Cathode electrode sheet and preparation method therefor

Abstract

A cathode electrode sheet, a lithium ion battery comprising the cathode electrode sheet, and an electric device comprising the lithium ion battery. The cathode electrode sheet comprises: a current collector; and an active material layer, wherein the active material layer is arranged on at least one surface of the current collector; the active material layer comprises a cathode active material and an inorganic single-ion conductor material, or the active material layer comprises a cathode active material coated with an inorganic single-ion conductor material on the surface; the ionic conductivity of the inorganic single-ion conductor material is greater than or equal to 3×10-3 S / cm; and the coating weight of the active material layer is 24 mg / cm2 to 43 mg / cm2.

Description

A cathode electrode and a method for preparing the same

[0001] Cross-references

[0002] This application refers to Chinese patent application No. 202310923551.4 filed on July 26, 2023, entitled “A cathode plate, a lithium-ion battery and an electrical device”, which is incorporated into this application in its entirety by reference. Technical Field

[0003] The present application relates to the technical field of battery material preparation, and in particular to a cathode electrode and a preparation method thereof. Background Art

[0004] Among the numerous battery products, lithium-ion batteries have attracted close attention due to their advantages such as light weight, small size, high operating voltage, high energy density, high output power, high charging efficiency, no memory effect, and long cycle life. They have been widely used in mobile phones, laptop computers and other fields.

[0005] In recent years, due to the continuous improvement in the performance of mobile devices and communication equipment, higher requirements have been placed on the energy density, cycle life, and high current output and input performance of lithium-ion batteries. Ultra-high nickel cathode active materials have been widely used in lithium-ion batteries. Compared with other cathode materials, ultra-high nickel cathode active materials have the advantage of higher theoretical reversible capacity (>200mAh / g). In addition, high energy density lithium-ion battery systems also require thicker electrode plates, but thick electrode plates increase the lithium ion transmission distance, resulting in insufficient ion transmission channels and deteriorating kinetics.

[0006] SUMMARY OF THE INVENTION

[0007] In response to the above-mentioned existing technical problems, the present application provides a cathode electrode and a method for preparing the same. The preparation method of the cathode electrode of the present application is simple, reproducible, low-cost, and environmentally friendly, and the lithium-ion battery using the cathode electrode has higher dynamic performance and energy density.

[0008] In a first aspect, the present application provides a cathode electrode, comprising:

[0009] a current collector; and

[0010] active material layer,

[0011] The active material layer is provided on at least one surface of the current collector,

[0012] The active material layer includes a cathode active material and an inorganic single ion conductor material, or the active material layer includes a cathode active material coated with an inorganic single ion conductor material.

[0013] The ionic conductivity of inorganic single ion conductor materials is ≥3×10 -3 S / cm;

[0014] The coating weight of the active material layer was 24 mg / cm 2 -43mg / cm 2 .

[0015] The ionic conductivity of the inorganic single-ion conductor material described in this application is tested using the following method: at 25°C, the powder of the inorganic single-ion conductor material is pressed into a sheet in a mold under a certain pressure (20 MPa) to serve as the electrolyte. The electrolyte is placed between blocking electrodes (the blocking electrodes are formed by magnetron sputtering gold treatment). The blocking electrodes are tested by electrochemical impedance spectroscopy (EIS), and the ionic conductivity σ of the inorganic single-ion conductor material is calculated according to the formula σ = d / SR. Here, d is the thickness of the electrolyte; S is the effective contact area between the electrode and the electrolyte; and R is the intrinsic resistance of the electrolyte.

[0016] The cathode plate of this application is a thick film cathode plate design. As used herein, the term "thick film cathode plate" refers to a coating weight of the active material layer of 24-43 mg / cm 2 By introducing an inorganic single ion conductor material with high ionic conductivity into the cathode active material, the thick film electrode of the present application can provide continuous / multiple ion transport channels.

[0017] In some embodiments, the inorganic single ion conductor material comprises lithium lanthanum titanate (Li 0.33 La 0.56 TiO3, LLTO), lithium aluminum titanium phosphate (Li 1.3 Al 0.3 Ti 1.7 (PO4)3, LATP), lithium germanium aluminum phosphate (Li 1.5 Al 0.5 Ge 1.5 (PO4)3, LAGP), lithium germanium phosphorus sulfur (Li 10 GeP2S 12 , LGPS), one or more of antiperovskite materials (Li3OX), glassy sulfides (yLi2S·(100-y)P2S5) and halogen sulfides (Li6PS5X), wherein 0<y<100, and X is selected from Cl, Br or I.

[0018] Among the above optional materials, lithium lanthanum titanium oxide (Li 0.33 La 0.56 The ionic conductivity of TiO3, LLTO) is about 3×10 -3 S / cm; Lithium aluminum titanium phosphate (Li 1.3 Al 0.3 Ti 1.7The ionic conductivity of (PO4)3, LATP) is about 3×10 -3 S / cm; Lithium Germanium Aluminum Phosphate (Li 1.5 Al 0.5 Ge 1.5 The ionic conductivity of (PO4)3, LAGP) is about 6×10 -3 S / cm; Lithium Germanium Phosphorus Sulfur (Li 10 GeP2S 12 The ionic conductivity of LGPS is about 4×10 -3 S / cm); the ionic conductivity of antiperovskite materials (Li3OX, where X = Cl, Br or I) is about 4×10 -3 S / cm; the ionic conductivity of glassy sulfide (yLi2S·(100-y)P2S5) is about 5×10 -3 S / cm); and the ionic conductivity of halogen sulfide (Li6PS5X, where X is Cl, Br or I) is about 5×10 -3 S / cm.

