Multilayer composite solid electrolyte membrane and preparation method and application thereof, and all-solid-state battery

Abstract

This invention relates to the field of solid-state lithium battery technology, and discloses a multilayer composite solid electrolyte membrane, its preparation method and application, and an all-solid-state battery. The solid electrolyte membrane sequentially comprises a sulfide electrolyte, LiX... 1 The film consists of a first binder, an oxide electrolyte, and a positive electrode component; a first stabilizing film layer; a first blended transition film layer; a sulfide electrolyte film layer containing a sulfide electrolyte, the first binder, and the oxide electrolyte; a second blended transition film layer; and a second stabilizing film layer. The first blended transition film layer, the second blended transition film layer, and the second stabilizing film layer each contain a sulfide electrolyte and LiX. 1 The first binder and oxide electrolyte; along the direction from the sulfide electrolyte film layer to the first stable film layer or the second stable film layer, LiX 1 The content of LiX in this solid electrolyte membrane shows an increasing trend. 1 The content of the electrolyte is distributed in a gradient, which significantly improves the cycle life of solid-state batteries containing this solid electrolyte membrane.

Description

Technical Field

[0001] This invention relates to the field of solid-state lithium battery technology, specifically to a multilayer composite solid electrolyte membrane, its preparation method and application, and an all-solid-state battery. Background Technology

[0002] Traditional liquid lithium-ion batteries have limited energy density and pose safety risks. Solid-state batteries, on the other hand, boast high theoretical energy density, a wide temperature range, and good safety, making them a promising energy storage technology. High-safety, high-energy-density all-solid-state batteries are an inevitable trend in technological development. In recent years, the power battery industry has experienced rapid growth, leading to an imbalance between supply and demand, accompanied by shortages of power battery materials and significant price premiums. For new energy vehicles to continue competing with traditional gasoline vehicles in the market, they must achieve comparable levels in terms of range and cost, making the development of new power battery systems urgent. Solid-state batteries, using non-flammable inorganic solid electrolytes, are considered to fundamentally solve the safety issues of new energy vehicles and have become a key development direction in the power battery field. Solid-state batteries have the following advantages:

[0003] (1) Completely eliminate the safety hazards of battery fire and explosion that are unavoidable with organic electrolytes.

[0004] (2) It is expected to be safe to use lithium metal anodes, which can achieve an energy density of over 400Wh / kg.

[0005] Therefore, developing core materials for solid-state batteries that combine high energy density and high safety, and conducting research on key interface regulation, are crucial. Selecting suitable solid-state electrolytes and high-specific-capacity positive and negative electrode materials is key to realizing high-specific-energy all-solid-state batteries. Developing solid electrolytes with high ionic conductivity, high electrochemical stability, and low cost has become one of the main research directions for developing novel all-solid-state batteries (ASSLB).

[0006] Currently, the energy density of most all-solid-state lithium batteries is far below expectations, largely due to the high thickness and weight of the electrolyte layer. Currently, it is necessary to press rigid inorganic solid electrolyte powder into sheets ranging in thickness from hundreds of micrometers to -1 mm to prevent the solid electrolyte layer from cracking. A thin solid electrolyte layer is crucial for assembling high-energy-density batteries. To achieve high energy and power densities, a layer with a thickness >10 is typically required. -4Solid-state electrolyte membranes with high ionic conductivity (micrometer scale) of S / cm are desired. However, current methods for producing such membranes present significant challenges. For example, vacuum radio frequency sputtering is prohibitively expensive, and methods such as atomic layer deposition (ALD), pulsed layer deposition (PLD), and chemical vapor deposition (CVD) are more time-consuming and have less scalability compared to roll-to-roll processes. Developing inorganic solid-state electrolyte membranes is even more challenging than developing flexible polymer electrolytes due to their poor mechanical flexibility, poor air / humidity stability, and susceptibility to chemical side reactions with polar solvents and polymer binders. To overcome these challenges, various feasible methods have been developed, including slurry coating, solution wetting, and dry film technology.

[0007] Solid-state thin-film lithium batteries, employing solid electrolyte / solid-state composite electrode films with micrometer-level thickness, offer advantages such as high safety, long lifespan, and high integration. However, the low energy density of thin-film lithium batteries is a major bottleneck limiting their widespread application, and the currently developed battery material systems are relatively limited (mostly LiCoO2 / LiPON / Li systems). If novel electrode and electrolyte materials used in traditional lithium-ion batteries could be applied to thin-film lithium batteries, it is hoped that device performance could be fundamentally improved to meet practical needs.

[0008] Ion transport and interface issues in solid-state batteries have always been a key research focus and crucial for their widespread application. The development of inorganic solid-state electrolyte membranes with excellent ion transport capabilities and high interfacial stability is essential for achieving high-energy-density all-solid-state batteries. Besides the intrinsic properties of the solid-state electrolyte membrane, the interface issues of solid-state batteries cannot be ignored. Furthermore, the electrochemical stability window of current sulfide solid electrolytes is limited, making them unsuitable for matching with positive electrode active materials and lithium metal anodes. Interface modification is still needed to achieve stable cycling at high energy density in solid-state batteries. Existing lithium metal battery solid electrolyte membranes cannot adequately balance low porosity, high compaction density, high ionic conductivity, high electrochemical stability to lithium metal, and good thermal stability. Summary of the Invention

[0009] The purpose of this invention is to address the problems of existing single-layer sulfide solid electrolyte membranes having limited electrochemical stability windows, making them unsuitable for matching with high-specific-energy electrode materials to achieve good microscopic and macroscopic contact, potential side reactions of electrolytes or electrode components, and complex preparation processes for electrode materials that match sulfide electrolytes. This invention provides a multilayer composite solid electrolyte membrane and its preparation method, as well as an all-solid-state battery. The composite solid electrolyte membrane comprises a multilayer structure of sequentially stacked membrane layers, and the solid electrolyte membrane contains LiX... 1The content of the electrolyte is distributed in a gradient, which effectively avoids the occurrence of side reactions between the solvent and the electrolyte or electrode components, improves the contact performance between the solid electrolyte membrane and the positive and negative electrodes, and significantly improves the cycle life of the solid battery containing the solid electrolyte membrane.

[0010] To achieve the above objectives, the first aspect of the present invention provides a multilayer composite solid electrolyte membrane, characterized in that the solid electrolyte membrane comprises a first stable membrane layer 1, a first mixed transition membrane layer 2, a sulfide electrolyte membrane layer 3, a second mixed transition membrane layer 4, and a second stable membrane layer 5, which are stacked sequentially.

[0011] The first stable film layer 1 includes sulfide electrolytes S-SSEs and LiX. 1 The mixture, first binder, oxide electrolyte and positive electrode component;

[0012] The first mixed transition film layer 2, the second mixed transition film layer 4, and the second stable film layer 5 each independently include sulfide electrolytes S-SSEs and LiX. 1 The admixture, the first binder, and the oxide electrolyte;

[0013] The sulfide electrolyte membrane 3 includes sulfide electrolytes S-SSEs, a first binder, and an oxide electrolyte;

[0014] Among them, X 1 It is a halogen, preferably, X 1 For F;

[0015] Along the direction from the sulfide electrolyte membrane layer 3 to the first stable membrane layer 1, LiX 1 The content of [ ] shows an increasing trend;

[0016] Along the direction from the sulfide electrolyte membrane layer 3 to the second stable membrane layer 5, LiX 1 The content of [something] shows an increasing trend.

[0017] A second aspect of the present invention provides a method for preparing a multilayer composite solid electrolyte membrane, characterized in that the preparation method includes the following steps:

[0018] S1, positive electrode components, sulfide electrolyte S-SSEs, LiX 1 The first binder and oxide electrolyte are mixed to obtain the first stable film precursor 1;

[0019] S2, sulfide electrolytes S-SSEs, LiX 1 The first binder and oxide electrolyte are mixed to obtain the first mixed transition film precursor 2;

[0020] S3. The sulfide electrolyte S-SSEs, the first binder and the oxide electrolyte are mixed to obtain the sulfide electrolyte membrane precursor 3.

[0021] S4, sulfide electrolytes S-SSEs, LiX 1 The first binder and oxide electrolyte are mixed to obtain the second mixed transition film precursor 4;

[0022] S5, sulfide electrolytes S-SSEs, LiX 1 The first binder and oxide electrolyte are mixed to obtain the second stable membrane precursor 5;

[0023] Among them, X 1 It is a halogen, preferably, X 1 For F;

[0024] S6. The first stabilizing membrane precursor 1, the first mixed transition membrane precursor 2, the sulfide electrolyte 3, the second mixed transition membrane precursor 4, and the second stabilizing membrane precursor 5 are sequentially combined to obtain a multilayer composite solid electrolyte membrane.

[0025] Among them, LiX in each step 1 The dosage is such that, along the direction from the sulfide electrolyte membrane layer 3 to the first stable membrane layer 1, LiX 1 The content of LiX shows an increasing trend; along the direction from the sulfide electrolyte membrane layer 3 to the second stable membrane layer 5, the content of LiX increases. 1 The content of [something] shows an increasing trend.

[0026] A third aspect of the present invention provides a multilayer composite solid electrolyte membrane prepared by the above-described preparation method.

[0027] A fourth aspect of the present invention provides an all-solid-state battery, characterized in that the all-solid-state battery includes a positive electrode, a negative electrode and the above-mentioned multilayer composite solid electrolyte membrane, wherein the current collector of the positive electrode is located on one side of the first stabilizing membrane layer 1, and the negative electrode is located on one side of the second stabilizing membrane layer 5.

[0028] Through the above technical solutions, the multilayer composite solid electrolyte membrane, its preparation method and application, and solid-state batteries provided by the present invention achieve the following beneficial effects:

[0029] The multilayer composite solid electrolyte membrane provided by this invention comprises a multilayer membrane structure stacked sequentially, wherein each membrane layer independently contains a sulfide electrolyte and optionally LiX. 1 Furthermore, the compound LiX in each film layer structure 1 The content of LiX exhibits a gradient distribution; specifically, along the direction from the center to the surface of the multilayer composite solid electrolyte membrane, the content of LiX... 1The content of halogens increases gradually, resulting in a uniformly progressive halogen chemical environment in the multilayer composite solid electrolyte membrane; due to the compound LiX 1 The interface passivation characteristics of LiX with uniform gradient distribution 1 It can effectively avoid side reactions between solvent and electrolyte or electrode components, and can stably match high energy density electrodes for charge-discharge cycles.

[0030] Furthermore, in the multilayer composite solid electrolyte membrane provided by this invention, the average particle size of the sulfide electrolytes S-SSEs in each membrane layer structure exhibits a gradient change. Specifically, along the direction from the center to the surface of the multilayer composite solid electrolyte membrane, the average particle size of the sulfide electrolytes S-SSEs gradually decreases. The sulfide electrolytes S-SSEs are uniformly distributed in the multilayer composite solid electrolyte membrane, and the particle contact at the interface of each membrane layer is good, which can realize the mixing of LiX-containing components in the transition membrane layer and the stabilizing layer. 1 The uniform dispersion of the component sulfide electrolyte S-SSEs significantly increases the effective contact sites between the multilayer composite solid electrolyte membrane and the positive and negative electrode materials, thereby fully leveraging the interface protection and passivation effects brought about by the uniformly progressive halogen chemical environment.

[0031] The multilayer composite solid electrolyte membrane provided by this invention adopts the sulfide solid electrolyte system with high ionic conductivity. Through the design of different membrane layer chemical compositions and physical particle size distribution, it achieves high electrochemical stability for high specific energy positive oxide and negative electrode metallic lithium, thereby effectively improving the cycle life of all-solid-state lithium batteries. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the multilayer composite solid electrolyte membrane of the present invention;

[0033] Figure 2 This is a schematic diagram of the electrochemical cycling performance of the solid-state batteries assembled with multilayer composite solid electrolyte membranes in Example 1 and Comparative Example 1.

