Negative electrode of solid-state battery cell, and solid-state battery cell, preparation method therefor and use thereof

Abstract

The present application relates to the technical field of batteries, and specifically relates to a negative electrode of a solid-state battery cell, and a solid-state battery cell, a preparation method therefor and the use thereof. The solid-state battery cell comprises a positive electrode, a negative electrode, and a solid-state electrolyte layer arranged between the positive electrode and the negative electrode, wherein the negative electrode comprises a negative electrode current collector and a negative electrode layer stacked on at least one surface of the negative electrode current collector, and the negative electrode layer comprises metal wires and carbon materials. The metal wires provide abundant and uniform lithiophilic sites, which enable the rapid transfer of lithium atoms into a bulk phase of lithium metal, thereby realizing uniform deposition of the lithium metal, inhibiting dendrite growth, reducing the accumulation of by-products such as dead lithium, and improving the cycling stability of batteries. The carbon materials have a relatively low volume expansion effect and can induce interfacial reactions, thereby forming excellent ion and electron transport channels, reducing interfacial resistance, and prompting the uniform deposition of the lithium metal. The metal wires also have a self-supporting property and mechanical strength, which can alleviate volume strain during lithium deposition, thereby enhancing the cycling safety of batteries.

Description

Anode of solid-state battery cell, solid-state battery cell and its preparation method and application

[0001] This application claims priority to Chinese Patent Application No. 202411790044.9, filed on December 6, 2024, entitled “Negative Electrode of Solid-State Battery Cell, Solid-State Battery Cell and Preparation Method Thereof and Application”, 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 negative electrode of a solid-state battery cell, a solid-state battery cell, its preparation method and application. Background Technology

[0003] Solid-state batteries, with their advantages of high energy density, high power, and high safety, possess enormous potential for application and are currently one of the most widely used energy storage systems. Compared to liquid lithium-ion batteries, solid-state battery systems using metallic lithium as the negative electrode offer higher energy density and safety. However, the solid-solid interface kinetics in solid-state lithium batteries are poor, and uneven lithium-ion deposition on the negative electrode side leads to unavoidable dendrite growth and interfacial side reactions. With increasing cycle count, the continuously growing dendrites can cause short circuits and battery failure. Furthermore, the lithium deposition process causes volume expansion at the cell level, leading to solid-solid interface degradation. Significant volume expansion during charge and discharge also results in irreversible capacity decay, significantly hindering the practical application of solid-state lithium batteries.

[0004] Application content

[0005] One of the objectives of this application is to provide a negative electrode for a solid-state battery cell, a solid-state battery cell, a method for preparing the same, and its application, in order to solve the technical problem of uneven lithium ion deposition on the negative electrode in existing solid-state batteries, which leads to lithium dendrite growth and cell volume expansion.

[0006] The technical solution adopted in the embodiments of this application is:

[0007] In a first aspect, this application provides a solid-state battery cell, including a positive electrode and a negative electrode, and a solid electrolyte layer disposed between the positive electrode and the negative electrode. The negative electrode includes a negative electrode current collector and a negative electrode layer stacked on at least one surface of the negative electrode current collector. The negative electrode layer includes metal wires and carbon materials.

[0008] In some embodiments, the mass ratio of the metal wire to the carbon material in the negative electrode layer is 1:(1 to 10).

[0009] In some embodiments, the metal wires and the carbon material in the negative electrode layer form a three-dimensional conductive network structure.

[0010] In some embodiments, the morphology of the carbon material includes particulate form.

[0011] In some embodiments, the metal wire has at least one of the following features (1) to (5):

[0012] (1) The metal material in the metal wire includes at least one of Ag, Zn, Al, Sn, and Ni;

[0013] (2) The average diameter of the metal wire is 50 nm to 100 nm;

[0014] (3) The average length of the metal wire is 500 nm to 3 μm;

[0015] (4) The aspect ratio of the metal wire is 10 to 600;

[0016] (5) The specific surface area of ​​the metal wire is 8m². 2 / g~15m 2 / g.

[0017] In some embodiments, the carbon material has at least one of the following characteristics (1) to (5):

[0018] (1) The carbon material includes at least one of hard carbon, carbon black, soft carbon, graphene, carbon nanotubes, natural graphite, and artificial graphite;

[0019] (2) The carbon material is in particulate form, and the particle size Dv50 of a single particle is 20nm to 2μm;

[0020] (3) The specific surface area of ​​the carbon material is 30m². 2 / g~500m 2 / g;

[0021] (4) The compaction density of the carbon material is 0.7 g / cm³. 3 ~0.9g / cm 3 ;

[0022] (5) The carbon material has mesoporous and microporous structures.

[0023] In some embodiments, the pore size of the mesopores is 2nm to 50nm, and the pore size of the micropores is no higher than 2nm.

[0024] In some embodiments, the carbon material has a mesopore volume percentage of 5% to 30% and a micropore volume percentage of no more than 60%.

[0025] In some embodiments, the porosity of the carbon material is 30% to 60%.

[0026] In some embodiments, the carbon material includes carbon black, which has at least one of the following characteristics (1) to (3):

[0027] (1) The particle size Dv50 of the individual carbon black particles is 20nm to 100nm;

[0028] (2) The specific surface area of ​​the carbon black is 50 m². 2 / g~500m 2 / g;

[0029] (3) The compacted density of the carbon black is 0.7 g / cm³. 3 ~0.9g / cm 3 .

[0030] In some embodiments, the carbon material includes hard carbon, which has at least one of the following characteristics (1) to (4):

[0031] (1) The particle size Dv50 of the individual hard carbon particles is 50 nm to 2 μm;

[0032] (2) The specific surface area of ​​the hard carbon is 50 m². 2 / g~500m 2 / g;

[0033] (3) The compaction density of the hard carbon is 0.75 g / cm³. 3 ~0.9g / cm 3 ;

[0034] (4) In the hard carbon, the volume percentage of mesopores is 5% to 30%, and the volume percentage of micropores is not higher than 60%.

[0035] In some embodiments, the negative electrode layer also includes a binder.

[0036] In some embodiments, the adhesive includes at least one of polyvinylidene fluoride, nitrile rubber, polytetrafluoroethylene, and sodium carboxymethyl cellulose.

[0037] In some embodiments, the binder in the negative electrode layer has a mass percentage content of 1% to 10%.

[0038] In some embodiments, the thickness of the negative electrode layer is 10 μm to 20 μm.

[0039] Secondly, this application provides a method for preparing a solid-state battery cell, comprising the following steps:

[0040] After the metal wire is combined with carbon material, binder and solvent to form a negative electrode slurry, a negative electrode layer is formed on at least one surface of the negative electrode current collector to obtain a negative electrode.

[0041] The negative electrode is assembled with the positive electrode and a solid electrolyte to obtain a solid-state battery cell.

[0042] In some embodiments, the metal wire includes at least one of silver wire, zinc wire, aluminum wire, nickel wire, and tin wire.

[0043] In some embodiments, the carbon material includes at least one of hard carbon, carbon black, soft carbon, graphene, carbon nanotubes, natural graphite, and artificial graphite.

[0044] In some embodiments, the adhesive includes at least one of polyvinylidene fluoride, nitrile rubber, polytetrafluoroethylene, and sodium carboxymethyl cellulose.

[0045] In some embodiments, the mass ratio of the metal wire to the carbon material is 1:(1-10).

[0046] In some embodiments, the total mass of the metal wire and the carbon material is in the mass ratio of the binder to (90-99):(1-10).

[0047] In some embodiments, the thickness of the negative electrode layer on the surface of the negative electrode current collector is 10 μm to 20 μm.

[0048] In some embodiments, the metal wire comprises a silver wire, and the preparation of the silver wire includes the steps of:

[0049] Silver source dispersion was prepared by dissolving silver salt and growth guide agent in polyol solvent;

[0050] After preparing the crystal form inducing agent solution, it was added to the silver source dispersion and heated to obtain silver wire.

[0051] In some embodiments, the polyol solvent includes at least one selected from ethylene glycol, propylene glycol, glycerol, 1,2-propanediol, 1,4-butanediol, 1,6-hexanediol, and neopentyl glycol.

[0052] In some embodiments, the growth-directing agent includes at least one of polyvinylpyrrolidone and polyether.

[0053] In some embodiments, the silver salt includes at least one of silver nitrate, silver sulfate, and silver halide.

[0054] In some embodiments, the crystal form inducing agent solution includes at least one of copper salt and zinc salt.

