A dual-network interpenetrated shape memory solid-state electrolyte and a preparation method thereof

Abstract

The application provides a preparation method of a double-network interpenetrating shape memory solid electrolyte, and the preparation method comprises the following steps: (1) adding a first functional monomer, a polymer electrolyte monomer and a macroinitiator into a first organic solvent to carry out mixing reaction, so as to obtain an ion conductive polymer network glue; and (2) adding the ion conductive polymer network glue, a second functional monomer, a crosslinking agent and an electrolyte lithium salt into a second organic solvent to carry out mixing crosslinking, so as to obtain the double-network interpenetrating shape memory solid electrolyte. The solid polymer electrolyte in the application is obtained by interpenetrating and crosslinking a shape memory polymer network and an ion conductive polymer network, and not only has high ion conductivity and high strength, but also allows uniform current distribution to effectively inhibit lithium dendrite growth; meanwhile, the solid polymer electrolyte also has a shape memory intelligent carrier function, and can meet the demand of the aerospace field for multifunctional intelligent materials.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of polymer electrolyte, in particular to a double-network interpenetrating shape memory solid-state electrolyte and a preparation method thereof. BACKGROUND

[0002] With the development of new energy vehicles and other fields, higher requirements are put forward for lithium ion batteries, especially in terms of high power, high energy density and high safety performance. At present, the commercialized lithium ion battery generally uses flammable, explosive and volatile organic electrolyte, which has extremely high safety hazard. In addition, the growth of lithium dendrites in the liquid electrolyte also hinders the practical application of lithium metal anode in rechargeable batteries. In order to cope with these challenges, using all-solid-state electrolyte to replace electrolyte containing organic liquid is an important way to solve the safety problem of battery.

[0003] At present, the all-solid-state electrolyte studied more mainly includes polymer-based electrolyte, inorganic oxide electrolyte, sulfide electrolyte and organic-inorganic composite electrolyte. However, the above all-solid-state electrolyte has single function, and it is difficult to have electrolyte function and shape memory performance, so it cannot meet the demand of aerospace field for multifunctional intelligent materials.

[0004] Therefore, based on the above problems, it is urgent to provide a double-network interpenetrating shape memory solid-state electrolyte and a preparation method thereof. SUMMARY

[0005] The embodiment of the present application provides a double-network interpenetrating shape memory solid-state electrolyte and a preparation method thereof, which can solve the problem that the solid-state electrolyte in the prior art has single function and is difficult to meet the demand of aerospace field for multifunctional intelligent materials.

[0006] In a first aspect, the present application provides a preparation method of a double-network interpenetrating shape memory solid-state electrolyte, which comprises the following steps:

[0007] (1) mixing and reacting a first functional monomer, a polymer electrolyte monomer and a macromolecular initiator in a first organic solvent to obtain an ion conductive polymer network colloid; wherein the first functional monomer comprises an epoxy group and a carbon-carbon double bond;

[0008] (2) mixing and cross-linking the ion conductive polymer network colloid, a second functional monomer, a cross-linking agent and an electrolyte lithium salt in a second organic solvent to obtain the double-network interpenetrating shape memory solid-state electrolyte; wherein the second functional monomer comprises an epoxy group.

[0009] Preferably, in step (1), the first functional monomer is glycidyl methacrylate; the polymer electrolyte monomer is poly(ethylene glycol) methyl ether methacrylate; the macromolecular initiator is tetrahydroxymethylpropane tris(2-bromoisobutyrate) or trihydroxymethylpropane tris(2-bromoisobutyrate); and the first organic solvent is toluene or ethylbenzene.

[0010] Preferably, the second functional monomer is bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, epoxy phenolic resin, or bisphenol S diglycidyl ether; the crosslinking agent is polyetheramine, polyetherdiamine, or polyethertriamine; the electrolyte lithium salt is lithium bis(trifluoromethanesulfonyl)imide, lithium bis(fluorosulfonyl)imide, lithium difluorooxalateborate, or lithium dioxalateborate; and the second organic solvent is acetonitrile solution.

[0011] Preferably, in step (1), during the preparation of the ion-conducting polymer network colloid, the content of the first functional monomer is 1-10% by weight, the content of the polymer electrolyte monomer is 60-90%, the content of the macromolecular initiator is 0.1-2%, and the content of the first organic solvent is 2-15%.

