Sodium-ion solid-state battery and preparation method and application thereof

Abstract

The invention relates to the technical field of sodium-ion solid-state batteries, in particular to a sodium-ion solid-state battery and a preparation method and application thereof. The sodium-ion solid-state battery comprises a composite solid-state electrolyte, the composite solid electrolyte is prepared from sodium beta-aluminum oxide (Na [beta]-Al2O3) grafted polyaniline. The polyaniline forms a chemically bonded grafting structure in pore channels of the sodium beta-alumina, so that the composite solid electrolyte has high conductivity, the stability of an interface between the composite solid electrolyte and an electrode material is high, and the sodium ion solid-state battery has high charge-discharge capacity and rate capability.

Description

Technical Field

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

[0002] A sodium-ion solid-state battery is a new type of battery that uses a solid electrolyte to replace the traditional liquid electrolyte to achieve efficient transmission of sodium ions between the positive and negative electrodes, thereby replacing the flammable organic electrolyte and separator in the traditional liquid sodium-ion battery. Sodium-ion solid-state batteries have been widely promoted and used because of their excellent chemical stability and thermal stability. However, at present, the ionic conductivity of the solid electrolyte in sodium-ion solid-state batteries is generally lower than that of the liquid electrolyte, thus limiting the rate performance and practical applications of the batteries; moreover, the interfacial stability between the solid electrolyte and the electrode material is poor, which will lead to a relatively fast capacity decay of the battery. Summary of the Invention

[0003] To solve the above problems, the present invention provides a sodium-ion solid-state battery, a preparation method thereof, and an application thereof. At least one aspect of the above technical problems is solved.

[0004] The present invention is achieved through the following technical solutions: In a first aspect, the present invention provides a sodium-ion solid-state battery, including a composite solid electrolyte; The composite solid electrolyte includes sodium β-alumina (Naβ-Al2O3) grafted with polyaniline.

[0005] In some possible implementation manners, the raw materials of the sodium β-alumina grafted with polyaniline include sodium β-alumina, aniline, and ammonium persulfate.

[0006] In some possible implementation manners, the mass ratio of the sodium β-alumina, the aniline, and the ammonium persulfate is 1:(3-6):1.

[0007] In some possible implementation manners, the sodium β-alumina has a porous structure.

[0008] In some possible implementation manners, the porosity of the sodium β-alumina is 30% - 50%.

[0009] In some possible implementation manners, the pore diameter of the sodium β-alumina is 1 μm - 5 μm.

[0010] In a second aspect, the present invention provides a preparation method of the above sodium-ion solid-state battery, including the following steps: Prepare a composite solid electrolyte.

[0011] In some possible implementation manners, the preparation of the composite solid electrolyte includes the following steps: The acidified sodium β-alumina and aniline are subjected to a loading treatment to obtain sodium β-alumina grafted with aniline; The suspension of sodium β-alumina grafted with aniline is mixed with a sodium persulfate solution to obtain sodium β-alumina grafted with polyaniline.

[0012] In some possible implementation manners, the loading treatment includes the following steps: Under stirring conditions, the acidified sodium β-alumina and aniline are mixed and soaked and then air-dried.

[0013] In some possible implementation manners, the pH value of the suspension of sodium β-alumina grafted with aniline is below 2.

[0014] In some possible implementation manners, the mixing treatment includes the following steps: Under stirring conditions, the suspension of sodium β-alumina grafted with aniline and the sodium persulfate solution are mixed and then washed and dried.

[0015] In some possible implementation manners, the time for the mixing and soaking is 20 min to 30 min.

[0016] In some possible implementation manners, the time for the air-drying is 6 h to 12 h.

[0017] In some possible implementation manners, the steps of mixing, soaking, and air-drying are repeated 2 to 4 times.

[0018] In some possible implementation manners, the temperature of the suspension of sodium β-alumina grafted with aniline is 0 °C to 5 °C.

[0019] In some possible implementation manners, the temperature of the sodium persulfate solution is 0 °C to 5 °C.

[0020] In some possible implementation manners, the step of mixing the suspension of sodium β-alumina grafted with aniline and the sodium persulfate solution includes: The sodium persulfate solution is dropped into the suspension of sodium β-alumina grafted with aniline at a dropping rate of 30 drops / min to 60 drops / min.

