Electrolyte membrane and preparation method thereof
The preparation of inorganic nanowire/3D crimped polymer fiber composite solid electrolyte membranes by electrospinning technology solves the problem of discontinuous ion conduction paths between inorganic nanowires and organic fiber membranes, improves the ionic conductivity, electrochemical window and mechanical strength of lithium-ion batteries, extends the cycle life of batteries, and enhances battery safety and energy density.
Patent Information
- Application Number
- CN202410581245.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-11
- Publication Date
- 2025-11-11
AI Technical Summary
The discontinuity of the ion conduction path between inorganic nanowires and organic fiber membranes leads to uneven ion conduction and insufficient mechanical properties in lithium batteries, affecting battery safety and cycle performance.
3D crimped polymer fiber membranes were prepared using electrospinning technology and then composited with pre-oxidized inorganic nanowires to form an inorganic nanowire/3D crimped polymer fiber composite solid electrolyte membrane. Continuous ion transport channels were constructed by permeating ceramic nanowires into the polymer membrane.
It improves the ionic conductivity, electrochemical window, and mechanical strength of lithium-ion batteries, inhibits lithium dendrite growth, extends battery cycle life, and enhances battery safety and energy density.
Smart Images
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of solid-state batteries, specifically relating to an electrolyte membrane and its preparation method. Background Technology
[0002] With the increasing demand from mobile devices, smart grids, and electric vehicles, higher requirements are being placed on the safety and stability of lithium-ion batteries. However, traditional organic liquid electrolytes contain flammable and volatile solvents, resulting in insufficient stability and safety issues. The instability of organic liquid electrolytes hinders lithium-ion batteries from achieving higher energy density, longer operating life, and safer performance. Compared to organic liquid electrolytes, using solid electrolytes not only improves the long-term thermal and electrochemical stability of batteries but also eliminates the need for a separator and increases energy density. For these reasons, solid electrolytes are considered a potential alternative for improving the cycle performance of lithium-ion batteries. Therefore, the development of next-generation lithium-ion batteries—solid-state batteries—with higher energy density and safety performance has received increasing attention.
[0003] Inorganic solid electrolytes (ISEs), including oxide electrolytes and sulfide electrolytes, possess excellent ionic conductivity and a wide electrochemical window. Polymer solid electrolytes (SPEs) offer significant advantages over ISEs, such as ease of processing, low cost, and good electrode contact, which helps mitigate the large volume expansion of the electrode. Therefore, composite solid electrolytes (CSEs) successfully combine the advantages of ISEs and SPEs, maintaining good electrochemical performance while retaining certain mechanical properties. However, the large amount of particulate inorganic ceramic filler is prone to agglomeration and clumping, resulting in highly uneven crystalline polymers in different regions of the CSE. As a possible solution, one-dimensional inorganic nanowire materials can effectively alleviate agglomeration. However, the abundant distribution of amorphous phases and dense pores in the polymer electrolyte membrane hinders the penetration of ceramic nanowires into the polymer substrate, easily leading to discontinuities in the ion conduction pathway between the nanowires and the polymer phase.
[0004] Therefore, developing a solid electrolyte membrane that can overcome the above-mentioned defects is of great practical significance. Summary of the Invention
[0005] To overcome the technical problem of discontinuous ion conduction pathways between existing inorganic nanowire and organic fiber membranes, this invention provides a solid electrolyte membrane composed of inorganic nanowires and 3D coiled polymer fibers, along with its preparation method. This solid electrolyte membrane effectively promotes the permeability of ceramic nanowires throughout the polymer electrolyte, providing a long-distance and continuous transport channel for lithium ions at the one-dimensional nanowire-polymer interface.
[0006] An organic-inorganic composite solid electrolyte membrane comprises a 3D coiled polymer fiber membrane and an inorganic nanowire; its preparation method includes the following steps:
[0007] 1. Electrospinning was performed using sulfonated polymer solution and lithium salt-containing polyethylene oxide solution as spinning solution to obtain 3D crimped polymer fiber membranes.
[0008] 2. Mix organic matter, cobalt salt, lanthanum salt and organic solvent to obtain organic spinning solution; spin the organic spinning solution and then sinter the resulting fiber membrane at high temperature to obtain pre-oxidized inorganic nanowires;
[0009] 3. The pre-oxidized inorganic nanowires, polymer, lithium salt and organic solvent are mixed to obtain a mixed solution; then the mixed solution is coated on the surface of the 3D rolled polymer fiber membrane and dried to obtain an organic-inorganic composite solid electrolyte membrane.
[0010] A more detailed preparation method includes the following steps:
[0011] I. Preparation of 3D Curled Polymer Fiber Membranes
[0012] (1) Dissolve the sulfonated polymer in an organic solvent to obtain a spinning solution of the sulfonated polymer;
[0013] (2) Dissolve polyethylene oxide and lithium salt in an organic solvent to obtain a spinning solution of polyethylene oxide;
[0014] (3) The two spinning solutions prepared above are transferred to two pipettes on a parallel needle for electrospinning. After electrospinning, the resulting polymer film is dried to obtain a 3D curled polymer fiber film.
