Solid-state battery and preparation method thereof, battery device, power utilization device and energy storage device

Abstract

The invention relates to the technical field of new energy, in particular to a solid-state battery and a preparation method thereof, a battery device, a power utilization device and an energy storage device. The solid-state battery comprises a positive pole piece, a negative pole piece and a solid-state electrolyte positioned between the positive pole piece and the negative pole piece, the positive pole piece comprises a positive current collector and a positive active layer located on the positive current collector, and the positive current collector comprises a first porous current collector and a first oxide array located on the surface of the first porous current collector; and / or the negative pole piece comprises a negative current collector and a negative active layer located on the negative current collector, and the negative current collector comprises a second porous current collector and a second oxide array located on the surface of the second porous current collector. And the solid-state battery has relatively good rate capability, cycling stability and cycling life.

Description

Technical Field

[0001] This application relates to the field of new energy technology, and in particular to solid-state batteries and their preparation methods, battery devices, power consumption devices and energy storage devices. Background Technology

[0002] In traditional liquid lithium-ion batteries, the electrolyte exhibits excellent fluidity and wettability. This good fluidity and wettability allow the electrolyte to fully penetrate the electrode plates, forming a tight ion-contact interface. However, as the industry moves towards solid-state batteries with higher energy density and safety, a significant challenge arises: the electrolyte in solid-state batteries is solid, and its contact with the electrode plates is a solid-solid interface, making it difficult for the solid electrolyte to wet the electrode plates. This issue has become one of the key bottlenecks restricting the commercial application of solid-state batteries. Summary of the Invention

[0003] Based on this, the first aspect of this application provides a solid-state battery, the technical solution of which is as follows:

[0004] A solid-state battery includes a positive electrode, a negative electrode, and a solid electrolyte located between the positive electrode and the negative electrode.

[0005] The positive electrode includes a positive current collector and a positive active layer located on the positive current collector; the positive current collector includes a first porous current collector and a first oxide array located on the surface of the first porous current collector; and / or,

[0006] The negative electrode sheet includes a negative current collector and a negative active layer located on the negative current collector. The negative current collector includes a second porous current collector and a second oxide array located on the surface of the second porous current collector.

[0007] The second aspect of this application provides a method for preparing a solid-state battery, the technical solution of which is as follows:

[0008] A method for preparing a solid-state battery includes the following steps:

[0009] A method for preparing a positive electrode and / or a negative electrode includes the following steps: forming a first oxide array on the surface of a first porous current collector to prepare a positive current collector; forming a positive active layer on one side of the first oxide array of the positive current collector to prepare a positive electrode; and a method for preparing a negative electrode includes the following steps: forming a second oxide array on the surface of a second porous current collector to prepare a negative current collector; and forming a negative active layer on one side of the second oxide array of the negative current collector to prepare a negative electrode.

[0010] The positive and negative electrode sheets are assembled according to the battery structure, and an electrolyte precursor solution is injected between the positive and negative electrode sheets. The mixture is then hot-pressed to form a solid electrolyte located between the positive and negative electrode sheets.

[0011] A third aspect of this application provides a battery device comprising a solid-state battery as described above or a solid-state battery prepared by the preparation method described above.

[0012] A fourth aspect of this application provides an electrical device comprising a battery device as described above, the battery device being used to provide electrical energy.

[0013] The fifth aspect of this application provides an energy storage device comprising a battery device as described above, the battery device being used to store electrical energy.

[0014] Compared with traditional solutions, this application has the following advantages:

[0015] The electrode current collector of this application includes a porous current collector and an oxide array located on the surface of the porous current collector. The porous structure of the current collector is beneficial for increasing the penetration depth of the solid electrolyte. Simultaneously, the oxide array forms a three-dimensional interface. On the one hand, the oxide array increases the specific surface area, increases the contact sites with the solid electrolyte, and promotes ion adsorption and transport at the interface. On the other hand, unlike a continuous oxide film, the oxide array provides less obstruction to the pore channels of the porous current collector, facilitating the penetration of the solid electrolyte into the pores of the current collector. Furthermore, the contact between the oxide array and the porous current collector is a "point contact," which can alleviate interfacial stress, prevent film cracking, and maintain interfacial stability. The electrode current collector with the above structure is beneficial for improving the wetting of the electrode plates by the solid electrolyte, optimizing the ion conduction path, significantly reducing polarization during high-rate charging, and improving battery rate performance and cycle stability. At the same time, the oxide array can also improve the adhesion between the electrode active layer and the electrode current collector, avoiding the problem of delamination at the current collector interface caused by large volume changes of the electrode active material during solid-state battery charging and discharging, thus improving cycle life. Detailed Implementation

[0016] The present application will be further described in detail below with reference to specific embodiments. The present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of this application.

