Solid-state electrolyte membrane, solid-state battery and device

Abstract

The invention provides a solid-state electrolyte membrane, a solid-state battery and a device. The solid electrolyte membrane comprises a sulfide electrolyte material and polymer particles, and the polymer particles are dispersed in the sulfide electrolyte material; based on 100 parts by mass of the total mass of the sulfide electrolyte material and the polymer particles, the mass of the polymer particles is 1-50 parts by weight; the size of more than 90 wt% of the polymer particles is 1-500 [mu] m. After the polymer particles are subjected to compression molding under the condition of 100-500MPa, the polymer particles have the compaction density of more than 95% and the breaking strength of more than 50MPa. The mechanical property of the solid-state electrolyte membrane can be improved to inhibit cracks from extending and penetrating through the solid-state electrolyte membrane, and the problem that lithium dendrites penetrate through the solid-state electrolyte membrane is effectively solved.

Description

[0001] This application is a divisional application based on the invention with application number 2020116439673, application date December 31, 2020, applicant CATL, and invention title "A Solid Electrolyte Membrane, Solid Battery and Device". Technical Field

[0002] This application relates to the field of electrochemical technology, and more specifically, to a solid electrolyte membrane, a solid battery, and a device. Background Technology

[0003] During the charging process of solid-state batteries, the continuous deposition of lithium metal causes a significant expansion of the negative electrode, generating internal expansion stress at the negative electrode-electrolyte interface. Under this stress, sulfide electrolytes are prone to localized cracking. Because traditional sulfide electrolytes, similar to ceramic materials, have poor overall structural toughness, cracks formed at the negative electrode interface can rapidly propagate and eventually penetrate the entire solid electrolyte membrane. Furthermore, due to the lower stress at the cracks, lithium dendrites formed during lithium metal deposition readily grow along the voids created by the cracks, eventually forming physical contact with the positive electrode and causing an internal short circuit in the battery. Summary of the Invention

[0004] The purpose of this application is to provide a solid electrolyte membrane, a solid battery, and a device that improves the mechanical properties of the solid electrolyte membrane to suppress crack propagation through the solid electrolyte membrane, effectively solving the problem of lithium dendrites penetrating the solid electrolyte membrane.

[0005] In a first aspect, this application provides a solid electrolyte membrane, the raw materials of which include sulfide electrolyte material and polymer particles, wherein the polymer particles are dispersed in the sulfide electrolyte material;

[0006] Based on a total mass of 100 parts by mass of sulfide electrolyte material and polymer particles, the mass of polymer particles is 1 to 50 parts by mass.

[0007] The size of polymer particles with a content of 90 wt% or more is 1 to 500 μm, and the size of polymer particles with a content of 35 wt% or more is optionally 5 to 20 μm.

[0008] After being pressed into shape under conditions of 100–500 MPa, the polymer particles have a compaction density of more than 95% and a tensile strength of more than 50 MPa.

[0009] The beneficial effects of the technical solution in this application include:

[0010] In this application, polymer particles are added to a sulfide electrolyte material to obtain a composite brick wall structure in which polymer particles are dispersed within the sulfide electrolyte material. By using polymer particles with specific particle sizes and controlling the polymer particles under certain compression molding conditions to achieve specific compaction density and fracture strength, the amount of polymer particles used, when meeting certain standards, has at least the following effects: Firstly, the polymer particles can effectively improve the toughness of the solid electrolyte membrane, making it less prone to cracking; secondly, cracks generated by stress in the sulfide electrolyte material within the solid electrolyte membrane are blocked by the polymer particles during propagation, effectively preventing defects that penetrate the solid electrolyte membrane due to crack propagation. This effectively suppresses the phenomenon of lithium dendrite growth piercing the solid electrolyte membrane, reducing the risk of internal short circuits in the battery.

[0011] In some exemplary embodiments, more than 99 wt% of the polymer particles have a size of 1 to 500 μm, and more than 40 wt% of the polymer particles may have a size of 5 to 20 μm; optionally, more than 99 wt% of the polymer particles have a size of 5 to 20 μm.

[0012] The beneficial effects of the above technical solution include: the size of the polymer particles is better matched with the average particle size of the sulfide electrolyte material, resulting in higher compaction density of the polymer particles and the sulfide electrolyte material, thus increasing the tensile strength of the solid electrolyte membrane and the number of battery cycles.

[0013] In some exemplary embodiments, the aspect ratio of the polymer particles is within 50, optionally within 25, and more preferably within 20.

[0014] The beneficial effects of the above technical solution include: the upper limit of the aspect ratio of polymer particles is within a certain standard, which can effectively improve the tensile strength and compaction density of solid electrolyte membrane, resulting in higher conductivity of solid electrolyte membrane and higher cycle number of battery.

[0015] In some exemplary embodiments, the polymer particles are selected from one or more of polysaccharide polymers, polyhydrocarbon polymers, rubber polymers, polyamide polymers, and polyester polymers.

[0016] The beneficial effects of the above technical solution include: the above-mentioned specific types of polymer particles have the specific ability to better meet the compaction density and fracture strength requirements of polymer particles under specific pressure conditions, and also have the advantages of abundant sources.

[0017] In some exemplary embodiments, the polymer particles contain polar functional groups selected from one or more of hydroxyl, carboxyl, and cyano groups.

[0018] The beneficial effects of the above technical solution include: the polar groups present in the polymer help to form chemical bonds and interactions with the PS groups (phosphorus-sulfur groups) in the sulfide electrolyte material, so that a chemically compatible interface can be formed between the polymer particles and the sulfide electrolyte material, which is beneficial to improving the two-phase dispersion properties and structural stability in the composite brick wall structure, improving the ionic conductivity and fracture strength of the solid electrolyte, and thus improving the battery capacity and cycle life.

[0019] In some exemplary embodiments, the polymer particles are polysaccharide polymers, which may be one or more of xanthan gum, guar gum, gum arabic, starch, cellulose, glycogen, chitosan, agar, and inulin.

[0020] The beneficial effects of the above-mentioned technical solution include: polysaccharide polymers possess excellent mechanical properties, exhibiting not only high fracture strength but also the ability to form a high-density structure under pressure, resulting in good mechanical compatibility with sulfide electrolytes; their molecular chains also contain numerous polar functional groups such as hydroxyl groups, which can form chemically compatible and stable interfaces with sulfide electrolytes. Furthermore, polysaccharide polymers are abundant in source and inexpensive, further reducing the cost of solid electrolytes and demonstrating excellent application prospects.

