Solid-state battery cell, battery device, electric device, and electrolyte sheet and preparation method therefor

Abstract

A solid-state battery cell, a battery device, an electric device, and an electrolyte sheet and a preparation method therefor. The solid-state battery cell comprises an electrolyte sheet and a negative electrode sheet. The electrolyte sheet comprises: a solid-state electrolyte base layer; and an electron blocking layer, which is arranged on the side of the solid-state electrolyte base layer close to the negative electrode sheet and comprises electron blocking particles, wherein each electron blocking particle comprises a core and a coating material provided on at least part of the surface of the core, the core and the solid-state electrolyte base layer separately comprise a solid-state electrolyte material, and the coating material comprises one or more of LiF and Li2S.

Description

Solid-state battery cells, battery devices, electrical devices, electrolyte sheets, and their preparation methods

[0001] Cross-references to related applications

[0002] This application claims priority to Chinese Patent Application No. 202411803851.X, filed on December 09, 2024, entitled "Solid-state battery cell, battery device, power device, electrolyte sheet and preparation method thereof", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates to a solid-state battery cell, a battery device, an electrical device, an electrolyte sheet, and a method for preparing the same. Background Technology

[0004] Solid-state battery cells use solid electrolytes instead of non-aqueous organic electrolytes. Since solid electrolytes cannot spontaneously permeate into the electrodes, they are typically used in combination with electrode active materials to improve the electrode's ion transport characteristics. Sulfide solid electrolyte materials are currently one of the ideal solid electrolyte materials; however, their poor oxidation and reduction resistance limits the range of solvents and binders that can be used, and also results in poor dispersibility of slurries containing them, making them prone to gelation and sedimentation problems. Summary of the Invention

[0005] This disclosure provides a solid-state battery cell, an electrolyte sheet, a method for preparing the same, a battery device, and an electrical device. The phenomenon of dendrites penetrating the electrolyte sheet in the solid-state battery cell is reduced, thereby improving the cycle capacity retention rate of the solid-state battery cell.

[0006] In a first aspect, this disclosure provides a solid-state battery cell, including an electrolyte sheet and a negative electrode sheet. The electrolyte sheet includes: a solid electrolyte base layer; an electron barrier layer disposed on the side of the solid electrolyte base layer near the negative electrode sheet; the electron barrier layer includes electron barrier particles, each electron barrier particle including a core and a coating material disposed on at least a portion of the surface of the core, wherein the core and the solid electrolyte base layer each include a solid electrolyte material, and the coating material includes one or more of LiF and Li2S.

[0007] According to an embodiment of this application, the electron blocking layer includes electron blocking particles, and the coating material in the electron blocking particles includes LiF and Li2S. This coating material has low electron transfer capability. The core is a solid electrolyte material, and the coating material is the aforementioned substance; therefore, the electron blocking particles have good ability to transport active ions. Thus, the electron blocking layer has low electron transfer capability but possesses a certain ability to transport active ions. The electron blocking layer can suppress active ions (LiF, Li2S ... + Or Na +The formation of metallic elements in the solid electrolyte substrate inhibits dendrite growth and also inhibits the formation of dendrites in the electron barrier layer, thus inhibiting dendrite growth at the electrolyte, such as lithium dendrites. Therefore, the solid-state battery cell of this application can reduce the phenomenon of dendrites penetrating the electrolyte sheet, reduce the probability of short circuits, and improve the reliability and cycle capacity retention of the solid-state battery cell.

[0008] Furthermore, this coating material possesses excellent water and chemical stability, and its surface adsorption energy is also low. When coated on the core surface, it can significantly suppress the degradation of solid electrolyte materials, such as those found in PS4, during electrochemical cycling of solid-state battery cells. 3- The decomposition of H2S reduces the amount of gases such as H2S, which helps improve the stability of solid-state battery cells.

[0009] In some optional embodiments, the solid electrolyte material includes one or more of sulfide solid electrolyte materials, halide solid electrolyte materials, and oxide solid electrolyte materials.

[0010] In some alternative embodiments, the core and the solid electrolyte layer respectively comprise Li 10 GeP2S 12 Li6PS5Cl, Li7P3S 11 Li7La3Zr2O 12 One or more of the following: polyethylene oxide (PEO). Cores or solid electrolyte substrates composed of the above-mentioned materials exhibit excellent conduction properties for active ions, enabling the transport of active ions and improving the rate capability of solid-state battery cells.

[0011] In some alternative embodiments, the electronic conductivity of the electron barrier layer is 0.8 × 10⁻⁶. -10 S / cm to 2×10 -9 S / cm, selectable as 1×10 -10 S / cm up to 1.22×10 -9 S / cm. This indicates that the low conductivity of the electron barrier layer can suppress dendrite growth at the electrolyte, reduce the phenomenon of dendrites penetrating the electrolyte sheet, lower the probability of short circuits, and improve the reliability of solid-state battery cells.

[0012] In some optional embodiments, the electron barrier layer comprises, by weight percentage, 0.05% to 2.5% binder and 97.5% to 99.5% electron barrier particles. The electron barrier layer comprising the above-mentioned weight percentage components can reduce dendrite penetration of the electrolyte sheet, reduce the probability of short circuits, and improve the reliability and cycle capacity retention of solid-state battery cells.

[0013] In some optional embodiments, the thickness ratio of the solid electrolyte substrate to the electron barrier layer is 10:4 to 15:1. Since the active ion transport capacity of the electron barrier layer is less than that of the solid electrolyte substrate, and the solid electrolyte sheet and the electron barrier layer easily form complex ion pathways that affect ion transport performance, controlling the thickness ratio of the solid electrolyte substrate to the electron barrier layer within the above range reduces the impact of the barrier layer on the active ion transport of the solid-state battery cell, which is beneficial for balancing the rate performance of the solid-state battery cell.

[0014] In some optional embodiments, the thickness of the solid electrolyte substrate is 50 μm to 150 μm; optionally, it is 80 μm to 100 μm. A thickness within this range provides a larger buffer space, which helps maintain mechanical contact at the interface between the electrolyte sheet and the electrode, provides better mechanical strength, reduces the risk of lithium dendrite penetration, and improves reliability; it also provides a larger mechanical barrier, effectively suppressing lithium dendrite growth and enhancing reliability.

[0015] In some optional embodiments, the thickness of the electron blocking layer is 10 μm to 20 μm, optionally 12 μm to 18 μm. A thickness within this range can suppress active ions (Li...). + Or Na + Forming metallic elements in the solid electrolyte substrate can suppress dendrite growth, reduce dendrite penetration of the electrolyte sheet, decrease the probability of short circuits, and improve the reliability and cycle capacity retention of solid-state battery cells.

[0016] In some optional embodiments, the electron-blocking particles have a core-shell structure. The core-shell structure of the electron-blocking particles indicates that the coating material completely encapsulates the core, thus better suppressing active ions (Li). + Or Na + By forming metallic elements in the solid electrolyte substrate, dendrite growth is suppressed. Therefore, the solid-state battery cell of this application can reduce the phenomenon of dendrites penetrating the electrolyte sheet, reduce the probability of short circuits, and improve the reliability and cycle capacity retention of the solid-state battery cell.

[0017] In some alternative embodiments, the average volumetric particle size Dv of the electron-blocking particles 1 50 ranges from 0.55 μm to 1.28 μm, with an optional range of 0.8 μm to 1.1 μm. The average volumetric particle size Dv of the electron-blocking particles. 1 Within the aforementioned range, 50% is beneficial for the uniformity of the electron-blocking layer thickness and the overall blocking effect on electron transport, thus better suppressing active ions (Li). + Or Na +By forming metallic elements in the solid electrolyte substrate, dendrite growth is suppressed. Therefore, the solid-state battery cell of this application can reduce the phenomenon of dendrites penetrating the electrolyte sheet, reduce the probability of short circuits, and improve the reliability and cycle capacity retention of the solid-state battery cell.

[0018] In some alternative embodiments, the average volumetric particle size Dv of the nucleus 2 50 is 0.5 μm to 1.2 μm, optionally 0.7 μm to 1.0 μm. The average volumetric diameter of the nucleus, Dv. 2 Within the above range, 50 is conducive to forming electron-blocking particles with suitable particle size, which can take into account certain active ion transport performance, reduce the phenomenon of dendrite penetration into the electrolyte sheet, reduce the probability of short circuit, and improve the reliability and cycle capacity retention of solid-state battery cells.

[0019] In some optional embodiments, the average thickness of the coating material on the core surface is 50 nm to 80 nm, optionally 60 nm to 70 nm. An average thickness of the coating material on the core surface within this range is beneficial for blocking electrons and improving the transport capability of active ions. This allows solid-state battery cells to simultaneously reduce dendrite penetration through the electrolyte sheet and improve the electrochemical performance of the solid-state battery cells.

