Composite solid electrolyte, preparation method thereof and all-solid-state battery

Abstract

The invention relates to a composite solid electrolyte, a preparation method thereof and an all-solid-state battery. The composite solid electrolyte comprises a porous oxyfluoride solid electrolyte, and a sulfide solid electrolyte and / or a halide solid electrolyte filled in pores of the porous oxyfluoride solid electrolyte, the preparation method comprises the following steps: preparing a porous oxyfluoride solid electrolyte by a template method, and filling sulfide solid electrolyte and / or halide solid electrolyte in pores of the porous oxyfluoride solid electrolyte by a liquid phase impregnation method to obtain the composite solid electrolyte with relatively high ionic conductivity and electrochemical window. The composite solid electrolyte is placed in a mold to be subjected to cold pressing to form a composite solid electrolyte sheet, and then the composite solid electrolyte sheet is placed between a positive pole piece and a negative pole piece to be subjected to hot pressing treatment to obtain the all-solid-state battery. The all-solid-state battery containing the composite solid electrolyte disclosed by the invention has relatively good cycle performance.

Description

Technical Field

[0001] This invention relates to the field of solid-state battery materials technology, and in particular to a composite solid-state electrolyte, its preparation method, and an all-solid-state battery. Background Technology

[0002] The industrialization of solid-state batteries is severely constrained by the inherent limitations of electrolyte material systems. While mainstream oxide electrolytes, such as oxide solid electrolytes, possess excellent environmental stability, their extremely high Young's modulus leads to rigid contact with electrode materials, resulting in significant interfacial impedance. On the other hand, sulfide electrolytes, despite their superior ionic conductivity, suffer from the dual challenges of high water and oxygen sensitivity, poor environmental stability, and low mechanical strength. These factors pose serious challenges to the environmental requirements of sulfide electrolyte production and the safety of batteries containing sulfide electrolytes.

[0003] In recent years, although various composite strategies have emerged to improve the aforementioned bottlenecks, most solutions have struggled to enhance one performance characteristic without sacrificing other key performance indicators. The key to overcoming these bottlenecks lies in designing an innovative structure and integrated process that can fundamentally synergize the advantages of different materials. Summary of the Invention

[0004] The purpose of this invention is to address the deficiencies of existing technologies by providing a composite solid electrolyte, its preparation method, and an all-solid-state battery.

[0005] To achieve the above objectives, in a first aspect, the present invention provides a composite solid electrolyte comprising: a porous fluoride solid electrolyte, and a sulfide solid electrolyte and / or a halide solid electrolyte filling the pores of the porous fluoride solid electrolyte.

[0006] Preferably, the porous fluoride solid electrolyte has the following general chemical formula:

[0007] Li x La y M1 a M2 b M3 c O6F, where M1 is a tetravalent cation, M2 is a pentavalent cation, M3 is a hexavalent cation, and x, y, a, b, and c are the molar percentages of the corresponding elements, and 1 < x + 3y < 5, 0 < x ≤ 2, 1 / 3 < y < 5 / 3, 0 ≤ a ≤ 2, 0 ≤ b ≤ 2, 0 ≤ c ≤ 2, and a + b + c = 2;

[0008] The porous fluoride solid electrolyte has a porosity of 20% to 50% and a pore size of 0.1 μm to 1 μm.

[0009] The porous fluoride oxide solid electrolyte accounts for 60% to 72% of the total mass of the composite solid electrolyte;

[0010] The sulfide solid electrolyte includes: Li2S-P2S5, Li7P3S 11 Li 10 GeP2S 12 One or more of Li6PS5Cl;

[0011] The halide solid electrolyte includes one or more of the following: Li3YCl6, Li3YBr6, Li2ZrCl6, Li2MnCl4, and LiAlF4;

[0012] The particle size Dv50 of the composite solid electrolyte is 1μm to 50μm.

[0013] More preferably, the M1 element specifically includes one or more of Zr, Ti, Hf, Si, Ge, and Sn;

[0014] The M2 element specifically includes one or more of Nb, Sb, Bi, V, and Ta;

[0015] The M3 element specifically includes one or more of W, Cr, Mo, and Mn.

[0016] In a second aspect, the present invention provides a method for preparing the composite solid electrolyte described in the first aspect, the method comprising:

[0017] The preparation of porous fluoride solid electrolyte by template method includes: ball milling and mixing raw materials for preparing fluoride solid electrolyte and template agent with a first solvent to form a slurry; spray granulating the slurry to obtain precursor microspheres; subjecting the precursor microspheres to a first-stage sintering treatment in an air atmosphere to remove the template agent and solvent, followed by a second-stage sintering to allow the raw materials of the fluoride solid electrolyte to react and form a crystalline phase structure, thereby obtaining a porous fluoride solid electrolyte;

[0018] A composite solid electrolyte is obtained by filling the pores of the porous fluoride solid electrolyte with sulfide solid electrolyte and / or halide solid electrolyte using a liquid-phase impregnation method. The process includes: dissolving the sulfide solid electrolyte and / or the halide solid electrolyte in a second solvent to obtain a solution at an environment with a dew point less than -40°C; then adding the porous fluoride solid electrolyte to the solution and stirring thoroughly to allow the solution to penetrate into the pores of the porous fluoride solid electrolyte; and then baking the solution to obtain the composite solid electrolyte.

[0019] Preferably, the step of ball milling and mixing the raw materials and template agent for preparing the fluoride oxide solid electrolyte with the solvent to form a slurry specifically includes: weighing lithium source material, lanthanum source material, fluorine source material, and doped element material as raw materials according to the stoichiometric ratio of the fluoride oxide solid electrolyte; placing the raw materials, template agent, and solvent in the ball mill jar of a ball mill; and ball milling at a speed of 300 rpm to 800 rpm for 6 to 24 hours to form a slurry.

[0020] The general chemical formula of the fluoride oxide solid electrolyte is Li. x La y M1 a M2 b M3 c O6F, where M1 is a tetravalent cation, M2 is a pentavalent cation, M3 is a hexavalent cation, and x, y, a, b, and c are the molar percentages of the corresponding elements, and 1 < x + 3y < 5, 0 < x ≤ 2, 1 / 3 < y < 5 / 3, 0 ≤ a ≤ 2, 0 ≤ b ≤ 2, 0 ≤ c ≤ 2, and a + b + c = 2;

[0021] The lithium source material includes one or more of lithium carbonate, lithium hydroxide, lithium oxalate, lithium acetate, and lithium nitrate.

