Solid-state battery and its preparation method and application

Abstract

The present invention discloses a solid-state battery, its preparation method, and application. The solid-state battery includes a negative electrode sheet and a positive electrode sheet. A first solid electrolyte layer is provided on both sides of the negative electrode sheet, and the first solid electrolyte layer includes a polymer electrolyte. A second solid electrolyte layer is provided on both sides of the positive electrode sheet. The positive and negative electrode sheets are alternately stacked, wherein the second solid electrolyte layer includes an inorganic solid electrolyte, a polymer monomer, an initiator, a binder, and a lithium salt. The solid-state battery uses a double-layer solid electrolyte, that is, the positive and negative electrodes are matched with different solid electrolyte layers. The double-layer solid electrolyte can effectively reduce side reactions between the positive and negative electrodes and the solid electrolyte. The double-layer solid electrolyte has a high conductivity and can meet the requirements of lithium-ion batteries for electrolytes, making it possible to match high-voltage positive electrodes, thereby obtaining a solid-state battery with good capacity, good safety performance, and long cycle life.

Description

Technical Field

[0001] The present invention belongs to the technical field of lithium-ion batteries, and in particular relates to a solid-state battery and a preparation method and application thereof. Background Art

[0002] Most lithium-ion batteries currently in practical use utilize liquid electrolytes composed of organic solvents and lithium salts. However, liquid electrolytes have insufficient safety performance, posing safety risks such as flammability, explosiveness, and poor thermal stability. They also experience side reactions with the positive and negative electrodes, easily generating gas, a key cause of thermal runaway in lithium batteries. Furthermore, the energy density of liquid lithium-ion batteries has limited room for improvement, and they are approaching their theoretical capacity limit. Developing all-solid-state batteries based on solid-state electrolytes is a fundamental strategy to eliminate these safety risks. Furthermore, solid-state electrolytes often exhibit considerable stability in contact with lithium metal anodes, making technologies such as lithium metal batteries, lithium-sulfur batteries, and lithium-air batteries possible, potentially offering even higher energy density limits. Solid-state electrolytes are categorized into polymer solid electrolytes and inorganic solid electrolytes. Polymer electrolytes have become a hot topic of research due to their high flexibility, excellent interfacial contact properties, and compatibility with existing battery process equipment.

[0003] Currently, commonly used polymer solid electrolytes are polyether polymers (such as polyethylene oxide (PEO)). They have advantages such as good flexibility and good compatibility with lithium metal anodes. However, their oxidation potential is too low to match high-capacity cathode materials, limiting their further application. Solid electrolytes with good oxidation resistance, such as polycarbonate solid electrolytes, have poor stability with lithium metal anodes and tend to form a thick negative electrode impedance layer.

[0004] Therefore, existing solid-state batteries need to be improved. Summary of the Invention

[0005] The present invention aims to solve at least one of the technical problems in the related art to a certain extent. To this end, one purpose of the present invention is to propose a solid-state battery and its preparation method and application, wherein the solid-state battery adopts a double-layer solid electrolyte, that is, the positive and negative electrodes are matched with different solid electrolyte layers, and the double-layer solid electrolyte can effectively reduce the side reactions between the positive and negative electrodes and the solid electrolyte. The double-layer solid electrolyte has a high conductivity and can meet the requirements of lithium-ion batteries for electrolytes, making it possible to match high-voltage positive electrodes, thereby obtaining a solid-state battery with good capacity, good safety performance and long cycle life.

[0006] In one aspect of the present invention, a solid-state battery is provided. According to an embodiment of the present invention, the solid-state battery comprises:

[0007] A negative electrode plate, wherein a first solid electrolyte layer is provided on both sides of the negative electrode plate, and the first solid electrolyte layer includes a polymer electrolyte;

[0008] A positive electrode plate, wherein a second solid electrolyte layer is provided on both side surfaces of the positive electrode plate, and the positive electrode plate and the negative electrode plate are alternately stacked, wherein the second solid electrolyte layer includes an inorganic solid electrolyte, a polymer monomer, an initiator, a binder and a lithium salt.

