Negative electrode plate with ceramic composite particles on which a carbon layer is applied

Abstract

A negative electrode plate comprising ceramic composite particles and a carbon layer; the negative electrode plate is used in a solid-state or semi-solid-state battery; the solid-state or semi-solid-state battery comprises a positive electrode, a negative electrode, and a dielectric thin film disposed between the positive and negative electrodes; the negative electrode comprises the negative electrode plate; the negative electrode plate includes: a negative electrode substrate which serves as a carrier for the negative electrode material; a layer of negative electrode mass applied to the negative electrode substrate; the layer of negative electrode mass is formed by a negative electrode mass; the negative electrode mass includes: a plurality of active negative electrode particles which serve to store or release lithium ions; an additive comprising a binder and a dispersant; a variety of conductive agents to increase the electrical conductivity of the negative electrode mass; A multitude of ceramic composite particles guide lithium ions to dispersed lithium ion channels, thereby preventing side reactions between lithium ions and the negative electrode mass due to abnormal deposition of lithium ions in the negative electrode mass. Each ceramic composite particle comprises a ceramic particle and a carbon layer coated on its outer surface. The carbon layer exhibits specific electrical conductivity and prevents excessive volume expansion of the ceramic particle when filled with lithium ions. The binder of the additive serves to adhere the active negative electrode particles, the conductive agent, and the ceramic composite particles. The dispersant of the additive serves to disperse the active negative electrode particles, the conductive agent, and the ceramic composite particles. The active negative electrode particles are dispersed in the negative electrode mass.The conductive agents and the ceramic composite particles are distributed between the active negative electrode particles.

Description

FIELD OF THE INVENTION

[0001] The invention relates to a negative electrode plate of a solid-state battery or a semi-solid-state battery, and more particularly to a negative electrode plate comprising ceramic composite particles having a carbon layer applied thereto. BACKGROUND OF THE INVENTION

[0002] A typical battery consists primarily of positive and negative electrodes in an electrolyte. In the current state of the art, ceramic particles are added to an electrode to increase its ionic conductivity. Since ceramic particles exhibit high lithium ion conductivity, the lithium ion channels in an electrode can be branched along the path of the dispersed ceramic particles as the lithium ions pass through the electrode, resulting in evenly distributed lithium ion channels within the electrode. This prevents side reactions with the electrode mass caused by abnormal deposition of lithium ions within the electrode.

[0003] In conventional negative electrodes, all ceramic particles are made of LATP. Although LATP is hydrophobic, no additional protective layer (such as the carbon layer in this invention) is required. However, LATP has lower ionic conductivity. When the negative electrode is charged and discharged at low voltage, Ti is reduced. 4+ in LATP easy to Ti 3+ and loses its original properties.

[0004] If LLZO and other materials with high ionic electricity transfer capacity are used, they are hydrophilic and can therefore degrade into a negative electrode mass when exposed to solvent (water). The result would be reduced conductivity of the negative electrode mass. SUMMARY OF THE INVENTION

[0005] Accordingly, to remedy the above-mentioned deficiencies in the prior art, the object of the invention is to provide a negative electrode plate comprising ceramic composite particles and a carbon layer. The carbon layer surrounding the ceramic particles protects them, preventing them from reacting with the additives in the negative electrode composition. They are used in the negative electrode composition. The ceramic particles according to the invention can be used not only in prior-art LATPs, but also in LLZOs. Thus, the application possibilities of the ceramic particles are diverse, and the electrical conductivity of the negative electrode is improved.

[0006] To achieve this stated goal, the invention offers negative electrode plates with ceramic composite particles on which a carbon layer is applied.

[0007] The negative electrode comprises the negative electrode plate. The negative electrode plate consists of a negative electrode substrate, which serves as a carrier for the negative electrode material; a layer of negative electrode composition applied to the negative electrode substrate; the negative electrode composition layer consists of a negative electrode composition; the negative electrode composition comprises a plurality of active negative electrode particles, which serve to store or release lithium ions; an additive comprising a binder and a dispersant; and a plurality of conductive agents, which increase the electrical conductivity of the negative electrode composition.a plurality of ceramic composite particles that guide the lithium ions to dispersed lithium ion channels, thus preventing side reactions between the lithium ions and the negative electrode mass due to abnormal deposition of lithium ions in the electrode mass; each of the ceramic composite particles comprises a ceramic particle and a carbon layer applied to its outer surface; wherein the carbon layer has a specific electrical conductivity and serves to prevent excessive volume expansion of the ceramic particle if the ceramic particle is filled with the lithium ions. BRIEF DESCRIPTION OF THE ILLUSTRATIONS

[0008] Fig. shows a schematic view depicting the structure of the negative electrode according to this invention.

