Plastic current collector, positive electrode, negative electrode and solid-state battery

Abstract

The embodiment of the invention provides a plastic current collector, a positive electrode, a negative electrode and a solid-state battery. The plastic current collector comprises a rubber composite layer and metal sputtering layers deposited on the two sides of the rubber composite layer. Wherein the rubber composite layer comprises an insulating filler and a rubber material. According to the technical scheme, the impedance increase in the circulation process and the external pressure of the all-solid-state battery are reduced, the cell polarization speed and the capacity attenuation speed of the solid-state battery are reduced, the interface contact state is collaboratively optimized, and the loading popularization of the all-solid-state battery is more facilitated.

Description

Technical Field

[0001] This application relates to the field of battery technology, and more particularly to a plastic current collector, a positive electrode, a negative electrode, and a solid-state battery. Background Technology

[0002] All-solid-state lithium-ion batteries have abandoned the flammable and volatile organic liquid electrolytes used in traditional lithium-ion batteries, and instead use highly stable inorganic solid electrolytes, thus eliminating the risks of electrolyte leakage, decomposition and thermal runaway from the source, and have received widespread attention from the scientific research and industry communities.

[0003] Currently, considering that inorganic solid electrolytes have a higher density than liquid electrolytes, the energy density of all-solid-state lithium-ion batteries using the same positive and negative electrode systems is lower than that of liquid lithium-ion batteries. Therefore, using a positive electrode with high nickel content and a negative electrode with higher capacity (silicon, lithium) is the core key to achieving high-energy-density all-solid-state batteries.

[0004] However, high-nickel cathodes cause anisotropic volume changes, while the volume of the anode expands by up to 300% after lithium intercalation. The lithium metal anode also undergoes huge volume expansion during the lithium deposition process during charging, which in turn leads to increased cell polarization and capacity decay in solid-state batteries. Summary of the Invention

[0005] This application provides a plastic current collector, a positive electrode, a negative electrode, and a solid-state battery to achieve the technical effect of reducing the rate of cell polarization and capacity decay in solid-state batteries.

[0006] In a first aspect, embodiments of this application provide a plastic current collector, comprising:

[0007] A rubber composite layer and a metal sputtered layer deposited on both sides of the rubber composite layer;

[0008] The rubber composite layer includes insulating fillers and rubber materials.

[0009] In one possible implementation, the insulating filler comprises at least one of fibrous resin, resin-based nonwoven fabric, alumina, magnesium oxide, boehmite, and silica.

[0010] In one possible implementation, the rubber material includes at least one of silicone rubber, natural rubber, polyvinyl chloride, nitrile rubber, hydrogenated nitrile rubber, styrene-butadiene rubber, isoprene rubber, and cis-butadiene rubber.

[0011] In one possible implementation, the metal sputtered layer comprises any one of the following metallic materials: aluminum, copper, nickel, titanium, or steel.

[0012] In one possible implementation, the thickness of the plastic current collector is 8-100 micrometers, and / or the thickness of the rubber composite layer is 6-96 micrometers, and / or the thickness of the metal sputtering layer is 200-2000 nanometers.

[0013] Secondly, embodiments of this application provide a method for preparing a plastic current collector, the method being used to prepare a plastic current collector as shown in the first aspect and / or various possible implementations of the first aspect, the method comprising:

[0014] The rubber material is dispersed in a solvent to obtain a dispersion solution;

[0015] An insulating filler is added to the dispersion to obtain a mixed solution;

[0016] The mixed solution is coated and dried to obtain a rubber composite layer;

[0017] Metal material is uniformly deposited on both sides of the rubber composite layer to form a metal sputtering layer on both sides of the rubber composite layer, thereby obtaining a plastic current collector.

[0018] In one possible implementation, the solid content of the mixed solution is 40-60%.

[0019] In one possible implementation, the solvent includes at least one of toluene, xylene, butyl butyrate, and n-alkanes.

[0020] In one possible implementation, the uniform deposition of the metal material on both sides of the rubber composite layer includes:

[0021] The metal material is uniformly deposited on both sides of the rubber composite layer by any of the following methods: resistance evaporation, telemetry sputtering, or electron gun evaporation.

[0022] Thirdly, embodiments of this application provide a positive electrode, including a plastic current collector and a positive electrode coating coated on at least one side of the plastic current collector;

[0023] The plastic current collector is a plastic current collector as shown in the first aspect and / or various possible implementations of the first aspect above, or a plastic current collector prepared by the preparation method shown in the second aspect and / or various possible implementations of the second aspect.

