Self-healing gel polymer electrolyte membrane, preparation method and application in energy storage battery

Abstract

This invention relates to the field of polymer electrolyte technology, specifically to a self-healing gel polymer electrolyte membrane, its preparation method, and its application in energy storage batteries. The method involves dissolving diamine-terminated polyethylene glycol (PEG) in an organic solvent, adding trimesic acid under an inert atmosphere, heating and stirring to form a prepolymer solution, cooling, adding glyoxylic acid and glacial acetic acid, and reacting at a constant temperature to obtain solution A. LiTFSI is added to solution A and ultrasonically dispersed to a homogeneous phase. The resulting slurry is poured onto a template, dried, and cured to obtain the self-healing gel polymer electrolyte membrane. A rigid aromatic crosslinking agent is used to inhibit polymer crystallization and improve mechanical integrity. A dynamic covalent network based on imine bonds is introduced to achieve autonomous interface repair at battery operating temperatures. Simultaneously, PEG ether oxygen chains are used to construct efficient lithium-ion transport channels, thus overcoming the technical limitations of traditional GPE in synergistically optimizing conductivity, mechanical strength, and interface stability.

Description

Technical Field

[0001] This invention relates to the field of polymer electrolyte technology, specifically to a self-healing gel polymer electrolyte membrane, its preparation method, and its application in energy storage batteries. Background Technology

[0002] Liquid electrolytes, due to their excellent ionic conductivity (up to 10⁻⁶) at room temperature, -3 ~10 -2 S cm -1 Liquid electrolytes, with their excellent interfacial compatibility with electrode materials, play a crucial role in the electrochemical energy storage system of lithium-ion batteries. However, their inherent flammability, especially in large-scale industrial applications such as electric vehicles, poses serious safety hazards. Despite efforts to improve safety through strategies such as developing novel electrolyte systems, introducing functional additives, or improving electrode materials, the inherent leakage risk, thermal runaway induced by internal short circuits, and even combustion problems of liquid electrolytes remain difficult to eliminate fundamentally. Solid-state electrolytes, as a potential alternative, have attracted attention due to their ability to effectively suppress electrolyte leakage and lithium dendrite growth, and are expected to solve safety issues. However, existing solid-state electrolytes generally suffer from insufficient room-temperature ionic conductivity (typically 10). -8 ~10 -6 S cm -1 The defects of the electrode make it difficult to meet the requirements of high energy density batteries for ion transport efficiency; at the same time, the poor physical contact between the electrode and the solid-solid interface significantly reduces the cycle stability of the battery.

[0003] Gel polymer electrolytes (GPEs) consist of a polymer network matrix that encapsulates a liquid electrolyte, aiming to combine the advantages of liquid and solid electrolytes. The polymer backbone provides the electrolyte system with good mechanical integrity and adhesion to the electrodes, helping to suppress lithium dendrite growth and improve safety; the encapsulated liquid electrolyte provides a high ion conduction channel (typically up to 10 Ω·cm at room temperature). -3 Scm -1(On the order of magnitude). Furthermore, the inherent flexibility of GPE allows it to adapt to volume changes in the electrode during charging and discharging, and it is easily constructed into complex shapes, providing a suitable electrolyte solution for flexible and wearable electronic devices. Nevertheless, the performance of GPE still faces several key bottlenecks: its room-temperature ionic conductivity, while higher than that of solid electrolytes, is still lower than that of pure liquid electrolytes, and it significantly decreases under low-temperature or high-rate conditions; there is an inherent constraint between the mechanical strength provided by the polymer matrix and the achievement of high ionic conductivity, making it difficult to achieve both simultaneously; insufficient long-term interfacial stability with highly active electrodes (such as lithium metal anodes and high-voltage cathodes), with continuous interfacial side reactions leading to increased interfacial impedance and capacity decay; the electrochemical stability window of existing GPE systems is insufficient to meet the requirements of advanced high-energy-density electrode materials; cycle life, thermal stability, and effective suppression of lithium dendrites still need further improvement. These key performance bottlenecks limit the commercial application potential of GPE in high-performance, high-safety energy storage systems (such as lithium metal batteries). Summary of the Invention

[0004] To address the challenges of balancing mechanical strength and ionic conductivity, as well as insufficient interfacial stability with highly active electrodes, in existing GPE polymer electrolytes, this invention provides a self-healing gel polymer electrolyte membrane, its preparation method, and its application in energy storage batteries. It innovatively proposes a "rigid framework-dynamic network" interpenetrating structure solution. A rigid aromatic crosslinking agent (trimethylammonium benzoate, TMA) is used to inhibit polymer crystallization and enhance mechanical integrity. A dynamic covalent network based on imine bonds (Schiff bases) is introduced to achieve autonomous interfacial repair at the battery's operating temperature (60°C). Simultaneously, polyethylene glycol ether oxygen chains are used to construct efficient lithium-ion transport channels, thereby overcoming the technical limitations of traditional GPE in synergistically optimizing ionic conductivity, mechanical strength, and interfacial stability.

