Solid electrolytes, solid-state batteries, and electrical devices.

Abstract

Invention details;

Description

Solid electrolytes, solid-state batteries and electrical equipment

[0001] Priority information

[0002] This disclosure claims priority to the Chinese patent disclosure with patent application number 202211742332.8, filed with the State Intellectual Property Office of China on December 30, 2022, and disclosed in the name of “Solid-state electrolytes, solid-state batteries and electrical equipment”, the entire contents of which are incorporated by reference in this disclosure. Technical Field

[0003] The present disclosure relates to the field of battery technology, and in particular to solid-state electrolytes, solid-state batteries, and electrical equipment. Background Art

[0004] The development of sulfide-based all-solid-state batteries has attracted widespread attention in the industry due to their high ionic conductivity, low grain boundary resistance, and non-flammability. However, sulfide solid-state electrolytes have a high reduction potential (around 1.7V), which can lead to interfacial reactions on the negative electrode side. The resulting interfacial layer has poor ion transport capacity, increasing interfacial resistance and ultimately causing battery failure.

[0005] Public content

[0006] In view of this, the present disclosure provides a solid electrolyte that, when applied to a solid-state battery, can lower the interfacial ionic impedance between the solid-state electrolyte and the negative electrode, thereby optimizing the performance of the solid-state battery.

[0007] Specifically, a first aspect of the present disclosure provides a solid electrolyte, including a first solid electrolyte layer and a second solid electrolyte layer, wherein the first solid electrolyte layer includes a first sulfide solid electrolyte, and the second solid electrolyte layer includes a phosphide solid electrolyte.

[0008] When the solid-state electrolyte disclosed herein is applied to a solid-state battery and the second solid-state electrolyte layer is arranged adjacent to the negative electrode, the interface layer between the solid-state electrolyte and the negative electrode can contain more high-ionic conductivity components, which can effectively reduce the interface impedance while maintaining the overall electronic conductivity of the solid-state electrolyte at a low level, thereby optimizing the performance of the solid-state battery.

[0009] In a second aspect, the present disclosure provides a solid-state battery comprising a positive electrode, a negative electrode and a solid-state electrolyte as described in the first aspect, wherein the solid-state electrolyte is arranged between the positive electrode and the negative electrode, the first solid-state electrolyte layer is arranged between the positive electrode and the second solid-state electrolyte layer, and the second solid-state electrolyte layer is arranged between the first solid-state electrolyte layer and the negative electrode.

[0010] In a third aspect, the present disclosure provides an electrical device comprising the solid-state battery as described in the second aspect.

[0011] Public detailed description

[0012] The following will be combined with the accompanying drawings in the embodiments of the present disclosure to clearly and completely describe the technical solutions in the embodiments of the present disclosure. Obviously, the embodiments described are only part of the embodiments of the present disclosure, not all of the embodiments. Based on the embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present disclosure.

[0013] Since sulfide solid electrolytes have the characteristics of high ionic conductivity, low grain boundary impedance and non-flammability, the development of sulfide all-solid-state batteries has received widespread attention in the industry. However, the electrochemical window of sulfide solid electrolytes is narrow. On the negative electrode side, due to the high reduction potential of sulfide solid electrolytes (about 1.7V), there is a problem of interfacial reaction, especially when used with high energy density negative electrodes such as lithium metal and some lithium alloys, the interface ion impedance will increase dramatically. In order to reduce the interface ion impedance between the negative electrode and optimize the performance of solid-state batteries, the present disclosure provides a solid electrolyte, including a first solid electrolyte layer and a second solid electrolyte layer, the first solid electrolyte layer including a first sulfide solid electrolyte, and the second solid electrolyte layer including a phosphide solid electrolyte. The solid electrolyte provided by the present disclosure, when applied to a solid-state battery, can be arranged between the positive electrode and the negative electrode, wherein the first solid electrolyte layer is arranged adjacent to the positive electrode, and the second solid electrolyte layer is arranged adjacent to the negative electrode. Since the second solid electrolyte layer includes a phosphide solid electrolyte with a lower reduction potential, the stability of the interface between the solid electrolyte and the negative electrode is improved. At the same time, the phosphide solid electrolyte in the second solid electrolyte layer can make the interface layer between the solid electrolyte and the negative electrode contain more high ionic conductivity components (such as Li3P, etc.), which can effectively reduce the interface ion impedance between the solid electrolyte and the negative electrode. At the same time, the first sulfide solid electrolyte in the first solid electrolyte layer can maintain the electronic conductivity of the solid electrolyte itself at a low level. Therefore, the solid electrolyte of the present disclosure can effectively reduce the interface ion impedance between the solid electrolyte and the negative electrode while maintaining the electronic conductivity of the solid electrolyte itself at a low level, thereby optimizing the charge and discharge performance and cycle performance of the solid-state battery.

[0014] In the embodiment of the present disclosure, the first sulfide solid electrolyte can be a known sulfide solid electrolyte. For example, the first sulfide solid electrolyte can be selected from one or more of a fast ion conductor type sulfide solid electrolyte, a thiogermanite type sulfide solid electrolyte, a glass ceramic type sulfide solid electrolyte, a thiophosphate system sulfide solid electrolyte, and a thiosilicate system sulfide solid electrolyte, but is not limited thereto. For example, the fast ion conductor type sulfide solid electrolyte can be Li3PS4, Li 10 GeP2S 12 、Li 9.54 Si 1.74 P 1.44 S 11.7 Cl 0.3 One or more of; Argentatite-type sulfide solid electrolyte can be Li 6-z PS 5-z Cl 1+z (0≤z≤1), etc.; the glass ceramic sulfide solid electrolyte can be LiI-(70Li2S-30P2S5), etc.; the thiophosphate system sulfide solid electrolyte can be Li7P3S 11 , Li4PS4I, and Li7P2S8I; the sulfide solid electrolyte of the thiosilicate system may be Li2SiS3 or the like. The phosphide solid electrolyte may be a phosphorus-containing compound having a certain ionic conductivity, for example, a room temperature ionic conductivity of 0.01 mS / cm or higher.

[0015] In some embodiments of the present disclosure, the phosphide solid electrolyte contains a phosphorus element with a valence of -3. The phosphorus element in the phosphide solid electrolyte may be entirely or partially -3. The inclusion of a phosphorus element with a valence of -3 in the phosphide solid electrolyte can improve the conductivity of the interface layer between the solid electrolyte and the negative electrode, thereby further improving the charge-discharge performance and cycling performance of the solid-state battery.

[0016] In some embodiments of the present disclosure, the reduction potential of the phosphide solid electrolyte is 0 to 1.2 V. When the reduction potential of the phosphide solid electrolyte is within this range, the electrochemical stability of the solid electrolyte to the negative electrode is higher, the interfacial side reactions are weaker, and the formed interfacial layer is thinner, which can further improve the stability of the interface between the solid electrolyte and the negative electrode, reduce the interfacial ionic impedance, and improve the charge and discharge performance and cycle life of the solid-state battery.

