Composite solid electrolyte thin film and preparation method and application thereof

Abstract

The application discloses a kind of composite solid electrolyte film and its preparation method and application, the film is obtained by using electrospinning, electrostatic transfer printing, hot roller and polymer infiltration process preparation ultra-thin high ionic conductance composite solid electrolyte film.In which, electrospinning and hot roller guarantee the uniformity of solid electrolyte film, while effectively reducing the thickness of film;Electrostatic transfer printing and hot roller operation combined way makes inorganic particles uniformly distributed in electrolyte film, improves the mechanical strength of composite electrolyte film, while in electrolyte film contact forms ion transmission path, so that polymer film has high ionic conductance;Infiltration in film self-repairing elastic ion-conducting polymer fills the pore in film, has effective adhesion to ceramic particles, while improving the mechanical properties and ion-conducting property of electrolyte film.

Description

Technical Field

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

[0002] Lithium-ion batteries, as highly efficient energy storage devices, possess advantages such as high energy density, long cycle life, high operating voltage, and environmental friendliness, and have been widely used in electric vehicles, microelectronics, aerospace, and other fields. High-energy-density lithium-ion batteries are also attracting increasing attention. Currently, commercial lithium-ion batteries mainly use liquid organic electrolytes, which pose safety risks during use, including electrolyte oxidation and decomposition, continuous growth of the SEI film, and hydrogen evolution of the cathode material. Compared to traditional organic electrolytes, solid-state electrolytes (SSEs) eliminate the safety hazards caused by electrolyte leakage and gas expansion, and offer advantages such as high energy density, high mechanical strength, high safety factor, and low self-discharge rate.

[0003] Currently reported solid-state electrolytes (SSEs) mainly include three types: solid polymer electrolytes (SPEs), inorganic solid-state electrolytes (ISEs), and composite polymer-based solid-state electrolytes (CPEs). Most SSEs have a thickness ranging from 80 to 200 μm. The thickness of the SSE has a significant impact on the energy density of the battery cell; thinner SSEs are easier to achieve higher gravimetric and volumetric energy densities. Furthermore, the SSE also acts as a separator in the battery, but thinning the membrane inevitably reduces its mechanical strength and increases the risk of membrane rupture or Li dendrite penetration, which can ultimately lead to internal short circuits, causing battery failures or even safety issues. Therefore, the main challenge related to thin SSE design lies in the trade-off between minimizing thickness and maintaining mechanical strength. Currently, CPEs composed of an SPE matrix and inorganic fillers can improve the ionic conductivity and mechanical strength of organic electrolytes while effectively addressing interfacial contact issues with inorganic electrolytes. However, most CPEs are over 100 μm thick, and significantly reducing the thickness of CPEs without compromising mechanical properties remains a significant challenge. While casting solid electrolytes (SSEs) directly onto electrodes can yield thinner layers during battery manufacturing, the uniformity of stand-alone films is likely easier to control compared to cast SSE layers. This is because they can be formed on a planar surface rather than cast onto the rough surface of the electrode, and they are easier to integrate with conventional battery fabrication processes. Therefore, controlling the uniformity and processing performance of solid electrolytes remains a challenge in current manufacturing processes. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a composite solid electrolyte film, its preparation method and application. The preparation method mainly includes electrospinning, electrostatic transfer printing and hot rolling processes, which solves the problem of difficulty in controlling uniformity in the traditional doctor blade coating preparation method, and effectively reduces its thickness without affecting the mechanical strength of the composite solid electrolyte.

[0005] To achieve the above objectives, the present invention employs the following technical solution:

[0006] A method for preparing a composite solid electrolyte thin film.

[0007] Inorganic particles are extruded into a polymer film by electrostatic transfer and hot rolling. The polymer film has a polymer network structure to obtain a process electrolyte film. A mixed solution of self-healing ion-conducting elastic polymer and lithium salt is infiltrated into the process electrolyte film to obtain a composite solid electrolyte film.

[0008] A further improvement of the present invention is that:

[0009] Preferably, the polymer film is prepared by electrospinning; the mass ratio of the self-healing elastic ion-conducting polymer to the electrospinning polymer is (10-50):(90-50).

[0010] Preferably, the electrospinning material is one or more of polyethylene oxide, polypropylene carbonate, polytrimethylene carbonate, polyacrylonitrile, polyethyleneimine, polyvinylidene fluoride-hexafluoropropylene copolymer, polyvinylidene fluoride, and polymethyl methacrylate.

[0011] Preferably, the inorganic particles are sulfide-based inorganic electrolytes or oxide-based inorganic electrolytes; the mass ratio of inorganic filler to polymer matrix is ​​(20-95):(80-5), and the mass of polymer matrix is ​​the sum of the masses of polymer film and self-healing ion-conducting elastic polymer.

[0012] The lithium salt is lithium perchlorate, lithium bis(trifluoromethanesulfonyl)imide, lithium bis(fluorosulfonyl)imide, lithium tetrafluoroborate, lithium difluorophosphate, lithium hexafluoroarsenate, or lithium hexafluorophosphate.

[0013] Preferably, the electrostatic transfer and hot rolling process involves inorganic particles on the surface of the rollers being electrostatically adsorbed onto the surface of the polymer film, and the polymer film being squeezed and heated by the two rollers, allowing the inorganic particles to enter the polymer film.

[0014] Preferably, the repair elastic ion-conducting polymer is a polymer containing ether oxygen bonds and having reversible dynamic interactions; the amount of lithium salt added is determined by the ether oxygen bonds in the self-healing ion-conducting elastic polymer.

[0015] Preferably, the molar ratio of the ether oxygen bond to the lithium ion in the lithium salt is (10-30):1.

[0016] Preferably, the polymer containing ether oxygen bonds and having reversible dynamic interactions contains disulfide bonds or hydrogen bonds.

[0017] A composite solid electrolyte film prepared by any of the above preparation methods is characterized in that it comprises a polymer network, the polymer network being encapsulated by a self-healing ion-conducting elastic polymer; lithium salt and inorganic particles are distributed in the polymer network and the self-healing ion-conducting elastic polymer.

[0018] One application of the above-mentioned composite solid electrolyte film is in lithium-ion secondary batteries.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] This invention provides a method for preparing ultrathin, high-ionic-conductivity composite solid electrolyte films using electrospinning, electrostatic transfer, and hot rolling. The electrolyte film has a polymer network formed by electrospinning, which is simultaneously compressed by hot rolling to achieve the target thickness and greater density. This results in a polymer film with high porosity, allowing inorganic particles to penetrate the pores in the polymer network and infiltrate the interior of the polymer, resulting in a more uniform distribution and controllable content of inorganic particles within the polymer network. This method fills the gaps between the spinning framework and ceramic particles with self-healing elastic polymers and lithium salts. In traditional composite solid electrolytes, with increasing deposition time, a large amount of moss-like lithium is generated at the interface, gradually creating gaps between the metallic lithium and the electrolyte. This is due to the low Young's modulus and poor elasticity of the electrolyte. The composite structure of this solid electrolyte membrane endows it with high mechanical strength and excellent interfacial contact. The polymer skeleton formed by electrospinning and the uniformly distributed inorganic particles within the membrane effectively provide sufficient mechanical strength to suppress lithium dendrite growth. The self-healing ion-conducting elastic polymer permeated into the membrane also exhibits excellent resilience, achieving effective electrical contact between the electrolyte and the electrode, thereby improving the mechanical strength of the composite electrolyte membrane and reducing the generation of cracks at the interface. Simultaneously, the permeated self-healing elastic polymer also solves the problem of inorganic particles easily detaching after embedding in the spun membrane, effectively adhering to inorganic particles and enabling large-scale production of the electrolyte membrane while ensuring a uniform and stable structure.

