Polymer electrolyte membrane, battery cell, battery device, and electric device

Abstract

A polymer electrolyte membrane, a battery cell, a battery device, and an electric device. The polymer electrolyte membrane comprises a first polymer electrolyte membrane and a second polymer electrolyte membrane which are stacked; the first polymer electrolyte membrane comprises a first polymer, a first plasticizer, and a first electrolyte salt, and the second polymer electrolyte membrane comprises a single-ion conducting polymer electrolyte. The polymer electrolyte membrane is used in the battery cell so that the battery cell has good cycle performance.

Description

Polymer electrolyte membrane, battery cell, battery device, and power utilization device

[0001] Cross-reference to Related Applications

[0002] This application claims priority to Chinese Patent Application No. 202411226258.3, filed on September 3, 2024, entitled “Polymer electrolyte membrane, battery cell, battery device, and power utilization device,” the entire contents of which are incorporated herein by reference. TECHNICAL FIELD

[0003] The present disclosure relates to a polymer electrolyte membrane, a battery cell, a battery device, and a power utilization device. BACKGROUND

[0004] Battery cells using polymer electrolyte membranes are not prone to combustion and explosion, have higher reliability, and also have higher energy density, but the service life of such battery cells is poor. SUMMARY

[0005] The present disclosure provides a polymer electrolyte membrane, a battery cell, a battery device, and a power utilization device, the polymer electrolyte membrane is applied in the battery cell, which can make the battery cell have good cycle performance.

[0006] In a first aspect, the present disclosure provides a polymer electrolyte membrane, the polymer electrolyte membrane comprises a first polymer electrolyte membrane and a second polymer electrolyte membrane stacked together, the first polymer electrolyte membrane comprises a first polymer, a first plasticizer, and a first electrolyte salt, and the second polymer electrolyte membrane comprises a single-ion conductor polymer electrolyte.

[0007] The second polymer electrolyte membrane comprises a single-ion conductor polymer electrolyte, which can increase the number of lithium ion migration and reduce the number of anion migration, thereby reducing the concentration polarization of the battery cell and slowing down dendrite growth. The first polymer electrolyte membrane comprises a first polymer, a first plasticizer, and a first electrolyte salt, the introduction of the first plasticizer can improve the ionic conductivity of the first polymer electrolyte membrane, and also improve the film-forming properties of the first polymer and enhance the mechanical properties of the first polymer electrolyte membrane. In addition, the first polymer electrolyte membrane also has good oxidation resistance and electrochemical stability. Therefore, the polymer electrolyte membrane of the present disclosure can not only slow down dendrite growth, but also has high ionic conductivity, as well as good mechanical properties, oxidation resistance, and electrochemical stability, which is applied in the battery cell, and can make the battery cell have good cycle performance.

[0008] In some embodiments, the first polymer comprises one or more of polyvinylidene fluoride, polymethyl methacrylate, polyamide, polyacrylonitrile, polyvinylidene fluoride-hexafluoropropylene, and derivatives thereof.

[0009] The first polymer is within the above range, which can make the first polymer electrolyte film have better electrochemical stability.

[0010] Optionally, the first polymer includes one or more of polyvinylidene fluoride-hexafluoropropylene and derivatives thereof.

[0011] In this way, the first polymer electrolyte film can have better electrochemical stability, and also have good film-forming properties and mechanical properties.

[0012] In some embodiments, the first plasticizer includes one or more of carbonate compounds, nitrile compounds, and ether compounds.

[0013] Optionally, the first plasticizer includes one or more of ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, vinylene carbonate, dipropyl carbonate, methyl ethyl carbonate, butanedinitrile, 1,3-dioxolane, ethylene glycol dimethyl ether, and tetraethylene glycol dimethyl ether.

[0014] The first plasticizer is within the above range, which can improve the ionic conductivity and flexibility of the first polymer electrolyte film.

[0015] In some embodiments, the first electrolyte salt includes one or more of lithium bisfluorosulfonylimide, lithium bistrifluoromethylsulfonylimide, lithium hexafluorophosphate, lithium tetrafluoroborate, lithium hexafluoroarsenate, lithium bisoxalate borate, lithium difluorooxalate borate, lithium difluorophosphate, lithium perchlorate, lithium triflate, lithium difluorodioxalate phosphate, and lithium tetrafluorooxalate phosphate.

[0016] Optionally, the first electrolyte salt includes one or more of lithium bisfluorosulfonylimide and lithium bistrifluoromethylsulfonylimide.

[0017] In some embodiments, the mass ratio of the first polymer to the first electrolyte salt is 0.14:1 to 20:1, and optionally 0.6:1 to 10:1.

[0018] The mass ratio of the first polymer to the first electrolyte salt is within the above range, which can make the battery cell have higher discharge capacity, good mechanical properties, good oxidation resistance, and good electrochemical stability.

[0019] In some embodiments, the mass ratio of the first polymer to the first plasticizer is 0.5:1 to 10:1, and optionally 1:1 to 3:1.

[0020] The mass ratio of the first polymer to the first plasticizer is within the above range, which can make the first polymer electrolyte film have good film-forming properties and mechanical properties.

[0021] In some embodiments, the first polymer electrolyte film further comprises first inorganic particles, the first inorganic particles comprising one or more of inorganic oxide particles, inorganic sulfide particles, inorganic nitride particles, inorganic halide particles.

[0022] In some embodiments, the first inorganic particles comprise one or more of silicon oxide, aluminum oxide, titanium oxide, zirconium oxide, silicon nitride, diatomite, montmorillonite, kaolin.

[0023] In some embodiments, the first inorganic particles have a particle size of 20 nm-300 nm.

[0024] In some embodiments, the single-ion conductor polymer electrolyte comprises a polymer backbone, an anion group or an anion acceptor consisting of a Lewis acid chemically bonded to the polymer backbone, and an alkali metal cation bonded to the anion group or anion acceptor.

[0025] In some embodiments, the polymer backbone comprises one or more of an acrylate structural unit, a styrene structural unit, a maleic anhydride structural unit, a vinylpyrrolidone structural unit, a vinyl alcohol structural unit, an ethylene oxide structural unit, an acrylonitrile structural unit, an ethylene glycol structural unit, an acrylamide structural unit.

[0026] In some embodiments, the anion group comprises one or more of a carboxylic acid anion CO2 - , a carboxylic acid anion-containing organic group, a sulfonic acid anion SO3 - , a sulfonic acid anion-containing organic group, a boronic acid anion BO4 - , a boronic acid anion-containing organic group, a boron trifluoride anion BF3 - , a boron trifluoride anion-containing organic group, a fluorosulfonylimide anion SO2N (-) SO2F, a sulfonylimide anion-containing organic group -SO2N (-) SO2-.

[0027] Optionally, the organic group in the carboxylic acid anion-containing organic group, the sulfonic acid anion-containing organic group, the boronic acid anion-containing organic group, the boron trifluoride anion-containing organic group, the sulfonylimide anion-containing organic group -SO2N (-) SO2- is an organic group having F atoms, a cyano group CN.

[0028] In some embodiments, the alkali metal cation comprises Li + , Na + , K + , Mg 2+ , Ba2+ Ca 2+ one or more of the group consisting of

[0029] In some embodiments, the single-ion conductor polymer electrolyte includes one or more of the structural units shown below, R1, R3, R5, R7, R9 each independently represents C1-C5 alkylene, C1-C5 haloalkylene, R2, R4, R6, R8, R 10 each independently represents a carboxylate anion CO2 - an organic group containing a carboxylate anion, a sulfonate anion SO3 - an organic group containing a sulfonate anion, a borate anion BO4 - an organic group containing a borate anion, a boron trifluoride anion BF3 - an organic group containing a boron trifluoride anion, a fluorosulfonylimide anion SO2N (-) SO2F, an organic group containing a fluorosulfonylimide anion -SO2N (-) SO2-, n is an integer between 1 and 10, m is an integer greater than or equal to 20.

[0030] In some embodiments, the second polymer electrolyte film further includes a second polymer, the second polymer including one or more of polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene, polyethylene oxide, polyethylene glycol, polyurea, polyurethane, polyamide, and respective derivatives thereof.

[0031] In some embodiments, the mass ratio of the single-ion conductor polymer electrolyte to the second polymer is 1.3:1 to 4:1.

[0032] In some embodiments, the second polymer electrolyte film further includes a second plasticizer, the second plasticizer including one or more of a carbonate compound, a nitrile compound, an ether compound.

[0033] In some embodiments, the second plasticizer includes one or more of ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, vinylene carbonate, dipropyl carbonate, methyl ethyl carbonate, butanedinitrile, 1,3-dioxolane, ethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether.

[0034] In some embodiments, the mass content of the second plasticizer in the second polymer electrolyte film is 1%-70%.

[0035] In some embodiments, the second polymer electrolyte film further includes a second inorganic particle, the second inorganic particle including one or more of an inorganic oxide particle, an inorganic sulfide particle, an inorganic nitride particle, an inorganic halide particle.

[0036] In some embodiments, the second inorganic particles include one or more of silicon oxide, aluminum oxide, titanium oxide, zirconium oxide, silicon nitride, diatomite, montmorillonite, kaolin.

[0037] In some embodiments, the particle size of the second inorganic particles is 20 nm-300 nm.

[0038] In some embodiments, the thickness of the first polymer electrolyte film is 10 μm-200 μm.

[0039] In some embodiments, the thickness of the second polymer electrolyte film is 10 μm-200 μm.

[0040] In a second aspect, the present disclosure provides a battery cell, which includes a positive electrode sheet, a negative electrode sheet, and the polymer electrolyte film of the first aspect, the polymer electrolyte film being located between the positive electrode sheet and the negative electrode sheet.

[0041] In some embodiments, the first polymer electrolyte film is close to the positive electrode sheet, and the second polymer electrolyte film is close to the negative electrode sheet.

[0042] The first polymer electrolyte film close to the positive electrode sheet can better exert its advantage of good electrochemical stability, and the second polymer electrolyte film close to the negative electrode sheet can better exert its advantages of reducing concentration polarization and slowing dendrite growth. Thus, the battery cell can have higher discharge capacity and better cycle performance.

