high conductivity with expansion buffering capabilities. The zinc oxide layer, utilizing its conductivity and ductility, provides protection during silicon particle expansion. This multi-layer coating works synergistically to significantly reduce the risk of electrode particle breakage and improve the cycle stability and electrochemical performance of the solid-state battery anode.

[0036] The above detailed description is only for one feasible embodiment of the present invention, and this embodiment is not intended to limit the patent scope of the present invention. All equivalent implementations or modifications that do not depart from the spirit of the present invention should be included in the patent scope of the present invention.

Claims

1. A method for manufacturing composite electrode particles having composite silicon particles, a carbon layer, and a zinc oxide coating, characterized in that, The composite electrode particles exist in the electrode in the form of multiple composite electrode particles; the method includes the following steps: Step 500: Multiple silicon particles, polymer materials, asphalt, and alcohol solutions are added to a grinding mill, thoroughly mixed, and ground. During the mixing and grinding process, some silicon particles undergo a disproportionation reaction, forming a partially oxidized unsaturated silicon oxide layer on their surface, thus forming composite silicon particles. The chemical formula of this silicon oxide layer is SiO₂. x Where 0 < x < 2; Step 510: Add multiple porous carbon particles to a grinder and continue mixing and grinding; the porous carbon particles have multiple pores on their surface, which can absorb the expanded silicon particles; Step 520: Take out the ground material and put it into a vacuum concentrator to remove the alcohol solution, and obtain a mixture powder; Step 530: The mixed powder is placed in a sintering furnace for atmosphere sintering; during the sintering process, asphalt and polymer materials form a carbon layer on the outer surface of porous carbon particles, and multiple silicon particles and composite silicon particles are distributed in the carbon layer, forming the first particle as a whole, and multiple first particles are obtained in the furnace; the silicon particles and composite silicon particles are discontinuously distributed, attached to the surface of porous carbon particles or suspended in the carbon layer in an island-like form, and separated from the porous carbon particles; Step 540: Add multiple zinc oxide particles and multiple first particles to a rolling mixer and mix them so that the outer surface of the first particles is coated with a zinc oxide layer formed by the zinc oxide particles to obtain composite electrode particles; the zinc oxide particles are distributed in an island-like pattern.

2. The method for manufacturing composite electrode particles having composite silicon particles, a carbon layer, and zinc oxide coating as described in claim 1, characterized in that, The overall particle size of the composite electrode particles is 5 to 12 micrometers; the SiO x The range of x in the equation is: 0.1 < x < 0.

8.

3. The method for manufacturing composite electrode particles having composite silicon particles, a carbon layer, and zinc oxide coating as described in claim 1, characterized in that, In step 500, the grinding machine is a wet grinding machine, the grinding time is 4 to 6 hours, and the rotation speed is 2600 rpm to 3000 rpm.

4. The method for manufacturing composite electrode particles having composite silicon particles, a carbon layer, and zinc oxide coating as described in claim 1, characterized in that, The alcohol solution mentioned therein is isopropanol or ethanol.

5. The method for manufacturing composite electrode particles having composite silicon particles, a carbon layer, and zinc oxide coating as described in claim 1, characterized in that, The polymer material is selected from at least one of sodium dodecyl sulfate, polyvinylpyrrolidone, carboxymethyl cellulose, carboxyl long-chain polymers, or some phenolic resins.

6. The method for manufacturing composite electrode particles having composite silicon particles, a carbon layer, and zinc oxide coating as described in claim 1, characterized in that, Before grinding, the weight ratio of silicon particles: polymer materials: asphalt is 8~9:0.2~1:0.2~1.

7. The method for manufacturing composite electrode particles having composite silicon particles, a carbon layer, and zinc oxide coating as described in claim 1, characterized in that, The weight ratio of the solid, composed of silicon particles, polymer materials, and asphalt, to the alcohol solution is 4:

6.

8. The method for manufacturing composite electrode particles having composite silicon particles, a carbon layer, and zinc oxide coating as described in claim 1, characterized in that, After grinding in step 500, the particle size of the composite silicon particles is 10 to 30 nanometers, and the thickness of the silicon oxide layer is less than 3 nanometers.

9. The method for manufacturing composite electrode particles having composite silicon particles, a carbon layer, and zinc oxide coating as described in claim 1, characterized in that, In step 510, the grinding time is 0.5 to 2 hours and the rotation speed is 1800 rpm to 2200 rpm.

10. The method for manufacturing composite electrode particles having composite silicon particles, a carbon layer, and zinc oxide coating as described in claim 1, characterized in that, In step 510, the ratio of the total weight of porous carbon particles to the total weight of silicon particles is 8~9.5:0.5~2.

11. The method for manufacturing composite electrode particles having composite silicon particles, a carbon layer, and zinc oxide coating as described in claim 1, characterized in that, After grinding in step 510, the porous carbon particles have a particle size of 5 to 10 micrometers.

12. The method for manufacturing composite electrode particles having composite silicon particles, a carbon layer, and zinc oxide coating as described in claim 1, characterized in that, In step 530, the sintering temperature is 980℃~1100℃ and the sintering time is 6~8 hours.

13. The method for manufacturing composite electrode particles having composite silicon particles, a carbon layer, and zinc oxide coating as described in claim 1, characterized in that, The sintering atmosphere is argon or nitrogen atmosphere sintering.

14. The method for manufacturing composite electrode particles having composite silicon particles, a carbon layer, and zinc oxide coating as described in claim 1, characterized in that, In step 540, the mixer is a rolling mixer with a mixing time of 0.5 to 2 hours and a rotation speed of 200 rpm to 350 rpm; the mixer is filled with zirconium beads with a zirconium bead filling rate of 30% to 50% and a single zirconium bead particle size of 1.2 mm to 2 mm.

15. The method for manufacturing composite electrode particles having composite silicon particles, a carbon layer, and zinc oxide coating as described in claim 1, characterized in that, Also includes: Step 550: Place multiple composite electrode particles and multiple carbon nanotubes in a dry mixer and mix them to coat the composite electrode particles with carbon nanotubes, forming carbon nanotube-coated electrode particles. The carbon nanotubes are attached to the surface of the composite electrode particles in a "ball-like" manner to improve electronic conductivity.

16. The method for manufacturing composite electrode particles having composite silicon particles, a carbon layer, and zinc oxide coating as described in claim 15, characterized in that, The length of the carbon nanotubes is less than 5 micrometers.

17. The method for manufacturing composite electrode particles having composite silicon particles, a carbon layer, and zinc oxide coating as described in claim 15, characterized in that, In each carbon nanotube-coated electrode particle, the total weight of carbon nanotubes to the weight of the composite electrode particles is between 1:99 and 0.2:99.8.

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