An electrospun fiber membrane with an organic-inorganic coupling Janus structure, a preparation method and applications thereof

Abstract

The application relates to an electrospun fiber membrane with an organic-inorganic coupling Janus structure, a preparation method and application thereof. The preparation method of the electrospun fiber membrane with the organic-inorganic coupling Janus structure comprises the following steps: S1, preparing an electrospun solution: the electrospun solution is prepared by mixing a first precursor liquid and a second precursor liquid, the first precursor liquid accounts for 5-10 wt%, and the second precursor liquid accounts for 90-95 wt%; S2, preparing a nanofiber membrane by electrospinning the electrospun solution, and performing vacuum drying treatment at a temperature of 35-50 DEG C for more than 12 hours to obtain the electrospun fiber membrane with the organic-inorganic coupling Janus structure. The electrospun fiber membrane has excellent performances of high ion conductivity and low interface resistance.

Description

Technical Field

[0001] This invention belongs to the field of energy storage system device materials technology, and specifically relates to an electrospun fiber membrane with an organic-inorganic coupled Janus structure, its preparation method and its application. Background Technology

[0002] Rechargeable lithium-ion batteries (LIBs) have become indispensable energy storage devices in mobile electronic devices, smart grids, and electric transportation due to their high operating voltage, long cycle life, and high specific capacity. Given that traditional batteries cannot meet the high energy storage demands and pose safety hazards, there is an urgent need to research new lithium-based rechargeable battery technologies to improve energy density and ensure high levels of safety and reliability. Lithium metal batteries (LMBs) are widely regarded as promising next-generation energy storage devices due to their excellent specific capacity and low electrochemical potential. However, lithium metal anodes are prone to reaction with liquid electrolytes, forming lithium dendrites that pierce the separator. Furthermore, liquid electrolytes are highly flammable, easily leading to fires, explosions, and other safety accidents. Therefore, with increasing emphasis on the safety performance of liquid lithium-ion batteries (LIBs), the development of more advanced lithium-ion battery energy storage technologies is urgently needed. Solid-state electrolytes are a crucial component of solid-state batteries, and due to their high stability, high safety, and wide electrochemical window, they have become an important direction for the future development of lithium-ion batteries.

[0003] Solid-state electrolytes (SSEs) can be classified into three categories: inorganic solid-state electrolytes, polymer solid-state electrolytes, and composite solid-state electrolytes. At room temperature, inorganic solid-state electrolytes possess advantages such as high thermal stability, a wide electrochemical window, and high ionic conductivity. However, in practical applications, inorganic solid-state electrolytes face numerous problems, including poor compatibility with the electrode interface, high interfacial resistance, and poor mechanical properties, leading to difficulties in processing and short lifespan. In contrast, polymer solid-state electrolytes exhibit excellent mechanical properties, ease of processing, and good electrode / electrolyte interface compatibility. Unfortunately, polymer solid-state electrolytes (SPEs) exhibit slow polymer chain movement at room temperature, resulting in lower lithium-ion conductivity; furthermore, the relatively low Young's modulus makes it difficult to suppress lithium dendrite growth on the lithium metal anode surface. In summary, these inherent problems severely hinder the practical application of inorganic and polymer solid-state electrolytes in all-solid-state lithium batteries (ASSLBs). Composite solid-state electrolytes (CSEs) combine the advantages of good interfacial compatibility, excellent mechanical properties, and high ionic conductivity of organic and inorganic electrolytes, and are considered a highly promising candidate for all-solid-state lithium batteries (ASSLBs). Furthermore, the superior mechanical properties of CSEs allow for the use of high-specific-capacity lithium metal anodes to replace traditional graphite-based anode materials, thereby increasing the battery's energy density. Summary of the Invention

[0004] The purpose of this invention is to provide an electrospun fiber membrane with an organic-inorganic coupled Janus structure. This electrospun fiber membrane has excellent properties such as high ion conductivity and low interfacial resistance. The fiber membrane itself serves as an ion transport layer, and a dense layer is constructed on its surface by casting PEO-LiTFSI. The two together form a solid electrolyte, which is suitable for use as a solid electrolyte in the construction of flexible lithium-ion battery energy storage devices.

[0005] The technical solution adopted by this invention to solve its technical problem is:

[0006] A method for preparing an electrospun fiber membrane with an organic-inorganic coupled Janus structure, the method comprising the following steps:

[0007] S1. Preparation of electrospinning solution:

[0008] The electrospinning solution is composed of a first precursor solution and a second precursor solution, with the first precursor solution accounting for 5-10 wt% and the second precursor solution accounting for 90-95 wt%.

[0009] Preparation of the first precursor fluid: 50-80 wt% polyvinyl fluoride-hexafluoropropylene copolymer (PVDF-HFP), 1-18 wt% succinic anionyl nitrile (SN), and 10-30 wt% LLZO (lithium lanthanum zirconium oxide Li7La3Zr2O) are added. 12 ) and 1-5 wt% lithium salt, dissolved in an appropriate amount of N,N-dimethylformamide (DMF), and stirred at 30-50°C for at least 12 hours to mix thoroughly; the total weight of solid solute in the first precursor liquid is 100%;

[0010] Preparation of the second precursor solution: 5-10 wt% lithium salt, 20-30 wt% high-viscosity polymer, and 50-60 wt% acetonitrile were stirred at room temperature for more than 12 hours to homogenize the solution; the total weight of the second precursor solution was 100%.

[0011] S2. Prepare nanofiber membranes by electrospinning the electrospinning solution, and vacuum dry at 35-50℃ for more than 12 hours to obtain the electrospinned fiber membrane with the organic-inorganic coupled Janus structure.

[0012] This invention utilizes electrospinning technology, which offers significant advantages in the preparation of organic-inorganic composite solid electrolytes. This technology boasts lower production costs, contributing to reduced solid electrolyte membrane fabrication costs and improved overall production efficiency. Furthermore, electrospinning enables the production of homogeneous nanofibers, ensuring stable and reliable performance of energy storage devices. This method offers a simple and rapid fabrication process, suitable for preparing solid electrolyte membranes in flexible wearable energy storage devices.

