Pebax / PEO composite solid-state battery and preparation method thereof

Abstract

This invention belongs to the field of solid-state battery technology, specifically relating to a Pebax / PEO composite solid-state battery and its preparation method. The Pebax / PEO composite solid-state battery includes an integrated positive electrode, a negative electrode side film, and a lithium metal sheet. The integrated positive electrode includes a positive electrode and a composite film layer above the positive electrode. The integrated positive electrode is obtained by dissolving a polyether block amide copolymer and a lithium salt, adding inorganic fillers, stirring until homogeneous, casting the resulting composite slurry onto the positive electrode, and then drying. The negative electrode side film is obtained by dissolving polyethylene oxide and a lithium salt, adding inorganic fillers, stirring until homogeneous, casting, and drying. The bilayer composite film, as a solid electrolyte, can better adapt to the high oxidizing properties of the positive electrode material and the high reducing properties of the negative electrode lithium metal, broadening the electrochemical window, improving ionic conductivity and the energy density of the solid-state battery, and ensuring a longer cycle life.

Description

Technical Field

[0001] This invention belongs to the field of solid-state battery technology, specifically relating to a Pebax / PEO composite solid-state battery and its preparation method. Background Technology

[0002] Solid-state batteries are batteries that use solid electrodes and solid electrolytes, eliminating the need for traditional liquid electrolytes. This results in smaller size and easier storage. When used in large equipment such as automobiles, there is no need to add additional cooling pipes, electronic controls, etc., which not only saves costs but also effectively reduces weight. Solid electrolytes have the characteristics of high energy density, small size, and greater safety. They can conduct larger currents, thereby increasing battery capacity, making them ideal batteries for electric vehicles.

[0003] From a materials system perspective, solid-state electrolytes are mainly divided into two categories: inorganic solid-state electrolytes and polymer solid-state electrolytes. Among them, polymer-based solid-state electrolytes exhibit significant advantages due to their unique material properties: on the one hand, the stable interfacial contact characteristics formed between polymer-based solid-state electrolytes and electrode materials can effectively reduce interfacial impedance; on the other hand, polymer-based solid-state electrolytes possess excellent processability and three-dimensional structural adaptability, maintaining high ionic conductivity while their inherent flexibility and high mechanical strength can effectively suppress dendrite growth. Therefore, polymer solid-state electrolytes have become an important material foundation for constructing high-safety, long-cycle-life solid-state battery systems, especially suitable for industrial applications of high-energy-density solid-state batteries.

[0004] Driven by the increasing market demand for lithium-ion battery energy density, in battery systems using ternary lithium materials as the positive electrode and lithium metal as the negative electrode, nickel-cobalt-manganese ternary materials and lithium metal (NCM / Li) solid-state batteries, due to the dual effects of extreme oxidation / reduction environments at the electrode interface, place more stringent performance demands on the electrochemical stability of polymer solid-state electrolytes—requiring simultaneous achievement of high oxidation resistance and reduction resistance. Therefore, this battery system needs to be matched with electrolyte materials that can simultaneously withstand higher oxidation and reduction performance. Existing polymer matrices such as polyethylene oxide (PEO) and polymethyl methacrylate (PMMA), while possessing stable reduction resistance, are prone to oxidative degradation reactions at high voltages above 4.2V, leading to interface failure. Meanwhile, materials such as polyvinylidene fluoride (PVDF) and polyacrylonitrile (PAN), which have advantages in high-voltage tolerance, inherently suffer from reduction side reactions when in contact with the lithium metal negative electrode. The mutually exclusive contradiction between oxidation and reduction stability in these material systems significantly limits their application efficiency in high-performance solid-state battery systems. Therefore, developing novel polymer solid electrolytes that combine a wide electrochemical stability window (>4.5V vs. Li+ / Li) with interfacial chemical inertness has become a key technological obstacle to overcome the compatibility bottleneck of high-voltage cathodes / lithium metal anodes.