[0017] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0018] Unless otherwise stated or in case of contradiction, the terms or phrases used herein shall have the following meanings:

[0019] In this application, the terms "optionally," "optionally," and "optional" refer to options that are optional, meaning they can be selected from either "with" or "without." If multiple "optional" options appear in a technical solution, unless otherwise specified and there are no contradictions or mutual constraints, each "optional" option is independent.

[0020] In this application, the terms "first aspect," "second aspect," "third aspect," and "fourth aspect," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first," "second," "third," and "fourth," etc., serve only a non-exhaustive enumeration purpose and should be understood not to constitute a closed limitation on quantity.

[0021] In this application, numerical intervals (i.e. numerical ranges) are involved. Unless otherwise specified, the selected numerical distributions within the above-mentioned numerical intervals are considered continuous, and include the two numerical endpoints (i.e., the minimum value and the maximum value) of the numerical range, as well as every value between the two numerical endpoints.

[0022] Unless otherwise specified, the temperature parameters in this application are permitted to be either constant-temperature treatment or variations within a certain temperature range. It should be understood that the constant-temperature treatment allows temperature fluctuations within the precision range of the instrument control, such as ±5℃, ±4℃, ±3℃, ±2℃, or ±1℃.

[0023] The first aspect of this application provides a solid-state battery. In one embodiment, the solid-state battery includes a positive electrode, a negative electrode, and a solid electrolyte located between the positive electrode and the negative electrode.

[0024] The positive electrode includes a positive current collector and a positive active layer located on the positive current collector; the positive current collector includes a first porous current collector and a first oxide array located on the surface of the first porous current collector; and / or,

[0025] The negative electrode sheet includes a negative current collector and a negative active layer located on the negative current collector. The negative current collector includes a second porous current collector and a second oxide array located on the surface of the second porous current collector.

[0026] The electrode current collector in this embodiment includes a porous current collector and an oxide array located on the surface of the porous current collector. The porous structure of the current collector is beneficial for increasing the penetration depth of the solid electrolyte. Simultaneously, the oxide array forms a three-dimensional interface. On one hand, the oxide array increases the specific surface area, increasing the contact sites with the solid electrolyte and promoting ion adsorption and transport at the interface. On the other hand, unlike a continuous oxide film, the oxide array provides less obstruction to the pore channels of the porous current collector, facilitating the penetration of the solid electrolyte into the pores of the current collector. Furthermore, the contact between the oxide array and the porous current collector is a "point contact," which can alleviate interfacial stress, prevent film cracking, and maintain interfacial stability. The electrode current collector with the above structure improves the wetting of the electrode plates by the solid electrolyte, optimizes the ion conduction path, significantly reduces polarization during high-rate charging, and improves battery rate performance and cycle stability. At the same time, the oxide array also improves the adhesion between the electrode active layer and the electrode current collector, avoiding the problem of delamination at the current collector interface caused by large volume changes in the electrode active material during solid-state battery charging and discharging, thus improving cycle life.

[0027] In some embodiments, the solid electrolyte permeates through the first oxide array into the pores of the first porous current collector. In some embodiments, the solid electrolyte permeates through the second oxide array into the pores of the second porous current collector. In some embodiments, the solid electrolyte permeates through both the first oxide array and the second oxide array into the pores of the second porous current collector.

[0028] In some embodiments, the first oxide array includes an array of first oxide pillars, each of which is independently made of at least one of zinc oxide, aluminum oxide, lithium oxide, and titanium oxide. In some embodiments, the first oxide array is located on the surface of the first porous current collector, and the total area of ​​the orthographic projection of the first oxide array on the surface accounts for 75% to 85% of the surface area. In some embodiments, the second oxide array includes an array of second oxide pillars, each of which is independently made of at least one of zinc oxide, aluminum oxide, lithium oxide, and titanium oxide. In some embodiments, the second oxide array is located on the surface of the second porous current collector, and the total area of ​​the orthographic projection of the second oxide array on the surface accounts for 75% to 85% of the surface area. The arrangement of the first oxide array is beneficial for increasing the active sites of the first porous current collector, promoting the wetting and spreading of the solid electrolyte, improving the interfacial wettability between the positive electrode active layer and the positive electrode current collector, optimizing interfacial dynamics, and improving the adhesion between the positive electrode active layer and the positive electrode current collector, as well as improving the conductivity of the positive electrode sheet. The arrangement of the second oxide array helps to increase the active sites of the second porous current collector, promote the wetting and spreading of the solid electrolyte, improve the interfacial wettability of the negative electrode active layer and the negative electrode current collector, optimize interfacial dynamics, and improve the adhesion of the negative electrode active layer and the negative electrode current collector, as well as improve the conductivity of the negative electrode sheet.

