Lithium cobalt oxide positive electrode particle coated with oxide and carbon nano tube

Abstract

The utility model discloses an oxide and carbon nano tube coated lithium cobalt oxide positive electrode particle which comprises an LCO large particle which is an irregular cube, a plurality of LLZO large particles and a plurality of LLZO small particles are coated on the outer surface of the LCO large particle, and the whole body forms a composite LCO large particle; wherein the large LLZO particles and the small LLZO particles are distributed on the large LCO particles in a convex arc shape; an LLZO dielectric phase layer is formed between the bottoms of the LLZO large particles and the LCO large particles and between the bottoms of the LLZO small particles and the LCO large particles, and the LLZO dielectric phase layer is mainly used for guiding lithium ions and is secondarily used for protecting the LCO large particles; the lithium ion guiding capability of the large LLZO particles and the small LLZO particles is far higher than that of the large LCO particles, and the large LLZO particles and the small LLZO particles are not prone to side reaction with the lithium ions. The large LLZO particles, the small LLZO particles and the large LCO particles are all of a crystal structure. Wherein CNTs of different sizes are arranged on the peripheries of the composite LCO large particles, and the CNTs integrally wrap the composite LCO large particles. The CNT has a short-chain CNT and a long-chain CNT.

Description

Technical Field

[0001] This utility model relates to the field of cathode material technology, and in particular to a lithium cobalt oxide cathode particle coated with oxide and carbon nanotubes. Background Technology

[0002] A battery consists of a positive electrode and a negative electrode. The positive electrode mainly includes a positive electrode substrate and a positive electrode slurry layer coated on the substrate. The positive electrode slurry layer contains a binder and also includes multiple positive electrode particles. These positive electrode particles are primarily used in the positive electrodes of general solid-state or near-solid-state batteries. The positive electrode particles must possess conductivity or enhance conductivity to allow free electrons to migrate within the positive electrode slurry without consuming excessive energy due to internal resistance, thus achieving effective conductivity. Therefore, the conductivity of the positive electrode particles must be adjusted using specific conductive materials during manufacturing.

[0003] Traditionally, cathode materials can be selected from NCM (lithium nickel manganese cobalt oxide), LCO (lithium cobalt oxide), LMFP (lithium manganese iron phosphate), or mixtures thereof, and these cathode particles are distributed within the cathode slurry. Several techniques exist to improve the lithium-ion conductivity of cathode particles made from these materials; however, it is currently believed that the conductivity of lithium batteries in practical applications remains insufficient. Therefore, it is necessary to modify the materials to further enhance the conductivity of the cathode particles.

[0004] The applicant's other patents have proposed several technologies to increase the conductivity of the entire electrode paste, such as adding carbon nanotubes to the paste to bridge the various positive electrode particles in the positive electrode material, thereby reducing the internal resistance generated when electrons cross the paste to another positive electrode conductive unit, and thus improving the overall conductivity of the positive electrode. The applicant's long-term understanding of such technologies also shows that some chemical substances, such as LLZO (lithium lanthanum zirconium oxide), can produce excellent conductivity in lithium batteries.

[0005] Based on their extensive experience with battery materials, the applicant hopes to propose a novel design that can give the cathode of current solid-state batteries higher capacity and conductivity, thereby further improving battery performance.

[0006] Therefore, existing technologies have shortcomings and need to be improved. Utility Model Content

[0007] The purpose of this invention is to solve the problems of the aforementioned known technologies. This invention proposes a lithium cobalt oxide cathode particle coated with oxide and carbon nanotubes. In this case, after coating the surface of the large LCO particles with oxide particles (LLZO-sized particles), while improving ionic conductivity and protection, the ceramic properties of the oxides also reduce some electronic conductivity. Electron transport and ion transport are interdependent; for good ion transport, in addition to the LLZO and the mesophase layer acting as channels, the electron conduction medium is also crucial. Therefore, the outer ring of the composite large LCO particles is coated with a conductive network composed of carbon nanotubes of various lengths. The main function of the short-chain carbon nanotubes is to provide short-range electron transport capability, thereby facilitating the short-range transport of lithium ions. The main effect of the long-chain carbon nanotubes is to enhance electron transport between multiple LLZO particles (regardless of size) and between the composite large LCO particles and other materials on the electrode plate, creating small electron transport chains that promote ion transport. This improves both electron and ion transport in the entire composite cathode. The coating effect of CNTs (carbon nanotubes) and oxides (LLZO particles of varying sizes) makes it less likely for lithium ions to become blocked on the cathode surface due to poor transport, thus preventing the formation of lithium-consuming products such as SEI with the electrolyte. This improves the lifespan (cycle performance) of the entire composite cathode material. Simultaneously, the excellent lithium-ion and electron transport chains on the composite cathode material also give it better rate performance. As the ion and electron transport of the composite cathode is enhanced, side reactions decrease. The LLZO particles and the mesophase layer provide further protection for the composite cathode, making it less prone to reaction with the electrolyte. This reduces the impact of side reactions caused by electrolyte breakdown and cathode reaction at high voltages, thereby improving its voltage withstand performance and enabling charging and discharging between 4.7V and 4.9V. This protective layer also further reduces oxygen release and gas generation at high voltage, improving the overall cell safety performance.