[0012] Preferably, in step (2), the mass ratio of the ion-conducting polymer network colloid to the second functional monomer is 1:(1-3); the content of the crosslinking agent is 20-25% of the total amount of the ion-conducting polymer network colloid and the second functional monomer.

[0013] In the preparation of the dual-network interpenetrating shape memory solid electrolyte, the content of the electrolyte lithium salt is 0.5-1% by weight, and the content of the second organic solvent is 10-20%.

[0014] Preferably, in step (2), before the crosslinking reaction, a step of adding a catalytic monomer to the reaction system is further included; wherein the catalytic monomer includes 1,1,4,7,10,10-hexamethyltriethylenetetramine and copper bromide.

[0015] Preferably, the content of the catalytic monomer is 0.2-4% by weight.

[0016] Preferably, the reaction temperature is 70-80℃ and the time is 2-6h.

[0017] Preferably, in step (2), the crosslinking temperature is 15-25℃ and the time is 10-12h.

[0018] Secondly, the present invention also provides a shape memory solid electrolyte with dual interpenetrating networks, which is prepared by the preparation method described in any one of the first aspects above.

[0019] Thirdly, the present invention also provides an application of a shape memory solid electrolyte with dual interpenetrating networks prepared by any of the preparation methods described in the first aspect or the shape memory solid electrolyte with dual interpenetrating networks described in the second aspect in a lithium battery.

[0020] Compared with the prior art, the present invention has at least the following beneficial effects:

[0021] In this invention, a first functional monomer containing epoxy groups and carbon-carbon double bonds, along with a polymer electrolyte monomer, are reacted under the action of a macromolecular initiator to form an ionicly conductive polymer network colloid with high strength and ionic conductivity. Then, based on this network colloid, a second functional monomer containing epoxy groups and an electrolyte lithium salt are added and further reacted under the action of a crosslinking agent. The second functional monomer reacts first with the crosslinking agent to form a polymer network with shape memory properties. This polymer network can then further interpenetrate and crosslink with the ionicly conductive polymer network, forming a double-network interpenetrating shape memory solid electrolyte. Thus, the double-network interpenetrating solid polymer electrolyte obtained in this invention not only exhibits high ionic conductivity and high strength but also allows for uniform current distribution to effectively suppress lithium dendrite growth. Simultaneously, this solid polymer electrolyte also possesses shape memory intelligent carrier functionality, exhibits good compatibility with the cathode, and can meet the needs of the aerospace field for multifunctional intelligent materials. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the structure of a shape memory solid electrolyte with dual interpenetrating networks provided in an embodiment of the present invention; the black network is a polymer network structure with shape memory function, and the gray dashed network is an ion conductivity polymer network structure. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0025] This invention provides a method for preparing a shape memory solid electrolyte with interpenetrating dual networks, the method comprising the following steps:

[0026] (1) The first functional monomer, the polymer electrolyte monomer and the macromolecular initiator are added to the first organic solvent and mixed and reacted to obtain an ion-conducting polymer network colloid; wherein the first functional monomer contains an epoxy group and a carbon-carbon double bond;

[0027] (2) The ion-conducting polymer network colloid, the second functional monomer, the crosslinking agent and the electrolyte lithium salt are added to the second organic solvent and mixed and crosslinked to obtain the shape memory solid electrolyte with the double network interpenetration; wherein the second functional monomer contains epoxy groups.

[0028] In this embodiment of the invention, a first functional monomer containing epoxy groups and carbon-carbon double bonds, and a polymer electrolyte monomer are first reacted with a macromolecular initiator to form an ionicly conductive polymer network colloid with high ionic conductivity and strength. Then, based on this network colloid, a second functional monomer containing epoxy groups and an electrolyte lithium salt are added and further reacted under the action of a crosslinking agent. The second functional monomer reacts first with the crosslinking agent to form a polymer network with shape memory properties. This polymer network can then further interpenetrate and crosslink with the ionicly conductive polymer network, forming a double-network interpenetrating shape memory solid electrolyte. Thus, the double-network interpenetrating solid polymer electrolyte obtained in this invention not only exhibits high ionic conductivity and high strength, but also allows for uniform current distribution to effectively suppress lithium dendrite growth. Simultaneously, this solid polymer electrolyte also possesses shape memory intelligent carrier functionality, exhibits good compatibility with the cathode, and can meet the needs of the aerospace field for multifunctional intelligent materials.