[0015] The steps (1) and (2) above are not in any particular order;
[0016] II. Preparation of Pre-oxidized Inorganic Nanowires
[0017] (4) Dissolve the organic matter in an organic solvent, then add cobalt salt and lanthanum salt to it, stir and mix to obtain an organic spinning solution; the organic matter is selected from at least one of the following: polyethylene oxide, polyvinyl alcohol, N-methylpyrrolidone;
[0018] (5) The organic spinning solution obtained in step (4) is spun using the dual effects of high-speed airflow and electrostatic attraction;
[0019] (6) After spinning, the resulting fiber membrane is dried; then the dried fiber membrane is sintered at high temperature to obtain pre-oxidized inorganic nanowires.
[0020] III. Preparation of Organic-Inorganic Composite Solid Electrolyte Membranes
[0021] (7) Dissolve the pre-oxidized inorganic nanowires prepared in step (6) in an organic solvent, then add polymer and lithium salt to it, stir and mix to obtain a mixed solution;
[0022] (8) The mixed solution described in step (7) is coated on the surface of the 3D curled polymer fiber membrane, and the residual solvent is removed by drying to obtain a solid electrolyte membrane composed of inorganic nanowires / 3D curled polymer fibers.
[0023] In step (1) of the above method, the sulfonated polymer may be selected from at least one of the following: sulfonated polysulfone (SPSU), sulfonated polyether sulfone (SPESU), or sulfonated polyphenylene sulfone (SPPSU); the weight-average molecular weight of the sulfonated polymer may be 30,000-80,000.
[0024] In step (1) of the above method, the organic solvent is selected from at least one of the following: dimethylformamide (DMF), dimethyl sulfoxide (DMSO), and acetone (AC).
[0025] In step (1) of the above method, the ratio of sulfonated polymer to organic solvent in the spinning solution of the sulfonated polymer is 1.5g:5mL.
[0026] The sulfonated polymer used in step (1) of the above method can be obtained commercially or can be prepared by sulfonating an unsulfonated polymer.
[0027] The specific sulfonation method is as follows: After mixing the polymer to be sulfonated with the sulfonating agent, the sulfonation treatment is carried out. After the treatment is completed, the polymer is transferred to distilled water for immersion until it reaches neutrality, dried, and the residual solvent is removed to obtain the sulfonated polymer.
[0028] The polymer to be sulfonated may be selected from at least one of the following: polysulfone (PSU), polyethersulfone (PESU), or polyphenylene sulfone (PPSU);
[0029] The sulfonating agent may be selected from any one of the following: concentrated sulfuric acid, sulfur trioxide, or chlorosulfonic acid;
[0030] The sulfonation treatment conditions are as follows: stirring in a water bath at 60°C for 4 hours.
[0031] In step (2) of the above method, the weight-average molecular weight of the polyethylene oxide (PEO) can be Mw100,000 to Mw800,000;
[0032] In step (2) of the above method, the lithium salt can be one of lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(oxalateborate)borate (LiBOB), and lithium difluorooxalateborate (LiDFOB);
[0033] In step (2) of the above method, the organic solvent is selected from at least one of the following: acetonitrile, dimethylformamide (DMF), anisole, and chloroform (TM);
[0034] In step (2) of the above method, the mass ratio of the polyethylene oxide (PEO) to the lithium salt is (1-5):1;
[0035] In step (2) of the above method, the mass concentration of polyethylene oxide in the polyethylene oxide spinning solution is 10-15%.
[0036] In step (3) of the above method, the electrospinning conditions are as follows: the needle diameter corresponding to the sulfonated polymer spinning solution is 0.1-0.5 mm, the extrusion rate of the sulfonated polymer spinning solution is set to 0.1-1 mL / h, the needle diameter corresponding to the polyethylene oxide spinning solution is 0.1-0.5 mm, the extrusion rate of the polyethylene oxide spinning solution is set to 0.1-1 mL / h, the receiver rotation speed is 60 rpm / min, the distance between the needle and the rotating receiver is 0.1-1 m, the spinning voltage is 30 kV, the spinning temperature is 200 ℃, and the spinning time is 1-10 h.
[0037] According to one embodiment of the present invention, the electrospinning conditions in step (3) are as follows: the needle diameter corresponding to the sulfonated polymer spinning solution is 0.15 mm, the needle diameter corresponding to the polyethylene oxide spinning solution is 0.1 mm, the extrusion rates of the sulfonated polysulfone spinning solution and the polyethylene oxide spinning solution are set to 0.1 mL / h and 0.3 mL / h, respectively, the receiving distance is 10 cm, and electrospinning is performed for 10 hours at a temperature of 200 °C.
[0038] According to another embodiment of the present invention, the electrospinning conditions in step (3) are as follows: the needle diameter corresponding to the sulfonated polymer spinning solution is 0.1 mm, the needle diameter corresponding to the polyethylene oxide spinning solution is 0.1 mm, the extrusion rates of the sulfonated polyethersulfone spinning solution and the polyvinyl alcohol spinning solution are set to 0.3 mL / h and 0.5 mL / h, respectively, the receiving distance is 15 cm, and electrospinning is performed at a temperature of 200 °C for 6 hours.
[0039] According to another embodiment of the present invention, the electrospinning conditions in step (3) are as follows: the needle diameter corresponding to the sulfonated polyphenylene sulfone spinning solution is 0.2 mm, the needle diameter corresponding to the polyoxyethylene spinning solution is 0.1 mm, the extrusion rates of the sulfonated polyphenylene sulfone spinning solution and the polyoxyethylene spinning solution are set to 0.5 mL / h and 0.7 mL / h respectively, the receiving distance is 20 cm, and electrospinning is performed for 8 hours at a temperature of 200 °C.
