A polyurea-based gel electrolyte, preparation method and application

Abstract

The application belongs to the field of polymer gel electrolyte, and discloses a polyurea-based gel electrolyte, a preparation method and application.The polyurea-based gel electrolyte comprises a soft segment, a hard segment and a eutectic solvent component, wherein the soft segment is a polyether amine, the hard segment is a polyisocyanate containing a benzene ring structure, and the soft segment and the hard segment are first formed into a polyurea skeleton and can be separated under the induction of the eutectic solvent.The application improves the specific composition and detailed structure of the electrolyte, uses polyether amine as the soft segment, uses polyisocyanate containing a benzene ring structure as the hard segment, and separates the soft segment and the hard segment under the induction of the eutectic solvent, so that the polyether amine and the eutectic solvent transmit ions as a functional phase, the benzene ring stacking structure formed through hydrogen bonding and pi-pi interaction serves as a reinforcing phase to maintain the mechanical stability of the electrolyte, and the separation of the functional phase and the reinforcing phase realizes the dual improvement of the electrochemical performance and the mechanical performance.

Description

Technical Field

[0001] This invention belongs to the field of polymer gel electrolytes, and more specifically, relates to a polyurea-based gel electrolyte, its preparation method, and its application. Background Technology

[0002] Lithium-ion batteries, with their advantages of light weight, large capacity, long cycle life, and environmental friendliness, are widely used in portable electronic devices, electric vehicles, and other fields. However, the electrolytes used in commercial lithium-ion batteries not only pose safety hazards but also limit further improvements in battery energy density due to their high chemical activity. The application of solid-state electrolytes holds promise for solving these problems and can be matched with electrodes with theoretically higher capacities. Solid-state electrolytes include inorganic solid-state electrolytes and polymer solid-state electrolytes. Among them, polymer solid-state electrolytes, with their excellent flexibility and diverse processing methods, are ideal solid-state electrolyte materials for lithium-ion batteries. However, polymer solid-state electrolytes suffer from problems such as low ionic conductivity. Polymer gel electrolytes containing liquid plasticizers are expected to be the first to be commercialized due to their excellent electrochemical performance, but their poor mechanical strength seriously threatens battery safety. Rational design of the microstructure of polymer materials, such as double-crosslinked network gels, can yield gel materials with excellent mechanical properties. However, the three-dimensional crosslinked network structure of polymer solid-state electrolytes is difficult to process and recycle, which contradicts the concept of sustainable development.

[0003] Non-crosslinked polyurea networks possess excellent mechanical strength and good chemical stability. The superior performance of polyurea stems from the microphase separation structure formed by the different chemical polarities of its soft and hard segments. The hard segment aggregates act as physical crosslinking sites, uniformly dispersed within a continuous phase dominated by soft segments. These hard-phase aggregates exhibit reversible dynamic interactions (such as hydrogen bonding), acting as sacrificial bonds to enhance the material's toughness during deformation. Therefore, polyurea as a framework is expected to impart excellent mechanical strength and toughness to polymer gel electrolytes. However, highly polar liquid plasticizers or those containing hydrogen bond donors / acceptors are incompatible with polyurea networks, easily disrupting the microphase separation structure of the polyurea network. This results in existing polyurea-based polymer gel electrolytes failing to achieve the desired mechanical properties, leading to poor cycle performance in assembled lithium-ion batteries. Summary of the Invention

[0004] To address the aforementioned deficiencies or improvement needs of existing technologies, the present invention aims to provide a polyurea-based gel electrolyte, its preparation method, and its applications. By improving the specific composition and detailed structure of the electrolyte, polyetheramine (which may also be used in conjunction with polyethylene oxide) is used as the soft segment, and polyisocyanate containing a benzene ring structure is used as the hard segment. Under the induction of a eutectic solvent, the soft and hard segments can be separated. The polyetheramine (which may also be used in conjunction with polyethylene oxide) and the eutectic solvent act as functional phases to transport ions, while the benzene ring stacking structure formed through hydrogen bonding and π-π interactions serves as a reinforcing phase to maintain the mechanical stability of the electrolyte. The separation of the functional and reinforcing phases achieves a dual improvement in electrochemical and mechanical properties. Due to the presence of the phase-separated structure, the gel electrolyte of this invention possesses both excellent mechanical strength and electrochemical performance. Furthermore, the preparation method is simple, the conditions are mild, and it is suitable for large-scale production.

[0005] To achieve the above objectives, according to one aspect of the present invention, a polyurea-based gel electrolyte is provided, characterized in that the electrolyte comprises soft segments, hard segments, and a eutectic solvent component, wherein the soft segments are polyetheramines, the hard segments are polyisocyanates containing benzene ring structures, the soft segments and the hard segments are first formed into a polyurea skeleton, and the soft segments and hard segments can be separated under the induction of the eutectic solvent.

[0006] As a further preferred embodiment of the present invention, the soft segment further includes polyethylene oxide.

[0007] As a further preferred embodiment of the present invention, both the polyethylene oxide and the polyetheramine are aminopropyl-terminated; preferably, the molecular weight of the polyethylene oxide is 800 to 6000, more preferably including one or more of 800, 1000, 2000, 3000, 4000 and 4600; the molecular weight of the polyetheramine is 200 to 3000, more preferably including one or more of 230, 400, 1000, 2000 and 3000.

[0008] As a further preferred embodiment of the present invention, the polyisocyanate includes one or more of toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), and terephthalic diisocyanate (PDI).

[0009] The soft segment and the hard segment first form a polyurea skeleton, specifically under the action of a chain extender; the chain extender includes one or more of p-phenylenediamine, m-phenylenediamine, diphenylmethanediamine, 1,4-cyclohexanediamine, and hexamethylenediamine.

[0010] As a further preferred embodiment of the present invention, the raw materials for preparing the polyurea-based gel electrolyte simultaneously include polyetheramine, polyisocyanate and eutectic solvent, wherein the molar ratio of the polyetheramine to the polyisocyanate is 1:(2-3).

[0011] Preferably, the raw materials for preparing the polyurea-based gel electrolyte simultaneously include polyethylene oxide, polyetheramine, polyisocyanate, chain extender, and eutectic solvent, wherein,

[0012] The molar ratio of the polyethylene oxide to the polyetheramine is (0-4):1;

[0013] The total amount of the polyethylene oxide and the polyetheramine is in a molar ratio of 1:(2-3) to the polyisocyanate.

[0014] The molar ratio of the chain extender to the polyisocyanate is (0-2):1.

