A sodium ion solid-state battery and its preparation method and application

Abstract

The present invention relates to the technical field of sodium-ion solid-state batteries, and more specifically to a sodium-ion solid-state battery, its preparation method, and its application. The sodium-ion solid-state battery comprises a composite solid-state electrolyte comprising sodium β-alumina (Naβ-Al2O3) grafted with polyaniline. The polyaniline forms a chemically bonded graft structure within the pores of the sodium β-alumina, resulting in high electrical conductivity and interfacial stability with electrode materials, thereby enabling the sodium-ion solid-state battery to possess high charge / discharge capacity and rate performance.

Description

Technical Field

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

[0002] Sodium-ion solid-state batteries (SSBs) are a new type of battery that uses solid electrolytes instead of traditional liquid electrolytes to achieve efficient sodium ion transfer between the positive and negative electrodes, thereby replacing the flammable organic electrolytes and separators in traditional liquid SSBs. SSBs are widely used due to their excellent chemical and thermal stability. However, the ionic conductivity of the solid electrolytes in current SSBs is generally lower than that of liquid electrolytes, which limits the battery's rate performance and practical applications. Furthermore, the poor interfacial stability between the solid electrolyte and the electrode material leads to rapid capacity decay. Summary of the Invention

[0003] To solve the above problems, the present invention provides a sodium ion solid-state battery and its preparation method and application, so as to solve at least one aspect of the above technical problems.

[0004] The present invention is achieved through the following technical solutions:

[0005] In a first aspect, the present invention provides a sodium ion solid-state battery, comprising a composite solid-state electrolyte;

[0006] The composite solid electrolyte includes sodium beta-alumina (Nabeta-Al2O3) grafted polyaniline.

[0007] In some possible implementations, the raw materials for the sodium β-alumina grafted polyaniline include sodium β-alumina, aniline, and ammonium persulfate.

[0008] In some possible implementations, the mass ratio of the sodium β-alumina, the aniline, and the ammonium persulfate is 1:(3-6):1.

[0009] In some possible implementations, the sodium β-alumina has a porous structure.

[0010] In some possible implementations, the porosity of the sodium β-alumina is 30% to 50%.

[0011] In some possible implementations, the pore size of the sodium β-alumina is 1 μm to 5 μm.

[0012] In a second aspect, the present invention provides a method for preparing the above-mentioned sodium ion solid-state battery, comprising the following steps:

[0013] Preparation of composite solid electrolytes.

[0014] In some possible implementations, the preparation of the composite solid electrolyte includes the following steps:

[0015] The acidified sodium β-alumina and aniline are subjected to loading treatment to obtain sodium β-alumina grafted aniline;

[0016] The sodium beta-alumina grafted aniline suspension is mixed with a sodium persulfate solution to obtain the sodium beta-alumina grafted polyaniline.

[0017] In some possible implementations, the load processing includes the following steps:

[0018] Under stirring conditions, the acidified sodium β-alumina and aniline are mixed, soaked, and then air-dried.

[0019] In some possible implementations, the pH value of the sodium β-alumina grafted aniline suspension is 2 or less.

[0020] In some possible implementations, the mixing process includes the following steps:

[0021] Under stirring conditions, the sodium β-alumina grafted aniline suspension and the sodium persulfate solution are mixed, washed and dried.

[0022] In some possible implementations, the mixing and soaking time is 20 min to 30 min.

[0023] In some possible implementations, the air-drying time is 6 hours to 12 hours.

[0024] In some possible implementations, the steps of mixing, soaking, and then air-drying are repeated 2 to 4 times.

[0025] In some possible implementations, the temperature of the sodium β-alumina grafted aniline suspension is 0°C to 5°C.

[0026] In some possible implementations, the temperature of the sodium persulfate solution is 0°C to 5°C.

[0027] In some possible implementations, the step of mixing the sodium β-alumina grafted aniline suspension and the sodium persulfate solution comprises:

[0028] The sodium persulfate solution is dripped into the sodium β-alumina grafted aniline suspension at a dripping rate of 30d / min~60d / min.