[0017] In some embodiments of the present disclosure, the above-mentioned phosphide solid electrolyte is Li 3x-3 AP x He Li 3y-4 BP yAt least one of the elements, the P element has a valence of -3, the A element is selected from at least one of Al, Ga and In, the B element is selected from at least one of Si, Ge and Sn, x is an integer between 2 and 4, and y is an integer between 2 and 6.

[0018] In some embodiments of the present disclosure, the above-mentioned phosphide solid electrolyte includes Li9AlP4, Li9GaP4, Li9InP4, Li3AlP2, Li3GaP2, Li3InP2, Li8SiP4, Li8GeP4, Li8SnP4, Li2SiP2, Li2GeP2, Li2SnP2, Li 14 SiP6 and Li 14 In some embodiments of the present disclosure, the above-mentioned phosphide solid electrolyte includes Li9AlP4, Li9GaP4, Li 14 SiP6 and Li 14 At least one of GeP6, the room temperature ionic conductivity of these phosphide solid electrolytes is in the order of mS / cm, which helps to further improve the conductivity of the solid electrolyte, thereby optimizing the charge and discharge performance and cycle performance of the battery.

[0019] In some embodiments of the present disclosure, the first sulfide solid electrolyte is selected from Li3PS4, Li 10 GeP2S 12 (LGPS), Li 9.54 Si 1.74 P 1.44 S 11.7 Cl 0.3 、Li 6-z PS 5-z Cl 1+z , LiI-(70Li2S-30P2S5), Li7P3S 11 , Li4PS4I, Li7P2S8I, Li2SiS3 one or more; the Li 6-z PS 5-z Cl 1+z In the equation ( ), z ranges from 0 ≤ z ≤ 1. These sulfide solid electrolytes have relatively high ionic conductivity and relatively low electronic conductivity, and are well compatible with phosphide solid electrolytes, which helps improve the electrochemical performance of solid-state batteries.

[0020] In some embodiments of the present disclosure, the content of the first sulfide solid electrolyte in the first solid electrolyte layer is 90 wt.% to 99.9 wt.%, based on the total mass of the first solid electrolyte layer. For example, the content of the first sulfide solid electrolyte in the first solid electrolyte layer can be 90 wt.%, 92 wt.%, 94 wt.%, 96 wt.%, 98 wt.%, or 9.9 wt.%. When the content of the first sulfide solid electrolyte in the first solid electrolyte layer is within this range, the ion transport capability of the solid electrolyte can be improved while maintaining its structural stability, thereby enhancing the charge-discharge performance and cycling performance of the solid-state battery.

[0021] In some embodiments of the present disclosure, the content of the phosphide solid electrolyte in the second solid electrolyte layer is 90 wt.% to 99.9 wt.%, based on the total mass of the second solid electrolyte layer. When the content of the phosphide solid electrolyte in the second solid electrolyte layer is within this range, the interfacial ionic resistance between the solid electrolyte and the negative electrode can be further reduced, thereby optimizing battery performance.

[0022] In some embodiments of the present disclosure, the second solid electrolyte layer further includes a second sulfide solid electrolyte. That is, the second solid electrolyte layer includes a second sulfide solid electrolyte and a phosphide solid electrolyte. The types of the first sulfide solid electrolyte and the second sulfide solid electrolyte may be the same or different, and the first sulfide solid electrolyte and the second sulfide solid electrolyte may each independently be a known sulfide solid electrolyte. For example, the second sulfide solid electrolyte may be selected from one or more of a fast ion conductor type sulfide solid electrolyte, a silver germanium sulfide solid electrolyte, a glass ceramic type sulfide solid electrolyte, a thiophosphate system sulfide solid electrolyte and a thiosilicate system sulfide solid electrolyte, but is not limited thereto. Specifically, the fast ion conductor type sulfide solid electrolyte may be Li3PS4, LGPS, Li 9.54 Si 1.74 P 1.44 S 11.7 Cl 0.3 One or more of; Argentatite-type sulfide solid electrolyte can be Li 6-z PS 5-z Cl 1+z (the value range of z is 0≤x≤1), etc.; the glass ceramic sulfide solid electrolyte can be LiI-(70Li2S-30P2S5), etc.; the thiophosphate system sulfide solid electrolyte can be Li7P3S 11 , one or more of Li4PS4I and Li7P2S8I; the sulfide solid electrolyte of the sulfosilicate system can be Li2SiS3, etc.

[0023] In some embodiments of the present disclosure, the content of the second sulfide solid electrolyte and the phosphide solid electrolyte in the second solid electrolyte layer is 90 wt.% to 99.9 wt.%, based on the total mass of the second solid electrolyte layer. In other words, the sum of the content of the second sulfide solid electrolyte and the phosphide solid electrolyte in the second solid electrolyte layer is 90 wt.% to 99.9 wt.%.

[0024] In some embodiments of the present disclosure, the first solid electrolyte layer and the second solid electrolyte layer also contain a binder. Based on the total mass of the first solid electrolyte layer, the content of the binder in the first solid electrolyte layer is 0.1wt.% to 10wt.%. Based on the total mass of the second solid electrolyte layer, the content of the binder in the second solid electrolyte layer is 0.1wt.% to 10wt.%. Based on the total mass of the solid electrolyte, the content of the binder in the solid electrolyte is 0.1wt.% to 10wt.%. The presence of a binder can improve the structural stability of the solid electrolyte. The binder in the solid electrolyte can be selected from one or more of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), styrene-butadiene rubber (SBR), nitrile rubber (NBR), polyacrylate, polyacrylic acid (PAA), alkyl cellulose and polyethylene oxide (PEO).

[0025] In some embodiments of the present disclosure, based on the total mass of the second sulfide solid electrolyte and the phosphide solid electrolyte in the second solid electrolyte layer, the content of the second sulfide solid electrolyte in the second solid electrolyte layer is 10 wt.% to 95 wt.%, and the content of the phosphide solid electrolyte is 5 wt.% to 90 wt.%. In other words, the mass of the second sulfide solid electrolyte accounts for 10 wt.% to 95 wt.% of the total mass of the second sulfide solid electrolyte and the phosphide solid electrolyte in the second solid electrolyte layer, and the mass of the phosphide solid electrolyte accounts for 5 wt.% to 90 wt.%. For example, in the second solid electrolyte layer, the content of the second sulfide solid electrolyte can be 10 wt.%, 20 wt.%, 30 wt.%, 40 wt.%, 50 wt.%, 60 wt.%, 70 wt.%, 80 wt.%, 90 wt.%, or 95 wt.%, and the content of the phosphide solid electrolyte can be 5 wt.%, 10 wt.%, 20 wt.%, 30 wt.%, 40 wt.%, 50 wt.%, 60 wt.%, 70 wt.%, 80 wt.%, or 90 wt.%. When these content ranges are met, the solid electrolyte can improve the interfacial stability with the negative electrode, reduce the interface layer impedance with the negative electrode, while maintaining low electronic conductivity, thereby improving the capacity and cycle life of the solid-state battery.

