Solid electrolyte, preparation method thereof, composite positive electrode active material, positive electrode plate, all-solid-state battery and electric device

Abstract

The invention discloses a solid electrolyte, a preparation method thereof, a composite positive electrode active material and an all-solid-state battery. The solid electrolyte has a core-shell structure, an inner core is a garnet type solid electrolyte, the high cubic phase purity in the crystal structure can provide more rapid lithium ion conduction channels, the high ionic conductivity of the material is ensured, meanwhile, the doped elements such as Al, Fe and Ga can stabilize the cubic phase, and the high ionic conductivity of the material can be kept for a long time; and the shell is a uniform carbon coating layer, so that the electronic conductivity of the material can be effectively improved, the material has high ionic conductivity and electronic conductivity, and the rate capability and the stability of a battery are improved. According to the preparation method of the solid electrolyte, the solid electrolyte with high ion-electron conductivity can be prepared only through one-step sintering, the preparation process is simple, the cost is low, and the performance of a final product is good.

Description

Technical Field

[0001] The present application relates to the technical field of battery materials, and particularly relates to a solid electrolyte, a preparation method thereof, a composite cathode active material, a cathode electrode sheet, a all-solid-state battery, and an electrical device. Background Art

[0002] All-solid-state batteries have been widely studied due to their higher energy density and inherent safety. However, the poor contact between the cathode active material and the solid electrolyte leads to difficult interfacial ion transport, greatly reducing the cycle performance of all-solid-state batteries. Currently, adding a solid electrolyte material to the cathode active material to form a composite cathode active material is an effective strategy to improve ion transport kinetics.

[0003] Garnet-type solid electrolytes have high ionic conductivity and chemical stability, which can improve the diffusion rate and migration rate of ions in the composite cathode active material. Therefore, they have become a very promising composite material at present. However, the garnet-type solid electrolyte has poor electronic conductivity, resulting in slow electron transfer between the cathode and the current collector, which has an adverse effect on the rate performance of the battery. Therefore, it is necessary to improve its electronic conductivity. Summary of the Invention

[0004] The first object of the present application is to provide a solid electrolyte, aiming to solve the problem that the existing garnet-type solid electrolyte has relatively low electronic conductivity to a certain extent.

[0005] The second object of the present application is to provide a preparation method of a solid electrolyte to solve the problems of complex preparation routes and limited improvement effect on electronic conductivity in the existing process.

[0006] The third object of the present application is to provide a composite cathode active material to solve the problem of large resistance of the existing materials.

[0007] In a first aspect, the present application provides a solid electrolyte, including a core and a carbon coating layer uniformly coated on the surface of the core; the core is a garnet-type solid electrolyte with a chemical general formula of Li 7-3x M x [[ID=B]]La3Zr2O 12 , 0 < x ≤ 0.3, M includes at least one of Al, Fe, and Ga elements, and the proportion of the cubic phase in the crystal structure of the core is ≥ 99.0%; based on the mass of the solid electrolyte, the content of the carbon coating layer is 0.5% - 5%; the electronic conductivity of the solid electrolyte at 25°C is ≥ 2.0×10 -5 S·cm -1 .

[0008] In an optional embodiment, the thickness of the carbon coating layer is 0.5 nm - 10 nm.

[0009] In one alternative embodiment, the thickness of the carbon coating layer is 1 nm to 8 nm.

[0010] In one optional embodiment, the particle size Dv50 of the solid electrolyte is 0.05 μm-6 μm.

[0011] In one optional embodiment, the particle size Dv50 of the solid electrolyte is 0.1 μm-5 μm.

[0012] In one optional embodiment, the particle size dispersion coefficient δ of the solid electrolyte satisfies: 0.15≤δ≤0.25 and δ=Dv10 / Dv65, where Dv10 refers to the particle size corresponding to the cumulative volume distribution percentage of the solid electrolyte reaching 10%, and Dv65 refers to the particle size corresponding to the cumulative volume distribution percentage of the solid electrolyte reaching 65%.

[0013] In one optional embodiment, the solid electrolyte has an ionic conductivity ≥ 4.0 × 10⁻⁶ at 25°C. - 4 S·cm -1 .

[0014] Secondly, this application provides a method for preparing the solid electrolyte described in the first aspect, comprising the following steps:

[0015] S1. Disperse lithium source, dopant, lanthanum source, zirconium source, organic carbon source and inorganic carbon source in deionized water to form a slurry, and spray dry the slurry to obtain a spray material;

[0016] S2. The spray material is subjected to sintering treatment by first heating it to 380℃-420℃ and holding it for a first time, then heating it to 850℃-900℃ and holding it for a second time, and then continuing to heat it to 1150℃-1250℃ and holding it for a third time to obtain the calcined material.

[0017] In one optional embodiment, the sintering is carried out in an inert atmosphere, with the inert protective gas flow rate being 1.5 L / min to 3 L / min, and the inert protective gas being selected from at least one of nitrogen, argon, and helium.

[0018] In one alternative embodiment, the temperature is increased to 380°C-420°C at a rate of 2°C / min-5°C / min.

[0019] In one alternative implementation, the first time is 3h-5h.

[0020] In one alternative embodiment, the temperature is increased to 850°C-900°C at a rate of 1°C / min-3°C / min.

[0021] In one alternative implementation, the second time is 7h-10h.

[0022] In one alternative embodiment, the temperature is increased to 1150℃-1250℃ at a rate of 1℃ / min-3℃ / min.

[0023] In one alternative implementation, the third time is 7h-10h.

[0024] In one optional embodiment, the spray drying process conditions include: using nitrogen as the drying heat source, controlling the inlet air temperature to be 180℃-240℃, the exhaust air temperature to be 80℃-150℃, and the feed rate to be 0.5L / h-5L / h.