[0009] Fig. shows a cross-sectional view showing the structure of the ceramic composite particles according to this invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] Referring to the Fig. The invention provides a negative electrode plate 41 with ceramic composite particles and a carbon layer. The negative electrode plate 41 is used in a solid-state or semi-solid-state battery. The solid-state or semi-solid-state battery comprises a positive electrode 10, a negative electrode 40, and a dielectric thin film 49 between the positive electrode 10 and the negative electrode 40. The negative electrode 40 comprises the negative electrode plate 41.

[0011] According to Fig. The negative electrode plate 41 consists of the following elements: A negative electrode substrate 42 serves as a carrier for the material of the negative electrode 40.

[0012] A negative electrode ground layer 43 is applied to the negative electrode substrate 42. The negative electrode ground layer 43 is formed by a negative electrode ground 44.

[0013] The negative electrode mass 44 includes: A plurality of active negative electrode particles 45, which serve to store or release lithium ions. The active negative electrode particles 45 consist of at least one of the following materials: carbon materials (such as graphite, hard carbons, soft carbons, etc.), Si-C composites, SiOx-C composites, etc. The ratio of the active negative electrode particles 45 to the negative electrode mass layer 43 is between 85 and 97 weight percent. An additive 47 comprises a binder and a dispersant. The binder consists of polymers such as SBR (styrene-butadiene rubber), and the dispersant consists of at least one of the following materials: mineral salts, organic compounds, or polymeric materials. The dispersant can be, for example, CMC (carboxymethylcellulose), besylate (a C6H5SO3-containing salt), ammonium bromide (NH4Br), and TritonX-100. The proportion of additive 47 in the total negative electrode mass layer 43 is between two and six wt.% (wt.%: wt.%). The weight ratio of binder to dispersant is 1:1 / 3 to 3, i.e., the weight ratio of binder to dispersant corresponds to A:B, where B is between 1 / 3 and 3 of A. Several conductive agents 60 are selected from carbon nanotubes, graphene, and amorphous carbons. The weight fraction of the conductive agents 60 in the negative electrode mass layer 43 is 0.5 to 7% by weight. The conductive agents 60 increase the electrical conductivity of the negative electrode mass layer 44 and prevent excessive volume expansion of the negative electrode active particles 45. A plurality of ceramic composite particles 30 guide the lithium ions to dispersed lithium ion channels, thus preventing side reactions between the lithium ions and the negative electrode mass 44 due to abnormal deposition of lithium ions in the negative electrode mass 44. As shown in Fig. As shown, each of the ceramic composite particles 30 consists of a ceramic particle 301 and a carbon layer 302 deposited on its surface. The weight fraction of the ceramic composite particles 30 in the negative electrode mass layer 43 is 0.1 to 2 wt.%. The particle size of each of the ceramic composite particles 30 is less than 200 nm. The active negative electrode particles 45 are distributed in the negative electrode mass 44. The conductive agents 60 and the ceramic composite particles 30 are distributed between the active negative electrode particles 45. The binder of the additive 47 serves to adhere the active negative electrode particles 45, the conductive agent 60, and the ceramic composite particles 30. The dispersant of the additive 47 serves to disperse the active negative electrode particles 45, the conductive agent 60, and the ceramic composite particles 30 to prevent the active negative electrode particles 45, the conductive agent 60, and the ceramic composite particles 30 from aggregating due to gravity and depositing on a bottom surface of the negative electrode mass 44.

[0014] In conventional negative electrodes, all ceramic particles are made of LATP. Although LATP is hydrophobic, no additional protective layer (such as the carbon layer in the invention) is required. However, LATP has lower ionic conductivity. When the negative electrode is charged and discharged at low voltage, the Ti 4+ in LATP easy to Ti 3+and loses its original properties. Therefore, the invention offers an alternative method: LLZO and other materials with higher ionic conductivity are used as solid electrolyte particles for negative electrodes, replacing LATP. However, two problems must be solved: LLZO powder decomposes when mixed with water and has low conductivity. A carbon layer 302 enclosing LLZO can solve these problems. The carbon layer 302 serves to reduce water contact with the surfaces of the ceramic particles 301, since water is a solvent for negative electrode mass. Thus, the decomposition of the ceramic particles due to water contact is reduced. At the same time, the carbon layer 302 promotes electrical transfer within the negative electrode plate 41.

