Solid-state battery cell, positive electrode sheet, battery device, energy storage device, and electric device

Abstract

The present application relates to the technical field of batteries, and in particular relates to a solid-state battery cell, a positive electrode sheet, a battery device, an energy storage device, and an electric device. The positive electrode sheet in the solid-state battery cell comprises a positive electrode current collector and a positive electrode active layer disposed on at least one side of the positive electrode current collector, wherein the positive electrode active layer comprises a positive electrode active material, a solid electrolyte, and an interfacial wetting agent, with the interfacial wetting agent comprising an ionic liquid and a diluent. The present application can ameliorate the problem of solid-solid contact between the positive electrode active material and the solid electrolyte in the positive electrode sheet, and can improve the ionic conductivity of the positive electrode sheet.

Description

Solid-state battery cells, positive electrode plates, battery devices, energy storage devices, and electrical devices.

[0001] This application claims priority to Chinese Patent Application No. 202411918196.2, filed on December 24, 2024, entitled "Solid-state battery cell, positive electrode sheet, battery device, energy storage device, and power consumption device", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of battery technology, and in particular to solid-state battery cells, positive electrode sheets, battery devices, energy storage devices, and electrical devices. Background Technology

[0003] Solid-state batteries typically consist of a positive electrode active material and a solid electrolyte. The solid electrolyte primarily serves to provide ion transport channels and promote ion transport. However, in practice, positive electrode sheets often exhibit low ionic conductivity, making it difficult to meet requirements. Summary of the Invention

[0004] This application is made in view of the above-mentioned technical problems, and its purpose is to solve the problem of low ionic conductivity of the positive electrode in solid-state batteries.

[0005] To achieve the above objectives, this application provides a solid-state battery cell, a positive electrode, a battery device, an energy storage device, and an electrical device.

[0006] The first aspect of this application provides a solid-state battery cell, including a positive electrode sheet, the positive electrode sheet including a positive current collector and a positive active layer disposed on at least one side of the positive current collector, the positive active layer including a positive active material, a solid electrolyte and an interface wetting agent, the interface wetting agent including an ionic liquid and a diluent.

[0007] In this embodiment, a diluent and an ionic liquid are used together as the interface wetting agent for the positive electrode sheet. The diluent can dilute the ionic liquid, reduce its viscosity, and improve its fluidity, allowing the ionic liquid to effectively fill the gaps between the particles of the positive electrode sheet, thus improving the solid-solid contact between the positive electrode active material and the solid electrolyte. In this way, ions inside the positive electrode sheet can be transported between the positive electrode active material particles and the solid electrolyte particles through the ionic liquid in the particle gaps, thereby effectively improving the ion transport performance of the positive electrode sheet and giving it high ionic conductivity.

[0008] A positive electrode with high ionic conductivity is beneficial for reducing battery resistance and fully utilizing the capacity of the positive electrode. Therefore, batteries containing this positive electrode exhibit high first-efficiency and improved cycle performance.

[0009] In some embodiments, the diluent includes one or more of the following: sulfide compounds, saturated ester compounds, polyether polyol compounds, and sulfoxide compounds.

[0010] Thioether compounds include one or more of dimethyl sulfide (DMS), dimethyl disulfide, diphenyl sulfide, and diethyl sulfide.

[0011] Saturated ester compounds include one or more of methyl formate, ethyl formate, propyl formate, butyl formate, methyl acetate, ethyl acetate, propyl acetate, isoamyl acetate, and ethyl hexanoate.

[0012] Polyether polyols include one or more of polypropylene oxide diol, polytetrahydrofuran diol, and tetrahydrofuran-propylene oxide copolydiol.

[0013] Sulfoxide compounds include one or more of thionyl chloride and dimethyl sulfoxide.

[0014] These diluents can effectively dilute ionic liquids, reduce their viscosity, and improve their fluidity, allowing them to fill the gaps between particles in the positive electrode, thus improving the ion transport performance of the positive electrode.

[0015] In some embodiments, the anion contained in the ionic liquid includes bis(fluorosulfonyl)imide anion (FSI). - ), bis(trifluoromethanesulfonyl)imide anion (TFSI) - ), trifluoromethanesulfonic acid anion (OTf) - One or more of the following.

[0016] The cations contained in ionic liquids include one or more of the following: pyrrolidine cations, imidazole cations, piperidine cations, pyridine cations, and thiophene cations.

[0017] These ionic liquids exhibit excellent stability and ionic conductivity, are highly compatible with diluents, and do not react with common solid electrolytes.

[0018] In some embodiments, the mass ratio of ionic liquid to diluent is 1:(0.05-5), optionally 1:(0.2-3), and even more optionally 1:(0.2-1).

[0019] By mixing ionic liquids and diluents in an appropriate ratio, the diluent can effectively dilute the ionic liquid, allowing it to fully fill the gaps between the particles in the positive electrode and improve its ionic conductivity. Furthermore, when the mass ratio of ionic liquid to diluent is 1:(0.2–3), or optionally 1:(0.2–1), in addition to achieving high ionic conductivity in the positive electrode, it can also effectively improve battery performance, such as increasing initial efficiency and improving cycle performance, without causing damage during cycling.

[0020] In some embodiments, the interface wetting agent also includes an electrolyte salt. The electrolyte salt, together with the ionic liquid and diluent, can form an interface wetting agent similar to an electrolyte, and together with the ionic liquid and diluent, fill the interparticle voids of the positive electrode sheet, which is beneficial for promoting ion transport.

[0021] In some embodiments, the mass ratio of ionic liquid to electrolyte salt is 1:(0.5-2), optionally 1:(0.5-1). At this electrolyte salt mass ratio, ion transport can be effectively promoted, thereby increasing the ionic conductivity of the positive electrode.

[0022] In some embodiments, the interface wetting agent has a mass content of 1% to 10% in the positive electrode active layer, optionally 3% to 6%. At this content, the interface wetting agent can fully fill the gaps between the particles of the positive electrode, reduce voids, and promote ion transport.

[0023] A second aspect of this application provides a positive electrode sheet, including a positive current collector and a positive active layer disposed on at least one side of the positive current collector. The positive active layer includes a positive active material, a solid electrolyte, and an interface wetting agent, wherein the interface wetting agent includes an ionic liquid and a diluent.

[0024] In this embodiment, a diluent and an ionic liquid are used together as the interface wetting agent for the positive electrode sheet. The diluent can dilute the ionic liquid, reduce its viscosity, and improve its fluidity, allowing the ionic liquid to effectively fill the gaps between the particles of the positive electrode sheet. In this way, ions inside the positive electrode sheet can be transported between the positive active material particles and the solid electrolyte particles through the ionic liquid in the particle gaps, thereby effectively improving the ionic conductivity of the positive electrode sheet.

