Positive electrode plate with ceramic composite particles of phosphoric acid and carbon layer

Abstract

A positive electrode plate comprising ceramic composite particles of phosphoric acid and a carbon layer; the positive 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 positive electrode comprises the positive electrode plate; the positive electrode plate comprises: a positive electrode substrate which serves as a carrier for the positive electrode material; a positive electrode mass layer coated on the positive electrode substrate; the positive electrode mass layer is formed by a positive electrode mass; the positive electrode mass includes: a plurality of positive electrode particles for storing or releasing lithium ions; each of the positive electrode particles is an active material; an adhesive formed from a polymer material; a dispersant; A variety of conductive agents that increase the electrical conductivity of the positive electrode mass; the ceramic composite particles serve to guide the lithium ions to dispersed lithium ion channels, thereby preventing side reactions between the lithium ions and the positive electrode mass due to abnormal deposition of the lithium ions in the positive electrode mass. Each of the ceramic composite particles comprises a ceramic particle and a carbon layer on the outer surface of the ceramic particle. The carbon layer prevents the interaction of oxygen ions on the ceramic particle with a solvent in the positive electrode mass. The carbon layer exhibits specific electrical conductivity and prevents excessive volume expansion of the ceramic particle when filled with lithium ions. The positive electrode particles are distributed within the layer of positive electrode mass. The conductive agents and the ceramic composite particles are distributed between the positive electrode particles.The adhesive bonds the positive electrode particles, the conductive agents, and the ceramic composite particles, and the dispersant serves to disperse the positive electrode particles, the conductive agents, and the ceramic composite particles, thus preventing the positive electrode particles, the conductive agents, and the ceramic composite particles from aggregating and depositing on a bottom surface of the positive electrode mass due to gravity.

Description

FIELD OF THE INVENTION

[0001] The invention relates to a positive electrode plate of a solid-state battery or a semi-solid-state battery, and more particularly to a positive electrode plate having carbon-coated ceramic composite particles formed of phosphoric acid and a carbon layer. BACKGROUND OF THE INVENTION

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

[0003] The surface of the ceramic particles still contains many oxygen ions. Therefore, during electrode manufacturing, when the ceramic particles are added to the positive electrode mass, the positive electrode mass becomes strongly alkaline due to the reaction between the ceramic particles and the solvent in the positive electrode mass. This leads to deterioration of the positive electrode particles in the electrode mass and the electrode mass itself, complicating the manufacturing process and likely resulting in poorer electrochemical properties of the resulting positive electrode plate. Furthermore, the electrical conductivity decreases when ceramic particles are added to the electrode mass.Although this problem can be solved by adding additional conductivity agents, it also leads to a reduction in the proportion of positive electrode particles in the electrode plate, which in turn is detrimental to improving the energy density of the battery. SUMMARY OF THE INVENTION

[0004] In order to remedy the above-mentioned deficiencies of the prior art, the object of the invention is to provide a positive electrode plate comprising ceramic composite particles formed from phosphoric acids and a carbon layer, wherein the carbon layer is applied to the surface of the ceramic particle and thus forms the ceramic composite particle itself.

[0005] The carbon layer protects the ceramic particles from side reactions with the solvent in the positive electrode mass. Furthermore, the use of ceramic composite particles in the positive electrode mass can increase the electrical conductivity of the positive electrode. BRIEF DESCRIPTION OF THE ILLUSTRATIONS Fig. shows schematically the structure of the positive electrode according to the invention. Fig. shows the cross-section of the structure of the ceramic composite particle according to the invention. DETAILED DESCRIPTION OF THE INVENTION

[0006] With reference to the Fig. The invention provides a positive electrode plate 11 with ceramic composite particles formed from phosphoric acids and a carbon layer.

[0007] The positive electrode plate 11 is used in a solid-state or semi-solid-state battery. The solid-state or semi-solid-state battery includes a positive electrode 10, a negative electrode 40, and a dielectric thin film 45 disposed between the positive electrode 10 and the negative electrode 40. The positive electrode 10 includes the positive electrode plate 11.

[0008] The positive electrode plate 11 comprises the following elements: A positive electrode substrate 12 serves as a carrier for the material of the positive electrode 10. A positive electrode ground layer 13 is applied to the positive electrode substrate 12. The positive electrode ground layer 13 is formed by a positive electrode ground 14.

[0009] The positive electrode mass 14 comprises the following: A plurality of positive electrode particles 15 serve to store or release lithium ions. The positive electrode particles 15 consist of LCO particles (LiCoO2) and NCM particles (lithium nickel manganese cobalt oxide). Each of the positive electrode particles 15 is an active material. The weight fraction of the positive electrode particles 15 in the positive electrode mass layer 13 is 92-98 wt.%. An adhesive 17 consists of a polymer material. The polymer material consists of at least one of the following materials: PVDF (polyvinylidene difluoride), PVP (polyvinylpyrrolidone), and PEO (polyoxyethylene). The weight fraction of the adhesive 17 in the positive electrode mass layer 13 is 0.5-3.0 wt.%. A dispersant 19 consists of at least one of the following materials: besylate (a salt with C6H5SO3-), ammonium bromide (NH4Br), and Triton X-100. The weight ratio of the adhesive 17 to the weight of the dispersant 19 is 7:3. The dispersant 19 serves to disperse the materials of the positive electrode mass 14 and thus prevents their aggregation.