[0055] In some embodiments, the solvent in the crystal form inducing agent solution includes at least one of ethylene glycol, propylene glycol, glycerol, 1,2-propanediol, 1,4-butanediol, 1,6-hexanediol, and neopentyl glycol.

[0056] In some embodiments, the temperature conditions for the heating reaction are 120°C to 140°C, and the reaction time is 1 hour to 2 hours.

[0057] Thirdly, this application provides a battery device, including the above-described battery cell or a solid-state battery cell prepared by the above-described preparation method.

[0058] Fourthly, this application provides an electrical device comprising the aforementioned solid-state battery cell, or a solid-state battery cell prepared by the aforementioned preparation method, or the aforementioned battery device.

[0059] Fifthly, this application provides an energy storage device, including the above-described solid-state battery cell, or a solid-state battery cell prepared by the above-described preparation method, or the above-described battery device.

[0060] In a sixth aspect, this application provides a negative electrode for a solid-state battery cell, the negative electrode comprising a negative electrode current collector and a negative electrode layer stacked on at least one surface of the negative electrode current collector, the negative electrode layer comprising metal wires and carbon material.

[0061] The solid-state battery cell provided in the first aspect of this application features a uniformly distributed metal wire in the negative electrode layer, providing abundant and uniform lithiophilic sites for continuous adsorption of lithium ions within the negative electrode layer. Simultaneously, the wire acts as a diffusion channel to rapidly transfer lithium atoms into the lithium metal bulk phase, achieving uniform lithium metal deposition. This suppresses dendrite growth, reduces the accumulation of byproducts such as dead lithium, and improves the cycle stability of the solid-state battery cell. The carbon material in the negative electrode layer possesses high electronic / ionic conductivity. During lithiation, the carbon material exhibits low volume expansion and induces interfacial reactions, forming excellent ion and electron transport channels. This promotes efficient lithium ion transport at the interface between the negative electrode and the solid electrolyte, significantly reducing interfacial resistance and facilitating uniform lithium metal deposition. Furthermore, the metal wire possesses self-supporting properties and a certain mechanical strength, mitigating volume strain in the carbon material during lithium deposition. This contributes to improving the overall structural stability, strength, and integrity of the negative electrode layer, reducing volume expansion during cycling, suppressing structural damage to the solid-state battery cell during cycling, and enhancing the safety of the solid-state battery cell during cycling.

[0062] The second aspect of this application discloses a method for preparing a solid-state battery cell. After preparing metal wires, a negative electrode slurry is formed with carbon materials, a binder, and a solvent. A negative electrode layer is then formed on the surface of the negative electrode current collector, and finally assembled with a positive electrode and a solid electrolyte to obtain a solid-state battery cell. The preparation process is simple and suitable for large-scale industrial production and application. The metal wires and carbon materials in the negative electrode layer form a uniformly distributed three-dimensional conductive network structure, which is beneficial for improving the uniformity of ion and electron transport in the negative electrode layer, thereby improving the uniformity of lithium-ion deposition. Furthermore, the metal wires provide abundant and uniform lithiophilic sites, continuously adsorbing lithium ions within the negative electrode layer. Simultaneously, they can act as diffusion channels to rapidly transfer lithium atoms into the lithium metal bulk phase, achieving uniform lithium metal deposition, suppressing dendrite growth, reducing the accumulation of byproducts such as dead lithium, and improving the cycle stability of the solid-state battery cell. In addition, the carbon materials in the negative electrode layer have high electronic / ionic conductivity. During lithiation, the carbon materials exhibit a low volume expansion effect and induce interfacial reactions, which can reduce interfacial resistance and promote uniform lithium metal deposition. Furthermore, the metal wires also possess self-supporting properties and a certain degree of mechanical strength, which can alleviate the volumetric strain of carbon materials during lithium deposition, thereby improving the overall structural stability of the negative electrode layer and enhancing the safety of solid-state battery cells during cycling.

[0063] The battery device provided in the third aspect of this application is based on the solid-state battery cell of this application. Therefore, the battery device of this application has a good cycle life under the premise of high energy density.

[0064] The electrical device provided in the fourth aspect of this application is based on the solid-state battery cell or battery device of this application, and therefore the electrical device of this application can operate safely and for a long time.

[0065] Fifthly, since the energy storage device of this application contains the solid-state battery cells or battery devices described above, the energy storage device has high energy density, good cycle performance, and long service life.

[0066] In the sixth aspect of this application, the negative electrode of a solid-state battery cell includes metal wires and carbon materials in the negative electrode layer on the surface of the negative electrode current collector. While enhancing ionic and electronic conductivity, it can not only reduce the loss of effective contact area caused by volume changes, but also make electrons uniformly distributed and thus optimize the deposition behavior of lithium. It can effectively induce uniform deposition of lithium metal and improve the safety of solid-state battery cells during cycling. Attached Figure Description

[0067] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or exemplary technologies 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.

[0068] Figure 1 is a schematic diagram of a solid-state battery cell according to an embodiment of this application;

[0069] Figure 2 is a schematic diagram of the metal wires and carbon materials in the negative electrode layer of a solid-state battery cell according to an embodiment of this application;

[0070] Figure 3 is an exploded view of the solid-state battery cell shown in Figure 1;

[0071] Figure 4 is a schematic diagram of one embodiment of the battery module of this application;

[0072] Figure 5 is a schematic diagram of one embodiment of the battery pack of this application;

[0073] Figure 6 is an exploded view of the battery pack shown in Figure 5.

[0074] Figure 7 is a schematic diagram of one embodiment of an electrical device that uses a secondary battery as a power source according to an embodiment of this application;

[0075] The reference numerals in the detailed embodiments are as follows: 10-Solid-state battery cell; 11-Housing casing; 12-Top cover assembly; 13-Electrode assembly; 20-Battery module; 30-Battery pack; 31-Upper housing; 32-Lower housing. Detailed Implementation

[0076] 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.

[0077] 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.

[0078] 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.

[0079] 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.

[0080] 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.

[0081] 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).

[0082] 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.

[0083] 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.

[0084] Currently, from a market perspective, solid-state batteries, due to their advantages of high energy density, power, and high safety, possess enormous potential application prospects and are one of the most widely used energy storage systems. Compared to liquid lithium-ion batteries, solid-state battery systems using metallic lithium as the negative electrode offer higher energy density and safety. However, the solid-solid interface kinetics in solid-state lithium batteries are poor, and uneven lithium-ion deposition on the negative electrode side causes unavoidable dendrite growth and interfacial side reactions. With increasing cycle count, the continuously growing dendrites can lead to short circuits and battery failure. Furthermore, the lithium deposition process causes volume expansion at the cell level, resulting in solid-solid interface degradation. Significant volume expansion during charge and discharge also leads to irreversible capacity decay, significantly hindering the practical application of solid-state lithium batteries.

[0085] Experimental studies revealed that lithium deposition on the negative electrode side is often influenced by the negative electrode layer on the surface of the negative electrode current collector. If the negative electrode layer has a poor effect on inducing lithium ion deposition, it can lead to uneven local lithium deposition, resulting in rapid growth of lithium dendrites and battery short circuits and failures. Simultaneously, uneven lithium deposition can also cause solid-solid interface degradation, leading to volume expansion at the cell level and ultimately, rapid battery failure.

[0086] Studies have found that silver can effectively induce uniform lithium deposition, but the uniform dispersion of silver in the deposition-inducing layer is difficult, which limits its ability to induce uniform lithium deposition. In some embodiments, a second metal, such as copper, nickel, titanium, tungsten, iron, or combinations thereof, which does not react with lithium, is introduced into the anode material. The second metal has a non-spherical structure, and the first metal (Ag) is disposed on at least one surface of the second metal. An example of the preparation method is as follows: Cu nanowires are mixed and stirred with AgNO3 solution, centrifuged, and dried to obtain a Cu / Ag structure; then mixed with carbon materials to form a slurry, coated, and dried. While the binding of silver by the second metal can improve the uniformity of silver dispersion and inhibit silver migration and diffusion to some extent, the introduction of the second metal, such as copper, nickel, titanium, tungsten, iron, or combinations thereof, does not react with lithium, and therefore the effect on improving the uniformity of lithium deposition is not significant.

[0087] Based on the above considerations, in order to solve the technical problem of uneven lithium-ion deposition at the negative electrode in solid-state batteries, which leads to lithium dendrite growth and cell volume expansion, this application has developed a solid-state battery cell after in-depth research. This cell features a negative electrode layer comprising metal wires and carbon materials on the surface of the negative electrode current collector. This ensures both uniform distribution of the metal and carbon materials and excellent ionic and electronic conductivity, effectively improving the uniformity of lithium deposition.