[0043] In some embodiments, the positive electrode sheet includes one or more of lithium transition metal oxides and modified materials thereof, lithium-containing phosphates and modified materials thereof, lithium titanate, sulfur, selenium, and tellurium.

[0044] In some embodiments, the negative electrode sheet includes one or more of lithium, lithium alloy, natural graphite, artificial graphite, mesocarbon microbeads, soft carbon, hard carbon, silicon-based materials, tin-based materials, lithium titanate, and metal oxides.

[0045] In a third aspect, the present disclosure provides a battery device, which includes a plurality of the battery cells of the second aspect.

[0046] In a fourth aspect, the present disclosure provides a power utilization device, which includes the battery cell of the second aspect or the battery device of the third aspect. BRIEF DESCRIPTION OF DRAWINGS

[0047] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the following will briefly introduce the drawings needed to be used in the embodiments of the present disclosure. Obviously, the drawings described below only constitute some of the embodiments of the present disclosure, and for those skilled in the art, other drawings can also be obtained from the drawings without creative labor.

[0048] FIG. 1 shows a schematic diagram of a battery cell according to some embodiments of the present disclosure.

[0049] FIG. 2 shows a schematic diagram of an electric device according to some embodiments of the present disclosure.

[0050] In the drawings, the drawings are not necessarily drawn according to the actual proportions. DETAILED DESCRIPTION

[0051] Hereinafter, specific embodiments of the polymer electrolyte membrane, the battery cell, the battery device and the electric device of the present disclosure are specifically disclosed with appropriate reference to the drawings. However, there will be cases where unnecessary detailed description is omitted. For example, there are cases where detailed description of matters known well, repeated description of substantially the same structure are omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate understanding by those skilled in the art. In addition, the drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter recited in the claims.

[0052] The "range" disclosed in the present disclosure is defined in the form of a lower limit and an upper limit, a given range is defined by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundaries of a particular range. The range defined in this way can include or not include the end value, and can be arbitrarily combined, i.e., any lower limit can be combined with any upper limit to form a range. For example, if the ranges of 60-120 and 80-110 are listed for a particular parameter, it is understood that the ranges of 60-110 and 80-120 are also contemplated. In addition, if the minimum range values of 1 and 2 are listed, and if the maximum range values of 3, 4 and 5 are listed, the following ranges are all contemplated: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5. In the present disclosure, unless otherwise stated, the numerical range "a-b" represents a shorthand notation for any real combination of integers between a and b, where a and b are both real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" have been listed herein, and "0-5" is only a shorthand notation for these numerical combinations. In addition, when a parameter is stated to be ≥2 integers, it is equivalent to disclose that the parameter is, for example, integer 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0053] If there is no special indication, all the embodiments and optional embodiments of the present disclosure can be combined with each other to form new technical solutions, and such technical solutions should be considered to be included in the disclosure of the present disclosure.

[0054] If there is no special indication, all the technical features and optional technical features of the present disclosure can be combined with each other to form new technical solutions, and such technical solutions should be considered to be included in the disclosure of the present disclosure.

[0055] If there is no special indication, all the steps of the present disclosure can be performed in sequence or randomly, and the preferred is performed in sequence. For example, the method comprises steps (a) and (b), which means that the method can comprise steps (a) and (b) performed in sequence, or steps (b) and (a) performed in sequence. For example, the method also comprises step (c), which means that step (c) can be added to the method in any order, for example, the method can comprise steps (a), (b) and (c), or steps (a), (c) and (b), or steps (c), (a) and (b), etc.

[0056] If there is no special indication, in the present disclosure, the terms "first", "second", etc. are used to distinguish different objects, not to describe a specific order or primary and secondary relationship.

[0057] In the present disclosure, the terms "a plurality of" and "a plurality of" refer to two or more.

[0058] In the description of the embodiments of the present disclosure, if there is no special indication, the first feature is "on" or "under" the second feature, which can be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature can be above or above the second feature, or just indicate that the first feature is higher than the second feature in horizontal height. The first feature can be below or below the second feature, or just indicate that the first feature is lower than the second feature in horizontal height.

[0059] Unless otherwise specified, the test temperature of each parameter mentioned in the present disclosure is 25℃.

[0060] The battery cell mentioned in the embodiments of the present disclosure can realize the function of charging and discharging independently. The battery cell can be in the shape of a cylinder, a cuboid or other shapes, which are not limited in the embodiments of the present disclosure. As shown in FIG. 1, the battery cell 5 is a cuboid structure as an example.

[0061] The battery apparatus mentioned in the embodiments of the present disclosure can include one or more battery cell assemblies for providing voltage and capacity. The battery cell assembly can include a plurality of battery cells connected in series, in parallel, or in a mixed connection through a busbar component.

[0062] In some embodiments, the battery cell assembly is generally formed by arranging a plurality of battery cells.

[0063] As an example, the battery cell assembly can be a battery module formed by arranging and fixing a plurality of battery cells into one independent module. As an example, the battery module can be formed by bundling a plurality of battery cells with a cable tie.

[0064] In some embodiments, the battery apparatus can be a battery pack including a box and one or more battery cell assemblies housed in the box.

[0065] As an example, the battery cell assembly can be a battery module, which can be housed in the box by fixing the battery module in the box.

[0066] As an example, the battery cell assembly can also be housed in the box by directly fixing a plurality of battery cells in the box.

[0067] As an example, the box can include a first box and a second box. The first box and the second box are fastened so that an enclosed space is formed inside the box to accommodate the battery cell assembly. Here, the enclosed means covered or closed, which can be sealed or unsealed. The first box can be a top cover or a bottom plate.

[0068] As an example, the box can include a top cover, a frame, and a bottom plate. The top cover and the bottom plate are connected to the frame, respectively, so that an enclosed space is formed inside the box to accommodate the battery cell assembly.

[0069] In some embodiments, the box can be part of the chassis structure of the vehicle. For example, part of the box can be at least part of the floor of the vehicle, or part of the box can be at least part of the cross beam and the longitudinal beam of the vehicle.

[0070] The technical solutions described in the embodiments of the present disclosure are applicable to various power consumption devices using battery monomers and battery devices, for example, but not limited to, mobile devices (such as mobile phones, tablets, laptops, etc.), electric vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc. The battery monomers and battery devices are used to store or provide electric energy.

[0071] FIG. 2 is a schematic diagram of a power consumption device as an example. The power consumption device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc.

[0072] The battery monomer provided by the embodiments of the present disclosure includes an electrode assembly and an outer package, and the outer package can be used to package the electrode assembly. The outer package can be a hard shell, such as a hard plastic shell, an aluminum shell, a steel shell, etc. The outer package can also be a soft package, such as a bag-type soft package. The material of the soft package can be plastic, such as one or more of aluminum plastic film, polypropylene, polybutylene terephthalate (PBT), and polybutylene succinate (PBS).

[0073] Currently, the polymer electrolyte film used in the battery monomer mainly faces two problems: first, it is not resistant to high pressure at the positive electrode interface and is prone to overcharging; second, it cannot well block dendrites at the negative electrode interface. At present, a polymer electrolyte film that can simultaneously solve the above two problems has not been developed.

[0074] Based on this, the present disclosure provides a polymer electrolyte film, which is applied to a battery monomer and can make the battery monomer have good cycle performance.

[0075] The polymer electrolyte film of the present disclosure includes a first polymer electrolyte film and a second polymer electrolyte film stacked together, the first polymer electrolyte film includes a first polymer, a first plasticizer, and a first electrolyte salt, and the second polymer electrolyte film includes a single-ion conductor polymer electrolyte.

[0076] The conventional polymer electrolyte is a double-ion electrolyte. When the battery monomer is charged, the lithium ions and anions in the double-ion electrolyte simultaneously undergo electromigration under the influence of the electric field, in which the lithium ions migrate to the negative electrode side and the anions migrate to the positive electrode side. Ideally, the total migration amount of the anions and the cations is equal to the amount of lithium ions consumed by the reduction reaction at the negative electrode, so the amount of lithium ions consumed by the reduction at the negative electrode is greater than the amount of lithium ions migrated to the negative electrode side, thereby forming a concentration gradient at the negative electrode side and causing concentration polarization. Especially when the lithium ion concentration on the surface of the negative electrode decreases to zero, a large amount of dendrites will also be generated.

[0077] The second polymer electrolyte film of the present disclosure includes a single-ion conductor polymer electrolyte, which can increase the lithium ion transference number, reduce the anion transference number, thereby reducing the concentration polarization of the battery cell and slowing the dendrite growth.

[0078] The first polymer electrolyte film includes a first polymer, a first plasticizer and a first electrolyte salt. The introduction of the first plasticizer can improve the ionic conductivity of the first polymer electrolyte film, and also improve the film-forming properties of the first polymer and the mechanical properties of the first polymer electrolyte film. In addition, the first polymer electrolyte film also has good oxidation resistance and electrochemical stability.

[0079] Therefore, the polymer electrolyte film of the present disclosure can not only slow the dendrite growth, but also has high ionic conductivity, as well as good mechanical properties, oxidation resistance and electrochemical stability. When applied to a battery cell, the battery cell can have good cycle performance. In particular, the polymer electrolyte film of the present disclosure can make the high-voltage battery cell have good cycle performance.

[0080] In some embodiments, the first polymer can include one or more of polyvinylidene fluoride (PVDF), polymethyl methacrylate (PMMA), polyamide (PA), polyacrylonitrile (PAN), polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP) and derivatives thereof.

[0081] Derivatives refer to products derived from substitution of hydrogen atoms or atomic groups in a polymer with other atoms or atomic groups.

[0082] The first polymer is within the above range, which can make the first polymer electrolyte film have good electrochemical stability.

[0083] Alternatively, the first polymer can include one or more of polyvinylidene fluoride (PVDF), polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP) and derivatives thereof.

[0084] More alternatively, the first polymer can include one or more of polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP) and derivatives thereof.