[0019] The inorganic single-ion conductor material of the present application is suitable for physical mixing with all cathode active materials known in the prior art or for coating all cathode active materials known in the prior art. Cathode active materials known in the prior art include, but are not limited to, LiCoO2, lithium-nickel-cobalt-manganese compounds (abbreviated as NCM), lithium-nickel-cobalt-aluminum compounds (NCA), olivine-structured compounds (including lithium iron phosphate, lithium iron manganese phosphate, etc.), and spinel-structured compounds (including lithium manganese oxide, etc.). The cathode active material may also include a mixture of two or more of the above compounds.

[0020] Alternatively, in some embodiments, the cathode active material of the present application may include a LiNi m Co n Mn b One or more of a ternary material of O2 and a doping and coating material thereof, wherein m+n+b=1, and 0.96≤m≤0.995.

[0021] In some embodiments, the glassy sulfide may include 25Li2S·75P2S5.

[0022] In some embodiments, the inorganic single ion conductor material may be doped with elements such as Ga, Ta, W, or Al. Those skilled in the art will appreciate that the inorganic single ion conductor material may be doped with one or more of the elements Ga, Ta, W, and Al, as long as such doping is expected to further enhance its ionic conductivity.

[0023] For example, when the inorganic single ion conductor material LLTO is doped with Ga, its ionic conductivity will increase to 3.5×10 -3 .

[0024] In some embodiments, the inorganic single-ion conductor material is a nanoparticle, preferably 20-500 nm, or 50-200 nm; or the inorganic single-ion conductor material is a nanowire, preferably 5-200 nm, or 10-50 nm. Nanoparticles are more conducive to lithium ion conduction and improve the battery's kinetic performance.

[0025] In some embodiments, the mass of the inorganic single ion conductor material may account for 0.1-5%, optionally 0.5-5%, of the total mass of the inorganic single ion conductor material and the cathode active material.

[0026] For example, when the inorganic single ion conductor material of the present application is LLTO and the cathode active material is LiNi 0.96 Co 0.02 Mn 0.02 When O2, LLTO / (LLTO+LiNi 0.96 Co 0.02 Mn 0.02 The mass ratio of O2) can be 0.1-5%, optionally 0.5-5%.

[0027] In some embodiments, the active material layer comprises a physical mixture of a cathode active material and an inorganic single ion conductor material. In some alternative embodiments, the active material layer comprises a cathode active material having a surface coated with an inorganic single ion conductor material.

[0028] In the second aspect, the present application provides a method for preparing a cathode active material that introduces an inorganic single-ion conductor material, the method comprising first dispersing a precursor of the inorganic single-ion conductor material in an organic solvent, and then mixing it with the cathode active material to obtain a cathode active material that introduces the inorganic single-ion conductor material; and the present application also provides a method for preparing a cathode active material whose surface is coated with an inorganic single-ion conductor material with simple operation, the method comprising first dispersing the cathode active material in an organic solvent, and then mixing it with a precursor of the inorganic single-ion conductor material, and finally drying and sintering to obtain a cathode active material whose surface is coated with an inorganic single-ion conductor material.

[0029] In some embodiments, the organic solvent can be selected from one or more of ethanol, ammonia, ethylenediamine, 1,2-ethanedithiol, ethylene glycol, methanol, cyclohexane, carbon tetrachloride, chloroform, dichloromethane, dimethylformamide, dimethylacetamide and N-methylpyrrolidone, or a mixture thereof, and anhydrous ethanol and N-methylpyrrolidone can be selected.

[0030] The present invention discloses a method for preparing a cathode active material having an inorganic single-ion conductor material coated on its surface, comprising first dispersing the cathode active material in a suitable organic solvent, then mixing it with a precursor of the inorganic single-ion conductor material for more uniform liquid-phase coating, and finally sintering the material at a suitable temperature to obtain the cathode active material having the inorganic single-ion conductor material coated on its surface. The present invention discloses a method for preparing a cathode active material having an inorganic single-ion conductor material coated on its surface, utilizing liquid-phase coating and sintering, which can significantly improve the uniformity of the coating of the inorganic single-ion conductor material.

[0031] In a third aspect, the present application provides a method for preparing a cathode electrode, comprising:

[0032] The cathode active material introduced with inorganic single ion conductor material or the cathode active material with inorganic single ion conductor material coated on the surface according to the second aspect of the present application, a binder and a conductive agent are dispersed in an organic solvent to form a slurry, and the slurry is coated on a current collector and dried to obtain a cathode electrode.

[0033] In some embodiments, the binder can be selected from at least one of the following groups: carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, polyvinylidene fluoride, polytetrafluoroethylene, polyethylene, polypropylene, polybutadiene, butyl rubber, fluororubber, polyoxyethylene, polyvinyl alcohol, polyacrylic acid and its salts, polyvinyl pyrrolidone, polyepichlorohydrin, polyphosphazene, polyacrylonitrile, polystyrene, polyvinyl pyridine, chlorosulfonated polyethylene, latex, polyester resin, acryl resin, phenolic resin, epoxy resin, polyurethane, polyalkene, copolymers of propylene and olefins having 2-8 carbon atoms, copolymers of (meth)acrylic acid and alkyl (meth)acrylates, polystyrene butadiene copolymers and chlorinated rubber. Optionally, the binder is polyvinylidene fluoride.

[0034] In some embodiments, the conductive agent can be selected from at least one of the following groups: natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber, carbon nanotubes, graphene, mesoporous ordered carbon, activated carbon, metal powder, metal fiber and conductive polymer, optionally, the conductive agent is super P.