[0021] In some exemplary embodiments, the degree of polymerization of the polymer particles is 10 to 5 million, optionally 20 to 2 million.

[0022] The beneficial effects of the above technical solution include: selecting polymer particles with specific polymerization degree requirements so that the polymer particles have suitable mechanical strength, which can effectively improve the overall fracture strength of the solid electrolyte membrane, and at the same time facilitate the formation of a uniform and dense composite solid electrolyte membrane, thereby effectively improving the conductivity of the solid electrolyte membrane, the capacity of the battery, the number of battery cycles, and the energy density of the battery.

[0023] In some exemplary embodiments, the sulfide electrolyte material is selected from Li3PS4 and Li7P3S. 11 Li6PS5Cl and Li 10 GeP2S 12 One or more of them.

[0024] The beneficial effects of the above technical solution include: specific types of sulfide electrolyte materials can better meet the performance requirements, resulting in good conductivity of the solid electrolyte membrane, and the battery has good capacity utilization, cycle count and energy density.

[0025] In some exemplary embodiments, the solid electrolyte membrane further includes a binder; based on 100 parts by mass of the total mass of the sulfide electrolyte material and polymer particles, the mass of the binder is 0.5 to 20 parts by mass, optionally 1 to 10 parts by mass, and more preferably 2 to 5 parts by mass.

[0026] The beneficial effects of the above technical solution include: the addition of binder can improve the overall mechanical properties of the solid electrolyte membrane, which is beneficial to ensuring the ability of the ultrathin solid electrolyte membrane to resist battery electrode deformation, thereby extending the cycle performance of the solid battery. Appropriate binder addition facilitates the formation of ultrathin solid electrolyte membranes with a thickness of less than 50 μm, while ensuring that the solid electrolyte membrane has good electrical conductivity.

[0027] In some exemplary embodiments, the thickness of the solid electrolyte membrane is 20–200 μm.

[0028] The beneficial effects of the above technical solution include: the solid electrolyte membrane has a suitable thickness, and the battery can have both a good number of cycles and energy density.

[0029] In a second aspect, this application provides a solid-state battery that includes a solid electrolyte membrane as provided in the first aspect.

[0030] Thirdly, this application provides an apparatus equipped with a solid-state battery as provided in the second aspect. Attached Figure Description

[0031] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a schematic diagram of the microstructure of the solid electrolyte membrane in the composite brick wall structure provided in the embodiments of this application. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0034] It should be noted that the terms "and / or" in this application, such as "feature 1 and / or feature 2", all refer to the three cases of "feature 1" alone, "feature 2" alone, and "feature 1" plus "feature 2".

[0035] In addition, in the description of this application, unless otherwise stated, "one or more" means two or more; the range of "value a to value b" includes the two endpoints "a" and "b"; "unit of measurement" in "value a to value b + unit of measurement" represents the "unit of measurement" of both "value a" and "value b"; descriptions such as "value c or above" and "value c or less" all refer to the number including value c itself.

[0036] The solid electrolyte membrane, solid battery, and device according to embodiments of this application will be described in detail below.

[0037] In a first aspect, this application provides a solid electrolyte membrane. The solid electrolyte membrane comprises a sulfide electrolyte material and polymer particles, with the polymer particles dispersed in the sulfide electrolyte material. Based on a total mass of 100 parts by weight of the sulfide electrolyte material and polymer particles, the polymer particles have a mass of 1 to 50 parts by weight. The polymer particles, comprising more than 90 wt% (particles accounting for more than 90% of the polymer particles by mass), have a size of 1 to 500 μm. After being pressed and molded under conditions of 100 to 500 MPa, the polymer particles possess a compaction density greater than 95% and a tensile strength greater than 50 MPa.

[0038] In the solid-state electrolyte membrane of this application, polymer particles with a size primarily ranging from 1 to 500 μm are more easily and uniformly dispersed. Furthermore, the size of the polymer particles matches well with the average particle size (5–20 μm) of the sulfide electrolyte material, allowing the solid-state electrolyte membrane to maintain good compaction density. This effectively maintains the interfacial contact and ion transport channels between the sulfide electrolyte material and the polymer particles, contributing to the preservation of good conductivity and high tensile strength, among other electrochemical properties. Simultaneously, solid-state batteries can better balance larger capacity, higher energy density, and more cycle times. If the size distribution range of the polymer particles is too large, resulting in more than 90 wt% of the polymer particles having a size of 1–500 μm, the polymer particles will be difficult to disperse uniformly and will have poor matching with the average particle size of the sulfide electrolyte material, leading to overall battery performance degradation. It should be noted that in the embodiments of this application, the lower limit of the polymer particle size range that meets the specific condition refers to the minimum size among all polymer particles meeting that specific condition, and the upper limit refers to the maximum size among all polymer particles meeting that specific condition.

[0039] Because screening with a double screen allows the majority of particles to be controlled within a suitable particle size range, for example, it can effectively control 95 wt% of particles within the target particle size range. As an example, over 95 wt% of the polymer particles have a size of 1–500 μm, resulting in a larger distribution of polymer particles within the 1–500 μm range.

[0040] Considering that a better match between the size of the polymer particles and the average particle size of the sulfide electrolyte material results in a higher compaction density of the polymer particles and the sulfide electrolyte material, it is possible to better maintain the interfacial contact and ion transport channels between the sulfide electrolyte material particles and the polymer particles, while suppressing the growth of lithium dendrites along the internal pores of the electrolyte, thus leading to higher tensile strength of the solid electrolyte membrane and a higher cycle life of the battery. In the embodiments of this application, the size of the polymer particles may optionally be concentrated in the range of 5–20 μm.

[0041] In some optional embodiments, where more than 90 wt% of the polymer particles have a size of 1 to 500 μm, optionally, more than 35 wt% of the polymer particles have a size of 5 to 20 μm.

[0042] Further, more than 99 wt% of the polymer particles have a size of 1 to 500 μm; optionally, more than 40 wt% of the polymer particles have a size of 5 to 20 μm.

[0043] Furthermore, more than 99 wt% of the polymer particles have a size of 2 to 100 μm; optionally, more than 55 wt% of the polymer particles have a size of 5 to 20 μm.

[0044] As an example, over 99 wt% of the polymer particles have a size of 5–20 μm.

[0045] In some exemplary embodiments, the size of the polymer particles, which are 99 wt% or more, is, for example, but not limited to, a range between any two of 1 μm, 2 μm, 5 μm, 10 μm, 20 μm, 50 μm, 100 μm, 200 μm, and 500 μm.