[0005] Chinese patent application number 202510014661.8 describes a three-layer stacked solid electrolyte membrane. The positive electrode side uses an oxidation-resistant solid electrolyte to withstand higher voltages. The middle layer employs a porous substrate for support, strengthening the membrane structure. The negative electrode side uses a reduction-resistant electrolyte to stabilize the interface effect with the lithium metal negative electrode. While this three-layer structure broadens the electrochemical window and improves the battery's energy density, the porous substrate in the middle layer cannot completely prevent lithium dendrite penetration, failing to guarantee the effective passage of lithium ions through the complex pores.

[0006] Chinese patent application number 202510063972.3 combines the characteristics of halide solid electrolytes and polymer solid electrolytes to construct a solid electrolyte membrane that combines rigidity and flexibility. This membrane possesses high mechanical properties and also improves the interface issues between the polymer and halide at the positive and negative electrodes, respectively, thus enhancing battery stability. However, the presence of the polymer cannot completely isolate the influence of the lithium metal negative electrode on the halide. During cycling, the polymer-halide interface undergoes some side reactions, reducing battery efficiency. Summary of the Invention

[0007] The purpose of this invention is to address the aforementioned technical problems by providing a Pebax / PEO composite solid-state battery and its preparation method. The battery uses a double-layer film composite as a solid electrolyte, which is integrated to form a positive electrode sheet. Combined with a lithium metal negative electrode, the solid electrolyte can effectively accommodate the high oxidizability of the positive electrode material and the high reducing properties of the lithium metal negative electrode, thereby improving the ionic conductivity of the solid electrolyte and the cycle life of the solid-state battery.

[0008] The Pebax / PEO composite solid-state battery of the present invention includes an integrated positive electrode, a negative electrode side film, and a lithium metal sheet; the integrated positive electrode includes a positive electrode and a composite film layer above the positive electrode; the integrated positive electrode is obtained by dissolving polyether block amide copolymer and lithium salt, adding inorganic filler and stirring evenly, casting the resulting composite slurry onto the positive electrode, and drying. The negative electrode side membrane is obtained by dissolving polyethylene oxide and lithium salt, adding inorganic filler, stirring evenly, casting, and drying.

[0009] The integrated positive electrode sheet of this invention contains an oxidation-resistant composite film layer that can be matched with the positive electrode material. The negative electrode side film has reduction resistance and can be matched with lithium metal negative electrode materials. By using a double-layer film composite as a solid electrolyte, it can effectively accommodate the high oxidation of the positive electrode material and the high reduction of the lithium metal negative electrode, prevent lithium dendrite penetration, improve ionic conductivity, broaden the electrochemical window, ensure stable operation of the battery during operation, extend battery life, and improve energy density.

[0010] Furthermore, in the integrated positive electrode sheet, the thickness of the positive electrode sheet is 20~30μm, the thickness of the composite film layer is 30~100μm, and / or the thickness of the negative electrode side film is 100~200μm.

[0011] Preferably, the integrated positive electrode sheet is obtained by uniformly mixing the positive electrode material, conductive agent and binder with an organic solvent, casting the resulting slurry onto an aluminum foil, and then drying, pressing and stamping; the positive electrode material includes, but is not limited to, any one of lithium iron phosphate, lithium nickel cobalt manganese oxide and lithium nickel cobalt aluminum oxide.

[0012] Furthermore, the hard segment of the polyether block amide copolymer is one or both of nylon 6 and nylon 12, and the soft segment is one or more of polytetrahydrofuran, polybutanediol, and polypropylene glycol.

[0013] Further, the lithium salt is one or more of lithium bis(trifluoromethanesulfonyl)imide (LiTFSi), lithium bis(difluorosulfonyl)imide (LiFSi), lithium hexafluorophosphate (LiPF6), and lithium difluorooxalate borate (LiDFOB); preferably, the lithium salt is one or two of lithium bis(difluorosulfonyl)imide (LiFSi) and lithium difluorooxalate borate (LiDFOB).

[0014] Furthermore, the inorganic filler is one or more of lithium aluminum phosphate titanate, alumina, zeolite imidazole ester framework, and boron nitride. Furthermore, the mass ratio of hard segments to soft segments in the polyether block amide copolymer is 1.5~4.0:1.

[0015] Furthermore, the polyether block amide copolymer has a Shore D hardness of 20 to 70; and / or the polyethylene oxide has a molecular weight of 600,000 to 1,000,000.

