Preparation method and application of solid electrolyte
By uniformly mixing inorganic fillers into an organic polymer electrolyte, a composite solid electrolyte membrane is prepared, which solves the problems of low ionic conductivity and poor mechanical stability in the prior art. This achieves high-efficiency battery performance and a simple preparation process, making it suitable for large-scale production.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-24
- Publication Date
- 2026-03-31
AI Technical Summary
The existing solid electrolytes have low ionic conductivity and poor mechanical stability, which are difficult to balance, and the preparation process is complicated, which limits their application in batteries.
Inorganic fillers were uniformly mixed in an organic polymer electrolyte solution using mechanical stirring to prepare a composite solid electrolyte precursor. A solid electrolyte membrane was then formed, and mesoporous metal oxides were used to enhance the dissociation and absorption of lithium salts by N,N-dimethylformamide solvent, thereby improving electrolyte performance.
The preparation process is simple and suitable for large-scale production. The composite solid electrolyte membrane has excellent flexibility, high ionic conductivity and mechanical strength, reduces polarization and side reactions during battery cycling, and exhibits excellent rate performance.
Smart Images
Figure CN121769256A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the technical field of solid electrolytes, specifically relating to a method for preparing a polymer solid electrolyte with composite inorganic filler, as well as the polymer solid electrolyte membrane and solid alkali metal battery. Background Technology
[0002] With the increasing demands for energy density and safety from electric vehicles, large-scale energy storage, and portable electronic devices, the thermal runaway risk posed by the flammable and leak-prone organic liquid electrolytes in traditional liquid batteries is becoming increasingly prominent, posing a key bottleneck to their further development. Solid-state electrolytes have attracted much attention due to their high safety, good mechanical strength, and excellent electrochemical stability, and have broad application prospects, especially in wearable devices, flexible electronics, and electric vehicles.
[0003] To date, successfully developed solid-state electrolytes include organic polymer electrolytes and inorganic oxide or sulfur compound electrolytes. Compared to inorganic electrolytes, polymer electrolytes offer better mechanical flexibility and lower manufacturing costs, which is beneficial for large-scale industrial production while further improving battery safety. However, the ionic conductivity and mechanical properties of polymer electrolytes are often difficult to balance, limiting their applications. Summary of the Invention
[0004] [Technical problem to be solved]
[0005] To address the practical application problems of the aforementioned materials, this invention provides a polymer solid electrolyte with composite inorganic fillers and its preparation method, thereby combining the advantages of organic polymer electrolytes and inorganic materials, and solving the defects of current solid electrolytes such as low ionic conductivity, poor mechanical stability, and difficulty in processing and preparation.
[0006] [Technical Solution]
[0007] To achieve the above objectives, the present invention adopts the following technical solution:
[0008] (1) Preparation of inorganic fillers;
[0009] (2) Preparation of organic polymer electrolyte solution;
[0010] (3) The inorganic filler is uniformly mixed in the organic polymer electrolyte solution by mechanical stirring to obtain a solid electrolyte precursor;
[0011] (4) The solid electrolyte precursor is shaped to obtain a solid electrolyte membrane.
[0012] In some embodiments, the inorganic filler is a metal-doped mesoporous metal oxide.
[0013] In some implementations, step (1) includes the following sub-steps:
[0014] A powder precursor is obtained by grinding a doped metal A source, a metal B source, a surfactant, and a nitrate evenly; and the powder precursor is then heat-treated and washed with water to remove impurities, in order to obtain the inorganic filler.
[0015] In specific implementation schemes, the doped metal elements include one or more of iron, cobalt, nickel, copper, manganese, and tin. The raw materials include one or more of metal sulfates, metal nitrates, and metal chlorides; the metal oxides include one or more of cerium oxide, tin oxide, and manganese oxide. Alternatively, the raw materials may include one or more of metal sulfates, nitrates, and chlorides; the surfactants may include one or more of poloxamer, polyethylene glycol, polyethylene oxide, hexadecyltrimethylammonium bromide, and polyoxyethylene fatty alcohol ethers; and the nitrates may include one or more of lithium nitrate, potassium nitrate, and sodium nitrate.
[0016] In a specific implementation plan, the heat treatment step is carried out at 150 to 600°C for 5 to 12 hours.