[0025] In one optional embodiment, S1 involves sand milling the slurry before spray drying, including: the solid content of the slurry is 15wt%-45wt%, the sand mill speed is 500rpm-2000rpm, the particle size of the sand mill beads is 0.2mm-0.5mm, the sand milling time is 0.5h-3h, and the particle size Dv50 of the sand-milled material is controlled at 100nm-500nm.

[0026] In one optional embodiment, the molar ratio of lithium in the lithium source to lanthanum in the lanthanum source, zirconium in the zirconium source, and M in the dopant is y:3:2:x, where 0 <x≤0.3,1.05≤y / (7-3x)≤1.3。

[0027] In one optional embodiment, the amount of organic carbon source and inorganic carbon source added is such that the mass percentage of carbon in the solid electrolyte reaches 0.5%-5%, and the mass ratio of organic carbon source to inorganic carbon source is 6:1-1:2.

[0028] In one optional embodiment, the slurry further includes a dispersant, the mass of which accounts for 0.1%-2% of the slurry mass.

[0029] In one alternative embodiment, the dispersant is selected from at least one of PEG and PVP.

[0030] In an optional embodiment, S2 further includes sequentially cooling and pulverizing the calcined material.

[0031] In one alternative implementation, the cooling rate is 100°C / h to 150°C / h.

[0032] In one optional embodiment, the process conditions for pulverizing using an air jet mill include: pulverizing air pressure of 2.5MPa-5.5MPa, feeding frequency of 5Hz-15Hz, and classifier frequency of 2000rpm-6000rpm.

[0033] Thirdly, this application provides a composite positive electrode active material, comprising a ternary material and the solid electrolyte described in the first aspect or a solid electrolyte prepared by the preparation method described in the second aspect; the particle size Dv50 ratio of the ternary material to the solid electrolyte is 4.0-6.0, and the mass ratio of the ternary material to the solid electrolyte is 75-85:10-20.

[0034] In one optional embodiment, the ternary material has the general chemical formula LiNi. 1-a-b Co a Mn b O2, where 0 <a≤0.2,0<b≤0.4。

[0035] Fourthly, this application also provides a positive electrode sheet, comprising:

[0036] A positive current collector and a positive active material layer disposed on at least one side of the positive current collector, the positive active material layer comprising the composite positive active material described in the third aspect.

[0037] In one optional embodiment, the compaction density of the positive electrode sheet is greater than 3.5 g / cm³. 3 .

[0038] Fifthly, this application provides an all-solid-state battery, including the positive electrode sheet described in the fourth aspect.

[0039] In one alternative embodiment, the all-solid-state battery has a resistance of less than 140Ω at 25°C.

[0040] Sixthly, this application provides an electrical device including the all-solid-state battery described in the fifth aspect.

[0041] The technical solution of this application has the following advantages:

[0042] The solid electrolyte provided in this application has a core-shell structure. The core is a garnet-type solid electrolyte, and the high purity of the cubic phase in its crystal structure can provide more fast lithium-ion conduction channels, ensuring the high ionic conductivity of the material. At the same time, the doping elements can stabilize the cubic phase, enabling the material to maintain high ionic conductivity for a long time. Furthermore, the outer shell is a uniform carbon coating layer, which can effectively improve the electronic conductivity of the material. Thus, the material has both high ionic conductivity and electronic conductivity, which is beneficial to improving the rate performance and stability of the battery.

[0043] Additional aspects and advantages of the embodiments of this application will be described and shown in part in the following description, or illustrated by practice of the embodiments of this application. Attached Figure Description

[0044] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0045] Figure 1 This is a SEM image of the finished material 1 obtained in Example 1 of this application.

[0046] Figure 2 This is the XRD pattern of the finished material 1 obtained in Example 1 of this application. Detailed Implementation

[0047] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0048] 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.

[0049] In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0050] 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.

[0051] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a specific parameter, it is also expected that ranges of 60-110 and 80-120 are also included. Furthermore, if minimum range values ​​1 and 2 are listed, and if maximum range values ​​3, 4, and 5 are listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this application, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this article; "0-5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0052] 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, or B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0053] Currently, to address the poor electronic conductivity of garnet-type solid electrolytes, a common modification strategy is elemental doping. However, single-element doping has limited effect on improving electronic conductivity, while multi-element doping can lead to significant distortion of the crystal structure, reducing ionic conductivity and affecting lithium-ion transport between the cathode and current collector. Alternatively, blending the solid electrolyte with a conductive agent can also improve its electronic conductivity, but this method involves two steps: the synthesis of the solid electrolyte and the blending with the conductive agent. This process is complex and costly, and ensuring uniform mixing is difficult, potentially leading to localized aggregation of the conductive agent and ultimately poor results.

[0054] To address the problems existing in the aforementioned related technologies, according to a first aspect of this application, this application provides a solid electrolyte, comprising a core and a carbon coating layer uniformly covering the surface of the core; the core is a garnet-type solid electrolyte with the chemical formula Li. 7-3x M x La3Zr2O 12, M includes at least one of Al, Fe, and Ga elements, 0 < x ≤ 0.3, and the proportion of the cubic phase in the crystal structure of the core is ≥ 99.0%; based on the mass of the solid electrolyte, the content of the carbon coating layer is 0.5% - 5%; the electronic conductivity of the solid electrolyte at 25°C is ≥ 2.0×10 -5 S·cm -1 .

[0055] The solid electrolyte provided by this application has a core-shell structure. The core is a garnet-type solid electrolyte, and the high cubic-phase purity in its crystal structure can provide more rapid lithium-ion conduction channels, ensuring high ionic conductivity of the material. At the same time, doping elements such as Al, Fe, and Ga can also stabilize the cubic phase, enabling the material to maintain high ionic conductivity for a long time; and the outer shell is a uniformly coated carbon layer, which can effectively improve the electronic conductivity of the material, so that the material has both high ionic conductivity and electronic conductivity, which is beneficial to improving the rate performance and stability of the battery. The applicant's research found that when the content of the carbon coating layer is within the range of 0.5% - 5%, it can improve the conductivity of the material without affecting the transport of lithium ions. If the content of the carbon coating layer is too high, it will cause the carbon layer to be too thick and affect the transport of lithium ions. On the contrary, if the content of the carbon coating layer is too low, it will lead to the inability to form a uniform and dense carbon layer, and the conductivity improvement effect is not good. As an example, the content of the carbon coating layer can be, for example, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, etc. or within the range composed of any of the above values.

