Solid-state electrolyte membrane and preparation method therefor, solid-state battery and electric device

Abstract

A solid-state electrolyte membrane and a preparation method therefor, a solid-state battery and an electric device. The solid-state electrolyte membrane comprises a solid-state electrolyte material layer, a phase transformation toughening agent and a fiber material, wherein the phase transformation toughening agent and the fiber material are dispersed in the solid-state electrolyte material layer, and the solid-state electrolyte material layer comprises an inorganic ceramic solid-state electrolyte material. In the solid-state electrolyte membrane, by means of the synergistic effect of the phase transformation toughening agent and the fiber material in the solid electrolyte material layer, the mechanical properties, especially the fracture toughness, of the solid-state electrolyte membrane can be effectively improved, such that the problems of dendrites, short circuits, etc., caused by breakage are reduced.

Description

Solid electrolyte membrane and preparation method thereof, solid-state battery, and electrical device

[0001] Cross-references

[0002] This application refers to Chinese Patent Application No. 2023104881248 filed on May 4, 2023, entitled “Solid electrolyte membrane and preparation method thereof, solid-state battery, and electrical device”, which is incorporated into this application in its entirety by reference. Technical Field

[0003] The present application relates to the field of battery technology, and in particular to a solid electrolyte membrane and a preparation method thereof, a solid-state battery, and an electrical device. Background Art

[0004] In recent years, the application of batteries has become increasingly widespread. They are widely used in energy storage systems such as hydropower, thermal, wind, and solar power plants, as well as in power tools, electric bicycles, electric motorcycles, electric vehicles, military equipment, aerospace, and other fields. Advances in battery research have led to the emergence of solid-state batteries, which have been seen as a potential successor to lithium-ion batteries. Solid-state lithium battery technology replaces liquid electrolytes with solid electrolytes, significantly increasing the energy density of lithium batteries.

[0005] Currently, solid electrolytes can be divided into polymer solid electrolytes and inorganic ceramic solid electrolytes. Compared with polymer solid electrolytes, the fragile mechanical properties of inorganic ceramic solid electrolytes are the core bottleneck of their application.

[0006] Summary of the Invention

[0007] Based on this, the present application provides a solid electrolyte membrane and a preparation method thereof, a solid-state battery, and an electrical device. The solid electrolyte membrane has good mechanical properties.

[0008] In a first aspect of the present application, a solid electrolyte membrane is provided, comprising a solid electrolyte material layer and a phase change toughening agent and a fiber material dispersed in the solid electrolyte material layer, wherein the solid electrolyte material layer comprises an inorganic ceramic solid electrolyte material.

[0009] The above-mentioned solid electrolyte membrane can effectively improve the mechanical properties of the solid electrolyte membrane, especially the fracture toughness, through the synergistic effect between the phase change toughening agent and the fiber material in the solid electrolyte material layer, thereby reducing problems such as dendrites and short circuits caused by fracture of the solid electrolyte membrane.

[0010] In one embodiment, the phase change toughening agent includes metastable ZrO2; optionally, the phase change toughening agent includes one or more of yttria-stabilized zirconia (YSZ), scandia-stabilized zirconia (SSZ), magnesia-stabilized zirconia (MSZ), calcia-stabilized zirconia (CSZ) and cesium oxide-stabilized zirconia (CsSZ).

[0011] In one embodiment, the fiber material includes ceramic fiber; optionally, the fiber material includes one or more of silicon carbide fiber, silicon nitride fiber, boron nitride fiber, alumina fiber and silica fiber.

[0012] In one embodiment, the total volume of the phase change toughening agent and the fiber material in the solid electrolyte material layer is 5% to 20% by volume; optionally, the volume percentage is 8% to 12%.

[0013] In one embodiment, the volume ratio of the phase change toughening agent to the fiber material is 1:(0.25-4); optionally, the volume ratio is 1:(0.5-1.5).

[0014] In one embodiment, the phase change toughening agent D 50 =50nm~100nm.

[0015] In one embodiment, the fiber material has a diameter of 0.5 μm to 5 μm and a length of 10 μm to 30 μm.

[0016] In one embodiment, the inorganic ceramic solid electrolyte material includes a lithium ion solid electrolyte material, a sodium ion solid electrolyte material, or a potassium ion solid electrolyte material.

[0017] In one embodiment, the solid electrolyte membrane has one or more of the following features (1) to (2):

[0018] (1) The fracture toughness of the solid electrolyte membrane is ≥ 0.25 MPa·m 1 / 2 ; Optionally, the fracture toughness of the solid electrolyte membrane is ≥1.5MPa·m 1 / 2 ;

[0019] (2) The critical current density of the solid electrolyte membrane is ≥1.5 mA / cm 2 ; Optionally, the critical current density of the solid electrolyte membrane is ≥2mA / cm 2 .

[0020] The second aspect of the present application provides a method for preparing the solid electrolyte membrane according to the first aspect, comprising the following steps:

[0021] Mixing the inorganic ceramic solid electrolyte material, the phase change toughening agent and the fiber material to prepare a mixture;

[0022] The mixed material is molded to prepare the solid electrolyte membrane.