[0046] As an example, polymer particles of the target size can be obtained by sieving. For instance, to obtain polymer particles with a size of 1–500 μm or more (99 wt%), the polymer particles can be sieved through a 32-mesh sieve, and the undersize can be collected. Then, the undersize can be sieved through a 10,000-mesh sieve, and the oversize can be collected. The oversize is the target particle. To obtain polymer particles with a size of 2–100 μm or more (99 wt%), the polymer particles can be sieved through a 150-mesh sieve, and the undersize can be collected. Then, the undersize can be sieved through a 5,000-mesh sieve, and the oversize is collected. The oversize is the target particle. To obtain polymer particles with a size of 5–20 μm or more (99 wt%), the polymer particles can be sieved through a 600-mesh sieve, and the undersize can be collected. Then, the undersize can be sieved through a 2,000-mesh sieve, and the oversize is collected. The oversize is the target particle.

[0047] Considering that when the polymer particle content is too low, the polymer particles can only be scattered in a portion of the solid electrolyte membrane, resulting in limited improvement in the overall tensile strength of the solid electrolyte membrane, controlling the lower limit of polymer particle content to a certain standard can effectively improve the overall tensile strength of the solid electrolyte membrane, enhance its crack resistance, and thus effectively increase the maximum cycle life of the battery.

[0048] Meanwhile, considering that polymer particles themselves cannot conduct lithium ions, excessively high polymer particle content can significantly impact the ion transport capacity within the solid electrolyte membrane, leading to a substantial decrease in the membrane's conductivity, battery capacity, and energy density. Therefore, controlling the upper limit of polymer particle usage within a certain range can effectively balance the performance requirements of the solid electrolyte membrane's conductivity, battery capacity, and battery energy density.

[0049] In some exemplary embodiments, based on a total mass of 100 parts by mass of the sulfide electrolyte material and polymer particles, and with the polymer particles having a mass of 1 to 50 parts by mass, the mass may further be 5 to 50 parts by mass, or 5 to 35 parts by mass, or 10 to 35 parts by mass, or 10 to 20 parts by mass, for example, but not limited to, any one or any two of the following: 1 part by mass, 2 parts by mass, 5 parts by mass, 10 parts by mass, 15 parts by mass, 20 parts by mass, 25 parts by mass, 30 parts by mass, 35 parts by mass, 40 parts by mass, 45 parts by mass, or 50 parts by mass.

[0050] Meanwhile, the amount of sulfide electrolyte material used affects the conductivity of the solid electrolyte membrane and the battery capacity. Based on a total mass of 100 parts by mass of sulfide electrolyte material and polymer particles, the mass of sulfide electrolyte material should be no less than 50 parts by mass to ensure that the material has suitable conductivity and battery capacity.

[0051] In the embodiments of this application, the compression molding condition of 100-500 MPa is close to the molding pressure of solid electrolyte membranes; as an example, the compression molding pressure can be selected as 200-400 MPa, for example, 300 MPa. The selection of the compaction density of polymer particles under certain compression molding conditions is based on the consideration that densification needs to be achieved by applying external pressure during the preparation of solid electrolyte membranes. Selecting polymer particles that can be compacted under specific pressure conditions can be compatible with the preparation process of sulfide electrolyte materials, reducing the manufacturing cost of the solid electrolyte membrane in the composite system; it can also improve the density of the solid electrolyte membrane in the composite system, reduce porosity generated during processing, improve the ionic conductivity of the solid electrolyte membrane, and simultaneously inhibit the growth of lithium dendrites along the internal pores, thereby improving the composite effect of sulfide electrolyte materials and polymer particles. The selection of the fracture strength of polymer particles under certain compression molding conditions is based on the consideration that when the polymer particles themselves possess a certain mechanical strength, they can effectively maintain a stable geometric shape. When the mechanical strength of polymer particles is too low, they are prone to deformation defects under local stress, making it difficult to effectively suppress crack propagation and thus failing to fully utilize the function of composite brick wall structures in suppressing through-hole defects.

[0052] In this application, a composite brick wall structure in which polymer particles are dispersed in a sulfide electrolyte material is obtained by adding polymer particles to the sulfide electrolyte material. This composite brick wall structure is as follows: Figure 1 As shown, the sulfide electrolyte material constitutes the wall structure, and the polymer particles constitute the brick structure. In this composite system, polymer particles with specific particle sizes are used, and the polymer particles are controlled to have specific compaction density and fracture strength under certain compression molding conditions. Under the combined action of these specific polymer particles and the sulfide electrolyte material: on the one hand, the polymer particles can effectively improve the toughness of the solid electrolyte membrane, making it less prone to cracking; on the other hand, cracks generated by the sulfide electrolyte material under stress in the solid electrolyte membrane are blocked by the polymer particles when they propagate, thus effectively preventing crack propagation and the formation of defects that penetrate the solid electrolyte membrane.

[0053] In the embodiments of this application, the particle size, amount, compaction density, and fracture strength of the polymer particles are controlled under specific conditions, so that the solid electrolyte membrane has high compaction density and fracture strength, thereby effectively suppressing the phenomenon of lithium dendrite growth piercing the solid electrolyte membrane and reducing the risk of internal short circuit in the battery.

[0054] In some alternative embodiments, the solid electrolyte membrane is pressed at 100–500 MPa, optionally at 200–400 MPa, for example at 300 MPa. The compacted density of the solid electrolyte membrane is greater than 79%, or greater than 84%, or greater than 90%, or greater than 95%; and the tensile strength of the solid electrolyte membrane is greater than 40 MPa, or greater than 50 MPa, or greater than 60 MPa, or greater than 70 MPa, or greater than 80 MPa, or greater than 90 MPa, or greater than 100 MPa.

[0055] It should be noted that, in the description of this application, the first material being dispersed in the second material refers to the second material serving as the medium for the discrete distribution of the first material, such that the first material is discretely distributed within the second material.

[0056] Considering that the morphology of polymer particles affects their dispersion in solid electrolyte membranes, as well as their mechanical properties and the interfacial contact between them and sulfide electrolyte materials, selecting polymer particles with specific morphology requirements is beneficial for improving the compaction density and tensile strength of solid electrolyte membranes.

[0057] Studies have found that among the morphological characteristics of polymer particles, the aspect ratio has a significant impact on the compaction density and fracture strength of solid electrolyte membranes. Polymer particles need to reach near-micron-scale sizes to maintain sufficient mechanical strength and effectively suppress lithium dendrite penetration and crack propagation. When the aspect ratio of polymer particles is too large, some areas will inevitably have excessively small particle sizes (nanoscale), making it difficult to effectively suppress crack propagation and improve the fracture strength of the solid electrolyte membrane, which is detrimental to increasing the cycle life of the battery. Furthermore, polymer particles with excessively large aspect ratios are more prone to forming localized entanglement structures, resulting in some residual porosity, which is not conducive to improving the compaction density of the solid electrolyte membrane during pressurization molding, leading to a decrease in the conductivity of the solid electrolyte membrane.

