A method for preparing an all-solid-state sodium-ion battery and its application.

Abstract

This invention discloses a method for preparing an all-solid-state sodium-ion battery and its application, comprising: injecting a precursor dispersion of a solid electrolyte into a sodium-ion battery cell; and sequentially subjecting it to resting, baking, and encapsulation; the raw materials for preparing the precursor dispersion include modified nano-titanium dioxide; the raw materials for preparing the modified nano-titanium dioxide include nano-titanium dioxide, tannic acid, and polyethyleneimine. This invention proposes a method for preparing an all-solid-state sodium-ion battery and its application. The modified nano-titanium dioxide is well dispersed, and the resulting solid electrolyte has low crystallinity and good performance. The all-solid-state sodium-ion battery assembled from this solid electrolyte exhibits high lithium-ion transport number and stable electrochemical properties.

Description

Technical Field

[0001] This invention relates to the field of sodium-ion battery technology, and in particular to a method for preparing an all-solid-state sodium-ion battery and its application. Background Technology

[0002] Sodium and lithium metal share similar physicochemical properties, and sodium is abundant and inexpensive in the Earth's crust, making sodium batteries a promising trend in future energy storage. However, traditional sodium batteries typically use organic liquid electrolytes, which present safety issues such as leakage, evaporation, and flammability. Furthermore, sodium dendrites can easily form at the negative electrode during cycling, leading to short circuits and, in severe cases, battery explosions. To improve battery safety, all-solid-state electrolytes can be used instead of organic liquid electrolytes. Common solid-state electrolytes include inorganic and organic solid-state electrolytes. Inorganic solid-state electrolytes are difficult to process into stable membranes, while organic polymer electrolytes, despite their flexibility and ease of processing, suffer from low ionic conductivity, hindering their further development and application.

[0003] Therefore, it is urgent to provide an all-solid-state sodium-ion battery with high ionic conductivity. Summary of the Invention

[0004] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes a method for preparing an all-solid-state sodium-ion battery and its application. The modified nano-titanium dioxide is well dispersed, and the all-solid-state sodium-ion battery assembled from this solid electrolyte exhibits high lithium-ion transport number and stable electrochemical properties.

[0005] A method for preparing an all-solid-state sodium-ion battery according to a first aspect of the present invention includes:

[0006] The precursor dispersion of the solid electrolyte is injected into the cell of the sodium-ion battery; and then it is placed, baked and packaged in sequence.

[0007] The raw materials for preparing the precursor dispersion include: modified nano-titanium dioxide;

[0008] The raw materials for preparing the modified nano-titanium dioxide include: nano-titanium dioxide, tannic acid, and polyethyleneimine.

[0009] The method for preparing an all-solid-state sodium-ion battery according to an embodiment of the present invention has at least the following beneficial effects:

[0010] The main reason for the low ionic conductivity of polymers is their high crystallinity, which affects the transport of sodium ions. This invention reduces the crystallinity of polymers and increases amorphous regions by adding modified nano-titanium dioxide, thereby improving ionic conductivity. This invention involves grafting tannic acid and polyethyleneimine onto the surface of nano-titanium dioxide particles. Tannic acid is linked to the amino groups of polyethyleneimine via phenolic hydroxyl groups, utilizing steric hindrance to improve the dispersibility of nano-titanium dioxide. The resulting solid electrolyte precursor dispersion exhibits low crystallinity and good high-temperature thermal stability. Polyethyleneimine contains coordinating nitrogen atoms, which promote sodium dissociation and provide channels for sodium ion transport. The polar groups on the surface of nano-titanium dioxide can act as crosslinking points to promote the crosslinking of tannic acid and polyethyleneimine, increasing the content of amorphous components in the system and facilitating sodium ion transport. By grafting polyethyleneimine onto the nanoparticle surface, a steric hindrance effect is generated between polyethyleneimine segments, inhibiting the crystallization of polyethyleneimine segments. Therefore, the modified nano-titanium dioxide can play a greater role, with significantly improved ionic conductivity. The hydroxyl groups in tannic acid crosslink with sodium ions via coordination bonds to form stable complexes. Through chemical crosslinking, the bonding between molecules is stronger, ensuring uniform deposition of sodium ions and inhibiting the growth of sodium dendrites and the occurrence of side reactions.

