A novel dry-method electrolyte membrane, and a preparation method and application thereof

Abstract

This invention provides a novel dry-process electrolyte membrane, its preparation method, and its application, belonging to the field of solid-state battery technology. The electrolyte membrane is prepared by a dry film-forming process after combining a highly elastic and viscous halide with a solid electrolyte; the highly elastic and viscous halide includes Li3McXb6, derivatives of Li3McXb6, and Li... x Md y N 1‑ y Cl q and Li x Md y N 1‑y Cl q The electrolyte membrane comprises at least one of the following derivatives: Mc, In, Al, Ti, Y, Dy, Gd, Ge, Sc, Zr, and Yb; and Md comprises at least one of In, Y, Al, Zr, Sc, and Ge. This electrolyte membrane exhibits low porosity and high tensile strength, with a more compact internal structure, reducing internal defects in the battery. The increased tensile strength suppresses lithium dendrite penetration, preventing internal short circuits and thus achieving superior battery cycle performance.

Description

Technical Field

[0001] This invention belongs to the field of solid-state battery technology, and specifically relates to a novel dry-process electrolyte membrane, its preparation method, and its application. Background Technology

[0002] With technological advancements and increasing demand for sustainable energy, solid-state batteries have garnered widespread attention due to their unique advantages. While traditional liquid lithium-ion batteries are widely used, they suffer from limitations such as energy density limitations, safety risks posed by lithium dendrite formation, reduced cycle life due to solid electrolyte interphase (SEI) thickening, and insufficient low-temperature performance. Solid-state batteries, which use solid electrolytes instead of liquid electrolytes, offer significant advantages including high energy density, rapid charge / discharge capabilities, excellent safety performance, and long cycle life, making them a highly desirable candidate to replace traditional liquid lithium-ion batteries.

[0003] Solid-state battery materials can be categorized into positive electrode materials, solid electrolytes, and negative electrode materials based on their roles within the battery. The positive and negative electrode materials serve as carriers for lithium ions to be extracted and inserted during electrochemical cycling. Their operating voltage, theoretical specific capacity, and conductivity directly impact the battery's energy density and power density. The solid electrolyte plays a crucial role in solid-state batteries; it is the key medium connecting the positive and negative electrodes and is responsible for lithium ion transport.

[0004] Compared to traditional liquid electrolytes, solid-state electrolyte membranes (SSMEs) offer several significant advantages. First, SSMEs greatly enhance battery safety. Liquid electrolytes are flammable and volatile, and during charging and discharging, lithium dendrites can penetrate the separator, causing short circuits, thermal runaway, and even fires. Solid-state electrolyte membranes, on the other hand, are not easily flammable and effectively inhibit lithium dendrite growth, maintaining battery stability even under extreme conditions and significantly reducing safety risks. Second, SSMEs help increase battery energy density. Their excellent mechanical properties and high ionic conductivity allow for thinner electrolyte layers, increasing the proportion of active material in the battery. Simultaneously, SSMEs can support higher-voltage cathode materials, further enhancing the battery's energy output. Finally, SSMEs improve battery cycle life. Liquid electrolytes may decompose over long-term use, forming an SEI film, leading to increased internal resistance and capacity decay. Solid-state electrolyte membranes are relatively stable and less prone to chemical decomposition, thus extending battery life. The use of SSMEs also provides greater flexibility in battery shape design and packaging. It can be made into various forms such as thin film, sheet or block, which can better adapt to the shape requirements of different devices and realize the customized design of batteries.

[0005] There are two main methods for preparing all-solid-state electrolyte membranes: wet coating and dry film formation. Wet coating involves high-speed stirring and dispersion of inorganic solid electrolyte materials, binders, and organic solvents to prepare a uniform slurry for coating. This process is simple, feasible, and technically mature. However, most inorganic solid electrolytes are unstable to water, oxygen, and organic solvents, leading to deterioration of the solid electrolyte material and failure to meet ionic conductivity requirements. Dry film formation avoids the use of solvents. It primarily involves fiberizing the solid electrolyte powder and binder, using the binder fibers to construct a network-like framework to support the solid electrolyte powder, and then rolling to form a film.

[0006] However, solid electrolyte membranes produced by dry film-forming rollers often suffer from numerous surface pores, inability to thin the membrane, susceptibility to cracking, or low ionic conductivity. Assembling batteries using solid electrolyte membranes with many surface pores will cause contact failure at the interface between the positive and negative electrodes and the solid electrolyte membrane, leading to poor battery performance and even lithium plating short circuits. Furthermore, excessive thickness of the solid electrolyte membrane will affect the battery's energy density and reduce battery performance.

[0007] To address the aforementioned technical deficiencies, patent CN120818320A discloses a composite binder, an electrolyte membrane, a preparation method, and a battery. The composite binder described in this patent comprises a binder main material and crosslinked molecules. It utilizes reversible chemical bonds or heat-sensitive functional groups contained in the main chain of the crosslinked molecules to solve the problem of poor mechanical properties of the binder in the electrolyte membrane. While this method improves the mechanical properties of the electrolyte membrane, the amount of binder added is relatively small, only 0.5-1.5%, which cannot solve the problem of high porosity in the electrolyte membrane. Furthermore, the use of organic solvents in the binder preparation process causes environmental pollution and high solvent recovery costs, and the preparation process is complex.

