Composite solid electrolyte membrane containing compound inorganic filler and preparation method of composite solid electrolyte membrane

Abstract

The invention discloses a composite solid electrolyte membrane containing a compound inorganic filler and a preparation method of the composite solid electrolyte membrane. The electrolyte membrane comprises a polymer porous supporting layer and an inorganic-polymer composite conducting layer arranged in pores and / or the surface of the polymer porous supporting layer, the inorganic filler is a compound of one-dimensional nanowires and two-dimensional nanosheets, the compounding mass ratio is (1: 5)-(5: 1), and the total mass accounts for 30%-60%; and the molar ratio of the LiTFSI to the ether oxygen group (EO) in the PEO is (1: 8)-(1: 20). According to the invention, a three-dimensional continuous ion conduction network is constructed through synergistic compounding of multi-dimensional fillers, so that the defects of easy agglomeration, discontinuous conduction channel, high interface impedance and insufficient mechanical and thermal stability of a single filler in the prior art are overcome; the obtained electrolyte membrane has high ionic conductivity, high lithium ion transference number, low interface impedance and excellent mechanical strength and thermal stability, the preparation process is mature and easy to scale, and the electrolyte membrane is suitable for high-performance solid-state or semi-solid-state lithium batteries.

Description

Technical Field

[0001] This invention relates to the field of solid-state battery technology, specifically to a composite solid-state electrolyte membrane containing compounded inorganic fillers and its preparation method, applicable to solid-state or semi-solid-state lithium batteries. Background Technology

[0002] Solid-state batteries, with their advantages of high energy density and high safety, have become the core development direction of next-generation power batteries. Solid-state electrolytes, as their core components, directly determine the upper limit of battery performance. Currently, mainstream solid-state electrolyte materials have obvious shortcomings: oxide electrolytes have high rigidity and poor contact with the electrode interface; sulfide electrolytes have poor chemical stability and are prone to hydrolysis; polymer electrolytes have low room temperature ionic conductivity and insufficient mechanical strength.

[0003] To address these issues, existing technologies often employ the combination of inorganic fillers and polymers to prepare composite electrolytes. However, key technological bottlenecks remain: single-dimensional inorganic fillers, such as one-dimensional nanowires or two-dimensional nanosheets, cannot simultaneously meet the dual requirements of efficient ion conduction and uniform dispersion. While one-dimensional nanowires can construct long-range conduction channels, they are prone to axial aggregation; while two-dimensional nanosheets can fill local gaps, the discontinuous long-range ion transport paths limit the improvement in ion conductivity. Furthermore, simple physical blends or layered structures still suffer from high interlayer impedance and easy separation after long-term use.

[0004] Therefore, developing a composite solid electrolyte membrane that combines high ionic conductivity, excellent interfacial compatibility, and superior mechanical properties by constructing a synergistic conduction network through multi-dimensional inorganic filler compounding is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0005] The purpose of this invention is to overcome the defects of single-dimensional inorganic filler composite electrolytes in the prior art, such as discontinuous conduction channels and easy agglomeration, and to provide a composite solid electrolyte membrane containing compounded inorganic fillers and its preparation method. Through the synergistic compounding of one-dimensional nanowires and two-dimensional nanosheets, a three-dimensional continuous ion conduction network is constructed, which simultaneously takes into account high ionic conductivity, low interfacial impedance and excellent mechanical properties.

[0006] To achieve the above objectives, the present invention provides a composite solid electrolyte membrane containing a composite inorganic filler, comprising: a polymer porous support layer, and an inorganic-polymer composite conductive layer disposed in the pores and / or on the surface of the polymer porous support layer; wherein the inorganic-polymer composite conductive layer comprises a polymer matrix, a lithium salt, and an inorganic filler uniformly dispersed therein; the inorganic filler is a composite of one-dimensional nanowires and two-dimensional nanosheets.