[0024] Fourthly, embodiments of this application provide a negative electrode, including a plastic current collector and a negative electrode coating coated on at least one side of the plastic current collector;

[0025] The plastic current collector is a plastic current collector as shown in the first aspect and / or various possible implementations of the first aspect above, or a plastic current collector prepared by the preparation method shown in the second aspect and / or various possible implementations of the second aspect.

[0026] Fifthly, embodiments of this application provide a solid-state battery, including a positive electrode as shown in the third aspect above, a negative electrode as shown in the fourth aspect above, and an electrolyte.

[0027] This application provides a plastic current collector, a positive electrode, a negative electrode, and a solid-state battery. The plastic current collector includes a rubber composite layer and metal sputtered layers deposited on both sides of the rubber composite layer. The rubber composite layer includes an insulating filler and a rubber material. In this technical solution, because the rubber composite layer itself is elastic, it can provide elastic space when the electrode active material expands and rebound to maintain close contact when contracting, thereby ensuring sufficient contact between the negative electrode and the electrolyte layer, as well as between the positive electrode and the electrolyte layer. This reduces the increase in impedance during cycling and the external pressure on the all-solid-state battery, and also reduces the rate of cell polarization and capacity decay in the solid-state battery. Simultaneously, the strength of the rubber composite layer can be controlled by the insulating filler, and the insulating filler forms fine irregularities on the surface of the rubber composite layer, increasing the bonding between the rubber composite layer and the metal sputtered layer, further optimizing the interface contact state, which is more conducive to the promotion and application of all-solid-state batteries in vehicles. Attached Figure Description

[0028] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0029] Figure 1 This is a schematic diagram of the structure of the plastic current collector provided in an embodiment of this application;

[0030] Figure 2 This is a schematic flowchart illustrating the preparation method of the plastic current collector provided in the embodiments of this application.

[0031] Explanation of reference numerals in the attached figures:

[0032] 1-Rubber composite layer;

[0033] 11-Insulating filler;

[0034] 2-Metal sputtering layer.

[0035] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0036] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0037] First, the application scenarios involved in this application will be explained:

[0038] All-solid-state lithium-ion batteries eliminate the flammable and volatile organic liquid electrolytes used in traditional lithium-ion batteries, instead employing highly stable inorganic solid electrolytes. This fundamental replacement eliminates the risks of electrolyte leakage, decomposition, and thermal runaway at the source, bringing revolutionary safety improvements to battery systems. This significantly expands their application prospects in fields with extremely stringent safety requirements, such as electric vehicles and large-scale energy storage, and has therefore garnered sustained high attention and investment from academia and industry, becoming a revolutionary direction for next-generation energy storage technology.

[0039] However, while pursuing safety, all-solid-state batteries also face significant technological challenges. A key bottleneck lies in energy density. Although inorganic solid-state electrolyte materials (such as sulfides and oxides) possess excellent thermal stability and mechanical strength, their density is generally significantly higher than that of their organic electrolyte counterparts. Simultaneously, to achieve sufficient ionic conductivity and ensure good contact at the electrode / electrolyte interface, the solid-state electrolyte layer often needs to reach a certain thickness. These factors combined mean that when using the same cathode (such as lithium cobalt oxide or lithium iron phosphate) and anode (such as graphite) material systems as existing liquid batteries, the energy stored per unit volume or per unit mass (energy density) of all-solid-state batteries is typically difficult to match that of mature liquid lithium-ion battery technology.

[0040] To bridge this energy density gap and achieve a true leap forward in energy storage performance for all-solid-state batteries, innovative upgrades to the material system are inevitable. Improvements are primarily focused on both the positive and negative electrodes. On the positive electrode side, developing and applying layered oxide materials with high nickel content is the core strategy. These materials can provide a higher discharge voltage platform and a larger reversible specific capacity, significantly enhancing the contribution of the positive electrode. On the negative electrode side, breaking through the theoretical capacity limit of traditional graphite is crucial. Actively developing and adopting novel negative electrode materials with higher specific capacity is key. For example, silicon-based negative electrodes (silicon-carbon, silicon-oxygen composites) have great potential due to their theoretical capacity being several times that of graphite, or they may represent a more radical future lithium metal negative electrode solution.