[0088] For ease of understanding, this application is specifically described through the following embodiments. It should be understood that the following embodiments are only used to further illustrate the solution of this application and are not intended to limit the scope of this application.

[0089] Solid-state battery cell 10

[0090] In a first aspect, embodiments of this application provide a solid-state battery cell 10. In some embodiments, as shown in FIG1, the solid-state battery cell 10 of this application includes a positive electrode and a negative electrode, and a solid electrolyte layer disposed between the positive electrode and the negative electrode. The negative electrode includes a negative electrode current collector and a negative electrode layer stacked on at least one surface of the negative electrode current collector. The negative electrode layer includes metal wires and carbon materials.

[0091] In the solid-state battery cell 10 of this application embodiment, the negative electrode is the electrode with a lower potential in the battery, typically the electrode where oxidation (i.e., losing electrons) occurs in the internal electrochemical reaction of the battery. The positive electrode is the electrode with a higher potential in the battery, typically the electrode where reduction (i.e., accepting electrons) occurs in the internal electrochemical reaction of the battery. The solid electrolyte layer refers to the electrolyte layer in which the electrolyte exists in a solid form, playing the role of transporting ions and blocking electrons. Compared with liquid electrolytes, solid electrolytes have the characteristics of being leak-proof, non-deteriorating, and easy to transport. Metal wire refers to a one-dimensional metal structure, whose diameter (or lateral dimension) is typically between tens of nanometers and hundreds of nanometers, with an aspect ratio greater than 10.

[0092] The solid-state battery cell 10 provided in this application embodiment has a negative electrode layer disposed on at least one surface of the negative electrode current collector. The negative electrode layer includes metal wires and carbon materials. On the one hand, the metal wires can be uniformly distributed in the negative electrode layer. Under the premise of uniform distribution, longer metal wires can more effectively form a three-dimensional conductive network. This network structure can achieve a balance of high conductivity, reduce resistance, and improve conductivity. In contrast, metal particles mainly rely on the close contact and number density between particles to achieve conductivity, and their conductivity is affected by the contact resistance between particles and the uniformity of distribution. Therefore, metal wires and carbon materials can form a uniformly distributed three-dimensional conductive network structure, which is beneficial to improving the uniformity of ion and electron transport in the negative electrode layer, thereby improving the uniformity of lithium-ion deposition. On the other hand, the uniformly distributed metal wires in the negative electrode layer provide abundant and uniform lithiophilic sites. As lithium metal is deposited, lithium metal combines with the metal wires, and the interface between lithium metal and metal wires maintains conformal contact, forming abundant lithiophilic nuclei. Lithium ions are continuously adsorbed inside the negative electrode layer, and it can also act as a diffusion channel to rapidly transfer lithium atoms into the lithium metal bulk phase, achieving uniform lithium metal deposition. Without sacrificing energy density, uniform nucleation sites are formed on the surface to suppress dendrite growth, reduce the accumulation of byproducts such as dead lithium, and improve the cycle stability of the solid-state battery cell 10. Furthermore, the carbon material in the anode layer possesses high electronic / ionic conductivity and exhibits low volume expansion during lithiation. The lithium metal remaining on the carbon material surface after lithiation can also induce interfacial reactions, forming excellent ion and electron transport channels. This promotes efficient lithium-ion transport at the interface between the anode and the solid electrolyte, significantly reducing interfacial resistance and facilitating uniform lithium metal deposition. Simultaneously, the metal wires possess self-supporting properties and a certain mechanical strength, which can alleviate the volume strain of the carbon material during lithium deposition, thus improving the overall structural stability, strength, and integrity of the anode layer, reducing volume expansion during cycling, and suppressing structural damage to the solid-state battery cell 10 during cycling. The embodiments of this application include a negative electrode layer of metal wire and carbon material. While enhancing ionic and electronic conductivity, the negative electrode layer can not only reduce the loss of effective contact area caused by volume change, but also make electrons uniformly distributed and thus optimize the lithium deposition behavior. It can effectively induce uniform lithium metal deposition and improve the safety of solid-state battery cell 10 during cycle.

[0093] In some embodiments, the mass ratio of metal wire to carbon material in the negative electrode layer is 1:(1-10). In this case, the ratio of metal wire to carbon material sufficiently ensures the structural stability of both the metal wire and carbon material, improves the overall structural stability, strength, and integrity of the negative electrode layer, reduces the volume expansion of the negative electrode layer during cycling, and suppresses structural damage to the solid-state battery cell 10 during cycling. Furthermore, through the bilayer interaction between the carbon material and metal nanoparticles, it guides the uniform transport of lithium ions within the intermediate layer, improves the uniformity of lithium ion transport and deposition, induces uniform deposition of lithium metal on the negative electrode side, suppresses dendrite formation, and improves the electrochemical performance of the solid-state battery, such as coulombic efficiency, cycle stability, and safety. Exemplarily, the mass ratio of metal wire to carbon material can be any typical but non-limiting point value or a range between any two points, such as 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, etc.

[0094] In some embodiments, the metal material in the metal wire includes at least one of Ag, Zn, Al, Sn, and Ni. In this case, these metal materials all possess high electrical conductivity, can form alloys with lithium metal, and provide abundant and uniform lithiophilic sites, thus improving the uniform deposition of lithium metal. The metal wire formed by these metal materials has a one-dimensional structure with an excellent aspect ratio, which can improve the overall structural strength of the negative electrode layer while constructing a good electron-ion pathway. Furthermore, while enhancing electronic conductivity, the metal wire can also effectively induce the uniform deposition of lithium metal.

[0095] In some embodiments, the average diameter of the metal wire is 50 nm to 100 nm. For example, the average diameter of the metal wire can be any typical but non-limiting point value or a range between any two point values, such as 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm.

[0096] In some embodiments, the average length of the metal wire is 500 nm to 3 μm. For example, the average length of the metal wire can be any typical but non-limiting point value or an interval between any two point values, such as 500 nm, 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm.

[0097] In some embodiments, the aspect ratio of the metal wire is 10 to 600. For example, the aspect ratio of the metal wire can be any typical but non-limiting point value or a range between any two point values, such as 10, 20, 50, 100, 150, 200, 250, 300, 350, 400, 450, 500, 550, 600.

[0098] In the above embodiments, the metal wire has a small diameter and high length, resulting in a large aspect ratio. This not only improves the dispersion uniformity of the metal wire and carbon material, creating a good electron-ion pathway, but also enhances the uniformity of lithium metal deposition. The metal wire possesses self-supporting properties and a certain mechanical strength, which can also alleviate the volumetric strain of the carbon material during lithium deposition, improve the overall structural strength of the anode layer, enhance the overall structural strength and integrity of the carbon layer, and suppress structural damage to the anode layer during cyclic expansion.

[0099] In some implementations, the specific surface area of ​​the metal wire is 8m². 2 / g~15m 2 / g. For example, the specific surface area of ​​the metal wire can be 8m². 2 / g、9m 2 / g, 10m 2 / g、11m 2 / g、12m 2 / g、13m 2 / g、14m 2 / g, 15m 2 / g is a typical but not restrictive arbitrary point value or an interval between any two point values. In this case, the metal line has a high specific surface area, providing abundant nucleation sites for lithium metal deposition, thereby improving the uniformity of lithium metal deposition.

[0100] In some implementations, the carbon material in the negative electrode layer can be granular, such as hard carbon or carbon black, or one-dimensional linear, such as carbon nanotubes or carbon fibers, or two-dimensional sheet structures such as graphene. Carbon materials of different morphologies can form a unique conductive three-dimensional network structure with the metal wires, improving the uniformity of lithium metal deposition and reducing the risk of lithium dendrite growth.

[0101] In some embodiments, the morphology of the carbon material includes particulate form. Particulate carbon materials have a lower volume expansion effect during lithiation and better mutual filling effect with metal wires, reducing porosity between negative electrode layers and improving the uniformity of negative electrode layers, thereby improving the uniformity of lithium metal deposition.

[0102] In some embodiments, the carbon material includes at least one of hard carbon, carbon black, soft carbon, graphene, carbon nanotubes, natural graphite, and artificial graphite. In this case, these carbon materials not only possess high electronic / ionic conductivity, but also exhibit low volume expansion during lithiation, with negligible volume expansion after lithium intercalation. Particulate carbon materials, in particular, provide better inter-filling with the metal wires, reducing porosity between the negative electrode layers and improving the uniformity of the negative electrode layer, thereby enhancing the uniformity of lithium metal deposition.