[0017] In some implementations, step (2) includes the following sub-steps:
[0018] One or more alkali metal salts, such as lithium, sodium, or potassium salts, are dissolved in N,N-dimethylformamide to provide an alkali metal salt solution; an organic polymer is added to the alkali metal salt solution and heated to melt the organic polymer and obtain an organic polymer electrolyte solution.
[0019] In a specific embodiment, the lithium salt includes one or more of lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium difluorooxalate borate, lithium di(oxalate borate), and lithium perchlorate; the sodium salt includes one or more of sodium bis(fluorosulfonyl)imide, sodium bis(trifluoromethanesulfonyl)imide, sodium difluorooxalate borate, sodium di(oxalate borate), and sodium perchlorate; the potassium salt includes one or more of potassium bis(fluorosulfonyl)imide, potassium bis(trifluoromethanesulfonyl)imide, potassium difluorooxalate borate, potassium di(oxalate borate), and potassium perchlorate; and / or, the organic polymer is selected from polyethylene oxide, polyvinylidene fluoride-hexafluoropropylene, polyvinyl difluoroethylene, or succinate.
[0020] In a specific implementation plan, the mass ratio of alkali metal salt to organic polymer is 1:(1-10).
[0021] In some implementations, the magnetic stirring speed in step (3) is in the range of 500 to 1000 rpm, and the mechanical stirring time is 3 to 12 hours.
[0022] In a specific implementation plan, the mass ratio of inorganic filler to organic polymer is 1:(20-100).
[0023] In some implementations, step (4) includes placing the composite solid electrolyte precursor into a mold and then drying and shaping it.
[0024] In a specific implementation, the mold is configured as a polyetheretherketone mold to facilitate demolding; and / or, wherein the drying molding is carried out at 50 to 100°C for 6 to 15 hours.
[0025] In a second aspect of the invention, a composite solid electrolyte prepared by the above method is provided, wherein the mass of the inorganic filler accounts for 1% to 20% of the mass of the composite solid electrolyte membrane.
[0026] In a third aspect of the present invention, a solid-state alkali metal battery is provided, comprising: a positive electrode made of lithium iron phosphate; and a negative electrode made of lithium.
[0027] A solid electrolyte membrane located between the positive and negative electrodes, and made of a solid electrolyte prepared by the above method or a solid electrolyte as described above.
[0028] Compared with the prior art, the beneficial effects of the present invention are:
[0029] (1) Compared with the preparation methods of the prior art, the method of this application is simpler and more convenient, with simple preparation process and low equipment requirements, and is suitable for large-scale preparation;
[0030] (2) The composite solid electrolyte membrane obtained by the method of this application has excellent flexibility, high ionic conductivity and mechanical strength, and combines the advantages of inorganic fillers and organic polymers. It can reduce polarization and side reactions during battery cycling and has high ion conduction efficiency.
[0031] (3) When the flexible composite solid electrolyte membrane of the present invention is assembled into a solid lithium alkali metal battery, the battery exhibits excellent rate performance, with high capacity and slow decay at high rate. [Image Description]
[0032] Figure 1 This is a scanning electron microscope image of the inorganic filler powder prepared in Example 1 of the present invention;
[0033] Figure 2 This is a schematic diagram of the composite solid electrolyte membrane prepared in Example 1 of the present invention when it is laid flat;
[0034] Figure 3 This is a schematic diagram of the thickness test of the composite solid electrolyte membrane prepared in Example 1 of the present invention;
[0035] Figure 4 This is a potentiostatic polarization curve of the composite solid electrolyte membrane prepared in Example 1 of the present invention.
[0036] Figure 5 This is the electrochemical impedance spectroscopy of the composite solid electrolyte membrane prepared in Example 1 of the present invention. [Detailed Implementation]
[0037] The embodiments of the present invention will be described below with reference to the accompanying drawings and preferred embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are only for illustrating the present invention and not for limiting the scope of protection of the present invention.
[0038] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.
[0039] With the increasing demands for energy density and safety from electric vehicles, large-scale energy storage, and portable electronic devices, the thermal runaway risk posed by the flammable and leak-prone organic liquid electrolytes in traditional liquid batteries is becoming increasingly prominent, posing a key bottleneck to their further development. Solid-state electrolytes have attracted much attention due to their high safety, good mechanical strength, and excellent electrochemical stability, and have broad application prospects, especially in wearable devices, flexible electronics, and electric vehicles.