[0026] In some embodiments of the present disclosure, based on the total mass of the second sulfide solid electrolyte and the phosphide solid electrolyte in the second solid electrolyte layer, the content of the second sulfide solid electrolyte in the second solid electrolyte layer is 30 wt.% to 70 wt.%, and the content of the phosphide solid electrolyte is 30 wt.% to 70 wt.%. When these content ranges are met, the solid electrolyte can have both low electronic conductivity and low interface impedance with the negative electrode, thereby improving the capacity and cycle life of the solid-state battery.

[0027] In some embodiments of the present disclosure, the thickness of the first solid electrolyte layer is 15 μm to 200 μm; the thickness of the second solid electrolyte layer is 1 μm to 15 μm. For example, the thickness of the first solid electrolyte layer can be 20 μm, 40 μm, 60 μm, 80 μm, 100 μm, 120 μm, 140 μm, 160 μm, 180 μm or 200 μm; the thickness of the second solid electrolyte layer can be 1 μm, 3 μm, 5 μm, 7 μm, 9 μm, 11 μm, 13 μm or 15 μm. Meeting this thickness range can make the solid electrolyte have good interfacial stability with the negative electrode while maintaining low electronic conductivity, thereby improving the electrochemical performance of the solid-state battery.

[0028] In some embodiments of the present disclosure, the thickness of the first solid electrolyte layer is 15 μm to 50 μm; the thickness of the second solid electrolyte layer is 3 μm to 7 μm. Meeting this thickness range can further improve the interfacial stability between the solid electrolyte and the negative electrode while maintaining low electronic conductivity, thereby improving the electrochemical performance of the solid-state battery.

[0029] In some embodiments of the present disclosure, the D50 of the first sulfide solid electrolyte is 1 to 10 μm; the D50 of the second sulfide solid electrolyte is 0.5 to 4 μm; and the D50 of the phosphide solid electrolyte is 0.5 to 4 μm. For example, the D50 of the first sulfide solid electrolyte can be 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, or 10 μm; the D50 of the second sulfide solid electrolyte can be 0.5 μm, 1 μm, 2 μm, 3 μm, or 4 μm; and the D50 of the phosphide solid electrolyte can be 0.5 μm, 1 μm, 2 μm, 3 μm, or 4 μm. When the D50 of the first sulfide solid electrolyte, the second sulfide solid electrolyte, and the phosphide solid electrolyte are controlled within the above range, the density of the solid electrolyte can be improved and the ionic conductivity of the solid electrolyte can be improved.

[0030] In some embodiments of the present disclosure, the D50 of the first sulfide solid electrolyte is 2 to 5 μm, the D50 of the second sulfide solid electrolyte is 0.7 to 2 μm, and the D50 of the phosphide solid electrolyte is 0.7 to 2 μm. When the D50 of the first sulfide solid electrolyte, the second sulfide solid electrolyte, and the phosphide solid electrolyte are controlled within the above ranges, the density and ionic conductivity of the solid electrolyte can be further improved.

[0031] The present disclosure also provides a solid-state battery, which includes a positive electrode, a negative electrode and the above-mentioned solid electrolyte, the solid electrolyte is arranged between the positive electrode and the negative electrode, the first solid electrolyte layer is arranged between the positive electrode and the second solid electrolyte layer, and the second solid electrolyte layer is arranged between the first solid electrolyte layer and the negative electrode.

[0032] In the solid-state battery disclosed herein, the phosphide solid electrolyte has a lower reduction potential than the sulfide solid electrolyte. Therefore, a second solid-state electrolyte layer containing a phosphide solid electrolyte is provided on the side close to the negative electrode, which can improve the electrochemical stability of the solid electrolyte to the negative electrode, weaken the interface side reaction between the solid electrolyte and the negative electrode, and make the formed interface layer thinner, thereby effectively reducing the interface ion impedance and optimizing the solid-state battery performance. At the same time, the first sulfide solid electrolyte in the first solid electrolyte layer can maintain the electronic conductivity of the solid electrolyte itself at a low level. Therefore, the solid-state electrolyte disclosed herein.

[0033] In the embodiments of the present disclosure, the solid-state battery may be an all-solid-state battery or a semi-solid-state battery.

[0034] In the embodiment of the present disclosure, the positive electrode may include a positive electrode current collector and a positive electrode material layer provided on at least one side of the positive electrode current collector. The positive electrode current collector may include but is not limited to metal film materials, foam metal mesh, etc., specifically aluminum foil, carbon-coated aluminum foil, etc. The positive electrode material layer may include positive electrode active materials, solid electrolyte materials, conductive agents, binders, etc. Based on the weight of the positive electrode material layer, the content of the positive electrode active material is 50wt.% to 85wt.%, the content of the solid electrolyte is 5wt.% to 49wt.%, the content of the binder is 0.1wt.% to 10wt.%; and the content of the conductive agent is 0-10wt.%. The positive electrode active material may be selected from known positive electrode active materials for secondary batteries, such as materials that can reversibly extract and insert lithium ions, including but not limited to olivine-based positive electrode active materials (such as LiFePO4, etc.), layered oxide-based positive electrode active materials (such as ternary materials NCM, NCA, lithium cobalt oxide LiCoO2, etc.), spinel positive electrode active materials (such as LiMn2O4, Li4Ti5O 12etc.), sulfur and sulfide cathode materials (such as S8, FeS2, CuS, etc.). The solid electrolyte material can be selected from known sulfide solid electrolytes and halide solid electrolytes. For example, the sulfide solid electrolyte can be selected from Li3PS4, LGPS, Li 9.54 Si 1.74 P 1.44 S 11.7 Cl 0.3 、Li 6-z PS 5-z Cl 1+z , LiI-(70Li2S-30P2S5), Li7P3S 11 , Li4PS4I, Li7P2S8I, Li2SiS3, etc. The halide solid electrolyte can be selected from Li3InCl6, Li3YCl6, etc. The binder can be selected from binders commonly used in positive electrodes, including but not limited to one or more of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), styrene-butadiene rubber (SBR), nitrile rubber (NBR), polyacrylate, polyacrylic acid (PAA), alkyl cellulose, and polyethylene oxide (PEO). The conductive agent is selected from commonly used conductive agents for positive electrodes, such as acetylene black, carbon nanotubes, carbon fibers, and carbon black.