[0009] According to the solid-state battery of an embodiment of the present invention, a first solid electrolyte layer including a polymer electrolyte is provided on both side surfaces of the negative electrode plate. The polymer solid electrolyte (such as polyethylene oxide PEO) has the advantages of good flexibility and good compatibility with the lithium metal negative electrode. Its interface impedance is low, and it can well contact with the negative electrode active material and play the role of conducting ions. However, its oxidation potential is too low (<4eV) to match the high-capacity positive electrode material. A second solid electrolyte layer composed of an inorganic solid electrolyte, a polymer monomer, an initiator, a binder, and a lithium salt is disposed on both sides of the positive electrode sheet. The second solid electrolyte, with the inorganic solid electrolyte as one of the main materials, has good oxidation resistance and high ion conductivity (close to that of a liquid electrolyte). By working with the first solid electrolyte layer containing a polymer solid electrolyte, it can effectively reduce contact impedance and well match the high-voltage positive electrode. That is, different solid electrolyte layers are matched with the positive electrode sheet and the negative electrode sheet respectively. The second solid electrolyte layer has good contact with the positive electrode sheet, thereby being able to conduct lithium ions from the positive electrode sheet side, reducing the interface resistance of the positive electrode sheet. The positive and negative electrode sheets are then alternately stacked, that is, a solid electrolyte comprising the first solid electrolyte layer and the second solid electrolyte layer is formed between the positive and negative electrode sheets. This double-layer solid electrolyte can effectively reduce side reactions between the positive and negative electrodes and the solid electrolyte. The double-layer solid electrolyte has high conductivity, can meet the electrolyte requirements of lithium-ion batteries, and makes it possible to match the high-voltage positive electrode, thereby obtaining a solid-state battery with good capacity, good safety performance, and long cycle life.

[0010] In addition, the solid-state battery according to the above embodiment of the present invention may also have the following additional technical features:

[0011] In some embodiments of the present invention, the thickness of the first solid electrolyte layer is 5-70 μm.

[0012] In some embodiments of the present invention, the polymer electrolyte comprises at least one of polyethylene oxide, polyether polyol, polyphenylene oxide, polyvinylidene fluoride-hexafluoropropylene, and modified polyethylene oxide. As a result, the polymer electrolyte is well compatible with the negative electrode, thereby improving the capacity and safety of the solid-state battery.

[0013] In some embodiments of the present invention, the first solid electrolyte layer further includes the lithium salt.

[0014] In some embodiments of the present invention, based on the total mass of the first solid electrolyte layer, the polymer electrolyte accounts for no less than 85%.

[0015] In some embodiments of the present invention, the thickness of the second solid electrolyte layer is 30-200 μm.

[0016] In some embodiments of the present invention, the mass ratio of the inorganic solid electrolyte, the polymer monomer, the initiator, the binder, and the lithium salt is (20-80):(5-40):(0.1-5):(5-20):(1-10). This can improve the capacity and safety performance of solid-state batteries.

[0017] In some embodiments of the present invention, the inorganic solid electrolyte includes at least one of lithium titanium aluminum phosphate, a doped and modified compound of lithium titanium aluminum phosphate, lithium germanium aluminum phosphate, a doped and modified compound of lithium germanium aluminum phosphate, lithium lanthanum zirconium oxide, a doped and modified compound of lithium lanthanum zirconium oxide, lithium lanthanum titanium oxide, a doped and modified compound of lithium lanthanum titanium oxide, lithium lanthanum zirconium oxide and a doped and modified compound of lithium lanthanum zirconium oxide.

[0018] In some embodiments of the present invention, the polymer monomer includes at least one of vinyl vinyl sulfite, vinyl ethylene carbonate, methyl vinyl sulfone, ethyl vinyl sulfone, methyl methacrylate and vinyl acetate.

[0019] In some embodiments of the present invention, the initiator includes a polymerization initiator, and the polymerization initiator includes at least one of azobisisobutyronitrile, azobisisoheptanenitrile, dimethyl azobisisobutyrate, benzoyl peroxide, tert-butyl benzoyl peroxide and methyl ethyl ketone peroxide.