[0029] Traditional lithium iron phosphate batteries use copper foil (negative electrode) and aluminum foil (positive electrode) as current collectors. Solid-state batteries experience significant volume changes in electrode materials during charging and discharging, easily leading to delamination between the active material and the current collector interface. Furthermore, the smooth surface of the metal foil results in weak adhesion of the active material, limiting cycle life. Additionally, electrolyte wetting issues restrict the development of solid-state batteries. In some embodiments, the first porous current collector includes at least one of foamed nickel, porous stainless steel, a metal foil composite porous carbon layer, and porous carbon fiber products. The second porous current collector includes at least one of foamed nickel, porous stainless steel, a metal foil composite porous carbon layer, and porous carbon fiber products. The pore structure of the first and second porous current collectors helps increase the penetration depth of the solid electrolyte, improving the problem of poor electrolyte wetting in solid-state batteries. The solid electrolyte is in-situ solidified on the first and second porous current collectors to form a continuous ion / electron dual-pathway network. Compared to traditional metal foils (copper foil, aluminum foil) as current collectors, the first and second porous current collectors overcome planar limitations. A first oxide array is formed on a first porous current collector, and then filled with an in-situ cured electrolyte, forming a stable "electron-ion-mechanical" triple structure. This results in high adhesion between the positive electrode active layer and the positive electrode current collector, reducing the likelihood of interfacial delamination. Similarly, a second oxide array is formed on a second porous current collector, and then filled with an in-situ cured electrolyte, forming a stable "electron-ion-mechanical" triple structure. This also results in high adhesion between the negative electrode active layer and the negative electrode current collector, reducing the likelihood of interfacial delamination. Furthermore, both the first and second porous current collectors exhibit good conductivity and high mechanical strength. The metal foil composite porous carbon layer can be a copper foil composite porous carbon layer. The porous carbon fiber product is carbon paper or carbon fiber cloth. Carbon paper and carbon fiber cloth inherit the high conductivity and corrosion resistance of carbon fibers, while also possessing porosity and self-supporting properties. Their core function is "conductive framework + fluid channel + active material carrier." In some embodiments, the pore size of the first porous current collector is 200 μm to 400 μm. The pore size of the second porous current collector is 200μm~400μm.

[0030] In some embodiments, the solid electrolyte includes a sulfide electrolyte and a polyacrylonitrile electrolyte.

[0031] In some embodiments, the positive electrode active layer includes a positive electrode active material, a binder, and a conductive agent, wherein the positive electrode active material includes lithium iron phosphate (LFP). The binder includes polyvinylidene fluoride (PVDF), and the conductive agent includes conductive carbon black.

[0032] In some embodiments, the negative electrode active layer comprises a negative electrode active material, a binder, and a conductive agent. The negative electrode active material comprises graphite, a silicon-based composite material, or lithium titanate. The binder comprises at least one of sodium carboxymethyl cellulose (CMC) and styrene-butadiene rubber (SBR), and the conductive agent comprises conductive carbon black.

[0033] A second aspect of this application provides a method for preparing a solid-state battery. In one embodiment, the method for preparing a solid-state battery includes the following steps:

[0034] A method for preparing a positive electrode and / or a negative electrode includes the following steps: forming a first oxide array on the surface of a first porous current collector to prepare a positive current collector; forming a positive active layer on one side of the first oxide array of the positive current collector to prepare a positive electrode; and a method for preparing a negative electrode includes the following steps: forming a second oxide array on the surface of a second porous current collector to prepare a negative current collector; and forming a negative active layer on one side of the second oxide array of the negative current collector to prepare a negative electrode.

[0035] The positive and negative electrode sheets are assembled according to the battery structure, and an electrolyte precursor solution is injected between the positive and negative electrode sheets. The mixture is then hot-pressed to form a solid electrolyte located between the positive and negative electrode sheets.

[0036] In some embodiments, after the electrolyte precursor solution is injected between the positive electrode and the negative electrode, the method further includes the following steps: applying ultrasound and pressure to the battery structure injected with the electrolyte precursor solution, so that the electrolyte precursor solution permeates through the first oxide array into the pores of the first porous current collector; and / or so that the electrolyte precursor solution permeates through the second oxide array into the pores of the second porous current collector.