[0013] This invention uses a PVDF-HFP polymer with -CF- groups as the main material. Its advantages include strong electron absorption capacity, excellent thermal stability, and good dielectric constant, making it a promising candidate for use in lithium-ion batteries. The PVDF-HFP copolymer consists of a crystalline PVDF phase and an amorphous HFP phase. The PVDF phase has a high dielectric constant, which can effectively dissociate lithium salts. Furthermore, at room temperature, PVDF exhibits high crystallinity, while HFP can lower the polymer's glass transition temperature and increase the amorphous region, thereby significantly improving the mechanical properties of the composite electrolyte membrane and its ionic conductivity at room temperature.

[0014] In this invention, succinic anhydride, possessing nonionic and highly polar properties, is used as an electrolyte additive. Due to its high boiling point of 267°C and extremely low vapor pressure, it effectively improves the thermal stability of the solid electrolyte. Furthermore, the high dielectric constant of succinic anhydride effectively dissociates lithium salts in the solid electrolyte, providing more migratable lithium ions. Succinic anhydride is also used as a plasticizer to improve the ionic conductivity and polarity of the solid polymer electrolyte. However, the addition of lithium salts significantly lowers the melting point of succinic anhydride, causing the succinic anhydride-containing solid polymer electrolyte to exhibit excessive plasticity or a liquid-like behavior at room temperature, thereby reducing the mechanical strength of the solid polymer electrolyte. This invention employs an electrospinning method and adds LLZO inorganic rigid particles to the spinning solution. This invention effectively solves the problem of excessive plasticity or a liquid-like behavior in succinic anhydride-containing solid polymer electrolytes at room temperature, effectively improving the strength and thermal stability of the solid electrolyte membrane while also increasing its ionic conductivity.

[0015] The addition of a very small amount of high-viscosity polymer in this invention increases the viscosity of the electrospinning solution, significantly optimizing the orientation of the prepared electrospun nanofibers and providing a continuous pathway for lithium-ion transport in solid electrolytes. LLZO forms a beaded coating layer on the surface of the fibrous polymer, with LLZO particles tightly wrapped around and interconnected with the polymer nanofibers, providing more options for lithium-ion channel formation. More importantly, the three-dimensional network structure ion channel layer constructed using electrospinning technology helps improve lithium-ion transport efficiency. The microstructure of the three-dimensional network channel layer prepared by electrospinning involves interwoven composite nanofibers forming a three-dimensional network structure as a framework support, which is tightly bonded to the dense PEO-lithium salt layer cast on its surface through strong intermolecular hydrogen bonds. The one-dimensional nanofiber structure significantly increases the contact area between the fiber network and the PEO-lithium salt, promoting sufficient contact between the two and greatly improving the mechanical properties of the electrolyte membrane.

[0016] Furthermore, the nanofibers prepared in this invention exhibit numerous physical cross-linking points. These cross-linking points not only ensure the continuity of the lithium-ion channels, but the intermolecular hydrogen bonding effect between PVDF-HFP and PEO also disrupts the ordered arrangement of PEO segments in the dense PEO / lithium salt layer cast on the fiber membrane, effectively reducing the crystallinity of the PEO polymer. This enhances the lithium-ion transport efficiency in the electrolyte, enabling uniform lithium-ion transport. Simultaneously, the dense PEO / lithium salt layer cast on the channel layer surface not only suppresses side reactions caused by direct contact between free SN and the lithium metal anode, but also avoids the degradation of Ti due to direct contact between LLZO and the lithium metal anode. 4+ Will be restored to low-valence Ti 3+ This leads to a higher concentration of electronically conductive charge carriers. It also causes the formation of an interface where ions and electrons mix, further contributing to internal short circuits in solid-state batteries. This effectively suppresses lithium dendrite formation and improves the interfacial stability between lithium metal and the solid electrolyte.

[0017] Preferably, the molecular weight of the PVDF-HFP in the first precursor fluid is 6000-14000. More preferably, the LLZO content in the first precursor fluid is 30 wt%.

[0018] Preferably, in the second precursor fluid, the high-viscosity polymer is selected from one or more of polyethylene oxide (PEO), polyvinylpyrrolidone (PVP), waterborne polyurethane (PU), polyacrylamide (CPAM), hydrolyzed polyacrylamide (HPAM), carboxymethyl starch, starch acetate, hydroxymethyl cellulose, carboxymethyl cellulose (CMC), guar gum, gelatin, or sodium alginate.

[0019] Preferably, the high-viscosity polymer is PEO with a molecular weight of 6000-14000.

[0020] Preferably, in the first precursor fluid and the second precursor fluid, the lithium salt is independently selected from one or more of lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium bis(fluorosulfonyl)imide (LiFSI), lithium di(oxalate-borate) (LiBOB), lithium di(fluorooxalate-borate) (LiDFOB), lithium di(fluorophosphate) (LiPO2F), or lithium bis(trifluoromethanesulfonyl)imide (LiTFSI).

[0021] Preferably, the first precursor liquid and the second precursor liquid in S1 are mixed in proportion and stirred at a temperature of 30±10℃ for more than 6 hours to obtain an electrospinning liquid after being mixed evenly.

[0022] Preferably, during electrospinning in S2, the distance between the drum and the needle is set to 10-15 cm, the feed speed is 0.5-1.5 mL / h, the power supply voltage is set to 5-30 kV, the humidity is controlled below 30%, and the temperature is controlled between 15 ℃ and 35 ℃.

[0023] The distance between the drum and the needle is set to 10-15 cm. Within this range, good fiber stretching and formation are achieved, which is beneficial to the uniformity and quality of the nanofiber membrane. The feed rate is set to 0.5-1.5 mL / h. Within this speed range, the fiber stretching and spray uniformity can be controlled, which is beneficial to obtaining the ideal nanofiber membrane thickness and structure. The power supply voltage is set to 5-30 kV. Voltage within this range can affect the formation of nanofiber spray, helping to control the formation and arrangement of fibers, and thus affecting the performance of the fiber membrane. Humidity is controlled below 30%. Low humidity helps the fibers dry quickly and avoids interference from moisture in fiber formation, which is beneficial to improving the quality and stability of the nanofiber membrane. The temperature is controlled between 15℃ and 35℃. A suitable temperature helps maintain the stability of fiber spraying and fiber membrane formation, and is also beneficial to subsequent drying processes.

[0024] An electrospun fiber membrane with an organic-inorganic coupled Janus structure obtained by the preparation method described in this invention.

[0025] The application of an electrospun fiber membrane with an organic-inorganic coupled Janus structure as described in this invention as a solid electrolyte in batteries.

