Method for producing NCM cathode particles coated with LLZO and a glass phase in a sintering process

Abstract

To provide a method for producing NCM positive electrode particles coated with LLZO and a glass phase by a sintering process.SOLUTION: A method for preparing a cathode material for a lithium-ion battery, comprising the steps of: A step A of simultaneously introducing a plurality of NCM (lithium nickel manganese cobalt oxide) large particles and a glass phase material into a first stirrer and uniformly mixing them, wherein the glass phase material is an amorphous solid electrolyte or a non-oxide solid electrolyte with a lithium ion conductivity of more than 10-5S / cm; a step B of sintering the mixed NCM large particles and the glass phase material in an oxygen-containing atmosphere; a step C of introducing a plurality of LLZO microparticles and the NCM particles with the glass phase into a second stirrer and mixing them to form a plurality of composite NCM particles; a step D of sintering the composite NCM particles in an oxygen-containing atmosphere to form a plurality of sintered powders; and a step E of mixing a plurality of the sintered powders with a plurality of carbon nanotubes and a plurality of nanoscale amorphous carbon to form a carbon material mixture.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a cathode material, and more particularly to a method for producing NCM cathode particles coated with LLZO and a glass phase by a sintering process. [Background technology]

[0002] A battery is primarily composed of a positive electrode and a negative electrode placed in an electrolyte. The positive electrode is made by mixing and stirring many positive electrode conductive units (positive electrode materials such as lithium cobalt oxide) and dispersing them in a slurry. Typically, the positive electrode conductive units are first mixed and stirred with the conductive slurry before being applied to an electrode sheet and assembled into a battery. Since the positive electrode conductive units are connected to each other via the conductive slurry, the conductive slurry has conductive properties, allowing free electrons to migrate between different positive electrode conductive units and eliminating the need for excessive energy consumption due to internal resistance, thereby achieving the goal of efficient conductivity. Therefore, to adjust the conductivity of the slurry, it is necessary to manufacture the slurry using specific conductive materials. Summary of the Invention [Problem to be solved by the invention]

[0003] To improve electrical conductivity, the cathode slurry is filled with a plurality of cathode particles, the material of which is selected from lithium nickel manganese cobalt oxide (NCM), lithium manganese iron phosphate (LMFP), or a mixture thereof, and the cathode particles are dispersed in the cathode slurry. However, conventional cathode particles are prone to side reactions at their interfaces, shortening the service life of the cathode and reducing the overall efficiency of the battery due to their low electronic conductivity.

[0004] The present invention has been made in view of the above circumstances, and its object is to provide a method for producing NCM positive electrode particles coated with LLZO and a glass phase by a sintering process.

[0005] Therefore, the present inventors believed that the above drawbacks could be improved, and as a result of extensive research, they came up with the proposal of the present invention, which effectively improves the above problems through rational design. [Means for solving the problem]

[0006] To address the above-mentioned problems, one embodiment of the present invention provides a method for producing NCM positive electrode particles coated with LLZO and a glass phase by a sintering process. The outer surfaces of the NCM large particles are coated with a glass phase, which prevents the NCM large particles from directly contacting the electrolyte, suppressing interfacial side reactions and reducing the interfacial resistance when lithium ions enter and exit the NCM large particles. This improves the charge / discharge performance, accommodates volume changes during charge / discharge, improves the mechanical properties of the powder, and reduces fracture. The present invention coats the NCM large particles with a plurality of LLZO fine particles, which have the ability to accommodate and uniformly guide lithium ions. As lithium ions pass through the positive electrode, the LLZO fine particles guide them, dispersing the lithium ion pathways, providing more suitable pathways for the lithium ions. The present invention further coats the outer surface of the NCM large particle that covers the LLZO fine particles with multiple carbon nanotubes and nanoscale amorphous carbon, allowing electrons to be conducted through the composite NCM particle, and the nanoscale amorphous carbon fills the spaces between the multiple carbon nanotubes to form a complete electron conduction path, thereby providing stability to the entire cathode structure and reducing the amount of cobalt used.