[0010] Several conductive materials 21 consist of at least one of the following materials: carbon nanotubes, graphene, and amorphous carbon. The weight fraction of the conductive materials 21 in layer 13 of the positive electrode mass is 0.5 to 2.5 weight percent. The conductive materials 21 increase the electrical conductivity of the positive electrode mass 14.

[0011] 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 positive electrode mass 14 due to abnormal deposition of lithium ions in the positive electrode mass 14. 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 outer surface. The weight fraction of the ceramic composite particles 30 in the positive electrode mass layer 13 is 0.1 to 1.5 weight percent. The particle size of each of the ceramic composite particles 30 is less than 200 nm.

[0012] The positive electrode particles 15 are distributed in the positive electrode mass layer 13. The conductive materials 21 and the ceramic composite particles 30 are dispersed between the positive electrode particles 15. The adhesive 17 serves to adhere the positive electrode particles 15, the conductive materials 21, and the ceramic composite particles 30. The dispersant 19 serves to disperse the positive electrode particles 15, the conductive materials 21, and the ceramic composite particles 30, thereby preventing the positive electrode particles 15, the conductive materials 21, and the ceramic composite particles 30 from aggregating and settling on the underside of the positive electrode mass 14 due to gravity.

[0013] The surfaces of conventional ceramic particles contain many oxygen ions. If these are added to an anode mass during electrode production, the mass reacts with the solvent to produce a strongly alkaline reaction. This leads to the decomposition of the anode particles in the anode mass and the anode mass itself, which complicates the manufacturing process and can impair the electrochemical properties of the produced anode plate. Therefore, according to the invention, the carbon layer 302 on the outer surface of the ceramic particle 301 prevents the interaction of oxygen ions with the solvent of the anode mass 14.

[0014] Although conventional ceramic particles exhibit high ionic conductivity, they are also insulators for electron conduction. This property results in the electrode plate coating with conventional ceramic particles exhibiting higher ionic conductivity than conventional electrode plates, but their electron conductivity (electrical conductivity) is reduced. While this problem can be remedied by adding additional conducting agents, it also leads to a reduction in the proportion of positive electrode particles in the electrode plate, which counteracts an improvement in the battery's energy density. Therefore, according to the invention, the carbon layer 302 not only prevents the ceramic particles 301 from interacting with the solvent in the positive electrode mass 14, but also increases their electron conductivity, thereby solving the above-mentioned problems in the prior art.

[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 above 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 prevents excessive volume expansion of the ceramic particle 301 when filled with lithium ions, thus preventing its breakage.

[0020] As in Fig. As shown, the carbon layer 302 contains a plurality of amorphous carbons 52. The amorphous carbons 52 consist of at least one of the following elements: (i) Hard or soft carbons resulting from deesterification during the sintering of organic resins or organic carbohydrates. (ii) Amorphous carbons 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 carbons, which are 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 including straight chains or side chains containing doping elements formed by dehydration of amino acid polymers.

[0021] The carbon layer 302 further contains several graphene layers 54. These are incorporated into the carbon layer 302. Each graphene layer 54 consists of multilayer graphene (FLG) with two to ten graphene layers. The size of the individual graphene layers 54 is less than 500 nm. Each graphene layer 54 has a layered structure. The graphene layers 54 form a multilayer structure that encloses the outer surface of the ceramic particle 301.

[0022] The carbon layer 302 further contains a plurality of first carbon nanotubes (CNTs) 56. These first carbon nanotubes 56 are incorporated into the carbon layer 302. Each of the first carbon nanotubes 56 is less than 1 µm long. The first carbon nanotubes 56 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 particle 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] As in Fig.As shown, 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 depends on their thickness, the lithium fluoride particles 55 can serve as bridges that conduct the lithium ions through the ceramic composite particles 30. The lithium fluoride particles (LiF) 55 form a plurality of island-like structures.

[0025] The particle size of the 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] A positive electrode plate with ceramic composite particles and a carbon layer thus comprises a positive electrode substrate and a layer of positive electrode mass applied thereon. The layer of positive electrode mass is formed by a positive electrode mass. The positive electrode mass comprises a plurality of positive electrode particles for storing or releasing lithium ions, an adhesive made of a polymer material, a dispersant, a plurality of conductive agents for increasing the electrical conductivity of the positive electrode mass, and the ceramic composite particles for guiding the lithium ions to dispersed lithium ion channels. Each of the ceramic composite particles comprises a ceramic particle and the carbon layer coated on its outer surface.

[0027] Having described the invention above, it is to be understood that it is susceptible to numerous variations. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all modifications obvious to one skilled in the art are intended to be included within the scope of the following claims.

