Electrolyte membrane and preparation method therefor, battery, and electric device

Abstract

An electrolyte membrane and a preparation method therefor, a solid-state battery, and an electric device. The electrolyte membrane comprises a polymer electrolyte base membrane and a halide solid electrolyte. The halide solid electrolyte is distributed in the polymer electrolyte base membrane, and the mass of the halide solid electrolyte is 0.05-50% of the mass of the polymer electrolyte base membrane. The electrolyte membrane solves the problem of an existing solid electrolyte membrane having poor interface stability between a positive electrode and a negative electrode.

Description

An electrolyte membrane and its preparation method, a battery and an electrical device thereof

[0001] This application claims priority to Chinese Patent Application No. 202510019148.8, filed on January 6, 2025, entitled "An Electrolyte Membrane and its Preparation Method, Battery and Electrical Device", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application belongs to the field of battery technology, specifically relating to an electrolyte membrane and its preparation method, a battery, and an electrical device. Background Technology

[0003] Traditional solid-state electrolytes exhibit poor interfacial stability with both the positive and negative electrodes, easily forming organic-rich interfacial layers (CEI and SEI) that generate interfacial impedance during charge and discharge, leading to decreased battery performance. While polymer-based solid-state electrolytes possess good mechanical flexibility and processability, they suffer from low ionic conductivity. Therefore, developing a novel solid-state electrolyte membrane to improve battery charge and discharge performance is crucial. Summary of the Invention

[0004] To address the problem of poor interfacial stability between the positive and negative electrodes in existing solid electrolyte membranes, this application provides an electrolyte membrane, its preparation method, a solid-state battery, and an electrical device thereof.

[0005] The technical solution adopted in this application to solve the above-mentioned technical problems is as follows:

[0006] In a first aspect, this application provides an electrolyte membrane comprising a polymer electrolyte substrate membrane and a halide solid electrolyte, wherein the halide solid electrolyte is distributed in the polymer electrolyte substrate membrane, and the mass of the halide solid electrolyte is 0.05% to 50% of the mass of the polymer electrolyte substrate membrane.

[0007] Optionally, the mass of the halide solid electrolyte is 0.1% to 10% of the mass of the polymer electrolyte substrate membrane.

[0008] Optionally, the halide solid electrolyte includes Li a (M b )X c X' dM includes one or more of Ga, Y, In, Mg, Sr, Sc, Sn, Pb, Ti, Zr, Hf, Nb, Ta, W, Fe, Ru, Al, and lanthanide metals; X includes one or more of halogens; X' includes one or more of halide ions, N ions, oxygen-containing anion groups, and pseudohalide anions; 0.5≤a≤5, 0.2≤b≤4, c+d=a+bε, where ε is the weighted average valence of element M.

[0009] Optionally, the oxygen-containing anionic group includes O 2- S 2- CN - CO3 2- PO4 3- P2O7 4- SO4 2- One or more of the following; the pseudohalogen anion includes SCN. - PF6 - NH2 - AlF4 - or BF4 - One or more of them.

[0010] Optionally, the halide solid electrolyte includes Li₂MnCl₄, Li₂ZnCl₄, Li₂ZrOCl₄, LiYbF₄, LiAlF₄, Li₃YCl₆, Li₃InCl₆, and Li₃InCl₄. 5.5 F 0.5 Li3TaCl6, Li 0.388 Ta 0.238 La 0.475 One or more of Cl3 and Li6CoCl8.

[0011] Optionally, the electrolyte membrane further includes a filler distributed in the polymer electrolyte substrate membrane. The filler includes NASICON-type electrolytes, perovskite-type electrolytes, anti-perovskite-type electrolytes, LISICON-type electrolytes, garnet-type electrolytes, Li₂S-P₂S₅, thio-LISCON-type electrolytes, and Li₂S-P₂S₅. 10 GeP2S 12 Li3PS4, Li 6-x PS 5-x Cl 1+x , 0≤x≤0.8、Li 9.54 Si 1.74 P 1.44 S 11.7 Cl 0.3 One or more of them.

[0012] Optionally, the particle size of the halide solid electrolyte is 5 nm to 10 μm; and / or, the particle size of the filler is 5 nm to 10 μm.

[0013] Optionally, the mass of the filler is 0.1% to 20% of the mass of the polymer electrolyte base membrane.

[0014] Optionally, the polymer electrolyte substrate membrane comprises a polymer and a lithium salt, wherein the molar ratio of the polymer to the lithium salt is (5:1) to (20:1).

[0015] Optionally, the polymer includes at least one of polyethylene oxide, polyacrylate, polyvinylidene fluoride, polyvinylidene fluoride hexafluoropropylene copolymer, polysiloxane, polyethylene glycol, sodium polystyrene sulfonate, polysulfone, polyethersulfone, polypropylene carbonate, polymethyl methacrylate, polyacrylonitrile, and polyimide.