[0034] Explanation of reference numerals in the attached figures

[0035] 1-First stable film layer; 2-First blended transition film layer; 3-Sulfide electrolyte film layer; 4-Second blended transition film layer; 5-Second stable film layer. Detailed Implementation

[0036] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0037] The first aspect of the present invention provides a multilayer composite solid electrolyte membrane, characterized in that the solid electrolyte membrane comprises a first stable membrane layer 1, a first mixed transition membrane layer 2, a sulfide electrolyte membrane layer 3, a second mixed transition membrane layer 4, and a second stable membrane layer 5, which are stacked sequentially.

[0038] The first stable film layer 1 includes sulfide electrolytes S-SSEs and LiX. 1 The mixture, first binder, oxide electrolyte and positive electrode component;

[0039] The first mixed transition film layer 2, the second mixed transition film layer 4, and the second stable film layer 5 each independently include sulfide electrolytes S-SSEs and LiX. 1 The admixture, the first binder, and the oxide electrolyte;

[0040] The sulfide electrolyte membrane 3 includes sulfide electrolytes S-SSEs, a first binder, and an oxide electrolyte;

[0041] Among them, X 1 It is a halogen, preferably, X 1 For F;

[0042] Along the direction from the sulfide electrolyte membrane layer 3 to the first stable membrane layer 1, LiX 1 The content of [ ] shows an increasing trend;

[0043] Along the direction from the sulfide electrolyte membrane layer 3 to the second stable membrane layer 5, LiX 1 The content of [something] shows an increasing trend.

[0044] In this invention, the multilayer composite solid electrolyte membrane comprises a multilayer membrane structure stacked sequentially, and each membrane layer independently contains a sulfide electrolyte and optionally LiX. 1 Furthermore, the compound LiX in each film layer structure 1 The content of LiX exhibits a gradient distribution; specifically, along the direction from the center to the surface of the multilayer composite solid electrolyte membrane, the content of LiX... 1 The content of halogens increases, resulting in a uniformly progressive halogen chemical environment in the multilayer composite solid electrolyte membrane; due to the increasing content of LiX... 1 The halogen atoms in LiX have high electronegativity and strong ionic bond energy, making them difficult to redox decompose, thus making LiX... 1 It exhibits interface passivation properties. Gradient-distributed LiX 1 It can effectively avoid side reactions between solvent and electrolyte or electrode components, which is beneficial to protect the inner solid electrolyte from oxidation and degradation, and can stably match high energy density electrodes for charge and discharge cycles.

[0045] In this invention, to further improve the lithium-ion transport rate and membrane interface stability of the solid electrolyte membrane, preferably, X 1 It is F.

[0046] According to the present invention, the sulfurized electrolytes S-SSEs are selected from compounds of formula I, Li 4-x Ge 1-x P x S4 (thio-LISICON), Li 10 GeP2S 12 Li 10 SnP2S 12 At least one of Li2S-P2S5, Li2S-SiS2, Li2S-B2S3, LiSiPSCl, LiSiPSBr and LiSiPSI, wherein 0≤x≤2;

[0047] Li 6-a PS 5-a Cl 1+a-b X 2 b Formula I;

[0048] Among them, X 2 It is at least one of Cl, Br or I, preferably X 2 It is at least one of Cl or Br, 0≤a≤3, 0≤b≤3.

[0049] According to the present invention, based on the total molar amount of the admixtures in the first stable film layer 1, LiX 1 The molar content is 20 mol%-40 mol%.

[0050] Based on the total molar amount of the dopant in the first mixed transition film layer 2, LiX 1 The molar content is 0.5 mol%-20 mol%.

[0051] In this invention, the LiX content in the first stable film layer 1 and the first mixed transition film layer 2 is controlled. 1 When the molar content meets the above range, the side reactions between the oxide cathode material and the sulfide electrolyte material components can be effectively avoided, which significantly improves the cycle life of the solid-state battery containing the solid electrolyte membrane.

[0052] Furthermore, based on the total molar amount of the admixtures in the first stable film layer 1, LiX 1 The molar content is 30 mol%-35 mol%.

[0053] Based on the total molar amount of the dopant in the first mixed transition film layer 2, LiX1 The molar content is 10 mol%-15 mol%.

[0054] According to the present invention, based on the total molar amount of the admixtures in the second mixed transition film layer 4, LiX 1 The molar content is 0.5 mol%-20 mol%.

[0055] Based on the total molar amount of the dopants in the second stable film layer 5, LiX 1 The molar content is 20 mol%-40 mol%.

[0056] In this invention, the LiX content in the second mixed transition film layer 4 and the second stable film layer 5 is controlled. 1 When the molar content meets the above range, the side reactions between the lithium metal anode material and the sulfide electrolyte material components can be effectively avoided.

[0057] Furthermore, based on the total molar amount of the dopant in the second mixed transition film layer 4, LiX 1 The molar content is 10 mol%-15 mol%.

[0058] Based on the total molar amount of the dopants in the second stable film layer 5, LiX 1 The molar content is 30 mol%-35 mol%.

[0059] According to the present invention, the average particle size of the sulfide electrolytes S-SSEs decreases along the direction from the sulfide electrolyte membrane layer 3 to the first stable membrane layer 1.

[0060] Along the direction from the sulfide electrolyte membrane layer 3 to the second stable membrane layer 5, the average particle size of the sulfide electrolyte S-SSEs decreases.

[0061] In this invention, the average particle size of sulfide electrolytes S-SSEs in each layer of the multilayer composite solid electrolyte membrane exhibits a gradient change. Specifically, along the direction from the center to the surface of the multilayer composite solid electrolyte membrane, the average particle size of sulfide electrolytes S-SSEs gradually decreases. The sulfide electrolytes S-SSEs are uniformly distributed in the multilayer composite solid electrolyte membrane, and the particles at the interfaces of each membrane layer have good contact, enabling the mixing of LiX1-containing components in the transition membrane layer and the stabilizing layer. 1The uniform dispersion of the component sulfide electrolytes S-SSEs significantly increases the effective contact sites between the multilayer composite solid electrolyte membrane and the positive and negative electrode materials, thereby fully leveraging the interface protection and passivation effects brought about by the uniformly progressive halogen chemical environment. Specifically, in this invention, the sulfide electrolytes S-SSEs in the sulfide electrolyte membrane layer 3 are micron-sized particles, the sulfide electrolytes S-SSEs in the first blended transition membrane layer 2 and the second blended transition membrane layer 4 are each independently submicron-sized particles, and the sulfide electrolytes S-SSEs in the first stable membrane layer 1 and the second stable membrane layer 5 are each independently nano-sized particles.

[0062] According to the present invention, the average particle size of the sulfide electrolytes S-SSEs in the first stable film layer 1 is 50-400 nm.

[0063] According to the present invention, the average particle size of the sulfide electrolytes S-SSEs in the first mixed transition film layer 2 is 0.4-1 μm.

[0064] According to the present invention, the average particle size of the sulfide electrolytes S-SSEs in the sulfide electrolyte membrane layer 3 is 1-10 μm.

[0065] According to the present invention, the average particle size of the sulfide electrolytes S-SSEs in the second blended transition film layer 4 is 0.4-1 μm.

[0066] According to the present invention, the average particle size of the sulfide electrolytes S-SSEs in the second stable film layer 5 is 50-400 nm.

[0067] In this invention, when the average particle size of the sulfide electrolytes S-SSEs in each membrane layer meets the above-mentioned range, the effective contact sites between the multilayer composite solid electrolyte membrane and the positive and negative electrode materials are significantly increased, thereby giving full play to the interface protection and passivation effect brought about by the uniformly progressive halogen chemical environment.

[0068] In this invention, sulfide electrolytes S-SSEs with different average particle sizes are obtained by crushing. Specifically, crushing equipment such as crushers, stirred mills, sand mills, and air jet mills are used to crush them to the target particle size range.

[0069] Furthermore, the average particle size of the sulfide electrolytes S-SSEs in the first stable film layer 1 is 200-400 nm.

[0070] Furthermore, the average particle size of the sulfide electrolytes S-SSEs in the first mixed transition film layer 2 is 0.4-0.8 μm.

[0071] Furthermore, the average particle size of the sulfide electrolytes S-SSEs in the sulfide electrolyte membrane layer 3 is 1-3 μm.

[0072] Furthermore, the average particle size of the sulfide electrolytes S-SSEs in the second blended transition film layer 4 is 0.4-0.8 μm.

[0073] Furthermore, the average particle size of the sulfide electrolytes S-SSEs in the second stable film layer 5 is 200-400 nm.

[0074] According to the present invention, the thickness of the multilayer composite solid electrolyte membrane is 10-500 μm, preferably 10-100 μm, and more preferably 6-15 μm.

[0075] According to the present invention, the thickness of the first stabilizing film 1 is 0.5-1 μm, preferably 0.6-0.9 μm, and more preferably 0.7-0.8 μm.

[0076] According to the present invention, the thickness of the first mixed transition film layer 2 is 0.5-1 μm, preferably 0.6-0.9 μm, and more preferably 0.7-0.8 μm.

[0077] According to the present invention, the thickness of the sulfide electrolyte membrane layer 3 is 4-11 μm, preferably 6-9 μm, and more preferably 7-8 μm.

[0078] According to the present invention, the thickness of the second mixed transition film layer 4 is 0.5-1 μm, preferably 0.6-0.9 μm, and more preferably 0.7-0.8 μm.

[0079] According to the present invention, the thickness of the second stabilizing film layer 5 is 0.5-1 μm, preferably 0.6-0.9 μm, and more preferably 0.7-0.8 μm.

[0080] According to the present invention, the first stable film layer 1 comprises 9.4-39.76 parts by weight of an admixture, 0.05-2 parts by weight of a first binder, 0.01-0.4 parts by weight of an oxide electrolyte and 60-90 parts by weight of a positive electrode component.

[0081] In this invention, when the content of each component in the first stabilizing film 1 is controlled to meet the above-mentioned range, the positive electrode material and the electrolyte material can be fully and uniformly mixed, so that the first stabilizing film can achieve good lithium-ion conduction performance.

[0082] Further, the first stabilizing film layer 1 comprises 18.8-29.82 parts by weight of a blend, 0.1-1.5 parts by weight of a first binder, 0.02-0.3 parts by weight of an oxide electrolyte, and 70-80 parts by weight of a positive electrode material.

[0083] According to the present invention, the first blended transition film layer 2 comprises 94-99.4 parts by weight of the blend, 0.5-5 parts by weight of the binder and 0.1-1 parts by weight of the oxide electrolyte.

[0084] According to the present invention, the sulfide electrolyte membrane layer 3 comprises 94-99.4 parts by weight of sulfide electrolytes S-SSEs, 0.5-5 parts by weight of binder and 0.1-1 parts by weight of oxide electrolyte.

[0085] According to the present invention, the second blended transition film layer 4 comprises 94-99.4 parts by weight of the blend, 0.5-5 parts by weight of the binder and 0.1-1 parts by weight of the oxide electrolyte.

[0086] According to the present invention, the second stable film layer 5 comprises 94-99.4 parts by weight of an admixture, 0.5-5 parts by weight of a binder, and 0.1-1 parts by weight of an oxide electrolyte.

[0087] In this invention, when the compositions of the first blended transition film layer 2, the sulfide electrolyte film layer 3, the second blended transition film layer 4, and the second stable film layer 5 are each independently controlled to meet the above-mentioned range, the occurrence of side reactions between the oxide cathode material and the sulfide electrolyte material components can be effectively avoided. The introduction of the first binder is beneficial to the subsequent film formation process of the material, and the introduction of the oxide electrolyte, as a high-hardness inorganic solid electrolyte, is beneficial to the fibrous film formation.