[0103] In some embodiments, the carbon material is in particulate form, with a particle size Dv50 of 20 nm to 2 μm for each individual particle. Exemplarily, the carbon material is in particulate form, and the particle size Dv50 of each individual particle can be any typical but non-limiting point value or a range between any two points, such as 20 nm, 50 nm, 100 nm, 200 nm, 500 nm, 800 nm, 1000 nm, 1.2 μm, 1.5 μm, 1.8 μm, or 2 μm. In this case, the carbon material particles have better dispersion performance, resulting in smaller gaps between particles after being formed into the negative electrode layer.

[0104] In some embodiments, the specific surface area of ​​the carbon material is 30 m². 2 / g~500m 2 / g. For example, the specific surface area of ​​a carbon material can be 30m². 2 / g, 50m 2 / g, 100m 2 / g、200m 2 / g、300m 2 / g、400m 2 / g、500m 2 / g is a typical but not limiting arbitrary point value or an interval between any two point values. In this case, carbon materials have a high specific surface area, good dispersibility and stability, and high electronic / ionic conductivity.

[0105] In some embodiments, the compaction density of the carbon material is 0.7 g / cm³. 3 ~0.9g / cm 3 For example, the compaction density of carbon materials can be 0.7 g / cm³. 3 0.8g / cm 3 0.9g / cm 3 Typical but not restrictive point values ​​or intervals between any two point values ​​are considered. At this compaction density, the negative electrode layer exhibits good compactness.

[0106] In some embodiments, the carbon material possesses mesoporous and microporous structures. In this case, the mesoporous and microporous structures in the carbon material help suppress lithium absorption during lithiation, forming excellent ion and electron transport channels. This promotes efficient lithium-ion transport at the interface between the negative electrode and the solid electrolyte, significantly reduces interfacial resistance, and facilitates uniform lithium metal deposition.

[0107] In some embodiments, the pore size of mesopores is 2 nm to 50 nm, and the pore size of micropores is no larger than 2 nm. For example, the pore size of mesopores can be any typical but non-limiting value, such as 2 nm, 10 nm, 20 nm, 30 nm, 40 nm, or 50 nm, or a range between any two values; the pore size of micropores can be any typical but non-limiting value, such as 2 nm, 1 nm, or 0.5 nm, or a range between any two values. In this case, mesopores can improve battery performance by improving interfacial contact, mitigating volume changes, enhancing ion conduction, and improving thermal management; while micropores can improve battery performance and capacity by increasing capacitance and forming a stable layered structure.

[0108] In some embodiments, the volume percentage of mesopores in the carbon material is 5% to 30%, and the volume percentage of micropores is no more than 60%. In this case, through reasonable pore design, the surface and interface structure of the carbon material can be improved, the ion diffusion rate of the carbon material can be enhanced, thereby improving the dynamic behavior of the battery cell.

[0109] In some implementations, the porosity of the carbon material is 30%–60%. In this case, the carbon material contributes to better electrochemical performance of the battery. The porosity of the carbon material and the ratio of micropores to mesopores affect the lithium uptake of the carbon layer during charge-discharge cycles, thereby affecting the cycle stability of the battery cell.

[0110] In some embodiments, the carbon material includes carbon black, which has at least one of the following characteristics (1) to (3):

[0111] (1) The particle size Dv50 of a single carbon black particle is 20nm to 100nm;

[0112] (2) The specific surface area of ​​carbon black is 50m². 2 / g~500m 2 / g;

[0113] (3) The compacted density of carbon black is 0.7 g / cm³. 3 ~0.9g / cm 3 .

[0114] In the embodiments described above, carbon black possesses a suitable particle size, high specific surface area and compaction density, and good electrical conductivity. When added to the negative electrode of a solid-state battery, it can effectively improve the conductivity of the negative electrode, thereby reducing the battery's internal resistance and enhancing its power density and cycle stability. Furthermore, carbon black in the negative electrode layer of a solid-state battery can increase the tensile strength and toughness of the negative electrode layer, thereby improving the battery's mechanical stability, promoting ion transport at the interface, and enhancing the uniformity of lithium metal deposition.

[0115] In some embodiments, the carbon material includes hard carbon, which has at least one of the following characteristics (1) to (4):

[0116] (1) The particle size Dv50 of a single hard carbon particle is 50 nm to 2 μm;

[0117] (2) The specific surface area of ​​hard carbon is 50m². 2 / g~500m 2 / g;

[0118] (3) The compaction density of hard carbon is 0.75 g / cm³. 3 ~0.9g / cm 3 ;

[0119] (4) In hard carbon, the volume percentage of mesopores is 5% to 30%, and the volume percentage of micropores is no more than 60%.

[0120] In the embodiments described above, hard carbon possesses a unique microstructure, providing numerous active sites for lithium-ion storage. In solid-state batteries, the hard carbon anode can adsorb and desorb ions through these sites, improving the uniformity of lithium-ion deposition. This reversible ion storage capability ensures high capacity in solid-state batteries, thereby increasing energy density and driving range. Simultaneously, the good conductivity of hard carbon reduces internal resistance, improving charge / discharge efficiency and power performance. During charge / discharge, the volume change of the hard carbon anode is relatively small, resulting in a more stable structure that better withstands volume stress during charging and discharging, reducing electrode structure damage and pulverization. Therefore, hard carbon in the anode layer can improve battery cycle life.

[0121] In some embodiments, the metal wires and carbon materials in the negative electrode layer form a three-dimensional conductive network structure. For example, as shown in Figure 2, the negative electrode layer of the solid-state battery cell 10 contains metal wires such as silver nanowires and particulate carbon materials such as hard carbon and carbon black, forming a three-dimensional conductive network structure.

[0122] In some embodiments, the negative electrode layer also includes a binder; the binder stabilizes the metal wires and carbon materials in the negative electrode layer, forming a stable negative electrode layer and improving its stability. In the embodiments of this application, the binder forms a homogeneous system with the metal wires and carbon materials. The binder firmly bonds the metal wires and carbon materials to the surface of the negative electrode current collector, preventing the negative electrode layer material from falling off and delaminating. This bonding effect ensures the integrity and stability of the negative electrode layer, thereby improving the overall performance of the battery.

[0123] In some embodiments, the binder includes at least one of polyvinylidene fluoride (PVDF), nitrile rubber (NBR), polytetrafluoroethylene (PTFE), and sodium carboxymethyl cellulose (CMC). In this case, these binders all possess excellent binding properties, effectively binding the metal wires and carbon materials in the negative electrode layer tightly together, ensuring the stability and integrity of the battery structure, thereby improving battery efficiency and safety. Furthermore, these binders also exhibit extremely high chemical stability and corrosion resistance, maintaining their performance under various harsh environments, helping to extend battery life and reduce performance degradation caused by material aging or corrosion. They also possess good mechanical properties, resisting expansion and contraction during battery cycling and maintaining battery structural stability. When these materials are used as binders in the negative electrode layer, their internal resistance is lower, thereby improving the battery's charge and discharge efficiency.

[0124] In some embodiments, the binder content in the negative electrode layer is 1% to 10% by mass. In this case, the binder content can significantly improve the electronic and ionic conductivity of the negative electrode, while ensuring the stability and electrochemical performance of the negative electrode layer. Exemplarily, the binder content can be any typical but non-limiting point value or a range between any two points, such as 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%.

[0125] In some embodiments, the thickness of the negative electrode layer is 10 μm to 20 μm. In this case, the thickness of the negative electrode layer is beneficial to the fabrication process and can better improve the uniformity and efficiency of lithium ion transport between the solid electrolyte and the negative electrode, induce uniform deposition of lithium metal on the negative electrode side, suppress the formation of dendrites, reduce interfacial side reactions, and improve the electrochemical performance of the solid-state battery, such as coulombic efficiency, cycle stability, and safety. For example, the thickness of the negative electrode layer can be any typical but non-limiting point value or a range between any two points, such as 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 18 μm, and 20 μm.

[0126] In some embodiments, the negative electrode includes a negative electrode current collector and a negative electrode layer disposed on at least one surface of the negative electrode current collector. As an example, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode layer is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0127] In some embodiments, the negative electrode current collector can be a metal foil, a foamed metal, or a composite current collector. For example, the metal foil can be silver-treated aluminum or stainless steel, stainless steel, copper, aluminum, nickel, carbon electrodes, carbon, nickel, or titanium, etc. The foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloy, or foamed carbon, etc. In an exemplary embodiment, the composite current collector can include a composite material of a polymer and a metal, wherein the polymer can include, but is not limited to, polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc., and the metal can include, but is not limited to, elemental lithium (or elemental sodium), lithium alloy (or sodium alloy), copper, copper alloy, iron, iron alloy, tin, tin alloy, titanium, titanium alloy, silver, silver alloy. The composite current collector can be obtained by mixing polymer and metal, or the metal can be bonded to at least one side of the polymer matrix by electroplating, coating, or other methods.

