NCM cathode particles coated with Ga-LLZO, LATP and CNT

Abstract

A cathode structure for lithium nickel-cobalt-manganese (NCM) cathode particles coated with gallium-doped lithium lanthanum zirconium oxide (Ga-LLZO), lithium aluminum titanium phosphate (LATP), and carbon nanotubes (CNTs) comprises: a cathode substrate; a cathode slurry layer coated on the cathode substrate, wherein the cathode slurry layer comprises: a cathode slurry containing a binder, and a plurality of cathode particles, each comprising: a large NCM particle; the outer surface of the particle is coated with numerous Ga-LLZO fine particles and numerous LATP fine particles, forming a composite large NCM particle; wherein the Ga-LLZO fine particles... The LATP fine particles are distributed in a convex arc shape on the NCM large particles; a Ga-LLZO mesophase layer is formed between the bottom of the Ga-LLZO fine particles and the NCM large particles, and an LATP mesophase layer is formed between the bottom of the LATP fine particles and the NCM large particles; the lithium ion pathway is dispersed by the guidance of the dispersed Ga-LLZO fine particles; the LATP fine particles can prevent the NCM large particles from being corroded by the electrolyte, and the LATP fine particles have a higher lithium ion capacity and flow equalization ability. The composite NCM large particles are coated with CNTs, which are short-chain CNTs with a length between 0.5 micrometers and 1 micrometer.