[0037] The ultrasonic-pressure coupled infusion process enables the electrolyte precursor solution to penetrate the fine pores of the first porous current collector more quickly and uniformly through the first oxide array, and also to penetrate the fine pores of the second porous current collector more quickly and uniformly. This significantly improves infusion efficiency and uniformity, resulting in a substantial enhancement of the overall battery performance, such as improved ion conduction efficiency, increased charge / discharge capacity, and cycle stability. It also solves the problem of uneven solid electrolyte distribution in the first and second porous current collectors. Furthermore, it improves the adhesion between the positive electrode active layer and the positive electrode current collector, enhances the adhesion between the negative electrode active layer and the negative electrode current collector, and increases electrolyte wetting in the solid-state battery.

[0038] In some embodiments, the frequency of the ultrasonic wave is 20 kHz to 50 kHz. For example, the frequency of the ultrasonic wave is 20 kHz, 30 kHz, 40 kHz, or 50 kHz.

[0039] In some embodiments, the method of applying pressure is a gradient pressurization. In some embodiments, the pressure is applied according to the following sequence: 0 min to 5 min, pressure is 0.08 MPa to 0.22 MPa; 5 min to 10 min, pressure is 2.5 MPa to 5.5 MPa; 10 min to 15 min, pressure is 2.5 MPa to 10.5 MPa; 15 min to 25 min, pressure is 9 MPa to 11 MPa.

[0040] In some embodiments, the methods for depositing a first oxide array on the surface of the first porous current collector and for depositing a second oxide array on the surface of the second porous current collector each independently include an electrochemical deposition method. Controlling the process parameters of the electrochemical deposition can achieve "selective nucleation + limited growth," directly forming a discontinuous oxide array.

[0041] In some embodiments, depositing a first oxide array on the surface of the first porous current collector includes the following steps: inserting a three-electrode system A into a first electrodeposition solution to perform a first electrochemical deposition, wherein the working electrode in the three-electrode system A is the first porous current collector, and the first electrodeposition solution includes a first metal salt.

[0042] In some embodiments, depositing a second oxide array on the surface of the second porous current collector includes the following steps: inserting a three-electrode system B into a second electrodeposition solution to perform a second electrochemical deposition, wherein the working electrode in the three-electrode system B is the second porous current collector, and the second electrodeposition solution includes a second metal salt.

[0043] In some embodiments, the counter electrodes of the three-electrode system A and the three-electrode system B are each independently selected from platinum plates. The reference electrodes of the three-electrode system A and the three-electrode system B are each independently selected from silver / silver chloride electrodes.

[0044] In some embodiments, the first metal salt and the second metal salt each independently comprise at least one selected from zinc salt, aluminum salt, lithium salt, and titanium salt. The concentration of the first metal salt in the first electrodeposition solution is 0.01 mol / L to 0.1 mol / L. The concentration of the second metal salt in the second electrodeposition solution is 0.01 mol / L to 0.1 mol / L.

[0045] In some embodiments, the first electrodeposition solution and the second electrodeposition solution each independently further include a conductive salt, the conductive salt including an ammonium salt.

[0046] In some embodiments, the current density of the first electrochemical deposition and the second electrochemical deposition is each independently 0.1 mA / cm². 2 ~1mA / cm 2At the aforementioned low current density, a discontinuous oxide array can be formed. The deposition times for the first and second electrochemical depositions are each independently 10 min to 30 min. At these relatively short deposition times, a discontinuous oxide array can be formed. The ambient temperatures for the first and second electrochemical depositions are each independently 20 °C to 50 °C.

[0047] In some embodiments, the electrolyte precursor solution includes a sulfide electrolyte and a polyacrylonitrile electrolyte.

[0048] In some embodiments, the solvent of the electrolyte precursor solution includes N-methylpyrrolidone.

[0049] A third aspect of this application provides a battery device comprising a solid-state battery as described above or a solid-state battery prepared by the preparation method described above.

[0050] A fourth aspect of this application provides an electrical device comprising a battery device as described above, the battery device being used to provide electrical energy.

[0051] The fifth aspect of this application provides an energy storage device comprising a battery device as described above, the battery device being used to store electrical energy.

[0052] The following description is further illustrated with specific embodiments and comparative examples. Unless otherwise specified, the raw materials involved in the following specific embodiments and comparative examples are all commercially available. Unless otherwise specified, the instruments used are all commercially available. Unless otherwise specified, the processes involved are conventionally selected by those skilled in the art.

[0053] Example 1

[0054] This embodiment provides a solid-state battery and its preparation method, the steps of which are as follows:

[0055] Step 1: Pretreatment of nickel foam: Take nickel foam with a thickness of 100μm and a pore size of 300μm, and clean it by ultrasonication in acetone, alcohol and deionized water in sequence, and then dry it for later use.

