Self-healing polymer electrolyte for energy storage frequency modulation and preparation method thereof

Abstract

The present disclosure provides a self-healing polymer electrolyte for energy storage frequency modulation and a preparation method thereof. The preparation method comprises modifying Li 6.4 La3Zr 1.4 Ta 0.6 O 12 nanocrystal surface modification, separation, washing, drying to obtain a thiol-modified Li 6.4 La3Zr 1.4 Ta 0.6 O 12 functional inorganic phase; a linear prepolymer containing a dynamic furan acylhydrazone bond is constructed by using polyethylene glycol diamine and 2,5-diformylfuran as raw materials, an electrolyte salt is added to the linear prepolymer, and a precursor prepolymer solution containing a dynamic bond is obtained after dissolution; the thiol-modified Li 6.4 La3Zr 1.4 Ta 0.6 O 12 functional inorganic phase is compounded with the precursor prepolymer solution containing a dynamic bond, a crosslinking agent and a photoinitiator are added, and a gel-like composite film body is obtained under ultraviolet-thermal dual initiation; gradient vacuum drying is performed to obtain a polymer electrolyte membrane.

Description

Technical Field

[0001] This disclosure belongs to the field of energy storage frequency regulation technology, specifically relating to a method for preparing a self-healing polymer electrolyte for energy storage frequency regulation. Background Technology

[0002] Energy storage frequency regulation is a core component of the safe and stable operation of power systems, placing stringent requirements on energy storage devices for high energy density, continuous and stable operation, safety, reliability, and resistance to mechanical damage. Lithium metal batteries, due to their ultra-high energy density potential, have become a core candidate system for next-generation energy storage devices in the field of energy storage frequency regulation. However, their traditional liquid electrolytes pose safety hazards such as leakage and explosion, making them unsuitable for the large-scale, long-term application requirements of energy storage frequency regulation scenarios.

[0003] Polymer electrolytes, as an ideal alternative to liquid electrolytes, offer advantages such as strong structural adaptability and no leakage risk in energy storage and frequency regulation lithium metal batteries. However, they still face key bottlenecks, including inorganic-organic phase separation, lack of self-healing ability, low room temperature ionic conductivity, insufficient mechanical strength, and poor resistance to lithium dendrite formation. Phase separation leads to rapid performance degradation of the electrolyte, failing to meet the long-cycle requirements of energy storage and frequency regulation. The lack of self-healing ability causes the electrolyte to fail directly after mechanical damage, affecting the continuous operation of energy storage devices. Low ionic conductivity restricts the battery's charge and discharge response speed, making it difficult to match the rapid power regulation requirements of frequency regulation scenarios. Insufficient mechanical strength and resistance to lithium dendrite formation can easily lead to internal short circuits in the battery, posing safety risks.

[0004] Therefore, in view of the limitations of the traditional "single organic phase + static crosslinking", which leads to the technical problems of electrolyte brittleness, low ion transport efficiency and irreparable damage, it is necessary to propose a new process to simultaneously improve the ionic conductivity, mechanical strength, thermal stability and self-healing performance of polymer electrolytes. Summary of the Invention

[0005] This disclosure aims to at least address one of the problems of single organic phase and static crosslinking technology in the prior art, and to provide a self-healing polymer electrolyte for energy storage frequency modulation and its preparation method.

[0006] One aspect of this disclosure provides a method for preparing a self-healing polymer electrolyte for energy storage frequency modulation, comprising: S1. Under an inert atmosphere and with the aid of a catalyst, the reaction of Li with 3-mercaptopropyltriethoxysilane... 6.4 La3Zr 1.4 Ta 0.6 O 12 Surface modification of nanocrystals was performed by grafting thiol groups via silanol condensation reaction. After separation, washing, and drying, thiol-modified Li was obtained. 6.4 La3Zr 1.4Ta 0.6 O 12 Functionalized inorganic phases; S2. Under an inert atmosphere, using polyethylene glycol diamine and 2,5-dicarboxyfuran as raw materials, a linear prepolymer containing dynamic furanoylhydrazone bonds is constructed through nucleophilic addition-elimination reaction of amino and aldehyde groups. An electrolyte salt is added to the linear prepolymer, and after dissolution, a precursor prepolymer solution containing dynamic bonds is obtained. S3, the thiol-modified Li 6.4 La3Zr 1.4 Ta 0.6 O 12 The functionalized inorganic phase is combined with the precursor prepolymer liquid containing dynamic bonds, and a crosslinking agent and a photoinitiator are added. Under UV-thermal dual initiation conditions, a three-dimensional interpenetrating network structure is constructed by crosslinking the inorganic and organic phases through mercapto-olefin click reaction and furanoylhydrazone bond strengthening reaction, resulting in a gel-like composite film. S4. The gel-like composite membrane is subjected to gradient heating and vacuum drying to obtain a functionalized inorganic phase-enhanced dynamic cross-linked polymer electrolyte membrane.