[0008] To achieve the above objectives, this invention proposes a lithium cobalt oxide cathode particle coated with an oxide and carbon nanotubes, wherein the oxide is LLZO (lithium lanthanum zirconium oxide); this cathode particle is mainly used in the cathode of general solid-state or quasi-solid-state batteries; the cathode particle comprises: a large LCO (lithium cobalt oxide) particle, which is irregularly cubic, with numerous large LLZO particles and numerous small LLZO particles coating the outer surface of the large LCO particle, forming a composite large LCO particle; the large LLZO particles are distributed in a convex arc shape on the large LCO particle, with a high center and gentle ends; a first LLZO mesophase layer is formed between the bottom of the large LLZO particle and the large LCO particle, the main function of which is to guide lithium ions, and secondarily to protect the large LCO particle; the small LLZO particles are distributed in a convex arc shape on the large LCO particle, with a high center and gentle ends; the bottom of the large LLZO particle and the large LCO particle form a first LLZO mesophase layer, the main function of which is to guide lithium ions, and secondarily to protect the large LCO particle; the small LLZO particles are distributed in a convex arc shape on the large LCO particle. The large LCO particles are distributed in a convex arc shape, with a high center and gentle ends. A second LLZO mesophase layer is formed between the bottom of the small LLZO particles and the large LCO particles. Multiple large and small LLZO particles are attached to the outer surface of the large LCO particles. Because the large and small LLZO particles have a much higher ion guiding ability for lithium ions than the large LCO particles, and are less likely to produce side reactions with lithium ions, when lithium ions pass through the positive electrode, the pathway of lithium ions can be dispersed by the guidance of the dispersed large and small LLZO particles. The large LLZO particles, small LLZO particles, and large LCO particles are all crystalline structures, so they have good overall stability and will not easily release or dissociate, thus improving the voltage of the entire battery.

[0009] The LCO macroparticles range in size from 10 to 15 micrometers. The lateral dimensions of the LZO macroparticles range from 100 to 280 nanometers; the lateral dimensions of the LZO microparticles range from 50 to 100 nanometers. The total weight of the numerous LZO macroparticles relative to the weight of a single LCO macroparticle ranges from 0.5 wt% to 0.8 wt%; the total weight of the numerous LZO microparticles relative to the weight of a single LCO macroparticle ranges from 0.1 wt% to 0.3 wt%.

[0010] The first LLZO mesophase layer has a mesophase thickness of 2 nm to 12 nm, and the second LLZO mesophase layer has a mesophase thickness of 2 nm to 12 nm. The first and second LLZO mesophase layers are mainly formed by LLZO, cobalt oxides, and cobalt extensions, and their function is to provide lithium ions with better guiding channels; the cobalt mainly comes from the outer layer of the large LCO particles. The first LLZO mesophase layer comprises an interfacial oxygen-deficient layer and an extension layer generated during sintering. The interfacial oxygen-deficient layer comprises La2Zr2O7 and La2O3, while the extension layer comprises lithium phosphate. Both have a thickness of 1 nm to 10 nm. The extension layer itself also has lithium-ion conductivity. The interfacial oxygen-deficient layer functions as an ion-conducting connection layer and provides protection. The extension layer extends onto the surfaces of the large LCO particles and the LLZO particles of different sizes to form a thin film. The second LLZO mesophase layer comprises an interfacial oxygen-deficient layer and an extension layer generated during sintering. The interfacial oxygen-deficient layer comprises La2Zr2O7 and La2O3, while the extension layer comprises lithium phosphate. Both have a thickness of 1 nm to 10 nm. The extension layer itself also has lithium-ion conductivity. The interfacial oxygen-deficient layer functions as an ion-conducting connection layer and provides protection. The extension layer extends onto the surfaces of the large LCO particles and the LLZO particles of different sizes to form a thin film.

