Membrane, electrode sheet, preparation method for electrode sheet, battery and electric device

Abstract

A membrane, comprising a sulfide solid electrolyte, an active material and a binder, wherein the elastic modulus ESE of the sulfide solid electrolyte is less than 30 GPa; the shear modulus GSE of the sulfide solid electrolyte is less than 12 GPa; and the sulfide solid electrolyte comprises Li and S, and further comprises at least one element selected from Sb, Sn, Te, Se, I and Br.

Description

Diaphragm, pole piece, pole piece preparation method, battery and electrical equipment

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the priority benefit of Chinese patent application No. 202410381194.8 filed on March 29, 2024, and incorporates the entirety of the application into this document. Technical Field

[0003] The present disclosure relates to the field of battery manufacturing technology, and more specifically, to a diaphragm, a pole piece, a method for preparing a pole piece, a battery, and an electrical device. Background Art

[0004] All-solid-state batteries replace the electrolytes of traditional batteries with solid-state electrolytes, and are considered the next generation of high-safety batteries due to their non-flammable properties. Sulfide solid electrolytes, among others, have attracted widespread attention in the industry due to their high ionic conductivity and low grain boundary resistance. However, sulfide solid electrolytes react chemically with highly polar solvents such as H2O and NMP (N-methylpyrrolidone), causing structural damage and loss of lithium conductivity. This poses challenges to the preparation of electrode slurries and wet coating methods for sulfide solid electrolyte systems.

[0005] Electrodes are typically prepared using a solvent-free process. Under high shear conditions, a binder forms a vast number of fibrous filaments, which intertwine with the solid electrolyte and active material to form a membrane. In dry-process membrane preparation using different particle sizes, varying shear tolerances lead to shear limits on binder fiberization, ultimately impacting membrane strength. Therefore, ensuring both the degree of binder fiberization and membrane strength under the same conditions is crucial. Summary of the Invention

[0006] One purpose of the present disclosure is to provide a new technical solution for a diaphragm, an electrode, a method for preparing an electrode, a battery, and an electrical device, which can at least solve the problems of poor diaphragm fiberization and strength in the prior art.

[0007] In a first aspect of the present disclosure, a membrane is provided, comprising a sulfide solid electrolyte, an active material and a binder, wherein the elastic modulus E of the sulfide solid electrolyte is SE <30GPa, the shear modulus G of the sulfide solid electrolyte SE <12 GPa, the sulfide solid electrolyte includes Li and S, and the sulfide solid electrolyte also includes at least one element of Sb, Sn, Te, Se, I, and Br.

[0008] Optionally, the elastic modulus E of the active materialAM >100 GPa, the shear modulus G of the active material AM >50GPa.

[0009] Optionally, the active material is a positive electrode active material.

[0010] Optionally, the elastic modulus E of the sulfide solid electrolyte SE <18GPa, the shear modulus G of the sulfide solid electrolyte SE <8GPa.

[0011] Optionally, the ratio of the elastic modulus of the sulfide solid electrolyte to the elastic modulus of the active material is 0.03<E SE / E AM <0.11, the ratio between the shear modulus of the sulfide solid electrolyte and the active material is 0.05 <G SE / G AM <0.12.

[0012] Optionally, the ionic conductivity of the sulfide solid electrolyte is greater than 0.1 mS / cm.

[0013] Optionally, the ratio of the mass of the non-metallic elements in the sulfide solid electrolyte to the total mass of the sulfide solid electrolyte is greater than 15%.

[0014] A second aspect of the present disclosure provides a pole piece, comprising the diaphragm described in the above embodiment, and further comprising a current collector, wherein the diaphragm is provided on at least one side of the current collector.

[0015] A third aspect of the present disclosure provides a method for preparing a pole piece, the method comprising:

[0016] The active material, the sulfide solid electrolyte, the binder and the conductive agent are mixed to form a mixed powder; wherein the elastic modulus E of the sulfide solid electrolyte is SE <30GPa, the shear modulus G of the sulfide solid electrolyte SE <12 GPa, the sulfide solid electrolyte includes Li and S, and the sulfide solid electrolyte further includes: at least one element of Sb, Sn, Te, Se, I, Br;

[0017] The mixed powder is subjected to a fiberizing treatment under the action of a shear force to obtain a treated powder;

[0018] The processed powder is subjected to hot rolling to prepare a membrane;

[0019] The film is composited on the current collector by hot pressing to prepare a pole piece.

[0020] Optionally, the elastic modulus E of the active material AM >100 GPa, the shear modulus G of the active material AM >50GPa.

[0021] Optionally, the binder is one or more of polytetrafluoroethylene, polyvinylidene fluoride, polyacrylic acid, polyacrylate, nitrile rubber, and styrene-butadiene rubber; and the conductive agent is one or more of acetylene black, carbon nanotubes, carbon fibers, and carbon black.

