Polymer solid electrolyte membrane, preparation method therefor, solid-state battery, and electrical apparatus

Abstract

A polymer solid electrolyte membrane, a preparation method therefor, a solid-state battery, and an electrical apparatus, belonging to the field of batteries. The preparation method comprises: mixing a zinc salt, a lithium imide salt, a polymer matrix, and an organic solvent, drying, pre-pressing and forming, and then performing hot pressing for 35-45 minutes at 10-15 MPa and a temperature of 100-120°C. The decomposition temperature of the lithium imide salt is greater than the hot-pressing temperature. The polymer matrix contains polar functional groups. The melting temperature is less than or equal to 100°C, and the glass transition temperature is less than or equal to -15°C. The lithium imide salt and the polymer matrix are jointly used as a main body, and the mass ratio of the zinc salt to the main body is (0.8-1.2):100. The prepared polymer solid electrolyte membrane has a block structure having flexible chain segments and rigid chain segments that alternate with each other, and the polymer solid electrolyte membrane can effectively improve the cycle performance of a solid-state battery.

Description

Polymer solid electrolyte membrane, preparation method thereof, solid-state battery and electric device

[0001] Cross-reference to related applications

[0002] This application claims priority to Chinese Patent Application No. 202410660513.9, filed on May 27, 2024, entitled “Polymer solid electrolyte membrane, preparation method thereof, solid-state battery and electric device”, the entire contents of which are incorporated herein by reference. TECHNICAL FIELD

[0003] The present application relates to the field of solid-state batteries, and in particular, to a polymer solid electrolyte membrane, a preparation method thereof, a solid-state battery and an electric device. BACKGROUND

[0004] Polymer electrolytes have good safety, high interfacial compatibility, low cost, easy processing and other advantages, and are ideal materials for the next generation of solid-state batteries. Compared with traditional liquid electrolytes, solid-state electrolytes can effectively reduce the risk of liquid leakage and electrolyte evaporation, and also avoid the problems of poor thermal stability of traditional separators and poor electrolyte wettability.

[0005] The commonly used polymer framework of existing polymer solid electrolytes includes polyvinylidene fluoride (PVDF), polyethylene oxide (PEO), polymethyl methacrylate (PMMA), polyacrylonitrile (PAN) and multi-component copolymer materials, etc. The currently used polymer electrolytes have the advantages of good flexibility, low interfacial impedance with electrode materials, good film-forming property and low cost, etc. However, their low ionic conductivity and poor mechanical strength seriously affect the electrical performance and safety performance of solid-state batteries, especially the cycle life, which also restricts their commercialization and industrialization applications.

[0006] SUMMARY

[0007] The present application provides a polymer solid electrolyte membrane, a preparation method thereof, a solid-state battery and an electric device. The polymer solid electrolyte membrane has good mechanical properties and ionic conductivity, and when applied to a solid-state battery, it can effectively improve the cycle performance of the solid-state battery, and make the solid-state battery have good long-term and short-term electrical performance and safety performance.

[0008] Embodiments of the present application are implemented as follows:

[0009] In a first aspect, the present application provides a preparation method of a polymer solid electrolyte membrane, comprising the following steps:

[0010] Mixing a zinc salt, a lithium imide salt, a polymer matrix and an organic solvent for dissolving the polymer matrix, drying to obtain a precursor;

[0011] After pre-pressing the precursor, the obtained blank is hot-pressed under the condition of a hot-pressing pressure of 10-15 MPa and a hot-pressing temperature of 100-120℃ for 35-45 min.

[0012] The decomposition temperature of the lithium imide salt is greater than the hot-pressing temperature, the melting temperature of the polymer matrix is less than or equal to 100℃ and the glass transition temperature of the polymer matrix is less than or equal to -15℃, the polymer matrix contains a polar functional group, the polar functional group includes -OH and / or -C-O-C, the lithium imide salt and the polymer matrix are used together as a main body, and the mass ratio of the zinc salt to the main body is (0.8-1.2):100.

[0013] The preparation method provided by the application is simple and controllable, and the cooperation of the raw materials with a specific mass ratio and the specific hot-pressing condition enables the polymer solid electrolyte film to have zinc ion-containing aggregate particles with a nanometer-micrometer scale as crosslinking points, and the flexible chain segments and the rigid chain segments alternately present a three-dimensional network block structure, so that the cycle performance of the solid-state battery can be effectively improved when the polymer solid electrolyte film is applied to the solid-state battery.

[0014] In some embodiments, the zinc salt includes a zinc halide, and the zinc halide includes at least one of zinc fluoride, zinc chloride, zinc bromide, and zinc iodide.

[0015] In some embodiments, the polymer matrix includes at least one of polyvinyl alcohol, polyethylene oxide, polypropylene oxide, and polybutylene oxide.

