A composite solid polymer electrolyte and its preparation method and application

Abstract

The present invention relates to the field of lithium-ion battery materials and electrochemical technology, and specifically to a highly elastic composite solid polymer electrolyte and its preparation method and application. More specifically, the present invention adopts TPU as an electrospinning polymer matrix, and forms a highly elastic fiber self-supporting film through electrospinning. At the same time, lithium-rich garnet and TPU are spun simultaneously, and the lithium-rich garnet can be evenly dispersed in the highly elastic fiber self-supporting film. In addition, an in-situ polymerization strategy is adopted to in-situ polymerize acrylate monomers having ether oxygen bonds and fluorine-containing groups on a highly elastic self-supporting fiber membrane, which can effectively reduce the battery interface impedance. The highly elastic fiber self-supporting membrane and in-situ polymerization are conducive to forming a stable electrode-electrolyte interface, inhibiting the growth of lithium dendrites, and improving the safety performance of the battery.

Description

Technical Field

[0001] The invention relates to the field of lithium ion battery materials and electrochemical technology, and in particular to a composite solid polymer electrolyte and a preparation method and application thereof. Background Art

[0002] Lithium-ion batteries have been widely used in energy storage, electric vehicles, laptops, mobile phones and other consumer electronics. However, the electrolytes used in commercial lithium-ion batteries are flammable, volatile and fluid, which hinder the reliability and safety of lithium-ion batteries. Solid electrolytes have intrinsic safety and good application potential. Existing solid electrolytes mainly include polymer solid electrolytes, inorganic solid electrolytes and composite solid electrolytes. Polymer solid electrolytes have low ionic conductivity, inorganic solid electrolytes are difficult to process and have large interface impedance. Composite solid electrolytes are based on polymer electrolytes and are compounded with inorganic components. They make up for the shortcomings of traditional polymer electrolytes, such as low ionic conductivity, narrow electrochemical window and low mechanical strength. There is hope to prepare solid electrolytes with excellent comprehensive performance.

[0003] However, the addition of traditional inorganic fillers is mainly mechanical mixing, and then solution casting or coating is used to obtain a composite polymer electrolyte. The inorganic filler has a high surface energy and poor interfacial compatibility with the polymer. During the physical mixing process, it is easy to agglomerate, difficult to disperse evenly, and difficult to form a continuous ion transmission path, which is not conducive to the improvement of ion conductivity. Therefore, the addition amount of inorganic fillers is usually relatively small. Secondly, the mechanical strength of the solid electrolyte can be improved by organic-inorganic composite, but the resilience of the electrolyte is not improved. The existing composite solid electrolytes basically do not have good resilience. During the battery charging and discharging process, it is difficult to adapt to the volume changes produced, which will destroy the electrode-electrolyte interface and is not conducive to the long-term stable operation of the battery.

[0004] At present, the problem of easy agglomeration of inorganic fillers can be solved by spinning polymers into continuous and uniform fibers through electrospinning technology, and compounding inorganic fillers on the fibers. For example, by compounding LPSCL inorganic particles and PVDF-TrFE electrospinning fibers, the ionic conductivity of the solid electrolyte is significantly improved (Adv.Energy Mater.2022,12,2200660). However, the impedance between the composite electrolyte and the electrode sheet is large, and the specific capacity is low under high current. Secondly, the current electrospinning fiber matrix is ​​mostly PEO, PVDF, PAN, etc. The fiber membrane has strong mechanical properties, but they do not have resilience. During the battery charging and discharging process, lithium metal, graphite and silicon negative electrodes will have large volume expansion and contraction with the lithium plating / stripping process. The existing fiber membrane does not have resilience and is difficult to adapt to volume changes, resulting in a poor interface. The interface impedance between the fiber membrane and the electrode is large, which is not conducive to the long-term stable operation of the battery. Therefore, in order to solve the practical problems of the above-mentioned existing composite polymer electrolytes, a composite polymer electrolyte with simple preparation process, high ionic conductivity, excellent rebound performance and low interface impedance is developed, which has important practical significance for promoting the industrialization development of solid electrolytes. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a highly elastic composite solid polymer electrolyte material and a preparation method for the problem that the inorganic fillers of the existing composite polymer electrolyte are difficult to disperse evenly and the fiber membrane has poor resilience. The present invention adopts TPU as an electrospinning polymer matrix to form a highly elastic fiber self-supporting membrane through electrospinning. At the same time, lithium-rich garnet and TPU are spun simultaneously, and the lithium-rich garnet can be evenly dispersed in the highly elastic fiber self-supporting membrane. In addition, an in-situ polymerization strategy is adopted to in-situ polymerize acrylic ester monomers having ether oxygen bonds and fluorine-containing groups on a highly elastic self-supporting fiber membrane, which can effectively reduce the battery interface impedance. The highly elastic fiber self-supporting membrane and in-situ polymerization are conducive to forming a stable electrode-electrolyte interface, inhibiting the growth of lithium dendrites, and improving the safety performance of the battery.

[0006] The first aspect of the present invention provides a composite solid polymer electrolyte, comprising an acrylic polymer, a composite fiber self-supporting membrane, a lithium salt, and an ion solution.

[0007] in,

[0008] The fiber self-supporting membrane comprises a polymer matrix and lithium-rich garnet inorganic particles.

[0009] The polymer matrix is ​​at least one of polyurethane and polyacrylonitrile, polyvinyl pyrrolidone, polyvinylidene fluoride-hexafluoropropylene, and polyvinylidene fluoride, and is a three-dimensional fiber mesh formed by electrospinning technology, and the lithium-rich garnet inorganic particles are attached to the surface of the three-dimensional fiber mesh.

[0010] According to a specific embodiment of the present invention, the lithium-rich garnet inorganic particles include at least one of lithium lanthanum zirconium oxide and lithium lanthanum zirconium tantalum oxide (LLZTO).

[0011] According to a specific embodiment of the present invention, the mass ratio of the polymer matrix to the lithium-rich garnet inorganic particles is 100:(10-50).

[0012] According to a specific embodiment of the present invention, the acrylic polymer is formed by polymerizing a polymer A1 containing an ether oxygen bond, a polymer A2 containing a fluorine group, and a polymer B having two C=C double bonds.

[0013] According to a specific embodiment of the present invention, the polymer A1 comprises poly(ethylene glycol) methacrylate and / or polyethylene glycol methyl ether methacrylate,

[0014] The polymer A2 includes at least one of 2,2,3,4,4,4-hexafluorobutyl acrylate, 2,2,3,3,4,4,4-heptafluorobutyl methacrylate, and 1H,1H,11H-perfluoroundecyl acrylate.

[0015] The polymer B comprises polyethylene glycol diacrylate and / or polyethylene glycol dimethacrylate;

[0016] The volume ratio of polymer A1, polymer A2 and polymer B is 10:5:0.66.

[0017] According to a specific embodiment of the present invention, the lithium salt includes lithium bis(fluorosulfonyl)imide and / or lithium bis(trifluorosulfonyl)imide, and the concentration of the lithium salt is 1-3 mol / L.

[0018] According to a specific embodiment of the present invention, the ionic solution includes at least one of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, 1-methylimidazolium trifluoromethanesulfonate, and tributyl(methyl)phosphine dimethyl phosphate.

[0019] According to a specific embodiment of the present invention, the mass ratio of the ionic liquid to polymer A1 and polymer A2 is (10-50):63:37.