[0016] And / or, the lithium salt includes at least one of lithium hexafluorophosphate, lithium hexafluoroarsenate, lithium tetrafluoroborate, lithium hexafluoroantimonyate, lithium bis(trifluoromethanesulfonate imide), lithium trifluoromethanesulfonate, lithium bis(fluorosulfonyl)imide, lithium perchlorate, lithium iodide, lithium magnesium bis(fluorosulfonyl)imide, lithium bis(oxaloacetate borate), and lithium difluorooxaloacetate borate.

[0017] Optionally, at least one of the following conditions must be met:

[0018] The oxidation potential of the composite polymer electrolyte membrane is 4.7V vs. Li / Li. + ;

[0019] The tensile strength of the electrolyte membrane is 2–200 MPa;

[0020] The ionic conductivity of the electrolyte membrane is greater than or equal to 1E-4S / cm;

[0021] The thickness of the electrolyte membrane is 1 μm to 100 μm.

[0022] Secondly, this application provides a method for preparing the electrolyte membrane as described above, comprising the following steps:

[0023] The polymer and the lithium salt are dispersed in a solvent, then a halide solid electrolyte is added, mixed, cast onto a substrate, and dried to obtain an electrolyte membrane.

[0024] Optionally, the solvent includes one or more of acetonitrile, acetone, ethyl acetate, butanone, diethyl ether, hexane, n-heptane, chloroform, tetrahydrofuran, N,N-dimethylformamide, N,N-dimethylacetamide, 2,2,2-trifluoro-N,N-dimethylformamide, and N-methylpyrrolidone.

[0025] Optionally, the drying temperature is 60–160°C, the drying time is 6–24 h, and the relative vacuum degree during drying is -0.1–0 MPa.

[0026] Thirdly, this application provides a method for preparing the electrolyte membrane as described above, comprising the following steps:

[0027] The polymer, lithium salt, and halide solid electrolyte are mixed evenly to obtain a mixture.

[0028] The mixture is hot-pressed to obtain an electrolyte membrane.

[0029] Optionally, the hot pressing temperature is 120–400℃, the pressure is 5–500MPa, and the hot pressing time is 2s–10min.

[0030] Fourthly, this application provides a battery, including a positive electrode and a negative electrode, and further including an electrolyte membrane as described in any one of the above claims; or, an electrolyte membrane prepared by the preparation method of the electrolyte membrane described in any one of the above claims; the electrolyte membrane is located between the positive electrode and the negative electrode.

[0031] Fifthly, this application provides an electrical device including a battery as described in any of the above claims.

[0032] In this application, firstly, a halide solid electrolyte is distributed within a polymer electrolyte substrate membrane, significantly improving the ionic conductivity of the electrolyte membrane. The halide solid electrolyte forms a highly efficient ion conduction channel within the polymer electrolyte substrate membrane, ensuring efficient movement of lithium ions within the battery, thereby enhancing the battery's charge-discharge performance. Simultaneously, the halide solid electrolyte has an interface modification effect, generating a lithium halide-rich interface layer product, which effectively reduces interface impedance and improves the interface stability between the electrolyte and electrode materials. Specifically, a CEI (Chemical Electrolyte Injection) is formed between the electrolyte membrane and the positive electrode material. The halide solid electrolyte forms a stable interface layer on the positive electrode surface, reducing side reactions between the electrolyte and the positive electrode material. This CEI layer not only improves interface stability but also effectively reduces interface impedance, improving the battery's cycle life and overall performance. On the negative electrode surface, the electrolyte membrane forms an SEI (Sediment Electrolyte Injection) through physical and electrochemical interactions. The halide solid electrolyte helps generate a uniform and dense SEI layer, preventing the growth of lithium dendrites. The stable SEI layer improves the battery's safety and long-cycle stability. In addition, the polymer electrolyte substrate membrane provides the necessary flexibility and mechanical strength for the electrolyte membrane, enabling it to adapt to deformation and stress changes within the battery and preventing mechanical damage during use. The addition of halide solid electrolyte further enhances the mechanical properties of the electrolyte membrane, ensuring that it maintains its structural integrity during multiple charge-discharge cycles.

[0033] The preparation methods for electrolyte membranes using simple solution casting or hot pressing processes in the second and third aspects simplify the preparation process, improve the stability and controllability of the process, and reduce production costs. Attached Figure Description

[0034] Figure 1 is a 1000x SEM image of the halide solid electrolyte Li2MnCl4 in the embodiments of this application;

[0035] Figure 2 is a schematic diagram of the ionic conductivity test of the composite electrolyte membrane in Embodiment 1 of this application;

[0036] Figure 3 is a schematic diagram of the electrochemical window test of the composite electrolyte membrane provided in Example 1 of this application. Detailed Implementation

[0037] To make the technical problems, technical solutions, and beneficial effects solved by this application clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0038] One embodiment of this application provides an electrolyte membrane comprising a polymer electrolyte base membrane and a halide solid electrolyte, wherein the halide solid electrolyte is distributed in the polymer electrolyte base membrane, and the mass of the halide solid electrolyte is 0.05% to 50% of the mass of the polymer electrolyte base membrane.

