LCO cathode particles coated with oxides and carbon nanotubes

Abstract

To provide an LCO positive electrode particle coated with an oxide and a carbon nanotube.SOLUTION: The LCO cathode particle 200 coated with the oxide and the carbon nanotube 30 is used for a cathode of solid-state or solid-state batteries. The positive electrode particle 200 includes a composite LCO particle containing an LCO (lithium cobalt oxide) large particle 22 having an irregular cubic shape, and a plurality of LLZO large particles 24 and a plurality of LLZO small particles 26 covering the outer surface of the LCO large particle 22. A first side 1LLZO dielectric layer is formed between the bottom of each of the LLZO large particles 24 and the LCO large particles 22. A first 2LLZO dielectric layer is formed between the bottom of each of the small LLZO particles 26 and the large LCO particles 22. The outer periphery of the composite LCO particle further has a plurality of short-chain carbon nanotubes and a plurality of long-chain carbon nanotubes 34 having different sizes and covering the entire composite LCO particle.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This invention relates to cathode particles, and more specifically to LCO cathode particles coated with oxides and carbon nanotubes. [Background technology]

[0002] A battery consists of a positive electrode and a negative electrode. The cathode of a battery is the positive electrode inside the battery, and the positive electrode mainly comprises a positive electrode substrate and a positive electrode slurry layer coated on the positive electrode substrate, the positive electrode slurry layer containing a positive electrode slurry with a binder and a plurality of positive electrode particles. Positive electrode particles are mainly used as positive electrodes in general solid or solid-state batteries. Positive electrode particles need to have guiding properties or conductivity, and achieve the objective of effective conductivity by enabling free electrons to transition in the positive electrode slurry and preventing excessive energy consumption due to internal electrical resistance. Therefore, when manufacturing positive electrode particles, it was necessary to consider adjusting the conductivity of the positive electrode particles using specific conductive materials. [Overview of the project] [Problems that the invention aims to solve]

[0003] Conventional cathode particle materials are selected from LCO (lithium cobalt oxide), LMFP (lithium iron manganese phosphate), or mixtures thereof, and these cathode particles are distributed within the cathode slurry. While many techniques already exist in the prior art to enhance the guiding ability of cathode particles to lithium ions, lithium batteries currently still lack sufficient conductivity for practical use.

[0004] Therefore, the present invention provides a novel design that further enhances the effectiveness of a battery by having even higher capacitance and conductivity than the positive electrode of conventional solid batteries.

[0005] This invention has been made in view of the above circumstances, and one of its objectives is to solve the problems described above. Specifically, the present invention provides LCO cathode particles coated with oxide and carbon nanotubes. [Means for solving the problem]

[0006] To solve the above problems, LCO cathode particles coated with oxide and carbon nanotubes according to one embodiment of the present invention have the surface of the large LCO particles coated with large / small LLZO particles and a dielectric layer to form composite LCO particles, thereby enhancing ion conductivity and protective capabilities. Since electron transport and ion transport are interdependent, and to address the situation where partial electron conduction decreases due to the ceramic properties of the oxide mentioned above, the present invention coats the outer surface of the composite LCO particles with an electron-conducting medium, i.e., a conductive network formed by combining carbon nanotubes of various lengths. Short-chain carbon nanotubes can provide short-distance electron transport capability for conducting electrons, allowing lithium ions to be transported more easily over short distances. Long-chain carbon nanotubes can provide electron transport capability between multiple large / small LLZO particles and the composite LCO particles and other materials in the cathode substrate, improving electron and ion transport throughout the cathode by forming small electron transport systems and promoting ion transport. The coating effect of carbon nanotubes and large / small LLZO particles makes it less likely for lithium ions to be hindered by poor transport at the cathode surface. Furthermore, it forms lithium-consuming products such as SEI (Solid Electrolyte Interface) films together with the electrolyte. This extends the lifespan of the entire cathode material, i.e., improves circulation performance. In addition, the excellent lithium ion and electron transport system of the composite cathode material according to the present invention achieves even higher magnification performance. The improved ion-electron transport of the composite cathode reduces side reactions. Moreover, the LLZO particles and the dielectric layer provide even more protection, making the entire cathode material less likely to react with the electrolyte, less likely to disintegrate with the electrolyte at high voltages, less susceptible to the effects of side reactions that occur after reaction with the cathode, and improving dielectric strength. It enables charging and discharging in the range of 4.7V to 4.9V, and further reduces high-pressure oxygen release and gas generation from the cathode, improving overall safety.