[0023] The preparation method of the solid electrolyte membrane is simple in steps and is easy to promote and apply industrially.

[0024] In one embodiment, the mixing is dry mixing.

[0025] In one embodiment, the forming process is a pressurization process; optionally, the pressure of the pressurization process is 300 MPa to 600 MPa.

[0026] In one embodiment, the mixing is wet mixing.

[0027] In one embodiment, the molding process includes coating the mixture into a film and drying the mixture; optionally, the solvent used in the wet mixing process includes one or more of toluene, p-xylene, o-xylene, m-xylene, trimethylbenzene, ethyl acetate, butyl butyrate, n-butyl ether, anisole, ethylene glycol dimethyl ether, ethylene glycol diethyl ether and n-butane.

[0028] The third aspect of the present application provides a solid-state battery, comprising the solid-state electrolyte membrane described in the first aspect.

[0029] The fourth aspect of the present application provides an electrical device comprising the solid-state battery described in the third aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments of the present application. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on the drawings without inventive work. In the drawings:

[0031] FIG1 is a schematic diagram of a solid-state battery according to one embodiment of the present application;

[0032] FIG2 is a schematic diagram of a battery module according to an embodiment of the present application;

[0033] FIG3 is a schematic diagram of a battery pack according to an embodiment of the present application;

[0034] FIG4 is an exploded view of the battery pack shown in FIG3 according to an embodiment of the present application;

[0035] FIG5 is a schematic diagram of an electrical device using a solid-state battery as a power source according to an embodiment of the present application;

[0036] FIG6 is a scanning electron microscope image of a cross section of a solid electrolyte membrane prepared in one embodiment of the present application;

[0037] Explanation of the accompanying figures: 1: battery pack; 2: upper box; 3: lower box; 4: battery module; 5: solid-state battery; 6: electrical device. DETAILED DESCRIPTION

[0038] Hereinafter, the embodiments of the solid electrolyte membrane and its preparation method, solid-state battery, and electrical device of the present application will be described in detail with appropriate reference to the accompanying drawings. However, there may be cases where unnecessary detailed descriptions are omitted. For example, there are cases where detailed descriptions of well-known matters and repeated descriptions of actually the same structures are omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate the understanding of those skilled in the art. In addition, the drawings and the following description are provided for those skilled in the art to fully understand the present application and are not intended to limit the subject matter described in the claims.

[0039] " range " disclosed in the present application is limited in the form of lower limit and upper limit, and given range is limited by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundary of special range. The scope limited in this way can be to include end value or not include end value, and can be arbitrarily combined, that is, any lower limit can form a range with any upper limit combination. For example, if the scope of 60-120 and 80-110 is listed for specific parameters, it is understood that the scope of 60-110 and 80-120 is also expected. In addition, if the minimum range value 1 and 2 are listed, and if the maximum range value 3,4 and 5 are listed, then the following range can all be expected: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5. In this application, unless otherwise specified, the numerical range " ab " represents the abbreviation of any real number combination between a and b, wherein a and b are all real numbers. For example, a numerical range of "0-5" indicates that all real numbers between "0-5" are listed herein, and "0-5" is simply an abbreviation for these numerical combinations. Furthermore, when a parameter is expressed as an integer ≥ 2, this is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0040] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0041] Unless otherwise specified, all technical features and optional technical features of this application can be combined with each other to form a new technical solution.

[0042] Unless otherwise specified, all steps of the present application may be performed sequentially or randomly, and in some examples are performed sequentially. For example, the method includes steps (a) and (b), which means that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, the method may further include step (c), which means that step (c) may be added to the method in any order, for example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.

[0043] Unless otherwise specified, the terms "include" and "comprising" used in this application may be open-ended or closed-ended. For example, "include" and "comprising" may mean that other components not listed may also be included or that only the listed components are included.

[0044] Unless otherwise specified, the term "or" is used in this application to be inclusive. For example, the phrase "A or B" means "A, B, or both A and B." More specifically, the condition "A or B" is satisfied if any of the following conditions are met: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0045] In this application, the definition and test method of fracture toughness are as follows:

[0046] Definition: Fracture toughness describes a material's ability to absorb strain energy before fracture. Higher fracture toughness indicates greater resistance to crack propagation. It also reflects the solid electrolyte membrane's resistance to dendrite-induced cracking and short circuiting. Fracture toughness can be measured using methods such as the four-point bend test and the Vickers cone indentation test. In this application, the Vickers cone indentation test was used.

[0047] Test method: The prepared solid electrolyte membrane is polished with sandpaper on the surface of the solid electrolyte sheet in an argon atmosphere, from 800 mesh, to 2000 mesh, to 4000 mesh, to 8000 mesh, until the electrolyte surface presents mirror properties without obvious defects. Then, the polished surface is subjected to an indentation test using a Vickers cone indentation tester. The indentation tester is driven with an appropriate load until radial cracks appear at the four corners of the cone indentation. Based on the indentation load P, the extension length C of the radial crack, the Young's modulus E and the microhardness HV, the fracture toughness value K can be calculated using the following formula. IC :

[0048] In this application, the definition and test method of critical current density are as follows:

[0049] Definition: Critical current density refers to the minimum current density at which dendrites and short circuits occur when electrochemical deposition of a solid electrolyte membrane occurs with a corresponding alkali metal electrode. In other words, when electrochemical deposition of a solid electrolyte membrane occurs below the critical current density, dendrites and short circuits will not occur. Critical current density is a core indicator of the ability of a solid electrolyte membrane to suppress dendrites and short circuits.