[0005] This invention is achieved through the following technical solution:

[0006] A method for preparing a self-healing gel polymer electrolyte membrane, comprising:

[0007] Diamino-terminated polyethylene glycol was dissolved in an organic solvent. Trimethylbenzene was added under an inert atmosphere. After heating and stirring, a prepolymer solution was formed. After cooling, glyoxylic acid and glacial acetic acid were added. The mixture was then reacted at a constant temperature to obtain solution A.

[0008] LiTFSI was added to solution A and ultrasonically dispersed until homogeneous. The resulting slurry was poured onto a template and dried and cured to obtain a self-healing gel polymer electrolyte membrane.

[0009] Preferably, the ratio of the diamine-terminated polyethylene glycol to the organic solvent is 1:3;

[0010] The mass ratio of the diamino-terminated polyethylene glycol to pyromellitic acid is 100:2.8-8.4.

[0011] The mass ratio of pyromellitic acid: glyoxylic acid: glacial acetic acid is 2.8–8.4: 2.96–8.88: 2.4–3.6.

[0012] Preferably, the ultrasonic dispersion power is 300W and the time is 10±1min;

[0013] Preferably, the conditions for heating and stirring the reaction are: stirring at a temperature of 75-85℃ for 60±5 min; cooling at a temperature of 35-45℃; and constant temperature reaction time of 30±2 min.

[0014] Preferably, the organic solvent is acetonitrile, and the inert atmosphere is nitrogen.

[0015] Preferably, the specific process after the drying and curing reaction is as follows:

[0016] The slurry is poured onto a polytetrafluoroethylene (PTFE) plate, and the thickness is controlled to be 50-200 μm using a scraper. The PTFE plate with the slurry poured is then transferred to a forced-air drying oven at 55-65℃ for 2-6 hours until the film surface has no liquid phase gloss. After drying, it is transferred to a vacuum drying oven at 75-95℃ and a vacuum degree ≤-0.1 MPa for 4-8 hours. After film formation, it is left to stand for 24 hours at 25±2℃ and 60±5% RH to complete the activation of the self-healing function and obtain a self-healing gel polymer electrolyte membrane.

[0017] Preferably, after adding glyoxylic acid and glacial acetic acid, the pH of the reaction system is controlled at 4.8 to 5.2.

[0018] A self-healing gel polymer electrolyte membrane is prepared based on the aforementioned method for preparing a self-healing gel polymer electrolyte membrane.

[0019] Preferably, the structural formula of the self-healing gel polymer electrolyte membrane is:

[0020]

[0021] Application of a self-healing gel polymer electrolyte membrane in energy storage batteries; application of a self-healing gel polymer electrolyte membrane in semi-solid lithium batteries.

[0022] Compared with the prior art, the present invention has the following beneficial technical effects:

[0023] This invention is based on a triple synergistic mechanism of "rigid framework-flexible conductor-dynamic network," achieving precise structure-function control through molecular design and breaking through the performance boundaries of traditional gel polymer electrolytes. Specifically, the rigid aromatic crosslinked network constructed from trimesolic acid (TMA) effectively inhibits the crystallization of polyethylene glycol (PEG) chains and significantly enhances the mechanical integrity and dimensional stability of the electrolyte membrane; simultaneously, the PEG segments construct efficient lithium-ion transport channels through their continuous ether oxygen units, ensuring excellent ionic conductivity. Furthermore, the electrolyte membrane is endowed with a crucial self-healing capability through a dynamic covalent cross-linking network of imine bonds (-C=N-) formed by the reaction of glyoxylic acid with the terminal amino groups of bi-amino polyethylene glycol (H2-N-PEG-NH2) under acidic catalysis. This dynamic bond exhibits moderate reversibility (hydrolysis and recondensation equilibrium) at the battery operating temperature (~60℃). When micro-damage occurs at the interface or inside the membrane, the imine bonds at the damaged sites can break and recombine in new locations, achieving autonomous repair of the microstructure. This effectively suppresses the growth of electrode / electrolyte interface impedance and maintains tight interfacial contact. Ultimately, these three elements work synergistically through a three-dimensional interpenetrating network: the rigid network dissipates mechanical stress, the dynamic network repairs damage and buffers electrode volume changes through reversible bond recombination, and the flexible segments maintain ion transport continuity. This significantly extends the electrochemical stability and cycle life of the electrolyte membrane over a wide temperature range and under high-rate charge-discharge conditions, providing a comprehensive solution for high-safety lithium metal batteries.