[0007] Optionally, the 3-mercaptopropyltriethoxysilane and the Li 6.4 La3Zr 1.4 Ta 0.6 O 12 The mass ratio of nanocrystals is (0.3~0.7):1; The Li 6.4 La3Zr 1.4 Ta 0.6 O 12 Nanocrystals are pure cubic phases with a particle size ranging from 40 to 80 nm and a bulk ionic conductivity at room temperature ≥ 2 × 10⁻⁶. -4 S / cm; The surface modification temperature is 65-75℃, and the time is 3.5-4.5h.

[0008] Optionally, in the case of the mercapto-modified Li 6.4 La3Zr 1.4 Ta 0.6 O 12 When the functionalized inorganic phase is compounded with the precursor prepolymer containing dynamic bonds, the thiol-modified Li 6.4 La3Zr 1.4 Ta 0.6 O 12 The mass ratio of the added functionalized inorganic phase to polyethylene glycol diamine is (0.5~3.0):8.

[0009] Optionally, the electrolyte salt is lithium bis(trifluoromethanesulfonyl)imide, and the mass ratio of the electrolyte salt to polyethylene glycol diamine is (1.5~2.0):1.

[0010] Optionally, the crosslinking agent is trimethylolpropane triacrylate or pentaerythritol triacrylate; the mass ratio of the crosslinking agent to the polyethylene glycol diamine is (0.2~0.3):1.

[0011] Optionally, the ultraviolet-thermal dual initiation conditions include: ultraviolet light wavelength of 365nm, irradiation time of 20~40min; thermal initiation temperature of 50~70℃, and heat preservation time of 1~3h.

[0012] Optionally, the gradient temperature vacuum drying includes: first vacuum drying at 40~60℃ for 5~7h, and then vacuum drying at 80~100℃ for 10~14h.

[0013] Optionally, the polymer electrolyte membrane has an interpenetrating network of inorganic backbone and organic segments, as well as furanylhydrazone coordination channels in the organic phase and Li 6.4 La3Zr 1.4 Ta 0.6 O 12 Bulk fast ion channels, Li 6.4 La3Zr 1.4 Ta 0.6 O 12 Triple ion transport pathways in surface hydrophilic channels.

[0014] In another aspect of this disclosure, a self-healing polymer electrolyte for energy storage frequency regulation is provided, wherein the self-healing polymer electrolyte is prepared by the above-described preparation method.

[0015] This disclosure proposes a core technical solution of "constructing a triple ion transport channel in an inorganic phase of a fast ion conductor + achieving efficient self-repair through dynamic cross-linking of furanoylhydrazone". By improving the compatibility of the inorganic-organic two phases through chemical bonding, a triple ion transport path of organic-inorganic bulk phase-inorganic surface is constructed, which simultaneously improves the ion conductivity, lithium-ion transference number, mechanical strength, thermal stability and self-repair performance of the polymer electrolyte, making it perfectly suited to the full-dimensional performance requirements of lithium metal batteries in energy storage and frequency regulation scenarios. Attached Figure Description

[0016] Figure 1 This is a flowchart illustrating a method for preparing a self-healing polymer electrolyte for energy storage frequency modulation according to a specific embodiment of this disclosure. Figure 2 The high and low temperature performance results of Examples 1, 4, Comparative Example 1 and Comparative Example 2 of this disclosure; Figure 3 The impedance results are for Embodiment 4 and Comparative Example 1 of this disclosure. Detailed Implementation

[0017] To enable those skilled in the art to better understand the technical solutions of this disclosure, the disclosure will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain this disclosure and represent a part of the embodiments of this disclosure, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without creative effort are within the protection scope of this disclosure.

[0018] like Figure 1 As shown, the preparation method S100 of the self-healing polymer electrolyte for energy storage frequency modulation provided in this disclosure specifically includes the following steps S110~S140: S110, mercaptosilane modified Li 6.4 La3Zr 1.4 Ta 0.6 O 12 Nanocrystals, constructing functionalized inorganic phases: using pure cubic phase Li 6.4 La3Zr 1.4 Ta 0.6 O 12 Using LLZTO nanocrystals as a substrate, the surface of LLZTO nanocrystals was modified by 3-mercaptopropyltriethoxysilane (MPTES) under an inert atmosphere and with the aid of a catalyst. Thiol groups were grafted using a silanol condensation reaction. After separation, washing and drying, a thiol-modified LLZTO (SH-LLZTO) functionalized inorganic phase was obtained.