[0050] Test method: The critical current density of the solid electrolyte membrane is measured by the traditional symmetrical battery step-by-step increase current density cycle method. Taking lithium-ion solid electrolyte as an example, the prepared solid electrolyte membrane is taken. Two 8 mm (mm) dendrites and 50 μm thick lithium metal discs are placed in the center of the two symmetrical sides of the electrolyte. Mechanical pressure will make the lithium metal and the electrolyte sheet fit tightly together to form a lithium / solid electrolyte / lithium pair precipitation pool. After the symmetrical battery is assembled and packaged, the lithium / solid electrolyte / lithium symmetrical battery is increased from 0.25 mA per square centimeter (mA / cm 2 ) and sequentially deposited and stripped 1 mAh / cm 2 ) After lithium, the current was increased to 0.5 mA / cm 2 , maintain 1mAh / cm 2 After the surface capacity deposition and stripping, the 2 , 1.0mA / cm 2 , 1.25mA / cm 2 ...to 10mA / cm 2 The current density at which the voltage suddenly drops sharply is recorded as the critical current density.

[0051] Currently, inorganic ceramic solid electrolytes are prone to fracture due to their fragile mechanical properties, and are prone to dendrite formation and short circuits when deposited on the negative electrode side. Traditionally, fibers have been introduced into the solid electrolyte to improve the mechanical properties of the solid electrolyte membrane, thereby reducing the dendrite formation and short circuits caused by fracture. However, this approach has limited improvements in mechanical properties.

[0052] Based on this, some examples of the present application provide a solid electrolyte membrane, comprising a solid electrolyte material layer and a phase change toughening agent and a fiber material dispersed in the solid electrolyte material layer, wherein the solid electrolyte material layer comprises an inorganic ceramic solid electrolyte material.

[0053] The above-mentioned solid electrolyte membrane disperses phase change toughening agent and fiber material in the solid electrolyte material layer. There is a synergistic effect between the phase change toughening agent and the fiber material, forming an internal structure similar to "reinforced concrete", which can effectively improve the mechanical properties of the solid electrolyte membrane, especially the fracture toughness, thereby reducing problems such as dendrites and short circuits caused by fracture.

[0054] In addition, during the research process, it was found that when defects and dendrites are generated in the solid electrolyte, the tensile stress generated by local expansion will also cause the surrounding phase change toughening agent to undergo an in-situ phase change and generate compressive stress to further reduce the formation of defects and dendrites, thereby improving the mechanical properties of the solid electrolyte membrane and significantly increasing the critical current density of the solid electrolyte.

[0055] Furthermore, by rationally selecting the types of phase change toughening agents and fiber materials, the synergistic effect of phase change toughening and fiber toughening can be maximized, thereby achieving higher fracture toughness and critical current density.

[0056] In some examples, the phase change toughening agent includes metastable ZrO2. Furthermore, the phase change toughening agent includes one or more of yttria-stabilized zirconia (YSZ), scandia-stabilized zirconia (SSZ), magnesia-stabilized zirconia (MSZ), calcia-stabilized zirconia (CSZ), and cesium-stabilized zirconia (CsSZ). Furthermore, the phase change toughening agent includes yttria-stabilized zirconia (YSZ). By properly selecting the type of phase change toughening agent, higher fracture toughness and critical current density can be achieved.

[0057] In some examples, the fiber material includes ceramic fiber. In addition to optimizing fracture toughness and critical current density, ceramic fiber itself has no ion conduction ability, which also reduces the occurrence of fiber-induced deposition in traditional methods. Furthermore, the fiber material includes one or more of silicon carbide fiber, silicon nitride fiber, boron nitride fiber, aluminum oxide fiber and silicon dioxide fiber. Furthermore, the fiber material includes one or more of silicon carbide fiber, silicon nitride fiber, aluminum oxide fiber and silicon dioxide fiber. By rationally selecting the type of fiber material, higher fracture toughness and critical current density can be achieved.

[0058] Furthermore, by rationally selecting the total volume proportion of the phase change toughening agent and the fiber material in the solid electrolyte material layer, the influence of the phase change toughening agent and the fiber material on the ion conduction and percolation in the solid electrolyte material can be controlled, thereby achieving a better fracture toughness improvement effect while also improving the critical current density.

[0059] In some examples, the total volume of the phase change toughening agent and the fiber material in the solid electrolyte material layer is 5% to 20% by volume. Specifically, the volume percentage includes but is not limited to: 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, or a range between any two of the foregoing values. Furthermore, the volume percentage is 8% to 12%.

[0060] Furthermore, by rationally selecting the volume ratio of the phase change toughening agent to the fiber material, better fracture toughness and critical current density levels can be achieved.