[0039] In this application, the halide solid electrolyte is uniformly distributed within the polymer electrolyte substrate membrane, significantly improving the ionic conductivity of the electrolyte membrane. The halide solid electrolyte forms a highly efficient ion conduction channel within the polymer electrolyte substrate membrane, ensuring efficient movement of lithium ions within the battery, thereby enhancing the battery's charge-discharge performance. Simultaneously, the halide solid electrolyte has an interface modification effect, generating a lithium halide-rich interface layer product, which effectively reduces interface impedance and improves the interfacial stability between the electrolyte and electrode materials. Specifically, a CEI (Chemical Electrolyte Injection) is formed between the electrolyte membrane and the positive electrode material. The halide solid electrolyte forms a stable interface layer on the positive electrode surface, reducing side reactions between the electrolyte and the positive electrode material. This CEI layer not only improves interface stability but also effectively reduces interface impedance, improving the battery's cycle life and overall performance. On the negative electrode surface, the electrolyte membrane forms an SEI (Sediment Electrolyte Injection) through physical and electrochemical interactions. The halide solid electrolyte helps generate a uniform and dense SEI layer, preventing the growth of lithium dendrites. The stable SEI layer improves the battery's safety and long-cycle stability.

[0040] In addition, the polymer electrolyte substrate membrane provides the necessary flexibility and mechanical strength for the electrolyte membrane, enabling it to adapt to deformation and stress changes within the battery and preventing mechanical damage during use. The addition of halide solid electrolyte further enhances the mechanical properties of the electrolyte membrane, ensuring that it maintains its structural integrity during multiple charge-discharge cycles.

[0041] Specifically, the electrolyte membrane is a non-porous membrane, and the mass of the halide solid electrolyte is 0.05%, 0.1%, 0.3%, 0.5%, 0.7%, 0.9%, 1.1%, 1.3%, 1.5%, 1.7%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, or 50% of the mass of the polymer electrolyte substrate membrane.

[0042] In a preferred embodiment, the mass of the halide solid electrolyte is 0.1% to 10% of the mass of the polymer electrolyte base membrane.

[0043] By controlling the content of halide solid electrolyte in the polymer electrolyte substrate membrane, the ionic conductivity and mechanical strength of the formed electrolyte membrane can be adjusted, thereby further enhancing the overall mechanical properties of the electrolyte membrane and ensuring that the electrolyte membrane maintains its structural integrity during multiple charge-discharge cycles.

[0044] In one embodiment, the halide solid electrolyte comprises Li a (M b )X c X' d M includes one or more of Ga, Y, In, Mg, Sr, Sc, Sn, Pb, Ti, Zr, Hf, Nb, Ta, W, Fe, Ru, Al, and lanthanide metals. X includes one or more halogens. X' includes one or more of halide ions, N ions, oxygen-containing anionic groups, and pseudohalo anions. 0.5≤a≤5, 0.2≤b≤4, c+d=a+bε, where ε is the weighted average valence of element M. By selecting the above-mentioned halide solid electrolyte, ion conduction channels can be better formed in the electrolyte membrane, improving the ionic conductivity of the electrolyte membrane and further enhancing the charge and discharge performance of the battery.

[0045] In one embodiment, the oxygen-containing anionic group includes O 2- S 2- CN - CO3 2- PO4 3- P2O7 4- SO42- One or more of the following. The pseudohalo anion includes SCN. - PF6 - NH2 - AlF4 - or BF4 - One or more of them.

[0046] In a preferred embodiment, the halide solid electrolyte includes Li₂MnCl₄, Li₂ZnCl₄, Li₂ZrOCl₄, LiYbF₄, LiAlF₄, Li₃YCl₆, Li₃InCl₆, and Li₃InCl₄. 5.5 F 0.5 Li3TaCl6, Li 0.388 Ta 0.238 La 0.475 One or more of Cl3 and Li6CoCl8.

[0047] In one embodiment, the electrolyte membrane further includes a filler distributed in the polymer electrolyte substrate membrane. The filler includes NASICON (sodium fast ion conductor) type electrolyte, perovskite type electrolyte, anti-perovskite type electrolyte, LISICON (lithium fast ion conductor) type electrolyte, garnet type electrolyte, Li₂S-P₂S₅, thio-LISCON (sulfide lithium fast ion conductor) type electrolyte, and Li₂S-P₂S₅. 10 GeP2S 12 Li3PS4, Li 6-x PS 5-x Cl 1+x , 0≤x≤0.8、Li 9.54 Si 1.74 P 1.44 S 11.7 Cl 0.3 One or more of the above fillers can be used in combination with halide solid electrolytes to further enhance the ionic conductivity and mechanical properties of the electrolyte membrane.