[0016] In some embodiments, the polymer matrix has a molecular weight of 10,000-18,000.

[0017] In some embodiments, the polymer matrix has a molecular weight of 12,000-15,000.

[0018] In some embodiments, the lithium imide salt includes lithium bis-trifluoromethanesulfonimide.

[0019] In some embodiments, the mass ratio of the lithium imide salt to the polymer matrix is (25-35):(65-75).

[0020] In some embodiments, the organic solvent includes at least one of anisole, dichloroethane, chloroform, and dimethylformamide.

[0021] In some embodiments, the pre-pressing includes pressing under the condition of 10-15 MPa for 10-15 min.

[0022] In some embodiments, the mixing includes:

[0023] The polymer matrix is dissolved in the organic solvent to obtain a polymer solution.

[0024] The zinc salt and the lithium imide salt are mixed with the polymer solution under stirring.

[0025] In some embodiments, the drying is low-temperature vacuum drying at 50-80°C.

[0026] In a second aspect, the application provides a polymer solid-state electrolyte film prepared by the preparation method of the first aspect.

[0027] The polymer solid-state electrolyte film provided by the application has a block structure in which flexible segments and rigid segments are alternately present in a three-dimensional network, and when the polymer solid-state electrolyte film is applied in a solid-state battery, the cycle performance of the solid-state battery can be effectively improved, and the solid-state battery has good long-term and short-term electrical performance and safety performance.

[0028] In a third aspect, the application provides a polymer solid-state electrolyte film, the solid-state electrolyte film has a block structure in which rigid segments and flexible segments are alternately connected to present a three-dimensional network.

[0029] The rigid segment is a zinc ion-containing aggregate particle with a nanometer-micrometer scale as a crosslinking point, and a plurality of polymer molecular chains are crosslinked to form a certain rigid entanglement body through coordination reaction between the zinc ion-containing aggregate particle and the polar functional group on the polymer matrix, and the polar functional group includes -OH and / or -C-O-C-.

[0030] The flexible segment is a free polymer free molecular chain.

[0031] In a fourth aspect, the application provides a solid-state battery comprising the polymer solid-state electrolyte film provided in the second aspect or the third aspect.

[0032] In a fifth aspect, the application provides an electric device comprising the solid-state battery provided in the fourth aspect. BRIEF DESCRIPTION OF DRAWINGS

[0033] In order to more clearly illustrate the technical solutions of the embodiments of the application, the following will briefly introduce the drawings needed in the embodiments. It should be understood that the following drawings only show some embodiments of the application, and therefore should not be considered as limiting the scope. For those skilled in the art, other related drawings can also be obtained without creative labor.

[0034] FIG. 1 is a preparation flow and principle diagram of a polymer solid-state electrolyte film prepared by the preparation method provided by the application;

[0035] FIG. 2 is a schematic diagram of lithium ion transport in the polymer solid-state electrolyte prepared by the application. DETAILED DESCRIPTION

[0036] The embodiments of the present application will be described in detail below with reference to the examples, but those skilled in the art will understand that the following examples are only for illustration of the present application and should not be regarded as limiting the scope of the present application. The specific conditions are not specified in the examples, and the conventional conditions or the conditions recommended by the manufacturer are used. The reagents or instruments used are not specified by the manufacturer, and are conventional products that can be obtained by commercial purchase.

[0037] The following will be specifically described for the polymer solid electrolyte membrane and the preparation method thereof, the solid-state battery and the electric device according to the embodiments of the present application:

[0038] The present application provides a preparation method of a polymer solid electrolyte membrane, which comprises the following steps:

[0039] The zinc salt, the lithium imide salt, the polymer matrix and the organic solvent for dissolving the polymer matrix are mixed and dried to obtain a precursor;

[0040] After pre-pressing the precursor, the obtained green body is hot-pressed under the conditions of a hot-pressing pressure of 10 Mpa to 15 Mpa and a hot-pressing temperature of 100℃ to 120℃ for 35 min to 45 min;

[0041] The decomposition temperature of the lithium imide salt is greater than the hot-pressing temperature, the melting temperature of the polymer matrix is ≤100℃ and the glass transition temperature is ≤-15℃, the polymer matrix contains a polar functional group, the polar functional group includes -OH and / or -C-O-C-, the lithium imide salt and the polymer matrix are used as the main body together, and the mass ratio of the zinc salt to the main body is (0.8-1.2):100.

[0042] Figure 1 is a preparation process and principle diagram of the polymer solid electrolyte membrane prepared by the preparation method provided by the present application; part (a) of Figure 1 shows that the precursor is hot-pressed and solidified to crosslink the polymer polymer solid electrolyte; and part (b) of Figure 1 is a block structure design mechanism of the polymer solid electrolyte.