[0061] In some examples, the volume ratio of the phase change toughening agent to the fiber material is 1:(0.25-4). Specifically, the volume ratio includes but is not limited to: 1:0.25, 1:0.5, 1:0.8, 1:1, 1:1.2, 1:1.5, 1:2, 1:3, 1:35, 4, or a range between any two of the foregoing values. Furthermore, the volume ratio is 1:(0.5-1.5).

[0062] Furthermore, by rationally selecting the ratio and size of the phase change toughening agent and the fiber material, a multi-scale structural toughening and dendrite inhibition structure can be formed, thereby achieving better fracture toughness and critical current density levels.

[0063] In some examples, the phase change toughening agent has a D 50 =50 nanometers (nm) to 100 nm. Specifically, the D 50 Including but not limited to: 50nm, 55nm, 60nm, 65nm, 70nm, 75nm, 80nm, 85nm, 90nm, 95nm, 100nm or a range between any two of the foregoing values.

[0064] In some examples, the diameter of the fiber material is 0.5 micrometers (μm) to 5 μm, and the length is 10 μm to 30 μm. Specifically, the diameter of the fiber material includes but is not limited to: 0.5 μm, 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, 5 μm or a range between any two of the foregoing values. The length of the fiber material includes but is not limited to: 10 μm, 15 μm, 20 μm, 25 μm, 30 μm or a range between any two of the foregoing values. Further, the diameter of the fiber material is 0.5 μm to 3 μm, and the length is 15 μm to 30 μm.

[0065] In some examples, the inorganic ceramic solid electrolyte material includes a lithium ion solid electrolyte material, a sodium ion solid electrolyte material, or a potassium ion solid electrolyte material. Further, the inorganic ceramic solid electrolyte material includes a sulfide-based solid electrolyte material.

[0066] Without limitation, the lithium ion solid electrolyte includes LISICON type solid electrolyte, NASICON type lithium ion solid electrolyte, Garnet type solid electrolyte, LIPON type solid electrolyte, Perovskite type solid electrolyte, Anti-Perovskite type lithium ion solid electrolyte, Thio-LiSICON type solid electrolyte, Li 10 GeP2S 12 One or more of a (100-e)Li2S·e(F2)·f(G2) type solid electrolyte, a (100-e)Li2S·e(F2)·f(G2) type solid electrolyte, an Argyrodite type solid electrolyte, a Halide type solid electrolyte, and a Hydride type lithium ion solid electrolyte; wherein, in the (100-e)Li2S·e(F2)·f(G2) type solid electrolyte, 20≤e≤30, 0≤f≤50, and F2 includes B2S3, Al2S3, In2S3, SiS2, GeS2 , SnS2, P2S5, As2S3, Sb2S5, Bi2S3, WS2 and MoS2, G2 includes one or more of B2O3, Al2O3, In2O3, SiO2, GeO2, SnO2, P2O5, Sb2O5, Bi2O3, WO2, WO3, MoO2, MoO3, Fe2O3, ZnO, MgO, CuO, CaO, LiN, Li2O, LiF, LiCl, LiBr and LiI.

[0067] Sodium ion solid electrolytes include NASICON type sodium ion solid electrolytes, Na-β-Alumina type solid electrolytes, Na3PS4 type solid electrolytes, Na 11 Sn2PS 12 One or more of a type solid electrolyte, an antiperovskite type solid electrolyte and a hydride type sodium ion solid electrolyte.

[0068] The potassium ion solid electrolyte includes one or more of a β-Alumina type potassium ion solid electrolyte, an Anti-Perovskite type potassium ion solid electrolyte, a K2Fe4O7 type solid electrolyte and a KSi2P3 type solid electrolyte.

[0069] As an example, the Garnet-type solid electrolyte includes Li 7-a La3Zr 2-a (A2) a O 12 ; Wherein, 0≤a<1; A2 includes one or more of Sb, Nb, Ta, Te and W.

[0070] Thio-LiSICON type solid electrolytes include Li 3+b (B2)c (C2) 1-c (D2) 4-d (E2) d ; wherein, -1 < b < 2, 0 ≤ c ≤ 1, 0 ≤ d ≤ 2; B2 includes one or more of B, Al, In, Si, Ge, Sn, Ti, W, and Mo; C2 includes one or more of P, As, Sb, and Bi; D2 includes one or more of S and Se; E2 includes one or more of F, Cl, Br, and I.

[0071] The argyrodite-type solid electrolyte includes Li 6+g (H2) h (I2) 1-h (J2) 5-i (K2) 1+i ; wherein, -1 ≤ g ≤ 1, 0 ≤ h ≤ 1, -1 < i ≤​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​, where -2 < l < 2, 0 ≤ m ≤ 2, 0 ≤ n ≤ 2, and R2 includes one or more of B, Al, In, Si, Ge, Sn, Ti, W, and Mo; S2 includes one or more of P, As, Sb, and Bi; T2 includes one or more of S and Se; U2 includes one or more of F, Cl, Br, and I.

[0077] The Halide-type solid-state electrolyte includes one or more of Li3(V2)(W2)6 and Li2Sc 2 / 3 (W2)4; where V2 includes one or more of Y, Er, In, Sc, and Ga; W2 includes one or more of F, Cl, Br, and I.