[0040] To date, successfully developed solid-state electrolytes include organic polymer electrolytes and inorganic oxide or sulfur compound electrolytes. Compared to inorganic electrolytes, polymer electrolytes offer better mechanical flexibility and lower manufacturing costs, which is beneficial for large-scale industrial production while further improving battery safety. However, the ionic conductivity and mechanical properties of polymer electrolytes are often difficult to balance, limiting their applications.
[0041] To achieve the above objectives, a first aspect of the present invention provides a method for preparing a solid electrolyte, comprising:
[0042] (1) Preparation of inorganic fillers;
[0043] (2) Preparation of organic polymer electrolyte solution;
[0044] (3) The inorganic filler is uniformly mixed in the organic polymer electrolyte solution by mechanical stirring to obtain a solid electrolyte precursor;
[0045] (4) The solid electrolyte precursor is shaped to obtain a solid electrolyte membrane.
[0046] Solid-state electrolyte systems mainly include inorganic and organic systems. Among inorganic systems, oxide electrolytes, sulfide electrolytes, and halide electrolytes are among the fastest-growing. Organic systems include polymer thin-film electrolytes such as polyethylene oxide and polyvinylidene fluoride. As one of the most widely studied solid-state electrolytes, oxide solid-state electrolytes, while possessing good ionic conductivity (10⁻⁶),... -4 ~10 -3 While lithium electrolytes exhibit high conductivity (S / cm), their high rigidity leads to poor contact with the electrode interface. Sulfide electrolytes possess the highest known conductivity among electrolytes, but their poor air stability (producing hydrogen sulfide upon contact with water) and high cost due to complex manufacturing processes limit their application in high-energy-density batteries. Halide electrolytes, while combining high ionic conductivity and low cost, suffer from compatibility issues with alkali metal anodes, impacting their application prospects in high-voltage and high-capacity batteries. Compared to inorganic systems, organic polymer electrolytes offer good mechanical flexibility and chemical stability, facilitating large-scale industrial production while further improving battery safety; however, their conductivity is relatively low. Among these, polyvinylidene fluoride (PVDF) solid electrolytes offer a more ideal electrochemical window and higher ionic conductivity compared to polyoxyethylene electrolytes, but residual N,N-dimethylformamide solvent during electrolyte membrane preparation can cause undesirable interfacial side reactions with lithium metal, severely restricting performance improvement. Introducing inorganic fillers is considered an effective strategy to enhance the ion-conducting capacity of electrolytes and regulate electrolyte-electrode interface affinity.
[0047] In view of the above characteristics, this application uses metal-doped mesoporous metal oxides as inorganic fillers. The dissociation of lithium salts is synergistically enhanced through the oxygen-vacancy oxide framework and the dipole interactions of polar atoms, thereby increasing the concentration of migratable lithium ions. Simultaneously, bonded N,N-dimethylformamide solvent molecules in the electrolyte system are absorbed by a large number of mesoporous structures, thus uniformly locked within the pores of the filler and acting as "ion transport bridges" to provide more transport channels for metal ions.
[0048] Therefore, in a specific implementation, iron-doped mesoporous tin dioxide (hereinafter referred to as "Fe-mSnO2") is taken as an example.
[0049] In some implementations, step (1) includes the following sub-steps:
[0050] Iron source, tin source, surfactant and nitrate are ground uniformly to obtain a powder precursor; and the powder precursor is heat-treated and then washed with water to remove impurities to obtain the inorganic filler.
[0051] In a specific implementation scheme, the iron source includes one or more of ferric sulfate, ferric nitrate, and ferric chloride; and / or, the tin source includes one or more of tin sulfate, tin nitrate, and tin chloride; and / or, the surfactant includes one or more of poloxamer, polyethylene glycol, polyethylene oxide, hexadecyltrimethylammonium bromide, and polyoxyethylene fatty alcohol ether; and / or, the nitrate includes one or more of lithium nitrate, potassium nitrate, and sodium nitrate.
[0052] In a specific implementation, the heat treatment step is carried out at 150 to 600°C for 5 to 12 hours.