[0128] In some embodiments, the negative electrode layer of the negative electrode may optionally include a conductive agent. For example, the conductive agent may be selected from at least one of superconducting carbon, acetylene black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0129] In some embodiments, the negative electrode layer of the negative electrode may optionally include other additives, such as dispersants, thickeners (e.g., sodium carboxymethyl cellulose), etc.

[0130] In some embodiments, the positive electrode includes a positive current collector, and a positive active layer is stacked on at least one surface of the positive current collector. In some embodiments, the positive active layer includes a positive electrode material, an electrolyte, and components such as a conductive agent and a binder.

[0131] In some possible implementations, the cathode material in the positive electrode active layer includes at least one of lithium nickel cobalt manganese oxide ternary cathode material, lithium nickel cobalt manganese aluminum quaternary cathode material, lithium-rich manganese-based cathode material, lithium iron phosphate, lithium manganese phosphate, lithium iron manganese phosphate, lithium manganese oxide, or nickel manganese oxide. These lithium-ion cathode materials have high specific capacity or high structural stability and good cycle performance.

[0132] In some embodiments, the mass content of the positive electrode main material contained in the positive electrode active layer of the above-mentioned positive electrode can be 90% to 98%, optionally 92% to 96%. In exemplary examples, it can be a typical but non-limiting content such as 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or any range between two content values. The positive electrode main material within this content range can effectively improve the energy density of the positive electrode.

[0133] In some possible implementations, the positive electrode active layer may further include a conductive agent and a binder. The binder enhances the mechanical properties between the positive electrode active layer itself and the current collector. The conductive agent effectively improves the conductivity of the positive electrode. As an example, the binder may include at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyacrylonitrile (PAN), polymethyl methacrylate (PMMA), polyethylene (PE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorinated acrylate resins. The conductive agent includes at least one of conductive carbon black (SP), carbon nanotubes (CNT), carbon fiber (VGCF), Ketjen black (ECP), or graphene.

[0134] In some possible implementations, the electrolyte in the positive electrode active layer can be at least one of the following: sulfide Li6PS5Cl, or binary compounds such as Li2S-GeS2, Li2S-SiS2, Li2S-P2S5, or ternary compounds such as Li2S-MeS2-P2S5 (Me = Si, Ge, Sn, Al, etc.).

[0135] In some possible implementations, the positive electrode current collector can be a metal foil, a foamed metal, or a composite current collector. For example, the metal foil can be silver-treated aluminum or stainless steel, stainless steel, copper, aluminum, nickel, carbon electrodes, carbon, nickel, or titanium, etc. The foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloys, or foamed carbon, etc. The composite current collector can include a polymeric material base layer and a metal layer. The composite current collector can be formed by forming metallic materials such as copper, copper alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys on a polymeric material substrate such as polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, or polyethylene.

[0136] In some possible implementations, the positive current collector can be made of aluminum foil, and the negative current collector can be made of copper foil.

[0137] In some possible embodiments, the solid electrolyte layer disposed between the positive and negative electrodes comprises a solid electrolyte and a binder. In some embodiments, the mass ratio of the solid electrolyte to the binder may be 100:(1-2). Exemplarily, the solid electrolyte may include at least one of polymer solid electrolytes, oxide electrolytes, sulfide electrolytes, borohydride electrolytes, composite solid electrolytes, etc. In some embodiments, the solid electrolyte includes at least one of Li6PS5Cl, or binary compounds such as Li2S-GeS2, Li2S-SiS2, Li2S-P2S5, or ternary compounds such as Li2S-MeS2-P2S5 (Me = Si, Ge, Sn, Al, etc.). Exemplarily, the binder may be at least one of polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyacrylonitrile (PAN), polymethyl methacrylate (PMMA), or polyethylene (PE).

[0138] In some possible implementations, the electrode assembly included in the solid-state battery cell 10 typically comprises a positive electrode, a negative electrode, and a solid electrolyte layer. The positive and negative electrodes are alternately stacked, and the solid electrolyte layer is stacked between the positive and negative electrodes to provide insulation, separating the positive and negative electrodes. The electrode assembly containing the solid electrolyte layer is placed in an outer package, and then encapsulated to obtain the solid-state battery cell 10.

[0139] In this embodiment, the solid-state battery cell 10 can be a rechargeable solid-state battery cell 10. A rechargeable battery refers to a solid-state battery cell 10 that can be recharged to activate the electrode active material and continue to be used after it has been discharged. The solid-state battery cell 10 can be a lithium-ion battery, a sodium lithium-ion battery, a lithium metal battery, a lithium-sulfur battery, etc., and this embodiment is not limited to this type.

[0140] In this embodiment, the solid-state battery cell 10 may include a battery casing and an electrode assembly encapsulated within the battery casing. The shape of the solid-state battery cell 10 is not particularly limited; it can be cylindrical, square, or any other arbitrary shape. Figure 1 shows a square-structured solid-state battery cell 10.

[0141] In some possible implementations, as shown in FIG3, the outer packaging of the solid-state 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. The positive electrode, solid electrolyte layer and negative electrode contained in the solid-state battery cell 10 of this application embodiment may be formed into an electrode assembly 13 by a stacking process. The electrode assembly 13 is encapsulated in the receiving cavity. The number of electrode assemblies 13 contained in the solid-state battery cell 10 may be one or more, which can be adjusted according to actual needs.

[0142] Preparation method of solid-state battery cell 10

[0143] Secondly, embodiments of this application provide a method for preparing a solid-state battery cell 10, comprising the following steps:

[0144] S10. After preparing a negative electrode slurry by combining metal wire with carbon material, binder and solvent, a negative electrode layer is formed on at least one surface of the negative electrode current collector to obtain a negative electrode;

[0145] S20. Assemble the negative electrode, positive electrode, and solid electrolyte to obtain a solid-state battery cell 10.

[0146] The method for preparing a solid-state battery cell 10 according to embodiments of this application involves forming a negative electrode slurry from metal wires, carbon materials, a binder, and a solvent, forming a negative electrode layer on the surface of the negative electrode current collector, and then assembling it with a positive electrode and a solid electrolyte to obtain the solid-state battery cell 10. The preparation process is simple and suitable for large-scale industrial production and application. The metal wires and carbon materials in the negative electrode layer form a uniformly distributed three-dimensional conductive network structure, which is beneficial to improving the uniformity of ion and electron transport in the negative electrode layer, thereby improving the uniformity of lithium-ion deposition. Furthermore, the metal wires provide abundant and uniform lithiophilic sites, continuously adsorbing lithium ions within the negative electrode layer, and simultaneously acting as diffusion channels to rapidly transfer lithium atoms into the lithium metal bulk phase, achieving uniform lithium metal deposition, suppressing dendrite growth, reducing the accumulation of byproducts such as dead lithium, and improving the cycle stability of the solid-state battery cell 10. In addition, the carbon materials in the negative electrode layer have high electronic / ionic dual conductivity, and exhibit low volume expansion effect and induced interfacial reaction during lithiation, which can reduce interfacial resistance and promote uniform lithium metal deposition. Furthermore, the metal wires also possess self-supporting properties and a certain mechanical strength, which can alleviate the volumetric strain of carbon materials during lithium deposition, thereby improving the overall structural stability of the negative electrode layer and enhancing the safety of solid-state battery cells during 10 cycles.

[0147] In step S10 above:

[0148] In some embodiments, the metal wire includes at least one of silver, zinc, aluminum, nickel, and tin wires; the metal wires formed by these metal materials have a one-dimensional structure and an excellent aspect ratio, which can improve the overall structural strength of the negative electrode layer while constructing a good electron-ion pathway. Furthermore, while enhancing electronic conductivity, the metal wires can also effectively induce the uniform deposition of lithium metal.

[0149] In some implementations, the average diameter of the metal wire is 50 nm to 100 nm.

[0150] In some implementations, the average length of the metal wire is 500 nm to 3 μm.

[0151] In some implementations, the aspect ratio of the metal wire is 10 to 600.

[0152] In some implementations, the specific surface area of ​​the metal wire is 8m². 2 / g~15m 2 / g.

[0153] In the above embodiments, the metal wires help improve the dispersion uniformity of the metal wires and carbon materials, construct a good electron-ion pathway, and improve the uniformity of lithium metal deposition.