[0048] In a preferred embodiment, the filler comprises Li 3x La 2 / 3-x TiO (0≤x≤0.16), Li 1+y Al y Ti 2-y (PO4)3, 0≤y≤0.5, Li 1+z Al z Ge 2-z (PO4)3, 0≤z≤0.5, Li7La3Zr2O 12 Li₂S-P₂S₅, Li 10 GeP2S 12Li 6-m PS 5-m Cl 1+m , 0≤m≤0.8、Li 3.25 Ge 0.25 P 0.75 S4, Li 9.54 Si 1.74 P 1.44 S 11.7 Cl 0.3 One or more of them.

[0049] In one embodiment, the particle size of the halide solid electrolyte is 5 nm to 10 μm; and / or, the particle size of the filler is 5 nm to 10 μm, for example, 5 nm, 10 nm, 50 nm, 100 nm, 500 nm, 1 μm, 3 μm, 5 μm, 7 μm, or 10 μm. By selecting halide solid electrolytes and fillers within the above particle size range, the halide solid electrolytes and fillers are uniformly distributed in the polymer electrolyte substrate membrane, forming efficient ion conduction channels, ensuring that lithium ions can move efficiently inside the battery, thereby improving the charge and discharge performance of the battery. Furthermore, by selecting halide solid electrolytes and fillers within the above particle size range, it is easy to control their distribution in the polymer electrolyte substrate membrane. Halide solid electrolyte and filler particles that are too small or too large will affect their uniformity in the polymer electrolyte substrate membrane, thereby affecting the mechanical properties of the electrolyte membrane.

[0050] In a preferred embodiment, the particle size of the halide solid electrolyte is 50 nm to 5 μm, and / or the particle size of the filler is 50 nm to 5 μm.

[0051] In one embodiment, the mass of the filler is 0.1% to 20% of the mass of the polymer electrolyte base membrane, such as 0.1%, 0.5%, 1%, 3%, 5%, 7%, 10%, 15%, or 20%. By controlling the content of the filler in the polymer electrolyte base membrane, the ionic conductivity and mechanical strength of the polymer electrolyte base membrane can be adjusted, thereby enhancing its mechanical properties.

[0052] In one embodiment, the polymer electrolyte substrate membrane comprises a polymer and a lithium salt, wherein the molar ratio of the polymer to the lithium salt is (5:1) to (20:1). Specifically, the molar ratio of the polymer to the lithium salt includes, but is not limited to, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 11:1, 12:1, 13:1, 12:1, 15:1, 16:1, 17:1, 18:1, 19:1, or 20:1. By limiting the molar ratio of the polymer to the lithium salt, the flexibility of the polymer electrolyte substrate membrane is adjusted, enabling the electrolyte membrane to adapt to deformation and stress changes inside the battery, and preventing mechanical damage to the electrolyte membrane during use.

[0053] In one embodiment, the polymer includes at least one selected from polyethylene oxide, polyacrylate, polyvinylidene fluoride, polyvinylidene fluoride hexafluoropropylene copolymer, polysiloxane, polyethylene glycol, sodium polystyrene sulfonate, polysulfone, polyethersulfone, polypropylene carbonate, polymethyl methacrylate, polyacrylonitrile, and polyimide. Selecting the above polymers facilitates the adjustment of the flexibility and mechanical strength of the polymer electrolyte base membrane.

[0054] And / or, the lithium salt includes at least one of lithium hexafluorophosphate, lithium hexafluoroarsenate, lithium tetrafluoroborate, lithium hexafluoroantimonyate, lithium bis(trifluoromethanesulfonate imide), lithium trifluoromethanesulfonate, lithium bis(fluorosulfonyl)imide, lithium perchlorate, lithium iodide, lithium magnesium bis(fluorosulfonyl)imide, lithium bis(oxaloacetate borate), and lithium difluorooxaloacetate borate.

[0055] In one embodiment, at least one of the following conditions is satisfied:

[0056] The oxidation potential of the electrolyte membrane is 4.7V vs. Li / Li. + ;

[0057] The tensile strength of the electrolyte membrane is 2–200 MPa;

[0058] The ionic conductivity of the electrolyte membrane is greater than or equal to 1E-4S / cm;

[0059] The thickness of the electrolyte membrane is 1 μm to 100 μm.

[0060] In a preferred embodiment, the thickness of the electrolyte membrane is 10 μm to 30 μm. It should be noted that the thickness of the electrolyte membrane can be adjusted according to the needs of the battery and is not limited to the above range.

[0061] Secondly, one embodiment of this application also provides a method for preparing the electrolyte membrane as described above, comprising the following steps:

[0062] The polymer and the lithium salt are dispersed in a solvent, then a halide solid electrolyte is added, mixed, and cast onto a substrate. After drying, an electrolyte membrane is obtained. This method of preparing the electrolyte membrane through a simple solution casting process simplifies the preparation process, improves the stability and controllability of the process, and reduces production costs.

[0063] In one embodiment, the solvent includes one or more of acetonitrile, acetone, ethyl acetate (EA), butanone, diethyl ether, hexane, n-heptane, chloroform, tetrahydrofuran (THF), N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), 2,2,2-trifluoro-N,N-dimethylformamide, and N-methylpyrrolidone (NMP).