[0020] The second aspect of the present invention provides a method for preparing the composite solid polymer electrolyte described in the first aspect, comprising:

[0021] S1, taking compound a and compound b, and independently dissolving them with lithium-rich garnet inorganic particles in a solvent, to obtain a mixed solvent 1 without compound b and a mixed solution 2 without compound a, respectively;

[0022] S2, electrospinning the mixed solvent 2, and then continuing to electrospin the mixed solvent 1 on the obtained spun fiber membrane, and then electrospinning the mixed solvent 2 again on this basis, to obtain a fiber self-supporting membrane;

[0023] S3, mixing polymer A1, polymer A2, polymer B, lithium salt and ion solution to obtain mixed solution 3;

[0024] S4, adding an initiator to the mixed solution 3 to obtain a precursor solution;

[0025] S5, dropping the precursor solution into the fiber self-supporting film, assembling it using the button battery assembly method to obtain an assembled button battery;

[0026] S6, promoting monomer polymerization of the button battery in a heating environment to obtain the composite solid polymer electrolyte,

[0027] in,

[0028] The compound a is polyurethane, and the compound b includes at least one of polyacrylonitrile, polyvinyl pyrrolidone, polyvinylidene fluoride-hexafluoropropylene, and polyvinylidene fluoride.

[0029] According to a specific embodiment of the present invention, in step S1, the lithium-rich garnet inorganic particles include at least one of lithium lanthanum zirconium oxide and lithium lanthanum zirconium tantalum oxide (LLZTO).

[0030] According to a specific embodiment of the present invention, the mass ratio of compound a to compound b is 3:1;

[0031] According to a specific embodiment of the present invention, in the mixed solvent 1, the mass ratio of the compound a to the lithium-rich garnet inorganic particles is 10:(1-5).

[0032] According to a specific embodiment of the present invention, in the mixed solvent 2, the mass ratio of the compound b to the lithium-rich garnet inorganic particles is 10:(1-5).

[0033] According to a specific embodiment of the present invention, the solvent includes at least one of DMF, DMAc and acetone.

[0034] According to a specific embodiment of the present invention, in step S3, the polymer A1, polymer A2, and polymer B are respectively polymer A1 containing an ether oxygen bond, polymer A2 containing a fluorine group, and polymer B having two C=C double bonds;

[0035] According to a specific embodiment of the present invention, the polymer A1 comprises poly(ethylene glycol) methacrylate and / or polyethylene glycol methyl ether methacrylate,

[0036] The polymer A2 includes at least one of 2,2,3,4,4,4-hexafluorobutyl acrylate, 2,2,3,3,4,4,4-heptafluorobutyl methacrylate, and 1H,1H,11H-perfluoroundecyl acrylate.

[0037] The polymer B comprises polyethylene glycol diacrylate and / or polyethylene glycol dimethacrylate;

[0038] The volume ratio of polymer A1, polymer A2 and polymer B is 10:5:0.66.

[0039] According to a specific embodiment of the present invention, the lithium salt includes lithium bis(fluorosulfonyl)imide and / or lithium bis(trifluorosulfonyl)imide, and the concentration of the lithium salt is 1-3 mol / L.

[0040] According to a specific embodiment of the present invention, the ionic solution includes at least one of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, 1-methylimidazolium trifluoromethanesulfonate, and tributyl(methyl)phosphine dimethyl phosphate.

[0041] According to a specific real-time solution of the present invention, the mass ratio of the ionic liquid to polymer A1 and polymer A2 is (10-50):63:37.

[0042] According to a specific embodiment of the present invention, in step S3, the initiator includes AIBN and benzoyl peroxide.

[0043] According to a specific embodiment of the present invention, the mass percentage of the initiator in the precursor solution is (0.05-0.2)%.

[0044] According to the specific real-time solution of the present invention, in step S6, the temperature during heating is 55-85 degrees Celsius.

[0045] The third aspect of the present invention provides use of the composite solid polymer electrolyte described in the first aspect in preparing a lithium battery.

[0046] The highly elastic composite solid polymer electrolyte and solid-state battery provided by the present invention are prepared by electrostatically spinning a polymer matrix such as TPU and lithium-rich garnet into a highly elastic fiber self-supporting film; at the same time, an in-situ polymerization strategy is adopted to in-situ polymerize acrylate monomers on the highly elastic fiber self-supporting film to obtain a highly elastic composite solid polymer electrolyte. TPU has excellent mechanical strength and resilience, can inhibit the growth of lithium dendrites, adapt to the volume changes produced during the charge and discharge process, and ensure the long-term stable cycle of the battery. In addition, the ionic conductivity of lithium-rich garnet and ionic liquid is relatively high, and their introduction into the solid electrolyte can improve the ionic conductivity of the solid electrolyte. The in-situ polymerized acrylate monomers can form a stable electrode-electrolyte interface, reduce the interface impedance, and ensure the high safety performance of the lithium-ion battery.

[0047] Compared with the prior art, the present invention has the following beneficial effects:

[0048] 1. The present invention uses electrospinning technology, polymers such as TPU as a matrix, and lithium-rich garnet as an inorganic filler to successfully prepare a fiber membrane with high mechanical strength and excellent resilience. The lithium-rich garnet is evenly dispersed in the elastic fiber membrane, successfully solving the problem that the inorganic filler is easy to agglomerate and difficult to disperse evenly. In addition, the lithium-rich garnet itself has high ionic conductivity and high chemical stability, can form a new lithium ion transmission channel, and can further improve the ionic conductivity.

[0049] 2. The present invention adopts an in-situ polymerization strategy to in-situ polymerize acrylate monomers with ether oxygen bonds and fluorine-containing groups on a highly elastic self-supporting fiber membrane, thereby improving the unstable contact between the fiber membrane and the electrode material and the large interface impedance. Acrylate polymers have good compatibility with lithium metal and low interface impedance, which can improve the deposition morphology of lithium ions, inhibit lithium dendrites, and ensure the high safety performance of lithium-ion batteries. The material design and preparation technology of the present invention is simple, controllable, and practical, providing a new idea for the preparation of highly elastic composite solid polymer electrolytes and related batteries.

[0050] BRIEF DESCRIPTION OF THE DRAWINGS In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0051] Figure 1 These are pictures of the precursor solution prepared in Example 1 of the present invention before and after polymerization, wherein picture a is before polymerization and picture b is after polymerization.

[0052] Figure 2This is a test of the resilience performance of the highly elastic fiber self-supporting membrane prepared in Example 1 of the present invention. The fiber membrane was stretched to 100%, and then returned to the initial state, and repeated 10 times, with a stretching speed of 50 mm min -1 .

[0053] Figure 3 This is a mechanical property test of the highly elastic fiber self-supporting membrane prepared in Example 1 of the present invention. The fiber membrane is pulled apart at a stretching speed of 50 mm min -1 .

[0054] Figure 4 This is an electron microscope photo of the highly elastic fiber self-supporting membrane prepared in Example 1. LLZTO inorganic particles are attached to the fiber surface. The scale is 2 μm.

[0055] Figure 5 This is the thermogravimetric analysis of the highly elastic fiber self-supporting membrane prepared in Example 1. The fiber membrane was heated from room temperature to 800°C at a rate of 10°C min -1 , the test environment is argon.