[0029] According to some preferred embodiments, in step (1), the first functional monomer is glycidyl methacrylate; the polymer electrolyte monomer is poly(ethylene glycol) methyl ether methacrylate; the macromolecular initiator is tetrahydroxymethylpropane tris(2-bromoisobutyrate) or trihydroxymethylpropane tris(2-bromoisobutyrate); and the first organic solvent is toluene or ethylbenzene.

[0030] In this embodiment of the invention, the first functional monomer is preferably glycidyl methacrylate, which contains both epoxy groups and carbon-carbon double bonds and has a relatively short molecular chain. Reacting it with a macromolecular initiator and a polymer electrolyte monomer not only helps ensure that the formed polymer network has good mechanical properties, but also facilitates further reaction with other monomers to form a double-network interpenetrating structure. Simultaneously, using the aforementioned type of polymer electrolyte monomer not only imparts good ionic conductivity to the polymer network, but also, after further crosslinking with the second functional monomer and crosslinking agent, does not adversely affect the shape memory properties of the solid electrolyte, thus ensuring that the solid electrolyte possesses both good shape memory properties and ionic conductivity.

[0031] In the preparation of the ion-conducting polymer network colloid, to ensure good reaction efficiency, the first functional monomer, polymer electrolyte monomer, and macromolecular initiator were added to the first organic solvent under a nitrogen atmosphere. The solution was then degassed three times using a freeze pump thawing cycle, and subsequently placed in an oil bath at 70-80℃ for reaction, thereby preparing the ion-conducting polymer network colloid, the structural formula of which is as follows:

[0032] The wavy line does not represent any functional group, but only indicates the position where the carbon-carbon double bond is opened and combined with the Br-containing alkyl group. R1 is any alkyl group. The specific values ​​of x and y are not particularly limited and can be adjusted by adjusting the ratio of the first functional monomer and the polymer electrolyte monomer.

[0033] Meanwhile, in order to remove impurities from the ionic conductivity polymer network colloid, after the reaction is completed, the reaction solution is diluted with tetrahydrofuran and then filtered in a neutral alumina column to remove copper salts. The filtered product is then precipitated twice with excess diethyl ether. After filtration and vacuum drying, high-purity ionic conductivity polymer network colloid can be obtained.

[0034] It should be noted that, in order to ensure that the solid electrolyte has a suitable crosslinking density, the polymer electrolyte monomer (poly(ethylene glycol) methyl ether methacrylate) in this embodiment of the invention has the following structural formula:

[0035] n is the repeating unit, with a value ranging from 2 to 500.

[0036] According to some preferred embodiments, the second functional monomer is bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, epoxy phenolic resin, or bisphenol S diglycidyl ether; the crosslinking agent is polyetheramine, polyetherdiamine, or polyethertriamine; the electrolyte lithium salt is lithium bis(trifluoromethanesulfonyl)imide, lithium bis(fluorosulfonyl)imide, lithium difluorooxalateborate, or lithium dioxalateborate; and the second organic solvent is acetonitrile solution.

[0037] In this embodiment of the invention, when the above-mentioned second functional monomer, crosslinking agent, and electrolyte lithium salt are mixed with an ionicly conductive polymer network colloid for reaction, the second functional monomer can react with the above-mentioned crosslinking agent first, thereby forming a shape memory polymer network with shape memory properties and good strength, the structure of which is as follows:

[0038] The wavy lines do not represent any functional groups, but only indicate the bonding positions containing amino and epoxy groups;

[0039] Subsequently, the shape memory polymer network can undergo further polymerization with the ion-conductivity polymer network colloid, thereby forming a solid electrolyte with interpenetrating cross-linked structure of both shape memory polymer network and ion-conductivity polymer network (e.g., Figure 1 (As shown); This interpenetrating cross-linked solid polymer electrolyte not only exhibits high ionic conductivity, allowing for uniform current distribution to effectively suppress lithium dendrite growth and enabling lithium-ion batteries to exhibit excellent cycle stability, but also possesses excellent mechanical strength, which can improve the safety performance of lithium batteries. In addition, it also has the function of shape memory as a smart carrier, has good compatibility with the positive electrode, and is easy to process.