[0035] In the embodiment of the present disclosure, the negative electrode can be selected from known negative electrodes for secondary batteries, for example, the negative electrode is selected from lithium foil, lithium alloy foil, copper foil with metallic lithium attached, stainless steel foil with metallic lithium attached, copper foil with lithium alloy attached, stainless steel foil with lithium alloy attached, etc., and the lithium alloy can be selected from one or more of lithium indium alloy, lithium silicon alloy, lithium boron alloy, lithium tin alloy, lithium magnesium alloy, lithium aluminum alloy, lithium silver alloy and silicon-based negative electrode.

[0036] In some embodiments of the present disclosure, after the first charge and discharge of the solid-state battery, an interface layer is formed between the second solid electrolyte layer and the negative electrode, and the interface layer contains Li3P. The room temperature ionic conductivity of Li3P is 10 -4 S / cm, with high ionic conductivity, can make the interface layer have high ionic conductivity, reduce the overall impedance of the solid-state battery, and improve the performance of the solid-state battery. The composition of the interface layer can be analyzed by XPS combined with nuclear magnetic resonance.

[0037] In some embodiments of the present disclosure, the Li3P content in the interface layer is 5 wt.% to 25 wt.%, based on the mass of the interface layer. Li3P within this range can further improve the ionic conductivity of the interface layer, reduce the overall impedance of the solid-state battery, and provide the interface layer with a more stable structure. This also prevents excessive Li3P content from leading to excessive electronic conductivity in the interface layer, thereby preventing the interface layer from becoming too thick and causing excessive impedance due to continued reaction between the negative electrode and the electrolyte, which could affect battery performance.

[0038] In some embodiments of the present disclosure, the interface layer further comprises Li2S, Li2S a 、M1 b P and M2 c S; M1 and M2 are independently selected from one or more of Si, Ge, Sn, Al, Ga and In, and the value ranges of a, b and c are 2≤a≤8, 0.75≤b≤1.5, and 0.5≤c≤1. The interface layer also includes Li2S, Li2S a 、M1 b P and M2 c When the second sulfide solid electrolyte contains a halogen X element, the interface layer also contains a LiX component, wherein X is selected from F, Cl, Br or I. Among these interface layer components, Li2S, Li2S a The presence of LiX can maintain the electronic conductivity of the interface layer at a low level to avoid the negative electrode from continuously reducing the electrolyte, resulting in an excessively high thickness of the interface layer and an excessively large interface ion impedance; M1 b P and M2 c S can inhibit the formation of dendritic lithium to a certain extent, which is beneficial to improving the battery cycle stability.

[0039] In some embodiments of the present disclosure, the negative electrode comprises metallic lithium or a lithium alloy. Such a negative electrode has a high lithium insertion capacity, thereby enabling the solid-state battery to have a high energy density.

[0040] In some embodiments of the present disclosure, the method for preparing the solid-state battery includes the following steps:

[0041] (1) The positive electrode is prepared by wet coating or dry extrusion; the wet coating method can be to disperse the positive electrode active material, solid electrolyte material, conductive agent and binder in a solvent to obtain a positive electrode slurry, coat the positive electrode slurry on the positive electrode collector, and obtain the positive electrode after drying, rolling and cutting. The positive electrode includes a positive electrode collector and a positive electrode material layer; the solvent is selected from medium and low polarity solvents, and the medium and low polarity solvent can be selected from one or more of methylcyclohexane, heptane, decane, anisole, cyclopentane ether, toluene, xylene, butyl butyrate and methyl benzoate; the dry extrusion method can be to mix the positive electrode active material, solid electrolyte material, conductive agent and binder uniformly and then extrude to form a positive electrode material layer.

[0042] (2) The first sulfide solid electrolyte and the binder are mixed and coated, stacked or transferred to the surface of the positive electrode material layer to form a first solid electrolyte layer; the binder in the first solid electrolyte layer can be selected from one or more of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), styrene-butadiene rubber (SBR), nitrile rubber (NBR), polyacrylate, polyacrylic acid (PAA), alkyl cellulose and polyethylene oxide (PEO). Among them, coating refers to first directly coating the electrolyte slurry prepared by dispersing the solid electrolyte and the binder in the solvent onto the surface of the positive electrode material layer, and then forming a solid electrolyte layer directly on the positive electrode surface after drying and rolling; stacking refers to coating the electrolyte slurry on the PET film by wet coating, and then peeling it off by rolling to form a self-supporting electrolyte membrane or directly preparing a self-supporting electrolyte membrane by dry extrusion of the solid electrolyte and the binder, and then stacking the self-supporting electrolyte membrane on the positive electrode sheet and combining them together by a certain pressure; transfer refers to rolling the electrolyte layer wet-coated on the PET film and the positive electrode sheet relative to each other to transfer the electrolyte layer from the PET film to the surface of the positive electrode layer.

[0043] (3) The phosphide solid electrolyte and the binder are mixed and then coated, stacked, or transferred onto the surface of the first solid electrolyte layer to form a second solid electrolyte layer; the binder in the second solid electrolyte layer can be selected from one or more of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), styrene-butadiene rubber (SBR), nitrile rubber (NBR), polyacrylate, polyacrylic acid (PAA), alkyl cellulose, and polyethylene oxide (PEO). When the second electrolyte layer contains a second sulfide solid electrolyte, the second sulfide solid electrolyte, the phosphide solid electrolyte, and the binder can be mixed and then coated, stacked, or transferred onto the surface of the first solid electrolyte layer to form a second solid electrolyte layer.

[0044] (4) Pressing the negative electrode sheet onto the second solid electrolyte layer to obtain an all-solid-state battery.

[0045] The present disclosure also provides an electrical device comprising the aforementioned solid-state battery. The electrical device may be a vehicle, an energy storage power station, or an electronic device. The vehicle may be a pure electric vehicle or a hybrid electric vehicle; the electronic device may be a consumer electronics product.

[0046] The embodiments of the present disclosure are further described below with reference to a number of specific embodiments.

[0047] Example 1

[0048] (1) Preparation of phosphide solid electrolyte:

[0049] In a glove box, accurately weigh 5 g of lithium metal powder, aluminum powder, and red phosphorus powder according to the stoichiometric ratio of Li9AlP4 and place them in a zirconia-lined ball mill. Zirconia balls are placed in the mill, maintaining a ball-to-bearing ratio of 25:1. Mill the mixture in a high-speed ball mill at 1000 RPM for 18 hours. Cool the mill with cooling water throughout the milling process to maintain a temperature of 15 ± 5°C. After milling, remove the powder.

[0050] The powder is pressed into a block using a cold press, sealed in an ampoule, and sintered in a muffle furnace at 800°C for 24 hours. The sintered electrolyte sheet is ground into powder to obtain the corresponding Li9AlP4 solid electrolyte.