[0088] In this invention, a certain amount of oxide electrolyte is added to the first stable film layer 1, the first mixed transition film layer 2, the sulfide electrolyte film layer 3, the second mixed transition film layer 4, and the second stable film layer 5 to ensure that each film layer has sufficient strength to meet the requirements of subsequent processing.

[0089] Furthermore, the first blended transition film layer 2 includes 96-99 parts by weight of the blend, 0.5-2 parts by weight of the binder, and 0.5-1 parts by weight of the oxide electrolyte.

[0090] Furthermore, the sulfide electrolyte membrane layer 3 comprises 96-99 parts by weight of sulfide electrolytes S-SSEs, 0.5-2 parts by weight of binder, and 0.5-1 parts by weight of oxide electrolyte.

[0091] Furthermore, the sulfide electrolyte membrane layer 4 comprises 96-99 parts by weight of an admixture, 0.5-2 parts by weight of a binder, and 0.5-1 parts by weight of an oxide electrolyte.

[0092] Furthermore, the second stable film layer 5 includes 96-99 parts by weight of an admixture, 0.5-2 parts by weight of a binder, and 0.5-1 parts by weight of an oxide electrolyte.

[0093] According to the present invention, the first adhesive is at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), (vinylidene fluoride-hexafluoropropylene) copolymer (PVDF-HFP), polyethylene oxide (PEO), polyacrylonitrile (PAN), and styrene-butadiene rubber (SBR).

[0094] According to the present invention, the average particle size of the first adhesive is 10-1000 μm.

[0095] According to the present invention, the number average molecular weight of the first adhesive is greater than or equal to 100,000 g / mol, and the compression ratio is 1-10000:1.

[0096] In this invention, when the average particle size and / or number-average molecular weight and compression ratio of the first binder are controlled to meet the above range, the first binder can be more easily fiberized under shear force, and the diameter and mechanical strength of the fibers obtained after the first binder is fiberized are more likely to meet the requirements of ultra-thin electrolyte membranes, and the prepared electrolyte membrane is thinner and more resilient.

[0097] Furthermore, according to the present invention, the average particle size of the first adhesive is 300-600 μm.

[0098] Furthermore, the number-average molecular weight of the first adhesive is greater than or equal to 3,000,000 g / mol, and the compression ratio is 3,000-5,000:1.

[0099] According to the present invention, the oxide electrolyte is selected from at least one of lithium lanthanum zirconium oxide (LLZO), lithium lanthanum zirconium tantalum oxide (LLZTO), lithium titanium aluminum phosphate (LATP), and lithium germanium aluminum phosphate (LAGP); preferably selected from lithium lanthanum zirconium oxide (LLZO) and / or lithium lanthanum zirconium tantalum oxide (LLZTO) with a garnet structure.

[0100] In this invention, there is no particular limitation on the composition of the positive electrode component, and conventional positive electrode components in the art can be used. Preferably, the positive electrode component includes a positive electrode active material, a conductive agent, a lithium salt, and a second binder.

[0101] The mass ratio of the positive electrode active material, the conductive agent, the lithium salt, and the second binder is 65-98:0.5-10:0.5-10:1-15.

[0102] Furthermore, the mass ratio of the positive electrode active material, the conductive agent, the lithium salt, and the second binder is 70-92:1-5:1-5:2-10.

[0103] In this invention, there is no particular limitation on the type of positive electrode active material; conventional positive electrode active materials in the art can be used. Specifically, the positive electrode active material is a multi-element positive electrode material, such as lithium cobalt oxide (LiCoO2, LCO), lithium manganese oxide (LiMnO2), and lithium nickel manganese oxide (LiNiO2). 1-α Mn α O2, 0<α<1, lithium nickel cobalt manganese oxide (LiNi β Co γ Mn δ O2, β+γ+δ=1, β, γ and δ are all greater than 0) and lithium nickel cobalt aluminum oxide (LiNiκCo) λ Al μ At least one of the following: O2, κ+λ+μ=1, where κ, λ, and μ are all greater than 0; the positive electrode active material is an olivine positive electrode material, for example, selected from at least one of lithium iron phosphate (LiFePO4), lithium manganese iron phosphate (LiFeMnPO4), and lithium manganese phosphate (LiMnPO4); the positive electrode active material is a lithium-rich manganese-based material [σLi2MnO3·(1-σ)LiNi ω Co γ Mn δ O2, 0<σ<1, ω+γ+δ=1, ω, γ and δ are all greater than 0].

[0104] In this invention, there is no particular limitation on the type of conductive agent. Conventional conductive agents in the art can be used, such as at least one selected from Super P, acetylene black, graphite, KS-6, carbon nanotubes, graphene and carbon fiber.

[0105] In this invention, there is no particular limitation on the type of lithium salt, and conventional lithium salts in the art can be used, such as at least one selected from lithium perchlorate (LiClO4), lithium tetrafluoroborate (LiBF4), lithium hexafluoroarsenate (LiAsF6), lithium hexafluorophosphate (LiPF6), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(oxalateborate)borate (LiBOB), and lithium di(fluorooxalateborate)borate (LiDFOB).

[0106] In this invention, there is no particular limitation on the type of the second adhesive; conventional adhesives in the art can be used. For example, the second adhesive is selected from small molecule organic compounds and / or polymers. In this invention, there is no particular limitation on the type of polymer; conventional polymer adhesives in the art can be used, such as at least one selected from polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), (vinylidene fluoride-hexafluoropropylene) copolymer (PVDF-HFP), polyethylene oxide (PEO), polydimethylsiloxane (PDMS), polymethyl methacrylate (PMMA), polyacrylonitrile (PAN), polypropylene carbonate (PPC), ethylene carbonate (PEC), polycaprolactone (PCL), and styrene-butadiene rubber (SBR).

[0107] In this invention, there is no particular limitation on the type of small molecule organic compound. Conventional small molecule organic compounds that can be used as binders in the art can be used, such as those selected from acrylate compounds and / or vinyl ester compounds, preferably at least one of polyethylene glycol dimethyl ether (PEGDME), triethylene glycol dimethyl ether (TEGDME), polyethylene glycol diacrylate (PEGDA), polyethylene glycol dimethacrylate (PEGDMA), triethylene glycol dimethacrylate (TEGDMA), and trimethylolpropane triacrylate (TMPTA).

[0108] In this invention, when a small molecule organic compound is used as the second binder, the binder further includes an initiator. Based on the amount of the second binder, the amount of the initiator is 0.1 wt%-5 wt%, preferably 0.5 wt%-2 wt%. In this invention, the initiator is selected from azo initiators and / or peroxide initiators, preferably at least one selected from azobisisobutyronitrile, azobisisoheptanenitrile and dimethyl azobisisobutyrate, benzoyl peroxide, tert-butyl peroxide, and methyl ethyl ketone peroxide.

[0109] In one specific embodiment of the present invention, the mass ratio of the small molecule organic compound to the high molecular weight polymer is 0:100-100:0, and the two are not both 0.

[0110] In a preferred embodiment of the present invention, the mass ratio of the small molecule organic compound to the high molecular polymer is 20-80:80-20.

[0111] According to the present invention, the porosity of the multilayer composite solid electrolyte membrane is 1%-20%.

[0112] In this invention, the multilayer composite solid electrolyte membrane has the aforementioned specific porosity, which makes the multilayer composite solid electrolyte membrane and the solid lithium battery made from the membrane have superior performance.

[0113] Furthermore, the porosity of the multilayer composite solid electrolyte membrane is 7%-10%.

[0114] According to the present invention, the compaction density of the multilayer composite solid electrolyte membrane is 2 g / cm³. 3 6g / cm 3 .

[0115] In this invention, the multilayer composite solid electrolyte membrane has the aforementioned specific compaction density, which makes the multilayer composite solid electrolyte membrane and the solid lithium battery made from the membrane have superior performance.

[0116] Furthermore, the compaction density of the multilayer composite solid electrolyte membrane is 3 g / cm³. 3 5.5g / cm 3 .

[0117] According to the present invention, the peel strength of the multilayer composite solid electrolyte membrane is 300-800 N / m.

[0118] In this invention, the multilayer composite solid electrolyte membrane has the aforementioned specific peel strength, which makes the multilayer composite solid electrolyte membrane and the solid lithium battery made from the membrane have superior performance.

[0119] Furthermore, the peel strength of the multilayer composite solid electrolyte membrane is 400-700 N / m.

[0120] According to the present invention, the ionic conductivity of the multilayer composite solid electrolyte membrane is ≥10. -4 S / cm, preferably 5×10 -4 S / cm-5×10 -3 S / cm.

[0121] A second aspect of the present invention provides a method for preparing a multilayer composite solid electrolyte membrane, characterized in that the preparation method includes the following steps:

[0122] S1, positive electrode components, sulfide electrolyte S-SSEs, LiX 1 The first binder and oxide electrolyte are mixed to obtain the first stable film precursor 1;

[0123] S2, sulfide electrolytes S-SSEs, LiX 1 The first binder and oxide electrolyte are mixed to obtain the first mixed transition film precursor 2;

[0124] S3. The sulfide electrolyte S-SSEs, the first binder and the oxide electrolyte are mixed to obtain the sulfide electrolyte membrane precursor 3.

[0125] S4, sulfide electrolytes S-SSEs, LiX 1 The first binder and oxide electrolyte are mixed to obtain the second mixed transition film precursor 4;

[0126] S5, sulfide electrolytes S-SSEs, LiX 1 The first binder and oxide electrolyte are mixed to obtain the second stable membrane precursor 5;

[0127] Among them, X 1 It is a halogen, preferably, X 1 For F;

[0128] S6. The first stabilizing membrane precursor 1, the first mixed transition membrane precursor 2, the sulfide electrolyte 3, the second mixed transition membrane precursor 4, and the second stabilizing membrane precursor 5 are sequentially combined to obtain a multilayer composite solid electrolyte membrane.

[0129] Among them, LiX in each step 1 The dosage is such that, along the direction from the sulfide electrolyte membrane layer 3 to the first stable membrane layer 1, LiX 1 The content of LiX shows an increasing trend; along the direction from the sulfide electrolyte membrane layer 3 to the second stable membrane layer 5, the content of LiX increases. 1 The content of [something] shows an increasing trend.

[0130] The raw material composition and specific types used in the preparation of the multilayer composite solid electrolyte membrane in the second aspect of this invention are exactly the same as those used in the multilayer composite solid electrolyte membrane described in the first aspect of this invention. To avoid repetition, this invention will not repeat the details in this second aspect, and those skilled in the art should not understand it as a limitation of this invention.

[0131] In this invention, different film layers are prepared by distribution and then sequentially composited in a specific order to obtain the LiX described in the first aspect of this invention. 1 The content of the solid electrolyte membrane is distributed in a gradient in the multilayer composite solid electrolyte membrane.

[0132] In one specific embodiment of the present invention, in step S6, the composite method includes: sequentially coating and drying the first stabilizing membrane precursor 1, the first blended transition membrane precursor 2, the sulfide electrolyte 3, the second blended transition membrane precursor 4, and the second stabilizing membrane precursor 5.

[0133] In this invention, when lamination is performed using a coating method, the method further includes:

[0134] (1) Sulfide electrolytes S-SSEs and LiX 1The first binder, oxide electrolyte and positive electrode components are dispersed in an organic solvent to obtain a slurry. The slurry is coated on a base film, dried and the base film is peeled off to obtain the first stable film precursor 1.

[0135] (2) Sulfide electrolytes S-SSEs and LiX 1 The first binder and oxide electrolyte are dispersed in an organic solvent to obtain a slurry. The slurry is coated on a base film, dried, and the base film is peeled off to obtain the first mixed transition film precursor 2.

[0136] (3) The sulfide electrolyte S-SSEs, the first binder and the oxide electrolyte are dispersed in an organic solvent to obtain a slurry. The slurry is coated on the base film, dried and the base film is peeled off to obtain the sulfide electrolyte membrane precursor 3.

