A phase-changeable, high-conductivity ionic gel composite material, a preparation method and application thereof

Abstract

The application discloses a phase-changeable and high-conductivity ionic gel composite material and a preparation method thereof. The ionic gel composite material comprises a three-dimensional polymer network, an organic electrolyte lithium salt and a phase-changeable supersaturated solution. The three-dimensional polymer network is formed by cross-linking of hydrophobic and oleophobic monomers and is immersed in the phase-changeable supersaturated solution. The phase-changeable supersaturated solution is composed of a carbonate solute and an ionic liquid solvent. The ionic liquid solvent can dissolve the monomers and the polymer formed by cross-linking of the monomers. The organic electrolyte lithium salt is dissolved in the ionic liquid solvent. The ionic gel composite material has the advantages of modulus mutation, good flexibility, stable electrochemical performance, hydrophobicity and oleophobicity and high environmental stability and can be applied to the fields of impact-resistant solid-state polyelectrolyte materials and flexible electronic devices.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials technology, and specifically relates to an ion gel composite material with phase change capability and high conductivity, its preparation method and application. Background Technology

[0002] With the rapid development of electrochemical energy storage technology, researchers have begun to focus on improving the safety and stability of battery devices. Traditional liquid electrolytes suffer from problems such as easy leakage and encapsulation difficulties, making the development of non-liquid electrolytes a crucial research direction for improving the safety of electrochemical energy storage devices. Currently, common non-liquid electrolytes include ceramic electrolytes, polymer electrolytes, and hydrogel electrolytes. These non-liquid electrolytes offer advantages such as acting as a separator, bonding positive and negative electrodes to enhance electrode contact, and simplifying battery structure to improve encapsulation efficiency. However, common non-liquid electrolytes still face many problems and challenges. For example, ceramic electrolytes suffer from poor interfacial compatibility; polymer electrolytes have low ionic conductivity; and hydrogel electrolytes face challenges such as low voltage window, narrow operating temperature range, and low mechanical strength. Therefore, how to prepare an electrolyte with excellent comprehensive performance has become a common issue that electrochemical energy storage researchers need to address.

[0003] In recent years, gel electrolytes, with their advantages of flexibility, stretchability, and ionic conductivity, have been widely used in the field of electrochemical energy storage, and can be fabricated into batteries of various shapes, flexible batteries, and thin-film batteries. Compared with liquid electrolytes, solid gel electrolytes are safer and will not explode when subjected to abnormal use conditions such as overcharging, over-discharging, impact, crushing, and puncture. However, the ionic conductivity of gel electrolytes at room temperature is only a fraction or even a few tens of times that of liquid electrolytes, resulting in poor high-rate charge-discharge performance and low-temperature performance. Moreover, their mechanical properties are relatively low, making it difficult to surpass those of polyolefin separators, which also leads to poor stability during battery use. Therefore, developing a gel electrolyte with good mechanical properties and high conductivity is an urgent need in the field of flexible electronics. Summary of the Invention

[0004] In order to overcome the shortcomings of the prior art, the present invention aims to provide a phase-changeable, highly conductive ion gel composite material, its preparation method and application, so as to optimize the mechanical properties of the ion gel composite material and obtain high conductivity.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] The first objective of this invention is to provide a phase-change-capable, highly conductive ionogel composite material, comprising a three-dimensional polymer network, an organic electrolyte lithium salt, and a phase-change-capable supersaturated solution; the three-dimensional polymer network is formed by cross-linking hydrophobic and oleophobic monomers and is immersed in the phase-change-capable supersaturated solution; the phase-change-capable supersaturated solution is composed of a carbonate solute and an ionic liquid solvent, the ionic liquid solvent being capable of dissolving the monomers and the polymer formed by cross-linking the monomers, and the organic electrolyte lithium salt being dissolved in the ionic liquid solvent.

[0007] In one embodiment, the ion gel composite material is composed of the three-dimensional polymer network, the organic electrolyte lithium salt, and the phase-change supersaturated solution.