[0016] Preferably, the polyether block amide copolymer is selected from one or more of Pebax1657, Pebax30R51, Pebax2533, and Pebax3533; more preferably, it is one or two of Pebax1657 and Pebax2533.

[0017] Furthermore, the mass ratio of polyether block amide copolymer to lithium salt in the integrated positive electrode is 2.5~8.0:1.0.

[0018] Furthermore, the mass ratio of polyethylene oxide to lithium salt in the negative electrode side film is 1.5~3.0:1.0.

[0019] Furthermore, the mass of the inorganic filler in the integrated positive electrode is 10-30% of the mass of the polyether block amide copolymer; and / or the mass of the inorganic filler in the negative electrode side membrane is 10-30% of the mass of the polyethylene oxide.

[0020] By adjusting the composition and ratio of the composite film layer and the negative electrode side film in the integrated positive electrode sheet, the polymer solid electrolyte film has better ion mobility and mechanical strength, reducing film damage and performance degradation during battery charging and discharging.

[0021] Preferably, the integrated positive electrode preparation involves adding polyether block amide copolymer and lithium salt to a sealed container, dissolving them with a solvent, adding inorganic filler and mixing evenly, casting the resulting slurry onto the positive electrode, and drying it to form a film. The negative electrode side film preparation involves adding polyethylene oxide and lithium salt to a sealed container, dissolving them with a solvent, adding inorganic filler and mixing evenly, casting the resulting slurry into a polytetrafluoroethylene mold, and drying it to form a film.

[0022] Furthermore, the dissolution temperature of the polyether block amide copolymer and lithium salt, as well as the polyoxyethylene and lithium salt, is 50~100℃, the stirring speed during dissolution is 300~800rpm, and the stirring time is 4~8h; the preferred dissolution temperature is 60~80℃.

[0023] Preferably, ultrasonic mixing is performed for 10-30 minutes after stirring.

[0024] Furthermore, the solvent in which the polyether block amide copolymer and lithium salt, as well as the polyethylene oxide and lithium salt are dissolved, is one or more of ethanol, acetonitrile, n-butanol, isobutanol, and water.

[0025] Preferably, a solution with a mass concentration of 3.0 to 8.0% is obtained by dissolving the polyether block amide copolymer and lithium salt, as well as the polyethylene oxide and lithium salt.

[0026] Furthermore, during the preparation of the integrated positive electrode sheet, the drying process involves first pre-drying at 30-50℃ for 5-10 hours, and then drying at 60-80℃ for 20-30 hours; and / or during the preparation of the negative electrode side film, the drying process involves drying at 50-80℃ for 20-30 hours.

[0027] Preferably, drying is performed in a vacuum. This invention also provides a method for preparing the above-mentioned Pebax / PEO composite solid-state battery, which involves covering an integrated positive electrode sheet with a negative electrode side film, then stacking lithium metal sheets, and finally pressing them together.

[0028] Furthermore, the compression is performed at 30-50 psi for 10-30 seconds.

[0029] Compared with the prior art, the technical solution of the present invention has the following beneficial effects: (1) The present invention uses a double-layer membrane composite as a solid electrolyte, which can better adapt to the high oxidizing properties of the positive electrode material and the high reducing properties of the negative electrode lithium metal, thus broadening the electrochemical window, improving the ionic conductivity and energy density of the solid battery, and ensuring a long cycle life. (2) The composite film layer on the integrated positive electrode sheet has oxidation resistance and can be matched with the positive electrode material. At the same time, the negative electrode side film has reduction resistance and can be matched with the lithium metal negative electrode material. The combination of the two can improve the side reaction at the interface and ensure that the battery can operate stably during operation. (3) The present invention uses the casting method to obtain an integrated positive electrode sheet, which tightly combines the solid electrolyte membrane with the positive electrode material, simplifies the preparation process, and at the same time ensures the thickness and uniformity of the electrolyte membrane. It has good operability and industrialization potential and can adapt to different scale production requirements. (4) The polyether block amide copolymer used in the integrated positive electrode of the present invention has high mechanical strength, which can effectively prevent lithium dendrite penetration and has better compatibility with polyethylene oxide, which can reduce the impedance of the bilayer membrane interface and enhance the stability of the electrolyte bilayer membrane interface. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the preparation process of the Pebax / PEO composite solid-state battery in Example 1; Figure 2The graph shows the performance data of the Pebax / PEO composite solid-state battery obtained in Example 1 during its first charge and discharge cycle. Detailed Implementation

