Composite solid electrolyte and preparation method and application thereof

Abstract

The invention provides a composite solid electrolyte and a preparation method and application thereof. The composite solid electrolyte is composed of a nitrile polymer solid electrolyte, a sodium salt, a plasticizer, an inorganic electrolyte and an interface coupling agent, wherein the interface coupling agent accounts for 0.5-2% of the total mass of the composite solid electrolyte. The preparation method comprises the following steps: sequentially dissolving and dispersing the components in an inert atmosphere, and finally preparing the high-performance interface modified composite solid electrolyte by combining ultrasonic treatment and vacuum drying technologies. The modified composite solid electrolyte effectively enhances the interfacial compatibility between the organic polymer component and the inorganic component, and overcomes the problem of poor interface bonding between the organic polymer component and the inorganic component. The preparation process is simple and easy to control, and the ionic conductivity of the prepared composite solid electrolyte is remarkably improved. The composite solid electrolyte is applied to an all-solid-state sodium battery, the cycling stability and the rate capability of the battery are greatly improved, and the composite solid electrolyte shows good application prospects and market potential.

Description

Technical Field

[0001] This invention relates to the field of solid electrolyte technology, specifically to a composite solid electrolyte, its preparation method, and its application. Background Technology

[0002] Compared to solid-state lithium-ion batteries, solid-state sodium-ion batteries exhibit significant advantages in terms of resource cost, safety, and low-temperature performance. Currently, the most researched solid-state electrolytes mainly include organic solid electrolytes (such as polyethylene oxide and polyacrylonitrile) and inorganic ceramic electrolytes (such as metal oxides and metal sulfides). However, organic solid electrolytes suffer from low ionic conductivity, narrow voltage windows, and poor high-temperature performance, while inorganic electrolytes exhibit poor flexibility and low-temperature performance.

[0003] Combining organic and inorganic electrolytes can leverage the advantages of both, but poor interfacial compatibility leads to phase separation, severely impacting ion transport efficiency and cycle stability. Current methods to improve interfacial compatibility include surface modification and elemental doping, but these suffer from complex processes, high costs, and insufficient thermal stability. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a composite solid electrolyte, its preparation method, and its applications. This invention introduces maleic anhydride as an interfacial coupling agent grafted onto polycarbonate (ABSPC). The amphiphilic molecular structure of ABSPC effectively bridges organic and inorganic electrolytes. The acrylonitrile segments of the maleic anhydride (ABS) moiety are compatible with the nitrile polymer solid electrolyte matrix, while the carbonate groups of the polycarbonate (PC) moiety form coordination bonds with the surface of the inorganic electrolyte. This enhances the interfacial binding energy, significantly improving the uniformity and ion transport performance of the composite solid electrolyte. Simultaneously, it simplifies the preparation process, eliminating the need for high-temperature sintering, and is compatible with solution casting processes, thus reducing production costs.

[0005] This invention provides a composite solid electrolyte, its preparation method, and its application, using the following technical solution: In one aspect, the present invention provides a method for preparing a composite solid electrolyte, wherein the composite solid electrolyte is composed of a nitrile polymer solid electrolyte, a sodium salt, a plasticizer, an inorganic electrolyte, and an interfacial coupling agent; the preparation method includes the following steps: Step 1): In an inert atmosphere, mix the nitrile polymer solid electrolyte with an organic solvent at a mass ratio of 1:10 and stir for 5-6 hours to completely dissolve the nitrile polymer solid electrolyte and form a homogeneous solution A. Step 2): Add sodium salt to solution A obtained in step 1), with the mass ratio of sodium salt to nitrile polymer solid electrolyte being 1:2. Continue stirring for 1-2 hours to completely dissolve the sodium salt, thus obtaining solution B. Step 3): Add a plasticizer to solution B obtained in step 2), with a mass ratio of plasticizer to polymer solid electrolyte of 1:4-6, and continue stirring for 1-2 hours; then add an inorganic electrolyte, with a mass ratio of inorganic electrolyte to polymer solid electrolyte of 2:5, and stir for 4-5 hours; add 0.5-2% of maleic anhydride-grafted polycarbonate (ABSPC) as an interfacial coupling agent, and stir for 1 hour to form solution C; Step 4): Disperse the solution C obtained in Step 3) evenly by ultrasonication at a frequency of 20-50kHz, then cast it onto a polytetrafluoroethylene (PTFE) or stainless steel substrate, and vacuum dry it at 50-80℃ for 12-30 hours to obtain an interface-modified solid sodium battery composite solid electrolyte.