[0078] The Hydride-type lithium-ion solid-state electrolyte includes one or more of LiBH4 and pLi(CB9H 10 )·(1 - p)Li(CB 11 H 12 ); where 0 < p < 1.

[0079] The LIPON-type solid-state electrolyte includes Li x PO y N z etc.; where (2y + 3z - x = 5, x ≥ 1, y ≥ 1, z ≥ 0).

[0080] The NASICON-type sodium-ion solid-state electrolyte includes Na 1+t+2u Zr 2-u (A3) u P 3-t Si t O 12 ; where 0 ≤ t ≤ 3, 0 ≤ u ≤ 1, and A3 includes one or more of Zn, Mg, and Ca.

[0081] The Na-β-Alumina-type solid-state electrolyte includes one or more of Na2O·(5 - 7)Al2O3 and Na2O·(8 - 11)Al2O3.

[0082] The Na3PS4-type solid-state electrolyte includes Na 3+x (B3) v (C3) 1-v (D3) 4-w (E3) w , where -1 < x < 2, 0 ≤ v ≤ 1, 0 ≤ w ≤ 2, B3 includes one or more of B, Al, In, Si, Ge, Sn, Ti, W, and Mo; C3 includes one or more of P, As, Sb, and Bi; D3 includes one or more of S and Se; E3 represents one or more of F, Cl, Br, and I.

[0083] Na 11 Sn2PS 12 The Na 11+(x1) (F3) 2-y (G3) 1+y (H3) 12-z (J3) z , where -1 < x1 < 1, 0 ≤ y ≤ 2, 0 ≤ z ≤ 2, and F3 includes one or more of B, Al, In, Si, Ge, Sn, Ti, W, and Mo; G3 includes one or more of P, As, Sb, and Bi; H3 includes one or more of S and Se; J3 includes one or more of F, Cl, Br, and I.

[0084] The anti-perovskite type solid-state electrolyte includes Na3O(K3), where K3 includes one or more of Cl, Br, I, and BH4.

[0085] The Hydride type sodium-ion solid-state electrolyte includes Na2C (b1) B (a1)-(b1) H (b1) and Na(BH4) 0.5 (NH2) 0.5 , etc., where a1 = 10 or 12, and b1 = 0 or 1.

[0086] The β-alumina type potassium-ion solid-state electrolyte includes K2O·(8 - 11)Al2O3.

[0087] The Anti-Perovskite type potassium-ion solid-state electrolyte includes K3OI.

[0088] The K2Fe4O7 type solid-state electrolyte includes K2Fe4O7.

[0089] The KSi2P3 type solid-state electrolyte includes KSi2P3.

[0090] Furthermore, through the above-mentioned film layer design, the fracture toughness of the solid-state electrolyte film can be effectively improved. In some examples, the fracture toughness of the solid-state electrolyte film ≥ 0.25 MPa·m 1 / 2 . Furthermore, the fracture toughness of the solid-state electrolyte film ≥ 1.5 MPa·m 1 / 2 . Specifically, the fracture toughness of the solid-state electrolyte film includes but is not limited to: 1.67 MPa·m 1 / 2 , 2.17 MPa·m 1 / 2 , 2.37 MPa·m 1 / 2 , 2.79 MPa·m 1 / 2 , 2.83 MPa·m 1 / 2 , 2.91 MPa·m 1 / 2、3.02MPa·m 1 / 2 、3.07MPa·m 1 / 2 、3.09MPa·m 1 / 2 、3.11MPa·m 1 / 2 、3.17MPa·m 1 / 2 、3.19MPa·m 1 / 2 、3.23MPa·m 1 / 2 、3.32MPa·m 1 / 2 、3.44MPa·m 1 / 2 、3.69MPa·m 1 / 2 , 4.76MPa·m 1 / 2 , 5.32MPa·m 1 / 2 、6.231MPa·m 1 / 2 At the same time, it can be understood that the fracture toughness is related to the specific type of solid electrolyte material. In some examples of the present application, for example, when the inorganic ceramic solid electrolyte material includes a sulfide-based solid electrolyte material, the above performance can be met. However, when the solid electrolyte material is other types of materials, the fracture toughness may also be less than 0.25 MPa·m 1 / 2 However, when the solid electrolyte material used is the same, the fracture toughness of the solid electrolyte membrane can be improved by adopting the solution as exemplified above in this application.

[0091] The above-mentioned membrane design can effectively improve the critical current density of the solid electrolyte membrane. In some examples, the critical current density of the solid electrolyte membrane is ≥1.5mA / cm 2 Furthermore, the critical current density of the solid electrolyte membrane is ≥2 mA / cm 2 Specifically, the critical current density of the solid electrolyte membrane includes but is not limited to: 3.75 mA / cm 2 , 4.25mA / cm 2 , 4.50mA / cm 2 , 5.0mA / cm 2 , 5.25mA / cm 2 , 5.50mA / cm 2 , 5.75mA / cm 2 , 6.0mA / cm 2 , 6.02mA / cm 2 , 6.25mA / cm 2 , 7.25mA / cm 2At the same time, it can be understood that the critical current density is related to the specific type of solid electrolyte material. In some examples of the present application, for example, when the inorganic ceramic solid electrolyte material includes a sulfide-based solid electrolyte material, the above performance can be met. When the solid electrolyte material is other types of materials, the critical current density may also be less than 1.5 mA / cm 2 However, when the solid electrolyte material used is the same, the critical current density of the solid electrolyte membrane can be improved by adopting the solution as exemplified above in this application.