[0015] The ceramic particle 301 consists of at least one of the following materials: a first ceramic oxide or phosphate that conducts lithium ions, and a second oxide with a garnet or perovskite structure. The lithium ion conductivity of the first ceramic oxide or phosphate is greater than 10 -5 cm 2 / s (diffusion coefficient).

[0016] The first ceramic oxide or phosphate can be LATP (lithium aluminum titanium phosphate) with NASICON structure (sodium (Na) superionic conductor), LAGP (lithium aluminum germanium phosphate) or lithiophosphate (Li3PO4). The second oxide can be LLZO (Li7La3Zr2O 12 , lithium lanthanum zirconium oxide) or LLTO (lithium lanthanum titanium oxide). The ceramic particle 301 can be formed by combining the above-mentioned materials in any ratio.

[0017] The ceramic particle 301 may consist of at least one of the following materials: LLZO (Li7La3Zr2O 12), Ga-LLZO (gallium-doped LLZO), Cu-LLZO (copper-doped LLZO), Ta-LLZO (tantalum-doped LLZO), Sr-LLZO (strontium-doped LLZO) and Al-LLZO (aluminum-doped LLZO).

[0018] When the ceramic particle 301 is made of LAGP or LATP, the LAGP is made of Li 1+x Al x Ge 2-x (PO4)3 and Li 1+x+y Al x Ge 2-x-y-z M y N z (PO4)3 is selected; and the LATP is made from Li 1+x Al x Ti 2-x (PO4)3 and Li 1+x+y Al x Ti 2-x-y-z M y N z (PO4)3, where 0.1≤x≤0.8, 0≤y≤0.2, 0≤z≤0.2, M is a trivalent cation and N is a tetravalent cation. M is a trivalent cation (such as scandium cation (Sc 3+ ), yttrium cation (Y 3+ ), gallium cation (Ga 3+ ), indium cation (In 3+ ) or lanthanum cation (La 3+ )) and N is a tetravalent cation (such as zirconium cation (Zr 4+ ), silicon cation (Si 4+) or tin cation (Sn 4+ )).

[0019] The radial thickness of the carbon layer 302 is less than 10 nm. The carbon layer 302 has high electrical conductivity and serves to prevent excessive volume expansion of the ceramic particle 301 when the ceramic particle 301 is filled with lithium ions, thus preventing breakage of the ceramic composite particles 30.

[0020] According to Fig. the carbon layer 302 contains a plurality of amorphous carbons 52. The amorphous carbons 52 consist of at least one of the following materials: (i) Hard carbon or soft carbon obtained by deesterification during sintering of organic resins or organic carbohydrates. (ii) Amorphous carbon, which is formed by the reaction of an organic compound under a reducing atmosphere. The organic compound is selected from carbohydrates (such as monosaccharides, disaccharides, oligosaccharides, or polysaccharides), water-soluble fibers, and amino acid polymers. Preferably, the organic compound is a carbon-containing compound containing at least one of the elements nitrogen, fluorine, phosphorus, and sulfur. Nitrogen, fluorine, phosphorus, and sulfur are doped into the carbon through a reduction reaction, thereby increasing the electrical conductivity of the ceramic composite particle 30. (iii) amorphous carbon, which is formed by dehydration of carbohydrates. (iv) amorphous carbons with carbon skeletons and functional groups formed by dehydration of water-soluble fibers. (v) amorphous carbons with carbon skeletons with straight chains or side chains containing doping elements, formed by dehydration of amino acid polymers.

[0021] The carbon layer 302 further contains a plurality of graphene layers 54. The graphene layers 54 are intermixed within the carbon layer 302. Each of the graphene layers 54 consists of multilayer graphene (FLG) with two to ten graphene layers. The size of each graphene layer 54 is less than 500 nm. Each graphene layer 54 has a layered structure. The graphene layers 54 form a multilayer structure that envelops the outer surface of the ceramic particle 301.