[0008] In one embodiment, the monomer is one or more of ethyl acrylate (EA), butyl acrylate (BA), tert-butyl acrylate (TBA), methyl methacrylate (MMA), and tetrahydrofuran acrylate (THFA); the organic electrolyte lithium salt is one or more of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium dioxolane borate (LiBOB), lithium difluorooxolane borate (LiDFOB), lithium bis(fluorosulfonyl)imide (LiFSI), and lithium difluorophosphate (LiPO2F2), possessing the characteristics of hydrophobicity, oleophobicity, and high environmental stability.

[0009] In one embodiment, the carbonate solute is a cyclic carbonate and / or a chain carbonate; the ionic liquid solvent is an ionic liquid containing a (trifluoromethanesulfonyl)imide anionic group.

[0010] In one embodiment, the three-dimensional polymer network accounts for 1 wt% to 50 wt% of the total mass of the ionogel composite material. Adjusting the amount of the three-dimensional polymer network allows for the adjustment of the composite material's strength, tensile strain, and other mechanical properties. The solubility of the organic electrolyte lithium salt in the phase-change supersaturated solution is 0.1 to 2 mol / L. Adjusting the amount of the organic electrolyte lithium salt allows for the adjustment of the composite material's conductivity. The solute in the phase-change supersaturated solution accounts for 1 wt% to 99 wt% of the solution mass ratio. Adjusting this mass ratio allows for the adjustment of the composite material's mechanical and electrical properties before and after the phase change. It is noteworthy that during the preparation of the prepolymer solution, by increasing the temperature, the solute concentration in all mass ratios (1%-99%) of the solution at temperatures above room temperature did not exceed the solubility of the solute at that temperature and pressure; therefore, it was not a supersaturated state. The ionogel obtained by polymerization at temperatures above room temperature is then placed at room temperature. Only when the solute concentration exceeds the solubility of the solute at room temperature and pressure does it become a supersaturated solution.

[0011] In one embodiment, the carbonate solute is one or more of dimethyl carbonate (DMC), diethyl carbonate (DEC), methyl ethyl carbonate (EMC), ethylene carbonate (EC), and propylene carbonate (PC); the ionic liquid solvent is one or more of monosubstituted imidazole ionic liquids, disubstituted imidazole ionic liquids, trisubstituted imidazole ionic liquids, and amino-functionalized ionic liquids, possessing hydrophobic and oleophobic properties. A second objective of this invention is to provide a method for preparing a phase-change-capable, highly conductive ionogel composite material, comprising the following steps:

[0012] Step 1: Dissolve the monomer and organic electrolyte lithium salt in a solution composed of carbonate solute and ionic liquid solvent in an environment above room temperature;

[0013] Step 2: Add initiator and crosslinking agent, and polymerize in an environment above room temperature to obtain ionogel;

[0014] Step 3: Place the ion gel at room temperature to allow the carbonate solute and ionic liquid solvent in the gel network to reach a supersaturated state, thereby obtaining an ion gel composite material with phase change capability and high conductivity.

[0015] Step 4: A phase transition is initiated by the supersaturated solution, which increases the modulus and decreases the conductivity of the ion gel composite material obtained in Step 3. Then, the phase transition effect is eliminated to restore its modulus and conductivity.

[0016] In one embodiment, in step 2, the polymerization reaction is initiated by photoinitiation or radiation initiation; in step 4, the phase change effect is eliminated by heating.

[0017] In one embodiment, in step 4, a phase transition is achieved by applying external force or introducing solid seed crystals to precipitate the supersaturated solution.

[0018] The third objective of this invention is to provide applications of phase-change, highly conductive ionogel composite materials in impact-resistant solid polyelectrolyte materials and the phase-change, highly conductive ionogel composite materials described in the claims as impact-resistant solid polyelectrolytes and flexible substrates, flexible electrodes, flexible wires, etc., of flexible electronic devices.

[0019] Compared with existing technologies, the ionogel composite material of the present invention has properties such as modulus abrupt change, good flexibility, and stable electrochemical performance, while also possessing the advantages of hydrophobicity, oleophobicity, and high environmental stability. The phase-change, high-conductivity ionogel provided by the present invention can be applied to impact-resistant solid polyelectrolyte materials and the phase-change, high-conductivity ionogel composite material described in the claims as impact-resistant solid polyelectrolytes and flexible electronic device structures such as flexible substrates, flexible electrodes, and flexible wires. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the ion gel composite material model of the present invention.