[0056] Figure 6 This is the X-ray diffraction spectrum (XRD) of the highly elastic fiber self-supporting membrane and LLZTO inorganic particles prepared in Example 1. The scanning speed is 10°min -1 , the scanning angle is 10°-90°.

[0057] Figure 7 This is the impedance spectrum of the highly elastic fiber self-supporting membrane prepared in Example 1 after being combined with the polymer electrolyte. The test frequency is 10 6 -1Hz, 5mV amplitude.

[0058] Figure 8 It is the electrochemical window of the highly elastic composite solid polymer electrolyte prepared in Example 1.

[0059] Fig. 9 The Li / / Li symmetric battery prepared in situ with a highly elastic composite solid polymer electrolyte prepared in Example 1 was -2 , 0.1mAh cm -2 The voltage-time curve below.

[0060] Fig.10 A lithium battery was assembled using lithium iron phosphate (LiFePO4) as the positive electrode and the highly elastic composite solid polymer electrolyte prepared in Example 1. The battery was charged at a rate of 0.5C (1C = 170 mAh g) in a voltage range of 2.5 V to 4 V. -1 ) cycle performance diagram.

[0061] Fig.11The mechanical properties of the fiber self-supporting membrane prepared in Example 2 of the present invention were tested at a stretching speed of 50 mm / min. -1 .

[0062] Fig.12 This is the impedance spectrum of the highly elastic fiber self-supporting membrane prepared in Example 3 of the present invention and the PMMA polymer electrolyte after compounding. The test frequency is 10 6 -1Hz, 5mV amplitude. DETAILED DESCRIPTION

[0063] Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0064] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. Further, in the description of the present invention, unless otherwise specified, the meaning of "plurality" is two or more.

[0065] In this document, the terms “contain”, “include” or “comprise” are open expressions, that is, they include the contents specified in the present invention but do not exclude other contents.

[0066] As used herein, the terms "optionally", "optional" or "optionally" generally mean that the subsequently described event or circumstance may but need not occur, and that the description includes instances where the event or circumstance occurs and instances where it does not.

[0067] The technical problem to be solved by the present invention is to provide a highly elastic composite solid polymer electrolyte material and a preparation method thereof in view of the problem that the inorganic fillers of the existing composite polymer electrolyte are difficult to be evenly dispersed and the fiber membrane has poor resilience. The present invention adopts TPU as an electrostatic spinning polymer matrix to form a highly elastic fiber self-supporting membrane through electrostatic spinning. At the same time, lithium-rich garnet and TPU are spun simultaneously, and the lithium-rich garnet can be evenly dispersed in the highly elastic fiber self-supporting membrane. In addition, the in-situ polymerization strategy is adopted to effectively reduce the battery interface impedance. The highly elastic fiber self-supporting membrane and in-situ polymerization are conducive to forming a stable electrode-electrolyte interface, inhibiting the growth of lithium dendrites, and improving the safety performance of the battery.

[0068] In order to achieve the above technical objectives, the present invention adopts the following technical solutions:

[0069] The present invention provides a highly elastic composite solid polymer electrolyte material and a preparation method thereof, which adopts electrostatic spinning and in-situ polymerization strategies to combine a highly elastic fiber self-supporting membrane and a polymer electrolyte, thereby reducing the interfacial impedance of the battery, improving the ionic conductivity, inhibiting the growth of lithium dendrites, and improving the safety performance of the battery.

[0070] The present invention provides a method for preparing the above-mentioned highly elastic composite solid polymer electrolyte by electrospinning and in-situ polymerization, which specifically comprises the following steps:

[0071] 1) The highly elastic fiber self-supporting membrane is prepared by using electrospinning technology, and the highly elastic fiber self-supporting membrane is dried and then cut into discs.

[0072] 2) In an argon protective atmosphere in a glove box, polymer A and polymer B are mixed, lithium salt is added, and the mixture is stirred evenly.

[0073] 3) Add ionic liquid to the mixed solution obtained in step 2) and stir evenly.

[0074] 4) Adding an initiator to the mixed solution obtained in step 3) and dispersing the mixture uniformly to obtain a precursor solution.

[0075] 5) According to the button battery assembly method, the negative electrode, the fiber self-supporting film and the positive electrode are placed in sequence, and the precursor solution is added before and after the fiber self-supporting film is placed, and the button battery assembly is completed. The battery is heated at 60-80°C to promote complete polymerization of the monomers to form a highly elastic organic-inorganic composite solid polymer electrolyte.

[0076] According to the above scheme, in step 1), the electrospinning technology is used to prepare a highly elastic fiber self-supporting membrane, and the spinning parameters are: voltage 14-18kV, the propulsion speed of the precursor solution is 0.08-0.12mm min -1 , the acceptance distance between the needle and the base is 15-25cm.

[0077] According to the above scheme, in the step 1), the highly elastic fiber self-supporting membrane comprises at least polyurethane (TPU), and at the same time comprises one or more of polyacrylonitrile (PAN), polyvinyl pyrrolidone (PVP), polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP), and polyvinylidene fluoride (PVDF). The solvent used is DMF, and the mass ratio of polymer to solvent is (10-30):100.

[0078] According to the above scheme, in step 1), lithium-rich garnet inorganic particles are added to the highly elastic fiber membrane, the lithium-rich garnet is at least one of LLZO and LLZTO, and the mass ratio of the inorganic solid electrolyte and the polymer in the fiber self-supporting membrane is (10-50):100.

[0079] According to the above scheme, in step 2), the lithium salt is lithium bis(fluorosulfonyl)imide (LiFSI) with a concentration of 1-3 mol / L.

[0080] According to the above scheme, in the step 2), polymer A includes polymer A1 and polymer A2, wherein polymer A1 includes poly(ethylene glycol) methacrylate (PEGMA) and / or polyethylene glycol methyl ether methacrylate (PEGMEMA); polymer A2 includes one or more of 2,2,3,4,4,4-hexafluorobutyl acrylate (HFA), 2,2,3,3,4,4,4-heptafluorobutyl methacrylate (HFMA), and 1H,1H,11H-perfluoroundecyl acrylate (PFA). The ether oxygen bond in polymer A can coordinate with lithium ions and conduct lithium ions through segment movement. The fluorine-containing group can promote the dissociation of lithium salts and improve the antioxidant properties of the polymer. Polymer B is one of polyethylene glycol diacrylate (PEGDA) and polyethylene glycol dimethacrylate (PEGDMA). Polymer B contains two C=C double bonds and can be used as a crosslinking agent to form a three-dimensional crosslinked network with polymer A through free radical polymerization. The molar ratio of the two is 100:(1-5). The condition for the polymerization reaction is that the carbon-carbon double bond is heated, and the initiator generates free radicals, which can open the carbon-carbon double bond and form a polymer through chain growth. Containing two carbon-carbon double bonds will form two chain growth sites, thereby forming a cross-linked structure. The cross-linked structure mainly improves the mechanical strength of the polymer, enhances the mechanical properties, and improves the ability to inhibit lithium dendrites.

[0081] According to a specific embodiment of the present invention, the prepared three-dimensional cross-linked network is an acrylic polymer, and the chemical structure is as described in Formula 1:

[0082]

[0083] According to the above scheme, in step 3), the ionic liquid is 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt (EMIMTFSI), and the mass ratio of the ionic liquid to the polymer A is (10-50):100.

[0084] According to the above scheme, in step 4), the initiator is azobisisobutyronitrile (AIBN), and the added content is 0.1 wt% of polymer A.