[0020] In some embodiments of the present invention, the binder includes at least one of polyvinylidene fluoride, a polyether binder, and polyacrylonitrile.

[0021] In some embodiments of the present invention, the lithium salt includes at least one of lithium perchlorate, lithium tetrafluoroborate, lithium hexafluoroarsenate, lithium hexafluorophosphate, lithium bis(trifluoromethylsulfonyl)imide, lithium bis(fluorosulfonyl)imide, lithium trifluoromethylsulfonate, lithium bis(oxalatoborate) and lithium difluorooxalatoborate.

[0022] In some embodiments of the present invention, the solid-state battery includes a separator, which is disposed between the positive electrode plate and the negative electrode plate.

[0023] In another aspect, the present invention provides a method for preparing the above-mentioned solid-state battery. According to an embodiment of the present invention, the method includes:

[0024] (1) providing a negative electrode plate, wherein a first solid electrolyte layer is formed on both sides of the negative electrode plate;

[0025] (2) Alternately stacking the negative electrode sheets and the positive electrode sheets to obtain a pole core;

[0026] (3) After the electrode core is encapsulated with an aluminum-plastic film or placed in a shell, a prepolymer solution is injected to form a second solid electrolyte layer between the first solid electrolyte layer and the positive electrode plate, wherein the prepolymer solution includes an inorganic solid electrolyte, a polymer monomer, an initiator, a binder and a lithium salt.

[0027] According to the method for preparing the above-mentioned solid-state battery in an embodiment of the present invention, a negative electrode sheet and a positive electrode sheet with a first solid electrolyte layer on both sides are alternately stacked to form a pole core, and then the pole core is encapsulated with an aluminum-plastic film or after being placed in a shell, a prepolymer solution including an inorganic solid electrolyte, a polymer monomer, an initiator, a binder and a lithium salt is injected, wherein the polymer monomer undergoes in-situ polymerization with the inorganic solid electrolyte and the lithium salt under the action of the initiator, and a second solid electrolyte layer is formed between the first solid electrolyte layer and the positive electrode sheet, that is, different solid electrolyte layers are matched on the positive electrode sheet and the negative electrode sheet respectively. The second solid electrolyte layer has good contact with the positive electrode sheet, so that lithium ions can be extracted from the positive electrode sheet side, reducing the interface resistance of the positive electrode sheet. At the same time, the first solid electrolyte layer and the second solid electrolyte layer constitute a solid electrolyte between the positive electrode sheet and the negative electrode sheet. The double-layer solid electrolyte can effectively reduce the side reactions between the positive and negative electrodes and the solid electrolyte, and the double-layer solid electrolyte has a high conductivity, which can meet the requirements of lithium-ion batteries for electrolytes, making it possible to match high-voltage positive electrodes, thereby obtaining a solid-state battery with good capacity, good safety performance and long cycle life.

[0028] In addition, the method for preparing a solid-state battery according to the above embodiment of the present invention may also have the following additional technical features:

[0029] In some embodiments of the present invention, before the negative electrode sheets and the positive electrode sheet substrates are alternately stacked, a separator is pre-installed on both sides of the negative electrode sheets.

[0030] In yet another aspect, the present invention provides a vehicle. According to an embodiment of the present invention, the vehicle comprises the aforementioned solid-state battery or a solid-state battery obtained using the aforementioned method. Thus, the vehicle is equipped with the aforementioned solid-state battery with excellent capacity, safety, and cycle life, thereby providing a long driving range and enhanced safety.

[0031] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments with reference to the following drawings, in which:

[0033] Figure 1 1 is a structural diagram of the positive and negative electrodes and double-layer solid electrolyte of a solid-state battery according to an embodiment of the present invention;

[0034] Figure 2 This is a structural diagram of the positive and negative electrodes, separator, and double-layer solid electrolyte of a solid-state battery according to one embodiment of the present invention;

[0035] Figure 3 It is a schematic flow chart of a method for preparing a solid-state battery according to one embodiment of the present invention. DETAILED DESCRIPTION

[0036] The present invention is described below with reference to specific examples. It should be noted that these examples are merely illustrative and do not limit the present invention in any way.