[0056] Step 2: Electrochemical deposition of ZnO nanopillars: Nickel foam was used as the working electrode, a platinum sheet as the counter electrode, and a silver / silver chloride electrode as the reference electrode. A mixed solution of Zn(NO3)2 and NH4NO3 was used as the electrodeposition solution, with a Zn(NO3)2 concentration of 0.05 mol / L and a Zn(NO3)2 to NH4NO3 molar ratio of 1:5. The deposition was carried out at a current density of 0.5 mA / cm². 2Electrodeposition was performed at a temperature of 30℃ for 20 min, depositing an array of zinc oxide nanopillars on the surface of nickel foam to obtain a current collector. SEM characterization showed that the zinc oxide nanopillars were distributed in a discontinuous array on the nickel foam surface, with the ratio of their projected area on the nickel foam surface to the total area of ​​the nickel foam surface ranging from 75% to 85%.

[0057] Step 3: Preparation of positive electrode sheet: Mix LFP:PVDF:conductive carbon black in a mass ratio of 8:1:1, then add water to prepare positive electrode slurry. Use a scraper to coat the positive electrode slurry onto the side of the current collector obtained in Step 2 where the zinc oxide nanopillar array is deposited. Dry under vacuum at 120°C to form the positive electrode active layer and obtain the positive electrode sheet.

[0058] Step 4: Preparation of negative electrode sheet: Mix the graphite:conductive carbon black:CMC+SBR composite system at a mass ratio of 8:1:1, then add water to prepare negative electrode slurry. Use a scraper to coat the negative electrode slurry onto the side of the current collector obtained in step 2 that has the zinc oxide nanopillar array deposited on it, and vacuum dry at 120℃ to form the negative electrode active layer, thus obtaining the negative electrode sheet.

[0059] Step 5: Solid electrolyte preparation: Lithium sulfide (Li₂S), phosphorus pentasulfide (P₂S₅), and LiCl powders with a purity higher than 99.9% were placed in an agate ball mill jar. Under argon protection, high-energy ball milling was performed at 300–600 rpm for 10–30 hours. The glassy powder was transferred to an alumina crucible and annealed in an argon-atmosphere tube furnace at 200–300 °C for 1–5 hours, with a heating rate of 5 °C / min (slow heating to avoid powder agglomeration). After annealing, the furnace was cooled to room temperature to obtain the Li₆PS₅Cl sulfide electrolyte.

[0060] Step Six: Solid Electrolyte Injection: Assemble the positive and negative electrode sheets according to the battery structure. Under vacuum conditions, use ultrasonic oscillation (frequency 40kHz) + stepped pressurization (0min~5min, pressure 0.1MPa; 5min~15min, pressure 3MPa; 15min~25min, pressure 10MPa) to inject an electrolyte precursor solution between the positive and negative electrode sheets. This allows the electrolyte precursor solution to permeate through the zinc oxide nanopillar array into the pores of the nickel foam. The electrolyte precursor solution includes the Li6PS5Cl sulfide electrolyte (10wt%) obtained in Step Five and a PAN polymer solution (NMP solvent). After vacuum injection, hot-press (80℃, 10MPa, 30min) to form a solid electrolyte with a continuous ion / electron dual-pathway network located between the positive and negative electrode sheets.

[0061] Example 2

[0062] This embodiment provides a solid-state battery and its preparation method, the steps of which are as follows:

[0063] Step 1, Nickel foam pretreatment: Same as in Example 1.

[0064] Step 2: Electrochemical deposition of ZnO nanopillars: Nickel foam was used as the working electrode, a platinum sheet as the counter electrode, and a silver / silver chloride electrode as the reference electrode. A mixed solution of Zn(NO3)2 and NH4NO3 was used as the electrodeposition solution, with a Zn(NO3)2 concentration of 0.1 mol / L and a Zn(NO3)2 to NH4NO3 molar ratio of 1:8. The deposition was carried out at a current density of 1 mA / cm². 2 Electrodeposition was carried out at a temperature of 50°C for 20 minutes to deposit a zinc oxide nanopillar array on the surface of nickel foam, thus obtaining a current collector.

[0065] Step 3: Prepare the positive electrode sheet: Same as in Example 1.

[0066] Step 4: Prepare the negative electrode sheet: Same as in Example 1.

[0067] Step 5: Preparation of solid electrolyte: Same as in Example 1.

[0068] Step 6: Solid electrolyte infusion: Same as in Example 1.

[0069] Example 3

[0070] This embodiment provides a solid-state battery and its preparation method, the steps of which are as follows:

[0071] Step 1, Nickel foam pretreatment: Same as in Example 1.