[0019] Specifically, in step S110, LLZTO nanocrystals are first dissolved in anhydrous ethanol and ultrasonically dispersed to form a homogeneous emulsion. High-purity nitrogen is then introduced to purge air from the system and maintain an inert atmosphere. Under oil bath conditions at 65-75℃, 3-mercaptopropyltriethoxysilane is added. After the addition is complete, concentrated hydrochloric acid is added as a catalyst, and the mixture is stirred at a constant temperature for 3.5-4.5 hours. After the reaction is complete, the product is centrifuged at 7500-8500 r / min for 5-15 minutes, the precipitate is collected, washed three times with anhydrous ethanol, and then vacuum dried at 75-85℃ for 5-7 hours to obtain the SH-LLZTO functionalized inorganic phase, which is then sealed for later use.

[0020] In some preferred embodiments, the mass ratio of 3-mercaptopropyltriethoxysilane to LLZTO nanocrystals is (0.3~0.7):1.

[0021] In some preferred embodiments, the LLZTO nanocrystals are pure cubic phase with a particle size ranging from 40 to 80 nm and a bulk ionic conductivity at room temperature ≥ 2 × 10⁻⁶.-4 S / cm. This material belongs to rigid ceramic materials, and its Young's modulus is much higher than that of polymers. Uniformly dispersing it in a polymer network can greatly improve the mechanical strength, modulus, and toughness of the composite film. Meanwhile, the LLZTO surface is rich in La... 3+ Zr Ta 5+ The isotope is a strong Lewis acid, which is effective against anions in the electrolyte (such as TFSI). - LLZTO exhibits strong adsorption and anchoring properties, which effectively limit anion migration, thereby significantly increasing the lithium-ion transference number. Furthermore, the addition of LLZTO can disrupt the crystalline regions of polymer matrices such as PEO, increasing the content of amorphous regions and enhancing the mobility of polymer chains, indirectly improving the ionic conductivity of the polymer phase. In addition, the use of a pure cubic phase avoids the presence of low-conductivity tetragonal or impurity phases, ensuring that the inorganic phase itself provides optimal ion transport capabilities. Moreover, the nanocrystals within the aforementioned particle size range provide more interfacial regions, facilitating interaction and ion exchange with the polymer matrix.

[0022] It is important to note that LLZTO is mainly bonded to the polymer matrix through physical adsorption or van der Waals forces. This interfacial bonding is weak and prone to debonding under high stress or long-term cycling. To address this, this embodiment modifies the LLZTO. The silanol (-Si-OH) formed by the hydrolysis of silanoxy groups (-Si(OCH2CH3)3) in MPTES undergoes a condensation reaction with the hydroxyl groups (-OH) on the LLZTO surface, forming a strong Si-OM (M is La, Zr, Ta, etc.) covalent bond. This firmly grafts the MPTES molecules onto the LLZTO surface. The other end of the grafted MPTES has a thiol group (-SH). Through the subsequent thiol-alkene click reaction, this -SH group can rapidly and efficiently covalently bond with unsaturated bonds (such as alkene bonds) in the organic polymer network. In this way, LLZTO nanoparticles are chemically introduced into the three-dimensional polymer network, greatly improving the interfacial bonding strength and reducing the organic-inorganic interfacial impedance. In other words, LLZTO not only provides ion conduction and mechanical reinforcement, but its surface Lewis acid sites can also interact with dynamic bonds or polymer chains to further optimize ion transport pathways and self-healing behavior.

[0023] The functionalized LLZTO (with -SH) in this step serves as the active component, directly participating in the subsequent thiol-alkene click chemistry reaction and forming covalent bonds with the organic polymer network. In other words, the compatibility between the inorganic phase and the subsequent organic phase is improved through chemical bonding, providing a structural basis for the long-term stability of the subsequent composite system.

[0024] S120, amino-aldehyde prepolymer, constructing a precursor containing dynamic bonds: Under an inert atmosphere, using polyethylene glycol diamine (PEGDA) and 2,5-dicarboxyfuran as raw materials, a linear prepolymer containing dynamic furanoylhydrazone bonds is constructed through nucleophilic addition-elimination reaction of amino and aldehyde groups. An electrolyte salt is added to the prepolymer system, and after stirring and dissolving, a homogeneous and transparent precursor prepolymer solution containing dynamic bonds is obtained.

[0025] Specifically, in step S120, polyethylene glycol diamine and N,N-dimethylformamide (DMF) are first completely dissolved under magnetic stirring at 350-450 r / min, then cooled to 20-30℃, and a DMF solution of 2,5-dicarboxyfuran is added dropwise at a rate of 0.5-1.5 mL / min. After the addition is complete, the mixture is stirred for 1-3 h. Subsequently, an electrolyte salt is added to the system, and stirring is continued for 0.5-1.5 h until completely dissolved, resulting in a homogeneous and transparent prepolymer solution.

[0026] In some preferred embodiments, the molar ratio of polyethylene glycol diamine to 2,5-dicarboxyfuran is 1:(1~1.2).