[0022] The lanthanum source material includes one or more of the following: lanthanum trioxide, lanthanum carbonate, lanthanum nitrate, lanthanum hydroxide, and lanthanum fluoride;

[0023] The fluorine source material includes: lithium fluoride;

[0024] The doped material includes one or more of the following: materials containing M1 element, materials containing M2 element, and materials containing M3 element;

[0025] The template agent includes one or more of polymethyl methacrylate (PMMA), polystyrene (PS), polylactic acid (PLA), and polyethylene glycol (PEG); the particle size Dv50 of the template agent is 0.1 μm to 1 μm.

[0026] The first solvent includes one or more of deionized water, anhydrous ethanol, and anhydrous acetonitrile.

[0027] More preferably, the M1 element specifically includes one or more of Zr, Ti, Hf, Si, Ge, and Sn;

[0028] The M2 element specifically includes one or more of Nb, Sb, Bi, V, and Ta;

[0029] The M3 element specifically includes one or more of W, Cr, Mo, and Mn;

[0030] The template agent accounts for 20% to 50% of the total mass of the raw materials;

[0031] The ball milling medium is zirconia balls; the mass ratio of the zirconia balls, the raw materials and template agent, and the solvent is 3-5:1-2:1-2.

[0032] Preferably, the equipment used for spray granulation is a spray dryer; the inlet temperature of the spray dryer is 150℃~250℃, and the outlet temperature is 60℃~120℃; the particle size Dv50 of the precursor microspheres is 1μm~50μm.

[0033] The first sintering process specifically includes: in an air atmosphere, the precursor microspheres are loosely spread in an alumina crucible and placed in a reaction device, and the reaction device is heated from room temperature to 300℃ to 500℃ at a heating rate of 1℃ / min to 10℃ / min, and held at that temperature for 1 hour to 12 hours to remove the template agent and solvent.

[0034] The second sintering process specifically includes heating the reaction equipment to 500°C to 1000°C at a heating rate of 1°C / min to 10°C / min in an air atmosphere, and holding it at that temperature for 1 hour to 12 hours, so that the raw materials of the fluorine oxide solid electrolyte react to form a crystalline structure and obtain a porous fluorine oxide solid electrolyte.

[0035] The reaction equipment includes any one of the following: box furnace, tube furnace, and pusher plate furnace.

[0036] Preferably, the sulfide solid electrolyte includes: Li2S-P2S5, Li7P3S 11 Li 10 GeP2S 12 One or more of Li6PS5Cl;

[0037] The halide solid electrolyte includes one or more of the following: Li3YCl6, Li3YBr6, Li2ZrCl6, Li2MnCl4, and LiAlF4;

[0038] The second solvent includes one or more of deionized water, anhydrous ethanol, and anhydrous acetonitrile;

[0039] The solid content of the solution is 20wt% to 50wt%.

[0040] The mass ratio of the sulfide solid electrolyte and / or the halide solid electrolyte to the porous fluoride solid electrolyte is 3-5:5-7.

[0041] The time for thorough stirring is 6 to 24 hours;

[0042] The baking equipment is a vacuum drying oven, the baking temperature is 50℃~80℃, and the baking time is 6 hours~24 hours.

[0043] Thirdly, the present invention provides an all-solid-state battery, the all-solid-state battery comprising the composite solid-state electrolyte described in the first aspect, or comprising the composite solid-state electrolyte obtained by the preparation method described in the second aspect.

[0044] Fourthly, the present invention provides a method for preparing the all-solid-state battery described in the third aspect, the method comprising: placing the composite solid-state electrolyte described in the first aspect in a mold and cold-pressing it at 300 MPa to 600 MPa to form a composite solid-state electrolyte sheet with a thickness of 5 μm to 50 μm; then placing the composite solid-state electrolyte sheet between a positive electrode and a negative electrode, and performing hot-pressing treatment at a temperature of 150°C to 250°C and a pressure of 200 MPa to 500 MPa to obtain an all-solid-state battery.

[0045] The present invention provides a composite solid electrolyte, its preparation method, and an all-solid-state battery, which have the following technical effects.

[0046] This invention prepares porous fluoride solid electrolytes using a template method. The porous fluoride solid electrolytes are then immersed in a solution containing sulfide solid electrolytes and / or halide solid electrolytes and stirred thoroughly to allow the solution to penetrate into the pores of the porous fluoride solid electrolytes. After baking, a composite solid electrolyte is obtained.

[0047] The composite solid electrolyte of this invention comprises a porous fluoride solid electrolyte forming a three-dimensional framework structure, with sulfide solid electrolytes and / or halide solid electrolytes filling the pores of the porous fluoride solid electrolyte. Because the fluoride solid electrolyte has high ionic conductivity (≥7 mS / cm), high mechanical strength (Young's modulus 100 GPa~200 GPa), and water and oxygen stability comparable to traditional oxide electrolytes, it can protect the sulfide and / or halide solid electrolytes. The sulfide and halide solid electrolytes, in turn, possess high ionic conductivity and good ductility. The composite solid electrolyte leverages the synergistic effect of fluoride solid electrolytes, sulfide solid electrolytes, and / or halide solid electrolytes to successfully construct a novel "rigid-flexible" composite structure. The porous fluoride solid electrolyte framework, together with the filled sulfide solid electrolyte and / or halide solid electrolyte, forms a "dual highway" for lithium-ion transport, ensuring that the composite electrolyte as a whole has extremely high ionic conductivity. The sensitive sulfide solid electrolyte inside the pores of the porous fluoride solid electrolyte provides ultimate protection, enabling the composite electrolyte to have environmental stability close to that of oxide solid electrolytes, greatly reducing the environmental requirements for storage and preparation processes, as well as stability during application.

[0048] The composite electrolyte provided by this invention is used to prepare all-solid-state batteries. First, the powdered composite electrolyte is cold-pressed into a sheet, and then placed between the positive electrode sheet and the negative electrode sheet for hot pressing. Under certain temperature and high pressure, the three-dimensional framework of the porous fluoride solid electrolyte provides rigid support, while the sulfide solid electrolyte and / or halide solid electrolyte in the pores effectively contact the electrode sheet by utilizing their extensibility, providing effective ion channels and reducing the interfacial impedance caused by solid-solid contact, thereby improving the cycle performance of the all-solid-state battery. Attached Figure Description

[0049] Figure 1 This is a flowchart illustrating the preparation method of the composite solid electrolyte provided in an embodiment of the present invention. Detailed Implementation

[0050] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0051] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0052] This invention provides a composite solid electrolyte, comprising: a porous fluoride solid electrolyte, and a sulfide solid electrolyte and / or a halide solid electrolyte filling the pores of the porous fluoride solid electrolyte.