[0011] According to some embodiments of the present invention, the method for preparing the modified nano-titanium dioxide includes mixing the nano-titanium dioxide and the tannic acid and then adding polyethyleneimine for reaction.

[0012] According to some embodiments of the present invention, the nano-titanium dioxide is 1 to 2 parts by weight, the tannic acid is 1 to 2 parts by weight, and the polyethyleneimine is 1 to 2 parts by weight.

[0013] According to some embodiments of the present invention, in the preparation method of the modified nano-titanium dioxide, the reaction temperature is 50-80°C.

[0014] According to some embodiments of the present invention, in the preparation method of the modified nano-titanium dioxide, the reaction time is 13-18 hours.

[0015] According to some embodiments of the present invention, the particle size of the nano-titanium dioxide is 100-500 nm.

[0016] According to some embodiments of the present invention, the raw materials for preparing the precursor dispersion of the solid electrolyte further include sodium salt and organic solvent.

[0017] According to some embodiments of the present invention, the method for preparing the precursor dispersion of the solid electrolyte includes: adding the sodium salt and the modified nano-titanium dioxide to an organic solvent and mixing and reacting to obtain the precursor dispersion of the solid electrolyte.

[0018] According to some embodiments of the present invention, the sodium salt includes at least one selected from sodium hexafluorophosphate, sodium perchlorate, sodium tetrafluoroborate, sodium hexafluoroarsenate, sodium bis(fluorosulfonyl)imide, and sodium bis(trifluoromethylsulfonyl)imide.

[0019] According to some embodiments of the present invention, the concentration of the sodium salt solution is 0.7–1 mol / L. -1 .

[0020] According to some embodiments of the present invention, the temperature at which the sodium salt and the modified nano-titanium dioxide are added to the organic solvent for mixing and reaction is 50-60°C.

[0021] According to some embodiments of the present invention, the sodium salt and the modified nano-titanium dioxide are added to the organic solvent and reacted for 1 to 2 hours.

[0022] According to some embodiments of the present invention, the organic solvent includes at least one selected from acetonitrile, acetone, N-methylpyrrolidone, N,N-dimethylacetamide, and tetrahydrofuran.

[0023] According to some embodiments of the present invention, the polymer substrate comprises polyethylene glycol.

[0024] According to some embodiments of the present invention, the modified nano-titanium dioxide accounts for 5 to 15% of the precursor dispersion of the solid electrolyte by weight percentage.

[0025] According to some embodiments of the present invention, the modified nano-titanium dioxide accounts for 9 to 11% of the precursor dispersion of the solid electrolyte by weight percentage.

[0026] When the content of modified nano-titanium dioxide is too low, the interfacial impedance in the system is too high, and the ionic conductivity is low. When the content of modified nano-titanium dioxide is too high, due to the excessive amount of filler, the particles are poorly dispersed and prone to agglomeration. The large-volume block filler will become an obstacle to ion transport, thus reducing the ionic conductivity again.

[0027] According to some embodiments of the present invention, the positive electrode sheet includes a positive current collector and a positive active material layer coated on the positive current collector.

[0028] According to some embodiments of the present invention, the positive current collector is aluminum foil.

[0029] According to some embodiments of the present invention, the positive electrode active material layer includes a positive electrode active material, a first conductive agent, and a first binder.

[0030] According to some embodiments of the present invention, the positive electrode active material includes at least one of Prussian blue, sodium vanadium phosphate, and sodium iron phosphate.

[0031] According to some embodiments of the present invention, the first conductive agent includes at least one of conductive graphite, carbon nanotubes and graphene.

[0032] According to some embodiments of the present invention, the first adhesive comprises polyvinylidene fluoride or styrene-butadiene rubber.

[0033] According to some embodiments of the present invention, the negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer coated on the negative electrode current collector.