[0085] In this way, the first polymer electrolyte film can not only have good electrochemical stability, but also have good film-forming properties and mechanical properties.

[0086] In some embodiments, the first plasticizer can include one or more of carbonate compounds, nitrile compounds and ether compounds.

[0087] The first plasticizer is within the above range, which can improve the ionic conductivity and flexibility of the first polymer electrolyte film.

[0088] Optionally, the first plasticizer can include one or more of ethylene carbonate (EC), propylene carbonate (PC), dimethyl carbonate (DMC), diethyl carbonate (DEC), vinylene carbonate (VC), dipropyl carbonate (DPC), ethyl methyl carbonate (EMC), succinonitrile (SN), 1,3-dioxolane (DOL), ethylene glycol dimethyl ether (DME), tetraethylene glycol dimethyl ether.

[0089] More optionally, the first plasticizer can include one or both of succinonitrile (SN) and tetraethylene glycol dimethyl ether. The above first plasticizer is not easy to volatilize and has good electrochemical stability.

[0090] In some embodiments, the first electrolyte salt can include one or more of lithium bisfluorosulfonylimide (LiFSI), lithium bis-trifluoromethanesulfonylimide (LiTFSI), lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium hexafluoroarsenate (LiAsF6), lithium bis(oxalato)borate (LiBOB), lithium difluoro(oxalato)borate (LiODFB), lithium difluorophosphate, lithium perchlorate (LiClO4), lithium triflate, lithium difluoro bis(oxalato)phosphate, lithium tetrafluoro bis(oxalato)phosphate.

[0091] Optionally, the first electrolyte salt can include one or both of lithium bisfluorosulfonylimide (LiFSI) and lithium bis-trifluoromethanesulfonylimide (LiTFSI). The above first electrolyte salt has good electrochemical stability, while its anion size is large, the dissociation degree is high, and it can also have high ionic conductivity.

[0092] In some embodiments, the mass ratio of the first polymer to the first electrolyte salt can be 0.14:1 to 20:1, for example, can be 0.14:1, 0.2:1, 0.4:1, 0.6:1, 0.8:1, 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 11:1, 12:1, 13:1, 14:1, 15:1, 16:1, 17:1, 18:1, 19:1, 20:1, or a range composed of any of the above values.

[0093] The mass ratio of the first polymer to the first electrolyte salt in the above range can make the battery cell have high discharge capacity, good mechanical properties, good oxidation resistance, and good electrochemical stability.

[0094] Optionally, the mass ratio of the first polymer to the first electrolyte salt can be 0.6:1 to 10:1, 0.6:1 to 8:1, 0.6:1 to 6:1, 0.6:1 to 4:1, 0.6:1 to 3:1, 1:1 to 10:1, 1:1 to 8:1, 1:1 to 6:1, 1:1 to 4:1, 1:1 to 3:1.

[0095] In some embodiments, the mass ratio of the first polymer to the first plasticizer can be 0.5:1 to 10:1, for example, can be 0.5:1, 0.6:1, 0.8:1, 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, or a range consisting of any of the foregoing.

[0096] The mass ratio of the first polymer to the first plasticizer in the above range can enable the first polymer electrolyte film to have good film-forming properties and mechanical properties.

[0097] Optionally, the mass ratio of the first polymer to the plasticizer can be 0.5:1 to 8:1, 0.5:1 to 6:1, 0.5:1 to 4:1, 0.8:1 to 8:1, 0.8:1 to 6:1, 0.8:1 to 4:1, 1:1 to 8:1, 1:1 to 6:1, 1:1 to 4:1, 1:1 to 3:1.

[0098] In some embodiments, the first polymer electrolyte film can further include first inorganic particles.

[0099] In some embodiments, the first inorganic particles can include one or more of inorganic oxide particles, inorganic sulfide particles, inorganic nitride particles, inorganic halide particles.

[0100] Optionally, the first inorganic particles can include one or more of silicon oxide, aluminum oxide, titanium oxide, zirconium oxide, silicon nitride, diatomite, montmorillonite, kaolin.

[0101] In some embodiments, the first inorganic particles can have a particle size of 20 nm-300 nm.

[0102] In some embodiments, the first polymer electrolyte film can have a thickness of 10 μm-200 μm, for example, can be 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm, 130 μm, 140 μm, 150 μm, 160 μm, 170 μm, 180 μm, 190 μm, 200 μm, or a range consisting of any of the foregoing. Optionally, the first polymer electrolyte film can have a thickness of 20 μm-100 μm, 40 μm-100 μm.

[0103] The thickness of the first polymer electrolyte film is within the above range, which can have good processability, and also can make the first polymer electrolyte film have suitable electronic resistance and ion transport path.

[0104] In some embodiments, the single-ion conductor polymer electrolyte can include a polymer backbone, an anion group chemically bonded to the polymer backbone or an anion acceptor composed of a Lewis acid, and an alkali metal cation combined with the anion group or the anion acceptor.

[0105] In some embodiments, the polymer backbone can include one or more of an acrylate structural unit, a styrene structural unit, a maleic anhydride structural unit, a vinylpyrrolidone structural unit, a vinyl alcohol structural unit, an ethylene oxide structural unit, an acrylonitrile structural unit, an ethylene glycol structural unit, and an acrylamide structural unit.

[0106] In some embodiments, the alkali metal cation can include one or more of Li + , Na + , K + , Mg 2+ , Ba 2+ , and Ca 2+ . Optionally, the alkali metal cation can include one or more of Li + , Na + , and K + . More optionally, the alkali metal cation can include Li + .

[0107] In some embodiments, the anion group can include one or more of a carboxylic acid anion CO2 - , an organic group containing a carboxylic acid anion, a sulfonic acid anion SO3 - , an organic group containing a sulfonic acid anion, a boronic acid anion BO4 - , an organic group containing a boronic acid anion, a boron trifluoride anion BF3 - , an organic group containing a boron trifluoride anion, a fluorosulfonylimide anion SO2N (-) SO2F, an organic group containing a sulfonylimide anion -SO2N (-) SO2-.

[0108] Optionally, the organic group in the organic group containing a carboxylic acid anion, the organic group containing a sulfonic acid anion, the organic group containing a boronic acid anion, the organic group containing a boron trifluoride anion, and the organic group containing a sulfonylimide anion -SO2N (-) SO2- can be an organic group having an F atom or a cyano group CN.

[0109] Optionally, the organic group in the organic group containing a sulfonylimide anion -SO2N(-) SO2- of the organic group can be -SO2N (-) SO2-CF3, -SO2N (-) SO2-CF2CF3, -SO2N (-) SO2-CF2CF2CF2CF3.

[0110] The hydrogen on the N atom of the anion is more acidic, which can further reduce the dissociation energy of the anion group and Li + , and can bring higher ion transference number and higher ionic conductivity.

[0111] In some embodiments, the single-ion conductor polymer electrolyte can include one or more of the structural units shown below, R1, R3, R5, R7, R9 each independently represents C1-C5 alkylene, C1-C5 haloalkylene, R2, R4, R6, R8, R 10 each independently represents carboxylate anion CO2 - , carboxylate anion-containing organic group, sulfonate anion SO3 - , sulfonate anion-containing organic group, borate anion BO4 - , borate anion-containing organic group, boron trifluoride anion BF3 - , boron trifluoride anion-containing organic group, fluorosulfonylimide anion SO2N (-) SO2F, sulfonylimide anion-containing organic group -SO2N (-) SO2- of the organic group, n is an integer between 1 and 10, and m is an integer greater than or equal to 20.

[0112] In some embodiments, the ion conductor polymer electrolyte can have a structural unit shown below. The hydrogen on the N atom of the anion is more acidic, which can further reduce the dissociation energy of the anion group and Li + , and can bring higher ion transference number and higher ionic conductivity.

[0113] In some embodiments, the second polymer electrolyte film can further include a second polymer, whereby the film-forming properties and mechanical properties of the second polymer electrolyte film can be improved.

[0114] Optionally, the second polymer can include one or more of polyvinylidene fluoride (PVDF), polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP), polyethylene oxide (PEO), polyethylene glycol (PEG), polyurea (PUA), polyurethane (PU), polyamide (PA), and respective derivatives thereof. Derivatives refer to products derived from substitution of hydrogen atoms or groups in the polymers with other atoms or groups.

[0115] In some embodiments, the mass ratio of the single-ion conductor polymer electrolyte to the second polymer can be 1.3:1 to 4:1, for example, can be 1.3:1, 1.4:1, 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1, 2:1, 2.1:1, 2.2:1, 2.3:1, 2.4:1, 2.5:1, 2.6:1, 2.7:1, 2.8:1, 2.9:1, 3:1, 3.1:1, 3.2:1, 3.3:1, 3.4:1, 3.5:1, 3.6:1, 3.7:1, 3.8:1, 3.9:1, 4:1, or a range consisting of any of the aforementioned values. Thereby, the film-forming property and mechanical property of the second polymer electrolyte film can be improved.

[0116] Alternatively, the mass ratio of the single-ion conductor polymer electrolyte to the second polymer can be 2:1 to 4:1.

[0117] In some embodiments, the second polymer electrolyte film can further include a second plasticizer. Thereby, the film-forming property of the second polymer electrolyte film can be improved.

[0118] Alternatively, the second plasticizer can include one or more of a carbonate compound, a nitrile compound, an ether compound.

[0119] More alternatively, the second plasticizer can include one or more of ethylene carbonate (EC), propylene carbonate (PC), dimethyl carbonate (DMC), diethyl carbonate (DEC), vinylene carbonate (VC), dipropyl carbonate (DPC), methyl ethyl carbonate (EMC), succinonitrile (SN), 1,3-dioxolane (DOL), ethylene glycol dimethyl ether (DME), tetraethylene glycol dimethyl ether.

[0120] In some embodiments, the mass content of the second plasticizer in the second polymer electrolyte film can be 1% to 70%, for example, can be 1%, 2%, 4%, 6%, 8%, 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24%, 26%, 28%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, or a range consisting of any of the aforementioned values.