[0007] Other features of the present invention will become apparent from the description of this specification and the accompanying drawings. [Brief explanation of the drawings]

[0008] [Figure 1]1 is a flowchart illustrating a method for manufacturing positive electrode particles according to an embodiment of the present invention. [Figure 2] 1 is a diagram showing a configuration of a positive electrode particle according to an embodiment of the present invention. [Figure 3] FIG. 1 is a structural diagram showing a positive electrode according to an embodiment of the present invention. [Figure 4] 1 is a structural diagram showing a composite NCM particle according to one embodiment of the present invention. [Figure 5] 1 is a structural diagram showing a composite NCM particle and short-chain carbon nanotubes according to an embodiment of the present invention. [Figure 6] 1 is a diagram showing a configuration of a positive electrode particle covering a carbon nanotube according to an embodiment of the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0009] The following describes in detail the embodiments of the present invention, but the present invention is not limited to these, and various modifications are possible within the scope of the description, and embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention.

[0010] First, a specific embodiment of a method for producing NCM positive electrode particles coated with LLZO and a glass phase according to the present invention by a sintering process will be described with reference to FIGS. 1 to 6. FIG.

[0011] The NCM positive electrode particles of the present invention are primarily used in a positive electrode 100 of a typical solid-state or solid-state battery. The positive electrode 100 includes a positive electrode substrate 10 and a positive electrode slurry layer 12 applied to the positive electrode substrate 10. The positive electrode slurry layer 12 includes a positive electrode slurry 14 containing a binder and a plurality of positive electrode particles 200 distributed within the positive electrode slurry 14 (see FIG. 3). The binder may be PVDF (polyvinylidene difluoride), PEO (polyethylene oxide), or the like. The plurality of positive electrode particles 200 occupy 80 wt% to 98 wt% of the positive electrode slurry layer 12.

[0012] The LLZO and glass phase-coated NCM positive electrode particles of the present invention are the positive electrode particles 200, respectively, and the manufacturing method thereof (see FIG. 1) includes the following steps.

[0013] <Process 500> An NCM (lithium nickel manganese cobalt oxide) material is prepared. The NCM material is composed of a plurality of NCM large particles 22. NCM is a ternary oxide. Each of the NCM large particles 22 has a size ranging from 3 μm to 5 μm and a single crystal structure. Each of the NCM large particles 22 has an irregular cubic shape. The plurality of NCM large particles 22 and the glass phase material are simultaneously placed in a first agitator and thoroughly agitated to uniformly mix the plurality of NCM large particles 22 and the glass phase material. The rotation speed of the first agitator is in the range of 20 rpm to 500 rpm, and the agitation time is in the range of 2 hours to 12 hours. The first mixer may be a dry mixer (for example, a three-dimensional mixer or a flat roller mixer) or a wet mixer (for example, a DC blade mixer), and anhydrous alcohol or isopropanol solvent is added to the wet mixer.

[0014] The glass phase material has a lithium ion conductivity of 10 -5 The glass phase material is composed of an amorphous oxide or non-oxide solid electrolyte having a viscosity of greater than 1000 s / cm, and the glass phase material is an oxide of lithium and an element of groups IIIA, IVA, or VA (e.g., LiO-RO xwhere R is at least one element of boron (B), aluminum (Al), silicon (Si), germanium (Ge), phosphorus (P), and arsenic (As), and x=1 to 3), or at least one element of an amorphous oxide-based solid electrolyte (for example, an amorphous perovskite-based solid electrolyte (Li-La-Ti-O, LLTO), a garnet-based solid electrolyte (Li-La-Zr-O, LLZO), or a lithium phosphorus oxynitride (LiPON)).

[0015] <Process 510> After stirring, the NCM large particles 22 and the glass phase material are sintered in an oxygen atmosphere to form NCM particles 250 having a glass phase. The sintering temperature is between 250°C and 650°C, the heating rate is between 1.5°C / min and 5°C / min, and the maximum temperature holding time is between 0.5 hours and 4 hours. After sintering, each of the NCM particles 250 having a glass phase contains a corresponding NCM large particle 22, and some or all of the surfaces of the NCM large particle 22 are covered with a glass phase 25 formed from the glass phase material. The thickness of the glass phase 25 is between 5 nm and 100 nm.