[0011] The composite LCO macroparticles are surrounded by CNTs (carbon nanotubes) of different sizes, which completely encapsulate the composite LCO macroparticles. The CNTs 30 have two lengths: short-chain CNTs 32 with a length of less than 0.5 micrometers to 3 micrometers; and long-chain CNTs 34 with a length of 8 micrometers to 12 micrometers.

[0012] The features and advantages of this work can be further understood from the following description. Please refer to the accompanying drawings while reading. Attached Figure Description

[0013] Figure 1 This is a structural diagram of the case.

[0014] Figure 2 This example illustrates an embodiment of the case.

[0015] Figure 3 This is a magnified structural diagram of this case.

[0016] Figure 4 This is a magnified structural diagram of this case.

[0017] Figure 5 This diagram illustrates the short-chain CNT wrapping in this case. Detailed Implementation

[0018] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0019] Please refer to Figures 1 to 5 As shown, this invention utilizes oxide and carbon nanotube-coated lithium cobalt oxide cathode particles, primarily used as cathodes in general solid-state or solid-state-like batteries. Figure 2 The positive electrode 100 includes:

[0020] A positive electrode substrate 10;

[0021] A positive electrode slurry layer 12 is coated on the positive electrode substrate 10, wherein the positive electrode slurry layer 12 comprises: a positive electrode slurry 14 containing a binder, and the positive electrode slurry layer 12 further comprises:

[0022] Multiple positive electrode particles 200 are distributed within the positive electrode slurry 14. The total weight of these multiple positive electrode particles 200 accounts for 92 wt% to 98 wt% of the positive electrode slurry layer 12.

[0023] Each of the 200 positive electrode particles, namely the oxide and carbon nanotube-coated lithium cobalt oxide positive electrode particles of this case, comprises:

[0024] A large LCO (LiCoO2, lithium cobalt oxide) particle 22, which is an irregular cube, with a size between 10 micrometers and 15 micrometers.

[0025] Numerous LLZO (Li7La3Zr2O) 12 Large LCO particles 24 (lithium lanthanum zirconium oxide) and numerous small LCO particles 26 coat the outer surface of the large LCO particles 22, forming a composite large LCO particle 20. Figure 3 The lateral dimensions (i.e., dimensions along the spherical surface) of the large LLZO particles 24 range from 100 nm to 280 nm; the lateral dimensions (i.e., dimensions along the spherical surface) of the small LLZO particles 26 range from 50 nm to 100 nm. Essentially, after sintering, the longitudinal dimensions of the large LLZO particles 24 and the small LLZO particles 26 shorten, the lateral dimensions widen, and the overall volume remains unchanged. The total weight of the numerous large LLZO particles 24 relative to the weight of a single large LCO particle 22 ranges from 0.5 wt% to 0.8 wt%; the total weight of the numerous small LLZO particles 26 relative to the weight of a single large LCO particle 22 ranges from 0.1 wt% to 0.3 wt%. The LLZO particles are similar to Li... 6.2 Ga 0.8 La3Zr2O 12 (Galan-doped lithium lanthanum zirconium oxide), gallium doping can also be replaced with aluminum (Al) doping or barium (Ba) doping, etc.

[0026] like Figure 3As shown, the large LLZO particles 24 are distributed in a convex arc shape on the large LCO particles 22, with a high center and gentle ends. A first LLZO mesophase layer 25 is formed between the bottom of the large LLZO particles 24 and the large LCO particles 22, which mainly guides lithium ions and secondarily protects the large LCO particles 22. The thickness of the first LLZO mesophase layer 25 is between 2 nanometers and 12 nanometers.

[0027] The first LLZO mesophase layer 25 is mainly formed by LLZO, cobalt oxides, and cobalt extensions (wherein the cobalt mainly comes from the outer layer of the large LCO particles 22). Its function is to provide a good conduction channel for lithium ions. The first LLZO mesophase layer 25 consists of an interface oxygen-deficient layer 251 and an extension layer 252 generated during the sintering process of the large LLZO particles 24 and the large LCO particles 22. The interface oxygen-deficient layer 251 contains La2Zr2O7 and La2O3; while the extension layer 252 contains lithium phosphate; both have a thickness of 1 nm to 10 nm. The first LLZO mesophase layer 25 facilitates the connection between the large LCO particles 22 and the large LLZO particles 24, making them a continuous interface. The extension layer 252 itself also has lithium-ion conductivity, but it is slightly inferior to that of the large LLZO particles 24. The interface oxygen-deficient layer 251 serves as an ion-conducting connection layer and provides protection. The extension layer 252 extends on the surface of the large LCO particles 22 and the surface of the LLZO particles to form a thin film.