[0137] (4) Sulfide electrolytes S-SSEs and LiX 1 The first binder and oxide electrolyte are dispersed in an organic solvent to obtain a slurry. The slurry is coated on a base film, dried, and the base film is peeled off to obtain the second blended transition film precursor 4.

[0138] (5) Sulfide electrolytes S-SSEs and LiX 1 The first binder and oxide electrolyte are dispersed in an organic solvent to obtain a slurry. The slurry is coated on a base film, dried, and the base film is peeled off to obtain the second stable film precursor 5.

[0139] (6) The first stabilizing membrane precursor 1, the first blended transition membrane precursor 2, the sulfide electrolyte 3, the second blended transition membrane precursor 4, and the second stabilizing membrane precursor 5 are sequentially stacked, pressed into sheets, and co-extruded to obtain a multilayer composite solid electrolyte membrane.

[0140] In this invention, there is no particular limitation on the coating method; conventional coating methods in the art, such as scraping, can be used.

[0141] In this invention, there is no particular limitation on the type of organic solvent, and conventional organic solvents in the art, such as toluene, can be used.

[0142] According to the present invention, the drying conditions in each step include: drying temperature of 60-200℃ and drying time of 0.5-5h.

[0143] In another specific embodiment of the present invention, in step S6, the composite method includes: sequentially stacking the first stabilizing membrane precursor 1, the first blended transition membrane precursor 2, the sulfide electrolyte 3, the second blended transition membrane precursor 4, and the second stabilizing membrane precursor 5, and then performing co-extrusion.

[0144] In this invention, when compounding is performed by co-extrusion, the method further includes:

[0145] (i) The positive electrode components, oxide electrolyte, first binder, sulfide electrolyte S-SSEs and LiX are combined. 1 Mix and compress to obtain the first stable film precursor 1;

[0146] (ii) Sulfide electrolytes S-SSEs, LiX 1 The first binder and oxide electrolyte are mixed and compressed into tablets to obtain the first mixed transition membrane precursor 2;

[0147] (iii) The sulfide electrolyte S-SSEs, the first binder and the oxide electrolyte are mixed and pressed into tablets to obtain sulfide electrolyte membrane precursor 3;

[0148] (iv) Sulfide electrolytes S-SSEs, LiX 1 The first binder and oxide electrolyte are mixed and compressed into tablets to obtain the second blended transition membrane precursor 4;

[0149] (v) Sulfide electrolytes S-SSEs, LiX 1 The first binder and oxide electrolyte are mixed and compressed into tablets to obtain the second stable membrane precursor 5;

[0150] (vi) The first stabilizing membrane precursor 1, the first blended transition membrane precursor 2, the sulfide electrolyte 3, the second blended transition membrane precursor 4, and the second stabilizing membrane precursor 5 are sequentially stacked, pressed into sheets, and co-extruded to obtain a multilayer composite solid electrolyte membrane.

[0151] According to the present invention, the co-extrusion is integral hot pressing, and the hot pressing temperature is 40-100℃.

[0152] In this invention, there are no particular limitations on the mixing method. Conventional equipment in the art can be used for mixing, such as grinding mills, ball mills, air jet mills, or screw extruders.

[0153] In this invention, there is no particular limitation on the overall hot pressing method. Conventional equipment in the art can be used for overall hot pressing, such as hot rollers, hot press plates, etc.

[0154] A third aspect of the present invention provides a multilayer composite solid electrolyte membrane prepared by the above-described preparation method.

[0155] The fourth aspect of the present invention provides an application of the above-mentioned multilayer composite solid electrolyte membrane in a solid-state battery.

[0156] In this invention, when the multilayer composite solid electrolyte membrane is used in an all-solid-state battery, the prepared multilayer composite solid electrolyte membrane is thin, and the extremely low content of binder ensures sufficient contact between inorganic electrolyte particles, avoiding the influence of binder on the lithium-ion conductivity of the electrolyte. The prepared membrane has high ionic conductivity and a wide electrochemical window, enabling the all-solid-state battery to achieve better cycle stability.

[0157] In this invention, after assembling the multilayer composite solid electrolyte membrane with a lithium metal electrode into a CNT / / solid electrolyte membrane / / Li mold battery, a linear voltammetric scan is performed. The positive scan peak potential of the multilayer composite solid electrolyte membrane is ≥4V; the integral current area is ≤5×10 -3 AV / cm 2 Cut-off current density ≤ 0.01 A / cm² 2 For lithium metal, the peak potential is ≤0.5V; the integral current area is ≤1×10⁻⁶. -3 AV / cm 2 Cut-off current density ≤ 0.01 A / cm² 2 .

[0158] In this invention, the multilayer composite solid electrolyte membrane is assembled into a lithium-symmetric battery. Battery cycle life and critical current density are tested. The battery cycle stability time is ≥800 hours, the cycle stability lithium insertion / extraction polarization potential is ≤1V, and the critical current density is 0.1-1 mA / cm². 2 .

[0159] The fifth aspect of the present invention provides an all-solid-state battery, characterized in that the solid-state battery includes a positive electrode, a negative electrode and the above-mentioned multilayer composite solid electrolyte membrane, wherein the current collector of the positive electrode is located on one side of the first stabilizing membrane layer 1, and the negative electrode is located on one side of the second stabilizing membrane layer 5.

[0160] In this invention, the current collector is aluminum foil, preferably mesh aluminum foil and / or carbon-coated aluminum foil.

[0161] In this invention, the negative electrode is preferably a lithium-containing negative electrode.

[0162] The present invention will be described in detail below through embodiments.

[0163] Example 1

[0164] This embodiment provides a method for preparing a multilayer composite co-extruded solid electrolyte membrane that matches a high specific energy electrode:

[0165] (i) 80 parts by weight of the positive electrode component, 19 parts by weight of the mixture of 30LiF·70Li6PS5Cl (D50 = 500 nm), 0.5 parts by weight of the first binder PTFE (molecular weight 1,000,000 g / mol, D50 = 100 μm, compression ratio 100:1), and 0.5 parts by weight of LLZTO (D50 = 1 μm) were placed in a mortar and mixed until a dough-like mixture was formed. The mixture was then placed between stainless steel plates and flattened to obtain the first stable film precursor 1. The mass ratio of the positive electrode active material (LCO), conductive agent acetylene black, lithium salt LiFSI, and binder polyethylene oxide in the positive electrode component was 83:5:3:9.

[0166] (ii) 99 parts by weight of 10LiF·90Li6PS5Cl (D50 = 1 μm), 0.5 parts by weight of LLZTO (D50 = 1 μm), and 0.5 parts by weight of PTFE (molecular weight 1,000,000 g / mol, D50 = 100 μm, compression ratio 100:1) were placed in a mortar and mixed until a dough-like mixture was formed. Then the mixture was placed between stainless steel plates and flattened to obtain the first blended transition film precursor 2.

[0167] (iii) 99 parts by weight of Li6PS5Cl (D50 = 5 μm), 0.5 parts by weight of LLZTO (D50 = 1 μm) and 0.5 parts by weight of PTFE (molecular weight 1,000,000 g / mol, D50 = 100 μm, compression ratio 100:1) were placed in a mortar and mixed until a dough-like mixture was formed. Then the mixture was placed between stainless steel plates and flattened to obtain sulfide electrolyte membrane precursor 3.

[0168] (iv) 99 parts by weight of 10LiF·90Li6PS5Cl (D50 = 1 μm), 0.5 parts by weight of LLZTO (D50 = 1 μm), and 0.5 parts by weight of PTFE (molecular weight 1,000,000 g / mol, D50 = 100 μm, compression ratio 100:1) were placed in a mortar and mixed until a dough-like mixture was formed. Then, the mixture was placed between stainless steel plates and flattened to obtain the second blended transition film precursor 4.

[0169] (v) 99 parts by weight of 30LiF·70Li6PS5Cl (D50 = 500 nm), 0.5 parts by weight of LLZTO (D50 = 1 μm), and 0.5 parts by weight of PTFE (molecular weight 1,000,000 g / mol, D50 = 100 μm, compression ratio 100:1) were placed in a mortar and mixed until a dough-like mixture was formed. The mixture was then placed between stainless steel plates and flattened to obtain the second stable film precursor 5.

[0170] (vi) as Figure 1 As shown, the first stabilizing membrane precursor 1, the first blended transition membrane precursor 2, the sulfide electrolyte precursor 3, the second blended transition membrane precursor 4, and the second stabilizing membrane precursor 5 are stacked in the order of 1-2-3-4-5 and initially flattened. They are then repeatedly co-extruded and compounded using a hot roller press at a temperature of 120°C to obtain a multilayer composite co-extruded solid electrolyte film A1 with a thickness of 30 μm.

[0171] The cycling performance of the multilayer composite solid electrolyte membrane A1 obtained above was determined for solid-state lithium metal batteries:

[0172] With LiCoO2 as the positive electrode, the loading was 36 mg / cm³. 2 Using lithium metal as the negative electrode, charge and discharge tests were conducted with a test voltage range of 2.6-4.3V.

[0173] Using LiCoO2 cathode material 36mg / cm 2 A battery is assembled using the aforementioned multilayer composite solid electrolyte membrane A1 and lithium sheets, from... Figure 2 As can be seen, the multilayer composite solid electrolyte membrane A1 can be matched with a lithium metal anode at room temperature, and the cathode can normally exert its normal specific capacity of 140mAh / g. The battery can stably cycle for more than 80 cycles, demonstrating good cycle stability performance.

[0174] Example 2

[0175] This embodiment provides a method for preparing a multilayer composite co-extruded solid electrolyte membrane that matches a high specific energy electrode:

[0176] (i) Same as Example 1, except that: the same mass of 30LiF·70Li is used. 5.5 PS 4.5 Cl 1.5 (D50=500nm) Replace 30LiF·70Li6PS5Cl (D50=500nm) to obtain the first stable film precursor 1.

[0177] (ii) Same as Example 1, except that: equal masses of 15LiF·85Li are used. 5.5 PS 4.5 Cl 1.5 (D50 = 1 μm) Replace 10LiF·90Li6PS5Cl (D50 = 1 μm). Prepare the first mixed transition film precursor 2.

[0178] (iii) Same as Example 1, except that: equal mass of Li is used. 5.5 PS 4.5 Cl 1.5Sulfide electrolyte membrane precursor 3 was prepared by replacing Li6PS5Cl (D50=5μm) with (D50=5μm).

[0179] (iv) Same as Example 1, except that: equal masses of 15LiF·85Li are used. 5.5 PS 4.5 Cl 1.5 (D50 = 1 μm) Replace 10LiF·90Li6PS5Cl (D50 = 1 μm). Prepare the second mixed transition film precursor 4.

[0180] (v) Same as Example 1, except that: 99% of the composition of 30LiF·70Li was used in equal mass. 5.5 PS 4.5 Cl 1.5 (D50=500nm) Replace 30LiF·70Li6PS5Cl (D50=500nm) to obtain the second stable film precursor 5.

[0181] (vi) Same as in Example 1, except that a multilayer composite solid electrolyte film A2 with a thickness of 25 μm was prepared.

[0182] Example 3

[0183] This embodiment provides a method for preparing a multilayer composite co-extruded solid electrolyte membrane that matches a high specific energy electrode:

[0184] (i) Same as Example 1, except that: equal masses of 30LiF·70Li6PS5Cl are used. 0.5 Br 0.5 (D50=500nm) Replace 30LiF·70Li6PS5Cl (D50=500nm) to obtain the first stable film precursor 1.

[0185] (ii) Same as Example 1, except that: equal masses of 15LiF·85Li6PS5Cl are used. 0.5 Br 0.5 (D50=1μm) Replace 10LiF·90Li6PS5Cl (D50=1μm) to obtain the first mixed transition film precursor 2.

