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

Abstract

The application provides a solid electrolyte film, a solid battery and a device. The solid electrolyte film comprises a sulfide electrolyte material and polymer particles, the polymer particles are dispersed in the sulfide electrolyte material; based on 100 parts by mass of 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 pressed into shape under the condition of 100-500 MPa, the polymer particles have a compaction density greater than 95% and a breaking strength higher than 50 MPa. The mechanical properties of the solid electrolyte film can be improved to inhibit crack propagation through the solid electrolyte film, and the problem that lithium dendrites penetrate through the solid electrolyte film is effectively solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electrochemistry, in particular to a solid-state electrolyte film, a solid-state battery and a device. BACKGROUND

[0002] During the charging process of the solid-state battery, the continuous deposition of lithium metal leads to a huge volume expansion of the negative electrode, and at this time, internal expansion stress is generated at the negative electrode-electrolyte interface. Under the action of stress, the sulfide electrolyte is prone to local cracking. Since the traditional sulfide electrolyte is similar to ceramic materials, the overall structure has poor toughness, and the cracks formed at the negative electrode interface will quickly expand until the entire solid-state electrolyte film is penetrated. Since the stress at the crack is low, lithium dendrites formed during the lithium metal deposition process are extremely easy to grow along the gap formed at the crack, and eventually form physical contact with the positive electrode, resulting in internal short circuit of the battery. SUMMARY

[0003] The purpose of the present application is to provide a solid-state electrolyte film, a solid-state battery and a device, to improve the mechanical properties of the solid-state electrolyte film to inhibit crack propagation through the solid-state electrolyte film, and effectively solve the problem of lithium dendrites penetrating the solid-state electrolyte film.

[0004] In a first aspect, the present application provides a solid-state electrolyte film, the raw materials of which include a sulfide electrolyte material and polymer particles, and the polymer particles are dispersed in the sulfide electrolyte material.

[0005] 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 mass.

[0006] The size of 90wt% or more of the polymer particles is 1-500μm, and the size of 35wt% or more of the polymer particles can be selected to be 5-20μm.

[0007] After the polymer particles are pressed into shape under the condition of 100-500MPa, they have a compaction density of greater than 95% and a breaking strength of higher than 50MPa.

[0008] The beneficial effects of the technical solution of the present application include:

[0009] In the present application, by adding polymer particles into the sulfide electrolyte material, a composite brick wall structure is obtained in which the polymer particles are dispersed in the sulfide electrolyte material. Polymer particles with a specific particle size are used, and the polymer particles are adjusted to have a specific compaction density and fracture strength under certain pressing conditions, so that the polymer particle dosage at least has the following effects under certain standards: on the one hand, the polymer particles can effectively improve the toughness of the solid-state electrolyte film, making the solid-state electrolyte film less likely to crack; on the other hand, the cracks generated by the stress of the sulfide electrolyte material in the solid-state electrolyte film will be blocked by the polymer particles when they expand, thereby effectively avoiding the formation of defects that penetrate the solid-state electrolyte film due to crack expansion. Further, the phenomenon of lithium dendrite growth piercing the solid-state electrolyte film is effectively inhibited, and the risk of short circuit in the battery is reduced.

[0010] In some exemplary embodiments, the size of 99wt% or more of the polymer particles is 1-500μm, and the size of 40wt% or more of the polymer particles can be selected to be 5-20μm; alternatively, the size of 99wt% or more of the polymer particles is 5-20μm.

[0011] The beneficial effects of the above technical solutions include: the size of the polymer particles is better matched with the average particle size of the sulfide electrolyte material, so that the compaction density of the polymer particles and the sulfide electrolyte material is higher, and therefore the fracture strength of the solid-state electrolyte film and the cycle number of the battery are higher.

[0012] In some exemplary embodiments, the aspect ratio of the polymer particles is within 50, alternatively within 25, and more alternatively within 20.

[0013] The beneficial effects of the above technical solutions include: the upper limit of the aspect ratio of the polymer particles is within a certain standard, which can effectively improve the fracture strength and compaction density of the solid-state electrolyte film, so that the electrical conductivity of the solid-state electrolyte film and the cycle number of the battery are higher.

[0014] 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.

[0015] The beneficial effects of the above technical solutions include: the above specific types of polymer particles have specific compaction density requirements and fracture strength requirements under certain pressure conditions, and also have advantages such as abundant sources.

[0016] In some exemplary embodiments, the polymer particles contain polar functional groups selected from one or more of hydroxyl groups, carboxyl groups, and cyano groups.

[0017] The beneficial effects of the above technical solutions include that the polar groups present in the polymer help to form chemical bonds and actions with the PS groups (phosphorus-sulfur groups) in the sulfide electrolyte material, so that a well-chemically-compatible interface can be formed between the polymer particles and the sulfide electrolyte material, which is conducive to improving the two-phase dispersibility and structural stability in the composite brick wall structure, improving the ionic conductivity and fracture strength of the solid-state electrolyte, and further improving the capacity performance and cycle life of the battery.

[0018] In some exemplary embodiments, the polymer particles are polysaccharide polymers, which can be one or more of xanthan gum, guar gum, gum arabic, starch, cellulose, glycogen, chitin, agar and inulin.

[0019] The beneficial effects of the above technical solutions include that the polysaccharide polymers have very excellent mechanical properties, not only have high fracture strength, but also can form a high-density structure under pressure conditions, and have good mechanical matching with the sulfide electrolyte; and a large number of polar functional groups such as hydroxyl groups exist on the molecular chain of the polysaccharide polymers, which can form a well-chemically-compatible and stable interface with the sulfide electrolyte. At the same time, the polysaccharide polymers also have the advantages of abundant source and low cost, which can further reduce the cost of the solid-state electrolyte and have excellent application prospects.

[0020] In some exemplary embodiments, the polymer particles have a polymerization degree of 1 million to 5 million, which can be 20 million to 200 million.

[0021] The beneficial effects of the above technical solutions include that the polymer particles with a specific polymerization degree are selected, so that the polymer particles have appropriate mechanical strength, which can effectively improve the fracture strength of the overall solid-state electrolyte film, and at the same time, is conducive to forming a uniform and dense composite solid-state electrolyte film, so that the ionic conductivity of the solid-state electrolyte film and the capacity performance, cycle number and energy density of the battery are effectively improved.

[0022] In some exemplary embodiments, the sulfide electrolyte material is selected from one or more of Li3PS4, Li7P3S 11 , Li6PS5Cl and Li 10 GeP2S 12 .