[0028] like Figure 4 As shown, the LLZO small particles 26 are distributed in a convex arc shape on the LCO large particles 22, with a shape that is high in the middle and flat at both ends. A second LLZO mesophase layer 27 is formed between the bottom of the LLZO small particles 26 and the LCO large particles 22. The thickness of the second LLZO mesophase layer 27 is between 2 nanometers and 12 nanometers.

[0029] The second LLZO mesophase layer 27 is mainly formed by LLZO, cobalt oxides, and cobalt extensions (primarily derived from the outer layer of the large LCO particles 22). Its function is to provide a good guiding channel for lithium ions. The second LLZO mesophase layer 27 consists of an interface oxygen-deficient layer 271 and an extension layer 272 generated during the sintering process between the small LLZO particles 26 and the large LCO particles 22. The interface oxygen-deficient layer 271 comprises La₂Zr₂O₇ and La₂O₃; while the extension layer 272 comprises lithium phosphate; both have a thickness of 1 nm to 10 nm. The second LLZO mesophase layer 27 facilitates the connection between the large LCO particles 22 and the small LLZO particles 26, making them a continuous interface. The extension layer 272 itself also possesses lithium-ion conductivity, although it is slightly less than that of the small LLZO particles 26. The interface oxygen-deficient layer 271 serves as an ion-conducting connecting layer and provides protection. The extension layer 272 extends on the surface of the large LCO particles 22 and the surface of the LLZO particles to form a thin film.

[0030] In this invention, the small LLZO particles 26 are used to partially replace the large LLZO particles 24, thereby increasing the surface coverage of the small LLZO particles 26 and reducing side reactions. At the same time, the small LLZO particles 26 can also serve as lithium-ion channels for ion transport and reduce the cost of coating the large LCO particles 22.

[0031] In this design, multiple large LLZO particles 24 and small LLZO particles 26 are attached to the outer surface of the large LCO particles 22. Because the large LLZO particles 24 and small LLZO particles 26 have a much higher ion guiding ability for lithium ions than the large LCO particles 22, and are less prone to side reactions with lithium ions, when lithium ions pass through the positive electrode 100, the dispersed large LLZO particles 24 and small LLZO particles 26 can guide and disperse the lithium ion pathway. Therefore, this design allows for better lithium ion pathways, significantly increasing the overall battery performance.

[0032] The large LLZO particles cannot adequately cover the large LCO particles 22, resulting in numerous gaps. Therefore, the gaps between the large LLZO particles must be filled with small LLZO particles. Consequently, using a mixture of large and small particles provides greater stability in terms of process and surface coverage.

[0033] This mesophase layer forms the connection between LCO and LLZO. This mesophase layer contains La₂Zr₂O₇ and a portion of La₂O₃. The more complete the LLZO particles' coating on the larger LCO particles, the less surface area of ​​the larger LCO particles is exposed, thus reducing the probability and amount of side reactions with the electrolyte or colloidal substances, making the cathode material more stable. La₂Zr₂O₇ itself also possesses lithium-ion conductivity; although not as strong as LLZO, it can act as an ion-conducting layer to assist in the conduction of lithium ions from LCO to LLZO. LLZO acts as a fast tunnel for lithium ion conduction, allowing lithium ions from LCO to migrate quickly and efficiently into and out of LLZO after passing through this mesophase layer. Furthermore, La₂Zr₂O₇ itself possesses the inertness of a ceramic compound, reducing side reactions between the cathode and electrolyte, especially under high voltage (>4.5V to 4.9V). This mesophase layer provides passivation and protection for the LCO material.

[0034] The LLZO large particle 24, the LLZO small particle 26, and the LCO large particle 22 in this case are all crystalline structures, so they have good overall stability and will not easily release or dissociate, thus increasing the voltage of the entire battery.