[0024] The polymer electrolyte membrane of this invention exhibits breakthroughs in multiple dimensions: in terms of electrochemical performance, the room temperature ionic conductivity reaches 1.28 × 10⁻⁶. -4 The tensile strength was maintained at 4.1 MPa through molecular chain entanglement and cross-linking network regulation, while the interfacial stability was also improved. The assembled lithium battery achieved an initial discharge specific capacity of 154 mAh·g at 0.5C rate. -1 This provides a completely new approach for high-safety, long-life semi-solid-state batteries. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 Cycling diagrams at different rates are shown for the polymer electrolyte membranes prepared in Example 5 and the comparative example after they were assembled into batteries.

[0027] Figure 2EIS impedance spectra of the polymer electrolyte membranes prepared in Example 5 and the comparative example after being assembled into batteries and tested after 100 cycles.

[0028] Figure 3 The image shows a comparison of the voltammetric curves of the polymer electrolyte membrane prepared in Example 5. Detailed Implementation

[0029] 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 only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0030] In this invention, the term "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0031] In this invention, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can both represent: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0032] It should be understood that in various embodiments of the present invention, the order of the above-mentioned processes does not imply the order of execution. Some or all steps may be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0033] The terminology used in the embodiments of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms “a,” “the,” and “the” as used in the embodiments of this invention and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0034] The weights of the relevant components mentioned in the embodiments of this invention can refer not only to the specific content of each component, but also to the proportional relationship between the weights of the components. Therefore, any scaling up or down of the content of the relevant components according to the embodiments of this invention is within the scope disclosed in the embodiments of this invention. Specifically, the mass described in the embodiments of this invention can be a mass unit known in the chemical industry, such as μg, mg, g, or kg.

[0035] This invention provides a method for preparing a self-healing gel polymer electrolyte membrane, comprising:

[0036] Dissolve 100 parts by weight of diamino-terminated polyethylene glycol (H2N-PEG-NH2) in 300 parts by weight of acetonitrile. Under nitrogen protection, add 2.8–8.4 parts by weight of trimellitic acid (TMA), heat to 75–85°C, and stir for 60 ± 5 min to form a transparent, viscous prepolymer solution. Cool to 35–45°C, add 2.96–8.88 parts by weight of glyoxylic acid and 2.4–3.6 parts by weight of glacial acetic acid (pH controlled at 4.8–5.2), and react at a constant temperature for 30 ± 2 min. The solution changes from colorless to... The light yellow slurry was mixed with 19.2 parts LiTFSI and ultrasonically dispersed (300W, 10±1min) until homogeneous. The slurry was then poured onto a polytetrafluoroethylene (PTFE) plate, with the thickness controlled at 50-200μm using a scraper. The PTFE plate containing the slurry was then transferred to a forced-air drying oven at 55-65℃ for 2-6 hours, until the membrane surface showed no liquid phase gloss. Afterward, it was transferred to a vacuum drying oven at 75-95℃, with a vacuum degree ≤-0.1Mpa, for 4-8 hours. The resulting membrane was then allowed to stand at 25±2℃ and 60±5%RH for 24 hours to activate its self-healing function, yielding a self-healing gel polymer electrolyte membrane.

[0037] In some embodiments, the amount of trimesic acid is 12.8 to 8.4 parts by weight.

[0038] In some embodiments, the glyoxylic acid content is 2.96 to 8.88 parts by weight.

[0039] In some embodiments, the glacial acetic acid is present in parts by weight of 2.4 to 3.6.