[0008] Patent CN118431552A discloses a solid electrolyte membrane, its preparation method, and a solid-state battery. The electrolyte membrane described in this patent utilizes two solid electrolytes of different particle sizes to form a film. A second film layer is stacked on the upper and lower surfaces of the first film layer and then co-rolled to reduce the surface porosity of the resulting solid electrolyte membrane, thereby improving ionic conductivity and tensile strength. This method uses two electrolyte membranes of different particle sizes for a three-layer co-rolling process, which reduces porosity and optimizes tensile strength. However, the thickness of the three-layer electrolyte membrane cannot be effectively reduced during calendering, and the particle size of the solid electrolytes needs to be sieved before preparation, making the preparation process cumbersome.

[0009] Patent CN120767387A discloses a dry-process solid electrolyte membrane, its preparation method, and its applications. This patent improves the transverse and longitudinal tensile strength, ionic conductivity, and cycle performance of the electrolyte membrane by adding a high proportion of lithium-ion polymers. While this method overcomes the problems of thinner dry-process solid electrolyte membranes being prone to cracking, lacking self-support, and having poor contact between the solid electrolyte membrane and the electrode interface in existing technologies, the added lithium-ion polymer has low ionic conductivity (≥10). -6 The high proportion of binder added to the electrolyte membrane (S / cm) leads to a decrease in the ionic conductivity of the electrolyte membrane and increases interfacial side reactions during battery cycling.

[0010] In summary, there is a need to develop a solid electrolyte membrane with low porosity and high mechanical properties to achieve high energy density and high safety of all-solid-state batteries in various application fields. Summary of the Invention

[0011] To address the issues of high porosity, insufficient mechanical properties, and inadequate cycle performance in existing dry-process electrolyte membranes, this invention provides a novel dry-process electrolyte membrane with low porosity and high tensile strength. Its internal structure is more compact, reducing internal battery defects. The increased tensile strength can suppress lithium dendrite penetration, prevent internal short circuits, and thus achieve superior battery cycle performance.

[0012] The present invention also provides a novel dry-process electrolyte membrane preparation method and its application.

[0013] This invention is achieved through the following technical solution:

[0014] This invention provides a novel dry-process electrolyte membrane, which is prepared by a dry film-forming process after a high-elasticity viscous halide is combined with a solid electrolyte.

[0015] The highly elastic viscous halides include Li3McXb6, derivatives of Li3McXb6, and Li x Md y N 1-y Cl q and Li x Md y N 1- y Cl q At least one of the derivatives;

[0016] Wherein, Mc includes at least one of In, Al, Ti, Y, Dy, Gd, Ge, Sc, Zr and Yb, Md includes at least one of In, Y, Al, Zr, Sc and Ge, N includes at least one of Yb, Ti, Dy and O, Xb includes at least one of F, Cl, Br and I, 0 < x ≤ 3, 0 < q ≤ 6, 0 < y ≤ 1;

[0017] The solid electrolyte includes any one of sulfide solid electrolyte, halide solid electrolyte, and oxide solid electrolyte;

[0018] The mass ratio of the highly elastic viscous halide to the solid electrolyte is (1 / 9 to 9):1.

[0019] Optionally, the sulfide solid electrolyte includes Li6PS5Xa, derivatives of Li6PS5Xa, and Li 6+a Sb 1- a Si a S5I, Li 6+a Sb 1-a Si a S5I derivatives, Li 10 MaP2S 12 Li 10 MaP2S 12 Derivatives of Li3PS4, Li3PS4 derivatives, Li7P3S 11 Li7P3S 11 At least one of the following: derivatives of Li4MbS4 and derivatives of Li4MbS4;

[0020] Wherein, Xa includes at least one of F, Cl, Br and I, Ma includes at least one of Si, Ge, Sn, Zn and Al, Mb includes any one of Si, Sn and Ge, and 0.1≤a≤0.75.

[0021] Optionally, the halide solid electrolyte includes Li3McXb6, derivatives of Li3McXb6, and Li x Md y N 1-y Cl q and Li x Md y N 1-y Cl q At least one of the derivatives;

[0022] Wherein, Mc includes at least one of In, Al, Ti, Y, Dy, Gd, Ge, Sc, Zr and Yb, Md includes at least one of In, Y, Al, Zr, Sc and Ge, N includes at least one of Yb, Ti, Dy and O, Xb includes at least one of F, Cl, Br and I, 0 < x ≤ 3, 0 < q ≤ 6, 0 < y ≤ 1.

[0023] Optionally, the oxide solid electrolyte includes at least one of perovskite oxide, NASICON oxide, LISICON oxide, and garnet oxide.

[0024] Based on the same inventive concept, this invention provides a novel dry-process method for preparing electrolyte membranes, the method comprising:

[0025] The high-elasticity viscous halide and solid electrolyte are mixed evenly, and then heated and kept at a certain temperature to obtain the mixture.

[0026] After adding polytetrafluoroethylene to the mixture, a fibrous treatment is performed to obtain a composite solid electrolyte group;

[0027] The composite solid electrolyte clusters are rolled into a film to obtain the novel dry electrolyte membrane.