[0035] In some embodiments, based on the total weight of the cathode active material introduced with an inorganic single ion conductor material or the cathode active material with an inorganic single ion conductor material coated on the surface, the binder and the conductive agent, the cathode active material introduced with an inorganic single ion conductor material or the cathode active material with an inorganic single ion conductor material coated on the surface accounts for 90-98 weight%, and / or the conductive agent accounts for 1-5 weight%, and / or the binder accounts for 1-5 weight%.

[0036] In some embodiments, the organic solvent can be selected from one or more of ethanol, ethylene glycol, methanol, cyclohexane, carbon tetrachloride, chloroform, dichloromethane, dimethylformamide, dimethylacetamide and N-methylpyrrolidone or a mixture thereof, and can be selected from anhydrous ethanol and N-methylpyrrolidone.

[0037] In a fourth aspect, the present application provides a lithium-ion battery, comprising the cathode electrode, the separator and the anode electrode according to the first aspect of the present application.

[0038] In some embodiments, the kinetic performance of the lithium-ion battery is improved by 1.2 to 1.5 times, specifically, the discharge time of the lithium-ion battery can be as high as 110-130 seconds.

[0039] In some embodiments, the energy density of lithium-ion batteries can be as high as 400-500 Wh / kg.

[0040] In a fifth aspect, the present application provides an electrical device, comprising a lithium-ion battery as described in the fourth aspect of the present application, wherein the lithium-ion battery serves as a power source for the electrical device.

[0041] In a sixth aspect, the present application provides a method for preparing a cathode plate comprising an active material layer including a cathode active material and an inorganic single ion conductor material, or including a cathode active material coated with an inorganic single ion conductor material, wherein the cathode plate comprises a current collector and an active material layer, wherein the active material layer is coated on at least one surface of the current collector, and wherein the ionic conductivity of the inorganic single ion conductor material is ≥3×10 -3 S / cm, and the coating weight of the active material layer was 24 mg / cm 2 -43mg / cm 2 .

[0042] In some embodiments, the inorganic single ion conductor material is selected from lithium lanthanum titanate (Li 0.33 La 0.56 TiO3, LLTO), lithium aluminum titanium phosphate (Li 1.3 Al 0.3 Ti 1.7 (PO4)3, LATP), lithium germanium aluminum phosphate (Li 1.5 Al 0.5 Ge 1.5 (PO4)3, LAGP), lithium germanium phosphorus sulfur (Li 10 GeP2S 12 , LGPS), antiperovskite type (Li3OX), glassy sulfide (yLi2S·(100-y)P2S5) and halogen sulfide (Li6PS5X), wherein X is selected from Cl, Br or I.

[0043] Among the above optional materials, lithium lanthanum titanium oxide (Li0.33 La 0.56 The ionic conductivity of TiO3, LLTO) is about 3×10 -3 S / cm; Lithium aluminum titanium phosphate (Li 1.3 Al 0.3 Ti 1.7 The ionic conductivity of (PO4)3, LATP) is about 3×10 -3 S / cm; Lithium Germanium Aluminum Phosphate (Li 1.5 Al 0.5 Ge 1.5 The ionic conductivity of (PO4)3, LAGP) is about 6×10 -3 S / cm; Lithium Germanium Phosphorus Sulfur (Li 10 GeP2S 12 The ionic conductivity of LGPS is about 4×10 -3 S / cm); the ionic conductivity of the antiperovskite type (Li3OX, where X=Cl, Br or I) is about 4×10 -3 S / cm; the ionic conductivity of glassy sulfide (yLi2S·(100-y)P2S5) is about 5×10 -3 S / cm); and the ionic conductivity of halogen sulfide (Li6PS5X, where X is Cl, Br or I) is about 5×10 -3 S / cm.

[0044] In some embodiments, the cathode active material of the present application may include a chemical formula of LiNi m Co n Mn b One or more of a ternary material of O2 and a doping and coating material thereof, wherein m+n+b=1, and 0.96≤m≤0.995.

[0045] In some embodiments, the glassy sulfide may include 25Li2S·75P2S5.

[0046] In some embodiments, the inorganic single ion conductor material may be doped with elements such as Ga, Ta, W, or Al. Those skilled in the art will appreciate that the inorganic single ion conductor material may be doped with one or more of the elements Ga, Ta, W, and Al, as long as such doping is expected to further enhance its ionic conductivity.

[0047] In some embodiments, the inorganic single ion conductor material is a nanoparticle, which may be 20-500 nm nanoparticles, or 50-200 nm nanoparticles; or the inorganic single ion conductor material is a nanowire, which may have an aspect ratio of 5-200, or 10-50 nanowires.

[0048] In some embodiments, the mass of the inorganic single ion conductor material may account for 0.1-5%, and optionally 0.5-5%, of the total mass of the inorganic single ion conductor material and the cathode active material. Within this mass ratio, both excellent kinetic performance and energy density can be achieved.

[0049] To make the above-mentioned objects, features, and advantages of the present application more clearly understood, the specific embodiments of the present application are described in detail below. The following description sets forth many specific details to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways than those described herein, and those skilled in the art can make similar modifications without violating the scope of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below.

[0050] In this application, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0051] In this application, when referring to numerical ranges, unless otherwise specified, the numerical ranges are considered continuous and include the minimum and maximum values ​​of the range, as well as every value between such minimum and maximum values. Further, when a range refers to an integer, every integer between the minimum and maximum values ​​of the range is included. In addition, when multiple ranges are provided to describe a feature or characteristic, the ranges can be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges subsumed therein.

[0052] The temperature parameters in this application, unless otherwise specified, allow for both constant temperature treatment and treatment within a certain temperature range. Constant temperature treatment allows for temperature fluctuations within the precision range of instrument control.

[0053] It should be understood that the terms "upper", "lower" and similar expressions used herein are for illustrative purposes only and do not represent the only implementation methods.