[0186] (iii) Same as Example 1, except that: equal mass of Li6PS5Cl is used. 0.5 Br 0.5 (D50=5μm) Replacing Li6PS5Cl (D50=5μm) yields sulfide electrolyte membrane precursor 3.

[0187] (iv) Same as Example 1, except that: equal masses of 15LiF·85Li6PS5Cl are used.0.5 Br 0.5 (D50=1μm) Replace 10LiF·90Li6PS5Cl (D50=1μm) to obtain the first mixed transition film precursor 4.

[0188] (v) Same as Example 1, except that: equal masses of 30LiF·70Li6PS5Cl are used. 0.5 Br 0.5 (D50=500nm) Replace 30LiF·70Li6PS5Cl (D50=500nm) to obtain the second stable film precursor 5.

[0189] (vi) Same as in Example 1, except that a multilayer composite solid electrolyte film A3 with a thickness of 25 μm was prepared.

[0190] Example 4

[0191] This embodiment provides a method for preparing a multilayer composite co-extruded solid electrolyte membrane that matches a high specific energy electrode:

[0192] (i) 80 parts by weight of the positive electrode component, 18 parts by weight of the mixture of 30LiF·70Li3PS4 (D50 = 500 nm), 1 part by weight of the first binder PTFE (molecular weight 1,000,000 g / mol, D50 = 100 μm, compression ratio 100:1), and 1 part by weight of LLZTO (D50 = 1 μm) were placed in a mortar and mixed until a dough-like mixture was formed. The mixture was then placed between stainless steel plates and flattened to obtain the first stable film precursor 1. The mass ratio of the positive electrode active material (LCO), conductive agent acetylene black, lithium salt LiFSI, and binder polyethylene oxide in the positive electrode component was 85:5:3:7.

[0193] (ii) 98 parts by weight of 10LiF·90Li3PS4 (D50 = 1 μm), 1 part by weight of LLZTO (D50 = 1 μm), and 1 part by weight of PTFE (molecular weight 1,000,000 g / mol, D50 = 100 μm, compression ratio 100:1) were placed in a mortar and mixed until a dough-like mixture was formed. Then the mixture was placed between stainless steel plates and flattened to obtain the first blended transition film precursor 2.

[0194] (iii) 98 parts by weight of Li3PS4 (D50 = 5 μm), 1 part by weight of LLZTO (D50 = 1 μm) and 1 part by weight of PTFE (molecular weight 1,000,000 g / mol, D50 = 100 μm, compression ratio 100:1) were placed in a mortar and mixed until a dough-like mixture was formed. Then the mixture was placed between stainless steel plates and flattened to obtain sulfide electrolyte membrane precursor 3.

[0195] (iv) 98 parts by weight of 10LiF·90Li3PS4 (D50 = 1 μm), 1 part by weight of LLZTO (D50 = 1 μm), and 1 part by weight of PTFE (molecular weight 1,000,000 g / mol, D50 = 100 μm, compression ratio 100:1) were placed in a mortar and mixed until a dough-like mixture was formed. The mixture was then placed between stainless steel plates and flattened to obtain the second blended transition film precursor 4.

[0196] (v) 98 parts by weight of 30LiF·70Li3PS4 (D50 = 500 nm), 1 part by weight of LLZTO (D50 = 1 μm), and 1 part by weight of PTFE (molecular weight 1,000,000 g / mol, D50 = 100 μm, compression ratio 100:1) were placed in a mortar and mixed until a dough-like mixture was formed. The mixture was then placed between stainless steel plates and flattened to obtain the second stable film precursor 5.

[0197] (vi) Same as in Example 1, except that a multilayer composite solid electrolyte film A4 with a thickness of 30 μm was prepared.

[0198] Example 5

[0199] This embodiment provides a method for preparing a multilayer composite co-extruded solid electrolyte membrane that matches a high specific energy electrode:

[0200] (i) Same as Example 1, except that: the same mass of 30LiF·70Li is used. 10 GeP2S 12 (D50=500nm) Replace 30LiF·70Li6PS5Cl (D50=500nm) to obtain the first stable film precursor 1.

[0201] (ii) Same as Example 1, except that: equal masses of 10LiF·90Li are used. 10 GeP2S 12 (D50=1μm) Replace 10LiF·90Li6PS5Cl (D50=1μm) to obtain the second mixed transition film precursor 2.

[0202] (iii) Same as Example 1, except that: equal mass of Li is used. 10 GeP2S 12 (D50=10μm) Replacing Li6PS5Cl (D50=5μm) yields sulfide electrolyte membrane precursor 3.

[0203] (iv) Same as Example 1, except that: equal masses of 10LiF·90Li are used. 10 GeP2S 12(D50=1μm) Replace 10LiF·90Li6PS5Cl (D50=1μm) to obtain the second mixed transition film precursor 4.

[0204] (v) Same as Example 1, except that: equal masses of 30LiF·70Li are used. 10 GeP2S 12 (D50=300nm) Replace 30LiF·70Li6PS5Cl (D50=500nm) to obtain the second stable film precursor 5.

[0205] (vi) In the same manner as in Example 1, a multilayer composite solid electrolyte film A5 was prepared.

[0206] Example 6

[0207] This embodiment provides a method for preparing a multilayer composite co-extruded solid electrolyte membrane that matches a high specific energy electrode:

[0208] (i) 70 parts by weight of the positive electrode component, 29 parts by weight of the mixture of 35LiF·65Li3PS4 (D50 = 500 nm), 0.5 parts by weight of the first binder PVDF (number average molecular weight 500,000 g / mol, D50 = 150 μm, compression ratio 100:1), and 0.5 parts by weight of LLZTO (D50 = 1 μm) were placed in a mortar and mixed until a dough-like mixture was formed. The mixture was then placed between stainless steel plates and flattened to obtain the first stable film precursor 1. The mass ratio of the positive electrode active material (LCO), conductive agent acetylene black, lithium salt LiFSI, and binder polyethylene oxide in the positive electrode component was 85:4:4:7.

[0209] (ii) 99 parts by weight of 15LiF·85Li3PS4 (D50 = 1 μm), 0.5 parts by weight of LLZTO (D50 = 1 μm), and 0.5 parts by weight of PVDF (number average molecular weight 500,000 g / mol, D50 = 150 μm, compression ratio 100:1) were placed in a mortar and mixed until a dough-like mixture was formed. Then the mixture was placed between stainless steel plates and flattened to obtain the first blended transition film precursor 2.

[0210] (iii) 99 parts by weight of Li3PS4 (D50 = 5 μm), 0.5 parts by weight of LLZTO (D50 = 1 μm) and 0.5 parts by weight of PVDF (number average molecular weight of 500,000 g / mol, D50 = 150 μm, compression ratio of 100:1) were placed in a mortar and mixed until a dough-like mixture was formed. Then the mixture was placed between stainless steel plates and flattened to obtain sulfide electrolyte membrane precursor 3.

[0211] (iv) 99 parts by weight of 15LiF·85Li3PS4 (D50 = 1 μm), 0.5 parts by weight of LLZTO (D50 = 1 μm), and 0.5 parts by weight of PVDF (number average molecular weight 500,000 g / mol, D50 = 150 μm, compression ratio 100:1) were placed in a mortar and mixed until a dough-like mixture was formed. Then, the mixture was placed between stainless steel plates and flattened to obtain monoelectrolyte membrane precursor 4.

[0212] (v) 99 parts by weight of 35LiF·65Li3PS4 (D50 = 500 nm), 0.5 parts by weight of LLZTO (D50 = 1 μm), and 0.5 parts by weight of PVDF (number average molecular weight 500,000 g / mol, D50 = 150 μm, compression ratio 100:1) were placed in a mortar and mixed until a dough-like mixture was formed. The mixture was then placed between stainless steel plates and flattened to obtain the second stable film precursor 5.

[0213] (vi) In the same manner as in Example 1, a multilayer composite solid electrolyte film A6 was prepared.

[0214] Example 7

[0215] This embodiment provides a method for preparing a multilayer composite co-extruded solid electrolyte membrane that matches a high specific energy electrode:

[0216] (i) 80 parts by weight of the positive electrode component and 19 parts by weight of 35LiF·65Li 10 GeP2S 12 A mixture of a compound with a D50 of 500 nm, 0.5 parts by weight of a first binder PEO (number average molecular weight 1,200,000 g / mol, D50 = 50 μm, compression ratio 100:1), and 0.5 parts by weight of LLZTO (D50 = 1 μm) were placed in a mortar and mixed until a dough-like mixture was formed. This mixture was then placed between stainless steel plates and flattened to obtain the first stable film precursor 1. The mass ratio of the positive electrode active material (LCO), conductive agent acetylene black, lithium salt LiFSI, and binder polyethylene oxide in the positive electrode component was 83:4:4:9.

[0217] (ii) 99 parts by weight of the composition 15LiF·85Li 10 GeP2S 12 0.5 parts by weight of LLZTO (D50 = 1 μm), 0.5 parts by weight of PEO (number average molecular weight of 1,200,000 g / mol, D50 = 50 μm, compression ratio of 100:1) were placed in a mortar and mixed until a dough-like mixture was formed. Then the mixture was placed between stainless steel plates and flattened to obtain the first blended transition film precursor 2.

[0218] (iii) 99 parts by weight of Li 10 GeP2S 12 0.5 parts by weight of LLZTO (D50 = 5 μm), 0.5 parts by weight of PEO (number average molecular weight 1,200,000 g / mol, D50 = 50 μm, compression ratio 100:1) were placed in a mortar and mixed until a dough-like mixture was formed. Then the mixture was placed between stainless steel plates and flattened to obtain sulfide electrolyte membrane precursor 3.

[0219] (iv) 99 parts by weight of the composition 15LiF·85Li 10 GeP2S 12 0.5 parts by weight of LLZTO (D50 = 1 μm), 0.5 parts by weight of PEO (number average molecular weight 1,200,000 g / mol, D50 = 50 μm, compression ratio 100:1) were placed in a mortar and mixed until a dough-like mixture was formed. Then the mixture was placed between stainless steel plates and flattened to obtain the second blended transition membrane precursor 4.

[0220] (v) 99 parts by weight of the composition 35LiF·65Li 10 GeP2S 12 0.5 parts by weight of LLZTO (D50 = 500 nm), 0.5 parts by weight of PEO (number average molecular weight 1,200,000 g / mol, D50 = 50 μm, compression ratio 100:1) were placed in a mortar and mixed until a dough-like mixture was formed. Then the mixture was placed between stainless steel plates and flattened to obtain the second stable film precursor 5.

[0221] (vi) Same as in Example 1, a multilayer composite solid electrolyte film A7 was obtained.

[0222] Example 8

[0223] This comparative example provides a method for preparing a wet-process multilayer inorganic solid electrolyte Li6PS5Cl membrane:

[0224] (i) 81 parts by weight of the positive electrode component, 13 parts by weight of the mixture of 30LiF·70Li6PS5Cl (D50 = 500 nm), 5 parts by weight of the first binder NBR (1,000,000 g / mol, D50 = 50 μm, compression ratio 100:1), and 1 part by weight of LLZTO (D50 = 1 μm) were added to toluene solvent and dispersed into a homogenate. The slurry was then coated onto a polyester film (PET) substrate using a blade coating method to form a film with a thickness of 100 μm. The film was then transferred to a vacuum oven and dried at 100 °C for 12 hours. After drying, the PET substrate was peeled off to obtain the first stable film precursor 1. The mass ratio of the positive electrode active material (LCO), conductive agent acetylene black, lithium salt LiFSI, and binder polyethylene oxide in the positive electrode component was 85:4:4:7.