[0020] In some optional embodiments, the powder resistivity of the electron-blocking particles is 0.57 × 10⁻⁶. 3 Up to 0.8×10 3 Ωm; can be selected as 0.62×10 3 Up to 0.78×10 3 The resistivity of the electron blocking particles is within the above range (Ωm), indicating that the electron blocking particles have very low conductivity, close to that of insulating materials. This effectively reduces electron transport and decreases the phenomenon of dendrites penetrating the electrolyte sheet.

[0021] In some optional embodiments, the electron-blocking particles have a lithium-ion conductivity of 1.25 × 10⁻⁶ at 25°C. -3 S / cm up to 1.74×10 -3 S / cm, can be selected as 1.3×10 -3 S / cm up to 1.7×10 -3 S / cm. Therefore, it is beneficial to improve the transport rate of active ions in solid-state battery cells during charge-discharge cycles, ensuring the smooth transport of active ions and balancing the reliability and rate capability of solid-state battery cells.

[0022] Secondly, embodiments of this application provide a battery device including a plurality of solid-state battery cells as described in the first aspect. The battery device of this application embodiment at least has the beneficial effects of solid-state battery cells.

[0023] Thirdly, embodiments of this application provide an electrical device, including a solid-state battery cell (as described in the first aspect) or a battery device (as described in the second aspect). The electrical device of this application embodiment possesses at least the beneficial effects of a solid-state battery cell or a battery device.

[0024] Fourthly, embodiments of this application provide an electrolyte sheet for a solid-state battery cell. The electrolyte sheet includes: a solid electrolyte base layer; an electron barrier layer disposed on the side of the solid electrolyte base layer near the negative electrode; the electron barrier layer includes electron barrier particles, each electron barrier particle including a core and a coating material disposed on at least a portion of the surface of the core, wherein the core and the solid electrolyte base layer each include a solid electrolyte material, and the coating material includes one or more of LiF and Li2S.

[0025] According to an embodiment of this application, the electron blocking layer includes electron blocking particles, and the coating material in the electron blocking particles includes LiF and Li2S. This coating material has low electron transfer capability. The core is a solid electrolyte material, and the coating material is the aforementioned substance; therefore, the electron blocking particles have good ability to transport active ions. Thus, the electron blocking layer has low electron transfer capability but possesses a certain ability to transport active ions. The electron blocking layer can suppress active ions (LiF, Li2S ... + Or Na + The solid-state battery cell forms a metallic element in the solid electrolyte substrate, which inhibits dendrite growth. Therefore, the solid-state battery cell of this application can reduce the phenomenon of dendrites penetrating the electrolyte sheet, reduce the probability of short circuits, and improve the reliability and cycle capacity retention of the solid-state battery cell.

[0026] Furthermore, this coating material exhibits excellent water and chemical stability, and can significantly suppress the presence of substances like those found in PS4 solid-state electrolytes during electrochemical cycling of solid-state battery cells. 3- The decomposition of H2S reduces the amount of gases such as H2S, which helps improve the stability of solid-state battery cells.

[0027] Fifthly, embodiments of this application provide a method for preparing an electrolyte sheet for a solid-state battery cell, comprising: providing electron-blocking particles, the electron-blocking particles comprising a core and a coating material disposed on at least a portion of the surface of the core, wherein the core comprises a solid electrolyte material and the coating material comprises one or more of LiF and Li2S;

[0028] An electron barrier layer is formed on the surface of a solid electrolyte substrate by electrodeposition of a solution containing electron barrier particles, or by coating a solution containing electron barrier particles onto the surface of a solid electrolyte substrate to form an electron barrier layer, in order to prepare an electrolyte sheet. The solid electrolyte substrate includes a solid electrolyte material, and the electron barrier layer is used to be disposed on the side of the solid electrolyte substrate near the negative electrode sheet.

[0029] According to embodiments of this application, an electron-blocking layer is formed on the surface of a solid electrolyte substrate using electrodeposition or coating methods to prepare an electrolyte sheet. The electron-blocking layer includes electron-blocking particles, and the coating material in the electron-blocking particles includes LiF and Li₂S. This coating material has low electron transfer capability. The core is a solid electrolyte material, and the coating material is the aforementioned substances. Therefore, the electron-blocking particles have good ability to transport active ions. Thus, the electron-blocking layer has low electron transfer capability but a certain ability to transport active ions. The electron-blocking layer can suppress active ions (Li₂S, Li ... + Or Na + The formation of metallic elements in the solid electrolyte substrate improves the reliability and cycle capacity retention of solid-state battery cells.

[0030] In some optional embodiments, the mass ratio α of the solid electrolyte substrate and the electron barrier layer satisfies 5.3:1 ≤ a ≤ 7.85:1. A mass ratio α of α within this range is beneficial for the solid electrolyte substrate and the electron barrier layer to form complex ion pathways, reducing the impact on the active ion transport of the solid-state battery cell and helping to maintain the rate performance of the solid-state battery cell. Attached Figure Description

[0031] To more clearly illustrate the technical solutions of the embodiments of this disclosure, the accompanying drawings used in the embodiments of this disclosure will be briefly described below. Obviously, the drawings described below are merely some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on the drawings without any creative effort.

[0032] Figure 1 shows a schematic diagram of a solid-state battery cell provided in some embodiments of this disclosure.

[0033] Figure 2 shows a schematic diagram of an electrical device provided in some embodiments of this disclosure.

[0034] Figure 3 shows a schematic diagram of the structure of an electrolyte sheet provided in some embodiments of this disclosure.

[0035] Figure 4 shows a microscopic image of the electron-barrier particles provided in some embodiments of this disclosure.

[0036] The accompanying drawings are not necessarily drawn to scale. Detailed Implementation

[0037] The following detailed description, with appropriate reference to the accompanying drawings, provides specific embodiments of the solid-state battery cell, battery device, power-consuming device, electrolyte sheet, and preparation method thereof. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of practically identical structures may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand this disclosure and are not intended to limit the subject matter of the claims.

[0038] The "range" disclosed in this disclosure is defined by a lower limit and an upper limit, whereby a given range is defined by selecting a lower limit and an upper limit, which define the boundaries of the particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a specific parameter, it is expected that ranges of 60-110 and 80-120 are also expected. Furthermore, if minimum range values ​​1 and 2 are listed, and if maximum range values ​​3, 4, and 5 are listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this disclosure, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this article; "0-5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0039] Unless otherwise specified, all embodiments and optional embodiments of this disclosure may be combined with each other to form new technical solutions, and such technical solutions should be considered as included in the disclosure of this disclosure.

[0040] Unless otherwise specified, all technical features and optional technical features of this disclosure can be combined to form new technical solutions, and such technical solutions should be considered as included in the disclosure of this disclosure.

[0041] Unless otherwise specified, all steps of this disclosure may be performed sequentially or randomly, preferably sequentially. For example, if a method includes steps (a) and (b), it means that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, if it is mentioned that the method may also include step (c), it means that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0042] Unless otherwise specified, in this disclosure, the terms "first," "second," etc., are used to distinguish different objects, rather than to describe a specific order or primary / secondary relationship.

[0043] In this disclosure, the terms "multiple" or "a variety" refer to two or more kinds.

[0044] In the description of the embodiments of this disclosure, unless otherwise specified, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0045] Unless otherwise stated, the test temperature for all parameters mentioned in this disclosure is 25°C.

[0046] The solid-state battery cell mentioned in the embodiments of this disclosure can independently perform charge and discharge functions. After discharge, it can be reactivated by charging to allow for continued use. The solid-state battery cell can be cylindrical, cuboid, or other shapes, and the embodiments of this disclosure are not limited to this. Figure 1 shows a cuboid solid-state battery cell 5 as an example.

[0047] The battery apparatus mentioned in the embodiments of this disclosure may include one or more battery cell assemblies for providing voltage and capacity. The battery cell assembly may include multiple solid-state battery cells, which are connected in series, parallel, or mixed connections via busbars.

[0048] In some embodiments, the solid-state battery cell may further include an outer packaging for housing the negative electrode, electrolyte, and positive electrode. The outer packaging may be a rigid shell, such as a hard plastic shell, aluminum shell, or steel shell. The outer packaging may also be a flexible package, such as a pouch. The material of the flexible package may be plastic, such as one or more of aluminum-plastic film, polypropylene, polybutylene terephthalate (PBT), and polybutylene succinate (PBS).

[0049] In some embodiments, a battery cell assembly is typically formed by arranging multiple solid-state battery cells.

[0050] As an example, a battery cell assembly can be a battery module, which is formed by arranging and fixing multiple solid-state battery cells together to form an independent module. As another example, a battery module can be formed by bundling multiple solid-state battery cells together with cable ties.

[0051] In some embodiments, the battery device may be a battery pack, which includes a housing and one or more individual battery cells housed within the housing.

[0052] As an example, the battery cell assembly can be a battery module, which can be housed in a housing by fixing the battery module in the housing.