[0054] The applicant has noticed that the lithium-ion battery in the traditional technology includes a cathode electrode, which usually includes a cathode current collector and an active material layer provided on the cathode current collector, and the active material layer includes an active material, an adhesive and a conductive agent. However, with the development of science and technology and the promotion and application of batteries, the existing cathode electrode cannot meet the higher requirements for battery energy density and safety. In the manufacturing process of the cathode electrode, a ternary system material is usually selected as the cathode material of the cathode electrode. The ternary system material has a high energy density and a wide range of applications. However, the demand for the cathode of the lithium-ion battery system with a higher energy density can only be achieved by combining the cathode active material with a thick film electrode design, but the thick electrode causes the lithium ion transmission distance to be lengthened, resulting in insufficient ion transmission channels and causing kinetic deterioration.

[0055] In order to obtain a battery with higher kinetic performance, the applicant has found that the main material of the cathode active material of the membrane can be selected to have an ionic conductivity of ≥3×10 -3 S / cm. By introducing inorganic single-ion conductor materials with high ionic conductivity into the cathode active material, continuous / multiple ion transport channels are provided for thick film electrodes.

[0056] The inorganic single ion conductor introduced in this application has a three-dimensional ion transport channel and high ionic conductivity (≥3×10 -3 S / cm), and possesses the ability to rapidly conduct ions. Introducing an inorganic single-ion conductor into the cathode active material can accelerate the ion transport rate across the cathode active material particle surface, forming continuous ion transport channels between particles and constructing multiple ion transport pathways. This overcomes the limited ion transport capacity in thick-film electrodes and improves kinetic performance.

[0057] In some embodiments, the kinetic performance of a lithium-ion battery using a cathode electrode sheet containing an active material layer of the present application will be improved by 1.2 to 1.5 times, specifically, the discharge time of the lithium-ion battery can be as high as 110-130 seconds, and the energy density can be as high as 400-500Wh / kg.

[0058] The advantages of the embodiments of the present application will be further illustrated in the following examples, which are intended to illustrate the present application but not to limit it. Specific implementation plan

[0059] Example 1: Preparation of a cathode electrode using an active material layer comprising a cathode active material coated with LLTO

[0060] The preparation method comprises the following steps:

[0061] a. 100 g (g) of cathode active material LiNi 0.96 Co 0.02 Mn 0.02 O2 was added to 100 milliliters (ml) of ethanol solution and dispersed evenly;

[0062] b. According to the stoichiometric ratio, 86.5 mg (mg) LiNO3, 691.4 mg LaNO3 and 961.9 mg titanium isopropoxide of the LLTO precursor were added to the ethanol solution and mixed uniformly;

[0063] c. The above solution was heated to dryness, and then transferred to a furnace and heated at 500°C in an air atmosphere for 12 hours (h) to obtain a cathode active material coated with LLTO.

[0064] d. The obtained surface-coated LLTO cathode active material, binder PVDF-1, and conductive agent Super P conductive carbon black were mixed and dispersed in a solvent N-methylpyrrolidone at a mass ratio of 97.0wt%:1.5wt%:1.5wt% to form a slurry. The slurry was coated on the cathode current collector and dried and cold-pressed to obtain a thick cathode electrode sheet with a coating weight of 30 mg / cm2. 2 ).

[0065] Optionally, a battery is prepared by further using the cathode electrode obtained in step d above and the following negative electrode electrode, separator and electrolyte:

[0066] Negative electrode sheet: The negative electrode active material graphite, the conductive agent Super P conductive carbon black, and the binder styrene-butadiene rubber (SBR) are dissolved in the solvent deionized water in a weight ratio of 92:4:4, and mixed evenly to prepare the negative electrode slurry; the negative electrode slurry is evenly coated on the negative electrode current collector copper foil once or multiple times, and the negative electrode sheet is obtained after drying, cold pressing, and slitting.

[0067] Separator film: PE film with ceramic coating.

[0068] Electrolyte: lithium hexafluorophosphate LiPF6 is used as the electrolyte, and its content in the electrolyte is 10%. A mixture of EC+PC (ethylene carbonate+propylene carbonate) with a volume ratio of 3:7 is used as the solvent.

[0069] The positive and negative electrodes and separators are combined to form a bare cell. The bare cell is then insulated and encased in an aluminum shell. The top cover is then welded to form a dry cell. The dry cell is baked, then injected with electrolyte, and subjected to formation and aging to create a hard-shell battery.

[0070] Example 2: Preparation of a cathode electrode using an active material layer comprising a cathode active material coated with LATP

[0071] The preparation method comprises the following steps:

[0072] a. 100g cathode active material LiNi 0.96 Co 0.02 Mn 0.02 O2 was added to 100 ml of ethanol solution and dispersed evenly;

[0073] b. According to the stoichiometric ratio, 419.2mg TiCl4, 52mg AlCl3, 382.2ml H3PO4 and 111.8mg lithium isopropoxide of the LATP precursor were added to the ethanol solution and mixed uniformly;

[0074] c. The above solution was heated to dryness, and then transferred to a furnace and heated at 600°C for 12h in an air atmosphere to obtain a cathode active material coated with LATP.

[0075] d. The obtained cathode active material coated with LATP, binder PVDF-1, and conductive agent Super P conductive carbon black were mixed and dispersed in a solvent N-methylpyrrolidone at a mass ratio of 97.0wt%:1.5wt%:1.5wt% to form a slurry. The slurry was coated on the cathode current collector and dried and cold pressed to obtain a thick cathode electrode sheet with a coating weight of 26mg / cm 2 .

