Polyurethane-plastic crystal electrolyte, preparation method thereof and solid-state battery

Abstract

The invention discloses a polyurethane-plastic crystal electrolyte, a preparation method thereof and a solid-state battery, and belongs to the technical field of lithium ion batteries. The electrolyte is a solid electrolyte and comprises a polyurethane framework and a plastic crystal mixed filler, polyurethane comprises thermoplastic polyurethane rubber and a polyurethane adhesive, the thermoplastic polyurethane rubber provides a basic framework, a three-dimensional penetrating network is formed through in-situ polymerization of the polyurethane adhesive, and the framework structure of polyurethane is further strengthened. The plastic crystal filler is filled in the three-dimensional network skeleton structure in a mode of mixing ionic plastic crystals and non-ionic plastic crystals. Due to the flexible structure of polyurethane, good flexibility is provided for the solid electrolyte, and due to the matching combination of nonionic plastic crystals and ionic plastic crystals, the stability of negative electrode metal lithium is effectively improved; the preparation method is simple and efficient, the assembled solid-state battery is excellent in mechanical strength, high in ionic conductivity and wide in electrochemical stability window, and lithium dendrites can be remarkably inhibited.

Description

Technical Field

[0001] The present invention belongs to the technical field of lithium-ion batteries, and in particular relates to a polyurethane-plastic crystal electrolyte and a preparation method thereof, and a solid-state battery. Background Art

[0002] The surge in demand for low-cost, green, and efficient power sources has provided a major impetus for the development of next-generation energy storage devices with high energy density, long cycle life, and high safety. Among them, all-solid-state batteries (ASSBs) can provide better performance than conventional liquid batteries, but their cycling performance largely depends on the performance of the solid electrolyte, a key component located between the positive and negative electrode layers.

[0003] Plastic crystals represent a possible intermediate stage between ordered crystals and liquid phases or melts, exhibiting long-range order but short-range disorder. These highly disordered compounds (primarily organic compounds) contain randomly oriented molecules that form highly symmetrical sublattices within the crystal lattice. The molecules in these so-called rotor phases interact through weak long-range forces, resulting in high compressibility and deformability; hence, they are termed "plastic." Traditional plastic crystals can be categorized as molecular crystals or ionic crystals, consisting of discrete molecules or ions located at defined lattice positions, respectively. They represent a promising source of solid electrolyte materials. They include non-ionic and ionic plastic crystals. Non-ionic plastic crystals are prepared by adding lithium salts to organic materials at room temperature, but they exhibit side reactions with the lithium metal anode. Ionic plastic crystals, on the other hand, have nitrogen-containing heterocyclic organic compounds as cations and polyanions as anions. Compared to non-ionic plastic crystals, conventional polymer electrolytes such as PEO not only have low ionic conductivity but also poor mechanical strength, which compromises battery safety. Summary of the Invention

[0004] One of the purposes of the present invention is to provide a polyurethane-plastic crystal electrolyte to solve the problems of poor mechanical strength and low ionic conductivity of existing solid electrolytes;

[0005] The second object of the present invention is to provide a method for preparing a polyurethane-plastic crystal electrolyte;

[0006] A third object of the present invention is to provide a solid-state battery comprising a polyurethane-plastic crystal electrolyte.

[0007] The purpose of the present invention can be achieved through the following technical solutions:

[0008] In a first aspect, the present invention provides a polyurethane-plastic crystal electrolyte, comprising a polyurethane skeleton and a plastic crystal mixture, wherein the polyurethane skeleton is polymerized from a polyurethane prepolymer to provide a three-dimensional network structure, and the plastic crystal mixture is filled therein;

[0009] The weight ratio of the polyurethane prepolymer to the plastic crystal mixture is 1:(5-15).

[0010] As a further solution of the present invention, the plastic crystal mixture is composed of non-ionic plastic crystal and ionic plastic crystal in a weight ratio of (0.5-2):1.