Description

Technical Field

[0001] The present invention relates to anode materials, in particular to NCM cathode particles coated with Ga-LLZO, LATP and CNT. Prior Art Batteries primarily consist of positive and negative electrodes placed in an electrolyte. The positive electrode consists of numerous positive conductive units (positive electrode materials, such as lithium cobalt oxide) dispersed in a slurry. Generally, the positive conductive units must be mixed with a conductive slurry before they can be applied to the electrode sheets and assembled into a battery. Therefore, the numerous positive conductive units (positive electrode materials) are connected to each other through the conductive slurry. Therefore, the conductive slurry must possess conductive properties, or electrical conductivity, to enable free electrons to migrate between the various positive conductive units without consuming excessive energy due to internal resistance, achieving effective conduction. Therefore, when preparing the slurry, consideration must be given to adjusting the conductivity of the slurry using specific conductive materials. Generally, in order to increase conductivity, a plurality of positive electrode particles are filled in the positive electrode slurry, wherein the material of the positive electrode particles can be selected from NCM (lithium nickel cobalt manganese oxide), LMFP (lithium manganese iron phosphate), etc. or a mixture thereof, and the positive electrode particles are distributed in the positive electrode slurry. In other patents filed by the applicant, in order to further increase the conductivity of the entire slurry, carbon nanotubes are added to the slurry to coat the positive electrode particles in the battery's positive electrode material, thereby reducing the internal resistance generated by electrons crossing the slurry to another positive electrode conductive unit, thereby improving the conductivity of the entire positive electrode. The above conventional technologies are mainly used to increase the overall conductivity of the contents in the positive electrode slurry, thereby increasing the capacitance and conductivity of the entire positive electrode. Based on the applicant's long-term experience in battery materials, the applicant hopes to propose a new design that can make the positive electrode of today's solid-state batteries have higher capacity and conductivity, thereby further improving the performance of the battery. Summary of the Invention The present invention aims to address the aforementioned problems of the prior art. It proposes a NCM positive electrode particle coated with Ga-LLZO, LATP, and CNTs. The present invention forms a large NCM particle whose outer surface is coated with numerous fine Ga-LLZO and LATP particles. This is because the LATP particles have a much higher capacity for accommodating and distributing lithium ions than the large NCM particles, protecting them from electrolyte corrosion and extending the battery's lifespan. Furthermore, numerous fine Ga-LLZO particles are attached to the surfaces of the large NCM particles, each also capable of accommodating and distributing lithium ions. Therefore, when lithium ions pass through the positive electrode, they are guided by the dispersed Ga-LLZO and LATP particles, providing a more dispersed path for the ions. This positive electrode design provides a more efficient path for the lithium ions. Furthermore, the large NCM particles coated with Ga-LLZO and LATP particles are coated with carbon nanotubes, or CNTs. The carbon nanotubes form conductive bridges around the various Ga-LLZO and LATP fine particles, allowing electrons to flow through the composite NCM large particles. This design stabilizes the overall cathode slurry structure, thereby reducing cobalt usage. To achieve the above-mentioned purpose, the present invention proposes an NCM positive electrode particle coated with Ga-LLZO, LATP and CNT, comprising: a positive electrode substrate, which is a carrier for carrying a positive electrode material; a positive electrode slurry layer coated on the positive electrode substrate, wherein the positive electrode slurry layer comprises: a positive electrode slurry containing a binder; a plurality of positive electrode particles distributed in the positive electrode slurry, each of the positive electrode particles comprising: an NCM (lithium nickel cobalt manganese oxide) large particle; wherein the NCM large particle is in an irregular cubic shape, and its outer surface is coated with a plurality of Ga-LLZO (gallium-doped lithium lanthanum zirconium oxide) fine particles and a plurality of LATP (Li1+XAl​​XTi2-x(PO4)3) fine particles, which form a composite NCM large particle as a whole; wherein the Ga-LLZO fine particles are distributed on the NCM large particle in a convex arc shape, with a high middle and flat ends; the bottom of the Ga-LLZO fine particle is A Ga-LLZO interphase layer is formed between the top of the positive electrode and the NCM large particle, and its main function is to guide lithium ions and secondly to protect the NCM large particle; wherein the LATP fine particle is distributed in a convex arc shape on the NCM large particle, which is a type of shape with a high middle and flat ends; a LATP interphase layer is formed between the bottom of the LATP fine particle and the NCM large particle, and its main function is to serve as a protective layer and secondly to guide lithium ions; when lithium ions pass through the positive electrode, the path of lithium ions can be dispersed by the guidance of the dispersed Ga-LLZO fine particles; and the LATP fine particles can prevent the NCM large particle from being corroded by the electrolyte, and the LATP fine particles have a higher lithium ion accommodation and current equalization