[0025] This application also provides some related devices, including battery devices, energy storage devices, and power consumption devices.

[0026] The battery device includes multiple solid-state battery cells.

[0027] The solid-state battery cell of this application embodiment has good cycle performance. Therefore, applying the solid-state battery cell to a battery device can help improve the cycle performance of the battery device and extend the service life of the battery device.

[0028] Energy storage devices include multiple solid-state battery cells or multiple battery devices, which are used to store or provide electrical energy.

[0029] The aforementioned solid-state battery cells and battery devices with good cycle performance are used to store or provide electrical energy for energy storage devices, which can extend the service life of energy storage devices.

[0030] Electrical devices include multiple solid-state battery cells or multiple battery devices, which are used to store or provide electrical energy.

[0031] The aforementioned solid-state battery cells and battery devices with good cycle performance can be used as power sources for electrical devices or as energy storage units for electrical devices, thereby increasing the capacity of electrical devices and extending their service life. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 is a schematic diagram of the microstructure of the positive electrode sheet in an embodiment of this application;

[0034] Figure 2 is a schematic diagram of a battery cell according to an embodiment of this application;

[0035] Figure 3 is an exploded view of a battery cell according to an embodiment of this application shown in Figure 2.

[0036] Reference numerals: 01-Housing, 02-Cover plate, 03-Electrode assembly. Detailed Implementation

[0037] The embodiments of this application are hereby disclosed in detail with appropriate reference to the accompanying drawings. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of actually identical structures may be omitted. This is to avoid making the following description unnecessarily lengthy 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 application and are not intended to limit the subject matter of the claims.

[0038] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a 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 understood that ranges of 60–110 and 80–120 are also expected. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 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 application, unless otherwise stated, the numerical range "a–b" 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 application can be combined to form new technical solutions.

[0040] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0041] Unless otherwise specified, all steps in this application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates 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, the terms "comprising" and "including" as used in this application can be open-ended or closed-ended. For example, "comprising" and "including" can mean that other components not listed may also be included, or that only the listed components may be included.

[0043] Unless otherwise specified, the term "or" is inclusive in this application. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, the condition "A or B" is satisfied by any of the following conditions: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0044] The positive electrode of a solid-state battery typically consists of a positive electrode active material and a solid electrolyte. The active material and the electrolyte are in contact in a solid-solid manner; more specifically, the contact between the active material particles and the electrolyte particles is usually point-to-point, resulting in insufficient and uneven contact. The solid electrolyte primarily provides ion transport channels in the positive electrode, promoting ion transport. If the contact between the active material and the electrolyte is poor, ions cannot transport smoothly between them, leading to poor ion transport performance, low ionic conductivity, and inability to fully utilize the battery's capacity. This also results in insufficient cycle stability.

[0045] To address this issue, some researchers have attempted to add ionic liquids containing dissolved electrolyte salts as a liquid coating layer for the positive electrode active material during the abrasive grinding process, i.e., the preparation of the positive electrode slurry; or to directly add ionic liquids to solid electrolytes (such as oxide solid electrolytes) and use a solid-liquid hybrid electrolyte to prepare the positive electrode.

[0046] However, due to the viscosity of ionic liquids, they are not easy to flow. Therefore, when a liquid coating layer containing electrolyte salt and ionic liquid is prepared on the surface of the positive electrode active material, or when ionic liquid is added to the solid electrolyte, the ionic liquid can only come into local contact with the positive electrode active material and the solid electrolyte. Moreover, the ionic conductivity of the liquid coating layer composed of electrolyte salt and ionic liquid is low. Therefore, the added ionic liquid is difficult to effectively transport ions between the positive electrode active material and the solid electrolyte, and its effect on improving the ion transport performance of the positive electrode is limited. The ionic conductivity of the positive electrode is still low.

[0047] The insufficient ion transport performance of the positive electrode is mainly due to the gaps between the positive electrode active material particles and the solid electrolyte particles in the positive electrode sheet. These gaps make it difficult for ions to transport, and the solid-solid contact impedance between the particles is relatively large. Moreover, during charge-discharge cycles, the volume of the positive electrode active material changes, which exacerbates the solid-solid contact problem, that is, it increases and enlarges these gaps, further reducing the ion conductivity of the positive electrode sheet.

[0048] Based on this, in this embodiment of the application, an interface wetting agent is added to the positive electrode of the solid-state battery cell. The interface wetting agent includes an ionic liquid and a diluent. The diluent can reduce the viscosity of the ionic liquid and improve its fluidity, allowing the ionic liquid to fully enter the interior of the positive electrode, fill the gaps between particles, and simultaneously contact the positive electrode active material and the solid electrolyte, providing a channel for ion transport between the positive electrode active material and the solid electrolyte, thereby improving the ionic conductivity of the positive electrode.

[0049] The solid-state battery cell of this application embodiment includes a positive electrode, a negative electrode, and a solid electrolyte. The solid electrolyte is disposed between the positive and negative electrode and is in contact with both electrodes. During battery charging and discharging, active ions move back and forth between the positive and negative electrode, inserting and extracting. The solid electrolyte acts as a transporter of ions between the positive and negative electrode.

[0050] [Positive electrode plate]

[0051] The positive electrode sheet of this application embodiment includes a positive current collector and a positive active layer disposed on at least one side of the positive current collector. The positive active layer includes a positive active material, a solid electrolyte, and an interface wetting agent, which includes an ionic liquid and a diluent.

[0052] Ionic liquids are room-temperature (20℃~25℃) organic molten salts composed of organic cations and organic or inorganic anions, typically exhibiting high ionic conductivity. Diluents are low-viscosity reagents (or solvents) that have a diluting effect.

[0053] In the embodiments of this application, the interface wetting agent includes ionic liquids and diluents, more specifically including the case where the ionic liquid is dispersed or dissolved in the diluent.

[0054] The positive electrode active layer comprises a positive electrode active material, a solid electrolyte, and an interface wetting agent. Typically, the positive electrode active material, solid electrolyte, and interface wetting agent are mixed together, optionally in a homogeneous mixture. Since the diluent can dilute the ionic liquid, reducing its viscosity and increasing its flowability, the ionic liquid in the interface wetting agent typically fills the gaps between the particles of the positive electrode sheet, including the gaps between positive electrode active material particles and solid electrolyte particles, the gaps between positive electrode active material particles, and the gaps between solid electrolyte particles.

[0055] The substances in the positive electrode active layer can be analyzed and identified using infrared spectroscopy, nuclear magnetic resonance, and other techniques.