[0034] According to some embodiments of the present invention, the negative electrode current collector comprises aluminum foil or copper foil.

[0035] According to some embodiments of the present invention, the negative electrode active material layer includes a negative electrode active material, a second conductive agent, and a second binder.

[0036] According to some embodiments of the present invention, the negative electrode active material comprises hard carbon and / or soft carbon.

[0037] According to some embodiments of the present invention, the second conductive agent includes at least one of conductive graphite, carbon nanotubes, and graphene.

[0038] According to some embodiments of the present invention, the second adhesive comprises any one of polyvinylidene fluoride, styrene-butadiene rubber, and sodium alginate.

[0039] An all-solid-state sodium-ion battery according to an embodiment of a second aspect of the present invention, wherein the all-solid-state sodium-ion battery is prepared by the method described above. Detailed Implementation

[0040] The embodiments of the present invention are described in detail below, with examples of the embodiments shown below, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The following examples are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention. Unless otherwise specified, specific conditions in the embodiments are performed under conventional conditions or conditions recommended by the manufacturer. Reagents or instruments used, unless otherwise specified, are all conventional products that can be purchased commercially.

[0041] Example 1

[0042] This embodiment discloses a method for preparing an all-solid-state sodium-ion battery, specifically as follows:

[0043] The preparation method of modified nano-titanium dioxide in this embodiment is as follows:

[0044] A1: Weigh a certain amount of nano-titanium dioxide (100nm particle size) to be coated, add Tris buffer and sonicate for 20 minutes. Then weigh tannic acid, dissolve it in Tris buffer, pour it into the previously dispersed nano-titanium dioxide solution, and rinse the beaker with a small amount of Tris buffer to remove any remaining solution. Cover the beaker with plastic wrap, make holes to allow oxygen to enter, and ensure that the concentration of tannic acid is 2g / L and the concentration of nano-titanium dioxide is 1g / L.

[0045] After sonicating the mixture for 15 minutes, it was placed in a water bath at 25°C and magnetically stirred at 180 r / min for 1 hour. After the reaction was completed, it was washed with deionized water and centrifuged twice at 8000 r / min for 15 minutes. After freeze-drying in a freeze dryer, it was ground to obtain tannic acid-coated titanium dioxide particles.

[0046] A2: First, polyethyleneimine was dissolved in Tris solution. Tannic acid-coated titanium dioxide particles were weighed, stirred evenly, and reacted in a 50°C water bath for 13 hours at a speed of 200 r / min. After the reaction was completed, the mixture was dried at 50°C to obtain modified nano-titanium dioxide with a polyimide concentration of 1.5 g / L.

[0047] A3: The initiator azobisisobutyronitrile (AIBN) is added to polyethylene glycol (PEG), wherein the mass of AIBN is approximately 1 wt% of PEG. The mixture is then mechanically stirred at 70°C for about 30 min. Acetone containing 0.8 mol / L NaClO4 (concentration calculated based on the total volume of PEG) is added, followed by 10% modified nano-titanium dioxide based on the total mass of the liquid mixture. The mixture is then reacted at 50°C for 1 h to obtain a precursor dispersion of the solid electrolyte.

[0048] Preparation of the positive electrode sheet:

[0049] B1: Prussian blue, conductive graphite, and polyvinylidene fluoride binder are dispersed in N-methylpyrrolidone (NMP) diluent at a weight ratio of 90:5:5 to obtain a positive electrode slurry. The positive electrode slurry is evenly coated on both sides of an aluminum foil using a coating machine. After rolling and slitting, a positive electrode sheet is obtained. Finally, it is baked and vacuum dried for later use.

[0050] Preparation of negative electrode sheet:

[0051] C1: The negative electrode active material hard carbon, conductive graphite conductive agent and styrene-butadiene rubber binder are mixed evenly in a weight ratio of 88:3:9, and then dispersed in deionized water to obtain a negative electrode slurry; the negative electrode slurry is evenly coated on both sides of copper foil using a coating machine, and after rolling and cutting, a negative electrode sheet is obtained, and finally baked and vacuum dried for use.