[0016] The glass phase 25 can prevent direct contact between the NCM large particles 22 and the electrolyte, suppressing side reactions at the interface, and simultaneously reducing the interface resistance when lithium ions enter and exit the NCM large particles 22, improving the charge-discharge performance. The glass phase 25 can accommodate the volume that changes during charge and discharge, improving the mechanical properties of the powder and reducing fracture.

[0017] <Process 520> The LLZO material is mixed with a plurality of NCM particles 250 having the glass phase to form a plurality of composite NCM particles 20. The LLZO material is composed of a plurality of LLZO particles 24, each of which is lithium lanthanum zirconium oxide (Li7La3Zr2O 12, LLZO), or lithium lanthanum zirconium oxide doped with at least one metal element (e.g., Li 6.2 Ga 0.8 La3Zr2O 12 (This may be a gallium (Ga)-doped lithium lanthanum zirconium oxygen compound, or an aluminum (Al)-doped or barium (Ba)-doped lithium lanthanum zirconium oxygen compound.) The size of each of the NCM large particles 22 is larger than the size of each of the LLZO microparticles 24. The maximum radial size of each of the LLZO microparticles 24 is less than 40 nm.

[0018] The NCM particles 250 having a glass phase and the plurality of LLZO microparticles 24 are simultaneously placed in a second agitator (e.g., a three-dimensional agitator or a flat roller agitator) and thoroughly agitated to uniformly mix. The rotation speed of the second agitator is in the range of 20 rpm to 500 rpm, and the agitation time is in the range of 2 hours to 12 hours. After agitation, each of the LLZO microparticles 24 is distributed within the glass phase 25 of the corresponding NCM particle 250 having a glass phase or on the surface of the glass phase 25, and each of the NCM particles 250 having a glass phase and the corresponding LLZO microparticles 24 form a corresponding composite NCM particle 20 (see FIG. 4).

[0019] Preferably, each of the LLZO particles 24 is composed of at least one element selected from Ga-LLZO (Ga-doped LLZO, gallium-doped lithium lanthanum zirconium oxide), Cu-LLZO (Cu-doped LLZO, copper-doped lithium lanthanum zirconium oxide), Ta-LLZO (Ta-doped LLZO, tantalum-doped lithium lanthanum zirconium oxide), Sr-LLZO (Sr-doped LLZO, strontium-doped lithium lanthanum zirconium oxide), and Al-LLZO (Al-doped LLZO, aluminum-doped lithium lanthanum zirconium oxide).

[0020] Preferably, each of the LLZO particles 24 is Cua ,X b -LLZO, a ,X b LLZO is a lithium lanthanum zirconium oxide doped with copper and an element X, where X is selected from gallium (Ga), tantalum (Ta), strontium (Sr), barium (Ba), and aluminum (Al), and a > 0 and b > 0. Preferably, a + b = 0.25 to 0.8, and a > 0.1. Although the technique of doping LLZO with copper is very difficult, it further stabilizes the overall structure, smooths the lithium ion channels, improves the sintering rate, and significantly reduces manufacturing costs. Furthermore, when the LLZO particles 24 are exposed to air, the formation of lithium carbonate (Li2CO3) is reduced, i.e., the surface stability of the entire material is improved during sintering.

[0021] In each of the composite NCM particles 20, the ratio of the total weight of the corresponding plurality of LLZO microparticles 24 to the weight of the corresponding NCM particle 250 having the glass phase is in the range of 0.2% to 2%.

[0022] <Process 530> A plurality of the composite NCM particles 20 are sintered in an oxygen atmosphere to form a plurality of sintered powders. The sintering temperature is between 550 and 650°C, the heating rate is between 1.5 and 5°C / min, and the maximum temperature holding time is between 0.5 and 2 hours. The sintering process eliminates the interfacial resistance between the LLZO particles 24 and the NCM large particles 22 during lithium ion transport. Essentially, the LLZO particles 24 increase in lateral size (i.e., the size along the spherical surface of the corresponding NCM large particle 22) after sintering, while the longitudinal size along the radial direction of the NCM large particle 20 (i.e., the size perpendicular to the lateral direction) decreases, while the total volume remains unchanged. After sintering, each of the LLZO particles 24 adheres to the corresponding NCM particle 250 having the glass phase.