[0064] In one embodiment, the drying temperature is 60–160°C, the drying time is 6–24 h, and the relative vacuum during drying is -0.1–0 MPa. The electrolyte membrane obtained by this method contains solvent residue. This residual solvent binds to the lithium cations in the lithium salt in a complex form, which facilitates the dissociation and conduction of the lithium salt.

[0065] Furthermore, the residual solvent content in the electrolyte membrane is 2% to 15% relative to the mass of solvent added during the preparation process.

[0066] Furthermore, the residual solvents include one or more of acetonitrile, DMF, DMAc, and NMP.

[0067] Thirdly, one embodiment of this application also provides a method for preparing the electrolyte membrane as described above, comprising the following steps:

[0068] The polymer, lithium salt, and halide solid electrolyte are mixed evenly to obtain a mixture.

[0069] The mixture is hot-pressed to obtain an electrolyte membrane.

[0070] The preparation of electrolyte membranes via hot pressing does not use solvents, avoiding adverse side reactions of solvents on electrolyte materials, making it environmentally friendly, and the process is simple and easy to manufacture. Specifically, the mixing methods for the mixture include, but are not limited to, differential speed mixers, fluidized bed mixers, VC mixers, and air jet mills. The vacuum degree during mixing is -0.1 to 0 MPa, the mixing time is 0.2 to 2 hours, and the material temperature is controlled to be less than or equal to 60°C during mixing.

[0071] In one embodiment, the hot pressing temperature is 120–400°C, the pressure is 5–300 MPa, and the hot pressing time is 2 seconds–10 minutes.

[0072] In a preferred embodiment, the hot pressing temperature is 180–240°C, the pressure is 80–200 MPa, and the hot pressing time is 0.5–3 min.

[0073] Fourthly, one embodiment of this application also provides a battery, including a positive electrode and a negative electrode, and further including an electrolyte membrane as described in any of the above claims. Alternatively, an electrolyte membrane prepared by the method described in any of the above claims. The electrolyte membrane is located between the positive electrode and the negative electrode.

[0074] In one embodiment, the positive electrode includes a positive electrode active material, which includes one or more of lithium nickel cobalt manganese oxide, nickel cobalt aluminum, nickel cobalt manganese aluminum, lithium iron manganese phosphate, lithium iron phosphate, lithium manganese oxide, lithium cobalt oxide, lithium nickel oxide, lithium lithium manganese-based oxide, lithium nickel manganese oxide, and lithium vanadium oxide phosphate.

[0075] The negative electrode includes a negative electrode active material, which includes one or more of graphite, LTO, Si, silicon suboxide, silicon dioxide, Si-C, lithium metal, lithium alloy, Sn, Sn-C, SnO2, and tin alloy.

[0076] The negative electrode may also contain only a current collector, which may be pure copper or a copper composite current collector.

[0077] The composite current collector includes a polymer base film and a conductive layer. The conductive layer is on both sides of the polymer base film. The polymer base film includes polyethylene, polyethylene terephthalate, polyimide, polypropylene, polyethylene, polyamide, polyphenylene sulfide or a combination thereof, and has a thickness of 1 to 300 μm.

[0078] The conductive layer is made of copper and has a thickness of 0.01–100 μm.

[0079] On the other hand, one embodiment of this application provides an electrical device including a battery as described in any of the above claims. It should be noted that the battery can be a laminated, wound, or cylindrical battery.

[0080] The present application will be further illustrated by the following examples.

[0081] Example 1

[0082] This embodiment illustrates the electrolyte membrane and its preparation method disclosed in this application, as well as the solid-state battery, and includes the following operational steps:

[0083] Electrolyte membrane: Polyethylene oxide and lithium hexafluorophosphate are dispersed in acetonitrile solvent, followed by the addition of halide solid electrolyte Li₂MnCl₄ and filler Li₇La₃Zr₂O. 12 After mixing, the mixture is cast onto a substrate and dried at 100°C and 0MPa for 12 hours to remove the mixed solvent, thus obtaining an electrolyte membrane.

[0084] The molar ratio of polymer to lithium salt is 10:1, the mass of the halide solid electrolyte is 3% of the total mass of polymer and lithium salt, and the mass of the filler is 3% of the total mass of polymer and lithium salt. Li₂MnCl₄ and filler Li₇La₃Zr₂O are used. 12 The average particle size is 200 nm.

[0085] Preparation of positive electrode

[0086] The positive electrode active material NCM811, conductive carbon black Super-P, and binder polyvinylidene fluoride (PVDF) were mixed in a mass ratio of 93:4:3, and then dispersed in an appropriate amount of N-methyl-2-pyrrolidone (NMP) to obtain the positive electrode slurry. The obtained slurry was uniformly coated on both sides of an aluminum foil, and after drying, calendering, and vacuum drying, aluminum leads were welded on using an ultrasonic welding machine to obtain the positive electrode sheet with a thickness between 120-150 μm.

