NCM electrode particles coated with interphase and nitrogen-containing carbon layers

Abstract

An electrode structure for a solid-state or semi-solid-state battery is provided in which NCM electrode particles coated with an interphase layer and a nitrogen-containing carbon layer are disposed. [Solution] The NCM electrode particles comprise NCM (nickel-cobalt-manganese oxide) particles (15), primary particles (30) that coat the outer surfaces of the NCM particles, an interphase layer (16) that includes a glass phase layer (241) and a plurality of ceramic particles (242), and a nitrogen-containing carbon layer (35) that coats the exterior of the primary particles. Nitrogen-doped carbon molecules in the nitrogen-containing carbon layer aid in the conduction of electrons and lithium ions, modifying the electrical potential of the NCM particles. The nitrogen-containing carbon layer is formed by coating the surfaces of the primary particles with a nitrogen-containing polymer material and calcining the material in an inert atmosphere. Conjugated bonds are formed between the carbon and nitrogen, modifying the energy band structure, reducing the energy required for electrons to transition to the conduction band, and improving overall electronic conductivity.

Description

[Technical Field]

[0001] The present invention relates to an electrode particle, and more particularly to an NCM electrode particle coated with an interphase layer and a nitrogen-contained carbon layer. [Background technology]

[0002] Batteries are typically formed by adding positive and negative electrodes to an electrolyte. The positive electrode is made by mixing and stirring multiple positive conductive units (positive electrode materials, such as lithium cobalt oxide) to form a slurry. Typically, the positive conductive units are first mixed and stirred with the conductive slurry before being applied to electrode plates and assembled into a battery. Because multiple positive conductive units (positive electrode materials) are connected via the conductive slurry, the conductive slurry must have conductive auxiliary or conductive properties to enable the transfer of free electrons between different positive conductive units and prevent excessive energy consumption due to internal resistance, thereby achieving efficient conductivity. Therefore, when preparing the slurry, it is necessary to consider using specific conductive materials to adjust the conductivity of the slurry. Summary of the Invention [Problem to be solved by the invention]

[0003] Typically, multiple positive electrode particles are packed into a positive electrode slurry to enhance electrical conductivity. The positive electrode particle material may be selected from NCM (nickel-cobalt-lithium manganese oxide), LMFP (manganese-iron-lithium phosphate), etc., or a mixture thereof, and the positive electrode particles are distributed within the positive electrode slurry. However, in conventional technologies, side reactions are likely to occur at the interface of the positive electrode particles, shortening the lifespan of the positive electrode and resulting in low electronic conductivity and overall battery efficiency.

[0004] Therefore, the present invention provides an NCM electrode particle coated with a novel interphase layer and nitrogen-containing carbon layer, which covers the outer surface of the positive electrode particle with an interphase layer to protect the positive electrode particle from decomposition during sintering, and further covers the outside of the interphase layer with a carbon layer to enhance electrical conductivity, thereby solving the above-mentioned deficiencies of the prior art.

[0005] The present invention has been made to solve the above-mentioned problems of the prior art. That is, the object of the present invention is to provide an NCM electrode particle coated with an interphase layer and a nitrogen-containing carbon layer. [Means for solving the problem]

[0006] To achieve the above objective, one embodiment of the present invention provides an NCM electrode particle coated with an interphase layer and a nitrogen-containing carbon layer. By coating the outer surface of the NCM particle with an interphase layer, the risk of the NCM particle being decomposed by the inert gas used in the process of manufacturing the NCM electrode particle is reduced, and the interphase layer can also enhance the ion guiding effect. Further coating the outside of the interphase layer with a nitrogen-containing carbon layer can further increase the conductivity of the entire composite NCM particle. [Effects of the Invention]

[0007] At least the following points will become clear from the description and drawings to be described later. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic cross-sectional view showing the structure of an NCM electrode particle according to one embodiment of the present invention. [Figure 2] 1 is a schematic enlarged view showing the structure of an NCM electrode particle according to an embodiment of the present invention; [Figure 3] 1 is a schematic diagram illustrating a nitrogen-containing carbon layer according to an embodiment of the present invention; [Figure 4] 1 shows an example of an NCM electrode particle coated with an interphase layer and a nitrogen-containing carbon layer according to the present invention. [Figure 5]1 is a schematic diagram illustrating a secondary NCM electrode particle according to an embodiment of the present invention; DETAILED DESCRIPTION OF THE INVENTION

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

[0010] First, an example of a specific embodiment of the NCM electrode particle coated with an interphase layer and a nitrogen-containing carbon layer of the present invention will be described with reference to FIGS.