[0035] like Figure 1 The composite LCO large particle 20 has CNT 30 (Carbon Nanotube) of different sizes on its periphery, so the CNT 30 completely covers the composite LCO large particle 20 to form the positive electrode particle 200.

[0036] In this case, the CNT 30 has two lengths: short-chain CNT 32 with a length ranging from 0.5 micrometers to 3 micrometers; and long-chain CNT 34 with a length ranging from 8 micrometers to 12 micrometers. The overall weight ratio of the short-chain CNT 32 to the long-chain CNT 34 is 5:2, and the overall weight of CNT 30 accounts for between 0.01 wt% and 0.5 wt% of the total weight of the LCO large particles 22.

[0037] like Figure 5 As shown, the short-chain CNT 32 can bridge the large LLZO particle 24 and the large LCO particle 22, and also bridge the small LLZO particle 26 and the large LCO particle 22; and the long-chain CNT 34 is used to encapsulate the entire composite large LCO particle 20 (i.e., containing the large LLZO particle 24, the small LLZO particle 26, and the short-chain CNT 32) to enhance the overall structural strength and increase electronic conductivity. CNT is a fairly good conductive material, and when it is attached to the composite large LCO particle 20, it forms a shape like a ball of yarn (e.g., Figure 1 ).

[0038] Carbon nanotubes 30 (CNT 30) are used to increase electronic conductivity by forming conductive bridges around the various large LLZO particles 24 and small LLZO particles 26, allowing electrons to conduct through the composite LCO large particles 20. Because carbon nanotubes have extremely high conductivity, lithium ions can conduct between the different large LLZO particles 24, small LLZO particles 26, and large LCO particles 22 via the carbon nanotubes 30, thus increasing the overall conductivity of the positive electrode 100.

[0039] The preferred LLZO in the large LLZO particles 24 and the small LLZO particles 26 is selected from one of Ga-LLZO (gallium-doped lithium lanthanum zirconium oxide), Cu-LLZO (copper-doped lithium lanthanum zirconium oxide), Ta-LLZO (tantalum-doped lithium lanthanum zirconium oxide), Sr-LLZO (strontium-doped lithium lanthanum zirconium oxide), and Al-LLZO (aluminum-doped lithium lanthanum zirconium oxide).

[0040] Preferably, the LLZO is selected from Cu_a,X_b-LLZO, where X is selected from one of Ga (gallium), Ta (tantalum), Sr (strontium), Ba (barium), and Al (aluminum); and a+b = 0.25-0.8, a>0.1. Using copper doping in LLZO is quite difficult, but it can make the overall structure more stable, the lithium-ion channels smoother, and it increases the sintering speed while being relatively inexpensive to manufacture. It also reduces the formation of lithium carbonate when the material is exposed to air, thus increasing the surface stability of the entire material during sintering.

[0041] In this case, after coating the surface of the large LCO particles 22 with oxide particles (LLZO particles 24 and 26), although the ionic conductivity and protection are improved, the electronic conductivity is reduced to some extent due to the ceramic properties of the oxides. Electron transport and ion transport are interdependent. For ion transport to be effective, in addition to the LLZO and the mesophase layer acting as channels, the electron conduction medium is also very important. Therefore, the outer ring of the composite large LCO particles 20 is coated with a conductive network composed of carbon nanotubes of various lengths. The main function of the short-chain carbon nanotubes is to provide short-range electron transport capability, thereby conducting electrons and making it easier for lithium ions to be transported over short distances. The main effect of the long-chain carbon nanotubes is to enhance the electron transport capability between multiple LLZO particles (regardless of size) and between the composite large LCO particles 20 and other materials on the electrode, creating small electron transport chains to promote ion transport. This improves both electron and ion transport of the entire composite cathode. The coating effect of CNTs and oxides (LLZO particles of varying sizes) makes it less likely for lithium ions to become blocked on the cathode surface due to poor transport, thus preventing the formation of lithium-consuming products such as SEI with the electrolyte. This improves the lifespan (cycle performance) of the entire composite cathode material. Simultaneously, the excellent lithium-ion and electron transport chains on the composite cathode material also give it better rate performance. As the ion and electron transport of the composite cathode is enhanced, side reactions decrease. The LLZO particles and the mesophase layer provide further protection for the composite cathode, making it less prone to reaction with the electrolyte. This reduces the impact of side reactions caused by electrolyte breakdown and cathode reaction at high voltages, thereby improving its voltage withstand performance and enabling charging and discharging between 4.7V and 4.9V. This protective layer also further reduces oxygen release and gas generation at high voltage, improving the overall cell safety performance.