[0056] In this embodiment, a diluent and an ionic liquid are used together as the interface wetting agent for the positive electrode sheet. The diluent can dilute the ionic liquid, reduce its viscosity, and improve its fluidity, allowing the ionic liquid to effectively fill the gaps between the particles of the positive electrode sheet. This improves the solid-solid contact between the positive electrode active material and the solid electrolyte, as shown in Figure 1 (the positive electrode material in Figure 1 includes the positive electrode active material and the solid electrolyte). In this way, ions inside the positive electrode sheet can be rapidly transported between the positive electrode active material particles and the solid electrolyte particles through the ionic liquid in the particle gaps, thereby effectively improving the ion transport performance of the positive electrode sheet and giving it high ionic conductivity.

[0057] In some embodiments, the diluent includes one or more of the following: sulfide compounds, saturated ester compounds, polyether polyol compounds, and sulfoxide compounds.

[0058] Thioether compounds are organic compounds containing thioether bonds, including one or more of dimethyl sulfide (DMS), dimethyl disulfide, diphenyl sulfide, and diethyl sulfide.

[0059] Saturated ester compounds can be represented by the general formula R1-COO-R2, where R1 and R2 each independently include an alkyl group, for example, each independently includes a C1-C18 alkyl group, such as methyl, ethyl, propyl, butyl, pentyl, or hexyl. Exemplary saturated ester compounds include one or more of methyl formate, ethyl formate, propyl formate, butyl formate, methyl acetate, ethyl acetate, propyl acetate, isoamyl acetate, and ethyl hexanoate.

[0060] Polyether polyols are oligomers whose main chain contains ether bonds and whose end groups or side groups contain more than two hydroxyl groups. Exemplary polyether polyols include one or more of polypropylene oxide glycol, polytetrahydrofuran glycol, and tetrahydrofuran-propylene oxide copolyol.

[0061] Sulfoxide compounds can be represented by the general formula R3-SO-R4, where R3 and R4 represent various carbon-containing organic groups. Exemplary sulfoxide compounds include one or more of thionyl chloride and dimethyl sulfoxide.

[0062] Diluents are low-viscosity reagents (or solvents) that have a diluting effect. They should be chemically stable and not react with ionic liquids, positive electrode active materials, solid electrolytes, or positive electrode current collectors. Diluents such as thioether compounds can effectively dilute ionic liquids, reducing their viscosity and increasing their flowability. This allows the ionic liquid to effectively fill the gaps between particles in the positive electrode, thus improving the ionic conductivity of the positive electrode.

[0063] In some embodiments, the anion contained in the ionic liquid includes bis(fluorosulfonyl)imide anion (FSI). - ), bis(trifluoromethanesulfonyl)imide anion (TFSI) - ), trifluoromethanesulfonic acid anion (OTf) - One or more of the following.

[0064] The cations contained in ionic liquids include one or more of the following: pyrrolidine cations, imidazole cations, piperidine cations, pyridine cations, and thiophene cations.

[0065] Among them, pyrrolidine cations include one or more of N-alkyl-N-methylpyrrolidine cations and N-alkyl-N-propylpyrrolidine cations.

[0066] Imidazole cations include one or more of 1-alkylimidazolium cations, 1-alkyl-3-methylimidazolium cations, and 1-alkyl-2,3-dimethylimidazolium cations.

[0067] Piperidine cations include one or more of N-alkyl-N-methylpiperidine cations and N-alkyl-N-propylpiperidine cations.

[0068] Pyridine cations include N-alkylpyridine cations.

[0069] Thiophene cations include thiophene methyl ammonium chloride cations.

[0070] The alkyl group may include one or more of the following: methyl, ethyl, propyl, butyl, pentyl, hexyl, octyl, decyl, dodecyl, tetradecyl, hexadecyl, and octadecyl.

[0071] Exemplary cations include 1-ethyl-3-methylimidazolium cation (EMIM). + ), 1-Butyl-3-methylimidazolium cation (BMIM) + ), N-methyl-N-propylpyrrolidine cation (Pyr13) + ), N-methyl-N-propylpiperidine cation (PP13) + One or more of the following.

[0072] Exemplary ionic liquids include one or more of 1-methyl-1-propylpyrrolidine bis(trifluoromethanesulfonyl)imide (Pyr13TFSI), N-methyl-N-propylpiperidine bis(trifluoromethanesulfonyl)imide (PP13TFSI), 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (EMIMTFSI), 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (BMIMTFSI), and 1-ethyl-3-methylimidazolium trifluoromethanesulfonate ([EMIM]OTf).

[0073] These ionic liquids exhibit excellent stability and ionic conductivity, and are highly compatible with diluents, without reacting with common solid electrolytes. Typically, in cases where the solid electrolyte includes a sulfide solid electrolyte, the ionic liquids in the embodiments of this application are halogen-free, thus maintaining stability between the ionic liquid and the solid electrolyte and preventing reaction.

[0074] In some embodiments, the mass ratio of the ionic liquid to the diluent is 1:(0.05 to 5), optionally 1:(0.2 to 3), and even more optionally 1:(0.2 to 1). For example, this mass ratio can be any one of the following values ​​or a range between any two: 1:0.05, 1:0.1, 1:0.2, 1:0.25, 1:0.3, 1:0.4, 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1, 1:1.5, 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5, 1:5.

[0075] The mass ratio of ionic liquid to diluent can be obtained by thermogravimetric analysis; or mass spectrometry can be used to obtain mass information of fragments related to ionic liquid and diluent, thereby calculating the relevant mass ratio.

[0076] By mixing ionic liquids and diluents in an appropriate ratio, the diluent can effectively dilute the ionic liquid, allowing it to fully fill the gaps between the particles in the positive electrode and improving its ion transport performance. Furthermore, when the mass ratio of ionic liquid to diluent is 1:(0.2–3), or optionally 1:(0.2–1), in addition to achieving high ionic conductivity in the positive electrode, it can also effectively improve battery performance, such as increasing initial efficiency and cycle performance, without causing damage during cycling.

[0077] In some embodiments, the interface wetting agent further includes an electrolyte salt. Optionally, the electrolyte salt includes the same anion as the ionic liquid, thereby improving the compatibility of the electrolyte salt with the ionic liquid. The cation in the electrolyte salt can be adaptively selected according to the battery type; for example, for lithium-ion batteries, lithium ions can be selected as the cation of the electrolyte salt, and for sodium-ion batteries, sodium ions can be selected as the cation of the electrolyte salt. Exemplary electrolyte salts include one or more of lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), and lithium trifluoromethanesulfonate (LiOTf).