[0021] This invention also discloses a preparation method that can effectively reduce the thickness of the electrolyte and ensure the uniformity of the electrolyte film. The preparation process mainly includes electrospinning, electrostatic transfer printing, and hot rolling. Compared with the traditional blade coating method, the above preparation method can reduce the thickness of the solid electrolyte film from 80-200 μm to 2-50 μm. The electrospinning and rolling processes allow the polymer film to be formed independently, effectively ensuring the uniformity of the polymer film during the forming process. In addition, this process makes it easier to scale up the production of composite solid electrolyte films with excellent performance. Attached Figure Description

[0022] Figure 1 This is a diagram illustrating the preparation process of a solid electrolyte membrane.

[0023] Figure 2 A diagram of a twin-roll press device with electrostatic transfer and heating functions;

[0024] Figure 3 For the rate performance test of Example 1;

[0025] Figure 4 For the rate performance test of Example 2;

[0026] Figure 5 Cyclic performance test for Example 4;

[0027] Figure 6 This is a cycle performance test for Example 5. Detailed Implementation

[0028] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:

[0029] One embodiment of the present invention discloses an ultrathin high ionic conductivity composite solid electrolyte film, comprising a polymer matrix, inorganic filler and lithium salt, with a film thickness of 2-50 μm.

[0030] The polymer matrix comprises a polymer network formed by electrospinning and a self-healing elastic ion-conducting polymer permeated within the membrane, wherein the polymer network is encapsulated by the self-healing elastic ion-conducting polymer. The mass ratio of the self-healing elastic ion-conducting polymer to the electrospinned polymer is (10-50):(90-50); inorganic fillers and lithium salts are uniformly distributed within the self-healing elastic ion-conducting polymer.

[0031] The spinning material is one or more of the following: polyethylene oxide (PEO), polypropylene carbonate (PPC), polytrimethylene carbonate, polyacrylonitrile (PAN), polyethyleneimine (PEI), polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP), polyvinylidene fluoride (PVDF), and polymethyl methacrylate (PMMA).

[0032] The self-healing elastic ion-conducting polymer contains ether-oxygen bonds; the molar ratio of the ether-oxygen bonds to lithium ions in the lithium salt is (10-30):1. This polymer contains ion-conducting groups (ether-oxygen bonds) and possesses a self-healing function based on reversible dynamic interactions. These reversible dynamic interactions include disulfide bonds and hydrogen bonds, enabling self-repair under conditions without external force when damaged. Because the polymer's ability to conduct lithium ions mainly relies on EO groups, the appropriate applicable amount of lithium salt must be determined based on the amount of EO groups.

[0033] The inorganic filler is uniformly distributed within the polymer film, formed by electrostatic transfer onto the polymer film surface and then uniformly embedded within the polymer film using hot rolling. The inorganic filler is a sulfide-based inorganic electrolyte or an oxide-based inorganic electrolyte. Specifically, the sulfide-based inorganic electrolyte is Li₂S-P₂S₅ or Li₇P₃S. 11 Li3PS4 or Li6PS5Cl, with Li7La3Zr2O as the oxide-based inorganic electrolyte. 12 Li 6.4 La3Zr 1.4 Ta 0.6 O 12 Li 0.35 La 0.55 TiO3, Li 1.2 Al 0.2 Ti 1.8 (PO4)3 or Li 1.5 Al 0.5 Ge 1.5 (PO4)3. The inorganic filler is bonded to the polymer film via electrostatic transfer and hot rolling, ensuring a uniform distribution of the inorganic filler within the electrolyte film. All inorganic electrolytes used are in micron-sized or smaller particle form. The mass ratio of inorganic filler to polymer matrix is ​​(20-95):(80-5).

[0034] The lithium salt is lithium perchlorate, lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI), lithium tetrafluoroborate, lithium difluorophosphate, lithium hexafluoroarsenate, or lithium hexafluorophosphate. Preferably, the amount of lithium salt added is determined based on the content of the self-healing elastic polymer in the electrolyte membrane; more preferably, the content of lithium salt is determined based on the proportion of ether oxygen bonds (EO) in the self-healing elastic polymer, with a lithium ion to EO molar ratio of 1:(10-30). The EO groups in the polymer chain can form complexes with lithium ions, enabling the migration of lithium ions within the polymer during polymer chain movement.

[0035] One embodiment of the present invention also discloses a method for preparing an ultrathin high-ionic-conductivity composite solid electrolyte film, wherein the film is an ultrathin high-ionic-conductivity composite solid electrolyte film prepared by electrospinning, electrostatic transfer printing, hot rolling and polymer infiltration processes.

[0036] A polymer film with a three-dimensional skeleton composed of polymer fibers is prepared by electrospinning; electrostatic transfer and hot rolling are carried out simultaneously to compact the polymer film and embed inorganic particles into the polymer film; then, a self-healing ion-conducting elastic polymer is infiltrated into the film to form an ultrathin high ion conductivity composite solid electrolyte film.

[0037] This invention employs electrospinning technology to prepare the three-dimensional framework of a solid electrolyte membrane, avoiding the use of a doctor blade coating method and effectively ensuring the uniformity of the electrolyte membrane. Currently, most composite solid electrolyte membranes have a thickness exceeding 100 μm, while the electrostatic transfer and hot rolling operations used in this invention effectively reduce the membrane thickness to 2-50 μm.

[0038] This invention discloses a composite solid electrolyte film, its preparation method, and its applications. The film is an ultrathin, high-ionic-conductivity composite solid electrolyte film prepared using electrospinning, electrostatic transfer printing, hot rolling, and polymer infiltration processes. Electrospinning and hot rolling ensure the uniformity of the solid electrolyte film and effectively reduce its thickness. The combination of electrostatic transfer printing and hot rolling ensures uniform distribution of inorganic particles within the electrolyte film, improving the mechanical strength of the composite electrolyte film, reducing interface crack formation, and effectively inhibiting lithium dendrite growth. Simultaneously, it forms ion transport pathways within the electrolyte film, giving the polymer film high ionic conductivity. The self-healing, elastic, ion-conducting polymer infiltrating the film fills the pores, effectively adhering to ceramic particles, improving the mechanical properties and ion conductivity of the electrolyte film, and enabling self-repair after physical damage, ensuring the overall stability of the electrolyte structure. The ultrathin, high-ionic-conductivity composite solid electrolyte film designed in this invention exhibits high ionic conductivity and excellent cycle stability.

[0039] The polymer used for permeation in this invention is an ion-conducting elastic polymer with self-healing functional groups, which can achieve effective adhesion of inorganic particles and improve the interfacial contact between the electrolyte and the electrode, adapt to the volume change of the electrode during charge and discharge cycles, and achieve self-repair after physical damage, thus ensuring the stability of the overall electrolyte structure.