[0021] In some possible implementation manners, the drying step includes: The washed product is vacuum-dried at 50 °C to 60 °C.

[0022] In a third aspect, the present invention provides an application of the above-mentioned sodium-ion solid-state battery in the new energy field.

[0023] The sodium-ion solid-state battery and its preparation method provided by the present invention, compared with the prior art, have at least the following beneficial technical effects: In the sodium-ion solid-state battery provided by the present invention, in the composite solid electrolyte thereof, polyaniline and sodium β-alumina have a graft structure with chemical bonding on the surface, so that the composite solid electrolyte has a very high conductivity, and the contact between the polyaniline on the surface and the electrode material is excellent, so that the interface stability is high, and further the sodium-ion solid-state battery has a very high charge-discharge capacity and rate performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present drawings or the prior art, the drawings required for use in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present drawings. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on the structures shown in these drawings.

[0025] Figure 1 Schematic diagram of the graft structure of the composite solid electrolyte provided by the embodiment of the present invention; Figure 2 Schematic diagram of the structure of the sodium-ion solid-state battery provided by the embodiment of the present invention; Figure 3 Cycling curve of the sodium-ion solid-state battery provided by Embodiment 1 of the present invention at 25°C.

[0026] Description of the reference numerals: 1 - sodium β-alumina pore channel, 2 - polyaniline, 3 - positive electrode plate, 4 - composite solid electrolyte, 5 - negative electrode plate.

[0027] The realization, functional features and advantages of the present drawings will be further described in conjunction with the embodiments with reference to the drawings. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0028] In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention will be described and illustrated below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. Based on the embodiments provided by the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0029] For those of ordinary skill in the art related to the content disclosed by the present invention, some designs, manufacturing or production changes based on the technical content disclosed by the present invention are only conventional technical means and should not be understood that the content disclosed by the present invention is insufficient.

[0030] Unless otherwise specified, all embodiments and optional embodiments of the present invention can be combined with each other to form new technical solutions, and all technical features and optional technical features of the present invention can be combined with each other to form new technical solutions.

[0031] In the first aspect of the embodiments of the present invention, a sodium-ion solid-state battery is provided. As Figure 1 shown, it includes a composite solid electrolyte; The composite solid electrolyte includes sodium beta-alumina (Naβ-Al2O3) grafted with polyaniline.

[0032] In the sodium-ion solid-state battery provided by the embodiments of the present invention, sodium beta-alumina (Naβ-Al2O3) grafted with polyaniline has a very high ionic conductivity, thereby improving the interface stability, charge-discharge capacity, and rate performance of the sodium-ion solid-state battery.

[0033] In some embodiments, the raw materials of sodium beta-alumina (Naβ-Al2O3) grafted with polyaniline include sodium beta-alumina, aniline, and ammonium persulfate.

[0034] In some embodiments, the mass ratio of sodium beta-alumina, aniline, and ammonium persulfate is 1:(3-6):1. In this case, aniline is in excess compared to ammonium persulfate, causing aniline not to fully polymerize, and the reaction generates emerald green imine salt, which has a very high conductivity.

[0035] In some embodiments, sodium beta-alumina has a porous structure. In this case, polyaniline forms a chemically bonded grafted structure in the pores of sodium beta-alumina.

[0036] In some embodiments, the porosity of sodium beta-alumina is 30% - 50%.

[0037] In some embodiments, the pore diameter of sodium beta-alumina is 1 μm - 5 μm.

[0038] In some embodiments, the CAS number of aniline is 62-53-3.

[0039] In some embodiments, a sodium-ion solid-state battery is provided. As Figure 2 shown, it includes a positive electrode plate 3, the above-mentioned composite solid electrolyte 4, and a negative electrode plate 5.

[0040] In some embodiments, in the positive electrode plate, the positive electrode active material includes at least one of NaNiO2, NaMnO2, NaNi 1 / 3 Fe 1 / 3 Mn 1 / 3O2, NaFePO4, Na3V2(PO4)3@C, Na2Fe2(SO4)3@C@GO, Na2FePO4F / C.

[0041] In some embodiments, the material of the negative electrode sheet includes a sodium sheet.

[0042] The second aspect of the embodiments of the present invention provides a method for preparing the above-mentioned sodium-ion solid-state battery, including the following steps: S10. Prepare a composite solid electrolyte.

