Composite electrolyte membrane and preparation method thereof, all-solid-state battery and electric equipment

Abstract

The invention provides a composite electrolyte membrane and a preparation method thereof, an all-solid-state battery and electric equipment. The composite electrolyte membrane comprises a polymer layer and a solid electrolyte layer, the polymer layer comprises a polymer, a lithium salt and an additive, and the thickness of the polymer layer is 1-5 [mu] m; the solid electrolyte layer comprises a solid electrolyte and a binder, and the thickness of the solid electrolyte layer is 10-70 [mu] m. The composite electrolyte membrane is used for achieving the effect of reducing the short-circuit rate of the all-solid-state battery.

Description

Technical Field

[0001] The present application relates to the field of solid-state battery technology, and in particular to a composite electrolyte membrane and a preparation method thereof, an all-solid-state battery, and electrical equipment. Background Art

[0002] Traditional lithium-ion batteries use liquid electrolytes, which pose safety risks such as flammability and volatility. All-solid-state batteries use solid electrolytes instead of liquid electrolytes, fundamentally solving safety issues such as battery leakage, combustion and explosion, and are an important direction for the future development of battery technology.

[0003] Solid-state electrolytes are the core components of all-solid-state batteries. Their properties (such as ionic conductivity, interfacial stability, and mechanical strength) directly determine the safety, energy density, and cycle life of all-solid-state batteries. Currently, there are three main types of solid-state electrolytes: polymer-based solid-state electrolytes, oxide-based solid-state electrolytes, and sulfide-based solid-state electrolytes. They replace traditional liquid electrolytes, providing a directional migration path for charge carriers such as lithium ions, while also isolating the battery's positive and negative electrodes to prevent short circuits.

[0004] However, the inventors have found that the all-solid-state battery prepared using the above-mentioned solid-state electrolyte has a high short-circuit rate. Summary of the Invention

[0005] The embodiments of the present application provide a composite electrolyte membrane and a preparation method thereof, an all-solid-state battery, and an electrical device to achieve the effect of reducing the short-circuit rate of the all-solid-state battery.

[0006] In a first aspect, an embodiment of the present application provides a composite electrolyte membrane, comprising: a polymer layer and a solid electrolyte layer;

[0007] The polymer layer includes a polymer, a lithium salt and an additive, and the thickness of the polymer layer is 1-5 μm;

[0008] The solid electrolyte layer includes a solid electrolyte and a binder, and the thickness of the solid electrolyte layer is 10-70 μm.

[0009] In one possible embodiment, the mass ratio of the polymer, the lithium salt, and the additive is 1:0.2-0.5:0.05-0.15;

[0010] The mass ratio of the solid electrolyte to the binder is 1:0.005-0.025.

[0011] In one possible embodiment, the additive is selected from at least one of cesium hexafluorophosphate, rubidium hexafluorophosphate, cesium nitrate, and rubidium nitrate.

[0012] In one possible embodiment, the polymer is selected from at least one of polyethylene oxide, polyethylene glycol, polymethacrylate, polyethylene glycol dimethacrylate, and polyacrylonitrile;

[0013] The lithium salt is selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium bis(oxalatoborate), lithium bis(trifluoromethylsulfonylimide), lithium bis(fluorosulfonylimide), and lithium bis(fluorooxalatoborate).

[0014] In one possible embodiment, the solid electrolyte is selected from at least one of a sulfide solid electrolyte, a halide solid electrolyte, and an oxide solid electrolyte;

[0015] The binder is selected from at least one of polyvinylidene fluoride, polytetrafluoroethylene, polyacrylic acid, styrene-butadiene rubber, nitrile rubber, polyamide, polyvinyl alcohol, polyethyleneimine, polyimide, and hydrogenated styrene-butadiene block copolymer.