[0052] Fabrication of all-solid-state sodium-ion batteries:

[0053] D1: A bare cell is obtained by stacking positive and negative electrode sheets. The bare cell is then encapsulated with an aluminum-plastic film to obtain a sodium-ion cell. After baking, the sodium-ion cell is injected with a liquid mixture and left to stand, allowing the liquid mixture to fully wet the cell electrode sheets and the precursor dispersion of the solid electrolyte. Heating at 65°C for 3 hours causes the liquid mixture to polymerize and fuse with the precursor dispersion of the solid electrolyte, resulting in an unactivated solid-state sodium-ion battery. After formation, degassing, and vacuum encapsulation, an all-solid-state sodium-ion battery is obtained.

[0054] Example 2

[0055] This embodiment discloses a method for preparing an all-solid-state sodium-ion battery. The difference between this embodiment and Embodiment 1 is that in step A3, modified nano-titanium dioxide is added at 5% of the total mass of the liquid mixture, while the other conditions are the same.

[0056] The preparation method of modified nano-titanium dioxide in this embodiment is as follows:

[0057] A1: Weigh a certain amount of nano-titanium dioxide (100nm particle size) to be coated, add Tris buffer and sonicate for 20 minutes. Then weigh tannic acid, dissolve it in Tris buffer, pour it into the previously dispersed nano-titanium dioxide solution, and rinse the beaker with a small amount of Tris buffer to remove any remaining solution. Cover the beaker with plastic wrap, make holes to allow oxygen to enter, and ensure that the concentration of tannic acid is 2g / L and the concentration of nano-titanium dioxide is 1g / L.

[0058] After sonicating the mixture for 15 minutes, it was placed in a water bath at 25°C and magnetically stirred at 180 r / min for 1 hour. After the reaction was completed, it was washed with deionized water and centrifuged twice at 8000 r / min for 15 minutes. After freeze-drying in a freeze dryer, it was ground to obtain tannic acid-coated titanium dioxide particles.

[0059] A2: First, polyethyleneimine was dissolved in Tris solution. Tannic acid-coated titanium dioxide particles were weighed, stirred evenly, and reacted in a 50°C water bath for 13 hours at a speed of 200 r / min. After the reaction was completed, the mixture was dried at 50°C to obtain modified nano-titanium dioxide with a polyimide concentration of 1.5 g / L.

[0060] A3: The initiator azobisisobutyronitrile (AIBN) is added to polyethylene glycol (PEG), wherein the mass of AIBN is approximately 1 wt% of PEG. The mixture is then mechanically stirred at 70°C for approximately 30 min. Acetone containing 0.8 mol / L NaClO4 (concentration calculated based on the total volume of PEG) is added, followed by 5% modified nano-titanium dioxide based on the total mass of the liquid mixture. The mixture is then reacted at 50°C for 1 h to obtain a precursor dispersion of the solid electrolyte.

[0061] Preparation of the positive electrode sheet:

[0062] B1: Prussian blue, conductive graphite, and polyvinylidene fluoride binder are dissolved in N-methylpyrrolidone (NMP) diluent at a weight ratio of 90:5:5 to obtain a positive electrode slurry. The positive electrode slurry is evenly coated on both sides of an aluminum foil using a coating machine. After rolling and slitting, a positive electrode sheet is obtained. Finally, it is baked and vacuum dried for later use.

[0063] Preparation of negative electrode sheet:

[0064] C1: The negative electrode active material hard carbon, conductive graphite conductive agent and styrene-butadiene rubber binder are mixed evenly in a weight ratio of 88:3:9, and then dispersed in deionized water to obtain a negative electrode slurry; the negative electrode slurry is evenly coated on both sides of copper foil using a coating machine, and after rolling and cutting, a negative electrode sheet is obtained, and finally baked and vacuum dried for use.