[0037] In one aspect of the present invention, a solid-state battery is provided. Figure 1 The solid-state battery includes a negative electrode sheet 100 and a positive electrode sheet 200.

[0038] According to an embodiment of the present invention, referring to Figure 1 A first solid electrolyte layer 11 is provided on both side surfaces of the negative electrode plate 100, wherein the first solid electrolyte layer 11 includes a polymer electrolyte, and those skilled in the art can select the specific type of polymer electrolyte according to actual needs. For example, the polymer electrolyte includes at least one of polyethylene oxide, polyether polyol, polyphenylene ether, polyvinylidene fluoride-hexafluoropropylene and modified polyethylene oxide, preferably polyethylene oxide modified with small molecule inorganic substances.

[0039] In order to improve the conductivity of the first solid electrolyte layer 11, the first solid electrolyte layer 11 may further include a lithium salt, and the polymer electrolyte accounts for no less than 85% of the total mass of the first solid electrolyte layer 11. Those skilled in the art may select the type of lithium salt according to actual needs. For example, the lithium salt may include at least one of lithium perchlorate, lithium tetrafluoroborate, lithium hexafluoroarsenate, lithium hexafluorophosphate, lithium bis(trifluoromethylsulfonylimide), lithium bis(fluorosulfonylimide), lithium trifluoromethylsulfonate, lithium bis(oxalatoborate), and lithium difluorooxalatoborate.

[0040] According to a specific embodiment of the present invention, the thickness of the above-mentioned first solid electrolyte layer 11 is 5-70μm, preferably 25μm. The inventors have found that if the thickness of the first solid electrolyte layer 11 is too high, the interface resistance will be too high and the battery energy density will be reduced; if the thickness of the first solid electrolyte layer 11 is too low, it will not be able to effectively cover the surface of the negative electrode, the ion conduction effect will be poor, and the production process will be too difficult. It should be explained that in this application, the "thickness of the first solid electrolyte layer 11" refers to the thickness of the first solid electrolyte layer 11 on a single side of the negative electrode plate 100.

[0041] It should be noted that the structure and materials of the negative electrode plate 100 of the present application are conventional in the art and can be selected by those skilled in the art based on actual needs. For example, the negative electrode active material in the negative electrode plate 100 is selected from at least one of metallic lithium, lithium alloys, graphite, mesophase carbon microbeads, and silicon-carbon materials, preferably a metallic lithium negative electrode. Furthermore, those skilled in the art can form the first solid electrolyte layer 11 on the surface of the negative electrode plate 100 using coating methods well known in the art, such as tape casting, extrusion coating, and spraying. Preferably, a slurry comprising a polymer electrolyte is applied to the surface of the negative electrode plate 100 using extrusion coating, followed by roller pressing to ensure a good bond between the negative electrode plate 100 and the first solid electrolyte layer 11.

[0042] According to an embodiment of the present invention, referring to Figure 1 A second solid electrolyte layer 21 is provided on both side surfaces of the positive electrode sheet 200, wherein the second solid electrolyte layer 21 includes an inorganic solid electrolyte, a polymer monomer, an initiator, a binder and a lithium salt. The second solid electrolyte layer 21 composed of this composition is in good contact with the positive electrode sheet 200, so that lithium ions can be extracted from the positive electrode sheet 200 side, reducing the interface resistance of the positive electrode sheet 200. Then the positive electrode sheet 200 and the negative electrode sheet 100 are alternately stacked, that is, a solid electrolyte 10 including a first solid electrolyte layer 11 and a second solid electrolyte layer 21 is formed between the positive electrode sheet 200 and the negative electrode sheet 100. The double-layer solid electrolyte can effectively reduce the side reaction between the positive and negative electrodes and the solid electrolyte, and the double-layer solid electrolyte has a high conductivity, which can meet the requirements of lithium-ion batteries for electrolytes, making it possible to match high-voltage positive electrodes, thereby obtaining a solid-state battery with good capacity, good safety performance and long cycle life.