[0011] Furthermore, the non-ionic plastic crystal is composed of succinonitrile and lithium salt in a weight ratio of (2-4):1; the ionic plastic crystal is N-ethyl-N-methylbis(fluorosulfonyl)imide pyrrole salt.

[0012] Furthermore, the lithium salt is any one of lithium hexafluorophosphate, lithium bis(trifluoromethanesulfonyl imide), lithium bis(fluorosulfonyl imide), and lithium perchlorate.

[0013] As a further embodiment of the present invention, the method for preparing the polyurethane prepolymer comprises the following steps:

[0014] S1: Add polyisocyanate and blocking agent into a reaction kettle, and react at 40-100°C under nitrogen protection for 4-10 hours to obtain blocked polyisocyanate;

[0015] S2: Adding polyether polyol to the blocked polyisocyanate, polymerizing at 50-180°C for 20-40 minutes to obtain a polyurethane adhesive;

[0016] S3: Add the polyurethane adhesive to the thermoplastic polyurethane rubber and stir to mix evenly to obtain a polyurethane prepolymer.

[0017] First, a blocked isocyanate intermediate is prepared, and then polyether polyol is introduced for chain extension. This can precisely control the molecular weight and branching degree of the prepolymer to avoid gelation. Thermoplastic polyurethane rubber is added as a plasticizer to improve processing performance, and the adhesive provides cross-linking points. The entanglement of the plasticizer matrix molecular chains is used to improve the rheological properties of the system. Flexible chain segments are further introduced to improve the adhesion between the electrolyte and the interface and reduce the interface impedance.

[0018] Furthermore, in S1, the molar ratio of the blocking agent to the -NCO group in the polyisocyanate is (1-1.2):1.

[0019] Furthermore, in S1, the blocking agent is any one of phenol, tert-butyl alcohol, diethyl malonate, and caprolactam; the polyisocyanate is any one of toluene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, triphenylmethane triisocyanate, and dimethyltriphenylmethane tetraisocyanate.

[0020] Furthermore, in S2, the weight ratio of blocked polyisocyanate to polyether polyol is (2-5):1.

[0021] Furthermore, in S2, the polyether polyol is any one of polyoxypropylene glycol, polyoxypropylene triol, and polytetramethylene glycol.

[0022] Furthermore, in S3, the weight ratio of the thermoplastic polyurethane rubber to the polyurethane adhesive is (1-10):1.

[0023] In a second aspect, the present invention provides a method for preparing a polyurethane-plastic crystal electrolyte, comprising the following steps:

[0024] Ionic plastic crystal is added to non-ionic plastic crystal, mixed evenly, to obtain a plastic crystal mixture; polyurethane prepolymer is then added and mixed evenly, and the obtained electrolyte precursor is cured at a temperature of 50-100° C. for 0.5-3 hours, and polymerized to obtain a polyurethane-plastic crystal electrolyte.

[0025] Lithium salt is dissolved in succinonitrile and forms Li + The transmission channel is then filled with ionic plastic crystals (N-ethyl-N-methylbis(fluorosulfonyl)imide pyrrolidone) to form a plastic crystal phase in collaboration with succinonitrile to promote ion migration. The polyurethane prepolymer is cured to form a three-dimensional cross-linked network to wrap the plastic crystal and lithium salt, providing solid support to prevent the plastic crystal from flowing and adapting to the volume changes during battery charging and discharging. The compatibility of the plastic crystal phase with polyurethane reduces phase separation and ensures the continuity of the ion channel.

[0026] In a third aspect, the present invention provides a solid-state battery comprising the polyurethane-plastic crystal electrolyte described in the first aspect.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] 1. The present invention provides a polyurethane-plastic crystal electrolyte for use in solid-state batteries. The electrolyte is a solid electrolyte comprising a polyurethane skeleton and a plastic crystal mixed filler, wherein the polyurethane comprises thermoplastic polyurethane rubber and polyurethane adhesive. The thermoplastic polyurethane rubber provides the basic skeleton, and the polyurethane adhesive is in situ polymerized to form a three-dimensional penetrating network, thereby further strengthening the skeleton structure of the polyurethane. The plastic crystal filler is a mixture of ionic plastic crystals and non-ionic plastic crystals, and is filled in the three-dimensional network skeleton structure. Due to the flexible structure of the polyurethane, it provides better flexibility for the solid electrolyte. The combination of non-ionic plastic crystals and ionic plastic crystals effectively improves the stability to the negative electrode metal lithium. In addition, its preparation method is simple and efficient, and can be applied industrially.