[0007] Furthermore, the mass ratio of one-dimensional nanowires to two-dimensional nanosheets in the composite is 1:5 to 5:1. When the mass ratio of one-dimensional nanowires to two-dimensional MXene is less than 1:5 (i.e., the proportion of one-dimensional nanowires is <16.7%, and the proportion of MXene is >83.3%), the mass proportion of one-dimensional nanowires is too low (<16.7%), making it difficult for them to form a continuous long-range conductive network in the composite conductive layer. Lithium ions need to repeatedly shuttle between MXene sheets, and the long-range migration resistance increases sharply, manifested as a significant decrease in ionic conductivity and lithium ion transference number. Excessive MXene is prone to stacking and agglomeration due to surface-to-surface interactions, forming thick-layered aggregates. This not only fails to play a dispersing role but also occupies the effective space of the polymer matrix, hindering lithium ion transport. At the same time, the rigidity of MXene sheets is lower than that of one-dimensional nanowires, and excessive filling will reduce the structural support of the composite conductive layer, leading to a decrease in the tensile strength and critical current density of the electrolyte membrane. When the mass ratio of one-dimensional nanowires to two-dimensional MXene is higher than 5:1 (i.e., one-dimensional nanowires account for >83.3%, and MXene accounts for <16.7%), the axial van der Waals force of the excess one-dimensional nanowires is much greater than the steric hindrance effect of MXene. The nanowires will form bundled agglomerates, blocking the lithium-ion conduction path inside the agglomerates. On the outside, due to the uneven distribution of filler, conduction blind zones are formed, resulting in a decrease in ionic conductivity. Void defects are easily formed between the agglomerates and the polymer matrix, which disrupts the interfacial contact between the electrolyte membrane and the electrode, leading to an increase in interfacial impedance and affecting the cycle stability of the battery. Excess one-dimensional nanowires require more intensive dispersion processes (such as ultra-high pressure homogenization and long-term ultrasonication) to achieve initial dispersion, which not only increases production energy consumption and cost but may also cause nanowire structure breakage, resulting in the loss of long-range conduction advantages.

[0008] Furthermore, the one-dimensional nanowires are at least one of lithium lanthanum titanate (LLTO) nanowires or lithium lanthanum zirconate (LLZO) nanowires; the two-dimensional nanosheets are MXene. LLTO / LLZO nanowires, as typical one-dimensional inorganic conductive fillers, possess advantages in high intrinsic lithium-ion conductivity and long-range conductivity. Their linear structure can construct a continuous conductive axis in a polymer matrix, providing a low-resistance long-distance migration path for lithium ions, which is the core support for improving the ionic conductivity and lithium-ion transference number of electrolyte membranes. However, when used alone, one-dimensional nanowires are prone to agglomeration due to axial van der Waals forces, forming bundle-like aggregates, which disrupts the continuity of the conductive channels. MXene, as a two-dimensional layered material, has an ultra-large specific surface area, excellent dispersibility, and good interfacial compatibility. Its layered structure, like molecular-level gaskets, can be inserted into the gaps between one-dimensional nanowires. On the one hand, it inhibits the axial aggregation of nanowires through steric hindrance; on the other hand, it utilizes the functional groups (-OH, -F, etc.) on the surface of the layers to form strong interactions with the polymer matrix, improving the uniformity of filler dispersion. Simultaneously, the microchannels between MXene layers can act as short-range conductive bridges, connecting the conductive axes of adjacent one-dimensional nanowires to construct a seamless conductive network. However, when used alone, two-dimensional MXene layers are prone to surface-to-surface stacking, leading to obstruction of long-range ion migration paths and difficulty in overcoming the bottleneck in ionic conductivity. The essence of compound fillers is to utilize the synergistic effect of one-dimensional long-range conduction and two-dimensional dispersion / bridging. One-dimensional nanowires provide the conductive framework, while two-dimensional nanosheets provide dispersion assurance and gap bridging. The ratio of the two must be precisely matched to avoid the defects of single fillers while maximizing their respective advantages.

