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

Abstract

A solid-state metal battery cell and a preparation method therefor, a battery device, and an electric device. The solid-state metal battery cell comprises a positive electrode sheet, a negative electrode sheet, and a solid-state electrolyte layer located between the positive electrode sheet and the negative electrode sheet. A polyionic liquid layer is provided between the solid-state electrolyte layer and the negative electrode sheet, and the material of the polyionic liquid layer comprises a polyionic liquid and a metal salt. In the solid-state metal battery cell, on the basis that the polyionic liquid layer comprises a polyionic liquid and a metal salt, not only the active metal ion conduction in the polyionic liquid layer can be realized, but side reactions between the negative electrode sheet metal and the solid-state electrolyte layer of the solid-state metal battery cell, and the risk of dendrite growth can also be reduced, thereby achieving a good charge-discharge performance.

Description

Solid-state metal battery cells and their preparation methods, battery devices, and electrical devices.

[0001] This application claims priority to Chinese Patent Application No. 202411734355.3, filed on November 29, 2024, entitled "Solid-state metal battery cell and preparation method thereof, battery device, and power-consuming device", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application belongs to the field of battery technology, specifically relating to a solid metal battery cell and its preparation method, battery device, and power-consuming device. Background Technology

[0003] With the booming development of new energy vehicles, battery drive systems have become an important factor affecting the performance and cost of new energy vehicles. Due to their high energy density, low memory effect, and high operating voltage, batteries have become the preferred power source for battery drive systems.

[0004] For solid metal batteries, side reactions are prone to occur between the negative electrode metal and the solid electrolyte during operation. Moreover, the volume expansion of the negative electrode metal during charging and discharging can easily lead to poor contact at the solid-solid interface, thereby accelerating dendrite formation, resulting in battery capacity loss and affecting charging and discharging performance. Summary of the Invention

[0005] The purpose of this application is to provide a solid metal battery cell and its preparation method, battery device, and power supply device, aiming to solve the technical problem of how to improve the charge and discharge performance of solid metal battery cells.

[0006] To achieve the above-mentioned objectives, the technical solution adopted in this application is as follows:

[0007] In a first aspect, embodiments of this application provide a solid metal battery cell, including a positive electrode, a negative electrode, and a solid electrolyte layer located between the positive electrode and the negative electrode; wherein a polyionic liquid layer is disposed between the solid electrolyte layer and the negative electrode, and the material of the polyionic liquid layer includes a polyionic liquid and a metal salt.

[0008] The polyionic liquid layer between the negative electrode and the solid electrolyte layer contains both polyionic liquid and metal salt. The metal salt contains active metal ions, enabling the conduction of these ions within the polyionic liquid layer. The polyionic liquid, a polymer combining the advantages of both ionic liquids and polymers, overcomes the limitations of simple ionic liquids in terms of fluidity. Its stability reduces the risk of side reactions between the negative electrode metal and the solid electrolyte layer in solid-state metal battery cells. Furthermore, the polyionic liquid possesses flexibility and self-healing capabilities, mitigating the negative electrode volume expansion effect and reducing the risk of dendrite growth. Therefore, through the action of this polyionic liquid layer, solid-state metal battery cells can exhibit excellent discharge specific capacity and cycle stability, resulting in superior charge-discharge performance.

[0009] In some embodiments, the polyionic liquid includes acrylate-based polyionic liquids.

[0010] Acrylic ester polyionic liquids are polyionic liquids polymerized from polymerizable acrylate ionic liquid monomers, which can improve the charge and discharge performance of battery cells.

[0011] In some embodiments, the repeating unit of the acrylate polyionic liquid includes at least one of the following: 1-ethyl-3-acrylate imidazole bisfluorosulfonylimide salt, 1-ethyl-acrylate pyridine bis(trifluoromethanesulfonylimide) salt, 1-ethyl-acrylate pyridine bis(trifluoromethanesulfonylimide) salt, 1-ethyl-1-acrylate piperidine bis(trifluoromethanesulfonylimide) salt, 1-ethyl-1-acrylate pyrrolidine bis(trifluoromethanesulfonylimide) salt, and 1-ethyl-1-acrylate pyrrolidine bis(trifluoromethanesulfonylimide) salt.

[0012] The aforementioned acrylate-based polyionic liquids can not only improve the charge and discharge performance of battery cells, but are also widely available and easy to prepare.

[0013] In some embodiments, the molar ratio of the monomer raw material to the metal salt in the polyionic liquid is (8-1):1.

[0014] The polyionic liquid layer formed at the above ratio has good stability, flexibility and ionic conductivity.

[0015] In some embodiments, the material of the polyionic liquid layer further includes a non-polymerized ionic liquid.

[0016] By adding a certain amount of non-polymerized ionic liquid to the polyionic liquid layer, the ionic liquid properties can not only improve the overall ionic conductivity of the polyionic liquid layer, but also give it certain gel properties, thereby further improving the low-temperature cycling stability of the battery.

[0017] In some embodiments, the ionic liquid comprises at least one of 1-methyl-1-propylpyrrolidone bis(fluorosulfonyl)imide salt, 1-methyl-1-propylpyrrolidone bis(trifluoromethanesulfonyl)imide salt, lithium bis(fluorosulfonyl)imide salt tetraethylene glycol ester, lithium bis(trifluoromethanesulfonyl)imide salt tetraethylene glycol ester, 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide salt, and 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt.

[0018] And / or, the molar ratio of the monomer raw material in the polyionic liquid to the ionic liquid is (5-8-1):1.

[0019] The aforementioned types of ionic liquids and molar ratios, when used in the polyionic liquid layer between the negative electrode and the solid electrolyte layer, can significantly improve the low-temperature charge-discharge performance of solid metal battery cells.

[0020] In some embodiments, the thickness of the polyionic liquid layer is 10–50 μm.

[0021] The polyionic liquid layer of the aforementioned thickness can effectively reduce the risk of side reactions between the negative electrode metal and the solid electrolyte layer, as well as the negative electrode volume expansion effect.