[0028] Furthermore, the process of uniformly mixing the high-elasticity viscous halide and the solid electrolyte, followed by heating and holding at a certain temperature to obtain a mixture specifically includes: uniformly mixing the high-elasticity viscous halide and the solid electrolyte by ball milling, hand milling, or stirring, and then heating to 30-200°C under an inert atmosphere and holding at that temperature for 0.5-2 hours to obtain a mixture;

[0029] The mass ratio of the highly elastic viscous halide to the solid electrolyte is (1 / 9 to 9):1;

[0030] In the mixture, the particle size distribution of the highly elastic viscous halide and the solid electrolyte is 0.1–10 μm.

[0031] Furthermore, the step of adding polytetrafluoroethylene to the mixture and then subjecting it to fibrosis to obtain composite solid electrolyte clusters specifically includes:

[0032] After adding polytetrafluoroethylene to the mixture, mechanical stirring or manual grinding is performed to obtain composite solid electrolyte clusters;

[0033] The mass of the polytetrafluoroethylene is 0.1% to 3% of the mass of the mixture;

[0034] The mechanical stirring speed is 300-3000 rpm, and the stirring time is 0.1-1 h;

[0035] The manual grinding time is 5 to 20 minutes.

[0036] Furthermore, the step of rolling the composite solid electrolyte clusters into a film to obtain the novel dry-process electrolyte membrane specifically includes:

[0037] The composite solid electrolyte agglomerates are rolled into a film with a roller temperature of 100±10℃ and a pressure of 1.5t~3t to obtain the novel dry electrolyte membrane.

[0038] The thickness of the novel dry-process electrolyte membrane is 30–300 μm;

[0039] The highly elastic viscous halides include Li3McXb6, derivatives of Li3McXb6, and Li x Md y N 1-y Cl q and Li x Md y N 1- y Cl q At least one of the derivatives;

[0040] Wherein, Mc includes at least one of In, Al, Ti, Y, Dy, Gd, Ge, Sc, Zr and Yb, Md includes at least one of In, Y, Al, Zr, Sc and Ge, N includes at least one of Yb, Ti, Dy and O, Xb includes at least one of F, Cl, Br and I, 0 < x ≤ 3, 0 < q ≤ 6, 0 < y ≤ 1;

[0041] The solid electrolyte includes any one of sulfide solid electrolyte, halide solid electrolyte, and oxide solid electrolyte.

[0042] Based on the same inventive concept, this invention provides an application of a novel dry-process electrolyte membrane in the preparation of all-solid-state batteries.

[0043] Based on the same inventive concept, the present invention provides an all-solid-state battery, wherein the all-solid-state battery contains the above-mentioned novel dry-process electrolyte membrane.

[0044] Furthermore, the all-solid-state battery is a primary battery or a secondary battery, and the secondary battery includes any one of pouch batteries, prismatic batteries, and cylindrical batteries.

[0045] One or more technical solutions in the embodiments of the present invention have at least the following technical effects or advantages:

[0046] 1. This invention discloses a novel dry-process electrolyte membrane, which is prepared by a dry process combining a highly elastic and viscous halide with a solid electrolyte. The low-melting-point, highly elastic and viscous halide serves as the fusible / binding phase. Under appropriate heating conditions, the fusible phase partially melts and penetrates into the pores of the electrolyte membrane, densifying and strengthening the membrane. After cooling, a continuous solid phase is formed, resulting in a dry-process electrolyte membrane with both high ion conductivity and high mechanical stability. This invention improves the mechanical properties of the electrolyte membrane by designing a reasonable composite electrolyte ratio, solving the problems of poor tensile strength and inability to reduce thickness in electrolyte membranes prepared by traditional processes. Using a thinner solid electrolyte membrane reduces the proportion of solid electrolyte in the battery, thereby increasing the battery's energy density and demonstrating significant application potential.

[0047] 2. This invention discloses a novel dry-process electrolyte membrane with low porosity and high tensile strength. By adding highly elastic and viscous halides, combined with a simple preparation process, and selecting a suitable solid electrolyte, the porosity of the electrolyte membrane is reduced and the tensile strength is increased. This achieves high energy density and high safety for all-solid-state batteries in a wide range of applications. The internal structure of this novel dry-process electrolyte membrane is more compact, reducing internal defects in the battery. The increased tensile strength can suppress lithium dendrite penetration and prevent internal short circuits, thereby achieving superior battery cycle performance.

[0048] 3. This invention discloses a novel dry-process electrolyte membrane. This electrolyte membrane, through a rationally designed composite electrolyte ratio, reduces the membrane porosity, thereby decreasing ion transport tortuosity and improving battery electrochemical performance. Simultaneously, the use of a dry film-forming process to prepare the solid electrolyte membrane avoids the use of organic solvents, reducing production costs and preventing environmental pollution, thus possessing broad application prospects. This electrolyte membrane can be matched with various positive and negative electrode materials for use in inorganic solid-state batteries, offering advantages such as high energy density, high safety, simple preparation process, and low cost. It has significant application value, especially in the field of solid-state pouch batteries.

[0049] 4. This invention discloses a novel dry-process electrolyte membrane preparation method. The method involves mixing a highly elastic and viscous halide with a solid electrolyte, adding a small amount of PTFE (polytetrafluoroethylene), stirring to induce fibrosis, and finally rolling the mixture using a roller press to prepare the electrolyte membrane. This method can improve the problem of high porosity in the traditional dry-process electrolyte membrane preparation process, effectively reduce the ion transport impedance between solid electrolyte particles, and improve the ionic conductivity of the electrolyte membrane. This method can also improve the tensile strength of the dry-process electrolyte membrane while reducing the amount of non-conductive lithium binder used. Attached Figure Description

[0050] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0051] Figure 1 The first charge-discharge curve of the all-solid-state battery in Example 1 is shown.