[0053] The general chemical formula of the porous fluoride oxide solid electrolyte is Li. x La y M1 a M2 b M3 c In O6F, x, y, a, b, and c represent the molar percentages of the corresponding elements, where 1 < x + 3y < 5, 0 < x ≤ 2, 1 / 3 < y < 5 / 3, 0 ≤ a ≤ 2, 0 ≤ b ≤ 2, 0 ≤ c ≤ 2, and a + b + c = 2. Element M1 is a tetravalent cation, specifically including one or more of Zr, Ti, Hf, Si, Ge, and Sn. Element M2 is a pentavalent cation, specifically including one or more of Nb, Sb, Bi, V, and Ta. Element M3 is a hexavalent cation, specifically including one or more of W, Cr, Mo, and Mn.

[0054] The porosity of porous fluoride solid electrolytes is 20% to 50%, and can be any value within this range, such as 20%, 25%, 30%, 35%, 40%, 45%, 50%, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0055] The pore size of the porous fluoride solid electrolyte is 0.1 μm to 1 μm, and can be any value within this range, such as 0.1 μm, 0.2 μm, 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm, 1 μm, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0056] The percentage of the porous fluoride oxide solid electrolyte in the total mass of the composite solid electrolyte is 60% to 72%, and can be any value within this range, such as 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0057] The porous fluoride solid electrolyte Li used in this embodiment of the invention x La y M1 a M2 b M3 cO6F possesses high mechanical strength, high density, high purity, as well as high volumetric energy density, low internal resistance, and excellent ion conductivity. It also has a rigid structure with tunable elemental composition. By introducing diverse coordination environments through multivalent cation doping, it can form open channels that facilitate lithium-ion transport. At the same time, fluorine can further enhance the polarity and interfacial wettability of the material, improve the interfacial contact between the electrolyte and the electrode, and reduce interfacial impedance.

[0058] Sulfide solid electrolytes include: Li₂S-P₂S₅, Li₇P₃S 11 Li 10 GeP2S 12 One or more of Li6PS5Cl.

[0059] Halogenated solid electrolytes include one or more of the following: Li3YCl6, Li3YBr6, Li2ZrCl6, Li2MnCl4, and LiAlF4.

[0060] The particle size Dv50 of the composite solid electrolyte is 1μm to 50μm, and can be any value within this range, such as 1μm, 5μm, 10μm, 15μm, 20μm, 25μm, 30μm, 35μm, 40μm, 45μm, 50μm, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0061] In this invention, the particle size Dv50 of the composite solid electrolyte refers to the volume median particle size of the material, representing the particle size corresponding to 50% of the material's volume distribution, a meaning known in the art. The particle size Dv50 of the composite solid electrolyte provided in this embodiment can be determined using instruments and conventional methods known in the art. Specifically, 1g of material sample is weighed and added to 20ml of deionized water, then 50ul of a 1% (w / w) aqueous solution of ethyl phenyl polyethylene glycol dispersant is added. The mixture is sonicated for 5 minutes, and then the dispersion is added to a Mastersizer 3000 laser particle size analyzer from Malvern Instruments Ltd. for particle size determination. The Dv50 value is then read.

[0062] This invention provides a method for preparing a composite solid electrolyte. A porous fluoride solid electrolyte is prepared using a template method, and then a sulfide solid electrolyte and / or a halide solid electrolyte are filled into the pores of the porous fluoride solid electrolyte using a liquid-phase impregnation method to obtain the composite solid electrolyte. Figure 1 As shown, the specific steps include:

[0063] Step 110: The raw materials and template agent for preparing the fluorine oxide solid electrolyte are ball-milled and mixed with the first solvent to form a slurry.

[0064] Specifically, lithium source material, lanthanum source material, fluorine source material, and doped element material are weighed according to the stoichiometric ratio of the fluorine oxide solid electrolyte. The raw materials, template agent, and solvent are placed in the ball mill jar of a ball mill and ball milled at a speed of 300 rpm to 800 rpm for 6 to 24 hours to form a slurry.

[0065] Among them, the general chemical formula of the fluoride oxide solid electrolyte is Li. x La y M1 a M2 b M3 c In O6F, x, y, a, b, and c represent the molar percentages of the corresponding elements, where 1 < x + 3y < 5, 0 < x ≤ 2, 1 / 3 < y < 5 / 3, 0 ≤ a ≤ 2, 0 ≤ b ≤ 2, 0 ≤ c ≤ 2, and a + b + c = 2. Element M1 is a tetravalent cation, specifically including one or more of Zr, Ti, Hf, Si, Ge, and Sn. Element M2 is a pentavalent cation, specifically including one or more of Nb, Sb, Bi, V, and Ta. Element M3 is a hexavalent cation, specifically including one or more of W, Cr, Mo, and Mn.

[0066] The lithium source materials include one or more of the following: lithium carbonate (Li2CO3), lithium hydroxide (LiOH), lithium oxalate (Li2C2O4), lithium acetate (Li2CO3), and lithium nitrate (Li2CO3).

[0067] Lanthanum source materials include one or more of the following: lanthanum trioxide, lanthanum carbonate, lanthanum nitrate, lanthanum hydroxide, and lanthanum fluoride.

[0068] Fluorine source materials include: lithium fluoride (LiF).

[0069] Materials containing doped elements include one or more of the following: materials containing M1, materials containing M2, and materials containing M3.

[0070] The template agent includes one or more of polymethyl methacrylate (PMMA), polystyrene (PS), polylactic acid (PLA), and polyethylene glycol (PEG); the particle size Dv50 of the template agent is 0.1 μm to 1 μm.

[0071] The first solvent includes one or more of deionized water, anhydrous ethanol, and anhydrous acetonitrile.

[0072] The template agent accounts for 20% to 50% of the total mass of the raw materials.

[0073] The ball milling medium is zirconia balls; the mass ratio of the total mass of zirconia balls, raw materials and template agent to the mass of solvent is 3-5:1-2:1-2.

[0074] Step 120: The slurry is spray-granulated to obtain precursor microspheres.

[0075] The equipment used for spray granulation is a spray dryer; the inlet temperature of the spray dryer is 150℃~250℃, and the outlet temperature is 60℃~120℃; the particle size Dv50 of the precursor microspheres is 1μm~50μm.

[0076] Step 130: Under an air atmosphere, the precursor microspheres undergo a first-stage sintering treatment to remove the template agent and solvent, followed by a second-stage sintering to allow the raw materials of the fluorine oxide solid electrolyte to react and form a crystalline structure, thereby obtaining a porous fluorine oxide solid electrolyte.

[0077] The first sintering process specifically includes: in an air atmosphere, the precursor microspheres are loosely spread in an alumina crucible and placed in a reaction device, and the reaction device is heated from room temperature to 300℃ to 500℃ at a heating rate of 1℃ / min to 10℃ / min, and held at that temperature for 1 hour to 12 hours to remove the template agent and solvent.