[0043] In combination with Figure 1, the above preparation method provided by the present application is hot-pressed by specific mass ratio of raw materials and specific parameters, so that the polymer is in a molten state in the early stage of hot-pressing (initial stage of solidification), the Zn 2+The ether oxygen group on the polymer segment of the polymer matrix reacts first, so that the zinc salt slowly dissolves in the molten polymer and continues to react to form nanoparticles. As the hot-pressing time increases, the electrolyte viscosity increases, and the continuously reacting zinc salt particles will agglomerate in the molecular chain gap to form nanometer-sized zinc ion-containing agglomerate particles. As the particle size of the zinc ion-containing agglomerate particles increases, the number of coordination reaction binding sites provided around increases, so that the zinc ion-containing agglomerate particles are used as crosslinking points, and the zinc ion-containing agglomerate particles and the polar functional groups on the polymer matrix are used for coordination reaction to crosslink multiple polymer molecular chains to form a certain rigid crosslinked body, which is a rigid segment; at the same time, the distance between the crosslinking points is extended, and a flexible segment is formed between the two crosslinking points. The flexible segment is a free polymer free molecular chain. That is, after the polymer solid-state electrolyte film is solidified by hot-pressing, the rigid segment is crystalline, which gives the polymer solid-state electrolyte strong mechanical properties; the flexible segment is amorphous, which gives the molecular chain good relaxation and mobility. The flexible segment and the rigid segment alternately present a three-dimensional network block structure.

[0044] Figure 2 is a schematic diagram of lithium ion transmission in the polymer solid-state electrolyte film prepared in the present application. In the polymer solid-state electrolyte film, lithium ions are complexed with polar groups (-OH, C-O-C, etc.) on the polymer molecular chain, and are decomplexed during the charging and discharging process of the battery. Then, the lithium ions are complexed with adjacent molecular chains by moving along the polymer molecular chain, and the process is repeated to achieve lithium ion migration.

[0045] In combination with Figure 1 and Figure 2, the block polymer polymer solid-state electrolyte prepared by the above preparation method not only can construct a stable lithium ion transmission network by using the unique structure of alternating rigid and flexible segments, effectively inhibit the capacity attenuation and lithium dendrite generation of the battery, but also can effectively prevent the destruction of the electrolyte structure by external factors or lithium dendrites. 2+ In addition to being a crosslinking point, it can also capture part of the TFSI - , so that more Li + can migrate on the polymer chain, thereby improving the conductivity, and the mechanical properties are good and have certain ductility, which can effectively prevent the destruction of the electrolyte structure by external factors or lithium dendrites.

[0046] Among them, the lithium imide salt is selected as the electrolyte salt, which is beneficial to improve the cycle performance of the solid-state battery, and by controlling the decomposition temperature of the lithium imide salt to be greater than the hot-pressing temperature, it is beneficial to inhibit the decomposition of the lithium imide salt during the hot-pressing process to form the polymer solid-state electrolyte film, and it is beneficial to maintain the high ionic conductivity of the polymer solid-state electrolyte film.

[0047] By limiting the polymer matrix melting temperature ≤ 100℃ and the glass transition temperature ≤ -15℃, that is, the polymer matrix melting temperature is less than the hot pressing temperature, it is beneficial for the polymer matrix to remain in a molten state during hot pressing, for the zinc salt, imide lithium salt to disperse in the polymer matrix, for the polymer matrix to fully react with the zinc salt, and for the ionic conductivity of the polymer solid electrolyte membrane to be improved. The presence of polar functional groups facilitates the reaction of zinc ions with polar functional groups on the polymer chain segments, thereby slowly dissolving in the molten polymer and continuing to react to form nanoparticles.

[0048] A mass ratio between the zinc salt and the host that is too large or too small affects the smooth construction of the block structure of the polymer solid electrolyte, resulting in low cycle performance of the solid-state battery, so controlling the mass ratio of the zinc salt and the host to be (0.8-1.2):100 and hot pressing under specific parameters can effectively build the above-mentioned block structure in which the flexible chain segments and the rigid chain segments alternate with each other to form a three-dimensional network.

[0049] Illustratively, the mass ratio of the zinc salt and the host is any one of 0.8:100, 0.9:100, 1.0:100, 1.1:100, 1.2:100 or between any two values.

[0050] Pre-pressing refers to pressing the precursor into a green body at room temperature, and the precursor is a mixture of zinc salt, imide lithium salt, and polymer matrix. The present application adopts the method of hot pressing the green body formed by pre-pressing, which on the one hand facilitates the movement of zinc salt and imide lithium salt with the movement of the polymer matrix during the process of pre-pressing to form a green body, and on the other hand facilitates the uniform dispersion of zinc salt and imide lithium salt, thereby improving the performance of the polymer solid electrolyte membrane. In addition, compared with directly hot pressing the precursor, it is more conducive to shaping.