[0078] Understandably, the electrolyte salt may also include one or more of lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium perchlorate (LiClO4), lithium hexafluoroarsenate (LiAsF6), lithium difluorooxalate borate (LiDFOB), lithium bis(oxalate borate) (LiBOB), lithium difluorophosphate (LiPO2F2), lithium difluorooxalate phosphate (LiDFOP), and lithium tetrafluorooxalate phosphate (LiTFOP).

[0079] Electrolyte salts can be analyzed and identified using techniques such as infrared spectroscopy, nuclear magnetic resonance, and mass spectrometry.

[0080] Interface wetting agents also include electrolyte salts, which are typically dispersed or dissolved in ionic liquids and diluents to form a homogeneous system. The electrolyte salts, together with the ionic liquids and diluents, can form an electrolyte-like interface wetting agent, filling the interparticle voids of the positive electrode along with the ionic liquid and diluent, thus promoting ion transport.

[0081] In some embodiments, the mass ratio of the ionic liquid to the electrolyte salt is 1:(0.5-2), optionally 1:(0.5-1), for example, any one of 1:0.5, 1:1, 1:1.5, 1:2, or any range between the two. In the actual preparation of the positive electrode, the electrolyte salt is typically dispersed in a composition of the ionic liquid and a diluent to form an interface wetting agent. The molar concentration of the electrolyte salt in the interface wetting agent can be set to 0.5M to 2M, for example, any one of 0.5M, 1M, 1.5M, 2M, or any range between the two.

[0082] The ratio between the ionic liquid and the electrolyte salt can be analyzed using mass spectrometry or nuclear magnetic resonance (NMR). At a specific electrolyte salt mass, ion transport can be effectively promoted, thereby increasing the ionic conductivity of the positive electrode.

[0083] In some embodiments, the interface wetting agent has a mass content of 1% to 10% in the positive electrode active layer, optionally 3% to 6%, for example, any one of 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, or any range between two. At this content, the interface wetting agent can fully fill the gaps between the particles of the positive electrode, reduce voids, and promote ion transport.

[0084] In some embodiments, the positive electrode active material includes one or more of lithium phosphates having an olivine structure and their modified compounds, lithium transition metal oxides and their modified compounds. Examples of lithium phosphates having an olivine structure include lithium iron phosphate (such as LiFePO4, i.e., LFP), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium iron manganese phosphate, and lithium iron manganese phosphate and carbon composites, wherein carbon can serve as a coating layer for the relevant composite material. Examples of lithium transition metal oxides may include lithium cobalt oxides (such as LiCoO2), lithium nickel oxides (such as LiNiO2), lithium nickel cobalt oxides, lithium manganese cobalt oxides, lithium nickel manganese oxides, and lithium nickel cobalt manganese oxides [such as LiNi]. 1 / 3 Co 1 / 3 Mn 1 / 3 O2(NCM333), LiNi 0.5 Co 0.2 Mn 0.3 O2(NCM523), LiNi 0.5 Co 0.25 Mn 0.25 O2(NCM211), LiNi 0.6 Co 0.2 Mn 0.2 O2(NCM622), LiNi 0.8 Co 0.1 Mn 0.1 O2 (NCM811), lithium nickel cobalt aluminum oxide (such as LiNi) 0.85 Co 0.15 Al 0.05 O2), lithium niobium oxides (such as lithium niobate), lithium titanium oxides (such as Li4Ti5O) 12 One or more of the following: and their modified compounds. These positive electrode active materials may be used alone or in combination of two or more. Understandably, these positive electrode active materials may contain various coating layers, such as carbon coating layers. The mass content of the positive electrode active material in the positive electrode active layer may include 60% to 80%, optionally 70% to 80%, for example, any one of 60%, 65%, 70%, 75%, 80%, or a range between any two.

[0085] In the positive electrode active layer, these positive electrode active materials are in contact with the interface wetting agent, and ions in the positive electrode active materials can be transported through the ionic liquid in the interface wetting agent. Furthermore, the reactivity between these positive electrode active materials and the interface wetting agent is low, allowing them to coexist stably.

[0086] In some embodiments, the solid electrolyte includes one or more of sulfide solid electrolytes, halide solid electrolytes, oxide solid electrolytes, and polymer solid electrolytes, optionally including sulfide solid electrolytes. Sulfide solid electrolytes include one or more of Li6PS5Cl, Li2S-GeS2, Li2S-P2S5, Li2S-SiS2, and Li2S-MeS2-P2S5 (Me = Si, Ge, Sn, Al, etc.). Halide solid electrolytes include one or more of Li3YCl6, Li3InCl6, Li3ErCl6, Li3ScCl6, Li3HoCl6, Li2MnCl4, Li2MnCl5, and Li6FeCl8. Oxide solid electrolytes include lithium oxide garnet (Li7La3Zr2O). 12 The solid electrolyte comprises one or more of the following: LLZO, tin oxide (SnO2), and bismuth oxide (Bi2O3). Polymer solid electrolytes include one or more of polyethylene oxide electrolytes, polycarbonate electrolytes, and polysiloxane electrolytes. The mass content of the solid electrolyte in the positive electrode active layer can include 10% to 30%, optionally 15% to 25%, for example, any one of 10%, 15%, 19%, 20%, 25%, and 30%, or a range between any two.

[0087] The solution proposed in this application is applicable to various solid electrolytes, and it is particularly effective in improving the ionic conductivity of positive electrode sheets, including those containing sulfide solid electrolytes. In the positive electrode active layer, the solid electrolyte and the interface wetting agent are in contact, and ions can be transported between the solid electrolyte and the positive electrode active material through the ionic liquid in the interface wetting agent.

[0088] The Dv50 of solid electrolytes ranges from 1 μm to 10 μm, for example, any point value or a range between any two of the following: 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, and 10 μm. For particle size distribution of materials, it is usually expressed as the percentage of particles within different particle size ranges. There are various benchmarks for determining particle size distribution, such as number distribution, length distribution, area distribution, volume distribution, and weight distribution. Dv50 is a specific particle size distribution based on volume distribution, also known as the median particle size, which refers to the particle size at which the cumulative volume distribution is 50%, indicating that 50% of the particles have a diameter greater than this value, and 50% of the particles have a diameter less than this value. The Dv50 of particles can be obtained by referring to GB / T19077-2016 / ISO 13320:2009 "Particle size distribution - Laser diffraction method".

[0089] The embodiments of this application can use solid electrolytes with micron-sized particles, which have short ion migration paths, which helps to reduce the resistance to ion migration and improve ion conductivity.

