A polymer solid-state electrolyte and a solid-state sodium battery based thereon

Abstract

The application provides a polymer solid-state electrolyte and a solid-state sodium battery based on the same, which is prepared from a sodium salt, an antimony-based additive and a high-molecular polymer. The polymer solid-state electrolyte has high ionic conductivity, strong interface compatibility with sodium metal, can effectively inhibit interface side reactions and sodium dendrite growth, and has a simple preparation process, so that the polymer solid-state electrolyte is expected to be applied to industrial production. When the polymer solid-state electrolyte is used in a sodium metal symmetric battery and a sodium||vanadium sodium phosphate (Na3V2(PO4)3) full battery, the battery exhibits low polarization voltage, stable cycle performance and high specific capacity, and has good practical application value.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of sodium ion batteries, and particularly relates to a preparation method and application of a polymer solid-state electrolyte for sodium ion batteries. BACKGROUND

[0002] Compared with the widely used lithium ion battery, the sodium ion battery is expected to be applied in the large-scale energy storage field in the future due to the advantages of rich sodium resource reserves, wide distribution and low cost. The solid-state sodium battery has outstanding advantages in specific energy and safety compared with the liquid-state sodium battery. Among them, the sodium metal negative electrode has the advantages of high mass specific capacity (1166 mAh g-1) and low redox potential (-2.74 V vs SHE), so that the energy density of the solid-state sodium battery can be further improved by using metal sodium as the negative electrode. -1

[0003] The solid-state electrolyte is a key component in the solid-state battery. Compared with the inorganic solid-state electrolyte, the polymer solid-state electrolyte has the advantages of good interface contact, good flexibility and easy processing. In addition, the polymer solid-state electrolyte has many advantages such as good film-forming property, cost-effectiveness and good sodium salt solubility, and has great development potential.

[0004] However, the polymer solid-state electrolyte currently still faces two problems, one is that the room temperature ionic conductivity of the electrolyte is not high, and the other is that the compatibility of the electrolyte and the sodium metal negative electrode is poor. This is mainly because the reduction activity of metal sodium is high, and when the polymer solid-state electrolyte directly contacts with the metal sodium, the interface side reaction is prone to occur. The passivation layer generated by the side reaction at the interface will hinder the transmission of sodium ions, causing the increase of the battery interface impedance and the increase of the battery polarization voltage. In addition, due to the existence of the passivation layer, the concentration polarization on the electrode surface is increased, which induces the growth of sodium dendrites, and even the passivation layer may pierce the polymer solid-state electrolyte film, eventually leading to the failure of the battery.

[0005] In order to solve these problems, researchers mainly adopt two methods: one is to improve the operating temperature of the battery; the other is to introduce additives (such as oxide solid-state electrolyte or sulfide solid-state electrolyte) into the electrolyte to prepare organic-inorganic composite electrolyte. At present, these methods can improve the ionic conductivity of the polymer solid-state electrolyte to some extent, but have limited effect on enhancing the interface compatibility between the polymer solid-state electrolyte and the metal sodium, and the cycle life of the modified polymer solid-state sodium battery is also limited, which is difficult to meet the actual application. Therefore, it is urgent to provide a key technology for preparing a solid-state sodium ion electrolyte, which can not only improve the ionic conductivity of the polymer solid-state electrolyte, but also significantly enhance the interface compatibility between the polymer solid-state electrolyte and the metal sodium, so as to realize the high specific energy, high safety and long life of the solid-state sodium metal battery. SUMMARY ​

[0006] In order to solve the problems of low ionic conductivity of polymer solid-state electrolyte, poor interface compatibility between electrolyte and sodium metal in polymer solid-state sodium metal battery, the application provides a preparation method of polymer solid-state electrolyte with high interface compatibility.

[0007] In order to achieve the purpose, the application adopts the following technical scheme:

[0008] The application first provides a polymer solid-state electrolyte for solid-state sodium battery, which is prepared from a high molecular polymer, a sodium salt and an antimony-based additive.