[0041] However, while high-nickel cathodes offer higher capacity, the continuous increase in nickel content exacerbates anisotropic volume changes during charge and discharge. This uneven deformation not only impairs the material's structural stability but also directly leads to a significant decrease in battery cycle life and fast charge / discharge (rate) performance. On the anode side, silicon-based materials (theoretical specific capacity approximately 4200 mAh / g) and lithium metal anodes (theoretical specific capacity 3860 mAh / g) are ideal choices for constructing high-energy-density all-solid-state batteries due to their enormous capacity potential. However, both types of materials face a common and severe interfacial challenge: silicon anodes experience volume expansion of up to 300% during lithium intercalation, while lithium metal anodes also undergo significant volume changes during charging (deposition). After repeated volume expansion and contraction, the physical contact between the all-solid-state battery and the solid electrolyte inevitably deteriorates or even detaches. This interfacial contact failure directly leads to a sharp increase in lithium-ion transport resistance (polarization) at the interface, manifested as rapid capacity decay and performance degradation. This core issue of interfacial mechanical stability has become a key bottleneck restricting the synergistic development of high energy density and long cycle life in all-solid-state batteries based on high-nickel cathodes and high-capacity silicon / lithium metal anode systems.

[0042] In other words, both the positive and negative electrodes of existing solid-state batteries experience volume expansion during the charging process, which in turn increases the polarization of the solid-state battery cells and the rate of capacity decay.

[0043] Based on the aforementioned technical problems, the technical concept of this application is as follows: Traditional rigid current collectors cannot adapt to the dynamic deformation of electrode materials, thus exacerbating the severe anisotropic expansion of the high-nickel cathode and the significant volume change of the silicon / lithium metal anode in all-solid-state batteries. Therefore, the inventors conceived of using a malleable current collector to replace the traditional rigid current collector. This malleable current collector includes a rubber composite layer and metal sputtered layers deposited on both sides of the rubber composite layer. The rubber composite layer can contract under pressure during charging and expand after pressure release during discharging, effectively mitigating contact loss and increased polarization caused by volume changes. Furthermore, the rubber composite layer includes insulating fillers, and its strength can be adjusted according to actual needs, further reducing the cell polarization and capacity decay rate of the solid-state battery.

[0044] The technical solution of this application and how the technical solution of this application solves the above-mentioned technical problems are described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this application will now be described with reference to the accompanying drawings.

[0045] First, we will explain the structure and composition of the plastic current collector in detail.

[0046] Figure 1 This is a schematic diagram of the structure of a plastic current collector provided in an embodiment of this application. Figure 1 As shown, the plastic current collector includes a rubber composite layer 1 and a metal sputtering layer 2 deposited on both sides of the rubber composite layer 1.

[0047] The rubber composite layer 1 includes an insulating filler 11 (black dots) and rubber material.

[0048] The thickness of the plastic current collector is 8-100 micrometers.

[0049] Specifically, the insulating filler 11 includes at least one of fibrous resin, resin-based nonwoven fabric, alumina, magnesium oxide, boehmite, and silica.

[0050] Optionally, the content of insulating filler 11 in rubber composite layer 1 is 10-40%.

[0051] Specifically, the rubber materials include at least one of silicone rubber, natural rubber, polyvinyl chloride, nitrile rubber, hydrogenated nitrile rubber, styrene-butadiene rubber, isoprene rubber, and cis-butadiene rubber.

[0052] Optionally, the content of rubber material in rubber composite layer 1 is 60-90%.

[0053] It should be understood that the sum of the content of insulating filler 11 in rubber composite layer 1 and the content of rubber material in rubber composite layer 1 is 100%.

[0054] The thickness of the rubber composite layer 1 is 6-96 micrometers.

[0055] Specifically, the metal sputtering layer 2 includes any one of the following metal materials: aluminum, copper, nickel, titanium, or steel.

[0056] The thickness of the metal sputtering layer 2 is 200-2000 nanometers.