[0040] This invention prepares a self-healing gel polymer electrolyte membrane using the above-described preparation method. The structural formula of the main polymer in the self-healing gel polymer electrolyte membrane is shown below:

[0041]

[0042] This invention is based on a ternary synergistic mechanism of "rigid framework-dynamic imine bond-flexible ion channel," achieving a synergistic breakthrough in self-healing properties, mechanical strength, and ion transport efficiency through molecular-level topological structure design. The rigid aromatic ring of TMA locks the molecular conformation of the imine bond (-N=CH-) through steric hindrance, forming a bidentate coordination structure with the carboxyl group of glyoxylic acid and the terminal amine of PEG. This significantly improves the hydrolytic stability of the dynamic bond in the electrolyte environment, overcoming the easy decomposition defect of traditional imine bonds. The TMA crosslinking domain and the flexible PEG chain form a microphase-separated structure, where the rigid phase inhibits PEG chain crystallization and provides mechanical support; the flexible phase contains ether oxygen bonds (COC) and Li... + Coordination forms a continuous transport channel, enabling room temperature ionic conductivity to exceed 2×10⁻⁶. -3 S cm -1 Dynamic imine bonds undergo reversible recombination mediated by water molecules in a 60% RH environment (reaction formula: This enables room-temperature self-healing of microcracks at the electrode / electrolyte interface, reducing the interfacial impedance growth rate to <5%.

[0043] Applying the self-healing gel polymer electrolyte membrane provided by this invention to semi-solid lithium batteries in the field of energy storage can significantly improve the discharge specific capacity of semi-solid lithium batteries.

[0044] In the following embodiments, unless otherwise specified, all materials used can be obtained through ordinary channels; the testing methods used are conventional methods in the art.

[0045] Example 1

[0046] 100g of amino-terminated polyethylene glycol (H2N-PEG-NH2) was dissolved in 300g of acetonitrile. Under nitrogen protection, 5.6g of trimellitic acid (TMA) was added. The mixture was heated to 80℃ and stirred for 60min to form a transparent, viscous prepolymer solution. The temperature was then lowered to 40℃, and 5.92g of glyoxylic acid and 2.4g of glacial acetic acid were added (pH controlled at 4.8–5.2). The mixture was kept at a constant temperature for 30min, during which the solution changed from colorless to pale yellow. 19.2g of [unspecified ingredient] was then added. Lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) was ultrasonically dispersed (300W, 10 min) until homogeneous. The slurry was poured onto a polytetrafluoroethylene (PTFE) plate, with the thickness controlled to 100 μm using a doctor blade. The PTFE plate with the poured slurry was then transferred to a forced-air drying oven at 60℃ for 4 h, until the membrane surface showed no liquid phase gloss. Afterward, it was transferred to a vacuum drying oven at 85℃, with a vacuum degree ≤-0.1 MPa, for 6 h. The film was then allowed to stand at 25℃ and 60% RH for 24 h to activate its self-healing function, resulting in the self-healing gel polymer electrolyte membrane HAPEM1.

[0047] The HAPEM1 prepared in this embodiment was assembled with a positive electrode (lithium iron phosphate) and a negative electrode (lithium metal sheet) into a 2025 model button cell. Performance testing was conducted, and the conductivity at room temperature was measured to be 1.33 × 10⁻⁶. -4 S / cm -1 To test the application of polymer electrolytes in all-solid-state lithium batteries, a LiFePO4 / HAPEM1 / Li battery was assembled and charged-discharge cycled at 60°C. The initial discharge specific capacity of the battery at a 0.5C rate was measured to be 151 mAh·g. -1 .

[0048] In some embodiments, the amount of trimesic acid is 2.8 to 8.4 parts by weight.

[0049] In some embodiments, the glyoxylic acid content is 2.96 to 8.88 parts by weight.

[0050] In some embodiments, the glacial acetic acid is present in parts by weight of 2.4 to 3.6.

[0051] Example 2

[0052] The preparation method of the polymer electrolyte membrane in this embodiment is basically the same as that in Example 1, except that the mass of pyromellitic acid is 2.8g, and a self-healing gel polymer electrolyte membrane HAPEM2 is obtained.

[0053] Insufficient cross-linking results in low polymer film strength, making it prone to sticking to battery structural components. This leads to significant processing difficulties during battery assembly and hinders the achievement of battery testing functions.

[0054] Example 3

[0055] The preparation method of the polymer electrolyte membrane in this embodiment is basically the same as that in Example 1, except that the mass of pyromellitic acid is 8.4g, and a self-healing gel polymer electrolyte membrane HAPEM3 is obtained.

[0056] Excessive cross-linking results in excessively rigid polymer films that are prone to breakage, making battery assembly more difficult and hindering battery testing capabilities.