[0085] According to the above scheme, in step 5), the battery is placed in an environment of 60-80° C. and heated for 6-12 hours to finally obtain a highly elastic composite solid polymer electrolyte.

[0086] The invention provides a highly elastic composite solid polymer electrolyte material prepared by the preparation method.

[0087] The present invention further provides the use of the highly elastic composite solid polymer electrolyte material as a lithium ion battery electrolyte material.

[0088] The highly elastic composite solid polymer electrolyte and solid-state battery provided by the present invention are prepared by electrostatically spinning a polymer matrix such as TPU and lithium-rich garnet into a highly elastic fiber self-supporting film; at the same time, an in-situ polymerization strategy is adopted to in-situ polymerize acrylate monomers on the highly elastic fiber self-supporting film to obtain a highly elastic composite solid polymer electrolyte. TPU has excellent mechanical strength and resilience, can inhibit the growth of lithium dendrites, adapt to the volume changes produced during the charge and discharge process, and ensure the long-term stable cycle of the battery. In addition, the ionic conductivity of lithium-rich garnet and ionic liquid is relatively high, and their introduction into the solid electrolyte can improve the ionic conductivity of the solid electrolyte. The in-situ polymerized acrylate monomers can form a stable electrode-electrolyte interface, reduce the interface impedance, and ensure the high safety performance of the lithium-ion battery.

[0089] The purchase sources and product numbers of the main reagents used in this application are shown in Table 1.

[0090] Table 1

[0091] Reagent name Where to buy Part Number TPU Quduo Industry 1185A LLZTO Duoduo Chemical NE-000250 DMF Aladdin D112000-500ml PAN Ron R097443-50g PVP Aladdin P110610-100g PEGMA Ron R094354-25ml HFA Aladdin H156911-5g PEGDA Ron R018544-25ml LiFSI Duoduo Chemical NE-000027 EMIMTFSI Ron R016633-25g AIBN Ron R017995-5g MMA Aladdin M109629-500ml

[0092] The scheme of the present disclosure will be explained below in conjunction with the examples. Those skilled in the art will appreciate that the following examples are only used to illustrate the present disclosure and should not be considered to limit the scope of the present disclosure. If no specific techniques or conditions are specified in the examples, the techniques or conditions described in the literature in the art or the product instructions are used. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be obtained commercially. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the art without making creative work are within the scope of protection of the present invention.

[0093] Example 1

[0094] The composite solid polymer electrolyte and solid-state battery of this embodiment are prepared by the following steps:

[0095] 1) 3 g TPU and 0.3 g LLZTO were dissolved in 10 g DMF to obtain a mixed solution 1. The electrospinning parameters were: voltage 17 kV, propulsion speed 0.1 mm min -1 , receiving distance 20cm. 0.5g PAN, 0.5g PVP and 0.2g LLZTO were dissolved in 10g DMF to obtain mixed solution 2. Electrospinning parameters: voltage 14kV, propulsion speed 0.1mm min -1, receiving distance 20cm. Electrospinning was performed in the order of mixed solution 2, mixed solution 1, and mixed solution 2 to form a sandwich structure of PAN-TPU-PAN, which was then dried and cut into discs with a diameter of 17mm.

[0096] 2) Under the argon protective atmosphere of the glove box, 1 mL of PEGMA, 0.5 mL of HFA and 66 μL of PEGDA were weighed and mixed evenly, and 0.281 g of LiFSI (1 M) and 0.3 g of EMIMTFSI were added thereto and stirred evenly.

[0097] 3) Add 0.1 wt % of initiator AIBN to the mixed solution and stir evenly to obtain a precursor solution.

[0098] 4) According to the button battery assembly method, the obtained precursor solution is added dropwise to the PAN-TPU-PAN fiber membrane, and the button battery is assembled. The battery is then heated at 60°C for 12 hours, and the monomer is completely polymerized to form a composite solid polymer electrolyte inside the battery, wherein: Figure 1 These are pictures of the precursor solution before and after polymerization. Figure 1 Figure a is the picture before aggregation, and figure b is the picture after aggregation.

[0099] The inventors conducted a resilience test on the fiber self-supporting membrane (TPU-PAN-PVP fiber membrane) prepared in this embodiment. The test method is to stretch the fiber membrane to 100%, then return to the initial state, repeat 10 times, and the stretching speed is 50mmmin- 1 The results are as follows Figure 2 As shown, the fiber self-supporting membrane prepared in this embodiment has excellent resilience and can still return to its original state after being stretched 10 times.

[0100] The inventors conducted a mechanical property test on the fiber self-supporting membrane (TPU-PAN-PVP fiber membrane) prepared in this embodiment. The test method is to break the fiber membrane at a stretching speed of 50 mm min- 1 The results are as follows Figure 3 As shown, the fiber self-supporting membrane prepared in this example has excellent mechanical properties, with an elongation at break of 325% and a breaking strength of 1.8 MPa.

[0101] The inventors conducted electron microscope scanning on the fiber self-supporting membrane (TPU-PAN-PVP fiber membrane) prepared in this example, and the results are as follows: Figure 4 As shown, the scale of the electron microscope scanning image is 2 microns. LLZTO inorganic particles are attached to the surface of the fiber. The results show that the fiber has a uniform diameter and has many pores, which are easy to be infiltrated by the polymer precursor solution. The LLZTO inorganic particles attached to the surface are evenly distributed and can form a lithium ion transmission channel.

[0102] The inventors conducted a thermogravimetric analysis on the fiber self-supporting membrane (TPU-PAN-PVP fiber membrane) prepared in this embodiment. The specific method is to heat the fiber membrane from room temperature to 800°C at a heating rate of 10°C min -1 , the test environment is argon, the results are as follows Figure 5 The above-mentioned data show that the fiber membrane has excellent thermal stability. When the temperature is raised to 288° C., the weight of the fiber membrane decreases by 5%, and the fiber membrane has a relatively high thermal decomposition temperature.

[0103] The inventors conducted X-ray diffraction spectroscopy analysis on the fiber self-supporting membrane (TPU-PAN-PVP fiber membrane) and LLZTO inorganic particles prepared in this example, with a scanning speed of 10°min -1 , the scanning angle is 10°-90°, the results are as follows Figure 6 As shown, it is shown that the diffraction characteristic peak of LLZTO inorganic particles appears in the elastic fiber membrane prepared in this example, indicating that the inorganic particles are successfully added into the elastic fiber membrane.

[0104] The inventors conducted impedance tests on the composite solid polymer electrolyte prepared in this embodiment at a test frequency of 10 6 -1Hz, amplitude is 5mV, the result is as follows Figure 7 As shown in Figure 2, the room temperature ionic conductivity of the highly elastic composite solid polymer electrolyte can be calculated from the impedance spectrum to be 8.05×10 -4 S cm -1 , higher ionic conductivity is conducive to the transmission of lithium ions. High ionic conductivity is the result of the combined effect of LLZTO inorganic filler, ionic liquid and in-situ polymerized acrylate monomers. Among them, the -O, -F, =O polar groups on the acrylate monomer can promote the dissociation of lithium salts and conduct lithium ions through chain segment movement.

[0105] The inventors tested the electrochemical window of the composite solid polymer electrolyte prepared in this embodiment, and the results are as follows: Figure 8 As shown, the electrochemical window of the composite solid polymer electrolyte prepared in this example is 5.2 V. The high electrochemical window indicates that it has high anti-oxidation stability.