[0225] (ii) 94 parts by weight of 10LiF·90Li6PS5Cl (D50 = 1 μm), 1 part by weight of LLZTO (D50 = 1 μm) and 5 parts by weight of the first binder NBR (1,000,000 g / mol, D50 = 50 μm, compression ratio 100:1) were added to toluene solvent and dispersed into a homogenate. The slurry was then coated onto a polyester film (PET) base film by a blade coating method to form a film with a thickness of 100 μm. The film was then transferred to a vacuum oven and dried at 100°C for 12 hours. After drying, the film was removed and the PET base film was peeled off to obtain the first stable film precursor 2.

[0226] (iii) 94 parts by weight of Li6PS5Cl (D50 = 1 μm), 1 part by weight of LLZTO (D50 = 1 μm) and 5 parts by weight of the first binder NBR (1,000,000 g / mol, D50 = 50 μm, compression ratio 100:1) were added to toluene solvent and dispersed into a homogenate. The slurry was then coated onto a polyester film (PET) base film by a blade coating method to form a film with a thickness of 700 μm. The film was then transferred to a vacuum oven and dried at 100°C for 12 hours. After drying, the film was removed and the PET base film was peeled off to obtain the first stable film precursor 3.

[0227] (iv) 94 parts by weight of 10LiF·90Li6PS5Cl (D50 = 1 μm), 1 part by weight of LLZTO (D50 = 1 μm) and 5 parts by weight of the first binder NBR (1,000,000 g / mol, D50 = 50 μm, compression ratio 100:1) were added to toluene solvent and dispersed into a homogenate. The slurry was then coated onto a polyester film (PET) base film by a blade coating method to form a film with a thickness of 100 μm. The film was then transferred to a vacuum oven and dried at 100 °C for 12 hours. After drying, the film was removed and the PET base film was peeled off to obtain the first stable film precursor 4.

[0228] (v) 94 parts by weight of 30LiF·70Li6PS5Cl (D50=500nm), 1 part by weight of LLZTO (D50=1μm) and 5 parts by weight of the first binder NBR (1,000,000g / mol, D50=50μm, compression ratio 100:1) were added to toluene solvent and dispersed into a homogenate. The slurry was then coated onto a polyester film (PET) base film by a blade coating method to form a film with a thickness of 100μm. The film was then transferred to a vacuum oven and dried at 100°C for 12 hours. After drying, the film was removed and the PET base film was peeled off to obtain the first stable film precursor 5.

[0229] (vi) Same as in Example 1, a multilayer composite solid electrolyte film A8 was obtained.

[0230] Example 9

[0231] This comparative example provides a wet method for preparing a multilayer inorganic solid electrolyte, Li, that matches a lithium metal anode. 5.5 PS 4.5 Cl 1.5 Methods for preparing the diaphragm:

[0232] (i) 82 parts by weight of the positive electrode component and 12 parts by weight of 30LiF·70Li 5.5 PS 4.5 Cl 1.5 A mixture of (D50 = 500 nm) binder, 5 parts by weight of the first binder NBR (1,000,000 g / mol, D50 = 50 μm, compression ratio 100:1), and 1 part by weight of LLZTO (D50 = 1 μm) were added to toluene solvent and dispersed into a homogenate. The slurry was then coated onto a polyester film (PET) substrate using a blade coating method to a thickness of 100 μm. The coated film was then transferred to a vacuum oven and dried at 100°C for 12 hours. After drying, the PET substrate was peeled off to obtain the first stable film precursor 1. The mass ratio of the positive electrode active material (LCO), conductive agent acetylene black, lithium salt LiFSI, and binder polyethylene oxide in the positive electrode component was 83:3:5:9.

[0233] (ii) 94 parts by weight of 15LiF·85Li 5.5 PS 4.5 Cl 1.5 One part by weight of LLZTO (D50 = 1 μm) and five parts by weight of the first binder NBR (1,000,000 g / mol, D50 = 50 μm, compression ratio 100:1) were added to toluene solvent and dispersed into a homogenate. The slurry was then coated onto a polyester film (PET) base film by a blade coating method to form a film with a thickness of 100 μm. The film was then transferred to a vacuum oven and dried at 100 °C for 12 hours. After drying, the film was removed and the PET base film was peeled off to obtain the first stable film precursor 2.

[0234] (iii) 94 parts by weight of Li 5.5 PS 4.5 Cl 1.5 One part by weight of LLZTO (D50 = 1 μm) and five parts by weight of the first binder NBR (1,000,000 g / mol, D50 = 50 μm, compression ratio 100:1) were added to toluene solvent and dispersed into a homogenate. The slurry was then coated onto a polyester film (PET) base film by a blade coating method to a thickness of 700 μm. The film was then transferred to a vacuum oven and dried at 100°C for 12 hours. After drying, the film was removed and the PET base film was peeled off to obtain the first stable film precursor 3.

[0235] (iv) 94 parts by weight of 10LiF·90Li 5.5 PS 4.5 Cl 1.5 One part by weight of LLZTO (D50 = 1 μm) and five parts by weight of the first binder NBR (1,000,000 g / mol, D50 = 50 μm, compression ratio 100:1) were added to toluene solvent and dispersed into a homogenate. The slurry was then coated onto a polyester film (PET) base film by a blade coating method to form a film with a thickness of 100 μm. The film was then transferred to a vacuum oven and dried at 100°C for 12 hours. After drying, the film was removed and the PET base film was peeled off to obtain the first stable film precursor 4.

[0236] (v) 94 parts by weight of 35LiF·75Li 5.5 PS 4.5 Cl 1.5 One part by weight of LLZTO (D50 = 500 nm), one part by weight of LLZTO (D50 = 1 μm), and five parts by weight of the first binder NBR (1,000,000 g / mol, D50 = 50 μm, compression ratio 100:1) were added to toluene solvent and dispersed into a homogenate. The slurry was then coated onto a polyester film (PET) base film by a blade coating method to a thickness of 100 μm. The film was then transferred to a vacuum oven and dried at 100 °C for 12 hours. After drying, the film was removed and the PET base film was peeled off to obtain the first stable film precursor 5.

[0237] (vi) Same as in Example 1, a multilayer composite solid electrolyte film A9 was obtained.

[0238] Example 10

[0239] This comparative example provides a wet-prepared multilayer inorganic solid electrolyte Li6PS5Cl 0.5 Br 0.5 Methods for preparing the diaphragm:

[0240] (i) 85 parts by weight of the positive electrode component and 15 parts by weight of 30LiF·70Li6PS5Cl 0.5 Br 0.5 A mixture of (D50 = 500 nm) binder, 5 parts by weight of the first binder NBR (1,000,000 g / mol, D50 = 50 μm, compression ratio 100:1), and 1 part by weight of LLZTO (D50 = 1 μm) were added to toluene solvent and dispersed into a homogenate. The slurry was then coated onto a polyester film (PET) substrate using a blade coating method to a thickness of 100 μm. The coated film was then transferred to a vacuum oven and dried at 100 °C for 12 hours. After drying, the PET substrate was peeled off to obtain the first stable film precursor 1. The mass ratio of the positive electrode active material (LCO), conductive agent acetylene black, lithium salt LiFSI, and binder polyethylene oxide in the positive electrode component was 83:5:3:9.

[0241] (ii) Add 94% 10LiF·90Li6PS5Cl 0.5 Br 0.5 One part by weight of LLZTO (D50 = 1 μm) and five parts by weight of the first binder NBR (1,000,000 g / mol, D50 = 50 μm, compression ratio 100:1) were added to toluene solvent and dispersed into a homogenate. The slurry was then coated onto a polyester film (PET) base film by a blade coating method to form a film with a thickness of 100 μm. The film was then transferred to a vacuum oven and dried at 100 °C for 12 hours. After drying, the film was removed and the PET base film was peeled off to obtain the first stable film precursor 2.

[0242] (iii) 94 parts by weight of Li6PS5Cl 0.5 Br 0.5 One part by weight of LLZTO (D50 = 1 μm) and five parts by weight of the first binder NBR (1,000,000 g / mol, D50 = 50 μm, compression ratio 100:1) were added to toluene solvent and dispersed into a homogenate. The slurry was then coated onto a polyester film (PET) base film by a blade coating method to a thickness of 700 μm. The film was then transferred to a vacuum oven and dried at 100°C for 12 hours. After drying, the film was removed and the PET base film was peeled off to obtain the first stable film precursor 3.

[0243] (iv) 94 parts by weight of 15LiF·85Li6PS5Cl 0.5 Br 0.5One part by weight of LLZTO (D50 = 1 μm) and five parts by weight of the first binder NBR (1,000,000 g / mol, D50 = 50 μm, compression ratio 100:1) were added to toluene solvent and dispersed into a homogenate. The slurry was then coated onto a polyester film (PET) base film by a blade coating method to form a film with a thickness of 100 μm. The film was then transferred to a vacuum oven and dried at 100°C for 12 hours. After drying, the film was removed and the PET base film was peeled off to obtain the first stable film precursor 4.

[0244] (v) 94 parts by weight of 30LiF·70Li6PS5Cl 0.5 Br 0.5 One part by weight of LLZTO (D50 = 500 nm), one part by weight of LLZTO (D50 = 1 μm), and five parts by weight of the first binder NBR (1,000,000 g / mol, D50 = 50 μm, compression ratio 100:1) were added to toluene solvent and dispersed into a homogenate. The slurry was then coated onto a polyester film (PET) base film by a blade coating method to a thickness of 100 μm. The film was then transferred to a vacuum oven and dried at 100 °C for 12 hours. After drying, the film was removed and the PET base film was peeled off to obtain the first stable film precursor 5.

[0245] (vi) Same as in Example 1, a multilayer composite solid electrolyte film A10 was obtained.

[0246] Example 11

[0247] This comparative example provides a method for preparing a multilayer composite co-extruded solid electrolyte membrane without particle size gradient distribution:

[0248] (i) Same as in Example 1, except that the particle size D50 of 30LiF·70Li6PS5Cl is 5μm, and the first stable film precursor 1 is obtained.

[0249] (ii) Same as in Example 1, except that the particle size D50 of 10LiF·90Li6PS5Cl is 5μm, and the second mixed transition film precursor 2 is obtained.

[0250] (iii) Same as in Example 1, sulfide electrolyte membrane precursor 3 was obtained.

[0251] (iv) Same as in Example 1, except that the particle size D50 of 10LiF·90Li6PS5Cl is 5μm, and the second mixed transition film precursor 4 is obtained.

[0252] (v) Same as in Example 1, except that the particle size D50 of 30LiF·70Li6PS5Cl is 5μm, and the second stable film precursor 5 is obtained.

[0253] (vi) Same as in Example 1, except that a multilayer composite solid electrolyte film A11 with a thickness of 50 μm was prepared.

[0254] Example 12

[0255] This embodiment provides a method for preparing a multilayer composite co-extruded solid electrolyte membrane that matches a high specific energy electrode:

[0256] (i) Same as in Example 1, except that 30LiF·70Li6PS5Cl (D50=500nm) is replaced with an equal mass of 35LiF·65Li6PS5Cl (D50=500nm) to obtain the first stable film precursor 1.

[0257] (ii) Same as Example 1, except that 10LiF·90Li6PS5Cl (D50 = 1μm) is replaced with an equal mass of 15LiF·85Li6PS5Cl (D50 = 1μm). First mixed transition film precursor 2 is prepared.

[0258] (iii) Same as Example 1, except that: equal mass of Li is used. 5.5 PS 4.5 Cl 1.5 Sulfide electrolyte membrane precursor 3 was prepared by replacing Li6PS5Cl (D50=5μm) with (D50=5μm).

[0259] (iv) Same as in Example 1, except that 10LiF·90Li6PS5Cl (D50 = 1μm) was replaced with an equal mass of 13LiF·87Li6PS5Cl (D50 = 1μm). The second mixed transition film precursor 4 was thus prepared.

