METHOD FOR MANUFACTURING NCM POSITIVE ELECTRODE PARTICLES COATED WITH Ga-LLZO, LATP AND CNT

Abstract

A method for manufacturing NCM positive electrode particles coated with Ga-LLZO, LATP and CNT comprises the steps that a positive electrode slurry layer is coated on a positive electrode substrate, and the positive electrode slurry layer comprises positive electrode slurry containing a binding agent; the process comprises the following steps: taking a plurality of NCM large particles; uniformly mixing an LATP material and a Ga-LLZO material with the plurality of NCM large particles so as to form composite NCM large particles; carrying out aerobic sintering on the composite NCM large particles to obtain sintered powder; mixing the sintered powder with CNT (carbon nanotubes), so that the composite NCM large particles are coated with the CNT to form the positive electrode particles; wherein the CNT is a very good conductive material.

Description

Technical Field

[0001] The present invention relates to anode materials, and more particularly to a method for manufacturing NCM cathode particles coated with Ga-LLZO, LATP and CNT. Background Art

[0002] Batteries are mainly formed by placing positive and negative electrodes in an electrolyte. The positive electrode is made by mixing and dispersing a large number of positive electrode conductive units (positive electrode materials, such as lithium cobalt oxide) in a slurry. Generally speaking, the positive electrode conductive units must be mixed with the conductive slurry before they can be applied to the electrode sheet and assembled into a battery. Therefore, the numerous positive electrode conductive units (positive electrode materials) are connected to each other through the conductive slurry. Therefore, the conductive slurry must have conductive properties or conductivity to enable free electrons to migrate between different positive electrode conductive units without consuming too much energy due to internal resistance, thereby achieving the purpose of effective conduction. Therefore, when manufacturing the slurry, it is necessary to consider the use of specific conductive materials to adjust the conductivity of the slurry.

[0003] Generally, in order to increase conductivity, a plurality of positive electrode particles are filled in the positive electrode slurry, wherein the material of the positive electrode particles can be selected from NCM (lithium nickel cobalt manganese oxide), LMFP (lithium manganese iron phosphate), etc. or a mixture thereof, and the positive electrode particles are distributed in the positive electrode slurry.

[0004] In other patents of the applicant, in order to further increase the conductivity of the entire slurry, carbon nanotubes are added to the slurry to surround the positive electrode particles in the positive electrode material of the battery. The carbon nanotubes are then used to bridge different positive electrode conductive units, thereby reducing the internal resistance generated by electrons crossing the slurry to another positive electrode conductive unit, thereby improving the conductivity of the entire positive electrode.

[0005] The above-mentioned prior arts mainly increase the overall conductivity of the contents in the positive electrode slurry, thereby increasing the capacitance and conductivity of the entire positive electrode.

[0006] Based on the applicant's long experience in battery materials, the applicant hopes to propose a new design that can make the positive electrode of the current solid-state battery more conductive, thereby further improving the energy efficiency of the battery. Summary of the Invention

[0007] Therefore, the purpose of the present invention is to solve the above-mentioned problems in the prior art. The present invention proposes a method for manufacturing NCM positive electrode particles coated with Ga-LLZO, LATP and CNT, forming large NCM particles whose outer surfaces are coated with numerous Ga-LLZO and LATP fine particles. Because the ability of the LATP fine particles to accommodate and evenly distribute lithium ions is much higher than that of the large NCM particles, and the large NCM particles can be prevented from being corroded by the electrolyte, while extending the service life of the battery. In addition, multiple Ga-LLZO fine particles are attached to the surfaces of multiple large NCM particles. The Ga-LLZO fine particles have the ability to accommodate and evenly distribute lithium ions. Therefore, when lithium ions pass through the positive electrode, the path of the lithium ions can be dispersed through the guidance of the dispersed Ga-LLZO fine particles. Therefore, the design of the positive electrode of the present invention can provide a better path for lithium ions. The present invention further coats CNTs (carbon nanotubes) on the outside of the large NCM particles coated with Ga-LLZO and LATP fine particles. The role of CNTs is to form conductive bridges around the various Ga-LLZO and LATP fine particles, allowing electrons to conduct through the composite NCM large particles. The architecture of the present invention provides stability to the overall positive electrode slurry structure, thereby reducing the amount of cobalt used.