[0106] The inventors tested the compatibility between the composite solid polymer electrolyte prepared in this embodiment and the lithium negative electrode. The Li / / Li symmetric battery prepared using the composite solid polymer electrolyte had a -2 , 0.1mAh cm -2 The voltage-time curve under Fig. 9 As shown, it shows that its stable cycle can exceed 300h, and the overpotential is about 100mV. It can be seen that the highly elastic composite solid polymer electrolyte has good compatibility with the lithium negative electrode.

[0107] The inventors tested the cycle performance of the composite solid polymer electrolyte prepared in this embodiment. The testing method is as follows: lithium iron phosphate (LiFePO4) is used as the positive electrode, and a lithium battery is assembled using the highly elastic composite solid polymer electrolyte. The battery is charged at a rate of 0.5C (1C = 170 mAh g) in a voltage range of 2.5V to 4V. -1 ) to test the cycle performance, the results are as follows Fig.10 As shown, the composite solid polymer electrolyte prepared in this embodiment has an initial discharge capacity of 141.9 mAh g -1 After 50 cycles, the battery capacity retention rate was 89.8%, and the cycle performance was relatively stable.

[0108] Example 2

[0109] The composite solid polymer electrolyte and solid-state battery of this embodiment are prepared by the following steps:

[0110] 1) Dissolve 1 g PAN and 0.2 g LLZTO in 10 g DMF. Electrospinning parameters: voltage 14 kV, propulsion speed 0.1 mm min -1 , receiving distance 20cm. Electrospinning into fiber membrane, then drying and cutting into discs with a diameter of 17mm.

[0111] 2) Under the argon protective atmosphere of the glove box, 1 mL of PEGMA, 0.5 mL of HFA and 66 μL of PEGDA were weighed and mixed evenly, and 0.281 g of LiFSI (1 M) and 0.3 g of EMIMTFSI were added thereto and stirred evenly.

[0112] 3) Add 0.1 wt % of initiator AIBN to the mixed solution and stir evenly to obtain a precursor solution.

[0113] 4) According to the button cell assembly method, the obtained precursor solution is added dropwise to the PAN fiber membrane and the button cell is assembled. The battery is then heated at 60°C for 12 hours until the monomer is completely polymerized to form a composite solid polymer electrolyte inside the battery.

[0114] Example 3

[0115] The composite solid polymer electrolyte and solid-state battery of this embodiment are prepared by the following steps:

[0116] 1) 3 g TPU and 0.3 g LLZTO were dissolved in 10 g DMF to obtain a mixed solution 1. The electrospinning parameters were: voltage 17 kV, propulsion speed 0.1 mm min -1, receiving distance 20cm. 0.5g PAN, 0.5g PVP and 0.2g LLZTO were dissolved in 10g DMF to obtain mixed solution 2. Electrospinning parameters: voltage 14kV, propulsion speed 0.1mm min -1 , receiving distance 20cm. Electrospinning was performed in the order of mixed solution 2, mixed solution 1, and mixed solution 2 to form a sandwich structure of PAN-TPU-PAN, which was then dried and hot pressed and cut into discs with a diameter of 17mm.

[0117] 2) Under the argon protective atmosphere of the glove box, weigh 1 mL of MMA, add 0.281 g of LiFSI (1 M) and 0.3 g of EMIMTFSI thereto, and stir evenly.

[0118] 3) Add 0.1 wt % of initiator AIBN to the mixed solution and stir evenly to obtain a precursor solution.

[0119] 4) According to the button battery assembly method, the obtained precursor solution was added dropwise to the PAN-TPU-PAN fiber membrane, and the button battery was assembled. The battery was then heated at 60°C for 12 hours until the monomers were completely polymerized and a composite solid polymer electrolyte was formed inside the battery.

[0120] Example 4

[0121] The composite solid polymer electrolyte and solid-state battery of this embodiment are prepared by the following steps:

[0122] 1) 3 g TPU and 0.3 g LLZTO were dissolved in 10 g DMF to obtain a mixed solution 1. The electrospinning parameters were: voltage 17 kV, propulsion speed 0.1 mm min -1 , receiving distance 20cm. 1g PVP and 0.1g LLZTO were dissolved in 10g DMF to obtain mixed solution 2. Electrospinning parameters: voltage 12kV, propulsion speed 0.1mm min -1 , receiving distance 20cm. Electrospinning was performed in the order of mixed solution 2, mixed solution 1, and mixed solution 2 to form a sandwich structure of PVP-TPU-PVP, which was then dried and cut into discs with a diameter of 17mm.

[0123] 2) Under the argon protective atmosphere of the glove box, 1.5 mL of HFA and 50 μL of PEGDA were weighed and mixed evenly, and 0.281 g of LiFSI (1 M) and 0.3 g of EMIMTFSI were added thereto and stirred evenly.

[0124] 3) Add 0.1 wt % of initiator AIBN to the mixed solution and stir evenly to obtain a precursor solution.

[0125] 4) According to the button battery assembly method, the obtained precursor solution was added dropwise to the PVP-TPU-PVP fiber membrane, and the button battery was assembled. The battery was then heated at 60°C for 12 hours until the monomers were completely polymerized and a composite solid polymer electrolyte was formed inside the battery.

[0126] Example 5

[0127] The composite solid polymer electrolyte and solid-state battery of this embodiment are prepared by the following steps:

[0128] 1) 3 g TPU and 0.6 g LLZTO were dissolved in 10 g DMF to obtain a mixed solution 1. The electrospinning parameters were: voltage 18 kV, propulsion speed 0.08 mm min -1 , receiving distance 20 cm. 0.5 g PAN, 0.5 g PVP and 0.2 g LLZTO were dissolved in 10 g DMF to obtain mixed solution 2. Electrospinning parameters: voltage 14 kV, propulsion speed 0.1 mm min -1 , receiving distance 20cm. Electrospinning was performed in the order of mixed solution 2, mixed solution 1, and mixed solution 2 to form a sandwich structure of PAN-TPU-PAN, which was then dried and cut into discs with a diameter of 17mm.

[0129] 2) Under the argon protective atmosphere of the glove box, 1 mL of PEGMA, 0.5 mL of HFA and 66 μL of PEGDA were weighed and mixed evenly, and 0.281 g of LiFSI (1 M) and 0.3 g of EMIMTFSI were added thereto and stirred evenly.

[0130] 3) Add 0.1 wt % of initiator AIBN to the mixed solution and stir evenly to obtain a precursor solution.

[0131] 4) According to the button battery assembly method, the obtained precursor solution was added dropwise to the PAN-TPU-PAN fiber membrane, and the button battery was assembled. The battery was then heated at 60°C for 12 hours until the monomers were completely polymerized and a composite solid polymer electrolyte was formed inside the battery.

[0132] Example 6

[0133] The composite solid polymer electrolyte and solid-state battery of this embodiment are prepared by the following steps:

[0134] 1) 3 g TPU and 0.3 g LLZTO were dissolved in 10 g DMF to obtain a mixed solution 1. The electrospinning parameters were: voltage 17 kV, propulsion speed 0.1 mm min -1, receiving distance 20 cm. 1 g PVDF and 0.2 g LLZTO were dissolved in 10 g DMF to obtain mixed solution 2. Electrospinning parameters: voltage 15 kV, propulsion speed 0.12 mm min -1 , receiving distance 20cm. Electrospinning was performed in the order of mixed solution 2, mixed solution 1, and mixed solution 2 to form a sandwich structure of PVDF-TPU-PVDF, which was then dried and cut into discs with a diameter of 17mm.