[0006] Preferably, the nitrile polymer solid electrolyte in step 1) is one or more of polyacrylonitrile (PAN), polymethyl methacrylate (PMAN), poly(acrylonitrile-co-methyl methacrylate) (PAN-co-PMMA), or poly(ethylene glycol acrylonitrile ether) (PEGAN).

[0007] Preferably, the organic solvent in step 1) is one or more of N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), N-methylpyrrolidone (NMP), or dimethylacetamide (DMAc).

[0008] Preferably, the sodium salt in step 2) is one or more of sodium bis(trifluoromethanesulfonyl)imide (NaTFSI), sodium perchlorate (NaClO4), sodium hexafluorophosphate (NaPF6), or sodium tetrafluoroborate (NaBF4).

[0009] Preferably, the plasticizer in step 3) is succinic anionyl nitrile (SN), adiponitrile (ADN), sulfolane, tetraethylene glycol dimethyl ether (TEGDME), or the ionic liquid Pyr. 14 TFSI, ionic liquid EMIMFSI, or ionic liquid Py 14 One or more of TFSI.

[0010] Preferably, the inorganic electrolyte is sodium β-alumina (Na2O·nAl2O3) or Na3Zr2Si2PO4 with a NASCION structure. 12 (NZSPO) or one or more of its doped and modified forms; the particle size of the inorganic electrolyte is 1 nm-10 μm.

[0011] Preferably, the synthesis method of the ABSPC is as follows: acrylonitrile-butadiene-styrene copolymer (ABS) and polycarbonate (PC) are mixed in a mass ratio of ABS:PC = 1:4-6.

[0012] In another aspect, the present invention provides a solid sodium battery composite solid electrolyte, wherein the solid sodium battery composite solid electrolyte is prepared by the above-described preparation method.

[0013] In another aspect, the present invention provides an application of a composite solid electrolyte for use in an all-solid-state sodium battery.

[0014] Compared with the prior art, the beneficial effects of the present invention are: This invention provides an ABS / PC interfacial coupling agent modified composite solid electrolyte, which effectively enhances the interfacial compatibility between the organic polymer solid electrolyte and the inorganic electrolyte, overcoming the problem of poor interfacial bonding between the two. The resulting composite solid electrolyte has high ionic conductivity. When applied to all-solid-state sodium batteries, the cycle stability and rate performance of the batteries are significantly improved. This invention simplifies the preparation process, eliminates the need for high-temperature sintering, is compatible with solution casting processes, and reduces production costs, achieving efficient preparation of organic / inorganic composite solid electrolytes and providing a reliable technical solution for the commercial application of next-generation solid-state sodium batteries. Attached Figure Description