[0076] Optionally, a battery is prepared by further using the cathode electrode obtained in step d above and the following negative electrode electrode, separator and electrolyte:

[0077] Negative electrode sheet: The negative electrode active material graphite, the conductive agent Super P conductive carbon black, and the binder styrene-butadiene rubber (SBR) are dissolved in the solvent deionized water in a weight ratio of 92:4:4, and mixed evenly to prepare the negative electrode slurry; the negative electrode slurry is evenly coated on the negative electrode current collector copper foil once or multiple times, and the negative electrode sheet is obtained after drying, cold pressing, and slitting.

[0078] Separator film: PE film with ceramic coating.

[0079] Electrolyte: lithium hexafluorophosphate LiPF6 is used as the electrolyte, and its content in the electrolyte is 10%. A mixture of EC+PC (ethylene carbonate+propylene carbonate) with a volume ratio of 3:7 is used as the solvent.

[0080] The positive and negative electrodes and separators are combined to form a bare cell. The bare cell is then insulated and encased in an aluminum shell. The top cover is then welded to form a dry cell. The dry cell is baked, then injected with electrolyte, and subjected to formation and aging to create a hard-shell battery.

[0081] Example 3: Preparation of a cathode electrode using an active material layer comprising a cathode active material coated with LAGP

[0082] The preparation method comprises the following steps:

[0083] a. 100g cathode active material LiNi 0.97 Co 0.01 Mn 0.02 O2 is added to 100ml of ammonia solution and dispersed evenly;

[0084] b according to the stoichiometric ratio, followed by the LAGP precursor 188.3mg germanium dioxide, 43.2mg lithium hydroxide, 127.8mg aluminum nitrate and 352.8ml H3PO4 were added to the above ammonia solution and mixed;

[0085] c. The above solution was heated to dryness, and then transferred to a furnace and heated at 550°C for 12h in an air atmosphere to obtain a cathode active material coated with LAGP.

[0086] d. The obtained cathode active material coated with LAGP, binder PVDF-1, and conductive agent Super P conductive carbon black were mixed and dispersed in a solvent N-methylpyrrolidone at a mass ratio of 97.0wt%:1.5wt%:1.5wt% to form a slurry. The slurry was coated on the cathode current collector and dried and cold pressed to obtain a thick cathode electrode sheet with a coating weight of 28mg / cm 2 .

[0087] Optionally, a battery is prepared by further using the cathode electrode obtained in step d above and the following negative electrode electrode, separator and electrolyte:

[0088] Negative electrode sheet: The negative electrode active material graphite, the conductive agent Super P conductive carbon black, and the binder styrene-butadiene rubber (SBR) are dissolved in the solvent deionized water in a weight ratio of 92:4:4, and mixed evenly to prepare the negative electrode slurry; the negative electrode slurry is evenly coated on the negative electrode current collector copper foil once or multiple times, and the negative electrode sheet is obtained after drying, cold pressing, and slitting.

[0089] Separator film: PE film with ceramic coating.

[0090] Electrolyte: lithium hexafluorophosphate LiPF6 is used as the electrolyte, and its content in the electrolyte is 10%. A mixture of EC+PC (ethylene carbonate+propylene carbonate) with a volume ratio of 3:7 is used as the solvent.

[0091] The positive and negative electrodes and separators are combined to form a bare cell. The bare cell is then insulated and encased in an aluminum shell. The top cover is then welded to form a dry cell. The dry cell is baked, then injected with electrolyte, and subjected to formation and aging to create a hard-shell battery.

[0092] Example 4: Preparation of a cathode electrode using an active material layer comprising a cathode active material coated with LGPS

[0093] The preparation method comprises the following steps:

[0094] a. 100g cathode active material LiNi 0.96 Co 0.02 Mn 0.02 O2 was added to 40 ml of 1,2-ethylenediamine and 60 ml of 1,2-ethanedithiol solution and dispersed evenly;

[0095] b. According to the stoichiometric ratio, 391mg lithium sulfide, 232.2mg GeS2 and 377.9mg P2S5 of the LGPS precursor were added to the above solution and mixed uniformly;

[0096] c. The above solution was heated to dryness, and then transferred to a furnace and heated at 500 ° C for 6 h in an inert atmosphere to obtain a cathode active material coated with LGPS.

[0097] d. The obtained cathode active material coated with LGPS, binder PVDF-1, and conductive agent Super P conductive carbon black were mixed and dispersed in a solvent N-methylpyrrolidone in a mass ratio of 97.0wt%:1.5wt%:1.5wt% to form a slurry. The slurry was coated on the cathode current collector and dried and cold pressed to obtain a thick cathode electrode sheet with a coating weight of 33mg / cm 2 .

[0098] Optionally, a battery is prepared by further using the cathode electrode obtained in step d above and the following negative electrode electrode, separator and electrolyte:

[0099] Negative electrode sheet: The negative electrode active material graphite, the conductive agent Super P conductive carbon black, and the binder styrene-butadiene rubber (SBR) are dissolved in the solvent deionized water in a weight ratio of 92:4:4, and mixed evenly to prepare the negative electrode slurry; the negative electrode slurry is evenly coated on the negative electrode current collector copper foil once or multiple times, and the negative electrode sheet is obtained after drying, cold pressing, and slitting.

[0100] Separator film: PE film with ceramic coating.

[0101] Electrolyte: lithium hexafluorophosphate LiPF6 is used as the electrolyte, and its content in the electrolyte is 10%. A mixture of EC+PC (ethylene carbonate+propylene carbonate) with a volume ratio of 3:7 is used as the solvent.

[0102] The positive and negative electrodes and separators are combined to form a bare cell. The bare cell is then insulated and encased in an aluminum shell. The top cover is then welded to form a dry cell. The dry cell is baked, then injected with electrolyte, and subjected to formation and aging to create a hard-shell battery.