[0022] In some embodiments, the solid metal battery cell includes a solid lithium metal battery cell, and the metal salt includes a lithium salt.

[0023] The solid-state lithium metal battery cells of this application have excellent energy density.

[0024] In some embodiments, the lithium salt includes at least one of lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium hexafluorophosphate, lithium perchlorate, and lithium tetrafluoroborate.

[0025] The aforementioned lithium salts, when used in the polyionic liquid layer of solid-state lithium metal battery cells, can give them excellent lithium-ion conductivity.

[0026] In some embodiments, the negative electrode sheet comprises a lithium metal sheet.

[0027] Lithium metal has high energy density, but it is prone to side reactions when it comes into contact with solid electrolyte during charging and discharging. Therefore, the solid metal battery cell of this application can not only make good use of the high energy density of lithium metal, but also reduce the side reactions between lithium metal and solid electrolyte layer and the risk of lithium metal expansion by the polyionic liquid layer, so that the battery cell has good charging and discharging performance.

[0028] In some embodiments, the material of the solid electrolyte layer includes at least one of a halide electrolyte and a sulfide electrolyte.

[0029] The solid electrolyte layer formed by the above-mentioned electrolyte materials has excellent ionic conductivity.

[0030] Secondly, embodiments of this application provide a method for preparing a solid-state metal battery cell, comprising:

[0031] A precursor solution is prepared, wherein the precursor solution comprises a polymerizable ionic liquid monomer and a metal salt;

[0032] The precursor solution is applied to the surface of the solid electrolyte layer away from the positive electrode, and then the surface of the solid electrolyte layer coated with the precursor solution is bonded to the negative electrode; or the precursor solution is applied to the surface of the negative electrode, and then the surface of the negative electrode coated with the precursor solution is bonded to the surface of the solid electrolyte layer away from the positive electrode.

[0033] The precursor solution between the negative electrode and the solid electrolyte layer is polymerized to form a polyionic liquid layer, thereby obtaining a solid metal battery cell.

[0034] This application embodiment involves in-situ polymerization of a polyionic liquid layer containing polyionic liquid and metal salt between the negative electrode and the solid electrolyte layer. This polyionic liquid layer provides stability to both the solid electrolyte layer and the negative electrode, reducing the risk of side reactions. Simultaneously, the in-situ polymerization of the polyionic liquid layer allows for better interfacial contact between the solid electrolyte layer and the negative electrode. Furthermore, the flexibility and self-healing ability of the polyionic liquid layer mitigate negative electrode volume expansion and reduce the risk of dendrite growth. Therefore, the solid metal battery cell prepared using this method exhibits excellent charge-discharge performance.

[0035] In some embodiments, the step of preparing the precursor solution includes: mixing the ionic liquid monomer and the metal salt in a molar ratio of (8-1):1, and then adding an initiator accounting for 1-5% of the mass of the ionic liquid monomer.

[0036] The precursor solution prepared according to the above proportions can polymerize well to form a polyionic liquid layer.

[0037] In some embodiments, the ionic liquid monomer includes acrylate ionic liquid monomers.

[0038] Acrylic ionic liquid monomers can be polymerized to form stable and flexible acrylic polyionic liquid materials.

[0039] In some embodiments, the acrylate ionic liquid monomer comprises at least one of the following: 1-ethyl-3-acrylate imidazole bisfluorosulfonylimide salt, 1-ethyl-acrylate pyridine bis(trifluoromethanesulfonylimide) salt, 1-ethyl-acrylate pyridine bis(trifluoromethanesulfonylimide) salt, 1-ethyl-1-acrylate piperidine bis(trifluoromethanesulfonylimide) salt, 1-ethyl-1-acrylate piperidine bis(trifluoromethanesulfonylimide) salt, and 1-ethyl-1-acrylate pyrrolidine bis(trifluoromethanesulfonylimide) salt.

[0040] The aforementioned monomers are widely available and easily obtained, and can be polymerized to form acrylate polyionic liquids.

[0041] In some embodiments, the polymerization reaction is carried out at a temperature of 60–80°C; and / or the polymerization reaction is carried out for a duration of 3–24 hours.

[0042] Under the above temperature and time conditions, the ionic liquid monomers can be fully polymerized in situ.

[0043] Thirdly, embodiments of this application provide a battery device, including a solid metal battery cell provided in the first aspect of embodiments of this application or a solid metal battery cell provided in the second aspect of embodiments of this application.

[0044] By using the solid metal battery cell provided in the embodiments of this application, based on the fact that the polyionic liquid layer between its negative electrode and solid electrolyte layer contains polyionic liquid and metal salt, the solid metal battery cell can have good discharge specific capacity and cycle stability through the action of the polyionic liquid layer, and such battery device has good charge and discharge performance.

[0045] Fourthly, embodiments of this application provide an electrical device, including a solid metal battery cell provided in the first aspect of this application, a solid metal battery cell provided in the second aspect of this application, or a battery device provided in the third aspect of this application, wherein the solid metal battery cell or the battery device is used to store or provide electrical energy.

[0046] Electrical devices that employ solid metal battery cells or battery devices provided in the embodiments of this application have good charging and discharging performance and can operate better.

[0047] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0048] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiments below. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0049] Figure 1 is a schematic diagram of a solid metal battery cell according to an embodiment of this application;

[0050] Figure 2 is an exploded view of the solid metal battery cell shown in Figure 1;

[0051] Figure 3 is a schematic diagram of one embodiment of the battery module of this application;

[0052] Figure 4 is a schematic diagram of one embodiment of the battery pack of this application;

[0053] Figure 5 is an exploded view of the battery pack shown in Figure 4.

[0054] Figure 6 is a schematic diagram of one embodiment of an electrical device that uses a solid metal battery as a power source according to the present application.

[0055] Explanation of reference numerals in the attached drawings: 10-cell battery; 11-casing; 12-top cover assembly; 13-electrode assembly; 20-battery module; 30-battery pack; 31-upper casing; 32-lower casing. Detailed Implementation

[0056] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0057] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0058] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0059] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0060] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0061] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces). "At least one" refers to one or more (including one, two, three, etc.).