[0040] Specifically, a method for preparing a composite solid electrolyte thin film includes the following steps:

[0041] Step 1: Dissolve the spinning polymer in N,N-dimethylformamide (DMF) solution, mix and stir to obtain spinning solution, and use electrospinning to prepare polymer film as substrate;

[0042] Step 2: Electrostatic transfer and hot rolling are performed simultaneously to achieve uniform distribution of inorganic particles inside the polymer film.

[0043] Step 3: The mixed solution of self-healing ion-conducting elastic polymer and lithium salt is permeated into the electrolyte film described above, filling the electrolyte skeleton formed by electrospinning, to obtain an ultrathin high ion conductivity composite solid electrolyte film.

[0044] The electrostatic transfer and hot rolling process is completed in one step using a twin-roll press with electrostatic transfer and heating functions. This device contains a powder box and twin rollers; the powder box contains inorganic material particles for transfer. When the polymer film passes through the twin rollers, the inorganic particles on the roller surface are transferred and cover the film surface due to electrostatic adsorption. Simultaneously, the twin rollers compress and heat the film, causing the inorganic particles to embed into the film and form a good bond with the polymer, thus reducing the pores and thickness of the polymer film.

[0045] One embodiment of the present invention discloses a lithium-ion secondary battery, wherein the solid electrolyte in the lithium-ion secondary battery is the aforementioned thin film, the negative electrode is lithium metal, and the positive electrode includes lithium iron phosphate (LFP), ternary positive electrode, lithium cobalt oxide positive electrode, lithium manganese oxide positive electrode, or lithium nickel oxide positive electrode.

[0046] Furthermore, the ternary cathode includes lithium nickel cobalt manganese oxide cathode and lithium nickel cobalt aluminum oxide cathode.

[0047] The present invention will be further described in detail below through specific embodiments.

[0048] Comparative Example 1

[0049] 1. Example of a lithium-ion battery

[0050] In this comparative example, the composite solid electrolyte was prepared by mixing a polymer, inorganic filler, and lithium salt in a solution, pouring the mixture into a mold, and then drying it in an oven to remove the solvent, thus obtaining the composite solid electrolyte membrane. The inorganic filler was distributed in a disordered state within the polymer matrix. The polymer matrix was polyethylene oxide (PEO), the ceramic electrolyte was Li6PS5Cl, and the lithium salt was lithium bis(fluorosulfonyl)imide (LiTFSI). The ether oxygen bond (EO) was bonded to the lithium salt. + The molar ratio is 10:1, and the mass ratio of PEO to Li6PS5Cl is 20:80.

[0051] Example 1

[0052] (1) Electrospinning: 13.5g of DMF was placed in a round-bottom flask, a magnetic stir bar was added, and the flask was placed in a water bath at 60℃. 1.5g of PAN was then slowly added to the stirred flask. The flask was then capped and stirred continuously for 4 hours until the solution was clear and transparent, yielding a 10% PAN spinning solution. The PAN spinning solution was drawn into a 20mL syringe, which was then fixed to the spinning machine's injection pump. A stainless steel needle was attached and connected to a high-voltage power supply. The receiving roller was connected to the negative terminal of the high-voltage power supply. Aluminum foil was attached to the roller as the receiving substrate. The receiving distance was set to 20cm. The injection pump's liquid supply rate was set to 2mL / h, the roller speed to 300r / min, the slide stroke to 20cm, the spinning voltage to 5-15kV, and the timer to 120min. After completion, a PAN film was obtained.

[0053] (2) Electrostatic transfer and hot rolling: Li 6.4 La3Zr 1.4 Ta 0.6 O 12 (LLZTO) granules are loaded into the powder box. After the device is started, the two rollers roll against each other and heat simultaneously. The PAN spun film cloth is placed between the two rollers and enters the device with the rotating rollers. Due to electrostatic adsorption, the two sides of the PAN spun film cloth are covered with LLZTO granule layers. At the same time, the hot roller pressure between the two rollers makes the LLZTO granules evenly embedded in the PAN film cloth and tightly bonded to it.

[0054] (3) Penetrating self-healing elastic polymer: In this embodiment, the polymer selected for penetration is a self-healing elastic polymer PU with ion-conducting properties. The polymer molecule contains disulfide bonds as self-healing functional groups and ether oxygen bonds (EO) for ion conduction. The structural formula of polymer PU is:

[0055]

[0056] Polymer PU and lithium salt LiTFSI were stirred at room temperature for 6 hours to obtain a polymer solution. This polymer solution was then coated onto the surface of the membrane fabric obtained in the previous step, allowing the PU solution to penetrate into the 3D skeleton formed during the electrospinning process of the PAN membrane fabric. The mass ratio of polymer PU to PAN membrane fabric was approximately 40:60. The ion-conducting groups EO in the polymer reacted with the Li in the lithium salt... + The molar ratio was 10:1. The mass ratio of the total polymer to LLZTO was 20:80. The membrane cloth impregnated with the polymer solution was dried in an oven at 80°C for 12 hours to remove the solvent. After drying, an ultrathin high-ionic-conductivity composite solid electrolyte film was obtained. The composite solid electrolyte film was then cut into the required size using a cutting machine for further testing of ionic conductivity and battery assembly.

[0057] Example 2

[0058] (1) Electrospinning: 13.5g of DMF was placed in a round-bottom flask, a magnetic stir bar was added, and the flask was placed in a water bath at 60℃. 1.5g of PEO was then slowly added to the stirred round-bottom flask. The flask was then tightly capped to prevent moisture from entering the conical flask. The mixture was stirred continuously for 4 hours until the solution became clear and transparent, yielding a 10% PEO spinning solution. The PEO spinning solution was drawn into a 20mL syringe, which was then fixed to the spinning machine's injection pump. A stainless steel needle was attached and connected to a high-voltage power supply. The receiving roller was connected to the negative terminal of the high-voltage power supply. Aluminum foil was attached to the roller as the receiving substrate. The receiving distance was set to 20cm. The injection pump's liquid supply rate was set to 2mL / h, the roller speed to 300r / min, the slide stroke to 20cm, the spinning voltage to 5-15kV, and the timer to 120min. A PEO membrane was obtained after the spinning process.

[0059] (2) Electrostatic transfer and hot roller pressing: LLZTO particles are loaded into the powder box. After the device is started, the two rollers roll against each other and are heated at the same time. The PEO spun film cloth is placed between the two rollers and enters the device with the rotating rollers. Due to electrostatic adsorption, the two sides of the PEO spun film cloth are covered with LLZTO particle layers. At the same time, the hot roller pressing between the two rollers makes the LLZTO particles evenly embedded in the PAN film cloth and tightly bonded to it.

[0060] (3) Penetrating self-healing elastic polymer: In this embodiment, the polymer selected for penetration is a self-healing elastic polymer PU with ion-conducting properties. The polymer molecule contains disulfide bonds as self-healing functional groups and ether oxygen bonds (EO) for ion conduction. The structural formula of polymer PU is:

[0061]

[0062] Polymer PU and lithium salt LiTFSI were stirred at room temperature for 6 hours to obtain a polymer solution. This polymer solution was then coated onto the surface of the membrane fabric obtained in the previous step, allowing the PU solution to penetrate into the 3D skeleton formed during the electrospinning process of the PEO membrane fabric. The mass ratio of polymer PU to PEO membrane fabric was approximately 40:60. The ion-conducting groups EO in the PU polymer react with the Li in the lithium salt... + The molar ratio was 10:1. The mass ratio of the total polymer to LLZTO was 20:80. The membrane cloth impregnated with the polymer solution was dried in an oven at 80°C for 12 hours to remove the solvent. After drying, an ultrathin high-ionic-conductivity composite solid electrolyte film was obtained. The composite solid electrolyte film was then cut into the required size using a cutting machine for further testing of ionic conductivity and battery assembly. Figure 3The rate performance diagram of the full cell using this polymer-based electrolyte shows that the discharge specific capacity reaches 143 mAh / g under charge-discharge cycle conditions at a rate of 2C, exhibiting excellent rate performance similar to Example 1. This indicates that this polymer-based solid electrolyte can be adapted to different electrode materials and demonstrates excellent electrochemical performance.