[0026] Application of an electrospun fiber membrane with an organic-inorganic coupled Janus structure as described in this invention in the fabrication of flexible solid-state lithium batteries.

[0027] In the above applications, the electrospun fiber membrane of the present invention serves as an ion transport layer, and a dense layer is constructed on its surface by casting PEO-LiTFSI. The two together form a solid electrolyte with better performance.

[0028] Preferably, the positive electrode active material is selected from one or more of lithium cobalt oxide (LiCoO2), lithium iron phosphate (LiFePO4), lithium manganese oxide (LiMn2O4), lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2), lithium aluminate (LiAlO2), lithium vanadate (LiV2O5), lithium titanate (LiTiO2), nickel cobalt manganese ternary materials (NMC, Li(NiCoMn)O2), and cobalt tin oxide (CoSn).

[0029] Preferably, in the preparation of flexible solid-state lithium batteries, Super P (conductive carbon black) / positive electrode active material / PEO / lithium salt is dispersed in acetonitrile at a weight ratio of 1:6:2:1. This ratio ensures that the positive electrode slurry has good dispersibility and viscosity, which is beneficial for subsequent coating and drying processes. It is then uniformly coated onto carbon-coated aluminum foil, with a coating thickness controlled at 20 μm~40 μm and an areal density controlled at 1-5 mg·cm³. -2 The material was then vacuum-dried at 80°C for 24 hours. These preparation conditions ensured that the cathode material was uniformly coated on the current collector, and that the appropriate drying time and temperature optimally preserved the structure and properties of the cathode material. Furthermore, the areal density loading of the active material was 1-5 mg·cm³. -2 It can achieve high energy density and cycle stability while maintaining battery performance.

[0030] This invention utilizes electrospinning technology to prepare organic-inorganic composite solid electrolytes, offering advantages such as lower production costs, a simple and rapid preparation process, and homogenization of nanofibers. This technology uses PVDF-HFP polymers as the main material, combined with succinic acid as an electrolyte additive, and incorporates LLZO inorganic rigid particles into the spinning solution to address the problem of excessive plasticity or liquid-like behavior of solid polymer electrolytes at room temperature. Simultaneously, the three-dimensional network channel layer prepared by electrospinning helps improve lithium-ion transport efficiency. It has the following characteristics:

[0031] (1) Organic-inorganic composite solid electrolytes are prepared by electrospinning technology to reduce production costs and improve preparation efficiency;

[0032] (2) Using PVDF-HFP polymer as the main material and combining it with succinic acid as an electrolyte additive improves the thermal stability and ionic conductivity of the solid polymer electrolyte;

[0033] (3) Adding LLZO inorganic rigid particles solves the problem of excessive plasticity or liquid behavior of solid polymer electrolytes at room temperature, and improves the strength and thermal stability of solid electrolyte membranes;

[0034] (4) The three-dimensional network structure channel layer prepared by electrospinning helps to improve the lithium ion transport efficiency and at the same time improves the mechanical properties of the electrolyte membrane.

[0035] (5) In this invention, due to the addition of high viscosity polymer in the spinning solution, the nanofiber membrane prepared by this invention has a high degree of orientation, which is beneficial to the transport of lithium ions when applied to solid-state lithium batteries.

[0036] Therefore, the present invention prepares an organic-inorganic composite solid electrolyte with excellent performance, which can be used to prepare flexible wearable energy storage devices. Attached Figure Description

[0037] Figure 1 These are XRD comparison spectra of LLZO, electrospun fiber membrane with LLZO (PHS), and electrospun fiber membrane without LLZO in Example 1.

[0038] Figure 2 These are high-magnification SEM images (left) and (right) of the nanofiber membrane obtained in Example 1.

[0039] Figure 3 This is a SEM image of the electrospun fiber membrane without the addition of high-viscosity electrospun fiber membrane in step 5 of Example 2.

[0040] Figure 4 In step 4 of Example 3, the first precursor liquid and the second precursor liquid are not distinguished, and the components are directly mixed to prepare the electrospinning solution, resulting in the SEM image of the spun fiber membrane.

[0041] Figure 5 These are the TGA spectra of the nanofiber membranes obtained in Example 1 (PHSL-CSE) and Comparative Example 1 (PHS-CSE).

[0042] Figure 6 These are the stress-strain curves of the PHSL-CSE solid electrolyte prepared in step three, the PHSL-CSE solid electrolyte prepared in step four, and the PEO-LiTFSI solid electrolyte prepared in step five of Example 1.

[0043] Figure 7 This is the EIS spectrum of the PHSL-CSE composite solid electrolyte obtained in Supplementary Example 6.

[0044] Figure 8The Arrhenius curves are for the PEO-LiTFSI, PHS-CSE, and PHSL-CSE composite solid electrolytes obtained in Supplementary Example 6.

[0045] Figure 9 These are the LSV curves of the PEO-LiTFSI, PHS-CSE, and PHSL-CSE composite solid electrolytes from Supplementary Example 7.

[0046] Figure 10 This is a supplementary example 8 showing the impedance change spectrum of the PHSL-CSE composite solid electrolyte in a lithium symmetric battery before and after 100 cycles.

[0047] Figure 11 This supplements the critical current density of the PEO-LiTFSI, PHS-CSE, and PHSL-CSE composite solid electrolytes in Example 8.

[0048] Figure 12 This is a supplementary example of the long-cycle curves of the PHSL-CSE composite solid electrolyte in a lithium-symmetric battery.

[0049] Figure 13 This is the rate performance curve of the soft-pack full cell obtained from Example 2.

[0050] Figure 14 The curves show the long-cycle performance of the pouch cell obtained in Example 2.

[0051] Figure 15 These are optical images showing the solid-state pouch lithium metal battery obtained in Example 2 in good working condition under flat, bent, folded, cut, and needle-punctured conditions. Detailed Implementation

[0052] The technical solution of the present invention will be further described in detail below through specific embodiments. It should be understood that the implementation of the present invention is not limited to the following embodiments, and any modifications and / or alterations made to the present invention will fall within the protection scope of the present invention.

[0053] In this invention, unless otherwise specified, all parts and percentages are by weight, and the equipment and raw materials used are commercially available or commonly used in the art. Unless otherwise specified, the methods in the following embodiments are conventional methods in the art.