[0022] Optionally, the shear force is generated by ball milling, air milling, kneading, screw extrusion, high-speed dispersion, degassing or ultrasound.

[0023] Optionally, the hot rolling temperature is 120°C to 230°C.

[0024] A fourth aspect of the present disclosure provides a battery, comprising the pole piece described in the above embodiment, wherein the pole piece is manufactured using the pole piece manufacturing method described in the above embodiment.

[0025] A fifth aspect of the present disclosure provides an electrical device comprising the battery described in the above embodiment.

[0026] The membrane disclosed herein uses a soft sulfide solid electrolyte as the sulfide solid electrolyte, ensuring that the binder in the membrane containing the sulfide solid electrolyte and the active material can form a high degree of fiberization. The strength of the formed membrane after shearing is stronger and the material particles are more evenly distributed, thereby forming a membrane with excellent tensile strength and flexibility, effectively improving the strength and flexibility of the membrane, and facilitating the formation of a higher density membrane, thereby improving the performance of the membrane.

[0027] Other features and advantages of the present disclosure will become apparent from the following detailed description of exemplary embodiments of the present disclosure with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0029] FIG1 is a flow chart of a method for preparing a pole piece according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0030] Various exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. It should be noted that unless otherwise specifically stated, the relative arrangement of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present disclosure.

[0031] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the present disclosure, its application, or uses.

[0032] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered part of the specification.

[0033] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0034] It should be noted that like reference numerals and letters refer to like items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0035] Throughout the specification and claims of this disclosure, references to features using the terms "first" or "second" may explicitly or implicitly include one or more of these features. Throughout this disclosure, unless otherwise specified, "plurality" means two or more. Furthermore, the term "and / or" in the specification and claims refers to at least one of the connected entities, and the character " / " generally indicates an "or" relationship between the connected entities.

[0036] In the description of the present disclosure, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present disclosure and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present disclosure.

[0037] Throughout this disclosure, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood broadly. For example, these terms can refer to fixed, removable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediary; and internal communication between two components. Those skilled in the art will understand the specific meanings of these terms in this disclosure based on specific circumstances.

[0038] The diaphragm according to the embodiment of the present disclosure is described in detail below with reference to the accompanying drawings.

[0039] The membrane according to the embodiment of the present disclosure includes a sulfide solid electrolyte, an active material, and a binder. The elastic modulus E of the sulfide solid electrolyte is SE <30GPa, the shear modulus G of the sulfide solid electrolyte SE <12 GPa, the sulfide solid electrolyte includes Li and S, and the sulfide solid electrolyte also includes at least one element of Sb, Sn, Te, Se, I, and Br.

[0040] In other words, the membrane according to the embodiment of the present disclosure is mainly composed of a sulfide solid electrolyte and an active material, wherein the sulfide solid electrolyte adopts a soft solid electrolyte. In the dry film making process, after the binder powder and the solid electrolyte and the active material are mixed, under high shear conditions, the binder is formed into a huge number of fibrous filaments and intertwined with the electrolyte and the active material, and then a membrane is formed by rolling or the like. However, in the dry film making process for different particles (with different hardness and softness), the shear force required for the fiberization of the binder and the degree of fiberization after shearing will cause a large difference in the strength of the film. As far as the current sulfide solid electrolyte and active material system is concerned, dry film making has problems such as difficulty in film making and low film strength.

[0041] The sulfide solid electrolyte disclosed in the present invention can be a soft solid electrolyte, which can achieve sufficient fiberization of the binder, so that the prepared membrane has the characteristics of excellent tensile strength and good flexibility. Among them, the soft solid electrolyte here refers to the elastic modulus E SE <30GPa type, and shear modulus G SE Solid electrolytes with a tensile strength of less than 12GPa. During the binder fiberization stage of the soft sulfide solid electrolyte membrane preparation process, high shear forces cause the sulfide solid electrolyte particles to undergo a certain degree of refinement. The smaller particle size facilitates better filling of the gaps between the composite active materials during the later molding and compaction process. Combined with the soft sulfide solid electrolyte's low elastic modulus, high degree of fiberization of the electrode, and high flexibility, the result is a membrane with excellent tensile strength and flexibility, which facilitates the formation of a denser and more stable electrode structure, facilitates the conduction of lithium ions in the composite membrane, and improves the performance of the electrode and battery.

[0042] As an example, the elastic modulus E of a solid electrolyte SE It can be 29GPa, 25GPa, 20GPa, 15GPa, 10GPa, 5GP, etc. As an example, the shear modulus G of the solid electrolyte SE It can be 11 GPa, 10 GPa, 8 GPa, 6 GPa, 4 GPa, 2 GPa, etc.