[0062] In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0063] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0064] With the dwindling availability of traditional energy resources, the development of new energy storage devices is receiving increasing attention. Among these, secondary batteries are not only used in energy storage systems for hydropower, thermal power, wind power, and solar power plants, but are also widely applied in electric vehicles such as electric bicycles, electric motorcycles, and electric cars. As the application areas of secondary batteries as power batteries continue to expand, the market demand is also constantly increasing, while the performance requirements for these batteries are becoming increasingly stringent.

[0065] Solid-state batteries are batteries that use solid electrodes and solid electrolytes. Because solid-state battery technology uses solid electrolytes instead of traditional liquid electrolytes, it significantly improves the energy density of the battery. So-called metal-solid-state batteries are those where the negative electrode uses a metal as the active material; for example, lithium metal is considered one of the most promising candidates for improving energy density. However, when solid metals are matched with solid electrolytes, both theory and experiments have shown that side reactions occur, leading to a continuous increase in interfacial resistance and affecting battery performance. Simultaneously, during repeated charge and discharge cycles, the volume expansion of the negative electrode metal at the solid-solid contact interface leads to poor interfacial contact. Interfacial voids interfere with the transport of active metal ions and accelerate the formation of dendrites on the negative electrode, resulting in irreversible capacity loss in solid-metal batteries.

[0066] Based on this, this application embodiment modifies a polyionic liquid layer between the negative electrode and the solid electrolyte layer of the solid metal battery. The charge and discharge performance of the battery is improved through the action of the polyionic liquid layer. The specific technical solution is as follows.

[0067] Solid-state metal battery cells and their preparation methods

[0068] The first aspect of this application provides a solid-state metal battery cell. Specifically, it includes: (1) a positive electrode containing a positive active material; (2) a negative electrode; and (3) a solid electrolyte layer located between the positive and negative electrodes, containing a solid electrolyte for conducting the active metal ions of the battery. A polyionic liquid layer containing a polyionic liquid and a metal salt is disposed between the solid electrolyte layer and the negative electrode.

[0069] Ionic liquids are salts composed of cations and anions that are liquid at or near room temperature. They are also called low-temperature molten salts, room-temperature ionic liquids, or organic ionic liquids. Ionic liquids have outstanding advantages such as high conductivity and good stability. However, since they are liquid at room temperature, it is difficult to fabricate a functional film layer in solid-state batteries using only ionic liquids. The room temperature in the embodiments of this application generally refers to 20–25°C.

[0070] Poly(ionic liquids) (PILs) are a class of ionic liquid polymers formed by polymerizing polymerizable ionic liquid monomers. They have anionic and cationic groups on repeating units. Because they are polymers, they are generally solid at room temperature. They combine the excellent properties of ionic liquids and polymers, overcome the fluidity of ionic liquids, and have characteristics such as electrochemical stability and good ionic conductivity.

[0071] Metal salts are salts containing active metal ions, which are the active metal ions in solid-state metal battery cells. Because metal salts contain active metal ions, they enable the conduction of active metal ions in the polyionic liquid layer. For example, taking a lithium metal battery cell as an example, the positive electrode active material is lithium, and the metal salt can be a lithium metal salt.

[0072] Given that the negative electrode metal in current solid-state metal batteries is prone to side reactions with dendrites in the solid electrolyte, this application embodiment incorporates a polyionic liquid layer containing polyionic liquid and metal salt between the negative electrode sheet and the solid electrolyte layer. Due to the stability of the polyionic liquid, the risk of side reactions between the negative electrode metal and the solid electrolyte layer in the solid-state metal battery cell can be reduced. Furthermore, the solid-solid contact interface between the negative electrode and the solid electrolyte layer currently tends to accelerate dendrite growth during repeated charge-discharge processes. The polyionic liquid in this application embodiment possesses a certain degree of flexibility and self-healing ability, which can alleviate the negative electrode volume expansion effect and reduce the risk of negative electrode dendrite growth.

[0073] Therefore, the solid metal battery cell of this application embodiment, based on the effect of the polyionic liquid layer, can improve the battery's discharge specific capacity and cycle stability, thereby having excellent charge and discharge performance.

[0074] In some embodiments, the polyionic liquid includes acrylate-based polyionic liquids. Acrylate-based polyionic liquids refer to polyionic liquids polymerized from polymerizable acrylate-based ionic liquid monomers. They possess the advantages of good stability and flexibility of polyionic liquids and can stably bond with the negative electrode and solid electrolyte layer, thereby significantly improving the charge-discharge performance of battery cells.

[0075] In some embodiments, acrylate polyionic liquids may be polyionic liquids in which the organic cation contains imidazole, pyridine, pyrrole, piperidine, etc., and depending on the raw materials used, the repeating units include at least one of 1-ethyl-3-acrylate imidazole bisfluorosulfonylimide salt, 1-ethyl-acrylate pyridine bis(trifluoromethanesulfonylimide) salt, 1-ethyl-acrylate pyridine bis(trifluoromethanesulfonylimide) salt, 1-ethyl-1-acrylate piperidine bis(trifluoromethanesulfonylimide) salt, 1-ethyl-1-acrylate pyrrolidine bis(trifluoromethanesulfonylimide) salt, 1-ethyl-1-acrylate pyrrolidine bis(trifluoromethanesulfonylimide) salt, 1-ethyl-1-acrylate pyrrolidine bis(trifluoromethanesulfonylimide) salt, i.e., acrylate polyionic liquids include one or more repeating units (from ionic liquid monomer raw materials). For example, taking a repeating unit as an example, acrylate polyionic liquids may specifically include one of the following: 1-ethyl-3-acrylate imidazole bisfluorosulfonylimide salt polymer, 1-ethyl-acrylate pyridine bis(trifluoromethanesulfonylimide) salt polymer, 1-ethyl-acrylate pyridine bis(trifluoromethanesulfonylimide) salt polymer, 1-ethyl-acrylate pyrrole bis(trifluoromethanesulfonylimide) salt polymer, 1-ethyl-1-acrylate piperidine bis(trifluoromethanesulfonylimide) salt polymer, 1-ethyl-1-acrylate pyrrolidine bis(trifluoromethanesulfonylimide) salt polymer, and 1-ethyl-1-acrylate pyrrolidine bis(trifluoromethanesulfonylimide) salt polymer. These acrylate polyionic liquids not only improve the charge-discharge performance of battery cells but are also widely available and easy to prepare.