[0087] Preparation of negative electrode

[0088] The negative electrode uses a metallic lithium negative electrode.

[0089] Preparation of electrolyte

[0090] The fourth solvent, ethylene carbonate, and methyl ethyl carbonate, were mixed at a mass ratio of 7:3. The first additive, tripropynyl phosphate, and the second additive, vinylene carbonate, were added to the solvent and dispersed. Then, lithium hexafluorophosphate (LiPF6) was added at a concentration of 1 mol / L. The volume ratio of the first additive, tripropynyl phosphate, to the solvent was 1:10, and the content of the second additive in the electrolyte was 2%.

[0091] Cell manufacturing

[0092] An electrolyte membrane is placed between the positive and negative electrode sheets prepared above. Then, the sandwich structure consisting of the positive electrode sheet, negative electrode sheet and electrolyte membrane is stacked and packaged with an aluminum-plastic film to produce a soft-pack battery cell with a capacity of 1Ah ready for electrolyte injection.

[0093] Solid-state batteries are obtained by injecting electrolyte and forming the cells.

[0094] Examples 2-28

[0095] Examples 2-28 are used to illustrate the electrolyte membrane disclosed in this application, including most of the operating steps in Example 1 above, except that the formulations in Tables 1 and 2 are used.

[0096] Example 29

[0097] This embodiment illustrates the electrolyte membrane and its preparation method disclosed in this application, as well as the solid-state battery. It includes most of the operational steps in Embodiment 1 above, except that the preparation of the electrolyte membrane includes the following steps:

[0098] Polyethylene oxide, lithium hexafluorophosphate, Li₂MnCl₄ halide solid electrolyte, and Li₇La₃Zr₂O filler were used to prepare the polymer. 12 Mix thoroughly to obtain a mixture.

[0099] The mixture was hot-pressed at 200°C and 50 MPa to obtain an electrolyte membrane.

[0100] Comparative Examples 1-2

[0101] Comparative Examples 1 and 2 are used to illustrate the electrolyte membrane and its preparation method disclosed in this application, including most of the operation steps in Example 1, except that the formulation in Table 1 is used.

[0102] Comparative Example 3

[0103] Comparative Example 3 is used to illustrate the electrolyte membrane and its preparation method disclosed in this application. It includes most of the operational steps in Example 1 above, except that the preparation of the electrolyte membrane includes the following steps:

[0104] Polyethylene oxide and lithium hexafluorophosphate were dispersed in acetonitrile solvent, mixed and cast onto a substrate, and then dried at 100°C and 0 MPa for 12 h to remove the solvent, forming a polymer electrolyte membrane.

[0105] The halide solid electrolyte Li2MnCl4 and the filler Li7La3Zr2O were used. 12 The mixture is mixed with PVDF binder to obtain a mixture material. The mixture material is sheared to fiberize the binder. The mixture material is rolled to form an inorganic solid electrolyte membrane. The inorganic solid electrolyte membrane is combined with a polymer electrolyte membrane to obtain a composite electrolyte membrane.

[0106] Table 1

[0107] Table 2

[0108] Performance testing

[0109] I. The following performance tests were performed on the solid-state batteries obtained in the above embodiments and comparative examples:

[0110] 1. Charge-discharge test: The prepared lithium-ion batteries were charged at 0.1C within the range of 3.0-4.3V and at a constant test temperature of 25℃±2℃, and then left to rest for 10 minutes. After that, they were discharged at 0.33C and left to rest for 30 minutes. The capacity retention rate was calculated.

[0111] 2. Ionic conductivity measurement: The electrolyte membrane is sandwiched between two stainless steel sheets and placed in the casing of a 2032 battery. The ionic conductivity is measured using an electrochemical impedance spectroscopy instrument. The formula is: σ = L / AR, where L is the thickness of the electrolyte membrane, A is the room temperature area of ​​the stainless steel sheet, and R is the measured impedance.

[0112] 3. Electrolyte membrane mechanical property testing:

[0113] Multiple rectangular specimens of uniform size were cut from the composite polymer membrane, ensuring that the edges of the specimens were smooth and free of cracks. The specimen dimensions were cut according to ASTM D882 standard. The specimens were placed in a standard test environment (temperature 23℃±2℃, relative humidity 50%±5%) for at least 24 hours to equilibrate and avoid the influence of the environment on the membrane performance. The membrane specimens were fixed on the fixture of the tensile testing machine, ensuring that their edges were aligned and wrinkle-free. The tensile speed was set, the tensile testing machine was started, and the force-displacement data during the tensile process were recorded. When the specimen broke, the force and elongation at the fracture point were recorded.

[0114] 4. Electrochemical window measurement: The electrolyte membrane is sandwiched between a stainless steel sheet and a lithium sheet, with the lithium sheet facing the electrolyte membrane. The membrane is placed in the 2032 battery case and a linear voltammetric scan is performed using an electrochemical workstation. The scan range is 0V to 5V and the scan rate is 0.5mV / s.