[0031] The technical solution of the present invention will be further described and illustrated below with reference to specific embodiments and accompanying drawings. It should be understood that the specific embodiments described herein are only for the purpose of helping to understand the present invention and are not intended to limit the specific scope of the present invention. Furthermore, the accompanying drawings used herein are merely for better illustrating the content disclosed in the present invention and do not limit the scope of protection. Unless otherwise specified, the raw materials used in the embodiments of the present invention are all commonly used in the art, and the methods used in the embodiments are all conventional methods in the art.

[0032] The positive electrode used in the following examples was prepared by dissolving 80% lithium iron phosphate, 10% carbon black, and 10% PVDF binder in NMP solvent. The resulting slurry was cast onto aluminum foil, and the solvent was evaporated at 80°C. The slurry was then pressed and stamped into sheets with a diameter of 13 mm and a thickness of 20-30 μm, and dried in a vacuum oven at 80°C for 12 hours to remove residual moisture. The mass loading of lithium iron phosphate was approximately 2-3 mg / cm³. 2 .

[0033] The lithium metal anode uses lithium metal with a diameter of 15.6 mm and a thickness of 200~500-300 μm; the PEO was purchased from Maclean and has a relative molecular weight of about 600,000. Example 1

[0034] The preparation method of the Pebax / PEO composite solid-state battery in this embodiment includes the following steps: (1) Pebax1657 and LiTFSi were added to a sealed container at a mass ratio of 3.5:1.0. Solvent (ethanol and water were mixed at a mass ratio of 7:3) was added and the mixture was magnetically stirred at 80°C and 500 rpm for 6 h. Then, it was ultrasonically mixed for 20 min to obtain a homogeneous solution with a mass concentration of 5%. Lithium aluminum titanate phosphate (LATP) of 20% of Pebax1657 was added as filler and stirred evenly. The resulting slurry was cast onto the positive electrode sheet and vacuum-dried at 40°C for 6 h. Then, the temperature was increased to 80°C and dried for 24 h to obtain an integrated positive electrode sheet with a composite film thickness of 40 μm. (2) Polyethylene oxide and LiTFSi were added to a sealed container at a mass ratio of 4.0:1.0. Acetonitrile was added and the mixture was magnetically stirred at 60°C and 500 rpm for 6 hours. Then, it was ultrasonically mixed for 20 minutes to obtain a homogeneous solution with a mass concentration of 5%. Lithium aluminum titanate phosphate (LATP) of 20% PEO mass was added as filler and stirred evenly. The resulting slurry was cast into a polytetrafluoroethylene mold and cast evenly. It was vacuum dried at 60°C for 24 hours to obtain a negative electrode side film with a thickness of 100 μm. (3) The obtained negative electrode side film is covered on the obtained integrated positive electrode sheet, then a lithium metal sheet is stacked on top, and finally pressed at 50 psi for 15s; the preparation process is as follows. Figure 1 As shown. Example 2

[0035] The preparation method of the Pebax / PEO composite solid-state battery in this embodiment includes the following steps: (1) Pebax2533 and LiDFOB were added to a sealed container at a mass ratio of 2.5:1.0. Solvent (ethanol and water were mixed at a mass ratio of 7:3) was added and the mixture was magnetically stirred at 400 rpm for 6 h at 85 °C. Then, it was ultrasonically mixed for 20 min to obtain a homogeneous solution with a mass concentration of 5%. Then, 20% of the mass of Pebax2533 alumina was added as filler and stirred evenly. The resulting slurry was cast onto the positive electrode sheet and vacuum-dried at 45 °C for 6 h. Then, the temperature was increased to 75 °C and dried for 24 h to obtain a positive electrode side film with a composite film thickness of 50 μm. (2) Polyethylene oxide and LiDFOB were added to a sealed container at a mass ratio of 1.5:1.0. Acetonitrile was added and the mixture was magnetically stirred at 70°C and 400 rpm for 6 hours. Then, it was ultrasonically mixed for 20 minutes to obtain a homogeneous solution with a mass concentration of 5%. Alumina with a mass of 20% PEO was added as filler and stirred evenly. The resulting slurry was cast into a polytetrafluoroethylene mold and cast evenly. It was vacuum dried at 70°C for 24 hours to obtain a negative electrode side film with a thickness of 120 μm. (3) The obtained negative electrode side film is covered on the obtained integrated positive electrode sheet, and then a lithium metal sheet is stacked on it. Finally, it is pressed at 50 psi for 15s. Example 3