[0007] The following information will become clear from the description in the specification and drawings described later. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic diagram showing LCO cathode particles coated with oxide and carbon nanotubes according to one embodiment of the present invention. [Figure 2] This figure shows an example of LCO cathode particles coated with oxide and carbon nanotubes according to the present invention. [Figure 3] This is a schematic enlarged view showing the configuration according to one embodiment of the present invention. [Figure 4] This is a schematic enlarged view showing a configuration according to another embodiment of the present invention. [Figure 5] This is a schematic diagram showing the short-chain carbon nanotubes according to the present invention. [Modes for carrying out the invention]

[0009] The present invention will be described below through embodiments of the invention, but these embodiments are not intended to limit the invention as defined in the claims. Furthermore, not all combinations of features described in the embodiments are necessarily essential to the solution of the invention.

[0010] The LCO cathode particles coated with oxides and carbon nanotubes according to the present invention will be described in detail below with reference to Figures 1 to 5.

[0011] The LCO cathode particles coated with an oxide and carbon nanotubes according to the present invention are wherein the oxide is lithium lanthanum zirconium oxide (Li7La3Zr2O 12 ) or lithium lanthanum zirconium oxide doped with at least one metallic element. The positive electrode particles 200 are used in the positive electrode 100 of a solid or solid-state battery (see Figure 2). The positive electrode 100 comprises a positive electrode substrate 10 and a positive electrode slurry layer 12 coated on the positive electrode substrate 10. The positive electrode slurry layer 12 includes a positive electrode slurry 14 having a binder and a plurality of positive electrode particles 200 distributed within the positive electrode slurry 14. The total weight of the plurality of positive electrode particles 200 accounts for 92 wt% to 98 wt% of the weight % of the positive electrode slurry layer 12.

[0012] The positive electrode particle 200 according to the present invention comprises composite LCO particles 20, the composite LCO particles 20 comprising large LCO particles 22 exhibiting an irregular cubic shape, the size of the large LCO particles 22 being in the range of 10 μm to 15 μm, and further comprising a plurality of large LLZO particles 24 and a plurality of small LLZO particles 26 covering the outer surface of the large LCO particles 22 (see Figure 3). The lateral size of the large LLZO particles 24 (i.e., the size in the direction along the sphere of the corresponding composite LCO particle 20) is in the range of 100 nm to 280 nm, and the lateral size of the small LLZO particles 26 (i.e., the size in the direction along the sphere of the corresponding large LCO particle 22) is in the range of 50 nm to 100 nm. The large LLZO particles 24 and small LLZO particles 26 cover the outer surface of the large LCO particles 22 by sintering. After sintering, the vertical size becomes shorter and the horizontal size becomes wider, but the total volume remains unchanged. The weight ratio of the multiple large LLZO particles 24 to the large LCO particles 22 is in the range of 0.5 wt% to 0.8 wt%, and the weight ratio of the multiple small LLZO particles 26 to the large LCO particles 22 is in the range of 0.1 wt% to 0.3 wt%.

[0013] Each of the LLZO large particles 24 and each of the LLZO small particles 26 are lithium lanthanum zirconium oxide (Li7La3Zr2O 12 Formed of lithium lanthanum zirconium oxide doped with at least one metallic element (e.g., Li lanthanum zirconium oxide, LLZO) or Li lanthanum zirconium oxide doped with at least one metallic element. 6.2 Ga 0.8 La3Zr2O 12 This may be a gallium (Ga)-doped lithium lanthanum zirconate compound, or an aluminum (Al) or barium (Ba)-doped lithium lanthanum zirconate compound.

[0014] As shown in Figure 3, the contour of the longitudinal cross-section (i.e., the cross-section perpendicular to the transverse direction) of each LLZO large particle 24 in the LCO large particle 22 exhibits an arc-shaped projection with a higher central portion and flatter ends on both sides. A first LLZO dielectric layer 25 is formed between the bottom of each LLZO large particle 24 and the LCO large particle 22, and is used to guide lithium ions and protect the LCO large particle 22. The thickness of the intermediate layer of the first LLZO dielectric layer 25 is in the range of 2 nm to 12 nm.