[0009] The high molecular polymer and the organic solvent are mixed to obtain a polymer precursor solution.

[0010] The sodium salt, the antimony-based additive and the polymer precursor solution are mixed to obtain a polymer solid-state electrolyte precursor slurry.

[0011] The polymer solid-state electrolyte precursor slurry is coated on a mold, and a polymer solid-state electrolyte film is obtained after drying.

[0012] Preferably, the mass fraction of the high molecular polymer in the polymer precursor solution is 5-20 wt%, and the high molecular polymer is selected from one or more of polyethylene oxide, polymethyl methacrylate, polyvinylidene fluoride, acrylic multi-copolymer and polyvinylidene fluoride-hexafluoropropylene.

[0013] Preferably, the mass ratio of the sodium salt to the high molecular polymer is (0.1-2):1, and the sodium salt is selected from one or more of sodium bis(trifluoromethylsulfonyl)imide, sodium bis(fluorosulfonyl)imide, sodium hexafluorophosphate, sodium perchlorate, sodium trifluoromethylsulfonylimide, sodium tetrafluoroborate and sodium difluoro(oxalato)borate.

[0014] Preferably, the mass ratio of the antimony-based additive to the high molecular polymer is (0.01-0.2):1.

[0015] Preferably, the composition of the antimony-based additive contains Sb element and elements (such as O, S, Se, Te or P) capable of forming sodium ion-conducting compounds with sodium metal, and is further preferably selected from one of antimony oxide, antimony sulfide, antimony selenide, antimony telluride, antimony oxysulfide, antimony sulfoselenide, antimony selenotelluride and antimony phosphide.

[0016] Preferably, the thickness of the polymer solid-state electrolyte is 5-500 μm.

[0017] The application also provides a solid-state sodium battery, comprising a positive electrode, a negative electrode and the solid electrolyte prepared from a sodium salt, an antimony-based additive and a high molecular polymer.

[0018] Preferably, the material of the positive electrode is selected from one or more of sodium vanadium phosphate, sodium iron pyrophosphate, Prussian blue analogues and layered oxide positive electrodes, and the negative electrode is selected from one or more of sodium metal negative electrodes, sodium-tin alloy negative electrodes, sodium-bismuth alloy negative electrodes, sodium-antimony alloy negative electrodes and hard carbon negative electrodes.

[0019] The beneficial effects of the application are embodied in:

[0020] The application provides a polymer solid electrolyte prepared from a high molecular polymer, a sodium salt and an antimony-based additive. The antimony-based additive has a strong adsorption effect on the anion in the sodium salt, can effectively promote the dissociation of the sodium salt, and thus improve the ionic conductivity of the electrolyte; further, the antimony-based additive can react with the sodium negative electrode to generate a high-stability interface layer in situ at the electrolyte / negative electrode interface, inhibit the side reaction of the polymer solid electrolyte and the sodium negative electrode; in addition, the sodium-antimony alloy contained in the interface layer has strong sodium affinity, which is conducive to inducing uniform nucleation and deposition of sodium ions. Therefore, the sodium metal full battery assembled from the polymer solid electrolyte of the application has excellent long cycle stability. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 A scanning electron microscope photo of the polymer solid electrolyte film modified by the antimony sulfide additive in Example 1 of the application;

[0022] Figure 2 A scanning electron microscope photo of the unmodified polymer solid electrolyte film in Example 1 of the application;

[0023] Figure 3 A cycle performance graph of the sodium||sodium symmetric battery assembled from the unmodified electrolyte in Example 2 of the application at 60℃;

[0024] Figure 4 A cycle performance graph of the sodium||sodium symmetric battery assembled from the antimony oxide additive modified electrolyte in Example 2 of the application at 60℃;

[0025] Figure 5 A cycle performance graph of the sodium||sodium symmetric battery assembled from the antimony selenide additive modified electrolyte in Example 3 of the application at 60℃;