[0027] In some preferred embodiments, the molecular weight of PEGDA is 1000~2000. The PEGDA chain segment length in this molecular weight range is moderate, and the ratio with dynamic furanylhydrazone bonds and mercapto-olefin crosslinking agents is easier to coordinate, so as to form a moderately dense three-dimensional network containing dynamic bonds, which takes into account both ion conduction performance and mechanical strength.

[0028] In some preferred embodiments, the electrolyte salt is lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), and the mass ratio of the electrolyte salt to polyethylene glycol diamine is (1.5~2.0):1.

[0029] The dynamic furanoylhydrazone bond formed in this step provides core support for the self-healing performance of the electrolyte. The oxygen atom on the furan ring can additionally coordinate with lithium ions, enriching the ion transport sites. LiTFSI provides the lithium ion transport source for the system.

[0030] S130, Inorganic phase composite and thiol-double bond crosslinking to construct a three-dimensional interpenetrating network: The SH-LLZTO functionalized inorganic phase is composited with the precursor prepolymer liquid containing dynamic bonds, and a crosslinking agent and a photoinitiator are added. Under UV-thermal dual initiation conditions, covalent crosslinking of the inorganic and organic phases is achieved through thiol-alkene click reaction and furanoylhydrazone bond strengthening reaction to construct a dense three-dimensional interpenetrating network structure and obtain a gel-like composite film.

[0031] Specifically, in step S130, SH-LLZTO is first added to the prepolymer solution and ultrasonically dispersed for 15-25 minutes. Then, crosslinking agent and photoinitiator are added, and the mixture is magnetically stirred for 25-35 minutes until the system is homogeneous. The mixture is then transferred to a polytetrafluoroethylene mold and placed in a vacuum drying oven at 35-45℃ for 25-35 minutes to remove air bubbles. The mold is then irradiated with 365nm ultraviolet light for 20-40 minutes to complete photoinitiated crosslinking. Afterward, the mold is transferred to an oven and heated to 50-70℃ for 1-3 hours to complete thermal initiation strengthening. After cooling to room temperature, a gel-like composite film is obtained.

[0032] In some preferred embodiments, the mercapto-modified Li 6.4 La3Zr 1.4 Ta 0.6 O 12 When the functionalized inorganic phase is compounded with the precursor prepolymer containing dynamic bonds, the thiol-modified Li 6.4 La3Zr 1.4 Ta 0.6 O 12 The mass ratio of the added functionalized inorganic phase to polyethylene glycol diamine is (0.5~3.0):8.

[0033] It should be noted that, based on 8.0 g of polyethylene glycol diamine, the amount of the SH-LLZTO functionalized inorganic phase added to the polymer electrolyte membrane is 0.5 to 3.0 g, for example, more preferably 1.5 to 2.5 g.

[0034] In some preferred embodiments, the crosslinking agent is trimethylolpropane triacrylate (TMPTA) or pentaerythritol triacrylate (PETA), and the mass ratio of the crosslinking agent to polyethylene glycol diamine is (0.2~0.3):1.

[0035] In some preferred embodiments, the photoinitiator is 2-hydroxy-2-methyl-1-phenyl-1-propanone, and the mass ratio of the photoinitiator to polyethylene glycol diamine is (0.01-0.02):1.

[0036] The UV-thermal dual-initiation mechanism employed in this step ensures a uniform and dense cross-linked structure. The surface-grafted -SH group is an active functional group for the thiol-alkene click reaction. Through the thiol-alkene click reaction, stable covalent bonds are formed between the inorganic nanoparticle surface and the organic polymer network, constructing an inorganic framework-organic segment interpenetrating network, eliminating the risk of inorganic-organic phase separation at the molecular level. Simultaneously, lithium ions can coordinate with furanoylhydrazone bonds, achieving leapfrog migration through reversible breaking and recombination of dynamic bonds. They can also migrate rapidly within the SH-LLZTO bulk NASICON framework and achieve rapid interfacial transport within the hydrophilic layer formed by abundant hydroxyl groups on the SH-LLZTO particle surface. Ultimately, a triple lithium ion transport channel is constructed, laying the core foundation for the high ion conductivity of the electrolyte.

[0037] S140. Gradient drying to optimize the overall performance of the electrolyte: The gel-like composite membrane is subjected to gradient heating and vacuum drying to obtain a functionalized inorganic phase-reinforced dynamic cross-linked polymer electrolyte membrane with high mechanical strength, high ion conductivity, high lithium ion transference number and self-healing activity.

[0038] Specifically, in step S140, the gradient temperature vacuum drying process involves first vacuum drying at 40–60°C for 5–7 hours, followed by vacuum drying at 80–100°C for 10–14 hours. This gradient temperature vacuum drying process thoroughly removes residual solvent from the composite membrane, while simultaneously promoting the dynamic recombination of furanoylhydrazone bonds, further optimizing the three-dimensional network structure. Combined with the rigid support and channel guiding effect of SH-LLZTO, this simultaneously improves the mechanical properties, ion conductivity, and cycling stability of the electrolyte. The final polymer electrolyte membrane has a thickness of 0.2–0.3 mm.