[0008] To achieve the above-mentioned purpose, the present invention proposes a method for manufacturing NCM positive electrode particles coated with Ga-LLZO, LATP and CNT, comprising: a positive electrode substrate, which is a carrier for carrying a positive electrode material; a positive electrode slurry layer coated on the positive electrode substrate, wherein the positive electrode slurry layer comprises: a positive electrode slurry containing a binder; a plurality of positive electrode particles, which account for 65 to 70 wt% of the positive electrode slurry; wherein the process of the positive electrode particles is as follows: Step 500: Take NCM (lithium nickel cobalt manganese oxide) material, wherein the NCM material is a plurality of NCM large particles, and the plurality of NCM large particles are all single crystal structures (single crystal); mixing LATP (Li1+xAlxTi2-x(PO4)3) material and Ga-LLZO (gallium-doped lithium lanthanum zirconium oxide) material with a plurality of the NCM large particles; wherein the Ga-LLZO material is a plurality of Ga-LLZO fine particles; and the LATP material is a plurality of LATP fine particles (step 500); step 510: simultaneously placing the NCM large particles, the Ga-LLZO fine particles, and the LATP fine particles into a three-dimensional mixer or a flat roller mixer and stirring them thoroughly to ensure that the three are evenly mixed. The whole is formed into a composite NCM large particle; Step 520: Then the composite NCM large particle is oxygen-sintered to obtain a sintered powder; basically, after sintering, the longitudinal dimension of the Ga-LLZO fine particle and the LATP fine particle becomes shorter, the lateral dimension becomes wider, and the total volume remains unchanged; after sintering, the Ga-LLZO fine particle is distributed in a convex arc shape on the NCM large particle, which is high in the middle and flat at both ends; a Ga-LLZO interphase layer is formed between the bottom of the Ga-LLZO fine particle and the NCM large particle; wherein the LATP fine particle is The NCM large particles are distributed in a convex arc shape, with a high middle and flat ends. A LATP interphase layer is formed between the bottom of the LATP fine particles and the NCM large particles. Step 530: The sintered powder and CNT are then placed in a planetary mixer or a drum mixer for mixing, so that the CNT covers the composite NCM large particles to form the positive electrode particles. CNT is a very good conductive material used to increase electronic conductivity, that is, to form a conductive framework around the various Ga-LLZO fine particles and the LATP fine particles. bridge, so that electrons are conducted on the composite NCM large particles; the CNTs are randomly distributed on the surface of the composite NCM large particles; after stirring in step 530, the composite NCM large particles with the CNTs coated on the outer surface can be formed, that is, the positive electrode particles are formed; the CNTs can form different levels of bridges on the composite NCM large particles, wherein the CNTs are short-chain CNTs with a length of less than 0.5 to 1 micron; the short-chain CNTs are used to bridge the Ga-LLZO fine particles and the NCM large particles, and bridge the LATP fine particles and the NCM large particles.

[0009] Furthermore, the total weight of the CNT accounts for less than 0.25% of the weight of a single large NCM particle.

[0010] Furthermore, the agitator is a wet agitator or a dry agitator.

[0011] Furthermore, before sintering, the lateral size of the Ga-LLZO fine particles is less than 100 nanometers; and the lateral size of the LATP fine particles is less than 50 nanometers.

[0012] Furthermore, after sintering, the NCM large particles have a size of 3 to 5 microns; the Ga-LLZO fine particles have a lateral size of 100 to 280 nanometers; and the LATP fine particles have a lateral size of 50 to 100 nanometers.

[0013] Furthermore, the total weight of the Ga-LLZO fine particles relative to the weight of the single NCM large particle is between 0.5 and 0.8 wt %; the total weight of the LATP fine particles relative to the weight of the single NCM large particle is between 0.1 and 0.3 wt %.

[0014] Furthermore, the rotation speed of the three-dimensional mixer or flat roller mixer is 50 to 100 rpm, and the stirring time is 8 to 12 hours. After stirring, the outer surface of the NCM large particles is covered with numerous Ga-LLZO fine particles and LATP fine particles, and the whole forms the composite NCM large particles.