[0021] Figure 2 Differential scanning calorimetry (DSC) curves for EC / IL solutions with different mass ratios are shown.

[0022] Figure 3 This image illustrates the transparency of phase-change, highly conductive ion-gel composites with different EC / IL solution mass ratios.

[0023] Figure 4 Uniaxial tensile stress-strain curves and elastic moduli of ionogel composites with phase change and high conductivity for different EC / IL solution mass ratios.

[0024] Figure 5 The mass ratio of three EC / IL solutions (V) EC / IL Cyclic loading and unloading stress-strain curves of phase-change, highly conductive ionogel composites with ratios of 1:9, 6:4, and 5:5.

[0025] Figure 6 Before and after 30 seconds of recovery, the phase-change, highly conductive ionogel composite material (V) exhibits [significant changes]. EC / IL =8:2) Cyclic loading and unloading stress-strain curve.

[0026] Figure 7 The uniaxial tensile stress-strain curves of phase-changeable, highly conductive ionogel composites with different EC / IL solution mass ratios before and after phase transformation crystallization are shown.

[0027] Figure 8 Conductivity of phase-change, high-conductivity ion gel composites with different EC / IL solution mass ratios.

[0028] Figure 9 The conductivity of phase-change, high-conductivity ion gel composites with different EC / IL solution mass ratios after phase transformation crystallization is determined. Detailed Implementation

[0029] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings and examples.

[0030] refer to Figure 1This invention provides a phase-change-capable, highly conductive ionogel composite material, comprising a three-dimensional polymer network, an organic electrolyte lithium salt, and a phase-change-capable supersaturated solution, or alternatively, consisting only of the three-dimensional polymer network, the organic electrolyte lithium salt, and the phase-change-capable supersaturated solution. The three-dimensional polymer network is formed by crosslinking hydrophobic and oleophobic monomers and is immersed in the phase-change-capable supersaturated solution. The phase-change-capable supersaturated solution is composed of a carbonate solute and an ionic liquid solvent, wherein the ionic liquid solvent can dissolve the monomers and the polymer formed by the crosslinking of the monomers, and the organic electrolyte lithium salt is dissolved in the ionic liquid solvent. The polymer network of this invention imparts flexibility and hydrophobicity / oleophobicity to the material. The phase-change-capable properties are provided by introducing a carbonate solute and an ionic liquid to the ionogel network to form a supersaturated solution, thereby achieving a high-to-low reversible change in modulus and conductivity. The addition of the organic electrolyte lithium salt provides high conductivity.

[0031] In some embodiments of the present invention:

[0032] The monomers of the cross-linked hydrophobic and oleophobic polymer network are selected from one or more materials such as ethyl acrylate (EA), butyl acrylate (BA), tert-butyl acrylate (TBA), methyl methacrylate (MMA), and tetrahydrofuran acrylate (THFA).

[0033] The organic electrolyte lithium salt is one or more of the following materials: lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium dioxalate borate (LiBOB), lithium difluorooxalate borate (LiDFOB), lithium bis(fluorosulfonyl)imide (LiFSI), and lithium difluorophosphate (LiPO2F2).

[0034] The carbonate solute is a cyclic carbonate and / or a chain carbonate, such as one or more of dimethyl carbonate (DMC), diethyl carbonate (DEC), methyl ethyl carbonate (EMC), ethylene carbonate (EC), and propylene carbonate (PC); the ionic liquid solvent is one or more of monosubstituted imidazole ionic liquids such as N-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, disubstituted imidazole ionic liquids such as 1,3-dimethylimidazolium bis(trifluoromethanesulfonyl)imide salt, trisubstituted imidazole ionic liquids such as 1-ethyl-2,3-dimethylimidazolium bis(trifluoromethanesulfonyl)imide salt, and amino-functionalized ionic liquids such as 1-aminopropyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt. The above-mentioned ionic liquids containing (trifluoromethanesulfonyl)imide anionic groups are both hydrophobic and oleophobic, and can dissolve monomers, making them excellent solvents for the composite gel materials of this invention.