[0043] According to a specific embodiment of the present invention, the mass ratio of the inorganic solid electrolyte, polymer monomer, initiator, binder and lithium salt in the second solid electrolyte layer 21 is (20-80): (5-40): (0.1-5): (5-20): (1-10). The inventors found that if the amount of inorganic solid electrolyte added is too high, it will lead to a decrease in the mechanical properties of the second solid electrolyte, a decrease in the interface contact effect, and an increase in the interface impedance. If the amount of inorganic solid electrolyte added is too low, it will lead to a decrease in the ionic conductivity of the second solid electrolyte; if the amount of polymer monomer added is too high, it will lead to a decrease in the in-situ polymerization effect. If the amount of polymer monomer added is too low, the in-situ polymerization reaction cannot be effectively carried out. Therefore, the second solid electrolyte layer 21 of the above composition used in this application can improve its mechanical properties while reducing the interface impedance.

[0044] It should be noted that those skilled in the art can select the components forming the second solid electrolyte layer 21 according to actual needs. The inorganic solid electrolyte can be an oxide inorganic solid electrolyte that is resistant to high voltage, such as lithium titanium aluminum phosphate, a doped modified compound of lithium titanium aluminum phosphate, lithium germanium aluminum phosphate, a doped modified compound of lithium germanium aluminum phosphate, lithium lanthanum zirconium oxide, a doped modified compound of lithium lanthanum zirconium oxide, lithium lanthanum titanium oxide, a doped modified compound of lithium lanthanum titanium oxide, lithium lanthanum zirconium oxide and at least one of a doped modified compound of lithium lanthanum zirconium oxide, preferably a Ta doped modified compound of lithium lanthanum zirconium oxide LLTZO; the polymer monomer includes vinyl sulfite, carbon monoxide, etc. The invention relates to a novel polymerizable polymer comprising: a polymerizable polymer comprising: a polymerizable polymer selected from the group consisting of vinyl ethylene oxide, methyl vinyl sulfone, ethyl vinyl sulfone, methyl methacrylate and vinyl acetate; an initiator comprising a polymerization initiator comprising at least one of azobisisobutyronitrile, azobisisoheptylnitrile, dimethyl azobisisobutyrate, benzoyl peroxide, tert-butyl benzoyl peroxide and methyl ethyl ketone peroxide; a binder comprising at least one of polyvinylidene fluoride, a polyether binder and polyacrylonitrile; and a lithium salt comprising at least one of lithium perchlorate, lithium tetrafluoroborate, lithium hexafluoroarsenate, lithium hexafluorophosphate, lithium bistrifluoromethylsulfonyl imide, lithium bisfluorosulfonyl imide, lithium trifluoromethylsulfonate, lithium bisoxalatoborate and lithium difluorooxalatoborate.

[0045] According to a specific embodiment of the present invention, the thickness of the second solid electrolyte layer 21 is 30-200μm, preferably 150μm. The inventors found that if the thickness of the second solid electrolyte layer 21 is too high, it will reduce the overall ion conduction effect and reduce the battery energy density; if the thickness of the second solid electrolyte layer 21 is too low, it will cause excessive process difficulty, affect the ion conduction effect, and may not be able to play the role of separating the positive and negative electrodes, bringing safety risks. It should be explained that in this application, "the thickness of the second solid electrolyte layer 21" refers to the thickness of the second solid electrolyte layer 21 on a single side of the positive electrode sheet 200.

[0046] It should be noted that the structure and materials of the positive electrode plate 200 of the present application are conventional settings in the field, and those skilled in the art can choose according to actual needs. For example, the positive electrode active material in the positive electrode plate 200 is selected from materials familiar to those skilled in the art, such as ternary lithium positive electrode materials, lithium iron phosphate, lithium-rich manganese-based materials, etc., preferably a ternary lithium positive electrode material with a Ni content of 90wt%, and the slurry including the positive electrode active material is coated on the surface of the positive electrode collector and then rolled to prepare the positive electrode plate 200.