[0135] 2) Under the argon protective atmosphere of the glove box, 1 mL of PEGMA, 0.5 mL of HFA and 66 μL of PEGDA were weighed and mixed evenly, and 0.281 g of LiFSI (1 M) and 0.3 g of EMIMTFSI were added thereto and stirred evenly.

[0136] 3) Add 0.1 wt % of initiator AIBN to the mixed solution and stir evenly to obtain a precursor solution.

[0137] 4) According to the button cell assembly method, the obtained precursor solution was added dropwise to the PVDF-TPU-PVDF fiber membrane, and the button cell was assembled. The battery was then heated at 60°C for 12 hours until the monomers were completely polymerized and a composite solid polymer electrolyte was formed inside the battery.

[0138] Example 7

[0139] The composite solid polymer electrolyte and solid-state battery of this embodiment are prepared by the following steps:

[0140] 1) 3 g TPU and 0.3 g LLZO were dissolved in 10 g DMF to obtain a mixed solution 1. The electrospinning parameters were: voltage 17 kV, propulsion speed 0.1 mm min -1 , receiving distance 15 cm. 0.5 g PAN, 0.5 g PVP and 0.2 g LLZO were dissolved in 10 g DMF to obtain mixed solution 2. Electrospinning parameters: voltage 14 kV, propulsion speed 0.1 mm min -1 , receiving distance 20cm. Electrospinning was performed in the order of mixed solution 2, mixed solution 1, and mixed solution 2 to form a sandwich structure of PAN-TPU-PAN, which was then dried and hot pressed and cut into discs with a diameter of 17mm.

[0141] 2) Under the argon protective atmosphere of the glove box, 1 mL of PEGMA, 0.5 mL of HFA and 66 μL of PEGDA were weighed and mixed evenly, and 0.281 g of LiFSI (1 M) and 0.3 g of EMIMTFSI were added thereto and stirred evenly.

[0142] 3) Add 0.1 wt % of initiator AIBN to the mixed solution and stir evenly to obtain a precursor solution.

[0143] 4) According to the button battery assembly method, the obtained precursor solution was added dropwise to the PAN-TPU-PAN fiber membrane, and the button battery was assembled. The battery was then heated at 60°C for 12 hours until the monomers were completely polymerized and a composite solid polymer electrolyte was formed inside the battery.

[0144] Example 8

[0145] The composite solid polymer electrolyte and solid-state battery of this embodiment are prepared by the following steps:

[0146] 1) 3 g TPU and 0.3 g LLZTO were dissolved in 10 g DMF to obtain a mixed solution 1. The electrospinning parameters were: voltage 17 kV, propulsion speed 0.1 mm min -1 , receiving distance 20cm. 0.5g PAN, 0.5g PVP and 0.2g LLZTO were dissolved in 10g DMF to obtain mixed solution 2. Electrospinning parameters: voltage 14kV, propulsion speed 0.1mm min -1 , receiving distance 20cm. Electrospinning was performed in the order of mixed solution 2, mixed solution 1, and mixed solution 2 to form a sandwich structure of PAN-TPU-PAN, which was then dried and hot pressed and cut into discs with a diameter of 17mm.

[0147] 2) Under the argon protective atmosphere of the glove box, 0.5 mL of PEGMA, 1 mL of HFA and 66 μL of PEGDA were weighed and mixed evenly, and 0.281 g of LiFSI (1 M) and 0.3 g of EMIMTFSI were added thereto and stirred evenly.

[0148] 3) Add 0.1 wt % of initiator AIBN to the mixed solution and stir evenly to obtain a precursor solution.

[0149] 4) According to the button battery assembly method, the obtained precursor solution was added dropwise to the PAN-TPU-PAN fiber membrane, and the button battery was assembled. The battery was then heated at 60°C for 12 hours until the monomers were completely polymerized and a composite solid polymer electrolyte was formed inside the battery.

[0150] Example 9

[0151] The composite solid polymer electrolyte and solid-state battery of this embodiment are prepared by the following steps:

[0152] 1) 3 g TPU and 0.3 g LLZTO were dissolved in 10 g DMF to obtain a mixed solution 1. The electrospinning parameters were: voltage 17 kV, propulsion speed 0.1 mm min-1 , receiving distance 20cm. 0.5g PAN, 0.5g PVP and 0.2g LLZTO were dissolved in 10g DMF to obtain mixed solution 2. Electrospinning parameters: voltage 14kV, propulsion speed 0.1mm min -1 , receiving distance 20cm. Electrospinning was performed in the order of mixed solution 2, mixed solution 1, and mixed solution 2 to form a sandwich structure of PAN-TPU-PAN, which was then dried and hot pressed and cut into discs with a diameter of 17mm.

[0153] 2) Under the argon protective atmosphere of the glove box, 1.5 mL of PEGMA and 66 μL of PEGDA were weighed and mixed evenly, and 0.281 g of LiFSI (1 M) and 0.3 g of EMIMTFSI were added thereto and stirred evenly.

[0154] 3) Add 0.2 wt % of initiator AIBN to the mixed solution and stir evenly to obtain a precursor solution.

[0155] 4) According to the button battery assembly method, the obtained precursor solution was added dropwise to the PAN-TPU-PAN fiber membrane, and the button battery was assembled. The battery was then heated at 60°C for 12 hours until the monomers were completely polymerized and a composite solid polymer electrolyte was formed inside the battery.

[0156] Example 10

[0157] The composite solid polymer electrolyte and solid-state battery of this embodiment are prepared by the following steps:

[0158] 1) 3 g TPU and 0.3 g LLZTO were dissolved in 10 g DMF to obtain a mixed solution 1. The electrospinning parameters were: voltage 17 kV, propulsion speed 0.1 mm min -1 , receiving distance 20cm. 0.5g PAN, 0.5g PVP and 0.2g LLZTO were dissolved in 10g DMF to obtain mixed solution 2. Electrospinning parameters: voltage 14kV, propulsion speed 0.1mm min -1 , receiving distance 20cm. Electrospinning was performed in the order of mixed solution 2, mixed solution 1, and mixed solution 2 to form a sandwich structure of PAN-TPU-PAN, which was then dried and cut into discs with a diameter of 17mm.

[0159] 2) Under the argon protective atmosphere of the glove box, 1 mL of PEGMA, 0.5 mL of HFA and 33 μL of PEGDA were weighed and mixed evenly, and 0.281 g of LiFSI (1 M) and 0.3 g of EMIMTFSI were added thereto and stirred evenly.

[0160] 3) Add 0.1 wt % of initiator AIBN to the mixed solution and stir evenly to obtain a precursor solution.

[0161] 4) According to the button battery assembly method, the obtained precursor solution was added dropwise to the PAN-TPU-PAN fiber membrane, and the button battery was assembled. The battery was then heated at 60°C for 12 hours until the monomers were completely polymerized and a composite solid polymer electrolyte was formed inside the battery.