[0058] In some exemplary embodiments, the aspect ratio of the polymer particles should be controlled to be less than 50, optionally less than 25, and more preferably less than 20. The aspect ratio of the polymer particles is, for example, but not limited to, 20, 15, 10, or 5. An excessively large aspect ratio will reduce the overall mechanical strength of the solid electrolyte membrane, and ultimately reduce the cycle performance of the battery.

[0059] In order to better meet the compaction density and fracture strength requirements of polymer particles under specific pressure conditions, in some exemplary embodiments, the polymer particles are selected from one or more of polysaccharide polymers, polyhydrocarbon polymers, rubber polymers, polyamide polymers and polyester polymers.

[0060] The study also found that the polar groups present in the polymer help to form chemical bonds and interactions with the PS groups in the sulfide electrolyte material, enabling the polymer particles and the sulfide electrolyte material to form a chemically compatible interface. This is beneficial to improving the two-phase dispersion properties and structural stability in the composite brick wall structure, improving the ionic conductivity and fracture strength of the solid electrolyte, and thus enhancing the battery's capacity utilization and cycle life.

[0061] For example, the polymer particles contain polar functional groups selected from one or more of hydroxyl, carboxyl, and cyano groups.

[0062] As an example, the polymer particles are polysaccharide polymers, further optionally selected from one or more of xanthan gum, guar gum, gum arabic, starch, cellulose, glycogen, chitosan, agar, and inulin. Polysaccharide polymers possess excellent mechanical properties, exhibiting not only high tensile strength but also the ability to form a high-density structure under pressure, resulting in good mechanical compatibility with sulfide electrolytes. Furthermore, their molecular chains contain numerous polar functional groups such as hydroxyl groups, which can form chemically compatible and stable interfaces with sulfide electrolytes. Simultaneously, they offer advantages such as abundant sources and low cost, further reducing the cost of solid electrolytes and demonstrating excellent application prospects.

[0063] Considering that the degree of polymerization of polymer particles affects their mechanical properties, polymer particles need to have an appropriate degree of polymerization. If the polymerization degree is too low, the polymer molecular chains are short and the texture is soft, resulting in lower mechanical strength. This limits the improvement in the overall fracture strength of the solid electrolyte membrane and makes it difficult to effectively suppress lithium dendrite growth and the propagation of internal electrolyte cracks. Conversely, if the polymerization degree is too high, the mechanical strength is higher. However, research has also found that when the mechanical strength of polymer particles is too high, the mechanical property matching between the polymer particles and the sulfide electrolyte material is poor. This leads to point-to-point contact easily forming between the polymer particles and the sulfide electrolyte material, making it difficult to form good physical contact at the two-phase interface between the sulfide electrolyte material and the polymer particles.

[0064] In some exemplary embodiments, the degree of polymerization of the polymer particles is 100,000 to 5,000,000, or 200,000 to 2,000,000, or 400,000 to 1,000,000, for example, but not limited to, any one or any two of 100,000, 200,000, 400,000, 700,000, 1,000,000, 2,000,000, and 5,000,000.

[0065] When the mechanical strength of the polymer is too high, on the one hand, it is not conducive to the formation of a uniform and dense composite solid electrolyte membrane, and it will also lead to a decrease in the overall mechanical strength of the composite solid electrolyte membrane; on the other hand, it is easy to increase the polarization of the two-phase interface, which will reduce the conductivity of the solid electrolyte membrane, the capacity of the battery, the number of battery cycles, and the energy density of the battery.

[0066] It is understood that the sulfide electrolyte material used in the preparation of the solid electrolyte membrane in this application can be selected from materials known in the art. Considering that the conductivity of the solid electrolyte membrane, as well as the battery's capacity, cycle count, and energy density, will vary due to differences in the properties of the sulfide electrolyte material, optionally, the sulfide electrolyte material is selected from Li3PS4 or Li7P3S. 11 Li6PS5Cl and Li 10 GeP2S 12 One or more of them.

[0067] It is understood that in the solid electrolyte membrane of this application, the solid electrolyte membrane may be composed of the above-mentioned sulfide electrolyte material and polymer particles, and the raw materials of the solid electrolyte membrane may also include additives.

[0068] Research has found that due to the numerous hard contacts between the sulfide electrolyte material and polymer particles required by the aforementioned specific conditions, the solid electrolyte membrane is difficult to deform significantly under the pressure of fabrication. When the battery electrodes expand severely, localized residual stress or uneven stress can occur, leading to a risk of structural damage to the composite brick-wall structure of the solid electrolyte membrane. While reducing the thickness of the solid electrolyte membrane is beneficial for improving battery energy density, experiments have shown that when the solid electrolyte membrane thickness is reduced to a certain level, the battery's cycle performance deteriorates. Therefore, to balance the requirements of energy density and cycle performance, the solid electrolyte membrane needs to have an appropriate thickness.

[0069] In some exemplary embodiments, the thickness of the solid electrolyte membrane is 20–200 μm, at which point the battery can achieve both good cycle count and energy density.

[0070] In an embodiment where the solid electrolyte membrane consists only of the aforementioned sulfide electrolyte material and polymer particles, further research revealed that when the thickness of the solid electrolyte membrane is greater than 100 μm, the number of battery cycles is significantly higher; while when the thickness of the solid electrolyte membrane is less than 100 μm, especially less than 50 μm, the energy density of the battery is significantly higher.

[0071] The study further discovered that adding a binder to the solid electrolyte membrane can improve its deformation resistance under fabrication pressure, thereby better mitigating localized stress caused by electrode volume expansion and maintaining the structural stability of the solid electrolyte membrane. Therefore, the addition of a binder can enhance the overall mechanical properties of the solid electrolyte membrane, which is beneficial for ensuring the ability of ultrathin solid electrolyte membranes with a thickness of less than 50 μm to resist battery electrode deformation, thus extending the cycle life of solid-state batteries.

[0072] In some exemplary embodiments, the solid electrolyte membrane further includes a binder dispersed in the solid electrolyte membrane in a filamentary form.