[0035] In another aspect, the present invention provides a method for preparing the above-mentioned phase-change-capable, highly conductive ion gel composite material, the specific steps of which include:

[0036] (a) First, the monomer and organic electrolyte lithium salt are dissolved in a solution composed of carbonate solute and ionic liquid solvent in an environment above room temperature;

[0037] (b) Then, an initiator and a crosslinking agent are added to the mixed solution obtained in step (a), and polymerization is initiated in an environment above room temperature by means of photoinitiation or radiation initiation to obtain an ionogel;

[0038] (c) The ionogel obtained in step (b) is then placed at room temperature to allow the carbonate solute and ionic liquid solvent in the gel network to reach a supersaturated state, resulting in a phase-change-capable, highly conductive ionogel composite material. The initiator used can be selected from 2-hydroxy-2-methyl-1-phenyl-1-propanone (UV1173), 1-hydroxycyclohexylphenyl ketone (UV184), 2-methyl-1-(4-methylthiophenyl)-2-morpholino-1-propanone (UV907), 2-phenylbenzyl-2-dimethylamine-1-(4-morpholinobenzylphenyl)butanone (UV369), α-ketoglutaric acid, 2-hydroxy-2-methyl-1-phenylpropanone, methyl benzoylformate, or alkyl iodonium salts, etc. The amount of initiator added can be 0.01%-1% of the total weight of the ionogel.

[0039] (d) Next, by applying external force or introducing solid "seed crystals" to induce precipitation in a supersaturated solution, a phase transition is achieved in the supersaturated solution, resulting in an increase in modulus and a decrease in conductivity in the ionogel composite material obtained in step (c). Finally, the phase transition effect is eliminated by methods such as high-temperature heating, restoring the ionogel composite material with low modulus and high conductivity obtained in step c.

[0040] The phase-change-capable, highly conductive ionogel composite material prepared using the above method consists of a polymer network and a phase-change-capable supersaturated ionic liquid solution. A supersaturated solution is a thermodynamically unstable state, where the concentration of carbonate solutes in the ionic liquid exceeds their solubility at room temperature, yet the carbonates have not precipitated. Under external stimuli, the excess carbonates in the ionic liquid immediately crystallize and precipitate, causing the solution to solidify rapidly. This results in an increase in the modulus and a decrease in the conductivity of the ionogel composite material. Subsequently, by increasing the temperature, the solubility of the carbonates in the ionic liquid can be increased, allowing the material to completely revert to its phase-change-capable, highly conductive ionogel composite material state.

[0041] Therefore, the physical structure of the prepared phase-changeable, high-conductivity ion gel composite material is closely related to its properties. For example, the polymer network imparts flexibility and hydrophobicity and oleophobicity to the material, while the phase-changeable supersaturated solution is used to achieve high-low reversible changes in modulus and conductivity.

[0042] This invention utilizes the principle of supersaturated crystallization of soluble solutes (such as carbonates) to develop a novel "crystalline ionic gel" based on ordinary ionic gels, and studies its mechanical, electrical, and thermal properties. The standard dumbbell shape (12×2×35mm) was tested using an electronic universal testing machine. 3 Uniaxial tensile tests were performed on samples of [material name], ensuring the entire test was conducted at room temperature and a uniform tensile rate of 100 mm / min. The resulting material exhibited a tensile strength of 0.5–1.5 MPa (2–10 times elongation) and a tensile modulus as high as 10–100 MPa, demonstrating mechanical properties generally superior to most gel electrolytes. A four-point probe method was used to test elongated samples (50 × 7.5 × 2 mm). 3 Tests were conducted, and the conductivity was found to be up to 10. -3 ~10 -2 S / cm, the conductivity rapidly decreases to 10 after phase transformation crystallization. -6 ~10 -5 S / cm. The preparation of this crystalline ionogel mainly involves two steps. First, excess solute is dissolved in the precursor solution by heating, forming an ionogel containing supersaturated solute. Then, by applying external force or introducing seed crystals, the supersaturated solute inside the ionogel is oriented to crystallize, resulting in a crystalline ionogel. Compared with other non-liquid electrolytes, crystalline ionogels have many advantages and exhibit excellent comprehensive performance.