[0029] 2. The present invention utilizes the prepared polyurethane-plastic crystal electrolyte to further prepare a solid-state battery. After the positive electrode, separator, and negative electrode are assembled into a battery, the precursor of the polyurethane-plastic crystal electrolyte is added to the battery and heated and cured at 50-100°C. During the curing process, the precursor will be in situ cured between the positive electrode and the negative electrode to form a polyurethane-plastic crystal solid electrolyte electrolyte layer, which is used to block the positive and negative electrodes and for the transmission of lithium ions. The solid-state battery finally prepared has excellent mechanical strength, high ionic conductivity, a wide electrochemical stability window, and can significantly inhibit lithium dendrites. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The present invention will be further described below with reference to the accompanying drawings.

[0031] Figure 1 This is a comparison chart of tensile curves of the electrolyte membranes obtained by curing in Preparation Example 1 of the present invention and in the comparative preparation example;

[0032] Figure 2 1 is a comparison of AC impedance spectra of solid-state batteries including corresponding polyurethane-plastic crystal electrolytes in Example 1 of the present invention and Comparative Example 1;

[0033] Figure 3 It is a linear sweep voltammetry comparison diagram of the solid-state battery including the corresponding polyurethane-plastic crystal electrolyte in Example 1 of the present invention and Comparative Example 1. DETAILED DESCRIPTION

[0034] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0035] Obviously, the following descriptions are merely some examples or embodiments of the present application. Those skilled in the art can apply the present application to other similar scenarios without inventive effort. Furthermore, it is also understood that, although the effort involved in such a development process may be complex and lengthy, for those skilled in the art related to the content disclosed in the present application, changes in design, manufacturing, or production based on the technical content disclosed in the present application are merely conventional technical means and should not be construed as an insufficiency of the content disclosed in the present application.

[0036] However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters or repeated descriptions of substantially identical structures may be omitted. This is to avoid unnecessary redundancy in the following description and to facilitate understanding by those skilled in the art. Furthermore, the following description is provided to enable those skilled in the art to fully understand this application and is not intended to limit the subject matter recited in the claims.

[0037] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution, and all technical features and optional technical features of the present application can be combined with each other to form a new technical solution.

[0038] The positive electrode sheet, negative electrode sheet, and separator used in the solid-state batteries involved in the following embodiments and comparative examples are as follows:

[0039] Positive electrode sheet: 97 parts by weight of ternary material (523), 1.5 parts by weight of conductive carbon black, 1 part by weight of adhesive PVDF, 0.5 parts by weight of carbon nanotubes and 100 parts by weight of solvent NMP were mixed for 24 hours to prepare a positive electrode slurry, which was then coated on the surface of aluminum foil, dried at 100° C. for 24 hours, and then compacted to obtain a positive electrode slurry;

[0040] Negative electrode sheet: 97 parts by weight of graphite negative electrode material, 1.5 parts by weight of conductive carbon black, 1 part by weight of LA136 binder, 0.5 parts by weight of sodium carboxymethyl cellulose, and 100 parts by weight of water were stirred and evenly mixed, coated on the surface of copper foil, dried at 120°C for 24 hours, and then compacted;

[0041] Isolation: non-woven fabric;

[0042] In order to facilitate comparison of battery performance, the following examples and comparative examples use the above-mentioned positive electrode sheets, negative electrode sheets and separators; those skilled in the art can adjust the formula according to specific circumstances.