[0051] The hot pressing pressure, hot pressing temperature, and hot pressing time all affect the effective construction of the block structure in which the flexible chain segments and the rigid chain segments alternate with each other to form a three-dimensional network, so selecting a hot pressing pressure of 10-15 MPa, a hot pressing temperature of 100-120℃, and hot pressing for 35-45 min under the above conditions, in combination with the selection of raw materials, is conducive to the preparation of a polymer solid electrolyte membrane with a three-dimensional network block structure, thereby effectively improving the cycle performance and other electrochemical properties of the solid-state battery.

[0052] Illustratively, the hot pressing pressure is any one of 10 MPa, 11 MPa, 12 MPa, 13 MPa, 14 MPa, 15 MPa or between any two values.

[0053] Illustratively, the hot pressing temperature is any one of 100℃, 105℃, 110℃, 115℃, 120℃ or between any two values.

[0054] Exemplarily, the hot-pressing time is any value in 35 min, 37 min, 39 min, 40 min, 43 min, 45 min or between any two values. The hot-pressing time can be adjusted within the above range according to the selection of the specific hot-pressing pressure and hot-pressing temperature.

[0055] In summary, the preparation method provided by the present application is simple and controllable. By matching the specific mass ratio of raw materials with the specific hot-pressing conditions, the polymer solid electrolyte film has a block structure in which flexible segments and rigid segments alternately present a three-dimensional network. When the polymer solid electrolyte film is applied to a solid-state battery, the cycle performance of the solid-state battery can be effectively improved, and the solid-state battery has good long-term and short-term electrical performance and safety performance.

[0056] The zinc salt is used to provide zinc ions.

[0057] The zinc salt includes, but is not limited to, zinc triflate, zinc perchlorate, propineb, zinc dimethylacrylate, zinc triflimide, zinc stearate, zinc sulfide, or zinc halide, etc.

[0058] In some embodiments, the zinc salt includes zinc halide, and the zinc halide includes at least one of zinc fluoride, zinc chloride, zinc bromide, and zinc iodide.

[0059] By selecting zinc halide as the zinc salt, not only zinc ions can be provided, but also free halide ions can participate in the formation of SEI film during the first charging process of the solid-state battery, which is beneficial to improving the compactness of the SEI film and the cycle performance of the solid-state battery.

[0060] In some embodiments, the polymer matrix includes at least one of polyvinyl alcohol (PVA), polyethylene oxide (PEO), polypropylene oxide (PPO), and polybutylene oxide (PBO).

[0061] The polymer solid electrolyte film prepared by using each of the above polymer matrices applied to a solid-state battery is beneficial to improving the cycle performance of the solid-state battery.

[0062] Alternatively, the polymer matrix includes at least one of polyethylene oxide (PEO), polypropylene oxide (PPO), and polybutylene oxide (PBO). The above selection is beneficial to further improving the cycle performance of the solid-state battery.

[0063] In some embodiments, the molecular weight of the polymer matrix is 10,000-18,000.

[0064] Within the above range, the polymer solid electrolyte film prepared is applied to a solid-state battery, and the solid-state battery has better cycle performance.

[0065] Exemplarily, the molecular weight of the polymer matrix is any one of 10000, 11000, 12000, 13000, 14000, 15000, 16000, 17000, 18000 or between any two values.

[0066] In some embodiments, the molecular weight of the polymer matrix is 12000-15000.

[0067] The polymer solid electrolyte film prepared in the above range is applied to a solid-state battery, which is beneficial to further improve the cycle performance of the solid-state battery.

[0068] Exemplarily, the molecular weight of the polymer matrix is any one of 12000, 12500, 13000, 13500, 14000, 14500, 15000 or between any two values.

[0069] In some embodiments, the lithium imide salt includes but is not limited to at least one of lithium bisfluorosulfonylimide and lithium bis-trifluoromethanesulfonimide.

[0070] In some embodiments, the lithium imide salt is lithium bis-trifluoromethanesulfonimide.

[0071] The polymer solid electrolyte film prepared in the above lithium bis-trifluoromethanesulfonimide is applied to a solid-state battery, which is beneficial to improve the cycle performance of the solid-state battery.

[0072] In some embodiments, the mass ratio of the lithium imide salt to the polymer matrix in the main body is (25-35):(65-75).

[0073] The polymer solid electrolyte film prepared in the above ratio is applied to a solid-state battery, which has good cycle performance.