[0015] The first LLZO dielectric layer 25 is mainly formed of lithium lanthanum zirconium oxide or lithium lanthanum zirconium oxide, cobalt (Co) oxide, and cobalt derivatives doped with at least one metal element (the cobalt mainly comes from the outer layer of the LCO large particles 22). Its function is to provide lithium ions having a preferred guide channel. The first LLZO dielectric layer 25 comprises a first interface oxygen-deficient layer 251 and a first derivative layer 252 generated by each of the LLZO large particles 24 and the LCO large particles 22 during the sintering process. The first interface oxygen-deficient layer 251 contains lanthanum zirconate (La2Zr2O7) and lanthanum oxide (La2O3). The first derivative layer 252 contains lithium phosphate (Li3PO4), and the thickness of the first interface oxygen-deficient layer 251 and the first derivative layer 252 is in the range of 1 nm to 10 nm. The first LLZO dielectric layer 25 facilitates the connection between the large LCO particles 22 and the large LLZO particles 24, forming a continuous interface. The first derived layer 252 itself also has the ability to conduct lithium (Li) ions, but it is slightly less capable than the large LLZO particles 24, and is used to protect the first interface oxygen-deficient layer 251 as a connecting layer for ion conduction. The first derived layer 252 is derived from the surface of the large LCO particles 22, the surface of the large LLZO particles 24, and the surface of the small LLZO particles 26, forming a thin film.

[0016] As shown in Figure 4, the vertical cross-section (i.e., the cross-section perpendicular to the horizontal direction) of each LLZO small particle 26 in the LCO large particle 22 exhibits an arc-shaped projection with a higher central portion and flatter ends on both sides. A second LLZO dielectric layer 27 is formed between the bottom of each LLZO small particle 26 and the LCO large particle 22, and the thickness of the intermediate layer of the second LLZO dielectric layer 27 is in the range of 2 nm to 12 nm.

[0017] The second LLZO dielectric layer 27 is mainly formed of lithium lanthanum zirconium oxide or lithium lanthanum zirconium oxide, cobalt oxide, and cobalt derivatives doped with at least one metal element (the cobalt is mainly obtained from the outer layer of the large LCO particles 22). Its function is to provide lithium ions with preferred guide channels. The second LLZO dielectric layer 27 comprises a second interface oxygen-deficient layer 271 and a second derived layer 272 generated during the sintering process of the small LLZO particles 26 and the large LCO particles 22. The second interface oxygen-deficient layer 271 contains lanthanum zirconate (La2Zr2O7) and lanthanum oxide (La2O3), and the second derived layer 272 contains lithium phosphate (Li3PO4). The thickness of the second interface oxygen-deficient layer 271 and the second derived layer 272 is in the range of 1 nm to 10 nm. The second LLZO dielectric layer 27 facilitates the connection between the large LCO particles 22 and the small LLZO particles 26, forming a continuous interface. The second derivative layer 272 itself also has the ability to conduct lithium ions, although it is slightly less capable than the small LLZO particles 26. The second interface oxygen-deficient layer 271 is used as an ion conduction connecting layer for protection. The second derivative layer 272 branches out onto the surfaces of the large LCO particles 22, the large LLZO particles 24, and the small LLZO particles 26, forming a thin film.

[0018] The plurality of said LLZO small particles 26 are used to replace part of said LLZO large particles 24, and the plurality of said LLZO small particles 26 increase the surface coverage and reduce side reactions. In addition, said LLZO small particles 26 also serve as lithium ion channels, transmit ions, and reduce the cost of coating said LCO large particles 22.

[0019] In the present invention, the plurality of LLZO large particles 24 and the plurality of LLZO small particles 26 are attached to the outer surface of the LCO large particles 22. Each of the LLZO large particles 24 and each of the LLZO small particles 26 has a far higher ion guiding capability for lithium ions than the LCO large particles 22, and is less prone to causing side reactions with lithium ions. Therefore, when lithium ions pass through the positive electrode 100, they are guided by the plurality of dispersed LLZO large particles 24 and the plurality of LLZO small particles 26, so that the passages for lithium ions are dispersed. Accordingly, the present invention enables lithium ions to have more favorable passages, and greatly enhances the performance of the battery.

[0020] Since the LLZO large particles 24 cannot appropriately coat the LCO large particles 22, many gaps are formed. Therefore, it is necessary to fill the gaps between the respective LLZO large particles 24 with the LLZO small particles 26. By doing so, stable process and surface coverage are achieved using this mixing method.