[0054] Unless otherwise specified, the reagents used in the following examples can be purchased from a regular biochemical reagent store.

[0055] Super P, Chinese name: conductive carbon black, purchased from Dongguan Kelude Co., Ltd.

[0056] Example 1

[0057] A method for preparing an electrospun fiber membrane with an organic-inorganic coupled Janus structure, the specific steps of which are as follows:

[0058] Step 1: Prepare the first precursor solution. Combine 0.24g of polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP), 0.08g of succinate (SN, 99%), and 0.08g of Li7La3Zr2O. 12 (LLZO) and 0.08 g LiTFSI were dissolved in 5 mL of N,N-dimethylformamide (DMF), and the solution was stirred at 30 °C for at least 12 hours until it was homogeneous.

[0059] Step 2: Prepare the second precursor solution. Mix 0.015g LiTFSI, 0.05g polyethylene oxide (PEO), and 1mL acetonitrile (ACN) and stir at room temperature for 12 hours or longer to homogenize the solution.

[0060] Step 3: Mix the second precursor liquid and the first precursor liquid obtained above to prepare an electrospinning solution, and stir at 30°C for at least 6 hours until the mixture is fully mixed to obtain an electrospinning solution.

[0061] Step 4: Electrospinning was performed using the prepared electrospinning solution. The electrospinning parameters were set as follows: the distance between the spinning drum and the needle was 13 cm, the feed rate was 0.7 mL / h, the voltage was set to 12 kV, the humidity was controlled below 30%, and the temperature was maintained between 25°C and 35°C. The obtained fiber membrane was peeled off from the tin foil and transferred to a vacuum drying oven at 50°C for at least 12 hours to ensure complete drying. The nanofiber membrane prepared in this step was named PHSL.

[0062] Step 5: Preparation of LLZO-free electrospun fiber membrane (control group). Prepare the first precursor solution. Dissolve 0.24 g of polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP), 0.08 g of nitrile butadiene nitrile (SN, 99%), and 0.08 g of LiTFSI in 5 mL of N,N-dimethylformamide (DMF). Stir the solution at 30°C for at least 12 hours until homogeneous. Add the second precursor solution obtained in Step 2 to the first precursor solution to prepare the electrospinning solution, and stir at 30°C for at least 6 hours until the mixture is fully incorporated. Perform electrospinning using the prepared electrospinning solution, following the same process as in Step 4. Name the final nanofiber membrane PHS.

[0063] Supplementary Example 1: Crystallinity and thermal stability tests of PHSL electrospun fiber membranes with and without LLZO.

[0064] Crystallinity test: Figure 1 The XRD patterns of PHS without LLZO and PHSL with LLZO are shown. According to the XRD characterization results, the characteristic peaks of LLZO did not change significantly after its addition to the polymer, indicating that the LLZO inorganic filler can maintain structural integrity after being added to the polymer. Compared with the PHS electrospun nanofiber membrane without LLZO, the diffraction peaks of the PHSL nanofiber membrane with LLZO broadened, indicating a decrease in the crystallinity of PVDF-HFP. This is because the addition of LLZO enhances the effective interaction between the polymer chains and ion species, thereby promoting the recrystallization of PVDF-HFP and forming more amorphous regions. The increase in amorphous regions is more conducive to the transfer rate of lithium ions in the solid electrolyte, improving the electrochemical performance of the electrolyte membrane. Thermal stability test: as shown. Figure 5 As shown, in the temperature range of room temperature to 100℃, the thermal stability of PHS and PHSL nanofiber membranes mainly involves the evaporation of residual solvent and trace amounts of moisture absorbed by the nanofiber membrane from the air. The nanofiber membrane without LLZO showed a significant decrease at 315.8℃, while the nanofiber membrane prepared with LLZO showed a significant change at 343.9℃. By adding LLZO during the preparation of the nanofiber membrane, the thermal stability of the PHSL-CSE composite solid electrolyte was significantly improved.

[0065] Supplementary Example 2: Surface morphology characterization of PHSL electrospun fiber membrane with added LLZO.

[0066] Figure 2 These are, respectively, high-magnification SEM images (left) and (right) of the PHSL nanofiber membrane obtained in Example 1. Figure 2 As can be seen in the left image, there are many physical cross-linking points between the nanofibers. These cross-linking points ensure the continuity of lithium-ion channels, thereby improving the transport efficiency of lithium ions in the electrolyte and enabling lithium ions to be transported uniformly in the electrolyte. Figure 2 As shown in the right image, LLZO forms a beaded coating layer on the surface of the fibrous polymer. The LLZO particles are tightly wrapped around the polymer nanofibers and interconnected, which provides more options for the formation of lithium-ion channels. At the same time, the one-dimensional structure of the nanofibers significantly increases the contact area between the ion channel layer formed by the fiber network and the dense layer, promoting full contact between the two and greatly improving the mechanical properties of the electrolyte membrane.

[0067] Example 2

[0068] A method for preparing an electrospun fiber membrane with an organic-inorganic coupled Janus structure, the specific steps of which are as follows:

[0069] Step 1: Prepare the first precursor solution. Combine 0.24g of polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP), 0.08g of succinate (SN, 99%), and 0.08g of Li7La3Zr2O. 12 (LLZO) and 0.08 g of lithium hexafluorophosphate (LiPF6) were dissolved in 5 mL of N,N-dimethylformamide (DMF), and the solution was stirred at 30 °C for at least 12 hours until it was homogeneous.

[0070] Step 2: Prepare the second precursor solution. Mix 0.015 g LiTFSI, 0.05 g polyvinylpyrrolidone (PVP), and 1 mL acetonitrile (ACN) and stir at room temperature for 12 hours or longer to homogenize the solution.

[0071] Step 3: Mix the second precursor liquid and the first precursor liquid obtained above to prepare an electrospinning solution, and stir at 30°C for at least 6 hours until the mixture is fully mixed to obtain an electrospinning solution.

[0072] Step 4: Electrospinning was performed using the prepared electrospinning solution. The electrospinning parameters were set as follows: the distance between the spinning drum and the needle was 13 cm, the feed rate was 0.7 mL / h, the voltage was set to 12 kV, the humidity was controlled below 30%, and the temperature was maintained between 25°C and 35°C. The obtained fiber membrane was peeled off from the tin foil and transferred to a vacuum drying oven at 50°C for at least 12 hours to ensure complete drying. The nanofiber membrane prepared in this step was named PHSL, and the SEM image is shown below. Figure 2 (Left).