[0076] For example, 1-ethyl-3-acrylate imidazole trifluoromethanesulfonyl imide salt can be selected. These ionic liquid polymers can effectively reduce the risk of side reactions between the negative electrode metal and the solid electrolyte layer of solid metal battery cells.

[0077] In some embodiments, the molar ratio of monomer raw material to metal salt in the polyionic liquid is (8-1):1. Exemplarily, the molar ratio of monomer to metal salt in the polyionic liquid can be the molar ratio of repeating structural units formed after polymerization to metal salt, and the molar ratio of repeating structural units to metal salt can be 8:1, 6:1, 4:1, 1:1, etc. The polyionic liquid layer formed under the above ratios possesses good stability, flexibility, and ionic conductivity, thereby significantly improving the charge-discharge performance of solid-state metal battery cells.

[0078] In some embodiments, the material of the polyionic liquid layer also includes non-polymerized ionic liquids. Non-polymerized ionic liquids are used in contrast to polyionic liquids, which are polymerized from ionic liquid monomers. These monomers can polymerize due to their unsaturated double bonds, while non-polymerized ionic liquids are some commonly used, non-polymerizable ionic liquids. Adding a certain amount of non-polymerized ionic liquid to the polyionic liquid layer not only improves the overall ionic conductivity of the layer, but also, by dispersing these non-polymerized ionic liquids within the layer, imparts certain gel properties. This not only improves flexibility and ion transport performance but also further enhances the low-temperature cycling stability of the battery.

[0079] In some embodiments, the non-polymerized ionic liquids include at least one of the following: 1-methyl-1-propylpyrrolidine onium bisfluorosulfonylimide (Py13FSI), 1-methyl-1-propylpyrrolidine bis(trifluoromethanesulfonylimide) (Py13TFSI), lithium bis(fluorosulfonylimide) tetraethylene glycol ester (LiG4FSI), lithium bis(trifluoromethanesulfonylimide) tetraethylene glycol ester (LiG4TFSI), 1-ethyl-3-methylimidazolium bis(fluorosulfonylimide) (EMIMFSI), and 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonylimide) (EMIMTFSI). The addition of the above-mentioned ionic liquids to the polyionic liquid layer can significantly improve the low-temperature charge-discharge performance of solid-state metal battery cells.

[0080] In some implementations, the molar ratio of monomer raw materials to ionic liquid in polyionic liquid is (5-8-1):1. For example, the molar ratio of repeating structural units to non-polymerized ionic liquid can be 8:1, 7:1, 6:1, 5:1, etc. At these ratios, the use of ionic liquid in the polyionic liquid layer between the negative electrode and the solid electrolyte layer can significantly improve the low-temperature charge-discharge performance of solid-state metal battery cells.

[0081] In some embodiments, the thickness of the polyionic liquid layer is 10–50 μm. Exemplarily, the thickness of the polyionic liquid layer can be 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 45 μm, 50 μm, etc. Polyionic liquid layers of the above thicknesses can effectively reduce side reactions between the negative electrode metal and the solid electrolyte layer, as well as the risk of negative electrode volume expansion.

[0082] In some embodiments, the solid-state metal battery cell includes a solid-state lithium metal battery cell, and the metal salt includes a lithium salt. The solid-state lithium metal battery cell of this application embodiment has excellent energy density.

[0083] In some embodiments, the lithium salt includes at least one selected from lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium hexafluorophosphate, lithium perchlorate, and lithium tetrafluoroborate. The above-mentioned lithium salts, when used in the polyionic liquid layer of a solid-state lithium metal battery cell, can impart excellent lithium-ion conductivity.

[0084] In some embodiments, the negative electrode sheet includes a lithium metal sheet. Lithium metal has a high energy density, but it is prone to side reactions when in contact with a solid electrolyte during charging and discharging. Therefore, the solid metal battery cell of this application embodiment can not only make good use of the high energy density of lithium metal, but also the polyionic liquid layer can reduce the side reactions between lithium metal and the solid electrolyte layer and the risk of lithium metal expansion, so that the battery cell has excellent charge and discharge performance.

[0085] In some embodiments, the material of the solid electrolyte layer includes at least one of a halide electrolyte and a sulfide electrolyte. The solid electrolyte layer formed from the above-described electrolyte material has excellent ionic conductivity.

[0086] Sulfide electrolytes may include one or more of the following: silver-germanium sulfide type sulfide electrolytes, LGPS type sulfide electrolytes, and lithium sulfide-phosphorus pentasulfide complex type sulfide electrolytes. Among them, silver-germanium sulfide type electrolytes include those with the chemical formula Li... 6±s P 1-j A j S 5±s-t B t X 1±s Sulfide electrolytes, wherein 0≤j<1, 0≤t<1, 0≤s<1, A is selected from one or more elements from Ge, Si, Sn, and Sb, B is one or more elements from O, Se, and Te, and X is selected from one or more elements from Cl, Br, I, and F; LGPS type sulfide electrolytes include those with the chemical formula Li 10±δ5 Ge 1-g G g P 2-q Q q S 12-w W w The sulfide electrolytes, wherein 0≤δ5<1, 0≤g≤1, 0≤q≤2, 0≤w<1, G is selected from one or two elements from Si and Sn, Q is Sb, and W is selected from one or more elements from O, Se, Te, Cl, Br, I, and F; lithium sulfide pentaphosphine disulfide complex sulfide electrolytes include those with the chemical formula (100-uv)Li2S·uP2S5·vM m N nA sulfide electrolyte, where 0 < u < 100, 0 ≤ v < 100, 0 ≤ u + v < 100, 0 ≤ m < 4, 0 ≤ n < 6, M is selected from one or more elements of Li, B, Ge, Si, Sn, and Sb, and N is selected from one or more elements of S, Se, Te, O, Cl, Br, I, and F.