[0154] In some embodiments, the metal wire includes a silver wire, and the preparation of the silver wire includes the steps of:

[0155] S11. Dissolve silver salt and growth-directing agent in polyol solvent to prepare silver source dispersion.

[0156] In some embodiments, the silver salt includes at least one of silver nitrate, silver sulfate, and silver halide; these silver salts all have good dissolving and dispersing properties.

[0157] In some embodiments, the growth-directing agent includes at least one of polyvinylpyrrolidone and polyether. These growth-directing agents interact with the surface of silver nanoparticles through hydrophilic groups in their molecular structure, forming an adsorption film that alters the hydrophilicity and oleophilicity of the particle surface. This adsorption film can encapsulate the particles, generating repulsive forces between the silver nanoparticles, thereby effectively preventing the aggregation and precipitation of silver nanoparticles and achieving uniform dispersion of the particles.

[0158] In some embodiments, the polyol solvent includes at least one selected from ethylene glycol, propylene glycol, glycerol, 1,2-propanediol, 1,4-butanediol, 1,6-hexanediol, and neopentyl glycol. In this case, during the preparation of silver nanowires, polyols such as ethylene glycol not only act as solvents but also as reducing agents, reducing silver ions to silver atoms to form silver nanowires. Polyols have low surface tension and high evaporation rates, which contribute to the uniform dispersion and rapid growth of silver nanowires. Furthermore, polyols contain fewer impurities, having less impact on the morphology of the silver nanowires and preserving their original appearance.

[0159] S12. After preparing the crystal form inducing agent solution, it is added to the silver source dispersion and heated to obtain silver wires. Through the combined action of these additives, such as growth guides and crystal form inducing agents, the growth direction and morphology of the silver wires are controlled to obtain silver nanowires.

[0160] In some embodiments, the crystal form inducing agent solution includes at least one of a copper salt and a zinc salt. The copper salt can be copper chloride, copper nitrate, copper sulfate, copper phosphate, etc. The zinc salt can be zinc chloride, zinc nitrate, zinc sulfate, etc.

[0161] In some embodiments, the solvent in the crystal form inducing agent solution includes at least one of ethylene glycol, propylene glycol, glycerol, 1,2-propanediol, 1,4-butanediol, 1,6-hexanediol, and neopentyl glycol.

[0162] In some embodiments, the heating reaction is carried out at a temperature of 120°C to 140°C for 1 to 2 hours. Under these reaction conditions, growth-directing agents (such as polyvinylpyrrolidone) and crystal form inducers (such as copper chloride) can be used to control the growth direction and morphology of silver nanowires, optimize their performance, and obtain silver nanowires.

[0163] In some embodiments, the silver nanowires are prepared using a one-pot method via a modified polyol method, comprising the following steps: 100 mL of ethylene glycol, 0.6 g–1.0 g of polyvinylpyrrolidone (Mw ≈ 300,000), and 0.8 g–1.2 g of silver nitrate (AgNO3) are dissolved sequentially using a magnetic stirrer. After all chemicals are completely dissolved, the stirrer is carefully removed from the mixture. Then, 1 mL–2 mL of a solution of prepared CuCl2·2H2O (3.3 mM) dissolved in ethylene glycol (EG) is rapidly injected into the mixture and gently stirred in a preheated silicone oil bath at 120°C–140°C. Subsequently, the silver nanowires are grown in the mixture at a high temperature for 1–2 hours. After growth, the mixture is washed with acetone and ethanol, vacuum filtered, and vacuum dried at 40°C–80°C for 24 hours. The resulting solid is redispersed in a solvent such as dimethyl sulfoxide to obtain a silver nanowire dispersion for later use.

[0164] In step S20 above:

[0165] In some embodiments, the carbon material includes at least one of hard carbon, carbon black, soft carbon, graphene, carbon nanotubes, natural graphite, and artificial graphite. These carbon materials not only possess high electronic / ionic conductivity, but also exhibit low volume expansion during lithiation, with negligible volume expansion after lithium intercalation. Particulate carbon materials, in particular, provide better inter-filling with the metal wires, reducing porosity between the negative electrode layers and improving the uniformity of the negative electrode layer, thereby enhancing the uniformity of lithium metal deposition.

[0166] In some embodiments, the mass ratio of metal wire to carbon material is 1:(1-10). In this case, the structural stability of the metal wire and carbon material is sufficiently ensured, the volume expansion of the negative electrode layer during cycling is reduced, and the structural damage of the solid-state battery cell 10 during cycling is suppressed. At the same time, it can guide the uniform transport of lithium ions in the intermediate layer, improve the uniformity of lithium ion transport and deposition, suppress the formation of dendrites, and improve the electrochemical performance of the solid-state battery, such as coulombic efficiency, cycle stability, and safety.

[0167] In some embodiments, the carbon material is in particulate form, with a particle size Dv50 of 20 nm to 2 μm for each individual particle.

[0168] In some embodiments, the specific surface area of ​​the carbon material is 30 m². 2 / g~500m 2 / g.

[0169] In some embodiments, the compaction density of the carbon material is 0.7 g / cm³. 3 ~0.9g / cm 3 .

[0170] In some embodiments, the carbon material has mesoporous and microporous structures.

[0171] In some implementations, the pore size of mesopores is 2nm to 50nm, and the pore size of micropores is no higher than 2nm.

[0172] In the above embodiments, carbon materials have high electronic / ionic conductivity, exhibit low volume expansion effect and induced interfacial reaction during lithiation, forming excellent ion and electron transport channels, reducing interfacial resistance, and promoting uniform lithium metal deposition.

[0173] In some embodiments, the binder includes at least one of polyvinylidene fluoride, nitrile rubber, polytetrafluoroethylene, and sodium carboxymethyl cellulose. These binders all possess excellent binding properties, effectively binding the metal wires and carbon materials in the negative electrode layer tightly together, ensuring the stability and integrity of the battery structure, thereby improving the battery's efficiency and safety.

[0174] In some embodiments, the total mass ratio of the metal wire and carbon material to the binder is (90–99):(1–10). In this case, the binder content can significantly improve the electronic and ionic conductivity of the negative electrode, while ensuring the stability and electrochemical performance of the negative electrode layer.

[0175] In some embodiments, the thickness of the negative electrode layer on the surface of the negative electrode current collector is 10 μm to 20 μm. In this case, the thickness of the negative electrode layer is beneficial to the process preparation and can better improve the uniformity and efficiency of lithium ion transport between the solid electrolyte and the negative electrode, induce uniform deposition of lithium metal on the negative electrode side, suppress the formation of dendrites, reduce interfacial side reactions, and improve the electrochemical performance of solid-state batteries, such as coulombic efficiency, cycle stability, and safety.

[0176] In some possible implementations, the preparation steps of the negative electrode include: making a negative electrode slurry by combining the above-mentioned metal wire with carbon material, binder and solvent, coating the negative electrode slurry onto the surface of the negative electrode current collector, and then performing steps such as drying, rolling and die cutting.

[0177] In step S30 above, a positive electrode and a solid electrolyte are provided, and the positive electrode, solid electrolyte and negative electrode are assembled to obtain a solid battery cell 10.

[0178] In some possible implementations, the preparation steps of the positive electrode include: after preparing a slurry for the positive electrode active layer, coating the slurry for the positive electrode active layer onto the surface of the positive electrode current collector, and then performing steps such as drying, rolling, and die cutting.

[0179] In some possible implementations, a positive electrode, a solid electrolyte, and a negative electrode can be stacked to form a solid-state battery cell 10. As an example, a positive electrode, a solid electrolyte, and a negative electrode can be stacked to form an electrode assembly 13. The electrode assembly 13 is placed in an outer package and subjected to processes such as vacuum sealing, settling, formation, and shaping to obtain the solid-state battery cell 10.

[0180] In this application embodiment, the solid-state battery cell 10 refers to a solid-state battery assembly including a battery casing and a solid-state battery cell encapsulated within the battery casing. The shape of the solid-state battery cell 10 is not particularly limited; it can be cylindrical, square, or any other arbitrary shape. In the exemplary example, the solid-state battery cell 10 can be a square-structured solid-state battery cell 10 as shown in FIG1.

[0181] Battery device

[0182] Thirdly, embodiments of this application provide a battery device, including a solid-state battery cell 10 provided in the first aspect of embodiments of this application or a solid-state battery cell 10 prepared by the preparation method provided in the second aspect of embodiments of this application.

[0183] The battery device provided in this application embodiment is based on the solid-state battery cell 10 of this application embodiment. Therefore, the battery device of this application embodiment has a good cycle life under the premise of high energy density.