[0073] Considering the low ionic conductivity of binders and their impact on the film-forming performance of solid electrolyte membranes, an appropriate amount of binder needs to be added. If the amount of binder is too small, it is difficult to form an ultra-thin solid electrolyte membrane; if the amount of binder is too large, the excess binder will cause the surface of the sulfide electrolyte material to be coated with binder, affecting lithium-ion migration at the interface, which in turn leads to a significant reduction in the conductivity of the solid electrolyte membrane, making it unable to meet the conductivity requirements for battery use.

[0074] As an example, based on a total mass of 100 parts by mass of sulfide electrolyte material and polymer particles, the mass of binder is 0.5 to 20 parts by mass, or 1 to 10 parts by mass, or 2 to 5 parts by mass, for example, but not limited to, any one or any two of 0.5 parts by mass, 1 part by mass, 2 parts by mass, 4 parts by mass, 5 parts by mass, 6 parts by mass, 8 parts by mass, and 10 parts by mass.

[0075] In an embodiment where the solid electrolyte membrane also includes the aforementioned amount of binder, further research revealed that when the thickness of the solid electrolyte membrane is above 30 μm, the battery cycle count is significantly higher; while when the thickness of the solid electrolyte membrane is below 100 μm, especially below 50 μm, the battery energy density is significantly higher.

[0076] For example, the thickness of the solid electrolyte membrane is 30 to 50 μm, such as, but not limited to, any one or any two of 30 μm, 35 μm, 40 μm, 45 μm and 50 μm. In this case, the solid electrolyte membrane is ultra-thin and has a large number of cycles and a high energy density.

[0077] It is understood that the binder in the solid electrolyte membrane of this application can be selected from materials known in the art. Considering that the structure and morphology of the binder will affect the dispersion state of the materials inside the solid electrolyte membrane, thereby affecting the mechanical and electrochemical performance of the solid battery, the binder may optionally be selected from one or more of polyethylene, polyethylene oxide, polyvinylidene fluoride, polypropylene, polyisobutylene, styrene-butadiene rubber and nitrile rubber.

[0078] Furthermore, the solid electrolyte membrane provided in this application embodiment can be prepared using methods known in the art. As an example, in an embodiment where the solid electrolyte membrane is composed of sulfide electrolyte material and polymer particles, the solid electrolyte membrane is prepared using a dry process; in an embodiment where the solid electrolyte membrane is composed of sulfide electrolyte material, polymer particles, and a binder, the solid electrolyte membrane is prepared using a wet process.

[0079] In some exemplary embodiments, the dry process includes: mixing a sulfide electrolyte material and polymer particles to obtain a composite raw material powder; and pressing the composite raw material powder into shape at a specific operating pressure. The operating pressure may optionally be 100–500 MPa, or 200–400 MPa, for example, 300 MPa.

[0080] In some exemplary embodiments, the wet process includes: mixing a sulfide electrolyte material and polymer particles to obtain an electrolyte powder; dissolving a binder in an organic solvent to obtain a binder solution; dispersing the electrolyte powder in the binder solution to obtain a composite raw material dispersion slurry; coating the composite raw material dispersion slurry onto a substrate to form a coating of a specific thickness; and then drying the coating by vacuum heat treatment.

[0081] In the wet process, the binder is soluble in the organic solvent, while the sulfide electrolyte material and polymer particles are insoluble in the organic solvent, allowing the binder, sulfide electrolyte material and polymer particles to each play an effective role.

[0082] Optionally, the organic solvent is selected from one or more of toluene, xylene, trimethylbenzene, n-heptane, cyclohexane, ethyl acetate, and butyl butyrate.

[0083] As an example, the organic solvent is one or more of toluene, xylene, or trimethylbenzene, the binder is styrene-butadiene rubber and / or polyisobutylene, and the polymer particles are xanthan gum and / or guar gum.

[0084] As another example, the organic solvent is ethyl acetate and / or butyl butyrate, the binder is polyethylene oxide and / or polyvinylidene fluoride, and the polymer particles are cellulose and / or chitosan.

[0085] In a second aspect, this application provides a solid-state battery that includes a solid electrolyte membrane as provided in the first aspect.

[0086] It is understood that, apart from the solid electrolyte membrane being different from membranes known in the art, the other materials and structures of the solid-state battery provided in this application embodiment can refer to the configuration methods known in the art, and the preparation of the solid-state battery can also be carried out with reference to the methods known in the art.

[0087] As an example, the positive electrode material in a solid-state battery includes a positive electrode active material, a conductive agent, and a second binder. The positive electrode active material may optionally be one or more of lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, or lithium phosphates with an olivine structure; furthermore, the positive electrode active material may be LiCoO2, LiNiO2, LiMnO2, LiMn2O4, Li6PS5Cl, or LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2(NCM333), LiNi 0.5 Co 0.2 Mn 0.3 O2(NCM523), LiNi 0.6 Co 0.2 Mn 0.2 O2(NCM622), LiNi 0.8 Co 0.1 Mn 0.1 O2(NCM811), LiNi 0.85 Co 0.15 Al 0.05 One or more of O2, LiFePO4 (LFP), and LiMnPO4. The conductive agent may optionally be one or more of acetylene black, conductive carbon black, carbon fiber, carbon nanotubes, and Ketjen black. The second binder may optionally be one or more of polyvinylidene fluoride and polyvinylidene fluoride-modified (e.g., modified with carboxylic acid, acrylic acid, acrylonitrile, etc.) derivatives.

[0088] In some embodiments, the solid-state battery provided in this application can be assembled into a battery module. The number of solid-state batteries contained in the battery module can be multiple, and the specific number can be adjusted according to the application scenario and capacity requirements of the battery module.

[0089] The aforementioned battery modules can also be assembled into battery packs, and the number of battery modules contained in a battery pack can be adjusted according to the application scenario and capacity requirements of the battery pack.

[0090] Thirdly, this application provides a device equipped with a solid-state battery as provided in the second aspect, the solid-state battery providing power to the device.

[0091] In the embodiments of this application, the device may be, but is not limited to, mobile communication terminals (such as mobile phones, laptops, tablets, POS machines, and in-vehicle computers), electric vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships, satellites, and energy storage systems.

[0092] Understandably, the device can be configured with solid-state batteries, battery modules, or battery packs depending on the user's needs.

[0093] The features and performance of this application will be further described in detail below with reference to the embodiments.

[0094] The solid-state batteries of each embodiment and comparative example were prepared and tested according to the following methods.

[0095] I. Solid-state battery fabrication

[0096] (1) Preparation of solid electrolyte membranes

[0097] The examples without binders use a dry process, while the examples with binders use a wet process.

[0098] Dry processes include:

[0099] S11. Polymer powder is screened through a sieve with a specific mesh size to obtain polymer particles of a specific size.