[0073] Step 5: Preparation of electrospun fiber membrane (control group without high-viscosity polymer). Prepare the first precursor solution. Add 0.24g of polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP) and 0.08g of Li7La3Zr2O 12 (Ga-LLZO) and 0.08 g of lithium hexafluorophosphate (LiPF6) were dissolved in 5 mL of N,N-dimethylformamide (DMF), and the solution was stirred at 30 °C for at least 12 hours until homogeneous. This yielded the electrospinning solution. Electrospinning was performed using the prepared electrospinning solution, following the same process as in step 4. The resulting SEM microstructure is shown below. Figure 3 .

[0074] Supplementary Example 3: SEM characterization of electrospun fiber membranes with added high-viscosity polymers and those without added high-viscosity electrospun fiber membranes.

[0075] SEM images of electrospun fiber membranes with added high-viscosity polymers are shown below. Figure 2 As shown on the left, the SEM image of a highly oriented electrospun fiber membrane without the addition of high-viscosity electrospun fiber is as follows. Figure 3 As shown, the resulting fiber structure is disordered and lacks orientation. Furthermore, the fiber surface lacks LLZO inorganic ions, which is detrimental to ion transport. This indicates that the addition of a very small amount of high-viscosity polymer increases the viscosity of the electrospinning solution, greatly optimizing the orientation of the prepared electrospun nanofibers and providing a continuous pathway for lithium ion transport in solid electrolytes.

[0076] Example 3

[0077] A method for preparing an electrospun fiber membrane with an organic-inorganic coupled Janus structure, the specific steps of which are as follows:

[0078] Step 1: Prepare the first precursor solution. Combine 0.24g of polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP), 0.08g of succinate (SN, 99%), and 0.08g of Li7La3Zr2O. 12 (LLZO) and 0.08 g LiTFSI were dissolved in 5 mL of N,N-dimethylformamide (DMF), and the solution was stirred at 30 °C for at least 12 hours until it was homogeneous.

[0079] Step 2: Prepare the second precursor solution. Mix 0.015g LiTFSI, 0.05g polyethylene oxide (PEO), and 1mL acetonitrile (ACN) and stir at room temperature for 12 hours or longer to homogenize the solution.

[0080] Step 3: Mix the second precursor liquid and the first precursor liquid obtained above to prepare an electrospinning solution, and stir at 30°C for at least 6 hours until the mixture is fully mixed to obtain an electrospinning solution.

[0081] Step 4: Electrospinning was performed using the prepared electrospinning solution. The electrospinning parameters were set as follows: the distance between the spinning drum and the needle was 13 cm, the feed rate was 0.7 mL / h, the voltage was set to 12 kV, the humidity was controlled below 30%, and the temperature was maintained between 25°C and 35°C. The obtained fiber membrane was peeled off from the tin foil and transferred to a vacuum drying oven at 50°C for at least 12 hours to ensure complete drying. The nanofiber membrane prepared in this step was named PHSL.

[0082] Step 4: Without distinguishing between the first and second precursor fluids, directly mix the components to prepare the electrospinning solution. The specific formulation is the same as in Example 1, and the spinning process is the same as in Step 4. The resulting spun fiber membrane is as follows: Figure 4 As shown.

[0083] Supplementary Example 4: Comparison of fiber membranes obtained from spinning solutions that do not distinguish between the first and second precursor fluids and those that do distinguish between the first and second precursor fluids.

[0084] SEM images of fiber membranes obtained by distinguishing between the first and second precursor fluids in the spinning solution are shown below. Figure 2 As shown in (left), the electrospun fiber membrane exhibits high orientation and has a noticeably uneven surface with LLZO particles attached. The SEM image of the fiber membrane obtained from the spinning solution, which does not distinguish between the first and second precursor solutions, is shown below. Figure 5 As shown, the resulting fiber structure is disordered, lacks orientation, and has no LLZO particles on the surface, a structure unfavorable for ion transport. This indicates that distinguishing between the first and second precursor liquids can improve the polymer's fluidity in solution, contributing to the formation of a more uniform spinning solution. This helps reduce fiber inhomogeneity during spinning, improving fiber quality and uniformity. Furthermore, the high-viscosity polymer in the spinning solution can increase the viscosity and surface tension of the spinning solution by forming an alternating structure with PVDF-HFP, improving the stability of the spinning solution and preventing fiber breakage or spraying during spinning. This facilitates the orientation of electrospun nanofibers, providing a continuous pathway for lithium ion transport in solid electrolytes.

[0085] Example 4

[0086] A method for preparing an electrospun fiber membrane with an organic-inorganic coupled Janus structure, the specific steps of which are as follows:

[0087] Step 1: Prepare the first precursor solution. Combine 0.24g of polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP), 0.08g of succinate trans isomer (SN, 99%), and 0.08g of Ga-doped Li7La3Zr2O. 12 (Ga-LLZO) and 0.08 g of lithium difluorosulfonyl imide (LiFSI) were dissolved in 5 mL of N,N-dimethylformamide (DMF), and the solution was stirred at 30 °C for at least 12 hours until it was homogeneous.

[0088] Step 2: Prepare the second precursor solution. Mix 0.015 g lithium bis(fluorosulfonyl)imide (LiFSI), 0.05 g polyacrylamide (CPAM), and 1 mL acetonitrile (ACN), and stir at room temperature for 12 hours or longer to homogenize the solution.

[0089] Step 3: Mix the second precursor liquid and the first precursor liquid obtained above to prepare an electrospinning solution, and stir at 30°C for at least 6 hours until the mixture is fully mixed to obtain an electrospinning solution.

[0090] Step 4: Electrospinning is performed using the prepared electrospinning solution. The electrospinning parameters are set as follows: the distance between the spinning drum and the needle is 13 cm, the feed rate is 0.7 mL / h, the voltage is set to 12 kV, the humidity is controlled below 30%, and the temperature is maintained between 25°C and 35°C. The resulting fiber film is peeled off from the tin foil and transferred to a vacuum drying oven at 50°C for at least 12 hours to ensure complete drying.