[0043] According to one embodiment of the present disclosure, the elastic modulus E of the active material AM >100 GPa, the shear modulus G of the active material AM >50GPa. The active material disclosed herein can be a hard active material, which can ensure that the original state of the active material is maintained during the binder fiberization process, so that it is not damaged by shear force, thereby ensuring the stable performance of the active material. Among them, the hard active material here refers to the elastic modulus E AM >100GPa, shear modulus G AM Active material types >50GPa.

[0044] As an example, the elastic modulus E of the active material AM It can be 110 GPa, 150 GPa, 200 GPa, 250 GPa, 300 GPa, 350 GPa, 400 GPa, 450 GPa, 500 GPa, etc. As an example, the shear modulus G of the active material is AM It can be 51 GPa, 100 GPa, 150 GPa, 200 GPa, etc.

[0045] Therefore, according to the diaphragm of the embodiment of the present disclosure, the sulfide solid electrolyte adopts a soft solid electrolyte, and the active material adopts a hard active material, ensuring that the sulfide solid electrolyte and the active material can form a highly fiberized binder to wrap the sulfide solid electrolyte and material particles during the binder fiberization process. The strength of the formed diaphragm is stronger and the distribution of material particles is more uniform, thereby forming a diaphragm with excellent tensile strength and flexibility, effectively improving the strength and flexibility of the diaphragm, and facilitating the formation of a higher density diaphragm, thereby improving the performance of the diaphragm.

[0046] According to one embodiment of the present disclosure, the elastic modulus E of the sulfide solid electrolyte is SE <18GPa, shear modulus G of sulfide solid electrolyte SE <8GPa. In other words, the elastic modulus E of the sulfide solid electrolyte SE <18GPa, shear modulus G of sulfide solid electrolyte SE <8GPa. Optionally, the elastic modulus E of the sulfide solid electrolyte SE <18GPa, shear modulus G of sulfide solid electrolyte SE<7GPa. During the fiberization stage of sulfide-based solid electrolyte membrane preparation, high shear forces cause a certain degree of particle refinement. This smaller particle size facilitates better filling of the gaps between composite cathode particles during the subsequent molding and compaction process. Combined with the low elastic modulus, high degree of fiberization of the electrode sheet, and high flexibility, the sulfide solid electrolyte further facilitates the formation of a denser electrode structure, facilitating the conduction of lithium ions in the composite cathode, and improving electrode and battery performance.

[0047] According to one embodiment of the present disclosure, the ratio between the elastic modulus of the sulfide solid electrolyte and the active material is 0.03 < E SE / E AM <0.11, the ratio between the shear modulus of the sulfide solid electrolyte and the active material is 0.05<G SE / G AM <0.12. As an example, the ratio between the elastic modulus of the sulfide solid electrolyte and the active material is 0.04, 0.05, 0.07, 0.09, 0.1, etc. As an example, the ratio between the shear modulus of the sulfide solid electrolyte and the active material is 0.06, 0.07, 0.09, 0.1, 0.11, etc.

[0048] In other words, the ratio between the elastic modulus of the sulfide solid electrolyte and the active material can satisfy 0.03<E SE / E AM <0.11, the ratio between the shear modulus of the sulfide solid electrolyte and the active material can satisfy 0.05<G SE / G AM <0.12, further ensuring that the diaphragm maintains excellent properties in both mechanical and electrochemical properties.

[0049] According to one embodiment of the present disclosure, the ionic conductivity of the sulfide solid electrolyte is greater than 0.1mS / cm. In other words, the ionic conductivity σi of the sulfide solid electrolyte is selected from the system of σi>0.1mS / cm. Alternatively, the system of σi>1mS / cm, preferably, the system of σi>5mS / cm. The present disclosure can further optimize the electrochemical performance of the membrane by selecting a system with high ionic conductivity in a sulfide solid electrolyte of the low elastic modulus and low hardness type. As an example, the ionic conductivity of the sulfide solid electrolyte is 0.2mS / cm, 0.5mS / cm, 1mS / cm, 2mS / cm, 5mS / cm, 6mS / cm, 8mS / cm, 10mS / cm, 15mS / cm, 20mS / cm, etc.

[0050] In some specific embodiments of the present disclosure, the ratio of the mass of the non-metallic element in the sulfide solid electrolyte to the total mass of the sulfide solid electrolyte is greater than 15%.

[0051] In addition to essential elements such as Li and S, the composition of the sulfide solid electrolyte also contains soft elements, which refer to one or more long-period non-metallic or semi-metallic elements including Sb, Sn, Te, Se, I, Br, etc. The ratio of the mass of the soft elements to the total mass of the electrolyte is greater than 15%, and a system greater than 25% can be preferred. As an example, the ratio of the mass of non-metallic elements in the sulfide solid electrolyte to the total mass of the sulfide solid electrolyte is 16%, 18%, 20%, 22%, 24%, 26%, 28%, 30%, etc.

[0052] It can be understood that the above soft element contents can be obtained through ICP testing.