[0090] In some embodiments, the positive electrode active layer further includes a conductive agent. The conductive agent may include one or more of vapor-grown carbon fiber (VGCF), superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers. The mass content of the conductive agent in the positive electrode active layer may be 0.5% to 5%, for example, it may be any one of 0.5%, 1%, 2%, 3%, 4%, and 5%, or any range between two values.

[0091] In some embodiments, the positive electrode active layer may optionally include a binder. The binder may include one or more of the following: polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), PVDF-tetrafluoroethylene-propylene terpolymer, PVDF-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, fluorinated acrylate resin, polyamide (PA), polyacrylonitrile (PAN), polyacrylate, polyethylene ether, polymethyl methacrylate (PMMA), polyhexafluoropropylene, and styrene-butadiene rubber (SBR). The mass content of the binder in the positive electrode active layer may be 0.001% to 2%, for example, any one of 0.001%, 0.01%, 0.1%, 0.5%, 1%, or 2%, or a range between any two.

[0092] In some embodiments, the positive current collector includes two surfaces opposite each other in its own thickness direction, and the positive active layer can be disposed on either or both of the opposite surfaces of the positive current collector. The positive current collector includes one or more of metal foil and composite current collector. For example, aluminum foil can be used as the metal foil. The composite current collector may include a polymer material substrate and a metal layer formed on at least one surface of the polymer material substrate. The composite current collector can be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate [such as polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.].

[0093] The positive electrode sheet can be prepared by the following method:

[0094] The components used to prepare the positive electrode sheet, such as the positive electrode active material, solid electrolyte, interface wetting agent, conductive agent, and any other components, are mixed, film-formed, and pressed to obtain the positive electrode film. The positive electrode film is then combined with a positive electrode current collector to obtain the positive electrode sheet.

[0095] Alternatively, the components used to prepare the positive electrode sheet, such as the positive electrode active material, solid electrolyte, interface wetting agent, conductive agent and any other components, are mixed to form a positive electrode slurry. The positive electrode slurry is then coated onto the positive electrode current collector and cold-pressed to obtain the positive electrode sheet.

[0096] Alternatively, the positive electrode active material, solid electrolyte, conductive agent, and any other components are mixed, film-formed, and pressed to obtain the positive electrode membrane. An interface wetting agent is sprayed onto the positive electrode membrane, and then the positive electrode membrane is bonded to the positive electrode current collector; or the positive electrode membrane is bonded to the positive electrode current collector, and then the interface wetting agent is sprayed onto the positive electrode membrane.

[0097] Alternatively, a positive electrode active material, a solid electrolyte, a conductive agent, a solvent, and any other components can be mixed to form a positive electrode slurry. The positive electrode slurry is then coated onto a positive electrode current collector, dried, and cold-pressed to obtain a positive electrode sheet. Finally, an interface wetting agent is sprayed onto the positive electrode sheet.

[0098] Understandably, an interface wetting agent can be introduced during the preparation of the positive electrode sheet using any of the methods described above; alternatively, a positive electrode sheet without an interface wetting agent can be prepared first, and the interface wetting agent can be sprayed onto the positive electrode sheet at any stage after the positive electrode sheet is prepared and before battery assembly (e.g., battery stacking).

[0099] In this embodiment, a diluent is used to dilute the ionic liquid, which reduces the viscosity and improves the fluidity of the ionic liquid. Therefore, during the preparation of the positive electrode sheet, the ionic liquid can effectively fill the gaps between the particles of the positive electrode sheet, allowing ions inside the positive electrode sheet to be rapidly transported between the positive active material particles and the solid electrolyte particles through the ionic liquid in the particle gaps, thereby effectively improving the ionic conductivity of the positive electrode sheet.

[0100] [Negative electrode plate]

[0101] In some embodiments, the negative electrode sheet of this application includes one or more of metallic lithium and lithium alloys, wherein the lithium alloy includes one or more of lithium-indium alloy, lithium-silicon alloy, lithium-tin alloy, and lithium-aluminum alloy. Metallic lithium and lithium alloys can be directly used as negative electrode sheets.

[0102] In other embodiments, the negative electrode sheet may include a negative current collector and a negative active layer disposed on at least one side of the negative current collector, the negative active layer including a negative active material, a conductive agent, and a binder.

[0103] In some embodiments, the negative electrode active material includes one or more of graphite (artificial graphite, natural graphite), soft carbon, hard carbon, silicon-based materials, tin-based materials, and titanium-based materials. Silicon-based materials may include one or more of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may include one or more of elemental tin, tin oxide compounds, and tin alloys. Titanium-based materials may include lithium titanate. It is understood that this application is not limited to these materials, and other materials that can be used as negative electrode active materials in batteries may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0104] The mass content of the negative electrode active material in the negative electrode active layer can be 70% to 98%, or 90% to 98%, for example, any one of the values ​​of 70%, 75%, 80%, 85%, 90%, 92%, 94%, 96%, 98%, or any range between two.

[0105] In some embodiments, the conductive agent in the negative electrode active layer may include one or more of vapor-grown carbon fiber (VGCF), superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers. The mass content of the conductive agent in the negative electrode active layer may be 0.5% to 5%, for example, it may be any one of 0.5%, 1%, 2%, 3%, 4%, and 5%, or any range between two values.

[0106] In some embodiments, the binder in the negative electrode active layer may include one or more of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), PVDF-tetrafluoroethylene-propylene terpolymer, PVDF-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, fluorinated acrylate resin, polyamide (PA), polyacrylonitrile (PAN), polyacrylate, polyethylene ether, polymethyl methacrylate (PMMA), polyhexafluoropropylene, and styrene-butadiene rubber (SBR). The mass content of the binder in the negative electrode active layer may be 0.001% to 2%, for example, any one of 0.001%, 0.01%, 0.1%, 0.5%, 1%, or 2%, or a range between any two.

[0107] In some embodiments, the negative electrode current collector includes two surfaces opposite each other in its own thickness direction, and the negative electrode active layer can be disposed on either or both of the opposite surfaces of the negative electrode current collector. The negative electrode current collector includes one or more of metal foil and composite current collector. For example, aluminum foil can be used as the metal foil. The composite current collector may include a polymer material substrate and a metal layer formed on at least one surface of the polymer material substrate. The composite current collector can be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate [such as polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.].

[0108] In some implementations, the negative electrode sheet can be prepared in the following manner:

[0109] The components used to prepare the negative electrode sheet, such as the negative electrode active material, binder, and conductive agent (which may also include any other components), are dispersed in a solvent (e.g., water) to form a negative electrode slurry. The negative electrode slurry is coated on at least one side of the negative electrode current collector, and after drying, cold pressing and other processes, the negative electrode sheet can be obtained.