[0063] Example 3

[0064] (1) Electrospinning: 13.5g of DMF was placed in a round-bottom flask, a magnetic stir bar was added, and the flask was placed in a water bath at 60℃. Then, 1.5g of PVDF was slowly added to the stirred round-bottom flask. The flask was then tightly capped to prevent moisture from entering the conical flask. The mixture was stirred continuously for 4 hours until the solution became clear and transparent, yielding a 10% PVDF spinning solution. The PVDF spinning solution was drawn into a 20mL syringe, which was then fixed to the spinning machine's injection pump. A stainless steel needle was attached and connected to a high-voltage power supply. The receiving roller was connected to the negative terminal of the high-voltage power supply. Aluminum foil was attached to the roller as the receiving substrate. The receiving distance was set to 20cm. The injection pump's liquid supply rate was set to 2mL / h, the roller speed to 300r / min, the slide stroke to 20cm, the spinning voltage to 5-15kV, and the timer to 120min. After completion, a PVDF membrane was obtained.

[0065] (2) Electrostatic transfer and hot roller pressing: LLZTO particles are loaded into the powder box. After the device is started, the two rollers roll against each other and are heated at the same time. The PVDF spun film cloth is placed between the two rollers and enters the device with the rotating rollers. Due to electrostatic adsorption, the two sides of the PVDF spun film cloth are covered with LLZTO particle layers. At the same time, the hot roller pressing between the two rollers makes the LLZTO particles evenly embedded in the PVDF film cloth and tightly bonded to it.

[0066] (3) Penetrating self-healing elastic polymer: In this embodiment, the polymer selected for penetration is a self-healing elastic polymer PU with ion-conducting properties. The polymer molecule contains disulfide bonds as self-healing functional groups and ether oxygen bonds (EO) for ion conduction. The structural formula of polymer PU is:

[0067]

[0068] Polymer PU and lithium salt LiTFSI were stirred at room temperature for 6 hours to obtain a polymer solution. This polymer solution was then coated onto the surface of the membrane fabric obtained in the previous step, allowing the PU solution to penetrate into the 3D skeleton formed during the electrospinning process of the PVDF membrane fabric. The mass ratio of polymer PU to PAN membrane fabric was approximately 40:60. The ion-conducting groups EO in the PU polymer and Li in the lithium salt... +The molar ratio was 10:1. The mass ratio of the total polymer to LLZTO was 20:80. The membrane cloth impregnated with the polymer solution was dried in an oven at 80°C for 12 hours to remove the solvent. After drying, an ultrathin high-ionic-conductivity composite solid electrolyte film was obtained. The composite solid electrolyte film was then cut into the required size using a cutting machine for further testing of ionic conductivity and battery assembly. Figure 4 Cycling data for a full battery assembled using this polymer-based electrolyte showed that after 200 cycles at a rate of 0.5C, the battery retained up to 92% of its capacity, demonstrating that the "sandwich" structure composite solid electrolyte can effectively maintain structural integrity and improve battery cycle stability during battery cycling.

[0069] Example 4

[0070] (1) Electrospinning: 13.5g of DMF was placed in a round-bottom flask, a magnetic stir bar was added, and the flask was placed in a water bath at 60℃. 1.5g of PMMA was then slowly added to the stirred round-bottom flask. The flask was then tightly capped to prevent moisture from entering the conical flask. The mixture was stirred continuously for 4 hours until the solution became clear and transparent, yielding a 10% PMMA spinning solution. The PMMA spinning solution was drawn into a 20mL syringe, which was then fixed to the spinning machine's injection pump. A stainless steel needle was attached and connected to a high-voltage power supply. The receiving roller was connected to the negative terminal of the high-voltage power supply. Aluminum foil was attached to the roller as the receiving substrate. The receiving distance was set to 20cm. The injection pump's liquid supply rate was set to 2mL / h, the roller speed to 300r / min, the slide stroke to 20cm, the spinning voltage to 5-15kV, and the timer to 120min. After completion, a PMMA membrane was obtained.

[0071] (2) Electrostatic transfer and hot roller pressing: LLZTO particles are loaded into the powder box. After the device is started, the two rollers roll against each other and are heated at the same time. The PMMA spun film cloth is placed between the two rollers and enters the device with the rotating rollers. Due to electrostatic adsorption, the two sides of the PMMA spun film cloth are covered with LLZTO particle layers. At the same time, the hot roller pressing between the two rollers makes the LLZTO particles on the surface tightly bonded to the PMMA film cloth. At the same time, the hot roller pressing between the two rollers makes the LLZTO particles evenly embedded in the PMMA film cloth and tightly bonded to it.

[0072] (3) Penetrating self-healing elastic polymer: In this embodiment, the polymer selected for penetration is a self-healing elastic polymer PU with ion-conducting properties. The polymer molecule contains disulfide bonds as self-healing functional groups and ether oxygen bonds (EO) for ion conduction. The structural formula of polymer PU is:

[0073]

[0074] Polymer PU and lithium salt LiTFSI were stirred at room temperature for 6 hours to obtain a polymer solution. This polymer solution was then coated onto the surface of the membrane fabric obtained in the previous step, allowing the PU solution to penetrate into the 3D skeleton formed during the electrospinning process of the PMMA membrane fabric. The mass ratio of polymer PU to PMMA membrane fabric was approximately 40:60. The ion-conducting groups EO in the polymer reacted with the Li in the lithium salt... + The molar ratio was 10:1. The mass ratio of the total polymer to LLZTO was 20:80. The membrane cloth impregnated with the polymer solution was dried in an oven at 80°C for 12 hours to remove the solvent. After drying, an ultrathin high-ionic-conductivity composite solid electrolyte film was obtained. The composite solid electrolyte film was then cut into the required size using a cutting machine for further testing of ionic conductivity and battery assembly.

[0075] Figure 5 For full-cell cycling data using this polymer-based electrolyte, after 400 cycles at a rate of 0.5C, the capacity retention was 92%, demonstrating that the "sandwich structure" solid electrolyte membrane has excellent mechanical properties, can adapt to the volume changes of the electrodes during battery cycling, maintain the stability of the electrolyte structure itself, and its self-healing properties can also effectively maintain the electrode structure, thereby achieving stable long-term battery cycling.