[0053] The present invention adopts a soft sulfide solid electrolyte and combines it with a hard active material to prepare a composite electrode plate. By starting from the elemental composition of the sulfide solid electrolyte, the elastic modulus of the sulfide solid electrolyte is controlled. The proportional relationship between the elastic modulus of the sulfide solid electrolyte and the elastic modulus of the active material is limited, so that the elastic modulus and shear modulus of the soft sulfide solid electrolyte and the hard active material meet the relationship of 0.03 < E SE / E AM <0.11,0.05<G SE / G AM <0.12, and finally a sulfide solid-state battery dry-process electrode with excellent tensile strength and good flexibility is prepared to achieve good performance of the solid-state battery.

[0054] In the present disclosure, the sulfide solid electrolyte can be 70Li2S-20P2S5-10LiI, Li 6-x PS 5-x Br 1+x (0≤X≤1), Li6SbS5I, Li7PS6Se 6-Y (0≤Y≤4), etc.

[0055] In the present disclosure, the active material includes a positive electrode active material. Positive electrode active materials have a higher hardness and are more suitable for the system in the present disclosure.

[0056] The positive electrode active material can be olivine, such as LiFePO4, etc. It can also be layered oxide, such as NCM, NCA or LiCoO2, etc. It can also be spinel, such as LiMn2O4, Li4Ti5O 12Etc. Soft sulfide solid electrolytes are paired with dry binders, which make it easier to achieve fiberization of the dry binder under high shear conditions, thereby improving the strength and flexibility of the membrane. The characteristics of soft sulfide solid electrolytes can be achieved by limiting the elemental composition of the electrolyte. During the fiberization process, the electrolyte particles can be further reduced. Combined with its low elastic modulus characteristics and the flexibility of the membrane, a higher density can be achieved after pressing. The high modulus active material can ensure that it maintains its original state during the fiberization process without being destroyed by shear force, thereby maintaining the stability of its performance.

[0057] In summary, according to the diaphragm of the embodiment of the present disclosure, the sulfide solid electrolyte adopts a soft solid electrolyte to ensure that the diaphragm can form a high degree of fiberization, and the strength of the forming after shearing is stronger and more uniform, thereby forming a diaphragm with excellent tensile strength and flexibility, effectively improving the strength and flexibility of the electrode, and is conducive to forming a diaphragm with higher density, thereby improving the performance of the diaphragm.

[0058] According to a second aspect of the present disclosure, a pole piece is provided, comprising the diaphragm described in the above embodiment, the pole piece further comprising a current collector, and the diaphragm is provided on at least one side of the current collector.

[0059] In other words, since the diaphragm according to the embodiment of the present disclosure has the above-mentioned technical effects, the pole piece according to the embodiment of the present disclosure should also have the corresponding technical effects. Specifically, the diaphragm in the pole piece of the present disclosure is mainly composed of a sulfide solid electrolyte and an active material, wherein the sulfide solid electrolyte adopts a soft solid electrolyte. In the dry film making process, after the binder powder and the solid electrolyte and the active material are mixed, under high shear conditions, the binder is formed into a huge number of fibrous filaments and intertwined with the electrolyte and the active material, and then a diaphragm is formed by rolling and the like. However, in the dry film making process for different inorganic particles (with different hardness and softness), the shear force required for the fiberization of the binder and the degree of fiberization after shearing will cause a large difference in the strength of the film. As far as the current sulfide solid electrolyte and active material system is concerned, dry film making has problems such as difficulty in film making and low film strength.

[0060] The membrane of the present disclosure can be arranged on at least one side of the current collector, and the pole piece made by using the membrane, wherein the sulfide solid electrolyte can adopt a soft solid electrolyte, can realize the full fiberization of the binder, and is conducive to increasing the bonding force between the membrane and the current collector. Among them, the soft solid electrolyte here refers to the elastic modulus E SE <30GPa type shear modulus G SESolid electrolytes with a pressure of less than 12GPa. During the fiberization stage of the electrode sheet, the soft sulfide solid electrolyte undergoes a certain degree of refinement under high shear forces. This smaller particle size facilitates better filling of the gaps between the composite active materials during the later molding and compaction process. Combined with the soft sulfide solid electrolyte's low elastic modulus, high degree of fiberization of the electrode sheet, and high flexibility, this facilitates the formation of a denser and more stable electrode structure, facilitating the conduction of lithium ions within the electrode sheet and improving electrode and battery performance.

[0061] Therefore, according to the diaphragm of the embodiment of the present disclosure, the sulfide solid electrolyte adopts a soft solid electrolyte, and the active material adopts a hard active material, ensuring that the sulfide solid electrolyte and the active material can form a high degree of fiberization during the fiberization process, and the strength of the formed part after shearing is stronger and more uniform, thereby forming a pole piece with excellent tensile strength and flexibility, effectively improving the strength and flexibility of the pole piece, and facilitating the formation of a higher density pole piece, thereby improving the performance of the pole piece.