[0043] Preparation Example 1

[0044] This preparation example provides a method for preparing a precursor of a polyurethane-plastic crystal electrolyte, comprising the following steps:

[0045] (1) Preparation of polyurethane prepolymer:

[0046] S1: Toluene diisocyanate and phenol are added to a reaction kettle in a molar ratio of toluene to -NCO groups in toluene diisocyanate of 1.1:1; the reactants are reacted under nitrogen protection at 80°C for 6 hours to obtain phenol-blocked toluene diisocyanate;

[0047] S2: Add 1 g of polyoxypropylene glycol-200 to 2 g of phenol-blocked toluene diisocyanate and polymerize at 170°C for 30 min to obtain a polyurethane adhesive.

[0048] S3: Add the polyurethane adhesive to 3 g of thermoplastic polyurethane rubber (WHT-1570, Yantai Wanhua) and stir to mix evenly to obtain a polyurethane prepolymer;

[0049] (2) Preparation of polyurethane-plastic electrolyte precursor:

[0050] 3.33 g of lithium hexafluorophosphate was added to 6.67 g of succinonitrile, and the mixture was stirred and dissolved to obtain a non-ionic plastic crystal. 20 g of N-ethyl-N-methylbis(fluorosulfonyl)imide pyrrole salt was then added and mixed evenly to obtain a plastic crystal mixture. A polyurethane prepolymer was then added and mixed evenly to obtain a precursor.

[0051] Preparation Example 2

[0052] This preparation example provides a method for preparing a precursor of a polyurethane-plastic crystal electrolyte, comprising the following steps:

[0053] (1) Preparation of polyurethane prepolymer:

[0054] S1: adding diphenylmethane diisocyanate and phenol into a reaction kettle in a molar ratio of phenol to -NCO groups in diphenylmethane diisocyanate of 1.1:1; reacting the reactants under nitrogen protection at 90°C for 6 hours to obtain phenol-blocked diphenylmethane diisocyanate;

[0055] S2: Add 1 g of polyoxypropylene triol-600 to 5 g of phenol-blocked diphenylmethane diisocyanate and polymerize at 165°C for 30 min to obtain a polyurethane adhesive.

[0056] S3: Add the polyurethane adhesive to 6 g of thermoplastic polyurethane rubber (Yantai Wanhua, WHT-1570) and stir to mix evenly to obtain a polyurethane prepolymer;

[0057] (2) Preparation of polyurethane-plastic electrolyte precursor:

[0058] 6.67 g of lithium bis(trifluoromethanesulfonyl imide) was added to 13.33 g of succinonitrile, and the mixture was stirred and dissolved to obtain a non-ionic plastic crystal. 40 g of N-ethyl-N-methylbis(fluorosulfonyl imide)pyrrole salt was then added and mixed evenly to obtain a plastic crystal mixture. A polyurethane prepolymer was then added and mixed evenly to obtain a precursor.

[0059] Preparation Example 3

[0060] This preparation example provides a method for preparing a precursor of a polyurethane-plastic crystal electrolyte, comprising the following steps:

[0061] (1) Preparation of polyurethane prepolymer:

[0062] S1: Triphenylmethane triisocyanate and diethyl malonate were added to a reaction kettle in a molar ratio of diethyl malonate to -NCO groups in triphenylmethane triisocyanate of 1.1:1; the reactants were reacted under nitrogen protection at 80°C for 6 hours to obtain diethyl malonate-blocked triphenylmethane triisocyanate;

[0063] S2: Add 1 g of polyoxypropylene triol-600 to 5 g of diethyl malonate-blocked triphenylmethane triisocyanate, and polymerize at 125°C for 30 min to obtain a polyurethane adhesive;

[0064] S3: Add the polyurethane adhesive to 6 g of thermoplastic polyurethane rubber (Bai Ling New Materials, 55-98A) and stir to mix evenly to obtain a polyurethane prepolymer;

[0065] (2) Preparation of polyurethane-plastic electrolyte precursor:

[0066] 20 g of lithium bis(trifluoromethanesulfonyl imide) was added to 60 g of succinonitrile, stirred and dissolved to obtain a non-ionic plastic crystal, and then 40 g of N-ethyl-N-methylbis(fluorosulfonyl imide)pyrrole salt was added and mixed evenly to obtain a plastic crystal mixture; then a polyurethane prepolymer was added and mixed evenly to obtain a precursor.