[0057] Example 4

[0058] The preparation method of the polymer electrolyte membrane in this embodiment is basically the same as that in Example 1, except that the mass of glacial acetic acid is 2.4g, and a self-healing gel polymer electrolyte membrane HAPEM4 is obtained.

[0059] The HAPEM4 prepared in this embodiment was assembled with a positive electrode (lithium iron phosphate) and a negative electrode (lithium metal sheet) into a 2025 model button cell. Performance testing was conducted, and the conductivity at room temperature was measured to be 1.32 × 10⁻⁶. -4 S / cm-1 To test the application of polymer electrolytes in all-solid-state lithium batteries, a LiFePO4 / HAPEM1 / Li battery was assembled and charged-discharge cycled at 60°C. The initial discharge specific capacity of the battery at a 0.5C rate was measured to be 152 mAh·g. -1 .

[0060] Example 5

[0061] The preparation method of the polymer electrolyte membrane in this embodiment is basically the same as that in Example 1, except that the mass of glacial acetic acid is 3.6g, and a self-healing gel polymer electrolyte membrane HAPEM5 is obtained.

[0062] The HAPEM5 prepared in this embodiment was assembled with a positive electrode (lithium iron phosphate) and a negative electrode (lithium metal sheet) into a 2025 model button cell. Performance testing was conducted, and the conductivity at room temperature was measured to be 1.28 × 10⁻⁶. -4 S / cm -1 To test the application of polymer electrolytes in all-solid-state lithium batteries, a LiFePO4 / HAPEM5 / Li battery was assembled and charged-discharge cycled at 60°C. The initial discharge specific capacity of the battery at a 0.5C rate was measured to be 154 mAh·g. -1 .

[0063] Example 6

[0064] The preparation method of the polymer electrolyte membrane in this embodiment is basically the same as that in Example 1, except that the mass of glyoxylic acid is 2.96g, and a self-healing gel polymer electrolyte membrane HAPEM6 is obtained.

[0065] The HAPEM6 prepared in this embodiment was assembled with a positive electrode (lithium iron phosphate) and a negative electrode (lithium metal sheet) into a 2025 model button cell. Performance testing was conducted, and the conductivity at room temperature was measured to be 1.36 × 10⁻⁶. -4 S / cm -1 To test the application of polymer electrolytes in all-solid-state lithium batteries, they were assembled into LiFePO4 / HAPEM6 / Li batteries and charged-discharge cycles were tested at 60°C. The initial discharge specific capacity of the battery at a 0.5C rate was measured to be 147 mAh·g. -1 .

[0066] Example 7

[0067] The preparation method of the polymer electrolyte membrane in this embodiment is basically the same as that in Example 1, except that the mass of glyoxylic acid is 8.88g, and a self-healing gel polymer electrolyte membrane HAPEM7 is obtained.

[0068] The HAPEM7 prepared in this embodiment was assembled with a positive electrode (lithium iron phosphate) and a negative electrode (lithium metal sheet) into a 2025 model button cell. Performance testing was conducted, and the conductivity at room temperature was measured to be 1.53 × 10⁻⁶. -4 S / cm -1 To test the application of polymer electrolytes in all-solid-state lithium batteries, they were assembled into LiFePO4 / HAPEM6 / Li batteries and charged-discharge cycles were tested at 60°C. The initial discharge specific capacity of the battery at a 0.5C rate was measured to be 145 mAh·g. -1 .

[0069] Comparative Example 1

[0070] The specific steps for preparing the polymer electrolyte membrane in Comparative Example 1 are as follows: 1.00 g of polyvinylidene difluoride (PVDF) and 0.20 g of LiTFSI were dissolved in 10 ml of N-methylpyrrolidone (NMP) solution. The resulting solution was poured onto the surface of a glass mold and dried in a vacuum environment at 60 °C for 12 hours to obtain the polymer electrolyte membrane, denoted as PVDF. It was assembled into a LiFePO4 / PVDF / Li battery, and its charge-discharge cycle performance was tested at 60 °C. The conductivity of the polymer electrolyte membrane at room temperature was measured to be 5.36 × 10⁻⁶. -5 S / cm -1 The initial discharge specific capacity of the battery, measured at a 0.5C rate, was 93 mAh·g. -1 .