[0029] In some possible implementations, the drying step includes:

[0030] The washed product was vacuum dried at 50°C~60°C.

[0031] In a third aspect, the present invention provides an application of the above-mentioned sodium ion solid-state battery in the field of new energy.

[0032] The sodium ion solid-state battery and its preparation method provided by the present invention have at least the following beneficial technical effects compared with the prior art:

[0033] In the sodium ion solid-state battery provided by the present invention, the composite solid-state electrolyte has a chemically bonded graft structure between polyaniline and the surface of sodium β-alumina, so that the composite solid-state electrolyte has high electrical conductivity, and the contact between the surface polyaniline and the electrode material is excellent, thereby achieving high interface stability, thereby enabling the sodium ion solid-state battery to have high charge and discharge capacity and rate performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present drawings or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present drawings. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0035] Figure 1 A schematic diagram of a composite solid electrolyte graft structure provided by an embodiment of the present invention;

[0036] Figure 2 A schematic structural diagram of a sodium ion solid-state battery provided in an embodiment of the present invention;

[0037] Figure 3 This is the cycling curve of the sodium ion solid-state battery provided in Example 1 of the present invention at 25°C.

[0038] Explanation of the accompanying symbols: 1-sodium β-alumina pores, 2-polyaniline, 3-positive electrode sheet, 4-composite solid electrolyte, 5-negative electrode sheet.

[0039] The purpose, features and advantages of this drawing will be further described with reference to the accompanying drawings in conjunction with the embodiments. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is described and illustrated below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended 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 work are within the scope of protection of the present invention.

[0041] For ordinary technicians in the field related to the contents disclosed in the present invention, some changes in design, manufacturing or production based on the technical contents disclosed in the present invention are just conventional technical means and should not be understood as the contents disclosed in the present invention are insufficient.

[0042] Unless otherwise specified, all embodiments and optional embodiments of the present invention can be combined with each other to form a new technical solution, and all technical features and optional technical features of the present invention can be combined with each other to form a new technical solution.

[0043] A first aspect of an embodiment of the present invention provides a sodium ion solid-state battery, such as Figure 1 As shown, comprising a composite solid electrolyte;

[0044] The composite solid electrolyte includes sodium β-alumina (Naβ-Al2O3) grafted polyaniline.

[0045] In the sodium ion solid-state battery provided by an embodiment of the present invention, sodium β-alumina (Naβ-Al2O3) grafted polyaniline has very high ionic conductivity, thereby improving the interface stability, charge and discharge capacity and rate performance of the sodium ion solid-state battery.

[0046] In some embodiments, raw materials for sodium β-alumina (Naβ-Al2O3) grafted polyaniline include sodium β-alumina, aniline, and ammonium persulfate.

[0047] In some embodiments, the mass ratio of sodium β-alumina, aniline, and ammonium persulfate is 1:(3-6):1. In this case, the aniline is in excess relative to the ammonium persulfate, resulting in incomplete polymerization of the aniline, resulting in the formation of emeraldine salt having high electrical conductivity.

[0048] In some embodiments, the sodium β-alumina has a porous structure, and in this case, the polyaniline forms a chemically bonded graft structure in the pores of the sodium β-alumina.

[0049] In some embodiments, the porosity of sodium β-alumina is 30% to 50%.

[0050] In some embodiments, the pore size of sodium β-alumina is 1 μm to 5 μm.

[0051] In some embodiments, aniline has a CAS number of 62-53-3.

[0052] In some embodiments, a sodium ion solid-state battery is provided, such as Figure 2 As shown, it includes a positive electrode plate 3, the above-mentioned composite solid electrolyte 4 and a negative electrode plate 5.

[0053] In some embodiments, the positive electrode active material in the positive electrode sheet includes NaNiO2, NaMnO2, NaNi 1 / 3 Fe 1 / 3 Mn 1 / At least one of 3O2, NaFePO4, Na3V2(PO4)3@C, Na2Fe2(SO4)3@C@GO, and Na2FePO4F / C.