[0057] The plastic current collector provided in this application includes a rubber composite layer and metal sputtered layers deposited on both sides of the rubber composite layer. The rubber composite layer includes an insulating filler and a rubber material. In this technical solution, because the rubber composite layer itself is elastic, it can provide elastic space when the electrode active material expands and rebound to maintain close contact when contracting, thereby ensuring sufficient contact between the negative electrode and the electrolyte layer, as well as between the positive electrode and the electrolyte layer. This reduces the increase in impedance during cycling and the external pressure on the all-solid-state battery, and also reduces the rate of cell polarization and capacity decay in the solid-state battery. Simultaneously, the strength of the rubber composite layer can be controlled by the insulating filler in the rubber composite layer, and the insulating filler forms tiny bumps and depressions on the surface of the rubber composite layer, increasing the bonding between the rubber composite layer and the metal sputtered layer, further synergistically optimizing the interface contact state, which is more conducive to the promotion and application of all-solid-state batteries in vehicles.

[0058] Figure 2 This is a schematic flowchart illustrating the preparation method of the plastic current collector provided in an embodiment of this application. Figure 2 As shown, the preparation method of this plastic current collector can be achieved through the following steps:

[0059] S21. Disperse the rubber material in a solvent to obtain a dispersion solution.

[0060] The solvent includes at least one of toluene, xylene, butyl butyrate, and n-alkanes.

[0061] In one possible implementation, the rubber material can be first cut to a preset size, and then the rubber material of the preset size can be immersed in a solvent to swell and soften, obtaining an initial dispersion. Next, the initial dispersion is placed in a planetary mixer for medium-low speed stirring to dissolve and disperse the rubber material in the solvent, thereby obtaining a uniformly dispersed rubber material dispersion.

[0062] In another possible implementation, after the initial dispersion solution is placed in a planetary mixer for medium-low speed stirring, the stirred solution can be further subjected to intensive processing by a three-roll mill or a high-speed shearing device to ensure that the rubber material is fully dispersed in the solvent, thereby obtaining a dispersion solution.

[0063] S22. Add the insulating filler to the dispersion solution to obtain a mixed solution.

[0064] The solid content of the mixed solution is 40-60%.

[0065] It should be understood that the solid content of the mixed solution affects the strength of the rubber composite layer.

[0066] In one possible implementation, the insulating filler is first dried, then the dispersion is stirred at low speed, and the dried insulating filler is added gradually in batches during the stirring process. After each batch is added, stirring continues until no obvious powder floats before adding the next batch, to avoid agglomeration caused by instantaneous overload of the insulating filler. After all the dried insulating filler has been added, an initial mixed solution is obtained, which is then subjected to high-speed shear dispersion, followed by cyclic grinding using a three-roll mill to finally obtain the final mixed solution.

[0067] S23. The mixed solution is coated and dried to obtain a rubber composite layer.

[0068] Alternatively, coating can be achieved through methods such as transfer, extrusion, and spraying.

[0069] In one possible implementation, the amount of mixed solution transferred is controlled by utilizing the gap between the metering roller and the transfer roller of the coating machine. The mixed solution is uniformly transferred to the surface of the base film by the counter-rotating coating roller to form an initial wet film.

[0070] In another possible implementation, the mixed solution is pumped into a slit extrusion die, and the wet film thickness is controlled by adjusting the die lip gap and the base film travel speed, so that the mixed solution flows out in a stable curtain shape and covers the moving base film to form an initial wet film.

[0071] In another possible implementation, a high-precision spray gun is used to atomize the mixed solution, and a programmed moving path is used to deposit it layer by layer on the base film to the target thickness to form an initial wet film.

[0072] Based on the three methods described above, the initial wet film can be dried to obtain a rubber composite layer. Specifically, the initial wet film can be dried at 40-60°C. The high-temperature air knife rapid drying zone utilizes directional high-speed airflow (8-12 m / s) to achieve solvent flash evaporation, rapidly removing over 70% of volatile components and effectively suppressing the deformation of the initial wet film. Afterwards, it is transferred to a 60-80°C zone. In the isothermal homogenization zone, a transverse turbulent circulation air system is used to uniformly remove residual solvent, avoiding micro-area curling caused by localized drying stress. Finally, at 80-100... The thermal cross-linking curing zone is maintained for 10-20 minutes to obtain the rubber composite layer.

[0073] S24. Metal material is uniformly deposited on both sides of the rubber composite layer to form a metal sputtering layer on both sides of the rubber composite layer, thus obtaining a plastic current collector.

[0074] In one possible implementation, the metallic material is uniformly deposited on both sides of the rubber composite layer by any of the following methods: resistive evaporation, telemetry sputtering, or electron gun evaporation.