[0072] Step 2: Electrochemical deposition of ZnO nanopillars: Same as in Example 1.

[0073] Step 3: Prepare the positive electrode sheet: Same as in Example 1.

[0074] Step 4: Prepare the negative electrode sheet: Same as in Example 1.

[0075] Step 5: Preparation of solid electrolyte: Same as in Example 1.

[0076] Step Six: Solid Electrolyte Injection: Assemble the positive and negative electrode sheets according to the battery structure. Under vacuum conditions, use ultrasonic oscillation (frequency 20kHz) + stepped pressurization (0min~5min, pressure 0.2MPa; 5min~10min, pressure 5MPa; 10min~25min, pressure 10MPa) to inject an electrolyte precursor solution between the positive and negative electrode sheets. This allows the electrolyte precursor solution to permeate through the zinc oxide nanopillar array into the pores of the nickel foam. The electrolyte precursor solution includes Li6PS5Cl (12wt%) obtained in Step Five and a PAN polymer solution (NMP solvent). After vacuum injection, hot-press (100℃, 10MPa, 20min) to form a solid electrolyte with a continuous ion / electron dual-pathway network located between the positive and negative electrode sheets.

[0077] Comparative Example 1

[0078] This comparative example provides a solid-state battery and its preparation method, the steps of which are as follows:

[0079] Step 1, Nickel foam pretreatment: Same as in Example 1.

[0080] Step 2: Preparation of positive electrode sheet: Mix LFP:PVDF:conductive carbon black in a mass ratio of 8:1:1, then add water to prepare positive electrode slurry. Use a scraper to coat the positive electrode slurry onto the nickel foam obtained in step 1, and vacuum dry at 120℃ to form a positive electrode active layer, thus obtaining the positive electrode sheet.

[0081] Step 3: Preparation of negative electrode sheet: Mix the graphite:conductive carbon black:CMC+SBR composite system at a mass ratio of 8:1:1, then add water to prepare negative electrode slurry. Use a scraper to coat the negative electrode slurry onto the nickel foam obtained in step 1, and vacuum dry at 120℃ to form a negative electrode active layer, thus obtaining the negative electrode sheet.

[0082] Step 4: Preparation of solid electrolyte: Same as in Example 1.

[0083] Step 5: Solid electrolyte infusion: Same as in Example 1.

[0084] Comparative Example 2

[0085] This comparative example provides a solid-state battery and its preparation method, the steps of which are as follows:

[0086] Step 1, Nickel foam pretreatment: Same as in Example 1.

[0087] Step 2: Electrochemical deposition of ZnO nanopillars: 29.7 mg of zinc nitrate (Zn(NO3)2·6H2O) and 5.3 mg of dimethylamine borane were dissolved in 10 mL of ultrapure water and magnetically stirred at room temperature for 10 minutes to obtain a mixed solution. Nickel foam was immersed in the above mixed solution and subjected to a hydrothermal reaction at 80 °C for 2 h. After the reaction, the product was rinsed once with deionized water, then once with ethanol, and dried in an oven at 60 °C for 6 h, resulting in the deposition of a zinc oxide film on the surface of the nickel foam, thus obtaining a current collector. SEM characterization showed that the zinc oxide film was continuously distributed on the surface of the nickel foam.

[0088] Step 3: Prepare the positive electrode sheet: Same as in Example 1.

[0089] Step 4: Prepare the negative electrode sheet: Same as in Example 1.

[0090] Step 5: Preparation of solid electrolyte: Same as in Example 1.

[0091] Step 6: Solid electrolyte infusion: Same as in Example 1.

[0092] Performance tests were conducted on the solid-state batteries of the above embodiments and comparative examples. The test items and results are as follows:

[0093] Project 1: Ratio Performance Test

[0094] Test environment: 25℃ constant temperature chamber

[0095] Test process:

[0096] 1. Charge at a constant current of 0.1C to 3.6V (cutoff current 0.01C), and let stand for 30 minutes;

[0097] 2. Discharge to 2.0V at constant currents of 0.2C, 0.5C, 1C, 2C, and 5C respectively, and let stand for 30 minutes after each discharge;

[0098] 3. Repeat each discharge rate 3 times, and take the second discharge capacity as the effective capacity at that rate;

[0099] 4. Calculate the ratio of each rate capacity to the 0.2C capacity (i.e., the rate capacity retention rate), and the results are shown in Table 1.