[0076] Example 5

[0077] (1) Electrospinning: 13.5g of DMF was placed in a round-bottom flask, a magnetic stir bar was added, and the flask was placed in a water bath at 60℃. Then, 0.75g of PAN and 0.75g of PEO were slowly added to the stirred round-bottom flask. The flask was then tightly capped to prevent moisture from entering the conical flask. The mixture was stirred continuously for 4 hours until the solution became clear and transparent, yielding a 10% PAN-PEO spinning solution. The PAN-PEO spinning solution was drawn into a 20mL syringe, which was then fixed to the injection pump of the spinning machine. A stainless steel needle was attached and connected to a high-voltage power supply. The receiving roller was connected to the negative terminal of the high-voltage power supply. Aluminum foil was attached to the roller as the receiving substrate. The receiving distance was set to 20cm. The injection pump's liquid supply rate was set to 2mL / h, the roller speed to 300r / min, the slide stroke to 20cm, the spinning voltage to 5-15kV, and the timer to 120min. After completion, a PAN-PEO membrane was obtained.

[0078] (2) Electrostatic transfer and hot roller pressing: LLZTO particles are loaded into the powder box. After the device is started, the two rollers roll against each other and are heated at the same time. The PAN-PEO spun film cloth is placed between the two rollers and enters the device with the rotating rollers. Due to electrostatic adsorption, the two sides of the PAN-PEO spun film cloth are covered with LLZTO particle layers. At the same time, the hot roller pressing between the two rollers makes the LLZTO particles on the surface tightly bonded to the PAN-PEO film cloth. At the same time, the hot roller pressing between the two rollers makes the LLZTO particles evenly embedded in the PAN-PEO film cloth and tightly bonded to it.

[0079] (3) Penetrating self-healing elastic polymer: In this embodiment, the polymer selected for penetration is a self-healing elastic polymer PU with ion-conducting properties. The polymer molecule contains disulfide bonds as self-healing functional groups and ether oxygen bonds (EO) for ion conduction. The structural formula of polymer PU is:

[0080]

[0081] Polymer PU and lithium salt LiTFSI were stirred at room temperature for 6 hours to obtain a polymer solution. This polymer solution was then coated onto the surface of the membrane fabric obtained in the previous step, allowing the PU solution to penetrate into the 3D skeleton formed during the electrospinning process of the PAN-PEO membrane fabric. The mass ratio of polymer PU to PAN-PEO membrane fabric was approximately 40:60. The ion-conducting groups EO in the polymer reacted with the Li in the lithium salt... + The molar ratio was 10:1. The mass ratio of the total polymer to LLZTO was 20:80. The membrane cloth impregnated with the polymer solution was dried in an oven at 80°C for 12 hours to remove the solvent. After drying, an ultrathin high-ionic-conductivity composite solid electrolyte film was obtained. The composite solid electrolyte film was then cut into the required size using a cutting machine for further testing of ionic conductivity and battery assembly.

[0082] Example 6

[0083] (1) Electrospinning: 13.5g of DMF was placed in a round-bottom flask, a magnetic stir bar was added, and the flask was placed in a water bath at 60℃. 1.5g of PAN was then slowly added to the stirred round-bottom flask. The flask was then tightly capped to prevent moisture from entering the conical flask. The mixture was stirred continuously for 4 hours until the solution became clear and transparent, yielding a 10% PAN spinning solution. The PAN spinning solution was drawn into a 20mL syringe, which was then fixed to the injection pump of the spinning machine. A stainless steel needle was attached and connected to a high-voltage power supply. The receiving roller was connected to the negative terminal of the high-voltage power supply. Aluminum foil was attached to the roller as the receiving substrate. The receiving distance was set to 20cm. The injection pump's liquid supply rate was set to 2mL / h, the roller speed to 300r / min, the slide stroke to 20cm, the spinning voltage to 5-15kV, and the timer to 120min. After completion, a PAN film was obtained.

[0084] (2) Electrostatic transfer and hot roller pressing: Li6PS5Cl particles are loaded into the powder box. After the device is started, the two rollers roll against each other and are heated at the same time. The PAN spun film cloth is placed between the two rollers and enters the device with the rotating rollers. Due to electrostatic adsorption, the two sides of the PAN spun film cloth are covered with Li6PS5Cl particle layers. At the same time, the hot roller pressing between the two rollers makes the Li6PS5Cl particles on the surface tightly bonded to the PAN film cloth. At the same time, the hot roller pressing between the two rollers makes the Li6PS5Cl particles evenly embedded in the PAN film cloth and tightly bonded to it.

[0085] (3) Penetrating self-healing elastic polymer: In this embodiment, the polymer selected for penetration is a self-healing elastic polymer PU with ion-conducting properties. The polymer molecule contains disulfide bonds as self-healing functional groups and ether oxygen bonds (EO) for ion conduction. The structural formula of polymer PU is:

[0086]

[0087] Polymer PU and lithium salt LiTFSI were stirred at room temperature for 6 hours to obtain a polymer solution. This polymer solution was then coated onto the surface of the membrane fabric obtained in the previous step, allowing the PU solution to penetrate into the 3D skeleton formed during the electrospinning process of the PAN membrane fabric. The mass ratio of polymer PU to PAN membrane fabric was approximately 40:60. The ion-conducting groups EO in the polymer reacted with the Li in the lithium salt... + The molar ratio of polymer to Li6PS5Cl was 10:1. The mass ratio of the total polymer to Li6PS5Cl was 20:80. The membrane cloth impregnated with the polymer solution was dried in an oven at 80°C for 12 hours to remove the solvent. After drying, an ultrathin high-ionic-conductivity composite solid electrolyte film was obtained. The composite solid electrolyte film was then cut into the required size using a cutting machine for further testing of ionic conductivity and battery assembly.

[0088] Example 7

[0089] (1) Electrospinning: 13.5g of DMF was placed in a round-bottom flask, a magnetic stir bar was added, and the flask was placed in a water bath at 60℃. 1.5g of PEO was then slowly added to the stirred round-bottom flask. The flask was then tightly capped to prevent moisture from entering the conical flask. The mixture was stirred continuously for 4 hours until the solution became clear and transparent, yielding a 10% PEO spinning solution. The PEO spinning solution was drawn into a 20mL syringe, which was then fixed to the spinning machine's injection pump. A stainless steel needle was attached and connected to a high-voltage power supply. The receiving roller was connected to the negative terminal of the high-voltage power supply. Aluminum foil was attached to the roller as the receiving substrate. The receiving distance was set to 20cm. The injection pump's liquid supply rate was set to 2mL / h, the roller speed to 300r / min, the slide stroke to 20cm, the spinning voltage to 5-15kV, and the timer to 120min. A PEO membrane was obtained after the spinning process.

[0090] (2) Electrostatic transfer and hot roller pressing: Li6PS5Cl particles are loaded into the powder box. After the device is started, the two rollers roll against each other and are heated at the same time. The PEO spun film cloth is placed between the two rollers and enters the device with the rotating rollers. Due to electrostatic adsorption, the two sides of the PEO spun film cloth are covered with Li6PS5Cl particle layers. At the same time, the hot roller pressing between the two rollers makes the Li6PS5Cl particles evenly embedded in the PEO film cloth and tightly bonded to it.