[0036] The preparation method of the Pebax / PEO composite solid-state battery in this embodiment includes the following steps: (1) Pebax2533 and LiTFSi were added to a sealed container at a mass ratio of 3.5:1.0. Solvent (ethanol and water were mixed at a mass ratio of 7:3) was added and the mixture was magnetically stirred at 400 rpm for 6 h at 85 °C. Then, it was ultrasonically mixed for 20 min to obtain a homogeneous solution with a mass concentration of 5%. Then, 25% alumina of Pebax2533 was added as filler and stirred evenly. The resulting slurry was cast onto the positive electrode sheet and vacuum-dried at 45 °C for 6 h. Then, the temperature was increased to 75 °C and dried for 24 h to obtain an integrated positive electrode sheet with a composite film thickness of 75 μm. (2) Polyethylene oxide and LiDFOB were added to a sealed container at a mass ratio of 2.0:1.0. Acetonitrile was added and the mixture was magnetically stirred at 70°C and 400 rpm for 6 hours. Then, it was ultrasonically mixed for 20 minutes to obtain a homogeneous solution with a mass concentration of 5%. 25% LATP of PEO was added as filler and stirred evenly. The resulting slurry was cast into a polytetrafluoroethylene mold and cast evenly. It was vacuum dried at 70°C for 24 hours to obtain a negative electrode side film with a thickness of 150 μm. (3) The obtained negative electrode side film is covered on the obtained integrated positive electrode sheet, and then a lithium metal sheet is stacked on it. Finally, it is pressed at 50 psi for 15s. Example 4

[0037] The difference between this embodiment and embodiment 1 is that the mass ratio of Pebax1657 to LiTFSi in step (1) is 4.0:1.0, and the mass ratio of polyethylene oxide to LiTFSi in step (2) is 2.5:1.0. Example 5

[0038] The difference between this embodiment and embodiment 1 is that the mass ratio of Pebax1657 to LiTFSi in step (1) is 2.0:1.0, and the mass ratio of polyethylene oxide to LiTFSi in step (2) is 1.25:1.0. Example 6

[0039] The only difference between this embodiment and Embodiment 1 is that the thicknesses of the composite film and the negative electrode side film in the integrated positive electrode sheet are 100 μm and 200 μm, respectively. Comparative Example 1

[0040] The comparative solid-state battery preparation method includes the following steps: (1) Pebax1657 and LiTFSi were added to a sealed container at a mass ratio of 3.5:1.0. Solvent (ethanol and water were mixed at a mass ratio of 7:3) was added and the mixture was magnetically stirred at 80°C and 500 rpm for 6 h. Then, it was ultrasonically mixed for 20 min to obtain a homogeneous solution with a mass concentration of 5%. Lithium aluminum titanate phosphate (LATP) of 20% of Pebax1657 was added as filler and stirred evenly. The resulting slurry was cast onto the positive electrode sheet and vacuum-dried at 40°C for 6 h. Then, the temperature was increased to 80°C and dried for 24 h to obtain an integrated positive electrode sheet with a thickness of 40 μm. (2) A lithium metal sheet is stacked on the resulting integrated positive electrode sheet, and finally pressed at 50 psi for 15s. Comparative Example 2