[0016] In a second aspect, an embodiment of the present application provides a method for preparing a composite electrolyte membrane, comprising:

[0017] Mixing the polymer, lithium salt, additive and the first solvent to obtain slurry A;

[0018] mixing the solid electrolyte, the binder and the second solvent to obtain slurry B;

[0019] Slurry B is coated on the electrolyte membrane support and dried to obtain a solid electrolyte layer;

[0020] Slurry A is constructed on the solid electrolyte layer and dried to obtain a composite electrolyte membrane.

[0021] In one possible embodiment, slurry A is constructed on the solid electrolyte layer, comprising:

[0022] The slurry A is constructed on the solid electrolyte layer by 3D printing or screen printing.

[0023] In one possible embodiment, the first solvent is selected from at least one of acetonitrile, anisole, chloroform, dichloroethane, and dimethylformamide;

[0024] The second solvent is selected from at least one of a benzene solvent, an aliphatic hydrocarbon solvent containing 4 or more carbon atoms, and an ester solvent.

[0025] In a third aspect, an embodiment of the present application provides an all-solid-state battery, comprising the composite electrolyte membrane, the positive electrode sheet, and the negative electrode sheet as described in the first aspect and / or various possible embodiments of the first aspect.

[0026] In a fourth aspect, an embodiment of the present application provides an electrical device, comprising the all-solid-state battery as described in the third aspect above.

[0027] The composite electrolyte membrane and its preparation method, all-solid-state battery, and electrical equipment provided in the embodiments of the present application achieve multi-dimensional improvements in ionic conductivity, interface stability, and safety through the coordinated design of the polymer layer and the solid electrolyte layer. The polymer layer, with its flexibility and interface affinity, forms a low-impedance dynamic interface with the lithium metal negative electrode and the oxide positive electrode. Its elastic characteristics can effectively buffer the volume changes during the electrode charge and discharge process, significantly reducing the risk of interface delamination; the solid electrolyte layer, through the synergistic effect of the high-ionic conductivity inorganic solid electrolyte matrix and the binder, constructs a stable ion transmission channel while inhibiting the lateral growth of lithium dendrites. The anions in the additive participate in the formation of a dense and self-healing solid electrolyte interface (SEI) film, which, combined with the electrostatic shielding effect, promotes the uniform deposition of lithium ions, making the lithium deposition morphology smoother and denser, thereby reducing the risk of lithium dendrites piercing the electrolyte membrane. This multi-component synergistic effect significantly optimizes the mechanical strength and chemical stability of the electrode-electrolyte interface, effectively inhibiting the propagation of interfacial cracks and the penetration of lithium dendrites caused by excessive local current density. In addition, the flexibility of the composite electrolyte membrane also improves the structural integrity of the battery during the cycle process, reducing the risk of internal short circuit caused by interface stratification or electrolyte rupture. Ultimately, while ensuring high energy density and long cycle life, it provides reliable protection for the safe application of all-solid-state batteries. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0029] Figure 1 A schematic structural diagram of a composite electrolyte membrane provided in this application;

[0030] Figure 2 A schematic structural diagram of an all-solid-state battery provided in this application.

[0031] Reference numerals:

[0032] 10. polymer layer;

[0033] 20. Solid electrolyte layer;

[0034] 30. Positive electrode;

[0035] 40. Negative electrode.

[0036] The above drawings illustrate specific embodiments of the present application, which will be described in more detail below. These drawings and the textual description are not intended to limit the scope of the present application in any way, but rather to illustrate the concepts of the present application to those skilled in the art by reference to specific embodiments. DETAILED DESCRIPTION

[0037] Exemplary embodiments will be described in detail herein, with examples illustrated in the accompanying drawings. In the following description, when referring to the drawings, identical numerals in different figures represent identical or similar elements, unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all embodiments consistent with the present application. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present application, as detailed in the appended claims.