[0015] Figure 1 The composite solid electrolyte film prepared in Example 1 of this invention; Figure 2 The electrochemical impedance spectroscopy and ionic conductivity at room temperature of the composite solid electrolyte prepared in Example 1 of this invention assembled into a symmetrical battery. Figure 3 The composite solid electrolyte prepared in Example 1 of this invention is applied to NaNi 0.33 Fe 0.33 Mn 0.33 The first three-cycle charge-discharge curves of an all-solid-state sodium battery system with O2 positive electrode and metallic sodium negative electrode in the 0.1C rate and 2-4V voltage range; Figure 4 The composite solid electrolyte prepared in Example 1 of this invention is applied to NaNi 0.33 Fe 0.33 Mn 0.33 The all-solid-state sodium battery system with O2 positive electrode and metallic sodium negative electrode exhibits long-cycle charge-discharge performance at 1C rate and 2-4V voltage range. Figure 5 The composite solid electrolyte prepared in Example 1 of this invention is applied to NaNi 0.33 Fe 0.33 Mn 0.33 The first three-cycle charge-discharge curves of an all-solid-state sodium battery system with O2 positive electrode and metallic sodium negative electrode in the 0.1C rate and 2-4.2V voltage range; Figure 6 The composite solid electrolyte prepared in Example 1 of this invention is applied to NaNi0.33 Fe 0.33 Mn 0.33 A fully solid-state sodium battery system with O2 cathode and metallic sodium anode exhibits long-cycle charge-discharge performance at 1C rate and within a 2-4.2V range. Figure 7 The composite solid electrolyte film prepared in Example 2 of this invention; Figure 8 The electrochemical impedance spectroscopy and ionic conductivity at room temperature of the composite solid electrolyte prepared in Example 2 of this invention assembled into a symmetrical battery. Figure 9 The composite solid electrolyte prepared in Example 2 of this invention is applied to NaNi 0.33 Fe 0.33 Mn 0.33 The first three-cycle charge-discharge curves of an all-solid-state sodium battery system with O2 positive electrode and metallic sodium negative electrode in the 0.1C rate and 2-4V voltage range; Figure 10 The composite solid electrolyte prepared in Example 2 of this invention is applied to NaNi 0.33 Fe 0.33 Mn 0.33 The all-solid-state sodium battery system with O2 positive electrode and metallic sodium negative electrode exhibits long-cycle charge-discharge performance at 1C rate and 2-4V voltage range. Figure 11 This is the composite solid electrolyte film obtained in Comparative Example 1 of the present invention without ABSPC interface modification by coupling agent; Figure 12 Electrochemical impedance spectroscopy and ionic conductivity at room temperature of a symmetrical battery assembled from a composite solid electrolyte without ABSPC interface modification prepared in Comparative Example 1 of this invention. Figure 13 The composite solid electrolyte prepared in Comparative Example 1 of this invention without coupling agent ABSPC interface modification is applied to NaNi 0.33 Fe 0.33 Mn 0.33 The first three-cycle charge-discharge curves of an all-solid-state sodium battery system with O2 positive electrode and metallic sodium negative electrode in the 0.1C rate and 2-4.2V voltage range; Figure 14 The composite solid electrolyte prepared in Comparative Example 1 of this invention without coupling agent ABSPC interface modification is applied to NaNi 0.33 Fe 0.33 Mn 0.33 The all-solid-state sodium battery system with O2 positive electrode and metallic sodium negative electrode exhibits long-cycle charge-discharge performance at 1C rate and 2-4.2V voltage range. Detailed Implementation

[0016] To make the present invention more apparent and understandable, preferred embodiments are described in detail below with reference to the accompanying drawings.

[0017] This invention provides a composite solid electrolyte, its preparation method, and its applications. The composite solid electrolyte comprises a nitrile polymer solid electrolyte, a sodium salt, a plasticizer, an inorganic electrolyte, and an interfacial coupling agent, wherein the interfacial coupling agent accounts for 0.5-2% of the total mass of the composite solid electrolyte. Under an inert atmosphere, each component is sequentially dissolved and dispersed, and then subjected to ultrasonic treatment and vacuum drying techniques to finally obtain a high-performance interface-modified composite solid electrolyte. This modified composite solid electrolyte effectively enhances the interfacial compatibility between the organic polymer component and the inorganic component. The preparation process of this invention is simple and easy to control; the ionic conductivity of the prepared composite solid electrolyte is significantly improved; when applied to all-solid-state sodium batteries, the cycle stability and rate performance of the batteries are greatly improved.

[0018] Example 1 This invention provides a method for preparing a composite solid electrolyte, which is composed of a nitrile polymer solid electrolyte, a sodium salt, a plasticizer, an inorganic electrolyte, and an interfacial coupling agent, and includes the following steps: (1) In an inert atmosphere glove box, the nitrile polymer solid electrolyte PAN and the organic solvent DMF are mixed at a mass ratio of 1:10 and magnetically stirred for 5 hours until completely dissolved to form a homogeneous solution A; (2) Add sodium salt NaTFSI to solution A obtained in step (1), with the mass ratio of NaTFSI to PAN being 1:2. Continue stirring for 2 hours to completely dissolve NaTFSI and obtain solution B. (3) Add plasticizer SN to solution B obtained in step (2), with the mass ratio of SN to PAN being 1:5, and continue stirring for 2 hours; then add inorganic electrolyte NZSPO, with the mass ratio of NZSPO to PAN being 2:5, and stir for 5 hours; add maleic anhydride-grafted polycarbonate ABSPC as an interfacial coupling agent at 1% of the total mass of the composite solid electrolyte, and stir for 1 hour to form solution C; (4) The solution C obtained in step (3) was ultrasonically dispersed for 30 minutes (power 300W, frequency 30kHz), then cast onto a PTFE substrate and vacuum dried at 60℃ for 24 hours to form a film, as shown. Figure 1 The thin film shown has a smooth and uniform surface, resulting in an interface-modified composite solid electrolyte.