[0054] In some embodiments, the material of the negative electrode plate includes sodium plate.

[0055] A second aspect of an embodiment of the present invention provides a method for preparing the above-mentioned sodium ion solid-state battery, comprising the following steps:

[0056] S10. Preparation of composite solid electrolyte.

[0057] In the method for preparing a sodium-ion solid-state battery provided by an embodiment of the present invention, polyaniline is grafted onto the surface of sodium β-alumina (Naβ-Al2O3) during the preparation of the composite solid-state electrolyte. This increases the specific surface area of the electrolyte and, in turn, improves the ionic conductivity of the solid-state electrolyte. Furthermore, the polyaniline grafted onto the sodium β-alumina creates a closer contact with the electrode material, thereby reducing interfacial reactions between the solid-state electrolyte and the electrode material, thereby improving the interfacial stability of the sodium-ion solid-state battery.

[0058] In some embodiments, in the above step S10, preparing the composite solid electrolyte includes the following steps:

[0059] S101. Carry out loading treatment on the acidified sodium β-alumina and aniline to obtain sodium β-alumina grafted aniline.

[0060] S102. The sodium β-alumina grafted aniline suspension is mixed with a sodium persulfate solution to obtain sodium β-alumina grafted polyaniline.

[0061] In the above steps of preparing the composite solid electrolyte, sodium β-alumina is acidified to graft aniline onto the surface of the sodium β-alumina, and then oxidatively polymerized with ammonium sulfate to obtain sodium β-alumina (Naβ-Al2O3) grafted polyaniline.

[0062] In some embodiments, in step S101 above, the step of preparing the acidified sodium β-alumina comprises:

[0063] S1011. Sodium β-alumina and dilute acid solution are mixed and acidified, then washed and dried.

[0064] In the above-mentioned step of acidifying sodium β-alumina, sodium β-alumina and dilute acid solution are mixed and acidified, and then washed to remove free acid on the surface of sodium β-alumina, and dried to remove the washing solvent on the surface.

[0065] In some embodiments, in 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 β-alumina.

[0066] In some embodiments, in the above step S1011, the concentration of the dilute acid solution is 0.1 mol / L to 1 mol / L.

[0067] In some embodiments, in the above step S1011, the temperature of the mixed acidification is 60°C to 70°C.

[0068] In some embodiments, in the above step S1011, the mixing and acidification time is 6 hours to 8 hours.

[0069] In some embodiments, in the above step S1011, the washing step includes:

[0070] Wash the sodium β-alumina with water until it is neutral.

[0071] In some embodiments, in step S1011 , the drying temperature is 90° C. to 100° C. In this case, this temperature removes the moisture remaining on the surface of the sodium β-alumina after washing.

[0072] In some embodiments, in the above step S101, the load processing includes the following steps:

[0073] S1012. Under stirring conditions, mix the acidified sodium β-alumina and aniline, soak them, and then air-dry them.

[0074] In some embodiments, in the above step S1012, the stirring speed is 3 rpm to 8 rpm.

[0075] In some embodiments, in the above step S1012, the mixing and soaking time is 20 minutes to 30 minutes.

[0076] In some embodiments, in the above step S1012, the air-drying time is 6 hours to 12 hours.

[0077] In some embodiments, in the above step S1012, the steps of mixing, soaking, and air-drying are repeated 2 to 4 times.

[0078] In some embodiments, in the above step S102 , the pH value of the sodium β-alumina grafted aniline suspension is below 2.

[0079] In some embodiments, in the above step S102, the preparation of the sodium β-alumina grafted aniline suspension comprises the following steps:

[0080] S1021. Sodium β-alumina grafted aniline is dispersed in water and dilute hydrochloric acid is added dropwise.

[0081] In the preparation of the sodium β-alumina grafted aniline suspension, dilute hydrochloric acid is added dropwise to make the suspension acidic, so as to facilitate the subsequent reaction of aniline with sodium persulfate to form emeraldine salt with high conductivity.