[0074] Exemplarily, the mass ratio of the lithium imide salt to the polymer matrix is any one of 25:75, 28:72, 30:70, 33:67, 35:65 or between any two values.

[0075] The organic solvent is used to dissolve the polymer matrix.

[0076] In some embodiments, the organic solvent includes at least one of anisole, dichloroethane, chloroform, dimethylformamide.

[0077] The above organic solvents have good solubility for the polymer matrix, which is beneficial to the uniform mixing of the zinc salt, the lithium imide salt and the polymer matrix.

[0078] In some embodiments, the pre-press forming includes: pressing under the condition of 10Mpa-15MPa for 10min-15min.

[0079] Through the above operation, it is beneficial to press the precursor into a blank, and beneficial to subsequent heat pressing and shaping.

[0080] Exemplarily, the pressure of the pre-pressing forming is any one of 10 Mpa, 11 Mpa, 12 Mpa, 13 Mpa, 14 Mpa, 15 Mpa or between any two values, and the time of the pre-pressing forming is any one of 10 min, 11 min, 12 min, 13 min, 14 min, 15 min or between any two values.

[0081] The step of mixing the zinc salt, the lithium imide salt, the polymer matrix and the organic solvent for dissolving the polymer matrix can be that the zinc salt, the lithium imide salt and the polymer matrix are added into the organic solvent together and stirred and mixed, or the polymer matrix can be dissolved in the organic solvent first and then mixed with the zinc salt and the lithium imide salt.

[0082] In some embodiments, the step of mixing comprises:

[0083] The polymer matrix is dissolved in the organic solvent to obtain a polymer solution.

[0084] The zinc salt and the lithium imide salt are mixed with the polymer solution under stirring.

[0085] The method of first dissolving the polymer matrix in the organic solvent and then mixing the zinc salt and the lithium imide salt is beneficial to the uniform mixing of the three, and is beneficial to the uniform distribution of the components in the obtained precursor, thereby improving the uniformity of the reaction between the zinc ions and the polymer matrix in the subsequent heat pressing reaction process and improving the performance of the polymer solid electrolyte membrane.

[0086] After mixing, the precursor is dried, and it can be understood that the drying temperature should be less than the lowest heat pressing temperature, and the zinc ions and the polymer matrix do not chemically react during the drying process. Therefore, the drying can be vacuum drying, and the temperature of the vacuum drying is less than the lowest heat pressing temperature.

[0087] In some embodiments, the drying is low-temperature vacuum drying at 50°C to 80°C.

[0088] Through the above low-temperature vacuum drying method, on the basis of achieving the purpose of drying, chemical reactions between the components and air or between the components, such as zinc ions and polymer matrix, can be effectively avoided, which is beneficial to improving the performance of the polymer solid electrolyte membrane.

[0089] Exemplarily, the temperature of the low-temperature vacuum drying is any one of 50°C, 60°C, 70°C, 80°C or between any two values.

[0090] The application further provides a polymer solid-state electrolyte film prepared by the preparation method.

[0091] The polymer solid-state electrolyte film has a block structure in which flexible segments and rigid segments are alternately present in a three-dimensional network, and when applied to a solid-state battery, the polymer solid-state electrolyte film can effectively improve the cycle performance of the solid-state battery and enable the solid-state battery to have good long-term and short-term electrical performance and safety performance.

[0092] Exemplarily, the polymer solid-state electrolyte film has a thickness of 1 μm to 1000 μm.

[0093] The application further provides a polymer solid-state electrolyte film, and the solid-state electrolyte film has a block structure in which rigid segments and flexible segments are alternately connected to present a three-dimensional network.

[0094] The rigid segments are crosslinked bodies with rigidity, which are formed by crosslinking a plurality of polymer molecular chains through coordination reaction between the zinc ion-containing aggregate particles and the polar functional groups on the polymer matrix, and the polar functional groups include -OH and / or -C-O-C-.

[0095] The flexible segments are free polymer molecular chains.

[0096] The polymer solid-state electrolyte with the block structure not only constructs a stable lithium ion transmission network by virtue of the unique structure of the alternately arranged rigid and flexible segments, effectively inhibits the generation of battery capacity attenuation and lithium dendrites, but also captures part of TFSI- as crosslinking points, so that more Li 2+ In addition to serving as crosslinking points, the zinc ion-containing aggregate particles can also capture part of TFSI-. + The lithium ions can migrate on the polymer chains, thereby improving the electrical conductivity, and the polymer solid-state electrolyte has good mechanical properties and certain ductility, and can effectively prevent the destruction of the electrolyte structure caused by external factors or lithium dendrites.

[0097] That is, the polymer solid-state electrolyte film can effectively improve the cycle performance of the solid-state battery when applied to the solid-state battery, and enable the solid-state battery to have good long-term and short-term electrical performance and safety performance.