[0121] Optionally, the mass content of the second plasticizer in the second polymer electrolyte film can be 10%-70%, 10%-60%, 10%-55%, 10%-50%, 10%-45%, 10%-40%, 16%-70%, 16%-60%, 16%-55%, 16%-50%, 16%-45%, 16%-40%, 20%-55%, 20%-50%, 20%-45%, 20%-40%, 24%-55%, 24%-50%, 24%-45%, 24%-40%.

[0122] The mass content of the second plasticizer in the above range can make the second polymer electrolyte film have good film-forming properties and mechanical properties.

[0123] In some embodiments, the second polymer electrolyte film can further include second inorganic particles.

[0124] In some embodiments, the second inorganic particles can include one or more of inorganic oxide particles, inorganic sulfide particles, inorganic nitride particles, and inorganic halide particles.

[0125] Optionally, the second inorganic particles can include one or more of silicon oxide, aluminum oxide, titanium oxide, zirconium oxide, silicon nitride, diatomite, montmorillonite, and kaolin.

[0126] In some embodiments, the particle size of the second inorganic particles can be 20 nm-300 nm.

[0127] In some embodiments, the thickness of the second polymer electrolyte film can be 10 μm-200 μm, for example, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm, 130 μm, 140 μm, 150 μm, 160 μm, 170 μm, 180 μm, 190 μm, 200 μm, or a range consisting of any of the above values. Optionally, the thickness of the second polymer electrolyte film can be 20 μm-100 μm, 40 μm-100 μm.

[0128] The thickness of the second polymer electrolyte film in the above range has good processing properties, can slow down dendrite growth, and make the second polymer electrolyte film have appropriate electronic resistance and ion transport paths.

[0129] The present disclosure also provides a method for preparing a polymer electrolyte film, which can prepare the above polymer electrolyte film.

[0130] The method for preparing the polymer electrolyte film comprises the following steps: providing a first polymer electrolyte film and a second polymer electrolyte film, and stacking the first polymer electrolyte film and the second polymer electrolyte film to obtain the polymer electrolyte film.

[0131] In some embodiments, the method for preparing the first polymer electrolyte film can comprise the following steps: mixing and stirring the first electrolyte salt, the first plasticizer, the first polymer and the first solvent uniformly, pouring the mixture into a mold, drying to remove the first solvent, and removing the mold to obtain the first polymer electrolyte film.

[0132] Optionally, the method for preparing the first polymer electrolyte film can comprise the following steps: mixing and stirring the first electrolyte salt and the first plasticizer to form a mixed solution; mixing and stirring the mixed solution, the first polymer and the first solvent uniformly, pouring the mixture into a mold, drying to remove the first solvent, and removing the mold to obtain the first polymer electrolyte film.

[0133] Optionally, the first solvent can comprise one or more of N-methyl pyrrolidone (NMP), acetonitrile, N,N-dimethylformamide, N,N-dimethylacetamide, tetrahydrofuran (THF), ethylene glycol, dimethyl sulfoxide, and water.

[0134] In some embodiments, the method for preparing the second polymer electrolyte film can comprise the following steps: mixing and stirring the single-ion conductor polymer electrolyte monomer, the second polymer, the initiator and the second solvent uniformly, pouring the mixture into a mold, then initiating polymerization to obtain a mixture film; adding the second plasticizer dropwise on the mixture film to make it fully infiltrate, removing the mold to obtain the second polymer electrolyte film.

[0135] The single-ion conductor polymer electrolyte monomer is polymerized to form a single-ion conductor polymer electrolyte.

[0136] Optionally, the initiator can comprise a thermal initiator and / or a photoinitiator.

[0137] Optionally, the initiator can comprise one or more of azobisisobutyronitrile, azobisisoheptyl nitrile, dimethyl azobisisobutyrate, benzoyl peroxide, cumene hydroperoxide, di-tert-butyl peroxide, tert-butyl benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxydicarbonate, ammonium persulfate, potassium persulfate, 2-hydroxy-2-methyl-1-phenylpropanone, alpha-amine alkyl phenone, diphenyl ketone, 1-hydroxycyclohexyl phenyl ketone, and benzophenone.

[0138] Optionally, the second solvent can comprise one or more of N-methyl pyrrolidone (NMP), acetonitrile, N,N-dimethylformamide, N,N-dimethylacetamide, tetrahydrofuran (THF), ethylene glycol, dimethyl sulfoxide, and water.

[0139] The battery cell provided by the embodiments of the present disclosure can be an ion battery cell, a metal battery cell, a negative electrode-free metal battery cell, for example, a lithium ion battery cell, a lithium metal battery cell, a negative electrode-free lithium metal battery cell, etc.

[0140] The battery cell provided by the embodiments of the present disclosure can be an ion battery cell, a metal battery cell, a negative electrode-free metal battery cell, for example, a lithium ion battery cell, a lithium metal battery cell, a negative electrode-free lithium metal battery cell, etc.

[0141] The negative electrode-free lithium metal battery cell generally refers to a battery cell that is not actively provided with a negative electrode active material layer on the negative electrode side during the manufacturing process of the battery cell, for example, a negative electrode active material layer formed of a carbon material is not provided at the negative electrode by a coating or deposition process during the manufacturing process of the battery cell. During the first charging, ions obtain electrons on the negative electrode side and deposit to form a metal phase on the surface of the negative electrode current collector. During discharging, the metal can be converted into metal ions to return to the positive electrode, realizing the cycle of charging and discharging. Compared with other battery cells, the negative electrode-free lithium metal battery cell can obtain higher energy density because it does not have a negative electrode active material layer. In some embodiments, in order to improve the performance of the battery cell, some substances that can be used as negative electrode active materials, such as carbon materials, can also be provided on the negative electrode side of the negative electrode-free lithium metal battery cell. Although these substances have a certain capacity, because their content is small and they are not used as the main negative electrode active material in the battery cell, the battery cell thus constituted can still be regarded as a negative electrode-free lithium metal battery cell. The CB value of the negative electrode-free lithium metal battery cell is usually very small, for example, in some embodiments, the CB value of the negative electrode-free lithium metal battery cell can be less than or equal to 0.1. The CB value is the capacity per unit area of the negative electrode in the battery cell divided by the capacity per unit area of the positive electrode. Because the negative electrode-free lithium metal battery cell does not contain or contains only a small amount of negative electrode active material, the capacity per unit area of the negative electrode is small, and thus the CB value is very small, for example, usually less than or equal to 0.1.

[0142] In some embodiments, the first polymer electrolyte membrane is close to the positive electrode sheet, and the second polymer electrolyte membrane is close to the negative electrode sheet.

[0143] The first polymer electrolyte membrane close to the positive electrode sheet can better exert its advantage of good electrochemical stability, and the second polymer electrolyte membrane close to the negative electrode sheet can better exert its advantage of reducing concentration polarization and slowing down dendrite growth. Thus, the battery cell can have higher discharge capacity and better cycle performance.

[0144] [Positive electrode sheet]

[0145] In some embodiments, the positive electrode sheet can include a positive electrode current collector and a positive electrode film layer on at least one surface of the positive electrode current collector, the positive electrode film layer including a positive electrode active material. The positive electrode current collector has two surfaces opposite in the thickness direction of the positive electrode current collector, and the positive electrode film layer is disposed on either one or both of the two opposite surfaces of the positive electrode current collector.

[0146] In some embodiments, the positive electrode active material can include one or more of lithium transition metal oxides and modified materials thereof, lithium-containing phosphates and modified materials thereof, lithium titanate, sulfur, selenium, tellurium.

[0147] Optionally, examples of the lithium transition metal oxide can include, but are not limited to, one or more of lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, lithium-rich manganese-based materials.

[0148] Optionally, examples of the lithium-containing phosphate can include, but are not limited to, one or more of lithium iron phosphate, a composite of lithium iron phosphate and carbon, lithium manganese phosphate, a composite of lithium manganese phosphate and carbon, lithium manganese iron phosphate, a composite of lithium manganese iron phosphate and carbon.

[0149] In some embodiments, in order to further improve the energy density of the battery cell, the positive electrode active material can include one or more of lithium transition metal oxides and modified materials thereof of the general formula Li a Ni b Co c M d O e A f 0.8≤a≤1.2, 0.5≤b<1, 0<c<1, 0<d<1, 1≤e≤2, 0≤f≤1, M can include one or more of Mn, Al, Zr, Zn, Cu, Cr, Mg, Fe, V, Ti and B, and A can include one or more of N, F, S and Cl.

[0150] As an example, the positive electrode active material can include, but is not limited to, LiCoO2, LiNiO2, LiMnO2, LiMn2O4, LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2(referred to as NCM333), LiNi 0.5 Co 0.2 Mn 0.3 O2(referred to as NCM523), LiNi 0.5 Co 0.25 Mn 0.25 O2(referred to as NCM211), LiNi 0.6 Co 0.2 Mn 0.2O2(simplified as NCM622), LiNi 0.8 Co 0.1 Mn 0.1 O2(simplified as NCM811), LiNi 0.83 Mn 0.08 Co 0.07 O2(simplified as Ni83), LiNi 0.90 Mn 0.05 Co 0.05 O2(simplified as Ni90), LiNi 0.94 Mn 0.03 Co 0.03 O2(simplified as Ni94), LiNi 0.96 Co 0.02 Mn 0.02 O2(simplified as Ni96), LiNi 0.80 Co 0.15 Al 0.05 O2, LiFePO4, LiMnPO4, and their respective modified materials.

[0151] The battery cell will be accompanied by Li de-intercalation and consumption during charging and discharging, and the molar content of Li is different when the battery cell is discharged to different states. In the enumeration of the positive electrode active material in the present disclosure, the molar content of Li is the initial state of the material, i.e., the state before feeding, and the positive electrode active material is applied to the battery cell. After charging and discharging cycle, the molar content of Li will change. In the enumeration of the positive electrode active material in the present disclosure, the molar content of O is only the theoretical state value, and the release of oxygen from the lattice will cause the molar content of O to change, and the actual molar content of O will also appear to float.