[0039] Addressing the core bottlenecks of existing technologies, this implementation method modifies LLZTO nanocrystals with MPTES by grafting thiol groups, and then achieves covalent bonding between the inorganic and organic phases through a thiol-olefin click reaction, constructing a stable inorganic framework-organic segment interpenetrating network, thus fundamentally solving the problem of inorganic-organic phase separation. A dynamic furanoylhydrazone bond is constructed by reacting polyethylene glycol diamine with 2,5-dicarboxyfuran. This bond can undergo reversible nucleophilic addition-elimination reactions under thermal or mechanical stimulation, exhibiting superior reversibility compared to traditional phenylcyclohydrazone bonds, enabling efficient room-temperature self-repair through the recombination of active groups after membrane damage. The innovatively constructed triple ion transport pathway significantly reduces the lithium-ion transport energy barrier, increasing the room-temperature ion conductivity to 10. -3With a strength on the order of S / cm and a lithium-ion transference number exceeding 0.6, LLZTO perfectly meets the rapid power regulation requirements of energy storage frequency regulation scenarios. LLZTO itself has a Young's modulus of up to 150 GPa. Its rigid framework and organic cross-linked network work together to increase the tensile strength of the membrane to over 4 MPa. The dense network physically blocks lithium dendrites, and the uniform lithium-ion flux reduces lithium dendrite nucleation sites, achieving simultaneous enhancement of mechanical strength and resistance to lithium dendrite formation. At the same time, the inorganic phase can significantly improve the thermal stability of the system, greatly increasing the electrolyte thermal decomposition temperature, meeting the application requirements of large-scale, long-term, and highly safe energy storage frequency regulation scenarios.

[0040] This invention innovatively constructs a three-dimensional interpenetrating structure of "thiol-olefin click stabilizing network" and "main chain furanoylhydrazone dynamic network", which can ensure strength and processability, while endowing it with self-healing and toughness.

[0041] Another aspect of this disclosure provides a self-healing polymer electrolyte for energy storage frequency modulation. The electrolyte is prepared by the above-described method and has an interpenetrating network of inorganic backbone and organic segments, as well as a triple ion transport pathway consisting of an organic phase furanoylhydrazone coordination channel, an LLZTO bulk fast ion channel, and an LLZTO surface hydrophilic channel. It combines high ion conductivity, high mechanical strength, high self-healing efficiency, and excellent cycle stability.

[0042] The preparation method of the polymer electrolyte membrane will be further explained below with reference to specific embodiments: Example 1 Step 1: Preparation of LLZTO nanocrystals modified with mercaptosilane: Take 10.0 g of pure cubic LLZTO nanocrystals with a particle size of 60 nm (room temperature bulk ionic conductivity 2.5 × 10⁻⁶). -4 The product (S / cm) was placed in a 500mL three-necked flask, and 200mL of anhydrous ethanol was added. The mixture was ultrasonically dispersed for 30min until a homogeneous emulsion was formed. High-purity nitrogen was then introduced for 30min to purge air and maintain a nitrogen atmosphere. The flask was placed in an oil bath and heated to 70℃. A magnetic stirring speed of 500r / min was set, and 5.0mL of 3-mercaptopropyltriethoxysilane (MPTES) was added dropwise. After the addition was complete, 0.5mL of concentrated hydrochloric acid was added as a catalyst, and the mixture was stirred at a constant temperature for 4h. After the reaction was complete, the product was centrifuged at 8000r / min for 10min, and the precipitate was collected. The precipitate was washed three times with anhydrous ethanol (50mL each time), and then dried in a vacuum drying oven at 80℃ for 6h to obtain a white powder, SH-LLZTO, which was sealed for later use.

[0043] Step 2: Preparation of prepolymer solution containing dynamic furanoylhydrazone bonds: High-purity nitrogen gas was bubbled into a 250 mL three-necked flask. 8.0 g of polyethylene glycol diamine (PEGDA, molecular weight 1000) and 120 mL of N,N-dimethylformamide (DMF) were added, and the mixture was magnetically stirred (400 rpm) until completely dissolved. The temperature was then lowered to 25 °C. 8.0 g of a DMF solution of 2,5-diformylfuran (concentration 0.2 g / mL) was slowly added dropwise at a rate of 1 mL / min. Slight turbidity gradually appeared during the addition process, and stirring was continued for 2 h. Subsequently, 15.0 g of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) was added, and the mixture was stirred for 1 h until completely dissolved, yielding a homogeneous and transparent prepolymer solution.