[0043] In the method for preparing a sodium-ion solid-state battery provided by the embodiments of the present invention, when preparing the composite solid electrolyte, polyaniline is grafted onto the surface of sodium beta-alumina (Naβ-Al2O3), which increases the specific surface area of the electrolyte, thereby increasing the ionic conductivity of the solid electrolyte. Further, sodium beta-alumina grafted with polyaniline is in closer contact with the electrode material, thereby reducing the interfacial reaction between the solid electrolyte and the electrode material, and further improving the interfacial stability of the sodium-ion solid-state battery.

[0044] In some embodiments, in the above step S10, preparing the composite solid electrolyte includes the following steps: S101. Load the acidified sodium beta-alumina and aniline to obtain sodium beta-alumina grafted with aniline.

[0045] S102. Mix the suspension of sodium beta-alumina grafted with aniline with a sodium persulfate solution to obtain sodium beta-alumina grafted with polyaniline.

[0046] In the above steps for preparing the composite solid electrolyte, the sodium beta-alumina is acidified to graft aniline onto the surface of the sodium beta-alumina, and then oxidized and polymerized with ammonium sulfate to obtain sodium beta-alumina (Naβ-Al2O3) grafted with polyaniline.

[0047] In some embodiments, in the above step S101, the preparation steps of the acidified sodium beta-alumina include: S1011. Mix and acidify the sodium beta-alumina and a dilute acid solution, and then wash and dry.

[0048] In the above steps for acidifying the sodium beta-alumina, after mixing and acidifying the sodium beta-alumina and the dilute acid solution, it is washed to remove the free acid on the surface of the sodium beta-alumina, and dried to remove the washing solvent on the surface.

[0049] In some embodiments, in the above step S1011, the dilute acid solution is dilute hydrochloric acid, dilute sulfuric acid or dilute nitric acid. In this case, the dilute acid solution can quickly acidify the sodium beta-alumina.

[0050] In some embodiments, in the above step S1011, the concentration of the dilute acid solution is 0.1 mol / L to 1 mol / L.

[0051] In some embodiments, in the above step S1011, the temperature of the mixed acidification is 60°C to 70°C.

[0052] In some embodiments, in the above step S1011, the time of the mixed acidification is 6 h to 8 h.

[0053] In some embodiments, in the above step S1011, the washing step includes: Washing sodium β-alumina with water until neutral.

[0054] In some embodiments, in the above step S1011, the drying temperature is 90°C to 100°C. In this case, this temperature removes the residual moisture on the surface of the sodium β-alumina after water washing.

[0055] In some embodiments, in the above step S101, the loading process includes the following steps: S1012. Under stirring conditions, mixing and soaking the acidified sodium β-alumina and aniline, and then air-drying.

[0056] In some embodiments, in the above step S1012, the stirring speed is 3 rpm to 8 rpm.

[0057] In some embodiments, in the above step S1012, the time of the mixing and soaking is 20 min to 30 min.

[0058] In some embodiments, in the above step S1012, the time of the air-drying is 6 h to 12 h.

[0059] In some embodiments, in the above step S1012, the steps of mixing and soaking and then air-drying are repeated 2 to 4 times.

[0060] In some embodiments, in the above step S102, the pH value of the sodium β-alumina grafted aniline suspension is below 2.

[0061] In some embodiments, in the above step S102, the preparation of the sodium β-alumina grafted aniline suspension includes the following steps: S1021. Dispersing the sodium β-alumina grafted aniline in water and dropping dilute hydrochloric acid.

[0062] In the preparation of the above sodium β-alumina grafted aniline suspension, dropping dilute hydrochloric acid makes the suspension acidic, which is convenient for the subsequent reaction of aniline with sodium persulfate to generate high-conductivity viologen salt.

[0063] In some embodiments, in the above step S102, the preparation of the sodium persulfate solution includes the following steps: S1022. Mixing sodium persulfate and water to make a saturated sodium persulfate solution.

[0064] In some embodiments, in the above step S102, the mixing process includes the following steps: S1023. Under stirring conditions, mix the sodium β-aluminum oxide grafted aniline suspension and the sodium persulfate solution, and then wash and dry.

[0065] In some embodiments, in the above step S1023, the rotation speed of stirring is 3 rpm to 8 rpm.

[0066] In some embodiments, in the above step S1023, the temperature of the sodium β-aluminum oxide grafted aniline suspension is 0 °C to 5 °C.