[0026] Figure 6 A comparison graph of the alternating current impedance of the sodium||sodium symmetric battery assembled from the antimony selenide additive modified electrolyte in Example 3 of the application and the sodium||sodium symmetric battery assembled from the unmodified electrolyte at 60℃;

[0027] Figure 7 Cycle performance plot of the sodium || sodium symmetric battery assembled with the Sb2Te3 additive modified electrolyte of the present application embodiment 4 at 60℃;

[0028] Figure 8 Cycle performance plot of the Na | Sb2Se3@PEO | Na3V2(PO4)3 solid-state sodium battery of the present application embodiment 5 at 60℃. DETAILED DESCRIPTION

[0029] In order to further understand the present application, the preferred embodiments of the present application are described below in conjunction with the examples, but it should be understood that these descriptions are only for further illustrating the features and advantages of the present application, and are not limitations on the claims of the present application.

[0030] In view of the problems of low ionic conductivity of electrolyte, and serious side reactions at the interface between electrolyte and sodium metal negative electrode in the polymer solid-state sodium metal battery in the prior art, the present application provides a polymer solid-state electrolyte. The polymer solid-state electrolyte provided by the present application promotes the dissociation of sodium salt due to the introduction of antimony-based additive, thereby improving the ionic conductivity of the electrolyte; especially through the interface layer generated in situ at the interface by the additive and sodium metal, the side reactions and dendrite growth can be significantly inhibited, and a long-life solid-state sodium metal battery is obtained. Specifically, the present application embodiment discloses a polymer solid-state electrolyte prepared from a high molecular polymer, a sodium salt and an antimony-based additive.

[0031] In the polymer solid-state electrolyte provided by the present application, the antimony-based additive is selected from one of antimony oxide, antimony sulfide, antimony selenide, antimony telluride, antimony oxysulfide, antimony oxyselenide, antimony oxotelluride and antimony phosphide, and the antimony-based additive has the following characteristics: in terms of composition, it contains Sb and elements (such as O, S, Se, Te or P) that can form a sodium ion conductive compound with sodium metal. In specific embodiments, the antimony-based compound is selected from Sb2S3, Sb2O3, Sb2Se3 and Sb2Te3. The present application does not have special restrictions on the source of the antimony-based compound, which can be prepared according to methods well known to those skilled in the art, or can be obtained commercially.

[0032] The sodium salt is selected from one or more of sodium bis(trifluoromethylsulfonyl)imide, sodium bisfluorosulfonylimide, sodium hexafluorophosphate, sodium perchlorate, sodium trifluoromethylsulfonylimide, sodium tetrafluoroborate and sodium difluoro(oxalato)borate.

[0033] The high molecular polymer is mainly used for film formation and sodium ion conduction, and is selected from one or more of polyethylene oxide, polymethyl methacrylate, polyvinylidene fluoride, acrylic multi-component copolymer and polyvinylidene fluoride-hexafluoropropylene.

[0034] The mass ratio of the sodium salt and the high molecular polymer is (0.1-2):1. Further preferably, the mass ratio of the sodium salt and the high molecular polymer is (0.3-1.5):1. The content of the sodium salt is moderately increased, which can enhance the ability of the electrolyte to conduct sodium ions, but due to the decrease of the content of the high molecular polymer, the mechanical stability of the polymer solid electrolyte is decreased, resulting in the decrease of the long cycle stability; the content of the sodium salt is too small, and the content of the high molecular polymer is correspondingly increased, which can improve the flexibility of the polymer solid electrolyte, but the sodium ion conduction rate is decreased, and the ionic conductivity is correspondingly decreased.