[0091] Application Example 1: A method for preparing a composite solid electrolyte for lithium metal batteries

[0092] Step 1: Prepare the raw materials for the solid electrolyte dense layer. Accurately weigh 0.8 g LiTFSI and 2.45 g PEO, and mix them with 50 mL acetonitrile. Then stir the mixture at room temperature for at least 12 hours to ensure the homogeneity of the solution.

[0093] Step 2: Cut the electrospun fiber membrane obtained in Example 1. Cut the obtained electrospun fiber membrane PHSL into 10 cm squares and place them flat on a polytetrafluoroethylene plate.

[0094] Step 3: Casting the prepared PEO / LiTFSI solution. 5 mL of the PEO / LiTFSI solution was uniformly cast onto the fiber membrane PHS and allowed to air dry completely at room temperature in a well-ventilated area. Finally, the sample was transferred to a vacuum oven at 50°C for at least 12 hours of drying to obtain the composite solid electrolyte membrane, which was named PHSL-CSE.

[0095] Step 4: Preparation of PHSL-CSE solid electrolyte (solid electrolyte control group prepared by fiber membrane without LLZO): The fiber membrane PHS obtained in Step 5 of Example 1 was used to prepare a solid electrolyte membrane according to Steps 1 to 3 of the application example. Finally, a composite solid electrolyte membrane was obtained and named PHS-CSE.

[0096] Step 5: Preparation of PEO-LiTFSI polymer solid electrolyte (control group): Accurately weigh 0.08 g LiTFSI and 0.245 g PEO, and mix them with 5 mL acetonitrile. Stir the mixture at room temperature for at least 12 hours. Cast the prepared PEO / LiTFSI solution onto a polytetrafluoroethylene (PTFE) sheet in a square area of ​​approximately 10 cm × 10 cm, and allow it to air dry completely at room temperature in a well-ventilated area. Transfer the sample to a vacuum oven at 50 °C for at least 12 hours of drying to obtain the final PEO-LiTFSI polymer solid electrolyte membrane.

[0097] Supplementary Example 5: Stress-strain curve analysis of PHSL-CSE solid electrolyte, PHS-CSE solid electrolyte and PEO-LiTFSI polymer solid electrolyte membranes.

[0098] like Figure 6 As shown, in the tensile test, the stress of the PEO / LiTFSI system was only 0.81 MPa, while the stresses of the PHS-CSE solid electrolyte and PHSL-CSE solid electrolyte were 2.72 and 4.24 MPa, respectively. The PHSL-CSE solid electrolyte, due to the continuous structure of the three-dimensional network transport layer and the addition of LLZO rigid nanoparticles, provides a higher modulus. This indicates that LLZO inorganic particles can effectively enhance the mechanical properties of the material, improve the strength and stiffness of the membrane, thereby leading to an increase in stress and Young's modulus. Furthermore, the cross-linking structure formed between organic molecules and inorganic particles enhances the three-dimensional network of the membrane, improving the overall structural stability and mechanical properties. The high-stress and high-Young's modulus membrane can improve the mechanical strength of the solid electrolyte, reduce mechanical fatigue during cycling, and extend battery life. Simultaneously, in solid-state lithium metal battery systems, it can suppress lithium dendrite growth. The high mechanical strength of the electrolyte membrane helps suppress the formation of lithium dendrites during cycling, reducing the risk of dendrite penetration and improving the safety of solid-state lithium metal batteries.

[0099] Application Example 2

[0100] A method for preparing a flexible solid-state lithium metal battery and its application, comprising the following steps:

[0101] Step 1: Prepare the cathode material.

[0102] The lithium iron phosphate (LiFePO4) positive electrode active material was vacuum dried at 100℃ to remove moisture. Super P (conductive carbon black) / LiFePO4 / PEO / LiTFSI were ground and dispersed in acetonitrile at a weight ratio of 1:6:2:1 to form a uniform slurry. The slurry was coated onto an aluminum foil current collector and vacuum dried at 80℃ for 24 hours. The active material loading of the positive electrode material was approximately 2 mg·cm³. -2 .

[0103] Step 2: Assemble flexible solid-state lithium metal batteries using PHSL-CSE solid electrolyte membranes.

[0104] The positive electrode material and lithium metal sheet prepared in step 1 were used as the positive and negative electrodes, respectively. Nickel metal was used as the negative electrode tab, and aluminum metal strips as the positive electrode tab. The PHSL-CSE composite solid electrolyte membrane prepared in step 3 of Application Example 1 was used as the electrolyte for assembly, and aluminum-plastic film was used as the encapsulation material. The dried positive and negative electrodes were cut into 6 cm × 6 cm individual pieces according to design requirements, and the electrolyte membrane was also cut into 6 cm × 6 cm individual pieces. Then, the electrodes were stacked in the order of positive electrode-solid electrolyte-negative electrode, and the positive and negative electrode tabs were fixed to the electrode pieces with conductive copper tape. Vacuum sealing or needle sealing was used to ensure that the positive and negative electrodes did not come into contact with air.

[0105] Step 3: Assemble flexible solid-state lithium metal batteries using PHSL-CSE solid electrolyte membranes.

[0106] Using the PHS-CSE composite solid electrolyte membrane prepared in step 4 of Application Example 1 as the electrolyte, a flexible solid-state lithium metal battery was assembled in the manner described in step 2.

[0107] Step 4: Assemble flexible solid-state lithium metal batteries using PEO-LiTFSI solid electrolyte membranes.

[0108] Using the PEO-LiTFSI polymer solid electrolyte membrane prepared in step 5 of Application Example 1 as the electrolyte, a flexible solid-state lithium metal battery was assembled in accordance with the method in step 2.

[0109] Supplementary Example 6: Ionic Conductivity Test. To further investigate the electrochemical performance of PHSL-CSE, symmetrical cells with stainless steel blocked electrodes assembled using PHSL-CSE, PHS-CSE, and PEO / LiTFSI solid electrolytes were compared. EIS curves were tested under different temperature conditions. Calculations showed that the ionic conductivity of PHSL-CSE can reach 5.24 × 10⁻⁶ at 50℃. -4 S cm -1 (like Figure 7 As shown in the figure, the activation energies required for ion migration in different solid electrolyte systems were further calculated using the Arrhenius equation. Figure 8As shown, the activation energy of PHSL-CSE is 0.29 eV, that of PHS-CSE is 0.61 eV, and that of PEO / LiTFSI is 0.49 eV. This indicates that ions migrate more easily and require less energy in the PHSL-CSE solid electrolyte. The lower activation energy of the PHSL-CSE solid electrolyte is mainly due to the ion channels formed on the surface of the transport layer of LLZO in PHSL-CSE, which combine with the ion channels of the nanofibers themselves to form dual ion channels, broadening the lithium ion transport path and accelerating the lithium ion transfer rate. Furthermore, according to the space charge layer theory, the three-dimensional LLZO nanostructure as a filler can provide a more continuous percolation interface and higher percolation efficiency, thereby improving lithium ion conductivity.