[0071] Example 8

[0072] 100g of amino-terminated polyethylene glycol (H2N-PEG-NH2) was dissolved in 300g of acetonitrile. Under nitrogen protection, 5.6g of trimesic acid (TMA) was added. The mixture was heated to 85℃ and stirred for 65min to form a transparent, viscous prepolymer solution. The temperature was then lowered to 45℃, and 5.92g of glyoxylic acid and 2.4g of glacial acetic acid were added (pH controlled at 4.8–5.2). The mixture was kept at a constant temperature for 32min, during which the solution changed from colorless to pale yellow. 19.2g of [unspecified ingredient] was then added. Lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) was ultrasonically dispersed (300W, 11 min) until homogeneous. The slurry was poured onto a polytetrafluoroethylene (PTFE) plate, with the thickness controlled to 200 μm using a doctor blade. The PTFE plate with the poured slurry was then transferred to a forced-air drying oven at 65℃ for 2 h, until the membrane surface showed no liquid phase gloss. Afterward, it was transferred to a vacuum drying oven at 95℃, with a vacuum degree ≤-0.1 MPa, for 4 h. The film was then allowed to stand at 25℃ and 60% RH for 24 h to activate its self-healing function, resulting in the self-healing gel polymer electrolyte membrane HAPEM8.

[0073] The HAPEM8 prepared in this embodiment was assembled with a positive electrode (lithium iron phosphate) and a negative electrode (lithium metal sheet) into a 2025 model energy storage button battery. Performance testing was conducted, and the conductivity at room temperature was measured to be 1.35 × 10⁻⁶. -4 S / cm -1 To test the application of polymer electrolytes in all-solid-state lithium batteries, a LiFePO4 / HAPEM8 / Li battery was assembled and charged-discharge cycled at 60°C. The initial discharge specific capacity of the battery at a 0.5C rate was measured to be 150 mAh·g. -1 .

[0074] Example 9

[0075] 100g of amino-terminated polyethylene glycol (H2N-PEG-NH2) was dissolved in 300g of acetonitrile. Under nitrogen protection, 5.6g of trimellitic acid (TMA) was added. The mixture was heated to 75℃ and stirred for 55min to form a transparent, viscous prepolymer solution. The temperature was then lowered to 35℃, and 5.92g of glyoxylic acid and 2.4g of glacial acetic acid were added (pH controlled at 4.8–5.2). The mixture was kept at a constant temperature for 28min, during which the solution changed from colorless to pale yellow. 19.2g of [unspecified ingredient] was then added. Lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) was ultrasonically dispersed (300W, 11 min) until homogeneous. The slurry was poured onto a polytetrafluoroethylene (PTFE) plate, with the thickness controlled to 50 μm using a doctor blade. The PTFE plate with the slurry was then transferred to a forced-air drying oven at 55℃ for 6 h, until the membrane surface showed no liquid phase gloss. Afterward, it was transferred to a vacuum drying oven at 75℃, with a vacuum degree ≤-0.1 MPa, for 8 h. The film was then allowed to stand at 25℃ and 60% RH for 24 h to activate its self-healing function, resulting in the self-healing gel polymer electrolyte membrane HAPEM9.

[0076] The HAPEM9 prepared in this embodiment was assembled with a positive electrode (lithium iron phosphate) and a negative electrode (lithium metal sheet) into a 2025 model energy storage button battery. Performance testing was conducted, and the conductivity at room temperature was measured to be 1.31 × 10⁻⁶. -4 S / cm -1 To test the application of polymer electrolytes in all-solid-state lithium batteries, a LiFePO4 / HAPEM9 / Li battery was assembled and charged-discharge cycled at 60°C. The initial discharge specific capacity of the battery at a 0.5C rate was measured to be 145 mAh·g. -1 .

[0077] Figure 1 The results show the rate performance of LFP|HAPEM5|Li and LFP|PVDF|Li batteries at 25°C. The discharge capacities of the lithium-ion battery assembled using HAPEM5 at 0.2, 0.5, and 1C are 157, 154, and 134 mAh g, respectively. -1For lithium metal batteries manufactured using PVDF, the corresponding values ​​are 105, 93, and 70 mAh g, respectively. -1 When the discharge rate is reduced to 0.2C, the discharge capacity of the lithium battery using HAPEM5 increases to 157 mAh g. -1 The discharge capacity of lithium batteries using PVDF only increased to 96 mAh g. -1 This indicates that HAPEM5 has good rate performance and capacity recovery performance.