[0053] As an example, battery cell assemblies can also be housed in a housing by directly fixing multiple solid-state battery cells to the housing.

[0054] As an example, the enclosure may include a first enclosure and a second enclosure. The first enclosure and the second enclosure are fastened together to form a closed space inside the enclosure to house the individual battery cells. Here, "closed" refers to covering or closing, and can be either sealed or unsealed. The first enclosure may be a top cover or a bottom plate.

[0055] As an example, the enclosure may include a top cover, a frame, and a bottom plate. The top cover and bottom plate are connected to the frame, creating an enclosed space inside the enclosure to house the individual battery cells.

[0056] In some embodiments, the housing may be part of the vehicle's chassis structure. For example, a portion of the housing may be at least a part of the vehicle's floor, or a portion of the housing may be at least a part of the vehicle's crossbeams and longitudinal beams.

[0057] The technical solutions described in this disclosure are applicable to various electrical devices that use solid-state battery cells or battery devices, such as, but not limited to, mobile devices (e.g., mobile phones, tablets, laptops, etc.), electric vehicles (e.g., pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc. Solid-state battery cells and battery devices are used to store or provide electrical energy.

[0058] Figure 2 is a schematic diagram of an example electrical device. This electrical device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc.

[0059] The solid-state battery cells disclosed herein may include coin cells, molded cells, hard-case cells, pouch cells, etc.

[0060] This disclosure also provides a solid-state battery cell comprising a positive electrode, an electrolyte sheet, and a negative electrode. In some optional embodiments, the electrolyte sheet is located between the positive and negative electrode sheets.

[0061] Solid-state battery cells are mainly composed of a negative electrode, an electrolyte, and a positive electrode, pressed into a dense cell structure using a thermostatic pressing process. However, during use, the electrolyte, due to its inherent conductivity of electrons and ions, allows active ions to transfer from the positive electrode to the electrolyte. Because the electrolyte conducts electrons, these active ions can form metallic substances within the electrolyte. These metallic substances not only react with the electrolyte but also cause more cracks in the electrolyte sheet, damaging its structure and affecting the electrochemical performance and reliability of the solid-state battery cell.

[0062] Based on this, the present disclosure provides a solid-state battery cell in which an electron barrier layer is disposed on the side of the solid electrolyte substrate near the negative electrode. This layer can suppress dendrite growth at the electrolyte sheet, protect the solid electrolyte substrate, reduce the phenomenon of lithium dendrites penetrating the electrolyte sheet, reduce the probability of short circuits, and improve the reliability and electrochemical performance of the solid-state battery cell.

[0063] In some optional embodiments, the solid-state battery cell includes an electrolyte sheet and a negative electrode sheet; the solid electrolyte sheet includes: a solid electrolyte base layer; an electron barrier layer disposed on the side of the solid electrolyte base layer near the negative electrode sheet; the electron barrier layer includes electron barrier particles, the electron barrier particles including a core and a coating material disposed on at least a portion of the surface of the core, wherein the core and the solid electrolyte base layer each include a solid electrolyte material, and the coating material includes one or more of LiF and Li2S.

[0064] Solid electrolyte substrate can be understood as a layer structure formed by solid electrolyte, which has the ability to generate active ions and conduct electrons, and can play the role of solid electrolyte in traditional solid-state battery cells.

[0065] According to an embodiment of this application, the electron blocking layer includes electron blocking particles, and the coating material in the electron blocking particles includes LiF and Li2S. This coating material has low electron transfer capability. The core is a solid electrolyte material, and the coating material is the aforementioned substance; therefore, the electron blocking particles have good ability to transport active ions. Thus, the electron blocking layer has low electron transfer capability but possesses a certain ability to transport active ions. The electron blocking layer can suppress active ions (LiF, Li2S ... + Or Na + The formation of metallic elements in the solid electrolyte substrate inhibits dendrite growth and also inhibits the formation of dendrites in the electron barrier layer, thus inhibiting dendrite growth at the electrolyte, such as lithium dendrites. Therefore, the solid-state battery cell of this application can reduce the phenomenon of dendrites penetrating the electrolyte sheet, reduce the probability of short circuits, and improve the reliability and cycle capacity retention of the solid-state battery cell.

[0066] The electron barrier layer can protect the solid electrolyte substrate, reduce the direct contact between the metal elements deposited on the surface of the negative electrode and the electrolyte, thereby reducing damage to the solid electrolyte substrate and improving the electrochemical performance of the solid battery cell.

[0067] Furthermore, this coating material possesses excellent water and chemical stability, and its surface adsorption energy is also low. When coated on the core surface, it can significantly suppress the degradation of solid electrolyte materials, such as those found in PS4, during electrochemical cycling of solid-state battery cells. 3- The decomposition of H2S reduces the amount of gases such as H2S, which helps improve the stability of solid-state battery cells.

[0068] Generally, active ions form metallic elements on the surface of the negative electrode, such as lithium ions forming lithium or sodium ions forming sodium. In the embodiments of this application, active ions can form metallic elements between the electron blocking layer and the negative electrode.

[0069] In some optional embodiments, the solid electrolyte material includes one or more of sulfide solid electrolyte materials, halide solid electrolyte materials, and oxide solid electrolyte materials.

[0070] In some alternative embodiments, the core and the solid electrolyte layer respectively comprise Li 10 GeP2S 12 Li6PS5Cl, Li7P3S 11 Li7La3Zr2O 12One or more of the following: polyethylene oxide (PEO). Cores or solid electrolyte substrates composed of the above-mentioned materials exhibit excellent conduction properties for active ions, enabling the transport of active ions and improving the rate capability of solid-state battery cells.

[0071] During the charging and discharging process, solid-state battery cells undergo Li insertion / extraction and consumption, resulting in varying Li molar content at different discharge states. This disclosure relates to Cs... X M y [Mo a (CN) b (NO) c In the list of nH2O materials, the molar content of Li refers to the initial state of the material, i.e., the state before feeding. Cs X M y [Mo a (CN) b (NO) c When nH₂O is used in solid-state battery cells, the molar content of Li changes after charge-discharge cycles. In the examples of lithium-rich manganese-based materials in this disclosure, the molar content of O is only a theoretical value; lattice oxygen release causes changes in the molar content of O, and the actual molar content of O will also fluctuate. The molar content of the active ion Na ions is consistent with that of Li.

[0072] In some alternative embodiments, the electronic conductivity of the electron barrier layer is 0.8 × 10⁻⁶. -10 S / cm to 2×10 -9 S / cm, selectable as 1×10 -10 S / cm up to 1.22×10 -9 S / cm. For example, the electronic conductivity of the electron barrier layer can be 1.0 × 10⁻⁶. -10 S / cm, 1.5×10 -10 S / cm, 2.5×10 -10 S / cm, 5×10 -10 S / cm, 6×10 -10 S / cm, 7×10 -10 S / cm, 8×10 -10 S / cm, 9×10 -10 S / cm, 9.5×10 -10 S / cm, 1.0×10 -9 S / cm, 1.5×10 -9 S / cm, etc. This indicates that the low conductivity of the electron barrier layer can suppress dendrite growth at the electrolyte sheet, reduce the phenomenon of dendrite penetration into the electrolyte sheet, reduce the probability of short circuits, and improve the reliability of solid-state battery cells.

[0073] The electronic conductivity can be measured as follows: A sample of the electron barrier layer is taken and placed in a pressing mold under a pressure of 2000 kg to form a small disc of a certain thickness and area. The thickness (l) and diameter (D) of the disc are measured. The impedance R is measured by connecting the two ends of the disc to the positive and negative terminals of a CT-4008Q-5V100MA-164 Xinwei battery testing system. Resistance (R) = conductivity (σ) × thickness (l) / cross-sectional area (A). Therefore, electronic conductivity (σ) = resistance (R) × A (disc area) / thickness (l). Multiple samples can be taken from different locations in the electron barrier layer to obtain the average value.

[0074] In some optional embodiments, the electron barrier layer comprises, by weight percentage, 0.05% to 2.5% binder and 97.5% to 99.5% electron barrier particles. Optionally, the electron barrier layer comprises, by weight percentage, 0.1% to 1.5% binder and 98% to 99% electron barrier particles; more preferably, the electron barrier layer comprises, by weight percentage, 0.5% to 1.0% binder and 99% to 99.5% electron barrier particles. The electron barrier layer comprising the above-mentioned weight percentage components can reduce dendrite penetration of the electrolyte sheet, reduce the probability of short circuits, and improve the reliability and cycle capacity retention of solid-state battery cells.

[0075] In some optional embodiments, the thickness ratio of the solid electrolyte substrate to the electron barrier layer is 10:4 to 15:1. Since the active ion transport capacity of the electron barrier layer is less than that of the solid electrolyte substrate, and the solid electrolyte sheet and the electron barrier layer easily form complex ion pathways that affect ion transport performance, controlling the thickness ratio of the solid electrolyte substrate to the electron barrier layer within the above range reduces the impact of the barrier layer on the active ion transport of the solid-state battery cell, which is beneficial for balancing the rate performance of the solid-state battery cell.