[0009] Furthermore, the total mass percentage of the inorganic filler in the inorganic-polymer composite conductive layer is 30%-60%. Ion transport in the composite electrolyte relies on the continuous conductive channels formed by the inorganic filler. When the filler percentage is less than 30%, the filler is isolated and dispersed in the polymer matrix, with excessive spacing between them, failing to form a continuous conductive path. Lithium ions must rely on the chain segment movement of the polymer matrix for migration, making it difficult to achieve high room temperature ionic conductivity. The rigidity and heat resistance of the inorganic filler are significantly superior to those of the polymer matrix. When the filler percentage is less than 30%, its support for the composite conductive layer is insufficient, failing to compensate for the polymer's poor mechanical strength and weak thermal stability, and failing to meet the mechanical stress and temperature environment requirements during battery assembly and cyclic use. The interaction between the inorganic filler and the lithium electrode and polymer matrix can inhibit lithium dendrite growth and improve interfacial compatibility. When the filler percentage is less than 30%, its exposure density on the surface of the composite conductive layer is insufficient, failing to form an effective interfacial protective layer, leading to an increased risk of lithium dendrite penetration and a decrease in battery cycle stability. Inorganic fillers (especially one-dimensional nanowires) are prone to agglomeration due to van der Waals forces, while the polymer matrix has an upper limit on its dispersion capacity for fillers. When the filler content exceeds 60%, it exceeds the dispersion threshold of the polymer matrix, and the filler will form large-scale agglomerates (with particle sizes reaching several micrometers). This not only disrupts the continuity of the conduction channels but also creates dead volumes within the agglomerates, leading to impeded ion transport. When the filler content exceeds 60%, the rigidity of the composite conductive layer is significantly enhanced, while its flexibility is lost, forming rigid contact defects at the electrode interface, resulting in a sharp increase in interfacial impedance.

[0010] Furthermore, the polymer porous support layer is made of at least one of polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP), polyacrylonitrile (PAN), or polyimide (PI), with a porosity of 40%-60%.

[0011] Furthermore, the polymer matrix is ​​polyethylene oxide (PEO), the lithium salt is lithium bis(trifluoromethanesulfonylimide) (LiTFSI), and the molar ratio of LiTFSI to the ether radical (EO) in PEO is 1:8 to 1:20.

[0012] Furthermore, the inorganic-polymer composite conductive layer partially covers the surface of the polymer porous support layer and forms a consistent continuous film layer, with the two forming an integrated composite structure of an interpenetrating network.

[0013] On the other hand, the present invention also provides a method for preparing a composite solid electrolyte membrane containing a composite inorganic filler as described above, comprising the following steps: S1: A porous polymer support layer was prepared using a casting phase inversion method; S2: Weigh out the polymer matrix, one-dimensional nanowires, two-dimensional nanosheets and lithium salt in proportion, disperse them in an organic solvent, and form a uniform composite slurry by vacuum stirring. S3: Introduce the composite slurry into the polymer porous support layer by means of coating, impregnation or injection; S4: The support layer containing the slurry is subjected to hot-press curing treatment. The hot-pressing temperature is 60-100℃, the pressure is 2-10MPa, and the time is 5-15 minutes. The solvent is evaporated and the interlayer is densified to obtain a composite solid electrolyte membrane.

[0014] The present invention also provides a lithium-ion battery, comprising a positive electrode, a negative electrode and an electrolyte disposed therebetween, characterized in that the electrolyte is the aforementioned composite solid electrolyte membrane containing compounded inorganic fillers.