[0035] The mass ratio of the antimony-based additive and the high molecular polymer is (0.01-0.2):1. Further preferably, the mass ratio of the antimony-based additive and the high molecular polymer is (0.02-0.15):1. The content of the antimony-based additive is too large, which is beneficial to the formation of a stable interfacial layer, but due to the decrease of the content of the high molecular polymer, the toughness of the polymer solid electrolyte is decreased; the content of the antimony-based additive is too small, and the content of the high molecular polymer is correspondingly increased, which can improve the flexibility of the polymer solid electrolyte, but the ability to promote the dissociation of the sodium salt is decreased, it is difficult to form a stable interfacial layer, resulting in serious interfacial side reactions and deterioration of the battery performance.

[0036] In the present application, the thickness of the polymer solid electrolyte is 5-500 μm. Further preferably, the thickness of the polymer solid electrolyte is 20-100 μm. The thickness of the polymer solid electrolyte is too small, which is beneficial to the rapid transmission of sodium ions, but the mechanical properties are poor, and the ability to inhibit sodium dendrites is weakened; the thickness is too large, the mechanical properties are strong, but it is not conducive to the rapid transmission of sodium ions, resulting in concentration polarization of the battery and increase of the battery impedance.

[0037] Further, the present application provides a preparation method of the polymer solid electrolyte, which comprises the following steps:

[0038] First, the high molecular polymer is added to an organic solvent to prepare a polymer precursor solution. In this process, the organic solvent can be selected from a solvent that can dissolve the high molecular polymer, that is, N-methyl pyrrolidone (NMP), acetone, acetonitrile or N,N-dimethylformamide (DMF), and further preferably acetonitrile. The mass fraction of the high molecular polymer in the polymer precursor solution is 5-20 wt%, and further preferably 8-15 wt%.

[0039] Then, the sodium salt, the antimony-based additive and the polymer precursor solution are mixed by stirring to obtain a polymer solid-state electrolyte precursor slurry; the polymer solid-state electrolyte precursor slurry is coated on a mold, and after drying, a polymer solid-state electrolyte is obtained. The coating method can be performed in a manner known to those skilled in the art, and the present application is not particularly limited, for example, a doctor blade coating, drop coating or spin coating method can be used. The drying is performed by vacuum drying or natural volatilization drying, and specifically, the drying is performed by natural volatilization drying first, and then vacuum drying. The drying temperature is 20-60℃, the natural volatilization drying time is 5-24h, and the vacuum drying time is 4-24h, and further preferably, the natural volatilization drying time is 12-24h, and the vacuum drying time is 6-12h.

[0040] Further, the present application provides a solid-state sodium metal battery, which is obtained by applying the polymer solid-state electrolyte described above to a solid-state sodium battery; specifically, the solid-state sodium battery comprises a polymer solid-state electrolyte, a positive electrode and a negative electrode.

[0041] In the solid-state sodium battery provided by the present application, the material of the positive electrode is selected from one or more of sodium vanadium phosphate, sodium iron pyrophosphate, Prussian blue analogs and layered oxide positive electrodes. In the embodiments of the present application, the material of the positive electrode is selected from sodium vanadium phosphate. The present application does not have a particular limitation on the source of the sodium vanadium phosphate, which can be prepared according to a method known to those skilled in the art, or can be obtained commercially. The negative electrode is selected from one or more of sodium metal negative electrodes, sodium-tin alloy negative electrodes, sodium-bismuth alloy negative electrodes, sodium-antimony alloy negative electrodes and hard carbon negative electrodes. In the embodiments of the present application, the material of the negative electrode is selected from sodium metal negative electrodes, and the present application does not have a particular limitation on the source of the sodium metal, which can be prepared according to a method known to those skilled in the art, or can be obtained commercially.

[0042] The solid-state sodium metal full battery provided by the present application can effectively inhibit the interface side reaction of the electrolyte and the sodium metal negative electrode, promote the transmission of sodium ions at the interface, induce uniform deposition of sodium ions, reduce the interface resistance of the battery, and thus enhance the cycle stability of the solid-state sodium metal full battery.