[0162] Embodiment 11

[0163] The composite solid polymer electrolyte and solid-state battery of this embodiment are prepared by the following steps:

[0164] 1) 3 g TPU and 0.3 g LLZTO were dissolved in 10 g DMF to obtain a mixed solution 1. The electrospinning parameters were: voltage 17 kV, propulsion speed 0.1 mm min -1 , receiving distance 20cm. 0.5g PAN, 0.5g PVP and 0.4g LLZTO were dissolved in 10g DMF to obtain mixed solution 2. Electrospinning parameters: voltage 14kV, propulsion speed 0.1mm min -1 , receiving distance 20cm. Electrospinning was performed in the order of mixed solution 2, mixed solution 1, and mixed solution 2 to form a sandwich structure of PAN-TPU-PAN, which was then dried and hot pressed and cut into discs with a diameter of 17mm.

[0165] 2) Under the argon protective atmosphere of the glove box, 0.5 mL of PEGMA, 1 mL of HFA and 66 μL of PEGDA were weighed and mixed evenly, and 0.281 g of LiFSI (1 M) and 0.1 g of EMIMTFSI were added thereto and stirred evenly.

[0166] 3) Add 0.1 wt % of initiator AIBN to the mixed solution and stir evenly to obtain a precursor solution.

[0167] 4) According to the button battery assembly method, the obtained precursor solution was added dropwise to the PAN-TPU-PAN fiber membrane, and the button battery was assembled. The battery was then heated at 60°C for 12 hours until the monomers were completely polymerized and a composite solid polymer electrolyte was formed inside the battery.

[0168] Example 12

[0169] The composite solid polymer electrolyte and solid-state battery of this embodiment are prepared by the following steps:

[0170] 1) 3 g TPU and 0.3 g LLZTO were dissolved in 10 g DMF to obtain a mixed solution 1. The electrospinning parameters were: voltage 17 kV, propulsion speed 0.1 mm min-1 , receiving distance 20cm. 0.5g PAN, 0.5g PVP and 0.2g LLZTO were dissolved in 10g DMF to obtain mixed solution 2. Electrospinning parameters: voltage 14kV, propulsion speed 0.1mm min -1 , receiving distance 20cm. Electrospinning was performed in the order of mixed solution 2, mixed solution 1, and mixed solution 2 to form a sandwich structure of PAN-TPU-PAN, which was then dried and hot pressed and cut into discs with a diameter of 17mm.

[0171] 2) Under the argon protective atmosphere of the glove box, 1 mL of PEGMA, 0.5 mL of HFA and 66 μL of PEGDA were weighed and mixed evenly, and 0.843 g of LiFSI (3 M) and 0.3 g of EMIMTFSI were added thereto and stirred evenly.

[0172] 3) Add 0.1 wt % of initiator AIBN to the mixed solution and stir evenly to obtain a precursor solution.

[0173] 4) According to the button battery assembly method, the obtained precursor solution was added dropwise to the PAN-TPU-PAN fiber membrane, and the button battery was assembled. The battery was then heated at 60°C for 12 hours until the monomers were completely polymerized and a composite solid polymer electrolyte was formed inside the battery.

[0174] Example 13

[0175] The composite solid polymer electrolyte and solid-state battery of this embodiment are prepared by the following steps:

[0176] 1) 3 g TPU and 0.3 g LLZTO were dissolved in 10 g DMF. The electrospinning parameters were: voltage 18 kV, propulsion speed 0.1 mm min -1 , receiving distance 20cm. Electrospinning into fiber membrane, then drying and cutting into discs with a diameter of 17mm.

[0177] 2) Under the argon protective atmosphere of the glove box, 1.5 mL of PEGMEMA and 66 μL of PEGDMA were weighed and mixed evenly, and 0.281 g of LiFSI (1 M) and 0.3 g of EMIMTFSI were added thereto and stirred evenly.

[0178] 3) Add 0.1 wt % of initiator AIBN to the mixed solution and stir evenly to obtain a precursor solution.

[0179] 4) According to the button battery assembly method, the obtained precursor solution is added dropwise to the TPU fiber membrane, and the button battery is assembled. The battery is then heated at 60°C for 6 hours until the monomer is completely polymerized to form a composite solid polymer electrolyte inside the battery.

[0180] Embodiment 14

[0181] The composite solid polymer electrolyte and solid-state battery of this embodiment are prepared by the following steps:

[0182] 1) 3 g TPU and 0.3 g LLZTO were dissolved in 10 g DMF to obtain a mixed solution 1. The electrospinning parameters were: voltage 17 kV, propulsion speed 0.1 mm min -1 , receiving distance 20cm. 0.5g PAN, 0.5g PVP and 0.2g LLZTO were dissolved in 10g DMF to obtain mixed solution 2. Electrospinning parameters: voltage 14kV, propulsion speed 0.1mm min -1 , receiving distance 20cm. Electrospinning was performed in the order of mixed solution 2, mixed solution 1, and mixed solution 2 to form a sandwich structure of PAN-TPU-PAN, which was then dried and hot pressed and cut into discs with a diameter of 17mm.

[0183] 2) Under the argon protective atmosphere of the glove box, 1 mL of PEGMEMA, 0.5 mL of HFMA and 66 μL of PEGDA were weighed and mixed evenly, and 0.281 g of LiFSI (1 M) and 0.3 g of EMIMTFSI were added thereto and stirred evenly.

[0184] 3) Add 0.1 wt % of initiator AIBN to the mixed solution and stir evenly to obtain a precursor solution.

[0185] 4) According to the button battery assembly method, the obtained precursor solution was added dropwise to the PAN-TPU-PAN fiber membrane, and the button battery was assembled. The battery was then heated at 80°C for 6 hours until the monomers were completely polymerized to form a composite solid polymer electrolyte inside the battery.

[0186] Embodiment 15

[0187] The composite solid polymer electrolyte and solid-state battery of this embodiment are prepared by the following steps:

[0188] 1) 3 g TPU and 0.3 g LLZTO were dissolved in 10 g DMF to obtain a mixed solution 1. The electrospinning parameters were: voltage 17 kV, propulsion speed 0.1 mm min -1 , receiving distance 20cm. 0.5g PAN, 0.5g PVP and 0.2g LLZTO were dissolved in 10g DMF to obtain mixed solution 2. Electrospinning parameters: voltage 14kV, propulsion speed 0.1mm min -1, receiving distance 20cm. Electrospinning was performed in the order of mixed solution 2, mixed solution 1, and mixed solution 2 to form a sandwich structure of PAN-TPU-PAN, which was then dried and hot pressed and cut into discs with a diameter of 17mm.

[0189] 2) Under the argon protective atmosphere of the glove box, 1 mL of PEGMEMA and 0.5 mL of HFMA were weighed and mixed evenly, and 0.281 g of LiFSI (1 M) and 0.3 g of EMIMTFSI were added thereto and stirred evenly.

[0190] 3) Add 0.1 wt % of initiator AIBN to the mixed solution and stir evenly to obtain a precursor solution.

[0191] 4) According to the button battery assembly method, the obtained precursor solution was added dropwise to the PAN-TPU-PAN fiber membrane, and the button battery was assembled. The battery was then heated at 80°C for 6 hours until the monomers were completely polymerized to form a composite solid polymer electrolyte inside the battery.

[0192] The inventors continued to conduct performance tests on the fiber self-supporting membranes prepared in Examples 2-15, including rebound performance test, mechanical property test, thermogravimetric analysis, impedance test after the fiber self-supporting membrane and polymer electrolyte are composited, antioxidant test, compatibility test, and cycle performance test. The test methods and test conditions are the same as in Example 1. The results are shown in Table 1.