[0110] Supplementary Example 7: Electrochemical Window Test. To further investigate the electrochemical window of PHSL-CSE, stainless steel / Li half-cells were assembled using PHSL-CSE, PHS-CSE, and PEO / LiTFSI as solid electrolytes for comparison. The LSV curves were tested at 50 °C, as shown below. Figure 9 The LSV curves show that the oxidation current of the PEO / LiTFSI solid electrolyte is close to zero below 3.53 V, but increases significantly with increasing voltage, indicating that the electrolyte membrane begins to oxidize and decompose around 3.53 V. The electrochemical window of the PHS-CSE solid electrolyte without LLZO reaches 4.5 V, while the PHSL-CSE solid electrolyte with LLZO exhibits a wide electrochemical window of up to 4.83 V. This improved electrochemical window is mainly due to the construction of the three-dimensional network transport layer and the addition of LLZO. The three-dimensional ion transport layer facing the positive electrode itself has good antioxidant properties. The superior electrochemical window indicates that the multifunctional electrolyte membrane with the Janus structure maintains good cycling stability and safety performance even at relatively high voltages. This is mainly attributed to the TFSI in LLZO and LiTFSI. - Anions bind, hindering TFSI - The anions further undergo an irreversible oxidation reaction with PEO, thereby effectively increasing the electrochemical window.

[0111] Supplementary Example 8: Electrochemical performance testing of lithium symmetric batteries.

[0112] To further investigate the stability of the lithium metal-solid electrolyte interface, a lithium-ion symmetric battery was assembled using a lithium metal sheet as the counter electrode and a series of tests were conducted. First, the Li / / Li battery containing the electrolyte was tested at current densities ranging from 0.1 to 1.1 mA cm⁻¹. -2Tests were conducted intermittently, with each half-cycle lasting 0.5 hours. The test results for the critical current density (CCD) are as follows: Figure 11 As shown, when the current density of Li|PEO / LiTFSI|Li reaches 0.3 mA cm⁻¹ -2 At this point, the polarization voltage increases sharply, and the battery short-circuits. Simultaneously, when the current density of Li|PHS-CSE|Li reaches 0.4 mA cm⁻¹... -2 At this point, a sharp drop in overpotential leads to a short circuit. However, in lithium-symmetric cells assembled with PHS-CSE solid electrolyte, the current density continues to reach 1.1 mA cm⁻¹. -2 No voltage surge occurred, indicating that the addition of LLZO enables La atoms to form complexes with N atoms in succinate, limiting the diffusion of SN at the electrode-electrolyte interface and suppressing adverse corrosion reactions between SN and Li metal surface. In addition, the dense PEO / LiTFSI layer coated on the outside of the channel layer exhibits good compatibility with lithium metal and also acts as a barrier between SN and Li metal, preventing side reactions and enhancing the tolerance of the solid electrolyte membrane.

[0113] In addition, according to Figure 10 It can be seen that the lithium-symmetric battery based on the PHSL-CSE solid electrolyte maintains an interfacial resistance of 295 Ω before cycling, and the Li | PHSL-CSE | Li interfacial resistance drops to 221 Ω after 100 cycles. The PHSL-CSE solid electrolyte exhibits a lower interfacial resistance, mainly due to its high ionic conductivity, ion transfer rate, and low Ea, demonstrating good compatibility between the solid electrolyte and lithium metal. Further, using a Li / Li symmetric battery, the interfacial stability of the electrolyte to the Li anode and its ability to suppress lithium dendrites were evaluated. Figure 12 As shown, the Li / Li symmetric cell assembled with PHS-CSE experienced a short circuit after 44 hours of cycling. The Li / Li symmetric cell assembled with PEO / LiTFSI showed a decrease in polarization voltage after 355 hours of cycling, indicating that lithium dendrites caused the short circuit. In contrast, the Li | PHSL-CSE | Li symmetric cell exhibited a short circuit at 0.1 mA cm⁻¹. -2 It exhibited long-term cycling stability of over 3600 h at a current density, further verifying the excellent performance of the PHSL-CSE solid electrolyte and its compatibility with lithium metal.

[0114] Supplementary Example 9: Performance Testing of Soft-Pack Lithium Metal Full Cells

[0115] The rate performance and long-cycle performance of the flexible pouch lithium metal full cell prepared in step 2 of Application Example 2 were evaluated. Figure 13As shown, the initial discharge specific capacities of the Li|PHSL-CSE|LFP full cell at current densities of 0.2 C, 0.5 C, 1 C, 2 C, and 3 C are 145.4, 140.6, 137.2, 125.5, and 77.4 mAh g⁻¹, respectively. -1 After 50 charge-discharge cycles, the discharge specific capacity of the Li|PHSL-CSE|LFP full cell can also be restored to 148.5 mAh g when the current density recovers to 0.2C. -1 More importantly, at a current density of 0.2C, the initial specific capacity of the lithium metal full cell fabricated using the PHSL-CSE solid electrolyte membrane can reach 145.5 mAh. -1 After 500 cycles, the battery capacity retention rate reached 91.27%, demonstrating good cycle stability and rate performance. To further verify the application potential of PHSL-CSE in pouch cells, the flexible pouch lithium metal battery prepared in step 2 of Application Example 2 was used to further test the pouch cell's ability to power electrical appliances under extreme test conditions. Figure 14 As shown, in its original state, the pouch battery can continuously and stably power the LED light strip. Even after multiple folds and bending, the pouch battery maintains the brightness of the LED light strip, indicating that the battery has not experienced a short circuit. Furthermore, the pouch battery can still continuously power the LED light under extreme conditions of shearing and puncture. This not only verifies the enormous application potential of our fabricated battery in flexible energy storage devices but also demonstrates the excellent safety and stability of the solid-state lithium metal battery prepared using PHSL-CSE.