[0022] The carbon layer 302 also contains a plurality of first carbon nanotubes (CNTs) 56. The first carbon nanotubes 56 are incorporated into the carbon layer 302. Each of the first carbon nanotubes 56 is less than 1 µm long. They are distributed in the spaces between the graphene layers 54 and the ceramic particle 301, as well as in the spaces between different graphene layers 54, and serve as bridges between the graphene layers 54 and the ceramic particle 301. This increases the electrical conductivity of the ceramic composite particles 30.

[0023] In each of the ceramic composite particles 30, the ratio of the weight of the ceramic particle 301 to the weight of the carbon layer 302 is 99.5:0.5. The ratio of the total weight of the graphene layers 54 to the total weight of the first carbon nanotubes 56 is 4:1.

[0024] With reference to Fig.The carbon layer 302 also contains a plurality of lithium fluoride (LiF) particles 55. The lithium fluoride particles 55 are mixed into the carbon layer 302. Since the efficiency of the passage of lithium ions through the ceramic composite particles 30 is affected by the thickness of the carbon layer 302, the lithium fluoride particles 55 can be used as bridges to conduct the lithium ions through the ceramic composite particles 30. The lithium fluoride (LiF) particles 55 form a plurality of island-like structures.

[0025] The particle size of each lithium fluoride particle 55 is less than 5 nm. The ratio of the weight of the ceramic particle 301 to the total weight of the lithium fluoride particles 55 for each of the ceramic composite particles 30 is 99.9-99.95:0.1-0.05.

[0026] Thus, a negative electrode plate comprising ceramic composite particles, to which a carbon layer is applied, is provided. The negative electrode plate comprises a negative electrode substrate and a negative electrode mass on the negative electrode substrate. The negative electrode mass is formed by a negative electrode mass and includes a plurality of active negative electrode particles, which serve to store and release lithium ions, an additive including a binder and a dispersant, a plurality of conductive agents, which serve to increase the electrical conductivity of the negative electrode mass, and the ceramic composite particles, which conduct the lithium ions and distribute them in the lithium ion channels. Each of the ceramic composite particles consists of a ceramic particle and a carbon layer, which is applied to the outer surface of the ceramic particle.

[0027] Given the above description of the invention, it is self-evident that it is susceptible to numerous variations. Such variations do not constitute a departure from the spirit of the invention, and all modifications obvious to one skilled in the art are intended to be within the scope of the following claims.

Claims

[1] Negative electrode plate with ceramic composite particles and a carbon layer; the negative electrode plate is used in a solid-state or semi-solid-state battery; the solid-state or semi-solid-state battery includes a positive electrode, a negative electrode, and a dielectric thin film disposed between the positive and negative electrodes; the negative electrode includes the negative electrode plate; the negative electrode plate includes: a negative electrode substrate which serves as a carrier for the negative electrode material; a layer of negative electrode mass applied to the negative electrode substrate; the layer of negative electrode mass is formed by a negative electrode mass; the negative electrode mass includes: a plurality of active negative electrode particles which serve to store or release lithium ions; an additive comprising a binder and a dispersant; a variety of conductive agents to increase the electrical conductivity of the negative electrode mass; A multitude of ceramic composite particles guide lithium ions to dispersed lithium ion channels, thereby preventing side reactions between lithium ions and the negative electrode mass due to abnormal deposition of lithium ions in the negative electrode mass. Each ceramic composite particle comprises a ceramic particle and a carbon layer coated on its outer surface. The carbon layer exhibits specific electrical conductivity and prevents excessive volume expansion of the ceramic particle when filled with lithium ions. The binder of the additive serves to adhere the active negative electrode particles, the conductive agent, and the ceramic composite particles. The dispersant of the additive serves to disperse the active negative electrode particles, the conductive agent, and the ceramic composite particles. The active negative electrode particles are dispersed in the negative electrode mass.The conductive agents and the ceramic composite particles are distributed between the active negative electrode particles. [2] The negative electrode plate according to claim 1, wherein the carbon layer contains a plurality of amorphous carbons. The amorphous carbons consist of at least one of the following materials: (i) hard or soft carbons resulting from deesterification during the sintering of organic resins or organic carbohydrates; (ii) amorphous carbons, which are formed by the reaction of an organic compound under a reducing atmosphere; (iii) amorphous carbons, which are formed by dehydration of carbohydrates; (iv) amorphous carbons with carbon skeletons and functional groups formed by dehydration of water-soluble fibers; and (v) amorphous carbons with carbon skeletons with straight chains or side chains containing doping elements formed by dehydration of amino acid polymers. [3] The negative electrode plate according to claim 2, wherein the organic compound is selected from at least one of the following materials: Monosaccharide, disaccharide, oligosaccharide, polysaccharide, water-soluble fiber and amino acid polymer. [4] The negative electrode plate according to claim 2, wherein the organic compound is a carbonaceous compound containing at least one of nitrogen, fluorine, phosphorus and sulfur. [5] The negative electrode plate according to claim 1, wherein each of the ceramic composite particles has a particle size of less than 200nm and the radial thickness of the carbon layer is less than 10nm. [6] The negative electrode plate according to claim 1, wherein in each of the ceramic composite particles, the ratio of the weight of the ceramic particles to the weight of the carbon layer is 99.5:0.