[0044] Step 3: Preparation of Inorganic Phase Composite and Crosslinked Membrane: 2.0 g of SH-LLZTO prepared in step one was added to the prepolymer solution and ultrasonically dispersed for 20 min. Then, 2.0 g of trimethylolpropane triacrylate (TMPTA) and 0.1 g of photoinitiator 2-hydroxy-2-methyl-1-phenyl-1-propanone were added, and the mixture was magnetically stirred for 30 min until homogeneous. The mixture was transferred to a polytetrafluoroethylene mold and placed in a vacuum drying oven at 40 °C for 30 min to remove air bubbles. UV-thermal dual-initiation crosslinking was performed: first, the mold was irradiated with 365 nm UV light for 30 min; then, the mold was transferred to an oven, heated to 60 °C and held for 2 h, and cooled to room temperature to obtain a gel-like composite film.

[0045] Step 4: Gradient drying. The gel composite membrane was placed in a vacuum drying oven and dried at 50°C for 6 hours. Then, the temperature was raised to 90°C and dried for 12 hours. It was then naturally cooled to room temperature to obtain a functionalized inorganic phase-reinforced dynamic crosslinked polymer electrolyte membrane with a thickness of 0.25 mm.

[0046] Example 2 The difference from Example 1 is that the LLZTO nanocrystals in step one have a particle size of 40 nm, while the amounts of other raw materials and reaction conditions are the same as in Example 1, and a polymer electrolyte membrane is prepared.

[0047] Example 3 The difference from Example 1 is that the amount of MPTES used in step one is 3.0 mL, while the amounts of other raw materials and reaction conditions are the same as in Example 1, and a polymer electrolyte membrane is prepared.

[0048] Example 4 The difference from Example 1 is that the amount of MPTES used in step one is 7.0 mL, while the amounts of other raw materials and reaction conditions are the same as in Example 1, and a polymer electrolyte membrane is prepared.

[0049] Example 5 The difference from Example 1 is that the molecular weight of PEGDA in step two is 2000, while the amount of other raw materials and reaction conditions are the same as in Example 1, and a polymer electrolyte membrane is prepared.

[0050] Example 6 The difference from Example 1 is that the amount of SH-LLZTO added in step 3 is 0.5g, while the amount of other raw materials and reaction conditions are the same as in Example 1, and a polymer electrolyte membrane is prepared.

[0051] Example 7 The difference from Example 1 is that the amount of SH-LLZTO added in step 3 is 3.0g, while the amount of other raw materials and reaction conditions are the same as in Example 1, and a polymer electrolyte membrane is prepared.

[0052] Example 8 The difference from Example 1 is that the crosslinking agent in step three is replaced with pentaerythritol triacrylate (PETA), and the amount is still 2.0g. The amounts of other raw materials and reaction conditions are the same as in Example 1, and a polymer electrolyte membrane is prepared.

[0053] Comparative Example 1 Step 1 in Example 1 is omitted, and steps 2 to 4 are performed directly. SH-LLZTO is not added in step 3. The amounts of other raw materials and reaction conditions are the same as in Example 1, and a pure organic dynamic cross-linked polymer electrolyte membrane is prepared.

[0054] Comparative Example 2 Step 2 was replaced by: under nitrogen protection, 8.0 g of polyethylene glycol diacrylate (PEGDAC, molecular weight 1000) was mixed and dissolved with 120 mL of DMF, and 15.0 g of LiTFSI was added and stirred to dissolve, so as to obtain a prepolymer solution; the remaining steps, raw material amounts, and reaction conditions were the same as in Example 1, and a polymer electrolyte membrane containing a functionalized inorganic phase but without dynamic acylhydrazone bonds was prepared.

[0055] Furthermore, performance tests were conducted on the above embodiments and comparative examples. The test methods are as follows, and the test results are shown in Table 1: 1. High and low temperature performance: After being fully charged at 0.2C, it was placed in an oven at 25℃, 35℃, 0℃, and -10℃ for 4 hours respectively, and then discharged at a rate of 0.2C.

[0056] 2. Tensile strength: A universal testing machine was used, with a tensile rate of 5 mm / min, and the average value of 5 tests was taken.

[0057] 3. Room temperature ionic conductivity: determined using AC impedance spectroscopy (frequency range 10). - ¹-106 The conductivity σ = L / (R×S) was measured at Hz (amplitude 5mV), where L is the film thickness, R is the impedance value, and S is the electrode area.