[0023] The beneficial effects of the above technical solutions include that the specific type of sulfide electrolyte material can better meet the performance requirements, so that the ionic conductivity of the solid-state electrolyte film is better, and the battery has better capacity performance, cycle number and energy density.

[0024] 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 the polymer particles, the mass of the binder is 0.5 to 20 parts by mass, optionally 1 to 10 parts by mass, and more optionally 2 to 5 parts by mass.

[0025] The beneficial effects of the above technical solution include: the addition of a binder can improve the overall mechanical properties of the solid electrolyte membrane, helping to ensure the ultra-thin solid electrolyte membrane's ability to resist battery electrode deformation, thereby extending the cycle performance of the solid-state battery. The appropriate amount of binder added facilitates the formation of an ultra-thin solid electrolyte membrane with a thickness of less than 50μm, while ensuring that the solid electrolyte membrane has good electrical conductivity.

[0026] In some exemplary embodiments, the solid electrolyte membrane has a thickness of 20-200 μm.

[0027] The beneficial effects of the above technical solution include: the solid electrolyte membrane has a suitable thickness, and the battery can have both good cycle times and energy density.

[0028] In a second aspect, the present application provides a solid-state battery, which includes the solid-state electrolyte membrane provided in the first aspect.

[0029] In a third aspect, the present application provides a device equipped with a solid-state battery as provided in the second aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0031] Figure 1 Schematic diagram of the organizational structure of the solid electrolyte membrane with a composite brick wall structure provided in an embodiment of the present application. DETAILED DESCRIPTION

[0032] To make the purpose, technical solutions and advantages of the examples of the present application clearer, the technical solutions in the examples of the present application will be described clearly and completely below. Where specific conditions are not specified in the examples, conventional conditions or conditions recommended by the manufacturer are used. Where the manufacturer of the reagents or instruments is not specified, they are all conventional products that can be purchased commercially.

[0033] It should be noted that “and / or” in this application, such as “Feature 1 and / or Feature 2”, refers to three situations: “Feature 1” alone, “Feature 2” alone, or “Feature 1” plus “Feature 2”.

[0034] In addition, in the description of this application, unless otherwise specified, the meaning of "multiple" in "one or more" refers to two or more; the range of "value a ~ value b" includes the two end values ​​"a" and "b", and the "unit of measurement" in "value a ~ value b + unit of measurement" represents the "unit of measurement" of both "value a" and "value b"; descriptions such as "above value c" and "within value c" all refer to the number including value c itself.

[0035] The solid electrolyte membrane, solid-state battery and device of the embodiments of the present application are described in detail below.

[0036] In the first aspect, the present application provides a solid electrolyte membrane. The solid electrolyte membrane includes a sulfide electrolyte material and polymer particles, and the polymer particles are dispersed in the sulfide electrolyte material. Based on the total mass of the sulfide electrolyte material and the polymer particles as 100 parts by mass, the mass of the polymer particles is 1 to 50 parts by weight. Among them, more than 90wt% of the polymer particles (particles with a mass fraction of more than 90% of the polymer particles) have a size of 1 to 500μm; after the polymer particles are pressed and formed under 100 to 500MPa, they have a compaction density greater than 95% and a fracture strength greater than 50MPa.

[0037] In the solid electrolyte membrane of the present application, polymer particles with a size mainly of 1 to 500 μm are easier to disperse evenly; moreover, the size of the polymer particles is well matched with the average particle size of the sulfide electrolyte material (5 to 20 μm), so that the solid electrolyte membrane can maintain a good compaction density, thereby effectively maintaining the interface contact and ion transmission channel between the sulfide electrolyte material and the polymer particles, which is conducive to maintaining the electrochemical properties such as good conductivity and high fracture strength of the solid electrolyte membrane. At the same time, the solid-state battery can better combine a larger capacity, a higher energy density and a larger number of cycles. If the size distribution range of the polymer particles is too large and it is not possible to meet the requirement that more than 90wt% of the polymer particles are 1 to 500 μm, the polymer particles will be difficult to disperse evenly and have poor matching with the average particle size of the sulfide electrolyte material, which will lead to the overall performance of the battery attenuation. It should be noted that in the embodiments of the present application, the size range of the polymer particles that meet the specific conditions, its lower limit refers to the minimum size among all polymer particles that meet the specific conditions, and its upper limit refers to the maximum size among all polymer particles that meet the specific conditions.

[0038] Since a large portion of the particles can be controlled within the proper size range by sieving through double screens, for example, 95wt% of the particles can be well controlled within the target size range. As an example, the size of 95wt% or more of the polymer particles is 1-500μm, so that more polymer particles are distributed in the range of 1-500μm.

[0039] The better the match between the size of the polymer particles and the average particle size of the sulfide electrolyte material, the higher the compaction density of the polymer particles and the sulfide electrolyte material, the better the interface contact between the sulfide electrolyte material particles and the polymer particles and the ion transport channel can be maintained, while the growth of lithium dendrites along the internal pores of the electrolyte is inhibited, so that the fracture strength of the solid-state electrolyte film and the cycle number of the battery are higher. In the embodiments of the present application, the size of the polymer particles is optionally concentrated towards 5-20μm.

[0040] In some optional embodiments, in the case where the size of 90wt% or more of the polymer particles is 1-500μm, optionally, the size of 35wt% or more of the polymer particles is 5-20μm.

[0041] Further, the size of 99wt% or more of the polymer particles is 1-500μm; optionally, the size of 40wt% or more of the polymer particles is 5-20μm.

[0042] Further, the size of 99wt% or more of the polymer particles is 2-100μm; optionally, the size of 55wt% or more of the polymer particles is 5-20μm.

[0043] As an example, the size of 99wt% or more of the polymer particles is 5-20μm.

[0044] In some exemplary embodiments, the size of the 99wt% or more of the polymer particles is, for example but not limited to, in the range between any two of 1μm, 2μm, 5μm, 10μm, 20μm, 50μm, 100μm, 200μm and 500μm.