[0184] The battery apparatus mentioned in the embodiments of this application may include one or more solid-state battery cells 10 for providing voltage and capacity. The solid-state battery cell assembly may include multiple solid-state battery cells 10, which are connected in series, parallel, or mixed connection via a busbar.

[0185] In some embodiments, the battery device of this application may include any one of a solid-state battery cell 10, a battery module, or a battery pack.

[0186] A battery module is assembled from the solid-state battery cell 10, which means it can contain multiple solid-state battery cells 10. The specific number can be adjusted according to the application and capacity of the battery module.

[0187] In some embodiments, as shown in Figure 4, which is a schematic diagram of a battery module 20 as an example, a plurality of solid-state battery cells 10 may be arranged sequentially along the length of the battery module 20. Of course, they can also be arranged in any other manner. The plurality of solid-state battery cells 10 can be secured with fasteners. Optionally, the battery module 20 may further include a housing with a receiving space in which the plurality of solid-state battery cells 10 are received.

[0188] A battery pack refers to an assembly of solid-state battery cells 10, as described above. It can contain multiple solid-state battery cells 10, which can be assembled into a battery module 20. The specific number of solid-state battery cells 10 or battery modules 20 contained in the battery pack can be adjusted according to the application and capacity of the battery pack.

[0189] As shown in the embodiments, Figures 5 and 6 are schematic diagrams of a battery pack 30 as an example. The battery pack 30 may include a battery box and a plurality of battery modules 20 disposed within the battery box. The battery box includes an upper box 31 and a lower box 32, the upper box 31 covering the lower box 32 and forming a closed space for accommodating the battery modules 20. The plurality of battery modules 20 may be arranged in any manner within the battery box.

[0190] Electrical appliances

[0191] Fourthly, embodiments of this application provide an electrical device, including a solid-state battery cell 10 provided in the first aspect of this application, a solid-state battery cell 10 prepared by the preparation method provided in the second aspect of this application, or a battery device provided in the third aspect of this application.

[0192] The electrical device provided in this application embodiment is based on the solid-state battery cell 10 or battery device of this application embodiment, therefore the electrical device of this application embodiment can work safely and for a long time.

[0193] In some implementations, the electrical device may be, but is not limited to, mobile devices (e.g., mobile phones, portable devices, laptops, etc.), electric vehicles (e.g., pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, electric vehicles, electric toys, power tools, etc.), electric trains, ships, satellites and spacecraft, energy storage systems, etc. The electrical device may be configured with sub-solid-state battery cells 10, battery modules, or battery packs according to its usage requirements.

[0194] Figure 7 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.

[0195] 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.

[0196] Energy storage devices

[0197] Fifthly, embodiments of this application provide an energy storage device, including a solid-state battery cell 10 provided in the first aspect of embodiments of this application, a solid-state battery cell 10 prepared by the preparation method provided in the second aspect of embodiments of this application, or a battery device provided in the third aspect of embodiments of this application.

[0198] Since the energy storage device in this application embodiment contains the solid-state battery cell 10 or battery device described in the above application embodiment, the energy storage device has high energy density, good cycle performance, and long service life.

[0199] In some embodiments, 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.

[0200] In some implementations, 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.

[0201] In some implementations, the energy storage device is an energy storage container or an energy storage cabinet.

[0202] In some implementations, the energy storage device may include a cabinet and one or more battery clusters housed within the cabinet.

[0203] 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.

[0204] negative electrode of solid-state battery cell 10

[0205] In a sixth aspect, this application provides a negative electrode for a solid-state battery cell 10, the negative electrode including a negative electrode current collector and a negative electrode layer stacked on at least one surface of the negative electrode current collector, the negative electrode layer including metal wires and carbon materials.

[0206] In the negative electrode of the solid-state battery cell 10 of this application embodiment, the metal wires and carbon materials included in the negative electrode layer on the surface of the negative electrode current collector not only enhance the conductivity of ions and electrons, but also reduce the loss of effective contact area caused by volume changes, and can make electrons uniformly distributed, thereby optimizing the lithium deposition behavior. This can effectively induce uniform lithium metal deposition and improve the safety of the solid-state battery cell 10 during cycling.

[0207] Example

[0208] 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.

[0209] Example 1

[0210] A solid-state battery cell 10 is prepared by the following steps:

[0211] 1. Preparation of silver nanowires: Using a magnetic stirrer, 100 mL of ethylene glycol (EG), 0.8 g of polyvinylpyrrolidone (Mw≈300000), and 1 g of silver nitrate (AgNO3) were dissolved sequentially. After all chemicals were completely dissolved, the stirrer was carefully removed from the mixture. Then, 1.6 mL of a solution of 3.3 mM CuCl2·2H2O in ethylene glycol was rapidly injected into the mixture and gently stirred in a preheated silicone oil bath at 130 °C. Subsequently, the silver nanowires were grown in the mixture at a high temperature for 1.5 hours. After growth, the mixture was washed with acetone and ethanol, vacuum filtered, and vacuum dried at 60 °C for 24 hours. The resulting solid was redispersed in dimethyl sulfoxide (DMSO) to obtain a silver nanowire dispersion (concentration 4 mg / mL).

[0212] 2. Preparation of the negative electrode sheet: A dispersion of silver nanowires, hard carbon, and PVDF binder are mixed, with a mass ratio of silver nanowires to hard carbon of 1:3 and a total mass ratio of silver nanowires and hard carbon to PVDF of 95:5. NMP solvent is added, and the mixture is thoroughly stirred to obtain a uniform negative electrode slurry. The negative electrode slurry is coated onto copper foil, dried, and cold-pressed to obtain a negative electrode sheet with a thickness of 10 μm.

[0213] 3. Dry preparation of positive electrode sheet: The positive electrode active layer is prepared by dry mixing of positive electrode main material lithium nickel cobalt manganese oxide, conductive agent conductive carbon black and solid electrolyte sulfide in a mass ratio of 70:5:30. After rolling and cutting, the positive electrode active layer is combined with the positive electrode current collector to obtain the positive electrode sheet.

[0214] 4. Preparation of solid electrolyte layer: The electrolyte layer is prepared by mixing electrolyte and binder at a ratio of 100:1.

[0215] 5. Battery assembly: The cells are assembled in the order of positive electrode-solid electrolyte-negative electrode stacking, and after high-temperature densification treatment, a soft-pack battery is obtained.

[0216] Example 2-Example 3

[0217] Examples 2 and 3 each provide a solid-state battery cell 10, which differs from Example 1 in that the carbon material in the negative electrode layer is different, as shown in Table 1 below.

[0218] Examples 4-14

[0219] Examples 4-14 each provide a solid-state battery cell 10, which differs from Example 1 in that the ratio of metal wire to carbon material is different, as shown in Table 1 below.

[0220] Example 15

[0221] A solid-state battery cell 10 differs from Example 1 in that the material of the metal wire is different, as shown in Table 1 below.

[0222] Example 16

[0223] A solid-state battery cell 10 differs from Example 1 in that the carbon material in the negative electrode layer is carbon nanotubes, as shown in Table 1 below.

[0224] Comparative Example 1

[0225] A solid-state battery cell 10 differs from Example 1 in that hard carbon is added to the negative electrode layer, but no silver wire is added, as shown in Table 1 below.

[0226] Comparative Example 2

[0227] A solid-state battery cell 10 differs from Example 1 in that carbon black is added to the negative electrode layer, but no silver wire is added, as shown in Table 1 below.

[0228] Comparative Example 3

[0229] A solid-state battery cell 10 differs from Example 1 in that: no carbon material is added to the negative electrode layer, but silver wires are added, as shown in Table 1 below.

[0230] Comparative Example 4

[0231] A solid-state battery cell 10 differs from Example 1 in that hard carbon + silver nanoparticles are added to the negative electrode layer, as shown in Table 1 below.

[0232] Comparative Example 5

[0233] A solid-state battery cell 10 differs from Example 1 in that carbon nanotubes and silver nanoparticles are added to the negative electrode layer, as shown in Table 1 below.