[0100] Project 2: Cyclic Stability Test

[0101] Test environment: 25℃ constant temperature chamber

[0102] Test process:

[0103] 1. Charge at a constant current of 0.5C to 3.6V (cutoff current 0.01C), and let stand for 10 minutes;

[0104] 2. Discharge at a constant current of 0.5C to 2.0V, and let stand for 10 minutes;

[0105] 3. Repeat the above charge-discharge cycle and record the discharge capacity for each cycle;

[0106] 4. Calculate the capacity retention rate (capacity after 500 cycles / initial capacity × 100%) and the internal resistance growth rate ((internal resistance after 500 cycles - initial internal resistance) / initial internal resistance × 100%) after 500 cycles. The results are shown in Table 2.

[0107] Project 3: Cyclic Life Test

[0108] Test environment: 45℃ constant temperature chamber

[0109] Test process:

[0110] 1. Charge at a constant current of 1C to 3.6V (cutoff current 0.01C), and let stand for 10 minutes;

[0111] 2. Discharge at a constant current of 1C to 2.0V, and let stand for 10 minutes;

[0112] 3. Continue cycling until the discharge capacity drops to 80% of the initial capacity, and record the number of cycles at this point (defined as cycle life). See Table 3 for the results.

[0113] Table 1

[0114]

[0115] Table 2

[0116]

[0117] Table 3

[0118]

[0119] The results show that after forming oxide arrays on the surface of porous current collectors in Examples 1 to 3, the resulting current collectors can improve the wetting of the solid electrolyte onto the electrode sheets, optimize the ion conduction path, significantly reduce polarization during high-rate charging, and improve battery rate performance and cycle stability. Simultaneously, the oxide array configuration can also improve the adhesion between the electrode active layer and the electrode current collector, avoiding the problem of delamination at the current collector interface caused by large volume changes in the electrode active material during solid-state battery charging and discharging, thus improving cycle life. Comparing Example 1 with Comparative Example 1, Comparative Example 1 directly forms the positive electrode active layer on nickel foam, resulting in poor wettability of the solid electrolyte onto the electrode sheets, increased polarization at high rates, rapid capacity decline, decreased capacity retention after cycling, increased internal resistance, and decreased cycle life. Comparing Example 1 with Comparative Example 2, Comparative Example 2 uses a hydrothermal method to deposit a continuous zinc oxide film, which hinders the penetration of the electrolyte into the pores of the nickel foam, leading to limited ion transport and poor performance at high rates and during cycling.

[0120] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0121] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A solid-state battery, characterized in that, It includes a positive electrode, a negative electrode, and a solid electrolyte located between the positive electrode and the negative electrode; The positive electrode includes a positive current collector and a positive active layer on top of the positive current collector; the positive current collector includes a first porous current collector and a first oxide array on the surface of the first porous current collector; and / or, The negative electrode sheet includes a negative current collector and a negative active layer located on the negative current collector. The negative current collector includes a second porous current collector and a second oxide array located on the surface of the second porous current collector.

2. The solid-state battery according to claim 1, characterized in that, The solid electrolyte permeates through the first oxide array into the pores of the first porous current collector; and / or, The solid electrolyte permeates through the second oxide array into the pores of the second porous current collector.

3. The solid-state battery according to claim 1, characterized in that, Includes at least one of the following features: (1) The first oxide array includes first oxide pillars arranged in an array, and the material of each first oxide pillar independently includes at least one of zinc oxide, aluminum oxide, lithium oxide and titanium oxide; (2) The first oxide array is located on the surface of the first porous current collector, and the total area of ​​the orthographic projection of the first oxide array on the surface accounts for 75% to 85% of the area of ​​the surface; (3) The second oxide array includes second oxide pillars arranged in an array, and the material of each second oxide pillar independently includes at least one of zinc oxide, aluminum oxide, lithium oxide and titanium oxide; (4) The second oxide array is located on the surface of the second porous current collector, and the total area of ​​the orthographic projection of the second oxide array on the surface accounts for 75% to 85% of the area of ​​the surface.

4. The solid-state battery according to claim 1, characterized in that, Includes at least one of the following features: (1) The first porous current collector includes at least one of foamed nickel, porous stainless steel, metal foil composite porous carbon layer and porous carbon fiber product; (2) The pore size of the first porous current collector is 200μm~400μm; (3) The second porous current collector includes at least one of foamed nickel, porous stainless steel, metal foil composite porous carbon layer and porous carbon fiber product; (4) The pore size of the second porous current collector is 200μm~400μm.

5. The solid-state battery according to claim 1, characterized in that, The solid electrolyte includes sulfide electrolytes and polyacrylonitrile electrolytes.

6. The solid-state battery according to any one of claims 1 to 5, characterized in that, Includes at least one of the following features: (1) The positive electrode active layer includes a positive electrode active material, a binder and a conductive agent, wherein the positive electrode active material includes lithium iron phosphate; (2) The negative electrode active layer includes a negative electrode active material, a binder and a conductive agent, wherein the negative electrode active material includes graphite, silicon-based composite material or lithium titanate.