[0045] As an example, the polymer particles of the target size can be obtained by sieving, for example, to obtain polymer particles of which 99wt% or more have a size of 1-500 pm, the polymer particles can be sieved through a 32-mesh sieve to obtain undersize, and then the undersize is sieved through a 10,000-mesh sieve to obtain oversize, and the oversize is the target particles; to obtain polymer particles of which 99wt% or more have a size of 2-100 pm, the polymer particles can be sieved through a 150-mesh sieve to obtain undersize, and then the undersize is sieved through a 5,000-mesh sieve to obtain oversize, and the oversize is the target particles; to obtain polymer particles of which 99wt% or more have a size of 5-20 pm, the polymer particles can be sieved through a 600-mesh sieve to obtain undersize, and then the undersize is sieved through a 2,000-mesh sieve to obtain oversize, and the oversize is the target particles.

[0046] It is considered that when the content of the polymer particles is too low, the polymer particles can only be sporadically dispersed in part of the solid-state electrolyte film, and the fracture strength of the whole solid-state electrolyte film is limited. Therefore, controlling the lower limit of the amount of polymer particles to a certain standard can effectively improve the fracture strength of the whole solid-state electrolyte film, improve the anti-cracking ability of the solid-state electrolyte film, and thus effectively improve the maximum cycle number of the battery.

[0047] At the same time, it is considered that the polymer particles themselves cannot conduct lithium ions, and when the content of the polymer particles is too high, it will also have a great impact on the ion transmission ability inside the solid-state electrolyte film, which will significantly reduce the conductivity of the solid-state electrolyte film and the capacity and energy density of the battery. Therefore, controlling the upper limit of the amount of polymer particles within a certain standard can better meet the performance requirements of the conductivity of the solid-state electrolyte film and the capacity and energy density of the battery.

[0048] In some exemplary embodiments, 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 mass, further optionally 5-50 parts by mass, or 5-35 parts by mass, or 10-35 parts by mass, or 10-20 parts by mass, for example but not limited to any one of 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, or a range between any two of them.

[0049] At the same time, the amount of the sulfide electrolyte material will affect the conductivity of the solid-state electrolyte film and the battery capacity. Based on 100 parts by mass of the total mass of the sulfide electrolyte material and the polymer particles, the mass of the sulfide electrolyte material is not less than 50 parts by mass, which ensures that the material has a suitable conductivity and battery capacity.

[0050] In the embodiments of the present application, the 100-500 MPa pressing forming condition is close to the forming pressure of the solid-state electrolyte film; as an example, the pressure of the pressing forming can be selected as 200-400 MPa, for example, 300 MPa. The selection of the compaction density of the polymer particles under a certain pressing forming condition is to consider that the densification needs to be achieved by applying external pressure when preparing the solid-state electrolyte film, and the polymer particles that can be densification formed under a certain pressure condition can be compatible with the preparation process of the sulfide electrolyte material, reduce the manufacturing cost of the solid-state electrolyte film of the composite system; it can also improve the densification degree of the solid-state electrolyte film of the composite system, reduce the pores generated in the process, improve the ionic conductivity of the solid-state electrolyte film, and at the same time inhibit the growth of lithium dendrites along the internal pores, thereby improving the composite effect of the sulfide electrolyte material and the polymer particles. The selection of the breaking strength of the polymer particles under a certain pressing forming condition is to consider that when the polymer particles themselves have a certain mechanical strength, the stable geometric shape of the polymer particles can be effectively maintained. When the mechanical strength of the polymer particles is too low, it is easy to produce deformation defects under local stress, it is difficult to effectively inhibit the crack propagation, and it is difficult to well play the function of the composite brick wall structure to inhibit the penetrating defects.

[0051] In the present application, by adding polymer particles into the sulfide electrolyte material, a composite brick wall structure is obtained in which the polymer particles are dispersed in the sulfide electrolyte material. As shown in the composite brick wall structure, Figure 1 the sulfide electrolyte material constitutes a wall structure, and the polymer particles constitute a brick structure. In the composite system, polymer particles with a certain particle size are used, and the compaction density and breaking strength of the polymer particles under a certain pressing forming condition are regulated, and under the joint action of the specific polymer particles and the sulfide electrolyte material: on the one hand, the polymer particles can also effectively improve the toughness of the solid-state electrolyte film, so that the solid-state electrolyte film is difficult to crack; on the other hand, the cracks generated by the stress of the sulfide electrolyte material in the solid-state electrolyte film will also be blocked by the polymer particles when expanding, thereby effectively avoiding the formation of defects penetrating the solid-state electrolyte film.

[0052] In the embodiments of the present application, the particle size, amount, compaction density and breaking strength of the polymer particles are controlled according to specific conditions, so that the solid-state electrolyte film has a high compaction density and breaking strength, thereby effectively inhibiting the phenomenon that the lithium dendrites grow to pierce the solid-state electrolyte film, and reducing the risk of short circuit in the battery.

[0053] In some alternative embodiments, the solid-state electrolyte film is compression molded under a pressure of 100-500 MPa, optionally under a pressure of 200-400 MPa, for example under a pressure of 300 MPa. The solid-state electrolyte film has a compaction density greater than 79%, or greater than 84%, or greater than 90%, or greater than 95%; and the solid-state electrolyte film has a fracture strength 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.

[0054] It should be noted that in the description of the present application, the first material is dispersed in the second material, which means that the second material is used as the medium for the discrete distribution of the first material, so that the first material is in a discrete distribution state in the second material.

[0055] It is considered that the morphology of the polymer particles will affect the dispersion of the polymer particles in the solid-state electrolyte film, and will also affect the mechanical properties of the polymer particles themselves, and will also affect the interface contact between the polymer particles and the sulfide electrolyte material. Therefore, selecting polymer particles with specific morphology requirements is beneficial to improve the compaction density and fracture strength of the solid-state electrolyte film.

[0056] It is found that among the morphology characteristics of the polymer particles, the aspect ratio of the polymer particles has a significant influence on the compaction density and fracture strength of the solid-state electrolyte film. The polymer particles need to reach micron-level size to maintain sufficient mechanical strength and effectively inhibit the penetration of lithium dendrites and the expansion of cracks. When the aspect ratio of the polymer particles is too large, part of the particles will be too small (nanometer level), which will not effectively inhibit the expansion of cracks and improve the fracture strength of the solid-state electrolyte film, and is not conducive to improving the cycle number of the battery. Moreover, the polymer particles with a large aspect ratio are more likely to form a local winding structure, resulting in the residual of part of the pores, which is not conducive to improving the compaction density of the solid-state electrolyte film during the compression molding process, resulting in a decrease in the conductivity of the solid-state electrolyte film.