[0103] Example 5: Preparation of a cathode electrode using an active material layer comprising a cathode active material coated with Li3OCl

[0104] The preparation method comprises the following steps:

[0105] a. 100g cathode active material LiNi 0.98 Co 0.01 Mn 0.01 O2 was added to 100 ml of ethanol solution and dispersed evenly;

[0106] b. According to the stoichiometric ratio, 331 mg of lithium hydroxide, 414 mg of lithium oxide and 585.1 mg of lithium chloride of the Li3OCl precursor were added to the ethanol solution and mixed uniformly;

[0107] c. The above solution was heated to dryness, and then transferred to a furnace and heated at 400°C for 8h in an inert atmosphere to obtain a cathode active material coated with Li3OCl.

[0108] d. The obtained cathode active material coated with Li3OCl, binder PVDF-1, and conductive agent Super P conductive carbon black were mixed and dispersed in a solvent N-methylpyrrolidone in a mass ratio of 97.0wt%:1.5wt%:1.5wt% to form a slurry. The slurry was coated on the cathode current collector and dried and cold pressed to obtain a thick cathode electrode sheet with a coating weight of 35mg / cm 2 .

[0109] Optionally, a battery is prepared by further using the cathode electrode obtained in step d above and the following negative electrode electrode, separator and electrolyte:

[0110] Negative electrode sheet: The negative electrode active material graphite, the conductive agent Super P conductive carbon black, and the binder styrene-butadiene rubber (SBR) are dissolved in the solvent deionized water in a weight ratio of 92:4:4, and mixed evenly to prepare the negative electrode slurry; the negative electrode slurry is evenly coated on the negative electrode current collector copper foil once or multiple times, and the negative electrode sheet is obtained after drying, cold pressing, and slitting.

[0111] Separator film: PE film with ceramic coating.

[0112] Electrolyte: lithium hexafluorophosphate LiPF6 is used as the electrolyte, and its content in the electrolyte is 10%. A mixture of EC+PC (ethylene carbonate+propylene carbonate) with a volume ratio of 3:7 is used as the solvent.

[0113] The positive and negative electrodes and separators are combined to form a bare cell. The bare cell is then insulated and encased in an aluminum shell. The top cover is then welded to form a dry cell. The dry cell is baked, then injected with electrolyte, and subjected to formation and aging to create a hard-shell battery.

[0114] Example 6: Preparation of a cathode electrode using an active material layer comprising a cathode active material coated with 25Li2S·75P2S5

[0115] The preparation method comprises the following steps:

[0116] a. 100g cathode active material LiNi 0.96 Co 0.02 Mn 0.02O2 was added to 100 ml of ethanol solution and dispersed evenly;

[0117] b. According to the stoichiometric ratio, 64.5 mg Li2S and 935.5 mg P2S5 of the 25Li2S·75P2S5 precursor were added to the above ethanol solution and mixed uniformly;

[0118] c. The above solution was heated to dryness, and then transferred to a furnace and heated at 400°C in an inert atmosphere for 6 h to obtain a cathode active material coated with 25Li2S·75P2S5.

[0119] d. The obtained surface-coated cathode active material with 25Li2S·75P2S5, binder PVDF-1, and conductive agent Super P conductive carbon black were mixed and dispersed in a solvent N-methylpyrrolidone at a mass ratio of 97.0wt%:1.5wt%:1.5wt% to form a slurry. The slurry was coated on the cathode current collector and dried and cold-pressed to obtain a thick cathode electrode sheet with a coating weight of 38mg / cm 2 .

[0120] Optionally, a battery is prepared by further using the cathode electrode obtained in step d above and the following negative electrode electrode, separator and electrolyte:

[0121] Negative electrode sheet: The negative electrode active material graphite, the conductive agent Super P conductive carbon black, and the binder styrene-butadiene rubber (SBR) are dissolved in the solvent deionized water in a weight ratio of 92:4:4, and mixed evenly to prepare the negative electrode slurry; the negative electrode slurry is evenly coated on the negative electrode current collector copper foil once or multiple times, and the negative electrode sheet is obtained after drying, cold pressing, and slitting.

[0122] Separator film: PE film with ceramic coating.

[0123] Electrolyte: lithium hexafluorophosphate LiPF6 is used as the electrolyte, and its content in the electrolyte is 10%. A mixture of EC+PC (ethylene carbonate+propylene carbonate) with a volume ratio of 3:7 is used as the solvent.

[0124] The positive and negative electrodes and separators are combined to form a bare cell. The bare cell is then insulated and encased in an aluminum shell. The top cover is then welded to form a dry cell. The dry cell is baked, then injected with electrolyte, and subjected to formation and aging to create a hard-shell battery.

[0125] Example 7: Preparation of a cathode electrode using an active material layer comprising a cathode active material coated with Li6PS5Cl

[0126] The preparation method comprises the following steps:

[0127] a. 100g cathode active material LiNi 0.96Co 0.02 Mn 0.02 O2 is added to 100ml of ethylenediamine solution and dispersed evenly;

[0128] b. According to the stoichiometric ratio, 644mg Li2S, 237.4mgLiCl and 622.4mgP2S5 of the Li6PS5Cl precursor were added to the above ethanol solution and mixed uniformly;

[0129] c. The above solution was heated to dryness, and then transferred to a furnace and heated at 550°C for 10 h in an inert atmosphere to obtain a cathode active material coated with Li6PS5Cl.

[0130] d. The cathode active material coated with Li6PS5Cl, the binder PVDF-1, and the conductive agent Super P conductive carbon black were mixed and dispersed in a solvent N-methylpyrrolidone in a mass ratio of 97.0wt%:1.5wt%:1.5wt% to form a slurry. The slurry was coated on the cathode current collector and dried and cold pressed to obtain a thick cathode electrode sheet with a coating weight of 25mg / cm 2 .