[0040] According to another embodiment of the present invention, the electrospinning conditions in step (3) are as follows: the needle diameter corresponding to the sulfonated polymer spinning solution is 0.1 mm, the needle diameter corresponding to the polyethylene oxide spinning solution 1 is 0.1 mm, the extrusion rates of the sulfonated polyethersulfone spinning solution and the polyethylene oxide spinning solution are set to 0.6 mL / h and 0.9 mL / h respectively, the receiving distance is 20 cm, and electrospinning is performed.
[0041] In step (3) of the above method, the thickness of the 3D rolled polymer fiber membrane can be 10μm-20μm.
[0042] In step (4) of the above method, the weight-average molecular weight of the polyethylene oxide (PEO) can be Mw100,000 to Mw800,000; and the weight-average molecular weight of the polyvinyl alcohol (PVA) can be Mw100,000 to Mw800,000.
[0043] In step (4) of the above method, the organic solvent is selected from at least one of the following: dimethylformamide (DMF), dimethyl sulfoxide (DMSO), and acetone (AC);
[0044] In step (4) of the above method, the cobalt salt may be selected from at least one of the following: cobalt acetate, cobalt nitrate, cobalt carbonate, cobalt sulfate, cobalt fluoride, cobalt chloride, cobalt bromide, and cobalt iodide;
[0045] In step (4) of the above method, the lanthanum salt may be selected from at least one of the following: lanthanum acetate, lanthanum nitrate, lanthanum chloride, and lanthanum carbonate;
[0046] In step (4) of the above method, the mass ratio of the organic matter, cobalt salt, and lanthanum salt is 1.5:(0.1-0.3):(0.15-0.3);
[0047] In step (4) of the above method, the mass concentration of organic matter in the organic spinning solution 2 is 5-20%.
[0048] In step (5) of the above method, the spinning conditions are as follows: the needle diameter is 0.1-1 mm, the extrusion rate of the spinning solution is set to 0.1-1 ml / h, the receiver rotation speed is 60 rpm, the distance between the needle and the collector is 0.1-1 m, the spinning is carried out under a voltage of 30-50 kV and an air pressure of 0.1-10 MPa (such as 0.1 MPa, 0.2 MPa, 0.3 MPa), the spinning temperature is 150-250℃, and the spinning time is 1-10 h.
[0049] In step (6) of the above method, the high-temperature sintering is carried out in a muffle furnace; the conditions for the high-temperature sintering are: heating to 850-950℃ at a temperature rate of 0.5-2℃ / min and holding for sintering for 2 hours.
[0050] In step (7) of the above method, the organic solvent is selected from at least one of the following: acetonitrile, dimethylformamide (DMF), anisole, and chloroform (TM);
[0051] In step (7) of the above method, the polymer is selected from at least one of the following: polyethylene oxide (PEO, Mw 100,000 to 800,000) and polyvinyl alcohol (PVA, Mw 100,000 to 800,000);
[0052] In step (7) of the above method, the lithium salt can be one of lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(oxalateborate)borate (LiBOB), and lithium difluorooxalateborate (LiDFOB);
[0053] In step (7) of the above method, the mass ratio of the pre-oxidized inorganic nanowire, the polymer, and the lithium salt is (10-15):(10-15):(1-1.5), and can be further 10:(10-15):(1-1.5), specifically 10:11:1, 10:10:1, or 10:15:1.
[0054] In step (7) of the above method, the mass concentration of the pre-oxidized inorganic nanowires in the mixture is 10-20%wt.
[0055] In step (8) of the above method, the mass ratio of the mixed solution (m1) to the 3D coiled polymer fiber membrane (m2) is 10-20% (m1:m2).
[0056] The organic-inorganic composite solid electrolyte membrane prepared by the above method is also within the scope of protection of this invention.
[0057] This invention also protects the application of the above-mentioned organic-inorganic composite solid electrolyte membrane.
[0058] The application of the organic-inorganic composite solid electrolyte membrane provided by this invention is its application in the preparation of lithium-ion batteries.
[0059] The present invention also provides a lithium-ion solid-state battery.
[0060] The lithium-ion solid-state battery provided by the present invention includes a positive electrode, a negative electrode, and an organic-inorganic composite solid electrolyte membrane provided by the present invention.
[0061] Compared with the prior art, the present invention has the following beneficial technical effects:
[0062] 1. This invention employs an electrospinning process to form inorganic ceramic nanowires coated with 3D crimped polymer fibers, which enables the composite solid electrolyte membrane to possess high ionic conductivity at room temperature. Figure 1), and a wider electrochemical window ( Figure 2 Meanwhile, the high mechanical strength of this structure effectively suppresses lithium dendrite growth, greatly improving cycle performance. Figure 3 );
[0063] 2. The inorganic nanowire / 3D coiled polymer fiber composite solid electrolyte membrane prepared by this invention reduces the crystallinity of the polymer by adding inorganic nanowire fillers, and forms a 3D fiber skeleton with a fluffy, large-pore, and high-porosity structure. Figure 4 );
[0064] 3. The inorganic nanowire / 3D coiled polymer fiber composite solid electrolyte membrane prepared by the present invention utilizes the oxygen vacancies and Lewis acid sites on the surface of ceramic nanowires to promote the dissociation / complexation of lithium salts, and constructs a highly efficient ion transport network with the help of 3D coiled fibers and one-dimensional inorganic nanowires.