[0047] According to an embodiment of the present invention, referring to Figure 2 The solid-state battery further includes a separator 300, which is disposed between the positive electrode sheet 200 and the negative electrode sheet 100. The provision of a separator can effectively reduce the difficulty of solid-state battery production and reduce safety risks. Specifically, the separator 300 is disposed between the first solid electrolyte layer 11 and the second solid electrolyte layer 21. It should be noted that those skilled in the art can select the specific type of separator 300 based on actual needs. For example, the separator 300 may be a PP film, a PE film, etc.

[0048] In another aspect of the present invention, the present invention provides a method for preparing the above-mentioned solid-state battery. Figure 3 , the method comprising:

[0049] S100: A first solid electrolyte layer is formed on both sides of the negative electrode plate

[0050] In this step, a first solid electrolyte slurry is first prepared, which includes a polymer electrolyte or a polymer electrolyte and a lithium salt. The first solid electrolyte slurry is then coated on both sides of the negative electrode plate and rolled to ensure good bonding between the negative electrode plate 100 and the first solid electrolyte layer 11.

[0051] S200: Alternately stack the negative and positive electrodes

[0052] In this step, the negative electrode sheets and the positive electrode sheets are alternately stacked to form a core. It should be noted that the core may include multiple negative electrode sheets and positive electrode sheets. Those skilled in the art can select the number of positive electrode sheets and negative electrode sheets according to actual needs.

[0053] S300: After the core is encapsulated with aluminum-plastic film or placed in the shell, the prepolymer solution is injected

[0054] In this step, the electrode core obtained above is encapsulated with an aluminum-plastic film or placed in a shell, and then a prepolymer solution including an inorganic solid electrolyte, a polymer monomer, an initiator, a binder and a lithium salt is injected. The polymer monomer undergoes in-situ polymerization with the inorganic solid electrolyte and the lithium salt under the action of the initiator, forming a second solid electrolyte layer between the first solid electrolyte layer and the positive electrode sheet. That is, different solid electrolyte layers are matched with the positive electrode sheet and the negative electrode sheet respectively. The second solid electrolyte layer has good contact with the positive electrode sheet, thereby being able to conduct lithium ions from the positive electrode sheet side, reducing the interface resistance of the positive electrode sheet. At the same time, the first solid electrolyte layer and the second solid electrolyte layer constitute a solid electrolyte between the positive electrode sheet and the negative electrode sheet. The double-layer solid electrolyte can effectively reduce the side reaction between the positive and negative electrodes and the solid electrolyte. The double-layer solid electrolyte has a high conductivity and can meet the requirements of lithium-ion batteries for electrolytes, making it possible to match a high-voltage positive electrode, thereby obtaining a solid-state battery with good capacity, good safety performance and long cycle life.

[0055] According to an embodiment of the present invention, the method for preparing a solid-state battery further includes: before alternately stacking the negative electrode sheets and the positive electrode sheet substrate to form the electrode core, pre-installing a separator on both sides of the negative electrode sheet, i.e., on the first solid electrolyte layer on both sides of the negative electrode sheet. Installing the separator can effectively reduce the difficulty of solid-state battery production and reduce safety risks. The prepolymer solution is then injected after encapsulation with aluminum-plastic film or casing, with the separator being disposed between the first solid electrolyte layer and the second solid electrolyte layer.

[0056] In yet another aspect, the present invention provides a vehicle. According to an embodiment of the present invention, the vehicle comprises the aforementioned solid-state battery or a solid-state battery prepared using the aforementioned method. Thus, the vehicle is equipped with the aforementioned solid-state battery, which exhibits excellent capacity, safety, and cycle life, thereby providing a long driving range and enhanced safety.

[0057] The present invention is described below with reference to specific examples. It should be noted that these examples are merely illustrative and do not limit the present invention in any way.

[0058] Preparation of solid-state batteries

[0059] Example 1

[0060] (1) A negative electrode slurry containing artificial graphite with a silicon oxide doping amount of 15 wt% was formed on a negative electrode copper foil current collector, and then rolled to form a negative electrode sheet. A 15 wt% LATP-doped PEO electrolyte slurry was applied to both sides of the negative electrode sheet by extrusion coating, and after curing, the slurry was rolled to form a first solid electrolyte layer (single-side thickness of 25 μm) on both sides of the negative electrode sheet.