[0110] [Solid electrolyte]

[0111] The solid-state battery cell in this application includes a solid electrolyte, which is typically used in the form of a membrane, i.e., a solid electrolyte membrane. The solid electrolyte membrane is disposed between the positive and negative electrode plates and is in contact with both plates. During battery charging and discharging, active ions move back and forth between the positive and negative electrode plates, inserting and extracting. The solid electrolyte membrane acts as a transporter of ions between the positive and negative electrode plates.

[0112] The solid electrolyte membrane in this application includes one or more of sulfide solid electrolytes, halide solid electrolytes, oxide solid electrolytes, and polymer solid electrolytes, and optionally includes sulfide solid electrolytes. Sulfide solid electrolytes include one or more of Li6PS5Cl, Li2S-GeS2, Li2S-P2S5, Li2S-SiS2, and Li2S-MeS2-P2S5 (Me = Si, Ge, Sn, Al, etc.). Halide solid electrolytes include one or more of Li3YCl6, Li3InCl6, Li3ErCl6, Li3ScCl6, Li3HoCl6, Li2MnCl4, Li2MnCl5, and Li6FeCl8. Oxide solid electrolytes include lithium oxide garnet (Li7La3Zr2O). 12This includes one or more of the following: LLZO, tin oxide (SnO2), and bismuth oxide (Bi2O3). Polymer solid electrolytes include one or more of the following: polyethylene oxide electrolytes, polycarbonate electrolytes, and polysiloxane electrolytes.

[0113] To improve the compatibility between the solid electrolyte membrane and the electrode, the solid electrolyte membrane can have the same or similar properties as the solid electrolyte in the positive electrode active layer.

[0114] The Dv50 of the solid electrolyte is 1μm to 10μm, for example, any point value or a range between any two of 1μm, 2μm, 3μm, 4μm, 5μm, 6μm, 7μm, 8μm, 9μm, and 10μm.

[0115] Solid electrolyte membranes can be prepared by the following method:

[0116] A solid electrolyte is mixed with a binder to form a membrane of suitable thickness. In the solid electrolyte membrane, the mass of the binder can be 0.5% to 5%, for example, any one of 0.5%, 1%, 2%, 3%, 4%, or 5%, or a range between any two. The binder in the solid electrolyte membrane includes one or more of the following: polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), PVDF-tetrafluoroethylene-propylene terpolymer, PVDF-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, fluorinated acrylate resin, polyamide (PA), polyacrylonitrile (PAN), polyacrylate, polyethylene ether, polymethyl methacrylate (PMMA), polyhexafluoropropylene, and styrene-butadiene rubber (SBR).

[0117] Alternatively, during battery assembly, solid electrolyte powder can be placed between the negative and positive electrode plates, and pressure can be applied to assemble the battery. At the same time, the solid electrolyte changes from a powder state to a film.

[0118] [Outer Packaging]

[0119] Solid-state battery cells may include an outer packaging that can be used to encapsulate the positive electrode, negative electrode, and solid electrolyte membrane.

[0120] The outer packaging can be a hard shell, such as a hard plastic shell, aluminum shell, or steel shell; or it can be a soft package, such as a pouch. The material of the soft package can be plastic, such as polypropylene, polybutylene terephthalate, and polybutylene succinate.

[0121] The outer packaging can be cylindrical, square, or any other shape. For example, Figure 2 shows a solid-state battery cell with a square outer packaging structure as an example.

[0122] Referring to Figure 3, the outer packaging may include a housing 01 and a cover plate 02. The housing 01 may include a base plate and side plates connected to the base plate, the base plate and side plates forming a receiving cavity. The housing 01 has an opening communicating with the receiving cavity, and the cover plate 02 can be placed over the opening to close the receiving cavity. A positive electrode, a negative electrode, and a solid electrolyte membrane can be stacked to form an electrode assembly 03. One or more electrode assemblies 03 are encapsulated within the receiving cavity.

[0123] [Solid-state battery cell]

[0124] In this embodiment, the solid-state battery cell can be a rechargeable battery, which refers to a battery cell that can be recharged after discharge to reactivate the active materials and continue to be used. Optionally, the solid-state battery cell in this embodiment is an all-solid-state battery, and more preferably an all-solid-state lithium-ion battery.

[0125] The solid-state battery cell in this application embodiment includes the above-mentioned positive electrode sheet. The positive electrode sheet has high ion transport performance, which can reduce battery resistance and fully utilize the capacity of the positive electrode sheet. Therefore, the battery containing the positive electrode sheet exhibits high first-efficiency and improved cycle performance.

[0126] Solid-state battery cells can be assembled as follows: stack them in the order of negative electrode - solid electrolyte membrane - positive electrode, and apply pressure to make the positive electrode and negative electrode in close contact with the solid electrolyte membrane.

[0127] Alternatively, the materials can be added into the mold in the order of "negative electrode - solid electrolyte (powder) - positive electrode", and pressure can be applied to compact each time a new material is added into the mold.

[0128] [Battery Device]

[0129] This application provides a battery apparatus including multiple solid-state battery cells. Specifically, the battery apparatus mentioned in the embodiments of this application may include one or more battery cell assemblies for providing voltage and capacity. A battery cell assembly may include multiple solid-state battery cells, which are connected in series, parallel, or mixed connections via a busbar.

[0130] The solid-state battery cell of this application embodiment has good cycle performance. Therefore, applying the battery cell to a battery device can help improve the cycle performance of the battery device and extend the service life of the battery device.

[0131] In some implementations, a battery cell assembly is typically formed by arranging multiple battery cells.

[0132] As an example, a battery cell assembly can be a battery module, which is formed by arranging and fixing multiple battery cells together to form an independent module. As another example, a battery module can be formed by bundling multiple battery cells together with cable ties.

[0133] In some implementations, the battery device may be a battery pack, which includes a housing and one or more individual battery cells housed within the housing.

[0134] As an example, the battery cell assembly can be a battery module, and the battery cell assembly can be housed in the housing by fixing the battery module in the housing.

[0135] As an example, battery cell assemblies can also be housed in a housing by directly fixing multiple battery cells to the housing.

[0136] 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.

[0137] 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.

[0138] 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.

[0139] The technical solutions described in the embodiments of this application are applicable to various battery devices that use individual battery cells, such as mobile phones, portable devices, laptops, electric vehicles, electric toys, power tools, vehicles, ships, and spacecraft. For example, spacecraft include airplanes, rockets, space shuttles, and spacecraft.