[0065] 4. The inorganic nanowire / 3D curled polymer fiber composite solid electrolyte membrane prepared by the present invention can enhance the permeability of inorganic ceramic nanowires in the fiber membrane and improve the continuity of nanowires.
[0066] This invention utilizes electrospinning technology to prepare an inorganic ceramic nanowire / 3D coiled polymer fiber composite solid electrolyte membrane. The 3D coiled polymer fiber film possesses a large-pore structure with a porosity reaching 90%, allowing the ceramic nanowires to more easily penetrate into the 3D coiled polymer fiber membrane without being blocked by the polymer fibers. This effectively improves the permeability of the nanowires in the fiber membrane. The formed 3D continuous polymer-nanowire transport channels provide a more efficient conduction path for ion transport. This ensures that the final composite solid electrolyte membrane exhibits both excellent electrochemical performance and outstanding mechanical properties. The composite solid electrolyte membrane prepared by this invention exhibits a 10-1℃ at room temperature. -4 The high ionic conductivity (S / cm) and wide electrochemical window (over 4.1V), along with mechanical properties reaching 7MPa, indicate that this electrolyte membrane can effectively suppress lithium dendrite growth, achieving a cycle life exceeding 500 hours. Therefore, lithium-ion solid-state batteries constructed from this composite solid-state electrolyte membrane possess characteristics of high ionic conductivity, high safety, and long cycle life. Attached Figure Description
[0067] Figure 1 Electrochemical impedance spectroscopy (EIS) of Li|Li coin cells assembled using the inorganic nanowire / 3D coiled polymer fiber composite solid electrolyte membrane prepared in Example 1;
[0068] Figure 2LSV data of Li|Li coin cells assembled using the inorganic nanowire / 3D coiled polymer fiber composite solid electrolyte membrane prepared in Example 1;
[0069] Figure 3 The cycling data are for Li|Li coin cells assembled using the inorganic nanowire / 3D coiled polymer fiber composite solid electrolyte membrane prepared in Example 1.
[0070] Figure 4 The image shows the cross-sectional morphology of the solid electrolyte membrane composed of inorganic nanowires / 3D coiled polymer fibers prepared in Example 1. Detailed Implementation
[0071] The present invention will now be described in further detail with reference to specific embodiments. The given embodiments are merely illustrative of the invention and not intended to limit its scope. The embodiments provided below can serve as a guide for further improvements by those skilled in the art and do not constitute a limitation on the invention in any way.
[0072] Unless otherwise specified, the experimental methods used in the following examples are conventional methods, performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Unless otherwise specified, the materials and reagents used in the following examples are commercially available.
[0073] Example 1: Preparation of Organic-Inorganic Composite Solid Electrolyte Membrane
[0074] I. Preparation of 3D curled polymer fiber membranes
[0075] 1. Add 1.5 g of polysulfone (molecular weight Mw 30,000) to 10 mL of concentrated sulfuric acid (mass fraction 98%) and stir in a water bath at 60 °C for 4 h for sulfonation treatment. Then, transfer the treated polysulfone to distilled water and soak for 24 h to reach neutrality. After drying in an oven at 50 °C to remove residual solvent, sulfonated polysulfone (Mw 30,000) is prepared.
[0076] 2. Add 1.5g of sulfonated polysulfone prepared in step 1 to 5mL of dimethylformamide and stir magnetically for 4h to obtain a spinning solution of sulfonated polysulfone;
[0077] 3. Mix 1g of polyoxyethylene (Mw 400,000) with 0.2g of LiFSI and add it to 9mL of acetonitrile. Stir continuously for 3h to prepare a spinning solution of polyoxyethylene.
[0078] 4. Transfer the two spinning solutions prepared above to two pipettes on a parallel needle, and draw the spinning solutions under a voltage of 30kV in a high-voltage electrospinning machine; the needle diameter corresponding to the sulfonated polymer spinning solution is 0.15mm, the needle diameter corresponding to the polyethylene oxide spinning solution is 0.1mm, the extrusion rate of the sulfonated polysulfone spinning solution (1mL) and the polyethylene oxide spinning solution (1mL) is set to 0.1mL / h and 0.3mL / h, respectively, the receiving distance is 10cm, and electrospinning is carried out at a temperature of 200℃ for 10 hours;
[0079] 5. Remove the electrospun polymer film from the rotary receiver and dry it in an oven at 50°C to remove residual solvent, so as to prepare a 3D rolled polymer fiber film (10 μm thick).
[0080] II. Preparation of Pre-oxidized Inorganic Nanowires
[0081] 6. Add 1.5g of N-methylpyrrolidone to 10mL of dimethylformamide and stir for 15min; then add cobalt nitrate (0.10g) and lanthanum nitrate (0.15g) in sequence, and stir again for 4h to obtain N-methylpyrrolidone spinning solution;
[0082] 7. Transfer the spinning solution (1 mL) obtained in step 6 into the needle tube of the spinning machine (d = 1.0 mm). Under an electrostatic voltage of 40 kV and an air pressure of 0.1 MPa, spinning is carried out using the combined effects of high-speed airflow and electrostatic attraction. The extrusion rate of the N-methylpyrrolidone spinning solution is 0.1 mL / h, the receiving distance between the needle head and the collector is 10 cm, the spinning temperature is 200 °C, and the spinning time is 10 hours.