[0015] As a further preferred embodiment of the present invention, the eutectic solvent comprises both component A and component B, wherein component A is one or more of lithium bis(trifluoromethanesulfonyl)imide, lithium difluorooxalate borate, lithium bis(fluorosulfonyl)imide, and lithium hexafluorophosphate; and component B is one or more of succinate, ethylene carbonate, propylene carbonate, and dimethyl sulfoxide.

[0016] According to another aspect of the present invention, the present invention provides a method for preparing the above-mentioned polyurea-based gel electrolyte, characterized by comprising the following steps:

[0017] (1) Using polyetheramine as the soft segment raw material, the soft segment raw material and polyisocyanate are mixed in a solvent to carry out a polycondensation reaction to obtain isocyanate-terminated polyurea prepolymer.

[0018] (2) The polyurea prepolymer obtained in step (1) is subjected to a chain extension reaction to obtain a polyurea skeleton material;

[0019] (3) After dissolving the polyurea skeleton material obtained in step (2) in a mixed solvent of N,N-dimethylformamide and ethanol, a polyurea porous film is obtained by electrospinning.

[0020] Preferably, the electrospinning process parameters are as follows: negative voltage 2-4 kV, positive voltage 7-16 kV; solution flow rate 0.1-0.5 ml / min. -1 The distance between the needle tip and the receiver tube should be 10–20 cm; the receiver tube rotation speed should be 40–80 rpm. -1 The polymer concentration is 10–20 wt%.

[0021] (4) Adding a eutectic solvent to the polyurea porous film obtained in step (3) will yield a polyurea-based gel electrolyte.

[0022] As a further preferred embodiment of the present invention, the reaction temperature of the polycondensation reaction in step (1) and the chain extension reaction in step (2) are both 0 to 5°C, and the reaction time is controlled to be 12 to 24 h.

[0023] As a further preferred embodiment of the present invention, in step (1), the soft segment raw material further includes polyethylene oxide;

[0024] Both the polyethylene oxide and the polyetheramine are aminopropyl-terminated; preferably, the molecular weight of the polyethylene oxide includes one or more of 800, 1000, 2000 and 4600; and the molecular weight of the polyetheramine includes one or more of 230, 400, 1000 and 2000.

[0025] The polyisocyanate includes one or more of toluene diisocyanate, diphenylmethane diisocyanate, and terephthalic diisocyanate;

[0026] The molar ratio of the polyethylene oxide to the polyetheramine is (1-4):1;

[0027] The total amount of the polyethylene oxide and the polyetheramine is in a molar ratio of 1:(2-3) to the polyisocyanate.

[0028] In step (2), the chain extension reaction specifically involves mixing the polyurea prepolymer with a chain extender in a solvent to carry out the chain extension reaction; the chain extender includes one or more of p-phenylenediamine, m-phenylenediamine, diphenylmethanediamine, 1,4-cyclohexanediamine, and hexamethylenediamine; the molar ratio of the chain extender to the remaining polyisocyanate in the system after the reaction in step (1) is 1:1;

[0029] The solvent in step (1) and the solvent in step (2) are both N,N-dimethylformamide;

[0030] In step (3), the mixed solvent of N,N-dimethylformamide and ethanol is specifically a mixed solvent obtained by N,N-dimethylformamide and ethanol in a volume ratio of 4:1.

[0031] According to another aspect of the present invention, the present invention provides the application of the above-mentioned polyurea-based gel electrolyte in the field of energy storage and ion skin;

[0032] Preferably, the application in the field of energy storage is specifically applied to lithium-ion batteries or lithium metal batteries.

[0033] Compared with existing technologies, the gel electrolytes prepared by existing technologies are difficult to use in lithium batteries due to poor mechanical strength. Commonly used reinforcement methods (such as covalent crosslinking) have poor processability and are difficult to recycle. Furthermore, the high crosslinking density restricts chain segment movement and weakens ion transport performance. In contrast, this invention designs the framework structure of the gel electrolyte, using specific types of soft and hard segment components. Polyetheramine (which may also be used in conjunction with polyethylene oxide) is used as the soft segment, and polyisocyanates containing benzene ring structures are used as the hard segment. Under the induction of a eutectic solvent, phase separation can be achieved, resulting in a polyurea-based gel electrolyte with a phase-separated structure and excellent mechanical and electrochemical properties. Moreover, the cyano group is a strong electron-withdrawing group, exhibiting a low minimum unoccupied orbital and excellent electrochemical stability. Many cyano compounds are common components of lithium-ion battery electrolytes, such as acetonitrile, succinate, and polyacrylonitrile. Taking succinate as an example, succinate has a single plastic crystalline phase between -35℃ and 62℃. This unique plastic crystalline phase causes the succinate molecule to exhibit trans-levorotatory isomerism, that is, the cyano group rotates around the central C-C bond. Therefore, the eutectic solvent composed of succinate and lithium salt can achieve a viscosity of 10 at room temperature. -3 S cm -1 The ultra-high ionic conductivity. Similar to ethylene carbonate, propylene carbonate, and dimethyl sulfoxide, they also contain ester groups that can coordinate with lithium ions, and the resulting eutectic solvent plays a significant role. The aforementioned properties of eutectic solvents are known in the prior art and can impart electrochemical properties to polymers. However, a disadvantage is that the strength of the material is greatly reduced after doping with the eutectic solvent (most reported in the literature are below 1 MPa). This invention, by improving the composition and structure of the polymer, yields a gel electrolyte after doping with the eutectic solvent. Compared with other gel electrolytes in the prior art, the gel electrolyte exhibits superior mechanical strength.

[0034] This invention also optimizes the dosage of various raw materials used in the preparation of polyurea-based gel electrolytes by using specific amounts of polyetheramine (polyethylene oxide can also be used in addition) and isocyanate, and can introduce chain extenders with different structures to regulate the assembly structure of the gel electrolyte. The large polarity difference between the soft segments dominated by aliphatic chains and the hard segments dominated by benzene rings results in a separated structure that endows this type of material with excellent mechanical strength. The hard segments are dynamically cross-linked by π-π and hydrogen bonds; during deformation, these dynamic interactions continuously open and rebuild, dissipating energy and giving this type of material excellent mechanical toughness. When a eutectic solvent is loaded onto the polyurea backbone, due to its different compatibility with polyethylene oxide, polyetheramine, and benzene rings, a phase-separated structure is formed, with polyether polyol (polyethylene oxide and polyetheramine) / eutectic solvent as the continuous phase and benzene ring aggregates as the dispersed phase. The dispersed phase acts as physical cross-linking sites, enhancing the mechanical properties of the gel electrolyte, while the continuous phase promotes lithium-ion conduction and optimizes battery performance.