[0075] Resistance evaporation: In a high-vacuum chamber, a metallic material is wound around a tungsten heating boat. The boat is then energized and heated to the vaporization point of the metallic material, causing the metal vapor to condense and deposit on the surface of the rubber composite layer. Specifically, a planetary rotating frame ensures uniform coverage on both sides of the rubber composite layer, and the final thickness is monitored online to 200-2000 nanometers using a quartz crystal oscillator. Throughout the process, the temperature of the rubber composite layer is controlled to be ≤50°C. This prevents the rubber composite layer from thermally degrading.

[0076] Measurement and control sputtering: Argon gas is introduced into the dual-target symmetric sputtering system to maintain the working pressure. Then, an RF power supply or a DC pulse power supply is applied to excite the plasma, so that argon ions bombard sputtered atoms of the metal material. The rubber composite layer is placed on a continuously rotating conveyor belt and controlled to traverse the dual-target region, achieving alternating deposition on both sides through baffle timing control.

[0077] Electron gun evaporation: The metal material is placed in a water-cooled copper crucible and heated by focused electron beam to vaporize it instantaneously, which then condenses into a film on the surface of the rubber composite layer. The rubber composite layer is fixed on a three-dimensional oscillating fixture, and the deposition chamber is equipped with an ion-assisted source to enhance the film density.

[0078] This application provides a method for preparing a plastic current collector. The method involves dispersing a rubber material in a solvent to obtain a dispersion solution. An insulating filler is then added to the dispersion solution to obtain a mixed solution. The mixed solution is then coated and dried to obtain a rubber composite layer. Finally, a metal material is uniformly deposited on both sides of the rubber composite layer to form a metal sputtering layer on both sides, resulting in a plastic current collector. In this technical solution, the plastic current collector prepared by this method can dynamically adapt to repeated volume changes of the electrode material, effectively suppressing contact failure at the electrode / electrolyte interface in all-solid-state batteries, significantly reducing polarization and improving cycle life. Simultaneously, the introduction of the insulating filler can precisely control the mechanical strength of the electrode, improving the safety, lifespan, and interface stability of high-energy-density all-solid-state batteries.

[0079] Optionally, embodiments of this application also provide a positive electrode, which includes a plastic current collector and a positive electrode coating coated on at least one side of the plastic current collector.

[0080] Among them, the plastic current collector is Figure 1 The plastic current collector in the illustrated embodiment, or by means of Figure 2 The plastic current collector is prepared by the method of preparing the plastic current collector in the embodiment shown.

[0081] It should be understood that the positive electrode coating may include at least one of NCM811, carbon black, carbon nanotubes, Li3YCl6, and polytetrafluoroethylene.

[0082] For example, the thickness of the positive electrode coating is 100 micrometers.

[0083] Optionally, embodiments of this application also provide a negative electrode, which includes a plastic current collector and a negative electrode coating coated on at least one side of the plastic current collector;

[0084] Among them, the plastic current collector is Figure 1 The plastic current collector in the illustrated embodiment, or by means of Figure 2 The plastic current collector is prepared by the method of preparing the plastic current collector in the embodiment shown.

[0085] It should be understood that the negative electrode coating may include at least one of nano-silicon, carbon nanotubes, and polyacrylic acid.

[0086] For example, the thickness of the negative electrode coating is 40 micrometers.

[0087] Optionally, embodiments of this application also provide a solid-state battery, including the above-described positive electrode, the above-described negative electrode, and an electrolyte.

[0088] The electrolyte may include Li3PS4 and / or polytetrafluoroethylene.

[0089] For example, the thickness of the electrolyte is 20 micrometers.

[0090] The technical effects of this application will be illustrated below through several embodiments and comparative examples.

[0091] Example 1

[0092] (1) Preparation of a plastic current collector for the positive electrode

[0093] Step 1: Disperse the nitrile rubber in xylene solvent to form a uniformly dispersed dispersion.

[0094] Step 2: Add boehmite and resin-based nonwoven fabric in a mass ratio of 2:8 to the above dispersion solution to form a mixed solution.

[0095] The solid content is 50%, and the insulating filler accounts for 20% of the mass of the rubber solution.

[0096] Step 3: Coat the mixed solution to prepare an 8-micron rubber composite layer.

[0097] Step 4: Metallic aluminum is deposited on both sides of the rubber composite layer by resistance evaporation to prepare a plastic current collector.

[0098] The metal sputtering layer has a coating thickness of 2 micrometers, and the plastic current collector has a thickness of 10 micrometers.