[0057] In some exemplary embodiments, the aspect ratio of the polymer particles should be controlled within 50, optionally within 25, and more optionally within 20. For example, but not limited to, the aspect ratio of the polymer particles is 20, 15, 10 or 5. A large aspect ratio will reduce the overall mechanical strength of the solid-state electrolyte film, and ultimately reduce the cycle performance of the battery.

[0058] In order to better meet the compaction density and fracture strength requirements of the polymer particles under a certain pressure condition, 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.

[0059] The research also found that the polar groups present in the polymer help form chemical bonds and interactions with the PS groups in the sulfide electrolyte material, allowing the polymer particles and the sulfide electrolyte material to form an interface with good chemical compatibility, which is conducive 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-state electrolyte, and further improving the capacity performance and cycle life of the battery.

[0060] Exemplarily, the polymer particles contain polar functional groups selected from one or more of a hydroxyl group, a carboxyl group, and a cyano group.

[0061] As an example, the polymer particles are polysaccharide polymers, which can further be selected from one or more of xanthan gum, guar gum, gum arabic, starch, cellulose, glycogen, chitin, agar, and inulin. The polysaccharide polymers have excellent mechanical properties, not only having high fracture strength, but also being able to form a high-density structure under pressure conditions, and having good mechanical matching with the sulfide electrolyte; and there are a large number of polar functional groups such as hydroxyl groups on the molecular chains of the polysaccharide polymers, which can form an interface with good chemical compatibility and stability with the sulfide electrolyte. At the same time, the polysaccharide polymers have the advantages of abundant sources and low cost, which can further reduce the cost of the solid-state electrolyte and have excellent application prospects.

[0062] Considering that the degree of polymerization of the polymer particles affects the mechanical properties of the polymer particles, the polymer particles need to have a suitable degree of polymerization. When the degree of polymerization of the polymer particles is too low, the polymer molecular chains are short and soft, which makes the mechanical strength of the polymer particles low, and the improvement of the fracture strength of the overall solid-state electrolyte film is limited, and it is difficult to effectively inhibit the growth of lithium dendrites and the expansion of internal crack defects of the electrolyte. When the degree of polymerization of the polymer particles is too high, the mechanical strength is high, and the research also found that when the mechanical strength of the polymer particles is too high, the mechanical property matching between the polymer particles and the sulfide electrolyte material is poor, which causes the polymer particles and the sulfide electrolyte material to easily form point-to-point contact, and it is difficult to form good physical contact between the two-phase interface of the sulfide electrolyte material and the polymer particles.

[0063] In some exemplary embodiments, the degree of polymerization of the polymer particles is 1-5 million, or 2-2 million, or 4-1 million, such as but not limited to any one of 1 million, 2 million, 4 million, 7 million, 10 million, 20 million, and 50 million or a range between any two of them.

[0064] 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-state electrolyte film, and it will also cause the overall mechanical strength of the composite solid-state electrolyte film to be poor; on the other hand, it is easy to cause the polarization of the two-phase interface to increase, which causes the conductivity of the solid-state electrolyte film and the capacity performance, cycle number and energy density of the battery to all decrease.

[0065] It can be understood that in the raw material for preparing the solid-state electrolyte film of the present application, the sulfide electrolyte material can be selected from the material types known in the art. Considering the conductivity of the solid-state electrolyte film, and the capacity performance, cycle number and energy density of the battery, etc., which will be different due to the differences in the properties of the sulfide electrolyte material, the sulfide electrolyte material is optionally selected from one or more of Li3PS4, Li7P3S 11 , Li6PS5Cl and Li 10 GeP2S 12 .

[0066] It can be understood that in the solid-state electrolyte film of the present application, the solid-state electrolyte film can be composed of the above-mentioned sulfide electrolyte material and polymer particles, and the raw material of the solid-state electrolyte film can also include an additive.

[0067] It has been found that due to the many hard contacts between the above-mentioned specific sulfide electrolyte material and polymer particles, it is difficult for the solid-state electrolyte film to undergo large deformation under the action of preparation pressure. When the battery electrode swells seriously, stress residues or stress unevenness problems will occur locally, which causes the solid-state electrolyte film with a composite brick wall structure to have the risk of structural damage. Considering that reducing the thickness of the solid-state electrolyte film is beneficial to improving the energy density of the battery, however, it has been found that when the thickness of the solid-state electrolyte film is reduced to a certain thickness, the cycle performance of the battery will deteriorate, therefore, in order to meet the needs of energy density and cycle performance, the solid-state electrolyte film needs to have a suitable thickness.

[0068] In some exemplary embodiments, the thickness of the solid-state electrolyte film is 20-200 μm, at which the battery can have better cycle number and energy density.

[0069] In the embodiment in which the solid-state electrolyte film is only composed of the above-mentioned sulfide electrolyte material and polymer particles, it has been further found that when the thickness of the solid-state electrolyte film is above 100 μm, the cycle number of the battery is significantly higher; and when the thickness of the solid-state electrolyte film is below 100 μm, especially below 50 μm, the energy density of the battery is significantly higher.

[0070] The research further found that adding a binder to the solid-state electrolyte film can improve the deformation ability of the solid-state electrolyte film under the action of preparation pressure, and thus better alleviate the local stress caused by the volume expansion of the electrode, and maintain the structural stability of the solid-state electrolyte film. Therefore, the addition of the binder can improve the overall mechanical properties of the solid-state electrolyte film, which is conducive to ensuring the ability of the ultra-thin solid-state electrolyte film with a thickness of less than 50 μm to resist the deformation of the battery electrode, and thus prolonging the cycle performance of the solid-state battery.

[0071] In some exemplary embodiments, the solid-state electrolyte film further comprises a binder, which is dispersed in the solid-state electrolyte film in the form of filaments.

[0072] Considering the low ion conduction ability of the binder and the influence of the binder on the film-forming performance of the solid-state electrolyte film, the binder needs to have a suitable amount of addition. When the amount of the binder is too small, it is difficult to form an ultra-thin solid-state electrolyte film; when the amount of the binder is too large, the excess binder will cause the surface of the sulfide electrolyte material to be coated with the binder, which will affect the lithium ion migration at the interface, and thus will cause the electrical conductivity of the solid-state electrolyte film to decrease significantly, so that the solid-state electrolyte film cannot well meet the electrical conductivity requirement of the battery.

[0073] As an example, based on 100 parts by mass of the total mass of the sulfide electrolyte material and the polymer particles, the mass of the binder is 0.5-20 parts by mass, or 1-10 parts by mass, or 2-5 parts by mass, for example but not limited to any one 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, or a range between any two of them.