[0051] (2) Preparation of solid-state batteries:

[0052] All the following steps are completed in a drying room with a dew point below -50°C.

[0053] Step 1: 75g LiNi 0.6 Mn 0.2 Co 0.2 O2 (NCM622) positive electrode material, 20g of solid electrolyte Li6PS5Cl, 3g of nitrile rubber binder, and 2g of acetylene black were added to 100g of xylene solvent and stirred in a vacuum mixer to form a stable, uniform positive electrode slurry. This positive electrode slurry was evenly and intermittently coated on both sides of aluminum foil (160mm wide, 16μm thick), then dried at 373K. After being rolled on a roller press, a single-sided 80μm thick positive electrode material layer was formed on both sides of the aluminum foil to produce a positive electrode sheet.

[0054] Step 2: 58.2g of Li6PS5Cl and 1.8g of nitrile rubber binder were placed in 60g of xylene solution and stirred thoroughly until a stable, uniform slurry was formed. This solution was continuously coated onto the positive electrode sheet and then dried at 373K to form a positive electrode sheet-first solid electrolyte layer composite. The first solid electrolyte layer had a thickness of 50μm. In Step 2, the D50 of Li6PS5Cl was 4μm.

[0055] Step 3: A mixed powder of 1.746g of Li9AlP4 and 4.074g of Li6PS5Cl and 0.18g of a nitrile rubber binder were placed in 6g of a xylene solution and stirred thoroughly until a stable, uniform slurry was formed. This solution was then continuously coated onto the first solid electrolyte layer of the positive electrode sheet-first solid electrolyte layer composite, followed by drying at 373K to form a positive electrode sheet-first solid electrolyte layer-second solid electrolyte layer composite. The second solid electrolyte layer had a thickness of 5μm.

[0056] In step 3, the D50 of Li6PS5Cl is 1 μm, and the D50 of Li9AlP4 is 1 μm.

[0057] Step 4: Cut the positive electrode sheet-first solid electrolyte layer-second solid electrolyte layer composite layer into a positive electrode sheet-first solid electrolyte layer-second solid electrolyte layer composite membrane with a length×width size of 21 mm×41 mm.

[0058] Step 5: Select a lithium-copper composite foil (i.e., copper foil with metallic lithium attached) as the negative electrode, with a lithium layer thickness of 15 μm, and cut it into a 20 mm × 40 mm negative electrode film.

[0059] Step 6: Align the positive electrode sheet-first solid electrolyte layer-second solid electrolyte layer composite membrane obtained in Step 4 and the negative electrode membrane obtained in Step 5 and place them in a hot press. Press at 453K for 1 hour and a pressure of 200 MPa. Vacuum seal with aluminum-plastic film and remove the sample. Finally, press the pressed sample in an isostatic press at 200 MPa for 300 seconds to obtain the solid-state battery of this example, designated C1.

[0060] Example 2

[0061] (1) Preparation of phosphide solid electrolyte: In a glove box, 5 g of lithium metal powder, gallium powder, and red phosphorus powder were accurately weighed according to the stoichiometric ratio of Li9GaP4 and placed in a zirconia-lined ball mill. Zirconia ball milling beads were placed in the ball mill to control the ball-to-material ratio to 25:1. The mixture was ball milled in a high-speed ball mill at 1000 RPM for 18 h. Cooling water was used to cool the ball mill throughout the ball milling process to maintain a ball milling temperature of 15 ± 5 °C. After ball milling, the powder was removed.

[0062] The powder is pressed into a block using a cold press, sealed in an ampoule, and sintered in a muffle furnace at 400°C for 24 hours. The sintered electrolyte sheet is ground into powder to obtain the corresponding Li9GaP4 solid electrolyte.

[0063] (2) Preparation of solid-state battery: The steps for preparing the solid-state battery in Example 2 are the same as those in Example 1, except that 1.746 g of Li9AlP4 is replaced by 1.746 g of Li9GaP4. The obtained solid-state battery is denoted as C2.

[0064] Example 3

[0065] (1) Preparation of phosphide solid electrolyte: In a glove box, 14Accurately weigh 5 g of lithium metal powder, silicon powder, and red phosphorus powder in a stoichiometric ratio for SiP6. Place the powder in a zirconia-lined ball mill. Add zirconia beads to the mill, maintaining a ball-to-bearing ratio of 25:1. Mill the mixture in a high-speed ball mill at 1000 RPM for 18 h. Cool the mill with cooling water throughout the milling process to maintain a temperature of 15 ± 5°C. After milling, remove the powder.

[0066] The powder was pressed into a block using a cold press, and the block was sealed in an ampoule and sintered in a muffle furnace. The sintering temperature was controlled at 700 ° C and the sintering time was 24 hours. The sintered electrolyte sheet was ground into powder to obtain the corresponding Li 14 SiP6 solid electrolyte.

[0067] (2) Preparation of solid-state battery: In addition to replacing 1.746g Li9AlP4 with 1.746g Li 14 Except for SiP6, the steps for preparing the solid-state battery in Example 3 are the same as those in Example 1, and the obtained solid-state battery is denoted as C3.

[0068] Example 4

[0069] (1) Preparation of phosphide solid electrolyte:

[0070] In the glove box, follow Li 14 Accurately weigh 5g of lithium metal powder, germanium powder, and red phosphorus powder in the stoichiometric ratio of GeP6 into a zirconia-lined ball mill. Place zirconia beads into the mill, maintaining a ball-to-bearing ratio of 25:1. Mill the mixture in a high-speed ball mill at 1000 RPM for 18 hours. Cool the mill with cooling water throughout the milling process to maintain a temperature of 15±5°C. After milling, remove the powder.

[0071] The powder was pressed into a block using a cold press, and the block was sealed in an ampoule and sintered in a muffle furnace. The sintering temperature was controlled at 500 ° C and the sintering time was 24 hours. The sintered electrolyte sheet was ground into powder to obtain the corresponding Li 14 GeP6 solid electrolyte.

[0072] (2) Preparation of solid-state battery: In addition to replacing 1.746g Li9AlP4 with 1.746g Li 14 Except for GeP6, the steps for preparing the solid-state battery in Example 4 are the same as those in Example 1, and the obtained solid-state battery is recorded as C4.

[0073] Example 5

[0074] Except that 1.746g Li9AlP4 is replaced by 0.873gLi9AlP4 and 0.873gLi9GaP4 (the preparation steps of Li9GaP4 are the same as those in Example 2), the steps for preparing the solid-state battery in Example 5 are the same as those in Example 1, and the obtained solid-state battery is recorded as C5.

[0075] Example 6

[0076] In addition to replacing Li6PS5Cl with Li7P3S in steps 1, 2, and 3, 11 In addition, the steps for preparing the solid-state battery in Example 6 are the same as those in Example 1, and the obtained solid-state battery is recorded as C6.