[0082] In some embodiments, in step S102 above, the preparation of the sodium persulfate solution comprises the following steps:

[0083] S1022. Sodium persulfate and water are mixed to prepare a saturated sodium persulfate solution.

[0084] In some embodiments, in the above step S102, the mixing process includes the following steps:

[0085] S1023. Under stirring conditions, mix the sodium β-alumina grafted aniline suspension and the sodium persulfate solution, then wash and dry.

[0086] In some embodiments, in the above step S1023, the stirring speed is 3 rpm to 8 rpm.

[0087] In some embodiments, in step S1023 , the temperature of the sodium β-alumina grafted aniline suspension is 0° C. to 5° C.

[0088] In some embodiments, in step S1023, the temperature of the sodium persulfate solution is 0°C to 5°C.

[0089] In some embodiments, in step S1023, the step of mixing the sodium β-alumina grafted aniline suspension and the sodium persulfate solution comprises:

[0090] The sodium persulfate solution is dripped into the sodium β-alumina grafted aniline suspension at a dripping rate of 30d / min~60d / min.

[0091] In some embodiments, in step S1023, the washing step includes:

[0092] The product was washed with 0.1 M HCl (aq), water and ethanol in that order.

[0093] In the aforementioned washing steps, 0.1M HCl (aq), water, and ethanol are sequentially used to remove unreacted and ungrafted aniline monomer and residual sodium persulfate. It should be noted that the amounts of 0.1M HCl (aq), water, and ethanol used can be adjusted based on actual production needs and are not detailed in the Examples. However, as an example, the volume is generally 2 to 3 times that of the product.

[0094] In some embodiments, in the above step S1023, the drying step includes:

[0095] The washed product was vacuum dried at 50°C~60°C.

[0096] In some embodiments, the vacuum drying time is 12 hours to 24 hours.

[0097] In some embodiments, a method for preparing a sodium ion solid-state battery is provided, comprising the following steps:

[0098] S11. Prepare a composite solid electrolyte according to the above-mentioned composite solid electrolyte preparation method.

[0099] S21. Prepare the positive electrode sheet.

[0100] S31. Assembly.

[0101] In some embodiments, in the above step S21, the step of preparing the positive electrode sheet includes:

[0102] S211. The positive electrode slurry is coated on the positive electrode current collector and then dried, rolled and sliced to obtain a positive electrode sheet;

[0103] The positive electrode slurry includes a positive electrode active material, a conductive agent and a binder.

[0104] In the above steps of preparing the positive electrode sheet, coating, drying, rolling and slicing are all conventional techniques in the art, and the specific conditions are not particularly limited in the embodiments of the present invention.

[0105] 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).

[0106] 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.

[0107] 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).

[0108] In some embodiments, in the above step S211, the preparation of the positive electrode slurry includes the following steps:

[0109] After the positive electrode active material, conductive agent and binder are mixed, N-methylpyrrolidone (NMP) is added.

[0110] In the preparation of the positive electrode slurry, N-methylpyrrolidone (NMP) is used to adjust the viscosity of the positive electrode slurry so that the positive electrode slurry meets the viscosity requirements of the preparation. It should be noted that the amount of N-methylpyrrolidone added is conventionally adjusted according to the specific viscosity of the desired positive electrode slurry and is not particularly limited in the embodiments of the present invention.

[0111] 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.

[0112] In some embodiments, in the above step S31, the assembling step includes:

[0113] Assemble the positive electrode sheet, composite solid electrolyte and negative electrode sheet.

[0114] The following is further described in conjunction with specific examples. For the convenience of explanation, the following examples and comparative examples involve:

[0115] (1) The active material in the positive electrode is Na2FePO4F / C, and the preparation method is as follows:

[0116] ① Na2FePO4F / C: carbon nanotubes: polyvinylidene fluoride were mixed in a mass ratio of 90:5:5, and solvent N-methylpyrrolidone (NMP) was added to adjust the viscosity to prepare a positive electrode slurry.