[0021] The first dielectric layer 25 and the second dielectric layer 27 form connections among the large LCO particles 22, the plurality of large LLZO particles 24, and the plurality of small LLZO particles 26. The first dielectric layer 25 and the second dielectric layer 27 comprise La₂Zr₂O₇ and partial La₂O₃. The more complete the coverage of the plurality of large LLZO particles 24 and the plurality of small LLZO particles 26 on the large LCO particles 22, the less exposed surface of the large LCO particles 22 there is, whereby both the probability and amount of side reactions occurring with an electrolyte solution or colloidal substance are reduced, and the cathode particles are further stabilized. The La₂Zr₂O₇ itself also has lithium ion conduction capability. Although the conduction capability thereof is inferior to that of the large LLZO particles 24 and the small LLZO particles 26, it can, as an ion conductive layer, assist in conducting lithium ions of the large LCO particles 22 to the large LLZO particles 24 and the small LLZO particles 26. The large LLZO particles 24 and the small LLZO particles serve as high-speed tunnels for conducting lithium ions, allowing the lithium ions of the large LCO particles 22 to reach the large LLZO particles 24 and the small LLZO particles 26 via the first dielectric layer 25 and the second dielectric layer 27, and then enter and exit effectively at high speed. In addition, the La₂Zr₂O₇ itself also has the inertness of a ceramic compound, and can reduce side reactions between the cathode and the electrolyte solution. In particular, under high voltage conditions (>4.5V to 4.9V), the first dielectric layer 25 and the second dielectric layer 27 can provide an LCO material having passivation and protection effects.

[0022] Each of the large LLZO particles 24, each of the small LLZO particles 26, and the large LCO particles 22 all have a crystalline structure, so that they have good overall stability and do not easily dissolve or dissociate. Therefore, the voltage of the entire battery can be increased.

[0023] The outer periphery of the composite LCO particles 20 further comprises a plurality of carbon nanotubes 30 (CNT) of different sizes, and the plurality of carbon nanotubes 30 cover the composite LCO particles 20 to form the cathode particles 200 (see FIG. 1).

[0024] The carbon nanotube 30 comprises a plurality of short-chain carbon nanotubes 32 and a plurality of long-chain carbon nanotubes 34, the length of each of the short-chain carbon nanotubes 32 being in the range of 0.5 μm to 3 μm, and the length of each of the long-chain carbon nanotubes 34 being in the range of 8 μm to 12 μm. The weight ratio of the plurality of short-chain carbon nanotubes 32 to the plurality of long-chain carbon nanotubes 34 is 5:2, and the weight ratio of the plurality of carbon nanotubes 30 to the LCO large particles 22 is in the range of 0.01% to 0.5%.

[0025] As shown in Figure 5, the short-chain carbon nanotubes 32 can span across the corresponding LLZO large particles 24 and LCO large particles 22, and also span across the corresponding LLZO small particles 26 and LCO large particles 22. The long-chain carbon nanotubes 34 are used to coat the composite LCO particles 20, and by coating multiple LLZO large particles 24, multiple LLZO small particles 26, and multiple short-chain carbon nanotubes 32, the overall structural strength is enhanced and electron conductivity is increased. Multiple carbon nanotubes 30 are very good conductive materials and form a fuzzy morphology when attached to the composite LCO particles 20 (see Figure 1).

[0026] Multiple carbon nanotubes 30 are used to increase electron conduction. Specifically, by forming conductive bridges around each of the large LLZO particles 24 and each of the small LLZO particles 26, electrons can conduct through the composite LCO particles 20. Because the carbon nanotubes 30 have extremely high conductivity, lithium ions can conduct through the carbon nanotubes 30 between the different large LLZO particles 24, small LLZO particles 26, and large LCO particles 22, thereby improving the overall conductivity of the positive electrode 100.

[0027] Each of the large LLZO particles 24 and each of the small LLZO particles 26 is composed of at least one 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).

[0028] Preferably, each of the large LLZO particles 24 and each of the small LLZO particles 26 is Cu a ,X b -LLZO, and said Cu a ,X b -LLZO is lithium lanthanum zirconium oxide doped with copper and element X, wherein X is selected from Ga (gallium), Ta (tantalum), Sr (strontium), Ba (barium), and Al (aluminum), and a>0 and b>0. Preferably, a+b=0.25 to 0.8, and a>0.1. It is very difficult to use the technology of doping copper into LLZO, however, the entire structure is more stable, lithium ion channels are smoother, the sintering rate is increased, and the manufacturing cost is also reduced. In addition, the formation of lithium carbonate (Li₂CO₃) when said LLZO material is exposed to air is reduced, that is, the stability of the surface of the entire material during sintering is improved.