[0077] Example 7

[0078] The steps for preparing a solid-state battery in Example 7 were essentially the same as those in Example 1, except that in step 2, 58.2 g of Li6PS5Cl and 1.8 g of nitrile rubber binder were replaced with 51 g of Li6PS5Cl and 9 g of nitrile rubber binder. The resulting solid-state battery was designated C7.

[0079] Example 8

[0080] The steps for preparing a solid-state battery in Example 8 were essentially the same as those in Example 1, except that in Step 3, the mixed powder of 1.746 g of Li9AlP4 and 4.074 g of Li6PS5Cl and 0.18 g of nitrile rubber binder was replaced with a mixed powder of 1.53 g of Li9AlP4 and 3.57 g of Li6PS5Cl and 0.9 g of nitrile rubber binder. The resulting solid-state battery was designated C8.

[0081] Example 9

[0082] The steps for preparing a solid-state battery in Example 9 are essentially the same as those in Example 1, except that in step 3, the mixed powder of 1.746 g of Li9AlP4 and 4.074 g of Li6PS5Cl is replaced with a mixed powder of 5.238 g of Li9AlP4 and 0.582 g of Li6PS5Cl. The resulting solid-state battery is designated C9.

[0083] Example 10

[0084] The steps for preparing the solid-state battery in Example 10 were essentially the same as those in Example 1, except that in Step 3, the mixed powder of 1.746 g of Li9AlP4 and 4.074 g of Li6PS5Cl was replaced with a mixed powder of 0.291 g of Li9AlP4 and 5.529 g of Li6PS5Cl. The resulting solid-state battery was designated C10.

[0085] Example 11

[0086] The steps for preparing a solid-state battery in Example 11 are essentially the same as those in Example 1, except that in step 3, the mixed powder of 1.746 g of Li9AlP4 and 4.074 g of Li6PS5Cl is replaced with 5.82 g of Li9AlP4 powder. The resulting solid-state battery is designated C11.

[0087] Example 12

[0088] The steps for preparing a solid-state battery in Example 12 were essentially the same as those in Example 1, except that in step 3, the mixed powder of 1.746 g of Li9AlP4 and 4.074 g of Li6PS5Cl was replaced with a mixed powder of 0.116 g of Li9AlP4 and 5.704 g of Li6PS5Cl. The resulting solid-state battery was designated C12.

[0089] Example 13

[0090] The steps for preparing a solid-state battery in Example 13 are essentially the same as those in Example 1, except that in step 3, the mixed powder of 1.746 g of Li9AlP4 and 4.074 g of Li6PS5Cl is replaced with a mixed powder of 4.074 g of Li9AlP4 and 1.746 g of Li6PS5Cl. The resulting solid-state battery is designated C13.

[0091] Example 14

[0092] The steps for preparing a solid-state battery in Example 14 are basically the same as those in Example 1, with the only difference being:

[0093] In step 2, the mass ratio of Li6PS5Cl and nitrile rubber binder remains unchanged, and the total mass of Li6PS5Cl and nitrile rubber binder is adjusted so that the thickness of the first solid electrolyte layer is 10 μm;

[0094] In step 3, the mass ratio of Li9AlP4, Li6PS5Cl and nitrile rubber binder remains unchanged, and the total mass of Li9AlP4, Li6PS5Cl and nitrile rubber binder is adjusted so that the thickness of the second solid electrolyte layer is 15 μm.

[0095] The obtained solid-state battery is recorded as C14.

[0096] Example 15

[0097] The steps for preparing a solid-state battery in Example 15 are basically the same as those in Example 1, with the only difference being:

[0098] In step 2, the mass ratio of Li6PS5Cl and the nitrile rubber binder remains unchanged, and the total mass of Li6PS5Cl and the nitrile rubber binder is adjusted so that the thickness of the first solid electrolyte layer is 200 μm;

[0099] In step 3, the mass ratio of Li9AlP4, Li6PS5Cl and nitrile rubber binder remains unchanged, and the total mass of Li9AlP4, Li6PS5Cl and nitrile rubber binder is adjusted so that the thickness of the second solid electrolyte layer is 1 μm.

[0100] The obtained solid-state battery is recorded as C15.

[0101] Example 16

[0102] The steps for preparing a solid-state battery in Example 16 are basically the same as those in Example 1, with the only difference being:

[0103] In step 2, the D50 of Li6PS5Cl was 8 μm. In step 3, the D50 of Li6PS5Cl was 2.2 μm, and the D50 of Li9AlP4 was 2.2 μm.

[0104] Example 17

[0105] The steps for preparing a solid-state battery in Example 17 are basically the same as those in Example 1, with the only difference being:

[0106] In step 2, the D50 of Li6PS5Cl was 11 μm. In step 3, the D50 of Li6PS5Cl was 4 μm, and the D50 of Li9AlP4 was 3 μm.

[0107] Comparative Example 1

[0108] The steps for preparing a solid-state battery in Comparative Example 1 are basically the same as those in Example 1, except that:

[0109] In step 3 of preparing the solid-state battery, the mixed powder of 1.746 g of Li9AlP4 and 4.074 g of Li6PS5Cl was replaced with 5.82 g of Li6PS5Cl powder. The resulting solid-state battery is designated DC1.

[0110] Comparative Example 2

[0111] (1) Li9AlP4 was prepared using the same steps as in Example 1.

[0112] (2) Preparation of solid-state batteries:

[0113] All the following steps are completed in a drying room with a dew point below -50°C.

[0114] Step 1: Add 75g of NCM622 positive electrode material, 20g of solid electrolyte Li6PS5Cl, 3g of nitrile rubber binder, and 2g of acetylene black to 100g of xylene solvent, then stir in a vacuum mixer to form a stable and uniform positive electrode slurry. The positive electrode slurry is evenly and intermittently coated on both sides of aluminum foil (aluminum foil size: width 160mm, thickness 16μm), then dried at 373K, and rolled on a roller press to form a single-sided positive electrode material layer with a thickness of 80μm on both sides of the aluminum foil to obtain a positive electrode sheet.

[0115] Step 2: 62.274g of Li6PS5Cl, 1.746g of Li9AlP4, and 1.98g of nitrile rubber binder were added to 66g of xylene solution and stirred thoroughly until a stable, uniform slurry was formed. This solution was then applied continuously to the positive electrode sheet and dried at 373K to form a positive electrode sheet-solid electrolyte layer composite. The solid electrolyte layer had a thickness of 55μm.

[0116] In step 2, the D50 of Li6PS5Cl is 4 μm, and the D50 of Li9AlP4 is 1 μm.