[0019] Example 2 This invention provides a method for preparing a composite solid electrolyte, which is composed of a nitrile polymer solid electrolyte, a sodium salt, a plasticizer, an inorganic electrolyte, and an interfacial coupling agent, and includes the following steps: (1) In an inert atmosphere glove box, the nitrile polymer solid electrolyte PAN and the organic solvent DMF are mixed at a mass ratio of 1:10 and magnetically stirred for 6 hours until completely dissolved to form a homogeneous solution A; (2) Add sodium salt NaTFSI to solution A obtained in step (1), with the mass ratio of NaTFSI to PAN being 1:2. Continue stirring for 1 hour to completely dissolve NaTFSI and obtain solution B. (3) Add plasticizer SN to solution B obtained in step (2), with the mass ratio of SN to PAN being 1:4, and continue stirring for 2 hours; then add inorganic electrolyte particles NZSPO, with the mass ratio of NZSPO to PAN being 2:5, and stir for 5 hours; add maleic anhydride-grafted polycarbonate ABSPC as an interfacial coupling agent at 2% of the total mass of the composite solid electrolyte, and stir for 1 hour to form solution C; (4) The solution C obtained in step (3) was ultrasonically dispersed for 30 minutes (power 300W, frequency 30kHz), then cast onto a stainless steel substrate and vacuum dried at 60℃ for 24 hours to form a film, as shown. Figure 7 The thin film shown has a smooth and uniform surface, resulting in an interface-modified composite solid electrolyte.

[0020] Examples 3-6 By adjusting the combination of each component in the preparation process (as shown in Table 1), the experimental steps are the same as those in Example 1 for preparing interface-modified composite solid electrolytes.

[0021] Table 1. Combinations and ionic conductivity of the components in the composite solid electrolytes prepared in Examples 3-6 of this invention.

[0022] Comparative Example 1 A method for preparing a composite solid electrolyte without ABSPC interface modification includes the following steps: (1) In an inert atmosphere glove box, the nitrile polymer solid electrolyte PAN and the organic solvent DMF are mixed at a mass ratio of 1:10 and magnetically stirred for 5 hours until completely dissolved to form a homogeneous solution A; (2) Add sodium salt NaTFSI to solution A obtained in step (1), with the mass ratio of NaTFSI to PAN being 1:2. Stir for 2 hours to completely dissolve NaTFSI and obtain solution B. (3) Add plasticizer SN to solution B obtained in step (2), with the mass ratio of SN to PAN being 1:5, and continue stirring for 2 hours; then add inorganic electrolyte particles NZSPO, with the mass ratio of NZSPO to PAN being 2:5, and stir for 5 hours to form solution C that does not contain ABSPC; (4) The ABSPC-free solution C obtained in step (3) was ultrasonically dispersed for 30 minutes (power 300W, frequency 30kHz), then cast onto a PTFE substrate and vacuum dried at 60℃ for 24 hours to form a film. Figure 11 The thin film shown has obvious defects, resulting in a composite solid electrolyte without interface modification by the coupling agent.

[0023] The composite solid electrolytes prepared in Examples 1-6 and Comparative Example 1 were used to assemble batteries, and the following tests were performed: (1) Electrochemical impedance spectroscopy: The symmetrical battery assembly sequence from bottom to top is as follows: positive electrode shell of 2032 type battery, stainless steel gasket (thickness 0.05 mm), composite solid electrolyte prepared in Examples 1-6 and Comparative Example 1 (thickness 50-250 μm), stainless steel gasket (thickness 0.05 mm), stainless steel spring sheet (thickness 1.1 mm), and negative electrode shell of 2032 type battery; the assembled battery is clamped into a battery sealing machine with plastic tweezers and sealed at a pressure of 500-1000 Pa; the sealed battery is clamped into a MultiStat for impedance testing at a frequency of 0.01-1000000 Hz and a temperature of 25-30 °C; then according to the formula (L represents the thickness of the electrolyte, R represents the measured impedance, and A represents the area of ​​the composite electrolyte membrane) The ionic conductivity is calculated. Figure 2 The composite solid electrolyte prepared in Example 1, when assembled into a symmetrical battery, has an electrochemical impedance of 3 Ω and an ionic conductivity of 2.12 mS / cm. Figure 8 The composite solid electrolyte prepared in Example 2, when assembled into a symmetrical battery, has an electrochemical impedance of 2 Ω and an ionic conductivity of 1.87 mS / cm. The composite solid electrolytes prepared in Examples 3-6, when assembled into symmetrical batteries, have electrochemical impedances of 4 Ω, 5 Ω, 3 Ω, and 2 Ω, respectively, and ionic conductivityes as shown in Table 1, which are 1.73 mS / cm, 1.58 mS / cm, 1.95 mS / cm, and 2.21 mS / cm, respectively. Figure 12 The composite solid electrolyte without added coupling agent prepared in Comparative Example 1, when assembled into a symmetrical cell, has an electrochemical impedance of 23 Ω and an ionic conductivity of 1.37 mS / cm.