[0074] In the embodiment in which the solid-state electrolyte film further comprises the binder in the above-mentioned amount of addition, it is further found that when the thickness of the solid-state electrolyte film is more than 30 μm, the cycle number of the battery is significantly higher; and when the thickness of the solid-state electrolyte film is less than 100 μm, especially less than 50 μm, the energy density of the battery is significantly higher.

[0075] Exemplarily, the thickness of the solid-state electrolyte film is 30-50 μm, for example but not limited to any one of 30 μm, 35 μm, 40 μm, 45 μm, and 50 μm, or a range between any two of them, at this time the solid-state electrolyte film is in an ultra-thin state, and has more cycle numbers and higher energy density.

[0076] It can be understood that in the solid-state electrolyte film of the present application, the binder can be selected from the material types known in the art. Considering that the structure and morphology of the binder can affect the dispersion state of the materials inside the solid-state electrolyte film, and in turn affect the mechanical and electrochemical properties of the solid-state battery to a certain extent, the binder is optionally selected from one or more of polyethylene, polyethylene oxide, polyvinylidene fluoride, polypropylene, polyisobutylene, butadiene-styrene rubber, and butyl nitrile rubber.

[0077] In addition, the solid-state electrolyte film provided by the embodiments of the present application can be prepared by methods known in the art. As an example, in the embodiment in which the solid-state electrolyte film is composed of a sulfide electrolyte material and polymer particles, the solid-state electrolyte film is prepared by a dry process; in the embodiment in which the solid-state electrolyte film is composed of a sulfide electrolyte material, polymer particles, and a binder, the solid-state electrolyte film is prepared by a wet process.

[0078] In some exemplary embodiments, the dry process comprises: mixing the sulfide electrolyte material and the polymer particles to obtain a composite raw material powder; and pressing the composite raw material powder into a shape under a specific operating pressure. The operating pressure is optionally 100-500 MPa, or 200-400 MPa, for example 300 MPa.

[0079] In some exemplary embodiments, the wet process comprises: mixing the sulfide electrolyte material and the polymer particles to obtain an electrolyte powder; dissolving the 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 on a substrate to form a coating layer of a specific thickness, and then drying the coating layer by vacuum heat treatment.

[0080] In the wet process, the binder is dissolved in the organic solvent, and the sulfide electrolyte material and the polymer particles are insoluble in the organic solvent, so that the binder, the sulfide electrolyte material, and the polymer particles can effectively function respectively.

[0081] Optionally, the organic solvent is selected from one or more of toluene, xylene, trimethylbenzene, n-heptane, cyclohexane, ethyl acetate, and butyl butyrate.

[0082] As an example, the organic solvent is one or more of toluene, xylene, or trimethylbenzene, the binder is butadiene-styrene rubber and / or polyisobutylene, and the polymer particles are xanthan gum and / or guar gum.

[0083] 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 chitin.

[0084] In a second aspect, the present application provides a solid-state battery comprising the solid-state electrolyte film provided in the first aspect.

[0085] It can be understood that, in addition to the solid-state electrolyte film being different from the film known in the art, the rest of the materials and structure of the solid-state battery provided in the embodiments of the present application can refer to the configuration manner known in the art, and the preparation of the solid-state battery can also refer to the method known in the art.

[0086] As an example, the positive electrode material in the solid-state battery comprises a positive electrode active material, a conductive agent and a second binder. The positive electrode active material can 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, olivine structure lithium-containing phosphate, etc. Further, the positive electrode active material can be one or more of LiCoO2, LiNiO2, LiMnO2, LiMn2O4, Li6PS5Cl, 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 O2, LiFePO4(LFP), LiMnPO4. The conductive agent can be one or more of acetylene black, conductive carbon black, carbon fiber, carbon nanotube, ketjen black. The second binder can be one or more of polyvinylidene fluoride and polyvinylidene fluoride modified (e.g., carboxylic acid, acrylic acid, acrylonitrile, etc.) derivatives.

[0087] In some embodiments, the solid-state battery provided in the present application can be assembled into a battery module, and 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 demand of the battery module.

[0088] The battery module described above can also be assembled into a battery pack, and the number of battery modules contained in the battery pack can be adjusted according to the application scenario and capacity demand of the battery pack.

[0089] In a third aspect, the present application provides a device equipped with the solid-state battery provided in the second aspect, which provides power supply for the device.

[0090] In embodiments of the present application, the device can be, but is not limited to, a mobile communication terminal (such as a mobile phone, a notebook, a tablet, a POS machine, and a vehicle-mounted computer, etc.), an electric vehicle (such as a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, an electric bicycle, an electric scooter, an electric golf cart, an electric truck, etc.), an electric train, a ship, a satellite, and a power storage system, etc.

[0091] It can be understood that the device can select a solid-state battery, a battery module, or a battery pack according to the use requirement.

[0092] The features and performances of the present application are further described in detail below in combination with embodiments.

[0093] The solid-state batteries of each embodiment and comparative example are prepared and tested according to the following method.

[0094] I. Preparation of the solid-state battery

[0095] (1) Preparation of the solid-state electrolyte film

[0096] The example without binder adopts a dry process, and the example with binder adopts a wet process.

[0097] The dry process includes:

[0098] S11. Screen the polymer powder through a screen with a specific mesh number to obtain polymer particles with a specific size.

[0099] S12. Mix the polymer particles obtained in step S11 and the sulfide electrolyte material powder according to a specific mass ratio to realize dry pre-dispersion, and obtain a pre-dispersed powder.

[0100] S13. Homogeneously disperse the pre-dispersed powder obtained in step S12 by ball milling to obtain a composite raw material powder.

[0101] S14. Press the composite raw material powder obtained in step S13 at an operating pressure of 300 MPa to form a solid-state electrolyte film with a specific thickness.

[0102] The wet process includes:

[0103] S21. Screen the polymer through a screen with a specific mesh number to obtain polymer particles with a specific size.

[0104] S22. Mix the polymer particles obtained in step S21 and the sulfide electrolyte material powder according to a specific mass ratio to realize dry pre-dispersion, and obtain a pre-dispersed powder.

[0105] S23. Dissolve the binder of a certain mass fraction in an organic solvent to form a uniformly dispersed binder solution.

[0106] S24. Mix the pre-dispersed powder obtained in S22 and the binder solution obtained in S23 in proportion, and disperse by ball milling to form a uniform composite electrolyte slurry.