[0117] Step 3: Cut the positive electrode sheet-solid electrolyte layer composite layer into a positive electrode sheet-solid electrolyte layer composite membrane with a length × width of 21 mm × 41 mm.

[0118] Step 4: Select lithium copper composite foil as the negative electrode, with a lithium layer thickness of 15 μm, and cut it into a 20 mm × 40 mm negative electrode film.

[0119] Step 5: Align the positive electrode sheet-solid electrolyte layer composite membrane obtained in Step 3 and the negative electrode membrane obtained in Step 4 and place them in a hot press. Press at 453K for 1 hour and a pressure of 200 MPa. Vacuum seal with aluminum-plastic film and remove the sample. Finally, press the pressed sample in an isostatic press at 200 MPa for 300 seconds to obtain the solid-state battery of this example. The resulting solid-state battery is designated DC2.

[0120] Comparative Example 3

[0121] (1) Li9AlP4 was prepared using the same steps as in Example 1.

[0122] (2) Preparation of solid-state batteries:

[0123] All the following steps are completed in a drying room with a dew point below -50°C.

[0124] Step 1: 75g of NCM622 positive electrode material, 20g of solid electrolyte Li9AlP4, 3g of nitrile rubber binder, and 2g of acetylene black were added to 100g of xylene solvent and stirred in a vacuum mixer to form a stable and uniform positive electrode slurry. The positive electrode slurry was evenly and intermittently coated on both sides of aluminum foil (aluminum foil size: width 160mm, thickness 16μm), then dried at 373K, and after roller pressing, a single-sided positive electrode material layer with a thickness of 80μm was formed on both sides of the aluminum foil to obtain a positive electrode sheet.

[0125] Step 2: 64.02g of Li9AlP4 and 1.98g of nitrile rubber binder were placed in 66g of xylene solution and stirred thoroughly until a stable, uniform slurry was formed. This solution was continuously coated onto the positive electrode sheet and then dried at 373K to obtain a positive electrode sheet-solid electrolyte layer composite. The solid electrolyte layer had a thickness of 55μm. In Step 2, the D50 of Li9AlP4 was 4μm.

[0126] Step 3: Cut the positive electrode sheet-solid electrolyte layer composite layer into a positive electrode sheet-solid electrolyte layer composite membrane with a length × width of 21 mm × 41 mm.

[0127] Step 4: Select lithium copper composite foil as the negative electrode, with a lithium layer thickness of 15 μm, and cut it into a 20 mm × 40 mm negative electrode film.

[0128] Step 5: Align the positive electrode sheet-solid electrolyte layer composite membrane obtained in Step 3 and the negative electrode membrane obtained in Step 4 and place them in a hot press. Press at 453K for 1 hour and a pressure of 200 MPa. Vacuum seal with aluminum-plastic film and remove the sample. Finally, press the pressed sample in an isostatic press at 200 MPa for 300 seconds to obtain the solid-state battery of this example. The resulting solid-state battery is designated DC3.

[0129] The solid-state batteries C1-C17 and DC1-DC3 obtained in Examples 1-17 and Comparative Examples 1-3 were subjected to battery cycle life tests, and the test method was as follows:

[0130] Take 5 batteries prepared in each embodiment and comparative example, and perform charge-discharge cycle test on LAND CT 2001C secondary battery performance test device at 298±1K at 0.1C. The steps are as follows: set aside for 10 minutes; charge at constant current until 4.2V is cut off; set aside for 10 minutes, then discharge at constant current until 2.6V is reached, which is 1 cycle, and record the first discharge capacity. The first discharge specific capacity = first discharge capacity / mass of positive electrode active material. Repeat this step, and use electrochemical workstation EIS to record the AC impedance of the battery at 100% SOC for 1, 10, and 20 cycles, and take the average value of each group as the cycle impedance, which is recorded as 1st Impedance, 10 th Impedance, 20 th Impedance; when the battery capacity is lower than 80% of the initial discharge capacity during the cycle, the cycle is terminated. The number of cycles at this time is the cycle life of the battery. The average value of each group is taken. The data of this parameter and the average initial discharge capacity of the battery are shown in the following table.

[0131] Table 1 Electrochemical performance data of each embodiment

[0132] The reduction potential of each solid electrolyte was tested by CV curve: specifically, the electrolytes of the second solid electrolyte layer of Examples 1-17 and Comparative Example 1, and the electrolytes of the solid electrolyte layers of Comparative Examples 2 and 3 were taken respectively, and 10 mg of the electrolyte of each second solid electrolyte layer or solid electrolyte layer was uniformly mixed with 0.1 mg of acetylene black, and used as one side of the battery electrode. A 15 μm thick, φ15 mm lithium-copper composite foil was used as the counter electrode, and 260 mg of Li6PS5Cl was used as the intermediate electrolyte layer. A button battery 1 was assembled, and the button battery 1 was connected to an electrochemical workstation. The CV program was used to scan from the OCV state to 0V at a rate of 0.1 mV / s. The voltage when the reduction current appeared was recorded as the reduction potential of the electrolyte.

[0133] Weigh 260 mg of the second solid electrolyte layer or the electrolyte of the solid electrolyte layer and place it in a circular mold with a diameter of 15 mm. After preforming the electrolyte sheet on a powder cold press at 50 MPa, attach φ15 mm carbon-coated aluminum foil on both sides of the electrolyte and form it again at 500 MPa. Press the carbon-coated aluminum foil onto the electrolyte sheet and accurately measure the thickness of the electrolyte layer using a micrometer screw, which is recorded as L. Then, package it in a 2025 button battery box to form Battery 2.

[0134] Connect the battery 1 to the electrochemical workstation and use the EIS program with an amplitude of 10 mV and a scanning frequency range of 7 MHz to 1 Hz to measure the impedance R1 of the electrolyte sheet and the initial ionic conductivity σ of the electrolyte. i The formula σ i =L / R1S where S = πd 2 / 4.

[0135] Use the DC polarization program (PPI), set the voltage to U = 50mV, test time 1h, test the steady-state current I of battery 2 in this state, and calculate the impedance R2 = U / I. According to σ c =L / R2S The electronic conductivity of the electrolyte in the second solid electrolyte layer can be calculated.

[0136] In Table 2, “second solid electrolyte layer or solid electrolyte layer electrolyte” refers to the electrolyte of the second solid electrolyte layer of Examples 1-17 and Comparative Example 1 or the electrolyte of the solid electrolyte layer of Comparative Examples 2 and 3.

[0137] Table 2 Reduction potential, ionic conductivity and electronic conductivity of each solid electrolyte

[0138] The composition of the electrolyte interface layer can be tested using XPS. The battery's negative electrode sheet is peeled off, and the sample surface is irradiated with X-rays. The escaping photoelectrons are collected to form a characteristic photoelectron spectrum. After calibrating, smoothing, and background subtraction, the spectrum is subjected to peak separation. The composition and proportion of the interface layer are determined based on peak position and area.