[0117] ② The positive electrode slurry is evenly coated on one surface (perpendicular to the thickness direction) of the aluminum foil (positive electrode current collector) and dried, and then rolled and sliced to obtain a positive electrode sheet containing a positive electrode film layer.

[0118] (2) The negative electrode is a sodium plate.

[0119] (3) The dilute acid solution used to acidify sodium β-alumina is dilute hydrochloric acid with a concentration of 0.8 mol / L.

[0120] Example 1

[0121] Example 1 provides a sodium ion solid-state battery, comprising a positive electrode sheet, sodium β-alumina (Naβ-Al2O3) grafted polyaniline, and a negative electrode sheet;

[0122] Among them, the raw material sodium β-alumina has a porous structure with a porosity of 50% and a pore size of 5μm.

[0123] This embodiment also provides a method for preparing a sodium ion solid-state battery, which comprises the following steps:

[0124] E10. Preparation of sodium β-alumina grafted aniline suspension

[0125] E101. Sodium β-alumina and dilute hydrochloric acid are mixed and acidified at 65°C for 7 hours, the sodium β-alumina is washed with water until neutral, and then dried at 90°C to obtain acidified sodium β-alumina.

[0126] E102. Under stirring at 7 rpm, the acidified sodium β-alumina and aniline were mixed and soaked for 25 minutes, followed by air-drying for 8 hours. The soaking and air-drying steps were repeated three times to obtain sodium β-alumina grafted aniline.

[0127] E103. Disperse sodium β-alumina grafted aniline in water, add dilute hydrochloric acid dropwise to adjust the pH value to 0, and obtain a sodium β-alumina grafted aniline suspension.

[0128] E20. Preparation of sodium persulfate solution

[0129] Sodium persulfate and water are mixed to prepare a saturated sodium persulfate solution.

[0130] E30. Preparation of composite solid electrolytes

[0131] E301. Cool the sodium β-alumina grafted aniline suspension and sodium persulfate solution to 0℃ respectively.

[0132] E302. Under stirring conditions of 3 rpm, add the sodium persulfate solution to the sodium β-alumina grafted aniline suspension at a dropping rate of 40 d / min. After the addition is complete, continue stirring for 2 h.

[0133] E303. Filter the solid product and wash it with 0.1M HCl (aq), water and ethanol in sequence.

[0134] E304. The washed product was vacuum dried at 50°C for 24 h to obtain a composite solid electrolyte.

[0135] E40. Assemble the positive electrode sheet, the composite solid electrolyte prepared in this embodiment, and the negative electrode sheet to obtain a sodium ion solid-state battery.

[0136] Example 2

[0137] Example 2 provides a sodium ion solid-state battery, comprising a positive electrode sheet, sodium β-alumina (Naβ-Al2O3) grafted polyaniline, and a negative electrode sheet;

[0138] Among them, the raw material sodium β-alumina has a porous structure with a porosity of 30% and a pore size of 1 μm.

[0139] This embodiment also provides a method for preparing a sodium ion solid-state battery. The steps are basically the same as those in Example 1, except that:

[0140] E102. Under stirring at 5 rpm, the acidified sodium β-alumina and aniline were mixed and soaked for 30 minutes, followed by air-drying for 12 hours. The soaking and air-drying steps were repeated four times to obtain sodium β-alumina grafted aniline.

[0141] E301. Cool the sodium β-alumina grafted aniline suspension and sodium persulfate solution to 3°C respectively.

[0142] E302. Under stirring conditions of 5 rpm, add the sodium persulfate solution to the sodium β-alumina grafted aniline suspension at a dropping rate of 30 d / min. After the addition is completed, continue stirring for 2 h.

[0143] Example 3

[0144] Example 3 provides a sodium ion solid-state battery, comprising a positive electrode sheet, sodium β-alumina (Naβ-Al2O3) grafted polyaniline, and a negative electrode sheet;

[0145] Among them, the raw material sodium β-alumina has a porous structure with a porosity of 40% and a pore size of 3μm.