[0056] It can be understood that the thickness of the carbon coating layer will also affect the coating and modification effects. The applicant's research found that when the thickness of the carbon coating layer is within the range of 0.5 nm - 10 nm, a uniform and dense carbon layer can be formed, improving the conductivity without affecting the transport of lithium ions. If the carbon coating layer is too thick, it will cause difficulties in lithium-ion transport. On the contrary, if the carbon coating layer is too thin, it is easy to break during the charge and discharge process, resulting in a decrease in conductivity. As an example, the thickness of the carbon coating layer can be, for example, 0.5 nm, 1 nm, 2 nm, 3 nm, 4 nm, 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, etc. or within the range composed of any of the above values.

[0057] The applicant's research found that the particle size of the solid electrolyte is closely related to its mechanical stability, ionic conductivity, electrochemical performance, etc. In some embodiments of this application, the particle size Dv50 of the solid electrolyte is within the range of 0.05 μm - 6 μm, thereby ensuring relatively high ionic conductivity. As an example, the ionic conductivity of the solid electrolyte in this application at 25°C is ≥ 4.0×10 -4 S·cm -1This facilitates lithium-ion diffusion. If the particle size of the solid electrolyte is too large, the lithium-ion diffusion path will be longer, affecting the battery's rate performance. Conversely, if the particle size of the solid electrolyte is too small, there will be too many grain boundaries. At the same time, the ionic conductivity of the solid electrolyte at the grain boundaries is much lower than that in the bulk phase, thereby reducing the ionic conductivity of the material. As an example, the particle size of the solid electrolyte can be 0.05 μm, 0.1 μm, 0.5 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, etc., or within any range of the above values.

[0058] Furthermore, the particle size distribution of the solid electrolyte also affects its electrochemical performance. This application defines the particle size dispersion coefficient of the solid electrolyte as δ = Dv10 / Dv65, where Dv10 refers to the particle size corresponding to a cumulative volume distribution percentage of 10% for the solid electrolyte, and Dv65 refers to the particle size corresponding to a cumulative volume distribution percentage of 65% for the solid electrolyte. The applicant's research has found that when δ is in the range of 0.15-0.25, the solid electrolyte itself can produce a particle gradation effect, with a higher filling rate of small particles, thus increasing the compaction density of the material. If the δ value is too large or too small, it will lead to a decrease in the filling rate and a lower compaction density of the material. As an example, the particle size dispersion coefficient δ of the solid electrolyte can be, for example, 0.15, 0.18, 0.20, 0.22, 0.25, or any value within the range of these values.

[0059] According to a second aspect of this application, a method for preparing a solid electrolyte is provided, comprising the following steps:

[0060] S1. Disperse lithium source, dopant, lanthanum source, zirconium source, organic carbon source and inorganic carbon source in deionized water to form a slurry, and spray dry the slurry to obtain a spray material;

[0061] S2. The spray material is subjected to sintering treatment by first heating it to 380℃-420℃ and holding it for a first time, then heating it to 850℃-900℃ and holding it for a second time, and then continuing to heat it to 1150℃-1250℃ and holding it for a third time to obtain the calcined material.

[0062] The preparation method provided in this application utilizes an aqueous medium to uniformly mix all raw materials, followed by spray drying to obtain spherical sprayable particles with good flowability. A subsequent sintering process is then performed. By controlling the sintering process conditions within the range of 380℃-420℃ (e.g., 380℃, 390℃, 400℃, 410℃, 420℃, or any combination thereof), the organic carbon source is first melted and fully wetted into the precursor. During the subsequent sintering process, the organic carbon source decomposes to form a uniform carbon layer. This carbon layer adheres better to the precursor surface and allows the inorganic carbon source to uniformly coat the carbon layer, ultimately forming a uniformly coated carbon layer. This effectively improves the electronic conductivity of the solid electrolyte. The process involves heating the precursor to 850℃-900℃ (e.g., 850℃, 860℃, 870℃, 880℃, 890℃, 900℃, or any range thereof) to induce a reaction and form a crystal structure dominated by a low-temperature cubic phase. However, this structure has limited effect on improving ionic conductivity. Therefore, this application further increases the sintering temperature to transform the low-temperature cubic phase into a tetragonal phase, and then at 1150℃-1250℃ (e.g., 1150℃, 1180℃, 1200℃, 1220℃, 1250℃, or any range thereof) to transform it into a high-temperature cubic phase, thereby effectively improving the ionic conductivity of the solid electrolyte. Therefore, the preparation method of this application only requires one sintering step to obtain a solid electrolyte with high ionic-electron conductivity. The preparation process is simple, low-cost, and the final product has good performance.

[0063] It should be noted that inorganic carbon can provide more graphitic carbon, contributing more to improving the electronic conductivity of the material, but inorganic carbon is more expensive and cannot be uniformly coated. On the other hand, the decomposed carbon from organic carbon sources has a larger specific surface area and lower compaction density, which can affect the energy density of the battery when combined with the positive electrode active material. Simultaneously, the decomposed carbon from organic carbon sources can better adhere to the precursor, preventing excessively large particle sizes. Therefore, this application combines inorganic and organic carbon sources to improve coating uniformity and, while maintaining the same electronic conductivity, reduce the particle size of the solid electrolyte, thereby increasing the energy density of the composite positive electrode active material. In some embodiments of this application, the mass ratio of organic carbon source to inorganic carbon source is 6:1 to 1:2, thus balancing electronic conductivity and carbon layer coating uniformity. For example, the mass ratio of organic carbon source to inorganic carbon source can be, for example, 6:1, 5:1, 4:1, 3:1, 2:1, 1:1, 1:2, or any range of these values. In some embodiments, the organic carbon source may be at least one of glucose, sucrose, cyclodextrin, and starch, and the inorganic carbon source may be at least one of acetylene black, Ketjen black, and graphene.