[0035] In specific analysis, the present invention can achieve the following beneficial effects:

[0036] 1. The polyurea-based gel electrolyte provided by this invention uses polyetheramine (and optionally polyethylene oxide) as the soft segment and polyisocyanate containing a benzene ring structure as the hard segment. Under the induction of a eutectic solvent, the soft and hard segments can achieve phase separation, giving the polyurea-based gel electrolyte excellent mechanical properties. Under the action of the eutectic solvent (DES), the polyether polyol and the benzene ring will undergo phase separation (a schematic diagram of the microstructural transformation of phase separation is shown below). Figure 9 As shown in the diagram, the eutectic solvent is dispersed in the polyether polyol as the continuous phase, while the hard segments containing benzene rings aggregate together to form the dispersed phase. The dispersed phase contains both π-π and hydrogen bonds, which act as physical crosslinking sites and enhance the mechanical strength of the gel electrolyte.

[0037] 2. The excellent mechanical properties of polyurea stem from the high-density hydrogen bond crosslinking within the material. Based on this invention, the molar ratio of polyetheramine (or the total amount of polyetheramine and polyoxyethylene if additional polyethylene oxide is used) to polyisocyanate can be controlled at 1:(2-3). A chain extender can be preferably used, and the molar ratio of the chain extender to polyisocyanate can be controlled at (1-2):1. Therefore, the restricted chain segment movement cannot assist ion transport within the polymer network. After loading with a eutectic solvent, dynamic interactions (π-π and hydrogen bond interactions) are confined to the dispersed phase, while the eutectic solvent acts as a plasticizer, activating chain segment movement. Both aspects jointly promote the improvement of ionic conductivity.

[0038] 3. During charging and discharging, lithium batteries rely on the continuous extraction and insertion of lithium ions at the positive and negative electrodes. Therefore, restricting the movement of anions can increase the lithium-ion transference number, thereby enhancing interface stability and optimizing cycle performance. The presence of a large number of highly polar urea groups in polyurea can adsorb anions, while the cyano groups in succinate can also inhibit anion movement. Both factors work together to promote the increase of the lithium-ion transference number.

[0039] 4. Traditional gel electrolytes incorporate covalent cross-linking structures to enhance their mechanical strength; however, the cross-linked polymers cannot be reprocessed or recycled, which is particularly detrimental to the future reuse of solid-state electrolytes. The gel electrolyte obtained in this invention achieves the separation of soft and hard segments under the induction of a eutectic solvent. The hard segment aggregation domains serve as physical cross-linking sites, optimizing material strength while endowing it with self-healing capabilities, extending the electrolyte's lifespan and improving battery safety during operation. Furthermore, thanks to the characteristics of physical cross-linking, the prepared gel electrolyte can be further processed through dissolution and casting.

[0040] Battery safety is paramount compared to electrochemical performance. Imparting self-healing capabilities to gel electrolytes can extend battery life and improve safety by spontaneously repairing minute internal damage. The gel electrolyte provided in this invention possesses excellent self-healing capabilities, driven primarily by enhanced chain segment movement after plasticization and highly dynamic π-π and hydrogen bond interactions. Lithium-ion batteries rely on the continuous extraction and insertion of lithium ions at the positive and negative electrodes during charging and discharging. Therefore, restricting anion mobility can increase the lithium-ion transference number, thereby improving interfacial stability and optimizing cycle performance. The presence of numerous strongly polar urea groups in polyurea can adsorb anions, while the cyano groups in succinate can inhibit anion movement, both contributing to an increase in the lithium-ion transference number. Traditional gel electrolytes introduce covalent cross-linking structures to enhance mechanical strength; however, cross-linked polymers cannot be reprocessed or recycled, which is crucial for the future reuse of solid-state electrolytes. The gel electrolyte prepared in this patent achieves separation of soft and hard segments under eutectic solvent induction. The hard segment aggregation domains serve as physical cross-linking sites, optimizing material strength while endowing it with self-healing capabilities, extending electrolyte life and improving battery safety during operation.

[0041] 5. Furthermore, the energy density of lithium batteries is one of the important parameters for commercial applications. This invention particularly favors the use of electrospinning technology to prepare the skeletal separator, then adding a eutectic solvent dropwise onto the porous separator, followed by heating and settling to obtain a gel electrolyte. This method can reduce the separator thickness and increase the energy density, while also optimizing the battery assembly process and avoiding the evaporation of the eutectic solvent during casting.

[0042] 6. In addition, the synthesis of polyurea materials does not require harsh environments or complex operating steps. It can be prepared in a one-pot process, which is simple and suitable for large-scale production.

[0043] In summary, the polyurea-based gel electrolyte of this invention possesses excellent mechanical and electrochemical properties, and its preparation method is simple and suitable for large-scale production. This gel electrolyte, reinforced by physical cross-linking, exhibits self-healing capabilities, restoring its mechanical and electrochemical properties, thereby effectively improving the safety and durability of the electrolyte during use and extending the lifespan of equipment. This material has significant application value in the field of energy storage. Attached Figure Description

[0044] Figure 1 The infrared spectrum of the polyurea film prepared in Example 1 is shown.

[0045] Figure 2 The images show the physical specimens of the polyurea skeleton prepared in Example 1, including casting, electrospinning, and the final gel electrolyte film; wherein, Figure 2 a) in the text corresponds to casting. Figure 2b) in the text corresponds to electrospinning. Figure 2 c) corresponds to the gel electrolyte film obtained after doping with the eutectic solvent.

[0046] Figure 3 This is a schematic diagram of the stress-strain curves of the polyurea film and polyurea-based gel electrolyte prepared in Example 1; wherein, Figure 3 a) in the text corresponds to polyurea film. Figure 3 b) in the text corresponds to polyurea-based gel electrolyte.

[0047] Figure 4 The graph shows the ionic conductivity-temperature curve, electrochemical window test results, and lithium-ion transference number test results of the gel electrolyte prepared in Example 1; among them, Figure 4 a) in the figure corresponds to the ionic conductivity-temperature curve. Figure 4 Figure b) corresponds to the electrochemical window test results. Figure 4 c) in the figure corresponds to the lithium-ion transference number test results (the inset is the interface impedance diagram before and after polarization. Before polarization corresponds to the initial state, and the legend in the figure is a black square; after polarization corresponds to the stable state, and the legend in the figure is a gray square).