[0083] 8. Remove the fiber membrane from the collector and transfer it to a vacuum oven at 50°C to dry for 24 hours; then place the dried thin fiber membrane into a muffle furnace and heat it to 900°C at a temperature rate of 2°C / min, and sinter it in an air atmosphere at 900°C for 2 hours to prepare pre-oxidized inorganic nanowires.
[0084] III. Preparation of solid electrolyte membranes composed of inorganic nanowires / 3D coiled polymer fibers
[0085] 9. Dissolve 1g of pre-oxidized inorganic nanowires prepared in step 8 in 9mL of acetonitrile, then add polyethylene oxide (Mw 400,000) (1.1g) and LiFSI (0.1g) to the solution, and stir again for 24h.
[0086] 10. Pour the mixed solution prepared in step 9 into the 15cm×20cm×10μm 3D coiled polymer fiber membrane prepared in step 5, and dry it in a vacuum oven for 48h to remove residual solvent, to obtain an inorganic nanowire / 3D coiled polymer fiber composite solid electrolyte membrane (thickness 30μm).
[0087] Example 2: Preparation of Organic-Inorganic Composite Solid Electrolyte Membrane
[0088] I. Preparation of 3D curled polymer fiber membranes
[0089] 1. Mix 1.0 g of polyethersulfone (molecular weight Mw 50,000) with 10 g of sulfur trioxide and stir in a water bath at 60 °C for 4 h for sulfonation treatment. Then, transfer the treated polyethersulfone to distilled water and soak it for 24 h to make it neutral. Finally, dry it in an oven at 50 °C to remove residual solvent to prepare sulfonated polyethersulfone (Mw 50,000).
[0090] 2. Add 1.0 g of sulfonated polyethersulfone prepared in step 1 to 9.5 mL of dimethylformamide and stir magnetically for 4 h to obtain the spinning solution of sulfonated polyethersulfone;
[0091] 3. Mix 1.5g of polyethylene oxide Mw 300,000 with 0.1g of LiFSI and add it to 9.5mL of acetonitrile. Stir continuously for 3h to prepare a spinning solution of polyvinyl alcohol.
[0092] 4. Transfer the two spinning solutions prepared above to two pipettes on parallel needles respectively, and draw the spinning solutions under a voltage of 30kV in a high-voltage electrospinning machine; the needle diameter corresponding to the sulfonated polymer spinning solution is 0.1mm, the needle diameter corresponding to the polyethylene oxide spinning solution is 0.1mm, the extrusion rate of the sulfonated polyethersulfone spinning solution (1mL) and the polyethylene oxide spinning solution (1.5mL) is set to 0.3mL / h and 0.5mL / h respectively, the receiving distance is 15cm, and electrospinning is carried out at a temperature of 200℃ for 6 hours;
[0093] 5. Remove the electrospun polymer membrane from the collector and dry it in a 50°C oven to remove residual solvent, so as to prepare a 3D rolled polymer fiber membrane (20μm thick).
[0094] II. Preparation of Pre-oxidized Inorganic Nanowires
[0095] 6. Add 1g of N-methylpyrrolidone to 10mL of dimethylformamide and stir for 15min; then add cobalt nitrate (0.15g) and lanthanum nitrate (0.15g) in sequence, and stir again for 4h to obtain N-methylpyrrolidone spinning solution;
[0096] 7. Transfer the spinning solution (1 mL) obtained in step 6 into the needle tube of the spinning machine (d = 0.1 mm). Under an electrostatic voltage of 40 kV and an air pressure of 0.2 MPa, spinning is carried out using the combined effects of high-speed airflow and electrostatic attraction. The extrusion rate of the polyvinylpyrrolidone spinning solution is 0.1 mL / h, the distance between the needle head and the collector is 40 cm, the spinning temperature is 200 °C, and the spinning time is 10 hours.
[0097] 8. Remove the fiber membrane from the collector and transfer it to a vacuum oven at 50°C to dry for 24 hours. Then, place the dried thin fiber membrane into a muffle furnace and heat it to 950°C at a temperature rate of 1°C / min. Finally, sinter it in an air atmosphere at 950°C for 2 hours to prepare pre-oxidized inorganic nanowires.
[0098] III. Preparation of solid electrolyte membranes composed of inorganic nanowires / 3D coiled polymer fibers
[0099] 9. Dissolve 1.5g of the pre-oxidized inorganic nanowires prepared in step 8 in 9mL of acetonitrile, then add 1.5g of polyvinyl alcohol (Mw 300,000) and 0.15g of LiFSI, and stir again for 24h.
[0100] 10. Pour the mixed solution prepared in step 9 into the 15cm×20cm×20μm 3D coiled polymer fiber membrane prepared in step 5, and dry it in a vacuum oven for 48h to remove residual solvent, so as to prepare an inorganic nanowire / 3D coiled polymer fiber composite solid electrolyte membrane.
[0101] Example 3: Preparation of Organic-Inorganic Composite Solid Electrolyte Membrane
[0102] I. Preparation of 3D curled polymer fiber membranes
[0103] 1. Add 1.3g of polyphenylene sulfone (molecular weight Mw 80,000) to 10g of chlorosulfonic acid and stir in a water bath at 70°C for 4h for sulfonation treatment. Then, transfer the polyphenylene sulfone to distilled water and soak it for 24h to make it neutral. After that, dry it in an oven at 60°C to remove residual solvent to prepare sulfonated polyphenylene sulfone.