[0040] It should be noted that the crosslinking agent in the embodiments of the present invention is preferably polyetheramine, and the structural formula of polyetheramine is as follows:

[0041] n is a repeating unit with a value of 9-34; using a crosslinking agent with the above molecular weight to react with the second functional monomer is beneficial to ensuring good mechanical properties of the solid electrolyte.

[0042] According to some preferred embodiments, in step (1), during the preparation of the ion-conducting polymer network colloid, the content of the first functional monomer is 1-10% by weight (e.g., 1%, 2%, 3%, 5%, 8%, or 10%), the content of the polymer electrolyte monomer is 60-90% (e.g., 60%, 70%, 80%, or 90%), the content of the macromolecular initiator is 0.1-2% (e.g., 0.1%, 0.5%, 1%, 1.5%, or 2%), and the content of the first organic solvent is 2-15% (e.g., 2%, 5%, 8%, 10%, 12%, or 15%).

[0043] In this embodiment of the invention, by further rationally controlling the content of each reactant during the preparation of the ionic conductive polymer network colloid, it is beneficial to obtain an ionic conductive polymer network structure with good ionic conductivity, good strength, and a relatively stable structure. Simultaneously, the values ​​of x and y in the ionic conductive polymer network structure can be adjusted by adjusting the amounts of the first functional monomer and the polymer electrolyte monomer according to the actual requirements for ionic conductivity and structural strength, thereby adjusting the ionic conductivity and structural strength of the network structure. However, if the content of the first functional monomer is too high, it is not conducive to ensuring good ionic conductivity of the polymer network structure; if the content of the polymer electrolyte monomer is too high, the structure of the prepared solid electrolyte will be too soft, which is not conducive to ensuring good mechanical strength.

[0044] According to some preferred embodiments, in step (2), the mass ratio of the ion-conducting polymer network colloid and the second functional monomer is 1:(1-3) (e.g., 1:1, 1:2 or 1:3); the content of the crosslinking agent is 20-25% of the total amount of the ion-conducting polymer network colloid and the second functional monomer (e.g., 20%, 21%, 22%, 23%, 24% or 25%); in the preparation of the dual-network interpenetrating shape memory solid electrolyte, the content of the electrolyte lithium salt is 0.5-1% by weight (e.g., 0.5%, 0.8% or 1%), and the content of the second organic solvent is 10-20% (e.g., 10%, 15% or 20%).

[0045] In this embodiment of the invention, by controlling the content of ionic conductivity network colloid, second functional monomer and crosslinking agent, it is beneficial to prepare a solid electrolyte with good shape memory properties, ionic conductivity properties and good mechanical strength. If the content of ionic conductivity polymer network colloid is too small, the conductivity of the solid electrolyte will decrease. However, if the content of ionic conductivity polymer network colloid is too large, the ratio of ionic conductivity polymer network and shape memory polymer network will be unbalanced, which is not conducive to ensuring good shape memory properties of the solid electrolyte.

[0046] It should be noted that, in this embodiment of the invention, in order to ensure good ionic conductivity of the solid electrolyte, a lithium salt with a concentration of 1 mol / L is used to react with the above reactants.

[0047] According to some preferred embodiments, step (1), before the crosslinking reaction, further includes the step of adding a catalytic monomer to the reaction system; wherein the catalytic monomer includes 1,1,4,7,10,10-hexamethyltriethylenetetramine and copper bromide. The content of the catalytic monomer is 0.2-4% by weight (e.g., 0.2%, 0.5%, 0.8%, 1%, 2%, 3%, or 4%).

[0048] In this embodiment of the invention, by adding an appropriate amount of the above-mentioned catalytic monomers to the reaction system, it is beneficial to promote the occurrence of the reaction and increase the reaction efficiency; the preferred mass ratio of the two catalytic monomers is 1:1.