[0038] Solid-state batteries, as the core representative of next-generation lithium battery technology, inherit the advantages of traditional lithium batteries such as high energy density and long cycle life. With their excellent safety and potential for increased energy density, they are gradually becoming the focus of attention in fields such as electric vehicles, energy storage systems, and consumer electronics. Although traditional liquid lithium batteries have been widely used in various fields, the flammable and explosive liquid electrolytes they use are prone to safety accidents under extreme conditions, and their energy density is close to the theoretical limit, making it difficult to meet the demand for higher performance in the future. Solid-state batteries use solid electrolytes instead of liquid electrolytes to achieve the conduction of lithium ions between the positive and negative electrodes, fundamentally solving the safety issues of liquid lithium batteries and promising to significantly improve energy density and cycle life.

[0039] In related technologies, solid electrolytes in solid-state batteries play a vital role. Taking sulfide solid electrolytes as an example, they have become a research hotspot in the field of solid-state batteries due to their high ionic conductivity, good mechanical strength and wide electrochemical window. The working principle of sulfide solid electrolytes is based on the rapid migration of lithium ions in the sulfide lattice. Their ionic conductivity can be close to or even exceed that of liquid electrolytes, ensuring the efficient charge and discharge performance of the battery. At the same time, the high mechanical strength of sulfide solid electrolytes can effectively inhibit the growth of lithium dendrites and prevent battery short circuits, thereby greatly improving the safety and cycle life of the battery. In addition, sulfide solid electrolytes have good compatibility with lithium metal negative electrodes, can support the use of lithium metal negative electrodes, and further improve the energy density of the battery.

[0040] However, existing solid-state electrolytes still face many challenges in the application of solid-state batteries, among which the high battery short-circuit rate is one of the problems that need to be solved urgently. The interfacial stability between the solid-state electrolyte and the lithium metal negative electrode is a key factor affecting the battery short-circuit rate. During the charge and discharge process, the lithium metal negative electrode will undergo uneven deposition to form lithium dendrites. Once these lithium dendrites penetrate the solid electrolyte membrane, they will directly connect the positive and negative electrodes, causing the battery to short-circuit. Especially for polymer solid electrolytes, due to their relatively low mechanical strength, they are more easily penetrated by lithium dendrites. In addition, the solid-solid interface contact resistance between the solid electrolyte and the positive and negative electrode materials is high, resulting in excessive local current density, further accelerating the growth of lithium dendrites and the occurrence of battery short circuits. The presence of interfacial contact resistance and chemical reactions will also cause battery capacity decay.

[0041] In summary, solid-state batteries, as the next generation of lithium-ion battery technology, offer significant advantages in safety and energy density. However, existing solid-state electrolytes still suffer from high battery short-circuit rates and insufficient ionic conductivity in their applications.

[0042] Based on the above problems, the present application provides a composite electrolyte membrane and its preparation method, an all-solid-state battery, and an electrical device. The composite electrolyte membrane combines a polymer layer and a solid electrolyte layer, wherein the polymer layer not only provides good interface compatibility and reduces the interface resistance between the solid electrolyte layer and the lithium metal negative electrode, but also effectively inhibits the formation and growth of lithium dendrites through its unique physical and chemical properties. Lithium dendrites are the main factor in solid-state battery short circuits, and the polymer layer can act as a barrier to prevent lithium dendrites from penetrating the solid electrolyte layer, thereby greatly reducing the risk of battery short circuits. At the same time, the high mechanical strength of the solid electrolyte layer itself also provides additional protection against lithium dendrite penetration. The combination of the polymer layer and the solid electrolyte layer enables the composite electrolyte membrane to significantly improve the safety of the battery and reduce the short circuit rate of the battery while maintaining high ionic conductivity.

[0043] The following specific embodiments describe in detail the technical solution of the present application and how the technical solution of the present application solves the above-mentioned technical problems. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0044] Figure 1 This is a schematic diagram of the structure of a composite electrolyte membrane provided in an embodiment of the present application. Figure 1 As shown, the composite electrolyte membrane of this embodiment includes a polymer layer 10 and a solid electrolyte layer 20 .

[0045] The polymer layer 10 includes a polymer, a lithium salt and an additive, and has a thickness of 1-5 μm.

[0046] The solid electrolyte layer 20 includes a solid electrolyte and a binder, and the thickness of the solid electrolyte layer is 10-70 μm.

