Conductive particles with phosphoric acid for positive and negative electrodes

Abstract

A kind of phosphoric acid-based conductive aid particles for positive and negative, which is used in the electrode of solid or quasi-solid battery;The conductive aid particles include: an ion-conducting ceramic particle for guiding lithium ions and dispersing lithium ion channels;An amorphous carbon layer is coated on the outer surface of the ceramic particle, and the amorphous carbon layer itself has good conductivity;The amorphous carbon layer itself has good conductivity, and can inhibit the expansion of the whole ceramic particle;A plurality of graphene sheets are mixed in the amorphous carbon layer, which covers the ceramic particle in the center, and forms a layered structure as a whole;A plurality of first carbon nanotubes are mixed in the amorphous carbon layer, and the whole forms the conductive aid particles;The plurality of first carbon nanotubes are used as bridges between the graphene sheets and the ceramic particle and between different graphene sheets.

Description

Technical Field

[0001] This invention designs battery electrode materials, particularly a phosphoric acid-based conductive particles for positive and negative electrodes. Background Technology

[0002] A battery is mainly formed by placing electrodes (positive and negative electrodes) in an electrolyte. In conventional technology, LLZO material is added to the electrodes to increase ionic conductivity. Because LLZO material has high ionic conductivity for lithium ions, when lithium ions pass through the electrode, the dispersed LLZO particles guide the lithium ions, thus dispersing their pathways. This allows lithium ions to form a uniform channel distribution within the electrode, preventing abnormal accumulation of lithium ions in the electrode slurry and avoiding side reactions with the electrode slurry.

[0003] Because moisture is present during the manufacturing process of this electrode, and LLZO particles are hydrophilic and therefore easily absorb moisture, producing alkaline substances, the outer layer of the LLZO particles must be coated with a protective layer to prevent moisture absorption during electrode manufacturing. Conventional LLZO particles are coated with polydopamine; however, due to the poor electronic conductivity of dopamine itself, when used as an additive in battery plates, it can actually reduce the electronic conductivity of the plates, negatively impacting their performance. Summary of the Invention

[0004] Therefore, the purpose of this invention is to solve the problems of the aforementioned prior art. This invention proposes a phosphoric acid-based conductive particle for both positive and negative electrodes. This particle is coated with an amorphous carbon layer, which suppresses the volume expansion of the entire conductive particle and prevents it from breaking due to excessive expansion. Furthermore, the amorphous carbon layer itself has good conductivity, thus increasing the overall conductivity of the conductive particle. To prevent the amorphous carbon layer from becoming too thick and hindering lithium-ion conduction, the amorphous carbon layer also contains multiple lithium fluoride particles as stepping stones for lithium-ion channels, which facilitates lithium-ion conduction.

[0005] To achieve the above objectives, this invention proposes a phosphoric acid-based conductive particle for positive and negative electrodes, applicable to solid-state or near-solid-state battery electrodes. The conductive particle comprises: an ion-conducting ceramic particle; a pathway for guiding lithium ions and dispersing lithium ions, thus allowing lithium ions to exhibit a uniform channel distribution within the electrode; and an amorphous carbon layer coating the outer surface of the ceramic particle, the amorphous carbon layer itself possessing good conductivity; wherein the radial thickness of the amorphous carbon layer is less than 10 nanometers; and the amorphous carbon layer itself possessing good conductivity. The structure exhibits good conductivity and suppresses the expansion of the entire ceramic particle to avoid excessive volume expansion caused by lithium ions filling the ceramic particle. Multiple graphene sheets are interspersed within the amorphous carbon layer, each graphene sheet having a sheet-like structure that encapsulates the centrally located ceramic particle, forming a layered encapsulation pattern. Multiple first carbon nanotubes are interspersed within the amorphous carbon layer, forming the conductive aid particle. These multiple first carbon nanotubes serve as bridges between the graphene sheets and the ceramic particle, and between different graphene sheets. The structure also includes multiple lithium fluoride particles distributed within the amorphous carbon layer. These lithium fluoride particles act as stepping stones for lithium ion channels, allowing lithium ions to pass through the conductive aid particle, thus facilitating lithium ion conduction. The lithium fluoride particles are distributed in an island-like pattern.