[0098] The application further provides a solid-state battery comprising the polymer solid-state electrolyte film.

[0099] The solid-state battery is a lithium battery, and generally includes a positive electrode sheet, a negative electrode sheet and a polymer solid-state electrolyte film. During the charging and discharging process of the solid-state battery, active lithium ions are embedded and extracted between the positive electrode sheet and the negative electrode sheet. The polymer solid-state electrolyte film plays a role in conducting lithium ions between the positive electrode sheet and the negative electrode sheet.

[0100] The solid-state battery can be a full battery or a half battery. The outer package of the solid-state battery can be a hard shell, such as a hard plastic shell, an aluminum shell, a steel shell, or the like, or can be a soft package, such as a bag-type soft package. The material of the soft package can be plastic, and as the plastic, polypropylene, polybutylene terephthalate, and polybutylene succinate can be listed.

[0101] The shape of the solid-state battery is not particularly limited in the present application, and the solid-state battery can be cylindrical, square, or any other shape.

[0102] The present application also provides a power-using device comprising the solid-state battery.

[0103] The solid-state battery can be used as a power source of the power-using device or as an energy storage unit of the power-using device. The power-using device can be, but is not limited to, a mobile device, an electric vehicle, an electric train, a ship and a satellite, an energy storage system, or the like; wherein the mobile device can include, but is not limited to, at least one of a mobile phone, a notebook computer, or the like; the electric vehicle can include, but is not limited to, at least one of a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, an electric bicycle, an electric scooter, an electric golf cart, an electric truck, or the like.

[0104] The polymer solid-state electrolyte film, the preparation method thereof, the solid-state battery, and the power-using device of the present application are further described in detail below in conjunction with embodiments.

[0105] Embodiment 1

[0106]

Polymer solid-state electrolyte film

[0107] 1) Take 50 g of polyethylene oxide (PEO) polymer with a molecular weight of 13000, and place it in 200 g of anisole. Stir at 300 r / min for 50 min to fully dissolve the PEO and obtain a polymer solution;

[0108] 2) Take 0.8 g of zinc fluoride (ZnF2) and 22 g of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), and place them in the above polymer solution. Stir at 400 r / min for 18 min to fully mix the polymer matrix, lithium salt, and crosslinking agent, and obtain a polymer precursor solution.

[0109] 3) Place the polymer precursor solution obtained in step 2) in a vacuum oven, and vacuumize to -0.1 MPa. Dry at 60°C for 12 h until the solvent is completely removed, and obtain a uniformly mixed precursor of PEO, LiTFSI, and ZnF2.

[0110] 4) Place the precursor in a 100 μm deep mold, and press at 25°C at 13 MPa for 12 min to obtain a thin and uniform green body;

[0111] 5) Put the blank obtained in step 4) into a mold with a depth of 100 μm, place it in a double-plate hot press, adjust the temperature of the upper and lower plates to 110°C, and after the temperature of the hot press is stabilized, hot press at a pressure of 13 MPa for 40 min, and after the polymer film obtained by hot pressing is taken out, naturally cool it to 25°C to obtain a block polymer polymer solid electrolyte film with a stable crosslinked network.

[0112]

Button-type semi-solid-state battery

[0113] LiNi 0.9 Co 0.05 Mn 0.05 , a conductive agent SP, and a binder PVDF are mixed in a ratio of 90:5:5, homogenized in an NMP system, the slurry is coated on an aluminum foil, and then dried and rolled to obtain a LiNi 0.9 Co 0.05 Mn 0.05 pole piece.

[0114] Take a lithium sheet as a negative pole piece, a LiNi 0.9 Co 0.05 Mn 0.05 pole piece as a positive pole piece, and a foam nickel as a buffer gasket, and assemble the above block polymer polymer solid electrolyte to obtain a button-type semi-solid-state battery.

[0115] Example 2

[0116] The difference from Example 1 is only that the polymer matrix PEO is replaced by polyvinyl alcohol (PVA), and the rest of the component content, polymerization degree, preparation conditions, and other parameters are the same as in Example 1.

[0117] Example 3

[0118] The difference from Example 1 is only that the polymer matrix PEO is replaced by polypropylene oxide (PPO), and the rest of the component content, polymerization degree, preparation conditions, and other parameters are the same as in Example 1.

[0119] Example 4

[0120] The difference from Example 1 is only that the polymer matrix PEO is replaced by polybutylene oxide (PBO), and the rest of the component content, polymerization degree, preparation conditions, and other parameters are the same as in Example 1.

[0121] Example 5

[0122] The difference from Example 1 is only that zinc fluoride is replaced by zinc chloride (ZnCl2), and the rest of the component content, polymerization degree, preparation conditions, and other parameters are the same as in Example 1.