[0047] The thickness of the polymer layer 10 can be 1 μm, 2 μm, 3 μm, 4 μm, or 5 μm.

[0048] The thickness of the solid electrolyte layer 20 may be 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 65 μm, or 70 μm.

[0049] In this embodiment, the thickness of the polymer layer 10 is controlled within the range of 1-5 μm. This thickness ensures that the polymer layer 10 can fully exert its interface modification and lithium dendrite suppression functions, and avoids the increase in ion transmission resistance caused by excessive thickness. At the same time, the high mechanical strength of the solid electrolyte layer 20 itself also provides additional protection against lithium dendrite penetration. The thickness of the solid electrolyte layer 20 is designed to be 10-70 μm. This range ensures sufficient mechanical strength to resist the penetration of lithium dendrites and ensures that lithium ions can be efficiently transmitted therein. By optimizing the combination of the polymer layer 10 and the solid electrolyte layer 20, a more efficient ion transmission channel can be formed, reducing the resistance during ion transmission, thereby improving the charge and discharge performance of the battery.

[0050] In summary, the composite electrolyte membrane in this embodiment effectively solves the problems of high battery short-circuit rate and insufficient ionic conductivity faced by existing solid-state electrolytes in solid-state battery applications through its unique structure and composition. It can not only reduce the battery short-circuit rate and improve the battery safety, but also improve the ionic conductivity and optimize the battery's charge and discharge performance.

[0051] In one possible embodiment, the mass ratio of the polymer, the lithium salt, and the additive is 1:0.2-0.5:0.05-0.15; and the mass ratio of the solid electrolyte to the binder is 1:0.005-0.025.

[0052] Specifically, when the mass fraction of the polymer is 1, the mass fraction of the lithium salt can be 0.2, 0.3, 0.4, or 0.5, and the mass fraction of the additive can be 0.05, 0.08, 0.1, 0.12, or 0.15.

[0053] When the mass fraction of the solid electrolyte is 1, the mass fraction of the binder can be 0.005, 0.008, 0.01, 0.015, 0.020, or 0.025.

[0054] In this embodiment, by adjusting the ratio of polymer to lithium salt, the dispersion of the lithium salt in the polymer can be optimized, increasing the dissociation and migration rate of lithium ions. Setting the polymer to lithium salt mass ratio between 1:0.2 and 0.5 ensures both the stability and flexibility of the polymer matrix and the sufficient dissolution and ionization of the lithium salt, thereby improving the ionic conductivity of the solid electrolyte.

[0055] Furthermore, the interfacial compatibility between the polymer layer and the solid electrolyte layer is crucial to the overall performance of solid-state batteries. By adjusting the ratio of polymer to lithium salt and additives, the surface properties of the polymer layer can be improved, allowing it to form a tighter bond with the solid electrolyte layer. This tight bond helps reduce interfacial resistance and improve lithium ion transport efficiency.

[0056] As the core component of solid-state batteries, the mechanical strength of solid electrolytes is of great significance for preventing lithium dendrite penetration and battery short circuits. The role of the binder is to tightly combine the solid electrolyte and the electrode material to form a stable electrode structure. An appropriate amount of binder can improve the adhesion and conductivity of the electrode material, thereby optimizing the charge and discharge performance of the battery. By adjusting the ratio of solid electrolyte to binder, it can be ensured that the solid electrolyte layer has sufficient mechanical strength and toughness to resist the mechanical stress during the charge and discharge process of the battery. In this embodiment, the mass ratio of solid electrolyte to binder is set between 1:0.005-0.025, which not only ensures the mechanical strength of the solid electrolyte layer, but also avoids the decrease in ionic conductivity that may be caused by excessive binder.