[0023] Next, a carbon material mixture is performed with a plurality of the sintered powders, a plurality of carbon nanotubes (CNTs) 30, and a plurality of nanoscale amorphous carbons 35 to form a plurality of carbon material-coated positive electrode particles 300. There are two methods for mixing the carbon material, which will be described below.

[0024] <The first method of mixing the carbon material is referred to as step 540A> The sintered powder, the carbon nanotubes 30, and the nanoscale amorphous carbon 35 are simultaneously mixed in a dry mixer (e.g., a planetary mixer or a drum mixer) to form the carbon material-coated positive electrode particles 300. Each of the carbon material-coated positive electrode particles 300 includes a corresponding composite NCM particle 20, and the corresponding carbon nanotubes 30 and nanoscale amorphous carbon 35 coat the exterior of the corresponding composite NCM particle 20 (see FIG. 1). The dry mixer has a stirring rotation speed ranging from 50 rpm to 500 rpm, and a stirring time ranging from 2 hours to 8 hours.

[0025] Preferably, the plurality of nanoscale amorphous carbons 35 are amorphous carbons of super P conductive additive. The size of each of the nanoscale amorphous carbons 35 ranges from 20 nm to 100 nm. In each of the carbon material-coated positive electrode particles 300, each of the nanoscale amorphous carbons 35 is mainly located in gaps formed by the intersection of the corresponding plurality of carbon nanotubes 30 (see FIG. 2). In each of the carbon material-coated positive electrode particles 300, the ratio of the total weight of the corresponding plurality of nanoscale amorphous carbons 35 to the weight of the corresponding composite NCM particle 20 ranges from 0.1% to 2%.

[0026] <The second method of mixing the carbon material is referred to as step 540B> First, the carbon nanotubes 30 and the sintered powders 40 are mixed together a first time, and then the nanoscale amorphous carbons 35 are added and mixed a second time to form the carbon-coated positive electrode particles 300. Each of the carbon-coated positive electrode particles 300 includes a corresponding composite NCM particle 20, and the corresponding carbon nanotubes 30 and nanoscale amorphous carbons 35 coat the exterior of the corresponding composite NCM particle 20. The first and second mixing processes are performed by dry ball mill mixing or wet ball mill mixing.

[0027] When the first and second mixing steps are dry ball mill mixing, the carbon nanotubes 30 and the sintered powders are first loaded into a dry ball mill, and the first mixing step is performed using a ball mill. Then, the nanoscale amorphous carbons 35 are added to the dry ball mill, and the second mixing step is performed using a ball mill to form the carbon material-coated positive electrode particles 300. In the first and second mixing steps, the rotation speed of the dry ball mill is in the range of 50 rpm to 1000 rpm, the mixing time is in the range of 20 minutes to 12 hours, and the ball milling is performed at room temperature of 50°C.

[0028] When the first and second mixing steps are wet ball mill mixing, the carbon nanotubes 30 are first dispersed in a dispersant and then introduced into a wet ball mill together with the sintered powders. The first mixing step is performed using the wet ball mill. Then, the nanoscale amorphous carbon particles 35 are added to the wet ball mill and the second mixing step is performed using the wet ball mill to form the positive electrode particles 300 that coat the carbon material. During the first and second mixing steps, the rotation speed of the wet ball mill is between 50 rpm and 500 rpm, and the mixing time is between 20 minutes and 12 hours. The dispersant is selected from polar and non-polar non-aqueous organic solvents.

[0029] <Process 540B> Using any one of the ball mill methods described above, a plurality of the carbon nanotubes 30 and a plurality of the sintered powders are mixed, and then a plurality of the nanoscale amorphous carbons 35 are added and mixed to form a plurality of positive electrode particles 300 coated with the carbon material.