[0260] (v) Same as in Example 1, except that 99% of the composition 35LiF·70Li6PS5Cl (D50=500nm) was replaced with an equal mass of 35LiF·65Li6PS5Cl (D50=500nm) to obtain the second stable film precursor 5.

[0261] (vi) Same as in Example 1, except that a multilayer composite solid electrolyte film A12 with a thickness of 30 μm was prepared.

[0262] Example 13

[0263] Following the method of Example 1, it is best to avoid using a multilayer composite solid electrolyte membrane, specifically:

[0264] (i) Same as in Example 1, except that 30LiF·70Li6PS5Cl (D50=500nm) of equal mass is used to replace 30LiF·70Li6PS5Cl (D50=5μm) to obtain the first stable film precursor 1.

[0265] (ii) Same as Example 1, except that 10LiF·90Li6PS5Cl (D50 = 1μm) of equal mass is used instead of 10LiF·90Li6PS5Cl (D50 = 3μm). First mixed transition film precursor 2 is prepared.

[0266] (iii) Same as in Example 1, except that: Li6PS5Cl (D50 = 5μm) was replaced with an equal mass of Li6PS5Cl (D50 = 1μm) to prepare sulfide electrolyte membrane precursor 3.

[0267] (iv) Same as in Example 1, except that 10LiF·90Li6PS5Cl (D50 = 1μm) was replaced with an equal mass of 10LiF·90Li6PS5Cl (D50 = 3μm). The second mixed transition film precursor 4 was thus prepared.

[0268] (v) Same as in Example 1, except that 30LiF·70Li6PS5Cl (D50=500nm) was replaced with an equal mass of 30LiF·70Li6PS5Cl (D50=5μm) to obtain the second stable film precursor 5.

[0269] (vi) Same as in Example 1, except that a multilayer composite solid electrolyte film A13 with a thickness of 60 μm was prepared.

[0270] Comparative Example 1

[0271] The preparation method of the inorganic solid electrolyte Li6PS5Cl membrane provided in this comparative example differs from that in Example 1 in that the solid electrolyte membrane contains only a single electrolyte layer. 99 parts by weight of Li6PS5Cl (D50 = 1 μm), 0.5 parts by weight of LLZTO (D50 = 1 μm), and 0.5 parts by weight of PTFE (molecular weight 1,000,000 g / mol, D50 = 100 μm, compression ratio 100:1) are placed in a mortar and mixed until a dough-like mixture is formed. This mixture is then placed between stainless steel plates and flattened to obtain the single electrolyte layer membrane precursor.

[0272] The single electrolyte layer membrane preform was compacted and repeatedly co-extruded using a hot roller press to obtain a solid electrolyte film D1 with a thickness of 30 μm.

[0273] The cycling performance of the multilayer composite solid electrolyte membrane obtained above was measured for solid lithium metal batteries.

[0274] With LiCoO2 as the positive electrode, the loading was 36 mg / cm³. 2 Using lithium metal as the negative electrode, charge and discharge tests were conducted with a test voltage range of 2.6-4.3V.

[0275] Using LiCoO2 cathode material 36mg / cm 2 A battery is assembled using the aforementioned sulfide composite solid electrolyte membrane and lithium sheet, from... Figure 2 It can be seen that the prepared sulfide composite electrolyte can be matched with a high-load positive electrode at room temperature, and the positive electrode can exert a normal specific capacity of 124 mAh / g. After 80 battery cycles, the capacity is only 20 mAh / g.

[0276] Comparative Example 2

[0277] This comparative example provides a method for preparing the inorganic solid electrolyte Li6PS5Cl membrane.

[0278] (i) Same as in Example 1, except that 30LiF·70Li6PS5Cl (D50=500nm) is replaced with an equal mass of 10LiF·90Li6PS5Cl (D50=500nm) to obtain the first stable film precursor 1.

[0279] (ii) Same as Example 1, except that 10LiF·90Li6PS5Cl (D50 = 1μm) is replaced with an equal mass of 30LiF·70Li6PS5Cl (D50 = 1μm). First mixed transition film precursor 2 is prepared.

[0280] (iii) Same as in Example 1, sulfide electrolyte membrane precursor 3 was prepared.

[0281] (iv) Same as in Example 1, except that 10LiF·90Li6PS5Cl (D50 = 1μm) was replaced with an equal mass of 30LiF·70Li6PS5Cl (D50 = 1μm). The second mixed transition film precursor 4 was thus prepared.

[0282] (v) Same as in Example 1, except that 99% of the composition 10LiF·70Li6PS5Cl (D50=500nm) was replaced with an equal mass of 10LiF·90Li6PS5Cl (D50=500nm) to obtain the second stable film precursor 5.

[0283] (vi) Same as in Example 1, a multilayer composite solid electrolyte film D2 with a thickness of 30 μm was prepared.

[0284] Comparative Example 3

[0285] This comparative example provides a method for preparing the inorganic solid electrolyte Li6PS5Cl membrane.

[0286] (i) Same as in Example 1, the first stable membrane precursor 1 is obtained.

[0287] (ii) Unlike Example 1, the first mixing transition membrane precursor 2 is not provided.

[0288] (iii) Same as in Example 1, sulfide electrolyte membrane precursor 3 was prepared.

[0289] (iv) Unlike Example 1, the first mixing transition membrane precursor 4 is not provided.

[0290] (v) Same as in Example 1, the second stable membrane precursor 5 is obtained.

[0291] (vi) Same as in Example 1, except that: the first stabilizing film precursor 1, the sulfide electrolyte 3 and the second stabilizing film precursor 5 are stacked in the order of 1-3-5 and initially flattened. They are then repeatedly co-extruded and rolled together using a hot roller press at a temperature of 120°C to obtain a multilayer composite co-extruded solid electrolyte film D3 with a thickness of 20 μm.

[0292] Comparative Example 4

[0293] The preparation method of the inorganic solid electrolyte Li6PS5Cl membrane provided in this comparative example differs from that in Example 8 in that the solid electrolyte membrane contains only a single electrolyte layer. 94 parts by weight of Li6PS5Cl (D50 = 1 μm), 1 part by weight of LLZTO (D50 = 1 μm), and 5 parts by weight of the first binder NBR (1,200,000 g / mol, D50 = 50 μm, compression ratio 100:1) were added to toluene solvent and dispersed into a homogenate. The slurry was then coated onto a polyester film (PET) using a blade coating method to a thickness of 150 μm. The coated film was then transferred to a vacuum oven and dried at 100°C for 12 hours to obtain a single-layer membrane D4.

[0294] (1) Intrinsic contact properties of composite solid electrolyte membranes

[0295] The porosity, compaction density, and peel strength between the composite solid electrolyte membrane and the lithium metal anode layer were tested for the composite solid electrolyte membranes prepared in the examples and comparative examples. The results are shown in Table 1.

[0296] Table 1

[0297]

[0298]

[0299] By comparing various contact performance indicators, it can be found that Examples 1-7 and 11-13, compared with Comparative Examples 1-3, all exhibit similar contact performance indicators. This indicates that the multilayer films prepared by the dry method are comparable to single-layer and sub-multilayer films in terms of particle physical contact, and there is no loss in the overall contact performance of the film due to the increase in the number of film layers. It can also be found that Examples 8-10, compared with Comparative Example 4, all exhibit similar contact performance indicators. This indicates that the multilayer films prepared by the liquid phase method are comparable to single-layer films in terms of particle physical contact, and there is no loss in the overall contact performance of the film due to the increase in the number of film layers.

[0300] (2) Electrochemical stability test of lithium metal:

[0301] (2-1) Linear voltammetric scan tests were performed on the composite solid electrolyte membranes obtained in the examples and comparative examples. The CNT / / SSE / / Li mold cells were assembled, and a negative scan from the open circuit voltage to -0.6V was performed with a voltage step of 0.1mV / s.

[0302] (2-2) The composite solid electrolyte membranes prepared in the examples and comparative examples were subjected to lithium symmetric battery cycle tests and critical current density tests.

[0303] The results are shown in Table 2.

[0304] Table 2

[0305]

[0306] By comparing the peak potential position, curve integral area, cutoff current density, and stable cycle time of lithium symmetric batteries, the lithium insertion / extraction polarization potential and critical current density can be used to compare the electrochemical stability response of different electrolyte membranes to lithium metal. It can be found that the above indicators of the embodiments are all better than those of the comparative examples, indicating that the multilayer composite solid electrolyte membrane with halogen gradient prepared by the present invention, preferably with particle size gradient, has a wider electrochemical reduction window, higher electrochemical stability to lithium metal, and better solid-solid contact performance.

[0307] Furthermore, when the average particle size of the sulfide solid electrolyte in the multilayer composite solid electrolyte membrane has the gradient distribution of the present invention, the solid electrolyte membrane has a wider electrochemical reduction window, higher electrochemical stability to lithium metal, and better solid-solid contact performance.

[0308] (3) Oxidative stability test:

[0309] Linear voltammetric scanning tests were performed on the composite solid electrolyte membranes prepared in the examples and comparative examples. A CNT / / SSE / / Li mold battery was assembled, and a forward scan from the open circuit voltage to 5V was performed with a voltage step of 0.1mV / s. The results are shown in Table 3.

[0310] Table 3

[0311]

[0312] By comparing the peak potential location, curve integral area, and cutoff current density, the oxidation potential stability response of different electrolyte membrane electrodes can be compared. It can be found that the above indicators of the embodiments are all superior to those of the comparative examples. This demonstrates that the multilayer composite solid electrolyte membrane prepared by this invention, especially the multilayer composite solid electrolyte membrane with a halogen gradient, has a wider electrochemical reduction window, higher oxidation stability, and better solid-solid contact performance.

[0313] Furthermore, when the average particle size of the sulfide solid electrolyte in the multilayer composite solid electrolyte membrane has the gradient distribution of the present invention, the solid electrolyte membrane has a wider electrochemical reduction window, higher oxidation stability, and better solid-solid contact performance.

[0314] (4) Ion conduction performance test:

[0315] The ionic conductivity of the sulfide multilayer composite solid electrolyte membranes (excluding the first stable membrane layer 1) prepared in the examples and comparative examples was tested, and the test results are shown in Table 4.

[0316] The testing method is as follows:

[0317] The conductivity of multilayer composite solid electrolyte membranes (SSEs) was determined using electrochemical impedance spectroscopy (EIS). Before measurement, a blocked battery was assembled in an argon-filled glove box. The SSEs were punched into 10 mm diameter discs and sandwiched between two stainless steel (SS) electrodes, forming a stainless steel / composite SSE / stainless steel (SS / SSEs / SS) measurement system. EIS was performed using an electrochemical workstation. During the test, the AC perturbation amplitude was set to 5 mV, and the scan frequency range was 100 kHz–7 MHz. The temperature of the measurement system was 25 °C.

[0318] Table 4

[0319]

[0320]

[0321] By comparing the examples with the comparative examples, all samples showed similar ionic conductivity of ≥0.1 mS / cm, indicating that the multilayer membranes prepared by the dry method are comparable to single-layer and sub-multilayer membranes in terms of ionic conductivity, and there is no excessive reduction in the overall ionic conductivity of the membrane due to the increase of membrane layers or the introduction of fluorine components.

[0322] Furthermore, ionic conductivity tests were conducted using Examples 1-3, and the ionic conductivity of the sulfide composite electrolyte membranes prepared from the selected target polymers all exceeded 10. -3 S / cm.

[0323] Ionic conductivity tests were conducted in Examples 4-7, and the ionic conductivity of the sulfide composite electrolyte membranes prepared from the selected target polymers was close to 10. -3 S / cm.

[0324] Ionic conductivity tests were conducted in Examples 8-13, and the ionic conductivity of the sulfide composite electrolyte membranes prepared from the selected target polymers all exceeded 10. -4 The S / cm ratio demonstrates that wet film deposition is less favorable for the ionic conductivity of multilayer composite membrane materials compared to dry film deposition. Multilayer composite membrane materials without particle size gradients exhibit poor contact performance and low ionic conductivity. Composite electrolyte membranes with excessively high fluorine content also show poor interfacial ion transport and low ionic conductivity.