[0078] The second sintering process specifically includes heating the reaction equipment to 500℃ to 1000℃ in an air atmosphere at a heating rate of 1℃ / min to 10℃ / min, and holding it at that temperature for 1 hour to 12 hours, so that the raw materials of the fluorine oxide solid electrolyte react to form a crystalline structure and obtain a porous fluorine oxide solid electrolyte.

[0079] The reaction equipment includes any one of the following: box furnace, tube furnace, and pusher plate furnace.

[0080] Step 140: Under an environment with a dew point less than -40°C, dissolve the sulfide solid electrolyte and / or halide solid electrolyte in a second solvent to obtain a solution. Then, add the porous fluoride solid electrolyte to the solution and stir thoroughly to allow the solution to penetrate into the pores of the porous fluoride solid electrolyte. After baking, a composite solid electrolyte is obtained.

[0081] Among them, sulfide solid electrolytes include: Li2S-P2S5, Li7P3S 11 Li 10 GeP2S 12 One or more of Li6PS5Cl.

[0082] Halogenated solid electrolytes include one or more of the following: Li3YCl6, Li3YBr6, Li2ZrCl6, Li2MnCl4, and LiAlF4.

[0083] The particle size of sulfide solid electrolytes and / or halide solid electrolytes is less than or equal to the particle size of the template agent.

[0084] The mass ratio of sulfide solid electrolyte and / or halide solid electrolyte to porous fluoride solid electrolyte is 3–5:5–7, and can be any mass ratio within this range, such as 3:7, 3:6, 3:5, 4:7, 4:6, 4:5, 5:6, 5:7, 1:1, etc., but is not limited to the listed mass ratios; other unlisted mass ratios within this range are also applicable. The preferred mass ratio of sulfide solid electrolyte and / or halide solid electrolyte to porous fluoride solid electrolyte is 1:1.

[0085] The second solvent includes one or more of deionized water, anhydrous ethanol, and anhydrous acetonitrile; the solid content of the solution is 20wt% to 50wt%.

[0086] The stirring time should be 6 to 24 hours.

[0087] The baking equipment is a vacuum drying oven, the baking temperature is 50℃~80℃, and the baking time is 6 hours~24 hours.

[0088] The composite solid electrolyte prepared by the preparation method provided in this embodiment of the invention can be used to prepare all-solid-state batteries.

[0089] The present invention provides a method for preparing the above-mentioned all-solid-state battery, comprising: placing the composite solid electrolyte provided in the present invention in a mold, and cold pressing it at 300 MPa to 600 MPa to form a composite solid electrolyte sheet with a thickness of 5 μm to 50 μm; then placing the composite solid electrolyte sheet between the positive electrode sheet and the negative electrode sheet, and hot pressing it at a temperature of 150°C to 250°C and a pressure of 200 MPa to 500 MPa to obtain an all-solid-state battery.

[0090] There are no special restrictions on the positive electrode sheet; any positive electrode sheet that can be used in solid-state batteries is acceptable. The positive electrode sheet is prepared using conventional methods. The active material of the positive electrode sheet includes any one of the following: positive electrode sheets containing lithium cobalt oxide, positive electrode sheets containing ternary materials, positive electrode sheets containing lithium manganese oxide, and positive electrode sheets containing lithium iron phosphate. The ternary material can be NCM523, NCM622, NCM811, etc.

[0091] There are no special restrictions on the negative electrode sheet; any negative electrode sheet that can be used in solid-state batteries is acceptable. The negative electrode sheet is prepared using conventional methods. The negative electrode sheet includes any one of the following: lithium metal sheet, negative electrode sheet containing silicon-carbon negative electrode material, negative electrode sheet containing graphite, negative electrode sheet containing graphene, and negative electrode sheet containing transition metal.

[0092] To better understand the technical solution provided by the present invention, the preparation process and characteristics of the composite solid electrolyte of the present invention are illustrated below with several specific examples.

[0093] Example 1

[0094] This embodiment provides a process for preparing a composite solid electrolyte, and uses it to prepare an all-solid-state battery, and performs performance testing.

[0095] (1) According to the solid electrolyte of fluorine oxides Li 1.25 La 0.58 The stoichiometric ratio of Nb₂O₆F was determined by weighing 500g of Li₂CO₃, La₂O₃, Nb₂O₅, and LiF as raw materials. The raw materials, 0.25μm PMMA microspheres, and deionized water were placed in the ball mill jar and milled at 500rpm for 12 hours to form a uniform and stable slurry. The amount of PMMA microspheres used was 30wt% of the raw materials, and the mass ratio of zirconia microspheres, raw materials, PMMA microspheres, and deionized water was 3:1:1.

[0096] (2) The slurry was sprayed and granulated in a spray dryer. The inlet temperature was set to 180℃ and the outlet temperature was set to 80℃ to obtain precursor microspheres with good flowability and a particle size Dv50 of 10μm.

[0097] (3) Under air atmosphere, the precursor microspheres were loosely spread in an alumina crucible and placed in a tube furnace. The temperature of the reaction equipment was slowly increased from room temperature to 500°C at a heating rate of 5°C / min and held for 6 hours to remove the template agent and solvent. The temperature of the reaction equipment was then increased to 1000°C at a heating rate of 5°C / min and held for 6 hours to allow the raw materials of the fluorine oxide solid electrolyte to react and form a crystalline structure, thus obtaining the porous fluorine oxide solid electrolyte Li. 1.25 La 0.58 Nb2O6F.

[0098] (4) Under an environment with a dew point of less than -40°C, 50g of Li6PS5Cl powder was dissolved in 250g of anhydrous acetonitrile to obtain a solution. Then, 50g of porous fluoride solid electrolyte was added to the solution and stirred thoroughly for 12 hours to allow the solution to penetrate into the pores of the porous fluoride solid electrolyte. After that, it was transferred to a vacuum drying oven and baked at 80°C for 12 hours. Li6PS5Cl crystals precipitated and filled the pores of the porous fluoride solid electrolyte to obtain a composite solid electrolyte.

[0099] The ionic conductivity, surface resistivity, and electrochemical window of the composite solid electrolyte prepared in this embodiment were tested as follows.

[0100] Ionic conductivity and surface resistivity were measured using electrochemical impedance spectroscopy (EIS) on an electrochemical workstation.