[0140] [Energy Storage Device]

[0141] This application provides an energy storage device, including multiple solid-state battery cells or multiple battery devices, wherein the solid-state battery cells or battery devices are used to store or provide electrical energy.

[0142] The aforementioned solid-state battery cells and battery devices with good cycle performance are used to store or provide electrical energy for energy storage devices, which can extend the service life of energy storage devices.

[0143] In some implementations, the energy storage device includes one or more battery clusters to increase the voltage and capacity of the energy storage device. A battery cluster may include multiple battery units connected in series via a busbar to increase the voltage of the energy storage device. When the energy storage device includes multiple battery clusters, the battery clusters are connected in parallel to increase the capacity of the energy storage device.

[0144] Energy storage devices can be used in energy storage power stations, wind power generation systems, solar power generation systems, mobile power systems, or temporary power supply systems. Energy storage devices can store electrical energy as needed and output it when appropriate. For example, an energy storage device can store electrical energy during off-peak hours and provide power to relevant users or electrical equipment during peak hours. The energy storage system provided in this application embodiment can be any power system that requires energy storage devices.

[0145] In some implementations, the energy storage device is an energy storage container or an energy storage cabinet.

[0146] In some implementations, the energy storage device may include a cabinet and one or more battery clusters housed within the cabinet.

[0147] In some implementations, the energy storage device may include modules such as a thermal management module, a main control module, a central control module, a power distribution module, and a fire protection module.

[0148] As an example, the thermal management module may include a liquid cooling unit that supplies coolant to each battery device via piping to regulate the temperature of the individual battery cells.

[0149] As an example, the main control module can serve as the battery management unit for the battery cluster, used to monitor and manage the battery cluster. The main control module can monitor information such as the current, voltage, power, or temperature of the battery cluster. For instance, it can control the charging and discharging current and voltage of the battery cluster. The main control module includes a slave battery management unit (SBMU), a fusion switch, and other modules.

[0150] As an example, the central control module can serve as the battery management unit for an energy storage device, used to monitor and manage the device. The central control module can monitor information such as the energy storage device's current, voltage, power, state of charge, or temperature. For instance, it can control the charging and discharging current and voltage of the energy storage device. As an example, the central control module includes modules such as an Insulation Monitoring Module (IMM), a Master Battery Management Unit (MBMU), an Ethernet (ETH) module, and a fiber optic conversion module.

[0151] As an example, the fire protection module includes a control panel, detectors, alarm devices, etc., used to detect, alarm, or extinguish fires in the energy storage system.

[0152] As an example, a power distribution module can be used to distribute power to modules in an energy storage device that require electricity.

[0153] [Electrical appliances]

[0154] This application provides an electrical device, including multiple solid-state battery cells or multiple battery devices, wherein the solid-state battery cells or battery devices are used to store or provide electrical energy.

[0155] The aforementioned solid-state battery cells and battery devices with good cycle performance can be used as power sources for electrical devices or as energy storage units for electrical devices, thereby extending the service life of electrical devices.

[0156] Electrical devices may include, but are not limited to, mobile devices (such as mobile phones, laptops, etc.), electric vehicles (such as 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.

[0157] The embodiments of this application are described in detail below. The embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they are performed in accordance with the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0158] Example 1

[0159] 1. Positive electrode plate

[0160] The positive electrode active material NCM811, the conductive agent VGCF, the solid electrolyte Li6PS5Cl (Dv50 about 5μm) and the interface wetting agent are mixed in a mass ratio of 75:1:19:5 to obtain the positive electrode slurry. The positive electrode slurry is coated on both sides of the aluminum foil, and after cold pressing and cutting, the positive electrode sheet is obtained.

[0161] The interface wetting agent includes an ionic liquid Py13FSI, a diluent DMS, and a lithium salt LiFSI in a mass ratio of 1:0.3:1. The interface wetting agent is obtained by mixing the materials in the specified proportions.

[0162] 2. Negative electrode plate

[0163] One indium sheet and one lithium sheet, each with a thickness of 8μm.

[0164] 3. Solid electrolyte

[0165] Micron-sized (Dv50 approximately 5μm) Li6PS5Cl particle powder.

[0166] 4. Battery assembly

[0167] The relevant materials are added into the mold in the order of "indium sheet - lithium sheet - solid electrolyte - positive electrode sheet". Each time a new material is added into the mold, it must be compacted with 4 tons of pressure.

[0168] Example 2

[0169] The difference between this embodiment and Embodiment 1 is that the mass ratio of ionic liquid Py13FSI, diluent DMS, and lithium salt LiFSI in the interface wetting agent is adjusted to 2:0.5:1.

[0170] Example 3

[0171] The difference between this embodiment and Embodiment 1 is that the mass ratio of the ionic liquid Py13FSI, the diluent DMS, and the lithium salt LiFSI in the interface wetting agent is adjusted to 1:1:1.

[0172] Example 4

[0173] The difference between this embodiment and Embodiment 1 is that the mass ratio of ionic liquid Py13FSI, diluent DMS, and lithium salt LiFSI in the interface wetting agent is adjusted to 1:5:1.

[0174] Example 5

[0175] The difference between this embodiment and Embodiment 1 is that the mass ratio of ionic liquid Py13FSI, diluent DMS, and lithium salt LiFSI in the interface wetting agent is adjusted to 2:0.1:1.

[0176] Example 6

[0177] The difference between this embodiment and Example 1 is that the diluent DMS is replaced with an equal mass of ethyl acetate.

[0178] Example 7

[0179] The difference between this embodiment and Embodiment 1 is that the ionic liquid Py13FSI is replaced with an equal mass of EMIMTFSI.

[0180] Comparative Example 1

[0181] The difference between this comparative example and Example 1 is that the positive electrode does not contain an interface wetting agent. Specifically, the preparation method of the positive electrode in this comparative example is as follows: the positive active material NCM811, the conductive agent VGCF, and the solid electrolyte Li6PS5Cl are mixed in a mass ratio of 75:1:19, coated on both sides of an aluminum foil, and then cold-pressed and cut to obtain the positive electrode.

[0182] Comparative Example 2

[0183] The difference between this comparative example and Example 1 is that the interface wetting agent does not contain a diluent. Specifically, in this comparative example, the mass ratio of the ionic liquid Py13FSI, the diluent DMS, and the lithium salt LiFSI in the interface wetting agent is 1:0:0.2.

[0184] Performance tests were conducted as follows, all under normal temperature conditions (20℃~25℃), without applying pressure during the tests. The battery capacities of all embodiments and comparative examples were designed to be 185mAh / g~190mAh / g.