[0053] In some implementations, step (2) includes the following sub-steps:
[0054] One or more alkali metal salts, such as lithium, sodium, or potassium salts, are dissolved in N,N-dimethylformamide to provide an alkali metal salt solution; an organic polymer is added to the alkali metal salt solution and heated to melt the organic polymer and obtain an organic polymer electrolyte solution.
[0055] In existing methods, considering the properties of the polymer, the organic polymer is generally dissolved in acetonitrile, N,N-dimethylformamide, dimethyl sulfoxide, or a mixed solvent of dimethyl sulfoxide with N,N-dimethylformamide, N,N-dimethylacetamide, and N-methylpyrrolidone to obtain a homogeneous organic polymer solution. However, because these solvents have high boiling points, they may be difficult to remove in subsequent drying steps, potentially leading to pores or interface defects in the resulting composite solid electrolyte, affecting the electrical and mechanical properties of the organic-inorganic composite solid electrolyte.
[0056] In view of the problems existing in the prior art, the inventors have discovered that by using mesoporous inorganic fillers, residual N,N-dimethylformamide solvent molecules can be absorbed and uniformly locked in the pore structure, thereby avoiding the presence of pores or interface defects in the obtained composite solid electrolyte and improving the electrical and mechanical properties of the obtained organic-inorganic composite solid electrolyte.
[0057] In a specific embodiment, the lithium salt includes one or more of lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium difluorooxalate borate, lithium di(oxalate borate), and lithium perchlorate; the sodium salt includes one or more of sodium bis(fluorosulfonyl)imide, sodium bis(trifluoromethanesulfonyl)imide, sodium difluorooxalate borate, sodium di(oxalate borate), and sodium perchlorate; the potassium salt includes one or more of potassium bis(fluorosulfonyl)imide, potassium bis(trifluoromethanesulfonyl)imide, potassium difluorooxalate borate, potassium di(oxalate borate), and potassium perchlorate; and / or, the organic polymer is selected from polyethylene oxide, polyvinylidene fluoride-hexafluoropropylene, polyvinyl difluoroethylene, or succinate.
[0058] In a specific embodiment, the organic polymer is selected from polyvinylidene fluoride-hexafluoropropylene. This organic polymer possesses excellent mechanical properties, is flexible and easily forms films, and effectively balances the trade-offs between electrical conductivity, mechanical properties, and interfacial stability. Furthermore, this organic polymer is readily soluble in N,N-dimethylformamide. Further, the molecular weight of the organic polymer is between 100 kM. w With 500km w By using organic polymers with high molecular weights to prepare organic polymer electrolyte solutions, subsequent crosslinking and polymerization steps are avoided, making the method of this application simpler and avoiding the application of complex equipment and complex process control.
[0059] In a preferred embodiment, the mass ratio of alkali metal salt to organic polymer is 1:(1-10).
[0060] In some embodiments, the magnetic stirring speed in step (3) is in the range of 500 to 1000 rpm, and / or the mechanical stirring time is 3 to 12 hours.
[0061] In a specific implementation plan, the mass ratio of inorganic filler to organic polymer is 1:(20-100).
[0062] In some implementations, step (4) includes placing the composite solid electrolyte precursor into a mold and then drying and shaping it.
[0063] In a specific implementation, the mold is configured as a polyetheretherketone mold to facilitate demolding; and / or, wherein the drying molding is carried out at 50 to 100°C for 6 to 15 hours.
[0064] Compared with existing preparation methods, the method of this application is simpler and more convenient, with a simple preparation process and low equipment requirements, making it suitable for large-scale preparation.
[0065] In a second aspect of the invention, a composite solid electrolyte prepared by the above method is provided, wherein the mass of the inorganic filler accounts for 1% to 20% of the mass of the composite solid electrolyte membrane.
[0066] The solid electrolyte membrane obtained by the method of this application has excellent flexibility, high ionic conductivity and mechanical strength, and combines the advantages of inorganic fillers and organic polymers. It can reduce polarization and side reactions during battery cycling and has high stability in battery cycling operation.
[0067] Furthermore, in a third aspect of the present invention, a solid-state lithium battery is provided as an example, comprising: a positive electrode made of lithium iron phosphate; and a negative electrode made of lithium.