[0057] In summary, the chemical stability of solid electrolytes and lithium metal negative electrodes is poor, and side reactions are prone to form interface layers, resulting in increased interface impedance. At the same time, the interface compatibility of solid electrolytes with oxide positive electrodes also needs to be improved through coating or buffer layers. However, polymer materials have good interface compatibility with lithium metal negative electrodes and oxide positive electrodes, and can easily form a stable interface with low impedance. The elasticity of polymer materials can adapt to changes in electrode volume and reduce the risk of interface peeling. Based on this consideration, this embodiment uses a composite electrolyte membrane comprising a polymer layer and a solid electrolyte layer, which can reduce interface impedance and reduce battery short circuit rate while ensuring ionic conductivity.

[0058] In one possible embodiment, the additive is selected from at least one of cesium hexafluorophosphate (CsPF6), rubidium hexafluorophosphate (RbPF6), cesium nitrate (CsNO3), and rubidium nitrate (RbNO3).

[0059] It is understood that in lithium-ion batteries, the SEI film is a thin film covering the surface of the negative electrode, which is mainly composed of electrolyte decomposition products. This film is crucial for protecting the negative electrode and improving battery performance. - or PF6- Anionic additive, NO3 - or PF6 - Anions can participate in the formation of SEI film on the negative electrode surface, making the SEI film more stable and effectively preventing direct contact between the composite electrolyte membrane and the negative electrode, thereby reducing the decomposition of the composite electrolyte membrane and the corrosion of the negative electrode.

[0060] During the battery charging and discharging process, charge accumulation occurs on the negative electrode surface, resulting in an increase in the local electric field strength. This uneven distribution of electric field strength may cause uneven deposition of lithium, forming unfavorable morphologies such as lithium dendrites. - or PF6 - Anions are electronegative and can attract lithium ions released from the positive electrode, thus forming an electrostatic shielding layer on the surface of the negative electrode. This shielding layer can even out the electric field distribution on the surface of the negative electrode and promote the uniform deposition of lithium. At the same time, when lithium dendrites begin to form, NO3 - or PF6 - Anions can also dissolve it or inhibit its further growth through chemical reactions, thereby achieving a self-healing effect.

[0061] In practical applications, multiple additives can be selected and used in combination to fully utilize their synergistic effects. For example, the combination of cesium nitrate and cesium hexafluorophosphate may be able to provide a stable SEI film and achieve a self-healing electrostatic shielding effect, thereby further improving the coulombic efficiency of the lithium anode and the morphological quality of the deposited lithium.

[0062] In summary, the role of additives in composite electrolyte membranes is primarily reflected in stabilizing the SEI film and providing a self-healing electrostatic shielding mechanism. These effects together promote uniform lithium deposition and protect the lithium anode, thereby improving the performance and safety of lithium-ion batteries.

[0063] In one possible embodiment, the polymer is selected from at least one of polyethylene oxide (PEO), polyethylene glycol (PEG), polymethacrylate (PMMA), polyethylene glycol dimethacrylate (PEGDMA), and polyacrylonitrile (PAN);

[0064] The lithium salt is selected from at least one of lithium hexafluorophosphate (LiFP6), lithium tetrafluoroborate (LiBF4), lithium bis(oxalatoborate) (LiBOB), lithium bis(trifluoromethylsulfonylimide) (LiTFSI), lithium bis(fluorosulfonylimide) (LiFSI), and lithium bis(fluorooxalatoborate) (LiODFB).

[0065] In this embodiment, the above-mentioned polymer material is selected as the matrix material of the polymer layer in the composite electrolyte membrane, which can provide good flexibility and film-forming properties, help to form a stable and uniform electrolyte membrane, and the polymer material has a certain ion conductivity, which helps to improve the overall performance of the battery.

[0066] Lithium salts, as ion sources in composite electrolyte membranes, are crucial for the battery's ionic conductivity and electrochemical stability. Combining one or more of these lithium salts can optimize the composite electrolyte membrane's ionic conductivity, improving the battery's charge-discharge efficiency and cycling stability. Furthermore, lithium salts interact well with the polymer matrix material, further enhancing the overall performance of the composite electrolyte membrane.

[0067] In one possible embodiment, the solid electrolyte is selected from at least one of a sulfide solid electrolyte, a halide solid electrolyte, and an oxide solid electrolyte;

[0068] For example, lithium aluminum titanium phosphate (LATP) and lithium indium hexachloride (Li3InCl6).