[0185] 1) Ionic conductivity

[0186] The prepared positive electrode sheet was cut into a 10mm diameter circle and fixed inside an insulating sleeve with an inner diameter of 10mm by stainless steel pillars on both sides. The outer side was connected to an electrochemical workstation for electrochemical impedance spectroscopy (EIS) testing. The test voltage was 10mV, and the test frequency range was 10... 6 Hz~0.1Hz. Based on the comparison of the obtained impedance spectrum, when Z (the imaginary part of the impedance) is 0, the value of Z' (the real part of the impedance) can be regarded as the ionic impedance Ri of this positive electrode. The ionic conductivity σ is calculated from the impedance and the thickness and area of ​​the electrode: σ=d / RiS (d is the thickness of the positive electrode, and S is the measured area of ​​the positive electrode).

[0187] 2) First effect

[0188] Charge at a constant current of 0.1C to 4.3V, then switch to constant voltage charging until the current is less than 0.05C. Record the first charge capacity C1 at 0.1C. Then discharge at 0.1C to 2.5V and record the first discharge capacity C2 at 0.1C. First efficiency = C2 / C1 × 100%.

[0189] 3) Cyclic performance

[0190] Charge the capacitor to 4.3V at a constant current of 0.33C, then switch to constant voltage charging until the current is less than 0.05C. Discharge it to 2.5V at 0.33C, and record the initial discharge capacity C1 at 0.33C. Repeat this cycle 60 times, and record the discharge capacity after 60 cycles.

[0191] Table 1

[0192] The test results are shown in Table 1. Results Explanation: Examples 1-5, by adding an interfacial wetting agent containing a diluent and ionic liquid to the positive electrode, exhibited higher ionic conductivity compared to Comparative Examples 1 and 2, which did not add an interfacial wetting agent or whose interfacial wetting agent did not contain a diluent. This is mainly because diluting the ionic liquid with a diluent reduces its viscosity and increases its fluidity, allowing it to effectively fill the gaps between the particles in the positive electrode. Thus, the contact between the positive active material particles and the solid electrolyte particles is no longer a point contact between solids; ions inside the positive electrode can be rapidly transported between the positive active material particles and the solid electrolyte particles through the ionic liquid in the particle gaps, thereby effectively improving the ion transport performance of the positive electrode. Furthermore, the ion-conducting ability of the ionic liquid is also improved after dilution with the diluent, which also contributes to improving the ionic conductivity of the positive electrode.

[0193] In Comparative Example 1, the positive electrode lacked an interfacial wetting agent, resulting in numerous voids between the particles, hindering ion transport. While Comparative Example 2 incorporated an interfacial wetting agent containing an ionic liquid, the agent's poor flowability prevented effective filling of these voids, thus limiting its impact on improving the ionic conductivity of the positive electrode.

[0194] Corresponding to the ionic conductivity, after the ionic conductivity of the positive electrode sheet was improved in Examples 1 to 3, the battery's initial efficiency and cycle performance were also greatly improved compared with Comparative Examples 1 and 2.

[0195] In addition, Examples 6 and 7 also exhibited performance comparable to Example 1.

[0196] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. 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, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. A solid-state battery cell, characterized in that, The device includes a positive electrode sheet, which includes a positive current collector and a positive active layer disposed on at least one side of the positive current collector. The positive active layer contains a positive active material, a solid electrolyte, and an interface wetting agent, which includes an ionic liquid and a diluent.

2. The solid-state battery cell according to claim 1, characterized in that, The diluent includes one or more of the following: thioether compounds, saturated ester compounds, polyether polyol compounds, and sulfoxide compounds.

3. The solid-state battery cell according to claim 2, characterized in that, The sulfide compounds include one or more of dimethyl sulfide, dimethyl disulfide, diphenyl sulfide, and diethyl sulfide; and / or, The saturated ester compounds include one or more of methyl formate, ethyl formate, propyl formate, butyl formate, methyl acetate, ethyl acetate, propyl acetate, isoamyl acetate, and ethyl hexanoate; and / or, The polyether polyol includes one or more of polypropylene oxide diol, polytetrahydrofuran diol, and tetrahydrofuran-propylene oxide copolydiol; and / or The sulfoxide compounds include one or more of thionyl chloride and dimethyl sulfoxide.

4. The solid-state battery cell according to any one of claims 1 to 3, characterized in that, The anions contained in the ionic liquid include one or more of bis(fluorosulfonyl)imide anion, bis(trifluoromethanesulfonyl)imide anion, and trifluoromethanesulfonic acid anion.

5. The solid-state battery cell according to any one of claims 1 to 4, characterized in that, The cations contained in the ionic liquid include one or more of the following: pyrrolidine cations, imidazole cations, piperidine cations, pyridine cations, and thiophene cations.

6. The solid-state battery cell according to any one of claims 1 to 5, characterized in that, The mass ratio of the ionic liquid to the diluent is 1:(0.05-5).

7. The solid-state battery cell according to any one of claims 1 to 6, characterized in that, The mass ratio of the ionic liquid to the diluent is 1:(0.2-3).

8. The solid-state battery cell according to any one of claims 1 to 7, characterized in that, The mass ratio of the ionic liquid to the diluent is 1:(0.2~1).

9. The solid-state battery cell according to any one of claims 1 to 8, characterized in that, The interface wetting agent also includes electrolyte salts.

10. The solid-state battery cell according to claim 9, characterized in that, The mass ratio of the ionic liquid to the electrolyte salt is 1:(0.5-2).

11. The solid-state battery cell according to claim 9 or 10, characterized in that, The mass ratio of the ionic liquid to the electrolyte salt is 1:(0.5~1).

12. The solid-state battery cell according to any one of claims 1 to 11, characterized in that, The interface wetting agent has a mass content of 1% to 10% in the positive electrode active layer.

13. The solid-state battery cell according to any one of claims 1 to 12, characterized in that, The interface wetting agent has a mass content of 3% to 6% in the positive electrode active layer.

14. A positive electrode plate, characterized in that, It includes a positive current collector and a positive active layer disposed on at least one side of the positive current collector. The positive active layer contains a positive active material, a solid electrolyte, and an interface wetting agent, wherein the interface wetting agent includes an ionic liquid and a diluent.

15. A battery device, characterized in that, It includes any one of the solid-state battery cells described in claims 1 to 13.

16. An energy storage device, characterized in that, It includes a solid-state battery cell according to any one of claims 1 to 13 or a battery device according to claims 15, wherein the solid-state battery cell or the battery device is used to store or provide electrical energy.

17. An electrical appliance, characterized in that, It includes a solid-state battery cell according to any one of claims 1 to 13 or a battery device according to claims 15, wherein the solid-state battery cell or the battery device is used to store or provide electrical energy.

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