capacity for lithium ions; the Ga-LLZO fine particles, the LATP fine particles and the NCM large particle are all crystalline structures; wherein the outer periphery of the composite NCM large particle is coated with CNT (Carbon Nanoparticles). Nanotube, carbon nanotube), the CNT is a short-chain CNT with a length ranging from 0.5 microns to 1 micron. The features and advantages of the present invention can be further understood from the following description, which should be read with reference to the accompanying drawings. Simple diagram description FIG1 shows the structure of the positive electrode particles in this case. FIG2 shows the structure of the positive electrode of this case. FIG3 shows the structure of the composite NCM large particles in this case. FIG4 shows the structure of the composite NCM large particles in this case. Implementation Method The structural composition of this case, as well as the effects and advantages it can produce, are described in detail below with reference to the drawings and a preferred embodiment of this case. 1 to 4 , which show the NCM positive electrode particles coated with Ga-LLZO, LATP and CNT of the present invention, including the following elements: As shown in FIG2 , a typical positive electrode 100 of a solid-state or quasi-solid-state battery includes: A positive electrode substrate 10, a carrier for carrying the material of the positive electrode 100; A positive electrode slurry layer 12 is coated on the positive electrode substrate 10, wherein the positive electrode slurry layer 12 comprises: Positive electrode slurry 14 containing a binder, A plurality of positive electrode particles 200 are distributed within the positive electrode slurry 14. Each positive electrode particle 200 comprises a large NCM (nickel cobalt manganese oxide) particle 22, each NCM particle 22 being 3 to 5 microns in size and having a single crystal structure. The positive electrode particles 200 comprise 65 to 70 wt% of the total positive electrode slurry 14. As shown in Figure 1, the NCM macroparticle 22 is an irregular cubic shape, its outer surface covered by numerous Ga-LLZO (gallium-doped lithium lanthanum zirconium oxide) fine particles 24, such as Li₁₂Ga₁₂La₃Zr₂O₁₂) and numerous LATP (Li₁₆Al₇Ti₂-x(PO₄)₃) fine particles 26, forming a composite NCM macroparticle 20. The Ga-LLZO fine particles 24 have a lateral dimension (i.e., the dimension along the spherical surface of the Ga-LLZO fine particles) ranging from 100 to 280 nanometers, while the LATP fine particles 26 have a lateral dimension (i.e., the dimension along the spherical surface of the LATP fine particles) ranging from 50 to 100 nanometers. After sintering, the Ga-LLZO fine particles 24 and LATP fine particles 26 have a shorter longitudinal dimension along the radial direction of the sphere and a wider transverse dimension, while their total volume remains unchanged. The total weight ratio of the Ga-LLZO fine particles 24 to the weight of the single NCM large particle 22 is between 0.5 and 0.8 wt %. The total weight ratio of the LATP fine particles 26 to the weight of the single NCM large particle 22 is between 0.1 and 0.3 wt %. As shown in Figure 3, the Ga-LLZO fine particles 24 are distributed on the NCM large particles 22 in a convex arc shape, with a high center and flat ends. A Ga-LLZO interphase layer 25 forms between the bottom of the Ga-LLZO fine particles 24 and the NCM large particles 22. Its primary function is to guide lithium ions and secondarily to protect the NCM large particles 22. The Ga-LLZO interphase layer 25 is primarily composed of Ga-LLZO and cobalt oxides (the cobalt primarily originates from the outer layer of the NCM large particles 22). Its function is to provide a better channel for lithium ions. The Ga-LLZO interphase layer 25 is an oxygen-deficient layer and an extension layer formed at the interface between the Ga-LLZO fine particles 24 and the NCM large particles 22 during the sintering process. The Ga-LLZO interphase layer 25 facilitates the connection between the NCM macroparticles 22 and the Ga-LLZO fine particles 24, forming a continuous interface. The interphase layer itself also has lithium ion conductivity, but its conductivity is slightly lower than that of the Ga-LLZO fine particles 24. The radial thickness of the Ga-LLZO interphase layer 25 ranges from 2 to 10 nanometers. As shown in Figure 4, the LATP fine particles 26 are distributed on the NCM large particles 22 in a convex arc shape, with a high center and flat ends. A LATP interphase layer 27 forms between the base of the LATP fine particles 26 and the NCM large particles 22. Its primary function is to protect the large NCM particles 22 from electrolyte corrosion. The LATP interphase layer 27 is primarily composed of LATP and cobalt oxides (the cobalt primarily originates from the outer layer of the NCM large particles 22). Its primary function is to protect the large NCM particles 22 from electrolyte corrosion. The LATP interphase layer 27 is an oxygen-deficient layer and an extension layer formed during the sintering process between the LATP fine particles 26 and the NCM large particles 22. This LATP interphase layer 27 facilitates the connection between the NCM large particles 22 and the LATP fine particles 26, forming a continuous interface. The extension layer itself also has ionic conductivity, though slightly less than that of the LATP fine particles 26. The radial thickness of the LATP interphase layer 27 is between 2 and 10 nanometers. In this case, the LATP fine particles 26 partially replace a portion of the Ga-LLZO fine particles 24, reducing negative reactions at the interface with the NCM large particles 22 and lowering the cost of coating the NCM large particles 22. The ionic conductivity of the LATP fine particles 26 is lower than that of the