[0030] Therefore, the present invention achieves the carbon material mixing by the above-mentioned step 540A or step 540B.

[0031] The carbon nanotubes 30 include a plurality of short-chain carbon nanotubes 32 and a plurality of long-chain carbon nanotubes 34, each of which has a length ranging from 0.5 μm to 1 μm, and each of which has a length ranging from 3 μm to 8 μm. In each of the carbon material-coated positive electrode particles 300, the ratio of the total weight of the corresponding carbon nanotubes 30 to the weight of the corresponding composite NCM particle 20 is between 0.1% and 2%.

[0032] The carbon nanotubes 30 can form bridges with different numbers of layers on the composite NCM particles 20. The more carbon nanotubes 30 added, the higher the conductivity of the composite NCM particles 20. As shown in Figures 5 and 6, each of the short-chain carbon nanotubes 32 is used to bridge the corresponding LLZO microparticles 24 and the NCM large particles 22. Each of the long-chain carbon nanotubes 34 is used to coat the corresponding composite NCM particle 20. The carbon nanotubes 30 are very conductive materials, and when attached to the corresponding composite NCM particle 20, they form a fuzzball-like morphology (see Figure 2).

[0033] The carbon nanotubes 30 are used to increase the electronic conductivity. That is, they form conductive bridges around the various different LLZO microparticles 24, allowing electrons to be conducted in each of the composite NCM particles 20. The carbon nanotubes 30 are randomly distributed on the surface of the corresponding composite NCM particle 20. Because carbon nanotubes have extremely high electrical conductivity, the carbon nanotubes 30 allow electrons to be conducted between the different LLZO microparticles 24 and the NCM large particles 22, thereby increasing the electrical conductivity of the entire positive electrode 100.

[0034] The plurality of nanoscale amorphous carbons 35 and the plurality of carbon nanotubes 30 act as conductive additives. Each of the nanoscale amorphous carbons 35 has a particle shape, and each of the carbon nanotubes 30 has an elongated shape. Gaps are formed between the plurality of carbon nanotubes 30 that are intertwined vertically and horizontally on the composite NCM particle 20. Because current does not conduct through these gaps, the corresponding nanoscale amorphous carbons 35 are added to these gaps, and the bridging of the nanoscale amorphous carbons 35 allows charge to be conducted between different carbon nanotubes 30, further improving current transmission efficiency.

[0035] In each of the positive electrode particles 300 coated with the carbon material, the ratio of the total weight of the corresponding plurality of carbon nanotubes 30 and the corresponding plurality of nanoscale amorphous carbons 35 to the weight of the corresponding composite NCM particle 20 is (0.09~3):100.

[0036] In each of the carbon material-coated positive electrode particles 300, the weight ratio of the corresponding plurality of carbon nanotubes 30, the corresponding plurality of nanoscale amorphous carbons 35, and the corresponding composite NCM particles 20 is 0.5:1:100.

[0037] After sintering, the size of each of the NCM large particles 22 ranges between 3 μm and 5 μm, the lateral size of each of the LLZO fine particles 24 ranges between 50 nm and 300 nm, and the size of each of the nanoscale amorphous carbon 35 ranges between 20 nm and 100 nm.

[0038] The advantage of using carbon nanotubes in the present invention is that lithium ions are easily stabilized between the carbon nanotubes 30, resulting in a solid and extremely abundant lithium ion cathode slurry of the present invention, and thus increased overall lithium ion conductivity. Furthermore, electrons are easily fixed between the short-chain carbon nanotubes 32, increasing overall lithium ion conductivity. Furthermore, the extremely high ion conductivity contributes to high-speed charging and discharging of the entire battery, further reducing the amount of cobalt used, and lowering overall manufacturing costs.