[0062] According to a third aspect of the present disclosure, a method for preparing a pole piece is provided, the method comprising:

[0063] S1, mixing active materials, solid electrolytes, binders and conductive agents to form mixed powder; wherein the elastic modulus E of the sulfide solid electrolyte is SE <30GPa, the shear modulus G of the sulfide solid electrolyte SE <12 GPa, the sulfide solid electrolyte includes Li and S, and the sulfide solid electrolyte also includes at least one element of Sb, Sn, Te, Se, I, and Br.

[0064] S2, subjecting the mixed powder to a fiberization treatment under a shear force to obtain a treated powder;

[0065] S3, hot rolling the processed powder to prepare a membrane;

[0066] S4. Composite the membrane onto the current collector by hot pressing to prepare the electrode.

[0067] In other words, the preparation method disclosed herein adopts a dry film making method. Since the sulfide solid electrolyte will chemically react with high-polarity solvents such as H2O and NMP (N-methylpyrrolidone), the structure will be destroyed and the lithium conductivity will be lost. In the wet pulping process, even if low-polarity or non-polar solvents are used and matched with corresponding binders, although low-polarity, non-proton solvents will slow down the damage to the structure of the sulfide solid electrolyte to a certain extent, the adverse reaction between the solvent and the electrolyte cannot be completely avoided. In fact, even if such solvents are used to prepare sulfide solid electrolyte slurry, the attenuation of the ionic conductivity of the electrolyte is still obvious. It will still affect the quality of the electrode and the electrolyte membrane, and thus affect the performance of the battery.

[0068] It can be understood that the above-mentioned hot rolling treatment refers to subjecting the processed powder to hot pressing and / or hot rolling treatment.

[0069] The present disclosure adopts a dry preparation method, and the sulfide solid electrolyte can be a soft solid electrolyte, which can achieve sufficient fiberization of the binder, so that the prepared electrode has excellent tensile strength and good flexibility. Among them, the sulfide solid electrolyte can be a soft solid electrolyte with an elastic modulus E SE <30GPa, shear modulus G SE <12GPa solid electrolyte. During the fiberization stage of electrode preparation, the sulfide solid electrolyte undergoes a certain degree of particle refinement under high shear forces. This smaller particle size facilitates better filling of the gaps between composite cathode particles during the later molding and compaction process. Combined with the electrode's high fiberization and flexibility, this contributes to a denser electrode structure, facilitating lithium ion conduction within the composite cathode and improving electrode and battery performance.

[0070] The composition of the sulfide solid electrolyte disclosed herein includes, in addition to essential elements such as Li and S, soft elements, which refer to one or more long-period non-metallic or semi-metallic elements including Sb, Sn, Te, Se, I, Br, etc.

[0071] The active material used in the present disclosure can adopt an elastic modulus E AM >100GPa active materials, the active materials can use the shear modulus G AM Active materials with a high elastic modulus and high shear modulus can ensure that they maintain their original state during the fiberization process without being damaged by shear forces, thereby maintaining the stability of their performance.

[0072] In the preparation method disclosed herein, the active material, sulfide solid electrolyte, binder, and conductive agent are first mixed to form a mixed powder. The mixed powder can then be subjected to a fiberization treatment under shear force to obtain a processed powder. The processed powder can then be hot-rolled to produce a membrane. Finally, the membrane can be laminated onto a current collector by hot pressing to produce a pole piece, which serves as a positive electrode.

[0073] The present disclosure uses a soft sulfide solid electrolyte and an active material to prepare a dry-process electrode. This powder combination is used in the dry-process film-making process, which makes it easier to achieve sufficient fiberization of the binder, so that the prepared electrode has excellent tensile strength and good flexibility.

[0074] Therefore, according to the preparation method of the electrode of the embodiment of the present disclosure, it can ensure that the sulfide solid electrolyte and active material can form a high degree of fiberization during the fiberization process, and the strength of the formed part after shearing is stronger and more uniform, thereby forming an electrode with excellent tensile strength and flexibility, effectively improving the strength and flexibility of the electrode, and facilitating the formation of a higher density electrode, thereby improving the performance of the electrode.

[0075] According to one embodiment of the present disclosure, the elastic modulus E of the active material AM >100GPa, shear modulus of active material G AM >50GPa. The active material disclosed herein can be a hard active material, which can ensure that the original state of the active material is maintained during the fiberization process without being damaged by shear force, thereby maintaining the stability of its performance. The hard active material here refers to the elastic modulus E AM >100GPa, shear modulus G AM Active material types >50GPa.

[0076] According to one embodiment of the present disclosure, the binder is one or more of PTFE, PVDF, PAA, polyacrylate, NBR, and SBR to ensure that the binder can effectively achieve fiberization. The conductive agent is one or more of acetylene black, carbon nanotubes, carbon fibers, and carbon black.