[0067] Preparation Example 4

[0068] This preparation example provides a method for preparing a precursor of a polyurethane-plastic crystal electrolyte, comprising the following steps:

[0069] (1) Preparation of polyurethane prepolymer:

[0070] S1: Dimethyltriphenylmethane tetraisocyanate and caprolactam are added to a reaction kettle in a molar ratio of caprolactam to -NCO groups in dimethyltriphenylmethane tetraisocyanate of 1.1:1; the reactants are reacted under nitrogen protection at 100°C for 6 hours to obtain caprolactam-blocked dimethyltriphenylmethane tetraisocyanate;

[0071] S2: Add 1 g of polyoxypropylene triol-600 to 5 g of diethyl malonate-blocked triphenylmethane triisocyanate, and polymerize at 180°C for 30 min to obtain a polyurethane adhesive;

[0072] S3: Add the polyurethane adhesive to 30 g of thermoplastic polyurethane rubber (Bayer U-95AI 20) and stir to mix evenly to obtain a polyurethane prepolymer;

[0073] (2) Preparation of polyurethane-plastic electrolyte precursor:

[0074] 60 g of lithium hexafluorophosphate was added to 180 g of succinonitrile, and the mixture was stirred and dissolved to obtain a non-ionic plastic crystal. 120 g of N-ethyl-N-methylbis(fluorosulfonyl)imide pyrrole salt was then added and mixed evenly to obtain a plastic crystal mixture. A polyurethane prepolymer was then added and mixed evenly to obtain a precursor.

[0075] Preparation Example 5

[0076] This preparation example provides a method for preparing a precursor of a polyurethane-plastic crystal electrolyte, comprising the following steps:

[0077] (1) Preparation of polyurethane prepolymer:

[0078] S1: Hexamethylene diisocyanate and diethyl malonate were added to a reaction kettle in a molar ratio of diethyl malonate to -NCO groups in hexamethylene diisocyanate of 1.1:1; the reactants were reacted under nitrogen protection at 90°C for 6 hours to obtain diethyl malonate-blocked hexamethylene diisocyanate;

[0079] S2: Add 1 g of polyoxypropylene triol-600 to 2 g of diethyl malonate-blocked hexamethylene diisocyanate, and polymerize at 110°C for 30 min to obtain a polyurethane adhesive.

[0080] S3: Add the polyurethane adhesive to 3 g of thermoplastic polyurethane rubber (Shanghai Lianjing, 185ASM) and stir to mix evenly to obtain a polyurethane prepolymer;

[0081] (2) Preparation of polyurethane-plastic electrolyte precursor:

[0082] 5 g of lithium perchlorate was added to 10 g of succinonitrile, and the mixture was stirred and dissolved to obtain a non-ionic plastic crystal. 15 g of N-ethyl-N-methylbis(fluorosulfonyl)imide pyrrole salt was then added and mixed evenly to obtain a plastic crystal mixture. A polyurethane prepolymer was then added and mixed evenly to obtain a precursor.

[0083] Example 1

[0084] This embodiment provides a solid-state battery, which is prepared by assembling a positive electrode, a separator, and a negative electrode into a battery, adding the precursor prepared in Preparation Example 1, and heating and curing at 50° C. for 3 hours.

[0085] Example 2

[0086] This embodiment provides a solid-state battery, which is prepared by assembling a positive electrode, a separator, and a negative electrode into a battery, adding the precursor prepared in Preparation Example 2, and heating and curing at 100° C. for 0.5 h.

[0087] Example 3

[0088] This embodiment provides a solid-state battery, which is prepared by assembling a positive electrode, a separator, and a negative electrode into a battery, adding the precursor prepared in Preparation Example 3, and heating and curing at 80° C. for 3 hours.