[0091] (3) Penetrating self-healing elastic polymer: In this embodiment, the polymer selected for penetration is a self-healing elastic polymer PU with ion-conducting properties. The polymer molecule contains disulfide bonds as self-healing functional groups and ether oxygen bonds (EO) for ion conduction. The structural formula of polymer PU is:

[0092]

[0093] Polymer PU and lithium salt LiTFSI were stirred at room temperature for 6 hours to obtain a polymer solution. This polymer solution was then coated onto the surface of the membrane fabric obtained in the previous step, allowing the PU solution to penetrate into the 3D skeleton formed during the electrospinning process of the PEO membrane fabric. The mass ratio of polymer PU to PEO membrane fabric was approximately 40:60. The ion-conducting groups EO in the polymer react with the Li in the lithium salt. + The molar ratio of polymer to Li6PS5Cl was 10:1. The mass ratio of the total polymer to Li6PS5Cl was 20:80. The membrane cloth impregnated with the polymer solution was dried in an oven at 80°C for 12 hours to remove the solvent. After drying, an ultrathin high-ionic-conductivity composite solid electrolyte film was obtained. The composite solid electrolyte film was then cut into the required size using a cutting machine for further testing of ionic conductivity and battery assembly.

[0094] Figure 6To test the rate performance of the polymer-based electrolyte in a full-cell battery and compare it with the examples, the experimental results showed that its rate performance was far superior to that of the examples. Under 2C rate conditions, the discharge specific capacity could still reach 115 mAh / g. The excellent rate performance is due to the higher ionic conductivity of the electrolyte compared to the examples.

[0095] Example 8

[0096] (1) Electrospinning: 13.5g of DMF was placed in a round-bottom flask, a magnetic stir bar was added, and the flask was placed in a water bath at 60℃. Then, 1.5g of PVDF was slowly added to the stirred round-bottom flask. The flask was then tightly capped to prevent moisture from entering the conical flask. The mixture was stirred continuously for 4 hours until the solution became clear and transparent, yielding a 10% PVDF spinning solution. The PVDF spinning solution was drawn into a 20mL syringe, which was then fixed to the spinning machine's injection pump. A stainless steel needle was attached and connected to a high-voltage power supply. The receiving roller was connected to the negative terminal of the high-voltage power supply. Aluminum foil was attached to the roller as the receiving substrate. The receiving distance was set to 20cm. The injection pump's liquid supply rate was set to 2mL / h, the roller speed to 300r / min, the slide stroke to 20cm, the spinning voltage to 5-15kV, and the timer to 120min. After completion, a PVDF membrane was obtained.

[0097] (2) Electrostatic transfer and hot roller pressing: Li6PS5Cl particles are loaded into the powder box. After the device is started, the two rollers roll against each other and are heated at the same time. The PVDF spun film cloth is placed between the two rollers and enters the device with the rotating rollers. Due to electrostatic adsorption, the two sides of the PVDF spun film cloth are covered with Li6PS5Cl particle layers. At the same time, the hot roller pressing between the two rollers makes the Li6PS5Cl particles evenly embedded in the PVDF film cloth and tightly bonded to it.

[0098] (3) Penetrating self-healing elastic polymer: In this embodiment, the polymer selected for penetration is a self-healing elastic polymer PU with ion-conducting properties. The polymer molecule contains disulfide bonds as self-healing functional groups and ether oxygen bonds (EO) for ion conduction. The structural formula of polymer PU is:

[0099]

[0100] Polymer PU and lithium salt LiTFSI were stirred at room temperature for 6 hours to obtain a polymer solution. This polymer solution was then coated onto the surface of the membrane fabric obtained in the previous step, allowing the PU solution to penetrate into the 3D skeleton formed during the electrospinning process of the PVDF membrane fabric. The mass ratio of polymer PU to PVDF membrane fabric was approximately 40:60. The ion-conducting groups EO in the polymer reacted with the Li in the lithium salt... +The molar ratio of polymer to Li6PS5Cl was 10:1. The mass ratio of the total polymer to Li6PS5Cl was 20:80. The membrane cloth impregnated with the polymer solution was dried in an oven at 80°C for 12 hours to remove the solvent. After drying, an ultrathin high-ionic-conductivity composite solid electrolyte film was obtained. The composite solid electrolyte film was then cut into the required size using a cutting machine for further testing of ionic conductivity and battery assembly.

[0101] Example 9

[0102] (1) Electrospinning: 13.5g of DMF was placed in a round-bottom flask, a magnetic stir bar was added, and the flask was placed in a water bath at 60℃. 1.5g of PMMA was then slowly added to the stirred round-bottom flask. The flask was then tightly capped to prevent moisture from entering the conical flask. The mixture was stirred continuously for 4 hours until the solution became clear and transparent, yielding a 10% PMMA spinning solution. The PMMA spinning solution was drawn into a 20mL syringe, which was then fixed to the spinning machine's injection pump. A stainless steel needle was attached and connected to a high-voltage power supply. The receiving roller was connected to the negative terminal of the high-voltage power supply. Aluminum foil was attached to the roller as the receiving substrate. The receiving distance was set to 20cm. The injection pump's liquid supply rate was set to 2mL / h, the roller speed to 300r / min, the slide stroke to 20cm, the spinning voltage to 5-15kV, and the timer to 120min. After completion, a PMMA membrane was obtained.

[0103] (2) Electrostatic transfer and hot roller pressing: Li6PS5Cl particles are loaded into the powder box. After the device is started, the two rollers roll against each other and are heated at the same time. The PMMA spun film cloth is placed between the two rollers and enters the device with the rotating rollers. Due to electrostatic adsorption, the two sides of the PMMA spun film cloth are covered with Li6PS5Cl particle layers. At the same time, the hot roller pressing between the two rollers makes the Li6PS5Cl particles evenly embedded in the PMMA film cloth and tightly bonded to it.

[0104] (3) Penetrating self-healing elastic polymer: In this embodiment, the polymer selected for penetration is a self-healing elastic polymer PU with ion-conducting properties. The polymer molecule contains disulfide bonds as self-healing functional groups and ether oxygen bonds (EO) for ion conduction. The structural formula of polymer PU is:

[0105]

[0106] Polymer PU and lithium salt LiTFSI were stirred at room temperature for 6 hours to obtain a polymer solution. This polymer solution was then coated onto the surface of the membrane fabric obtained in the previous step, allowing the PU solution to penetrate into the 3D skeleton formed during the electrospinning process of the PMMA membrane fabric. The mass ratio of polymer PU to PMMA membrane fabric was approximately 40:60. The ion-conducting groups EO in the polymer reacted with the Li in the lithium salt... +The molar ratio of polymer to Li6PS5Cl was 10:1. The mass ratio of the total polymer to Li6PS5Cl was 20:80. The membrane cloth impregnated with the polymer solution was dried in an oven at 80°C for 12 hours to remove the solvent. After drying, an ultrathin high-ionic-conductivity composite solid electrolyte film was obtained. The composite solid electrolyte film was then cut into the required size using a cutting machine for further testing of ionic conductivity and battery assembly.

[0107] Example 10

[0108] (1) Electrospinning: 13.5g of DMF was placed in a round-bottom flask, a magnetic stir bar was added, and the flask was placed in a water bath at 60℃. 1.5g of PAN was then slowly added to the stirred round-bottom flask. The flask was then tightly capped to prevent moisture from entering the conical flask. The mixture was stirred continuously for 4 hours until the solution became clear and transparent, yielding a 10% PAN spinning solution. The PAN spinning solution was drawn into a 20mL syringe, which was then fixed to the injection pump of the spinning machine. A stainless steel needle was attached and connected to a high-voltage power supply. The receiving roller was connected to the negative terminal of the high-voltage power supply. Aluminum foil was attached to the roller as the receiving substrate. The receiving distance was set to 20cm. The injection pump's liquid supply rate was set to 2mL / h, the roller speed to 300r / min, the slide stroke to 20cm, the spinning voltage to 5-15kV, and the timer to 120min. After completion, a PAN film was obtained.