[0015] Furthermore, in step 520, the sintering temperature is 550 to 650°C, the temperature is increased at 3 to 5°C / min, and the temperature is maintained at the highest temperature for 1 to 2 hours to obtain sintered powder.

[0016] Furthermore, the radial thickness of the Ga-LLZO interphase layer is between 2 and 10 nanometers; the Ga-LLZO interphase layer is formed by Ga-LLZO and cobalt oxide, which serves to provide a better guiding channel for ions; and

[0017] The radial thickness of the LATP interphase layer is between 2 and 10 nanometers. The LATP interphase layer is formed by LATP and cobalt oxide to provide protection and prevent the large NCM particles from being corroded by the electrolyte.

[0018] Furthermore, the planetary mixer or drum mixer has a stirring speed of 50 to 150 rpm and a stirring time of 3 to 6 hours.

[0019] The beneficial effects of the present invention are:

[0020] The present invention proposes a method for manufacturing NCM positive electrode particles coated with Ga-LLZO, LATP and CNT, forming large NCM particles whose outer surfaces are coated with numerous Ga-LLZO and LATP fine particles, thereby preventing the large NCM particles from being corroded by the electrolyte and extending the service life of the battery. In addition, multiple Ga-LLZO fine particles are attached to the surfaces of the multiple large NCM particles; the Ga-LLZO fine particles have the ability to accommodate and evenly flow lithium ions, allowing lithium ions to have a better path; and the architecture of the present invention can provide stability to the overall positive electrode slurry structure, thereby reducing the use of cobalt.

[0021] The features and advantages of the present invention may be further understood from the following description, which should be read with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Showing the manufacturing flow chart of the present invention;

[0023] Figure 2 A diagram showing the structure of the positive electrode particles of the present invention;

[0024] Figure 3 A structural diagram showing the positive electrode of the present invention;

[0025] Figure 4 A diagram showing the structure of the composite NCM large particles of the present invention;

[0026] Figure 5 Another structural diagram showing the composite NCM large particles of the present invention.

[0027] Description of Reference Numerals

[0028] 100, positive electrode;

[0029] 10. Positive electrode substrate;

[0030] 12. Positive electrode slurry layer;

[0031] 14. Cathode slurry;

[0032] 200, positive electrode particles;

[0033] 20. Composite NCM large particles;

[0034] 22. NCM large particles;

[0035] 24. Ga-LLZO fine particles;

[0036] 25. Ga-LLZO interphase layer;

[0037] 26. LATP fine particles;

[0038] 27. LATP interphase layer;

[0039] 30. CNT;

[0040] 32. Short-chain CNT. DETAILED DESCRIPTION

[0041] The structural composition of the present invention, as well as the effects and advantages it can produce, is described in detail below with reference to the drawings and a preferred embodiment of the present invention.

[0042] Please refer to Figures 1 to 5 As shown, the method for manufacturing NCM positive electrode particles coated with Ga-LLZO, LATP and CNT of the present invention comprises:

[0043] like Figure 3 As shown, a typical solid-state or quasi-solid-state battery positive electrode 100 includes:

[0044] A positive electrode substrate 10 is a carrier plate for supporting the material of the positive electrode 100;

[0045] A positive electrode slurry layer 12 is coated on the positive electrode substrate 10, wherein the positive electrode slurry layer 12 includes:

[0046] A positive electrode slurry containing a binder 14;

[0047] A plurality of positive electrode particles 200, which account for 65 to 70 wt% of the positive electrode slurry 14. The process of the positive electrode particles 200 (please refer to Figure 1 )as follows:

[0048] Step 500: Take NCM (nickel cobalt manganese oxide) material, wherein the NCM material is a plurality of large NCM particles 22 with a size of 3 to 5 microns and a single crystal structure. The large NCM particles 22 are irregular cubic in shape.

[0049] LATP(Li 1+x Al x Ti 2-x (PO4)3) materials and Ga-LLZO (such as Li 6.2 Ga 0.8 La3Zr2O 12 ), gallium-doped lithium lanthanum zirconium oxide) material is mixed with a plurality of the NCM large particles 22, wherein the Ga-LLZO material is a plurality of Ga-LLZO fine particles 24, and the lateral size of the Ga-LLZO fine particles 24 (i.e., the size along the spherical surface of the Ga-LLZO fine particles) is less than 100 nanometers; the LATP material is a plurality of LATP fine particles 26, and the lateral size of the LATP fine particles 26 (i.e., the size along the spherical surface of the LATP fine particles) is less than 50 nanometers.