[0139] Table 3 Negative electrode interface layer thickness, composition and ratio

[0140] From the above data, it can be seen that Comparative Example 1 does not contain phosphide, the interface layer impedance is high, resulting in a short battery cycle life. Comparative Example 2 does not have a first sulfide electrolyte layer, which will lead to a high overall electronic conductivity of the battery, resulting in self-discharge, thereby affecting battery performance. Secondly, the phosphide electrolyte is in direct contact with the positive electrode layer and is more easily oxidized by the positive electrode, resulting in more side reactions on the positive electrode side, thereby affecting battery performance. Comparative Example 3 uses all phosphide solid electrolytes instead of sulfide solid electrolytes in the solid electrolyte, and has the same and more serious problems as Comparative Example 2.

[0141] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0142] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise clearly defined.

[0143] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

DEPCT681. A solid electrolyte consisting of a first solid electrolyte layer and a second solid electrolyte layer; the first solid electrolyte consisting of a first sulfide solid electrolyte and the second solid electrolyte layer consisting of a phosphide solid electrolyte.

2. A solid electrolyte according to claim 1 where the phosphide solid electrolyte is composed of a phosphorus element whose valence is -3.

3. A solid electrolyte according to claim 1 or 2 where the reduction potential of the phosphide solid electrolyte is between 0 volts and 1.2 volts.

4. Any one of the solid electrolytes according to claim 1 to 3 where the phosphide solid electrolyte is at least one of Li3x-3APx and Li3y-4BPy; the element P has a valence of -3; element A is chosen from at least one of Al, Ga, and In; element B is chosen from at least one of Si, Ge, and Snx; is an integer between 2 and 4; and y is an integer between 2 and 6. 5.Solid electrolytes under any of the claims 1 through 4 in which the phosphide solid electrolyte consists of one or more of the following: Li9AlP4, Li9GaP4, Li9InP4, Li3AlP2, Li3GaP2, Li3InP2, Li8SiP4, Li8GeP4, Li8SnP4, Li2SiP2, Li2GeP2, Li2SnP2, Li14SiP6 and Li14GeP6.

6. Electrolytes Solid electrolytes under any one of claims 1 through 5, in which one or more first solid sulfide electrolytes are selected from Li3PS4, Li10GeP2S12, Li9.54Si1.74P1.44S11.7Cl0.3, Li6-zPS5-zCl1+z,Lil-(70Li2S-30P2S5), Li7P3S11, Li4PS4I, Li7P2S8I and Li2SiS3. In Li6-zPS5-zCl1+z, the range of z is 0 less than or equal to z less than or equal to 17. A solid electrolyte under any of the claims 1 to 6 where the total mass of the first solid electrolyte layer is used as a reference and the amount of the first sulfide solid electrolyte in the first solid electrolyte layer is between 90 percent by weight and 99.9 percent by weight.

8. A solid electrolyte under any of the claims 1 to 7 where the second solid electrolyte layer is additionally composed of the second sulfide solid electrolyte. 9.Solid electrolytes according to claim 8, where the total mass of the second solid electrolyte layer is used as a reference, and the amounts of the second solid sulfide electrolyte and the solid phosphide electrolyte in the second solid electrolyte layer are between 90 percent by weight and 99.9 percent by weight, and the total mass of the second solid sulfide electrolyte and the solid phosphide electrolyte in the second solid electrolyte layer is used as a reference, and in the second solid electrolyte layer, the amount of the second solid sulfide electrolyte is between 10 percent by weight and 95 percent by weight, and the amount of the solid phosphide electrolyte is between 5 percent by weight and 90 percent by weight.10.Solid electrolyte according to claim 9 where the total mass of the second solid sulfide electrolyte and the solid phosphide electrolyte in the second solid electrolyte layer is used as a reference, and in the second solid electrolyte layer the amount of the second solid sulfide electrolyte is between 30 percent by weight and 70 percent by weight, and the amount of the solid phosphide electrolyte is between 30 percent by weight and 70 percent by weight.

11. Solid electrolyte according to claims 8 to 10, either one of which the electrolyte One or more second solid sulfide electrolytes are selected: Li3PS4, Li10GeP2S12, Li9.54Si1.74P1.44S11.7Cl0.3, Li6-zPS5-zCl1+z, LiI-(70Li2S-30P2S5), Li7P3S11, Li4PS4I, Li7P2S8I, and Li2SiS3, and in Li6-zPS5-zCl1+z, the range of z is 0 less than or equal to x less than or equal to 112. A solid electrolyte according to any of the claims 1 to 11 is selected in which the thickness of the first solid electrolyte layer is between 15 µm and 200 µm and the thickness of the second solid electrolyte layer is between 1 µm and 15 µm.13.

14. Solid electrolyte according to any one of the claims 1 through 12 where the thickness of the first solid electrolyte layer is between 15 micrometers and 50 micrometers and the thickness of the second solid electrolyte layer is between 3 micrometers and 7 micrometers.

15. Solid electrolyte according to any one of the claims 8 through 11 where the D50 of the first sulfide solid electrolyte is between 1 micrometer and 10 micrometers, the D50 of the phosphide solid electrolyte is between 0.5 micrometers and 4 micrometers, and the D50 of the second sulfide solid electrolyte is between 0.5 micrometers and 4 micrometers.

15. Solid-state batteries comprising an anode, cathode, and a solid electrolyte according to any one of the claims 1 through 14, where the solid electrolyte is arranged between the anode and cathode electrodes, the first solid electrolyte layer is arranged between the anode and the second solid electrolyte layer, and the second solid electrolyte layer is arranged between the first solid electrolyte layer and the cathode electrode. 16.Solid-state batteries under claim 15 in which, after the solid-state battery is first charged and discharged, an interface layer is formed between a second solid electrolyte layer and the negative electrode, and the interface layer is incorporated with Li3P17. Solid-state batteries under claim 16 in which the amount of Li3P in the interface layer is between 5 percent by weight and 25 percent by weight based on the mass of the interface layer18. Solid-state batteries under claim 16 or 17 in which the interface layer is incorporated further. The battery is filled with one or more Li2S, Li2Sa, LiX, M1bP, and M2cS. X is one or more F, Cl, Br, and I. Each M1 and M2 is independently selected from one or more Si, Ge, Sn, Al, Ga, and In. The range of values ​​of a, b, and c, respectively, is 2 less than or equal to a less than or equal to 8, 0.75 less than or equal to b less than or equal to 1.5, and 0.5 less than or equal to c less than or equal to 1.

19. A solid-state battery according to any one of claims 15 through 18 in which the negative electrode is composed of lithium metal or lithium alloy.20.Electrical devices incorporating solid-state batteries as per any of claims 15 through 19;