[0067] In some embodiments, in the above step S1023, the temperature of the sodium persulfate solution is 0 °C to 5 °C.

[0068] In some embodiments, in the above step S1023, the step of mixing the sodium β-aluminum oxide grafted aniline suspension and the sodium persulfate solution includes: Drop the sodium persulfate solution into the sodium β-aluminum oxide grafted aniline suspension at a dropping rate of 30 d / min to 60 d / min.

[0069] In some embodiments, in the above step S1023, the washing step includes: Wash successively with 0.1 M HCl(aq), water, and ethanol.

[0070] In the above washing step, washing successively with 0.1 M HCl(aq), water, and ethanol can remove unreacted and ungrafted aniline monomers and sodium persulfate residues. It should be noted that the amounts of 0.1 M HCl(aq), water, and ethanol can be adjusted according to actual production needs and are not elaborated in the embodiments of the present invention. However, as an example, the volume is generally 2 to 3 times that of the product.

[0071] In some embodiments, in the above step S1023, the drying step includes: Vacuum dry the washed product at 50 °C to 60 °C.

[0072] In some embodiments, the time for vacuum drying is 12 h to 24 h.

[0073] In some embodiments, a method for preparing a sodium-ion solid-state battery is provided, and the steps are as follows: S11. Prepare a composite solid electrolyte according to the above method for preparing a composite solid electrolyte.

[0074] S21. Prepare a positive electrode plate.

[0075] S31. Assemble.

[0076] In some embodiments, in the above step S21, the steps of preparing the positive electrode sheet include: S211. Coating the positive electrode slurry on the positive electrode current collector, followed by drying, rolling, and slicing to obtain the positive electrode sheet; The positive electrode slurry includes a positive electrode active material, a conductive agent, and a binder.

[0077] In the above steps of preparing the positive electrode sheet, coating, drying, rolling, and slicing are all conventional techniques in the art, and specific conditions are not particularly limited in the embodiments of the present invention.

[0078] In some embodiments, in the above step S211, the mass ratio of the positive electrode active material, the conductive agent, and the binder is (80 - 90):(5 - 10):(5 - 10).

[0079] In some embodiments, in the above step S211, the conductive agent includes at least one of conductive carbon black, carbon nanotubes, and graphene@reduced graphene oxide.

[0080] In some embodiments, in the above step S211, the binder includes at least one of polyvinylidene fluoride (PVDF), polyacrylic acid (PAA), polytetrafluoroethylene (PTFE), sodium carboxymethyl cellulose (CMC), and sodium alginate (Na - alginate).

[0081] In some embodiments, in the above step S211, the preparation of the positive electrode slurry includes the following steps: After mixing the positive electrode active material, the conductive agent, and the binder, N - methylpyrrolidone (NMP) is added.

[0082] In the above preparation of the positive electrode slurry, N - methylpyrrolidone (NMP) is used to adjust the viscosity of the positive electrode slurry to meet the viscosity requirements for preparation. It should be noted that the addition amount of N - methylpyrrolidone is conventionally adjusted according to the specific viscosity of the required positive electrode slurry and is not particularly limited in the embodiments of the present invention.

[0083] In some embodiments, in the above step S211, the positive electrode current collector includes at least one of aluminum foil, stainless steel foil, and graphene film.

[0084] In some embodiments, in the above step S31, the steps of assembly include: Assembling the positive electrode sheet, the composite solid electrolyte, and the negative electrode sheet.

[0085] The following is further illustrated with specific examples. For the convenience of description, in the following examples and comparative examples: (1) The active material in the positive electrode sheet is Na2FePO4F / C, and the preparation method is as follows: ①Mix according to the mass ratio of Na2FePO4F / C: carbon nanotubes: polyvinylidene fluoride of 90:5:5, add the solvent N-methylpyrrolidone (NMP) to adjust the viscosity, and prepare the positive electrode slurry.

[0086] ②Uniformly coat the positive electrode slurry on one surface (perpendicular to the thickness direction) of the aluminum foil (positive electrode current collector) and dry it, then roll and slice to obtain the positive electrode sheet with the positive electrode film layer.

[0087] (2)The negative electrode sheet is a sodium sheet.

[0088] (3)The dilute acid solution used for acidified sodium β-alumina is dilute hydrochloric acid with a concentration of 0.8 mol / L.