[0039] The above description is for the purpose of explaining the present invention, and should not be construed as limiting the invention described in the claims or narrowing its scope. Furthermore, the configuration of each part of the present invention is not limited to the above embodiment, and various modifications are possible within the technical scope described in the claims. [Explanation of symbols]

[0040] 10 Positive substrate 12 Positive electrode slurry layer 14 Positive electrode slurry 20 Composite NCM particles 22 NCM large particles 24 LLZO fine particles 25 Glass phase 30 Carbon nanotubes 32 Short-chain carbon nanotubes 34 Long-chain carbon nanotubes 35 Nanoscale amorphous carbon 100 positive electrode 200 positive particles 250 NCM particles with glass phase 300 Carbon nanotube coated cathode particles

Claims

1. A method for producing NCM positive electrode particles coated with LLZO and a glass phase by a sintering process, the NCM positive electrode particles being used in a positive electrode of a solid-state or solid-state battery, An NCM (lithium nickel manganese cobalt oxide) material is prepared, the NCM material being composed of a plurality of NCM large particles, each of which has an irregular cubic shape, and the plurality of NCM large particles are simultaneously introduced into a first stirrer together with a glass phase material and thoroughly stirred to homogeneously mix the plurality of NCM large particles and the glass phase material, and the glass phase material has a lithium ion conductivity of 10 -5 Step A is an amorphous oxide or non-oxide solid electrolyte having a conductivity greater than S / cm; a step B of sintering the plurality of NCM large particles and the glass phase material after stirring in an oxygen atmosphere to form a plurality of NCM particles having a glass phase, each of the NCM particles having a glass phase after sintering includes a corresponding NCM large particle, and some or all of the surfaces of the NCM large particle are covered with a glass phase formed of the glass phase material, the glass phase preventing the corresponding NCM large particle from directly contacting the electrolyte and suppressing interfacial side reactions, while also reducing the interfacial resistance when lithium ions enter and exit the NCM large particle; a step C of mixing an LLZO material with a plurality of NCM particles having the glass phase to form a plurality of composite NCM particles, the LLZO material being composed of a plurality of LLZO microparticles, the plurality of NCM particles having the glass phase and the plurality of LLZO microparticles being simultaneously introduced into a second agitator and sufficiently agitated to be uniformly mixed, after agitation each of the LLZO microparticles being distributed within the glass phase or on the surface of the glass phase of the corresponding NCM particle having the glass phase, and each of the NCM particles having the glass phase and the corresponding LLZO microparticles forming corresponding composite NCM particles; and step D, in which a plurality of the composite NCM particles are sintered in an oxygen atmosphere to form a plurality of sintered powders, and the sintering in the oxygen atmosphere eliminates the interfacial resistance between each of the LLZO fine particles and the corresponding NCM large particles during lithium ion transmission.

2. the size of each of the NCM large particles ranges between 3 μm and 5 μm and is a single crystal; the thickness of the glass phase ranges between 5 nm and 100 nm; 2. A method for manufacturing NCM positive electrode particles coated with LLZO and a glass phase by a sintering process, as described in claim 1, characterized in that in step C, the maximum radial size of each of the LLZO fine particles is less than 40 nm.

3. 2. The method for preparing NCM positive electrode particles coated with LLZO and a glass phase by a sintering process according to claim 1, wherein in step A, the first agitator is selected from a three-dimensional agitator, a flat roller agitator, or a DC blade agitator, and an anhydrous alcohol or isopropanol solvent is added to the DC blade agitator.

4. 2. The method for manufacturing NCM positive electrode particles coated with LLZO and a glass phase by a sintering process according to claim 1, wherein the amorphous oxide or non-oxide solid electrolyte is at least one element selected from the group consisting of oxides of lithium and elements of groups IIIA, IVA, and VA, amorphous oxide-based solid electrolytes, amorphous perovskite-based solid electrolytes, garnet-based solid electrolytes, and lithium-phosphorus-oxygen-nitride.

5. 2. The method for producing NCM positive electrode particles coated with LLZO and a glass phase by a sintering process according to claim 1, wherein the amorphous oxide or non-oxide solid electrolyte contains at least one of the following elements (A), (B), (C), and (D): (A) Li 2 O-RO x (wherein R is at least one element selected from boron (B), aluminum (Al), silicon (Si), germanium (Ge), phosphorus (P), and arsenic (As), and x=1 to 3). (B) LLTO (Li-La-Ti-O), (C)LLZO (He) 7 The 3 Zr 2 Oh 12 ), (D) LiPON (lithium phosphorus oxynitride).