[0048] Figure 5 The charge-discharge cycle curves are shown for a button cell assembled using the gel electrolyte prepared in Example 2 as the separator material.

[0049] Figure 6 These are atomic force microscopy images of the polyurea framework prepared in Example 3 before and after solvent doping with the eutectic solvent; wherein, Figure 6 a) corresponds to the doped eutectic solvent before, Figure 6 b) corresponds to the doping of the eutectic solvent.

[0050] Figure 7 This is a schematic diagram of the stress-strain curves of the polyurea film and polyurea-based gel electrolyte prepared in Example 4; wherein, Figure 7 a) in the text corresponds to polyurea film. Figure 7 b) in the text corresponds to polyurea-based gel electrolyte.

[0051] Figure 8 The images show the stress-strain curves of the polyurea film prepared in Comparative Example 1 and a photograph of the gel electrolyte after doping with the eutectic solvent; among them, Figure 8 a) in the figure corresponds to the strain curve of the polyurea film. Figure 8 b) in the diagram corresponds to the physical image of the gel electrolyte.

[0052] Figure 9 This is a schematic diagram of the microstructure transformation of polyether polyol and benzene ring phase separation in this invention. Detailed Implementation

[0053] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0054] In summary, the polyurea-based gel electrolyte of this invention can be prepared through the following steps:

[0055] (1) Polyetheramine (polyethylene oxide can also be used in addition), polyisocyanate and solvent (e.g. N,N-dimethylformamide) are mixed and subjected to polycondensation reaction to obtain isocyanate-terminated polyurea prepolymer;

[0056] (2) The polyurea prepolymer obtained in step (1) is mixed with a solvent (e.g., N,N-dimethylformamide) and subjected to a chain extension reaction to obtain a polyurea backbone material; a chain extender may be used in this step.

[0057] (3) The polyurea skeleton material obtained in step (2) is dissolved in a mixed solvent of N,N-dimethylformamide and ethanol (volume ratio can be 4:1), and then electrospinned to obtain a polyurea porous film.

[0058] (4) Assemble the polyurea porous film obtained in step (3) into a battery. During the battery assembly process, add a eutectic solvent to the polyurea porous film and heat and let it stand to obtain a polyurea-based gel electrolyte.

[0059] Specifically, it is possible to: (1) obtain a prepolymer by stepwise polymerization of polyetheramines of different molecular weights (polyethylene oxide can also be used in addition, that is, polyethylene oxide is optional) with polyisocyanates containing benzene ring structures, and add small molecule chain extenders to enhance the mechanical strength of the electrolyte material and optimize the phase separation structure; (2) prepare a porous film skeleton using electrospinning technology, and obtain a polyurea-based gel electrolyte with functional phase and reinforcing phase separation by swelling in a eutectic solvent. The mechanical properties, electrochemical properties, interfacial stability and self-healing ability of this gel electrolyte can all be improved.

[0060] The polyethylene oxide and polyetheramine are aminopropyl-terminated. The preferred reaction sequence with isocyanate is as follows: polyethylene oxide, polyetheramine, and solvent are mixed to obtain a prepolymer solution; isocyanate and solvent are mixed to obtain an isocyanate solution; and the isocyanate solution is then added dropwise to the polyethylene oxide and polyetheramine solution. Furthermore, the isocyanate solution should be added dropwise to the polymer solution under ice bath conditions. The preferred dropping rate of the isocyanate solution is 1–2 drops / second. By adopting this preferred mixing sequence, it is possible to avoid the isocyanate reacting too quickly with the amino groups in the polyethylene oxide and polyetheramine to form a gel or undergo explosive polymerization; it also allows for the sufficient removal of heat released from the reaction between isocyanate and amino groups, preventing overheating and oxidation, which could negatively impact the material's mechanical properties, electrochemical properties, interfacial stability, and self-healing capabilities.

[0061] The following are specific examples:

[0062] Example 1

[0063] Aminopropyl-terminated polyetheramine (4 mmol) was dissolved in ultra-dry N,N-dimethylformamide (DMF) to obtain a polyetheramine solution; terephthalic diisocyanate (PPDI, 8 mmol) was dissolved in a small amount of ultra-dry DMF to obtain an isocyanate solution; then, the isocyanate solution was added to the polyetheramine solution, and the mixture was reacted in an ice bath for 1 h, followed by a reaction at room temperature for 24 h to obtain the isocyanate-terminated intermediate product, polyurea prepolymer.

[0064] p-phenylenediamine (4 mmol) was dissolved in a small amount of ultra-dry DMF. The resulting p-phenylenediamine solution was added dropwise to the polyurea prepolymer and the reaction was continued for 24 h. The resulting polymer solution was poured into a polytetrafluoroethylene mold. After the solvent evaporated, a polyurea film was obtained. The thickness of the film was controlled to be 0.4–0.8 mm for tensile testing.

[0065] A suitable amount of polyurea film was dissolved in a mixed solvent of N,N-dimethylformamide and ethanol (volume ratio 4:1), and a porous film with a thickness of 30-80 μm was obtained by electrospinning, which is referred to as porous polyurea film.

[0066] Succinate and LiTFSI were mixed at a molar ratio of 4:1 to obtain a eutectic solvent, and then 1-5 mol% LiDFOB was added as an interface stabilizing additive.

[0067] The chemical structure of the cast polyurea film was verified using Fourier transform infrared spectroscopy, and the results are as follows: Figure 1 As shown. The wave number is 3343 cm⁻¹. -1 It is the stretching vibration peak of NH; wavenumber range 2990–2840 cm⁻¹ -1 The peaks represent the stretching vibrations of -CH3 and -CH2-; wavenumber 1693 cm⁻¹. -1 and 1651cm-1 The peaks represent the stretching vibrations of C=O in two different chemical environments. Infrared results indicate that the desired polyurea film was successfully synthesized.

[0068] The difference in polarity between hard and soft segments leads to phase separation structures within the material, whose size is smaller than the wavelength of visible light. Therefore, materials cast from solutions exhibit a colorless and transparent appearance (e.g., [image of a specific material]). Figure 2 As shown in a)). Electrospinning is a special form of electrostatic atomization of polymer fluids. In this case, the atomized material is not a tiny droplet, but a polymer microjet that can travel a considerable distance and eventually solidify into fibers. The porous film formed by overlapping polymer fibers is white and opaque (as shown in a)). Figure 2 As shown in b), this is because electrospinning is a rapid film-forming process. During electrospinning, the polymer chains do not have enough time to align and form a separated structure, or it can be understood that the formed separated structure has defects, thus leading to this opaque state. Under the induction of a eutectic solvent, the film obtained by electrospinning changes from completely opaque to translucent (e.g., ...). Figure 2 (As shown in c). The change in physical state indicates that the eutectic solvent is not physically adsorbed in the porous structure, but rather permeates into the polymer network, inducing further separation of the soft and hard segments. Its size is larger than the visible light wavelength, and the material becomes translucent.