[0076] In solid-state battery cells, the boundary between the solid electrolyte substrate and the electron barrier layer is difficult to distinguish. It can be measured by the thickness ratio during fabrication, or by cutting the solid-state battery cell into a smooth cross-section as shown in Figure 3, observing the cross-section using an optical microscope or scanning electron microscope (SEM), and then measuring the thickness of the electrolyte substrate or electron barrier layer using microscopy software. Figure 3 shows that the solid-state battery cell 5 may include a positive electrode 30, an electrolyte sheet 20, and a negative electrode 10. The electrolyte sheet 20 includes a solid electrolyte substrate 22 and an electron barrier layer 21.

[0077] In some optional embodiments, the thickness of the solid electrolyte substrate is 50 μm to 150 μm; optionally, it is 80 μm to 100 μm.

[0078] Optionally, the thickness of the solid electrolyte substrate can be any value or a range of combinations thereof from 50μm, 60μm, 70μm, 80μm, 90μm, 100μm, 110μm, 120μm, 130μm, 140μm, and 150μm.

[0079] When the thickness of the solid electrolyte substrate is within the above range, it can provide a larger buffer space, which helps maintain the mechanical contact between the electrolyte sheet and the electrode, provides better mechanical strength, reduces the risk of lithium dendrite penetration, and improves reliability; it also provides a larger mechanical barrier, effectively suppressing lithium dendrite growth and improving reliability.

[0080] In some optional embodiments, the thickness of the electron blocking layer is 10 μm to 20 μm, optionally 12 μm to 18 μm.

[0081] Optionally, the thickness of the electron blocking layer can be any value or a range of combinations thereof from 10μm, 11μm, 12μm, 13μm, 14μm, 15μm, 16μm, 17μm, 18μm, 19μm, and 20μm.

[0082] When the thickness of the electron-blocking layer is within the above range, it can suppress active ions (Li). + Or Na + Forming a metallic element within the solid electrolyte substrate inhibits dendrite growth, reducing dendrite penetration into the electrolyte sheet, lowering the probability of short circuits, and improving the reliability and cycle capacity retention of solid-state battery cells. An electron barrier layer within the aforementioned thickness range protects the solid electrolyte substrate, thereby reducing surface damage to the electrolyte sheet and improving the electrochemical performance of the solid-state battery cell.

[0083] In some optional embodiments, the electron-blocking particles have a core-shell structure. The core-shell structure of the electron-blocking particles indicates that the coating material completely encapsulates the core, thus better suppressing active ions (Li). + Or Na + By forming metallic elements in the solid electrolyte substrate, dendrite growth is suppressed. Therefore, the solid-state battery cell of this application can reduce the phenomenon of dendrites penetrating the electrolyte sheet, reduce the probability of short circuits, and improve the reliability and cycle capacity retention of the solid-state battery cell.

[0084] In addition, the coating material has good water stability and chemical stability, which is beneficial to improving the stability of solid-state battery cells.

[0085] Figure 4 shows microscopic images of electron-blocking particles provided in some embodiments of this disclosure. As can be seen from Figures (a) and (b), the coating material is located on the core surface, indicating that the electron-blocking particles have a structure consisting of a core and a coating material.

[0086] In some alternative embodiments, the average volumetric particle size Dv of the electron-blocking particles 1 50 ranges from 0.55 μm to 1.28 μm, with an optional range of 0.8 μm to 1.1 μm.

[0087] Optionally, the average volumetric particle size Dv of the electron-blocking particles 1 50 can be any value or a range of combinations thereof from 0.55μm, 0.60μm, 0.65μm, 0.70μm, 0.75μm, 0.80μm, 0.85μm, 0.90μm, 0.95μm, 1.00μm, 1.05μm, 1.10μm, 1.15μm, 1.20μm, and 1.28μm.

[0088] The average volumetric particle size Dv of electron-blocking particles 1 Within the aforementioned range, 50% is beneficial for the uniformity of the electron-blocking layer thickness and the overall blocking effect on electron transport, thus better suppressing active ions (Li). + Or Na + By forming metallic elements in the solid electrolyte substrate, dendrite growth is suppressed. Therefore, the solid-state battery cell of this application can reduce the phenomenon of dendrites penetrating the electrolyte sheet, reduce the probability of short circuits, and improve the reliability and cycle capacity retention of the solid-state battery cell.

[0089] In some alternative embodiments, the average volumetric particle size Dv of the nucleus 2 50 is 0.5μm to 1.2μm, and can be selected from 0.7μm to 1.0μm.

[0090] Optionally, the average volumetric diameter Dv of the nucleus 2 50 can be any value or a range thereof from 0.50μm, 0.55μm, 0.60μm, 0.65μm, 0.70μm, 0.75μm, 0.80μm, 0.85μm, 0.90μm, 0.95μm, 1.00μm, 1.05μm, 1.10μm, 1.15μm, and 1.20μm. The average volumetric particle size Dv of the nucleus. 2 Within the above range, 50 is conducive to forming electron-blocking particles with suitable particle size, which can take into account certain active ion transport performance, reduce the phenomenon of dendrite penetration into the electrolyte sheet, reduce the probability of short circuit, and improve the reliability and cycle capacity retention of solid-state battery cells.

[0091] The average volumetric particle size Dv of electron-blocking particles 1 50. The average volumetric diameter of the nucleus, Dv 2The value of 50 has a well-known meaning in the art and can be tested using methods known in the art. For example, it can be determined using a laser particle size analyzer (such as a Malvern Mastersize 3000). The test can be performed in accordance with GB / T 19077.1-2016. Here, Dv50 represents the particle size corresponding to a cumulative volume distribution percentage of 50% for the positive electrode active material.

[0092] The average volumetric particle size Dv of electron-blocking particles 1 50. The average volumetric diameter of the nucleus, Dv 2 50 can also be understood as the average particle size of the electron-blocking particles observed in the electrolyte sheet. The average particle size can also be tested as follows: Using a scanning electron microscope (SEM) according to JY / T010-1996, obtain an SEM image of the electron-blocking layer. Randomly select a test sample with dimensions of 50mm x 100mm on the electron-blocking layer. Randomly select multiple test areas (e.g., 5) within the test sample, and read the particle size of each particle in each test area at a certain magnification (e.g., 500x or higher). Count the number and particle size values ​​of particles in each test area, and take the arithmetic mean of the particle sizes in all test areas as the average particle size. To ensure the accuracy of the test results, multiple test samples (e.g., 10) can be used for the above test, and the average value of each test sample can be taken as the final test result. The testing instrument can be a ZEISS Sigma 300. It should be noted that when the particles are irregularly shaped, the distance between the two farthest points on the particle is taken as the particle size of that electron-blocking particle; multiple measurements can be taken and the average value taken. When detecting the average volumetric particle size of the nucleus, the coating material of the electron-blocking particles can be removed for measurement, or the particle size of the nucleus can be measured. Multiple test samples (e.g., 10) can be taken for the above test, and the average value of the nuclei of each test sample is taken as the final test result.

[0093] In some optional embodiments, the average thickness of the coating material on the core surface is 50 nm to 80 nm, optionally 60 nm to 70 nm. Optionally, the thickness of the solid electrolyte substrate can be any value or a range of combinations thereof from 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 110 nm, 120 nm, 130 nm, 140 nm, and 150 nm.

[0094] The average thickness of the coating material on the core surface is within the above range, which is beneficial for blocking electrons and improving the transport capacity of active ions. This allows solid-state battery cells to reduce dendrite penetration of the electrolyte sheet and improve the electrochemical performance of the solid-state battery cells.

[0095] The average thickness of the coating material on the nucleus surface can be determined by cutting the granular electron-blocking particles, observing the boundary between the nucleus and the coating material under a microscope from the cut surface, and taking the average value after multiple measurements of the coating material thickness on the nucleus surface.

[0096] In some optional embodiments, the powder resistivity of the electron-blocking particles is 0.57 × 10⁻⁶. 3 Up to 0.8×10 3 Ωm; can be selected as 0.62×10 3 Up to 0.78×10 3 Ωm. For example, the powder resistivity of the electron-blocking particles can be 0.58 × 10⁻⁶. 3 Ω·m, 0.60×10 3 Ω·m, 0.65×10 3 Ω·m, 0.70×103Ω·m, 0.75×10 3 Ω·m, 0.80×10 3 The resistivity of the electron blocking particles is within the above range, indicating that the electron conductivity of the particles is very low, close to that of insulating materials. This effectively reduces electron transport and decreases the phenomenon of dendrite penetration through the electrolyte sheet.