[0052] Figure 2 This is the first charge-discharge curve of the all-solid-state battery in Example 2.

[0053] Figure 3 This is the first charge-discharge curve of the all-solid-state battery in Example 3.

[0054] Figure 4 This is the first charge-discharge curve of the all-solid-state battery in Example 4.

[0055] Figure 5 The first charge-discharge curve of the all-solid-state battery in Comparative Example 1 is shown.

[0056] Figure 6 SEM images of dry solid electrolyte membranes for Comparative Example 1, Example 1, and Example 3. Detailed Implementation

[0057] The present invention will be described in detail below with reference to specific embodiments and examples, thereby making the advantages and various effects of the present invention more clearly apparent. Those skilled in the art should understand that these specific embodiments and examples are for illustrative purposes only and are not intended to limit the present invention.

[0058] Throughout this specification, unless otherwise specified, the terminology used herein should be understood as having the meaning commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. In the event of any conflict, this specification shall prevail.

[0059] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0060] The technical principle of this invention is as follows:

[0061] This invention provides a novel dry-process electrolyte membrane, which is prepared by a dry film-forming process after a high-elasticity viscous halide is combined with a solid electrolyte.

[0062] The highly elastic viscous halides include Li3McXb6, derivatives of Li3McXb6, and Lix Md y N 1-y Cl q and Li x Md y N 1- y Cl q At least one of the derivatives;

[0063] Wherein, Mc includes at least one of In, Al, Ti, Y, Dy, Gd, Ge, Sc, Zr and Yb, Md includes at least one of In, Y, Al, Zr, Sc and Ge, N includes at least one of Yb, Ti, Dy and O, Xb includes at least one of F, Cl, Br and I, 0 < x ≤ 3, 0 < q ≤ 6, 0 < y ≤ 1;

[0064] The solid electrolyte includes any one of sulfide solid electrolyte, halide solid electrolyte, and oxide solid electrolyte;

[0065] The mass ratio of the highly elastic viscous halide to the solid electrolyte is (1 / 9 to 9):1.

[0066] In this invention, the highly elastic viscous halide is Li3McXb6, Li x Md y N 1-y Cl q and its derivatives, Li3McXb6, Li x Md y N 1-y Cl q Its derivatives have low melting point, high ionic conductivity and excellent viscoelasticity. When heated, they can soften and flow to fill the gaps between particles. When cooled, they form a continuous lithium-conducting phase, which takes into account both ion conduction and mechanical enhancement, and significantly reduces the porosity of the film.

[0067] In this invention, the mass ratio of the highly elastic viscous halide to the solid electrolyte is (1 / 9 to 9):1. Within this ratio range, the highly elastic viscous halide can fully fill the pores and form a continuous phase, while avoiding a decrease in ionic conductivity due to excessive content. When the mass ratio is less than 1:9, the viscous component is insufficient, resulting in poor densification and limited strength improvement; when it is greater than 9:1, the proportion of rigid solid electrolyte is too low, leading to a decrease in membrane heat resistance and structural stability, which is detrimental to long-term cycling.

[0068] Optionally, the sulfide solid electrolyte includes Li6PS5Xa, derivatives of Li6PS5Xa, and Li 6+a Sb 1- a Si a S5I, Li 6+a Sb1-a Si a S5I derivatives, Li 10 MaP2S 12 Li 10 MaP2S 12 Derivatives of Li3PS4, Li3PS4 derivatives, Li7P3S 11 Li7P3S 11 At least one of the following: derivatives of Li4MbS4 and derivatives of Li4MbS4;

[0069] Wherein, Xa includes at least one of F, Cl, Br and I, Ma includes at least one of Si, Ge, Sn, Zn and Al, Mb includes any one of Si, Sn and Ge, and 0.1≤a≤0.75.

[0070] Optionally, the halide solid electrolyte includes Li3McXb6, derivatives of Li3McXb6, and Li x Md y N 1-y Cl q and Li x Md y N 1-y Cl q At least one of the derivatives;

[0071] Wherein, Mc includes at least one of In, Al, Ti, Y, Dy, Gd, Ge, Sc, Zr and Yb, Md includes at least one of In, Y, Al, Zr, Sc and Ge, N includes at least one of Yb, Ti, Dy and O, Xb includes at least one of F, Cl, Br and I, 0 < x ≤ 3, 0 < q ≤ 6, 0 < y ≤ 1.

[0072] Optionally, the oxide solid electrolyte includes at least one of perovskite oxide, NASICON oxide, LISICON oxide, and garnet oxide.

[0073] In this invention, the solid electrolyte is the aforementioned inorganic solid electrolyte, which can be adapted to different requirements such as high ionic conductivity, high stability, and high mechanical strength. When combined with a highly elastic and viscous halide, it can synergistically optimize the ion conduction, interfacial compatibility, and mechanical properties of the membrane.

[0074] Based on the same inventive concept, this invention provides a novel dry-process method for preparing electrolyte membranes, the method comprising:

[0075] The high-elasticity viscous halide and solid electrolyte are mixed evenly, and then heated and kept at a certain temperature to obtain the mixture.