[0099] (2) Preparation of a plastic current collector for the negative electrode

[0100] Step 1: Disperse the nitrile rubber in xylene solvent to form a uniformly dispersed dispersion.

[0101] Step 2: Add boehmite and resin-based nonwoven fabric in a mass ratio of 2:8 to the above dispersion solution to form a mixed solution.

[0102] The solid content is 50%, and the insulating filler accounts for 20% of the mass of the rubber solution.

[0103] Step 3: Coat the mixed solution to prepare a rubber composite layer with a thickness of 50 micrometers.

[0104] Step 4: Copper metal is deposited on both sides of the rubber composite layer by resistance evaporation to prepare a plastic current collector.

[0105] The metal sputtering layer has a coating thickness of 2 micrometers, and the plastic current collector has a thickness of 52 micrometers.

[0106] (3) Assemble all-solid-state batteries

[0107] Negative electrode: a plastic current collector for the negative electrode and a negative electrode coating applied to at least one side of the plastic current collector for the negative electrode.

[0108] The negative electrode coating consists of nano-silicon, carbon nanotubes, and polyacrylic acid in a mass ratio of 95:2:3, with a thickness of 40 micrometers.

[0109] Electrolyte layer: The mass ratio of Li3PS4 to polytetrafluoroethylene is 99:1, and the thickness is 20 micrometers.

[0110] Positive electrode: a plastic current collector of the positive electrode and a positive electrode coating applied to at least one side of the plastic current collector of the positive electrode.

[0111] The positive electrode coating consists of NCM811, carbon black, carbon nanotubes, Li3YCl6, and polytetrafluoroethylene in a mass ratio of 88.5:1:0.5:8:2, with a thickness of 100 micrometers.

[0112] Cut the positive electrode, negative electrode, and electrolyte layer to the designed size, and stack them in the order of negative electrode-electrolyte layer-positive electrode, at a ratio of 120. The cells are hot-pressed at 0.5 MPa for 60 seconds to obtain bare cells. Then, the bare cells are packaged into a pouch cell and subjected to isostatic pressing at 400 MPa for 3 minutes to form an all-solid-state battery.

[0113] Example 2: The thickness of the rubber composite layer in the plastic current collector of the negative electrode in Example 1 is changed to 30 micrometers.

[0114] Example 3: The thickness of the rubber composite layer in the plastic current collector of the negative electrode in Example 1 was changed to 10 micrometers.

[0115] Example 4: The mass ratio of the insulating filler of the negative electrode to the rubber solution in Example 1 was changed to 10%.

[0116] Example 5: The mass ratio of the insulating filler of the negative electrode to the rubber solution in Example 1 was changed to 30%.

[0117] It should be understood that the preparation processes of the plastic current collector for the positive electrode, the plastic current collector for the positive electrode and the negative electrode, and the assembly process of the all-solid-state battery in Examples 2-5 are the same as those in Example 1.

[0118] Comparative Example

[0119] A 10-micrometer-thick aluminum foil was used as the positive electrode current collector, and an 8-micrometer-thick copper foil was used as the negative electrode current collector. The assembly process of the all-solid-state battery was the same as in Example 1.

[0120] Test case

[0121] Cyclic performance tests were conducted on the all-solid-state batteries in Examples 1-5 and the comparative examples. These tests simulated the repeated charge-discharge processes of all-solid-state batteries in actual use. The performance parameters for the cycle performance tests included cycle life and the rate of increase in impedance per 100 cycles. Cyclic life refers to the number of complete charge-discharge cycles from the first charge-discharge cycle to 80% capacity retention. For example, if the capacity retention is 79.5% after 1200 cycles, then the cycle life is 1200 cycles. The rate of increase in impedance per 100 cycles is the ratio of the direct current resistance (DCR) impedance of the 100th cycle to the DCR impedance of the 1st cycle.

[0122] For example, the performance test results of Examples 1-9 and the comparative examples can be represented by Table 1.

[0123] Table 1 Performance test results of the examples and comparative examples

[0124]

[0125] As shown in Table 1, the cycle life of Examples 1-5 is greater than that of the comparative example, indicating that the solid-state batteries prepared by the plastic current collectors provided in the embodiments of this application have stronger durability than the solid-state batteries in the comparative example. They can withstand more charge-discharge cycles before the capacity decays to 80%, resulting in lower long-term usage costs. The impedance increase rate of Examples 1-5 after 100 cycles is less than that of the comparative example, indicating that the solid-state batteries prepared by the plastic current collectors provided in the embodiments of this application have fewer internal chemical side reactions (such as solid electrolyte interphase (SEI) thickening and lithium deposition), less battery polarization, and slower power performance decay. Compared with the comparative example, the interface contact state is optimized, reducing the problems of electric vehicle heat generation and charging speed reduction.