[0089] Example 1 Example 1 provides a sodium-ion solid-state battery, which is composed of a positive electrode sheet, sodium β-alumina (Naβ-Al2O3) grafted with polyaniline, and a negative electrode sheet; Among them, the raw material sodium β-alumina has a porous structure, a porosity of 50%, and a pore diameter of 5 μm.

[0090] This example also provides a preparation method of a sodium-ion solid-state battery, and the steps are as follows: E10. Prepare a suspension of sodium β-alumina grafted with aniline E101. Mix sodium β-alumina and dilute hydrochloric acid, acidify at 65 °C for 7 h, then wash the sodium β-alumina with water until it is neutral, and then dry it at 90 °C to obtain acidified sodium β-alumina.

[0091] E102. Under the stirring condition of 7 rpm, mix and soak the acidified sodium β-alumina and aniline for 25 min, then air-dry for 8 h, and repeat the steps of soaking and air-drying 3 times to obtain sodium β-alumina grafted with aniline.

[0092] E103. Disperse the sodium β-alumina grafted with aniline in water, and dropwise add dilute hydrochloric acid to adjust the pH value to 0 to obtain a suspension of sodium β-alumina grafted with aniline.

[0093] E20. Prepare a sodium persulfate solution Mix sodium persulfate and water to make a saturated sodium persulfate solution.

[0094] E30. Prepare a composite solid electrolyte E301. Cool the suspension of sodium β-alumina grafted with aniline and the sodium persulfate solution to 0 °C respectively.

[0095] E302. Under the stirring condition of 3 rpm, drop the sodium persulfate solution into the suspension of sodium β-alumina grafted with aniline at a dropping rate of 40 d / min. After dropping, continue to stir for 2 h.

[0096] E303. Filter to obtain the solid product, and wash the solid product successively with 0.1 M HCl (aq), water, and ethanol.

[0097] E304. Vacuum-dry the washed product at 50 °C for 24 h to obtain the composite solid electrolyte.

[0098] E40. Assemble the positive electrode sheet, the composite solid electrolyte prepared in this example, and the negative electrode sheet to obtain a sodium-ion solid battery.

[0099] Example 2 Example 2 provides a sodium-ion solid battery, which consists of a positive electrode sheet, sodium β-aluminum oxide (Naβ-Al2O3) grafted with polyaniline, and a negative electrode sheet; Among them, the raw material sodium β-aluminum oxide has a porous structure, a porosity of 30%, and a pore diameter of 1 μm.

[0100] This example also provides a preparation method for a sodium-ion solid battery. The steps are basically the same as those in Example 1, except that: E102. Under the stirring condition of 5 rpm, mix and soak the acidified sodium β-aluminum oxide and aniline for 30 min, then air-dry for 12 h, and repeat the steps of soaking and air-drying 4 times to obtain sodium β-aluminum oxide grafted with aniline.

[0101] E301. Cool the sodium β-aluminum oxide grafted with aniline suspension and the sodium persulfate solution to 3 °C respectively.

[0102] E302. Under the stirring condition of 5 rpm, drop the sodium persulfate solution into the sodium β-aluminum oxide grafted with aniline suspension at a dropping rate of 30 d / min. After dropping, continue stirring for 2 h.

[0103] Example 3 Example 3 provides a sodium-ion solid battery, which consists of a positive electrode sheet, sodium β-aluminum oxide (Naβ-Al2O3) grafted with polyaniline, and a negative electrode sheet; Among them, the raw material sodium β-aluminum oxide has a porous structure, a porosity of 40%, and a pore diameter of 3 μm.

[0104] This example also provides a preparation method for a sodium-ion solid battery. The steps are basically the same as those in Example 1, except that: E102. Under the stirring condition of 8 rpm, mix and soak the acidified sodium β-aluminum oxide and aniline for 20 min, then air-dry for 6 h, and repeat the steps of soaking and air-drying 2 times to obtain sodium β-aluminum oxide grafted with aniline.

[0105] E301. Cool the sodium β-aluminum oxide grafted with aniline suspension and the sodium persulfate solution to 5 °C respectively.

[0106] E302. Under the stirring condition of 8 rpm, the sodium persulfate solution was dropped into the suspension of sodium β-aluminum oxide grafted with aniline at a dropping rate of 60 d / min. After the dropping was completed, stirring was continued for 2 h.