[0041] The comparative solid-state battery preparation method includes the following steps: (1) Polyethylene oxide and LiTFSi were added to a sealed container at a mass ratio of 4.0:1.0. Acetonitrile was added and the mixture was magnetically stirred at 60°C and 500 rpm for 6 h. Then, it was ultrasonically mixed for 20 min to obtain a homogeneous solution with a mass concentration of 5%. Lithium aluminum titanate phosphate (LATP) of 20% PEO mass was added as a filler and stirred evenly. The resulting slurry was cast onto the positive electrode sheet and vacuum dried at 60°C for 24 h to obtain a negative electrode side film with a thickness of 100 μm. (2) Cover the positive electrode with the obtained negative electrode side film, then stack the lithium metal sheet, and finally press at 50 psi for 15s. Comparative Example 3

[0042] The preparation method of the Pebax / PEO composite solid-state battery in this comparative example includes the following steps: (1) Pebax1657 and LiTFSi were added to a sealed container at a mass ratio of 3.5:1.0. Solvent (ethanol and water were mixed at a mass ratio of 7:3) was added and the mixture was magnetically stirred at 80°C and 500 rpm for 6 h. Then, it was ultrasonically mixed for 20 min to obtain a homogeneous solution with a mass concentration of 5%. Lithium aluminum titanate phosphate (LATP) of 20% of Pebax1657 was added as filler and stirred evenly. The resulting slurry was cast into a polytetrafluoroethylene mold and cast evenly. After vacuum drying at 40°C for 6 h, the temperature was increased to 80°C and dried for 24 h to obtain a positive electrode side film with a thickness of 40 μm. (2) Polyethylene oxide and LiTFSi were added to a sealed container at a mass ratio of 4.0:1.0. Acetonitrile was added and the mixture was magnetically stirred at 60°C and 500 rpm for 6 hours. Then, it was ultrasonically mixed for 20 minutes to obtain a homogeneous solution with a mass concentration of 5%. Lithium aluminum titanate phosphate (LATP) of 20% PEO mass was added as filler and stirred evenly. The resulting slurry was cast into a polytetrafluoroethylene mold and cast evenly. It was vacuum dried at 60°C for 24 hours to obtain a negative electrode side film with a thickness of 100 μm. (3) Stack the obtained positive electrode side film on the positive electrode sheet, and then cover it with the obtained negative electrode side film. Control the temperature of the positive electrode side film to 70°C and the temperature of the negative electrode side film to 30°C. Hot press at 0.5MPa for 70s, then stack the lithium metal sheet, and finally press at 50psi for 15s.

[0043] The Pebax / PEO composite solid-state batteries obtained in the above examples and comparative examples were charged to 3.8V at a constant current of 0.1C and discharged to 2.8V at a constant current of 0.1C. The test results of charging capacity, discharging capacity and impedance are shown in Table 1.

[0044] Table 1 Performance data of Pebax / PEO composite solid-state batteries .

[0045] According to Table 1 and Figure 2 As shown, Examples 1-4 and Example 6 use a bilayer membrane composite as the solid electrolyte, which can better adapt to the high oxidizability of lithium iron phosphate cathode material and the high reducing power of lithium metal anode, broadening the electrochemical window and improving ionic conductivity and energy density of solid-state batteries. In Example 5, the integrated cathode and anode side membranes have a high lithium salt content and low Pebax1657 and PEO content. The increase in lithium salt concentration leads to an increase in the number of separation points in the polymer matrix. Lithium ions will have a strong coordination effect with polar groups on the polymer chain (such as ether oxygen or amide groups in Pebax1657), which restricts the peristalsis of the molecular chain, reduces the ion transport efficiency, and degrades battery performance. Comparative Example 1 only stacks lithium metal sheets on the integrated cathode to obtain a solid-state battery, using a single-layer polymer film as the solid electrolyte. The amide group (-NH-CO-) in Pebax1657 is unstable on the low-voltage lithium anode side and is easily reduced and decomposed, resulting in continuous interfacial reaction. Comparative Example 2 only covers the obtained anode side film on the positive electrode sheet and then stacks lithium metal sheets to obtain a solid-state battery. A single polymer film layer is used as the solid electrolyte. Pure PEO is easily oxidized and decomposed under high voltage due to the ether bonds (COC) on the molecular chain, and has low ionic conductivity, which limits the battery performance. Comparative Example 3 first obtains the positive and negative electrode side films separately, hot-presses to obtain the polymer electrolyte, and then assembles it into a solid-state battery. The contact surface of the two physically stacked prefabricated films is microscopically rough. Even when pressure is applied, there are still micron-sized gaps at the interface. These gaps are non-conductive regions for ions, which leads to increased impedance and decreased battery performance.