[0011] The NCM electrode particles 100 coated with an interphase layer and a nitrogen-containing carbon layer according to the present invention are primarily used in electrodes 10 for solid-state or semi-solid-state batteries. In practical applications, a plurality of NCM electrode particles 100 are disposed within the electrode 10, which serves as a positive electrode. The particle size of the NCM electrode particles 100 is less than 10 μm. As shown in FIG. 4, the electrode 10 includes an electrode substrate 11 for supporting the electrode 10 materials and an electrode slurry layer 13 applied to the electrode substrate 11. The electrode slurry layer 13 includes an electrode slurry 12 as a binder and a plurality of the NCM electrode particles 100. The weight percentage of the plurality of NCM electrode particles 100 in the electrode slurry layer 13 ranges from 80 wt% to 98 wt%.

[0012] Next, the configuration of the NCM electrode particle 100 of the present invention will be described. The NCM electrode particle 100 mainly comprises the following components (see FIG. 1).

[0013] The NCM (lithium nickel manganese cobalt oxide) particles 15 have a single crystal structure, and NCM is a ternary oxide. The D50 particle size (mass-median-diameter, MMD, mass median diameter of particle size distribution) of the NCM particles 15 is in the range of 3 μm to 5 μm, and the D90 particle size does not exceed 10 μm.

[0014] The interphase layer 16 covers the outer surface of the NCM particle 15 , and the NCM particle 15 having the interphase layer 16 forms a primary particle 30 .

[0015] The interphase layer 16 includes a glass phase layer 241 and a plurality of ceramic particles 242 distributed in the glass phase layer 241. The interphase layer 16 is used to protect the NCM particles 15 and enhance the lithium ion guiding effect. Each of the ceramic particles 242 has a particle size of less than 100 nm. The radial thickness of the glass phase layer 241 is in the range of 50 nm to 1 μm. The radial thickness of the interphase layer 16 is in the range of 50 nm to 1 μm. In the interphase layer 16, the weight ratio of the total weight of the plurality of ceramic particles 242 to the total weight of the glass phase layer 241 is in the range of 10:1:10.

[0016] The glass phase layer 241 is made of an amorphous oxide, and the amorphous oxide is subjected to a heat treatment to increase its lithium ion conductivity to 10 -5 The amorphous oxide is an oxide of lithium and an element of group IIIA, IVA, or VA, or an amorphous oxide-based solid electrolyte. The oxide of lithium and an element of group IIIA, IVA, or VA is, for example, LiO-RO xwhere x=1 to 3, and R is selected from boron (B), aluminum (Al), silicon (Si), germanium (Ge), phosphorus (P), and arsenic (As). The amorphous oxide-based solid electrolyte is an amorphous perovskite-based solid electrolyte (Li-La-Ti-O, LLTO), a garnet-based solid electrolyte (Li7La3Zr2O 12 At least one material is selected from the group consisting of lithium phosphorus oxynitride (LLZO), lithium phosphorus oxynitride (LiPON), and lithium titanium aluminum phosphate (LATP). The crystalline structure of the glass phase layer 241 does not have a specific morphology, and the glass phase layer 241 is a continuous thin film layer that covers the outer surface of the NCM particle 15.

[0017] The ceramic particles 242 are oxides having a protective effect or ceramic oxides capable of improving lithium ion conductivity. The oxides having a protective effect are at least one of aluminum oxide, silicon oxide, etc. The ceramic oxides capable of improving lithium ion conductivity are solid electrolyte materials.

[0018] The solid electrolyte material has a lithium ion conducting capacity (ionic conductivity is 10 -5 cm 2 The oxide or phosphate having a diffusion coefficient of more than 1 / s, or an oxide having a garnet or perovskite structure. The oxide or phosphate having lithium ion conducting ability is, for example, lithium aluminum titanium phosphate (LATP) having a NASICON (sodium (Na) super ionic conductor) structure, lithium aluminum germanium phosphate (LAGP), or a phosphate having lithium conducting ability, such as lithium phosphate (Li3PO4). The oxide having a garnet or perovskite structure is, for example, lithium lanthanum zirconium oxide (Li7La3Zr2O12 The ceramic particles 242 may be a combination of the above components in any ratio.

[0019] The NCM electrode particles 100 are formed by sintering in an inert atmosphere. Nickel-cobalt-manganese lithium oxide is easily decomposed in an inert atmosphere, leading to easy degradation and unstable battery performance. However, the interphase layer 16 of the present invention has low sensitivity to oxygen and can maintain its structural stability even in an inert atmosphere. Therefore, the interphase layer 16 can protect the inner NCM particles 15, making them less susceptible to the effects of the inert atmosphere.