[0006] Based on extensive experience with battery materials, the applicant proposes a novel design: a carbon layer is coated onto the outer surface of the LLZO material, giving it hydrophobic properties and making it less susceptible to moisture penetration. This carbon layer also increases the overall conductivity of the electrode particles. Furthermore, lithium fluoride particles are added within the carbon layer to enhance ion conductivity, and carbon nanotubes and nanoscale amorphous carbon are added to further improve the overall conductivity of the electrode. Therefore, this application presents a novel design that reduces the volume expansion of negative electrode particles, resulting in higher battery performance for current solid-state batteries and further improving battery efficiency.

[0007] The features and advantages of this work will be further explained in the following description; please refer to the accompanying illustrations while reading. Attached Figure Description

[0008] Figure 1 This shows a cross-sectional view of the guiding particles in this case.

[0009] Figure 2 This diagram shows a cross-sectional view of the guiding particles in this case, where the amorphous carbon layer also contains multiple lithium fluoride particles.

[0010] Figure 3 This example demonstrates the application of this case.

[0011] Figure 4 This diagram shows the structure of the composite particles in this case.

[0012] Among them, there are electrode 10, electrode substrate 11, electrode paste 12, electrode paste layer 13, ceramic particles 30, conductive particles 40, second carbon nanotubes 42, composite particles 45, amorphous carbon layer 50, amorphous carbon 52, graphene sheet 54, lithium fluoride particles 55, and first carbon nanotubes 56. Detailed Implementation

[0013] The following is a detailed description of a preferred embodiment of this invention, along with its structural components, effects, and advantages, in conjunction with the accompanying drawings: Please refer to Figures 1 to 4 As shown, this invention presents phosphoric acid-based conductive particles for positive and negative electrodes, primarily used in electrode 10 of solid-state or near-solid-state batteries; as... Figure 3 As shown, the electrode 10 includes: an electrode substrate 11, which is a carrier plate made of material used to support the electrode 10; and an electrode paste layer 13 coated on the electrode substrate 11. The electrode paste layer 13 includes: an electrode paste 12 as a binder and a plurality of conductive particles 40, wherein the total weight of the plurality of conductive particles 40 accounts for 0.1 wt% to 1 wt% of the electrode paste layer. The particle size of the conductive particles 40 in this invention is less than 200 nanometers.

[0014] The structure of each of the guiding particles 40 in this case is described below; for example... Figure 1 As shown, each of the guiding particles 40 comprises: A conductive ceramic particle 30 has a particle size of less than 150 nanometers. The ceramic particle 30 has a high ionic conductivity for lithium ions. Therefore, when lithium ions pass through the electrode, the lithium ion pathway can be dispersed by the guidance of multiple dispersed ceramic particles. This allows the lithium ions to present a uniform channel distribution inside the electrode, avoiding abnormal accumulation of lithium ions in the electrode slurry and preventing side reactions with the electrode slurry.

[0015] The ceramic particles 30 possess lithium-ion conductivity (ionic conductivity greater than 10). - Oxides or phosphates of 3 cm² / s, or oxides or sulfides with garnet or perovskite structures. Among them, the oxides with lithium-ion conductivity include lithium aluminum titanium phosphate (LATP) and lithium aluminum germanium phosphate (LAGP) with NASICON (sodium (Na) super ionic conductor) structure; the phosphates include lithium phosphate (Li3PO4); and the oxides with garnet or perovskite structure include lithium lanthanum zirconium oxide (Li7La3Zr2O). 12 The ceramic particles 30 may be any combination of the above components, such as lithium lanthanum zirconium oxide (LLZO) or lithium lanthanum titanium oxide (LLTO); or lithium germanium phosphorus sulfur (LGPS).

[0016] When the ceramic particles 30 are composed of LLZO, the LLZO material is formed from at least one of LLZO, 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).