[0024] (2) Charge and discharge test: The assembly sequence of the all-solid-state sodium battery from bottom to top is as follows: positive electrode shell of the 2032 type battery, stainless steel gasket (thickness of 0.05mm), positive electrode sheet (electrode material NaNi). 0.33 Fe 0.33 Mn 0.33 O2, surface loading is 2-5 mg / cm³ 2The composite solid electrolyte (thickness 50-250μm), sodium negative electrode sheet, stainless steel gasket (thickness 0.05mm), stainless steel spring sheet (thickness 1.1mm), and negative electrode shell of 2032 type battery prepared in Examples 1-6 and Comparative Example 1 were used. The assembled battery was clamped into a battery sealing machine with plastic tweezers and sealed at a pressure of 500-1000pa. After the sealed battery was left to stand for 6-8 hours, it was clamped onto a LANDMon V7.3 at a temperature of 25-30℃ and charged and discharged at voltage ranges of 2-4V and 2-4.2V respectively. It was first activated at a rate of 0.1C for three cycles, and then subjected to long-cycle charge and discharge test at a rate of 1C (where the nominal specific capacity 1C = 100-140mAh / g).

[0025] Charge-discharge tests of the composite solid-state electrolyte prepared in Example 1 assembled into an all-solid-state sodium battery: as follows Figure 3 As shown, under a 0.1C rate and a 2-4V voltage window, the first three charge-discharge cycles showed a specific capacity of 106.5 mAh / g in the first discharge cycle and 106.4 mAh / g in the third discharge cycle, with almost no capacity decay. Figure 4 As shown, under long-cycle charge-discharge at a 1C rate and a voltage window of 2-4V, the discharge capacity is 111.1 mAh / g, and after 300 charge-discharge cycles, the capacity reaches 101 mAh / g, with a capacity retention rate higher than 90% and a coulombic efficiency of 99.8%. Figure 5 As shown, under a 0.1C rate and a voltage window of 2-4.2 V, the specific capacities of the first three charge-discharge cycles were 140 mAh / g, 135 mAh / g, and 129.3 mAh / g, respectively; Figure 6 As shown, under long-cycle charge-discharge at a 1C rate and a voltage window of 2-4.2 V, the discharge capacity is 114.5 mAh / g, and after 300 charge-discharge cycles, the capacity reaches 90.3 mAh / g, with a capacity retention of 78.8% and a coulombic efficiency of 99.8%. Charge-discharge tests of the composite solid-state electrolyte prepared in Example 2 assembled into an all-solid-state sodium battery are as follows: Figure 9 As shown, under the first three charge-discharge cycles at a 0.1C rate and a 2-4V voltage window, the specific capacity of the first discharge cycle was 100.6 mAh / g, and the specific capacity of the third discharge cycle was 100.3 mAh / g, with almost no capacity decay; Figure 10 As shown, under long-cycle charge-discharge at a 1C rate and a voltage window of 2-4V, the discharge capacity is 110.3 mAh / g, and after 300 charge-discharge cycles, the capacity reaches 67.1 mAh / g, with a capacity retention of only 61% and a coulombic efficiency of 97.7%. The charge-discharge test of the all-solid-state sodium battery assembled with the composite solid electrolyte prepared in Comparative Example 1 without coupling agent interface modification is as follows: Figure 13As shown, under the first three charge-discharge cycles at a 0.1C rate and a voltage window of 2-4.2V, the specific capacity of the first discharge cycle was 82.7 mAh / g, and the specific capacity of the third discharge cycle was 79.4 mAh / g, with almost no capacity decay; Figure 14 As shown, under long-cycle charge-discharge at a 1C rate and a voltage window of 2-4.2V, the discharge capacity is 70mAh / g, and after 300 charge-discharge cycles, the capacity reaches 25mAh / g, with a capacity retention rate of only 35.7% and a coulombic efficiency of 98.6%.