[0065] Fabrication of all-solid-state sodium-ion batteries:

[0066] D1: A bare cell is obtained by stacking positive and negative electrode sheets. The bare cell is then encapsulated with an aluminum-plastic film to obtain a sodium-ion cell. After baking, the sodium-ion cell is injected with a liquid mixture and left to stand, allowing the liquid mixture to fully wet the cell electrode sheets and the precursor dispersion of the solid electrolyte. Heating at 65°C for 3 hours causes the liquid mixture to polymerize and fuse with the precursor dispersion of the solid electrolyte, resulting in an unactivated solid-state sodium-ion battery. After formation, degassing, and vacuum encapsulation, an all-solid-state sodium-ion battery is obtained.

[0067] Example 3

[0068] This embodiment discloses a method for preparing an all-solid-state sodium-ion battery. The difference between this embodiment and Embodiment 1 is that in step A3, modified nano-titanium dioxide is added at 15% of the total mass of the liquid mixture, while the other conditions are the same.

[0069] This embodiment discloses a method for preparing an all-solid-state sodium-ion battery, specifically as follows:

[0070] The preparation method of modified nano-titanium dioxide in this embodiment is as follows:

[0071] A1: Weigh a certain amount of nano-titanium dioxide (100nm particle size) to be coated, add Tris buffer and sonicate for 20 minutes. Then weigh tannic acid, dissolve it in Tris buffer, pour it into the previously dispersed nano-titanium dioxide solution, and rinse the beaker with a small amount of Tris buffer to remove any remaining solution. Cover the beaker with plastic wrap, make holes to allow oxygen to enter, and ensure that the concentration of tannic acid is 2g / L and the concentration of nano-titanium dioxide is 1g / L.

[0072] After sonicating the mixture for 15 minutes, it was placed in a water bath at 25°C and magnetically stirred at 180 r / min for 1 hour. After the reaction was completed, it was washed with deionized water and centrifuged twice at 8000 r / min for 15 minutes. After freeze-drying in a freeze dryer, it was ground to obtain tannic acid-coated titanium dioxide particles.

[0073] A2: First, polyethyleneimine was dissolved in Tris solution. Tannic acid-coated titanium dioxide particles were weighed, stirred evenly, and reacted in a 50°C water bath for 13 hours at a speed of 200 r / min. After the reaction was completed, the mixture was dried at 50°C to obtain modified nano-titanium dioxide with a polyimide concentration of 1.5 g / L.

[0074] A3: The initiator azobisisobutyronitrile (AIBN) is added to polyethylene glycol (PEG), wherein the mass of AIBN is approximately 1 wt% of PEG. The mixture is then mechanically stirred at 70°C for about 30 min. Acetone containing 0.8 mol / L NaClO4 (concentration calculated based on the total volume of PEG) is added, followed by 15% modified nano-titanium dioxide based on the total mass of the liquid mixture. The mixture is then reacted at 50°C for 1 h to obtain a precursor dispersion of the solid electrolyte.

[0075] Preparation of the positive electrode sheet:

[0076] B1: Prussian blue, conductive graphite, and polyvinylidene fluoride binder are dissolved in N-methylpyrrolidone (NMP) diluent at a weight ratio of 90:5:5 to obtain a positive electrode slurry. The positive electrode slurry is evenly coated on both sides of an aluminum foil using a coating machine. After rolling and slitting, a positive electrode sheet is obtained. Finally, it is baked and vacuum dried for later use.

[0077] Preparation of negative electrode sheet:

[0078] C1: The negative electrode active material hard carbon, conductive graphite conductive agent and styrene-butadiene rubber binder are mixed evenly in a weight ratio of 88:3:9, and then dispersed in deionized water to obtain a negative electrode slurry; the negative electrode slurry is evenly coated on both sides of copper foil using a coating machine, and after rolling and cutting, a negative electrode sheet is obtained, and finally baked and vacuum dried for use.

[0079] Fabrication of all-solid-state sodium-ion batteries:

[0080] D1: A bare cell is obtained by stacking positive and negative electrode sheets. The bare cell is then encapsulated with an aluminum-plastic film to obtain a sodium-ion cell. After baking, the sodium-ion cell is injected with a liquid mixture and left to stand, allowing the liquid mixture to fully wet the cell electrode sheets and the precursor dispersion of the solid electrolyte. Heating at 65°C for 3 hours causes the liquid mixture to polymerize and fuse with the precursor dispersion of the solid electrolyte, resulting in an unactivated solid-state sodium-ion battery. After formation, degassing, and vacuum encapsulation, an all-solid-state sodium-ion battery is obtained.