[0017] When the ceramic particles 30 are composed of LAGP or LATP, the LAGP or LATP is selected from Li 1+x Al x A 2-x (PO4)3, or Li 1+x+ Al x A 2-x- - zM N_z(PO4)3, where x is between 0.1 and 0.8, y is between 0 and 0.2, and z is between 0 and 0.2; where A is Ge (germanium) or Ti (titanium); and where M is a trivalent cation, such as Sc. 3+ (scandium ion), Y 3+ (Yttrium ions), Ga 3+ (Gallium ions), In3+ (Indium ion), La 3+ (Lanium ion) etc.; where N is a tetravalent cation, such as Zr 4+ (zirconium ions), Si 4+ (silicon ions), Sn 4+ (Tin ions), etc.

[0018] An amorphous carbon layer 50 is coated on the outer surface of the ceramic particle 30. The radial thickness of the amorphous carbon layer 50 is less than 10 nanometers. The amorphous carbon layer 50 itself has good conductivity and can suppress excessive volume expansion caused by lithium ions filling the ceramic particle 30. Therefore, the amorphous carbon layer 50 coating the outer surface of the ceramic particle 30 achieves a protective function and prevents the entire conductive particle 40 from breaking.

[0019] The amorphous carbon layer 50 contains a plurality of amorphous carbons 52, such as: (i) Hard or soft carbon formed by sintering and deesterifying organic resins, or hard or soft carbon formed by sintering and deesterifying organic carbohydrates. (ii) Or it is an amorphous carbon formed by an organic compound under a reducing atmosphere; wherein the organic compound is selected from carbohydrates (such as monosaccharides, disaccharides, oligosaccharides, polysaccharides), water-soluble fibers, or amino acid polymers, etc.; preferably the organic compound is a carbon-containing compound containing at least one element such as nitrogen, fluorine, phosphorus, or sulfur, because after reduction, these elements (i.e., nitrogen, fluorine, phosphorus, or sulfur, etc.) can be incorporated into the carbon to improve the overall electronic conductivity. (iii) Or it is amorphous carbon formed by the dehydration of carbohydrates; (iv) Or it can be formed by dehydrating water-soluble fibers to form amorphous carbon containing multiple carbon skeletons and some functional groups; (v) Or it is an amorphous carbon formed by dehydration of amino acid polymers to form multiple carbon skeletons containing doped elements, either straight or branched. The amorphous carbon-52 series is one or more of the above-mentioned materials.

[0020] Multiple graphene sheets 54 are mixed within the amorphous carbon layer 50. Each graphene sheet 54 is a oligolayer graphene with 2 to 5 layers and a sheet diameter of less than 500 nanometers. Each graphene sheet 54 has a sheet-like structure and encapsulates the ceramic particle 30 at the center, forming a layered encapsulation pattern.

[0021] Multiple first carbon nanotubes 56 are mixed within the amorphous carbon layer 50, and the above structure as a whole forms the conductive particle 40 of this invention. The size of each first carbon nanotube 56 is less than 1 micrometer. The graphene sheet 54 coats the ceramic particle 30, and gaps exist between them. The multiple first carbon nanotubes 56 can be used as bridges between the graphene sheet 54 and the ceramic particle 30, or between different graphene sheets 54, thus improving the conductivity of the entire conductive particle 40. The ceramic particle 30, which coats the amorphous carbon layer 50 containing multiple graphene sheets 54 and multiple first carbon nanotubes 56, forms the corresponding conductive particle 40.

[0022] In a single guiding particle 40, the weight ratio of the ceramic particle 30 to the total weight of the amorphous carbon layer 50 is 99.5:0.5; the weight ratio of the total weight of the graphene sheet 54 to the total weight of the first carbon nanotube 56 is 4:1.

[0023] like Figure 2 As shown, this invention also includes: a plurality of lithium fluoride (LiF) particles 55 distributed within the amorphous carbon layer 50. Because the amorphous carbon layer 50 has a certain thickness, lithium ions will find it difficult to pass through the conductive particles 40 due to the thickness of the amorphous carbon layer 50. The plurality of lithium fluoride particles 55 distributed within the amorphous carbon layer 50 can act as stepping stones for lithium ion channels, thus allowing lithium ions to pass through the conductive particles 40 via the plurality of lithium fluoride particles 55, thereby facilitating lithium ion conduction. The lithium fluoride particles 55 have a particle size of less than 5 nanometers. In a single conductive particle 40 containing the plurality of lithium fluoride particles 55, the weight ratio of the ceramic particles 30 to the total weight of the plurality of lithium fluoride particles 55 is 99.9~99.95:0.1~0.05.