Ga-LLZO fine particles 24. Substituting a portion of the Ga-LLZO fine particles 24 for the LATP fine particles 26 reduces overall production costs without changing the ionic conductivity. In this case, multiple Ga-LLZO fine particles 24 are attached to the outer surface of the large NCM particles 22. Because the Ga-LLZO fine particles 24 have a much higher ion-conducting capacity for lithium ions than the large NCM particles 22 and do not react negatively with lithium ions, the dispersed Ga-LLZO fine particles 24 guide the lithium ions as they pass through the positive electrode 100, thus dispersing their path. This design provides a better lithium ion pathway, significantly increasing overall battery efficiency. The LATP fine particles 26 protect the large NCM particles 22 from electrolyte corrosion and offer greater lithium ion retention and current distribution capabilities. In this case, the Ga-LLZO fine particles 24, the LATP fine particles 26, and the NCM large particles 22 all have a crystalline structure, and therefore have good overall stability and will not be easily released or dissociated, thereby increasing the voltage of the entire battery. As shown in FIG. 1 , the periphery of the composite NCM large particle 20 is coated with CNT 30 (Carbon Nanotube), so the CNT 30 entirely coats the composite NCM large particle 20 , forming the positive electrode particle 200 as a whole. In this case, the CNT 30 is a short-chain CNT 32 with a length between 0.5 μm and 1 μm. The total weight of the CNT 30 accounts for less than 0.25% of the weight of a single large NCM particle 22. As shown in Figure 1, the short-chain CNT 32 is used to bridge the Ga-LLZO fine particles and the NCM large particles 24, and bridge the LATP fine particles 26 and the NCM large particles 22. CNT is a very good conductive material. Carbon nanotubes 30 (CNTs 30) are used to increase electronic conductivity by forming conductive bridges around the various Ga-LLZO fine particles 24 and LATP fine particles 26, allowing electrons to conduct across the composite NCM large particles 20. Because CNTs have extremely high conductivity, electrons can conduct between the various Ga-LLZO fine particles 24 and LATP fine particles 26 and the NCM large particles 22 through the CNTs 30, thereby increasing the overall conductivity of the positive electrode. The CNTs 30 can form bridges at different levels across the Ga-LLZO fine particles 24, the LATP fine particles 26, and the NCM large particles 22. The more CNTs 30 added, the better the conductivity of the entire positive electrode 100. The above structure allows the positive electrode 100 to withstand more lithium ions, thus allowing the entire positive electrode 100 to withstand a higher voltage. For example, for a battery with an original voltage of 4.7V, the voltage can be increased from 4.7V to 4.9V by using the design of this case. The advantage of using carbon nanotubes in this case is that lithium ions are easily stabilized between the nanotubes. Therefore, the cathode paste in this case can stabilize a large number of lithium ions, thereby improving the overall lithium ion conductivity. Electrons can also be easily fixed between the short-chain carbon nanotubes, thereby improving the overall lithium ion conductivity. Furthermore, this extremely high ion conductivity facilitates rapid charging and discharging of the entire battery, and also reduces cobalt usage, lowering overall production costs. The advantage of this design lies in the formation of large NCM particles whose outer surfaces are coated with numerous Ga-LLZO and LATP fine particles. This is because the LATP fine particles have a much higher capacity for accommodating and distributing lithium ions than the large NCM particles, protecting them from electrolyte corrosion and extending the battery's lifespan. Furthermore, the numerous Ga-LLZO fine particles attached to the surfaces of these large NCM particles also possess the ability to accommodate and distribute lithium ions. Therefore, when lithium ions pass through the positive electrode, they are guided by the dispersed Ga-LLZO and LATP fine particles, providing a more dispersed path for the lithium ions. This design also provides a more efficient lithium ion path. This design also coats the large NCM particles coated with Ga-LLZO and LATP fine particles with carbon nanotubes (CNTs). The carbon nanotubes form conductive bridges around the various Ga-LLZO and LATP fine particles, allowing electrons to flow through the composite NCM particles. The architecture of this case can provide stability to the overall positive electrode slurry structure, thereby reducing the use of cobalt. In summary, this invention's user-friendly and thoughtful design meets practical needs. Its specific improvements over existing shortcomings represent a significant breakthrough compared to conventional technologies, offering a genuine improvement in efficacy that is not easily achieved. This invention has not been published or disclosed in domestic or international literature or on the market, thus complying with patent law requirements. The above detailed description is a specific description of one feasible embodiment of the present invention. However, this embodiment is not intended to limit the patent scope of the present invention. Any equivalent implementation or modification that does not depart from the technical spirit of the present invention should be included in the patent scope of this case. 10: Positive electrode substrate 12: positive electrode slurry layer 14: Positive electrode slurry 20: Composite NCM large particles 22: NCM large particles 24:Ga-LLZO fine particles 25:Ga-LLZO interphase layer 26:LATP fine particles 27: LATP interphase layer 30:CNT 32: Short-chain CNT 100: positive electrode 200: Positive electrode particles