[0046] Finally, it should be noted that the specific embodiments described herein are merely illustrative of the spirit of the invention and are not intended to limit the implementation of the invention. Those skilled in the art can make various modifications or additions to the described embodiments or use similar methods to replace them; it is neither necessary nor possible to exemplify all embodiments here. However, these obvious variations or modifications derived from the essential spirit of the invention still fall within the scope of protection of the invention, and interpreting them as any additional limitation would contradict the spirit of the invention.

Claims

1. A Pebax / PEO composite solid-state battery, characterized in that, This includes an integrated positive electrode sheet, a negative electrode side film, and a lithium metal sheet; The integrated positive electrode sheet includes a positive electrode sheet and a composite film layer above the positive electrode sheet; the integrated positive electrode sheet is obtained by dissolving polyether block amide copolymer and lithium salt, adding inorganic filler and stirring evenly, casting the resulting composite slurry onto the positive electrode sheet, and drying it. The negative electrode side membrane is obtained by dissolving polyethylene oxide and lithium salt, adding inorganic filler, stirring evenly, casting, and drying.

2. The Pebax / PEO composite solid-state battery according to claim 1, characterized in that, The thickness of the positive electrode in the integrated positive electrode sheet is 20~30μm, the thickness of the composite film layer is 30~100μm, and / or the thickness of the negative electrode side film is 100~200μm.

3. The Pebax / PEO composite solid-state battery according to claim 1, characterized in that, In the polyether block amide copolymer, the hard segment is one or two of nylon 6 and nylon 12, and the soft segment is one or more of polytetrahydrofuran, polybutanediol, and polypropylene glycol. And / or the lithium salt is one or more of lithium bis(trifluoromethanesulfonyl)imide, lithium bis(difluorosulfonyl)imide, lithium hexafluorophosphate, and lithium difluorooxalateborate. And / or the inorganic filler is one or more of lithium aluminum phosphate titanate, alumina, zeolite imidazole ester framework, and boron nitride.

4. The Pebax / PEO composite solid-state battery according to claim 1, characterized in that, The mass ratio of hard segments to soft segments in polyether block amide copolymers is 1.5~4.0:

1.

5. The Pebax / PEO composite solid-state battery according to claim 1, characterized in that, The Shore D hardness of the polyether block amide copolymer is 20 to 70; and / or the molecular weight of the polyethylene oxide is 600,000 to 1,000,000.

6. The Pebax / PEO composite solid-state battery according to claim 1, characterized in that, The mass ratio of polyether block amide copolymer to lithium salt in the integrated positive electrode is 2.5~8.0:1.0; The mass ratio of polyethylene oxide to lithium salt in the negative electrode side membrane is 1.5~3.0:1.

0.

7. The Pebax / PEO composite solid-state battery according to claim 1, characterized in that, The mass of inorganic filler in the integrated positive electrode is 10-30% of the mass of the polyether block amide copolymer. The mass of inorganic filler in the negative electrode side membrane is 10-30% of the mass of polyethylene oxide.

8. The Pebax / PEO composite solid-state battery according to claim 1, characterized in that, The dissolution temperature of polyether block amide copolymer and lithium salt, as well as polyethylene oxide and lithium salt, is 50~100℃, the stirring speed is 300~800rpm, and the stirring time is 4~8h.

9. The Pebax / PEO composite solid-state battery according to claim 1, characterized in that, When preparing the integrated positive electrode sheet, the drying process involves first pre-drying at 30-50℃ for 5-10 hours, and then drying at 60-80℃ for 20-30 hours; and / or when preparing the negative electrode side film, the drying process involves drying at 50-80℃ for 20-30 hours.

10. A method for preparing a Pebax / PEO composite solid-state battery as described in claim 1, characterized in that, The preparation method involves covering an integrated positive electrode sheet with a negative electrode side film, then stacking lithium metal sheets, and finally pressing them together.

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