[0087] A halide electrolyte, including a metal halide electrolyte, with the chemical formula Li a MX b , where M is a metal element and X is a halogen element. For example, it can be: Li a MX4 (such as the positive spinel phases Li2MnCl4, Li2ZnCl4, etc. formed by divalent metal ions M, and the halide electrolytes LiYbF4, LiAlF4, etc. formed by trivalent and other valent metal ions M), Li a MX6 (such as Li3YCl6 and Li3YBr6, etc.) and Li a MX8 (such as Li6CoCl8, etc.).

[0088] In some embodiments, the positive electrode plate includes a positive electrode current collector and a positive electrode active layer provided on at least one surface of the positive electrode current collector. The positive electrode active layer contains a positive electrode active material, and the positive electrode active material may include positive electrode active materials known in the art for batteries. As an example, the positive electrode active material of a solid-state lithium metal battery may include at least one of the following materials: lithium phosphate with an olivine structure, lithium transition metal oxides, and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as battery positive electrode active materials can also be used. These positive electrode active materials can be used alone or in combination of two or more. Among them, examples of lithium transition metal oxides may include, but are not limited to, lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (which can also be abbreviated as NCM 333 ), LiNi 0.5 Co 0.2 Mn 0.3 O2 (which can also be abbreviated as NCM 523 ), LiNi 0.5 Co 0.25 Mn 0.25 O2 (which can also be abbreviated as NCM 211 ), LiNi 0.6 Co 0.2 Mn 0.2O2 (also known as NCM) 622 LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM) 811 ), lithium nickel cobalt aluminum oxide (such as LiNi) 0.85 Co 0.15 Al 0.05 At least one of O2 and its modified compounds. Examples of lithium phosphates with an olivine structure include, but are not limited to, lithium iron phosphate (such as LiFePO4), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium manganese iron phosphate, and lithium manganese iron phosphate and carbon composites.

[0089] In some embodiments, for a solid-state battery cell, the positive electrode active layer contains a solid electrolyte, and the solid electrolyte and the electrolyte in the solid electrolyte layer may be the same or different, for example, they may be the same sulfide electrolyte.

[0090] In some embodiments, the positive electrode active layer further comprises a conductive agent and a binder, and the mass ratio of the positive electrode active material, the solid electrolyte, the conductive agent, and the binder is (50–99):(0.1–50):(0.1–5):(0.1–5). The positive electrode active material layer formed according to the above mass ratio not only enables the positive electrode active layer of the positive electrode sheet to form a good ion-conducting network, but also exhibits good stability and is not easily detached.

[0091] In some embodiments, the conductive agent in the positive electrode active layer can be a conductive material commonly used in the art, including but not limited to at least one of graphite, carbon nanotubes, nanofibers, carbon black, and graphene. Specifically, it can be selected from at least one of SP, KS-6, acetylene black, branched Ketjen black ECP, SFG-6, vapor-grown carbon fiber VGCF, carbon nanotubes CNTs, and graphene and their composite conductive agents. The binder can be a binder commonly used in the art, selected from at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), ethylene-tetrafluoroethylene-propylene terpolymer, ethylene-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, hydrogenated nitrile rubber, styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA), carboxymethyl chitosan (CMCS), and fluorinated acrylate resins.

[0092] In some embodiments, the positive current collector may be a metal foil, a foamed metal, or a composite current collector. For example, as a metal foil, silver-treated aluminum or stainless steel, stainless steel, copper, aluminum, nickel, carbon electrodes, carbon, nickel, or titanium, etc., may be used. The foamed metal may be foamed nickel, foamed copper, foamed aluminum, foamed alloy, or foamed carbon, etc. The composite current collector may include a polymeric material base layer and a metal layer. The composite current collector can be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymeric material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0093] In some embodiments, the negative electrode may consist only of a negative current collector, meaning the corresponding battery cell is a metal battery cell without negative electrode active materials such as silicon carbide. Lithium metal material is deposited on the negative current collector during subsequent charge and discharge processes. Alternatively, the negative electrode may consist of a lithium metal sheet bonded to the negative current collector. Lithium metal offers advantages such as a low electrochemical potential (-3.04V vs SHE) and a high theoretical capacity (3861 mA hg). -1 This characteristic is that, when matched with sulfide electrolytes with high ionic conductivity, side reactions are more severe without a polyionic liquid layer. Therefore, this embodiment not only reduces the risk of increased interfacial resistance of the lithium metal solid electrolyte layer, but also alleviates lithium metal volume expansion and reduces the risk of lithium dendrite formation during repeated charge-discharge processes at the solid-solid contact interface.

[0094] For example, in this embodiment of the application, a polyionic liquid layer with a certain degree of flexibility is constructed in situ by thermal polymerization between the negative electrode lithium metal sheet and the solid electrolyte layer. The polyionic liquid has characteristics such as high thermal and electrochemical stability and excellent ionic conductivity. As an isolation layer between the solid electrolyte and lithium metal, it can reduce the risk of interfacial side reactions and poor contact. Furthermore, the polyionic liquids constructed in situ can form a cross-linked network through hydrogen bonds and have self-repairing ability, which can reduce lithium dendrite growth.

[0095] In this embodiment, the solid-state metal battery cell may include a battery casing and an electrode assembly encapsulated within the battery casing. The shape of the solid-state metal battery cell is not particularly limited; it can be cylindrical, square, or any other arbitrary shape. Figure 1 shows a square-structured solid-state metal battery cell 10.

[0096] In some embodiments, as shown in FIG2, the outer packaging of the solid metal battery cell 10 may include a housing 11 and a top cover assembly 12. The housing 11 may include a bottom plate and side plates connected to the bottom plate, the bottom plate and side plates enclosing a receiving cavity. The housing 11 has an opening communicating with the receiving cavity, and the top cover assembly 12 is used to cover the opening to close the receiving cavity. For the solid metal battery cell 10, the positive electrode sheet, solid electrolyte layer, polyionic liquid layer and negative electrode sheet contained in the battery cell of this application embodiment may be formed into an electrode assembly 13 by a lamination or winding process. The electrode assembly 13 is encapsulated in the receiving cavity.