[0078] Figure 2 The results show that the impedance of the LFP|HAPEM5|Li battery after 100 cycles (317Ω) is significantly lower than that of the LFP|PVDF|Li battery (1020Ω), which is directly attributed to the interfacial damage repair function of the dynamic network of imine bonds in the HAPEM5 electrolyte. During cycling, interfacial microcracks caused by lithium dendrite growth or electrode volume changes can disrupt the interfacial contact (PVDF-based electrolytes cannot repair such damage due to their static network, leading to continuous accumulation of interfacial impedance); while the imine bonds (-C=N-) in HAPEM5 can reconstitute the broken dynamic crosslinking points in real time through a reversible hydrolysis-recondensation reaction at the battery operating temperature (60℃), autonomously repairing interfacial micro-damage and maintaining a tight electrode / electrolyte contact. Simultaneously, the rigid TMA framework inhibits excessive swelling of the PEG chain segments, ensuring the stability of the ion transport channels; the flexible PEG chains continuously provide efficient lithium-ion conduction pathways. This triple synergistic mechanism jointly suppresses interfacial side reactions and impedance growth, enabling HAPEM5 to exhibit superior interfacial stability during long-term cycling.

[0079] Figure 3 This demonstrates that the LFP|HAPEM5|Li battery possesses an excellent electrochemical window, with the rigid TMA crosslinking network and stable dynamic chemical bonds providing synergistic protection. The aromatic conjugated structure of trimesic acid (TMA) endows the system with excellent antioxidant properties, inhibiting the oxidative decomposition of PEG segments. Meanwhile, the stable dynamic covalent network formed by imine bonds (-C=N-) under acidic catalytic conditions effectively suppresses side reactions of the electrolyte at high voltages (>4.7V). Simultaneously, the electrochemically inert TFSI- anion in LiTFSI further broadens the oxidation limit. The synergistic effect of these three factors gives the electrolyte high antioxidant properties.

[0080] Table 1 shows that HAPEM1 (4.9 MPa, 185%), HAPEM4 (3.2 MPa, 120%), HAPEM5 (4.1 MPa, 95%), HAPEM6 (4.3 MPa, 170%), and HAPEM7 (3 MPa, 210%) exhibit synergistic optimization of strength and toughness. This is attributed to the TMA rigid crosslinking network inhibiting PEG crystallization (improving strength / modulus), while the reversible breakage and recombination of imine dynamic bonds dissipates stress (ensuring ductility), achieving a balance between rigidity and flexibility. The high strength of HAPEM3 (>6.0 MPa, <10%) accompanied by extremely low ductility indicates excessive rigid crosslinking and insufficient dynamic network, leading to brittle fracture (impeded chain segment movement). The ultra-high ductility but sharp drop in strength / modulus of HAPEM2 (<1.0 MPa, >500%) reflects either an overly dense dynamic network or insufficient rigid crosslinking, resulting in a loose polymer network.

[0081] Table 1 shows the mechanical properties of the polymer electrolyte membranes from Examples 1 to 7.

[0082]

[0083] This invention constructs a "rigid-flexible, dynamically self-healing" gel electrolyte system based on molecular engineering strategies. Its core mechanism lies in: constructing a three-dimensional support network through a rigid aromatic crosslinking agent (trimethylammonium benzoate, TMA), which effectively suppresses the crystallization tendency of polyethylene glycol (PEG) segments and significantly improves the mechanical strength and dimensional stability of the electrolyte membrane; utilizing the continuous ether oxygen units in the flexible PEG long chain to construct an efficient lithium-ion transport channel, ensuring excellent ionic conductivity; the key innovation lies in the introduction of a dynamic reversible covalent network based on imine bonds (-C=N-) (formed by the reaction of glyoxylic acid and diamino-terminated PEG under acid catalysis), which has adaptive recombination capability at the battery operating temperature (~60℃). When the electrode / electrolyte interface suffers micro-damage due to lithium dendrites or volume changes during cycling, the imine bonds at the damaged sites can undergo reversible breakage and rapid recombination in adjacent locations, achieving in-situ autonomous repair of the microstructure. This effectively maintains tight interfacial contact and significantly suppresses the growth of interfacial impedance (e.g., the impedance of LFP|HAPEM5|Li after cycling is 317Ω, far lower than the 1020Ω of PVDF-based electrolytes). This synergistic effect of "rigid support, flexible ion conduction, and dynamic repair" jointly ensures the structural integrity and interfacial stability of the electrolyte during long-term cycling, ultimately achieving a breakthrough in the performance of high-safety, long-life lithium metal batteries.

[0084] Unless otherwise specified, all embodiments and preferred embodiments mentioned herein can be combined to form new technical solutions.