[0089] Example 4

[0090] This embodiment provides a solid-state battery, which is prepared by assembling a positive electrode, a separator, and a negative electrode into a battery, adding the precursor prepared in Preparation Example 4, and heating and curing at 50° C. for 2 hours.

[0091] Example 5

[0092] This embodiment provides a solid-state battery, which is prepared by assembling a positive electrode, a separator, and a negative electrode into a battery, adding the precursor prepared in Preparation Example 5, and heating and curing at 70° C. for 3 hours.

[0093] Comparative Preparation Example 1

[0094] This comparative preparation example provides a preparation method for a polyurethane-plastic crystal electrolyte precursor. The difference from Preparation Example 1 is that thermoplastic polyurethane rubber is not added, and the other preparation steps and parameters remain the same.

[0095] Comparative Preparation Example 2

[0096] This comparative preparation example provides a preparation method for a polyurethane-plastic crystal electrolyte precursor. The difference from Preparation Example 1 is that 20 g of N-ethyl-N-methylbis(fluorosulfonyl)imide pyrrole salt (ionic plastic crystal) is not added, and the other preparation steps and parameters remain the same.

[0097] Comparative Example 1

[0098] This comparative example provides a solid-state battery, which is prepared by assembling a positive electrode, a separator, and a negative electrode into a battery, adding the precursor prepared in comparative preparation example 1, and heating and curing at 50° C. for 3 hours.

[0099] Comparative Example 2

[0100] This comparative example provides a solid-state battery, which is prepared by assembling a positive electrode, a separator, and a negative electrode into a battery, adding the precursor prepared in comparative preparation example 2, and heating and curing at 50° C. for 3 hours.

[0101] Performance testing:

[0102] (1) The precursors prepared in Preparation Examples 1-5 and Comparative Preparation Examples 1-2 were heated and cured at 50° C. to form films and the following properties were tested:

[0103] 1. Ionic conductivity test:

[0104] The electrolyte precursor was injected into the button cell, and the non-woven fabric was used as the separator. The two ends were made of stainless steel sheets to assemble into a stainless steel symmetrical cell (SS / SSE / SS), which was sealed and then cured. The AC impedance test was performed using an electrochemical workstation with a test frequency range of 0.01-10 6 Hz, and the test was carried out at 25 ° C. Then the ionic conductivity of the membrane was calculated by formula (1);

[0105] σ=d / (R×S) Formula (1);

[0106] Where, σ is the ionic conductivity (mS / cm), d is the thickness of the electrolyte membrane (cm), R is the in-plane resistance perpendicular to the membrane surface (Ω), and S is the effective membrane area (cm 2 ).

[0107] 2. Electrochemical window:

[0108] The electrolyte precursor was injected into a button cell, which was then assembled into a half-cell (SS / SSE / Li) using a non-woven fabric as a separator. The cells were sealed and then cured. Linear sweep voltammetry was performed using an electrochemical workstation with a voltage range of 2.5–6 V and a scan rate of 1 mV / s at 25°C.

[0109] 3. Elastic tensile test:

[0110] The solid electrolyte membrane, formed by solidification, was cut into 1 x 5 cm rectangles. It was stretched using a universal tensile testing machine at a rate of 10 mm / min until it broke. The yield point, the point where stress increase and strain are minimal, appeared. At this point, the stress and strain are elastic, respectively.

[0111] 4. Acupuncture test:

[0112] At 25°C ± 5°C, a fully charged solid-state battery is penetrated at a speed of 25mm ± 5mm / s using a high-temperature-resistant steel needle with a diameter of 5±0.5mm. The test is terminated after one hour of observation or when the maximum surface temperature of the battery drops to 10°C or below the peak temperature. Ten batteries are sampled for each test and observed for fire or explosion. If all ten batteries do not catch fire or explode, the safety performance is indicated as "safe" and a "pass" is given. If more than one battery catches fire or explodes, a "fail" is given.

[0113] The test results are shown in Table 1.

[0114] Table 1

[0115]

[0116]

[0117] Among them, the tensile curves of the electrolyte membrane obtained by curing the precursor in Preparation Example 1 and Comparative Preparation Example 1 are compared. Figure 1 shown.