[0126] As shown in Examples 1-3, as the thickness of the rubber composite layer in the plastic current collector of the negative electrode decreases, the rate of increase in impedance after 100 cycles gradually increases, and the cycle life gradually decreases. This indicates that a thicker rubber composite layer in the plastic current collector of the negative electrode can better mitigate contact loss and increased polarization caused by volume changes, resulting in better solid-state battery performance. As shown in Examples 1, 4, and 5, as the mass ratio of insulating filler to the rubber solution increases, the increase in impedance after 100 cycles first decreases and then increases, while the cycle life first increases and then decreases. This indicates that the solid-state battery performs best when the mass ratio of insulating filler to the rubber solution is changed to 20%.

[0127] Finally, it should be noted that other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This invention is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein, and is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

Claims

1. A plastic current collector, characterized in that, include: A rubber composite layer and a metal sputtered layer deposited on both sides of the rubber composite layer; The rubber composite layer includes insulating filler and rubber material; The rubber composite layer is elastic, providing elastic space when the electrode active material expands, and also rebounding when the electrode active material contracts. The insulating filler is used to regulate the strength of the rubber composite layer, and the insulating filler forms irregularities on the surface of the rubber composite layer to increase the adhesion between the rubber composite layer and the metal sputtering layer.

2. The plastic current collector according to claim 1, characterized in that, The insulating filler includes at least one of fibrous resin, resin-based nonwoven fabric, alumina, magnesium oxide, boehmite, and silica.

3. The plastic current collector according to claim 1 or 2, characterized in that, The rubber material includes at least one of silicone rubber, natural rubber, polyvinyl chloride, nitrile rubber, hydrogenated nitrile rubber, styrene-butadiene rubber, isoprene rubber, and cis-butadiene rubber.

4. The plastic current collector according to claim 1 or 2, characterized in that, The metal sputtered layer includes any one of the following metallic materials: aluminum, copper, nickel, titanium, or steel.

5. The plastic current collector according to claim 1 or 2, characterized in that, The thickness of the plastic current collector is 8-100 micrometers, and / or the thickness of the rubber composite layer is 6-96 micrometers, and / or the thickness of the metal sputtering layer is 200-2000 nanometers.

6. A method for preparing a plastic current collector, characterized in that, The method is used to prepare the plastic current collector as described in any one of claims 1-5, and the method comprises: The rubber material is dispersed in a solvent to obtain a dispersion solution; An insulating filler is added to the dispersion to obtain a mixed solution; The mixed solution is coated and dried to obtain a rubber composite layer; Metal material is uniformly deposited on both sides of the rubber composite layer to form a metal sputtering layer on both sides of the rubber composite layer, thereby obtaining a plastic current collector.

7. The method for preparing the plastic current collector according to claim 6, characterized in that, The solid content of the mixed solution is 40-60%.

8. The method for preparing the plastic current collector according to claim 6 or 7, characterized in that, The solvent includes at least one of toluene, xylene, butyl butyrate, and n-alkanes.

9. The method for preparing the plastic current collector according to claim 6 or 7, characterized in that, The process of uniformly depositing metallic material on both sides of the rubber composite layer includes: The metal material is uniformly deposited on both sides of the rubber composite layer by any of the following methods: resistance evaporation, telemetry sputtering, or electron gun evaporation.

10. A positive electrode, characterized in that, Includes a plastic current collector and a positive electrode coating applied to at least one side of the plastic current collector; The plastic current collector is the plastic current collector as described in any one of claims 1-5, or a plastic current collector prepared by the preparation method of the plastic current collector as described in any one of claims 6-9.

11. A negative electrode, characterized in that, It includes a plastic current collector and a negative electrode coating applied to at least one side of the plastic current collector; The plastic current collector is the plastic current collector as described in any one of claims 1-5, or a plastic current collector prepared by the preparation method of the plastic current collector as described in any one of claims 6-9.

12. A solid-state battery, characterized in that, It includes the positive electrode as described in claim 10, the negative electrode as described in claim 11, and the electrolyte.

Images