[0064] It is understood that the lithium source, dopant, lanthanum source, and zirconium source in this application are all water-insoluble substances. For example, the dopant can be aluminum oxide, Al(OH)3, gallium trioxide, Ga(OH)3, ferric oxide, Fe(OH)3, or Fe2(C2O4)3, the lanthanum source is lanthanum oxide, the zirconium source is zirconium oxide, and the lithium source is lithium carbonate.

[0065] In one optional embodiment, the sintering step in S2 is carried out in an inert atmosphere, with the inert protective gas flow rate being 1.5 L / min to 3 L / min. This stabilizes the gas field and makes the reaction more stable. As an example, the inert protective gas flow rate can be 1.5 L / min, 1.75 L / min, 2 L / min, 2.25 L / min, 2.5 L / min, 2.75 L / min, 3 L / min, or any range thereof. The inert protective gas is selected from at least one of nitrogen, argon, and helium.

[0066] Understandably, using a slow heating method in the S2 sintering step ensures uniform heating of the material, preventing unstable and uneven reactions. Specifically, in some embodiments, the temperature can be initially raised to 380℃-420℃ at a rate of 2℃ / min-5℃ / min and held for 3-5 hours to allow the organic carbon source to fully decompose and combine with inorganic carbon to form a uniform carbon coating layer. Then, the temperature is raised to 850℃-900℃ at a rate of 1℃ / min-3℃ / min and held for 7-10 hours to allow the precursor to react and form a low-temperature cubic phase structure of garnet-type solid electrolyte. Finally, the temperature is raised to 1150℃-1250℃ at a rate of 1℃ / min-3℃ / min and held for 7-10 hours to transform the crystal structure into a cubic phase with high ionic conductivity, thereby ensuring high ionic conductivity of the material.

[0067] In this application, during the preparation of the slurry in step S1, a dispersant is added to improve the uniformity of dispersion of the precursor raw materials and carbon source in water. The mass of the dispersant accounts for 0.1%-2% of the slurry mass. As an example, the mass of the dispersant may be 0.1%, 0.3%, 0.6%, 0.9%, 1.2%, 1.4%, 1.6%, 1.8%, 2%, or any range thereof, of the slurry mass. In some embodiments, the dispersant may be at least one of PEG and PVP.

[0068] To ensure the uniformity of the spray material composition, in this application, the slurry is subjected to sanding treatment before the spray drying step in S1, specifically including: the solid content of the slurry is 15wt%-45wt%, the rotational speed of the sand mill is 500rpm-2000rpm, the particle size of the sanding beads is 0.2mm-0.5mm, the sanding time is 0.5h-3h, and the particle size Dv50 of the material after sanding is controlled within 100nm-500nm. Thus, the particle size and distribution of the final product can be controlled.

[0069] In an optional embodiment, the process conditions for the spray drying include: using nitrogen as the drying heat source, controlling the inlet air temperature to be 180°C-240°C, the outlet air temperature to be 80°C-150°C, and the feeding speed to be 0.5L / h-5L / h. Thus, the stability of the inlet air temperature and the outlet air temperature can be ensured.

[0070] In an optional embodiment, the molar ratio of lithium element in the lithium source, lanthanum element in the lanthanum source, zirconium element in the zirconium source, and M element in the dopant is y:3:2:x, where 0<x≤0.3 and 1.05≤y / (7-3x)≤1.3. This ratio can compensate for the volatilization loss of the lithium source during high-temperature sintering.

[0071] It can be understood that in S2, cooling and pulverization treatment are also included for the calcined material. In some embodiments, the cooling rate is 100°C / h-150°C / h, thereby avoiding particle defect cracks caused by too fast cooling rate. As an example, the cooling rate can be, for example, 100°C / h, 110°C / h, 120°C / h, 130°C / h, 140°C / h, 150°C / h, etc. or within the range composed of any of the above values. In an optional embodiment, a jet mill is used for pulverization treatment, specifically including: the pulverizing gas pressure is 2.5MPa-5.5MPa, the feeding frequency is 5Hz-15Hz, and the frequency of the classifier is 2000rpm-6000rpm; thus, the particle size of the pulverized material can be reasonably controlled.

[0072] According to the third aspect of this application, this application also provides a composite cathode active material, including a ternary material and the solid electrolyte described in the first aspect or the solid electrolyte prepared by using the preparation method described in the second aspect; the ratio of the particle size Dv50 of the ternary material to the solid electrolyte is 4.0-6.0, and the mass ratio of the ternary material to the solid electrolyte is 75-85:10-20.

[0073] By means of the particle size distribution with a specific mass and particle size ratio, the compaction density of the positive electrode sheet can be increased, and at the same time, the high ion-electron conductivity of the solid electrolyte also endows the positive electrode sheet with a low resistance. As an example, the ratio of the particle size Dv50 of the ternary material to the solid electrolyte can be, for example, 4.0, 4.25, 4.5, 4.75, 5.0, 5.25, 5.5, 5.75, 6.0, etc. or within the range composed of any of the above values, and the mass ratio of the ternary material to the solid electrolyte can be, for example, 75:20, 77:15, 80:13, 82:12, 85:10, etc. or within the range composed of any of the above values.

[0074] In some embodiments, the chemical general formula of the ternary material is LiNi 1-a-b Co a Mn b O2, where 0 < a ≤ 0.2 and 0 < b ≤ 0.4. As an example, the ternary material can be LiNi 0.5 Co 0.3 Mn 0.2 O2 (abbreviated as NCM532), LiNi 0.6 Co 0.2 Mn 0.2 O2 (abbreviated as NCM622), LiNi 0.8 Co 0.1 Mn 0.1 O2 (abbreviated as NCM811).