[0043] In order to further understand the present application, the polymer solid-state electrolyte and the preparation method thereof provided by the present application are described in detail below in conjunction with examples, and the protection scope of the present application is not limited by the following examples.

[0044] Example 1

[0045] 0.2 g of polyethylene oxide was dissolved in acetonitrile to obtain a polymer precursor solution with a mass fraction of 10 wt%, 85 mg of sodium bis(trifluoromethylsulfonyl)imide and 10 mg of antimony sulfide (Sb2S3) were added to the polymer precursor solution and stirred uniformly to obtain a polymer solid electrolyte precursor slurry. The polymer solid electrolyte precursor slurry was coated on a mold, and naturally volatilized and dried at room temperature for more than 12 hours, and then vacuum dried at room temperature for more than 6 hours to remove the solvent. After drying, the antimony sulfide modified polymer solid electrolyte film was cut to a thickness of about 50 μm.

[0046] For comparison, the unmodified polymer solid electrolyte film was also prepared in this embodiment, and the preparation process was basically the same as the above process, and the only difference was that no antimony sulfide additive was added.

[0047] Figure 1 is a scanning electron microscope photo of the antimony sulfide additive modified polymer solid electrolyte film, and it can be seen that the surface of the modified electrolyte film has no obvious pores and is dense and uniform. Figure 2 is a scanning electron microscope photo of the unmodified polymer solid electrolyte film, and it can be seen that the surface of the unmodified polymer solid electrolyte film has obvious pores and is not dense. By comparison Figure 1 and Figure 2 It can be seen that the introduction of antimony sulfide additive can significantly improve the density of the electrolyte, which is conducive to improving the density and mechanical strength of the electrolyte film, thereby inhibiting the growth of dendrites.

[0048] Example 2

[0049] 0.4 g of polyethylene oxide was dissolved in acetonitrile to obtain a polymer precursor solution with a mass fraction of 10 wt%, 0.17 g of sodium bis(trifluoromethylsulfonyl)imide and 20 mg of antimony oxide (Sb2O3) were added to the polymer precursor solution and stirred uniformly to obtain a polymer solid electrolyte precursor slurry. The polymer solid electrolyte precursor slurry was coated on a mold, and naturally volatilized and dried at room temperature for more than 12 hours, and then vacuum dried at room temperature for more than 6 hours to further remove the solvent. After drying, the antimony oxide modified polymer solid electrolyte film was cut to a thickness of about 50 μm.

[0050] For comparison, the unmodified polymer solid electrolyte film was also prepared in this embodiment, and the preparation process was basically the same as the above process, and the only difference was that no antimony sulfide additive was added.

[0051] The polymer solid electrolyte film prepared above was used as an electrolyte, and a sodium metal foil was used as an electrode to assemble a sodium|sodium button type symmetrical battery. Figure 3 is a sodium||sodium symmetrical battery assembled with the unmodified electrolyte at 0.1 mA cm -2The time-voltage curve under the current density, as can be seen from the figure, the polarization voltage of the sodium || sodium symmetric battery is about 200 mV, and the battery short circuit phenomenon appears after less than 10 h of cycle. Figure 4 The time-voltage curve under the current density, as can be seen from the figure, the polarization voltage of the sodium || sodium symmetric battery is about 200 mV, and the battery short circuit phenomenon appears after less than 10 h of cycle. -2 The time-voltage curve under the current density, as can be seen from the figure, the polarization voltage of the sodium || sodium symmetric battery is about 200 mV, and the battery short circuit phenomenon appears after less than 10 h of cycle.

[0052] Example 3

[0053] 0.4 g of polyethylene oxide was dissolved in acetonitrile to obtain a polymer precursor solution with a mass fraction of 10 wt%, 0.17 g of sodium bis-trifluoromethylsulfonylimide and 20 mg of antimony selenide (Sb2Se3) were added to the polymer precursor solution and stirred uniformly to obtain a polymer solid electrolyte precursor slurry. The polymer solid electrolyte precursor slurry was coated on a mold, and then naturally volatilized and dried at room temperature for more than 12 hours, and then vacuum dried at room temperature for more than 6 hours to remove the solvent. After drying, the antimony selenide additive modified polymer solid electrolyte film was cut to obtain a thickness of about 50 μm.