[0107] Example 4 Example 4 provides a sodium-ion solid-state battery, which is composed of a positive electrode plate, sodium β-aluminum oxide (Naβ-Al2O3) grafted with polyaniline, and a negative electrode plate; Among them, the raw material sodium β-aluminum oxide has a porous structure, a porosity of 35%, and a pore diameter of 2 μm.

[0108] This example also provides a preparation method of a sodium-ion solid-state battery. The steps are basically the same as those in Example 1, except that: E103. Disperse the sodium β-aluminum oxide grafted with aniline in water, and drop dilute hydrochloric acid to adjust the pH value to 1 to obtain a suspension of sodium β-aluminum oxide grafted with aniline.

[0109] E302. Under the stirring condition of 6 rpm, the sodium persulfate solution was dropped into the suspension of sodium β-aluminum oxide grafted with aniline at a dropping rate of 50 d / min. After the dropping was completed, stirring was continued for 3 h.

[0110] E304. Vacuum-dry the washed product at 50 °C for 24 h to obtain a composite solid electrolyte.

[0111] Example 5 Example 5 provides a sodium-ion solid-state battery, which is composed of a positive electrode plate, sodium β-aluminum oxide (Naβ-Al2O3) grafted with polyaniline, and a negative electrode plate; Among them, the raw material sodium β-aluminum oxide has a porous structure, a porosity of 45%, and a pore diameter of 4 μm.

[0112] This example also provides a preparation method of a sodium-ion solid-state battery. The steps are basically the same as those in Example 1, except that: E103. Disperse the sodium β-aluminum oxide grafted with aniline in water, and drop dilute hydrochloric acid to adjust the pH value to 2 to obtain a suspension of sodium β-aluminum oxide grafted with aniline.

[0113] E302. Under the stirring condition of 4 rpm, the sodium persulfate solution was dropped into the suspension of sodium β-aluminum oxide grafted with aniline at a dropping rate of 35 d / min. After the dropping was completed, stirring was continued for 2 h.

[0114] E304. Vacuum-dry the washed product at 60 °C for 12 h to obtain a composite solid electrolyte.

[0115] Example 6 Example 6 provides a sodium-ion solid-state battery, which is composed of a positive electrode sheet, sodium β-aluminum oxide (Naβ-Al2O3) grafted with polyaniline, and a negative electrode sheet; Among them, the raw material sodium β-aluminum oxide has a porous structure, a porosity of 50%, and a pore diameter of 4 μm.

[0116] This example also provides a preparation method of a sodium-ion solid-state battery. The steps are basically the same as those in Example 1, except that: E103. Disperse sodium β-aluminum oxide grafted with aniline in water, and add dilute hydrochloric acid dropwise to adjust the pH value to 2 to obtain a sodium β-aluminum oxide grafted with aniline suspension.

[0117] E301. Cool the sodium β-aluminum oxide grafted with aniline suspension and the sodium persulfate solution to 2 °C respectively.

[0118] E302. Under the stirring condition of 8 rpm, drop the sodium persulfate solution into the sodium β-aluminum oxide grafted with aniline suspension at a dropping rate of 55 d / min. After dropping, continue to stir for 2 h.

[0119] E304. Vacuum-dry the washed product at 55 °C for 20 h to obtain a composite solid electrolyte.

[0120] Example 7 Example 7 provides a sodium-ion solid-state battery, which is composed of a positive electrode sheet, sodium β-aluminum oxide (Naβ-Al2O3) grafted with polyaniline, and a negative electrode sheet; Among them, the raw material sodium β-aluminum oxide has a porous structure, a porosity of 45%, and a pore diameter of 5 μm.

[0121] This example also provides a preparation method of a sodium-ion solid-state battery. The steps are basically the same as those in Example 1, except that: E103. Disperse sodium β-aluminum oxide grafted with aniline in water, and add dilute hydrochloric acid dropwise to adjust the pH value to 1 to obtain a sodium β-aluminum oxide grafted with aniline suspension.

[0122] E301. Cool the sodium β-aluminum oxide grafted with aniline suspension and the sodium persulfate solution to 4 °C respectively.

[0123] E302. Under the stirring condition of 5 rpm, drop the sodium persulfate solution into the sodium β-aluminum oxide grafted with aniline suspension at a dropping rate of 45 d / min. After dropping, continue to stir for 2 h.