[0085] Unless otherwise specified, all the technical features and preferred features mentioned herein can be combined to form new technical solutions.

[0086] In this invention, unless otherwise specified, percentage (%) or parts refer to weight percentage or parts relative to the composition.

[0087] Unless otherwise specified, the components or preferred components involved in this invention can be combined with each other to form new technical solutions.

[0088] In this invention, unless otherwise specified, the numerical range "a~b" represents an abbreviation of any combination of real numbers between a and b, where a and b are both real numbers. For example, the numerical range "6~22" means that all real numbers between "6~22" have been listed in this document, and "6~22" is simply an abbreviation of these numerical combinations.

[0089] The "scope" disclosed in this invention can be in the form of a lower limit and an upper limit, and can be one or more lower limits and one or more upper limits, respectively.

[0090] In this invention, the term "and / or" as used herein refers to any combination of one or more of the associated listed items, as well as all possible combinations, and includes such combinations.

[0091] In this invention, unless otherwise stated, the various reactions or operation steps may be performed sequentially or in a particular order. Preferably, the reaction methods described herein are performed sequentially.

[0092] Unless otherwise stated, the technical and scientific terms used herein have the same meanings as those familiar to those skilled in the art. Furthermore, any methods or materials similar to or equivalent to those described herein may also be used in this invention.

[0093] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Those skilled in the art can readily implement the present invention based on the accompanying drawings and the above description. However, any modifications, alterations, or variations made by those skilled in the art without departing from the scope of the present invention, utilizing the disclosed technical content, are equivalent embodiments of the present invention. Furthermore, any modifications, alterations, or variations made to the above embodiments based on the essential technology of the present invention are still within the protection scope of the present invention.

Claims

1. A self-repairing gel polymer electrolyte film, characterized by, The structural formula of the self-healing gel polymer electrolyte membrane is: ； The method for preparing the self-healing gel polymer electrolyte membrane includes: Dissolve the diamino-terminated polyethylene glycol in an organic solvent, add pyromellitic acid under an inert atmosphere, heat and stir to form a prepolymer solution, cool down and add glyoxylic acid and glacial acetic acid, react at a constant temperature to obtain solution A. LiTFSI was added to solution A and ultrasonically dispersed until homogeneous. The resulting slurry was poured onto a template and dried and cured to obtain a self-healing gel polymer electrolyte membrane. The ratio of the diamine-terminated polyethylene glycol to the organic solvent is 1:3; The mass ratio of the diamino-terminated polyethylene glycol to pyromellitic acid is 100: 2.8~8.4; The mass ratio of pyromellitic acid: glyoxylic acid: glacial acetic acid is 2.8~8.4: 2.96~8.88: 2.4~3.

6.

2. The self-healing gel polymer electrolyte film according to claim 1, wherein, The ultrasonic dispersion power was 300W, and the time was 10±1 min.

3. The self-healing gel polymer electrolyte membrane according to claim 1, characterized in that, The conditions for heating and stirring the reaction are as follows: stirring at a temperature of 75~85℃ for 60±5 min; cooling at a temperature of 35~45℃; and constant temperature reaction for 30±2 min.

4. The self-healing gel polymer electrolyte membrane according to claim 1, characterized in that, The organic solvent is acetonitrile, and the inert atmosphere is nitrogen.

5. The self-healing gel polymer electrolyte membrane according to claim 1, characterized in that, The specific process after the drying and curing reaction is as follows: The slurry is poured onto a polytetrafluoroethylene (PTFE) plate, and the thickness is controlled to be 50-200 μm using a scraper. The PTFE plate with the slurry poured is then transferred to a forced-air drying oven at a temperature of 55-65℃ for 2-6 hours until the film surface has no liquid phase gloss. After drying, it is transferred to a vacuum drying oven at a curing temperature of 75-95℃ and a vacuum degree of ≤-0.1 MPa for 4-8 hours. After film formation, it is left to stand for 24 hours at 25±2℃ and 60±5%RH to complete the activation of the self-healing function and obtain a self-healing gel polymer electrolyte membrane.

6. The self-healing gel polymer electrolyte membrane according to claim 1, characterized in that, After adding glyoxylic acid and glacial acetic acid, the pH of the reaction system was controlled at 4.8~5.

2.

7. The application of the self-healing gel polymer electrolyte membrane according to claim 1 in an energy storage battery, characterized in that, Application of self-healing gel polymer electrolyte membranes in semi-solid lithium-ion batteries.

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