[0101] First, the test battery was prepared. The composite solid electrolyte prepared in this embodiment was placed in a mold and cold-pressed at 300 MPa to form a composite solid electrolyte sheet with a thickness of 10 μm. This sheet was then sandwiched between two stainless steel (SS) inert electrodes to assemble the test battery, which was then connected to an electrochemical workstation for testing. To ensure the accuracy of the test, the test battery was placed in a constant temperature chamber for temperature control. In the EIS test, the frequency range was set from 0.01 Hz to 1 MHz, and the amplitude voltage was set to 10 mV to accurately measure the electrolyte resistance. Next, by analyzing the Nyquist impedance spectrum, the ionic conductivity of the electrolyte can be calculated using the following formula: In the determination of ionic conductivity, d in the formula represents the thickness of the composite solid electrolyte sheet between the stainless steel electrodes, R is the impedance value of the composite solid electrolyte sheet read from the Nyquist impedance diagram of EIS, and S represents the effective contact area between the solid electrolyte membrane and the stainless steel inert electrode. In this test, the composite solid electrolyte sheet and the stainless steel inert electrode are circular discs with a diameter of 17 mm. To ensure the accuracy of the measurement, when testing the ionic conductivity at different temperatures, the constant temperature chamber needs to be set to the target temperature and maintained for half an hour to allow the test battery to reach thermal equilibrium. This step ensures the stability of the test environment, thereby allowing for accurate measurement of ionic conductivity.

[0102] The surface resistance is calculated using the formula: Surface resistance = Impedance value R × Area S of the composite solid electrolyte sheet.

[0103] All ionic conductivity tests in this invention were conducted at 25±2℃ and humidity less than 50%. Detailed test data are shown in Table 1.

[0104] Electrochemical window testing was conducted using lithium metal sheets as both the reference and counter electrodes, while stainless steel sheets (SS) were used as the working electrode.

[0105] First, a lithium / stainless steel (Li|SS) battery was prepared. The composite solid electrolyte prepared in this embodiment was placed in a mold and cold-pressed at 300 MPa to form a composite solid electrolyte sheet with a thickness of 10 μm. This sheet was then cut into circular pieces with a diameter of 17 mm and sandwiched between a lithium metal sheet and a stainless steel (SS) sheet, assembling the lithium / stainless steel (Li|SS) battery in a glove box. Subsequently, linear sweep voltammetry (LSV) tests were performed in a constant temperature oven at room temperature. During the test, the scan rate was set to 1 mV / s, scanning from the open-circuit voltage to 6 V, measuring the electrochemical window. The test results are detailed in Table 1.

[0106] The composite solid-state electrolyte prepared in this embodiment was used to prepare an all-solid-state battery and a cycle test was performed, as detailed below.

[0107] Preparation of all-solid-state battery: Take an appropriate amount of the composite solid electrolyte provided in the embodiment of the present invention and place it in a mold. Cold press it into a composite solid electrolyte sheet with a thickness of 10 μm at 300 MPa. Then, sandwich the composite solid electrolyte sheet between a commercial lithium cobalt oxide positive electrode sheet and a commercial graphite negative electrode sheet. Perform hot pressing treatment at a temperature of 200°C and a pressure of 300 MPa to obtain an all-solid-state battery.

[0108] The prepared all-solid-state battery underwent cycle testing, specifically: 200 cycles were performed at a 1C current density using a blue electric current meter. The cycle capacity retention results are detailed in Table 1.

[0109] Example 2

[0110] This embodiment provides a preparation process for a composite solid-state electrolyte, and demonstrates its use in preparing an all-solid-state battery, followed by performance testing. The difference from Embodiment 1 is that the porous fluoride oxide solid-state electrolyte used is Li. 1.25 La 0.58 Ta2O6F.

[0111] (1) According to the solid electrolyte of fluorine oxides Li 1.25 La 0.58 To prepare Ta2O6F, 500g of a mixture of Li2CO3, La2O3, Ta2O5, and LiF was weighed as raw material. The raw material, along with 0.25μm PMMA microspheres and deionized water, were placed in a ball mill jar. Zirconia balls were used to mill the mixture at 500rpm for 12 hours to form a uniform and stable slurry. The amount of PMMA microspheres used was 30wt% of the raw material, and the mass ratio of zirconia balls, raw material, PMMA microspheres, and deionized water was 3:1:1.

[0112] (2) The slurry was sprayed and granulated in a spray dryer. The inlet temperature was set to 180℃ and the outlet temperature was set to 80℃ to obtain precursor microspheres with good flowability and a particle size Dv50 of 10μm.

[0113] (3) The preparation process is the same as in Example 1, and the obtained product is a porous fluoride oxide solid electrolyte Li. 1.25 La 0.58 Ta2O6F.

[0114] (4) Under an environment with a dew point of less than -40°C, 50g of Li6PS5Cl powder was dissolved in 250g of anhydrous acetonitrile to obtain a solution. Then, 50g of porous fluoride oxide solid electrolyte was added to the solution and stirred thoroughly for 12 hours to allow the solution to penetrate into the pores of the porous fluoride oxide solid electrolyte. Then, it was transferred to a vacuum drying oven and baked at 80°C for 12 hours to obtain a composite solid electrolyte.

[0115] The ionic conductivity, surface resistance, and electrochemical window of the composite solid electrolyte prepared in this embodiment were tested using the same testing method as in Example 1. The test data are detailed in Table 1.

[0116] All-solid-state batteries were prepared using the composite solid-state electrolyte prepared in this embodiment and subjected to cycle testing. The battery preparation and testing process was the same as in Example 1, and the test data are detailed in Table 1.

[0117] Example 3

[0118] This embodiment provides a process for preparing a composite solid electrolyte, and uses it to prepare an all-solid-state battery, and performs performance testing.

[0119] The difference from Example 1 lies in step (1), which follows the method of using the fluorine oxide solid electrolyte Li 1.25 La 0.58 The stoichiometric ratio of Nb₂O₆F was determined by weighing 500g of Li₂CO₃, La₂O₃, Nb₂O₅, and LiF as raw materials. The raw materials, 0.25μm PMMA microspheres, and deionized water were placed in the ball mill jar and milled at 800rpm for 8 hours to form a uniform and stable slurry. The amount of PMMA microspheres used was 30wt% of the raw materials, and the mass ratio of zirconia microspheres, raw materials, PMMA microspheres, and deionized water was 5:2:2.

[0120] Steps (2) to (4) are the same as in Example 1.

[0121] The ionic conductivity, surface resistance, and electrochemical window of the composite solid electrolyte prepared in this embodiment were tested using the same testing method as in Example 1. The test data are detailed in Table 1.

[0122] All-solid-state batteries were prepared using the composite solid-state electrolyte prepared in this embodiment and subjected to cycle testing. The battery preparation and testing process was the same as in Example 1, and the test data are detailed in Table 1.

[0123] Example 4

[0124] This embodiment provides a process for preparing a composite solid electrolyte, and uses it to prepare an all-solid-state battery, and performs performance testing.