[0325] (5) Solid-state battery testing:

[0326] By comparing the solid-state battery cycle data of Example 1 and Comparative Example 1, it can be seen that (e.g.) Figure 2 As shown, the multilayer co-extruded composite solid electrolyte membrane designed in this invention has a higher first-cycle discharge specific capacity and superior cycle performance, demonstrating the potential of this multilayer composite electrolyte membrane in full batteries.

[0327] In summary, the multilayer co-extruded composite electrolyte membrane prepared by this invention has advantages such as high oxidation stability and high stability against lithium metal reduction. Furthermore, the multilayer co-extruded composite electrolyte membrane prepared by this invention is comparable to the unmodified electrolyte membrane in terms of porosity, compaction density, and ionic conductivity. Therefore, the multilayer co-extruded composite electrolyte membrane prepared by this invention can effectively improve the cycle life of all-solid-state lithium batteries and has practical application value.

[0328] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A multilayer composite solid electrolyte membrane, characterized in that, The solid electrolyte membrane includes a first stable membrane layer 1, a first mixed transition membrane layer 2, a sulfide electrolyte membrane layer 3, a second mixed transition membrane layer 4, and a second stable membrane layer 5, which are stacked sequentially. The first stable film layer 1 includes sulfide electrolytes S-SSEs and LiX. 1 The mixture, first binder, oxide electrolyte and positive electrode component; The first mixed transition film layer 2, the second mixed transition film layer 4, and the second stable film layer 5 each independently include sulfide electrolytes S-SSEs and LiX. 1 The admixture, the first binder, and the oxide electrolyte; The sulfide electrolyte membrane 3 includes sulfide electrolytes S-SSEs, a first binder, and an oxide electrolyte; Along the direction from the sulfide electrolyte membrane layer 3 to the first stable membrane layer 1, LiX 1 The content of [ ] shows an increasing trend; Along the direction from the sulfide electrolyte membrane layer 3 to the second stable membrane layer 5, LiX 1 The content of [ ] shows an increasing trend; Among them, X 1 It is a halogen.

2. The multilayer composite solid electrolyte membrane according to claim 1, wherein, X 1 It is F.

3. The multilayer composite solid electrolyte membrane according to claim 1, wherein, The sulfide electrolytes S-SSEs are selected from compounds of formula I, Li 4-x Ge 1-x P x S4, Li 10 GeP2S 12 Li 10 SnP2S 12 At least one of Li2S-P2S5, Li2S-SiS2, Li2S-B2S3, LiSiPSCl, LiSiPSBr and LiSiPSI, wherein 0≤x≤2; Li 6-a PS 5-a Cl 1+a-b X 2 b Formula I; Among them, X 2 It is at least one of Cl, Br or I, and 0≤a≤3 and 0≤b≤3.

4. The multilayer composite solid electrolyte membrane according to claim 3, wherein, X 2 It is at least one of Cl or Br.

5. The multilayer composite solid electrolyte membrane according to claim 1 or 2, wherein, Based on the total molar amount of the admixtures in the first stable film layer 1, LiX 1 The molar content is 20 mol%-40 mol%; And / or, based on the total molar amount of the admixtures in the first mixed transition film layer 2, LiX 1 The molar content is 0.5 mol%-20 mol%; And / or, based on the total molar amount of the admixtures in the second blended transition film layer 4, LiX 1 The molar content is 0.5 mol%-20 mol%; And / or, based on the total molar amount of the admixtures in the second stable film layer 5, LiX 1 The molar content is 20mol%-40mol.

6. The multilayer composite solid electrolyte membrane according to claim 1 or 2, wherein, Along the direction from the sulfide electrolyte membrane layer 3 to the first stable membrane layer 1, the average particle size of the sulfide electrolytes S-SSEs shows a decreasing trend. Along the direction from the sulfide electrolyte membrane layer 3 to the second stable membrane layer 5, the average particle size of the sulfide electrolyte S-SSEs decreases.

7. The multilayer composite solid electrolyte membrane according to claim 1 or 2, wherein, The average particle size of the sulfide electrolytes S-SSEs in the first stable film layer 1 is 50-400 nm; And / or, the average particle size of the sulfide electrolytes S-SSEs in the first mixed transition film layer 2 is 0.4-1 μm; And / or, the average particle size of the sulfide electrolytes S-SSEs in the sulfide electrolyte membrane layer 3 is 1-10 μm; And / or, the average particle size of the sulfide electrolytes S-SSEs in the second blended transition film layer 4 is 0.4-1 μm; And / or, the average particle size of the sulfide electrolytes S-SSEs in the second stable film layer 5 is 50-400 nm.

8. The multilayer composite solid electrolyte membrane according to claim 1 or 2, wherein, The thickness of the multilayer composite solid electrolyte membrane is 10-500 μm; And / or, the thickness of the first stabilizing film 1 is 0.5-1 μm; And / or, the thickness of the first mixed transition film layer 2 is 0.5-1 μm; And / or, the thickness of the sulfide electrolyte membrane layer 3 is 4-11 μm; And / or, the thickness of the second mixed transition film layer 4 is 0.5-1 μm; And / or, the thickness of the second stabilizing film 5 is 0.5-1 μm.

9. The multilayer composite solid electrolyte membrane according to claim 8, wherein, The thickness of the multilayer composite solid electrolyte membrane is 10-100 μm.

10. The multilayer composite solid electrolyte membrane according to claim 9, wherein, The thickness of the multilayer composite solid electrolyte membrane is 6-15 μm.

11. The multilayer composite solid electrolyte membrane according to claim 1 or 2, wherein, The first stable film layer 1 comprises 9.4-39.76 parts by weight of the admixture, 0.05-2 parts by weight of the first binder, 0.01-0.4 parts by weight of the oxide electrolyte and 60-90 parts by weight of the positive electrode component; And / or, the first blended transition film layer 2 includes 94-99.4 parts by weight of the blend, 0.5-5 parts by weight of the first binder and 0.1-1 parts by weight of the oxide electrolyte; And / or, the sulfide electrolyte membrane layer 3 includes 94-99.4 parts by weight of sulfide electrolytes S-SSEs, 0.5-5 parts by weight of a first binder and 0.1-1 parts by weight of oxide electrolyte; And / or, the second blended transition film layer 4 includes 94-99.4 parts by weight of the blend, 0.5-5 parts by weight of the first binder and 0.1-1 parts by weight of the oxide electrolyte; And / or, the second stable film layer 5 includes 94-99.4 parts by weight of an admixture, 0.5-5 parts by weight of a first binder, and 0.1-1 parts by weight of an oxide electrolyte.

12. The multilayer composite solid electrolyte membrane according to claim 1 or 2, wherein, The first adhesive is selected from at least one of polyvinylidene fluoride, polytetrafluoroethylene, (vinylidene fluoride-hexafluoropropylene) copolymer, polyethylene oxide, polyacrylonitrile and styrene-butadiene rubber; And / or, the oxide electrolyte is selected from at least one of lithium lanthanum zirconium oxide, lithium lanthanum zirconium tantalum oxide, lithium titanium aluminum phosphate, and lithium germanium aluminum phosphate; And / or, the average particle size of the first adhesive is 10-1000 μm; And / or, the number average molecular weight of the first adhesive is greater than or equal to 100,000 g / mol, and the compression ratio is 1-10000:

1.

13. The multilayer composite solid electrolyte membrane according to claim 12, wherein, The oxide electrolyte is selected from lithium lanthanum zirconium oxide and / or lithium lanthanum zirconium tantalum oxide with garnet structure.

14. The multilayer composite solid electrolyte membrane according to claim 1 or 2, wherein, The positive electrode component includes a positive electrode active material, a conductive agent, a lithium salt, and a second binder; The mass ratio of the positive electrode active material, the conductive agent, the lithium salt, and the second binder is 65-98:0.5-10:0.5-10:1-15.

15. The multilayer composite solid electrolyte membrane according to claim 14, wherein, The positive electrode active material is selected from at least one of lithium cobalt oxide, lithium manganese oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, lithium iron phosphate, lithium manganese iron phosphate, lithium manganese phosphate, and lithium-rich manganese-based materials.

16. The multilayer composite solid electrolyte membrane according to claim 14, wherein, The second binder is selected from small molecule organics and / or high molecular polymers.

17. The multilayer composite solid electrolyte membrane according to claim 1 or 2, wherein, The porosity of the multilayer composite solid electrolyte membrane is 1%-20%; And / or, the compaction density of the multilayer composite solid electrolyte membrane is 2 g / cm³. 3 -6g / cm 3 ; And / or, the peel strength of the multilayer composite solid electrolyte membrane is 300-800 N / m; And / or, the ionic conductivity of the multilayer composite solid electrolyte membrane is ≥10. -4 S / cm.

18. A method for preparing a multilayer composite solid electrolyte membrane, characterized in that, The preparation method includes the following steps: S1, positive electrode components, sulfide electrolyte S-SSEs, LiX 1 The first binder and the oxide electrolyte are mixed to obtain the first stable film precursor 1; S2, sulfide electrolytes S-SSEs, LiX 1 The first binder and oxide electrolyte are mixed to obtain the first mixed transition film precursor 2; S3. The sulfide electrolyte S-SSEs, the first binder and the oxide electrolyte are mixed to obtain the sulfide electrolyte membrane precursor 3. S4, sulfide electrolytes S-SSEs, LiX 1 The first binder and oxide electrolyte are mixed to obtain the second mixed transition film precursor 4; S5, sulfide electrolytes S-SSEs, LiX 1 The first binder and oxide electrolyte are mixed to obtain the second stable membrane precursor 5; Among them, X 1 It is a halogen; S6. The first stabilizing membrane precursor 1, the first mixed transition membrane precursor 2, the sulfide electrolyte 3, the second mixed transition membrane precursor 4, and the second stabilizing membrane precursor 5 are sequentially combined to obtain a multilayer composite solid electrolyte membrane. Among them, LiX in each step 1 The dosage is such that, along the direction from the sulfide electrolyte membrane layer 3 to the first stable membrane layer 1, LiX 1 The content of LiX shows an increasing trend; along the direction from the sulfide electrolyte membrane layer 3 to the second stable membrane layer 5, the content of LiX increases. 1 The content of [something] shows an increasing trend.

19. The preparation method according to claim 18, wherein, X 1 It is F.

20. The preparation method according to claim 18 or 19, wherein, In step S6, the composite method includes: sequentially coating and drying the first stabilizing membrane precursor 1, the first blended transition membrane precursor 2, the sulfide electrolyte 3, the second blended transition membrane precursor 4, and the second stabilizing membrane precursor 5. Alternatively, the composite method includes: sequentially stacking the first stabilizing membrane precursor 1, the first blended transition membrane precursor 2, the sulfide electrolyte 3, the second blended transition membrane precursor 4, and the second stabilizing membrane precursor 5, and then performing co-extrusion.

21. The preparation method according to claim 20, wherein, The drying conditions include: a drying temperature of 60-200℃ and a drying time of 0.5-5h; And / or, the co-extrusion is integral hot pressing, with a hot pressing temperature of 40-100℃.

22. A multilayer composite solid electrolyte membrane prepared by any one of claims 18-21.

23. The application of the multilayer composite solid electrolyte membrane according to any one of claims 1-17 and 22 in solid-state batteries.

24. An all-solid-state battery, characterized in that, The all-solid-state battery includes a positive electrode, a negative electrode, and a multilayer composite solid electrolyte membrane as described in any one of claims 1-17 and 22, wherein the current collector of the positive electrode is located on one side of the first stabilizing membrane layer 1, and the negative electrode is located on one side of the second stabilizing membrane layer 5.

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