[0068] An organic-inorganic solid electrolyte membrane, wherein the composite solid electrolyte membrane is located between the positive and negative electrodes and is made of a solid electrolyte prepared by the above method or a solid electrolyte as described above.
[0069] Compared with the prior art, the solid alkali metal battery assembled with the flexible solid electrolyte membrane of the present invention exhibits excellent rate performance, with high capacity and slow decay at high rates.
[0070] The present invention will be further described below with reference to specific embodiments, but the embodiments do not limit the present invention in any way. Unless otherwise stated, the raw materials and reagents used in the embodiments of the present invention are conventionally purchased raw materials and reagents.
[0071] Example 1
[0072] Weigh 0.4g poloxamer (purchased from Aladdin), 0.4g tin sulfate tetrahydrate (purchased from Aladdin), and 0.013g ferric sulfate hexahydrate (purchased from Aladdin) into a mortar and grind for 3-5 minutes. Then add 0.58g potassium nitrate (purchased from Aladdin) and 0.3g lithium nitrate (purchased from Aladdin) in sequence, grind thoroughly, and then heat treat at 160℃ and 400℃ for 3 hours in sequence to form brown Ni-mCeO2 inorganic filler powder. 0.5 g of lithium difluorosulfonylimide (purchased from Duoduo Reagent) was dissolved in 7.5 mL of N,N-dimethylformamide (purchased from Aladdin), and the solution was magnetically stirred at 500 rpm for 0.5 hours until the lithium difluorosulfonylimide was completely dissolved. Then, 1 g of polyvinylidene fluoride-hexafluoropropylene (purchased from Aladdin, molecular weight 400,000) was added, and the solution was heated to 80°C and stirred for 2 hours until the polyvinylidene fluoride-hexafluoropropylene was completely dissolved. After mixing evenly, an organic polymer electrolyte solution was formed. 0.03 g of Fe-mSnO2 inorganic filler powder was added to the above organic polymer electrolyte solution, and the mixture was stirred for 6 hours until the slurry was evenly mixed. Then, the mixture was placed in a polyetheretherketone mold (purchased from Kelude) with a diameter of 19 mm and dried at 60°C for 12 hours to obtain a solid electrolyte membrane with a thickness of 65 μm.
[0073] The composite solid electrolyte membrane of Example 1 is made of the following components: containing Fe-mSnO2 inorganic filler and organic polymer solid electrolyte (polyvinylidene fluoride-hexafluoropropylene and lithium bisfluorosulfonylimide, in a mass ratio of 2:1); the inorganic filler accounts for 8% of the mass of the solid electrolyte membrane; the thickness of the solid electrolyte membrane is 65 μm.
[0074] Example 2
[0075] The preparation method in this embodiment is the same as that in Example 1, except that lithium bis(fluorosulfonyl)imide in the organic polymer solution is replaced with lithium bis(trifluoromethanesulfonate)imide (purchased from Duoduo Reagent).
[0076] The composite solid electrolyte membrane of Example 2 is made of the following components: containing Fe-mSnO2 inorganic filler and organic polymer solid electrolyte (polyvinylidene fluoride-hexafluoropropylene and lithium bis(trifluoromethanesulfonate) imine, in a mass ratio of 2:1); the inorganic filler accounts for 10% of the mass of the solid electrolyte membrane; the thickness of the solid electrolyte membrane is 65 μm.
[0077] Example 3
[0078] The preparation method in this embodiment is the same as in Example 1, except that the mass ratio of Fe-mSnO2 inorganic filler to solid film mass is adjusted to 5%.
[0079] The composite solid electrolyte membrane of Example 3 is made of the following components: containing Fe-mSnO2 inorganic filler and organic polymer solid electrolyte (polyvinylidene fluoride-hexafluoropropylene and lithium bisfluorosulfonyl imide in a mass ratio of 2:1); the inorganic filler accounts for 5% of the mass of the composite solid electrolyte membrane; the thickness of the composite solid electrolyte membrane is 65 μm.
[0080] Example 4
[0081] The preparation method in this embodiment is the same as in Example 1, except that the mass ratio of Fe-mSnO2 inorganic filler to the mass of the solid film is adjusted to 12%.