[0058] Table 1 Test results for each embodiment and comparative example

[0059] As shown in Table 1, the room temperature ionic conductivity of Examples 1-8 is all around 1.5 × 10⁻⁶. -3 ~3.0×10 -3 Within the S / cm range, the conductivity was significantly higher than that of Comparative Example 1. This is because Comparative Example 1 lacked the SH-LLZTO-functionalized inorganic phase and relied solely on the acylhydrazone coordination channels of the organic phase for lithium ion transport, resulting in higher resistance. In contrast, the hydrophilic channels constructed with SH-LLZTO in the examples synergistically interacted with the organic phase channels, reducing ion transport resistance. Example 4, due to its higher MPTES content, had a higher thiol group density on the SH-LLZTO surface, leading to more complete cross-linking with the organic phase, better channel continuity, and the best conductivity. Example 6, due to insufficient SH-LLZTO addition, had fewer channels and the lowest conductivity.

[0060] The tensile strengths of Examples 1-8 ranged from 1.8 to 3.8 MPa, significantly higher than Comparative Example 1. This is mainly because the rigid framework of SH-LLZTO is embedded in the organic network through chemical bonding, bearing external stress and improving the mechanical properties of the membrane. Example 7, with the highest SH-LLZTO content, exhibited the most significant rigidity enhancement, achieving a tensile strength of 3.8 MPa. Example 6, with insufficient SH-LLZTO, had the weakest reinforcing effect and the lowest strength. Comparative Example 2, lacking dynamic acylhydrazone bonds and having a static crosslinking structure, had strength similar to the examples but lacked self-healing properties. The self-healing efficiency of Examples 1-8 was 83%-90%, while that of Comparative Example 2 was only 12%. The core reason is that Comparative Example 2 used static crosslinking bonds (acrylate double bond polymerization), where damaged chemical bonds cannot be reversibly reformed; in the examples, the dynamic acylhydrazone bonds could break and reform at room temperature, achieving crack healing. Example 4 had the highest self-healing efficiency due to the optimal match between acylhydrazone bond density and crosslinking degree.

[0061] Furthermore, from Figure 2It can be seen that the high and low temperature performance of Examples 1 and 4 is significantly better than that of Comparative Examples 1 and 2. The core reason is that both examples simultaneously possess the synergistic structure of thiol-modified nano-LLZTO (SH-LLZTO) functionalized inorganic phase and dynamic acylhydrazone bonds. In contrast, Comparative Example 1 lacks SH-LLZTO, and Comparative Example 2 lacks dynamic acylhydrazone bonds, both exhibiting key structural shortcomings. Comparative Example 1 is a pure organic dynamic cross-linked system, lacking an inorganic rigid framework and hydrophilic ion channels. Under high and low temperatures, the mobility of organic phase chain segments is severely affected, resulting in a sharp increase in ion transport resistance and a significant deterioration in structural and thermal stability. Although Comparative Example 2 has SH-LLZTO, it is a static cross-linked structure. The irreversible cross-linking bonds make its self-repair mechanism almost ineffective at high and low temperatures, and it is also prone to internal stress cracks due to thermal expansion and contraction, resulting in insufficient ion transport flexibility. In contrast, Examples 1 and 4... SH-LLZTO not only constructs hydrophilic ion channels that are minimally affected by temperature, forming a dual ion transport pathway with the organic phase acylhydrazone coordination channels, but its rigid framework is also chemically bonded into the organic network, inhibiting the temperature-sensitive degradation of organic chain segments and maintaining structural stability at high and low temperatures. The dynamic acylhydrazone bonds, through reversible nucleophilic addition-elimination reactions, ensure self-repair efficiency at high and low temperatures, and can also buffer internal stresses caused by thermal expansion and contraction, avoiding the generation of microcracks and always maintaining the integrity of the ion transport pathway and structure. Furthermore, in Example 4, due to the higher amount of MPTES, the surface thiol density of SH-LLZTO is greater, and the cross-linking with the organic phase is more complete, resulting in better continuity of the dual ion channels, structural compactness, and dynamic acylhydrazone recombination efficiency, and more outstanding high and low temperature performance than in Example 1.

[0062] Furthermore, from Figure 3 It can be seen that Example 4 has a lower impedance than Comparative Example 1. The core reason is that Example 4 uses a higher amount of MPTES, resulting in a higher surface thiol density and more complete cross-linking with the organic phase. This not only constructs a dual lithium-ion transport path of "organic phase acylhydrazone coordination channel + inorganic phase surface hydrophilic channel", but also significantly reduces the intrinsic resistance of ion transport compared to Comparative Example 1, which relies on only a single organic phase acylhydrazone coordination channel. Furthermore, the rigid framework of SH-LLZTO suppresses organic chain entanglement, and the resulting dense inorganic-organic interpenetrating network makes the ion transport channel more continuous, effectively reducing interfacial impedance. In contrast, Comparative Example 1 lacks the SH-LLZTO functionalized inorganic phase, and the pure organic system is prone to chain entanglement, with a single and poorly continuous ion transport channel, ultimately exhibiting higher impedance.

[0063] It is understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of this disclosure, and this disclosure is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and substance of this disclosure, and these modifications and improvements are also considered to be within the scope of protection of this disclosure.