[0029] The advantage of this invention is that the surface of large LCO particles is coated with large and small LLZO particles and a dielectric layer to form composite LCO particles, thereby improving ion conductivity and protective capabilities. Since electron and ion transport are interdependent, and to address the situation where partial electron conductivity decreases due to the ceramic properties of the oxide mentioned above, this invention coats the outer surface of the composite LCO particles with an electron-conducting medium, i.e., a conductive network formed by combining carbon nanotubes of various lengths. Short-chain carbon nanotubes can provide short-distance electron transport capability for conducting electrons, allowing lithium ions to be transported more easily over short distances. Long-chain carbon nanotubes can provide electron transport capability between multiple large / small LLZO particles and the composite LCO particles and other materials in the cathode substrate, improving overall electron and ion transport in the cathode by forming small electron transport systems and promoting ion transport. The coating effect of carbon nanotubes and large / small LLZO particles makes it less likely for lithium ions to be hindered by poor transport at the cathode surface. Furthermore, together with the electrolyte, lithium-consuming products such as SEI (Solid Electrolyte Interface) films are formed. The overall lifespan of the positive electrode particles is extended, i.e., the circulation performance is improved. Furthermore, the excellent lithium ion and electron transport system of the composite positive electrode particles according to the present invention achieves even higher magnification performance. The improved ion-electron transport of the composite positive electrode reduces side reactions. In addition, the LLZO particles and the dielectric layer provide more protection, making the entire positive electrode particle less likely to react with the electrolyte, less likely to disintegrate with the electrolyte at high voltages, less susceptible to the effects of side reactions that occur after reaction with the positive electrode, and improving the voltage withstand performance. It is possible to charge and discharge in the range of 4.7V to 4.9V, and the high-pressure oxygen release and gas generation of the positive electrode are further reduced, improving overall safety.

[0030] Although the present invention has been described above using embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It will be obvious to those skilled in the art that various modifications or improvements can be made to the above embodiments. Furthermore, it will be obvious to those skilled in the art that such modifications or improvements can be made. Moreover, it will be clear from the claims that such modified or improved forms may also be included within the technical scope of the present invention. [Explanation of Symbols]

[0031] 10 Positive electrode substrate 12. Positive electrode slurry layer 14 Positive electrode slurry 20 Composite LCO particles 22 LCO large particle 24 LLZO large particle 25. First LLZO dielectric layer 26 LLZO small particles 27. Second LLZO dielectric layer 30 Carbon nanotubes 32 Short-chain carbon nanotubes 34 Long-chain carbon nanotubes 100 positive electrode 200 positive electrode particles 251 First interface oxygen-deficient layer 252 1st derived layer 271 Second interface oxygen-deficient layer 272 Second derived layer

Claims

1. LCO cathode particles coated with an oxide and carbon nanotubes, wherein the oxide is lithium lanthanum zirconium oxide (Li 7 La 3 Zr 2 O 12 ) or lithium lanthanum zirconium oxide doped with at least one metal element, the cathode particles are used for a cathode of a solid-state battery, the cathode particles comprise composite LCO particles, the composite LCO particles comprise large LCO (LiCoO 2 , lithium cobaltate) particles, and a plurality of large LLZO particles and a plurality of small LLZO particles coating the outer surface of the large LCO particles, each of the large LLZO particles and each of the small LLZO particles being formed of lithium lanthanum zirconium oxide (Li 7 La 3 Zr 2 O 12 , LLZO) or lithium lanthanum zirconium oxide doped with at least one metal element, a lateral size of each of the large LLZO particles ranges from 100 nm to 280 nm, a lateral size of each of the small LLZO particles ranges from 50 nm to 100 nm, and the lateral size is a size along the spherical surface direction of the corresponding large LCO particle, Here, the cross-section of each LLZO large particle in the corresponding LCO large particle exhibits an arc-shaped projection with a higher central portion and flatter ends on both sides, and a first LLZO dielectric layer is formed between the bottom of each LLZO large particle and the LCO large particle to guide lithium ions and protect the LCO large particle. The cross-section of each LLZO small particle in the LCO large particle exhibits an arc-shaped projection with a higher central portion and flatter ends on both sides, and a second LLZO dielectric layer is formed between the bottom of each LLZO small particle and the LCO large particle. The ion-guiding ability of the multiple LLZO large particles and multiple LLZO small particles for lithium ions is higher than that of the LCO large particles, and they are less likely to cause side reactions with lithium ions. When lithium ions pass through the positive electrode, they are guided by the dispersed multiple LLZO large particles and multiple LLZO small particles, and the path for lithium ions is dispersed. LCO cathode particles coated with oxide and carbon nanotubes, characterized in that each of the LLZO large particles, each of the LLZO small particles, and the LCO large particles all have a crystalline structure.