[0125] (1) The slurry preparation process is the same as in Example 1.

[0126] (2) The slurry was sprayed and granulated in a spray dryer. The inlet temperature was set to 200℃ and the outlet temperature was set to 100℃ to obtain precursor microspheres with good flowability and a particle size Dv50 of 20μm.

[0127] The preparation process in steps (3) to (4) is the same as in Example 1.

[0128] The ionic conductivity, surface resistance, and electrochemical window of the composite solid electrolyte prepared in this embodiment were tested using the same testing method as in Example 1. The test data are detailed in Table 1.

[0129] All-solid-state batteries were prepared using the composite solid-state electrolyte prepared in this embodiment and subjected to cycle testing. The battery preparation and testing process was the same as in Example 1, and the test data are detailed in Table 1.

[0130] Example 5

[0131] This embodiment provides a process for preparing a composite solid electrolyte, and uses it to prepare an all-solid-state battery, and performs performance testing.

[0132] The difference from Example 1 lies in step (3). In an air atmosphere, the precursor microspheres are loosely spread in an alumina crucible and placed in a tube furnace. The reaction equipment is slowly heated from room temperature to 400°C at a heating rate of 3°C / min and held for 10 hours to remove the template agent and solvent. The reaction equipment is then heated to 900°C at a heating rate of 7°C / min and held for 10 hours to allow the raw materials of the fluorine oxide solid electrolyte to react and form a crystalline structure, thus obtaining a porous fluorine oxide solid electrolyte Li. 1.25 La 0.58 Nb2O6F.

[0133] The other preparation processes are the same as in Example 1.

[0134] The ionic conductivity, surface resistance, and electrochemical window of the composite solid electrolyte prepared in this embodiment were tested using the same testing method as in Example 1. The test data are detailed in Table 1.

[0135] All-solid-state batteries were prepared using the composite solid-state electrolyte prepared in this embodiment and subjected to cycle testing. The battery preparation and testing process was the same as in Example 1, and the test data are detailed in Table 1.

[0136] Example 6

[0137] This embodiment provides a preparation process for a composite solid electrolyte, and demonstrates the use of it to prepare an all-solid-state battery, followed by performance testing. The difference from Embodiment 1 lies in the different types of fluorine oxide and sulfide solid electrolytes used, as well as the different process step (4), as detailed below.

[0138] (1) According to the solid electrolyte of fluorine oxides Li 1.25 La 0.58 The stoichiometric ratio of NbTiO6F was determined by weighing 500g of Li2CO3, La2O3, Nb2O5, TiO2, and LiF as raw materials. The raw materials, 0.25μm PMMA microspheres, and deionized water were placed in the ball mill jar and milled at 500rpm for 12 hours to form a uniform and stable slurry. The amount of PMMA microspheres used was 30wt% of the raw materials, and the mass ratio of zirconia microspheres, raw materials, PMMA microspheres, and deionized water was 3:1:1.

[0139] (2) The preparation process is the same as in Example 1.

[0140] (3) The preparation process is the same as in Example 1, yielding a porous fluoride oxide solid electrolyte Li. 1.25 La 0.58 NbTiO6F.

[0141] (4) In a dry room environment with a dew point less than -40℃, 50g of Li 10 GeP2S 12 The powder was dissolved in 125g of anhydrous acetonitrile to obtain a solution with a solid content of 40%. Then, 50g of porous fluoride oxide solid electrolyte was added to the solution and stirred thoroughly for 10 hours to allow the solution to penetrate into the pores of the porous fluoride oxide solid electrolyte. After that, it was transferred to a vacuum drying oven and baked at 70℃ for 8 hours. Li6PS5Cl crystals precipitated and filled the pores of the porous fluoride oxide solid electrolyte, thus obtaining a composite solid electrolyte.

[0142] The other preparation steps are the same as in Example 1.

[0143] The ionic conductivity, surface resistance, and electrochemical window of the composite solid electrolyte prepared in this embodiment were tested using the same testing method as in Example 1. The test data are detailed in Table 1.

[0144] All-solid-state batteries were prepared using the composite solid-state electrolyte prepared in this embodiment and subjected to cycle testing. The battery preparation and testing process was the same as in Example 1, and the test data are detailed in Table 1.

[0145] Example 7

[0146] This embodiment provides a preparation process for a composite solid electrolyte, which is the same as that in Example 1. The difference from Example 1 lies in the type of fluorine oxide solid electrolyte and sulfide solid electrolyte used, as detailed below.

[0147] (1) According to the solid electrolyte of fluorine oxides Li 1.25 La 0.58The stoichiometric ratio of Bi₂O₆F was determined by weighing 500g of Li₂CO₃, La₂O₃, Bi₂O₃, and LiF as raw materials. The raw materials, 0.25μm PMMA microspheres, and deionized water were placed in the ball mill jar. Zirconia balls were used to mill the mixture at 500rpm for 12 hours to form a uniform and stable slurry. The amount of PMMA microspheres used was 30wt% of the raw materials, and the mass ratio of zirconia balls, raw materials, PMMA microspheres, and deionized water was 3:1:1.

[0148] (2) The preparation process is the same as in Example 1.

[0149] (3) The preparation process is the same as in Example 1, yielding a porous fluoride oxide solid electrolyte Li. 1.25 La 0.58 Bi2O6F.

[0150] (4) Under an environment with a dew point of less than -40°C, 50g of Li3YCl6 powder was dissolved in 250g of anhydrous acetonitrile to obtain a solution. Then, 50g of porous fluoride oxide solid electrolyte was added to the solution and stirred thoroughly for 12 hours to allow the solution to penetrate into the pores of the porous fluoride oxide solid electrolyte. After that, it was transferred to a vacuum drying oven and baked at 80°C for 12 hours. Li3YCl6 crystals precipitated and filled the pores of the porous fluoride oxide solid electrolyte to obtain a composite solid electrolyte.

[0151] The prepared all-solid-state battery was subjected to cycle testing, and the testing process was the same as in Example 1. The test data are detailed in Table 1.

[0152] To better illustrate the effects of the embodiments of the present invention, a comparative example is provided to be made with the embodiments described above.

[0153] Comparative Example 1

[0154] This comparative example directly prepares the fluoride oxide solid electrolyte Li. 1.25 La 0.58 Nb2O6F was cold-pressed into sheets and assembled into all-solid-state batteries. The specific process is as follows.

[0155] 500g of Li₂CO₃, La₂O₃, Nb₂O₅, and LiF were mixed evenly and placed in a box furnace. The temperature was increased to 300℃ at a rate of 5℃ / min and held for 2 hours. Then, the temperature was increased to 1000℃ at a rate of 5℃ / min and held for 6 hours to obtain the precursor powder. After discharge, the powder was sieved to obtain Li₂F, a solid electrolyte of fluorine oxides with a particle size Dv₅₀ of 10μm. 1.25 La 0.58 Nb2O6F.