[0069] The binder is selected from at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyacrylic acid (PAA), styrene-butadiene rubber (SBR), nitrile rubber (NBR), polyamide (PAI), polyvinyl alcohol (PVA), polyethyleneimine (PEI), polyimide (PI), and hydrogenated styrene-butadiene block copolymer (SEBS).

[0070] In this embodiment, the introduction of a solid-state electrolyte significantly improves battery safety and energy density. Sulfide, halide, and oxide solid-state electrolytes each possess unique advantages, such as high ionic conductivity and good chemical and thermal stability. Combining one or more of these can form a high-performance solid-state electrolyte layer, providing the battery with higher energy density and longer cycle life.

[0071] Binders connect and secure the electrolyte membrane, enhancing its mechanical strength and stability. Selecting one or more of these binders for compounding can optimize the membrane's film-forming and adhesion properties, allowing for better bonding with the electrode material. Binders also provide additional ion conduction pathways, further improving the ion conductivity of all-solid-state batteries.

[0072] The present application also provides a method for preparing a composite electrolyte membrane, comprising:

[0073] Step 1: mixing a polymer, a lithium salt, an additive and a first solvent to obtain slurry A;

[0074] Step 2: mixing the solid electrolyte, the binder and the second solvent to obtain slurry B;

[0075] Step 3: coating slurry B on the electrolyte membrane carrier and drying to obtain a solid electrolyte layer;

[0076] Step 4: constructing slurry A on the solid electrolyte layer and obtaining a composite electrolyte membrane after drying.

[0077] Optionally, in step 4, slurry A is constructed on the solid electrolyte layer by 3D printing or screen printing.

[0078] Optionally, the first solvent is selected from at least one of acetonitrile, anisole, chloroform, dichloroethane, and dimethylformamide;

[0079] The second solvent is selected from at least one of a benzene solvent, an aliphatic hydrocarbon solvent containing 4 or more carbon atoms, and an ester solvent.

[0080] It can be understood that the solvents of the solid electrolyte layer and the polymer layer are not shared, which can prevent the solid electrolyte of the solid electrolyte layer from being reacted, and the polymer material is used to improve the interface, reduce interfacial side reactions, increase the battery's cycle capacity retention rate, and reduce the interface impedance.

[0081] The present application is further described below through specific embodiments.

[0082] Example 1

[0083] S1: 2.7 g PEO, 0.9 g LiTFSI, 0.36 g CsNO3, and 40.5 g acetonitrile solvent were mixed and stirred until the solids dissolved to obtain a translucent slurry A;

[0084] S2: 3 g of Li6PS5Cl, 0.06 g of SEBS, and 3.06 g of xylene solvent were mixed and ball milled at 300 rpm for 30 min to obtain slurry B.

[0085] S3: Slurry B was coated on the support and vacuum dried at 60 °C for 12 h to obtain a 30 μm solid electrolyte layer;

[0086] S4: Slurry A was constructed on the surface of the solid electrolyte layer and vacuum dried at 75° C. for 8 h to obtain a composite electrolyte membrane, wherein the thickness of the polymer layer was 2 μm.

[0087] Example 2

[0088] Compared with Example 1, in Example 2, S1: 4 g PEG, 0.8 g LiFP6, 0.4 g RbPF6, and 40.5 g acetonitrile solvent were mixed and stirred until the solid was dissolved to obtain a translucent slurry A;

[0089] The thickness of the polymer layer in S4 is 1 μm, and the remaining steps are consistent with Example 1.

[0090] Example 3

[0091] Compared with Example 1, in Example 3, S1: 3 g of PMMA, 0.9 g of LiBF4, and 0.36 g of RbPF6 were mixed with 40.5 g of acetonitrile solvent and stirred until the solid was dissolved to obtain a translucent slurry A;

[0092] The thickness of the polymer layer in S4 is 3 μm, and the remaining steps are consistent with Example 1.