[0069] Mechanical properties of cast polyurea films were tested using the following method: the polyurea film was cut into standard shapes and tested using a universal testing machine. The results are as follows. Figure 3 As shown. From Figure 3 As can be seen from a), the polyurea film prepared by the present invention has a mechanical strength of 42.3 MPa and an elongation at break of 980%, which shows that the polyurea elastomer has excellent mechanical properties. Figure 3 b) shows the tensile curve of the polymer gel electrolyte film. Due to the plasticizing effect of the eutectic solvent, its strength drops to 3.1 MPa, while its elongation at break decreases to 520%. The porous film obtained by spinning, after adding DES, undergoes swelling and induced polymer chain rearrangement, becoming a non-porous bulk material similar to the cast film.

[0070] The electrochemical performance of the gel electrolyte was then characterized using the following methods: Several circular samples with a diameter of 18 mm were cut from the polyurea-based gel electrolyte material film. The ionic conductivity of the electrolyte was tested by assembling a button cell with the following structure: negative electrode shell, gasket, electrolyte, gasket, spring, positive electrode shell. The lithium-ion transference number of the electrolyte was tested by assembling a button cell with the following structure: negative electrode shell, gasket, lithium plate, electrolyte, lithium plate, gasket, positive electrode shell. The electrochemical stability of the electrolyte was tested by assembling a button cell with the following structure: negative electrode shell, gasket, lithium plate, electrolyte, gasket, spring, positive electrode shell.

[0071] The relationship between the ionic conductivity of the polyurea-based gel electrolyte and temperature is as follows: Figure 4 As shown in a), its room temperature lithium-ion conductivity reaches 9.8 × 10⁻⁶. -5 S cm -1 The ionic conductivity at 60℃ is 3.1 × 10⁻⁶. -4 S cm -1 This indicates that the eutectic solvent can promote the separation of hard and soft segments and the movement of soft segments, thereby improving ionic conductivity. The electrochemical stability window of this electrolyte is tested as follows: Figure 4 As shown in b), its oxidation potential is 4.77 V, which is higher than that of the liquid electrolyte (4.2–4.3 V). This demonstrates that the stable chemical structure of polyurea materials can improve the electrochemical stability of solid electrolytes. The lithium-ion transference number test results for this electrolyte are shown in [Figure 1]. Figure 4 As shown in c), since there are a large number of urea groups inside the polyurea material, which can inhibit the movement of anions, its lithium-ion transference number is higher than 0.5, which greatly improves the stability of the battery during cycling.

[0072] Half-cells were assembled using polyurea-based gel electrolyte and charge-discharge tests were conducted. The results showed that the electrolyte had excellent cycle stability, with a capacity retention of over 90% after 100 cycles at 60℃ and 0.5C.

[0073] Example 2

[0074] 50 g of aminopropyl-terminated polyetheramine and 100 g of aminopropyl-terminated polyethylene glycol were dissolved in ultra-dry N,N-dimethylformamide (DMF) to obtain a mixed solution, which is a polymer solution. 56 g of diphenylmethane diisocyanate (MDI) was dissolved in an appropriate amount of ultra-dry DMF to obtain an isocyanate solution. The isocyanate solution was added to the polymer solution, and the mixture was reacted in an ice bath for 1 h, followed by reaction at room temperature for 24 h to obtain a polyurea solution. The obtained polyurea solution was poured into a polytetrafluoroethylene mold, and after solvent evaporation, a polyurea film was obtained. The thickness of the film was controlled to be 0.4–0.8 mm to facilitate tensile testing.

[0075] Dissolve an appropriate amount of polyurea in a mixed solvent of N,N-dimethylformamide and ethanol (volume ratio 4:1), and obtain a porous polyurea film with a thickness of 30-80 μm by electrospinning.

[0076] Succinate and LiTFSI were mixed at a molar ratio of 5:1 to obtain a eutectic solvent, and then 1-5 mol% of LiDFOB was added as an interface stabilizing additive.

[0077] The chemical structure of the cast polyurea film was verified using nuclear magnetic resonance spectroscopy. Chemical shifts of 5.95 and 8.41 ppm were attributed to two types of hydrogen atoms in the urea group, one linked to the aliphatic chain and the other to the benzene ring. Chemical shifts of 7.1 and 7.4 ppm represented hydrogen atoms on the benzene ring backbone. The NMR results confirm the successful preparation of the polyurea in this embodiment.

[0078] Mechanical properties of the cast polyurea film were tested using the following method: the polyurea film was cut into a standard shape and tested using a universal testing machine. The polyurea film prepared in this embodiment exhibited a mechanical strength of 27.8 MPa and an elongation at break of 1390%, demonstrating the excellent mechanical properties of this polyurea elastomer. After loading with a eutectic solvent, the strength of the polyurea gel electrolyte decreased to 1.4 MPa, and the elongation at break decreased to 710%. This is due to the reduced proportion of unextended polyurea hard segments.

[0079] The electrochemical performance of the material was then characterized using the following methods: Several circular samples with a diameter of 18 mm were cut from the polyurea-based gel electrolyte material film. The ionic conductivity of the electrolyte was tested by assembling a button cell with the following structure: negative electrode shell, gasket, electrolyte, gasket, spring, positive electrode shell. The lithium-ion transference number of the electrolyte was tested by assembling a button cell with the following structure: negative electrode shell, gasket, lithium sheet, electrolyte, lithium sheet, gasket, positive electrode shell. The electrochemical stability of the electrolyte was tested by assembling a button cell with the following structure: negative electrode shell, gasket, lithium sheet, electrolyte, gasket, spring, positive electrode shell.

[0080] The relationship between the ionic conductivity of this electrolyte and temperature was verified, and its room temperature lithium-ion conductivity was 1.1 × 10⁻⁶. - 4 S cm -1 The ionic conductivity at 60℃ is 2.3 × 10⁻⁶. -3 S cm -1 The increased ionic conductivity is due to the combined effect of the eutectic solvent promoting chain segment movement and the reduction in the proportion of hard segments. The gel electrolyte material prepared in this embodiment has an electrochemical window of 4.81 V and a lithium-ion transference number of 0.53.