[0092] Other examples of the present application provide a method for preparing the solid electrolyte membrane as described above, comprising the following steps:

[0093] Mixing the inorganic ceramic solid electrolyte material, the phase change toughening agent and the fiber material to prepare a mixture;

[0094] The mixed material is molded to prepare the solid electrolyte membrane.

[0095] The preparation method of the solid electrolyte membrane is simple in steps and is easy to promote and apply industrially.

[0096] In some examples, the mixing is dry mixing. Furthermore, in conjunction with the dry mixing, the molding process is a pressurization process. Without limitation, the pressure of the pressurization process is 300 MPa to 600 MPa.

[0097] In some examples, the mixing is wet mixing. Furthermore, in conjunction with the wet mixing, the molding step includes coating the mixture into a film and drying. Without limitation, the solvent used in the wet mixing process includes one or more of toluene, p-xylene, o-xylene, m-xylene, trimethylbenzene, ethyl acetate, butyl butyrate, n-butyl ether, anisole, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, and n-butane.

[0098] In addition, the solid-state battery, battery module, battery pack and electrical device of the present application are described below with appropriate reference to the accompanying drawings.

[0099] In one embodiment of the present application, a solid-state battery is provided.

[0100] Typically, a solid-state battery consists of a positive electrode, a negative electrode, and an electrolyte. During the battery's charge and discharge processes, active ions are embedded in and extracted from the positive and negative electrodes. The electrolyte conducts ions between the positive and negative electrodes. Specifically, the electrolyte employs the solid electrolyte layer described above.

[0101] The positive electrode sheet includes a positive electrode current collector and a positive electrode active material layer arranged on at least one surface of the positive electrode current collector, and the positive electrode active material layer includes the positive electrode active material of the first aspect of the present application.

[0102] As an example, the positive electrode current collector has two surfaces facing each other in its thickness direction, and the positive electrode active material layer is provided on either or both of the two facing surfaces of the positive electrode current collector.

[0103] In some embodiments, the positive electrode current collector may be a metal foil or a composite current collector. For example, aluminum foil may be used as the metal foil. The composite current collector may include a polymer material base layer and a metal layer formed on at least one surface of the polymer material base layer. The composite current collector may be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material substrate (such as a substrate made of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0104] In some embodiments, the positive electrode active material may be a positive electrode active material for a battery that is well known in the art. As an example, the positive electrode active material may include at least one of the following materials: a lithium-containing phosphate with an olivine structure, a lithium transition metal oxide, and their respective modified compounds. However, the present application is not limited to these materials, and other traditional materials that can be used as positive electrode active materials for batteries may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium transition metal oxides may include, but are not limited to, lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also referred to as NCM 333 ), LiNi 0.5 Co 0.2 Mn 0.3 O2 (also referred to as NCM 523 ), LiNi 0.5 Co 0.25 Mn 0.25 O2 (also referred to as NCM 211 ), LiNi 0.6 Co 0.2 Mn 0.2 O2 (also referred to as NCM 622 ), LiNi 0.8 Co 0.1 Mn0.1 O2 (also referred to as NCM 811 ), lithium nickel cobalt aluminum oxide (such as LiNi 0.85 Co 0.15 Al 0.05 O2) and its modified compounds. Examples of olivine-structured lithium-containing phosphates may include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO4), a composite material of lithium manganese phosphate and carbon, lithium iron manganese phosphate, and a composite material of lithium iron manganese phosphate and carbon.

[0105] In some embodiments, the positive electrode active material layer may further optionally include a binder. As an example, the binder may include at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), a vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, a vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, a tetrafluoroethylene-hexafluoropropylene copolymer, and a fluorine-containing acrylate resin.

[0106] In some embodiments, the positive electrode active material layer may further include a conductive agent. For example, the conductive agent may include at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0107] In some embodiments, the positive electrode sheet can be prepared by the following method: the components for preparing the positive electrode sheet, such as the positive electrode active material, the conductive agent, the binder and any other components, are dispersed in a solvent (such as N-methylpyrrolidone) to form a positive electrode slurry; the positive electrode slurry is coated on the positive electrode collector, and after drying, cold pressing and other processes, the positive electrode sheet can be obtained.

[0108] The negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer disposed on at least one surface of the negative electrode current collector, wherein the negative electrode active material layer includes a negative electrode active material.

[0109] As an example, the negative electrode current collector has two surfaces facing each other in its thickness direction, and the negative electrode active material layer is provided on either or both of the two facing surfaces of the negative electrode current collector.