[0152] The modified material of each of the above positive electrode active materials can be a doping modification and / or a surface coating modification of the positive electrode active material.

[0153] In some embodiments, the positive electrode film layer can further include a positive electrode binder, which can include but is not limited to one or more of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, fluorine-containing acrylic ester resin.

[0154] In some embodiments, the positive electrode film layer can further include a positive electrode conductive agent, which can include but is not limited to one or more of super conductive carbon, acetylene black, carbon black, ketjen black, carbon dots, carbon nanotubes, graphene, carbon nanofibers, vapor grown carbon fiber (VGCF).

[0155] In some embodiments, the positive current collector can be a metal foil or a composite current collector. As an example of a metal foil, carbon-coated aluminum foil, aluminum foil, nickel foil, titanium foil can be employed. The composite current collector can include a polymer material base layer and a metal material layer formed on at least one surface of the polymer material base layer. As an example, the metal material can include, but is not limited to, one or more of aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy. As an example, the polymer material base layer can include, but is not limited to, one or more of polypropylene, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), and polyethylene.

[0156] [Anode sheet]

[0157] In some embodiments, the anode sheet can include one or more of lithium, lithium alloy, natural graphite, artificial graphite, mesocarbon microbead, soft carbon, hard carbon, silicon-based material, tin-based material, lithium titanate, metal oxide.

[0158] Optionally, the mass fraction of lithium element in the lithium alloy can be above 90%.

[0159] Optionally, the other elements in the lithium alloy can include, but are not limited to, one or more of In, Mg, Al, Zn, Sn, Ag, Au, Ga, Pt, Fe.

[0160] Optionally, the lithium alloy can include, but is not limited to, InLi alloy, Li-Mg alloy, Li-Al alloy, Li-Zn alloy, Li-Fe alloy, etc.

[0161] Optionally, the silicon-based material can include, but is not limited to, one or more of elemental silicon, silicon oxide, silicon-carbon composite material, silicon-nitrogen composite, and silicon alloy material.

[0162] Optionally, the tin-based material can include, but is not limited to, one or more of elemental tin, tin oxide, and tin alloy material.

[0163] Optionally, the metal oxide can include, but is not limited to, one or more of TiO2, MoO2, In2O3, Al2O3, Cu2O, VO2, Ga2O3, Sb2O5, Bi2O5.

[0164] In some embodiments, the anode sheet can be a lithium sheet or a lithium alloy sheet.

[0165] In some embodiments, the anode sheet can include an anode current collector and a lithium metal layer located on at least one surface of the anode current collector. The anode current collector has two surfaces opposite in the thickness direction of itself, and the lithium metal layer is disposed on any one or both of the two opposite surfaces of the anode current collector.

[0166] In some embodiments, the lithium-based metal layer can be lithium or a lithium alloy.

[0167] In some embodiments, the negative electrode sheet can include a negative electrode current collector and a negative electrode film layer on at least one surface of the negative electrode current collector, the negative electrode film layer including a negative electrode active material. The negative electrode current collector has two surfaces opposite in the thickness direction of the negative electrode current collector, and the negative electrode film layer is disposed on either one or both of the two opposite surfaces of the negative electrode current collector.

[0168] In some embodiments, the negative electrode active material can include, but is not limited to, one or more of natural graphite, artificial graphite, meso-phase carbon microbeads, soft carbon, hard carbon, silicon-based materials, tin-based materials, lithium titanate, and metal oxides.

[0169] In some embodiments, the negative electrode film layer can further include a negative electrode binder, which can include, but is not limited to, one or more of styrene butadiene rubber (SBR), water-soluble unsaturated resin SR-1B, polyacrylic acid, polymethacrylic acid, sodium polyacrylate, polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), carboxymethyl chitosan (CMCS), methyl vinyl silicone rubber, nitrile rubber (NBR), hydrogenated nitrile rubber (HNBR), thermoplastic styrene butadiene rubber (SBS), isoprene rubber, butadiene rubber (BR), ethyl cellulose, fluororubber, and acrylate rubber.

[0170] In some embodiments, the negative electrode film layer can further include a negative electrode conductive agent, which can include, but is not limited to, one or more of super conductive carbon, acetylene black, carbon black, ketjen black, carbon dots, carbon nanotubes, graphene, carbon nanofibers, and vapor grown carbon fiber (VGCF).

[0171] In some embodiments, the negative electrode sheet can include a negative electrode current collector, but does not include a lithium-based metal layer or a negative electrode film layer. During the cycle charging and discharging of the negative electrode-free lithium metal battery cell, lithium from the positive electrode will be deposited and peeled off in the form of lithium metal on the negative electrode side. Optionally, a lithium-philic layer can be further disposed on the surface of the negative electrode current collector layer.

[0172] In some embodiments, the negative current collector can be a metal foil, a three-dimensional porous current collector, or a composite current collector. As an example of a metal foil, a copper foil, a copper alloy foil, a nickel foil, a nickel alloy foil, an aluminum foil, or an aluminum alloy foil can be used. As an example of a three-dimensional porous current collector, a copper mesh, a nickel mesh, an aluminum mesh, a copper foam, a nickel foam, or an aluminum foam can be used. The composite current collector can include a polymer material base layer and a metal material layer formed on at least one surface of the polymer material base layer. As an example, the metal material can include, but is not limited to, one or more of copper, copper alloy, aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy. As an example, the polymer material base layer can include, but is not limited to, one or more of polypropylene, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene, and polyethylene.

[0173] Methods for preparing battery cells are known.

[0174] In some embodiments, the positive electrode sheet, the polymer electrolyte membrane, and the negative electrode sheet can be assembled to obtain an electrode assembly, and the electrode assembly can be placed in an outer package to obtain a battery cell.

[0175] Embodiments

[0176] The following examples more specifically describe the present disclosure, which are merely illustrative and not limiting, as various modifications and changes can be apparent to those skilled in the art within the scope of the present disclosure. Unless otherwise stated, all parts, percentages, and ratios reported in the following examples are on a mass basis, and all reagents used in the examples are commercially available or synthesized according to conventional methods and used as received without further purification, and the instruments used in the examples are commercially available.

[0177] Example 1

[0178] Preparation of the first polymer electrolyte membrane

[0179] Lithium bis-trifluoromethanesulfonimide (LiTFSI) and butanedinitrile (SN) were mixed at a mass ratio of 2:3 for 2 hours or more to form a mixed solution; the mixed solution, polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP), and tetrahydrofuran (THF) were mixed at a mass ratio of 5:3:16 until uniform; the obtained mixed solution was then poured into a polytetrafluoroethylene template and left to stand in a fume hood in a dry room for 24 hours or more until the THF was completely volatilized, and the template was removed to obtain a first polymer electrolyte membrane with a thickness of 60 μm.

[0180] Preparation of the second polymer electrolyte membrane

[0181] Dissolve 19.5 g of p-styrene sulfonyl chloride, 15.0 g of CF3SO2NHK and 0.21 g of 4-tert-butyl catechol in 100 ml of acetonitrile and stir at 0°C, then add 7.6 g of pyridine dropwise under a nitrogen atmosphere, heat the mixture at 65°C for 48 h, then remove the solvent under vacuum; dissolve the obtained product in 100 ml of deionized water, add 6.6 g of K2CO3, neutralize by stirring at 0°C, then remove the volatile matter under negative pressure at 50°C, then dry the brown product in an oven at 70°C for 10 h to obtain substance A; mix substance A with LiClO4 in a molar ratio of 1:1 in acetonitrile to obtain a lithium monomer of styrene sulfonyl (trifluoromethylsulfonyl) imide.

[0182] Mix the lithium monomer of styrene sulfonyl (trifluoromethylsulfonyl) imide with polyvinylidene hexafluoropropylene (PVDF-HFP) in a mass ratio of 8:2 in N-methyl pyrrolidone (NMP), then add azobisisobutyronitrile (AIBN) as a thermal initiator, the mass of AIBN is 2% of the mass of the monomer, stir together for 2 h, then pour the mixture into a polytetrafluoroethylene template and heat in a vacuum oven at 80°C until the NMP is completely volatilized to form a mixture film with a thickness of 60 μm; mix ethylene carbonate and propylene carbonate in a volume ratio of 1:1 as a plasticizer; add the plasticizer dropwise on the mixture film in a mass ratio of 5:10 to make it completely infiltrate, remove the template to obtain a second polymer electrolyte film.

[0183] The single-ion conductor polymer electrolyte in the second polymer electrolyte film has a structural unit as shown below.

[0184] Preparation of lithium metal battery monomer

[0185] Dissolve 19.5 g of p-styrene sulfonyl chloride, 15.0 g of CF3SO2NHK and 0.21 g of 4-tert-butyl catechol in 100 ml of acetonitrile and stir at 0°C, then add 7.6 g of pyridine dropwise under a nitrogen atmosphere, heat the mixture at 65°C for 48 h, then remove the solvent under vacuum; dissolve the obtained product in 100 ml of deionized water, add 6.6 g of K2CO3, neutralize by stirring at 0°C, then remove the volatile matter under negative pressure at 50°C, then dry the brown product in an oven at 70°C for 10 h to obtain substance A; mix substance A with LiClO4 in a molar ratio of 1:1 in acetonitrile to obtain a lithium monomer of styrene sulfonyl (trifluoromethylsulfonyl) imide. 0.8 Co 0.1 Mn 0.1 O2, a positive electrode binder polyvinylidene fluoride (PVDF), and a positive electrode conductive agent acetylene black are mixed in a mass ratio of 98:1:1, then N-methyl pyrrolidone is added to stir to form a uniform positive electrode slurry; the positive electrode slurry is uniformly coated on both surfaces of an aluminum foil current collector, so that the loading amount of the positive electrode active material is 25 mg / cm 2 , then go through the steps of drying and cold pressing, and cut it into a rectangle of 40 mm*50 mm as a positive electrode sheet.

[0186] A lithium foil with a thickness of 50 μm is compounded with a copper foil by rolling, then cut into a rectangle of 41 mm*51 mm as a negative electrode sheet.