[0107] S25. Coating the composite electrolyte slurry in S24 on a substrate, controlling the thickness of the coated electrolyte slurry layer by changing the size of the doctor blade, and then drying the coated slurry by vacuum heat treatment to obtain a solid-state electrolyte film of a certain thickness.

[0108] (2) Preparation of positive electrode sheet

[0109] S31. Mix LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2, Li6PS5Cl electrolyte material, conductive agent Super-P, and butyl rubber binder in a mass ratio of 70:24:3:3 to obtain a mixture.

[0110] S32. Add the mixture obtained in S31 to a toluene solvent and stir under the action of a vacuum stirrer until the system is uniform to obtain a positive electrode slurry.

[0111] S33. Uniformly coat the positive electrode slurry obtained in S32 on both surfaces of the positive current collector aluminum foil, dry at room temperature, then transfer to an oven for further drying, and then cold-press and cut to obtain a positive electrode sheet.

[0112] (3) Preparation of negative electrode sheet

[0113] Attach a lithium foil to both surfaces of a negative current collector copper foil by rolling, and then cut to obtain a negative electrode sheet.

[0114] (4) Preparation of whole battery

[0115] Stack the positive electrode sheet, solid-state electrolyte film, and lithium metal negative electrode prepared by the above preparation method in sequence, and press at 300 MPa to prepare a full solid-state lithium metal battery.

[0116] II. Test of performance parameters

[0117] Test of raw materials:

[0118] (1) Test of polymer particle size: uniformly disperse the polymer particles on the surface of a conductive tape, and observe the polymer particle samples in more than three regions using a scanning electron microscope. Based on the particle size statistical results of no less than 50 polymer particles, the average size of the polymer particle samples is obtained.

[0119] Test on product:

[0120] (2) Conductivity test: The solid-state electrolyte film is pressed into a round sheet under a pressure of 300 MPa, and the ohmic impedance of the electrolyte sheet is measured using a Chenhua electrochemical workstation. In the test, the ambient temperature is 25°C, the frequency range is 1 Hz-1 MHz, and the perturbation signal is 5 mV. Based on the impedance, thickness, and area of the electrolyte sheet, the ionic conductivity is calculated.

[0121] (3) Compacted density test: The solid-state electrolyte film or polymer particles are pressed into a round sheet under a pressure of 300 MPa, and the compacted porosity w of the electrolyte sheet is measured using a true density instrument. The compacted density is 1-w.

[0122] (4) Fracture strength test: The material is pressed into a round sheet under a pressure of 300 MPa, and the stress change of the round sheet sample during the fracture process under the puncture of the probe pressure is measured using a tensile testing machine. Based on the fracture limit stress F, the sample thickness d, the sample diameter R, and the sample support frame spacing s, the corresponding fracture strength E is calculated.

[0123] (5) Maximum tensile strain test: The solid-state electrolyte film is pressed into a strip-shaped sample under a pressure of 300 MPa, and the deformation of the strip-shaped sample when subjected to tensile stress on both sides is measured using a tensile testing machine. The ratio of the deformation x of the sample when it is pulled apart to the initial length L of the sample is the maximum tensile strain, i.e., x / L.

[0124] (6) Capacity delivery test: The capacity performance of the solid-state battery is measured using a blue electric tester. In the test, the working temperature is 25°C, the charge and discharge rate is 0.1C, and the cutoff voltage is 2.8-4.2V.

[0125] (7) Cycle performance test: The charge and discharge cycle capacity of the solid-state battery is measured using a blue electric tester. In the test, the working temperature is 25°C, the charge and discharge rate is 0.1C, and the cutoff voltage is 2.8-4.2V. The number of cycles when the battery short-circuits or the cycle capacity is lower than 50% of the first cycle capacity is taken as the maximum cycle number of the battery.

[0126] (8) Energy density test: The energy released by the solid-state battery during the first charge and discharge process is measured and recorded using a blue electric tester, and then the energy is divided by the weight of the battery to obtain the energy density, which is expressed in Wh / kg. In the test, the working temperature is 25°C, the charge and discharge rate is 0.1C, and the cutoff voltage is 2.8-4.2V.

[0127] The composition of the solid-state electrolyte film of the solid-state battery is shown in Table 1, wherein the mass of the sulfide electrolyte material, the mass of the polymer, and the mass of the binder are all converted from the total mass of 100 parts by mass of the sulfide electrolyte material and the polymer particles, and are hereinafter referred to as converted parts by mass; the performance test results of the solid-state battery are shown in Table 2, and are as follows:

[0128] Table 1.1 Composition of the solid-state electrolyte film in each of the examples and the comparative example

[0129]

[0130]

[0131]

[0132]

[0133] Table 2.1 Performance test results of the solid-state battery in each of the examples and the comparative example

[0134]

[0135]

[0136] The difference between Examples 1-4 and Comparative Example 1 is only the size distribution of the polymer particles. Examples 1-4 meet the requirement that 90 wt% or more of the polymer particles have a size of 1-500 μm, while Comparative Example 1 does not meet the requirement that 90 wt% or more of the polymer particles have a size of 1-500 μm (20 wt% of the polymer particles have a size outside the range of 1-500 μm). Through comparison of Examples 1-4 and Comparative Example 1, it can be seen that the solid-state electrolyte film of Examples 1-4 has higher conductivity and breaking strength, and the cycle number of the battery is significantly improved. Through comparison of Examples 1-4, it can be seen that when the polymer particles are concentrated to 5-20 μm, the conductivity and breaking strength of the solid-state electrolyte film and the cycle number of the battery can be further improved. In particular, when 99 wt% or more of the polymer particles have a size of 5-20 μm in Example 4, the conductivity and breaking strength of the solid-state electrolyte film and the cycle number of the battery are all significantly improved.