[0075] According to the fourth aspect of the present application, the present application provides a positive electrode sheet, including a positive electrode current collector and a positive electrode active material layer provided on at least one side of the positive electrode current collector, and the positive electrode active material layer includes the composite positive electrode active material described in the third aspect.

[0076] In some embodiments, the compaction density of the positive electrode sheet is greater than 3.5 g / cm 3 . Those skilled in the art can understand that the positive electrode sheet of the present application has the advantages of high compaction density and small resistance, which is beneficial to improving the capacity, rate performance and cycle performance of the battery.

[0077] According to the fifth aspect of the present application, the present application provides a all-solid-state battery, including the positive electrode sheet described in the fourth aspect of the present application.

[0078] In some embodiments, the resistance of the all-solid-state battery at 25 °C is less than 140 Ω. It should be noted that the resistance is the total resistance measured by an impedance analyzer (EIS) and is the total resistance of an equivalent circuit composed of ohmic internal resistance, interfacial impedance and charge transfer resistance.

[0079] Those skilled in the art will understand that the all-solid-state battery of this application has the advantages of large capacity, good rate and cycle performance, and high safety.

[0080] According to a sixth aspect of this application, this application provides an electrical device including the all-solid-state battery described in the fifth aspect of this application.

[0081] In some embodiments, the aforementioned electrical device may also include a battery module or battery pack assembled from the all-solid-state battery. The all-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 (e.g., mobile phones, laptops, etc.), electric vehicles (e.g., pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc.

[0082] As for the aforementioned electrical devices, solid-state batteries, battery modules, or battery packs can be selected according to their usage requirements. As an example, an electrical device could be 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 for these devices, battery packs or battery modules can be used. Another example device could be a mobile phone, tablet computer, or laptop computer. These devices typically require a thin and light design and can use solid-state batteries as their power source.

[0083] The present application will be further described in detail below with reference to specific embodiments, which should not be construed as limiting the scope of protection claimed in the present application.

[0084] It should be noted that the industry standard formula for calculating solid content is generally: Solid content = (Mass of all solids / Total mass of solids and water) * 100%, without considering the case where solids dissolve in water. The solid electrolyte layer Li6PS5Cl used in the embodiments and comparative examples of this application was purchased from Guangdong Zhuguang New Energy Technology Co., Ltd., model number MA-EN-SS-0030.

[0085] Example 1

[0086] This embodiment provides a method for preparing an all-solid-state battery, including the following steps:

[0087] (1) Preparation and characterization of solid electrolytes

[0088] According to the molar ratio of Li:La:Zr:Al = 7.68:3:2:0.2, 275.62 g of lithium carbonate, 475.06 g of lanthanum oxide, 239.41 g of zirconium oxide, and 9.91 g of aluminum oxide were weighed and dispersed in 2500 g of deionized water. Simultaneously, 35 g of glucose, 15 g of Ketjen Black, and 30 g of PEG were added, resulting in a slurry with a solid content of 30.2%. The mixed slurry was transferred to a sand mill, and the mill speed was set to 1100 rpm. The particle size of the zirconium oxide grinding beads was 0.35 mm. After continuous sand milling for 1.5 h, a sample was taken for testing, and the particle size Dv50 was found to be 250 nm. Sand milling was then stopped, and the slurry was poured out to obtain the abrasive.

[0089] Pour the abrasive into the feed tank of the spray dryer, turn on the nitrogen valve, set the inlet air temperature of the spray dryer to 200℃ and the outlet air temperature to 120℃, and wait for the temperature to stabilize. Then start spray drying at a feed rate of 2L / h. After all the abrasive has dried, remove the sprayed material from the outlet.

[0090] The sprayed material was placed in a magnesium oxide crucible and then placed in a box furnace for high-temperature sintering. The sintering atmosphere was nitrogen with a gas flow rate of 2.5 L / min. The temperature was increased to 400℃ at a rate of 3℃ / min and held for 4 hours. Then, the temperature was increased to 870℃ at a rate of 2℃ / min and held for 9 hours. The temperature was then increased to 1200℃ and held for 9 hours. Finally, the material was cooled to room temperature at a rate of 150℃ / h to obtain the sintered material.

[0091] The sintered material was pulverized using an air jet mill. The feeding frequency was set to 10 Hz, the grading parameter was set to 3500 rpm, and the pulverizing air pressure was 3.5 MPa. After pulverization, the solid electrolyte finished product 1 was obtained.

[0092] The chemical formula of the finished product 1 obtained in this embodiment is Li 6.4 La3Zr2Al 0.2 O7, its SEM image is as follows Figure 1 As shown in the figure, the particle sizes of finished material 1 are as follows: Dv50 is 1.83 μm, Dv10 is 0.52 μm, Dv65 is 2.88 μm, and the particle size dispersion coefficient δ = 0.181. The thickness of the outer carbon layer is 4.6 nm, and the carbon layer content accounts for 2.74% of the total material mass. XRD test results are as follows... Figure 2 As shown, the XRD pattern was refined, and the results showed that the cubic phase accounted for 99.42% of the finished product 1. The ionic conductivity and electronic conductivity of the finished product 1 were tested, and the results are shown in Table 2, which are 6.4 × 10⁻⁶. -4 S·cm -1 and 4.2×10 -5 S·cm -1 .

[0093] (2) Fabrication and testing of all-solid-state batteries

[0094] NCM811 (Dv50 of 9.18 μm), finished product 1, conductive carbon black, and polyvinylidene fluoride (PVDF) were added to a high-energy ball mill at a mass ratio of 80:15:2:3 and mixed at 800 rpm for 30 min. The uniformly mixed powder was dispersed in polyvinylpyrrolidone (NMP) to obtain a slurry. The slurry was coated onto a carbon-coated aluminum foil current collector, and after drying and rolling, composite positive electrode 1 was obtained. The compacted density of electrode 1 was tested to be 3.54 g / cm³. 3 Electrode 1 was assembled with a thin lithium sheet and a solid electrolyte layer of Li6PS5Cl to form an all-solid-state battery 1. The battery resistance was 125Ω, the 1C / 0.1C capacity ratio was 80%, and the capacity retention rate after 100 cycles at 1C was 89.7%. The results are shown in Table 3.