[0081] The charge and discharge results of the half-cell assembled using this electrolyte are as follows: Figure 5 As shown, the electrolyte exhibits excellent cycling stability, with a capacity retention rate exceeding 90% after 100 cycles at 60°C and 1C.

[0082] Example 3

[0083] A mixture of aminopropyl-terminated polyetheramine (20g) and aminopropyl-terminated polyethylene glycol (20g) was dissolved in ultra-dry N,N-dimethylformamide (DMF) to form a polymer solution. Toluene diisocyanate (TDI, 12g) was dissolved in an appropriate amount of ultra-dry DMF to obtain an isocyanate solution. The above isocyanate solution was added to the polymer solution, and the mixture was reacted in an ice bath for 1 hour, followed by a reaction at room temperature for 24 hours to obtain the isocyanate-terminated intermediate product, polyurea prepolymer.

[0084] Diphenylmethane diamine (7g) was dissolved in an appropriate amount of ultra-dry DMF solvent. The resulting diphenylmethane diamine solution was added dropwise to the polyurea prepolymer system, and the reaction was continued for 24 hours. The resulting polymer solution was poured into a polytetrafluoroethylene mold, and after the solvent evaporated, a polyurea film was obtained. The thickness of the film was controlled to be 0.4–0.8 mm to facilitate tensile testing.

[0085] Dissolve an appropriate amount of polyurea in a mixed solvent of N,N-dimethylformamide and ethanol (volume ratio 4:1), and obtain a porous polyurea film with a thickness of 30-80 μm by electrospinning.

[0086] Succinate and LiTFSI were mixed at a molar ratio of 4:1 to obtain a eutectic solvent, and then 1-5 mol% LiDFOB was added as an interface stabilizing additive.

[0087] The successful preparation of polyurea was verified by Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy. The results were similar to those in Example 1 and will not be repeated here.

[0088] The mechanical properties of the polyurea film were tested using the following method: the polyurea film was cut into a standard shape and tested using a universal testing machine. The polyurea film prepared in this embodiment exhibited a mechanical strength of 52.6 MPa and an elongation at break of 920%, demonstrating the excellent mechanical properties of this polyurea elastomer. After loading with a eutectic solvent, the strength of the polyurea gel electrolyte decreased to 3.9 MPa, and the elongation at break decreased to 620%.

[0089] The phase separation structure of the polyurea backbone and the corresponding gel electrolyte was observed using atomic force microscopy, and the results are as follows: Figure 6 As shown. Before doping with the eutectic solvent, the hard segments (bright areas) are the continuous phase, while the soft segments (dark areas) are the dispersed phase (e.g., ...). Figure 6 (as shown in a)). This is because polyurea contains a large number of hard segment aggregates, with soft segments hidden within them. The result is exactly the opposite after loading a eutectic solvent: the soft segments become the continuous phase while the hard segments become the dispersed phase. This is due to the different compatibility between the eutectic solvent and the soft and hard segments. Figure 6 (as shown in b)). The presence of the eutectic solvent can induce the separation of soft and hard segments, in which the hard segments are distributed as physical cross-linking sites in a continuous phase dominated by soft segments and the eutectic solvent. The rational structure enables the gel electrolyte to have both excellent mechanical and electrochemical properties.

[0090] The electrochemical performance of the material was then characterized using the following methods: Several circular samples with a diameter of 18 mm were cut from the polyurea-based gel electrolyte material film. The ionic conductivity of the electrolyte was tested by assembling a button cell with the following structure: negative electrode shell, gasket, electrolyte, gasket, spring, positive electrode shell. The lithium-ion transference number of the electrolyte was tested by assembling a button cell with the following structure: negative electrode shell, gasket, lithium sheet, electrolyte, lithium sheet, gasket, positive electrode shell. The electrochemical stability of the electrolyte was tested by assembling a button cell with the following structure: negative electrode shell, gasket, lithium sheet, electrolyte, gasket, spring, positive electrode shell.

[0091] The relationship between the ionic conductivity of this electrolyte and temperature was verified, and its room temperature lithium-ion conductivity was 6.7 × 10⁻⁶. - 5 S cm -1 The ionic conductivity at 60℃ is 1.8 × 10⁻⁶. -4 S cm -1 The eutectic solvent promotes chain segment movement, thereby increasing ionic conductivity. The gel electrolyte material prepared in this embodiment has an electrochemical window of 5.01 V and a lithium-ion transference number of 0.63.

[0092] The electrolyte was used to assemble half-cells for charge-discharge tests. The results showed that the electrolyte had excellent cycle stability. After 100 cycles at 60℃ and 1C, the capacity retention rate was higher than 90%.

[0093] Example 4

[0094] Aminaminopropyl-terminated polyetheramine (4 mmol) and aminopropyl-terminated ethylene oxide (2 mmol) were dissolved in ultra-dry N,N-dimethylformamide (DMF) to obtain a polymer solution; terephthalic diisocyanate (8 mmol) and toluene diisocyanate (10 mmol) were dissolved in a small amount of ultra-dry DMF to obtain an isocyanate solution; then, the isocyanate solution was added to the polymer solution, reacted in an ice bath for 1 h, and then reacted at room temperature for 24 h to obtain the isocyanate-terminated intermediate product, polyurea prepolymer.

[0095] 5 mmol of p-phenylenediamine and 5 mmol of hexamethylenediamine were dissolved in a small amount of ultra-dry DMF. The resulting p-phenylenediamine and hexamethylenediamine solution was added dropwise to the polyurea prepolymer and the reaction was continued for 24 h. The resulting solution was poured into a polytetrafluoroethylene mold and the solvent was evaporated to obtain a polyurea film. The thickness of the film was controlled to be 0.4–0.8 mm for tensile testing.

[0096] A suitable amount of polyurea film was dissolved in a mixed solvent of N,N-dimethylformamide and ethanol (volume ratio 4:1), and a porous film with a thickness of 30-80 μm was obtained by electrospinning, which is referred to as porous polyurea film.

[0097] Ethylene carbonate and lithium difluorosulfonyl imide were mixed at a molar ratio of 5:1 to obtain a eutectic solvent, and then 1-5 mol% of LiDFOB was added as an interface stabilizing additive.

[0098] The chemical structure of the polyurea film was verified using Fourier transform infrared spectroscopy. The wavenumber was 3342 cm⁻¹. -1 It is the stretching vibration peak of NH; wavenumber range 2990–2840 cm⁻¹ -1 The peaks represent the stretching vibrations of -CH3 and -CH2-; wavenumbers 1702, 1692, 1683, and 1652 cm⁻¹. -1 The peaks represent the stretching vibrations of C=O in four different chemical environments. Infrared results indicate that the desired polyurea film was successfully synthesized.