[0015] The beneficial effects of this invention are: (1) Through the synergistic combination of one-dimensional nanowires (LLTO / LLZO) and two-dimensional nanosheets (MXene), the one-dimensional nanowires provide a low-resistance long-range conduction backbone, while the two-dimensional nanosheets fill the gaps and form short-range conduction bridges. The two work together to construct a seamless three-dimensional ion conduction network, completely solving the defects of single one-dimensional filler agglomeration and single two-dimensional filler insufficient long-range conduction. The measured room temperature ion conductivity can reach 4.7 × 10⁻⁶. -4 ~5.3×10 -4 With a flux ratio (S / cm) and a lithium-ion transference number ≥0.69, the efficiency is improved by 15%~39% compared to single-filler systems, meeting the ion transport requirements of high-performance solid-state batteries. A 30%-60% total filler mass ratio ensures the continuity and density of the conductive network, avoiding both conductive blind spots caused by insufficient filler and agglomeration and blockage caused by excessive filler. This results in a stable and low-resistance ion transport path, with a conductivity efficiency decay rate of <10% after long-term cycling.

[0016] (2) The ultra-large specific surface area and surface functional groups (-OH, -F) of MXene can form strong interactions with the polymer matrix and lithium electrode. At the same time, the integrated composite structure (interpenetrating composite conductive layer and porous support layer) eliminates the interlayer gaps, reducing the interfacial impedance between the electrolyte membrane and the electrode to 85~95 Ω·cm. 2 Compared to single-filler systems, this reduces ion interface migration resistance by 12.5% ​​to 30%. The composite conductive layer and the polymer porous support layer form an interpenetrating network, avoiding the risk of separation during long-term use of traditional stacked structures. It can maintain structural integrity during the volume changes of battery charge-discharge cycles, ensuring the stability of the conductive channels and interface contacts.

[0017] (3) The polymer porous support layer (PVDF-HFP / PAN / PI) provides a rigid framework. The rigid network formed by the compounded inorganic fillers works synergistically with the flexible matrix of the polymer matrix to maintain the tensile strength of the electrolyte membrane at 1540~1580 Kgf / cm. 2 The critical current density reaches 1.4~1.6 mA / cm². 2 It can withstand the mechanical stress of cutting and stacking during battery assembly, and suppress lithium dendrite penetration, thus improving battery safety redundancy. The high heat resistance of inorganic fillers (LLTO / LLZO / MXene) combined with the structural stability of the support layer raises the thermal decomposition temperature of the electrolyte membrane to 232~238℃, which is much higher than that of pure polymer electrolytes (about 100℃). It can withstand temperature fluctuations during battery operation (usually <80℃) and avoid the risk of short circuits caused by membrane melting and deformation. Detailed Implementation

[0018] The following examples illustrate specific implementations of the present invention. However, these examples are merely for illustrative purposes and do not limit the scope of the invention in any way.

[0019] Example 1: Preparation of PVDF-HFP porous support layer: 10g PVDF-HFP was dissolved in 90g N,N-dimethylacetamide (DMAc), cast into a film, and then immersed in a deionized water coagulation bath for phase separation. After drying, a porous membrane with a thickness of about 8μm and a porosity of about 50% was obtained. Preparation of composite slurry: 1g PEO, 0.5g LLTO nanowires, 0.5g MXene (composite mass ratio 1:1), and 0.3g LiTFSI were dispersed together in 20g acetonitrile and stirred under planetary vacuum (1000rpm, -0.09MPa) for 2 hours to form a homogeneous slurry; Slurry introduction: The slurry is precisely coated onto the porous support layer, and the wet film thickness is controlled to be 50μm; Hot pressing curing: Hot pressing at 80℃ and 5MPa for 10 minutes yields a composite solid electrolyte membrane with a total thickness of approximately 20μm.

[0020] Example 2: The difference between this embodiment and Embodiment 1 is that the inorganic filler is 0.8g LLZO nanowires and 0.2g MXene (mixed mass ratio 4:1), while the other conditions are the same as in Embodiment 1.

[0021] Example 3: The difference between this embodiment and Embodiment 1 is that the inorganic filler is 0.2g LLTO nanowires and 0.8g MXene (composite mass ratio 1:4), while the other conditions are the same as in Embodiment 1.

[0022] Comparative Example 1 The difference between this comparative example and Example 1 is that the inorganic filler is 0.9g LLTO nanowires and 0.1g MXene (mixed mass ratio 9:1), while the other conditions are the same as in Example 1.