[0097] The resistivity of electron-blocking particles is a well-known concept in the art and can be tested using instruments and methods known in the field. For example, a resistivity meter (such as the ST2722 powder resistivity meter from Suzhou Jingge Electronics Co., Ltd.) can be used. During testing, a 1g powder sample is placed between the electrodes of the resistivity meter, and a constant pressure (e.g., 4 MPa) is applied using an electronic pressure gauge for 15-25 seconds to obtain a sheet-like sample. The powder resistivity δ of the material is calculated using the formula δ = (S × R) / h, in Ω·cm. h is the height of the sheet-like sample in cm; R is the resistance in Ω; and S is the area of ​​the sheet-like sample in cm². 2 .

[0098] In some optional embodiments, the electron-blocking particles have a lithium-ion conductivity of 1.25 × 10⁻⁶ at 25°C. -3 S / cm up to 1.74×10 -3 S / cm, can be selected as 1.3×10 -3 S / cm up to 1.7×10 -3 S / cm. Therefore, it is beneficial to improve the transport rate of active ions in solid-state battery cells during charge-discharge cycles, ensuring the smooth transport of active ions and balancing the reliability and rate capability of solid-state battery cells.

[0099] Method for detecting the ionic conductivity of electron-blocking particles at 25℃: At 25℃, 100mg of electron-blocking particles were sampled and placed in a tableting mold, then pressed into an electron-blocking layer film under a pressure of 4000Kg. The thickness was measured and recorded as L. A sheet was then pressed into a plate under a pressure of 2000Kg on each side. Next, 60mg of indium powder was placed on each side of the sleeve, and a sheet was pressed into a plate under a pressure of 2000Kg on each side. Finally, lithium-plated copper sheets were placed on each side of the sleeve to assemble a symmetrical battery. A pressure of 4000Kg was applied to the symmetrical battery and held for 5 minutes. The AC impedance value R of the electron-blocking layer was obtained using electrochemical impedance spectroscopy (EIS) on an electrochemical workstation. The test temperature was 25℃, and the test frequency range was 10 Hz. 6 -10 -2 Hz, bias voltage is 10mV.

[0100] The ionic conductivity of electron-blocking particles is calculated using the following formula: σ = L / (R*S). L is the thickness of the electron-blocking layer, R is the AC impedance value in the AC impedance spectrum, and S is the area of ​​the electron-blocking layer.

[0101] In some alternative embodiments, the solid electrolyte substrate includes a solid electrolyte material, a solvent, and a binder soluble in the solvent.

[0102] In some optional embodiments, the solvent is a nonpolar solvent, a weakly polar solvent, or a mixture of both. In some optional embodiments, the solvent includes toluene, xylene, trimethylbenzene, chlorobenzene, o-dichlorobenzene, anisole, n-hexane, n-pentane, isopentane, n-heptane, n-octane, isooctane, n-decane, trichlorotrifluoroethane, dichloromethane, trichloromethane, 2-methylpentane, 2,2-dimethylpentane, 3-methylpentane, 2,3-dimethylpentane, 2-methylhexane, 2,2-dimethylhexane, 3-methylhexane, 2,3-dimethylhexane, 3-ethylhexane, cyclohexane, cycloheptane, etc. One or more of the following: methylcyclohexane, tert-butylcyclohexane, tetrahydrofuran, cyclopentene, cyclohexene, 1-methylcyclohexene, 4-methylcyclohexene, 1-ethylcyclohexene, 1,4-dimethylcyclohexene, 2,4-dimethyl-3-pentanone, cyclohexanone, methylformamide, 1-hexene, 2-hexene, 1-heptene, 2-heptene, 1-octene, 2-octene, vinyl dichloride, petroleum ether, trifluoroacetic acid, butyl chloride, trichloroethylene, carbon tetrachloride, propyl ether, diethyl ether, butyl acetate, and ethyl acetate.

[0103] The adhesive may include, but is not limited to, one or more of the following: polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), ethylene-tetrafluoroethylene-propylene terpolymer, ethylene-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, styrene-butadiene rubber (SBR), water-soluble unsaturated resin SR-1B, methyl vinyl silicone rubber, nitrile rubber (NBR), hydrogenated nitrile rubber (HNBR), thermoplastic styrene-butadiene rubber (SBS), isoprene rubber, cis-butadiene rubber (BR), ethyl cellulose, fluororubber, and acrylate rubber.

[0104] In some embodiments, the total mass content of the binder in the electrolyte sheet may be 0.5%-10% based on the total mass of the electrolyte sheet (100%).

[0105] In some embodiments, the electrolyte sheet may or may not include a binder, depending on the manufacturing process of the solid-state battery cell.

[0106] In some alternative embodiments, the adhesive includes one or more of polyacrylate adhesives and nonpolar polyolefin adhesives.

[0107] In some optional embodiments, the nonpolar polyolefin binder includes a homopolymer nonpolar polyolefin binder selected from one of the following monomers, and one or more copolymer nonpolar polyolefin binders selected from two or more of the following monomers: ethylene, propylene, butene, isobutene, pentene, hexene, heptyl, octene, butadiene, pentadiene, isoprene, hexadiene, octadiene, 2,3-dimethyl-1,3-butadiene, 3-methyl-1,3-pentadiene, and 4-methyl-1,3-pentadiene.

[0108] In some alternative embodiments, the nonpolar polyolefin binder includes one or more of polyethylene, polypropylene, polybutene, polyisobutylene, polybutadiene, polyisoprene, ethylene-propylene copolymer, ethylene-butene copolymer, ethylene-octene copolymer, ethylene-propylene-butene copolymer, ethylene-propylene-octene copolymer, isoprene-butadiene copolymer, ethylene-isoprene copolymer, and ethylene-hexadiene copolymer.

[0109] [Preparation method of electrolyte tablets]

[0110] Solid electrolyte substrates can be prepared using either dry or wet processes.

[0111] This application provides a method for preparing an electrolyte sheet for Anta solid-state batteries, comprising:

[0112] Step 100: Provide electron blocking particles, the electron blocking particles including a core and a coating material disposed on at least a portion of the surface of the core, wherein the core includes a solid electrolyte material and the coating material includes one or more of LiF and Li2S;

[0113] Step 200: An electron barrier layer is formed on the surface of a solid electrolyte substrate by electrodeposition of a solution containing electron barrier particles, or an electron barrier layer is formed by coating a solution containing electron barrier particles onto the surface of a solid electrolyte substrate, so as to obtain an electrolyte sheet. The solid electrolyte substrate includes a solid electrolyte material, and the electron barrier layer is used to be disposed on the side of the solid electrolyte substrate near the negative electrode sheet.

[0114] According to embodiments of this application, an electron-blocking layer is formed on the surface of a solid electrolyte substrate using electrodeposition or coating methods to prepare an electrolyte sheet. The electron-blocking layer includes electron-blocking particles, and the coating material in the electron-blocking particles includes LiF and Li₂S. This coating material has low electron transfer capability. The core is a solid electrolyte material, and the coating material is the aforementioned substances. Therefore, the electron-blocking particles have good ability to transport active ions. Thus, the electron-blocking layer has low electron transfer capability but a certain ability to transport active ions. The electron-blocking layer can suppress active ions (Li₂S, Li ... + Or Na + The solid-state battery cell forms a metallic element in the solid electrolyte substrate, which inhibits dendrite growth. Therefore, the solid-state battery cell of this application can reduce the phenomenon of dendrites penetrating the electrolyte sheet, reduce the probability of short circuits, and improve the reliability and cycle capacity retention of the solid-state battery cell.

[0115] For example, when preparing an electron barrier layer using electrodeposition, the main component of the electron barrier layer is electron barrier particles. In some optional embodiments, the electron barrier layer may be partially coated with solid electrolyte material. When preparing an electron barrier layer using electrodeposition, a certain amount of binder can be added to improve the bonding strength between the electron barrier particles and between the electron barrier particles and the solid electrolyte substrate.

[0116] In some alternative embodiments, electron-blocking particles are dissolved in a solvent to prepare a solution containing the electron-blocking particles. The noble metal (e.g., Pt, Au, Ag) electrodes in the electrodeposition tank are cleaned to ensure their surfaces are clean and free of impurities. The electrodes are connected to a power source, with the solution containing the electron-blocking particles serving as the cathode and the other electrode as the anode. Under controlled conditions of 25°C, a current of 0.5 mA / cm² is applied, and electrodeposition is performed for a period of time to obtain the electron-blocking layer.

[0117] For example, when preparing an electron blocking layer using a coating method, a binder or other substances can be added to the solution containing the electron blocking particles to achieve the purpose of preparing the electron blocking layer. The blocking layer particles are dissolved in a solvent to form a solution with a viscosity ranging from 14000 Pa·s to 18000 Pa·s, preferably 16000 Pa·s. The coating temperature can be between 110 and 130°C for uniform coating. The solvent can be an organic alkane, such as cyclohexane or n-hexane.

[0118] In some alternative embodiments, the method for preparing electron-blocking particles includes:

[0119] Mix solid electrolyte materials with soluble fluoride salts or soluble sulfur salts.