Claims

1. A method for preparing a self-healing polymer electrolyte for energy storage and frequency modulation, characterized in that, include: Under an inert atmosphere and with the aid of a catalyst, the reaction of Li with 3-mercaptopropyltriethoxysilane was carried out. 6.4 La3Zr 1.4 Ta 0.6 O 12 Surface modification of nanocrystals was performed by grafting thiol groups via silanol condensation reaction. After separation, washing, and drying, thiol-modified Li was obtained. 6.4 La3Zr 1.4 Ta 0.6 O 12 Functionalized inorganic phases; In an inert atmosphere, using polyethylene glycol diamine and 2,5-dicarboxyfuran as raw materials, a linear prepolymer containing dynamic furanoylhydrazone bonds was constructed through nucleophilic addition-elimination reaction of amino and aldehyde groups. An electrolyte salt was added to the linear prepolymer, and after dissolution, a precursor prepolymer solution containing dynamic bonds was obtained. The thiol-modified Li 6.4 La3Zr 1.4 Ta 0.6 O 12 The functionalized inorganic phase is combined with the precursor prepolymer liquid containing dynamic bonds, and a crosslinking agent and a photoinitiator are added. Under ultraviolet-thermal dual initiation conditions, a three-dimensional interpenetrating network structure is constructed by crosslinking the inorganic phase and the organic phase through mercapto-olefin click reaction and furanoylhydrazone bond strengthening reaction, resulting in a gel-like composite film. The gel-like composite membrane was subjected to gradient heating and vacuum drying to obtain a functionalized inorganic phase-enhanced dynamically cross-linked polymer electrolyte membrane.

2. The preparation method according to claim 1, characterized in that, The 3-mercaptopropyltriethoxysilane and the Li 6.4 La3Zr 1.4 Ta 0.6 O 12 The mass ratio of nanocrystals is (0.3~0.7):1; The Li 6.4 La3Zr 1.4 Ta 0.6 O 12 Nanocrystals are pure cubic phases with a particle size ranging from 40 to 80 nm and a bulk ionic conductivity at room temperature ≥ 2 × 10⁻⁶. -4 S / cm; The surface modification temperature is 65-75℃, and the time is 3.5-4.5h.

3. The preparation method according to claim 1, characterized in that, In the case of the mercapto-modified Li 6.4 La3Zr 1.4 Ta 0.6 O 12 When the functionalized inorganic phase is compounded with the precursor prepolymer containing dynamic bonds, the thiol-modified Li 6.4 La3Zr 1.4 Ta 0.6 O 12 The mass ratio of the added functionalized inorganic phase to polyethylene glycol diamine is (0.5~3.0):

8.

4. The preparation method according to claim 1, characterized in that, The mass ratio of polyethylene glycol diamine to 2,5-dicarboxyfuran is 1:(1~1.2); Using polyethylene glycol diamine and 2,5-dicarboxyfuran as raw materials, a nucleophilic addition-elimination reaction between amino and aldehyde groups is carried out, including: first, dissolving polyethylene glycol diamine and N,N-dimethylformamide completely under magnetic stirring, cooling to 20-30℃, adding a DMF solution of 2,5-dicarboxyfuran dropwise, and stirring for 1-3 hours.

5. The preparation method according to claim 1, characterized in that, The electrolyte salt is lithium bis(trifluoromethanesulfonyl)imide, and the mass ratio of the electrolyte salt to polyethylene glycol diamine is (1.5~2.0):

1.

6. The preparation method according to claim 1, characterized in that, The crosslinking agent is trimethylolpropane triacrylate or pentaerythritol triacrylate; the mass ratio of the crosslinking agent to the polyethylene glycol diamine is (0.2~0.3):

1.

7. The preparation method according to claim 1, characterized in that, The ultraviolet-thermal dual initiation conditions include: ultraviolet light wavelength of 365nm, irradiation time of 20~40min; thermal initiation temperature of 50~70℃, and heat preservation time of 1~3h.

8. The preparation method according to claim 1, characterized in that, The gradient temperature vacuum drying includes: first vacuum drying at 40~60℃ for 5~7 hours, and then vacuum drying at 80~100℃ for 10~14 hours.

9. The preparation method according to claim 1, characterized in that, The polymer electrolyte membrane has an interpenetrating network of inorganic backbone and organic segments, as well as furanylhydrazone coordination channels in the organic phase and Li 6.4 La3Zr 1.4 Ta 0.6 O 12 Bulk fast ion channels, Li 6.4 La3Zr 1.4 Ta 0.6 O 12 Triple ion transport pathways in surface hydrophilic channels.

10. A self-healing polymer electrolyte for energy storage frequency regulation, characterized in that, The self-healing polymer electrolyte is prepared by the preparation method described in any one of claims 1-9.

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