[0095] Example 2

[0096] This embodiment provides a method for preparing an all-solid-state battery, including the following steps:

[0097] (1) Preparation and characterization of solid electrolytes

[0098] According to the molar ratio of Li:La:Zr:Al = 7.02:3:2:0.3, 267.99 g of lithium carbonate, 476.81 g of lanthanum oxide, 240.29 g of zirconium oxide, and 14.91 g of aluminum oxide were weighed and dispersed in 4000 g of deionized water. Simultaneously, 40 g of glucose, 10 g of Ketjen Black, and 25 g of PEG were added, resulting in a slurry with a solid content of 21.2%. The mixed slurry was transferred to a sand mill, and the mill speed was set to 1800 rpm. The zirconium oxide grinding beads had a particle size of 0.25 mm. After continuous sand milling for 2 hours, a sample was taken for testing, and the particle size Dv50 was found to be 200 nm. Sand milling was then stopped, and the slurry was poured out to obtain sand material 2.

[0099] Pour the abrasive 2 into the feed tank of the spray dryer, turn on the nitrogen valve, set the inlet air temperature of the spray dryer to 190℃ and the outlet air temperature to 100℃, and wait for the temperature to stabilize. Then start spray drying at a feed rate of 4L / h. After all the abrasive 2 has dried, remove the spray material 2 from the outlet.

[0100] The spray material 2 was placed in a magnesium oxide crucible and then placed in a box furnace for high-temperature sintering. The sintering atmosphere was nitrogen with a gas flow rate of 3 L / min. The temperature was increased to 380°C at a rate of 5°C / min and held for 3.5 h. Then, the temperature was increased to 860°C at a rate of 3°C / min and held for 8 h. The temperature was then increased to 1180°C and held for 8 h. Finally, the temperature was cooled to room temperature at a rate of 150°C / h to obtain sintered material 2.

[0101] The sintered material 2 was pulverized using an air jet mill. The feeding frequency was set to 8 Hz, the grading parameter was set to 4500 rpm, and the pulverizing air pressure was 4.5 MPa. After pulverization, the solid electrolyte finished product 2 was obtained.

[0102] The chemical formula of the finished product 2 obtained in this embodiment is Li. 6.1 La3Zr2Al 0.3 O7, after testing, the particle size of finished material 2 was found to be Dv50 of 1.12 μm, Dv10 of 0.45 μm, and Dv65 of 2.29 μm, with a particle size dispersion coefficient δ = 0.197. The thickness of the outer carbon layer was 1.9 nm, and the carbon layer content accounted for 1.63% of the total material mass. The XRD pattern of finished material 2 was refined, showing a cubic phase content of 99.14%. The ionic conductivity and electronic conductivity of finished material 2 were tested, and the results are shown in Table 2, which are 5.9 × 10⁻⁶ and 5.9 × 10⁻⁶, respectively. -4 S·cm -1 and 2.8×10 -5 S·cm -1 .

[0103] (2) Fabrication and testing of all-solid-state batteries

[0104] NCM811 (Dv50 of 5.44μm), finished product 2, conductive carbon black, and PVDF were added to a high-energy ball mill at a mass ratio of 75:20:3:2 and mixed at 800 rpm for 30 min. The uniformly mixed powder was dispersed in NMP to obtain a slurry. The slurry was coated onto a carbon-coated aluminum foil current collector, and after drying and rolling, composite positive electrode 2 was obtained. The compacted density of electrode 2 was tested to be 3.52 g / cm³. 3 Electrode 2 was assembled with a thin lithium sheet and a solid electrolyte layer of Li6PS5Cl to form an all-solid-state battery 2. The battery resistance was 131Ω, the 1C / 0.1C capacity ratio was 84%, and the capacity retention rate after 100 cycles at 1C was 92.5%. The results are shown in Table 3.

[0105] Example 3

[0106] This embodiment provides a method for preparing an all-solid-state battery, including the following steps:

[0107] (1) Preparation and characterization of solid electrolytes

[0108] According to the molar ratio of Li:La:Zr:Al = 7.86:3:2:0.15, 280.96 g of lithium carbonate, 473.17 g of lanthanum oxide, 238.46 g of zirconium oxide, and 7.40 g of aluminum oxide were weighed and dispersed in 1600 g of deionized water. Simultaneously, 25 g of glucose, 25 g of Ketjen Black, and 40 g of PEG were added, resulting in a slurry with a solid content of 40.5%. The mixed slurry was transferred to a sand mill, and the mill speed was set to 800 rpm. The zirconium oxide grinding beads had a particle size of 0.4 mm. After continuous sand milling for 0.5 h, a sample was taken for testing, and the particle size Dv50 was found to be 330 nm. Sand milling was then stopped, and the slurry was poured out to obtain abrasive material 3.

[0109] Pour the abrasive 3 into the feed tank of the spray dryer, turn on the nitrogen valve, set the inlet air temperature of the spray dryer to 225℃ and the outlet air temperature to 135℃, and wait for the temperature to stabilize. Then start spray drying at a feed rate of 1L / h. After all the abrasive is dried, remove the spray material 3 from the outlet.

[0110] The spray material 3 was placed in a magnesium oxide crucible and then placed in a box furnace for high-temperature sintering. The sintering atmosphere was nitrogen with a gas flow rate of 1.5 L / min. The temperature was increased to 410°C at a heating rate of 2°C / min and held for 3.5 h. Then, the temperature was increased to 880°C at a heating rate of 1.5°C / min and held for 10 h. The temperature was then increased to 1230°C and held for 10 h. Finally, the temperature was cooled to room temperature at a cooling rate of 150°C / h to obtain sintered material 3.