[0026] In summary, this invention provides a composite solid electrolyte modified with an ABSPC interfacial coupling agent. The resulting composite solid electrolyte exhibits high ionic conductivity; when applied to all-solid-state sodium batteries, it significantly improves the battery's cycle stability and rate performance; by simplifying the preparation process, eliminating the need for high-temperature sintering, and being compatible with solution casting processes, it reduces production costs and achieves efficient preparation of organic / inorganic composite solid electrolytes, providing a reliable technical solution for the commercial application of next-generation solid-state sodium batteries.

[0027] The foregoing has explained the basic principles, main features, and advantages of this invention. Those skilled in the art should understand that this invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this invention. Various changes and modifications can be made to this invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the invention as claimed.

Claims

1. A method for preparing a composite solid electrolyte, characterized in that, The composite solid electrolyte is composed of a nitrile polymer solid electrolyte, a sodium salt, a plasticizer, an inorganic electrolyte, and an interfacial coupling agent; the preparation method includes the following steps: Step 1): In an inert atmosphere, mix the nitrile polymer solid electrolyte with an organic solvent at a mass ratio of 1:10 and stir for 5-6 hours to completely dissolve the nitrile polymer solid electrolyte and form a homogeneous solution A. Step 2): Add sodium salt to solution A obtained in step 1), with the mass ratio of sodium salt to nitrile polymer solid electrolyte being 1:

2. Continue stirring for 1-2 hours to completely dissolve the sodium salt, thus obtaining solution B. Step 3): Add a plasticizer to solution B obtained in step 2), with the mass ratio of plasticizer to nitrile polymer solid electrolyte being 1:4-6, and continue stirring for 1-2 hours; then add an inorganic electrolyte, with the mass ratio of inorganic electrolyte to nitrile polymer solid electrolyte being 2:5, and stir for 4-5 hours; add 0.5-2% of maleic anhydride-grafted polycarbonate (ABSPC) as an interfacial coupling agent as the total mass of the composite solid electrolyte, and stir for 1 hour to form solution C; Step 4): Disperse the solution C obtained in Step 3) evenly by ultrasonication at a frequency of 20-50kHz, then cast it onto a polytetrafluoroethylene or stainless steel substrate, and vacuum dry it at 50-80℃ for 12-30 hours to obtain an interface-modified composite solid electrolyte.

2. The preparation method according to claim 1, characterized in that, In step 1), the nitrile polymer solid electrolyte is one or more of polyacrylonitrile, polymethyl methacrylate, poly(acrylonitrile-copolymer-methyl methacrylate), or poly(ethylene glycol acrylonitrile ether).

3. The preparation method according to claim 1, characterized in that, The organic solvent in step 1) is one or more of N,N-dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, or dimethylacetamide.

4. The preparation method according to claim 1, characterized in that, In step 2), the sodium salt is one or more of sodium bis(trifluoromethanesulfonyl)imide, sodium perchlorate, sodium hexafluorophosphate, or sodium tetrafluoroborate.

5. The preparation method according to claim 1, characterized in that, In step 3), the plasticizer is succinic acid, adiponitrile, sulfolane, tetraethylene glycol dimethyl ether, or the ionic liquid Pyr. 14 TFSI, ionic liquid EMIMFSI, or ionic liquid Py 14 One or more of TFSI.

6. The preparation method according to claim 1, characterized in that, In step 3), the inorganic electrolyte is sodium β-alumina or Na3Zr2Si2PO4 with a NASCION structure. 12 Or one or more of its doped or modified forms; the particle size of the inorganic electrolyte is 1 nm-10 μm.

7. The preparation method according to claim 1, characterized in that, The synthesis method of ABSPC in step 3) is as follows: acrylonitrile-butadiene-styrene copolymer ABS and polycarbonate PC are mixed at a mass ratio of ABS:PC = 1:4-6.

8. A composite solid electrolyte, characterized in that, The composite solid electrolyte is prepared by the preparation method according to any one of claims 1-7.

9. An application of the composite solid electrolyte as described in claim 8, characterized in that, Used in all-solid-state sodium batteries.

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