[0137] The difference between Examples 4-9 and Comparative Examples 2-3 is only in the content of the polymer particles. It can be known from the comparison between Examples 4-9 and Comparative Examples 2-3 that the content of the polymer particles has a significant influence on the conductivity of the electrolyte membrane and the capacity release, cycle number and energy density of the battery. In Examples 4-9, the content of the polymer particles is 1-50 parts by mass, and the conductivity of the electrolyte membrane and the capacity release, cycle number and energy density of the battery are all higher. In Comparative Example 2, the content of the polymer particles is less than 1 part by mass, and the breaking strength of the solid electrolyte membrane and the cycle number of the battery are both lower. In Comparative Example 3, the content of the polymer particles is higher than 50 parts by mass, and the conductivity and energy density of the solid electrolyte membrane are both lower. It can be known from the comparison between Examples 4-9 that when the content of the polymer particles increases from 1 part to 20 parts, the cycle number of the battery is significantly improved while maintaining a high solid electrolyte membrane conductivity and battery capacity release. Among them, when the content of the polymer particles is more than 5 parts by mass, especially more than 10 parts by mass, the cycle number of the battery is ensured to be better. When the content of the polymer particles decreases from 50 parts to 35 parts, the conductivity of the electrolyte membrane and the capacity release of the battery are significantly improved while maintaining a high cycle number of the battery. When the content of the polymer particles decreases from 35 parts to 20 parts, the conductivity of the solid electrolyte membrane and the capacity release of the battery are significantly improved, and the cycle number of the battery is also significantly improved.

[0138] The difference between Example 4 and Examples 10-16 is only in the polymerization degree of the polymer particles. It can be known from the comparison between Example 4 and Examples 10-16 that the polymerization degree of the polymer particles has a significant influence on the compaction density and breaking strength of the polymer particles after compaction, and thus has a significant influence on the conductivity and breaking strength of the solid electrolyte membrane and the capacity release, cycle number and energy density of the battery. In Example 10, the polymerization degree of the polymer particles is less than 100,000, the breaking strength of the polymer particles after compaction is lower, and the breaking strength of the solid electrolyte membrane and the cycle number of the battery are significantly reduced. In Example 16, the polymerization degree of the polymer particles is higher than 5,000,000, the breaking strength of the polymer particles after compaction is lower, and the conductivity and breaking strength of the solid electrolyte membrane and the capacity release, cycle number and energy density of the battery are all significantly reduced.

[0139] The difference between Example 4 and Examples 17-19 is only in the type of sulfide electrolyte material. It can be known from the comparison between Example 4 and Examples 17-19 that when the sulfide electrolyte material is Li6PS5Cl, Li3PS4, Li7P3S 11 and Li 10 GeP2S 12 in the examples of the present application, the battery exhibits better performance in capacity release, cycle number and energy density.

[0140] The difference between Example 4, Examples 20 to 27 and Comparative Examples 4 to 7 is only the kind of material of the polymer particles. In Comparative Examples 4 to 5, the breaking strength of the polymer particles after compression molding does not satisfy the condition of being higher than 50 MPa. From the comparison between Example 4 and Comparative Examples 4 to 5, it can be seen that the electrical conductivity and the breaking strength of the solid electrolyte membrane in Example 4 are significantly improved, which makes the capacity performance and the energy density of the battery higher, and makes the cycle number of the battery significantly increased. In Comparative Examples 6 to 7, the compaction density of the polymer particles after compression molding does not satisfy the condition of being greater than 95%. The electrical conductivity and the breaking strength of the solid electrolyte membrane in Example 4 are significantly improved, which makes the capacity performance, the cycle number and the energy density of the battery significantly increased. From the comparison between Example 4 and Examples 20 to 27, it can be seen that when the polymer particles are polysaccharide polymer, polyhydrocarbon polymer, rubber polymer, polyamide polymer and polyester polymer, the battery shows better performance in the capacity performance, the cycle number and the energy density. Among them, when the polymer particles contain polar functional groups, the capacity performance and the cycle life of the battery can be better improved compared with those without polar functional groups; especially when the polymer is sugar polymer, the solid electrolyte membrane has better electrical conductivity and breaking strength, which makes the performance of the battery in the capacity performance, the cycle number and the energy density obviously better.

[0141] The difference between Example 4 and Examples 28 to 31 is only the thickness of the solid electrolyte membrane. From the comparison between Example 4 and Examples 28 to 31, it can be seen that in the case where the solid electrolyte membrane is only composed of sulfide electrolyte material and polymer particles, when the thickness of the solid electrolyte membrane is more than 100 μm, the cycle number of the battery is obviously higher; and 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 obviously higher.

[0142] The difference between Example 4 and Examples 32 to 36 is only the aspect ratio of the polymer particles. From the comparison between Example 4 and Examples 32 to 36, it can be seen that in the case where the solid electrolyte membrane is only composed of sulfide electrolyte material and polymer particles, in Examples 4 and 32 to 35, the aspect ratio of the polymer particles is controlled to be within 50, further within 25, especially within 20, the battery shows better capacity performance, cycle number and energy density; in Example 36, the aspect ratio of the polymer particles exceeds 50, the cycle number of the battery is obviously reduced.

[0143] The difference between Example 4 and Comparative Example 8 is only whether the polymer particles are contained in the solid electrolyte membrane. The difference between Example 29 and Comparative Example 9 is only whether the polymer particles are contained in the solid electrolyte membrane. The difference between Example 17 and Comparative Example 10 is only whether the polymer particles are contained in the solid electrolyte membrane. The difference between Example 18 and Comparative Example 11 is only whether the polymer particles are contained in the solid electrolyte membrane. The difference between Example 19 and Comparative Example 12 is only whether the polymer particles are contained in the solid electrolyte membrane. From the comparison between Example 4 and Comparative Example 8 and the comparison between Example 29 and Comparative Example 9, it can be seen that when the solid electrolyte membrane with different thickness specifications is used, and only the sulfide electrolyte material is used as the raw material of the solid electrolyte membrane, although the battery can obtain good capacity development and energy density, the cycle performance of the battery is significantly reduced. From the comparison between Example 4 and Comparative Example 8, the comparison between Example 17 and Comparative Example 10, the comparison between Example 18 and Comparative Example 11, and the comparison between Example 19 and Comparative Example 12, it can be seen that when the solid electrolyte membrane uses different sulfide electrolyte materials, and only the sulfide electrolyte material is used as the raw material of the solid electrolyte membrane, although the battery can obtain good capacity development and energy density, the cycle performance of the battery is significantly reduced.