6. 2. The method for producing NCM positive electrode particles coated with LLZO and a glass phase by a sintering process according to claim 1, wherein in step A, the sintering temperature is in the range of 250°C to 650°C, the heating rate is in the range of 1.5 to 5°C / min, and the maximum temperature holding time is in the range of 0.5 to 4 hours.

7. 2. The method for producing NCM positive electrode particles coated with LLZO and a glass phase by a sintering process according to claim 1, wherein each of the LLZO particles 24 is composed of at least one element selected from the group consisting of Ga-LLZO (Ga-doped LLZO, gallium-doped lithium lanthanum zirconium oxide), Cu-LLZO (Cu-doped LLZO, copper-doped lithium lanthanum zirconium oxide), Ta-LLZO (Ta-doped LLZO, tantalum-doped lithium lanthanum zirconium oxide), Sr-LLZO (Sr-doped LLZO, strontium-doped lithium lanthanum zirconium oxide), and Al-LLZO (Al-doped LLZO, aluminum-doped lithium lanthanum zirconium oxide).

8. Each of the LLZO particles is Cu a ,X b -LLZO, and a ,X b -LLZO is lithium lanthanum zirconium oxide doped with copper and element X, where X is selected from Ga (gallium), Ta (tantalum), Sr (strontium), Ba (barium), and Al (aluminum), and a+b=0.25-0.8, and a>0.1; a ,X b The LLZO-LLZO structure is more stable, the lithium ion channels are smoother, the sintering speed is improved, and the manufacturing cost is very low. When the LLZO particles are exposed to air, they turn into lithium carbonate (Li 2 CO 3 2. The method for producing NCM positive electrode particles coated with LLZO and glass phases by a sintering process according to claim 1, characterized in that the formation of LLZO and glass phases is reduced, i.e., the stability of the surface of the entire material during sintering is increased.

9. 2. The method for manufacturing NCM positive electrode particles coated with LLZO and a glass phase by a sintering process according to claim 1, characterized in that in each of the composite NCM particles, the total weight ratio of the corresponding plurality of LLZO microparticles and the corresponding NCM particles having the glass phase is in the range of 0.2% to 2%.

10. 2. The method for producing NCM positive electrode particles coated with LLZO and a glass phase by a sintering process according to claim 1, wherein in step C, the rotation speed of the second agitator is in the range of 20 rpm to 500 rpm, and the agitation time is in the range of 2 hours to 12 hours; and in step D, the sintering temperature is in the range of 550°C to 650°C, the heating rate is in the range of 1.5 to 5°C / min, and the maximum temperature holding time is in the range of 0.5 hours to 2 hours.

11. 2. The method for manufacturing NCM positive electrode particles coated with LLZO and a glass phase by a sintering process according to claim 1, further comprising a step E of mixing a plurality of the sintered powders, a plurality of carbon nanotubes (CNTs), and a plurality of nanoscale amorphous carbons with a carbon material to form positive electrode particles coated with a plurality of carbon materials.

12. 12. The method for manufacturing NCM positive electrode particles coated with LLZO and a glass phase by a sintering process according to claim 11, wherein the carbon material mixing method comprises simultaneously feeding the sintered powder, the carbon nanotubes, and the nanoscale amorphous carbons into a dry mixer and mixing them to form the carbon material-coated positive electrode particles, each of which includes a composite NCM particle, and the corresponding carbon nanotubes and nanoscale amorphous carbons coat the exterior of the composite NCM particle, the dry mixer having a stirring rotation speed of 50 rpm to 500 rpm and a stirring time of 2 hours to 8 hours.

13. 12. The method for manufacturing NCM positive electrode particles coated with LLZO and a glass phase by a sintering process according to claim 11, wherein the carbon material mixing method comprises first mixing a plurality of the carbon nanotubes with a plurality of the sintered powders a first time, and then adding a plurality of the nanoscale amorphous carbons to perform a second mixing to form a plurality of positive electrode particles coated with the carbon material, each of the carbon material-coated positive electrode particles including a corresponding composite NCM particle, and the corresponding plurality of carbon nanotubes and a corresponding plurality of nanoscale amorphous carbons coating the exterior of the corresponding composite NCM particle, and the first mixing and the second mixing methods are dry ball mill mixing or wet ball mill mixing.