[0082] The composite solid electrolyte membrane of Example 4 is made of the following components: containing Fe-mSnO2 inorganic filler and organic polymer solid electrolyte (polyvinylidene fluoride-hexafluoropropylene and lithium bisfluorosulfonylimide, in a mass ratio of 2:1); the inorganic filler accounts for 12% of the mass of the composite solid electrolyte membrane; the thickness of the solid electrolyte membrane is 65 μm.
[0083] Test Example 1
[0084] The solid electrolyte membrane obtained in the example was photographed to obtain images of its flatness and thickness.
[0085] Test Example 2
[0086] The inorganic Fe-mSnO2 filler obtained in the examples was photographed using a scanning electron microscope (Sigma360, purchased from ZEISS) at a magnification of 350,000 to obtain scanning electron microscope images of the Fe-mSnO2 material.
[0087] Test Example 3
[0088] The composite solid electrolyte membrane from the examples was assembled into a lithium-stainless steel half-cell, and linear sweep voltammetry was performed on an electrochemical workstation (purchased from Shanghai Chenhua, model CHI760E) with a test voltage of 0-6V. This linear sweep voltammetry test was conducted according to the national standard GB / T 38894-2020. The test results are as follows... Figure 4 As shown.
[0089] Test Example 4
[0090] The composite solid electrolyte membrane from the examples was assembled into a stainless steel sheet symmetrical battery. Electrochemical impedance spectroscopy (EIS) was performed at 25°C using an electrochemical workstation. The EIS was performed according to the national standard GB / T39482, with an AC amplitude of 10mV and a frequency of 100kHz–0.1Hz. The test results are as follows: Figure 5 As shown.
[0091] Test Example 5
[0092] The solid electrolyte membrane described in this embodiment was assembled into an alkali metal battery to verify its performance in a full cell. Specifically, in this embodiment, the alkali metal battery is a solid lithium metal battery with a positive electrode made of lithium iron phosphate and a negative electrode made of lithium. The rate performance of this battery was tested at 0.5C, 1C, 2C, 3C, and 5C, and the test results are shown in Table 1. The rate performance test of this battery was conducted according to the national standard GB / T 36276.
[0093] Table 1
[0094]
[0095] [Explanation of Test Results]
[0096] Figure 1 The microstructure of Fe-mSnO2 inorganic filler is shown, with particle diameters of approximately 40–70 nm.
[0097] Depend on Figure 2 It can be seen that the solid electrolyte membrane presents a circular thin film shape when laid flat, and the surface is relatively uniform.
[0098] Depend on Figure 3 It can be seen that the solid electrolyte has a thickness of 65μm and good mechanical properties, which can meet the actual application requirements.
[0099] Figure 4 The electrochemical window obtained by linear sweep voltammetry is shown, which is stable at 4.8 V, indicating that the solid electrolyte membrane exhibits a good electrochemical operating window.
[0100] Figure 5The test results show that the ionic conductivity of the solid electrolyte membrane in Example 1 is 1.58 × 10⁻⁶ at room temperature (25°C). -3 The S / cm indicates a high ionic conductivity. This demonstrates that the flexible composite solid electrolyte membrane in Example 1 can combine the high ionic conductivity of inorganic fillers with the mechanical properties of organic polymer electrolytes.
[0101] The data in Table 1 show that the discharge capacities at current densities of 0.5C, 1C, 2C, 3C, and 5C are 150.3 mAh / g, 141.7 mAh / g, 129.8 mAh / g, 115.8 mAh / g, and 94.5 mAh / g, respectively. This indicates that the composite solid electrolyte membrane prepared by the method of this application has excellent rate discharge capability.
[0102] The ionic conductivity of Examples 1 and 2 were 0.32 × 10⁻⁶, respectively. -3 S / cm and 0.21×10 -3 The S / cm value demonstrates that changes in lithium salt have little effect on the ionic conductivity of the solid electrolyte membrane.
[0103] The ionic conductivity of Examples 1, 3, and 4 is 0.32 × 10⁻⁶. -3 S / cm, 0.12×10 -3 S / cm and 0.10×10 -3 The S / cm ratio indicates that increasing the mass fraction of inorganic filler can improve the ionic conductivity of the flexible composite solid electrolyte membrane, but the reduction in organic solid electrolyte components leads to a significant decrease in mechanical properties. The inventors have discovered that when the mass of inorganic filler accounts for 1 to 20% of the composite solid electrolyte membrane's mass, the influence between ionic conductivity and mechanical properties can be balanced; within this range, mechanical properties can be maintained while preserving high ionic conductivity. Therefore, the rational configuration of inorganic and organic components is of great significance.