[0077] According to one embodiment of the present disclosure, the shear force is generated by ball milling, air milling, kneading, screw extrusion, high-speed dispersion, degassing or ultrasound, which is simple and easy to operate.

[0078] According to one embodiment of the present disclosure, the hot rolling temperature is 120° C. to 230° C., which is conducive to hot rolling thinning of the high shear treated powder.

[0079] In the present disclosure, the degree of binder fiberization after high shear of the mixed powder can be observed using a scanning electron microscope (SEM) to measure the diameter and number of binder fibers. Elastic modulus and shear modulus can be measured using a nanoindenter. The tensile strength of the electrode can be measured using a tensile testing machine.

[0080] Specifically, the present disclosure can characterize the electrochemical properties of the electrode through a powder-type half-cell, and the counter electrode can be a lithium-indium alloy. The specific preparation method is: first cut the prepared electrode sheet and lithium-indium alloy sheet into small discs of φ15mm respectively. In a glove box with an argon atmosphere, 200mg of electrolyte powder is weighed and pressed into an electrolyte sheet at 120MPa using a φ15mm mold. An electrode disc is added to one side of the electrolyte sheet, and a pressure of 380MPa is applied as the working electrode. A lithium-indium alloy sheet is placed on the other side as the counter electrode to assemble into a half-cell. The mold battery assembled by the above method was subjected to constant current charge and discharge tests using the Landian multi-channel charge and discharge test system (LAND CT2001A).

[0081] The method for preparing the pole piece of the present disclosure is described below with reference to specific implementations.

[0082] Example 1

[0083] Elastic modulus test:

[0084] (1) Select LiNi 0.9 Co 0.05 Mn0 .05 O2 as active material, Li6PS5Cl 0.5 Br 0.5 As a solid electrolyte. Weigh Li6PS5Cl 0.5 Br 0.5 200mg of electrolyte powder was pressed into small discs in a 15mm φ tungsten carbide mold at a pressure of 600MPa. The elastic modulus and shear modulus were measured using a nanoindenter.

[0085] (2) Preparation of dry membrane:

[0086] Accurately weigh the active positive electrode LiNi 0.9 Co 0.05 Mn 0.05 O2, sulfide solid electrolyte Li6PS5Cl 0.5 Br 0.5 80g, 20g, 1.5g, and 0.5g of the binder PTFE (polytetrafluoroethylene), and the conductive agent Super P, respectively, were placed in a zirconia-lined ball milling jar along with 100g of zirconia ball milling beads. The mixture was uniformly mixed and sheared using a ball mill at 400 RPM for 1 hour.

[0087] The high-speed sheared and evenly mixed powder is then hot-rolled on a hot roller press to form a 600µm thick membrane. This is then further hot-rolled to reduce the membrane thickness to 100µm, resulting in the desired membrane. The hot-rolling temperature used in this process is 145°C.

[0088] (3) Diaphragm tensile strength test:

[0089] The membrane obtained in part (2) was cut into a rectangle with a width of 4 cm and a length of 7 cm, and the tensile strength of the membrane was tested using a universal tensile testing machine.

[0090] (4) Electrode preparation and membrane peeling force test:

[0091] Take the membrane obtained in part (2), use a hot roller press heated at 90°C to composite the membrane on a carbon-coated aluminum foil current collector to obtain a dry-process electrode, and use a peel force tester to test the electrode peel force.

[0092] (5) Electrochemical performance test of electrode:

[0093] Take the membrane prepared in part (2) and prepare the electrode using the same method as (4). Cut the prepared electrode and lithium indium alloy sheet into small discs of φ15 mm respectively. Weigh 200 mg of electrolyte powder in a glove box with an argon atmosphere and press it into an electrolyte sheet using a φ15 mm mold at 120 MPa. Add an electrode disc to one side of the electrolyte sheet and apply a pressure of 380 MPa as the working electrode. Place a lithium indium alloy sheet on the other side as the counter electrode to assemble into a half-cell. Use the Landian multi-channel charge and discharge test system (LAND CT2001A) to perform constant current charge and discharge tests on the mold battery assembled by the above method to obtain the electrochemical properties of the electrode.

[0094] Example 2

[0095] Same as Example 1, except that the electrolyte 70Li2S-20P2S5-10LiI is used instead of the electrolyte Li6PS5Cl 0.5 Br 0.5 .

[0096] Example 3

[0097] Same as Example 1, except that the electrolyte Li 6.4 Ge 0.4 Sb 0.6 S5I replaces Li6PS5Cl electrolyte 0.5 Br - 0.5 .

[0098] Example 4

[0099] Same as Example 1, except that the active positive electrode LiCoO2 is used instead of the active positive electrode LiNi 0.9 Co 0.05 Mn 0.05 O2.