[0146] This embodiment also provides a method for preparing a sodium ion solid-state battery. The steps are basically the same as those in Example 1, except that:

[0147] E102. Under stirring at 8 rpm, the acidified sodium β-alumina and aniline were mixed and soaked for 20 minutes, followed by air-drying for 6 hours. The soaking and air-drying steps were repeated twice to obtain sodium β-alumina grafted aniline.

[0148] E301. Cool the sodium β-alumina grafted aniline suspension and sodium persulfate solution to 5°C respectively.

[0149] E302. Under stirring conditions of 8 rpm, add the sodium persulfate solution to the sodium β-alumina grafted aniline suspension at a dropping rate of 60 d / min. After the addition is completed, continue stirring for 2 h.

[0150] Example 4

[0151] Example 4 provides a sodium ion solid-state battery, comprising a positive electrode sheet, sodium β-alumina (Naβ-Al2O3) grafted polyaniline, and a negative electrode sheet;

[0152] Among them, the raw material sodium β-alumina has a porous structure with a porosity of 35% and a pore size of 2μm.

[0153] This embodiment also provides a method for preparing a sodium ion solid-state battery. The steps are basically the same as those in Example 1, except that:

[0154] E103. Disperse sodium β-alumina grafted aniline in water, add dilute hydrochloric acid dropwise to adjust the pH value to 1, and obtain a sodium β-alumina grafted aniline suspension.

[0155] E302. Under stirring conditions of 6 rpm, add the sodium persulfate solution to the sodium β-alumina grafted aniline suspension at a dropping rate of 50 d / min. After the addition is completed, continue stirring for 3 h.

[0156] E304. The washed product was vacuum dried at 50°C for 24 h to obtain a composite solid electrolyte.

[0157] Example 5

[0158] Example 5 provides a sodium ion solid-state battery, comprising a positive electrode sheet, sodium β-alumina (Naβ-Al2O3) grafted polyaniline, and a negative electrode sheet;

[0159] Among them, the raw material sodium β-alumina has a porous structure with a porosity of 45% and a pore size of 4μm.

[0160] This embodiment also provides a method for preparing a sodium ion solid-state battery. The steps are basically the same as those in Example 1, except that:

[0161] E103. Disperse sodium β-alumina grafted aniline in water, add dilute hydrochloric acid dropwise to adjust the pH value to 2, and obtain a sodium β-alumina grafted aniline suspension.

[0162] E302. Under stirring conditions of 4 rpm, add the sodium persulfate solution to the sodium β-alumina grafted aniline suspension at a rate of 35 d / min. After the addition is complete, continue stirring for 2 h.

[0163] E304. The washed product was vacuum dried at 60°C for 12 h to obtain a composite solid electrolyte.

[0164] Example 6

[0165] Example 6 provides a sodium ion solid-state battery, comprising a positive electrode sheet, sodium β-alumina (Naβ-Al2O3) grafted polyaniline, and a negative electrode sheet;

[0166] Among them, the raw material sodium β-alumina has a porous structure with a porosity of 50% and a pore size of 4μm.

[0167] This embodiment also provides a method for preparing a sodium ion solid-state battery. The steps are basically the same as those in Example 1, except that:

[0168] E103. Disperse sodium β-alumina grafted aniline in water, add dilute hydrochloric acid dropwise to adjust the pH value to 2, and obtain a sodium β-alumina grafted aniline suspension.

[0169] E301. Cool the sodium β-alumina grafted aniline suspension and sodium persulfate solution to 2°C respectively.

[0170] E302. Under stirring conditions of 8 rpm, add the sodium persulfate solution to the sodium β-alumina grafted aniline suspension at a dropping rate of 55 d / min. After the addition is completed, continue stirring for 2 h.

[0171] E304. The washed product was vacuum dried at 55°C for 20 h to obtain a composite solid electrolyte.