[0050] The total weight ratio of the Ga-LLZO fine particles 24 to the weight of the single NCM large particle 22 is between 0.5 and 0.8 wt %. The total weight ratio of the LATP fine particles 26 to the weight of the single NCM large particle 22 is between 0.1 and 0.3 wt %.

[0051] Step 510: Place the above-mentioned NCM large particles 22, the Ga-LLZO fine particles 24 and the LATP fine particles 26 into a three-dimensional mixer or a flat roller mixer at the same time and stir them thoroughly so that the three are evenly mixed. The rotation speed of the three-dimensional mixer or the flat roller mixer is 50 to 100 rpm, and the stirring time is 8 to 12 hours. After stirring, the outer surface of the NCM large particle 22 is covered with a large number of Ga-LLZO fine particles 24 and LATP fine particles 26, and the whole forms a composite NCM large particle 20.

[0052] Step 520: The composite NCM large particles 20 are then subjected to oxygen sintering at a temperature of 550 to 650°C, with a temperature increase of 3 to 5°C / minute and a holding time of 1 to 2 hours at the highest temperature, to produce a sintered powder. After sintering, the Ga-LLZO fine particles 24 and the LATP fine particles 26 are substantially shortened in the longitudinal direction and widened in the transverse direction, while maintaining their overall volume.

[0053] After sintering, the Ga-LLZO fine particles 24 are distributed on the NCM large particles 22 in a convex arc shape, with a high middle and flat ends (e.g. Figure 4 A Ga-LLZO interphase layer 25 is formed between the bottom of the Ga-LLZO fine particle 24 and the large NCM particle 22. This Ga-LLZO interphase layer 25 is primarily composed of Ga-LLZO and cobalt oxides (where the cobalt primarily originates from the outer layer of the large NCM particle 22), providing a better ion guidance path. The radial thickness of the Ga-LLZO interphase layer 25 ranges from 2 to 10 nanometers.

[0054] The LATP fine particles 26 are distributed on the NCM large particles 22 in a convex arc shape, with a high middle and flat ends (e.g. Figure 5 A LATP interphase layer 27 is formed between the bottom of the LATP fine particle 26 and the large NCM particle. This LATP interphase layer 27 is primarily composed of LATP and cobalt oxides (where the cobalt primarily originates from the outer layer of the large NCM particle 22). Its primary function is to protect the large NCM particle 22 from electrolyte corrosion. The radial thickness of this LATP interphase layer 27 ranges from 2 to 10 nanometers.

[0055] Step 530: The sintered powder and CNT30 (carbon nanotube) dry powder are placed in a planetary mixer or a drum mixer for mixing, so that the CNT30 coats the composite NCM large particles 20 to form the positive electrode particles 200. The planetary mixer or drum mixer is stirred at a speed of 50 to 150 rpm for 3 to 6 hours.

[0056] The CNT 30 is a short-chain CNT 32 with a length between 0.5 and 1 micrometer. The total weight of the CNT 30 accounts for less than 0.25% of the weight of a single large NCM particle 22 .

[0057] The CNT 30 can form different levels of cross-connections on the composite NCM large particle 20. When more CNT 30 is added, it will contribute to the conductivity of the entire composite NCM large particle 20. Figure 2 As shown, the short-chain CNT 32 is used to bridge the Ga-LLZO fine particles 24 and the NCM large particles 22, and bridge the LATP fine particles 26 and the NCM large particles 22; CNT 30 is a very good conductive material, and when it is attached to the composite NCM large particles 20, it forms a shape like a ball of yarn.

[0058] The CNTs 30 are used to increase electronic conductivity by forming conductive bridges around the various Ga-LLZO fine particles 24 and the LATP fine particles 26, allowing electrons to conduct across the composite NCM large particles 20. The CNTs 30 are randomly distributed across the surface of the composite NCM large particles 20. Because the CNTs 30 have extremely high conductivity, electrons can pass through the CNTs 30 and conduct between the various Ga-LLZO fine particles 24 and the LATP fine particles 26 and the NCM large particles 22, thereby increasing the overall conductivity of the entire positive electrode 100.