[0054] The polymer solid electrolyte film prepared above was used as an electrolyte, and a sodium metal foil was used as an electrode to assemble a sodium | sodium button-type symmetric battery. Figure 5 The time-voltage curve under the current density, as can be seen from the figure, the polarization voltage of the sodium || sodium symmetric battery is about 200 mV, and the battery short circuit phenomenon appears after less than 10 h of cycle. -2 The time-voltage curve under the current density, as can be seen from the figure, the polarization voltage of the sodium || sodium symmetric battery is about 200 mV, and the battery short circuit phenomenon appears after less than 10 h of cycle. Figure 5 As can be seen from the figure, the polarization voltage of the sodium || sodium symmetric battery assembled by the antimony selenide additive modified polymer solid electrolyte is relatively stable during the cycle process, and when the cycle is 500 h, the polarization voltage is about 20 mV. Figure 6 The time-voltage curve under the current density, as can be seen from the figure, the polarization voltage of the sodium || sodium symmetric battery is about 200 mV, and the battery short circuit phenomenon appears after less than 10 h of cycle. Figure 6 As can be seen from the figure, the addition of antimony selenide can significantly reduce the impedance of the battery, which indicates that the introduction of antimony selenide helps to inhibit the interface side reaction of the electrolyte and sodium metal, and enhances the cycle stability of the battery.

[0055] Example 4

[0056] 0.4 g of polyethylene oxide was dissolved in acetonitrile and stirred until homogeneous to obtain a polymer precursor solution with a mass fraction of 10 wt%. 0.17 g of sodium bis(trifluoromethanesulfonyl)imide and 20 mg of antimony telluride (Sb₂Te₃) were added to the polymer precursor solution and stirred until homogeneous to obtain a polymer solid electrolyte precursor slurry. The polymer solid electrolyte precursor slurry was coated onto a mold and allowed to dry naturally at room temperature for at least 12 hours, followed by vacuum drying at room temperature for at least 6 hours to remove the solvent. After drying, the antimony telluride-modified polymer solid electrolyte membrane was cut to obtain a thickness of approximately 50 μm.

[0057] Using the polymer solid electrolyte membrane prepared above as the electrolyte, sodium metal foil is used as the electrode to assemble a sodium|sodium coin cell. Figure 7 Sodium-to-sodium symmetric batteries (Sb₂Te₃@PEO) assembled using a polymer solid electrolyte modified with antimony telluride additives at 0.1 mA / cm² are described. -2 The time-voltage curve under current density is derived from Figure 7 It can be seen that as the cycling process proceeds, the polarization voltage of the sodium-sodium symmetric cell is relatively small. When the cycle reaches 200h, the polarization voltage is about 20mV.

[0058] Example 5

[0059] 0.7g sodium vanadium phosphate (Na3V2(PO4)3), 0.1g conductive carbon black, and 0.2g PVDF binder (containing a small amount of sodium perchlorate) were mixed, ground, and stirred until homogeneous. This mixture was then coated onto carbon-coated aluminum foil and dried in a vacuum oven at 60℃. After drying, the resulting material was cut to obtain the positive electrode sheet. 0.4g polyethylene oxide was dissolved in acetonitrile and stirred until homogeneous to obtain a polymer precursor solution with a mass fraction of 10wt%. 0.17g sodium bis(trifluoromethanesulfonyl)imide and 20mg antimony selenide (Sb2Se3) were added to the polymer precursor solution and stirred until homogeneous to obtain a polymer solid electrolyte precursor slurry. The polymer solid electrolyte precursor slurry was coated onto a mold and allowed to naturally evaporate and dry at room temperature for at least 12 hours. Then, it was vacuum dried at room temperature for 6 hours to remove the solvent. After drying, the material was cut to obtain a polymer solid electrolyte membrane modified with antimony selenide additives, with a thickness of approximately 50μm.