[0116] Application Example 2

[0117] A method for preparing a flexible solid-state lithium metal battery and its application, comprising the following steps:

[0118] Step 1: Prepare the cathode material.

[0119] The lithium cobalt oxide (LiCoO2) positive electrode active material was vacuum dried at 100 °C to remove moisture. Super P (conductive carbon black) / lithium cobalt oxide (LiCoO2) / PEO / LiTFSI were ground and dispersed in acetonitrile at a weight ratio of 1:6:2:1 to form a uniform slurry. The slurry was coated onto an aluminum foil current collector and vacuum dried at 80 °C for 24 hours. The active material loading of the positive electrode material was approximately 1.5 mg·cm³. -2 .

[0120] Step 2: Assemble flexible solid-state lithium metal batteries using PHSL-CSE solid electrolyte membranes.

[0121] The positive electrode material and lithium metal sheet prepared in step 1 were used as the positive and negative electrodes, respectively. Nickel metal was used as the negative electrode tab, and aluminum metal strips as the positive electrode tab. The PHSL-CSE composite solid electrolyte membrane prepared in step 3 of Application Example 1 was used as the electrolyte for assembly, and aluminum-plastic film was used as the encapsulation material. The dried positive and negative electrodes were cut into 6 cm × 6 cm individual sheets according to design requirements, and the electrolyte membrane was also cut into 6 cm × 6 cm individual sheets. Then, the electrodes were stacked in the order of positive electrode-solid electrolyte-negative electrode, and the positive and negative electrode tabs were fixed to the electrode sheets with conductive copper tape. Vacuum sealing or needle sealing was used to ensure that the positive and negative electrodes and the electrolyte did not come into contact with air.

[0122] Optical images of the solid-state pouch lithium metal battery obtained by the above method in good working condition under flat, bent, folded, cut, and needle-punctured conditions are shown below. Figure 15 As shown, the flexibility, safety, and stability of the material described in this invention are demonstrated.

[0123] This invention utilizes electrospinning technology to prepare homogenized nanofibers, which reduces the preparation cost of solid electrolyte membranes, improves overall production efficiency, and ensures the stable and reliable performance of energy storage devices.

[0124] By incorporating specific materials such as PVDF-HFP polymers with -CF- groups and succinic anhydride, as well as LLZO inorganic rigid particles, the strength, thermal stability, and ionic conductivity of the solid electrolyte membrane are improved, thus demonstrating significant application potential in flexible wearable energy storage devices. Notably, this invention also utilizes electrospinning to fabricate a three-dimensional network structure ion channel layer. Through physical cross-linking points and a dense PEO / lithium salt layer, the mechanical properties of the electrolyte membrane are effectively improved, lithium dendrite formation is suppressed, and the interfacial stability between lithium metal and the solid electrolyte is enhanced.

[0125] The method for preparing flexible solid-state lithium metal batteries based on the electrospun fiber membrane with organic-inorganic coupling Janus structure of the present invention has the advantages of simple preparation process, controllable loading of positive electrode active material, good battery flexibility, and high safety and stability. Therefore, the electrospun fiber membrane with organic-inorganic coupling Janus structure of the present invention can be used in the preparation of flexible electronic devices and portable electronic products.

Claims

1. A method for preparing an electrospun fiber membrane with an organic-inorganic coupled Janus structure, characterized in that... The method includes the following steps: S1. Preparation of electrospinning solution: The electrospinning solution is a mixture of a first precursor solution and a second precursor solution, with the first precursor solution accounting for 90-95 wt% and the second precursor solution accounting for 5-10 wt%. Preparation of the first precursor solution: 50-80 wt% of polyvinyl fluoride-hexafluoropropylene copolymer (PVDF-HFP), 1-18 wt% of succinate (SN), 10-30 wt% of LLZO and 1-5 wt% of lithium salt were dissolved in an appropriate amount of N,N-dimethylformamide (DMF) and stirred at 30-50°C for at least 12 hours to ensure thorough mixing; the total weight of the solid solute in the first precursor solution was 100%. Preparation of the second precursor solution: 5-10 wt% lithium salt, 20-30 wt% high-viscosity polymer, and 50-60 wt% acetonitrile were stirred at room temperature for more than 12 hours to homogenize the solution; the total weight of the second precursor solution was 100%. S2. The electrospinning solution is electrospinned to prepare a nanofiber membrane, which is then vacuum-dried at 35-50°C for at least 12 hours to obtain the electrospinned fiber membrane with the organic-inorganic coupled Janus structure; in the first precursor fluid... The molecular weight of the PVDF-HFP is 6000-14000; In the second precursor fluid The high-viscosity polymer is selected from one or more of polyethylene oxide (PEO), polyvinylpyrrolidone (PVP), waterborne polyurethane (PU), polyacrylamide (CPAM), hydrolyzed polyacrylamide (HPAM), carboxymethyl starch, acetic starch, hydroxymethyl cellulose, carboxymethyl cellulose (CMC), guar gum, gelatin, or sodium alginate.

2. The preparation method according to claim 1, characterized in that: In the first and second precursor body fluids The lithium salt is independently selected from one or more of lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium bis(fluorosulfonyl)imide (LiFSI), lithium di(oxalate-borate) (LiBOB), lithium di(fluorooxalate-borate) (LiDFOB), lithium di(fluorophosphate) (LiPO2F), or lithium bis(trifluoromethanesulfonyl)imide (LiTFSI).

3. The preparation method according to claim 1, characterized in that: The first and second precursor liquids in S1 are mixed in proportion and stirred at 30±10℃ for more than 6 hours. After uniform mixing, an electrospinning liquid is obtained.

4. The preparation method according to claim 1, characterized in that: During electrospinning in S2, the distance between the drum and the needle is set to 10-15 cm, the feed speed is 0.5-1.5 mL / h, the power supply voltage is set to 5-30 kV, the humidity is controlled below 30%, and the temperature is controlled between 15 ℃ and 35 ℃.

5. An electrospun fiber membrane with an organic-inorganic coupled Janus structure obtained by the preparation method of claim 1.

6. The application of an electrospun fiber membrane with an organic-inorganic coupled Janus structure as described in claim 1 as a solid electrolyte for a battery.

7. The application of an electrospun fiber membrane with an organic-inorganic coupled Janus structure as described in claim 1 in the fabrication of flexible solid-state lithium batteries.

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