[0076] After adding polytetrafluoroethylene to the mixture, a fibrous treatment is performed to obtain a composite solid electrolyte group;

[0077] The composite solid electrolyte clusters are rolled into a film to obtain the novel dry electrolyte membrane.

[0078] In this invention, the purpose of heating and heat preservation after mixing the high-elasticity viscous halide and the solid electrolyte is that heating and heat preservation can initially soften the high-elasticity viscous halide and uniformly coat the solid electrolyte particles, reduce the interfacial resistance between particles, and at the same time improve the dispersion uniformity of PTFE fibers in the subsequent fiberization process, laying the foundation for dense film formation.

[0079] In this invention, polytetrafluoroethylene (PTFE) is added to the mixture. PTFE acts as a fibrous binder, forming a three-dimensional fiber network that imparts self-support and flexibility to the membrane. At the same time, the addition amount is low, so it has little impact on ionic conductivity.

[0080] Furthermore, the process of uniformly mixing the high-elasticity viscous halide and the solid electrolyte, followed by heating and holding at a certain temperature to obtain a mixture specifically includes: uniformly mixing the high-elasticity viscous halide and the solid electrolyte by ball milling, hand milling, or stirring, and then heating to 30-200°C under an inert atmosphere and holding at that temperature for 0.5-2 hours to obtain a mixture;

[0081] The mass ratio of the highly elastic viscous halide to the solid electrolyte is (1 / 9 to 9):1;

[0082] In the mixture, the particle size distribution of the highly elastic viscous halide and the solid electrolyte is 0.1–10 μm.

[0083] In this invention, the particle size distribution of the high-elasticity viscous halide and the solid electrolyte is 0.1–10 μm, which can achieve optimized particle size distribution. Small particles fill the gaps between large particles, and with the filling effect of the high-elasticity viscous halide, the membrane porosity is minimized to the maximum extent. At the same time, it avoids agglomeration caused by excessively small particle size and poor interfacial contact caused by excessively large particle size.

[0084] Furthermore, the step of adding polytetrafluoroethylene to the mixture and then subjecting it to fibrosis to obtain composite solid electrolyte clusters specifically includes:

[0085] After adding polytetrafluoroethylene to the mixture, mechanical stirring or manual grinding is performed to obtain composite solid electrolyte clusters;

[0086] The mass of the polytetrafluoroethylene is 0.1% to 3% of the mass of the mixture;

[0087] The mechanical stirring speed is 300-3000 rpm, and the stirring time is 0.1-1 h;

[0088] The manual grinding time is 5 to 20 minutes.

[0089] Furthermore, the step of rolling the composite solid electrolyte clusters into a film to obtain the novel dry-process electrolyte membrane specifically includes:

[0090] The composite solid electrolyte agglomerates are rolled into a film with a roller temperature of 100±10℃ and a pressure of 1.5t~3t to obtain the novel dry electrolyte membrane.

[0091] The thickness of the novel dry-process electrolyte membrane is 30–300 μm.

[0092] In this invention, the roller temperature is 100±10℃. A roller temperature of 100±10℃ allows for secondary softening of the highly elastic and viscous halide, improving particle flowability and interfacial adhesion. Excessive temperature can lead to excessive halide flow and film deformation, while insufficient temperature results in inadequate softening and poor densification. A pressure of 1.5t to 3t effectively compacts the particles and eliminates porosity. Insufficient pressure leads to insufficient compaction and low strength, while excessive pressure can cause particle breakage and ion conduction channel rupture.

[0093] In this invention, the advantage of having a thickness of 30–300 μm for the novel dry electrolyte membrane is that it can maximize the energy density of the battery, while 300 μm can ensure the mechanical strength and processing stability of the membrane, thus balancing energy density and safety.

[0094] The following will provide a detailed description of a novel dry-process electrolyte membrane, its preparation method, and its application, in conjunction with embodiments and experimental data.

[0095] Example 1

[0096] This embodiment provides a novel dry-process electrolyte membrane and solid-state battery preparation method.

[0097] 1. Preparation method of solid electrolyte membrane:

[0098] 1) The high-elasticity, viscous halide solid electrolyte Li 2.5 Al 0.5 O 0.5 Cl3 (LAOC) and sulfide solid electrolyte Li6PS5Cl (LPSC) particles were added to a mixer at a mass ratio of 1:9 and stirred at 300 rpm for 1.5 h to obtain a uniformly mixed composite solid electrolyte material with a particle size distribution of 0.5-5 μm.

[0099] 2) Under an inert atmosphere, the composite solid electrolyte material was kept at 80°C for 1 hour, and then 2% by mass of polytetrafluoroethylene (PTFE) was added. The mixture was stirred at 800 rpm for 15 minutes to fibrose the material and obtain the fibrous composite solid electrolyte mass.

[0100] 3) The obtained fibrous composite solid electrolyte mass was subjected to multiple horizontal and vertical hot rolling processes with a roller temperature of 100℃ and a constant pressure of 2t to obtain a uniform and dense solid electrolyte membrane with a thickness of 60μm.