[0124] E304. Vacuum-dry the washed product at 60 °C for 18 h to obtain a composite solid electrolyte.

[0125] Comparative Example 1 Comparative Example 1 provides a preparation method of a sodium-ion solid-state battery. The steps are as follows: D10. Mix sodium β-aluminum oxide and aniline under stirring at 7 rpm, soak the mixture for 25 min and then air-dry for 8 h. Repeat the steps of soaking and air-drying three times to obtain an intermediate product.

[0126] D20. Disperse the intermediate product in water, and adjust the pH value to 0 by dropping dilute hydrochloric acid to obtain a suspension of the intermediate product.

[0127] D30. Prepare a sodium persulfate solution Mix sodium persulfate and water to make a saturated sodium persulfate solution.

[0128] D40. Prepare a composite solid electrolyte D401. Cool the suspension of the intermediate product and the sodium persulfate solution to 0 °C respectively.

[0129] D402. Under stirring at 3 rpm, drop the sodium persulfate solution into the suspension of the intermediate product at a dropping rate of 40 d / min. After dropping, continue stirring for 2 h.

[0130] D403. Filter to obtain the solid product, and wash the solid product with 0.1 M HCl (aq), water and ethanol in sequence.

[0131] D404. Vacuum-dry the washed product at 50 °C for 24 h to obtain the composite solid electrolyte.

[0132] D50. Assemble the positive electrode plate, the composite solid electrolyte prepared in this comparative example and the negative electrode plate to obtain a sodium-ion solid-state battery.

[0133] Comparative Example 2 Comparative Example 2 provides a method for preparing a sodium-ion solid-state battery. The steps are basically the same as those in Example 1, except that: E301. The temperatures of the suspension of sodium β-aluminum oxide grafted with aniline and the sodium persulfate solution are 10 °C respectively.

[0134] Comparative Example 3 Comparative Example 3 provides a method for preparing a sodium-ion solid-state battery. The steps are basically the same as those in Example 1, except that: E103. Disperse sodium β-aluminum oxide grafted with aniline in water to obtain a suspension of sodium β-aluminum oxide grafted with aniline.

[0135] Comparative Example 4 Comparative Example 4 provides a method for preparing a sodium-ion solid-state battery. The steps are basically the same as those in Example 1, except that: E302. Under stirring at 3 rpm, add the sodium persulfate solution to the suspension of sodium β-aluminum oxide grafted with aniline at one time, and then continue stirring for 2 h.

[0136] Comparative Example 5 Comparative Example 5 provides a method for preparing a sodium-ion solid-state battery. The steps are basically the same as those in Example 1, except that: E304. The washed product was vacuum dried at 100 °C for 18 h to obtain a composite solid electrolyte.

[0137] To verify the progressiveness of the sodium-ion solid-state battery and its preparation method provided in the embodiments of the present invention, in the preparation methods provided in the embodiments and comparative examples, the four-probe method was used to detect the conductivity of the prepared composite solid electrolyte; the capacity retention rate (%) of the prepared sodium-ion solid-state battery at 25 °C and 3C cycling for 500 times was detected. The results are shown in Table 1 below.

[0138]

[0139] At least the following conclusions can be obtained from the above table: (1) In Comparative Example 1, sodium β-alumina was not acidified, and the prepared composite solid electrolyte, although the conductivity was not much different from that in Example 1, its capacity retention rate decreased significantly. This shows that in the composite solid electrolyte prepared in Comparative Example 1, polyaniline and sodium β-alumina are only physically adsorbed, and polyaniline is not grafted onto the surface of sodium β-alumina, resulting in poor interfacial stability between the solid electrolyte and the electrode material in the sodium-ion solid-state battery, and the capacity of the battery decays rapidly. Thus, it can be seen that the composite solid electrolyte provided in the embodiments of the present invention, which contains polyaniline grafted on sodium β-alumina (Naβ-Al2O3), can significantly improve the interfacial stability between the composite solid electrolyte and the electrode material, and the capacity of the battery decays slowly.