[0187] A piece of positive electrode sheet and a piece of negative electrode sheet were matched, and a polymer electrolyte film was used for isolation in the middle, and the stacking order was positive electrode sheet-first polymer electrolyte film-second polymer electrolyte film-negative electrode sheet; then tab welding was performed, and then it was wrapped in an aluminum plastic film outer packaging bag for packaging, and then hot pressed at 70°C for 180s, and then stood at 25°C for 6h, to obtain a lithium metal battery monomer, and the rated capacity of the lithium metal battery monomer was 70mAh.

[0188] Comparative Example 1

[0189] The preparation method of the lithium metal battery monomer was the same as that of Example 1, except for the following differences.

[0190] Preparation of a lithium metal battery monomer

[0191] A piece of positive electrode sheet and a piece of negative electrode sheet were matched, and a first polymer electrolyte film was used for isolation in the middle, and the stacking order was positive electrode sheet-first polymer electrolyte film-negative electrode sheet; then tab welding was performed, and then it was wrapped in an aluminum plastic film outer packaging bag for packaging, and then hot pressed at 70°C for 180s, and then stood at 25°C for 6h, to obtain a lithium metal battery monomer, and the rated capacity of the lithium metal battery monomer was 70mAh.

[0192] Comparative Example 2

[0193] The preparation method of the lithium metal battery monomer was the same as that of Example 1, except for the following differences.

[0194] Preparation of a lithium metal battery monomer

[0195] A piece of positive electrode sheet and a piece of negative electrode sheet were matched, and a second polymer electrolyte film was used for isolation in the middle, and the stacking order was positive electrode sheet-second polymer electrolyte film-negative electrode sheet; then tab welding was performed, and then it was wrapped in an aluminum plastic film outer packaging bag for packaging, and then hot pressed at 70°C for 180s, and then stood at 25°C for 6h, to obtain a lithium metal battery monomer, and the rated capacity of the lithium metal battery monomer was 70mAh.

[0196] Comparative Example 3

[0197] Preparation of a polymer electrolyte film

[0198] Lithium bis-trifluoromethylsulfonylimide (LiTFSI) was dissolved in acetonitrile, and then polyethylene oxide (PEO) was added, and the mass ratio of PEO to LiTFSI was 2:13; the mixed solution was stirred for 24h, and then the solvent was volatilized at 60°C to obtain a PEO / LiTFSI polymer electrolyte film.

[0199] Preparation of a lithium metal battery monomer

[0200] The positive electrode active material LiNi 0.8Co 0.1 Mn 0.1 O2, positive electrode binder polyvinylidene fluoride (PVDF), positive electrode conductive agent acetylene black were mixed in a mass ratio of 98:1:1, and then N-methyl pyrrolidone was added for stirring to form a uniform positive electrode slurry; the positive electrode slurry was uniformly coated on both surfaces of an aluminum foil current collector, so that the loading of the positive electrode active material was 25 mg / cm 2 , and then it was subjected to a drying and cold pressing step, and was slit to form a 40 mm*50 mm rectangle as a positive electrode sheet.

[0201] A lithium foil with a thickness of 50 μm was compounded with a copper foil by rolling, and then was cut into a 41 mm*51 mm rectangle as a negative electrode sheet.

[0202] One positive electrode sheet and one negative electrode sheet were matched, with a PEO / LiTFSI polymer electrolyte film in between for insulation, in the order of positive electrode sheet-PEO / LiTFSI polymer electrolyte film-negative electrode sheet; then tab welding was performed, and then it was packaged in an aluminum-plastic film outer packaging bag for packaging, and then was hot-pressed at 70°C for 180 s, and then was left to stand at 25°C for 6 h, to obtain a lithium metal battery monomer, with a rated capacity of 70 mAh.

[0203] Performance test

[0204] (1) Ion transference number test

[0205] A lithium metal sheet, a second polymer electrolyte film, and a lithium metal sheet were stacked in turn, and then tab welding was performed, and then it was packaged in an aluminum-plastic film outer packaging bag for packaging, and then was hot-pressed at 70°C for 180 s, and then was left to stand at 25°C for 6 h, to obtain a lithium-lithium symmetric battery. The lithium-lithium symmetric battery was subjected to EIS test by an electrochemical workstation, and the initial interfacial impedance R0 (i.e. the sum of R SEI and R ct ) of the battery was measured, and then a polarization voltage AV of 10 mV was applied to the lithium-lithium symmetric battery by the electrochemical workstation, and the initial current I0 was recorded, and after a period of time when the current was stable, the current Is at that time was recorded, and finally the interfacial resistance R s (i.e. the sum of R SEI and R ct ) of the battery after polarization was measured again by EIS test, and the lithium ion transference number was calculated.

[0206] (2) Cycle performance test

[0207] The lithium metal battery cell was subjected to a cycle performance test at 25°C with 0.1C (7 mA) charging and 0.5C (35 mA) discharging, respectively. Specifically, the lithium metal battery cell was charged at a rate of 0.1C to 4.3V, then charged at a constant voltage until the current decayed to 0.05C; then discharged at a rate of 0.5C to a voltage of 2.8V to obtain the first cycle discharge capacity; and then the above steps were repeated for the cycle charging and discharging.

[0208] Table 1

[0209] The lithium ion transference number of the second polymer electrolyte film prepared in Example 1 was 0.87.

[0210] From the above test results, it can be seen that the polymer electrolyte film of the present disclosure can make the high-voltage lithium metal battery cell have good cycle performance.

[0211] Example 2

[0212] The preparation method of the lithium metal battery cell was the same as that of Example 1, except for the following differences.

[0213] Preparation of the first polymer electrolyte film

[0214] Lithium bis-trifluoromethylsulfonylimide (LiTFSI) and butanedinitrile (SN) were mixed at a mass ratio of 3:3 for stirring for more than 2h to form a mixed solution; the mixed solution, polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP), and tetrahydrofuran (THF) were mixed at a mass ratio of 6:3:16 for uniform stirring; the obtained mixed solution was then poured into a polytetrafluoroethylene template, and was left to stand in a drying room fume hood for more than 24h until the THF was completely volatilized, and the template was removed to obtain a first polymer electrolyte film with a thickness of 60μm.

[0215] Example 3

[0216] The preparation method of the lithium metal battery cell was the same as that of Example 1, except for the following differences.

[0217] Preparation of the first polymer electrolyte film

[0218] Lithium bis-trifluoromethylsulfonylimide (LiTFSI) and butanedinitrile (SN) were mixed at a mass ratio of 4:3 for stirring for more than 2h to form a mixed solution; the mixed solution, polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP), and tetrahydrofuran (THF) were mixed at a mass ratio of 7:3:16 for uniform stirring; the obtained mixed solution was then poured into a polytetrafluoroethylene template, and was left to stand in a drying room fume hood for more than 24h until the THF was completely volatilized, and the template was removed to obtain a first polymer electrolyte film with a thickness of 60μm.

[0219] Example 4

[0220] The preparation method of the lithium metal battery cell is the same as that of Example 1, except for the following differences.

[0221] Preparation of the first polymer electrolyte film

[0222] Lithium bis-trifluoromethylsulfonylimide (LiTFSI), butanedinitrile (SN) were mixed with a mass ratio of 1:3 for stirring for more than 2 h to form a mixed solution; the mixed solution, polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP), and tetrahydrofuran (THF) were mixed with a mass ratio of 4:4:16 for uniform stirring; the obtained mixed solution was then poured into a polytetrafluoroethylene template, and was left to stand in a dry house fume hood for more than 24 h until the THF was completely volatilized, and the template was removed, to obtain a first polymer electrolyte film with a thickness of 60 μm.

[0223] Example 5

[0224] The preparation method of the lithium metal battery cell is the same as that of Example 1, except for the following differences.

[0225] Preparation of the first polymer electrolyte film

[0226] Lithium bis-trifluoromethylsulfonylimide (LiTFSI), butanedinitrile (SN) were mixed with a mass ratio of 1:3 for stirring for more than 2 h to form a mixed solution; the mixed solution, polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP), and tetrahydrofuran (THF) were mixed with a mass ratio of 4:4:16 for uniform stirring; the obtained mixed solution was then poured into a polytetrafluoroethylene template, and was left to stand in a dry house fume hood for more than 24 h until the THF was completely volatilized, and the template was removed, to obtain a first polymer electrolyte film with a thickness of 60 μm.

[0227] Example 6

[0228] The preparation method of the lithium metal battery cell is the same as that of Example 1, except for the following differences.

[0229] Preparation of the first polymer electrolyte film

[0230] Lithium bis-trifluoromethylsulfonylimide (LiTFSI), butanedinitrile (SN) were mixed with a mass ratio of 2:1 for stirring for more than 2 h to form a mixed solution; the mixed solution, polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP), and tetrahydrofuran (THF) were mixed with a mass ratio of 3:3:16 for uniform stirring; the obtained mixed solution was then poured into a polytetrafluoroethylene template, and was left to stand in a dry house fume hood for more than 24 h until the THF was completely volatilized, and the template was removed, to obtain a first polymer electrolyte film with a thickness of 60 μm.

[0231] Example 7

[0232] The preparation method of the lithium metal battery cell is the same as that of Example 1, except for the following differences.

[0233] Preparation of the first polymer electrolyte film

[0234] Lithium bis-trifluoromethylsulfonylimide (LiTFSI) and butanedinitrile (SN) were mixed at a mass ratio of 2:4 for stirring for 2 h or more to form a mixed solution; the mixed solution, polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP), and tetrahydrofuran (THF) were mixed at a mass ratio of 6:3:16 for uniform stirring; the obtained mixed solution was then poured into a polytetrafluoroethylene template, and was left to stand in a fume hood in a dry room for 24 h or more until the THF was completely volatilized, and the template was removed, to obtain a first polymer electrolyte film with a thickness of 60 pm.

[0235] Example 8

[0236] The preparation method of the lithium metal battery cell is the same as that of Example 1, except for the following differences.