[0101] 2. Assembly of solid-state molded batteries:

[0102] The composite solid electrolyte membrane obtained in step 1 is placed into a solid battery mold, and a pressure of 1t is applied and held for 1 minute. Composite cathode material powder (LiNi cathode material powder raw material) is added to the cathode side. 0.8 Co 0.1 Mn 0.1 O2 (NCM811), LPSC, and conductive carbon black SP (mass ratio of the three materials 70:30:2, total thickness approximately 100 μm) were applied under a pressure of 3t for 1 min. A Li-In alloy (Li:In mass ratio 50:50, thickness approximately 50 μm) was added to the negative electrode side and a pressure of 1t was applied for 30 s. The assembled mold battery was then subjected to electrochemical testing at a constant pressure of 300 MPa (using a Blue Battery testing system).

[0103] The solid electrolyte membrane in this embodiment was characterized by SEM, and charge-discharge tests were performed on the all-solid-state battery. First, activation was achieved by three charge-discharge cycles at a rate of 0.1C with a cutoff voltage of 1.9 V–3.7 V. Then, charge-discharge cycle tests were conducted at a rate of 0.3C with a cutoff voltage of 1.9 V–3.7 V. The test results are as follows. Figure 1 As shown.

[0104] Example 2

[0105] This embodiment provides a novel dry-process electrolyte membrane and solid-state battery preparation method.

[0106] 1. Preparation method of solid electrolyte membrane: Same as step 1 in Example 1.

[0107] 2. Assembly of solid-state pouch cells:

[0108] A composite positive electrode (100 μm thick) and a solid electrolyte membrane (60 μm thick) prepared in Example 1 were prepared using a dry process. The composite positive electrode was prepared using NCM ternary layered oxide positive electrode, Li6PS5Cl inorganic solid electrolyte, SP conductive agent, and PTFE binder (mass ratio 70:30:2:2). A double-sided coated silicon negative electrode (65 μm thick) was prepared using a wet coating process. The positive electrode, solid electrolyte membrane, and negative electrode were stacked sequentially, encapsulated with an aluminum-plastic film, subjected to a secondary final sealing, and isostatically pressed at 30 MPa to obtain a solid-state pouch cell. Electrochemical tests were performed using a Blue Battery testing system.

[0109] The solid electrolyte membrane in this embodiment was characterized by SEM, and charge-discharge tests were performed on the all-solid-state battery. First, activation was achieved by three charge-discharge cycles at a rate of 0.1C with a cutoff voltage of 1.9 V–3.7 V. Then, charge-discharge cycle tests were conducted at a rate of 0.3C with a cutoff voltage of 1.9 V–3.7 V. The test results are as follows. Figure 2 As shown.

[0110] Example 3

[0111] This embodiment provides a novel dry-process electrolyte membrane and solid-state battery preparation method.

[0112] 1. Preparation method of solid electrolyte membrane:

[0113] 1) The high-elasticity, viscous halide solid electrolyte Li 2.5 Al 0.5 O 0.5 Cl3 (LAOC) and sulfide solid electrolyte Li3PS4 (LPS) particles were added to a mixer at a mass ratio of 2:8 and stirred at 300 rpm for 1.5 h to obtain a uniformly mixed composite solid electrolyte material with a particle size distribution of 0.5-5 μm.

[0114] 2) Under an inert atmosphere, the composite solid electrolyte material was kept at 80°C for 1 hour, and then 2% by mass of polytetrafluoroethylene (PTFE) was added. The mixture was stirred at 800 rpm for 15 minutes to fibrose the material and obtain the fibrous composite solid electrolyte mass.

[0115] 3) The obtained fiberized composite solid electrolyte mass was subjected to multiple horizontal and vertical hot rolling processes, with the roller temperature at 100℃ and the pressure at a constant 2t, to obtain a uniform and dense solid electrolyte membrane with a thickness of 60μm.

[0116] 2. Assembly of solid-state molded batteries:

[0117] The composite solid electrolyte membrane (60 μm thick) prepared in step 1 was placed in a solid battery mold, and a pressure of 1t was applied and held for 1 min. Composite cathode material powder (LiNi) was then added to the positive electrode side. 0.8 Co 0.1 Mn 0.1 O2 (NCM811):LPS:SP = 70:30:2, thickness approximately 100μm) was applied under a pressure of 3t for 1 min. A Li-In alloy (Li:In mass ratio 50:50, thickness approximately 50μm) was added to the negative electrode side and a pressure of 1t was applied for 30 s. The assembled mold battery was then subjected to electrochemical testing at a constant pressure of 300MPa (using the Blue Battery testing system).

[0118] The solid electrolyte membrane in this embodiment was characterized by SEM, and charge-discharge tests were performed on the all-solid-state battery. First, activation was achieved by three charge-discharge cycles at a rate of 0.1C with a cutoff voltage of 1.9 V–3.7 V. Then, charge-discharge cycle tests were conducted at a rate of 0.3C with a cutoff voltage of 1.9 V–3.7 V. The test results are as follows. Figure 3 As shown.

[0119] Example 4

[0120] This embodiment provides a novel dry-process electrolyte membrane and solid-state battery preparation method.

[0121] 1. Preparation method of solid electrolyte membrane:

[0122] 1) Highly elastic and viscous halide solid electrolyte Li3AlCl6 and sulfide solid electrolyte Li6PS5Cl (LPSC) particles were added into a mixer at a mass ratio of 1:9 and stirred at 300 rpm for 1.5 h to obtain a uniformly mixed composite solid electrolyte material with a particle size distribution of 0.5-5 μm.