[0123] Example 6

[0124] The difference from Example 1 is only that zinc fluoride is replaced by zinc bromide (ZnBr2), and the rest of the component content, polymerization degree, preparation conditions and other parameters are the same as those of Example 1.

[0125] Example 7

[0126] The difference from Example 1 is only that the crosslinking agent is changed to zinc bromide (ZnI2), and the rest of the component content, polymerization degree, preparation conditions and other parameters are the same as those of Example 1.

[0127] Example 8

[0128] The difference from Example 1 is only that the hot-pressing temperature in step 5) is changed to 120℃, the hot-pressing pressure is 13MPa, and the hot-pressing time is 40min, and the rest of the component content, polymerization degree, preparation conditions and other parameters are the same as those of Example 1.

[0129] Example 9

[0130] The difference from Example 1 is only that the hot-pressing pressure in step 5) is changed to 15MPa, the hot-pressing temperature is set to 110℃, and the hot-pressing time is 40min, and the rest of the component content, polymerization degree, preparation conditions and other parameters are the same as those of Example 1.

[0131] Example 10

[0132] The difference from Example 1 is only that the hot-pressing time in step 5) is changed to 45min, the hot-pressing temperature is set to 110℃, and the hot-pressing pressure is 13MPa, and the rest of the component content, polymerization degree, preparation conditions and other parameters are the same as those of Example 1.

[0133] Example 11

[0134] The difference from Example 1 is only that the molecular weight of PEO is 10000, and the rest of the component content, polymerization degree, preparation conditions and other parameters are the same as those of Example 1.

[0135] Example 12

[0136] The difference from Example 1 is only that the molecular weight of PEO is 18000, and the rest of the component content, polymerization degree, preparation conditions and other parameters are the same as those of Example 1.

[0137] Comparative Example 1

[0138] The difference from Example 1 is only that the amount of zinc fluoride added is replaced by 0.36g, and the rest of the component content, polymerization degree, preparation conditions and other parameters are the same as those of Example 1.

[0139] Comparative Example 2

[0140] The difference between it and Example 1 is only that the amount of zinc fluoride is replaced by 1.08 g, and the rest of the component content, degree of polymerization, preparation conditions and other parameters are the same as Example 1.

[0141] Comparative Example 3

[0142] The difference between it and Example 1 is only that the hot pressing time is adjusted to 30 min, and the rest of the component content, degree of polymerization, preparation conditions and other parameters are the same as Example 1.

[0143] Comparative Example 4

[0144] The difference between it and Example 1 is only that the hot pressing time is adjusted to 50 min, and the rest of the component content, degree of polymerization, preparation conditions and other parameters are the same as Example 1.

[0145] Comparative Example 5

[0146] The difference between it and Example 1 is only that the hot pressing temperature is adjusted to 80℃, and the rest of the component content, degree of polymerization, preparation conditions and other parameters are the same as Example 1.

[0147] Comparative Example 6

[0148] The difference between it and Example 1 is only that the hot pressing temperature is adjusted to 150℃, and the rest of the component content, degree of polymerization, preparation conditions and other parameters are the same as Example 1.

[0149] Comparative Example 7

[0150] The difference between it and Example 1 is only that the lithium bis-trifluoromethanesulfonimide is changed to lithium hexafluorophosphate (LiPF6), and the rest of the component content, degree of polymerization, preparation conditions and other parameters are the same as Example 1.

[0151] Test Example 1

[0152] The performance of the polymer solid electrolyte film and the button-type solid-state battery prepared in each example and comparative example is tested respectively, and the specific test method includes:

[0153]

Short-term power test

[0154]

Rate performance 2C / 0.2C

[0155]

Cycle number

[0156]

Capacity retention rate

[0157]

Ionic conductivity

[0158]

Young's modulus

[0159] The results are shown in Table 1.

[0160] Table 1 Test Results

[0161]

[0162] According to Table 1, the polymer solid electrolyte film provided by the application has good mechanical properties and ionic conductivity, and the solid-state battery using the polymer solid electrolyte film has good long-term and short-term electrical performance and safety performance, especially the cycle number corresponding to 80% SOH of the solid-state battery is improved, and the cycle life is improved.

[0163] According to the embodiment 1, the comparative examples 1-2, it can be seen that the mass ratio between the zinc salt and the host is too large or too small, which affects the smooth construction of the block structure of the polymer solid electrolyte, resulting in low cycle performance of the solid-state battery. Controlling the mass ratio of the zinc salt and the host to be (0.8-1.2):100 and heat pressing under specific parameters can effectively build the block structure in which the flexible segment and the rigid segment present a three-dimensional network alternately, thereby effectively improving the cycle number corresponding to 80% SOH of the solid-state battery.