[0081] Comparative Example 1

[0082] This comparative example discloses an all-solid-state sodium-ion battery. The difference between this comparative example and Example 1 is that polyethyleneimine was not added, while the other conditions are the same.

[0083] Comparative Example 2

[0084] This comparative example discloses an all-solid-state sodium-ion battery. The difference between this comparative example and Example 1 is that tannic acid was not added, while the other conditions are the same.

[0085] Test Example 1

[0086] The all-solid-state sodium-ion batteries prepared in the above embodiments and comparative examples were subjected to performance tests.

[0087] The rate performance of the all-solid-state sodium-ion batteries prepared in Examples 1-4 and Comparative Examples 1-2 was tested respectively. The specific test methods are as follows:

[0088] At room temperature, the finished battery cell is charged to 3.8V using a constant current and constant voltage of 0.5C (cutoff current 0.02C), and then discharged to 2.0V at 0.2C, resulting in C1. The cell is then fully charged again using the same charging method, and then discharged to 2.0V at 2C, resulting in C2. The discharge rate ratio = C2 / C1 * 100%.

[0089] The test results are shown in Table 1.

[0090] Table 1 Battery Performance Test

[0091]

[0092]

[0093] Test Example 2

[0094] The all-solid-state sodium-ion batteries prepared in the above embodiments and comparative examples were subjected to resistance and conductivity tests.

[0095] The electrochemical window was obtained using linear sweep voltammetry (LSV) with a Li / SPE / SS cell. A potential (relative to the Li electrode) was applied to the cell, and the potential of the working electrode SS was scanned at a certain rate. The horizontal and vertical axes of the scan curve represent voltage and current, respectively. If the cell is in a steady state, the current does not change with the increase of voltage and remains essentially zero. The potential corresponding to the inflection point or peak of the current sharp increase is the electrochemical window of the polymer solid electrolyte. During the test, the scan rate was 0.01 V / s, and the scan voltage range was 2.5 V-8 V vs Li+ / Li.

[0096] The lithium-ion transference number (LTN) of a solid electrolyte is the proportion of lithium ions that occupy all the ions transported between the positive and negative electrodes. It largely represents the electrochemical performance of a lithium battery, and its proportion directly reflects the battery's performance. The LTN is obtained using the steady-state constant voltage-current method (CA), employing a Li / SPE / Li battery. A small constant potential is applied to the battery, and the change in response current over time is recorded. The current is maximum at initial polarization; the initial current *lo* is recorded. After reaching steady state, the steady-state current *Iss* is recorded. The LTN can be calculated using the formula t0. + =I ss / I0 calculates to:

[0097] Where t represents the lithium ion transference number of the solid electrolyte, I0 represents the current at the beginning of polarization, and I ss This represents the current after reaching steady state. The applied voltage was constant at 50mV during the test.

[0098] Table 2 shows the resistance and conductivity tests performed on the batteries.

[0099]

[0100] The difference between Comparative Example 1 and Example 1 is that: polyethyleneimine was not added. Polyethyleneimine contains coordinating atoms N, which can promote the dissociation of sodium and provide a channel for the transport of sodium ions. Under the conditions of Comparative Example 1, the conductivity decreased.

[0101] The difference between Comparative Example 2 and Example 1 is that tannic acid was not added. Tannic acid is linked to the amino group of polyethyleneimine through phenolic hydroxyl groups, which improves the dispersibility of nano-titanium dioxide by utilizing the steric hindrance effect. The resulting solid electrolyte precursor dispersion has low crystallinity and good high-temperature thermal stability. In addition, the hydroxyl groups in tannic acid crosslink with sodium ions through coordination bonds to form a stable complex. Through chemical crosslinking, the bonding between molecules is stronger, which ensures the uniform deposition of sodium ions and inhibits the growth of sodium dendrites and the occurrence of side reactions. The lack of tannic acid will also affect the rate performance and conductivity of the battery.