[0061] (2) forming a positive electrode slurry including single crystal NCM811 on a positive electrode aluminum foil current collector, and then rolling to form a positive electrode sheet, and alternately stacking the negative electrode sheets and the positive electrode sheets to form a pole core;

[0062] (3) The electrode core is encapsulated with an aluminum-plastic film, and then, under an argon atmosphere, a prepolymer solution comprising 5 wt% lithium bis(trifluoromethanesulfonyl)imide, 0.5 wt% azobisisobutyronitrile, 10 wt% LLZTO, 8 wt% PVDF binder and 10 wt% vinyl sulfite is injected, and the electrode core is allowed to stand at 55°C for 6 hours to form a second solid electrolyte layer between the above-mentioned first solid electrolyte layer and the positive electrode sheet, and finally a solid-state battery with a double-layer solid electrolyte is obtained.

[0063] Example 2

[0064] (1) A negative electrode slurry containing artificial graphite with a silicon oxide doping amount of 20 wt% was formed on a negative electrode copper foil current collector, and then rolled to form a negative electrode sheet. A 15 wt% LATP-doped PEO electrolyte slurry was applied to both sides of the negative electrode sheet by extrusion coating, and after curing, the slurry was rolled to form a first solid electrolyte layer (single-side thickness of 25 μm) on both sides of the negative electrode sheet.

[0065] (2) forming a positive electrode slurry including single crystal NCM9 on the positive electrode aluminum foil current collector, and then rolling to form a positive electrode sheet, and alternately stacking the negative electrode sheets and the positive electrode sheets to form a pole core;

[0066] (3) The electrode core is encapsulated with an aluminum-plastic film, and then, under an argon atmosphere, a prepolymer solution comprising 5 wt% lithium bis(trifluoromethanesulfonyl)imide, 0.5 wt% azobis(isobutyronitrile), 12 wt% LLZTO, 9 wt% PVDF binder and 10 wt% vinyl sulfite is injected, and the electrode core is allowed to stand at 55°C for 6 hours to form a second solid electrolyte layer between the above-mentioned first solid electrolyte layer and the positive electrode sheet, and finally a solid-state battery with a double-layer solid electrolyte is obtained.

[0067] Comparative Example:

[0068] (1) forming a positive electrode slurry including NCM5 on a positive electrode current collector, and then rolling to form a positive electrode sheet;

[0069] (2) forming a negative electrode slurry including artificial graphite on the negative electrode current collector, and then rolling to form a negative electrode sheet, and alternately stacking the positive electrode sheet, the negative electrode sheet and the double-sided adhesive-coated separator to form a pole core;

[0070] (3) The electrode core is encapsulated with an aluminum-plastic film, and then, under the protection of an argon atmosphere, a prepolymer solution containing 5 wt% lithium bis(trifluoromethanesulfonyl)imide, 0.5 wt% azobisisobutyronitrile, 10 wt% LLZTO, 9 wt% PVDF binder and 10 wt% vinyl ethylene sulfite is allowed to stand at 55 ° C for 6 hours to obtain a solid-state battery.

[0071] The performance of the solid-state batteries of Example 1, Example 2 and the comparative example was tested, and the specific test results are shown in Table 1.

[0072] Table 1

[0073] Test items Discharge capacity (mAh / g) 0.33C First effect Capacity retention after 100 cycles of charge and discharge Example 1 155 97％ 94.21％ Example 2 161 96％ 87.91％ Comparative Example 134 95％ 78.33％

[0074] As can be seen from Table 1, the discharge capacity utilization, first efficiency and cycle capacity retention rate of the solid-state batteries obtained in Examples 1-2 are all better than those of the comparative example, indicating that by matching the positive and negative electrodes of the present application with different solid electrolyte layers, a solid-state battery with good capacity utilization, good safety performance and long cycle life can be obtained.