[0156] Take an appropriate amount of fluorine oxide solid electrolyte Li 1.25La 0.58 Nb2O6F powder was placed in a mold and cold-pressed at 300 MPa to form a solid electrolyte sheet with a thickness of 10 μm. The solid electrolyte sheet was then sandwiched between a commercial lithium cobalt oxide positive electrode and a commercial graphite negative electrode and hot-pressed at 200°C and 300 MPa to obtain an all-solid-state battery.

[0157] The fluoride oxide solid electrolyte Li prepared in this comparative example was tested. 1.25 La 0.58 The ionic conductivity, surface resistivity, and electrochemical window of Nb2O6F were tested using the same methods as in Example 1, and the test data are detailed in Table 1.

[0158] The solid electrolyte Li containing fluorine oxides prepared in this comparative example 1.25 La 0.58 The Nb2O6F all-solid-state battery was tested for cycling, and the testing process was the same as in Example 1. The test data are detailed in Table 1.

[0159] Comparative Example 2

[0160] This comparative example directly uses the sulfide solid electrolyte Li6PS5Cl powder used in Example 1, which is cold-pressed into a finished product and assembled into an all-solid-state battery. The specific process is as follows.

[0161] An appropriate amount of Li6PS5Cl powder was placed in a mold and cold-pressed at 300 MPa to form a solid electrolyte sheet with a thickness of 10 μm. The solid electrolyte sheet was then sandwiched between a commercial lithium cobalt oxide positive electrode and a commercial graphite negative electrode and hot-pressed at 200℃ and 300 MPa to obtain an all-solid-state battery.

[0162] The ionic conductivity, surface resistivity, and electrochemical window of the comparative example sulfide solid electrolyte Li6PS5Cl were tested using the same method as in Example 1. The test data are detailed in Table 1.

[0163] All-solid-state batteries with sulfide solid electrolyte Li6PS5Cl were subjected to cycle tests. The test process was the same as in Example 1, and the test data are detailed in Table 1.

[0164] Comparative Example 3

[0165] This comparative example provides a method for preparing a composite solid electrolyte, which differs from Example 1 in that it does not add the template agent PMMA, i.e., it does not prepare a porous fluoride oxide solid electrolyte Li. 1.25 La 0.58 Nb2O6F, directly Li 1.25 La 0.58Nb₂O₆F and Li₆PS₅Cl were mixed at a mass ratio of 1:1 and placed in a mold. The mixture was then cold-pressed at 300 MPa to form a composite solid electrolyte sheet with a thickness of 10 μm. The composite solid electrolyte sheet was then sandwiched between a commercial lithium cobalt oxide positive electrode and a commercial graphite negative electrode and hot-pressed at 200 °C and 300 MPa to obtain an all-solid-state battery.

[0166] The ionic conductivity, surface resistance, and electrochemical window of the composite solid electrolyte prepared in this comparative example were tested using the same methods as in Example 1. The test data are detailed in Table 1.

[0167] The all-solid-state battery prepared in this comparative example was subjected to cycle testing. The testing process was the same as in Example 1, and the test data are detailed in Table 1.

[0168] Table 1 summarizes the test data for Examples 1-7 and Comparative Examples 1-3.

[0169]

[0170]

[0171] Table 1

[0172] As can be seen from the comparison of the test data in Table 1, the ionic conductivity of Examples 1-7 is much higher than that of Comparative Example 1, the sheet resistance of Examples 1-7 is significantly lower than that of Comparative Example 1, the electrochemical window of Examples 1-7 is significantly higher than that of Comparative Examples 1-3, and the capacity retention rate of Examples 1-7 after 200 cycles is significantly higher than that of Comparative Examples 1-3.

[0173] This is because Comparative Example 1 did not adopt the composite scheme of the present invention, but directly used fluorine oxide solid electrolyte to prepare solid electrolyte sheets by cold pressing. Due to its high Young's modulus, there are gaps between the particles under cold pressing, which seriously affects the bulk conduction of ions. Therefore, the ionic conductivity, sheet resistance and electrochemical window of Comparative Example 1 are low, and it is also difficult to form a film with a large interfacial impedance, which makes the all-solid-state battery unable to operate.

[0174] Comparative Example 2 directly prepared solid electrolyte sheets by cold pressing sulfide solid electrolytes. Although sulfide solid electrolytes have the characteristics of high ionic conductivity and low surface resistance, their instability makes them prone to side reactions between the positive and negative electrodes, leading to battery failure. Therefore, the all-solid-state battery in the comparative example failed after 30 cycles.

[0175] In Comparative Example 3, the non-porous fluoride solid electrolyte was directly combined with the sulfide solid electrolyte, which could not be efficiently matched with the sulfide solid electrolyte with high ionic conductivity. The protection of the unstable sulfide solid electrolyte was limited, thus affecting the electrochemical performance of the final composite solid electrolyte. Therefore, the ionic conductivity and electrochemical window of Comparative Example 3 were smaller than those of Example 1, while the sheet resistance was larger than that of Example 1. The cycle capacity retention rate of the prepared all-solid battery was smaller than that of Example 1. However, the cycle performance of the all-solid battery of Comparative Example 3 was better than that of Example 2, indicating that the stability of the solid electrolyte after composite in Comparative Example 3 was better than that of the single sulfide solid electrolyte in Comparative Example 2.

[0176] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A composite solid electrolyte, characterized in that, The composite solid electrolyte comprises: a porous fluoride solid electrolyte, and a sulfide solid electrolyte and / or a halide solid electrolyte filling the pores of the porous fluoride solid electrolyte.

2. The composite solid electrolyte according to claim 1, characterized in that, The porous fluoride solid electrolyte has the general chemical formula Li. x La y M1 a M2 b M3 c O6F, where M1 is a tetravalent cation, M2 is a pentavalent cation, M3 is a hexavalent cation, and x, y, a, b, and c are the molar percentages of the corresponding elements, and 1 < x + 3y < 5, 0 < x ≤ 2, 1 / 3 < y < 5 / 3, 0 ≤ a ≤ 2, 0 ≤ b ≤ 2, 0 ≤ c ≤ 2, and a + b + c = 2; The porous fluoride solid electrolyte has a porosity of 20% to 50% and a pore size of 0.1 μm to 1 μm. The porous fluoride oxide solid electrolyte accounts for 60% to 72% of the total mass of the composite solid electrolyte; The sulfide solid electrolyte includes: Li2S-P2S5, Li7P3S 11 Li 10 GeP2S 12 One or more of Li6PS5Cl; The halide solid electrolyte includes one or more of the following: Li3YCl6, Li3YBr6, Li2ZrCl6, Li2MnCl4, and LiAlF4; The particle size Dv50 of the composite solid electrolyte is 1μm to 50μm.