[0104] 2. Add 1.0 g of sulfonated polyphenylene sulfone prepared in step 1 to 10 mL of acetone and stir magnetically for 4 h to obtain the spinning solution of sulfonated polyphenylene sulfone;
[0105] 3. Mix 1.0 g of polyoxyethylene (Mw 400,000) with 0.2 g of LiDFOB and add the mixture to 10 mL of anisole. Stir continuously for 3 h to prepare a polyoxyethylene spinning solution.
[0106] 4. Transfer the two spinning solutions prepared above to two pipettes on parallel needles respectively, and draw the spinning solutions under a voltage of 30kV in a high-voltage electrospinning machine; the needle diameter corresponding to the sulfonated polyphenylene sulfone spinning solution is 0.2mm, and the needle diameter corresponding to the polyoxyethylene spinning solution is 0.1mm. Set the extrusion rates of the sulfonated polyphenylene sulfone spinning solution (1ml) and the polyoxyethylene spinning solution (1.5ml) to 0.5mL / h and 0.7mL / h respectively, the receiving distance to 20cm, and perform electrospinning for 8 hours at a temperature of 200℃.
[0107] 5. Remove the electrospun polymer film from the rotary receiver and dry it in a 50°C oven to remove residual solvent, so as to prepare a 3D rolled polymer fiber film (approximately 20 μm thick).
[0108] II. Preparation of Pre-oxidized Inorganic Nanowires
[0109] 6. Add 1.5g of N-methylpyrrolidone to 10mL of dimethylformamide and stir for 15min; then add cobalt carbonate (0.2g) and lanthanum carbonate (0.2g) in sequence, and stir again for 4h to obtain polyvinylpyrrolidone spinning solution;
[0110] 7. Transfer the spinning solution (1.0 mL) obtained in step 6 into the needle tube of the spinning machine (d = 0.2 mm). Under an electrostatic voltage of 40 kV and an air pressure of 0.3 MPa, spinning is carried out using the combined effects of high-speed airflow and electrostatic attraction. The extrusion rate of the spinning solution is 0.1 mL / h, the distance between the needle head and the collector is 50 cm, the spinning temperature is 200 °C, and the spinning time is 10 hours.
[0111] 8. Remove the fiber membrane from the collector and transfer it to a vacuum oven at 50°C to dry for 24 hours; then place the dried thin fiber membrane into a muffle furnace and heat it to 850°C at a temperature rate of 1.5°C / min, and sinter it in an air atmosphere at 850°C for 2 hours to prepare pre-oxidized inorganic nanowires.
[0112] III. Preparation of solid electrolyte membranes composed of inorganic nanowires / 3D coiled polymer fibers
[0113] 9. Dissolve 1.0 g of the inorganic nanowires prepared in step 8 in 10 mL of anisole, then add 1.5 g of polyethylene oxide (Mw 300,000) and 0.10 g of LiDFOB, and stir again for 24 h;
[0114] 10. Pour the mixed solution prepared in step 9 into the 15cm×20cm×20μm 3D coiled polymer fiber membrane prepared in step 5, and dry it in a vacuum oven for 48h to remove residual solvent, so as to prepare an inorganic nanowire / 3D coiled polymer fiber composite solid electrolyte membrane.
[0115] Example 4: Preparation of Organic-Inorganic Composite Solid Electrolyte Membrane
[0116] I. Preparation of 3D curled polymer fiber membranes
[0117] 1. Mix 1.0 g of polyethersulfone (molecular weight Mw 40,000) with 10 g of sulfur trioxide and stir in a water bath at 60 °C for 4 h for sulfonation treatment. Then, transfer the treated polyethersulfone to distilled water and soak it for 24 h to make it neutral. Finally, dry it in an oven at 50 °C to remove residual solvent to prepare sulfonated polyethersulfone (Mw 40,000).
[0118] 2. Add 1.0 g of sulfonated polyethersulfone prepared in step 1 to 9.5 mL of dimethylformamide and stir magnetically for 4 h to obtain the spinning solution of sulfonated polyethersulfone;
[0119] 3. Mix 1.0 g of polyethylene oxide (Mw400,000) with 0.15 g of LiTFSI and add the mixture to 10 mL of acetone. Stir continuously for 4 h to prepare a spinning solution of polyethylene oxide.
[0120] 4. Transfer the two spinning solutions prepared above to two pipettes on parallel needles respectively, and draw the spinning solutions under a voltage of 30kV in a high-voltage electrospinning machine; the needle diameter corresponding to the sulfonated polymer spinning solution is d=0.1mm, and the needle diameter corresponding to the polyethylene oxide spinning solution 1 is d=0.1mm. Set the extrusion rates of the sulfonated polyethersulfone spinning solution (1ml) and the polyethylene oxide spinning solution (1.5ml) to 0.6mL / h and 0.9mL / h respectively, and the receiving distance to 20cm for electrospinning.
[0121] 5. Remove the electrospun polymer film from the rotary receiver and dry it in a 60°C oven to remove residual solvent, so as to prepare a 3D rolled polymer fiber film (20μm thick).