[0131] Optionally, a battery is prepared by further using the cathode electrode obtained in step d above and the following negative electrode electrode, separator and electrolyte:

[0132] Negative electrode sheet: The negative electrode active material graphite, the conductive agent Super P conductive carbon black, and the binder styrene-butadiene rubber (SBR) are dissolved in the solvent deionized water in a weight ratio of 92:4:4, and mixed evenly to prepare the negative electrode slurry; the negative electrode slurry is evenly coated on the negative electrode current collector copper foil once or multiple times, and the negative electrode sheet is obtained after drying, cold pressing, and slitting.

[0133] Separator film: PE film with ceramic coating.

[0134] Electrolyte: lithium hexafluorophosphate LiPF6 is used as the electrolyte, and its content in the electrolyte is 10%. A mixture of EC+PC (ethylene carbonate+propylene carbonate) with a volume ratio of 3:7 is used as the solvent.

[0135] The positive and negative electrodes and separators are combined to form a bare cell. The bare cell is then insulated and encased in an aluminum shell. The top cover is then welded to form a dry cell. The dry cell is baked, then injected with electrolyte, and subjected to formation and aging to create a hard-shell battery.

[0136] Example 8: Using LLTO (Li 0.33 La 0.56 Ga 0.25 Ti 0.75 O3) cathode active material layer to prepare cathode pole piece

[0137] The preparation method comprises the following steps:

[0138] a. 100g cathode active material LiNi 0.96 Co 0.02 Mn 0.02 O2 was added to 100 ml of ethanol solution and dispersed evenly;

[0139] b. According to the stoichiometric ratio, 84.2 mg LiNO 3 , 673.2 mg LaNO 3 , 236.5 mg Ga (NO 3 ) 3 and 702.4 mg titanium isopropoxide of the Ga-doped LLTO precursor were added to the ethanol solution and mixed uniformly;

[0140] c. The above solution was heated to dryness, and then transferred to a furnace and heated at 500 ° C for 12 h in an air atmosphere to obtain LLTO (Li 0.33 La 0.56 Ga 0.25 Ti 0.75 O3) cathode active material.

[0141] d. The resulting surface is coated with Ga-doped LLTO (Li 0.33 La 0.56 Ga 0.25 Ti 0.75 The cathode active material (O3), the binder PVDF-1, and the conductive agent Super P conductive carbon black were mixed and dispersed in the solvent N-methylpyrrolidone in a mass ratio of 97.0wt%:1.5wt%:1.5wt% to form a slurry. The slurry was coated on the cathode current collector, and after drying and cold pressing, a thick cathode electrode sheet was obtained. The coating weight was 36mg / cm 2 .

[0142] Optionally, a battery is prepared by further using the cathode electrode obtained in step d above and the following negative electrode electrode, separator and electrolyte:

[0143] Negative electrode sheet: The negative electrode active material graphite, the conductive agent Super P conductive carbon black, and the binder styrene-butadiene rubber (SBR) are dissolved in the solvent deionized water in a weight ratio of 92:4:4, and mixed evenly to prepare the negative electrode slurry; the negative electrode slurry is evenly coated on the negative electrode current collector copper foil once or multiple times, and the negative electrode sheet is obtained after drying, cold pressing, and slitting.

[0144] Separator film: PE film with ceramic coating.

[0145] Electrolyte: lithium hexafluorophosphate LiPF6 is used as the electrolyte, and its content in the electrolyte is 10%. A mixture of EC+PC (ethylene carbonate+propylene carbonate) with a volume ratio of 3:7 is used as the solvent.

[0146] The positive and negative electrodes and separators are combined to form a bare cell. The bare cell is then insulated and encased in an aluminum shell. The top cover is then welded to form a dry cell. The dry cell is baked, then injected with electrolyte, and subjected to formation and aging to create a hard-shell battery.

[0147] Example 9: Preparation of a cathode electrode sheet using an active material layer including a cathode active material incorporating LATP

[0148] The LATP precursor 419.2 mg TiCl4, 52 mg AlCl3, 382.2 ml H3PO4 and 111.8 mg lithium isopropoxide were added to 100 ml ethanol solution and mixed evenly. The above solution was heated until dry, then transferred to a furnace and heated at 600 ° C in air atmosphere for 12 hours to obtain LATP.

[0149] The above LATP was mixed with 100g of cathode active material LiNi 0.96 Co 0.02 Mn 0.02 A mixture of O2, binder polyvinylidene fluoride and conductive agent Super P were mixed and dispersed in a solvent N-methylpyrrolidone in a mass ratio of 97.0wt%:1.5wt%:1.5wt% to form a slurry. The slurry was coated on the cathode current collector and dried and cold pressed to obtain a thick cathode electrode sheet with a coating weight of 26mg / cm 2 .

[0150] Optionally, a battery is prepared by further using the cathode electrode obtained in step d above and the following negative electrode electrode, separator and electrolyte:

[0151] Negative electrode sheet: The negative electrode active material graphite, the conductive agent Super P conductive carbon black, and the binder styrene-butadiene rubber (SBR) are dissolved in the solvent deionized water in a weight ratio of 92:4:4, and mixed evenly to prepare the negative electrode slurry; the negative electrode slurry is evenly coated on the negative electrode current collector copper foil once or multiple times, and the negative electrode sheet is obtained after drying, cold pressing, and slitting.

[0152] Separator film: PE film with ceramic coating.