[0193] Table 1

[0194]

[0195]

[0196] The results in Table 1 show that when the rebound performance test and the mechanical property test are the same as those in Example 1, when TPU is not added (Example 2), the mechanical properties of the PAN electrospun fiber membrane are poor and can only be stretched to 20% of the original length (such as Fig.11 As shown in the figure, the tensile properties are poor and there is no rebound performance, which means that the fiber membrane prepared by PAN alone is difficult to adapt to the volume changes produced during the charge and discharge process during the battery cycle.

[0197] Under the same test conditions as in Example 1, the room temperature ionic conductivity of the composite solid polymer electrolyte prepared in Example 3 was 1.68×10 -5 S cm -1 (like Fig.12As shown in Figure 2, its ionic conductivity is low and it is difficult to use it as a solid electrolyte in batteries. The low ionic conductivity indicates that methyl methacrylate (MMA) has a poor ability to conduct lithium ions. There are fewer polar groups on its polymer chain, and the chain segments move slowly, which is not conducive to the movement of lithium ions.

[0198] In Example 4, the room temperature ionic conductivity of the prepared composite solid polymer electrolyte is 2.2×10 -4 S cm -1 , its ionic conductivity is low. The decrease in ionic conductivity is due to the lack of polymer A1 in the system, which lacks polymer segments that conduct lithium ions. In Example 9, the room temperature ionic conductivity of the prepared composite solid polymer electrolyte is 3.21×10 -4 S cm -1 , its ionic conductivity is low, and the electrochemical window is also reduced to 4.5V. This is because the polymer network lacks polymer A2. Polymer A2 contains fluorine atoms, which can promote the dissociation of lithium salts on the one hand, and increase the electrochemical window of the polymer on the other hand. In Example 15, the room temperature ionic conductivity of the prepared composite solid polymer electrolyte is 6.56×10 -4 S cm -1 , there is a lack of polymer B in the system, the degree of polymerization is low, and it still has fluidity after polymerization, making it difficult to be used as a solid electrolyte.

[0199] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a composite solid polymer electrolyte, characterized in that: The composite solid polymer electrolyte comprises an acrylic polymer, a composite fiber self-supporting film, a lithium salt, and an ion solution. in, The composite fiber self-supporting membrane comprises a polymer matrix and lithium-rich garnet inorganic particles. The polymer matrix is ​​at least one of polyurethane and polyacrylonitrile, polyvinyl pyrrolidone, polyvinylidene fluoride-hexafluoropropylene, and polyvinylidene fluoride, and the three-dimensional fiber mesh is formed by electrospinning technology, and the lithium-rich garnet inorganic particles are attached to the surface of the three-dimensional fiber mesh; The acrylic polymer is polymerized by polymer A1 containing ether oxygen bonds, polymer A2 containing fluorine groups and polymer B having two C=C double bonds; The preparation method comprises: S1, taking compound a and compound b, and independently dissolving them with lithium-rich garnet inorganic particles in a solvent to obtain a mixed solution 1 without compound b and a mixed solution 2 without compound a, respectively; S2, electrospinning the mixed solution 2, and then continuing to electrospin the mixed solution 1 on the obtained spinning fiber membrane, and then electrospinning the mixed solution 2 again on this basis to obtain a fiber self-supporting membrane; S3, mixing polymer A1, polymer A2, polymer B, lithium salt and ion solution to obtain mixed solution 3; S4, adding an initiator to the mixed solution 3 to obtain a precursor solution; S5, dropping the precursor solution into the fiber self-supporting film, assembling it using the button battery assembly method to obtain an assembled button battery; S6, promoting monomer polymerization of the button battery in a heating environment to obtain the composite solid polymer electrolyte, in, The compound a is polyurethane, and the compound b includes at least one of polyacrylonitrile, polyvinyl pyrrolidone, polyvinylidene fluoride-hexafluoropropylene, and polyvinylidene fluoride.

2. The method according to claim 1, characterized in that The lithium-rich garnet inorganic particles include at least one of lithium lanthanum zirconium oxide and lithium lanthanum zirconium tantalum oxide (LLZTO); The mass ratio of the polymer matrix to the lithium-rich garnet inorganic particles is 100:(10-50).

3. The method according to claim 1, characterized in that The polymer A1 comprises poly(ethylene glycol) methacrylate and / or polyethylene glycol methyl ether methacrylate, The polymer A2 includes at least one of 2,2,3,4,4,4-hexafluorobutyl acrylate, 2,2,3,3,4,4,4-heptafluorobutyl methacrylate, and 1H,1H,11H-perfluoroundecyl acrylate. The polymer B comprises polyethylene glycol diacrylate and / or polyethylene glycol dimethacrylate; The volume ratio of polymer A1, polymer A2 and polymer B is 10:5:0.

66.

4. The method according to claim 1, characterized in that: The lithium salt includes lithium bis(fluorosulfonyl)imide and / or lithium bis(trifluorosulfonyl)imide, and the concentration of the lithium salt is 1-3 mol / L.

5. The method according to claim 1, characterized in that The ionic solution includes at least one of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, 1-methylimidazolium trifluoromethanesulfonate, and tributyl(methyl)phosphine dimethyl phosphate; The mass ratio of the ionic solution to polymer A1 and polymer A2 is (10-50):63:

37.

6. The method according to claim 1, characterized in that In step S1, the lithium-rich garnet inorganic particles include at least one of lithium lanthanum zirconium oxide and lithium lanthanum zirconium tantalum oxide (LLZTO); The mass ratio of compound a to compound b is 3:1; In the mixed solution 1, the mass ratio of the compound a to the lithium-rich garnet inorganic particles is 10:(1-5); In the mixed solution 2, the mass ratio of the compound b to the lithium-rich garnet inorganic particles is 10:(1-5); The solvent includes at least one of DMF, DMAC and acetone.

7. The method according to claim 1, characterized in that In step S3, the polymer A1, polymer A2, and polymer B are respectively polymer A1 containing an ether oxygen bond, polymer A2 containing a fluorine group, and polymer B having two C=C double bonds; The polymer A1 comprises poly(ethylene glycol) methacrylate and / or polyethylene glycol methyl ether methacrylate, The polymer A2 includes at least one of 2,2,3,4,4,4-hexafluorobutyl acrylate, 2,2,3,3,4,4,4-heptafluorobutyl methacrylate, and 1H,1H,11H-perfluoroundecyl acrylate. The polymer B comprises polyethylene glycol diacrylate and / or polyethylene glycol dimethacrylate; The volume ratio of polymer A1, polymer A2 and polymer B is 10:5:0.66; The lithium salt includes lithium bis(fluorosulfonyl)imide and / or lithium bis(trifluorosulfonyl)imide, and the concentration of the lithium salt is 1-3 mol / L; The ionic solution includes at least one of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, 1-methylimidazolium trifluoromethanesulfonate, and tributyl(methyl)phosphine dimethyl phosphate; The mass ratio of the ionic liquid to polymer A1 and polymer A2 is (10-50):63:

37.

8. The method according to claim 1, characterized in that In step S3, the initiator includes AIBN and benzoyl peroxide; The mass percentage of the initiator in the precursor solution is (0.05-0.2) %; In step S6, the heating temperature is 55-85 degrees Celsius.

9. Use of the composite solid polymer electrolyte prepared by the method according to any one of claims 1 to 8 in preparing lithium batteries.

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