[0172] Example 7

[0173] Example 7 provides a sodium ion solid-state battery, comprising a positive electrode sheet, sodium β-alumina (Naβ-Al2O3) grafted polyaniline, and a negative electrode sheet;

[0174] Among them, the raw material sodium β-alumina has a porous structure with a porosity of 45% and a pore size of 5μm.

[0175] This embodiment also provides a method for preparing a sodium ion solid-state battery. The steps are basically the same as those in Example 1, except that:

[0176] E103. Disperse sodium β-alumina grafted aniline in water, add dilute hydrochloric acid dropwise to adjust the pH value to 1, and obtain a sodium β-alumina grafted aniline suspension.

[0177] E301. Cool the sodium β-alumina grafted aniline suspension and sodium persulfate solution to 4°C respectively.

[0178] E302. Under stirring conditions of 5 rpm, add the sodium persulfate solution to the sodium β-alumina grafted aniline suspension at a dropping rate of 45 d / min. After the addition is completed, continue stirring for 2 h.

[0179] E304. The washed product was vacuum dried at 60°C for 18 h to obtain a composite solid electrolyte.

[0180] Comparative Example 1

[0181] Comparative Example 1 provides a method for preparing a sodium ion solid-state battery, the steps of which are as follows:

[0182] D10. Under stirring at 7 rpm, soak the mixture of sodium β-alumina and aniline for 25 minutes and then air-dry for 8 hours. Repeat the soaking and air-drying steps three times to obtain an intermediate product.

[0183] D20. Disperse the intermediate product in water and add dilute hydrochloric acid dropwise to adjust the pH to 0 to obtain an intermediate product suspension.

[0184] D30. Preparation of sodium persulfate solution

[0185] Sodium persulfate and water are mixed to prepare a saturated sodium persulfate solution.

[0186] D40. Preparation of composite solid electrolytes

[0187] D401. Cool the intermediate product suspension and sodium persulfate solution to 0°C respectively.

[0188] D402. Under stirring at 3 rpm, add the sodium persulfate solution to the intermediate product suspension at a rate of 40 d / min. After the addition is complete, continue stirring for 2 h.

[0189] D403. Filter the solid product and wash it with 0.1M HCl (aq), water and ethanol in sequence.

[0190] D404. The washed product was vacuum dried at 50°C for 24 h to obtain a composite solid electrolyte.

[0191] D50. Assemble the positive electrode sheet, the composite solid electrolyte prepared in this comparative example, and the negative electrode sheet to obtain a sodium ion solid-state battery.

[0192] Comparative Example 2

[0193] 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:

[0194] E301. Set the temperature of sodium β-alumina grafted aniline suspension and sodium persulfate solution to 10℃ respectively.

[0195] Comparative Example 3

[0196] 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:

[0197] E103. Disperse sodium β-alumina grafted aniline in water to obtain a sodium β-alumina grafted aniline suspension.

[0198] Comparative Example 4

[0199] 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:

[0200] E302. Under stirring conditions of 3 rpm, add the sodium persulfate solution into the sodium β-alumina grafted aniline suspension at once, and then continue stirring for 2 h.

[0201] Comparative Example 5

[0202] 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:

[0203] E304. The washed product was vacuum dried at 100°C for 18 h to obtain a composite solid electrolyte.

[0204] In order to verify the advancement of a sodium ion solid-state battery and a preparation method thereof provided in an embodiment of the present invention, in the preparation methods provided in the embodiments and comparative examples, the conductivity of the prepared composite solid electrolyte was detected by a four-probe method; the capacity retention rate (%) of the prepared sodium ion solid-state battery after 500 cycles at 3C at 25°C was detected, and the results are shown in Table 1 below.