[0059] The agitator in the present invention is divided into two types, one is a wet agitator (such as a planetary agitator) and the other is a dry agitator (such as a three-dimensional mixer). The wet agitator has a better effect, but needs to be dried to remove moisture.

[0060] After stirring in step 530, the composite NCM large particles 20 are formed, with the CNT 30 coated on the outer surface, forming the positive electrode particles 200. After sintering and stirring, the NCM large particles 22 have a size of 3 to 5 microns; the Ga-LLZO fine particles 24 have a lateral size (i.e., the size along the spherical surface) between 100 and 280 nanometers; and the LATP fine particles 26 have a lateral size (i.e., the size along the spherical surface) between 50 and 100 nanometers.

[0061] The advantage of using CNT30 in this invention is that lithium ions can be easily stabilized between the CNT30. Therefore, the cathode slurry of this invention can stabilize a large number of lithium ions, thereby improving the overall lithium ion conductivity. Electrons can also be easily fixed between the short-chain CNT32, thereby improving the overall lithium ion conductivity. Furthermore, this extremely high ionic conductivity facilitates rapid charging and discharging of the entire battery, and can also reduce cobalt usage, thereby lowering overall production costs.

[0062] The advantage of the present invention is that it forms large NCM particles whose outer surfaces are coated with numerous Ga-LLZO and LATP fine particles. This is because the LATP fine particles have a much higher capacity to accommodate and evenly distribute lithium ions than the large NCM particles, and can prevent the large NCM particles from being corroded by the electrolyte, while also extending the battery's service life. Furthermore, multiple Ga-LLZO fine particles are attached to the surfaces of the multiple large NCM particles. The Ga-LLZO fine particles have the ability to accommodate and evenly distribute lithium ions. Therefore, when lithium ions pass through the positive electrode, they can be guided by the dispersed Ga-LLZO fine particles, thereby dispersing the lithium ion pathway. Therefore, the design of the positive electrode of the present invention can provide a better pathway for lithium ions. The present invention further coats the outer surface of the large NCM particles coated with Ga-LLZO and LATP fine particles with CNT30. The function of CNT30 is to form conductive bridges around the various different Ga-LLZO fine particles and LATP fine particles, allowing electrons to be conducted on the composite large NCM particles. The architecture of the present invention can provide stability to the overall positive electrode slurry structure, thereby reducing the amount of cobalt used.

[0063] The above detailed description is a specific description of a feasible embodiment of the present invention, but the embodiment is not intended to limit the patent scope of the present invention. Any equivalent implementation or modification that does not depart from the present invention should be included in the patent scope of the present invention.

Claims

1. A method for producing NCM cathode particles coated with Ga-LLZO, LATP and CNT, characterized in that: include: A positive electrode substrate is a carrier plate used to support a positive electrode material; A positive electrode slurry layer is coated on the positive electrode substrate, wherein the positive electrode slurry layer comprises: A positive electrode slurry containing a binder; A plurality of positive electrode particles, each of which accounts for 65 to 70 wt% of the positive electrode slurry, wherein the process of the positive electrode particles is as follows: Step 500: Obtain an NCM material, wherein the NCM material is a plurality of large NCM particles, and the plurality of large NCM particles are all single crystal structures; Mixing LATP material and Ga-LLZO material with a plurality of the NCM large particles; wherein the Ga-LLZO material is a plurality of Ga-LLZO fine particles; and the LATP material is a plurality of LATP fine particles; Step 510: placing the NCM large particles, the Ga-LLZO fine particles, and the LATP fine particles simultaneously into a three-dimensional mixer or a flat roller mixer and stirring them sufficiently to uniformly mix the three particles to form composite NCM large particles; Step 520: oxygen-sintering the composite NCM large particles to obtain sintered powder. After sintering, the Ga-LLZO fine particles and the LATP fine particles have a shorter longitudinal dimension and a wider transverse dimension, while the total volume remains unchanged. After sintering, the Ga-LLZO fine particles are distributed on the NCM large particles in a convex arc shape, with a high middle and flat ends; a Ga-LLZO interphase layer is formed between the bottom of the Ga-LLZO fine particles and the NCM large particles; The LATP fine particles are distributed on the NCM large particles in a convex arc shape, with a high middle and flat ends; a LATP interphase layer is formed between the bottom of the LATP fine particles and the NCM large particles; Step 530: The sintered powder and CNT dry powder are placed in a planetary mixer or a drum mixer for mixing, so that the CNTs cover the composite NCM large particles to form the positive electrode particles. The CNTs are a good conductive material and are used to increase electronic conductivity. Specifically, conductive bridges are formed around the various Ga-LLZO fine particles and the LATP fine particles, allowing electrons to be conducted on the composite NCM large particles. The CNTs are randomly distributed on the surface of the composite NCM large particles. After the stirring in step 530 , the composite NCM large particles with the CNT coated on the outer surface are formed, that is, the positive electrode particles are formed; The CNT is used to form different levels of cross-linking on the composite NCM large particles. The CNT is a short-chain CNT with a length of less than 0.5 to 1 micron; the short-chain CNT is used to bridge the Ga-LLZO fine particles and the NCM large particles, and bridge the LATP fine particles and the NCM large particles.