[0110] In some embodiments, the negative electrode current collector may be a metal foil or a composite current collector. For example, copper foil may be used as the metal foil. The composite current collector may include a polymer base layer and a metal layer formed on at least one surface of the polymer base layer. The composite current collector may be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer base layer (such as a base material of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0111] In some of the embodiments, the negative electrode active material may be a negative electrode active material for a battery that is well known in the art. As an example, the negative electrode active material may include at least one of the following materials: lithium metal, lithium-containing alloys, lithium-containing composites, artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate. The silicon-based material may be selected from at least one of elemental silicon, silicon oxides, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. The tin-based material may be selected from at least one of elemental tin, tin oxides, and tin alloys. However, the present application is not limited to these materials, and other traditional materials that can be used as negative electrode active materials for batteries may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0112] In some embodiments, the negative electrode active material includes one or more of lithium metal, lithium-containing alloys, and lithium-containing composites.

[0113] In some embodiments, the negative electrode active material layer may further include a binder. The binder may be selected from at least one of styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA), and carboxymethyl chitosan (CMCS).

[0114] In some embodiments, the negative electrode active material layer may further include a conductive agent, which may be selected from at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0115] In some embodiments, the negative electrode active material layer may optionally further include other additives, such as a thickener (eg, sodium carboxymethyl cellulose (CMC-Na)).

[0116] In some embodiments, the negative electrode sheet can be prepared by the following method: the components for preparing the negative electrode sheet, such as the negative electrode active material, the conductive agent, the binder and any other components, are dispersed in a solvent (such as deionized water) to form a negative electrode slurry; the negative electrode slurry is coated on the negative electrode collector, and after drying, cold pressing and other processes, the negative electrode sheet can be obtained.

[0117] In some embodiments, the positive electrode sheet, the negative electrode sheet, and the solid electrolyte membrane can be formed into an electrode assembly through a winding process or a lamination process.

[0118] In some embodiments, the solid-state battery may include an outer packaging that can be used to encapsulate the electrode assembly and the electrolyte.

[0119] In some embodiments, the outer packaging of the solid-state battery can be a hard shell, such as a hard plastic shell, an aluminum shell, a steel shell, etc. The outer packaging of the solid-state battery can also be a soft package, such as a bag-type soft package. The material of the soft package can be plastic, and examples of the plastic include polypropylene, polybutylene terephthalate, and polybutylene succinate.

[0120] The present application has no particular limitation on the shape of the solid-state battery, which can be cylindrical, square, or any other shape. For example, FIG1 shows a solid-state battery 5 having a square structure as an example.

[0121] In some embodiments, solid-state batteries can be assembled into battery modules. The number of solid-state batteries contained in the battery module can be one or more, and the specific number can be selected by those skilled in the art based on the application and capacity of the battery module.

[0122] FIG2 shows an example battery module 4. Referring to FIG2 , within the battery module 4, multiple solid-state batteries 5 may be arranged sequentially along the length of the battery module 4. Of course, they may also be arranged in any other manner. Furthermore, the multiple solid-state batteries 5 may be secured together using fasteners.

[0123] Optionally, the battery module 4 may further include a housing having a receiving space, and the plurality of solid-state batteries 5 are received in the receiving space.

[0124] In some embodiments, the battery modules may be assembled into a battery pack. The battery pack may contain one or more battery modules. The specific number may be selected by those skilled in the art based on the application and capacity of the battery pack.

[0125] Figures 3 and 4 illustrate an example battery pack 1. Referring to Figures 3 and 4 , the battery pack 1 may include a battery box and multiple battery modules 4 disposed within the battery box. The battery box comprises an upper case 2 and a lower case 3. The upper case 2 can be placed over the lower case 3 to form an enclosed space for accommodating the battery modules 4. The multiple battery modules 4 can be arranged in any manner within the battery box.

[0126] In addition, the present application also provides an electrical device, which includes at least one of the solid-state batteries, battery modules, or battery packs provided in the present application. The solid-state battery, battery module, or battery pack can be used as a power source for the electrical device, or as an energy storage unit for the electrical device. The electrical device may include, but is not limited to, mobile devices, electric vehicles, electric trains, ships and satellites, energy storage systems, etc. Among them, mobile devices may be, for example, mobile phones, laptops, etc.; electric vehicles may be, for example, pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc., but are not limited to these.

[0127] As an electrical device, solid-state batteries, battery modules or battery packs can be selected according to their usage requirements.

[0128] Figure 5 shows an example of an electric device 5. This device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle. To meet the high power and high energy density requirements of solid-state batteries, a battery pack or battery module can be used.

[0129] Another example device may be a mobile phone, a tablet computer, a laptop computer, etc. Such a device is usually required to be lightweight and thin, and may use a solid-state battery as a power source.

[0130] Below, the embodiment of the present application is described. The embodiment described below is exemplary and is only used to explain the present application, and is not to be construed as limiting the present application. Where specific techniques or conditions are not specified in the embodiments, the techniques or conditions described in the literature in this area or the product specifications are used. Reagents or instruments used that do not specify the manufacturer are conventional products that can be obtained commercially.

[0131] Example 1

[0132] (1) YSZ(D 50 =50nm), Al2O3 fibers (1μm diameter, 20μm length) and Li6PS5Cl solid electrolyte powder are mixed; wherein the volume ratio of YSZ to Li6PS5Cl solid electrolyte powder is 5%, and the volume ratio of SiO2 fibers to Li6PS5Cl solid electrolyte powder is 5%;

[0133] (2) The uniformly mixed composite solid electrolyte powder is pressed into a mold at a pressure of 500 MPa.