[0122] II. Preparation of Pre-oxidized Inorganic Nanowires
[0123] 6. Add 1.5g of N-methylpyrrolidone to 9mL of dimethyl sulfoxide and stir for 15min; then add cobalt chloride (0.3g) and lanthanum chloride (0.3g) in sequence, and stir again for 4h to obtain N-methylpyrrolidone spinning solution;
[0124] 7. Transfer the spinning solution (1 mL) obtained in step 6 into the needle tube of the spinning machine (d = 0.2 mm). Under an electrostatic voltage of 40 kV and an air pressure of 0.2 MPa, spinning is carried out using the combined effects of high-speed airflow and electrostatic attraction. The extrusion rate of the spinning solution is 0.2 mL / h, the distance between the needle head and the collector is 30 cm, the spinning temperature is 200 °C, and the spinning time is 10 hours.
[0125] 8. Remove the fiber membrane from the collector and transfer it to a vacuum oven at 50°C to dry for 24 hours; then place the dried thin fiber membrane into a muffle furnace and heat it to 900°C at a temperature rate of 0.5°C / min, and sinter it in an air atmosphere at 900°C for 2 hours to prepare pre-oxidized inorganic nanowires.
[0126] III. Preparation of solid electrolyte membranes composed of inorganic nanowires / 3D coiled polymer fibers
[0127] 9. Dissolve 1.0 g of inorganic nanowires prepared in step 8 in 10 mL of acetonitrile, then add 1.0 g of polyethylene oxide and 0.1 g of LiTFSI, and stir again for 24 h.
[0128] 10. Pour the mixed solution prepared in step 9 into the 15cm×20cm×20μm 3D coiled polymer fiber membrane prepared in step 5, and dry it in a vacuum oven for 48h to remove residual solvent, and finally prepare an inorganic nanowire / 3D coiled polymer fiber composite solid electrolyte membrane.
[0129] Performance testing of solid electrolyte membranes composed of inorganic nanowires and 3D coiled polymer fibers:
[0130] Using the composite solid electrolyte membrane prepared in Example 1, SS|SE|SS coin cells were assembled. The specific assembly method is as follows: positive electrode shell | spring piece | spacer | SE | spacer | spring piece | negative electrode shell. Li|SE|SS coin cells were also assembled, with the specific assembly method as follows: positive electrode shell | spring piece | spacer | SE | lithium sheet | spacer | spring piece | negative electrode shell.
[0131] Electrochemical impedance spectroscopy was performed on the assembled coin cells, and the results are shown in [Figure number missing]. Figure 1 The specifications of the composite solid electrolyte membrane in this battery are: diameter: Φ = 16 mm; area: A = ~2.01 cm². 2 Thickness: d = ~30μm.
[0132] Depend on Figure 1 Therefore, the impedance is R = ~3.3Ω.
[0133] Ionic conductivity: σ=d / (R*A)≈3.77×10 -4S / cm; where: R is the measured impedance of the solid electrolyte membrane; d is the thickness of the membrane; A is the reaction area of the solid electrolyte membrane.
[0134] The LSV curves of the assembled Li|SE|SS coin cells were tested at a scan rate of 1 mV and a range of 0–6 V. The results are shown in [Figure number missing]. Figure 2 .Depend on Figure 2 The electrochemical window is approximately 4.1V.
[0135] Cycle performance (0.2 mA / cm) of the assembled Li|Li coin cell 2 The test was performed (0.2C cycle), and the results are shown below. Figure 3 .Depend on Figure 3 The cycle performance of the symmetrical battery (0.2 mA / cm) is known. 2 >500h.
[0136] The test results above show that the composite solid electrolyte membrane exhibits a performance of 10 at room temperature. -4 The high ionic conductivity of S / cm and the wide electrochemical window of over 4.1V, along with mechanical properties up to 7MPa, indicate that the electrolyte membrane can effectively suppress the growth of lithium dendrites, and a cycle performance of over 500h was measured.
Claims
1. A method for preparing an organic-inorganic composite solid electrolyte membrane, characterized in that, Includes the following steps:
1. Electrospinning was performed using sulfonated polymer solution and lithium salt-containing polyethylene oxide solution as spinning solution to obtain 3D crimped polymer fiber membranes.
2. Mix organic matter, cobalt salt, lanthanum salt and organic solvent to obtain organic spinning solution; spin the organic spinning solution and then sinter the resulting fiber membrane at high temperature to obtain pre-oxidized inorganic nanowires; 3. The pre-oxidized inorganic nanowires, polymer, lithium salt and organic solvent are mixed to obtain a mixed solution; then the mixed solution is coated on the surface of the 3D rolled polymer fiber membrane and dried to obtain an organic-inorganic composite solid electrolyte membrane.