[0043] The technical solution adopted in this invention is to apply the prepared phase-change, high-conductivity ion gel composite material to the fields of impact-resistant solid polyelectrolyte materials and flexible electronic devices.

[0044] Furthermore, the solid polyelectrolyte material can be applied in the field of solid-state lithium batteries as a separator material for lithium-ion batteries. When subjected to external force, the modulus of the separator increases, resulting in high battery safety and strong stability.

[0045] Furthermore, the aforementioned flexible substrates, flexible electrodes, flexible wires, and other materials can be applied to flexible electronic devices such as wearable devices, flexible robots, and electronic skin. These materials possess advantages such as easy availability, chemical stability, transparency, and good thermal stability, meeting the requirements of flexible electronic devices for flexibility, stretchability, and bendability. Flexible substrate materials can be used to design circuits to fabricate flexible thin-film electronic devices that can withstand bending, folding, torsion, compression, stretching, and complex deformations. Flexible electrode materials can be applied to flexible batteries and integrated with stretchable devices to create flexible electronic devices, leading to rapid development in wearable devices, medical devices, and flexible robots.

[0046] The following are some specific embodiments of the present invention.

[0047] Example 1

[0048] This embodiment includes the following steps: Step 1: First, 2.49g of ethylene carbonate (EC, 1.32g / cm³) is placed in an environment above room temperature (45-90℃). 3 Dissolving it in 0.21 mL of 1-butyl-2,3-dimethylimidazolium bis(trifluoromethanesulfonyl)imide salt ionic liquid yields a solution that is supersaturated at room temperature, such as... Figure 2 While maintaining a high temperature environment, dissolve 2.9 mL of tert-butyl acrylate monomer (TBA) and 0.6 g of lithium bis(trifluoromethanesulfonyl)imide organic lithium salt (LiTFSI, Mn = 287.08) in an EC / IL supersaturated solution.

[0049] Step 2: Add 0.0204 g (Mw = 204.26, 0.0001 mol) of 1-hydroxycyclohexyl benzophenone initiator and 20 μL (0.1 mol% TBA) of ethylene glycol dimethacrylate (Mw = 575) crosslinking agent to the mixed solution, and dissolve evenly under high temperature. Pour the prepared solution into a glass mold and place it under a UV lamp for 1 hour to obtain an ionogel (M... EC / IL =9:1). The obtained ionogel was then left to stand at room temperature (20–25°C) for 12 hours to obtain a phase-change ionogel composite material with high conductivity, such as... Figure 3 .

[0050] Step 3: Apply strong external force to the left or right edge of the ionogel composite material using a glass rod. EC will rapidly precipitate and crystallize along the pressed area, gradually spreading to the entire material, becoming a phase change crystallized ionogel composite material. Finally, placing the phase change crystallized gel in an environment of 45–90°C for 24 hours will eliminate the phase change effect and restore it to an ionogel.

[0051] Example 2

[0052] This embodiment includes the following steps: Step 1: First, 1.386g of ethylene carbonate (EC, 1.32g / cm³) is placed in an environment above room temperature (45-90℃). 3 A solution that can remain supersaturated at room temperature was prepared by dissolving 1.05 mL of monosubstituted imidazole ionic liquid such as N-methylimidazolium bis(trifluoromethanesulfonyl)imide salt. While maintaining a high temperature environment, 2.9 mL of tert-butyl acrylate monomer (TBA) and 0.6 g of lithium bis(trifluoromethanesulfonyl)imide organic lithium salt (LiTFSI, Mn = 287.08) were dissolved in an EC / IL supersaturated solution.

[0053] Step 2: Add 0.0204 g (Mw = 204.26, 0.0001 mol) of 1-hydroxycyclohexyl benzophenone initiator and 20 μL (0.1 mol% TBA) of ethylene glycol dimethacrylate (Mw = 575) crosslinking agent to the mixed solution, and dissolve evenly under high temperature. Pour the prepared solution into a glass mold and place it under a UV lamp for 1 hour to obtain an ionogel (M... EC / IL =5:5). The obtained ionogel was then placed in a room temperature environment of 20-25℃ for 12 hours to obtain an ionogel composite material with phase change capability and high conductivity.