[0120] The reaction occurs at a temperature of 180-220°C to obtain electron-blocking particles. The electron-blocking particles include a core and a coating material on at least a portion of the surface of the core. The core includes a solid electrolyte material, and the coating material includes one or more of LiF and Li2S.

[0121] In some alternative embodiments, the method for preparing electron-blocking particles includes:

[0122] Li 10 GeP2S 12 The mixture was prepared by mixing NH4F as a precursor at a mass ratio of (105:1) to (110.5:1), followed by an in-situ gas-solid phase reaction at a high temperature of 180-220℃ to obtain electron-blocking particles.

[0123] It is understandable that NH4F decomposes into NH3 and HF gases, when Li 10 GeP2S 12 Upon contact with HF gas, the following reaction occurs: 2⁴HF + Li⁻ 10 GeP2S 12 =10LiF+GeF4↑+2PF5↑+12H2S↑, Li 10 GeP2S 12 The surface undergoes a fluorination reaction with HF, thus allowing a layer of LiF to be coated onto its surface, resulting in LiF-coated Li. 10 GeP2S 12 The material can be LiF coated Li 10 GeP2S 12 The core-shell structure effectively reduces the electronic conductivity of the electrolyte and inhibits lithium dendrites from damaging the electrolyte sheet.

[0124] In some optional embodiments, the mass ratio α of the solid electrolyte substrate and the electron barrier layer satisfies 5.3:1 ≤ a ≤ 7.85:1. Optionally, the mass ratio α can be 5.30:1, 5.35:1, 5.40:1, 5.45:1, 5.50:1, 5.55:1, 5.60:1, 5.65:1, 5.70:1, 5.75:1, 5.80:1, 5.85:1, 5.90:1, 5.95:1, 6.00:1, 6.05:1, 6.10:1, 6.20:1, 6.30:1, 6. Get the range formed by any value from .40:1, 6.50:1, 6.60:1, 6.65:1, 6.70:1, 6.80:1, 6.90:1, 7.00:1, 7.10:1, 7.20:1, 7.30:1, 7.40:1, 7.45:1, 7.50:1, 7.60:1, 7.70:1, 7.75:1, 7.80:1, 7.85:1.

[0125] When the mass ratio α of the solid electrolyte substrate and the electron barrier layer is within the above range, it is beneficial for the solid electrolyte substrate and the electron barrier layer to form complex ion pathways, reducing the impact on the active ion transport of solid battery cells and helping to balance the rate performance of solid battery cells.

[0126] [Positive electrode tablets]

[0127] In some embodiments, the positive electrode sheet may include a positive current collector and a positive electrode film layer located on at least one surface of the positive current collector. The positive electrode film layer includes a positive electrode active material, a positive electrode conductive agent, an optional solid electrolyte material, and a binder. The types of positive electrode active material, positive electrode conductive agent, solid electrolyte material, and binder can be referred to the context and will not be described in detail here; alternatively, the positive electrode film layer may be obtained by drying the positive electrode slurry provided in this disclosure.

[0128] The positive electrode current collector has two surfaces opposite each other in its thickness direction, and the positive electrode film layer is disposed on either or both of the two opposite surfaces of the positive electrode current collector.

[0129] In some embodiments, the positive current collector may be a metal foil or a composite current collector. Examples of metal foils include aluminum foil, carbon-coated aluminum foil, and stainless steel foil. The composite current collector may include a polymer substrate and a metal layer formed on at least one surface of the polymer substrate. Examples of metal materials include, but are not limited to, one or more of aluminum, aluminum alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys. Examples of polymer substrates include, but are not limited to, one or more of polypropylene, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), and polyethylene.

[0130] In some optional embodiments, the surface of the positive electrode includes a solid electrolyte material. Including a solid electrolyte material on the surface of the positive electrode can reduce interfacial cracking or debonding of the solid electrolyte or the negative electrode surface, improve the contact between the solid electrolyte and the positive electrode, reduce interfacial impedance, and improve the rate capability of the solid-state battery.

[0131] In some embodiments, the positive electrode film may further include a solid electrolyte material.

[0132] In some embodiments, the positive electrode sheet includes a positive current collector, a positive active material, and an optional solid electrolyte material located on at least one surface of the positive current collector.

[0133] In some embodiments, the positive current collector can be a metal foil or a composite current collector. The metal foil can be a pure metal, an alloy, or a surface-treated metal, such as, but not limited to, stainless steel foil, carbon-coated aluminum foil, aluminum foil, nickel foil, and titanium foil. The composite current collector can include a polymer substrate and a metal material layer formed on at least one surface of the polymer substrate. As an example, the metal material can be, but is not limited to, one or more of aluminum, aluminum alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys. As an example, the polymer substrate can be, but is not limited to, one or more of polypropylene, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), and polyethylene.

[0134] In some embodiments, the positive electrode may not require an additional positive current collector; for example, the stainless steel sheet of a molded battery can be used directly as the positive current collector.

[0135] In some embodiments, the positive electrode sheet may further include a positive electrode conductive agent, which may include, but is not limited to, one or more of conductive graphite (such as KS-6, SFG-6), superconducting carbon, acetylene black, carbon black (such as SP), Ketjen black (such as ECP), carbon dots, carbon nanotubes, graphene, carbon nanofibers, and vapor-grown carbon fibers (VGCF).

[0136] In some embodiments, the positive electrode sheet may or may not include a positive electrode binder, depending on the composition of the positive electrode and the manufacturing process of the solid-state battery cell. Optionally, the positive electrode binder may include, but is not limited to, one or more of the following: polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), ethylene-tetrafluoroethylene-propylene terpolymer, ethylene-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, fluorinated acrylate resin, water-soluble unsaturated resin SR-1B, methyl vinyl silicone rubber, nitrile rubber (NBR), hydrogenated nitrile rubber (HNBR), styrene-butadiene rubber (SBR), thermoplastic styrene-butadiene rubber (SBS), isoprene rubber, butadiene rubber (BR), ethyl cellulose, polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA), carboxymethyl chitosan (CMCS), fluororubber, and acrylate rubber.

[0137] Positive electrode sheets can be prepared using either dry or wet processes.

[0138] [Negative electrode plate]

[0139] Negative electrode sheets can be prepared using either dry or wet processes.

[0140] In some embodiments, the negative electrode may include one or more of lithium, lithium alloy, natural graphite, artificial graphite, mesophase micro carbon spheres, soft carbon, hard carbon, silicon-based materials, tin-based materials, lithium titanate, and metal oxides.

[0141] Optionally, the mass fraction of lithium in the lithium alloy can be above 90%.

[0142] Optionally, other elements in the lithium alloy may include, but are not limited to, one or more of In, Mg, Al, Zn, Sn, Ag, Au, Ga, Pt, and Fe.

[0143] Alternatively, the lithium alloy may include, but is not limited to, InLi alloy, Li-Mg alloy, Li-Al alloy, Li-Zn alloy, Li-Fe alloy, etc.

[0144] Optionally, the silicon-based material may include, but is not limited to, one or more of elemental silicon, silicon oxide, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys.

[0145] Optionally, the tin-based material may include, but is not limited to, one or more of elemental tin, tin oxide, and tin alloy materials.

[0146] Optionally, the metal oxide may be one or more of TiO2, MoO2, In2O3, Al2O3, Cu2O, VO2, Ga2O3, Sb2O5, and Bi2O5.

[0147] In some embodiments, the negative electrode can be a metal sheet, such as a lithium sheet or a lithium alloy sheet.

[0148] In some embodiments, the negative electrode sheet may include a negative current collector and a lithium-based metal layer located on at least one surface of the negative current collector. The negative current collector has two surfaces opposite each other in its thickness direction, and the lithium-based metal layer is disposed on either or both of the two opposite surfaces of the negative current collector.

[0149] In some embodiments, the lithium-based metal layer may include lithium or a lithium alloy.

[0150] In some embodiments, the negative electrode sheet may include a negative electrode current collector and a negative electrode film layer located on at least one surface of the negative electrode current collector, the negative electrode film layer including a negative electrode active material. The negative electrode current collector has two surfaces opposite each other in its thickness direction, and the negative electrode film layer is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0151] In some embodiments, the negative electrode active material may include, but is not limited to, one or more of natural graphite, artificial graphite, mesophase micro carbon spheres, soft carbon, hard carbon, silicon-based materials, tin-based materials, lithium titanate, and metal oxides.

[0152] In some embodiments, the negative electrode film layer further includes a negative electrode binder, which may include, but is not limited to, one or more of the following: styrene-butadiene rubber (SBR), water-soluble unsaturated resin SR-1B, polyacrylic acid, polymethacrylic acid, sodium polyacrylate, polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), carboxymethyl chitosan (CMCS), methyl vinyl silicone rubber, nitrile rubber (NBR), hydrogenated nitrile rubber (HNBR), thermoplastic styrene-butadiene rubber (SBS), isoprene rubber, cis-butadiene rubber (BR), ethyl cellulose, fluororubber, and acrylate rubber.