5. [7] The negative electrode plate according to claim 1, wherein a ratio of the active negative electrode particles to the negative electrode mass layer is between 85 wt% and 97 wt%; a ratio of the additive to the entire negative electrode mass layer is between 2 wt% and 6 wt%; a weight ratio of the binder to the dispersant is 1:1 / 3 to 3; a weight percentage of the conductive agents in the negative electrode mass layer is 0.5 wt% to 7 wt%; a weight percentage of the ceramic composite particles in the negative electrode mass layer is 0.1 wt% to 2 wt%. [8] The negative electrode plate according to claim 1, wherein the ceramic particle is made of at least one of the following materials: “a first ceramic oxide or phosphate capable of conducting lithium ions” and “a second oxide having a garnet or perovskite structure”; and the lithium ion conductivity of the first ceramic oxide or phosphate is higher than 10 -5 cm 2 / s (diffusion coefficient). [9] The negative electrode plate according to claim 8, wherein the second oxide is selected from LLZO and LLTO, wherein LLZO is Li7La3Zr2O 12 (lithium lanthanum zirconium oxide); and LLTO is lithium lanthanum titanium oxide. [10] The negative electrode plate according to claim 1, wherein the ceramic particle is made of LLZO, wherein LLZO is Li7La3Zr2O 12 (lithium lanthanum zirconium oxide). [11] The negative electrode plate according to claim 1, wherein the ceramic particles consist of at least one of the following materials: LLZO (Li7La3Zr2O 12), Ga-LLZO (gallium-doped LLZO), Cu-LLZO (copper-doped LLZO), Ta-LLZO (tantalum-doped LLZO), Sr-LLZO (strontium-doped LLZO) or Al-LLZO (aluminum-doped LLZO). [12] The negative electrode plate according to claim 1, wherein the carbon layer comprises a plurality of graphene layers and the graphene layers are mixed in the carbon layer. [13] The negative electrode plate according to claim 12, wherein each graphene layer is a multilayer graphene (FLG) having two to ten graphene layers and the size of each graphene layer is less than 500nm. [14] The negative electrode plate according to claim 1, wherein the carbon layer further comprises a plurality of first carbon nanotubes (CNTs); and the first carbon nanotubes are mixed into the carbon layer. [15] The negative electrode plate according to claim 1, wherein the carbon layer further comprises a plurality of graphene layer overlays and a plurality of first carbon nanotubes (CNTs); the graphene layer overlays and the first carbon nanotubes are mixed within the carbon layer; and a ratio of a total weight of the graphene layer layers and a total weight of the first carbon nanotubes is 4:

1. [16] The negative electrode plate according to claim 1, wherein the carbon layer further contains a plurality of lithium fluoride (LiF) particles; the lithium fluoride particles are mixed into the carbon layer; the lithium fluoride particles are used as bridges for conducting the lithium ions through the ceramic composite particles; and the lithium fluoride (LiF) particles form a plurality of island-shaped structures. [17] The negative electrode plate according to claim 1, wherein the negative electrode active particles are selected from at least one of the following materials: graphite, hard carbon, soft carbon, Si-C composites, SiOx-C composites, etc.; the binder is selected from SBR; the dispersing agent is selected from at least one of the following materials: mineral salts, organic compounds, polymer materials; the plurality of conductive agents are selected from at least one of the following materials: carbon nanotubes, graphene, and amorphous carbons.

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