[0144] Table 1.2 Composition of the solid electrolyte membrane in each example and comparative example

[0145]

[0146]

[0147]

[0148] Table 2.2 Test results of the related performance of the solid-state battery in each example and comparative example

[0149]

[0150]

[0151] The difference between Example 29 and Examples 37-44 is only that the solid electrolyte membrane of Examples 37-44 further comprises a binder, and the amount of the binder is different among Examples 37-44. By comparing Example 29 with Examples 37-44, it is known that the proper addition of the binder in the solid electrolyte membrane is beneficial to improve the cycle number of the battery. By comparing among Examples 37-44, it is known that when the equivalent mass fraction of the binder is less than 0.5 parts, the cycle number of the battery is low; when the equivalent mass fraction of the binder exceeds 20 parts, the conductivity of the solid electrolyte membrane is extremely low, and the capacity development, cycle number and energy density of the battery are all low. When the equivalent mass fraction of the binder is more than 1 part, especially more than 2 parts, the cycle number of the battery is high; when the equivalent mass fraction of the binder is less than 10 parts, especially less than 5 parts, the solid electrolyte membrane has a good conductivity, and the battery has a high energy development.

[0152] The difference between Example 41 and Examples 50-52 is only that the thickness of the solid electrolyte membrane is different. By comparing Example 41 with Examples 50-52, it is known that when the solid electrolyte membrane further comprises a binder, the cycle number of the battery is obviously higher when the thickness of the solid electrolyte membrane is more than 30 μm; and the energy density of the battery is obviously higher when the thickness of the solid electrolyte membrane is less than 100 μm, especially less than 50 μm, but the cycle number of the battery is too low when the thickness of the solid electrolyte membrane is less than 20 μm. When the thickness of the solid electrolyte membrane is 20-200 μm, especially when the thickness of the solid electrolyte membrane is 30-50 μm, the battery can have good cycle number and energy density.

[0153] The difference between Example 41 and Examples 53-57 is only that the aspect ratio of the polymer particles is different. By comparing Example 41 with Examples 53-57, it is known that when the solid electrolyte membrane further comprises a binder, in Examples 49 and 53-56, the aspect ratio of the polymer particles is controlled to be within 50, further within 25, especially within 20, and the battery shows good capacity development, cycle number and energy density; in Example 57, the aspect ratio of the polymer particles exceeds 50, and the cycle number of the battery is obviously reduced.

[0154] The difference between Example 41 and Comparative Example 13 is only whether the polymer particles are contained in the solid electrolyte membrane. The difference between Example 49 and Comparative Example 14 is only whether the polymer particles are contained in the solid electrolyte membrane. The difference between Comparative Example 13 and Comparative Example 15 is only the content of the binder in the solid electrolyte membrane, and the difference between Comparative Example 14 and Comparative Example 16 is only the content of the binder in the solid electrolyte membrane. From the comparison between Example 41 and Comparative Example 13 and the comparison between Example 49 and Comparative Example 14, it can be seen that, when the solid electrolyte membranes with different thickness specifications are used without adding polymer particles, although the addition of the binder in the solid electrolyte membrane can improve the maximum tensile strain of the solid electrolyte membrane, the breaking strength of the solid electrolyte membrane and the cycle number performance of the battery are significantly reduced. From the comparison between Comparative Example 13 and Comparative Example 15 and the comparison between Comparative Example 14 and Comparative Example 16, it can be seen that, when the amount of the binder in the solid electrolyte membrane is increased without adding polymer particles, although the addition of the binder in the solid electrolyte membrane can improve the maximum tensile strain of the solid electrolyte membrane, the breaking strength of the solid electrolyte membrane and the cycle number performance of the battery cannot be significantly improved.

[0155] The above-described examples are part of, but not all of the examples of the present application. The detailed description of the examples of the present application is not intended to limit the scope of the claimed present application, but merely represents selected examples of the present application. Based on the examples in the present application, all other examples obtained by a person of ordinary skill in the art without creative work shall fall within the scope of protection of the present application.

Claims

1. A solid electrolyte membrane, characterized in that The solid electrolyte membrane comprises a sulfide electrolyte material and polymer particles, wherein the polymer particles are dispersed in the sulfide electrolyte material, and the polymer particles are discretely distributed 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 to 50 parts by mass; More than 90 wt % of the polymer particles have a size of 1 to 500 μm, and more than 35 wt % of the polymer particles have a size of 5 to 20 μm; After being pressed and molded under a pressure of 100-500 MPa, the polymer particles have a compaction density greater than 95% and a fracture strength greater than 50 MPa; The polymer particles contain polar functional groups, which include one or more of hydroxyl, carboxyl and cyano groups; The solid electrolyte membrane further includes a binder; based on 100 parts by mass of the total mass of the sulfide electrolyte material and the polymer particles, the mass of the binder is 0.5 to 20 parts by mass.

2. The solid electrolyte membrane according to claim 1, characterized in that 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 have a size of 5 to 20 μm.

3. The solid electrolyte membrane according to claim 2, characterized in that More than 99 wt % of the polymer particles have a size of 5-20 μm.

4. The solid electrolyte membrane according to claim 1, wherein The aspect ratio of the polymer particles is within 50.

5. The solid electrolyte membrane according to claim 4, characterized in that The aspect ratio of the polymer particles is within 25.

6. The solid electrolyte membrane according to claim 4, characterized in that The aspect ratio of the polymer particles is within 20.

7. The solid electrolyte membrane according to claim 1, characterized in that The polymer particles are selected from one or more of polysaccharide polymers, polyhydrocarbon polymers, rubber polymers, polyamide polymers and polyester polymers.

8. The solid electrolyte membrane according to claim 1, characterized in that The polymer particles are polysaccharide polymers.

9. The solid electrolyte membrane according to claim 8, characterized in that The polysaccharide polymer is one or more of xanthan gum, guar gum, gum arabic, starch, cellulose, glycogen, chitin, agar and inulin.

10. The solid electrolyte membrane according to any one of claims 1 to 9, characterized in that The degree of polymerization of the polymer particles is 100,000 to 5,000,000.

11. The solid electrolyte membrane according to claim 10, characterized in that The degree of polymerization of the polymer particles is 200,000 to 2,000,000.

12. The solid electrolyte membrane according to claim 1, characterized in that The sulfide electrolyte material is selected from Li3PS4, Li7P3S 11 , Li6PS5Cl and Li 10 GeP2S 12 One or more of .

13. The solid electrolyte membrane according to claim 1, characterized in that The mass of the binder is 1 to 10 parts by mass.

14. The solid electrolyte membrane according to claim 1, characterized in that The mass of the binder is 2 to 5 parts by mass.

15. The solid electrolyte membrane according to claim 1, characterized in that The thickness of the solid electrolyte membrane is 20-200 μm.

16. A solid-state battery, characterized in that: The solid-state battery comprises the solid electrolyte membrane according to any one of claims 1 to 15.

17. A device, characterized in that Assembled with the solid-state battery as claimed in claim 16.

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