[0115] 5. Residual solvent in the electrolyte membrane:

[0116] Gas chromatography (GC) involves desorbing residual solvent from an electrolyte membrane by heating, allowing the solvent to be separated and quantitatively detected in a gas chromatograph. The membrane sample is placed in a sealed container and heated to evaporate the solvent. The evaporated gas is carried by a carrier gas (such as nitrogen or helium) into the chromatographic column for separation. The solvent peak is recorded using a detector (such as a flame ionization detector), and quantification is performed based on a standard curve.

[0117] 6. Characterization of the types of solvent residues in the electrolyte membrane:

[0118] Gas chromatography-mass spectrometry (GC-MS) combines the separation capabilities of gas chromatography with the molecular weight analysis capabilities of mass spectrometry, identifying solvent types based on their molecular weight and fragmentation information. Electrolyte samples are heated to a specific temperature, causing residual solvents to evaporate. These evaporated solvents then enter a gas chromatography column for separation, with different solvents exhibiting different residence times within the column. After entering the mass spectrometer detector, the solvent types are identified using their molecular weight and fragmentation information.

[0119] The test results are shown in Table 3.

[0120] Table 3

[0121] As shown in Table 3, the test results of Examples 1-5, 13 and Comparative Examples 1-3 indicate that adding halide solid electrolytes and other electrolyte fillers to the polymer electrolyte base film improves its ionic conductivity and further enhances the charge-discharge performance of the battery. The test results of Example 1 and Comparative Example 3 show that, compared to directly placing a layer containing halide solid electrolytes and other electrolyte fillers on top of the polymer electrolyte base film, adding halide solid electrolytes and other electrolyte fillers to the polymer electrolyte base film results in a higher electrochemical window for Example 1 than for Comparative Examples 3 and 1. This demonstrates that introducing halide solid electrolytes into the polymer electrolyte base film has an interface modification effect. The resulting lithium halide-rich interface layer product effectively reduces interface impedance, improves the interface stability between the electrolyte and electrode materials, and also effectively reduces interface impedance, thereby improving the battery's cycle life and overall performance. As the content of halide solid electrolyte changes, the ionic conductivity, tensile strength, and electrochemical window of the electrolyte membrane are all affected. When the content of halide solid electrolyte is too low, although the tensile strength of the electrolyte membrane increases, the ionic conductivity and electrochemical window decrease. When the content of halide solid electrolyte is too high, the tensile strength of the electrolyte membrane decreases significantly.

[0122] The test results of Examples 1, 8-12 show that excessively large particle size of halide solid electrolytes and fillers reduces the tensile strength of the electrolyte membrane, affecting its mechanical properties. The test results of Examples 1, 13-16 show that when the filler content is too high, the conductivity and tensile strength of the electrolyte membrane decrease significantly, thereby deteriorating the battery's charge / discharge performance.

[0123] As can be seen from the test results of Examples 1, 17-20, as the molar ratio of polymer to lithium salt changes, the conductivity of the battery and the tensile strength and ionic conductivity of the electrolyte membrane are all affected. When the polymer content is too high, its ionic conductivity decreases, thereby deteriorating the battery's capacity retention rate.

[0124] As can be seen from the test results of Examples 1 and 23-29, depending on the solvent added in the preparation method of the electrolyte membrane and the drying conditions, the residual amount and type of solvent in the electrolyte membrane are different. When the residual amount of solvent increases, the residual solvent combines with the lithium cation in the lithium salt in the form of a complex, which improves the ionic conductivity of the electrolyte membrane and helps the dissociation and conduction of the lithium salt. When the residual amount of solvent decreases or even disappears, the ionic conductivity of the electrolyte membrane decreases.

[0125] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. An electrolyte membrane, characterized in that, It includes a polymer electrolyte base membrane and a halide solid electrolyte, wherein the halide solid electrolyte is distributed in the polymer electrolyte base membrane, and the mass of the halide solid electrolyte is 0.05% to 50% of the mass of the polymer electrolyte base membrane.

2. The electrolyte membrane according to claim 1, characterized in that, The mass of the halide solid electrolyte is 0.1% to 10% of the mass of the polymer electrolyte base membrane.

3. The electrolyte membrane according to claim 1, characterized in that, The halide solid electrolyte includes Li a (M b )X c X' d Wherein, M is selected from one or more of Ga, Y, In, Mg, Sr, Sc, Sn, Pb, Ti, Zr, Hf, Nb, Ta, W, Fe, Ru, Al, and lanthanide metals; X is selected from one or more of halogens; X' is selected from one or more of halide ions, N ions, oxygen-containing anion groups, and pseudohalide anions; 0.5≤a≤5, 0.2≤b≤4, c+d=a+bε, where ε is the weighted average valence of element M.