[0111] The sintered material 3 was pulverized using an air jet mill. The feeding frequency was set to 13 Hz, the grading parameter was set to 2500 rpm, and the pulverizing air pressure was 3 MPa. After pulverization, carbon-coated solid electrolyte finished product 3 was obtained.

[0112] The chemical formula of the finished product 3 obtained in this embodiment is Li. 6.55 La3Zr2Al 0.15 O7, after testing, the particle size of finished material 3 was found to be Dv50 of 3.85 μm, Dv10 of 1.03 μm, and Dv65 of 4.89 μm, with a particle size dispersion coefficient δ = 0.211. Its outer carbon layer thickness was 1.2 nm, and the carbon layer content accounted for 4.31% of the total material mass. The XRD pattern of finished material 3 was refined, showing a cubic phase content of 99.86%. The ionic conductivity and electronic conductivity of finished material 3 were tested, and the results are shown in Table 2, which are 8.5 × 10⁻⁶ and 8.5 × 10⁻⁶, respectively. -4 S·cm -1 and 7.6×10 -5 S·cm -1 .

[0113] (2) Fabrication and testing of all-solid-state batteries

[0114] NCM811 (Dv50 of 17.26μm), finished product 3, conductive carbon black, and PVDF were added to a high-energy ball mill at a mass ratio of 85:11:1.5:2.5 and mixed at 800 rpm for 30 min. The uniformly mixed powder was dispersed in NMP to obtain a slurry. The slurry was coated onto a carbon-coated aluminum foil current collector, and after drying and rolling, composite positive electrode 3 was obtained. The compacted density of electrode 3 was tested to be 3.61 g / cm³. 3 Electrode 3 was assembled with thin lithium sheet and solid electrolyte layer Li6PS5Cl to form all-solid-state battery 3. The battery resistance was 116Ω, the 1C / 0.1C capacity ratio was 78%, and the capacity retention rate after 100 cycles at 1C was 90.8%. The results are shown in Table 3.

[0115] Examples 4-11 and Comparative Examples 1-6 were prepared using the same method as in Example 1, with differences shown in Table 1.

[0116] Table 1. Preparation process parameters for each embodiment and comparative example.

[0117]

[0118]

[0119] Test case

[0120] 1. XRD test

[0121] The XRD diffractometer was a Bruker D8 Advance, and the Highscore software was used to refine the XRD patterns after testing (Rietvald method). The specific refinement method was as follows: First, the default settings were used and automatic fitting was performed. Then, the cubic phase, tetragonal phase, and impurity phase La2Zr2O7 phase cards of the garnet-type solid electrolyte were imported. The inserted phases, peak shapes, pattern parameters, structural parameters, etc., were refined and analyzed manually, and the proportion of each phase was recorded.

[0122] 2. Particle size test

[0123] Particle sizes Dv10, Dv50, and Dv65 were determined using a laser particle size analyzer (Malvern Master Size 2000) in accordance with standard GB / T19077-2016 / ISO 13320:2009.

[0124] 3. Compacted density test

[0125] A powder compaction density meter was used, and the test pressure was 3T.

[0126] 4. Ionic conductivity test

[0127] Ionic conductivity was tested by AC impedance spectroscopy. First, the material was pressed into tablets using a powder compaction density meter at a pressure of 50 kN and a thickness of 1 mm. Then, a symmetrical cell of blocking electrode / electrolyte / blocking electrode was constructed. The impedance spectrum of the cell was tested using a Chenhua CHI600E instrument. The ionic conductivity of the material (25℃) was calculated based on the impedance spectrum.

[0128] 5. Electronic conductivity test

[0129] The electronic conductivity was tested using the dual-blocking electrode DC polarization method. First, the powder was pressed into tablets to construct a symmetrical cell of blocking electrode / electrolyte / blocking electrode. The cell was brought to a steady state by applying voltage for a long time, at which point lithium ions did not migrate. The electronic conductivity of the material (25℃) could then be calculated based on the current value measured by the instrument.

[0130] 6. Battery impedance test

[0131] Electrochemical impedance spectroscopy (EIS) measurements of the prepared cells were performed using an impedance analyzer in the frequency range of 0.001 Hz to 1 MHz (25 °C).

[0132] 7. Electrochemical testing of all-solid-state batteries

[0133] Button battery test method: The rate performance and cycle performance were tested using the CT2001A charge-discharge instrument of Wuhan Landian. Test conditions: nominal specific capacity of 200mAh / g, test voltage of 2.7-4.3V.

[0134] The test results are shown in Tables 2-3.

[0135] Table 2. Physicochemical parameters of each embodiment and comparative example.

[0136]

[0137] Table 3. Battery Composition and Performance Indicators

[0138]

[0139]

[0140] As can be seen from Tables 1-3, the cubic phase purity of the solid electrolytes prepared in Examples 1-11 is above 99.0%, the carbon coating content is between 0.5% and 5%, and the ionic conductivity and electronic conductivity are both above 4.0 × 10⁻⁶. -4 S·cm -1 and 2.0×10 -5 S·cm -1 The compaction density of the composite cathode formed after gradation with NCM811 is all around 3.5 g / cm³. 3The assembled all-solid-state battery exhibits a resistance of less than 140Ω, a capacity ratio of over 75% at 1C / 0.1C, and a retention rate of over 85% after 100 cycles at 1C. This demonstrates that by employing a one-step sintering method to introduce a carbon coating layer in situ and optimizing the sintering process, this application can prepare a solid electrolyte material with high ionic-electronic conductivity, thereby increasing the compaction density of the composite cathode and reducing battery resistance. In Comparative Example 1, the amount of solid electrolyte was too small, resulting in a low compaction density of the composite cathode. In Comparative Example 2, the lack of carbon coating resulted in poor electronic conductivity of the solid electrolyte material, leading to excessive battery resistance. In Comparative Example 3, the sintering temperature was too low, resulting in low purity of the cubic phase in the solid electrolyte and excessive battery resistance. In Comparative Example 4, the δ value of the solid electrolyte material was too large, resulting in poor particle size distribution and low electrode compaction density. In Comparative Example 5, the carbon coating layer content was too large, leading to difficulty in lithium-ion transport and low ionic conductivity. In Comparative Example 6, the particle size of the solid electrolyte material was too large, resulting in a longer lithium-ion diffusion path, decreased ionic conductivity, and excessive battery resistance.