2. The method for producing NCM positive electrode particles coated with Ga-LLZO, LATP and CNT according to claim 1, characterized in that: The proportion of the total weight of the CNT to the weight of a single NCM large particle is less than 0.25%.

3. The method for producing NCM positive electrode particles coated with Ga-LLZO, LATP and CNT according to claim 1, characterized in that: The agitator is a wet agitator or a dry agitator.

4. The method for producing NCM positive electrode particles coated with Ga-LLZO, LATP and CNT according to claim 1, characterized in that Before sintering, the lateral size of the Ga-LLZO fine particles is less than 100 nanometers; the lateral size of the LATP fine particles is less than 50 nanometers.

5. The method for producing NCM positive electrode particles coated with Ga-LLZO, LATP and CNT according to claim 1, characterized in that: After sintering, the NCM large particles have a size of 3 to 5 microns; the Ga-LLZO fine particles have a lateral size of 100 to 280 nanometers; and the LATP fine particles have a lateral size of 50 to 100 nanometers.

6. The method for producing NCM cathode particles coated with Ga-LLZO, LATP and CNT according to claim 1, wherein: The total weight ratio of the Ga-LLZO fine particles to the weight of the single NCM large particle is between 0.5 and 0.8 wt %. The total weight ratio of the LATP fine particles to the weight of the single NCM large particle is between 0.1 and 0.3 wt %.

7. The method for producing NCM positive electrode particles coated with Ga-LLZO, LATP and CNT according to claim 1, characterized in that: The rotation speed of the three-dimensional mixer or flat roller mixer is 50 to 100 rpm, and the stirring time is 8 to 12 hours. After stirring, the outer surface of the NCM large particle is covered with numerous Ga-LLZO fine particles and LATP fine particles, and the whole forms the composite NCM large particle.

8. The method for producing NCM cathode particles coated with Ga-LLZO, LATP and CNT according to claim 1, wherein: In step 520 , the sintering temperature is 550° C. to 650° C., and the temperature is increased at a rate of 3° C. to 5° C. / min. The temperature is maintained at the highest temperature for 1 to 2 hours to obtain sintered powder.

9. The method for producing NCM cathode particles coated with Ga-LLZO, LATP and CNT according to claim 1, wherein: The radial thickness of the Ga-LLZO interphase layer is between 2 and 10 nanometers. The Ga-LLZO interphase layer is formed of Ga-LLZO and cobalt oxide, and its function is to provide a better guiding channel for ions; and The radial thickness of the LATP interphase layer is between 2 and 10 nanometers. The LATP interphase layer is formed by LATP and cobalt oxide to provide protection and prevent the large NCM particles from being corroded by the electrolyte.

10. The method for producing NCM cathode particles coated with Ga-LLZO, LATP and CNT according to claim 1, wherein: The planetary mixer or drum mixer has a stirring speed of 50 to 150 rpm and a stirring time of 3 to 6 hours.

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