[0097] Secondly, embodiments of this application provide a method for preparing a solid-state metal battery cell. The preparation method provided by embodiments of this application includes:

[0098] S01: Prepare a precursor solution, which includes a polymerizable ionic liquid monomer and a metal salt.

[0099] S02: Apply the precursor solution to the surface of the solid electrolyte layer away from the positive electrode, and then attach the surface of the solid electrolyte layer coated with the precursor solution to the negative electrode; or apply the precursor solution to the surface of the negative electrode, and then attach the surface of the negative electrode coated with the precursor solution to the surface of the solid electrolyte layer away from the positive electrode.

[0100] S03: The precursor solution between the negative electrode and the solid electrolyte layer is polymerized to form a polyionic liquid layer, thus obtaining a solid metal battery cell.

[0101] This application embodiment involves in-situ polymerization of a polyionic liquid layer containing polyionic liquid and metal salt between the negative electrode and the solid electrolyte layer. This polyionic liquid layer provides stability to both the solid electrolyte layer and the negative electrode, reducing the risk of side reactions. Simultaneously, the in-situ polymerized polyionic liquid layer allows for better interfacial contact between the solid electrolyte layer and the negative electrode. The in-situ constructed polyionic liquids can form a cross-linked network through hydrogen bonds and possess self-healing capabilities. Through the flexibility and self-healing ability of the polyionic liquid layer, the volume expansion of the negative electrode is mitigated, reducing the risk of dendrite growth. Therefore, the solid-state metal battery cell obtained by this preparation method can achieve high discharge specific capacity and cycle stability, exhibiting excellent charge-discharge performance.

[0102] In some embodiments, the step of preparing the precursor solution includes: mixing the ionic liquid monomer and the metal salt according to (

[0103] The monomers are mixed in a molar ratio of 8–1):1, and then an initiator comprising 1–5% of the ionic liquid monomer mass is added and mixed. The precursor solution prepared according to the above ratio can polymerize well to form a polyionic liquid layer. The ionic liquid monomers include acrylate ionic liquid monomers. Acrylate ionic liquid monomers can polymerize well to form stable and flexible acrylate polyionic liquid materials.

[0104] In some embodiments, the acrylate ionic liquid monomers include at least one selected from the following: 1-ethyl-3-acrylate imidazole bisfluorosulfonylimide salt, 1-ethyl-acrylate pyridine bis(trifluoromethanesulfonylimide) salt, 1-ethyl-acrylate pyridine bis(trifluoromethanesulfonylimide) salt, 1-ethyl-1-acrylate piperidine bis(trifluoromethanesulfonylimide) salt, 1-ethyl-1-acrylate pyrrolidine bis(trifluoromethanesulfonylimide) salt, and 1-ethyl-1-acrylate pyrrolidine bis(trifluoromethanesulfonylimide) salt. These monomers are widely available and readily obtained, and can be polymerized to form acrylate polyionic liquids.

[0105] In some embodiments, the initiator may be a commonly used azo initiator, such as azobisisobutyronitrile (AIBN).

[0106] In some embodiments, the above-mentioned polymerization reaction can be thermal in-situ polymerization, photopolymerization in-situ polymerization, or irradiation in-situ polymerization. For ease of operation, thermal in-situ polymerization is used. Specifically, the polymerization temperature is 60–80°C, for example, 60°C, 65°C, 70°C, 75°C, 80°C, etc., and the polymerization time under these conditions is 3–24 hours. Under the above temperature and time conditions, the ionic liquid monomer can be fully polymerized in situ. By adjusting the polymerization time, different degrees of polymerization can be achieved, thereby enabling the solid-state metal battery monomer to exhibit the desired electrochemical performance.

[0107] In some embodiments, the preparation method of the solid metal battery described above in this application includes: (1) stirring polymerizable acrylate ionic liquid monomers and lithium salts at a molar ratio of 8 to 1:1 at room temperature for 12-24 hours, then adding an initiator of 1-5% by mass of the ionic liquid monomer, and continuing to stir for 6-12 hours to obtain the precursor; (2) coating about 10-50 μL of the precursor solution between the negative electrode and the solid electrolyte layer (the precursor solution can be first coated on the surface of the solid electrolyte layer and then attached to the negative electrode; or the precursor solution can be coated on the surface of the negative electrode and then attached to the solid electrolyte layer); (3) heating at 60-80°C for 3-24 hours under an inert atmosphere to allow the precursor solution to undergo a polymerization reaction.

[0108] The embodiments of this application assemble the above-mentioned solid metal battery cells and test the cycle stability of the battery cells under low pressure (e.g., 5 MPa), and the results show that the effect is improved.

[0109] [Battery Device]

[0110] A third aspect of this application provides a battery device. The battery device of this application includes the solid-state metal battery cell provided in the first aspect of this application or the solid-state metal battery cell prepared by the preparation method provided in the second aspect. By employing the solid-state metal battery cell provided in this application, the battery device exhibits excellent cycle performance, specific capacity, and initial coulombic efficiency, enabling it to perform excellent charge and discharge cycles.

[0111] 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 battery cells connected in series, parallel, or mixed connections via a busbar.

[0112] In some embodiments, the battery device of this application may include any one of a solid metal battery cell, a battery module, or a battery pack.

[0113] A battery module is assembled from these solid metal battery cells, meaning it can contain multiple of these solid metal battery cells. The specific number can be adjusted according to the application and capacity of the battery module.

[0114] In some embodiments, FIG3 is a schematic diagram of a battery module 20 as an example. In the battery module 20, a plurality of solid metal battery cells 10 may be arranged sequentially along the length direction of the battery module 20. Of course, they can also be arranged in any other manner. Furthermore, the plurality of solid metal battery cells 10 can be fixed by fasteners.