[0049] According to some preferred embodiments, in step (1), the reaction temperature is 70-80°C (e.g., 70°C, 72°C, 75°C, 78°C or 80°C), and the time is 2-6h (e.g., 2h, 3h, 5h or 6h); in step (2), the crosslinking temperature is 15-25°C (e.g., 15°C, 18°C, 20°C, 22°C or 25°C), and the time is 10-12h (e.g., 10h, 11h or 12h).

[0050] In this embodiment of the invention, after the reaction is complete, the reacted liquid can be poured into a mold coated with polytetrafluoroethylene and further heated at 80°C for 12-48 hours to ensure a complete reaction. After demolding, it is dried at 70-90°C for 12-48 hours to obtain the above-mentioned double-network interpenetrating shape memory solid electrolyte.

[0051] This invention also provides a shape memory solid electrolyte with interpenetrating dual networks, prepared using any of the above-described preparation methods.

[0052] This invention also provides an application of the shape memory solid electrolyte with dual-network interpenetration as described in any of the above embodiments in lithium batteries.

[0053] The solid electrolyte prepared in the embodiments of the present invention has good ionic conductivity and mechanical strength, as well as good shape memory properties. It can undergo shape transformation through external stimuli (such as thermal stimulation). The glass transition temperature of the solid electrolyte material in the embodiments of the present invention is about 60°C. It has great application potential in smart materials and devices. Applying it to lithium batteries can solve the problems of poor safety and low energy density of existing solid batteries.

[0054] To more clearly illustrate the technical solution and advantages of the present invention, the following describes in detail a shape memory solid electrolyte with dual interpenetrating networks and its preparation method through several embodiments.

[0055] Example 1:

[0056] (1) Add 5 wt% of the first functional monomer (glycidyl methacrylate), 75 wt% of the polymer electrolyte monomer (poly(ethylene glycol) methyl ether methacrylate), 0.5 wt% of the macromolecular initiator (tetrahydroxymethylpropane tri(2-bromoisobutyrate)), and 1 wt% of the catalytic monomer (1,1,4,7,10,10-hexamethyltriethylenetetramine and copper bromide in a mass ratio of 1:1) to a Schlenk flask containing 8 wt% anhydrous toluene and stir to mix well.

[0057] The solution was degassed three times using a freeze-pump-thaw cycle. The flask was then immersed in an oil bath preheated to 75°C. After reacting for 4 hours, the reaction was quenched in liquid nitrogen. The resulting solution was diluted with 300 mL of tetrahydrofuran, passed through a neutral alumina column to remove copper salts, and precipitated twice with 2 L of diethyl ether. After filtration and vacuum drying at 45°C, an ion-conducting polymer network colloid was obtained.

[0058] (2) The ionic conductivity polymer network colloid and the second functional monomer (bisphenol A diglycidyl ether) with a mass ratio of 1:1 were mixed, and a crosslinking agent (polyetheramine), an electrolyte lithium salt (lithium bis(trifluoromethanesulfonyl)imide) and 10 wt% of a second organic solvent (acetonitrile solution) were added. The mixture was stirred and mixed at 25 °C for 12 h to obtain a reaction precursor solution. The reaction precursor solution was poured into a mold coated with polytetrafluoroethylene, heated to 80 °C and reacted for 4 h. After cooling and demolding, the mixture was further vacuum dried at 80 °C for 24 h to obtain a shape memory solid electrolyte with a double network interpenetrating structure. The amount of crosslinking agent added was 20% of the total amount of the ionic conductivity polymer network colloid and the second functional monomer, and the amount of electrolyte lithium salt added was 1 wt%.

[0059] Example 2:

[0060] Example 2 is basically the same as Example 1, except that: in step (1), the content of the first functional monomer (glycidyl methacrylate) is 10 wt% and the content of the polymer electrolyte monomer (poly(ethylene glycol) methyl ether methacrylate) is 60 wt%; and in step (2), the mass ratio of the ion-conducting polymer network colloid and the second functional monomer is 1:2.

[0061] Example 3:

[0062] Example 3 is basically the same as Example 1, except that: in step (1), the content of the first functional monomer (glycidyl methacrylate) is 8 wt% and the content of the polymer electrolyte monomer (poly(ethylene glycol) methyl ether methacrylate) is 70 wt%; and in step (2), the mass ratio of the ion-conducting polymer network colloid and the second functional monomer is 1:3.