Claims

1. A cathode structure of lithium nickel-cobalt-manganese (NCM) cathode particles coated with gallium-doped lithium lanthanum zirconium oxide (Ga-LLZO), lithium aluminum titanium phosphate (LATP), and carbon nanotubes (CNTs), comprising: a cathode substrate, which is a carrier material for supporting a cathode; a cathode slurry layer coated on the cathode substrate, wherein the cathode slurry layer comprises: a cathode slurry containing a binder; a plurality of cathode particles distributed within the cathode slurry, each cathode particle comprising: a large NCM particle; wherein the large NCM particle is of an irregular cubic shape, and its outer surface is composed of numerous Ga-LLZO particles. The material is coated with fine particles and numerous LATP fine particles, forming a composite NCM large particle. The Ga-LLZO fine particles are distributed in a convex arc shape on the NCM large particle, with a high center and gentle ends. A Ga-LLZO mesophase layer is formed between the bottom of the Ga-LLZO fine particles and the NCM large particle, primarily serving to guide lithium ions and secondarily to protect the NCM large particle. The LATP fine particles are also distributed in a convex arc shape on the NCM large particle, with a high center and gentle ends. A LATP mesophase layer is formed between the bottom and the large NCM particles, primarily serving as a protective layer and secondarily as a lithium ion guide. When lithium ions pass through the positive electrode, the dispersed Ga-LLZO fine particles guide the lithium ion pathway. The LATP fine particles prevent the large NCM particles from being corroded by the electrolyte, and they also have higher lithium ion capacity and flow equalization capabilities. The Ga-LLZO fine particles, LATP fine particles, and large NCM particles are all crystalline structures. The composite large NCM particles... The particles are coated with CNTs, which are short-chain CNTs with a length between 0.5 micrometers and 1 micrometer; the NCM large particles are 3 to 5 micrometers in size and have a single crystal structure; the total weight of the Ga-LLZO fine particles relative to the weight of a single NCM large particle is between 0.5 and 0.8 wt%; the total weight of the LATP fine particles relative to the weight of a single NCM large particle is between 0.1 and 0.3 wt%; and the total weight of the CNTs accounts for less than 0.25% of the weight of a single NCM large particle.

2. The cathode structure of NCM cathode particles coated with Ga-LLZO, LATP and CNT as described in claim 1, wherein the radial thickness of the Ga-LLZO mesophase layer is between 2 and 10 nanometers; the Ga-LLZO mesophase layer is formed by Ga-LLZO and cobalt oxides; and its function is to provide a better conduction channel for lithium ions.

3. The cathode structure of NCM cathode particles coated with Ga-LLZO, LATP and CNT as described in claim 1, wherein the radial thickness of the LATP mesophase layer is between 2 and 10 nanometers; the LATP mesophase layer is formed by LATP and cobalt oxides; its main function is to form a protective effect and prevent the large NCM particles from being eroded by the electrolyte.

4. The cathode structure of NCM cathode particles coated with Ga-LLZO, LATP and CNT as described in claim 1, wherein the lateral dimension of the Ga-LLZO fine particles is between 100 and 280 nanometers; and the lateral dimension of the LATP fine particles is between 50 and 100 nanometers.

5. The positive electrode structure of NCM positive electrode particles coated with Ga-LLZO, LATP and CNT as described in claim 1, wherein the short-chain CNT is used to bridge the Ga-LLZO fine particles and the NCM large particles, and to bridge the LATP fine particles and the NCM large particles.

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