14. 14. The method for preparing NCM positive electrode particles coated with LLZO and a glass phase by a sintering process according to claim 13, wherein the first mixing and the second mixing are dry ball mill mixing, and the plurality of carbon nanotubes and the plurality of sintered powders are first loaded into a dry ball mill to perform the first mixing by ball milling, and then the plurality of nanoscale amorphous carbons are added to the dry ball mill to perform the second mixing by ball milling to form the plurality of positive electrode particles coated with the carbon material, and the first mixing and the second mixing are performed at a rotation speed of the dry ball mill ranging from 50 rpm to 1000 rpm, a mixing time ranging from 20 minutes to 12 hours, and the ball milling is performed at a room temperature of 50°C.

15. 14. The method for preparing NCM positive electrode particles coated with LLZO and a glass phase by a sintering process according to claim 13, wherein the first mixing and the second mixing are wet ball mill mixing, the carbon nanotubes are first dispersed in a dispersant, and the sintered powder is then introduced into a wet ball mill to perform the first mixing using the wet ball mill. After that, the nanoscale amorphous carbons are added to the wet ball mill, and the second mixing is performed using the wet ball mill to form positive electrode particles coated with the carbon material. In the first mixing and the second mixing, the rotation speed of the wet ball mill is between 50 rpm and 500 rpm, the mixing time is between 20 minutes and 12 hours, and the dispersant is selected from polar and non-polar non-aqueous organic solvents.

16. the size of each of the nanoscale amorphous carbons is in the range of 20 nm to 100 nm, and in each of the positive electrode particles covering the carbon material, each of the nanoscale amorphous carbons is located in a gap formed by the intersection of a corresponding plurality of the carbon nanotubes; 12. The method for manufacturing NCM positive electrode particles coated with LLZO and a glass phase by a sintering process according to claim 11, wherein in each of the positive electrode particles coated with the carbon material, the weight ratio of the total weight of the corresponding plurality of nanoscale amorphous carbons to the weight of the corresponding composite NCM particle is in the range of 0.1% to 2%.

17. 12. The method for manufacturing NCM positive electrode particles coated with LLZO and a glass phase by a sintering process according to claim 11, wherein the plurality of carbon nanotubes comprises a plurality of short-chain carbon nanotubes and a plurality of long-chain carbon nanotubes, each of the short-chain carbon nanotubes having a length ranging from 0.5 μm to 1 μm, each of the long-chain carbon nanotubes having a length ranging from 3 μm to 8 μm, the short-chain carbon nanotubes being used to bridge the corresponding LLZO fine particles and the corresponding NCM large particles, and each of the long-chain carbon nanotubes being used to coat the corresponding composite NCM particles.

18. 12. The method for manufacturing NCM positive electrode particles coated with LLZO and glass phases by a sintering process according to claim 11, characterized in that, in each of the positive electrode particles coated with the carbon material, the weight ratio of the total weight of the corresponding plurality of carbon nanotubes to the weight of the corresponding composite NCM particle is in the range of 0.1% to 2%.

19. 12. The method for manufacturing NCM positive electrode particles coated with LLZO and a glass phase by a sintering process according to claim 11, wherein, in each of the carbon material-coated positive electrode particles, the weight ratio of the total weight of the corresponding plurality of carbon nanotubes and the corresponding plurality of nanoscale amorphous carbons to the weight of the corresponding composite NCM particle is (0.09-3):

100.

20. 12. The method for manufacturing NCM positive electrode particles coated with LLZO and glass phases by a sintering process according to claim 11, wherein in each of the carbon material-coated positive electrode particles, the weight ratio of the corresponding plurality of carbon nanotubes, the corresponding plurality of nanoscale amorphous carbons, and the corresponding composite NCM particles is 0.5:1:100.

Images