[0123] 2) Under an inert atmosphere, the composite solid electrolyte material was kept at 80°C for 1 hour, and then 2% by mass of polytetrafluoroethylene (PTFE) was added. The mixture was stirred at 800 rpm for 15 minutes to fibrose the material and obtain the fibrous composite solid electrolyte mass.

[0124] 3) The obtained fibrous composite solid electrolyte mass was subjected to multiple horizontal and vertical hot rolling processes with a roller temperature of 100℃ and a constant pressure of 2t to obtain a uniform and dense solid electrolyte membrane with a thickness of 60μm.

[0125] 2. Assembly of solid-state molded batteries:

[0126] The composite solid electrolyte membrane obtained in step 1 is placed into a solid battery mold, and a pressure of 1t is applied and held for 1 minute. Composite cathode material powder (LiNi cathode material powder raw material) is added to the cathode side. 0.8 Co 0.1 Mn 0.1 O2 (NCM811), LPSC, and conductive carbon black SP (mass ratio of the three materials 70:30:2, total thickness approximately 100 μm) were applied under a pressure of 3t for 1 min. A Li-In alloy (Li:In mass ratio 50:50, thickness approximately 50 μm) was added to the negative electrode side and a pressure of 1t was applied for 30 s. The assembled mold battery was then subjected to electrochemical testing at a constant pressure of 300 MPa (using a Blue Battery testing system).

[0127] The all-solid-state battery in this embodiment was subjected to charge-discharge tests. First, it was activated by three charge-discharge cycles at a rate of 0.1C with a cutoff voltage of 1.9V–3.7V. Then, charge-discharge cycle tests were performed at a rate of 0.3C with a cutoff voltage of 1.9V–3.7V. The test results are as follows... Figure 4 As shown.

[0128] Comparative Example 1

[0129] This comparative example provides a method for preparing a dry electrolyte membrane and a solid-state battery.

[0130] 1. Preparation method of solid electrolyte membrane:

[0131] 1) The sulfide solid electrolyte Li3PS4 (LPS) was kept at 80℃ for 1 hour. 2% by mass of polytetrafluoroethylene (PTFE) was added to the material after the insulation was heated. The mixture was stirred at 800 rpm for 15 minutes to make it fibrous, and fibrous solid electrolyte agglomerates were obtained.

[0132] 2) The obtained fibrous solid electrolyte agglomerates were subjected to multiple horizontal and vertical hot rolling processes, with the roller temperature at 100℃ and the pressure at a constant 2t, to obtain a solid electrolyte membrane with a thickness of 60μm.

[0133] 2. Assembly of solid-state molded batteries:

[0134] The solid electrolyte membrane (approximately 60 μm thick) prepared in step 1 was placed in a solid-state battery mold, and a pressure of 1 ton was applied and held for 1 minute. Composite cathode material powder (LiNi) was then added to the positive electrode side. 0.8 Co 0.1 Mn 0.1 O2 (NCM811):LPS:SP = 70:30:2, thickness approximately 100μm) was applied under a pressure of 3t for 1 min. A Li-In alloy (Li:In mass ratio 50:50, thickness approximately 50μm) was added to the negative electrode side and a pressure of 1t was applied for 30 s. The assembled mold battery was then subjected to electrochemical testing using a Blue Battery testing system under a constant pressure of 300MPa.

[0135] The solid electrolyte membrane in this comparative example was characterized by SEM, and charge-discharge tests were performed on the all-solid-state battery. First, activation was achieved by three charge-discharge cycles at a rate of 0.1C with a cutoff voltage of 1.9 V–3.7 V. Then, charge-discharge cycle tests were conducted at a rate of 0.3C with a cutoff voltage of 1.9 V–3.7 V. The test results are as follows: Figure 5 As shown.

[0136] from Figures 1-5The first-cycle charge-discharge curves of the all-solid-state batteries prepared in each embodiment and comparative example show that the first-cycle charge-discharge efficiency of Examples 1, 2, 3 and 4 can all reach more than 85%, and the charge-discharge performance is significantly better than that of the electrolyte membrane prepared by a single solid electrolyte in Comparative Example 1.

[0137] from Figure 6 It can be seen that: in Comparative Example 1(a) without the addition of a highly elastic viscous halide solid electrolyte, the porosity is most obvious in the SEM image. In Examples 1(b) and 3(c), the porosity gradually decreases as the LAOC content increases.

[0138] Electrolyte membrane tensile strength test:

[0139] The tensile strength of the electrolyte membrane was tested in a dry room at 20°C and dew point < -50°C. The tensile test was performed using a universal tensile testing machine at a speed of 100 mm / min. The thickness of the dry electrolyte membrane was 200 μm and the width was 2 cm. The tensile strength of the solid electrolyte membranes prepared in the above examples and comparative examples was tested, and the unit is MPa.

[0140] The test results are shown in Table 1:

[0141] Table 1 Tensile strength of solid electrolytes

[0142]

[0143] As can be seen from Table 1, the tensile strength of the electrolyte membrane gradually increases with the increase of the content of highly elastic viscous halide.