[0109] (2) Electrostatic transfer and hot roller pressing: LLZTO particles are loaded into the powder box. After the device is started, the two rollers roll against each other and are heated at the same time. The PAN spun film cloth is placed between the two rollers and enters the device with the rotating rollers. Due to electrostatic adsorption, the two sides of the PAN spun film cloth are covered with LLZTO particle layers. At the same time, the hot roller pressing between the two rollers makes the LLZTO particles evenly embedded in the PAN film cloth and tightly bonded to it.

[0110] (3) Penetrating self-healing elastic polymer: In this embodiment, the polymer selected for penetration is PU2, a self-healing elastic polymer with ion-conducting properties. The polymer molecule contains disulfide bonds as self-healing functional groups and ether oxygen bonds (EO) for ion conduction. The structural formula of polymer PU2 is:

[0111]

[0112] Polymer PU2 and lithium salt LiFSI were stirred at room temperature for 6 hours to obtain a polymer solution. This polymer solution was then coated onto the surface of the membrane fabric obtained in the previous step, allowing the PU2 solution to penetrate into the 3D skeleton formed during the electrospinning process of the PAN membrane fabric. The mass ratio of polymer PU2 to PAN membrane fabric was approximately 40:60. The ion-conducting groups EO in the polymer reacted with the Li in the lithium salt... +The molar ratio was 10:1. The mass ratio of the total polymer to LLZTO was 20:80. The membrane cloth impregnated with the polymer solution was dried in an oven at 80°C for 12 hours to remove the solvent. After drying, an ultrathin high-ionic-conductivity composite solid electrolyte film was obtained. The composite solid electrolyte film was then cut into the required size using a cutting machine for further testing of ionic conductivity and battery assembly.

[0113] Example 11

[0114] (1) Electrospinning: 13.5g of DMF was placed in a round-bottom flask, a magnetic stir bar was added, and the flask was placed in a water bath at 60℃. Then, 0.75g of PAN and 0.75g of PEI were slowly added to the stirred round-bottom flask. The flask was then tightly capped to prevent moisture from entering the conical flask. The mixture was stirred continuously for 4 hours until the solution became clear and transparent, yielding a 10% PAN-PEI spinning solution. The PAN-PEI spinning solution was drawn into a 20mL syringe, which was then fixed to the injection pump of the spinning machine. A stainless steel needle was attached and connected to a high-voltage power supply. The receiving roller was connected to the negative terminal of the high-voltage power supply. Aluminum foil was attached to the roller as the receiving substrate. The receiving distance was set to 20cm. The injection pump's liquid supply rate was set to 2mL / h, the roller speed to 300r / min, the slide stroke to 20cm, the spinning voltage to 5-15kV, and the timer to 120min. After completion, a PAN-PEI membrane was obtained.

[0115] (2) Electrostatic transfer and hot roller pressing: LLZTO particles are loaded into the powder box. After the device is started, the two rollers roll against each other and are heated at the same time. The PAN-PEI spun film cloth is placed between the two rollers and enters the device with the rotating rollers. Due to electrostatic adsorption, the two sides of the PAN-PEI spun film cloth are covered with LLZTO particle layers. At the same time, the hot roller pressing between the two rollers makes the LLZTO particles evenly embedded in the PAN-PEI film cloth and tightly bonded to it.

[0116] (3) Penetrating self-healing elastic polymer: In this embodiment, the polymer selected for penetration is PU2, a self-healing elastic polymer with ion-conducting properties. The polymer molecule contains disulfide bonds as self-healing functional groups and ether oxygen bonds (EO) for ion conduction. The structural formula of polymer PU2 is:

[0117]

[0118] Polymer PU and lithium salt LiFSI were stirred at room temperature for 6 hours to obtain a polymer solution. This polymer solution was then coated onto the surface of the membrane fabric obtained in the previous step, allowing the PU2 solution to penetrate into the 3D skeleton formed during the electrospinning process of the PAN-PEI membrane fabric. The mass ratio of polymer PU2 to PAN-PEI membrane fabric was approximately 40:60. The ion-conducting groups EO in the polymer reacted with the Li in the lithium salt...+ The molar ratio was 10:1. The mass ratio of the total polymer to LLZTO was 20:80. The membrane cloth impregnated with the polymer solution was dried in an oven at 80°C for 12 hours to remove the solvent. After drying, an ultrathin high-ionic-conductivity composite solid electrolyte film was obtained. The composite solid electrolyte film was then cut into the required size using a cutting machine for further testing of ionic conductivity and battery assembly.

[0119] Example 12

[0120] (1) Electrospinning: 13.5g of DMF was placed in a round-bottom flask, a magnetic stir bar was added, and the flask was placed in a water bath at 60℃. Then, 0.75g of PEO and 0.75g of PPC were slowly added to the stirred round-bottom flask. The flask was then tightly capped to prevent moisture from entering the conical flask. The mixture was stirred continuously for 4 hours until the solution became clear and transparent, yielding a 10% PEO-PPC spinning solution. The PEO-PPC spinning solution was drawn into a 20mL syringe, which was then fixed to the spinning machine's injection pump. A stainless steel needle was attached and connected to a high-voltage power supply. The receiving roller was connected to the negative terminal of the high-voltage power supply. Aluminum foil was attached to the roller as the receiving substrate. The receiving distance was set to 20cm. The injection pump's liquid supply rate was set to 2mL / h, the roller speed to 300r / min, the slide stroke to 20cm, the spinning voltage to 5-15kV, and the timer to 120min. After completion, a PEO-PPC membrane was obtained.

[0121] (2) Electrostatic transfer and hot roller pressing: LLZTO particles are loaded into the powder box. After the device is started, the two rollers roll against each other and are heated at the same time. The PEO-PPC spun film cloth is placed between the two rollers and enters the device with the rotating rollers. Due to electrostatic adsorption, the two sides of the PEO-PPC spun film cloth are covered with LLZTO particle layers. At the same time, the hot roller pressing between the two rollers makes the LLZTO particles evenly embedded in the PEO-PPC film cloth and tightly bonded to it.

[0122] (3) Penetrating self-healing elastic polymer: In this embodiment, the polymer selected for penetration is PU2, a self-healing elastic polymer with ion-conducting properties. The polymer molecule contains disulfide bonds as self-healing functional groups and ether oxygen bonds (EO) for ion conduction. The structural formula of polymer PU2 is:

[0123]

[0124] Polymer PU and lithium salt LiFSI were stirred at room temperature for 6 hours to obtain a polymer solution. This polymer solution was then coated onto the surface of the membrane fabric obtained in the previous step, allowing the PU2 solution to penetrate into the 3D skeleton formed during the electrospinning process of the PEO-PPC membrane fabric. The mass ratio of polymer PU2 to PEO-PPC membrane fabric was approximately 40:60. The ion-conducting groups EO in the polymer reacted with the Li in the lithium salt... + The molar ratio was 10:1. The mass ratio of the total polymer to LLZTO was 20:80. The membrane cloth impregnated with the polymer solution was dried in an oven at 80°C for 12 hours to remove the solvent. After drying, an ultrathin high-ionic-conductivity composite solid electrolyte film was obtained. The composite solid electrolyte film was then cut into the required size using a cutting machine for further testing of ionic conductivity and battery assembly.