[0100] S12. The polymer particles and sulfide electrolyte material powder obtained in step S11 are mixed in a specific mass ratio to achieve dry pre-dispersion and obtain pre-dispersed powder.

[0101] S13. The pre-dispersed powder obtained in step S12 is uniformly dispersed by ball milling to obtain composite raw material powder.

[0102] S14. Press the composite raw material powder obtained in step S13 into a solid electrolyte membrane of a specific thickness by operating pressure of 300 MPa.

[0103] Wet processes include:

[0104] S21. The polymer is screened through a sieve with a specific mesh size to obtain polymer particles of a specific size.

[0105] S22. The polymer particles and sulfide electrolyte material powder obtained in step S21 are mixed in a specific mass ratio to achieve dry pre-dispersion and obtain pre-dispersed powder.

[0106] S23. Dissolve a specific mass fraction of the adhesive in an organic solvent to form a uniformly dispersed adhesive solution.

[0107] S24. Mix the pre-dispersed powder obtained in step S22 and the binder solution obtained in step S23 in a certain proportion, and disperse them by ball milling to form a uniform composite electrolyte slurry.

[0108] S25. The composite electrolyte slurry from step S24 is coated onto the substrate. The thickness of the coated electrolyte slurry layer is controlled by changing the size of the squeegee. The coated slurry is then dried by vacuum heat treatment to obtain a solid electrolyte film of a specific thickness.

[0109] (2) Preparation of positive electrode sheet

[0110] S31. The positive electrode active material LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2, Li6PS5Cl electrolyte material, conductive agent Super-P, and styrene-butadiene rubber binder are mixed in a mass ratio of 70:24:3:3 to obtain a mixture.

[0111] S32. Add the mixture obtained in step S31 to toluene solvent and stir under vacuum until the system is homogeneous to obtain the positive electrode slurry.

[0112] S33. The positive electrode slurry obtained in step S32 is uniformly coated on both surfaces of the positive electrode current collector aluminum foil, dried at room temperature, and then transferred to an oven for further drying. After cold pressing and slitting, the positive electrode sheet is obtained.

[0113] (3) Preparation of negative electrode sheet

[0114] The lithium foil is rolled and attached to the two surfaces of the negative electrode current collector copper foil, and then cut to obtain the negative electrode sheet.

[0115] (4) Fabrication of the overall battery

[0116] The positive electrode sheet, solid electrolyte membrane, and lithium metal negative electrode prepared by the above method are stacked in sequence and pressed under 300 MPa to prepare an all-solid-state lithium metal battery.

[0117] II. Performance Parameter Testing

[0118] Regarding the testing of raw materials:

[0119] (1) Polymer particle size test: Polymer particles were uniformly dispersed on the surface of the conductive tape, and polymer particle samples in more than three regions were observed using a scanning electron microscope. The average size of the polymer particle sample was based on the statistical results of the particle size of no less than 50 polymer particles.

[0120] Regarding product testing:

[0121] (2) Conductivity Test: The solid electrolyte membrane was pressed into a disc under a pressure of 300 MPa, and the ohmic impedance of the electrolyte disc was measured using a Chenhua electrochemical workstation. During the test, the ambient temperature was 25℃, the frequency range was 1Hz~1MHz, and the perturbation signal was 5mV. Based on the impedance, thickness, and area of ​​the electrolyte disc, the ionic conductivity was calculated.

[0122] (3) Compaction density test: Solid electrolyte membrane or polymer particles are pressed into discs under a pressure of 300 MPa, and the compaction porosity w of the electrolyte discs is measured using a true density meter. Wherein, the compaction density is 1-w.

[0123] (4) Fracture strength test: The material was pressed into a disc under a pressure of 300 MPa. The stress change of the disc sample during fracture under probe pressure was measured using a tensile testing machine. Based on the fracture limit stress F, sample thickness d, sample diameter R, and sample support spacing s, the corresponding fracture strength E was calculated.

[0124] (5) Maximum tensile strain test: The solid electrolyte membrane was pressed into a strip sample under a pressure of 300 MPa, and the deformation of the strip sample under tensile stress on both sides was measured using a tensile testing machine. The ratio of the deformation x when the sample breaks to the initial length L of the sample is the maximum tensile strain, which is x / L.

[0125] (6) Capacity Performance Test: The capacity performance of the solid-state battery was measured using a Blue Electric Tester. During the test, the operating temperature was 25℃, the charge / discharge rate was 0.1C, and the cutoff voltage was 2.8~4.2V.

[0126] (7) Cyclic performance test: The solid-state battery charge-discharge cycle capacity was measured using a Blue Electric tester. During the test, the operating temperature was 25℃, the charge-discharge rate was 0.1C, and the cutoff voltage was 2.8~4.2V. The maximum number of cycles was determined by the number of cycles when the battery experienced a short circuit or the cycle capacity was less than 50% of the first cycle capacity.

[0127] (8) Energy density test: The energy released by the solid-state battery during the first charge and discharge cycle was measured and recorded using a Blue Electric Tester. The energy density was then calculated by dividing the energy by the weight of the battery cell, with the unit being Wh / kg. During the test, the operating temperature was 25℃, the charge / discharge rate was 0.1C, and the cutoff voltage was 2.8~4.2V.

[0128] The composition of the solid electrolyte membrane in the solid-state battery is shown in Table 1. The mass fractions of the sulfide electrolyte material, polymer, and binder are calculated based on 100 parts by mass of the total mass of the sulfide electrolyte material and polymer particles, hereinafter referred to as converted mass fractions. The performance test results of the solid-state battery are shown in Table 2, as follows:

[0129] Table 1.1 Composition of solid electrolyte membranes in each embodiment and comparative example

[0130]

[0131]

[0132]

[0133]

[0134] Table 2.1 Performance test results of solid-state batteries in each embodiment and comparative example

[0135]

[0136]

[0137]

[0138] The only difference between Examples 1-4 and Comparative Example 1 is the size distribution of the polymer particles. Examples 1-4 satisfy the requirement that over 90 wt% of the polymer particles have a size of 1-500 μm, while Comparative Example 1 does not satisfy this requirement (20 wt% of the polymer particles are outside the 1-500 μm range). A comparison between Examples 1-4 and Comparative Example 1 shows that the solid electrolyte membranes of Examples 1-4 have higher conductivity and tensile strength, and the battery cycle count is significantly improved. A comparison between Examples 1-4 shows that when the polymer particles are concentrated in the 5-20 μm range, the conductivity and tensile strength of the solid electrolyte membrane, as well as the battery cycle count, can be further improved. In particular, in Example 4, when over 99 wt% of the polymer particles have a size of 5-20 μm, the conductivity and tensile strength of the solid electrolyte membrane, as well as the battery cycle count, are all significantly improved.