[0063] Example 4:

[0064] Example 4 is basically the same as Example 1, except that in step (2), the mass ratio of the ion-conducting polymer network colloid and the second functional monomer is 1:2.

[0065] Example 5:

[0066] Example 5 is basically the same as Example 1, except that in step (2), the mass ratio of the ion-conducting polymer network colloid and the second functional monomer is 1:3.

[0067] Example 6:

[0068] Example 6 is basically the same as Example 1, except that in step (1), the content of the first functional monomer is 15 wt%.

[0069] Example 7:

[0070] Example 7 is basically the same as Example 1, except that in step (1), the content of the polymer electrolyte monomer is 95 wt%.

[0071] Example 8:

[0072] Example 8 is basically the same as Example 1, except that in step (1), the content of the macromolecular initiator is 5 wt%.

[0073] Example 9:

[0074] Example 9 is basically the same as Example 1, except that in step (2), the mass ratio of the ion-conducting polymer network colloid and the second functional monomer is 1:4.

[0075] Comparative Example 1:

[0076] (1) Add 5 wt% of the first functional monomer (glycidyl methacrylate), 75 wt% of the polymer electrolyte monomer (poly(ethylene glycol) methyl ether methacrylate), 0.5 wt% of the macromolecular initiator (tetrahydroxymethylpropane tri(2-bromoisobutyrate)), and 1 wt% of the catalytic monomer (1,1,4,7,10,10-hexamethyltriethylenetetramine and copper bromide in a mass ratio of 1:1) to a Schlenk flask containing 8 wt% anhydrous toluene and stir to mix well.

[0077] The solution was degassed three times using a freeze-pump-thaw cycle. The flask was then immersed in an oil bath preheated to 75°C. After reacting for 4 hours, the reaction was quenched in liquid nitrogen. The resulting solution was diluted with 300 mL of tetrahydrofuran, passed through a neutral alumina column to remove copper salts, and precipitated twice with excess 2 L of diethyl ether. After filtration and vacuum drying at 45°C, an ion-conducting polymer network colloid was obtained.

[0078] (2) Add crosslinking agent (polyetheramine) and electrolyte lithium salt (lithium bis(trifluoromethanesulfonyl)imide) to the ion-conducting polymer network colloid and stir and mix at 25°C for 12 h to obtain a reaction precursor solution. Pour the reaction precursor solution into a mold coated with polytetrafluoroethylene, heat to 80°C and continue to react for 4 h. After cooling and demolding, further vacuum dry at 80°C for 24 h to obtain a solid electrolyte. The amount of crosslinking agent added is 20% of the ion-conducting polymer network colloid and the amount of electrolyte lithium salt added is 1 wt%.

[0079] The solid electrolytes (hereinafter referred to as samples) prepared in Examples 1 to 9 and Comparative Example 1 were subjected to performance tests, and the test results are shown in Table 1.

[0080] Young's modulus test standard: ASTM D638: Standard test method for tensile properties of plastics;

[0081] Specific testing method: Tensile specimens are tested using a universal testing machine (UTM), and the applied stress and strain are measured. Young's modulus is the slope of the linear portion of the stress-strain curve.

[0082] Electrochemical window testing: This is performed using linear sweep voltammetry. Specifically, the sample is placed in the battery, typically using a three-electrode system: a working electrode (e.g., Pt or glassy carbon electrode), a reference electrode (e.g., Ag / AgCl), and a counter electrode (e.g., platinum sheet or graphite). The potential is gradually increased, starting from a stable state, and the current is recorded. The obvious current rise points in the voltage-current curve are analyzed, which represent the voltage at which the electrolyte begins to decompose. These points indicate the upper and lower limits of the electrochemical window.

[0083] Ionic conductivity test: Test procedure: Place the sample to be tested in a two-electrode fixture, usually using stainless steel, electroplated platinum or other inert electrodes. Using an electrochemical impedance spectroscopy instrument, apply an alternating current signal ranging from a few hertz to a few megahertz, measure and record the phase difference between voltage and current, and obtain the impedance spectrum (Nyquist diagram) of the sample. Through equivalent circuit fitting analysis, determine the resistance of the sample, and calculate the ionic conductivity by combining the thickness and surface area of ​​the sample.