[0023] Comparative Example 2 The difference between this comparative example and Example 1 is that the inorganic filler is 0.1g LLTO nanowires and 0.9g MXene (mixed mass ratio 1:9), while the other conditions are the same as in Example 1.

[0024] Comparative Example 3 The difference between this comparative example and Example 1 is that the inorganic filler is 0.25g LLTO nanowires and 0.25g MXene (the total mass percentage of the inorganic filler in the inorganic-polymer composite conductive layer is 27.78%), and the other conditions are the same as in Example 1.

[0025] Comparative Example 4 The difference between this comparative example and Example 1 is that the inorganic filler is 1.25g LLTO nanowires and 1.25g MXene (the total mass percentage of the inorganic filler in the inorganic-polymer composite conductive layer is 65.79%), and the other conditions are the same as in Example 1.

[0026] Comparative Example 5 The difference between this comparative example and Example 1 is that the inorganic filler is 1g LLTO nanowires, which does not contain MXene, while the other conditions are the same as in Example 1.

[0027] Comparative Example 6 The difference between this comparative example and Example 1 is that the inorganic filler is 1g MXene, and it does not contain LLTO nanowires. All other conditions are the same as in Example 1.

[0028] I. Summary of Experimental Data The composite solid electrolyte membranes prepared in Examples 1-3 and Comparative Examples 1-6 were assembled into Li|electrolyte membrane|Li symmetric batteries, and their core performance was tested at room temperature (25°C). The test items included room temperature ionic conductivity, lithium-ion transport number, critical current density, thermal stability (thermal decomposition temperature), tensile strength, and interfacial impedance (initial value before cycling). The specific data are shown in the table below:

[0029] Note: All tests follow industry standard methods: ionic conductivity is measured using AC impedance spectroscopy (frequency range 10). -1 ~10 6The lithium-ion transference number was determined using the Bruce-Vincent method; the critical current density was determined by constant current polarization test (maximum current density before voltage change); thermal stability was determined by thermogravimetric analysis (TGA, heating rate 10℃ / min, air atmosphere); tensile strength was tested using a universal testing machine (tensile rate 5mm / min); and interfacial impedance was obtained by fitting the AC impedance spectrum of a symmetrical cell.

[0030] Experimental data analysis The compounding ratios of Examples 1-3 (1:1, 4:1, and 1:4) all fall within the design range of 1:5 to 5:1, with the total proportion of inorganic fillers being 50% (within the range of 30%-60%). Test data show that all three exhibit excellent comprehensive performance, with room temperature ionic conductivity all exceeding 4.7 × 10⁻⁶. -4 With a conductivity exceeding S / cm and a lithium-ion transference number ≥0.69, this is significantly superior to comparative examples 5-6 using a single filler. This is because the one-dimensional nanowires (LLTO / LLZO) and two-dimensional nanosheets (MXene) form a three-dimensional continuous conductive network with long-range conductive axes and short-range bridging. The LLTO / LLZO nanowires provide low-resistance long-range paths, while the MXene sheets fill the gaps and inhibit aggregation, resulting in uninterrupted lithium-ion migration and a significant improvement in conductivity. Example 1 (1:1 blend) exhibits the best performance, achieving a conductivity of 5.3 × 10⁻⁶. -4 The S / cm and migration number of 0.73 confirm that the synergistic effect of the two fillers is maximized when they are mixed in equal proportions. Tensile strengths remained between 1540 and 1580 Kgf / cm². 2 The film exhibits thermal stability of 232~238℃, meeting the mechanical stress requirements during battery assembly (resisting cutting and stacking pressure) and tolerating thermal deformation at battery operating temperatures (typically <80℃). This is attributed to two factors: firstly, the 50% filler content forms a rigid framework, compensating for the insufficient mechanical strength and heat resistance of the PEO matrix; secondly, the uniform dispersion of the compound filler avoids localized stress concentration, resulting in more stable mechanical properties of the film. The interfacial impedance is only 85~95Ω·cm. 2 The specific surface area of ​​MXene sheets is much lower than that of single filler systems. This is because the large specific surface area and surface functional groups (-OH, -F) of MXene sheets enhance the interaction with the polymer matrix and lithium electrode, reducing interfacial gaps. At the same time, the integrated composite structure (interpenetrating composite conductive layer and porous support layer) further reduces interlayer impedance, ensuring smooth ion transport at the interface.