[0020] The nitrogen-containing carbon layer 35 coats the exterior of the primary particle 30, and the NCM particle 15 having the interphase layer 16 and the nitrogen-containing carbon layer 35 forms the NCM electrode particle 100 (see FIG. 1 ). The radial thickness of the nitrogen-containing carbon layer 35 is ≦0.2 μm. The nitrogen-containing carbon layer 35 is used to increase the electrical conductivity of the entire NCM electrode particle 100. As shown in FIG. 3 , the nitrogen-containing carbon layer 35 is composed of highly-ordered carbon structures containing multiple carbon-nitrogen double bonds (C═N). The highly-ordered carbon structures containing carbon-nitrogen double bonds are bonded to lone-pair-containing oxygen ions on the surface of the interphase layer 16 by hydrogen bonding, thereby forming the nitrogen-containing carbon layer 35 that coats the exterior of the primary particle 30.

[0021] The nitrogen-doped carbon molecules in the nitrogen-containing carbon layer 35 aid in the conduction of electrons and lithium ions, modifying the potential of the NCM particles 15 and improving overall battery performance. The nitrogen-containing carbon layer 35 coats the outer surfaces of the primary particles 30. The nitrogen-containing carbon layer 35 is formed by coating the surfaces of the primary particles 30 with a nitrogen-containing polymer material and then calcining the coated surface in an inert atmosphere. The nitrogen-containing polymer material is, for example, polydopamine or a material that generates carbon-nitrogen unsaturated conjugated bonds (C=N bonds) after calcination. The formation of conjugated bonds between carbon and nitrogen modifies the energy band structure, reducing the energy required for electrons to transition to the conduction band and improving overall electronic conductivity.

[0022] 6, the present invention further comprises a plurality of carbon nanotubes (CNTs) 40 and a plurality of nanometric amorphous carbons 45 coating the outer surface of the NCM electrode particle 100, forming a secondary NCM electrode particle 50. The size of each carbon nanotube 40 ranges from 200 nm to 500 nm, and the size of each nanometric amorphous carbon 45 ranges from 10 nm to 40 nm. The nanometric amorphous carbon 45 is, for example, amorphous carbon with a super P conductive agent.

[0023] The weight ratio of "the total weight of the plurality of carbon nanotubes 40 and the plurality of nanometric amorphous carbons 45" to the total weight of the NCM particles 15 is in the range of 0.2-2:99.8-98.

[0024] Carbon nanotubes are used to increase the electrical conductivity of electrons and enable electron conduction on each of the NCM electrode particles 100. Each of the carbon nanotubes 30 is randomly distributed on the surface of the corresponding NCM electrode particle 100. Carbon nanotubes have extremely high electrical conductivity, and the carbon nanotubes 40 enable electron conduction between different NCM electrode particles 100, thereby increasing the electrical conductivity of the entire positive electrode 100.

[0025] The nanometer amorphous carbons 45 and the carbon nanotubes 40 are both conductive materials. Each nanometer amorphous carbon 45 has a particle shape, and each carbon nanotube 40 has an elongated shape. The nanometer amorphous carbons 45 fill the gaps formed between the carbon nanotubes 40 that are intertwined vertically and horizontally on the NCM electrode particle 100. The nanometer amorphous carbons 45 bridge each other, conducting charges between different carbon nanotubes 40 and further increasing current transmission efficiency.

[0026] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means devised in different embodiments are also included in the technical scope of the present invention. [Explanation of symbols]

[0027] 10 electrodes 11 Electrode substrate 12 Electrode slurry 13 Electrode slurry layer 15 NCM particles 16 Interphase layer 30 Primary particles 35 Nitrogen-containing carbon layer 40 Carbon nanotubes 45 nanometer amorphous carbon 50 Secondary NCM electrode particles 100 NCM electrode particles 241 Glass phase layer 242 Ceramic particles

Claims

1. 1. An NCM electrode particle coated with an interphase layer and a nitrogen-containing carbon layer for use in an electrode of a solid-state or semi-solid battery, the NCM electrode particle comprising: NCM (lithium nickel manganese cobalt oxide) particles having a single crystal structure; an interphase layer covering the outer surface of the NCM particle, the NCM particle having the interphase layer forming a primary particle; the interphase layer includes a glass phase layer and a plurality of ceramic particles distributed in the glass phase layer, the interphase layer being used to protect the NCM particles and enhance a lithium ion guiding effect; An NCM electrode particle coated with an interphase layer and a nitrogen-containing carbon layer, characterized in that the NCM electrode particle is formed from NCM particles having the interphase layer and the nitrogen-containing carbon layer, and the nitrogen-containing carbon layer is a nitrogen-containing carbon layer that coats the exterior of the primary particle, and the nitrogen-containing carbon layer is used to increase the conductivity of the NCM electrode particle.

2. 2. The NCM electrode particle coated with an interphase layer and a nitrogen-containing carbon layer according to claim 1, wherein the nitrogen-containing carbon layer is composed of a highly ordered carbon structure containing a carbon-nitrogen double bond (C=N), and the highly ordered carbon structure containing the carbon-nitrogen double bond is bonded to lone-pair-containing oxygen ions on the surface of the interphase layer by a hydrogen bonding force, thereby forming the nitrogen-containing carbon layer.