4. The electrolyte membrane according to claim 3, characterized in that, The oxygen-containing anion group includes O 2- S 2- CN - CO3 2- PO4 3- P2O7 4- SO4 2- One or more of the following; the pseudohalo anion includes SCN. - PF6 - NH2 - AlF4 - or BF4 - One or more of them.

5. The electrolyte membrane according to claim 3, characterized in that, The halide solid electrolytes include Li₂MnCl₄, Li₂ZnCl₄, Li₂ZrOCl₄, LiYbF₄, LiAlF₄, Li₃YCl₆, Li₃InCl₆, and Li₃InCl₄. 5.5 F 0.5 Li3TaCl6, Li 0.388 Ta 0.238 La 0.475 One or more of Cl3 and Li6CoCl8.

6. The electrolyte membrane according to any one of claims 1 to 5, characterized in that, The electrolyte membrane further includes fillers distributed within the polymer electrolyte substrate membrane. The fillers include NASICON-type electrolytes, perovskite-type electrolytes, anti-perovskite-type electrolytes, LISICON-type electrolytes, garnet-type electrolytes, Li₂S-P₂S₅, thio-LISCON-type electrolytes, and Li₂S-P₂S₅. 10 GeP2S 12 Li3PS4, Li 6-x PS 5-x Cl 1+x , 0≤x≤0.8、Li 9.54 Si 1.74 P 1.44 S 11.7 Cl 0.3 One or more of them.

7. The electrolyte membrane according to claim 6, characterized in that, The particle size of the halide solid electrolyte is 5 nm to 10 μm; and / or the particle size of the filler is 5 nm to 10 μm.

8. The electrolyte membrane according to claim 6, characterized in that, The mass of the filler is 0.1% to 20% of the mass of the polymer electrolyte base membrane.

9. The electrolyte membrane according to claim 1, characterized in that, The polymer electrolyte substrate membrane comprises a polymer and a lithium salt, wherein the molar ratio of the polymer to the lithium salt is (5:1) to (20:1).

10. The electrolyte membrane according to claim 8, characterized in that, The polymer is selected from at least one of polyethylene oxide, polyacrylate, polyvinylidene fluoride, polyvinylidene fluoride hexafluoropropylene copolymer, polysiloxane, polyethylene glycol, sodium polystyrene sulfonate, polysulfone, polyethersulfone, polypropylene carbonate, polymethyl methacrylate, polyacrylonitrile, and polyimide. And / or, the lithium salt is selected from at least one of lithium hexafluorophosphate, lithium hexafluoroarsenate, lithium tetrafluoroborate, lithium hexafluoroantimonyate, lithium bis(trifluoromethanesulfonate imide), lithium trifluoromethanesulfonate, lithium bis(fluorosulfonyl)imide, lithium perchlorate, lithium iodide, lithium magnesium bis(fluorosulfonyl)imide, lithium bis(oxaloyl)borate, and lithium difluorooxaloylborate.

11. The electrolyte membrane according to claim 1, characterized in that, At least one of the following conditions must be met: The oxidation potential of the electrolyte membrane is 4.7V vs. Li / Li. + ; The tensile strength of the electrolyte membrane is 2–200 MPa; The ionic conductivity of the electrolyte membrane is greater than or equal to 1E-4S / cm; The thickness of the electrolyte membrane is 1 μm to 100 μm.

12. A method for preparing an electrolyte membrane according to any one of claims 1 to 11, characterized in that, Includes the following steps: The polymer and the lithium salt are dispersed in a solvent, then a halide solid electrolyte is added, mixed, cast onto a substrate, and dried to obtain an electrolyte membrane.

13. The method for preparing the electrolyte membrane according to claim 12, characterized in that, The solvent is selected from one or more of acetonitrile, acetone, ethyl acetate, butanone, diethyl ether, hexane, n-heptane, chloroform, tetrahydrofuran, N,N-dimethylformamide, N,N-dimethylacetamide, 2,2,2-trifluoro-N,N-dimethylformamide, and N-methylpyrrolidone.

14. The method for preparing the electrolyte membrane according to claim 12, characterized in that, The drying temperature is 60–160°C, the drying time is 6–24 h, and the relative vacuum degree during drying is -0.1–0 MPa.

15. A method for preparing an electrolyte membrane as described in any one of claims 1 to 11, characterized in that, Includes the following steps: The polymer, lithium salt, and halide solid electrolyte are mixed evenly to obtain a mixture. The mixture is hot-pressed to obtain an electrolyte membrane.

16. The method for preparing the electrolyte membrane according to claim 15, characterized in that, The hot pressing temperature is 120–400℃, the pressure is 5–500MPa, and the hot pressing time is 2s–10min.

17. A battery, characterized in that, It includes a positive electrode and a negative electrode, and further includes an electrolyte membrane as described in any one of claims 1 to 11; or, an electrolyte membrane prepared by the method for preparing an electrolyte membrane as described in any one of claims 12 to 16; wherein the electrolyte membrane is located between the positive electrode and the negative electrode.

18. An electrical appliance, characterized in that, Includes the battery as described in claim 17.

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