[0099] The mechanical properties of the polyurea film were tested using the following method: the polyurea film was cut into standard shapes and tested using a universal testing machine. The results are as follows. Figure 7 As shown. From Figure 7 As can be seen from a), the polyurea film prepared by the present invention has a yield strength of 38.1 MPa and an elongation at break of 390%, which shows that the polyurea elastomer has excellent mechanical properties. Figure 7 b) is the tensile curve of the polymer gel electrolyte film. Due to the plasticizing effect of the eutectic solvent, its strength drops to 7.1 MPa, while the elongation at break is 495%.

[0100] The electrochemical performance of the gel electrolyte was then characterized using the following methods: Several circular samples with a diameter of 18 mm were cut from the polyurea-based gel electrolyte material film. The ionic conductivity of the electrolyte was tested by assembling a button cell with the following structure: negative electrode shell, gasket, electrolyte, gasket, spring, positive electrode shell. The lithium-ion transference number of the electrolyte was tested by assembling a button cell with the following structure: negative electrode shell, gasket, lithium plate, electrolyte, lithium plate, gasket, positive electrode shell. The electrochemical stability of the electrolyte was tested by assembling a button cell with the following structure: negative electrode shell, gasket, lithium plate, electrolyte, gasket, spring, positive electrode shell.

[0101] The polyurea-based gel electrolyte achieved a room-temperature lithium-ion conductivity of 5.4 × 10⁻⁶. -5 S cm -1 The ionic conductivity at 60℃ is 1.2 × 10⁻⁶. -4 S cm -1This indicates that the eutectic solvent can promote the separation of hard and soft segments and the movement of soft segments, thereby improving ionic conductivity. The electrochemical stability window of this electrolyte is 5.1V, which is higher than that of liquid electrolytes (4.2–4.3V). This demonstrates that the stable chemical structure of polyurea materials can improve the electrochemical stability of solid-state electrolytes. Because the polyurea material contains a large number of urea groups that can inhibit anion movement, its lithium-ion transference number is higher than 0.5, greatly improving the stability of the battery during cycling.

[0102] Half-cells were assembled using polyurea-based gel electrolyte and charge-discharge tests were conducted. The results showed that the electrolyte had excellent cycle stability, with a capacity retention of over 95% after 100 cycles at 60℃ and 0.2C.

[0103] Comparative Example 1

[0104] 20 g of aminopropyl-terminated polyetheramine was dissolved in ultra-dry N,N-dimethylformamide (DMF) and stirred at room temperature for 10 min to obtain a polyetheramine solution. 6.7 g of hexamethylene diisocyanate (HDI; without benzene ring) was dissolved in ultra-dry DMF to obtain an isocyanate solution. The above isocyanate solution was added to the polyetheramine solution, and the mixture was reacted in an ice bath for 1 h, followed by reaction at room temperature for 24 h to obtain the isocyanate-terminated intermediate product, a polyurea prepolymer.

[0105] 1,6-Hexanediamine (2.3g) was dissolved in ultra-dry DMF, and the resulting solution was added dropwise to the polyurea prepolymer system. The reaction continued for 24 hours. The resulting polymer solution was poured into a polytetrafluoroethylene mold, and after the solvent evaporated, a polyurea film was obtained. The thickness of the film was controlled to be 0.4-0.8 mm to facilitate tensile testing.

[0106] Dissolve an appropriate amount of polyurea in a mixed solvent of N,N-dimethylformamide and ethanol (volume ratio 4:1), and obtain a porous polyurea film with a thickness of 30-80 μm by electrospinning.

[0107] Succinate and LiTFSI were mixed at a molar ratio of 4:1 to obtain a eutectic solvent, and then 1-5 mol% LiDFOB was added as an interface stabilizing additive.

[0108] The chemical structure of the cast polyurea film was verified using Fourier transform infrared spectroscopy. The wavenumber was 3340 cm⁻¹. -1 It is the stretching vibration peak of NH; wavenumber range 2990–2840 cm⁻¹ -1 The peaks represent the stretching vibrations of -CH3 and -CH2-; wavenumber 1693 cm⁻¹. -1 The peak is a stretching vibration of C=O; wavenumber 1531 cm⁻¹ -1 The peak represents the shear vibration of NH. Infrared results indicate that the polyurea framework material designed in this comparative example was successfully synthesized.

[0109] The mechanical properties of the polyurea film were tested using the following method: the polyurea film was cut into a standard shape and tested using a universal testing machine. Due to the lack of π-π interactions and the poor packing properties of the aliphatic hard segments, the material's strength decreased, while the elongation at break increased. The polyurea film prepared in this embodiment had a mechanical strength of 26.2 MPa and an elongation at break of 1460% (e.g., ...). Figure 8 As shown in a)). Meanwhile, the eutectic solvent has excellent compatibility with the aliphatic hard segments; therefore, the polyurea framework material prepared in this comparative example experiences a sharp decrease in strength and cannot self-support after loading with the eutectic solvent (as shown in a)). Figure 8 (as shown in b)).

[0110] The electrochemical performance of the material was then characterized using the following methods: A polymer gel electrolyte was loaded onto a cellulose membrane with a diameter of 18 mm. The ionic conductivity of the electrolyte was tested by assembling a coin cell with the following structure: negative electrode shell, spacer, electrolyte, spacer, spring, positive electrode shell. The lithium-ion transference number of the electrolyte was tested by assembling a coin cell with the following structure: negative electrode shell, spacer, lithium plate, electrolyte, lithium plate, spacer, positive electrode shell. The electrochemical stability of the electrolyte was tested by assembling a coin cell with the following structure: negative electrode shell, spacer, lithium plate, electrolyte, spacer, spring, positive electrode shell.

[0111] The relationship between the ionic conductivity of this electrolyte and temperature was verified, and its room temperature lithium-ion conductivity was 1.0 × 10⁻⁶. - 4 S cm -1 The ionic conductivity at 60℃ is 1.3 × 10⁻⁶. -3 S cm -1 Because the eutectic solvent provides a fluid-like material, the chain segment mobility is significantly enhanced, resulting in a marked improvement in conductivity. The gel electrolyte material prepared in this embodiment has an electrochemical window of 4.5V and a lithium-ion transference number of 0.41.