[0234] The substances used in the above embodiments and comparative examples are shown in Table 1 below, wherein:

[0235] 1. The test method / standard for particle size Dv50 is: laser particle size analyzer test;

[0236] 2. The test method / standard for the specific surface area of ​​carbon materials is: low-temperature nitrogen adsorption method;

[0237] 3. The test method / standard for the compaction density of carbon materials is: powder compaction density meter;

[0238] 4. The test method / standard for the mesopore and micropore content of carbon materials is: Brunauer-Emmett-Teller specific surface area test method;

[0239] 5. The testing method / standard for the diameter and length of the metal wire is: observation using a scanning electron microscope;

[0240] 6. The test method / standard for the specific surface area of ​​metal wires is: low-temperature nitrogen adsorption method;

[0241] The test results are shown in Table 1 below:

[0242] Table 1

[0243] Performance testing:

[0244] The following performance tests were performed on the above embodiments and comparative examples:

[0245] 1. First-cycle discharge capacity (mAh / g) test conditions: 60℃, loading pressure 50MPa, 0.1C charging, 0.1C discharging;

[0246] 2. First-cycle coulombic efficiency (%) test conditions: 60℃, loading pressure 50MPa, 0.1C charging, 0.1C discharging;

[0247] 3. 2C discharge capacity (mAh / g) test conditions: 60℃, loading pressure 50MPa, 0.1C charging, 0.2C discharging;

[0248] 4. Capacity retention rate (%) after 100 cycles: 60℃, loading pressure 50MPa, 0.33C charging, 0.33C discharging, 100 cycles;

[0249] The test results are shown in Table 2 below:

[0250] Table 2

[0251] As can be seen from the above test results, the interaction between the metal wires and carbon materials in the negative electrode layer of this application embodiment can achieve uniform lithium metal deposition, suppress dendrite growth, reduce the accumulation of by-products such as dead lithium, and improve the cycle stability of the battery.

[0252] A comparison of Examples 1 and 4-14 shows that the ratio of metal wire to carbon material affects the performance of the battery. When the mass ratio of metal wire to carbon material is 1:(1-10), the battery exhibits higher electrical performance.

[0253] By comparing Example 1 and Example 15, it can be seen that silver nanowires can better induce uniform lithium deposition and can better improve the battery's first efficiency and cycle stability.

[0254] By comparing Example 1 and Example 16, it can be seen that the carbon material using granular hard carbon has a better interaction with the silver wire, which can significantly improve the electrical performance of the battery.

[0255] 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 battery cell comprising a positive electrode and a negative electrode and a solid-state electrolyte layer disposed between the positive and negative electrodes, characterized by: The negative electrode includes a negative electrode current collector and a negative electrode layer stacked on at least one surface of the negative electrode current collector, wherein the negative electrode layer includes metal wires and carbon materials.

2. The solid-state battery cell of claim 1, wherein, In the negative electrode layer, the mass ratio of the metal wire to the carbon material is 1:(1~10); And / or, in the negative electrode layer, the metal wires and the carbon material form a three-dimensional conductive network structure; And / or, the morphology of the carbon material includes particulate form.

3. The solid-state battery cell according to claim 1 or 2, wherein The metal wire has at least one of the following features (1) to (5): (1) The metal material in the metal wire includes at least one of Ag, Zn, Al, Sn, and Ni; (2) The average diameter of the metal wire is 50 nm to 100 nm; (3) The average length of the metal wire is 500 nm to 3 μm; (4) The aspect ratio of the metal wire is 10 to 600; (5) the specific surface area of the metal wire is 8 m 2 / g ~ 15 m 2 / g.

4. The solid-state battery cell according to any one of claims 1 to 3, wherein The carbon material possesses at least one of the following characteristics (1) to (5): (1) The carbon material includes at least one of hard carbon, carbon black, soft carbon, graphene, carbon nanotubes, natural graphite, and artificial graphite; (2) The carbon material is in particulate form, and the particle size Dv50 of a single particle is 20nm to 2μm; (3) the specific surface area of the carbon material is 30 m 2 / g to 500 m 2 / g; (4) the carbon material has a compacted density of 0.7 g / cm 3 ~ 0.9 g / cm 3 ; (5) The carbon material has mesoporous and microporous structures.

5. The solid-state battery cell of claim 4, wherein, The pore size of the mesopores is 2nm to 50nm, and the pore size of the micropores is no higher than 2nm; And / or, in the carbon material, the volume percentage of mesopores is 5% to 30%, and the volume percentage of micropores is not higher than 60%; And / or, the porosity of the carbon material is 30% to 60%.

6. The solid-state battery cell of claim 4 or 5, wherein, The carbon material includes carbon black, which has at least one of the following characteristics (1) to (3): (1) The particle size Dv50 of the individual carbon black particles is 20nm to 100nm; (2) the carbon black has a specific surface area of 50 m 2 / g to 500 m 2 / g; (3) the carbon black has a tap density of 0.7 g / cm 3 ~ 0.9 g / cm 3 ; And / or, the carbon material includes hard carbon, which has at least one of the following characteristics (1) to (4): (1) The particle size Dv50 of the individual hard carbon particles is 50 nm to 2 μm; (2) the specific surface area of the hard carbon is 50 m 2 / g to 500 m 2 / g; (3) the hard carbon has a compacted density of 0.75 g / cm 3 ~ 0.9 g / cm 3 ; (4) In the hard carbon, the volume percentage of mesopores is 5% to 30%, and the volume percentage of micropores is not higher than 60%.

7. The solid-state battery cell according to any one of claims 1 to 6, wherein The negative electrode layer also includes a binder; And / or, the thickness of the negative electrode layer is 10 μm to 20 μm.

8. The solid state battery cell of claim 7, wherein, The adhesive includes at least one of polyvinylidene fluoride, nitrile rubber, polytetrafluoroethylene, and sodium carboxymethyl cellulose; And / or, in the negative electrode layer, the mass percentage of the binder is 1% to 10%.

9. A method of producing a solid-state battery cell, characterized by, Includes the following steps: After preparing a negative electrode slurry by combining metal wire with carbon material, binder and solvent, a negative electrode layer is formed on at least one surface of the negative electrode current collector to obtain a negative electrode. The negative electrode is assembled with the positive electrode and a solid electrolyte to obtain a solid-state battery cell.

10. The method of producing a solid-state battery cell according to claim 9, wherein The metal wire includes at least one of silver wire, zinc wire, aluminum wire, nickel wire, and tin wire; And / or, the carbon material includes at least one of hard carbon, carbon black, soft carbon, graphene, carbon nanotubes, natural graphite, and artificial graphite; And / or, the adhesive includes at least one of polyvinylidene fluoride, nitrile rubber, polytetrafluoroethylene, and sodium carboxymethyl cellulose; And / or, the mass ratio of the metal wire to the carbon material is 1:(1-10); And / or, the total mass ratio of the metal wire and the carbon material to the mass ratio of the binder is (90-99):(1-10); And / or, the thickness of the negative electrode layer on the surface of the negative electrode current collector is 10 μm to 20 μm.

11. The method of producing a solid-state battery cell according to claim 10, wherein The metal wire includes a silver wire, and the preparation of the silver wire includes the following steps: Silver source dispersion was prepared by dissolving silver salt and growth guide agent in polyol solvent; After preparing the crystal form inducing agent solution, it was added to the silver source dispersion and heated to obtain silver wire.

12. The method of producing a solid-state battery cell according to claim 11, wherein The polyol solvent includes at least one of ethylene glycol, propylene glycol, glycerol, 1,2-propanediol, 1,4-butanediol, 1,6-hexanediol, and neopentyl glycol; And / or, the growth-directing agent includes at least one of polyvinylpyrrolidone and polyether; And / or, the silver salt includes at least one of silver nitrate, silver sulfate, and silver halide; And / or, in the crystal form inducing agent solution, the crystal form inducing agent includes at least one of copper salt and zinc salt; And / or, in the crystal form inducing agent solution, the solvent includes at least one of ethylene glycol, propylene glycol, glycerol, 1,2-propanediol, 1,4-butanediol, 1,6-hexanediol, and neopentyl glycol; And / or, the temperature conditions for the heating reaction are 120℃~140℃, and the reaction time is 1h~2h.

13. A battery device characterized by comprising: Includes solid-state battery cells as described in any one of claims 1 to 8 or solid-state battery cells prepared by the preparation methods described in claims 9 to 12.

14. An electrical device, characterized by Includes solid-state battery cells as described in any one of claims 1 to 8, solid-state battery cells prepared by the preparation methods described in claims 9 to 12, or battery devices as described in claim 13.

15. An energy storage device, characterized by Includes solid-state battery cells as described in any one of claims 1 to 8, solid-state battery cells prepared by the preparation methods described in claims 9 to 12, or battery devices as described in claim 13.

16. A negative electrode of a solid-state battery cell, characterized by The negative electrode includes a negative electrode current collector and a negative electrode layer stacked on at least one surface of the negative electrode current collector, wherein the negative electrode layer includes metal wires and carbon materials.

Images