Claims

[1] A positive electrode plate comprising ceramic composite particles of phosphoric acid and a carbon layer; the positive 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 positive electrode comprises the positive electrode plate; the positive electrode plate comprises: a positive electrode substrate which serves as a carrier for the positive electrode material; a positive electrode mass layer coated on the positive electrode substrate; the positive electrode mass layer is formed by a positive electrode mass; the positive electrode mass includes: a plurality of positive electrode particles for storing or releasing lithium ions; each of the positive electrode particles is an active material; an adhesive formed from a polymer material; a dispersant; A variety of conductive agents that increase the electrical conductivity of the positive electrode mass; the ceramic composite particles serve to guide the lithium ions to dispersed lithium ion channels, thereby preventing side reactions between the lithium ions and the positive electrode mass due to abnormal deposition of the lithium ions in the positive electrode mass. Each of the ceramic composite particles comprises a ceramic particle and a carbon layer on the outer surface of the ceramic particle. The carbon layer prevents the interaction of oxygen ions on the ceramic particle with a solvent in the positive electrode mass. The carbon layer exhibits specific electrical conductivity and prevents excessive volume expansion of the ceramic particle when filled with lithium ions. The positive electrode particles are distributed within the layer of positive electrode mass. The conductive agents and the ceramic composite particles are distributed between the positive electrode particles.The adhesive bonds the positive electrode particles, the conductive agents, and the ceramic composite particles, and the dispersant serves to disperse the positive electrode particles, the conductive agents, and the ceramic composite particles, thus preventing the positive electrode particles, the conductive agents, and the ceramic composite particles from aggregating and depositing on a bottom surface of the positive electrode mass due to gravity. [2] The positive 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 positive electrode plate according to claim 2, wherein the organic compound is selected from at least one of the following substances: Monosaccharide, disaccharide, oligosaccharide, polysaccharide, water-soluble fiber and amino acid polymer. [4] The positive electrode plate according to claim 2, wherein the organic compound is a carbon-containing compound containing at least one of nitrogen, fluorine, phosphorus and sulfur. [5] The positive 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 positive 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 positive electrode plate according to claim 1, wherein the weight ratio of the positive electrode particles in the positive electrode mass layer is 92-98 wt%; the weight ratio of the adhesive in the positive electrode slurry layer is 0.5-3.0 wt%; the ratio of the weight of the adhesive to the weight of the dispersant is 7:3; the weight ratio of the conductive substances in the positive electrode mass layer is 0.5 to 2.5 wt%; and the weight ratio of the ceramic composite particles in the positive electrode slurry layer is 0.1 to 1.5 wt%. [8] A positive electrode plate according to claim 1, wherein the ceramic particles consist of at least one of the following oxides: “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 positive electrode plate according to claim 8, wherein the first ceramic oxide or phosphate is selected from LATP (lithium aluminum titanium phosphate) having a NASICON structure (sodium (Na) super ion conductor), LAGP (lithium aluminum germanium phosphate) and lithiophosphate (Li3PO4). [10] The positive electrode plate according to claim 1, wherein the ceramic particle is made of LAGP or LATP, and 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; the LATP is selected 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. [11] A positive electrode plate according to claim 10, wherein M is selected from scandium cation (Sc 3+ ), yttrium cation (Y 3+ ), gallium cation (Ga 3+ ), indium cation (In 3+ ) and lanthanum cation (La 3+ ). [12] The positive electrode plate according to claim 1, wherein the carbon layer further comprises a plurality of graphene layers and the graphene layers are mixed within the carbon layer. [13] The positive electrode plate according to claim 12, wherein each of the graphene layers is a multilayer graphene (FLG) having two to ten graphene layers and the size of each graphene layer is less than 500nm. [14] The positive electrode plate according to claim 1, wherein the carbon layer further contains a plurality of first carbon nanotubes (CNT); the first carbon nanotubes are mixed into the carbon layer. [15] The positive electrode plate according to claim 1, wherein the carbon layer further includes a plurality of graphene layers and a plurality of first carbon nanotubes (CNTs); the graphene layers and the first carbon nanotubes are mixed into the carbon layer; and the ratio of the total weight of the graphene layers to the total weight of the first carbon nanotubes is 4:

1. [16] The positive 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 serve as bridges for guiding the lithium ions through the ceramic composite particles; and the lithium fluoride (LiF) particles form a plurality of island-shaped structures. [17] The positive electrode plate according to claim 1, wherein the positive electrode particles are selected from LCO particles (LiCoO2) and NCM particles (lithium nickel manganese cobalt oxide); the adhesive consists of at least one of the following materials: PVDF (polyvinylidene fluoride), PVP (polyvinylpyrrolidone) and PEO (poly(oxyethylene)); the dispersant consists of at least one of the following materials: besylate, ammonium bromide (NH4Br) and Triton X-100; and the conductive agents consist of at least one of the following materials: carbon nanotubes, graphene and amorphous carbon. [18] A positive electrode plate according to claim 10, wherein N is zirconium cation (Zr 4+ ), silicon cation (Si 4+ ) and tin cation (Sn 4+ ) is selected.

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