[0140] (2) In Comparative Example 2, when preparing the composite solid electrolyte, the temperature of the sodium β-alumina grafted aniline suspension and the sodium persulfate solution was 10 °C, and the conductivity of the prepared composite solid electrolyte decreased significantly compared with that in the example. This shows that when preparing the composite solid electrolyte, too many side products that do not have conductive properties are generated by the side reaction of aniline and sodium persulfate, which not only reduces the conductivity of the solid electrolyte, but also affects the interfacial stability between the solid electrolyte and the electrode material, further leading to a rapid decay of the battery capacity. Thus, it can be seen that in the preparation method of the sodium-ion solid-state battery provided in the embodiments of the present invention, when preparing the composite solid electrolyte, under the preparation conditions provided in the embodiments of the present invention, a perylene diimide salt with high conductivity can be prepared and grafted onto sodium β-alumina in a chemical bonding manner, so that the composite solid electrolyte has a very high conductivity, and further, in the sodium-ion solid-state battery, there is a very high interfacial stability between the composite solid electrolyte and the electrode material, and the capacity of the battery decays slowly.

[0141] It should be noted that the present invention is not limited to the above-described embodiments. The above-described embodiments are merely examples, and embodiments having the same constitution and exhibiting the same effects as the technical idea within the scope of the technical solution of the present invention are all included in the technical scope of the present invention. In addition, within the scope not departing from the gist of the present invention, various modifications that can be conceived by those skilled in the art to the embodiments, and other modes constructed by combining some constituent elements in the embodiments are also included in the scope of the present invention.

Claims

1. A sodium-ion solid-state battery, characterized in that, It includes a composite solid electrolyte; The composite solid electrolyte includes sodium β-alumina grafted with polyaniline; The raw materials of the sodium β-alumina grafted with polyaniline include sodium β-alumina, aniline, and ammonium persulfate; The mass ratio of the sodium β-alumina, the aniline, and the ammonium persulfate is 1:3 - 6:

1.

2. The sodium-ion solid-state battery according to claim 1, characterized in that, The sodium β-alumina has a porous structure.

3. The sodium-ion solid-state battery according to claim 2, wherein It satisfies at least one of the following conditions (1) - (2): (1) The porosity of the sodium β-alumina is 30% - 50%; (2) The pore diameter of the sodium β-alumina is 1 μm - 5 μm.

4. A method for preparing a sodium-ion solid-state battery according to any one of claims 1 to 3, characterized in that, It includes the following steps: Prepare a composite solid electrolyte.

5. The preparation method of the sodium-ion solid-state battery according to claim 4, wherein, The preparation of the composite solid electrolyte includes the following steps: Perform a loading treatment on acidified sodium β-alumina and aniline to obtain sodium β-alumina grafted with aniline; Mix the sodium β-alumina grafted with aniline suspension with an ammonium persulfate solution to obtain sodium β-alumina grafted with polyaniline.

6. The preparation method of the sodium-ion solid-state battery according to claim 5, characterized in that, It satisfies at least one of the following conditions (1) - (3): (1) The loading treatment includes the following steps: Under stirring conditions, mix and soak the acidified sodium β-alumina and aniline and then air-dry; (2) The pH value of the sodium β-alumina grafted with aniline suspension is below 2; (3) The mixing treatment includes the following steps: Under stirring conditions, mix the sodium β-alumina grafted with aniline suspension and the ammonium persulfate solution, then wash and dry.

7. The preparation method of the sodium-ion solid-state battery according to claim 6, characterized in that, It satisfies at least one of the following conditions (1) - (3): (1) The mixing and soaking time is 20 min - 30 min; (2) The air-drying time is 6 h - 12 h; (3) The steps of mixing, soaking, and then air-drying are repeated 2 - 4 times.

8. The method for preparing a sodium-ion solid-state battery according to claim 6 or 7, characterized in that, It satisfies at least one of the following conditions (1) - (2): (1) The temperature of the sodium β-alumina grafted with aniline suspension is 0°C - 5°C; (2) The temperature of the ammonium persulfate solution is 0°C - 5°C.

9. The preparation method of the sodium-ion solid-state battery according to claim 8, wherein It satisfies at least one of the following conditions (1) - (2): (1) The step of mixing the sodium β-alumina grafted with aniline suspension and the ammonium persulfate solution includes: Drop the ammonium persulfate solution into the sodium β-alumina grafted with aniline suspension at a dropping rate of 30 d / min - 60 d / min; (2) The drying step includes: Vacuum-dry the washed product at 50°C - 60°C.

10. Application of a sodium-ion solid-state battery as described in any one of claims 1 - 5 in the new energy field.

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