[0153] In some embodiments, the negative electrode film layer may or may not include a negative electrode conductive agent.

[0154] Optionally, the negative electrode conductive agent may be one or more of the following, including but not limited to conductive graphite (such as KS-6, SFG-6), superconducting carbon, acetylene black, carbon black (such as SP), Ketjen black (such as ECP), carbon dots, carbon nanotubes, graphene, carbon nanofibers, and vapor-grown carbon fibers (VGCF).

[0155] In some optional embodiments, the surface of the negative electrode includes a solid electrolyte material. Including a solid electrolyte material on the surface of the negative electrode can reduce interfacial cracking or debonding of the solid electrolyte or the negative electrode surface, improve the contact between the solid electrolyte and the negative electrode, reduce interfacial impedance, and improve the rate capability of the solid-state battery.

[0156] In some embodiments, the negative electrode film layer may further include a solid electrolyte material. Optionally, the solid electrolyte material may include, but is not limited to, one or more of sulfide solid electrolyte materials, halide solid electrolyte materials, and oxide solid electrolyte materials.

[0157] The types of sulfide solid electrolyte materials can be found in the section on sulfide solid electrolyte materials for positive electrodes above, and will not be repeated here.

[0158] Optionally, the halide solid electrolyte material may include one or more of Li3YCl6, Li3YBr6, Li3ErCl6, Li3InCl6, and Li3InBr6.

[0159] Optionally, the oxide solid electrolyte material may include one or more of the following: perovskite structure oxide solid electrolyte material, garnet structure oxide solid electrolyte material, NASICON structure oxide solid electrolyte material, and LISICON structure oxide solid electrolyte material.

[0160] In some embodiments, the negative electrode current collector can be a metal foil, a three-dimensional porous current collector, or a composite current collector. As a metal foil, pure metals, alloys, or surface-treated metals can be used, such as, but not limited to, stainless steel foil, copper foil, copper alloy foil, nickel foil, nickel alloy foil, aluminum foil, and aluminum alloy foil. Examples of three-dimensional porous current collectors include copper mesh, nickel mesh, aluminum mesh, foamed copper, foamed nickel, and foamed aluminum. The composite current collector can include a polymer material substrate and a metal material layer formed on at least one surface of the polymer material substrate. As an example, the metal material can include, but is not limited to, one or more of copper, copper alloys, aluminum, aluminum alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys. As an example, the polymer material substrate can include, but is not limited to, one or more of polypropylene, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene, and polyethylene.

[0161] Example

[0162] The following embodiments describe the disclosure of this disclosure in more detail. These embodiments are merely illustrative, as various modifications and variations will be apparent to those skilled in the art within the scope of this disclosure. Unless otherwise stated, all parts, percentages, and ratios reported in the following embodiments are based on mass, and all reagents used in the embodiments are commercially available or synthesized by conventional methods and can be used directly without further processing, and the instruments used in the embodiments are commercially available.

[0163] Electrolyte tablets D1#

[0164] Li 10 GeP2S 12 LiF was mixed with NH4F as a precursor at a mass ratio of (110:1), and then subjected to an in-situ gas-solid phase reaction at 200°C to prepare electron-blocking particles, namely LiF-coated Li. 10 GeP2S 12 The core-shell structure. The average volumetric diameter Dv of electron-blocking particles. 1 50 is 0.9μm.

[0165] An electron-blocking layer was formed on the surface of a solid electrolyte substrate using electrodeposition. The solution contained 75.6% electron-blocking particles by mass, and the solvent was n-hexane with a mass fraction of 24.4%. Specific steps included: placing the electron-blocking particle solution (approximately 50 ml) in an electrodeposition tank; cleaning the Ag electrode to ensure its surface was clean and free of impurities; immersing both electrodes in a homogeneous n-hexane solution; turning on the stirrer and setting its speed to 500 rpm; maintaining the electrolytic cell temperature at 25°C; and using a PINE WaveDriver 100 workstation connected to the two electrodes via a power supply, applying an A / cm² voltage. 2 A current was applied at 20-second intervals to ensure uniform deposition of electron-blocking particles in the solvent onto the solid electrolyte substrate. The entire process took 5 hours to complete, yielding an electrolyte sheet containing an electron-blocking layer. The electron-blocking layer comprised 100% electron-blocking particles by mass to form the electrolyte sheet. The solid electrolyte substrate included Li... 10 GeP2S 12 The electrolyte sheet is 70 μm thick, the electron blocking layer is 10 μm thick, and the solid electrolyte base layer is 60 μm thick. The electrolyte is 98:2 by mass with styrene-butadiene rubber (SBR) as the binder.

[0166] Electrolyte tablets D2#

[0167] An electrolyte sheet is prepared by coating a solid electrolyte substrate with a solution containing electron-blocking particles, wherein the electron-blocking particles have a mass fraction of 70.2%, and the solvent is n-hexane with a mass fraction of 26.8%. The solution also contains 3% styrene-butadiene rubber (SBR). The electron-blocking layer is formed by coating the solution with styrene-butadiene rubber (SBR) to form an electron-blocking layer. The mass ratio of electron-blocking particles to SBR in the electron-blocking layer is 70.2:3.

[0168] Electrolyte tablets D3# to D5#

[0169] In this embodiment, the thickness ratio of the solid electrolyte base layer and the electron blocking layer in the electrolyte sheet is different, as shown in Table 1.

[0170] Electrolyte tablets D6# to D8#

[0171] In this embodiment, the raw materials for the electrolyte sheets are different. The electron blocking layers of the electrolyte sheets D6# to D9# sequentially include Li2S coated with Li 10 GeP2S 12 The core-shell structure of LiF coated with Li6PS5Cl, and the core-shell structure of Li2S coated with Li6PS5Cl.

[0172] Electrolyte sheet performance testing

[0173] 1) Electron conductivity testing of the electron barrier layer: A sample of the electron barrier layer is taken and placed in a pressing mold under a pressure of 2000 kg to form a small disc of a certain thickness and area. The thickness (l) and diameter (D) of the disc are measured. The impedance R is measured by connecting the two ends of the disc to the positive and negative terminals of a CT-4008Q-5V100MA-164 Xinwei battery testing system. Resistance (R) = conductivity (σ) × thickness (l) / cross-sectional area (A), therefore, electron conductivity (σ) = resistance (R) × A (disc area) / thickness (l). Multiple samples can be taken from different locations of the electron barrier layer to obtain the average value.

[0174] 2) Ionic conductivity detection of electron-blocking particles: At 25°C, 100 mg of the electron-blocking particles prepared in the example were sampled and placed in a tableting mold. A pressure of 4000 kg was applied to press them into a film of the electron-blocking layer, and the thickness was measured and recorded as L. A pressure of 2000 kg was applied to each side to press them into sheets. Then, 60 mg of indium powder was placed on each side of the sleeve, and a pressure of 2000 kg was applied to each side to press them into sheets. Lithium-plated copper sheets were then placed on each side of the sleeve to assemble a symmetrical battery. A pressure of 4000 kg was applied to the symmetrical battery and held for 5 min. The AC impedance value R of the electron-blocking layer was obtained using electrochemical impedance spectroscopy (EIS) on an electrochemical workstation. The test temperature was 25°C, and the test frequency range was 10 Hz. 6 -10 -2Hz, bias voltage is 10mV.

[0175] The ionic conductivity of electron-blocking particles is calculated using the following formula: σ = L / (R*S). L is the thickness of the electron-blocking layer, R is the AC impedance value in the AC impedance spectrum, and S is the area of ​​the electron-blocking layer.

[0176] Table 1

[0177] The test results above show that the electron barrier layer in the electrolyte sheet disclosed herein has suitable ionic conductivity and electronic conductivity.

[0178] Example 1: Preparation of Solid-State Battery Cells

[0179] Preparation of positive electrode

[0180] The above-prepared positive electrode active material (Li) 1.2 Ni 0.13 Co 0.13 Mn 0.54 O2 powder and InCl3 powder in a 1:1 mass ratio), sulfide solid electrolyte material Li 10 GeP2S 12 The positive electrode conductive agent, vapor-grown carbon fiber (VGCF), and the positive electrode binder, polytetrafluoroethylene (PTFE), were mixed uniformly in a double planetary mixer at a solid content mass ratio of 70:26:2.5:1.5. The uniformly mixed material was then heated and pressurized in an internal mixer to form a granular material, which was then hot-rolled at 80°C to form a self-supporting electrode sheet. Finally, the electrode sheet was hot-rolled and combined with the positive electrode current collector aluminum foil to obtain the positive electrode sheet. The sulfide solid electrolyte material Li... 10 GeP2S 12 The average particle size is 700 nm.