[0104] The above embodiments are merely preferred embodiments provided to fully illustrate the present invention, and the scope of protection of the present invention is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on the present invention are all within the scope of protection of the present invention.
Claims
1. A method for preparing a solid-state electrolyte, characterized by, The method comprises: (1) preparing an inorganic filler; (2) preparing an organic polymer electrolyte solution; (3) uniformly mixing the inorganic filler in the organic polymer electrolyte solution by mechanical stirring to obtain a solid-state electrolyte precursor; (4) forming the solid-state electrolyte precursor to obtain a solid-state electrolyte membrane.
2. The inorganic filler is a metal-doped mesoporous metal oxide, and the doping amount of the metal is 1-10%.
3. The method of claim 2, wherein, Step (1) comprises the following sub-steps: Grinding the metal A doping source, metal B source, surfactant and nitrate uniformly to obtain a powder precursor; and performing heat treatment on the powder precursor and then washing with water to remove impurities to obtain the inorganic filler.
4. The method of claim 3, wherein, The types of doped metal elements include one or more of iron, cobalt, nickel, copper, titanium and chromium, and the raw materials include one or more of metal sulfate, metal nitrate and metal chloride; the metal oxides include one or more of cerium oxide, tin oxide and manganese oxide, and the raw materials include one or more of metal sulfate, nitrate and chloride; the surfactants include one or more of poloxamer, polyethylene glycol, polyethylene oxide, cetyltrimethylammonium bromide and polyoxyethylene fatty alcohol ether; the nitrates include one or more of lithium nitrate, potassium nitrate and sodium nitrate; and the heat treatment step is performed at 150-600°C for 5-12 hours.
5. The method of claim 1, wherein, Step (2) comprises the following sub-steps: Dissolving one or more of alkali metal salts such as lithium salt, sodium salt or potassium salt in N,N-dimethylformamide to provide an alkali metal salt solution; adding an organic polymer to the alkali metal salt solution and heating to melt the organic polymer and obtain an organic polymer electrolyte solution.
6. The method of claim 5, wherein, The lithium salt includes one or more of lithium bisfluorosulfonylimide, lithium bis(trifluoromethanesulfonyl)imide, lithium difluoro(oxalato)borate, lithium bis(oxalato)borate and lithium perchlorate; the sodium salt includes one or more of sodium bisfluorosulfonylimide, sodium bis(trifluoromethanesulfonyl)imide, sodium difluoro(oxalato)borate, sodium bis(oxalato)borate and sodium perchlorate; the potassium salt includes one or more of potassium bisfluorosulfonylimide, potassium bis(trifluoromethanesulfonyl)imide, potassium difluoro(oxalato)borate, potassium bis(oxalato)borate and potassium perchlorate; and / or, the organic polymer is selected from polyethylene oxide, polyvinylidene fluoride-hexafluoropropylene, polydifluoroethylene or succinonitrile; and / or, the mass ratio of the alkali metal salt to the organic polymer is 1:(1-10).
7. The method of claim 1, wherein, In step (3), the stirring speed of magnetic stirring is in the range of 500-1000 revolutions per minute, and the stirring time is 3-12 hours, wherein the mass ratio of the inorganic filler to the organic polymer is 1:(20-100).
8. The method of claim 1, wherein, Step (4) comprises: placing the composite solid-state electrolyte precursor into a mold and then performing dry forming; wherein the dry forming is performed at 50-100°C for 6-15 hours.
9. A solid state electrolyte membrane, characterized by, The solid-state electrolyte membrane is made of the solid-state electrolyte prepared by the method of any one of claims 1-8, wherein the mass of the inorganic filler accounts for 1-20% of the mass of the solid-state electrolyte membrane.
10. Use of a solid-state electrolyte membrane in an alkali metal battery, characterized in that: When the solid electrolyte membrane is used in a full cell of an alkali metal battery, the solid electrolyte membrane is located between a positive electrode and an alkali metal negative electrode and is made of a solid electrolyte prepared by the method of any one of claims 1 to 8 or is a solid electrolyte membrane as claimed in claim 9.