[0084] Shape memory performance test: The above sample is prepared into a thin film, and then a temporary shape is fixed at 10-20℃ above Tg (response temperature), and fixed at a temperature below Tg (e.g., room temperature 20-30℃). The fixed sample is then heated to a temperature above Tg. The shape memory performance of the sample is evaluated based on the shape memory recovery rate and fixation rate. Evaluation criteria: above 85% (good), above 95% (excellent), below 50% does not have shape memory performance.

[0085] Table 1

[0086]

[0087] From Table 1 and Figure 1 As can be seen from the above, compared with the comparative example, the solid electrolyte prepared in the embodiment of the present invention is formed by interpenetrating cross-linking of shape memory polymer network and ion conductivity polymer network. This solid electrolyte not only has high ion conductivity, which can effectively suppress lithium dendrite growth, but also has good mechanical strength and high voltage resistance. At the same time, it also has good shape memory performance, which can undergo shape transformation by external stimulation. It has great application potential in smart materials and devices.

[0088] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; 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 of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a shape memory solid electrolyte with interpenetrating dual networks, characterized in that, The preparation method includes the following steps: (1) The first functional monomer, the polymer electrolyte monomer and the macromolecular initiator are added to the first organic solvent and mixed and reacted to obtain an ion-conducting polymer network colloid; wherein, the first functional monomer contains an epoxy group and a carbon-carbon double bond; the first functional monomer is glycidyl methacrylate; the polymer electrolyte monomer is poly(ethylene glycol) methyl ether methacrylate; the macromolecular initiator is tetrahydroxymethylpropane tris(2-bromoisobutyrate) or trihydroxymethylpropane tris(2-bromoisobutyrate); the first organic solvent is toluene or ethylbenzene; (2) The ion-conducting polymer network colloid, the second functional monomer, the crosslinking agent and the electrolyte lithium salt are added to the second organic solvent and mixed and crosslinked to obtain the shape memory solid electrolyte with the double network interpenetration; wherein, the second functional monomer contains an epoxy group; the second functional monomer is bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, epoxy phenolic resin or bisphenol S diglycidyl ether; the crosslinking agent is polyetheramine, polyether diamine or polyether triamine.

2. The preparation method according to claim 1, characterized in that, The electrolyte lithium salt is lithium bis(trifluoromethanesulfonyl)imide, lithium bis(fluorosulfonyl)imide, lithium difluorooxalateborate, or lithium dioxalateborate; the second organic solvent is an acetonitrile solution.

3. The preparation method according to claim 1, characterized in that, In step (1), during the preparation of the ion-conducting polymer network colloid, the content of the first functional monomer is 1-10% by weight, the content of the polymer electrolyte monomer is 60-90%, the content of the macromolecular initiator is 0.1-2%, and the content of the first organic solvent is 2-15%.

4. The preparation method according to claim 1, characterized in that, In step (2), the mass ratio of the ion-conducting polymer network colloid to the second functional monomer is 1:(1-3); the content of the crosslinking agent is 20-25% of the total amount of the ion-conducting polymer network colloid and the second functional monomer; and / or In the preparation of the dual-network interpenetrating shape memory solid electrolyte, the content of the electrolyte lithium salt is 0.5-1% by weight, and the content of the second organic solvent is 10-20%.

5. The preparation method according to claim 1, characterized in that, In step (2), before the crosslinking reaction, a step of adding a catalytic monomer to the reaction system is also included; wherein the catalytic monomer includes 1,1,4,7,10,10-hexamethyltriethylenetetramine and copper bromide.

6. The preparation method according to claim 5, characterized in that, The content of the catalytic monomer is 0.2-4% by weight.

7. The preparation method according to claim 1, wherein in step (1), the reaction temperature is 70-80℃ and the time is 2-6h; and / or In step (2), the crosslinking temperature is 15-25℃ and the time is 10-12h.

8. A shape memory solid electrolyte with dual interpenetrating networks, characterized in that, It is prepared by any one of the preparation methods according to claims 1 to 7.

9. The application of the shape memory solid electrolyte with dual interpenetrating networks prepared by any one of claims 1 to 7, or the shape memory solid electrolyte with dual interpenetrating networks according to claim 8, in lithium batteries.

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