[0139] The only difference between Examples 4-9 and Comparative Examples 2-3 is the content of polymer particles. A comparison of Examples 4-9 and Comparative Examples 2-3 shows that the content of polymer particles has a significant impact on the conductivity of the electrolyte membrane, the battery capacity, cycle count, and energy density. In Examples 4-9, the polymer particle content ranges from 1 to 50 parts by weight, resulting in higher electrolyte membrane conductivity, battery capacity, cycle count, and energy density. In Comparative Example 2, the polymer particle content is less than 1 part by weight, leading to lower tensile strength of the solid electrolyte membrane and lower cycle count. In Comparative Example 3, the polymer particle content is greater than 50 parts by weight, resulting in lower conductivity and energy density of the solid electrolyte membrane. A comparison of Examples 4-9 shows that when the polymer particle content increases from 1 part to 20 parts by weight, the battery cycle count significantly increases while maintaining high solid electrolyte membrane conductivity and battery capacity. Specifically, a polymer particle content of 5 parts by weight or more, especially 10 parts by weight or more, ensures a good number of battery cycles. When the mass fraction of polymer particles decreased from 50% to 35%, the electrolyte membrane conductivity and battery capacity significantly improved while maintaining a high number of battery cycles. Conversely, when the mass fraction of polymer particles decreased from 35% to 20%, both the solid electrolyte membrane conductivity and battery capacity significantly improved, and the number of battery cycles also significantly increased.

[0140] The only difference between Examples 4 and Examples 10-16 is the degree of polymerization of the polymer particles. A comparison of Examples 4 and Examples 10-16 shows that the degree of polymerization of the polymer particles has a significant impact on the compaction density and tensile strength of the polymer particles after compaction, and therefore significantly affects the conductivity and tensile strength of the solid electrolyte membrane, as well as the battery's capacity utilization, cycle count, and energy density. In Example 10, the degree of polymerization of the polymer particles was less than 100,000, resulting in lower tensile strength after compaction, which significantly reduced the tensile strength of the solid electrolyte membrane and the battery's cycle count. In Example 16, the degree of polymerization of the polymer particles was greater than 5 million, resulting in lower tensile strength after compaction, which also significantly reduced the conductivity and tensile strength of the solid electrolyte membrane, as well as the battery's capacity utilization, cycle count, and energy density.

[0141] The only difference between Example 4 and Examples 17-19 is the type of sulfide electrolyte material. A comparison of Examples 4 and Examples 17-19 shows that in this application, the sulfide electrolyte material used is Li6PS5Cl, Li3PS4, or Li7P3S. 11 and Li 10 GeP2S 12 At that time, the battery showed better performance in terms of capacity utilization, cycle count, and energy density.

[0142] The only difference between Examples 4, Examples 20-27, and Comparative Examples 4-7 is the type of polymer particles. In Comparative Examples 4-5, the tensile strength of the polymer particles after compression molding did not meet the condition of being higher than 50 MPa. A comparison between Examples 4 and Comparative Examples 4-5 shows that the conductivity and tensile strength of the solid electrolyte membrane in Example 4 are significantly improved, resulting in higher battery capacity and energy density, and a significantly increased number of battery cycles. In Comparative Examples 6-7, the compaction density of the polymer particles after compression molding did not meet the condition of being greater than 95%. The conductivity and tensile strength of the solid electrolyte membrane in Example 4 are significantly improved, resulting in significantly improved battery capacity, number of cycles, and energy density. A comparison between Examples 4 and Examples 20-27 shows that when the polymer particles are polysaccharide polymers, polyhydrocarbon polymers, rubber polymers, polyamide polymers, and polyester polymers, the battery exhibits better performance in terms of capacity, number of cycles, and energy density. Among them, when the polymer particles contain polar functional groups, the battery capacity and cycle life can be better improved compared with those without polar functional groups; especially when the polymer is a sugar polymer, the solid electrolyte membrane has better conductivity and tensile strength, resulting in significantly better battery performance in terms of capacity, cycle number and energy density.

[0143] The only difference between Example 4 and Examples 28-31 is the thickness of the solid electrolyte membrane. A comparison of Examples 4 and Examples 28-31 shows that when the solid electrolyte membrane consists only of sulfide electrolyte material and polymer particles, a solid electrolyte membrane thickness of 100 μm or more results in a significantly higher battery cycle count; while a solid electrolyte membrane thickness of less than 100 μm, especially less than 50 μm, results in a significantly higher battery energy density.

[0144] The only difference between Examples 4 and Examples 32-36 is the aspect ratio of the polymer particles. A comparison of Examples 4 and Examples 32-36 shows that when the solid electrolyte membrane consists only of sulfide electrolyte material and polymer particles, in Examples 4 and 32-35, controlling the aspect ratio of the polymer particles to within 50, and further to within 25, especially within 20, results in better capacity utilization, cycle count, and energy density. In Example 36, the aspect ratio of the polymer particles exceeds 50, and the cycle count of the battery is significantly reduced.

[0145] The only difference between Example 4 and Comparative Example 8 is whether or not the solid electrolyte membrane contains polymer particles. The only difference between Example 29 and Comparative Example 9 is whether or not the solid electrolyte membrane contains polymer particles. The only difference between Example 17 and Comparative Example 10 is whether or not the solid electrolyte membrane contains polymer particles. The only difference between Example 18 and Comparative Example 11 is whether or not the solid electrolyte membrane contains polymer particles. The only difference between Example 19 and Comparative Example 12 is whether or not the solid electrolyte membrane contains polymer particles. Through the comparison of Example 4 and Comparative Example 8, and Example 29 and Comparative Example 9, it can be seen that when using solid electrolyte membranes of different thicknesses, and using only sulfide electrolyte material as the raw material for the solid electrolyte membrane, although the battery can achieve good capacity performance and energy density, the cycle life performance of the battery is significantly reduced. Based on the comparisons of Example 4 with Comparative Example 8, Example 17 with Comparative Example 10, Example 18 with Comparative Example 11, and Example 19 with Comparative Example 12, it can be seen that when different sulfide electrolyte materials are used in the solid electrolyte membrane, when only sulfide electrolyte materials are used as the raw material for the solid electrolyte membrane, although the battery can achieve better capacity performance and energy density, the cycle life performance of the battery is significantly reduced.