[0031] Comparative Example 1 (9:1 blend): The proportion of one-dimensional nanowires was too high (90%), exceeding the upper limit. This caused the nanowires to agglomerate into bundles due to axial van der Waals forces, disrupting the continuity of the conduction channel. As a result, the ionic conductivity decreased to 3.2 × 10⁻⁶. -4The S / cm ratio and lithium-ion transference number are only 0.58; the formation of void defects between the aggregates and the polymer matrix causes the interfacial impedance to soar to 180 Ω·cm. 2 The critical current density drops to 1.0 mA / cm². 2 (Lithium dendrites are easily penetrated). Comparative Example 2 (1:9 blend): The proportion of two-dimensional MXene is too high (90%), and the proportion of one-dimensional nanowires is insufficient (16.7%), making it impossible to form a continuous long-range conductive axis. Lithium ions need to shuttle repeatedly between MXene layers, resulting in a sharp increase in long-range migration resistance and a conductivity of only 2.9 × 10⁻⁶. -4 S / cm; Excess MXene undergoes face-to-face stacking, occupying effective space in the polymer matrix, causing the critical current density to drop to 0.9 mA / cm. 2 The tensile strength decreased to 1380 kgf / cm². 2 It is evident that when the compounding ratio exceeds 1:5 to 5:1, the synergistic effect of the two fillers is lost, and the defects of the single-dimensional filler (agglomeration, insufficient long-range conduction) become dominant, leading to a comprehensive deterioration in performance.

[0032] In Comparative Example 3, the total proportion of inorganic fillers was only 27.78%. The fillers were isolated and dispersed in the polymer matrix, unable to form a continuous ion conduction network. Lithium ions mainly relied on the movement and migration of PEO segments, resulting in a room temperature ionic conductivity of only 1.4 × 10⁻⁶. -4 The tensile strength (S / cm) is significantly lower than in the previous example; simultaneously, the filler's skeletal support is insufficient, failing to compensate for the performance shortcomings of the PEO matrix, resulting in thermal stability dropping to 180°C and tensile strength of only 980 Kgf / cm. 2 The membrane cannot meet the mechanical and temperature requirements for battery assembly and cyclic use; the filler exposure density on the membrane surface is insufficient, failing to form an effective interfacial protective layer, resulting in an interfacial impedance of 150 Ω·cm. 2 The critical current density is only 0.7 mA / cm². 2 The risk of lithium dendrite penetration is extremely high.

[0033] In Comparative Example 4, the total proportion of inorganic filler reached 65.79%, exceeding the dispersion and load-bearing capacity limit of the polymer matrix. This resulted in large-scale agglomeration of the filler (agglomerate particle size reaching 3-5 μm), forming dead volumes, disrupting the continuity of the conduction channels, and reducing the ionic conductivity to 2.7 × 10⁻⁶. -4 S / cm; Excessive filler causes a sharp increase in the rigidity of the composite conductive layer, resulting in a loss of flexibility and the formation of rigid contact defects with the lithium electrode, causing the interfacial impedance to soar to 250 Ω·cm. 2 Although thermal stability (240℃) and tensile strength (1600Kgf / cm) are good. 2While there is a slight improvement, the deterioration in ion conduction and interface compatibility has rendered it unable to meet the practical requirements of batteries. Furthermore, the slurry viscosity reaches 2500 mPa·s, leading to problems such as uneven coating and clogging of mesh during the coating process, resulting in extremely poor process feasibility.