[0153] Electrolyte: lithium hexafluorophosphate LiPF6 is used as the electrolyte, and its content in the electrolyte is 10%. A mixture of EC+PC (ethylene carbonate+propylene carbonate) with a volume ratio of 3:7 is used as the solvent.

[0154] The positive and negative electrodes and separators are combined to form a bare cell. The bare cell is then insulated and encased in an aluminum shell. The top cover is then welded to form a dry cell. The dry cell is baked, then injected with electrolyte, and subjected to formation and aging to create a hard-shell battery.

[0155] Comparative Example 1: Preparation of a cathode electrode using an active material layer comprising a cathode active material coated with LLZO

[0156] The preparation method comprises the following steps:

[0157] a. 100g cathode active material LiNi 0.96 Co 0.02 Mn 0.02 O2 was added to 100 ml of ethanol solution and dispersed evenly;

[0158] b. According to the stoichiometric ratio, LLZO (whose ionic conductivity is 1.8×10 -3 S / cm) precursor 141.4 mg LiOH, 205.1 mg La2O3 and 360.2 mg ZrO2 were added to the above ethanol solution and mixed well;

[0159] c. The above solution was heated to dryness, and then transferred to a furnace and heated at 500°C for 12 h in an air atmosphere to obtain a cathode active material coated with LLZO.

[0160] d. The obtained surface-coated LLZO cathode active material, binder PVDF-1, and conductive agent Super P conductive carbon black were mixed and dispersed in a solvent N-methylpyrrolidone in a mass ratio of 97.0wt%:1.5wt%:1.5wt% to form a slurry. The slurry was coated on the cathode current collector and dried and cold-pressed to obtain a thick cathode electrode sheet with a coating weight of 30mg / cm 2 .

[0161] Optionally, a battery is prepared by further using the cathode electrode obtained in step d above and the following negative electrode electrode, separator and electrolyte:

[0162] Negative electrode sheet: The negative electrode active material graphite, the conductive agent Super P conductive carbon black, and the binder styrene-butadiene rubber (SBR) are dissolved in the solvent deionized water in a weight ratio of 92:4:4, and mixed evenly to prepare the negative electrode slurry; the negative electrode slurry is evenly coated on the negative electrode current collector copper foil once or multiple times, and the negative electrode sheet is obtained after drying, cold pressing, and slitting.

[0163] Separator film: PE film with ceramic coating.

[0164] Electrolyte: lithium hexafluorophosphate LiPF6 is used as the electrolyte, and its content in the electrolyte is 10%. A mixture of EC+PC (ethylene carbonate+propylene carbonate) with a volume ratio of 3:7 is used as the solvent.

[0165] The positive and negative electrodes and separators are combined to form a bare cell. The bare cell is then insulated and encased in an aluminum shell. The top cover is then welded to form a dry cell. The dry cell is baked, then injected with electrolyte, and subjected to formation and aging to create a hard-shell battery.

[0166] Experimental Example 1: Characterization of the dynamic performance of the battery prepared using the cathode electrode of the embodiment of the present application

[0167] The batteries (modified group) prepared with the cathode pole pieces of Examples 1-9 of the present application and the control batteries (batteries prepared with the cathode pole piece of Comparative Example 1) were discharged at a rate of 5C under 40% SOC (State of Charge) conditions, and the discharge time t was recorded to characterize the kinetic performance. The results are as follows.

Claims

1. A cathode electrode, comprising: current collector; and active material layer, The active material layer is disposed on at least one surface of the current collector, The active material layer comprises a cathode active material and an inorganic single ion conductor material, or the active material layer comprises a cathode active material with an inorganic single ion conductor material coated on its surface, The ionic conductivity of the inorganic single ion conductor material is ≥3×10 -3 S / cm; The coating weight of the active material layer is 24 mg / cm 2 -43mg / cm 2 .

2. The cathode electrode according to claim 1, wherein the inorganic single ion conductor material comprises at least one of the following: lithium lanthanum titanium oxide (Li 0.33 La 0.56 TiO3), lithium aluminum titanium phosphate (Li 1.3 Al 0.3 Ti 1.7 (PO4)3), lithium germanium aluminum phosphate (Li 1.5 Al 0.5 Ge 1.5 (PO4)3), lithium germanium phosphorus sulfide (Li 10 GeP2S 12 ), antiperovskite materials (Li3OX), glassy sulfides (yLi2S·(100-y)P2S5) and halogen sulfides (Li6PS5X), where 0<y<100, and X is selected from Cl, Br or I.

3. The cathode electrode according to claim 1 or 2, wherein the cathode active material comprises a chemical formula of LiNi m Co n Mn b One or more of the ternary materials of O2 and the doped and coated materials thereof, wherein m+n+b=1, and 0.96≤m≤0.

995.

4. The cathode electrode according to claim 2 or 3, wherein the glassy sulfide is 25Li2S·75P2S5. 5 . The cathode electrode according to claim 1 , wherein the inorganic single ion conductor material is doped with one or more of Ga, Ta, W and Al elements.

6. The cathode electrode according to any one of claims 1 to 5, wherein the inorganic single ion conductor material is nanoparticles, preferably nanoparticles of 20-500 nm, more preferably nanoparticles of 50-200 nm; or the inorganic single ion conductor material is nanowires, preferably nanowires with an aspect ratio of 5-200, more preferably nanowires with an aspect ratio of 10-50.

7. The cathode electrode according to any one of claims 1 to 6, wherein the mass of the inorganic single ion conductor material accounts for 0.1-5%, preferably 0.5-5%, of the total mass of the inorganic single ion conductor material and the cathode active material.

8. A lithium ion battery comprising the cathode electrode sheet according to any one of claims 1 to 7.

9. An electrical device comprising the lithium-ion battery as claimed in claim 8.

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