2. The method for preparing the organic-inorganic composite solid electrolyte membrane according to claim 1, characterized in that, The preparation method of the organic-inorganic composite solid electrolyte membrane specifically includes the following steps: I. Preparation of 3D Curled Polymer Fiber Membranes (1) Dissolve the sulfonated polymer in an organic solvent to obtain a spinning solution of the sulfonated polymer; (2) Dissolve polyethylene oxide and lithium salt in an organic solvent to obtain a spinning solution of polyethylene oxide; (3) The two spinning solutions prepared above are transferred to two pipettes on a parallel needle for electrospinning. After electrospinning, the resulting polymer film is dried to obtain a 3D curled polymer fiber film. The steps (1) and (2) above are not in any particular order; II. Preparation of Pre-oxidized Inorganic Nanowires (4) Dissolve the organic matter in an organic solvent, then add cobalt salt and lanthanum salt to it, stir and mix to obtain an organic spinning solution; the organic matter is selected from at least one of the following: polyethylene oxide, polyvinyl alcohol, N-methylpyrrolidone; (5) The organic spinning solution obtained in step (4) is spun using the dual effects of high-speed airflow and electrostatic attraction; (6) After spinning, the resulting fiber membrane is dried, and then the dried fiber membrane is sintered at high temperature to obtain pre-oxidized inorganic nanowires. III. Preparation of Organic-Inorganic Composite Solid Electrolyte Membranes (7) Dissolve the pre-oxidized inorganic nanowires prepared in step (6) in an organic solvent, then add polymer and lithium salt to it, stir and mix to obtain a mixed solution; (8) The mixed solution described in step (7) is coated on the surface of the 3D curled polymer fiber membrane and dried to obtain a solid electrolyte membrane composed of inorganic nanowires / 3D curled polymer fibers.
3. The preparation method according to claim 2, characterized in that: In step (1), the sulfonated polymer is selected from at least one of the following: sulfonated polysulfone (SPSU), sulfonated polyether sulfone (SPESU), sulfonated polyphenylene sulfone (SPPSU); the weight average molecular weight of the sulfonated polymer is 30,000-80,000. Alternatively, in step (1), the organic solvent is selected from at least one of the following: dimethylformamide (DMF), dimethyl sulfoxide (DMSO), and acetone (AC).
4. The preparation method according to claim 2, characterized in that: In step (2), the weight-average molecular weight of the polyethylene oxide (PEO) is Mw100,000 to Mw800,000; Alternatively, in step (2), the lithium salt is selected from at least one of the following: lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(oxalateborate)borate (LiBOB), and lithium difluorooxalateborate (LiDFOB); Alternatively, in step (2), the organic solvent is selected from at least one of the following: acetonitrile, dimethylformamide (DMF), anisole, and chloroform (TM); Alternatively, in step (2), the mass ratio of the polyethylene oxide (PEO) to the lithium salt is (1-5):1; Alternatively, in step (2), the mass concentration of polyethylene oxide in the polyethylene oxide spinning solution is 10-15%.
5. The preparation method according to claim 2, characterized in that: In step (3), the electrospinning conditions are as follows: the needle diameter corresponding to the sulfonated polymer spinning solution is 0.1-0.5 mm, the extrusion rate of the sulfonated polymer spinning solution is set to 0.1-1 mL / h, the needle diameter corresponding to the polyethylene oxide spinning solution is 0.1-0.5 mm, the extrusion rate of the polyethylene oxide spinning solution is set to 0.1-1 mL / h, the receiver rotation speed is 60 rpm / min, the distance between the needle and the rotating receiver is 0.1-1 m, the spinning voltage is 30 kV, the spinning temperature is 200 ℃, and the spinning time is 1-10 h.
6. The preparation method according to claim 2, characterized in that: In step (4), the organic solvent is selected from at least one of the following: dimethylformamide (DMF), dimethyl sulfoxide (DMSO), and acetone (AC); Alternatively, in step (4), the cobalt salt is selected from at least one of the following: cobalt acetate, cobalt nitrate, cobalt carbonate, cobalt sulfate, cobalt fluoride, cobalt chloride, cobalt bromide, and cobalt iodide; Alternatively, in step (4), the lanthanum salt is selected from at least one of the following: lanthanum acetate, lanthanum nitrate, lanthanum chloride, and lanthanum carbonate; Alternatively, in step (4), the mass ratio of the organic matter, cobalt salt, and lanthanum salt is 1.5:(0.1-0.3):(0.15-0.3).
7. The preparation method according to claim 2, characterized in that: In step (5), the spinning conditions are as follows: the needle diameter is 0.1-1 mm, the extrusion rate of the spinning solution is set to 0.1-1 ml / h, the receiver rotation speed is 60 rpm, the distance between the needle and the collector is 0.1-1 m, the spinning is carried out under a voltage of 30-50 kV and a gas pressure of 0.1-10 MPa, the spinning temperature is 150-250℃, and the spinning time is 1-10 h. Alternatively, in step (6), the conditions for high-temperature sintering are: heating to 850-950℃ at a temperature rate of 0.5-2℃ / min and holding for sintering for 2 hours.
8. The preparation method according to claim 2, characterized in that: In step (7), the organic solvent is selected from at least one of the following: acetonitrile, dimethylformamide (DMF), anisole, and chloroform (TM); Alternatively, in step (7), the polymer is selected from at least one of the following: polyethylene oxide, polyvinyl alcohol; Alternatively, in step (7), the lithium salt is selected from at least one of the following: lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(oxalateborate)borate (LiBOB), and lithium di(fluorooxalateborate)borate (LiDFOB); Alternatively, in step (7), the mass ratio of the pre-oxidized inorganic nanowire, the polymer, and the lithium salt is (10-15):(10-15):(1-1.5); Alternatively, in step (8), the mass ratio of the mixed solution to the 3D coiled polymer fiber membrane is 10-20%.
9. The organic-inorganic composite solid electrolyte membrane prepared by any of the methods described in claims 1-8.
10. A lithium-ion solid-state battery, comprising a positive electrode, a negative electrode, and the organic-inorganic composite solid electrolyte membrane as described in claim 9.