[0237] Preparation of the first polymer electrolyte film

[0238] Lithium bis-trifluoromethylsulfonylimide (LiTFSI) and butanedinitrile (SN) were mixed at a mass ratio of 4:1 for stirring for 2 h or more to form a mixed solution; the mixed solution, polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP), and tetrahydrofuran (THF) were mixed at a mass ratio of 5:6:16 for uniform stirring; the obtained mixed solution was then poured into a polytetrafluoroethylene template, and was left to stand in a fume hood in a dry room for 24 h or more until the THF was completely volatilized, and the template was removed, to obtain a first polymer electrolyte film with a thickness of 60 pm.

[0239] Example 9

[0240] The preparation method of the lithium metal battery cell is the same as that of Example 1, except for the following differences.

[0241] Preparation of the first polymer electrolyte film

[0242] Lithium bis-trifluoromethylsulfonylimide (LiTFSI) and tetraglyme were mixed at a mass ratio of 2:3 for stirring for 2 h or more to form a mixed solution; the mixed solution, polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP), and tetrahydrofuran (THF) were mixed at a mass ratio of 5:3:16 for uniform stirring; the obtained mixed solution was then poured into a polytetrafluoroethylene template, and was left to stand in a fume hood in a dry room for 24 h or more until the THF was completely volatilized, and the template was removed, to obtain a first polymer electrolyte film with a thickness of 60 pm.

[0243] Table 2

[0244] From the above test results, it can be seen that by further adjusting the composition of the first polymer electrolyte film, the high-voltage lithium metal battery cell can have better cycle performance.

[0245] Example 10

[0246] The preparation method of the lithium metal battery cell is the same as that of Example 1, except for the following differences.

[0247] Preparation of the second polymer electrolyte film

[0248] 19.5 g of p-styrene sulfonic chloride, 15.0 g of CF3SO2NHK, and 0.21 g of 4-tert-butyl catechol were dissolved in 100 ml of acetonitrile and stirred at 0°C, followed by dropwise addition of 7.6 g of pyridine under a nitrogen atmosphere, and the mixture was heated at 65°C for 48 h, and then the solvent was removed under vacuum; the obtained product was dissolved in 100 ml of deionized water, 6.6 g of K2CO3 was added, and the mixture was stirred at 0°C for neutralization, followed by removal of volatile substances under negative pressure at 50°C, and then the brown product was dried in an oven at 70°C for 10 h to obtain substance A; substance A was mixed with LiClO4 in a molar ratio of 1:1 in acetonitrile to obtain a lithium styrene sulfonate (trifluoromethyl sulfonate) imide monomer.

[0249] The lithium styrene sulfonate (trifluoromethyl sulfonate) imide monomer was mixed with polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP) in a mass ratio of 8:2 in N-methyl pyrrolidone (NMP), and azobisisobutyronitrile (AIBN) was added as a thermal initiator, with the mass of AIBN being 2% of the mass of the monomer, and the mixture was stirred for 2 h, followed by pouring the mixture into a polytetrafluoroethylene template and heating in a vacuum oven at 80°C until the NMP was completely volatilized, forming a mixed film with a thickness of 60 μm; ethylene carbonate and propylene carbonate were mixed in a volume ratio of 1:1 as a plasticizer; the plasticizer was added to the mixed film in a mass ratio of 6:10 to completely infiltrate the mixed film, and the template was removed to obtain a second polymer electrolyte film.

[0250] Example 11

[0251] The preparation method of the lithium metal battery cell is the same as that of Example 1, except for the following differences.

[0252] Preparation of the second polymer electrolyte film

[0253] Styrene sulfonic acid (trifluoromethylsulfonyl) imide lithium monomer was mixed with polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP) in a mass ratio of 8:2 in N-methyl pyrrolidone (NMP), and azobisisobutyronitrile (AIBN) was added as a thermal initiator, with the mass of AIBN being 2% of the mass of the monomer, and the mixture was stirred for 2 h, then the mixture was poured into a polytetrafluoroethylene template and heated in a vacuum oven at 80°C until the NMP was completely volatilized, forming a mixture film with a thickness of 60 μm; ethylene carbonate and propylene carbonate were mixed in a volume ratio of 1:1 as a plasticizer; the plasticizer was added to the mixture film in a mass ratio of 7:10 to completely infiltrate the mixture film, and the template was removed to obtain a second polymer electrolyte film.

[0254] The preparation method of the lithium metal battery monomer was the same as that of Example 1, except for the following differences.

[0255] Example 12

[0256] The preparation method of the lithium metal battery monomer was the same as that of Example 1, except for the following differences.

[0257] Preparation of the second polymer electrolyte film

[0258] Styrene sulfonic acid (trifluoromethylsulfonyl) imide lithium monomer was mixed with polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP) in a mass ratio of 8:2 in N-methyl pyrrolidone (NMP), and azobisisobutyronitrile (AIBN) was added as a thermal initiator, with the mass of AIBN being 2% of the mass of the monomer, and the mixture was stirred for 2 h, then the mixture was poured into a polytetrafluoroethylene template and heated in a vacuum oven at 80°C until the NMP was completely volatilized, forming a mixture film with a thickness of 60 μm; ethylene carbonate and propylene carbonate were mixed in a volume ratio of 1:1 as a plasticizer; the plasticizer was added to the mixture film in a mass ratio of 7:10 to completely infiltrate the mixture film, and the template was removed to obtain a second polymer electrolyte film.

[0259] The lithium styrene sulfonate (triflate) imide monomer and polyvinylidene hexafluoropropylene (PVDF-HFP) were mixed in N-methyl pyrrolidone (NMP) at a mass ratio of 8:2, and azobisisobutyronitrile (AIBN) was added as a thermal initiator, with the mass of AIBN being 2% of the mass of the monomer, and the mixture was stirred for 2 hours. Then the mixture was poured into a polytetrafluoroethylene template and heated in a vacuum oven at 80°C until the NMP was completely volatilized, forming a mixture film with a thickness of 60 μm. Ethylene carbonate and propylene carbonate were mixed at a volume ratio of 1:1 as a plasticizer. The plasticizer was added to the mixture film at a mass ratio of 3:10 until the mixture film was completely infiltrated. The template was removed to obtain a second polymer electrolyte film.

[0260] Example 13

[0261] The method for preparing the lithium metal battery monomer was the same as that of Example 1, except for the following differences.

[0262] Preparation of the second polymer electrolyte film

[0263] The lithium styrene sulfonate (triflate) imide monomer and polyvinylidene hexafluoropropylene (PVDF-HFP) were mixed in N-methyl pyrrolidone (NMP) at a mass ratio of 8:2, and azobisisobutyronitrile (AIBN) was added as a thermal initiator, with the mass of AIBN being 2% of the mass of the monomer, and the mixture was stirred for 2 hours. Then the mixture was poured into a polytetrafluoroethylene template and heated in a vacuum oven at 80°C until the NMP was completely volatilized, forming a mixture film with a thickness of 60 μm. Ethylene carbonate and propylene carbonate were mixed at a volume ratio of 1:1 as a plasticizer. The plasticizer was added to the mixture film at a mass ratio of 3:10 until the mixture film was completely infiltrated. The template was removed to obtain a second polymer electrolyte film.

[0264] The lithium styrene sulfonate (triflate) imide monomer and polyvinylidene hexafluoropropylene (PVDF-HFP) were mixed in N-methyl pyrrolidone (NMP) at a mass ratio of 8:2, and azobisisobutyronitrile (AIBN) was added as a thermal initiator, with the mass of AIBN being 2% of the mass of the monomer, and the mixture was stirred for 2 hours. Then the mixture was poured into a polytetrafluoroethylene template and heated in a vacuum oven at 80°C until the NMP was completely volatilized, forming a mixture film with a thickness of 60 μm. Ethylene carbonate and propylene carbonate were mixed at a volume ratio of 1:1 as a plasticizer. The plasticizer was added to the mixture film at a mass ratio of 3:10 until the mixture film was completely infiltrated. The template was removed to obtain a second polymer electrolyte film.

[0265] Example 14

[0266] The method for preparing the lithium metal battery monomer was the same as that of Example 1, except for the following differences.

[0267] Preparation of the second polymer electrolyte membrane

[0268] Dissolve 19.5 g of p-styrene sulfonyl chloride, 15.0 g of CF3SO2NHK and 0.21 g of 4-tert-butyl catechol in 100 ml of acetonitrile and stir at 0°C, then add 7.6 g of pyridine dropwise under a nitrogen atmosphere, heat the mixture at 65°C for 48 h, and then remove the solvent under vacuum; dissolve the obtained product in 100 ml of deionized water, add 6.6 g of K2CO3, and neutralize by stirring at 0°C, then remove the volatile matter under negative pressure at 50°C, and then dry the brown product in an oven at 70°C for 10 h to obtain substance A; mix substance A with LiClO4 in a molar ratio of 1:1 in acetonitrile to obtain a lithium styrene sulfonyl (trifluoromethylsulfonyl) imide monomer.

[0269] Mix the lithium styrene sulfonyl (trifluoromethylsulfonyl) imide monomer with polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP) in a mass ratio of 8:5 in N-methyl pyrrolidone (NMP), and then add azobisisobutyronitrile (AIBN) as a thermal initiator, with the mass of AIBN being 2% of the mass of the monomer, and stir together for 2 h, then pour the mixture into a polytetrafluoroethylene template and heat in a vacuum oven at 80°C until the NMP is completely volatilized, to form a mixture film with a thickness of 60 μm; mix ethylene carbonate and propylene carbonate in a volume ratio of 1:1 as a plasticizer; add the plasticizer dropwise onto the mixture film in a ratio of 5:13 to the mass of the mixture film to completely soak it, remove the template, and obtain a second polymer electrolyte membrane.

[0270] Example 15

[0271] The preparation method of the lithium metal battery monomer is the same as that of Example 1, except for the following differences.