[0100] Example 5

[0101] Same as Example 1, except that the active positive electrode LiCoO2 is used instead of the active positive electrode LiNi 0.9 Co 0.05 Mn 0.05 O2. Using electrolyte Li 6.7 Si 0.7 Sb0 .3 S5I replaces Li6PS5Cl electrolyte 0.5 Br 0.5 .

[0102] Example 6

[0103] Same as Example 1, except that the active positive electrode LiCoO2 is used instead of the active positive electrode LiNi 0.9 Co 0.05 Mn 0.05 O2. Using electrolyte Li6PS 3.7 Se 1.3 Br replaces the electrolyte Li6PS5Cl 0.5 Br 0.5 .

[0104] Example 7

[0105] Same as Example 1, except that the amount of PTFE added is 2.5% and the electrolyte Li is used. 5.3 PS 4.3 ClBr 0.7 Replace electrolyte Li6PS5Cl0 .5 Br 0.5 .

[0106] Example 8

[0107] Same as Example 1, except that the active positive electrode LiCoO2 is used instead of the active positive electrode LiNi 0.9 Co 0.05 Mn 0.05 O2, electrolyte Li 10 SnP2S 12 Replace electrolyte Li6PS5Cl0 .5 Br 0.5 .

[0108] Example 9

[0109] Same as Example 1, except that the electrolyte Li 10 SnP2S 12 Replace electrolyte Li6PS5Cl0 .5 Br 0.5 .

[0110] Example 10

[0111] Same as Example 1, except that the active positive electrode LiNi 0.6 Co 0.2 Mn 0.2 The combined material of O2 and LiFeMnPO4, the mass ratio of the combined material is 1:1, replacing the active positive electrode LiNi 0.9 Co 0.05 Mn 0.05 O2; at the same time, the binder content is 2.5%, while reducing the corresponding amount of positive electrode material.

[0112] Comparative Example 1

[0113] Same as Example 1, except that the electrolyte Li6PS5Cl is used instead of Li6PS5Cl 0.5 Br 0.5 .

[0114] Comparative Example 2

[0115] Same as Example 1, except that LiCoO2 is used as the active positive electrode instead of LiNi 0.9 Co 0.05 Mn 0.05 O2, using electrolyte Li2SiS3 instead of electrolyte Li6PS5Cl 0.5 Br 0.5 .

[0116] At the same time, the present disclosure has carried out a series of performance characterization tests according to various embodiments and comparative examples, wherein Table 1 is E SE 、E AM , G SE , G AM Test, Table 2 is the tensile strength, maximum force point deformation, and pole piece peeling force test, and Table 3 is the performance test of the positive electrode prepared battery.

[0117] Table 1 is E SE 、E AM , G SE , G AM test:

[0118] Table 2 shows the pole piece tensile strength, maximum force point deformation, and pole piece peeling force test:

[0119] Table 3 Performance test of battery prepared with positive electrode sheet:

[0120] As shown in Tables 1, 2, and 3, the present disclosure utilizes a soft sulfide solid electrolyte in combination with an active material for dry-process electrode preparation. This powder combination facilitates sufficient fiberization of the binder during dry-process sheeting, resulting in a prepared electrode with excellent tensile strength and flexibility. The sulfide solid electrolyte and active material achieve a high degree of fiberization during the fiberization process, resulting in a stronger and more uniform post-shear forming process. This results in an electrode with excellent tensile strength and flexibility, effectively improving both its strength and flexibility, leading to a denser electrode and enhanced electrode and battery performance.

[0121] Therefore, the present disclosure adopts a dry preparation method, the sulfide solid electrolyte can be a soft solid electrolyte, and the active material can be a hard active material, which can achieve sufficient fiberization of the binder, so that the prepared electrode has excellent tensile strength and good flexibility. Among them, the solid electrolyte can be an elastic modulus E SE Solid electrolytes of the type <30GPa, solid electrolytes can use shear modulus G SE Solid electrolyte with elastic modulus E<12GPa. AM >100GPa active materials, the active materials can use the shear modulus G AM >50GPa active materials. During the fiberization stage of the electrode sheet, the sulfide solid electrolyte will undergo a certain degree of refinement under the action of high shear force. The smaller particle size makes it easier to better fill the gaps between the composite positive electrode particles during the later molding and compaction process. In addition, the low elastic modulus, high fiberization degree of the electrode sheet, and high flexibility of the sulfide solid electrolyte are conducive to the formation of a denser electrode structure, which is conducive to the conduction of Li ions in the composite positive electrode and the improvement of the performance of the electrode and battery. The active material with high elastic modulus and high shear modulus can ensure that it maintains its original state during the fiberization process without being destroyed by shear force, thereby maintaining its stable performance.

[0122] According to a fourth aspect of the present disclosure, a battery is provided, comprising the electrode piece of the aforementioned embodiment, wherein the electrode piece is prepared using the electrode piece preparation method of the aforementioned embodiment. Since the electrode piece prepared using the preparation method according to the embodiment of the present disclosure has the aforementioned technical effects, the battery according to the embodiment of the present disclosure should also have the corresponding technical effects, that is, the battery according to the embodiment of the present disclosure using the electrode piece can effectively improve the performance of the battery.