[0144] Finally, it should be noted that the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0145] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0146] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A novel dry-process electrolyte membrane, characterized in that, The electrolyte membrane is prepared by a dry film-forming process after combining a highly elastic and viscous halide with a solid electrolyte. The high-elasticity viscosity halide includes at least one of Li3McXb6, a derivative of Li3McXb6, Li x Md y N 1-y Cl q and a derivative of Li x Md y N 1-y Cl q . Wherein, Mc includes at least one of In, Al, Ti, Y, Dy, Gd, Ge, Sc, Zr and Yb, Md includes at least one of In, Y, Al, Zr, Sc and Ge, N includes at least one of Yb, Ti, Dy and O, Xb includes at least one of F, Cl, Br and I, 0 < x ≤ 3, 0 < q ≤ 6, 0 < y ≤ 1; The solid electrolyte includes any one of sulfide solid electrolyte, halide solid electrolyte, and oxide solid electrolyte; The mass ratio of the highly elastic viscous halide to the solid electrolyte is (1 / 9 to 9):

1.

2. The novel dry-process electrolyte membrane according to claim 1, characterized in that, The sulfide solid electrolyte includes Li6PS5Xa, derivatives of Li6PS5Xa, and Li 6+a Sb 1-a Si a S5I, Li 6+a Sb 1-a Si a S5I derivatives, Li 10 MaP2S 12 Li 10 MaP2S 12 Derivatives of Li3PS4, Li3PS4 derivatives, Li7P3S 11 Li7P3S 11 At least one of the following: derivatives of Li4MbS4 and derivatives of Li4MbS4; Wherein, Xa includes at least one of F, Cl, Br and I, Ma includes at least one of Si, Ge, Sn, Zn and Al, Mb includes any one of Si, Sn and Ge, and 0.1≤a≤0.

75.

3. The novel dry-process electrolyte membrane according to claim 1, characterized in that, The halide solid electrolyte includes Li3McXb6, derivatives of Li3McXb6, and Li x Md y N 1-y Cl q and Li x Md y N 1-y Cl q At least one of the derivatives; Wherein, Mc includes at least one of In, Al, Ti, Y, Dy, Gd, Ge, Sc, Zr and Yb, Md includes at least one of In, Y, Al, Zr, Sc and Ge, N includes at least one of Yb, Ti, Dy and O, Xb includes at least one of F, Cl, Br and I, 0 < x ≤ 3, 0 < q ≤ 6, 0 < y ≤ 1.

4. The novel dry-process electrolyte membrane according to claim 1, characterized in that, The oxide solid electrolyte includes at least one of perovskite oxide, NASICON oxide, LISICON oxide, and garnet oxide.

5. A method for preparing a novel dry-process electrolyte membrane according to any one of claims 1-4, characterized in that, The preparation method includes: The high-elasticity viscous halide and solid electrolyte are mixed evenly, and then heated and kept at a certain temperature to obtain the mixture. After adding polytetrafluoroethylene to the mixture, a fibrous treatment is performed to obtain a composite solid electrolyte group; The composite solid electrolyte clusters are rolled into a film to obtain the novel dry electrolyte membrane.

6. The method for preparing a novel dry-process electrolyte membrane according to claim 5, characterized in that, The process of mixing the high-elasticity viscous halide and the solid electrolyte evenly, followed by heating and holding at a certain temperature to obtain a mixture specifically includes: mixing the high-elasticity viscous halide and the solid electrolyte evenly by ball milling, hand milling or stirring, and then heating to 30-200°C under an inert atmosphere and holding at that temperature for 0.5-2 hours to obtain a mixture; The mass ratio of the highly elastic viscous halide to the solid electrolyte is (1 / 9 to 9):1; In the mixture, the particle size distribution of the highly elastic viscous halide and the solid electrolyte is 0.1–10 μm.

7. The method for preparing a novel dry-process electrolyte membrane according to claim 5, characterized in that, The process of adding polytetrafluoroethylene to the mixture followed by fibrosis to obtain composite solid electrolyte clusters specifically includes: After adding polytetrafluoroethylene to the mixture, mechanical stirring or manual grinding is performed to obtain composite solid electrolyte clusters; The mass of the polytetrafluoroethylene is 0.1% to 3% of the mass of the mixture; The mechanical stirring speed is 300-3000 rpm, and the stirring time is 0.1-1 h; The manual grinding time is 5 to 20 minutes.

8. The method for preparing a novel dry-process electrolyte membrane according to claim 5, characterized in that, The step of rolling the composite solid electrolyte agglomerates into a film to obtain the novel dry-process electrolyte membrane specifically includes: The composite solid electrolyte agglomerates are rolled into a film with a roller temperature of 100±10℃ and a pressure of 1.5t~3t to obtain the novel dry electrolyte membrane. The thickness of the novel dry-process electrolyte membrane is 30–300 μm; The highly elastic viscous halides include Li3McXb6, derivatives of Li3McXb6, and Li x Md y N 1-y Cl q and Li x Md y N 1-y Cl q At least one of the derivatives; Wherein, Mc includes at least one of In, Al, Ti, Y, Dy, Gd, Ge, Sc, Zr and Yb, Md includes at least one of In, Y, Al, Zr, Sc and Ge, N includes at least one of Yb, Ti, Dy and O, Xb includes at least one of F, Cl, Br and I, 0 < x ≤ 3, 0 < q ≤ 6, 0 < y ≤ 1; The solid electrolyte includes any one of sulfide solid electrolyte, halide solid electrolyte, and oxide solid electrolyte.

9. The application of a novel dry-process electrolyte membrane as described in any one of claims 1-4 in the preparation of all-solid-state batteries.

10. An all-solid-state battery, characterized in that, The all-solid-state battery contains a novel dry-process electrolyte membrane according to any one of claims 1-4.

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