[0115] Optionally, the battery module 20 may also include a housing with a receiving space in which a plurality of solid metal battery cells 10 are received.

[0116] A battery pack refers to an assembly of solid-state metal battery cells 10, as described above. It can contain multiple solid-state metal battery cells 10, which can be assembled into a battery module 20. The specific number of solid-state metal battery cells 10 or battery modules 20 in the battery pack can be adjusted according to the application and capacity of the battery pack.

[0117] As shown in the embodiment, Figures 4 and 5 are schematic diagrams of a battery pack 30 as an example. The battery pack 30 may include a battery compartment and multiple battery modules 20 disposed within the battery compartment. The battery compartment includes an upper compartment 31 and a lower compartment 32, the upper compartment 31 covering the lower compartment 32 and forming a closed space for accommodating the battery modules 20. The multiple battery modules 20 can be arranged in any manner within the battery compartment.

[0118] Electrical appliances

[0119] A fourth aspect of this application provides an electrical device. The electrical device of this application includes the solid-state metal battery cell provided in the first aspect of this application, the solid-state metal battery cell prepared by the preparation method provided in the second aspect, or the battery device provided in the third aspect of this application. The solid-state metal battery cell or battery device is used to store or provide electrical energy. Based on the use of the solid-state battery cell or battery device of this application, the electrical device of this application can operate more effectively.

[0120] Electrical devices can be, but are not limited to, mobile devices (such as mobile phones, portable devices, 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, electric vehicles, electric toys, power tools, etc.), electric trains, ships, satellites and spacecraft, energy storage systems, etc. The type of electrical device can be selected from individual battery cells, battery modules, or battery packs according to its usage requirements.

[0121] Figure 6 is a schematic diagram of an example electrical device. This device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc. To meet the device's requirements for high power and high energy density, a battery pack or battery module can be used.

[0122] Another example of an electrical device could be a mobile phone, tablet, or laptop. These devices typically require a slim and lightweight design and can use rechargeable batteries as their power source.

[0123] Example

[0124] The following describes embodiments of this application. 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 according to 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.

[0125] Example 1

[0126] The composition and preparation method of solid metal battery cells are as follows.

[0127] (1) Positive electrode plate

[0128] Fabrication of the positive electrode: The positive active material (core material NCM811, surface shell material LiNbO3): sulfide electrolyte (Li6PS5Cl): nitrile rubber (NBR): conductive carbon black are mixed in a mass ratio of 70:27.5:1.5:1. After adding toluene as solvent, a positive electrode slurry is obtained. The positive electrode slurry is coated on aluminum foil and dried in a vacuum at 100°C for 6 hours in an argon atmosphere. It is then cut into 10mm round pieces, which are the positive electrode sheets.

[0129] (2) Negative electrode plate

[0130] Preparation of negative electrode sheet: Lithium foil is attached to copper foil by rolling and cut into negative electrode sheet.

[0131] (3) Battery cell assembly

[0132] Preparation of sulfide electrolyte: Li6PS5Cl was prepared by ball milling followed by heat treatment in an argon atmosphere. Stoichiometric amounts of Li2S, P2S5, and LiCl were ball-milled together with ZrO2 balls in a ball mill jar at 200 rpm for 10 h. The resulting powder was annealed at 550 °C for 5 h to obtain the sulfide electrolyte.

[0133] Precursor solution preparation: Ionic liquid monomer (1-ethyl-3-acrylate imidazole trifluoromethanesulfonylimide salt) and lithium salt (lithium bis(trifluoromethanesulfonylimide) lithium) were stirred at room temperature in a molar ratio of 4:1 for 12 h. Then, 3% by mass of azobisisobutyronitrile was added and stirring was continued for 8 h to obtain the precursor solution.

[0134] 100 mg of Li6PS5Cl electrolyte powder was weighed and placed into a mold with a diameter of 10 mm. The mixture was pressed at 350 MPa for 1 min to obtain a solid electrolyte layer. The positive electrode sheet was placed on one side of the solid electrolyte layer and pressed at 350 MPa for 1 min. 30 μL of the precursor solution was added to the other side of the solid electrolyte layer, and then the negative electrode sheet was attached. The initially assembled battery cell was polymerized at 60 °C for 12 h in an argon-filled atmosphere to form a 30 μm thick polyionic liquid layer, thus obtaining a solid metal battery cell.

[0135] Examples 2-8

[0136] See Table 1 for the differences from Example 1.

[0137] Comparative Example 1

[0138] The difference from Example 1 is that there is no polyionic liquid layer, but everything else is the same as Example 1.

[0139] Performance testing

[0140] (1) Initial discharge capacity test: The assembled solid metal battery cell was charged to 4.3V at a current density of 0.1C, allowed to stand for 10 minutes, and then discharged to 2.6V at a current density of 0.1C to obtain the initial discharge capacity of the solid metal battery cell. The solid metal battery cell was tested at 25℃ and 5MPa pressure, where 1C = 185mA / g.

[0141] (2) Initial Coulombic Efficiency: The initial coulombic efficiency of a solid metal battery cell can be obtained by dividing the initial discharge capacity obtained by testing at 0.1C by the initial charge capacity.

[0142] (3) Cycle capacity retention test: The assembled solid-state metal battery cells were first subjected to constant current charge-discharge for 3 cycles at a current density of 0.1C to obtain the initial discharge capacity and initial coulombic efficiency. Then, a long-cycle test was conducted at a current density of 0.33C for 100 cycles to calculate the cycle capacity retention of the solid-state metal battery cells. The voltage test window for the solid-state metal battery cells was 2.6-4.3V vs. Li + / Li, solid metal battery cells were tested at 25℃ and 5MPa pressure, where 1C = 185mA / g.

[0143] The test results are shown in Table 2.