[0123] Of course, for those skilled in the art, other structures of the battery and their working principles are understandable and achievable, and will not be described in detail in this disclosure.

[0124] According to a fifth aspect of the embodiments of the present disclosure, an electrical device is provided, comprising the battery of the above-described embodiment. Since the battery of the embodiments of the present disclosure has the above-described technical effects, the electrical device of the embodiments of the present disclosure should also have corresponding technical effects, namely, the use of the electrode in the electrical device of the embodiments of the present disclosure can effectively improve the endurance of the electrical device.

[0125] Of course, for those skilled in the art, other structures and working principles of the electrical equipment are understandable and achievable, and will not be described in detail in this disclosure.

[0126] Although some specific embodiments of the present disclosure have been described in detail through examples, those skilled in the art will appreciate that the above examples are for illustration only and are not intended to limit the scope of the present disclosure. Those skilled in the art will appreciate that modifications may be made to the above embodiments without departing from the scope and spirit of the present disclosure. The scope of the present disclosure is defined by the appended claims.

Claims

1. A diaphragm, wherein: It comprises a sulfide solid electrolyte, an active material and a binder, wherein the elastic modulus E of the sulfide solid electrolyte is SE <30GPa, the shear modulus G of the sulfide solid electrolyte SE <12 GPa, the sulfide solid electrolyte includes Li and S, and the sulfide solid electrolyte also includes at least one element of Sb, Sn, Te, Se, I, and Br.

2. The diaphragm according to claim 1, wherein The elastic modulus E of the active material AM >100 GPa, the shear modulus G of the active material AM >50GPa.

3. The diaphragm according to claim 1 or 2, wherein: The active material is a positive electrode active material.

4. The diaphragm according to any one of claims 1 to 3, wherein The elastic modulus E of the sulfide solid electrolyte SE <18GPa, the shear modulus G of the sulfide solid electrolyte SE <8GPa.

5. The diaphragm according to claim 2, wherein The ratio between the elastic modulus of the sulfide solid electrolyte and the active material is 0.03<E SE / E AM <0.11, the ratio between the shear modulus of the sulfide solid electrolyte and the active material is 0.05 <G SE / G AM <0.

12.

6. The diaphragm according to any one of claims 1 to 5, wherein The ionic conductivity of the sulfide solid electrolyte is greater than 0.1 mS / cm.

7. The diaphragm according to any one of claims 1 to 6, wherein The ratio of the mass of the non-metallic elements in the sulfide solid electrolyte to the total mass of the sulfide solid electrolyte is greater than 15%.

8. A pole piece, wherein: The invention comprises the membrane according to any one of claims 1 to 7, and further comprises a current collector, wherein the membrane is provided on at least one side of the current collector.

9. A method for preparing a pole piece, wherein: The preparation method comprises: The active material, the sulfide solid electrolyte, the binder and the conductive agent are mixed to form a mixed powder; wherein the elastic modulus E of the sulfide solid electrolyte is SE <30GPa, the shear modulus G of the sulfide solid electrolyte SE <12 GPa, the sulfide solid electrolyte includes Li and S, and the sulfide solid electrolyte further includes: at least one element of Sb, Sn, Te, Se, I, Br; The mixed powder is subjected to a fiberizing treatment under the action of a shear force to obtain a treated powder; The processed powder is subjected to hot rolling to prepare a membrane; The film is composited on the current collector by hot pressing to prepare a pole piece.

10. The method for preparing a pole piece according to claim 9, wherein: The elastic modulus E of the active material AM >100 GPa, the shear modulus G of the active material AM >50GPa.

11. The method for preparing a pole piece according to claim 9 or 10, wherein: The binder is one or more of polytetrafluoroethylene, polyvinylidene fluoride, polyacrylic acid, polyacrylate, nitrile rubber, and styrene-butadiene rubber; the conductive agent is one or more of acetylene black, carbon nanotubes, carbon fibers, and carbon black.

12. The method for preparing a pole piece according to any one of claims 9 to 11, wherein: The shear force is generated by ball milling, air milling, kneading, screw extrusion, high-speed dispersion, degassing or ultrasound.

13. The method for preparing a pole piece according to any one of claims 9 to 12, wherein: The hot rolling temperature is 120°C to 230°C.

14. A battery, wherein: The invention comprises the pole piece according to claim 8, or comprises a pole piece made by the pole piece preparation method according to any one of claims 9 to 13.

15. An electrical device, wherein: A battery comprising the battery of claim 14; or a pole piece, wherein the pole piece is the pole piece of claim 8 or a pole piece made by the method for making the pole piece of any one of claims 9 to 13.

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