3. The composite solid electrolyte according to claim 2, characterized in that, The M1 element specifically includes one or more of Zr, Ti, Hf, Si, Ge, and Sn; The M2 element specifically includes one or more of Nb, Sb, Bi, V, and Ta; The M3 element specifically includes one or more of W, Cr, Mo, and Mn.

4. A method for preparing the composite solid electrolyte according to any one of claims 1-3, characterized in that, The preparation method includes: The preparation of porous fluoride solid electrolyte by template method includes: ball milling and mixing raw materials for preparing fluoride solid electrolyte and template agent with a first solvent to form a slurry; spray granulating the slurry to obtain precursor microspheres; subjecting the precursor microspheres to a first-stage sintering treatment in an air atmosphere to remove the template agent and solvent, followed by a second-stage sintering to allow the raw materials of the fluoride solid electrolyte to react and form a crystalline phase structure, thereby obtaining a porous fluoride solid electrolyte; A composite solid electrolyte is obtained by filling the pores of the porous fluoride solid electrolyte with sulfide solid electrolyte and / or halide solid electrolyte using a liquid-phase impregnation method. The process includes: dissolving the sulfide solid electrolyte and / or the halide solid electrolyte in a second solvent to obtain a solution at an environment with a dew point less than -40°C; then adding the porous fluoride solid electrolyte to the solution and stirring thoroughly to allow the solution to penetrate into the pores of the porous fluoride solid electrolyte; and then baking the solution to obtain the composite solid electrolyte.

5. The preparation method according to claim 4, characterized in that, The process of ball milling and mixing the raw materials and template agent for preparing fluorine oxide solid electrolyte with solvent to form a slurry specifically includes: weighing lithium source material, lanthanum source material, fluorine source material, and doped element material as raw materials according to the stoichiometric ratio of fluorine oxide solid electrolyte; placing the raw materials, template agent, and solvent in the ball mill jar of a ball mill; and ball milling at a speed of 300 rpm to 800 rpm for 6 to 24 hours to form a slurry. The general chemical formula of the fluoride oxide solid electrolyte is Li. x La y M1 a M2 b M3 c O6F, where M1 is a tetravalent cation, M2 is a pentavalent cation, M3 is a hexavalent cation, and x, y, a, b, and c are the molar percentages of the corresponding elements, and 1 < x + 3y < 5, 0 < x ≤ 2, 1 / 3 < y < 5 / 3, 0 ≤ a ≤ 2, 0 ≤ b ≤ 2, 0 ≤ c ≤ 2, and a + b + c = 2; The lithium source material includes one or more of lithium carbonate, lithium hydroxide, lithium oxalate, lithium acetate, and lithium nitrate. The lanthanum source material includes one or more of the following: lanthanum trioxide, lanthanum carbonate, lanthanum nitrate, lanthanum hydroxide, and lanthanum fluoride; The doped material includes one or more of the following: materials containing M1 element, materials containing M2 element, and materials containing M3 element; The fluorine source material includes: lithium fluoride; The template agent includes one or more of polymethyl methacrylate (PMMA), polystyrene (PS), polylactic acid (PLA), and polyethylene glycol (PEG); the particle size Dv50 of the template agent is 0.1 μm to 1 μm. The first solvent includes one or more of deionized water, anhydrous ethanol, and anhydrous acetonitrile.

6. The preparation method according to claim 5, characterized in that, The M1 element specifically includes one or more of Zr, Ti, Hf, Si, Ge, and Sn; The M2 element specifically includes one or more of Nb, Sb, Bi, V, and Ta; The M3 element specifically includes one or more of W, Cr, Mo, and Mn; The template agent accounts for 20% to 50% of the total mass of the raw materials; The ball milling medium is zirconia balls; the mass ratio of the zirconia balls, the raw materials and template agent, and the solvent is 3-5:1-2:1-2.

7. The preparation method according to claim 4, characterized in that, The equipment used for spray granulation is a spray dryer; the inlet temperature of the spray dryer is 150℃~250℃, and the outlet temperature is 60℃~120℃; the particle size Dv50 of the precursor microspheres is 1μm~50μm. The first sintering process specifically includes: in an air atmosphere, the precursor microspheres are loosely spread in an alumina crucible and placed in a reaction device, and the reaction device is heated from room temperature to 300℃ to 500℃ at a heating rate of 1℃ / min to 10℃ / min, and held at that temperature for 1 hour to 12 hours to remove the template agent and solvent. The second sintering process specifically includes heating the reaction equipment to 500°C to 1000°C at a heating rate of 1°C / min to 10°C / min in an air atmosphere, and holding it at that temperature for 1 hour to 12 hours, so that the raw materials of the fluorine oxide solid electrolyte react to form a crystalline structure and obtain a porous fluorine oxide solid electrolyte. The reaction equipment includes any one of the following: box furnace, tube furnace, and pusher plate furnace.

8. The preparation method according to claim 4, characterized in that, The sulfide solid electrolyte includes: Li2S-P2S5, Li7P3S 11 Li 10 GeP2S 12 One or more of Li6PS5Cl; The halide solid electrolyte includes one or more of the following: Li3YCl6, Li3YBr6, Li2ZrCl6, Li2MnCl4, and LiAlF4; The second solvent includes one or more of deionized water, anhydrous ethanol, and anhydrous acetonitrile; The solid content of the solution is 20wt% to 50wt%. The mass ratio of the sulfide solid electrolyte and / or the halide solid electrolyte to the porous fluoride solid electrolyte is 3-5:5-7. The time for thorough stirring is 6 to 24 hours; The baking equipment is a vacuum drying oven, the baking temperature is 50℃~80℃, and the baking time is 6 hours~24 hours.

9. An all-solid-state battery, characterized in that, The all-solid-state battery includes the composite solid-state electrolyte as described in any one of claims 1-3, or the composite solid-state electrolyte obtained by the preparation method described in any one of claims 4-8.

10. A method for preparing an all-solid-state battery according to claim 9, characterized in that, The method for preparing the all-solid-state battery includes: placing the composite solid electrolyte as described in any one of claims 1-3 in a mold and cold-pressing it into a composite solid electrolyte sheet with a thickness of 5μm to 50μm at 300MPa to 600MPa; then placing the composite solid electrolyte sheet between the positive electrode and the negative electrode and performing hot-pressing treatment at a temperature of 150℃ to 250℃ and a pressure of 200MPa to 500MPa to obtain the all-solid-state battery.

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