[0146] Table 1.2 Composition of solid electrolyte membranes in each embodiment and comparative example

[0147]

[0148]

[0149]

[0150] Table 2.2 Performance test results of solid-state batteries in each embodiment and comparative example

[0151]

[0152]

[0153] The only difference between Examples 29 and Examples 37-44 is that the solid electrolyte membranes in Examples 37-44 also include a binder, and the amount of binder used in Examples 37-44 differs. A comparison of Examples 29 and Examples 37-44 shows that appropriately adding a binder to the solid electrolyte membrane is beneficial for increasing the battery's cycle count. A comparison of Examples 37-44 also shows that when the binder's mass fraction is less than 0.5 parts, the battery's cycle count is low; when the binder's mass fraction exceeds 20 parts, the solid electrolyte membrane's conductivity is extremely low, resulting in low battery capacity utilization, cycle count, and energy density. Conversely, when the binder's mass fraction is more than 1 part, especially more than 2 parts, the battery's cycle count is high; when the binder's mass fraction is less than 10 parts, especially less than 5 parts, the solid electrolyte membrane maintains good conductivity, and the battery exhibits high energy utilization.

[0154] The only difference between Examples 41 and Examples 50-52 is the thickness of the solid electrolyte membrane. A comparison of Examples 41 and Examples 50-52 shows that when the solid electrolyte membrane also includes a binder, a thickness of 30 μm or more results in a significantly higher battery cycle count. Conversely, a thickness of less than 100 μm, especially less than 50 μm, leads to a significantly higher energy density. However, a thickness less than 20 μm results in an excessively low cycle count. A solid electrolyte membrane thickness of 20-200 μm, particularly 30-50 μm, allows for a good balance between cycle count and energy density.

[0155] The only difference between Example 41 and Examples 53-57 is the aspect ratio of the polymer particles. A comparison of Examples 41 and Examples 53-57 shows that, when the solid electrolyte membrane also includes a binder, in Examples 49 and 53-56, controlling the aspect ratio of the polymer particles to below 50, and further below 25, especially below 20, resulted in better capacity utilization, cycle count, and energy density. In Example 57, the aspect ratio of the polymer particles exceeded 50, and the cycle count of the battery significantly decreased.

[0156] The only difference between Example 41 and Comparative Example 13 is whether or not the solid electrolyte membrane contains polymer particles. The only difference between Example 49 and Comparative Example 14 is whether or not the solid electrolyte membrane contains polymer particles. The only difference between Comparative Example 13 and Comparative Example 15 is the content of binder in the solid electrolyte membrane, and the only difference between Comparative Example 14 and Comparative Example 16 is the content of binder in the solid electrolyte membrane. Through the comparisons of Example 41 and Comparative Example 13, and Example 49 and Comparative Example 14, it can be seen that when using solid electrolyte membranes of different thicknesses without adding polymer particles, although adding binder to the solid electrolyte membrane can increase the maximum tensile strain, the tensile strength of the solid electrolyte membrane and the cycle life performance of the battery both decrease significantly. By comparing Comparative Examples 13 and 15, and Comparative Examples 14 and 16, it can be seen that even if the amount of binder in the solid electrolyte membrane is increased without adding polymer particles, although the binder added to the solid electrolyte membrane can increase the maximum tensile strain of the solid electrolyte membrane, the tensile strength of the solid electrolyte membrane and the cycle life performance of the battery cannot be significantly improved.

[0157] The embodiments described above are some, but not all, of the embodiments of this application. The detailed description of the embodiments of this application is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

Claims

1. A solid-state electrolyte membrane, characterized by, The solid-state electrolyte film includes a sulfide electrolyte material and polymer particles dispersed in the sulfide electrolyte material; The mass of the polymer particles is 1-50 parts by mass based on 100 parts by mass of the total mass of the sulfide electrolyte material and the polymer particles; 90 wt% or more of the polymer particles have a size of 1-500 μm, and 35 wt% or more of the polymer particles have a size of 5-20 μm; The polymer particles have a compaction density of greater than 95% and a breaking strength of higher than 50 MPa after being compression molded under a pressure of 100-500 MPa; The polymer particles contain a polar functional group, which includes one or more of a hydroxyl group, a carboxyl group, and a cyano group.

2. The solid-state electrolyte film of claim 1, wherein, 99 wt% or more of the polymer particles have a size of 1-500 μm, and 40 wt% or more of the polymer particles have a size of 5-20 μm.

3. The solid-state electrolyte film of claim 2, wherein, 99 wt% or more of the polymer particles have a size of 5-20 μm.

4. The solid-state electrolyte film of claim 1, wherein, The polymer particles have an aspect ratio of 50 or less.

5. The solid-state electrolyte film of claim 4, wherein, The polymer particles have an aspect ratio of 25 or less.

6. The solid-state electrolyte film of claim 4, wherein, The polymer particles have an aspect ratio of 20 or less.

7. The solid-state electrolyte film of claim 1, wherein, The polymer particles are selected from one or more of a polysaccharide polymer, a polyhydrocarbon polymer, a rubber polymer, a polyamide polymer, and a polyester polymer.

8. The solid-state electrolyte film of claim 1, wherein, The polymer particles are a polysaccharide polymer.

9. The solid-state electrolyte film of claim 8, wherein, The polysaccharide polymer is one or more of xanthan gum, guar gum, gum arabic, starch, cellulose, glycogen, chitin, agar, and inulin.

10. The solid-state electrolyte film of any one of claims 1-9, wherein, The polymer particles have a degree of polymerization of 10-5 million.

11. The solid-state electrolyte film of claim 10, wherein, The polymer particles have a degree of polymerization of 20-20 million.

12. The solid-state electrolyte film of claim 1, wherein, The sulfide electrolyte material is selected from one or more of Li3PS4, Li7P3S 11 6, Li6PS5Cl and Li 10 GeP2S 12 6.

13. The solid-state electrolyte film of claim 1, wherein, The solid-state electrolyte film further includes a binder; the mass of the binder is 0.5-20 parts by mass based on 100 parts by mass of the total mass of the sulfide electrolyte material and the polymer particles.

14. The solid-state electrolyte film of claim 13, wherein, The mass of the binder is 1-10 parts by mass.

15. The solid-state electrolyte film of claim 13, wherein, The mass of the binder is 2-5 parts by mass.

16. The solid-state electrolyte film of claim 1 or 13, wherein, The solid-state electrolyte film has a thickness of 20-200 μm.

17. A solid state battery, characterized by The solid-state battery includes the solid-state electrolyte film according to any one of claims 1-16.

18. An apparatus, comprising: The solid-state battery is assembled according to claim 17.

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