[0141] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this application.

Claims

1. A solid electrolyte, comprising a core and a carbon coating layer uniformly covering the surface of the core; characterized in that, The core is a garnet-type solid electrolyte with a chemical general formula of Li 7-3x M x La3Zr2O 12 , M includes at least one of Al, Fe, and Ga elements, 0 < x ≤ 0.3, and the proportion of the cubic phase in the crystal structure of the core is ≥ 99.0%; based on the mass of the solid electrolyte, the content of the carbon coating layer is 0.5% - 5%; the electronic conductivity of the solid electrolyte at 25°C is ≥ 2.0×10 -5 S·cm -1 .

2. The solid electrolyte according to claim 1, characterized in that, The thickness of the carbon coating layer is 0.5 nm to 10 nm; And / or, the particle size Dv50 of the solid electrolyte is 0.05 μm-6 μm; And / or, the particle size dispersion coefficient δ of the solid electrolyte satisfies: 0.15≤δ≤0.25 and δ=Dv10 / Dv65, where Dv10 refers to the particle size corresponding to the cumulative volume distribution percentage of the solid electrolyte reaching 10%, and Dv65 refers to the particle size corresponding to the cumulative volume distribution percentage of the solid electrolyte reaching 65%. And / or, the solid electrolyte has an ionic conductivity ≥ 4.0 × 10⁻⁶ at 25 °C. -4 S·cm -1 .

3. The solid electrolyte according to claim 1 or 2, characterized in that, The thickness of the carbon coating layer is 1nm-8nm; And / or, the particle size Dv50 of the solid electrolyte is 0.1 μm-5 μm.

4. A method for preparing a solid electrolyte according to any one of claims 1-3, characterized in that, Includes the following steps: S1. Disperse lithium source, dopant, lanthanum source, zirconium source, organic carbon source and inorganic carbon source in deionized water to form a slurry, and spray dry the slurry to obtain a spray material; S2. The spray material is subjected to sintering treatment by first heating it to 380℃-420℃ and holding it for a first time, then heating it to 850℃-900℃ and holding it for a second time, and then continuing to heat it to 1150℃-1250℃ and holding it for a third time to obtain the calcined material.

5. The method for preparing a solid electrolyte according to claim 4, characterized in that, The sintering is carried out in an inert atmosphere, with the inert protective gas flow rate being 1.5 L / min to 3 L / min; the inert protective gas is selected from at least one of nitrogen, argon, and helium. And / or, increase the temperature to 380℃-420℃ at a rate of 2℃ / min-5℃ / min; And / or, the first time is 3h-5h; And / or, increase the temperature to 850℃-900℃ at a rate of 1℃ / min-3℃ / min; And / or, the second time is 7h-10h; And / or, increase the temperature to 1150℃-1250℃ at a rate of 1℃ / min-3℃ / min; And / or, the third time is 7h-10h.

6. The method for preparing a solid electrolyte according to claim 4 or 5, characterized in that, The spray drying process conditions include: using nitrogen as the drying heat source, controlling the inlet air temperature at 180℃-240℃, the exhaust air temperature at 80℃-150℃, and the feed rate at 0.5L / h-5L / h. And / or, S1 first performs a sand milling treatment on the slurry before spray drying, including: the solid content of the slurry is 15wt%-45wt%, the sand mill speed is 500rpm-2000rpm, the particle size of the sand mill beads is 0.2mm-0.5mm, the sand milling time is 0.5h-3h, and the particle size Dv50 of the material after sand milling is controlled at 100nm-500nm; And / or, the molar ratio of lithium in the lithium source to lanthanum in the lanthanum source, zirconium in the zirconium source, and M in the dopant is y:3:2:x, where 0 <x≤0.3,1.05≤y / (7-3x)≤1.3; And / or, the amount of organic carbon source and inorganic carbon source added is such that the mass percentage of carbon in the solid electrolyte reaches 0.5%-5%, and the mass ratio of organic carbon source to inorganic carbon source is 6:1-1:2; And / or, the slurry further includes a dispersant, the dispersant accounting for 0.1%-2% of the slurry mass; optionally, the dispersant is selected from at least one of PEG and PVP; And / or, S2 further includes sequentially cooling and pulverizing the calcined material; optionally, the cooling rate is 100℃ / h-150℃ / h; optionally, the process conditions for pulverizing using an air jet mill include: pulverizing air pressure of 2.5MPa-5.5MPa, feeding frequency of 5Hz-15Hz, and classifier frequency of 2000rpm-6000rpm.

7. A composite positive electrode active material, characterized in that, The invention includes a ternary material and a solid electrolyte as described in any one of claims 1-3 or a solid electrolyte prepared by any one of claims 4-6; the particle size Dv50 ratio of the ternary material to the solid electrolyte is 4.0-6.0, and the mass ratio of the ternary material to the solid electrolyte is 75-85:10-20. Optionally, the general chemical formula of the ternary material is LiNi. 1-a-b Co a Mn b O2, where 0 <a≤0.2,0<b≤0.4。 8. A positive electrode sheet, characterized in that, include: A positive current collector and a positive active material layer disposed on at least one side of the positive current collector, wherein the positive active material layer comprises the composite positive active material as described in claim 7; Optionally, the compaction density of the positive electrode sheet is greater than 3.5 g / cm³. 3 .

9. An all-solid-state battery, characterized in that, Includes the positive electrode sheet as described in claim 8; Optionally, the resistance of the all-solid-state battery at 25°C is less than 140Ω.

10. An electrical device, characterized in that, Including the all-solid-state battery as described in claim 11.

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