[0118] (2) AC impedance test and voltammetric test were performed on the solid-state batteries of Example 1 and Comparative Example 1 including the corresponding polyurethane-plastic crystal electrolyte. Figure 2 is the AC impedance comparison spectrum, Figure 3 This is a linear sweep voltammetry comparison diagram.

[0119] From the above tests, it can be seen that, compared with Preparation Example 1 and Comparative Preparation Example 1, when the solid electrolyte contains thermoplastic polyurethane rubber, the solid electrolyte has better flexibility and elasticity, and the performance of the assembled solid-state battery is relatively good;

[0120] Comparative Preparation Example 1 and Comparative Preparation Example 2, the use of composite plastic crystals for filling in the solid electrolyte can synergistically enhance lithium ion transmission.

[0121] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "includes," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0122] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A polyurethane-plastic crystal electrolyte, characterized in that: It includes a polyurethane skeleton and a plastic crystal mixture. The polyurethane skeleton is formed by polymerization of a polyurethane prepolymer and provides a three-dimensional network structure, in which the plastic crystal mixture is filled. The weight ratio of the polyurethane prepolymer to the plastic crystal mixture is 1:(5-15).

2. The polyurethane-plastic electrolyte according to claim 1, characterized in that: The plastic crystal mixture consists of non-ionic plastic crystal and ionic plastic crystal in a weight ratio of (0.5-2):

1.

3. The polyurethane-plastic electrolyte according to claim 2, characterized in that: The non-ionic plastic crystal is composed of succinonitrile and lithium salt in a weight ratio of (2-4):1; The ionic plastic crystal is N-ethyl-N-methylbis(fluorosulfonyl)imide pyrrole salt.

4. The polyurethane-plastic electrolyte according to claim 3, characterized in that: The lithium salt is any one of lithium hexafluorophosphate, lithium bis(trifluoromethanesulfonyl)imide, lithium bis(fluorosulfonyl)imide, and lithium perchlorate.

5. The polyurethane-plastic electrolyte according to claim 1, characterized in that: The preparation method of the polyurethane prepolymer comprises the following steps: S1: Add polyisocyanate and blocking agent into a reaction kettle, and react at 40-100°C for 4-10 hours under nitrogen protection to obtain blocked polyisocyanate; S2: Adding polyether polyol to the blocked polyisocyanate, polymerizing at 50-180°C for 20-40 minutes to obtain a polyurethane adhesive; S3: Add the polyurethane adhesive to the thermoplastic polyurethane rubber and stir to mix evenly to obtain a polyurethane prepolymer.

6. The polyurethane-plastic electrolyte according to claim 5, characterized in that: In S1, the blocking agent is any one of phenol, tert-butyl alcohol, diethyl malonate, and caprolactam; the polyisocyanate is any one of toluene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, triphenylmethane triisocyanate, and dimethyltriphenylmethane tetraisocyanate.

7. The polyurethane-plastic electrolyte according to claim 5, characterized in that: In S2, the weight ratio of blocked polyisocyanate to polyether polyol is (2-5):1; The polyether polyol is any one of polyoxypropylene diol, polyoxypropylene triol and polytetramethylene glycol.

8. The polyurethane-plastic electrolyte according to claim 5, characterized in that: In S3, the weight ratio of thermoplastic polyurethane rubber to polyurethane adhesive is (1-10):

1.

9. A method for preparing a polyurethane-plastic crystal electrolyte according to claim 1, characterized in that: The following steps are involved: Ionic plastic crystal is added to non-ionic plastic crystal, mixed evenly, to obtain a plastic crystal mixture; polyurethane prepolymer is then added and mixed evenly, and the obtained electrolyte precursor is cured at a temperature of 50-100° C. for 0.5-3 hours, and polymerized to obtain a polyurethane-plastic crystal electrolyte.

10. A solid-state battery, characterized in that: Including the polyurethane-plastic crystal electrolyte according to claim 1.

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