[0060] A Na|Sb2Se3@PEO|Na3V2(PO4)3 solid sodium battery was assembled using sodium metal foil as the negative electrode. Figure 8 This is the cycle performance curve of a Na|Sb2Se3@PEO|Na3V2(PO4)3 solid sodium battery. The first 5 cycles are at 10 mAg. -1 Activated at a low current density, then changed to 100 mAg. -1 Cycling is performed at a current density. Figure 8 It can be seen that at 100mAg -1The specific capacity of the Na|Sb2Se3@PEO|Na3V2(PO4)3 solid-state sodium battery is about 100 mAh g-1 after 50 cycles at a current density of 0.1 C -1 There is no obvious capacity attenuation, indicating that the compatibility of the modified electrolyte and the sodium vanadium phosphate positive electrode is good.

[0061] The above examples are only used to help understand the method of the present application and its core idea. It should be noted that for those skilled in the art, without departing from the principles of the present application, the present application can be improved and modified, and these improvements and modifications also fall within the scope of the claims of the present application.

Claims

1. A polymer solid-state electrolyte for solid-state sodium batteries, characterized by: The polymer and the organic solvent are mixed to obtain a polymer precursor solution; the sodium salt, the antimony-based additive and the polymer precursor solution are mixed to obtain a polymer solid electrolyte precursor slurry; the polymer solid electrolyte precursor slurry is coated on a mold, and a polymer solid electrolyte for a solid sodium battery is obtained after drying. The antimony-based additive comprises Sb element and one or more elements capable of forming a compound capable of conducting sodium ions with sodium metal; the one or more elements capable of forming the compound capable of conducting sodium ions with sodium metal are one or more of O, S, Se, Te and P; the mass ratio of the sodium salt to the polymer is 0.1-2:1; the mass ratio of the antimony-based additive to the polymer is 0.01-0.2:

1.

2. The polymer solid-state electrolyte for solid-state sodium batteries according to claim 1, characterized by The sodium salt is selected from one or more of sodium bis(trifluoromethylsulfonyl)imide, sodium bisfluorosulfonylimide, sodium hexafluorophosphate, sodium perchlorate, sodium tetrafluoroborate and sodium difluoro(oxalato)borate; the antimony-based additive is selected from one or more of antimony oxide, antimony sulfide, antimony selenide, antimony telluride, antimony oxysulfide, antimony sulfoselenide, antimony selenotelluride and antimony phosphide; the polymer is selected from one or more of poly(ethylene oxide), poly(methyl methacrylate), poly(vinylidene fluoride), acrylic multi-component copolymer and poly(vinylidene fluoride-co-hexafluoropropylene).

3. The polymer solid-state electrolyte for solid-state sodium batteries according to claim 1, characterized by The thickness of the polymer solid electrolyte is 5-500 μm.

4. The polymer solid-state electrolyte for solid-state sodium batteries according to claim 1, characterized by: The mass fraction of the polymer in the polymer precursor solution is 5-20 wt%.

5. A solid-state sodium battery comprising a positive electrode, a negative electrode, and a solid-state electrolyte, characterized in that, The solid electrolyte is the polymer solid electrolyte according to any one of claims 1-4.

6. The solid-state sodium battery of claim 5, wherein, The material of the positive electrode is selected from one or more of sodium vanadium phosphate, sodium iron pyrophosphate, Prussian blue and layered oxide positive electrodes; and the negative electrode is selected from one or more of sodium metal negative electrode, sodium-tin alloy negative electrode, sodium-bismuth alloy negative electrode, sodium-antimony alloy negative electrode and hard carbon negative electrode.

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