[0054] Step 3: Apply strong external force to the left or right edge of the ionogel composite material using a glass rod. EC will rapidly precipitate and crystallize along the pressed area, gradually spreading to the entire material, becoming a phase change crystallized ionogel composite material. Finally, placing the phase change crystallized gel in an environment of 45–90°C for 24 hours will eliminate the phase change effect and restore it to an ionogel.

[0055] Example 3

[0056] This embodiment includes the following steps: Step 1: First, at a temperature higher than room temperature (45-90℃), 1.06g of methyl ethyl carbonate (EMC, 1.01g / cm³) is added... 3 A solution that can remain supersaturated at room temperature was prepared by dissolving 1.05 mL of 1-butyl-2,3-dimethylimidazolium bis(trifluoromethanesulfonyl)imide ionic liquid. While maintaining a high temperature environment, 2.9 mL of ethyl acrylate monomer (EA) and 0.6 g of lithium bis(trifluoromethanesulfonyl)imide organic lithium salt (LiTFSI, Mn = 287.08) were dissolved in an EC / IL supersaturated solution.

[0057] Step 2: Add 0.0204 g (Mw = 204.26, 0.0001 mol) of 1-hydroxycyclohexyl benzophenone initiator and 20 μL (0.1 mol% TBA) of ethylene glycol dimethacrylate (Mw = 575) crosslinking agent to the mixed solution, and dissolve evenly under high temperature. Pour the prepared solution into a glass mold and place it under a UV lamp for 1 hour to obtain an ionogel (M... EMC / IL =5:5). The obtained ionogel was then placed in a room temperature environment of 20-25℃ for 12 hours to obtain an ionogel composite material with phase change capability and high conductivity.

[0058] Step 3: Apply strong external force to the left or right edge of the ionogel composite material using a glass rod. EMC will rapidly precipitate and crystallize along the pressed area, gradually spreading to the entire material, becoming a phase change crystallized ionogel composite material. Finally, placing the phase change crystallized gel in an environment of 45–90℃ for 24 hours will eliminate the phase change effect and restore it to an ionogel.

[0059] Figure 2 For solutions with different mass ratios of EC / IL (M EC / IL Differential scanning calorimetry (DSC) curves (100%, 90%, 80%, 70%, 60%, 50%, 10%, 0%) were obtained. The results showed that the melting peak of the pure EI solution was at 38℃, and the crystallization peak after heating to eliminate thermal history and then cooling was at -6℃. When EI was dissolved in IL to prepare an EC / IL solution, the EC / IL mass ratio gradually decreased with increasing IL content, resulting in lower melting and crystallization peaks. When the EC / IL solution mass ratio was less than 70%, it could remain liquid at room temperature, but crystallization required a temperature below -30℃.

[0060] Figure 3 For solutions with different mass ratios of EC / IL (M EC / IL Transparency visualization of ionomer composites with phase change capability and high conductivity prepared at concentrations of 100%, 90%, 80%, 70%, 60%, 50%, 40%, 30%, 20%, 10%, and 0%). It can be seen that the pure ionomer (M...)... EC / IL =0%) is transparent, as M EC / IL As the concentration increases, the material gradually becomes translucent. This is because the ECs in contact with the polymer chains form micro- and nano-crystalline regions, resulting in the translucent state of the ionogel composite material within the visible light range.

[0061] Figure 4 For EC / IL solutions with different mass ratios (M EC / IL Uniaxial tensile stress-strain curves and elastic moduli of ionogel composites with phase change capability and high conductivity (prepared at concentrations of 100%, 90%, 80%, 70%, 60%, 50%, 40%, 30%, 20%, 10%, and 0%) were obtained. The results showed that the fracture stress of the EC / IL ionogel composites was 0.5–1.5 MPa (2–10 times elongation), and the modulus was as high as 10–100 MPa. EC forms micro / nanocrystalline regions around the polymer chains, increasing the rigidity of the polymer chains. With the increase of M... EC / IL With increased concentration, the strength of ionogel composites increases while their tensile strength decreases.