[0164] According to the embodiment 1, the comparative examples 3-6, it can be seen that the heat pressing pressure, the heat pressing temperature and the heat pressing time all affect the effective construction of the block structure in which the flexible segment and the rigid segment present a three-dimensional network alternately. The present application selects the heat pressing pressure to be 10-15 MPa, the heat pressing temperature to be 100-120°C and the heat pressing time to be 35-45 min, which is beneficial to the preparation of the polymer solid electrolyte film having the three-dimensional network block structure, thereby effectively improving the cycle performance and other electrochemical properties of the solid-state battery.

[0165] According to the embodiment 1, the comparative example 7, it can be seen that the selection of the lithium salt will significantly affect the ionic conductivity of the polymer solid electrolyte film and the performance of the final battery. The selection of the imide lithium salt as the electrolyte salt in the polymer solid electrolyte film of the present application is beneficial to improving the ionic conductivity of the polymer solid electrolyte film and the cycle life of the battery.

[0166] In summary, the polymer solid electrolyte film provided by the present application has good mechanical properties and ionic conductivity. When the polymer solid electrolyte film is applied to the solid-state battery, the cycle performance of the solid-state battery can be effectively improved, and the solid-state battery has good long-term and short-term electrical performance and safety performance.

[0167] The above is only a specific embodiment of the present application and is not used to limit the present application. For those skilled in the art, the present application can have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preparing a polymer solid-state electrolyte membrane, wherein, The method comprises the following steps: mixing a zinc salt, a lithium imide salt, a polymer matrix and an organic solvent used for dissolving the polymer matrix, drying to obtain a precursor; after pre-pressing the precursor, the obtained blank is hot-pressed under the condition of a hot-pressing pressure of 10-15 MPa and a hot-pressing temperature of 100-120 ℃ for 35-45 min; wherein the decomposition temperature of the lithium imide salt is greater than the hot-pressing temperature, the melting temperature of the polymer matrix is ≤100 ℃ and the glass transition temperature is ≤-15 ℃, the polymer matrix contains a polar functional group, the polar functional group includes -OH and / or -C-O-C-, the lithium imide salt and the polymer matrix are used as a host, and the mass ratio of the zinc salt to the host is (0.8-1.2):

100.

2. The production method according to claim 1, wherein The zinc salt includes a zinc halide, and the zinc halide includes at least one of zinc fluoride, zinc chloride, zinc bromide and zinc iodide.

3. The production method according to claim 1, wherein, The polymer matrix includes at least one of polyvinyl alcohol, polyethylene oxide, polypropylene oxide and polybutylene oxide.

4. The production method according to claim 1, wherein The molecular weight of the polymer matrix is 10,000-18,000.

5. The production method according to claim 1, wherein The molecular weight of the polymer matrix is 12,000-15,000.

6. The production method according to claim 1, wherein The lithium imide salt includes lithium bis-trifluoromethanesulfonimide.

7. The process of any one of claims 1 to 6, wherein, In the host, the mass ratio of the lithium imide salt to the polymer matrix is (25-35):(65-75).

8. The process of any one of claims 1 to 6, wherein, The organic solvent includes at least one of anisole, dichloroethane, chloroform and dimethylformamide.

9. The process of any one of claims 1 to 6, wherein, The pre-pressing includes pressing under the condition of 10-15 MPa for 10-15 min.

10. The process of any one of claims 1 to 6, wherein, The mixing step includes: dissolving the polymer matrix in the organic solvent to obtain a polymer solution; mixing the zinc salt, the lithium imide salt and the polymer solution under stirring.

11. The process of any one of claims 1 to 6, wherein, The drying is low-temperature vacuum drying at 50-80 ℃.

12. A polymer solid-state electrolyte membrane, wherein, The solid-state electrolyte film is prepared by the preparation method in any one of claims 1-11.

13. A polymer solid-state electrolyte membrane, wherein, The solid-state electrolyte film has a block structure in which rigid segments and flexible segments are alternately connected to present a three-dimensional network structure; wherein the rigid segments are crosslinked bodies with rigidity formed by crosslinking a plurality of polymer molecular chains through coordination reaction of the zinc ion-containing aggregate particles with the polar functional groups on the polymer matrix, the zinc ion-containing aggregate particles are crosslinking points with a nanometer-micrometer scale, and the polar functional groups include -OH and / or -C-O-C-; the flexible segments are free polymer molecular chains.

14. A solid-state battery, wherein, The solid-state battery includes the polymer solid-state electrolyte film in claim 12 or 13.

15. An electrical device, comprising: The solid-state battery includes the solid-state battery in claim 14.

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