[0205]

[0206] From the above table, we can at least draw the following conclusions:

[0207] (1) In Comparative Example 1, the sodium β-alumina was not acidified, and the composite solid electrolyte obtained had a conductivity that was not much different from that of Example 1, but its capacity retention rate was greatly reduced. This indicates that in the composite solid electrolyte obtained in Comparative Example 1, there was only physical adsorption between polyaniline and sodium β-alumina, and polyaniline was not grafted onto the surface of sodium β-alumina, resulting in poor interface stability between the solid electrolyte and the electrode material in the sodium ion solid-state battery, and rapid battery capacity decay. It can be seen that the composite solid electrolyte provided by the embodiment of the present invention, comprising sodium β-alumina (Naβ-Al2O3) grafted polyaniline, can significantly improve the interface stability between the composite solid electrolyte and the electrode material, and slow the battery capacity decay.

[0208] (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 composite solid electrolyte obtained was significantly reduced compared with the embodiment, indicating that when preparing the composite solid electrolyte, the side reaction of aniline and sodium persulfate generated too many by-products that did not have conductive properties, which not only reduced the conductivity of the solid electrolyte, but also affected the interface stability between the solid electrolyte and the electrode material, further leading to a faster capacity decay of the battery. It can be seen from this that the preparation method of the sodium ion solid-state battery provided by the embodiment of the present invention, when preparing the composite solid electrolyte, under the preparation conditions provided by the embodiment of the present invention, can prepare an emeraldine salt with high conductivity, and graft it to sodium β-alumina in a chemically bonded manner, so that the composite solid electrolyte has a very high conductivity, and then in the sodium ion solid-state battery, the composite solid electrolyte and the electrode material have a very high interface stability, and the battery capacity decays slowly.

[0209] It should be noted that the present invention is not limited to the above-mentioned embodiments. The above-mentioned embodiments are merely examples, and any embodiments having substantially the same structure and effect as the technical concept within the scope of the technical solution of the present invention are all included in the technical scope of the present invention. In addition, without departing from the scope of the present invention, other embodiments that can be conceived by those skilled in the art and that combine some of the 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: including composite solid electrolytes; The composite solid electrolyte includes sodium β-alumina grafted polyaniline; The raw materials of the sodium β-alumina grafted 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 to 6:1; The preparation of the composite solid electrolyte comprises the following steps: The acidified sodium β-alumina and aniline are subjected to loading treatment to obtain sodium β-alumina grafted aniline; The sodium β-alumina grafted aniline suspension is mixed with a sodium persulfate solution to obtain sodium β-alumina grafted polyaniline; wherein the pH value of the sodium β-alumina grafted aniline suspension is below 2; The temperature of the sodium β-alumina grafted aniline suspension is 0°C to 5°C; The temperature of the sodium persulfate solution is 0°C to 5°C; The step of mixing the sodium β-alumina grafted aniline suspension and the sodium persulfate solution comprises: dripping the sodium persulfate solution into the sodium β-alumina grafted aniline suspension at a dripping rate of 30 d / min to 60 d / min.

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, characterized in that Satisfy at least one of the following conditions (1) to (2): (1) The porosity of the sodium β-alumina is 30% to 50%; (2) The pore size of the sodium β-alumina is 1 μm to 5 μm.

4. The sodium ion solid-state battery according to claim 1, characterized in that Satisfy at least one of the following conditions (1) to (2): (1) The loading treatment comprises the following steps: mixing the acidified sodium β-alumina and aniline, soaking the mixture, and then air-drying the mixture under stirring; (2) The mixing treatment comprises the following steps: mixing the sodium β-alumina grafted aniline suspension and the sodium persulfate solution under stirring conditions, washing and drying.

5. The sodium ion solid-state battery according to claim 4, characterized in that Satisfy at least one of the following conditions (1) to (3): (1) The mixing and soaking time is 20 min to 30 min; (2) The air-drying time is 6 hours to 12 hours; (3) Repeat the steps of mixing, soaking, and air-drying 2 to 4 times.

6. The sodium ion solid-state battery according to claim 4, characterized in that The drying step comprises: vacuum drying the washed product at 50° C. to 60° C.

7. Use of the sodium ion solid-state battery according to any one of claims 1 to 6 in the field of new energy.

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