7. A method for preparing a solid-state battery, characterized in that, Includes the following steps: A method for preparing a positive electrode and / or a negative electrode includes the following steps: forming a first oxide array on the surface of a first porous current collector to prepare a positive current collector; forming a positive active layer on one side of the first oxide array of the positive current collector to prepare a positive electrode; and a method for preparing a negative electrode includes the following steps: forming a second oxide array on the surface of a second porous current collector to prepare a negative current collector; and forming a negative active layer on one side of the second oxide array of the negative current collector to prepare a negative electrode. The positive and negative electrode sheets are assembled according to the battery structure, and an electrolyte precursor solution is injected between the positive and negative electrode sheets. The mixture is then hot-pressed to form a solid electrolyte located between the positive and negative electrode sheets.

8. The method for preparing a solid-state battery according to claim 7, characterized in that, After the electrolyte precursor solution is injected between the positive electrode and the negative electrode, the method further includes the following steps: applying ultrasound and pressure to the battery structure injected with the electrolyte precursor solution, so that the electrolyte precursor solution permeates through the first oxide array into the pores of the first porous current collector; and / or so that the electrolyte precursor solution permeates through the second oxide array into the pores of the second porous current collector.

9. The method for preparing a solid-state battery according to claim 8, characterized in that, Includes at least one of the following features: (1) The frequency of the ultrasound is 20kHz~50kHz; (2) Apply pressure according to the following procedure: 0 min to 5 min, pressure is 0.08 MPa to 0.22 MPa; 5 min to 10 min, pressure is 2.5 MPa to 5.5 MPa; 10 min to 15 min, pressure is 2.5 MPa to 10.5 MPa; 15 min to 25 min, pressure is 9 MPa to 11 MPa.

10. The method for preparing a solid-state battery according to claim 7, characterized in that, The methods for depositing a first oxide array on the surface of the first porous current collector and for depositing a second oxide array on the surface of the second porous current collector each independently include an electrochemical deposition method.

11. The method for preparing a solid-state battery according to claim 10, characterized in that, Includes at least one of the following features: (1) Depositing a first oxide array on the surface of the first porous current collector includes the following steps: inserting a three-electrode system A into a first electrodeposition solution to perform a first electrochemical deposition, wherein the working electrode in the three-electrode system A is the first porous current collector, and the first electrodeposition solution includes a first metal salt; (2) Depositing a second oxide array on the surface of the second porous current collector includes the following steps: inserting a three-electrode system B into a second electrode deposition solution to perform a second electrochemical deposition, wherein the working electrode in the three-electrode system B is the second porous current collector, and the second electrode deposition solution includes a second metal salt.

12. The method for preparing a solid-state battery according to claim 11, characterized in that, Includes at least one of the following features: (1) The counter electrodes of the three-electrode system A and the three-electrode system B are each independently selected from platinum sheets; (2) The reference electrodes of the three-electrode system A and the three-electrode system B are each independently selected from silver / silver chloride electrodes; (3) The first metal salt and the second metal salt each independently include at least one of zinc salt, aluminum salt, lithium salt and titanium salt; (4) The concentration of the first metal salt in the first electrodeposition solution is 0.01 mol / L to 0.1 mol / L; (5) The concentration of the second metal salt in the second electrodeposition solution is 0.01 mol / L to 0.1 mol / L; (6) The first electrodeposition solution and the second electrodeposition solution each independently further include a conductive salt, wherein the conductive salt includes an ammonium salt; (7) The current density of the first electrochemical deposition and the second electrochemical deposition is independently 0.1 mA / cm². 2 ~1mA / cm 2 ; (8) The ambient temperatures for the first and second electrochemical depositions are each independently 20°C to 50°C; (9) The deposition time of the first electrochemical deposition and the second electrochemical deposition are each 10 min to 30 min independently.

13. The method for preparing a solid-state battery according to any one of claims 7 to 12, characterized in that, Includes at least one of the following features: (1) The electrolyte precursor solution includes sulfide electrolyte and polyacrylonitrile electrolyte; (2) The solvent of the electrolyte precursor solution includes N-methylpyrrolidone.

14. A battery device, characterized in that, The solid-state battery includes any one of claims 1 to 6, or any solid-state battery prepared by any one of claims 7 to 13.

15. An electrical appliance, characterized in that, Includes the battery device of claim 14, the battery device being used to provide electrical energy.

16. An energy storage device, characterized in that, Includes the battery device of claim 14, the battery device being used for storing electrical energy.

Images