[0181] Preparation of negative electrode sheet: The negative electrode active material silicon-carbon composite material and the negative electrode binder styrene-butadiene rubber are weighed and mixed at a solid mass ratio of 92.8:7.2 and added to the solvent N-methylpyrrolidone to make a negative electrode slurry. Then the negative electrode slurry is coated on both sides of copper foil and dried to obtain the negative electrode sheet.

[0182] Electrolyte sheet: Electrolyte sheet D1# is used as the electrolyte sheet in this embodiment.

[0183] Assembly: The positive electrode sheet, electrolyte sheet, and negative electrode sheet are stacked in sequence. After hot pressing at 500MPa for 5 minutes, they are placed in the outer packaging aluminum-plastic film for encapsulation to obtain solid-state battery cell D1#.

[0184] Examples 2 to 8

[0185] The difference between this embodiment and Embodiment 1 is that solid-state battery cells are prepared using electrolyte sheets D2# to D8# respectively.

[0186] Comparative Example 1

[0187] The difference between Comparative Example 1 and Example 1 is that the solid electrolyte base layer in electrolyte sheet D1# is used as the electrolyte sheet, and the total thickness of the electrolyte sheet in this comparative example is 70 μm.

[0188] Performance testing

[0189] (1) First coulombic efficiency test of solid-state battery cell

[0190] The test temperature was 25℃, and the solid-state battery cells were tested under a pressure of 15MPa.

[0191] The solid-state battery cells were charged at a constant current rate of 0.1C to a voltage of 4.3V (vs. Li). + / Li), the charging specific capacity at this time is recorded as the first charging specific capacity; then let it stand for 5 minutes, and then discharge at a constant current rate of 0.1C until the voltage is 2V (vs. Li). + / Li), the discharge specific capacity of this time is recorded as the first-cycle discharge specific capacity.

[0192] The initial coulombic efficiency (%) of a solid-state battery cell = first discharge specific capacity / first charge specific capacity × 100%.

[0193] (2) Cyclic performance test

[0194] At 25°C, the solid-state battery cell was first charged to 4.3V (vs. Li) at a current density of 0.1C. + / Li), let stand for 10 minutes, then discharge at a current density of 0.1C to 2.0V (vs. Li + / Li), cycle charge and discharge 3 times; then charge the solid-state battery cell to 4.3V at a current density of 0.33C (vs. Li). + / Li), let stand for 10 minutes, then discharge to 2.0V at a current density of 0.33C (vs. Li). + / Li), the discharge specific capacity at this time is recorded as C1. The solid-state battery cell is cycled for 200 times at a current density of 0.33C, and the discharge capacity at this time is recorded as C2.

[0195] Solid-state battery cell capacity retention rate after 200 cycles = C2 / C1 × 100%.

[0196] (3) Short circuit probability: 200 samples were set for each group of solid-state battery cells in the examples and comparative examples. After 200 cycles, the cells were disassembled, and the number of cells n in which lithium dendrites pierced the electrolyte sheet was recorded. This can be understood as the presence of dendrites on the positive electrode side by the naked eye or microscope indicating that lithium dendrites have pierced the electrolyte sheet. The short circuit probability was calculated using the formula % = n / 200 × 100%.

[0197] Table 2

[0198] As can be seen from the above test results, the electrolyte sheet disclosed herein has the characteristics of high ionic conductivity and low electronic conductivity, which can ensure the transport of active ions while effectively suppressing the growth of dendrites in the electrolyte, improving the short circuit probability of solid-state battery cells, and also improving the cycle capacity retention rate and initial coulombic efficiency of solid-state battery cells.

[0199] It should be noted that this disclosure is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same essential structure and achieving the same effect as the technical concept within the scope of this disclosure are included in the technical scope of this disclosure. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, are also included in the scope of this disclosure without departing from the spirit of this disclosure.

Claims

1. A solid-state battery cell, comprising an electrolyte sheet and a negative electrode sheet, wherein the electrolyte sheet comprises: Solid electrolyte base layer; An electron blocking layer is disposed on the side of the solid electrolyte substrate near the negative electrode sheet; the electron blocking layer includes electron blocking particles, each electron blocking particle including a core and a coating material disposed on at least a portion of the surface of the core, wherein the core and the solid electrolyte substrate each include a solid electrolyte material, and the coating material includes one or more of LiF and Li2S.

2. The solid-state battery cell according to claim 1, wherein, The solid electrolyte material includes one or more of the following: sulfide solid electrolyte material, halide solid electrolyte material, and oxide solid electrolyte material.

3. The solid-state battery cell according to claim 1 or 2, wherein, The core and the solid electrolyte substrate respectively include Li 10 GeP2S 12 Li6PS5Cl, Li 10 GeP2S 12 Li6PS5Cl, Li7P3S 11 Li7La3Zr2O 12 One or more of polyethylene oxide.

4. The solid-state battery cell according to any one of claims 1 to 3, wherein, The electronic conductivity of the electron barrier layer is 0.8 × 10⁻⁶. -10 S / cm to 2×10 -9 S / cm.

5. The solid-state battery cell according to any one of claims 1 to 4, wherein, The electronic conductivity of the electron barrier layer is 1×10⁻⁶. -10 S / cm up to 1.22×10 -9 S / cm.

6. The solid-state battery cell according to any one of claims 1 to 5, wherein, The electron blocking layer comprises, by weight percentage, 0.05% to 2.5% binder and 97.5% to 99.5% electron blocking particles.

7. The solid-state battery cell according to any one of claims 1 to 6, wherein, The electron blocking layer satisfies one or more of the following conditions: (1) The thickness ratio of the solid electrolyte base layer to the electron barrier layer is 10:4 to 15:1; (2) The thickness of the solid electrolyte substrate is 50 μm to 150 μm; (3) The thickness of the electron blocking layer is 10 μm to 20 μm.

8. The solid-state battery cell according to any one of claims 1 to 7, wherein, The electron-blocking particles have a core-shell structure.

9. The solid-state battery cell according to any one of claims 1 to 8, wherein, The electron-blocking particles satisfy one or more of the following conditions: (1) The average volumetric particle size Dv of the electron-blocking particles 1 50 ranges from 0.55 μm to 1.28 μm; (2) The average volumetric particle size Dv of the nucleus 2 50 ranges from 0.5 μm to 1.2 μm; (3) The average thickness of the coating material on the core surface is 50 nm to 80 nm; (4) The resistivity of the electron-blocking particles is 0.57 × 10⁻⁶. 3 Up to 0.8×10 3 Ωm; (5) The electron-blocking particles have an ionic conductivity of 1.25 × 10⁻⁶ at 25 °C. -3 S / cm up to 1.74×10 -3 S / cm.

10. The solid-state battery cell according to any one of claims 1 to 9, wherein, The electron-blocking particles satisfy one or more of the following conditions: (1) The average volumetric particle size Dv of the electron-blocking particles 1 50 ranges from 0.8 μm to 11 μm; (2) The average volumetric particle size Dv of the nucleus 2 50 ranges from 0.7 μm to 1.0 μm; (3) The average thickness of the coating material on the core surface is 60 nm to 70 nm; (4) The resistivity of the electron-blocking particles is 0.62 × 10⁻⁶. 3 Up to 0.78×10 3 Ωm; (5) The electron-blocking particles have an ionic conductivity of 1.3 × 10⁻⁶ at 25 °C. -3 S / cm up to 1.7×10 -3 S / cm.

11. A battery device, wherein, It includes a plurality of solid-state battery cells as described in any one of claims 1 to 10.

12. An electrical appliance, wherein, Includes the solid-state battery cell according to any one of claims 1 to 10 or the battery device according to claim 11.

13. An electrolyte sheet for a solid-state battery cell, wherein, The electrolyte sheet includes: Solid electrolyte base layer; An electron blocking layer is provided on the side of the solid electrolyte substrate near the negative electrode plate; the electron blocking layer includes electron blocking particles, each electron blocking particle including a core and a coating material disposed on at least a portion of the surface of the core, wherein the core and the solid electrolyte substrate each include a solid electrolyte material, and the coating material includes one or more of LiF and Li2S.

14. A method for preparing an electrolyte sheet for a solid-state battery cell, wherein, include: An electron-blocking particle is provided, the electron-blocking particle comprising a core and a coating material disposed on at least a portion of the surface of the core, wherein the core comprises a solid electrolyte material and the coating material comprises one or more of LiF and Li2S; The electrolyte sheet is prepared by forming an electron barrier layer on the surface of a solid electrolyte substrate using an electrodeposition method with a solution containing electron barrier particles, or by coating a solution containing electron barrier particles onto the surface of a solid electrolyte substrate to form an electron barrier layer. The solid electrolyte substrate comprises a solid electrolyte material, and the electron barrier layer is used to be disposed on the side of the solid electrolyte substrate near the negative electrode sheet.

15. The preparation method according to claim 14, wherein, The mass ratio a of the solid electrolyte substrate and the electron barrier layer satisfies 5.3:1≤a≤7.85:1.

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