[0034] Comparative Example 5 (single LLTO nanowire), the nanowires are prone to axial aggregation, and there are breaks in the conduction channels, thus the conductivity (4.2 × 10⁻⁶) is low. -4 The S / cm and migration number (0.68) were both lower than those of the example; the interface compatibility was poor, with an interface impedance of 110 Ω·cm. 2 Comparative Example 6 (single MXene), the sheets are prone to surface-to-surface stacking, which obstructs long-range conduction paths and reduces conductivity (3.8 × 10⁻⁶). -4 S / cm), critical current density (1.2 mA / cm) 2 The results were lower than those of the previous examples; it is evident that single-dimensional fillers cannot simultaneously resolve the contradiction between conduction continuity and dispersion uniformity, and their performance is significantly weaker than that of multi-dimensional compound systems, thus confirming the necessity of the compound design of this invention.

Claims

1. A composite solid electrolyte membrane containing a compounded inorganic filler, characterized in that, include: A polymer porous support layer, and an inorganic-polymer composite conductive layer disposed in the pores and / or on the surface of the polymer porous support layer; wherein the inorganic-polymer composite conductive layer comprises a polymer matrix, a lithium salt, and an inorganic filler uniformly dispersed therein; the inorganic filler is a composite of one-dimensional nanowires and two-dimensional nanosheets.

2. The composite solid electrolyte membrane containing compounded inorganic fillers according to claim 1, characterized in that, The mass ratio of one-dimensional nanowires to two-dimensional nanosheets in the compound is 1:5 to 5:

1.

3. The composite solid electrolyte membrane containing compounded inorganic fillers according to claim 1 or 2, characterized in that, The one-dimensional nanowire is at least one of lithium lanthanum titanate (LLTO) nanowire or lithium lanthanum zirconate (LLZO) nanowire; the two-dimensional nanosheet is MXene.

4. The composite solid electrolyte membrane containing compounded inorganic fillers according to claim 1, characterized in that, The inorganic filler accounts for 30%-60% of the total mass of the inorganic-polymer composite conductive layer.

5. The composite solid electrolyte membrane containing compounded inorganic fillers according to claim 1, characterized in that, The polymer porous support layer is made of at least one of polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP), polyacrylonitrile (PAN), or polyimide (PI), with a porosity of 40%-60%.

6. The composite solid electrolyte membrane containing compounded inorganic fillers according to claim 1, characterized in that, The polymer matrix is ​​polyethylene oxide (PEO), the lithium salt is lithium bis(trifluoromethanesulfonylimide) (LiTFSI), and the molar ratio of LiTFSI to ether radical (EO) in PEO is 1:8 to 1:

20.

7. The composite solid electrolyte membrane containing compounded inorganic fillers according to claim 1, characterized in that, The inorganic-polymer composite conductive layer partially covers the surface of the polymer porous support layer and forms a consistent continuous film layer, with the two forming an integrated composite structure of interpenetrating network.

8. A method for preparing a composite solid electrolyte membrane containing compounded inorganic fillers as described in any one of claims 1-7, characterized in that, Includes the following steps: S1: A porous polymer support layer was prepared using a casting phase inversion method; S2: Weigh out the polymer matrix, one-dimensional nanowires, two-dimensional nanosheets and lithium salt in proportion, disperse them in an organic solvent, and form a uniform composite slurry by vacuum stirring. S3: Introduce the composite slurry into the polymer porous support layer by means of coating, impregnation or injection; S4: The support layer containing the slurry is subjected to hot-press curing treatment. The hot-pressing temperature is 60-100℃, the pressure is 2-10MPa, and the time is 5-15 minutes. The solvent is evaporated and the interlayer is densified to obtain a composite solid electrolyte membrane.

9. A lithium-ion battery, comprising a positive electrode, a negative electrode, and an electrolyte disposed therebetween, characterized in that, The electrolyte is a composite solid electrolyte membrane containing compounded inorganic fillers as described in any one of claims 1-7.

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