[0062] Figure 5 The mass ratio of three EC / IL solutions (M) EC / IL Cyclic loading-unloading stress-strain curves of ionogel composites with phase change capability and high conductivity (60%, 50%, and 10%) were obtained. The results show that the ionogel composites exhibit stress-strain variation with M... EC / IL The increase exhibits significant energy dissipation, i.e., a hysteresis phenomenon in the unloading curve. Calculations show that the larger the hysteresis loop, the greater the energy dissipation at strain 2.0. EC / IL =The dissipated energy of 60% of the samples is 0.40 MJ / m².-3 M EC / IL =The dissipated energy of 50% of the sample is 0.13 MJ / m². -3 M EC / IL =The dissipated energy of 10% of the sample is 0.016 MJ m -3 This set of data shows that before the material is damaged, as M... EC / IL With increasing M, the dissipation energy of the ionogel composite material increases significantly. This is because M... EC / IL The rigidity of the polymer chain is affected; the greater the rigidity of the polymer chain, the higher the energy dissipated.

[0063] Figure 6 For the phase change, high conductivity ion gel composite material (M) before and after 30 seconds of recovery. EC / IL =80%) underwent 10 cycles of loading and unloading stress-strain curves at a strain of 1.0. The results show that after a rest time of 30 s, the maximum stress of the ionogel composite material is 0.4 MPa, which is smaller than that of the original ionogel (maximum stress of 0.56 MPa), and the stress-strain curves of the material after a 30 s rest are all below the cyclic curves of the original ionogel. This indicates that the observed inelastic deformation is due to polymer chain breakage.

[0064] Figure 7 For solutions with different mass ratios of EC / IL (M) before and after phase transition crystallization EC / IL Uniaxial tensile stress-strain curves of ionogel composites with phase transformation capability and high conductivity (prepared at concentrations of 100%, 90%, 80%, 70%, 60%, 50%, 40%, 30%, 20%, 10%, and 0%) were displayed. The results show that the strength of the ionogel composites after phase transformation crystallization is significantly higher than that of the homogeneous material without phase transformation, and this strength increases with increasing M. EC / IL The more significant the change in intensity before and after the phase transition, the better.

[0065] Figure 8 For solutions with different mass ratios of EC / IL (M EC / IL The conductivity of ionogel composites with phase change capability and high conductivity (prepared at concentrations of 100%, 90%, 80%, 70%, 60%, 50%, 40%, 30%, 20%, 10%, and 0%) was measured. The asymmetry of certain substituents in imidazole-based ion liquids prevents ions from stacking regularly, creating rapid ion migration channels that conduct electricity under applied voltage. EC has a high dielectric constant, which is beneficial for ion conduction. The conductivity of the ionogels was tested using a four-point probe method, achieving a value of 10. -3 ~10 -2 S / cm. Ion gel composite material (M EC / ILThe conductivity of the EC / IL solution (60%) was 0.012 S / cm, indicating that EC and IL can synergistically enhance ion migration and improve the conductivity of the EC / IL solution.

[0066] Figure 9 After phase transformation crystallization, solutions with different mass ratios of EC / IL (M EC / IL The conductivity of ionomer-based composite materials with phase change capability and high conductivity (prepared at concentrations of 100%, 90%, 80%, 70%, 60%, 50%, 40%, 30%, 20%, 10%, and 0%) is shown. The conductivity rapidly decreases to 10 after phase change crystallization. -6 ~10 -5 S / cm, such as Figure 9 But with M EC / IL When the content of EC increases to 50%–90%, EC forms micro / nanocrystalline regions around the polymer chains, thereby enhancing the conductivity of the polymer chains. Ion gel composites (M... EC / IL The conductivity of the ion gel composite material (60%) is 0.0017 S / cm, which indicates that the crystalline region formed by EC around the polymer chain facilitates the migration of IL ions and enhances the conductivity of the ion gel composite material.