[0125] As shown in Table 1, the ultrathin high-ionic-conductivity composite solid electrolyte film designed in this invention exhibits higher ionic conductivity and superior cycle stability compared to the comparative example. Firstly, the solid electrolyte film of this structure improves the ionic conductivity of the electrolyte through the combination of high-ionic-conductivity polymers and inorganic materials. As shown in Table 1, the ionic conductivity of the electrolyte film is more than twice that of the comparative example. Secondly, the electrolyte film possesses excellent mechanical properties through the design of a three-dimensional framework structure and the electrostatic transfer and hot-pressing of inorganic particles. The self-healing elastic polymer penetrating into the framework can effectively adhere to the inorganic particles and adapt to changes in electrode volume, effectively ensuring the structural integrity of the electrolyte film, thereby achieving the excellent cycle stability shown in Table 1.

[0126] Table 1 Performance comparison of comparative examples and embodiments

[0127]

[0128]

[0129] Example 13

[0130] In this embodiment, the self-healing elastic polymer is a polymer containing hydrogen bonds, with the following structural formula:

[0131]

[0132] The remaining parts not covered are the same as in Example 1.

[0133] Example 14

[0134] In this embodiment, the lithium salt used is lithium perchlorate, and the other parts not involved are the same as in Example 1.

[0135] Example 15

[0136] In this embodiment, the lithium salt used is lithium tetrafluoroborate, and the other parts not involved are the same as in Example 1.

[0137] Example 16

[0138] In this embodiment, the lithium salt used is lithium difluorophosphate, and the other parts not involved are the same as in Example 1.

[0139] Example 17

[0140] In this embodiment, the lithium salt used is lithium hexafluoroarsenate, and the other parts not involved are the same as in Example 1.

[0141] Example 18

[0142] In this embodiment, the lithium salt used is lithium hexafluorophosphate, and the other parts not involved are the same as in Example 1.

[0143] Example 19

[0144] In this embodiment, the mass ratio of polymer PU to PAN film is approximately 10:90, and the remaining parts are the same as in Example 1.

[0145] Example 20

[0146] In this embodiment, the mass ratio of polymer PU to PAN film is approximately 20:80, and the remaining parts are the same as in Example 1.

[0147] Example 21

[0148] In this embodiment, the mass ratio of polymer PU to PAN film is approximately 50:50, and the remaining parts are the same as in Example 1.

[0149] Example 22

[0150] In this embodiment, the mass ratio of polymer PU to PAN film is approximately 30:70, and the remaining parts are the same as in Example 1.

[0151] Example 23

[0152] In this embodiment, the mass ratio of inorganic filler to polymer matrix is ​​approximately 20:80, and the remaining parts are the same as in Example 1.

[0153] Example 24

[0154] In this embodiment, the mass ratio of inorganic filler to polymer matrix is ​​approximately 40:60, and the remaining parts are the same as in Example 1.

[0155] Example 25

[0156] In this embodiment, the mass ratio of inorganic filler to polymer matrix is ​​approximately 70:30, and the remaining parts are the same as in Example 1.

[0157] Example 26

[0158] In this embodiment, the mass ratio of inorganic filler to polymer matrix is ​​approximately 95:5, and the remaining parts are the same as in Example 1.

[0159] Example 27

[0160] In this embodiment, the molar ratio of PU ether oxygen bond to lithium ion in lithium salt is 15:1, and the other parts not involved are the same as in Example 1.

[0161] Example 28

[0162] In this embodiment, the molar ratio of PU ether oxygen bond to lithium ion in lithium salt is 20:1, and the other parts not involved are the same as in Example 1.

[0163] Example 29

[0164] In this embodiment, the molar ratio of PU ether oxygen bond to lithium ion in lithium salt is 25:1, and the other parts not involved are the same as in Example 1.

[0165] Example 30

[0166] In this embodiment, the molar ratio of PU ether oxygen bond to lithium ion in lithium salt is 30:1, and the other parts not involved are the same as in Example 1.

[0167] Example 31

[0168] In this embodiment, the spinning solution is polyvinylidene fluoride-hexafluoropropylene copolymer, and the other parts not involved are the same as in Example 1.

[0169] Example 32

[0170] In this embodiment, the spinning solution is polytrimethylene carbonate, and the other parts not involved are the same as in Example 1.

[0171] 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 within the protection scope of the present invention.

Claims

1. A method for preparing a composite solid electrolyte film, characterized in that, inorganic particles are extruded into a polymer film by electrostatic transfer printing and hot rolling, the polymer film is a polymer network structure, a process electrolyte film is obtained, a mixed solution of a self-healing ion-conducting elastomer and a lithium salt is infiltrated into the process electrolyte film, and a composite solid electrolyte film is prepared. The polymer film is prepared by electrospinning; the mass ratio of the self-healing ion-conducting elastomer to the electrospun polymer is (10-50):(90-50).

2. The method of claim 1, wherein the method further comprises: The spinning material for electrospinning is one or more of polyethylene oxide, polypropylene carbonate, polytrimethylene carbonate, polyacrylonitrile, polyethyleneimine, polyvinylidene fluoride-hexafluoropropylene copolymer, polyvinylidene fluoride, and polymethyl methacrylate.

3. The method of claim 2, wherein the method further comprises: The inorganic particles are sulfide-based inorganic electrolytes or oxide-based inorganic electrolytes; the mass ratio of the inorganic filler to the polymer matrix is (20-95):(80-5), and the mass of the polymer matrix is the mass of the polymer film and the self-healing ion-conducting elastomer; 4. The method of claim 1, wherein the method further comprises: The lithium salt is lithium perchlorate, lithium bis(trifluoromethanesulfonyl)imide, lithium bis(fluorosulfonyl)imide, lithium tetrafluoroborate, lithium difluorophosphate, lithium hexafluoroarsenate, or lithium hexafluorophosphate. The process of electrostatic transfer printing and hot rolling is that the inorganic particles on the surface of the roller are covered on the surface of the polymer film by electrostatic adsorption, the polymer film is extruded and heated by a double roller, and the inorganic particles enter the polymer film.

5. The method of claim 1, wherein the method further comprises: The self-healing ion-conducting elastomer is a polymer containing ether oxygen bonds and having reversible dynamic interactions; and the amount of the lithium salt is determined by the ether oxygen bonds in the self-healing ion-conducting elastomer.

6. The method of claim 1, wherein the method further comprises: The molar ratio of the ether oxygen bonds to lithium ions in the lithium salt is (10-30):

1.

7. The method of claim 6, wherein the method further comprises, The polymer containing ether oxygen bonds and having reversible dynamic interactions has disulfide bonds or hydrogen bonds.

8. The method of claim 6, wherein the method further comprises, The polymer network is wrapped by the self-healing ion-conducting elastomer; and the lithium salt and the inorganic particles are distributed in the polymer network and the self-healing ion-conducting elastomer.

9. A composite solid-state electrolyte film prepared by the method of any one of claims 1-8, characterized in that, The composite solid electrolyte film is applied in lithium ion secondary batteries.

10. Use of the composite solid-state electrolyte film according to claim 9, characterized in that ​

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