2. The LCO cathode particles coated with oxide and carbon nanotubes according to claim 1, characterized in that the weight ratio of a plurality of LLZO large particles to the LCO large particles is in the range of 0.5 wt% to 0.8 wt%, and the weight ratio of a plurality of LLZO small particles to the LCO large particles is in the range of 0.1 wt% to 0.3 wt%.

3. The first LLZO dielectric layer and the second LLZO dielectric layer are made of lithium lanthanum zirconium oxide (Li 7 La 3 Zr 2 O 12 LCO cathode particles coated with an oxide and carbon nanotubes, characterized in that they are formed of lithium lanthanum zirconium oxide doped with at least one metal element, and cobalt oxide and cobalt derivatives, as described in claim 1.

4. The second LLZO dielectric layer comprises a second interface oxygen-deficient layer and a second derivative layer, wherein the second interface oxygen-deficient layer is composed of lanthanum zirconate (La). 2 Zr 2 O 7 ) and lanthanum oxide (La 2 O 3 ) is included, and lithium phosphate (Li) is a component of the second derived layer. 3 PO 4 LCO cathode particles coated with oxide and carbon nanotubes according to claim 1, characterized in that the second derivative layer has the ability to conduct lithium ions, the second interface oxygen-deficient layer is used to protect as an ion conduction connection layer, and the second derivative layer is a thin film formed on the surface of the large LCO particles, the surface of the large LLZO particles, and the surface of the small LLZO particles.

5. The LCO cathode particle coated with oxide and carbon nanotubes according to claim 1, further comprising a plurality of carbon nanotubes of different sizes on the outer circumference of the composite LCO particle, wherein the plurality of carbon nanotubes coat the entire composite LCO particle.

6. The plurality of carbon nanotubes comprises a plurality of short-chain carbon nanotubes and a plurality of long-chain carbon nanotubes, the length of each of the short-chain carbon nanotubes being in the range of 0.5 μm to 3 μm, and the length of each of the long-chain carbon nanotubes being in the range of 8 μm to 12 μm. LCO cathode particles coated with oxides and carbon nanotubes according to claim 5, characterized in that each of the short-chain carbon nanotubes is used to span each of the LLZO large particles and the LCO large particles, and each of the LLZO small particles and the LCO large particles, and the plurality of long-chain carbon nanotubes are used to coat the plurality of short-chain carbon nanotubes and the composite LCO particles.

7. The LCO cathode particles coated with oxide and carbon nanotubes according to claim 6, characterized in that the weight ratio of the plurality of carbon nanotubes to the LCO large particles is in the range of 0.01 wt% to 0.5 wt%, and the weight ratio of the plurality of short-chain carbon nanotubes to the plurality of long-chain carbon nanotubes is 5:

2.

8. LCO cathode particles coated with an oxide and carbon nanotubes, characterized in that each of the large LLZO particles and each of the small LLZO particles are composed of at least one of the following: 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).

9. Each of the aforementioned LLZO large particles and each of the aforementioned LLZO small particles is Cu a ,X b - Composed of LLZO, the Cu a ,X b -LLZO is a 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>0 and b>0, and the Cu a ,X b -LLZO is used to further stabilize the overall structure of the composite LCO particles, to further smooth the lithium ion channels, to accelerate the sintering rate in an oxygen atmosphere, and to reduce the formation of lithium carbonate when exposed to air, as described in claim 1, characterized in that the oxide and carbon nanotube-coated LCO cathode particles.

10. The Cu a ,X b -LCO cathode particles coated with an oxide and carbon nanotubes according to claim 9, characterized in that a+b=0.25-0.8 and a>0.1 in LLZO.

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