[0093] Example 4

[0094] Compared with Example 1, in Example 4, S1: 5 g PAN, 1 g LiFSI, 0.25 g CsNO3, and 40.5 g acetonitrile solvent were mixed and stirred until the solid was dissolved to obtain a translucent slurry A;

[0095] The thickness of the polymer layer in S4 is 4 μm. The remaining steps are the same as those in Example 1.

[0096] Example 5

[0097] Compared with Example 1, in S4 of Example 5, S1: 2 g of PEGDMA, 1 g of LiFSI, and 0.2 g of CsNO3 were mixed with 40.5 g of acetonitrile solvent, and stirred until the solid was dissolved to obtain a translucent slurry A;

[0098] The thickness of the polymer layer in S4 is 5 μm. The remaining steps are the same as those in Example 1.

[0099] Example 6

[0100] Compared with Example 1, S2 of Example 6 is as follows: 4 g of LATP, 0.1 g of SBR, and 3.06 g of xylene solvent are mixed, and the mixture is ball-milled at a rotation speed of 300 r / min for 30 min to obtain slurry B.

[0101] The thickness of the solid electrolyte layer in S3 is 70 μm. The remaining steps are the same as those in Example 1.

[0102] Example 7

[0103] Compared with Example 1, S2 of Example 7 is as follows: 5 g of Li3InCl6, 0.04 g of NBR, and 3.06 g of xylene solvent are mixed, and the mixture is ball-milled at a rotation speed of 300 r / min for 30 min to obtain slurry B.

[0104] The thickness of the solid electrolyte layer in S3 is 40 μm. The remaining steps are the same as those in Example 1.

[0105] Example 8

[0106] Compared with Example 1, the thickness of the solid electrolyte layer in S3 is 10 μm. The remaining steps are consistent with Example 1.

[0107] Example 9

[0108] Compared with Example 1, the thickness of the solid electrolyte layer in S3 is 50 μm. The remaining steps are consistent with Example 1.

[0109] Comparative Example 1

[0110] S1: 3 g of Li6PS5Cl, 0.06 g of SEBS, and 3.06 g of xylene solvent were mixed and ball-milled at a speed of 300 r / min for 30 min to obtain slurry C.

[0111] S2: Slurry C was coated on a support and vacuum dried at 60° C. for 12 h to obtain a 32 μm electrolyte membrane.

[0112] 100 all-solid-state batteries were prepared using the electrolyte membranes of Examples 1-11 and Comparative Example 1, and short-circuit rate tests, cycle number tests, and capacity retention rate tests were performed. The test results are shown in Table 1.

[0113] Table 1 Test results of Examples 1-11 and Comparative Example 1

[0114]

[0115] According to the above results, compared with the solid electrolyte membrane in Comparative Example 1, the all-solid-state battery prepared by the composite electrolyte membrane in Examples 1-9 has a reduced short-circuit rate and improved cycle performance. The reason is that a polymer layer is added to the solid electrolyte layer, and the additives in the polymer layer can promote the formation of a stable SEI film. At the same time, based on the self-healing electrostatic shielding mechanism, it promotes the uniform deposition of lithium and the protection of the lithium negative electrode, thereby increasing the number of cycles and capacity retention of the battery and reducing the short-circuit rate of the battery. In addition, the polymer material has good interface compatibility with the lithium metal negative electrode and the oxide positive electrode, and it is easy to form a stable interface with low impedance, and the elasticity of the polymer material can adapt to the volume change of the electrode and reduce the interface impedance.

[0116] As shown in Examples 1-5, the battery capacity retention rate of Example 1 is higher. The reason for this is that the battery performance is better when the polymer layer thickness is 2 μm. The thickness of the solid electrolyte layer has a similar effect on battery performance, and the battery performance is better when it is 50 μm.

[0117] The present application also provides an all-solid-state battery, comprising the composite electrolyte membrane, the positive electrode sheet 30 and the negative electrode sheet 40 as described in the first aspect and / or various possible embodiments of the first aspect. Figure 2 shown.