[0067] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A phase-change-capable, highly conductive ionogel composite material, characterized in that, The process includes a three-dimensional polymer network, an organic electrolyte lithium salt, and a phase-change supersaturated solution. The three-dimensional polymer network is formed by crosslinking hydrophobic and oleophobic monomers. The phase-change supersaturated solution consists of a carbonate solute and an ionic liquid solvent, wherein the ionic liquid solvent can dissolve the monomers, and the organic electrolyte lithium salt is dissolved in the ionic liquid solvent. The monomers and the organic electrolyte lithium salt are dissolved in the solution composed of the carbonate solute and the ionic liquid solvent in an environment above room temperature. An initiator and a crosslinking agent are added. During the preparation of the prepolymer solution, the temperature is increased so that the solution composed of the carbonate solute and the ionic liquid solvent is not in a supersaturated state in an environment above room temperature. Polymerization is carried out in an environment above room temperature to obtain an ionic gel. The ionic gel is placed in an environment at room temperature so that the carbonate solute and the ionic liquid solvent in the gel network reach a supersaturated state, resulting in a phase-change, highly conductive ionic gel composite material.

2. The phase-change-capable, highly conductive ionogel composite material according to claim 1, characterized in that, The ion gel composite material is composed of the three-dimensional polymer network, the organic electrolyte lithium salt, and the phase-change supersaturated solution.

3. The phase-change-capable, highly conductive ionogel composite material according to claim 1 or 2, characterized in that, The monomer is one or more of ethyl acrylate, butyl acrylate, tert-butyl acrylate, methyl methacrylate, and tetrahydrofuran acrylate; the organic electrolyte lithium salt is one or more of lithium bis(trifluoromethanesulfonyl)imide, lithium hexafluorophosphate, lithium tetrafluoroborate, lithium dioxalate borate, lithium difluorooxalate borate, lithium bis(fluorosulfonyl)imide, and lithium difluorophosphate.

4. The phase-change-capable, highly conductive ionogel composite material according to claim 1 or 2, characterized in that, The carbonate solute is a cyclic carbonate and / or a chain carbonate; the ionic liquid solvent is an ionic liquid containing a (trifluoromethanesulfonyl)imide anionic group.

5. The phase-change-capable, highly conductive ionogel composite material according to claim 1 or 2, characterized in that, In the ion gel composite material, the three-dimensional polymer network accounts for 1 wt% to 50 wt% of the total mass of the ion gel composite material, the solubility of the organic electrolyte lithium salt in the phase change supersaturated solution is 0.1 to 2 mol / L, and the solute in the phase change supersaturated solution accounts for 1 wt% to 99 wt% of the solution mass.

6. The phase-change-capable, highly conductive ionogel composite material according to claim 1 or 2, characterized in that, The carbonate solute is one or more of dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, ethylene carbonate, and propylene carbonate; the ionic liquid solvent is one or more of monosubstituted imidazole ionic liquid, disubstituted imidazole ionic liquid, trisubstituted imidazole ionic liquid, and amino-functionalized ionic liquid.

7. A method for preparing the phase-change-capable, highly conductive ionogel composite material according to any one of claims 1 to 6, characterized in that, Includes the following steps: Step 1: Dissolve the monomer and organic electrolyte lithium salt in a solution composed of carbonate solute and ionic liquid solvent in an environment above room temperature; Step 2: Add initiator and crosslinking agent, and polymerize in an environment above room temperature to obtain ionogel; Step 3: Place the ion gel at room temperature to allow the carbonate solute and ionic liquid solvent in the gel network to reach a supersaturated state, thereby obtaining an ion gel composite material with phase change capability and high conductivity. Step 4: A phase transition is initiated by the supersaturated solution, which increases the modulus and decreases the conductivity of the ion gel composite material obtained in Step 3. Then, the phase transition effect is eliminated to restore its modulus and conductivity.

8. The method according to claim 7, characterized in that, In step 2, the polymerization reaction is initiated by photoinitiation or radiation initiation; in step 4, the phase change effect is eliminated by heating.

9. The method according to claim 7 or 8, characterized in that, In step 4, a phase transition is achieved by applying external force or introducing solid seed crystals to precipitate the supersaturated solution.

10. The application of the phase-change-capable, highly conductive ionogel composite material according to any one of claims 1 to 6 as an impact-resistant solid polyelectrolyte and a flexible substrate, flexible electrode, or flexible wire for flexible electronic devices.

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