[0112] Half-cells assembled using this electrolyte were subjected to charge-discharge tests. The results showed that although the electrolyte had higher ionic conductivity, its mechanical properties dropped sharply to the point of being unsustainable due to the inability to form a phase-separated structure, resulting in poor cycle stability. After 50 cycles at 60°C and 0.2C, the capacity retention was only 61%.

[0113] All raw materials used in the above embodiments were commercially available. Furthermore, the above embodiments are merely examples; for instance, in addition to N,N-dimethylformamide (DMF), other solvents capable of dissolving polyethylene oxide, polyetheramine, and isocyanate, such as tetrahydrofuran (THF) and N,N-dimethylacetamide (DMAc), can also be used. The amount of solvent is not particularly limited, as long as it ensures the dissolution of the polyethylene oxide, polyetheramine, and isocyanate. For example, the ratio of total feed mass to solvent can be 50–100 mg: 1–2 ml. The method for treating the ultra-dry solvent can be found in existing technologies for drying.

[0114] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A polyurea-based gel electrolyte, characterized in that, The electrolyte comprises a soft segment, a hard segment, and a eutectic solvent. The soft segment is a polyetheramine, and the hard segment is a polyisocyanate containing a benzene ring structure. The soft segment and the hard segment first form a polyurea skeleton and can be separated from each other under the induction of the eutectic solvent. The eutectic solvent includes both component A and component B. Component A is one or more of lithium bis(trifluoromethanesulfonyl)imide, lithium difluorooxalate borate, lithium bis(fluorosulfonyl)imide, and lithium hexafluorophosphate. Component B is one or more of succinate, ethylene carbonate, propylene carbonate, and dimethyl sulfoxide.

2. The polyurea-based gel electrolyte as described in claim 1, characterized in that, The soft segment also includes polyethylene oxide.

3. The polyurea-based gel electrolyte as described in claim 2, characterized in that, Both the polyethylene oxide and the polyetheramine are aminopropyl-terminated.

4. The polyurea-based gel electrolyte as described in claim 3, characterized in that, The molecular weight of the polyethylene oxide is 800-6000; the molecular weight of the polyetheramine is 200-3000.

5. The polyurea-based gel electrolyte as described in claim 4, characterized in that, The molecular weight of the polyethylene oxide is one or more of 800, 1000, 2000, 3000, 4000 and 4600; the molecular weight of the polyetheramine is one or more of 230, 400, 1000, 2000 and 3000.

6. The polyurea-based gel electrolyte as described in claim 1, characterized in that, The polyisocyanate includes one or more of toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), and terephthalic diisocyanate; The soft segment and the hard segment first form a polyurea skeleton, specifically under the action of a chain extender; the chain extender includes one or more of p-phenylenediamine, m-phenylenediamine, diphenylmethanediamine, 1,4-cyclohexanediamine, and hexamethylenediamine.

7. The polyurea-based gel electrolyte as described in claim 1, characterized in that, The raw materials for preparing the polyurea-based gel electrolyte include polyetheramine, polyisocyanate, and eutectic solvent, wherein the molar ratio of the polyetheramine to the polyisocyanate is 1:(2-3).

8. The polyurea-based gel electrolyte as described in claim 1, characterized in that, The raw materials for preparing the polyurea-based gel electrolyte include polyetheramine, polyisocyanate, and eutectic solvent, and optionally include polyethylene oxide and chain extender. The molar ratio of the polyethylene oxide to the polyetheramine is (0-4):1; The total amount of the polyethylene oxide and the polyetheramine is in a molar ratio of 1:(2-3) to the polyisocyanate. The molar ratio of the chain extender to the polyisocyanate is (0-2):

1.

9. The method for preparing the polyurea-based gel electrolyte according to any one of claims 1-8, characterized in that, Includes the following steps: (1) Using polyetheramine as the soft segment raw material, the soft segment raw material and polyisocyanate are mixed in a solvent to carry out a polycondensation reaction to obtain isocyanate-terminated polyurea prepolymer; (2) The polyurea prepolymer obtained in step (1) is subjected to a chain extension reaction to obtain a polyurea skeleton material; (3) After dissolving the polyurea skeleton material obtained in step (2) in a mixed solvent of N,N-dimethylformamide and ethanol, a polyurea porous film is obtained by electrospinning. (4) Adding a eutectic solvent to the polyurea porous film obtained in step (3) will yield a polyurea-based gel electrolyte.

10. The preparation method according to claim 9, characterized in that, In step (3), the electrospinning process parameters are as follows: negative voltage 2~4 kV, positive voltage 7~16 kV; solution flow rate 0.1~0.5 ml / min. -1 The distance between the needle tip and the receiver tube should be 10-20 cm; the receiver tube rotation speed should be 40-80 rpm. -1 The polymer concentration is 10~20 wt%.

11. The preparation method according to claim 9, characterized in that, For the polycondensation reaction in step (1) and the chain extension reaction in step (2), the reaction temperature is 0~5 ℃ and the reaction time is controlled to be 12~24 h.

12. The preparation method according to claim 9, characterized in that, Step (1), the soft segment raw material also includes polyethylene oxide; Both the polyethylene oxide and the polyetheramine are aminopropyl-terminated. The polyisocyanate includes one or more of toluene diisocyanate, diphenylmethane diisocyanate, and terephthalic diisocyanate; The molar ratio of the polyethylene oxide to the polyetheramine is (1-4):1; The total amount of the polyethylene oxide and the polyetheramine is in a molar ratio of 1:(2-3) to the polyisocyanate. In step (2), the chain extension reaction specifically involves mixing the polyurea prepolymer with a chain extender in a solvent to carry out the chain extension reaction; the chain extender includes one or more of p-phenylenediamine, m-phenylenediamine, diphenylmethanediamine, 1,4-cyclohexanediamine, and hexamethylenediamine; the molar ratio of the chain extender to the remaining polyisocyanate in the system after the reaction in step (1) is 1:1; The solvent in step (1) and the solvent in step (2) are both N,N-dimethylformamide; In step (3), the mixed solvent of N,N-dimethylformamide and ethanol is specifically a mixed solvent obtained by N,N-dimethylformamide and ethanol in a volume ratio of 4:

1.

13. The preparation method according to claim 12, characterized in that, The molecular weight of the polyethylene oxide includes one or more of 800, 1000, 2000 and 4600; the molecular weight of the polyetheramine includes one or more of 230, 400, 1000 and 2000.

14. The application of the polyurea-based gel electrolyte as described in any one of claims 1-8 in the field of energy storage and ion skin.

15. The application as described in claim 14, characterized in that, Specifically, energy storage applications are used in lithium-ion batteries or lithium metal batteries.

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