[0118] An embodiment of the present application also provides an electrical device, including the all-solid-state battery in the third aspect above.

[0119] Specifically, the electrical equipment may include, but is not limited to, electric vehicles, battery vehicles, mobile phones, tablet computers, laptop computers, electric toys, ships, spacecraft, etc. Electric toys may include fixed or mobile electric toys, such as game consoles, electric vehicle toys, electric ship toys, and electric airplane toys, and spacecraft may include airplanes, rockets, space shuttles, and spacecraft.

[0120] Finally, it should be noted that those skilled in the art will readily identify other embodiments of the present invention after considering the specification and practicing the invention disclosed herein. The present invention is intended to cover any variations, uses, or adaptations of the present invention that follow the general principles of the present invention and include common knowledge or customary techniques in the art not disclosed herein. The present invention is not limited to the precise structure described above and illustrated in the accompanying drawings, and various modifications and variations may be made without departing from the scope thereof. The scope of the present invention is limited solely by the appended claims.

Claims

1. A composite electrolyte membrane, characterized in that include: polymer layer and solid electrolyte layer; The polymer layer comprises a polymer, a lithium salt and an additive, and the thickness of the polymer layer is 1-5 μm; The solid electrolyte layer includes a solid electrolyte and a binder, and the thickness of the solid electrolyte layer is 10-70 μm.

2. The composite electrolyte membrane according to claim 1, characterized in that The mass ratio of the polymer, the lithium salt and the additive is 1:0.2-0.5:0.05-0.15; The mass ratio of the solid electrolyte to the binder is 1:0.005-0.

025.

3. The composite electrolyte membrane according to claim 1, characterized in that The additive is selected from at least one of cesium hexafluorophosphate, rubidium hexafluorophosphate, cesium nitrate, and rubidium nitrate.

4. The composite electrolyte membrane according to any one of claims 1 to 3, characterized in that The polymer is selected from at least one of polyethylene oxide, polyethylene glycol, polymethacrylate, polyethylene glycol dimethacrylate, and polyacrylonitrile; The lithium salt is selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium bis(oxalatoborate), lithium bis(trifluoromethylsulfonylimide), lithium bis(fluorosulfonylimide), and lithium bis(fluorooxalatoborate).

5. The composite electrolyte membrane according to any one of claims 1 to 3, characterized in that: The solid electrolyte is selected from at least one of a sulfide solid electrolyte, a halide solid electrolyte, and an oxide solid electrolyte; The binder is selected from at least one of polyvinylidene fluoride, polytetrafluoroethylene, polyacrylic acid, styrene-butadiene rubber, nitrile rubber, polyamide, polyvinyl alcohol, polyethyleneimine, polyimide, and hydrogenated styrene-butadiene block copolymer.

6. A method for preparing a composite electrolyte membrane, characterized in that: include: Mixing the polymer, lithium salt, additive and the first solvent to obtain slurry A; mixing the solid electrolyte, the binder and the second solvent to obtain slurry B; The slurry B is coated on the electrolyte membrane carrier, and dried to obtain a solid electrolyte layer; The slurry A is constructed on the solid electrolyte layer and dried to obtain the composite electrolyte membrane.

7. The preparation method according to claim 6, characterized in that The step of constructing the slurry A on the solid electrolyte layer comprises: The slurry A is constructed on the solid electrolyte layer by 3D printing or screen printing.

8. The preparation method according to claim 6 or 7, characterized in that The first solvent is selected from at least one of acetonitrile, anisole, chloroform, dichloroethane, and dimethylformamide; The second solvent is selected from at least one of a benzene solvent, an aliphatic hydrocarbon solvent containing 4 or more carbon atoms, and an ester solvent.

9. An all-solid-state battery, characterized in that: The invention comprises the composite electrolyte membrane, the positive electrode sheet and the negative electrode sheet according to any one of claims 1 to 5.

10. An electrical device, characterized in that: Including the all-solid-state battery according to claim 9.

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