[0272] Preparation of the second polymer electrolyte membrane

[0273] Dissolve 19.5 g of p-styrene sulfonyl chloride, 15.0 g of CF3SO2NHK and 0.21 g of 4-tert-butyl catechol in 100 ml of acetonitrile and stir at 0°C, then add 7.6 g of pyridine dropwise under a nitrogen atmosphere, heat the mixture at 65°C for 48 h, and then remove the solvent under vacuum; dissolve the obtained product in 100 ml of deionized water, add 6.6 g of K2CO3, and neutralize by stirring at 0°C, then remove the volatile matter under negative pressure at 50°C, and then dry the brown product in an oven at 70°C for 10 h to obtain substance A; mix substance A with LiClO4 in a molar ratio of 1:1 in acetonitrile to obtain a lithium styrene sulfonyl (trifluoromethylsulfonyl) imide monomer.

[0274] The lithium styrene sulfonyl (trifluoromethylsulfonyl) imide monomer and polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP) are mixed in N-methyl pyrrolidone (NMP) at a mass ratio of 8:6, and azobisisobutyronitrile (AIBN) is added as a thermal initiator, the mass of AIBN being 2% of the mass of the monomer, and the mixture is stirred for 2 hours, then the mixture is poured into a polytetrafluoroethylene template and heated in a vacuum oven at 80°C until the NMP is completely volatilized, forming a mixture film with a thickness of 60 μm; ethylene carbonate and propylene carbonate are mixed at a volume ratio of 1:1 as a plasticizer; the plasticizer is added to the mixture film at a mass ratio of 5:14 until the mixture film is completely infiltrated, the template is removed, and a second polymer electrolyte film is obtained.

[0275] Table 3

[0276] From the above test results, it can be seen that by further adjusting the composition of the second polymer electrolyte film, the high-voltage lithium metal battery cell can have better cycle performance.

[0277] It should be noted that the present disclosure is not limited to the above embodiments. The above embodiments are only examples, and embodiments having substantially the same configuration and playing the same role and effect within the scope of the technical solutions of the present disclosure are all included in the technical scope of the present disclosure. In addition, within the scope of the main idea of the present disclosure, various modifications that can be thought of by those skilled in the art are applied to the embodiments, and other modes constructed by combining part of the constituent elements in the embodiments are also included in the scope of the present disclosure.

Claims

1. A polymer electrolyte membrane, wherein, The polymer electrolyte membrane includes a first polymer electrolyte membrane and a second polymer electrolyte membrane stacked, the first polymer electrolyte membrane including a first polymer, a first plasticizer, and a first electrolyte salt, and the second polymer electrolyte membrane including a single-ion conductor polymer electrolyte. 2.The polymer electrolyte membrane of claim 1, wherein, the first polymer includes one or more of polyvinylidene fluoride, polymethyl methacrylate, polyamide, polyacrylonitrile, polyvinylidene fluoride-hexafluoropropylene, and derivatives thereof; and / or, the first plasticizer includes one or more of carbonate compounds, nitrile compounds, ether compounds; and / or, the first electrolyte salt includes one or more of lithium bisfluorosulfonylimide, lithium bis-trifluoromethylsulfonylimide, lithium hexafluorophosphate, lithium tetrafluoroborate, lithium hexafluoroarsenate, lithium bisoxalate borate, lithium difluorooxalate borate, lithium difluorophosphate, lithium perchlorate, lithium triflate, lithium difluorodioxalate phosphate, lithium tetrafluorooxalate phosphate. 3.The polymer electrolyte membrane of claim 2, wherein, the first polymer includes one or more of polyvinylidene fluoride-hexafluoropropylene and derivatives thereof; and / or, the first plasticizer includes one or more of ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, vinylene carbonate, dipropyl carbonate, methyl ethyl carbonate, succinonitrile, 1,3-dioxolane, ethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether; and / or, the first electrolyte salt includes one or both of lithium bisfluorosulfonylimide and lithium bis-trifluoromethylsulfonylimide. 4.The polymer electrolyte membrane of any one of claims 1-3, wherein, a mass ratio of the first polymer to the first electrolyte salt is 0.14:1 to 20:1; and / or, a mass ratio of the first polymer to the first plasticizer is 0.5:1 to 10:

1. 5.The polymer electrolyte membrane of any one of claims 1-4, wherein, a mass ratio of the first polymer to the first electrolyte salt is 0.6:1 to 10:1; and / or, a mass ratio of the first polymer to the plasticizer is 1:1 to 3:

1.

6. The polymer electrolyte membrane according to any one of claims 1 to 5, wherein, The first polymer electrolyte membrane further includes first inorganic particles including one or more of inorganic oxide particles, inorganic sulfide particles, inorganic nitride particles, inorganic halide particles. 7.The polymer electrolyte membrane of claim 6, wherein, the first inorganic particles include one or more of silicon oxide, aluminum oxide, titanium oxide, zirconium oxide, silicon nitride, diatomite, montmorillonite, kaolin; and / or, a particle size of the first inorganic particles is 20 nm-300 nm.

8. The polymer electrolyte membrane according to any one of claims 1 to 7, wherein, The single-ion conductor polymer electrolyte includes a polymer backbone, an anion group or an anion acceptor composed of a Lewis acid bonded to the polymer backbone through a chemical bond, and an alkali metal cation combined with the anion group or the anion acceptor. 9.The polymer electrolyte membrane of claim 8, wherein, the polymer skeleton comprises one or more of an acrylic ester structural unit, a styrene structural unit, a maleic anhydride structural unit, a vinylpyrrolidone structural unit, a vinyl alcohol structural unit, an ethylene oxide structural unit, an acrylonitrile structural unit, an ethylene glycol structural unit, an acrylamide structural unit; and / or, the anionic groups include one or more of carboxylate anions CO2 - , carboxylate anion containing organic groups, sulfonate anions SO3 - , sulfonate anion containing organic groups, borate anions BO4 - , borate anion containing organic groups, boron trifluoride anions BF3 - , boron trifluoride anion containing organic groups, fluorosulfonimide anions SO2N (-) SO2F, sulfonimide anion containing organic groups -SO2N (-) SO2-; and / or, The alkali metal cation comprises one or more of Li + , Na + , K + , Mg 2+ , Ba 2+ , Ca 2+ .

10. The polymer electrolyte membrane according to any one of claims 1 to 9, wherein, The single-ion conductor polymer electrolyte includes one or more of the structural units shown below, R1, R3, R5, R7, R9 each independently represent a C1-C5 alkylene group, a C1-C5 haloalkylene group, R2, R4, R6, R8, R 10 each independently represent a carboxylate anion CO2 - , an organic group containing a carboxylate anion, a sulfonate anion SO3 - , an organic group containing a sulfonate anion, a borate anion BO4 - , an organic group containing a borate anion, a boron trifluoride anion BF3 - , an organic group containing a boron trifluoride anion, a fluorosulfonylimide anion SO2N (-) SO2F, an organic group containing a sulfonylimide anion -SO2N (-) SO2-, n is an integer between 1 and 10, m is an integer greater than or equal to 20.

11. The polymer electrolyte membrane according to any one of claims 9-10, wherein, the carboxylate-containing organic group, the sulfonate-containing organic group, the borate- containing organic group, the boron triflate-containing organic group, the sulfonimide- containing organic group -SO2N (-) The organic group in the organic group containing F atoms, cyano CN of SO2- is an organic group.

12. The polymer electrolyte membrane according to any one of claims 1 to 11, wherein, the second polymer electrolyte film further comprises a second polymer, the second polymer comprising one or more of polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene, polyethylene oxide, polyethylene glycol, polyurea, polyurethane, polyamide, and respective derivatives thereof.

13. The polymer electrolyte membrane according to claim 12, wherein, The mass ratio of the single-ion conductor polymer electrolyte to the second polymer is 1.3:1 to 4:

1.

14. The polymer electrolyte membrane according to any one of claims 12-13, wherein, The second polymer electrolyte film further comprises a second plasticizer, the second plasticizer comprising one or more of a carbonate compound, a nitrile compound, an ether compound.

15. The polymer electrolyte film according to claim 14, the second plasticizer comprises one or more of ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, vinylene carbonate, dipropyl carbonate, methyl ethyl carbonate, succinonitrile, 1,3-dioxolane, ethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether; and / or, the mass content of the second plasticizer in the second polymer electrolyte film is 1% to 70%.

16. The polymer electrolyte membrane according to any one of claims 1 to 15, wherein, The second polymer electrolyte film further comprises a second inorganic particle, the second inorganic particle comprising one or more of an inorganic oxide particle, an inorganic sulfide particle, an inorganic nitride particle, an inorganic halide particle.

17. The polymer electrolyte film according to claim 16, the second inorganic particle comprises one or more of silicon oxide, aluminum oxide, titanium oxide, zirconium oxide, silicon nitride, diatomite, montmorillonite, kaolin; and / or, the particle size of the second inorganic particle is 20 nm to 300 nm.

18. The polymer electrolyte film according to any one of claims 1 to 17, the thickness of the first polymer electrolyte film is 10 μm to 200 μm; and / or, the thickness of the second polymer electrolyte film is 10 μm to 200 μm.

19. A battery cell comprising a positive electrode sheet, a negative electrode sheet, and the polymer electrolyte film according to any one of claims 1 to 18, the polymer electrolyte film being located between the positive electrode sheet and the negative electrode sheet.

20. The battery cell of claim 19, wherein, The first polymer electrolyte film is located close to the positive electrode sheet, and the second polymer electrolyte film is located close to the negative electrode sheet.

21. The battery cell according to any one of claims 19 to 20, the positive electrode sheet comprises one or more of a lithium transition metal oxide and a modified material thereof, a lithium-containing phosphate and a modified material thereof, lithium titanate, sulfur, selenium, tellurium; and / or, the negative electrode sheet comprises one or more of lithium, a lithium alloy, natural graphite, artificial graphite, mesocarbon microbeads, soft carbon, hard carbon, a silicon-based material, a tin-based material, lithium titanate, a metal oxide.

22. A battery device comprising a plurality of the battery cell according to any one of claims 19 to 21.

23. An electric device comprising the battery cell of any one of claims 19-21 or the battery device of claim 22.

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