[0042] In conclusion, the human-centered and considerate design of this case is highly in line with actual needs. Its specific improvements over existing deficiencies represent a significant breakthrough compared to known technologies, offering genuinely enhanced functionality that is not easily achieved. Furthermore, since this case has not been publicly disclosed or revealed in domestic or international literature or the market, it complies with patent law requirements.

[0043] The above detailed description is a specific description of one feasible embodiment of the present invention. However, the embodiment is not intended to limit the patent scope of the present invention. All equivalent implementations or modifications made without departing from the spirit of the present invention should be included in the patent scope of this case.

Claims

1. A lithium cobalt oxide cathode particle coated with oxide and carbon nanotubes, characterized in that, The oxide is lithium lanthanum zirconium oxide, i.e., LLZO; the cathode particle is used in the cathode of general solid-state or solid-state-like batteries; the cathode particle comprises: Large lithium cobalt oxide (LCO) particles are irregularly shaped cubic particles. Numerous large LLZO particles and numerous small LLZO particles coat the outer surface of the large LCO particle, forming a composite large LCO particle. The LLZO large particles are distributed in a convex arc shape on the LCO large particles, with a high middle and flat ends. A first LLZO mesophase layer is formed between the bottom of the LLZO large particles and the LCO large particles. Its main function is to guide lithium ions, and its secondary function is to protect the LCO large particles. The LLZO small particles are distributed in a convex arc shape on the LCO large particles, with a shape that is high in the middle and flat at both ends; a second LLZO mesophase layer is formed between the bottom of the LLZO small particles and the LCO large particles. Multiple large and small LLZO particles are attached to the outer surface of the large LCO particles. Because the large and small LLZO particles have a much higher ion guiding ability for lithium ions than the large LCO particles, and are less likely to produce side reactions with lithium ions, when lithium ions pass through the positive electrode, the pathway of lithium ions can be dispersed by the guidance of the dispersed large and small LLZO particles. The large LLZO particles, the small LLZO particles, and the large LCO particles all have a crystalline structure, so they have good overall stability and will not easily release or dissociate, thus improving the overall battery voltage.

2. The lithium cobalt oxide cathode particles coated with oxide and carbon nanotubes as described in claim 1, characterized in that, The LCO particles are between 10 and 15 micrometers in size.

3. The lithium cobalt oxide cathode particles coated with oxide and carbon nanotubes as described in claim 1, characterized in that, The lateral dimensions of the large LLZO particles range from 100 nanometers to 280 nanometers; the lateral dimensions of the small LLZO particles range from 50 nanometers to 100 nanometers.

4. The lithium cobalt oxide cathode particles coated with oxide and carbon nanotubes as described in claim 1, characterized in that, The total weight of the numerous large LLZO particles relative to the weight of a single large LCO particle is between 0.5 wt% and 0.8 wt%; the total weight of the numerous small LLZO particles relative to the weight of a single large LCO particle is between 0.1 wt% and 0.3 wt%.

5. The lithium cobalt oxide cathode particles coated with oxide and carbon nanotubes as described in claim 1, characterized in that, The thickness of the first LLZO mesophase layer is between 2 nanometers and 12 nanometers; the thickness of the second LLZO mesophase layer is between 2 nanometers and 12 nanometers.

6. The lithium cobalt oxide cathode particles coated with oxide and carbon nanotubes as described in claim 1, characterized in that, The composite LCO macroparticles have CNTs of different sizes on their periphery, which completely encapsulate the composite LCO macroparticles.

7. The lithium cobalt oxide cathode particles coated with oxide and carbon nanotubes as described in claim 6, characterized in that, The CNT has two lengths: short-chain CNTs with a length between 0.5 micrometers and 3 micrometers; and long-chain CNTs with a length between 8 micrometers and 12 micrometers. The short-chain CNTs are used to bridge the large LLZO particles and the large LCO particles, as well as to bridge the small LLZO particles and the large LCO particles. The long-chain CNTs are used to encapsulate the composite large LCO particles containing the short-chain CNTs.

8. The lithium cobalt oxide cathode particles coated with oxide and carbon nanotubes as described in claim 1, characterized in that, The LLZO in the large and small LLZO particles is selected from one of Ga-LLZO, Cu-LLZO, Ta-LLZO, Sr-LLZO, and Al-LLZO.

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