[0134] Specifically, when preparing the solid electrolyte membrane for testing, the uniformly mixed composite solid electrolyte powder was pressed into a 1mm thick, 5mm diameter solid electrolyte disc using a 5mm stainless steel mold at a pressure of 500MPa. A scanning electron microscope image of a cross-section of the solid electrolyte membrane prepared in Example 1 is shown in Figure 6, showing that the phase change toughening agent and the fibers formed a "reinforced concrete"-like structure.

[0135] Examples 2 to 19 and Comparative Examples 1 to 3 changed the type or volume ratio or D50 of the phase change toughening agent, the type or volume ratio or diameter*length of the fiber on the basis of Example 1. The remaining steps were the same as those in Example 1, as shown in Table 1.

[0136] Table 1

[0137] It can be seen from Table 1 that, compared with the comparative example, the embodiment can improve the mechanical properties and critical current density of the solid electrolyte membrane by combining the phase change toughening agent and the fiber material.

[0138] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are merely examples, and any embodiments having substantially the same structure and effect as the technical concept within the scope of the present application are all included in the technical scope of the present application. In addition, without departing from the scope of the present application, any other embodiments that can be conceived by those skilled in the art and that combine some of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. A solid electrolyte membrane, comprising a solid electrolyte material layer and a phase change toughening agent and a fiber material dispersed in the solid electrolyte material layer, wherein the solid electrolyte material layer comprises an inorganic ceramic solid electrolyte material.

2. The solid electrolyte membrane according to claim 1, wherein The phase change toughening agent includes ZrO2 in a metastable state; optionally, the phase change toughening agent includes one or more of yttria-stabilized zirconia, scandia-stabilized zirconia, magnesia-stabilized zirconia, calcia-stabilized zirconia and cesium oxide-stabilized zirconia.

3. The solid electrolyte membrane according to claim 1 or 2, wherein: The fiber material includes ceramic fibers; optionally, the fiber material includes one or more of silicon carbide fibers, silicon nitride fibers, boron nitride fibers, alumina fibers and silica fibers.

4. The solid electrolyte membrane according to any one of claims 1 to 3, wherein: The volume percentage of the total volume of the phase change toughening agent and the fiber material in the solid electrolyte material layer is 5% to 20%; optionally, the volume percentage is 8% to 12%.

5. The solid electrolyte membrane according to any one of claims 1 to 4, wherein: The volume ratio of the phase change toughening agent to the fiber material is 1:(0.25-4); optionally, the volume ratio is 1:(0.5-1.5).

6. The solid electrolyte membrane according to any one of claims 1 to 5, wherein: The phase change toughening agent D 50 =50nm~100nm.

7. The solid electrolyte membrane according to any one of claims 1 to 6, wherein: The fiber material has a diameter of 0.5 μm to 5 μm and a length of 10 μm to 30 μm.

8. The solid electrolyte membrane according to any one of claims 1 to 7, wherein: The inorganic ceramic solid electrolyte material includes a lithium ion solid electrolyte material, a sodium ion solid electrolyte material or a potassium ion solid electrolyte material.

9. The solid electrolyte membrane according to any one of claims 1 to 8, wherein: The solid electrolyte membrane has one or more of the following characteristics (1) to (2): (1) The fracture toughness of the solid electrolyte membrane is ≥ 0.25 MPa·m 1 / 2 ; Optionally, the fracture toughness of the solid electrolyte membrane is ≥1.5MPa·m 1 / 2 ; (2) The critical current density of the solid electrolyte membrane is ≥1.5 mA / cm 2 ; Optionally, the critical current density of the solid electrolyte membrane is ≥2mA / cm 2 .

10. The method for preparing a solid electrolyte membrane according to any one of claims 1 to 9, comprising the following steps: Mixing the inorganic ceramic solid electrolyte material, the phase change toughening agent and the fiber material to prepare a mixture; The mixed material is subjected to molding treatment to prepare the solid electrolyte membrane.

11. The method for preparing a solid electrolyte membrane according to claim 10, wherein: The mixing is dry mixing.

12. The method for preparing a solid electrolyte membrane according to claim 11, wherein: The molding process is a pressurization process; optionally, the pressure of the pressurization process is 300MPa to 600MPa.

13. The method for preparing a solid electrolyte membrane according to claim 10, wherein: The mixing is wet mixing.

14. The method for preparing a solid electrolyte membrane according to claim 13, wherein: The molding treatment step includes coating the mixture into a film, and a drying step; optionally, the solvent used in the wet mixing includes one or more of toluene, p-xylene, o-xylene, m-xylene, trimethylbenzene, ethyl acetate, butyl butyrate, n-butyl ether, anisole, ethylene glycol dimethyl ether, ethylene glycol diethyl ether and n-butane.

15. A solid-state battery comprising the solid electrolyte membrane according to any one of claims 1 to 9.

16. An electrical device comprising the solid-state battery according to claim 15.

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