[0024] like Figure 4 As shown, this invention also includes: a plurality of second carbon nanotubes (CNTs) 42 coating the periphery of the conductive particle 40 to form a composite particle 45. The length of the second carbon nanotubes 42 is between 1 micrometer and 3 micrometers. Carbon nanotubes are excellent conductive materials. When multiple second carbon nanotubes 42 are attached to the conductive aid particle 40, they form a shape resembling a ball of yarn. The second carbon nanotubes 42 increase electronic conductivity, allowing electrons to conduct along the conductive aid particle 40. Because carbon nanotubes have extremely high conductivity, lithium ions can pass through them and conduct between the conductive aid particles 40, thus increasing the overall conductivity of the electrode.

[0025] In a single composite particle 45, the total weight of the corresponding plurality of second carbon nanotubes 42 to the weight ratio of the corresponding guiding particle 40 is between 1:99 and 0.2:99.8. The advantage of this design lies in the outer coating of the ceramic particles with an amorphous carbon layer, which suppresses the volume expansion of the entire conductive particle and prevents it from breaking due to excessive expansion. Furthermore, the amorphous carbon layer itself has good conductivity, thus increasing the overall conductivity of the conductive particle. To prevent the amorphous carbon layer from becoming too thick and hindering lithium-ion conduction, it also contains multiple lithium fluoride particles as stepping stones for lithium-ion channels, which facilitates lithium-ion conduction. In conclusion, the human-centered and considerate design of this case is quite in line with actual needs; its specific improvements over existing deficiencies are significant breakthroughs compared to conventional technology, and it does indeed enhance efficacy, which is not easy to achieve; this case has not been publicly disclosed or revealed in domestic or foreign literature and markets, thus complying with the provisions of the Patent Law. 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 that do not depart from the spirit of the present invention should be included in the patent scope of this case.

Claims

1. A phosphoric acid-based conductive particle for use in positive and negative electrodes, characterized in that, Electrodes used in solid-state or solid-state-like batteries; the conductive particles comprise: A ceramic particle that can conduct lithium ions; it is used to guide lithium ions and disperse the lithium ion pathways within the electrode, thus allowing lithium ions to present a uniform channel distribution inside the electrode. An amorphous carbon layer is coated on the outer surface of the ceramic particles, and the amorphous carbon layer itself has good electrical conductivity; It can also suppress the expansion of the entire ceramic particle to avoid excessive volume expansion caused by lithium ions filling the ceramic particle; Multiple graphene sheets are mixed in the amorphous carbon layer, each of which has a sheet-like structure and covers the ceramic particle at the center, forming a layered coating pattern. Multiple first carbon nanotubes are mixed in the amorphous carbon layer to form the conductive particle as a whole; the multiple first carbon nanotubes are used as bridges between the graphene sheets and the ceramic particles and between different graphene sheets.

2. The phosphoric acid-based conductive particles for positive and negative electrodes as described in claim 1, characterized in that, It also includes: multiple lithium fluoride particles distributed within the amorphous carbon layer. These multiple lithium fluoride particles act as stepping stones for lithium ion channels, so lithium ions can pass through the conduction particles via these multiple lithium fluoride particles, thus facilitating lithium ion conduction.

3. The phosphoric acid-based conductive particles for positive and negative electrodes as described in claim 1, characterized in that, The ceramic particles are oxides or phosphates with lithium-ion conductivity, or oxides with garnet or perovskite structures, or sulfides, and are a mixture of the above materials in any proportion; wherein, lithium-ion conductivity refers to an ionic conductivity greater than 10. -3 cm 2 / s.

4. The phosphoric acid-based conductive particles for positive and negative electrodes as described in claim 3, characterized in that, The lithium-ion conductive oxide or lithium-conducting phosphate is selected from lithium titanium aluminum phosphate, lithium germanium aluminum phosphate with NASICON structure; or at least one of the lithium-conducting phosphates.