[0075] In the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0076] 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

1. A solid-state battery, characterized in that: include: A negative electrode plate, wherein a first solid electrolyte layer is provided on both sides of the negative electrode plate, and the first solid electrolyte layer includes a polymer electrolyte; A positive electrode sheet, wherein a second solid electrolyte layer is provided on both sides of the positive electrode sheet, and the positive electrode sheet and the negative electrode sheet are alternately stacked; The second solid electrolyte layer is formed by in-situ polymerization of the polymer monomer in the prepolymer solution with the inorganic solid electrolyte and the lithium salt under the action of an initiator. The prepolymer solution includes the inorganic solid electrolyte, the polymer monomer, the initiator, the lithium salt and the binder.

2. The solid-state battery according to claim 1, characterized in that The thickness of the first solid electrolyte layer is 5-70 μm.

3. The solid-state battery according to claim 1 or 2, characterized in that: The polymer electrolyte comprises at least one of polyethylene oxide, polyether polyol, polyphenylene ether, polyvinylidene fluoride-hexafluoropropylene and modified polyethylene oxide; Optionally, the first solid electrolyte layer further comprises the lithium salt.

4. The solid-state battery according to claim 3, characterized in that Based on the total mass of the first solid electrolyte layer, the polymer electrolyte accounts for no less than 85%.

5. The solid-state battery according to claim 1, characterized in that The thickness of the second solid electrolyte layer is 30-200 μm.

6. The solid-state battery according to claim 1 or 5, characterized in that: The mass ratio of the inorganic solid electrolyte, the polymer monomer, the initiator, the binder and the lithium salt is (20-80): (5-40): (0.1-5): (5-20): (1-10); Optionally, the inorganic solid electrolyte includes at least one of lithium aluminum titanium phosphate, a doped and modified compound of lithium aluminum titanium phosphate, lithium aluminum germanium phosphate, a doped and modified compound of lithium aluminum germanium phosphate, lithium lanthanum zirconium oxide, a doped and modified compound of lithium lanthanum zirconium oxide, lithium lanthanum titanium oxide, a doped and modified compound of lithium lanthanum titanium oxide, lithium lanthanum zirconium oxide, and a doped and modified compound of lithium lanthanum zirconium oxide; Optionally, the polymer monomer includes at least one of vinyl vinyl sulfite, vinyl ethylene carbonate, methyl vinyl sulfone, ethyl vinyl sulfone, methyl methacrylate and vinyl acetate; Optionally, the initiator comprises a polymerization initiator, and the polymerization initiator comprises at least one of azobisisobutyronitrile, azobisisoheptanenitrile, dimethyl azobisisobutyrate, benzoyl peroxide, tert-butyl benzoyl peroxide, and methyl ethyl ketone peroxide; Optionally, the binder includes at least one of polyvinylidene fluoride, a polyether binder and polyacrylonitrile; Optionally, the lithium salt includes at least one of lithium perchlorate, lithium tetrafluoroborate, lithium hexafluoroarsenate, lithium hexafluorophosphate, lithium bis(trifluoromethylsulfonyl)imide, lithium bis(fluorosulfonyl)imide, lithium trifluoromethylsulfonate, lithium bis(oxalatoborate), and lithium difluorooxalatoborate.

7. The solid-state battery according to claim 1, characterized in that It further includes a separator, which is arranged between the positive electrode sheet and the negative electrode sheet.

8. A method for preparing a solid-state battery according to any one of claims 1 to 7, characterized in that: include: A first solid electrolyte layer is formed on both sides of the negative electrode sheet; Alternately stacking the negative electrode sheets and the positive electrode sheets to obtain a pole core; After the electrode core is encapsulated with an aluminum-plastic film or placed in a shell, a prepolymer solution is injected to form a second solid electrolyte layer between the first solid electrolyte layer and the positive electrode plate, wherein the prepolymer solution includes an inorganic solid electrolyte, a polymer monomer, an initiator, a binder and a lithium salt.

9. The method according to claim 8, characterized in that Before the negative electrode sheets and the positive electrode sheets are alternately stacked, separators are pre-arranged on both sides of the negative electrode sheets.

10. A vehicle, characterized in that: The vehicle comprises a solid-state battery according to any one of claims 1 to 7 or a solid-state battery obtained by the method according to claim 8 or 9.

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