3. 2. The NCM electrode particle coated with an interphase layer and a nitrogen-containing carbon layer according to claim 1, wherein the D50 particle size of the NCM particles is in the range of 3 μm to 5 μm, the particle size of each of the ceramic particles is less than 100 nm, the radial thickness of the glass phase layer is in the range of 50 nm to 1 μm, and the weight ratio of the total weight of the plurality of ceramic particles to the total weight of the glass phase layer is in the range of 10:1:

10.

4. The glass phase layer is an amorphous oxide, and the amorphous oxide is subjected to a heat treatment to have a lithium ion conductivity of 10 -５ 2. The NCM electrode particle coated with an interphase layer and a nitrogen-containing carbon layer according to claim 1, characterized in that the glass phase layer is an amorphous oxide having a viscosity of more than 1000 S / cm, the crystalline structure of the glass phase layer does not have a specific morphology, and the glass phase layer is a continuous thin film layer covering the outer surface of the NCM particle.

5. 5. The NCM electrode particle coated with an interphase layer and a nitrogen-containing carbon layer according to claim 4, wherein the amorphous oxide is an oxide of lithium and an element of Group IIIA, IVA, or VA.

6. The amorphous oxide is Li ２ O-RO ｘ 6. The NCM electrode particle coated with an interphase layer and a nitrogen-containing carbon layer according to claim 5, wherein x=1-3 and R is selected from boron (B), aluminum (Al), silicon (Si), germanium (Ge), phosphorus (P), and arsenic (As).

7. 2. The NCM electrode particle coated with an interphase layer and a nitrogen-containing carbon layer according to claim 1, wherein the ceramic particle is an oxide having a protective effect or a ceramic oxide capable of improving lithium ion conductivity.

8. The NCM electrode particle coated with an interphase layer and a nitrogen-containing carbon layer according to claim 7, characterized in that the oxide having a protective effect is at least one selected from the group consisting of aluminum oxide, silicon oxide, etc.

9. The NCM electrode particle coated with an interphase layer and a nitrogen-containing carbon layer according to claim 7, wherein the oxide ceramic capable of improving lithium ion conductivity is a solid electrolyte material.

10. The solid electrolyte material is an oxide or phosphate-based material having lithium ion conductivity, or an oxide having a garnet or perovskite structure, and the ionic conductivity of the oxide or phosphate-based material having lithium ion conductivity is 10 -５ cm ２ 10. The NCM electrode particle coated with an interphase layer and a nitrogen-containing carbon layer according to claim 9, characterized in that the NCM electrode particle has a diffusion coefficient of more than 1 / s.

11. 11. The NCM electrode particle coated with an interphase layer and a nitrogen-containing carbon layer according to claim 10, wherein the oxide or phosphate having lithium ion conductivity is at least one selected from the group consisting of lithium aluminum titanium phosphate (LATP) and lithium aluminum germanium phosphate (LAGP) having a NASICON (sodium (Na) super ionic conductor) structure.

12. The oxide having a garnet or perovskite structure is lithium lanthanum zirconium oxide (Li ７ La ３ Zr ２ O １２ 11. The NCM electrode particle coated with an interphase layer and a nitrogen-containing carbon layer according to claim 10, characterized in that at least one of the interphase layer and the nitrogen-containing carbon layer is selected from the group consisting of lithium lanthanum zirconium oxide (LLZO) and lithium lanthanum titanium oxide (LLTO).

13. 2. The NCM electrode particle coated with an interphase layer and a nitrogen-containing carbon layer according to claim 1, wherein the radial thickness of the nitrogen-containing carbon layer is ≦0.2 μm.

14. 2. The NCM electrode particle coated with an interphase layer and a nitrogen-containing carbon layer according to claim 1, characterized in that the nitrogen-containing polymer material is selected from polydopamine or a material that generates a carbon-nitrogen unsaturated conjugated bond after calcination.

15. 2. The NCM electrode particle coated with an interphase layer and a nitrogen-containing carbon layer according to claim 1, further comprising a plurality of carbon nanotubes (CNTs) and a plurality of nanometer amorphous carbons coating the outer surface of the NCM electrode particle.

16. The NCM electrode particle coated with an interphase layer and a nitrogen-containing carbon layer according to claim 15, wherein the size of the carbon nanotubes is in the range of 200 nm to 500 nm, and the size of the nanometer amorphous carbon is in the range of 10 nm to 40 nm.

17. The NCM electrode particle coated with an interphase layer and a nitrogen-containing carbon layer according to claim 15, wherein the weight ratio of "the total weight of the plurality of carbon nanotubes and the nanometer amorphous carbon" to the total weight of the NCM particle is in the range of 0.2-2:99.8-98.

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