5. The phosphoric acid-based conductive particles for positive and negative electrodes as described in claim 1, characterized in that, When the ceramic particles are composed of LAGP or LATP, the LAGP or LATP is selected from Li 1+x Al x A 2-x (PO4)3, or Li 1+x+y Al x A 2-x-y-z M y N z (PO4)3, where x is between 0.1 and 0.8, y is between 0 and 0.2, and z is between 0 and 0.2; where A is Ge or Ti; where M is a trivalent cation; and where N is a tetravalent cation.

6. The phosphoric acid-based conductive particles for positive and negative electrodes as described in claim 5, characterized in that, The trivalent cation is selected from Sc 3+ Y 3+ Ga 3+ In 3+ La 3+ .

7. The phosphoric acid-based conductive particles for positive and negative electrodes as described in claim 5, characterized in that, The tetravalent cation is selected from Zr. 4+ Si 4+ Sn 4+ .

8. The phosphoric acid-based conductive particles for positive and negative electrodes as described in claim 2, characterized in that, The size of each lithium fluoride particle is less than 5 nanometers; in a single conductive particle, the weight ratio of the ceramic particle to the total weight of the plurality of lithium fluoride particles is 99.9~99.95:0.1~0.

05.

9. The phosphoric acid-based conductive particles for positive and negative electrodes as described in claim 1, characterized in that, The radial thickness of the amorphous carbon layer is less than 10 nanometers; the particle size of the guiding particle is less than 200 nanometers.

10. The phosphoric acid-based conductive particles for positive and negative electrodes as described in claim 1, characterized in that, The ceramic particles have a particle size of less than 150 nanometers.

11. The phosphoric acid-based conductive particles for positive and negative electrodes as described in claim 1, characterized in that, The amorphous carbon in the amorphous carbon layer is selected from: hard or soft carbon formed by sintering and deesterifying organic resins, or hard or soft carbon formed by sintering and deesterifying organic carbohydrates; or amorphous carbon formed by organic compounds under a reducing atmosphere; or amorphous carbon formed by dehydrating carbohydrates; or amorphous carbon formed by dehydrating water-soluble fibers to form a structure containing multiple carbon skeletons and some functional groups; or amorphous carbon formed by dehydrating amino acid polymers to form a structure containing multiple straight or branched carbon skeletons with doped elements. The amorphous carbon is one or a combination of one or more of the above materials.

12. The phosphoric acid-based conductive particles for positive and negative electrodes as described in claim 11, characterized in that, The organic compound is selected from carbohydrates, which are selected from monosaccharides, disaccharides, oligosaccharides, polysaccharides, water-soluble fibers, or amino acid polymers, etc.

13. The phosphoric acid-based conductive particles for positive and negative electrodes as described in claim 11, characterized in that, The organic compound is a carbon-containing compound that contains at least one element such as nitrogen, fluorine, phosphorus, or sulfur.

14. The phosphoric acid-based conductive particles for positive and negative electrodes as described in claim 1, characterized in that, The graphene sheet consists of 2 to 5 layers of oligolayer graphene, and the graphene sheet has a sheet-like structure with a sheet diameter of less than 500 nanometers.

15. The phosphoric acid-based conductive particles for positive and negative electrodes as described in claim 1, characterized in that, In this amorphous carbon layer, the size of each first carbon nanotube is less than 1 micrometer.

16. The phosphoric acid-based conductive particles for positive and negative electrodes as described in claim 1, characterized in that, In a single guiding particle, the weight ratio of the ceramic particle to the total weight of the amorphous carbon layer is 99.5:0.5; the weight ratio of the total weight of the graphene sheet to the total weight of the first carbon nanotube is 4:

1.

17. The phosphoric acid-based conductive particles for positive and negative electrodes as described in claim 1 or 2, characterized in that, It also includes: multiple second carbon nanotubes coating the periphery of the conductive particle to form a composite particle; when it is attached to the conductive particle, it forms a shape like a ball of yarn; wherein the second carbon nanotubes are used to increase electronic conductivity, so that electrons can be conducted on the conductive particle.

18. The phosphoric acid-based conductive particles for positive and negative electrodes as described in claim 17, characterized in that, The length of the second carbon nanotube is between 1 micrometer and 3 micrometers; and in a single composite particle, the weight ratio of the total weight of the corresponding plurality of second carbon nanotubes to the weight of the corresponding guiding particle is between 1:99 and 0.2:99.8.

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