[0144] Table 1

[0145] Table 2

[0146] The data in the table above shows that, compared to Comparative Example 1, the solid-state battery cells in Examples 1-8 have a polyionic liquid layer between the solid electrolyte layer and the negative electrode, which significantly improves the specific capacity, initial coulombic efficiency, and capacity retention of the battery cells. By appropriately adjusting the composition and proportion of the cells in the polyionic liquid layer, the battery performance can be further improved. Specifically, in Examples 7 and 8, adding an appropriate amount of non-polymerized ionic liquid to the polyionic liquid layer containing polyionic liquid and lithium salt further improves the charge-discharge performance of the battery.

[0147] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A solid-state metal battery cell, characterized in that, It includes a positive electrode, a negative electrode, and a solid electrolyte layer located between the positive electrode and the negative electrode; wherein, a polyionic liquid layer is disposed between the solid electrolyte layer and the negative electrode, and the material of the polyionic liquid layer includes a polyionic liquid and a metal salt.

2. The solid-state metal battery cell as described in claim 1, characterized in that, The polyionic liquid includes acrylate-based polyionic liquids.

3. The solid-state metal battery cell as described in claim 2, characterized in that, The repeating unit of the acrylate polyionic liquid includes at least one of the following: ethyl 3-acrylate imidazole bisfluorosulfonyl imide salt, ethyl acrylate pyridine bis(trifluoromethanesulfonyl imide salt, ethyl acrylate pyridine bis(trifluoromethanesulfonyl imide salt, ethyl acrylate pyrrole bis(trifluoromethanesulfonyl imide salt, ethyl acrylate pyrrole bis(trifluoromethanesulfonyl imide salt, ethyl 1-acrylate piperidine bis(trifluoromethanesulfonyl imide salt, ethyl 1-acrylate piperidine bis(trifluoromethanesulfonyl imide salt, ethyl 1-acrylate pyrrole bis(trifluoromethanesulfonyl imide salt, ethyl 1-acrylate pyrrole bis(trifluoromethanesulfonyl imide salt).

4. The solid-state metal battery cell according to any one of claims 1-3, characterized in that, The molar ratio of the monomer raw material to the metal salt in the polyionic liquid is (8-1):

1.

5. The solid-state metal battery cell according to any one of claims 1-4, characterized in that, The material of the polyionic liquid layer also includes non-polymerized ionic liquids.

6. The solid-state metal battery cell as described in claim 5, characterized in that, The non-polymerized ionic liquid includes at least one of 1-methyl-1-propylpyrrolidine onium bisfluorosulfonylimide salt, 1-methyl-1-propylpyrrolidine bis(trifluoromethanesulfonylimide) salt, lithium bis(fluorosulfonylimide) salt tetraethylene glycol ester, lithium bis(trifluoromethanesulfonylimide) salt tetraethylene glycol ester, 1-ethyl-3-methylimidazolium bis(fluorosulfonylimide) salt, and 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonylimide) salt. And / or, the molar ratio of the monomer raw material in the polyionic liquid to the non-polymerized ionic liquid is (5-8):

1.

7. The solid-state metal battery cell according to any one of claims 1-6, characterized in that, The thickness of the polyionic liquid layer is 10–50 μm.

8. The solid-state metal battery cell according to any one of claims 1-7, characterized in that, The solid metal battery cell includes a solid lithium metal battery cell, and the metal salt includes a lithium salt.

9. The solid-state metal battery cell as described in claim 8, characterized in that, The lithium salt includes at least one of lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium hexafluorophosphate, lithium perchlorate, and lithium tetrafluoroborate.

10. The solid-state metal battery cell as described in claim 8 or 9, characterized in that, The negative electrode sheet includes a lithium metal sheet.

11. The battery cell according to any one of claims 1-10, characterized in that, The solid electrolyte layer includes at least one of a halide electrolyte and a sulfide electrolyte.

12. A method for preparing a solid-state metal battery cell, characterized in that, include: A precursor solution is prepared, wherein the precursor solution comprises a polymerizable ionic liquid monomer and a metal salt; The precursor solution is applied to the surface of the solid electrolyte layer away from the positive electrode, and then the surface of the solid electrolyte layer coated with the precursor solution is bonded to the negative electrode; or the precursor solution is applied to the surface of the negative electrode, and then the surface of the negative electrode coated with the precursor solution is bonded to the surface of the solid electrolyte layer away from the positive electrode. The precursor solution between the bonded negative electrode and the solid electrolyte layer is polymerized to form a polyionic liquid layer, thus obtaining a solid metal battery cell.

13. The preparation method according to claim 12, characterized in that, The step of preparing the precursor solution includes: mixing the ionic liquid monomer and the metal salt in a molar ratio of (8-1):1, and then adding an initiator accounting for 1-5% of the mass of the ionic liquid monomer.

14. The preparation method according to claim 12 or 13, characterized in that, The ionic liquid monomers include acrylate-based ionic liquid monomers.

15. The preparation method according to claim 14, characterized in that, The acrylate ionic liquid monomers include at least one of the following: 1-ethyl-3-acrylate imidazole bisfluorosulfonyl imide salt, 1-ethyl-acrylate pyridine bis(trifluoromethanesulfonyl) imide salt, 1-ethyl-acrylate pyridine bis(trifluoromethanesulfonyl) imide salt, 1-ethyl-1-acrylate piperidine bis(trifluoromethanesulfonyl) imide salt, 1-ethyl-1-acrylate pyrrolidine bis(trifluoromethanesulfonyl) imide salt, and 1-ethyl-1-acrylate pyrrolidine bis(trifluoromethanesulfonyl) imide salt.

16. The preparation method according to any one of claims 12-15, characterized in that, The polymerization reaction is carried out at a temperature of 60–80°C; and / or the polymerization reaction is carried out for a time of 3–24 hours.

17. A battery device, characterized in that, Includes solid metal battery cells as described in any one of claims 1-11 or solid metal battery cells prepared by the preparation method described in any one of claims 12-16.

18. An electrical appliance, characterized in that, Includes a solid metal battery cell as described in any one of claims 1-11, a solid metal battery cell prepared by the preparation method described in any one of claims 12-16, or a battery device as described in claim 17, wherein the solid metal battery cell or the battery device is used to store or provide electrical energy.

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