[0102] This invention reduces polymer crystallinity, increases amorphous regions, and improves ionic conductivity by adding modified nano-titanium dioxide. Grafting tannic acid and polyethyleneimine onto the surface of nano-titanium dioxide particles enhances the dispersibility of the nano-titanium dioxide by utilizing steric hindrance. The resulting solid electrolyte precursor dispersion exhibits low crystallinity and good high-temperature thermal stability. Polyethyleneimine contains coordinating nitrogen atoms, which promote sodium dissociation and provide channels for sodium ion transport. The polar groups on the surface of nano-titanium dioxide act as crosslinking points, promoting the crosslinking of tannic acid and polyethyleneimine, increasing the content of amorphous components in the system, and facilitating sodium ion transport. Grafting polyethyleneimine onto the nanoparticle surface generates steric hindrance between polyethyleneimine segments, inhibiting the crystallization of polyethyleneimine segments. Therefore, the modified nano-titanium dioxide can play a greater role, with significantly improved ionic conductivity. The hydroxyl groups in tannic acid crosslink with sodium ions through coordination bonds to form stable complexes. Through chemical crosslinking, the bonding between molecules is strengthened, ensuring uniform deposition of sodium ions and inhibiting the growth of sodium dendrites and the occurrence of side reactions.

Claims

1. A method for preparing an all-solid-state sodium-ion battery, characterized by, The application relates to a preparation method of a full-solid-state sodium ion battery. A precursor dispersion liquid of a solid-state electrolyte is injected into an electric cell of a sodium ion battery; and then the electric cell is sequentially placed, baked and packaged; Preparation raw materials of the precursor dispersion liquid of the solid-state electrolyte include modified nano-titanium dioxide; Preparation raw materials of the modified nano-titanium dioxide include nano-titanium dioxide, tannic acid and polyethylene imine; The preparation method of the precursor dispersion liquid of the solid-state electrolyte is as follows: A1: nano-titanium dioxide is weighed, added into Tris buffer solution and ultrasonically treated for 20 min, then tannic acid is weighed, added into the Tris buffer solution, dissolved, poured into the dispersed nano-titanium dioxide solution, the residual solution in the beaker is washed with the Tris buffer solution, the mouth of the beaker is covered with a preservative film, a hole is punched to ensure the entry of oxygen, the concentration of the tannic acid is 2 g / L, the concentration of the nano-titanium dioxide is 1 g / L, the mixed solution is ultrasonically treated for 15 min, then is placed in a 25 DEG C water bath environment, is magnetically stirred at a rotating speed of 180 r / min for 1 h, after the reaction is completed, is centrifuged twice with deionized water as a washing liquid at a rotating speed of 8000 r / min for 15 min, is freeze-dried in a freeze dryer and then ground, so that tannic acid-coated titanium dioxide particles are obtained; A2: polyethylene imine is dissolved in a Tris solution, tannic acid-coated titanium dioxide particles are weighed, uniformly stirred and then reacted in a 50 DEG C water bath environment for 13 h at a rotating speed of 200 r / min, after the reaction is completed, the mixture is dried at 50 DEG C, so that modified nano-titanium dioxide is obtained, the concentration of the polyethylene imine is 1.5 g / L; A3: an initiator azobisisobutyronitrile is added into polyethylene glycol, the mass of the azobisisobutyronitrile is 1 wt% of the polyethylene glycol, then the mixed system of the initiator azobisisobutyronitrile and the polyethylene glycol is mechanically stirred and polymerized at 70 DEG C for 30 min, 0.8 mol / L NaClO4 dispersed in acetone is added, 10% of the modified nano-titanium dioxide based on the total mass of the liquid mixture is added, and then the mixture is reacted at 50 DEG C for 1 h, so that the precursor dispersion liquid of the solid-state electrolyte is prepared.

2. An all-solid-state sodium-ion battery, characterized by: The full-solid-state sodium ion battery is prepared by the preparation method in claim 1.

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