Self-repairing solid electrolyte, self-repairing solid battery and preparation method and application of self-repairing solid electrolyte and self-repairing solid battery

Abstract

The invention provides a self-repairing solid electrolyte, a self-repairing solid-state battery and a preparation method and application thereof, and belongs to the technical field of batteries. The self-repairing solid electrolyte comprises a self-repairing polymer matrix, a lithium salt and a dynamically rearranged chemical bond structure, the self-repairing polymer matrix contains a dynamic chemical bond, and the dynamic chemical bond comprises one or more of a reversible covalent bond, a metal-ligand coordination bond, a hydrogen bond and an ionic bond. A polymer network is constructed by introducing various reversible dynamic bonds, so that the oxide, sulfide or composite solid electrolyte material is endowed with self-healing capability; the self-repairing solid electrolyte can realize damage closing and multiple reversible repairing at room temperature; excellent capacity retention ratio is shown in a high-magnification cycle test; the electrolyte crack and the electrode interface defect can be repaired through multiple paths such as electrode / electrolyte integrated preparation and microcapsule auxiliary repair, and the cycle life and the safety of the battery are remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and in particular to a self-healing solid electrolyte, a self-healing solid battery, its preparation method and application. Background Technology

[0002] In recent years, solid-state batteries have received widespread attention due to their high energy density and safety. However, typical oxides (such as L...) L Z Solid electrolytes such as oxides and sulfides are mechanically brittle and prone to cracking, pulverization, or delamination from the electrodes under charge-discharge cycles or external stress. Crack formation or poor interfacial contact can lead to increased ion transport impedance, lithium dendrite puncture short circuits, and other problems, severely reducing battery cycle life and safety. To address these issues, the academic community has proposed various self-healing strategies. For example, polymer electrolytes with reversible disulfide and hydrogen bonds can form an integrated structure at the electrode interface, enabling automatic crack healing. Other approaches include using polymer electrolytes with dynamic metal-ligand coordination to enhance interfacial stability through delocalized electrons, or embedding microcapsules in the electrolyte to release repair agents. However, most of these methods are for polymer electrolytes or other energy storage devices, and specialized technologies for cracking in oxide / sulfide solid electrolytes are still immature. Furthermore, while microcapsule-based self-healing methods are simple and direct, they can only achieve single-use repair (efficiency of only ≈60%) and fail after the capsule ruptures.

[0003] Therefore, there is an urgent need to develop a multi-mechanism self-healing technology applicable to different types of solid electrolytes (oxides, sulfides, polymer complexes, etc.) to achieve long-term stable operation of solid batteries in applications such as power batteries and wearables. Summary of the Invention

[0004] The purpose of this invention is to provide a self-healing solid electrolyte, a self-healing solid battery, its preparation method and application, which addresses the shortcomings of the prior art. Through the synergistic effect of multiple dynamic bonds, it effectively repairs mechanical damage to the solid electrolyte layer and electrode interface, and significantly improves the battery cycle life and reliability.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a self-healing solid electrolyte comprising a self-healing polymer matrix, a lithium salt, and a dynamically rearrangeable chemical bond structure; the self-healing polymer matrix contains dynamic chemical bonds, which include one or more of reversible covalent bonds, metal-ligand coordination bonds, hydrogen bonds, and ionic bonds; The reversible covalent bonds include disulfide bonds or acylhydrazone bonds, and the hydrogen bonds include multiple hydrogen bonds.

[0006] Preferably, the metal-ligand coordination bond is a coordination bond network formed by the metal ion and the ligand.

[0007] Preferably, the metal ions include Zr. 4+ Cu 2+ and Zn 2+ One or more of them, the ligands of which include pyridine or carboxylates.

[0008] Preferably, the polymer matrix in the self-healing polymer matrix comprises polyurethane, polyamide, polycarbonate, polyethylene glycol block copolymer, or polyionic liquid; the lithium salt comprises LiFSI, LiTFSI, or LiCl. or LiP .

[0009] The present invention also provides a method for preparing the self-healing solid electrolyte, comprising the following steps: Polymer precursors and chain extenders are polymerized in a solvent to form a polymer network with reversible bonds; lithium salts are added to the polymer network to obtain a self-healing solid electrolyte.

[0010] Preferably, the polymer precursor comprises polyether and / or polyol, and the chain extender is a compound containing disulfide groups or carbon-carbon double bonds; the mass ratio of polymer network to lithium salt is 1~10:1; and the polymerization reaction temperature is 40~60℃.

[0011] The present invention also provides a self-healing solid-state battery, the self-healing solid-state battery comprising a positive electrode material, a negative electrode material, and a self-healing solid electrolyte membrane formed by curing the self-healing solid electrolyte into a film; The positive electrode material comprises a sulfide, a high-voltage oxide, or an air electrode, and the sulfide comprises L... S or sulfurized polyacrylonitrile, high-voltage oxide includes nickel cobalt manganese oxide or lithium iron phosphate composite oxide, and the negative electrode material is lithium or silicon. The curing temperature is 50~100℃, and the curing time is 1~24h.

[0012] Preferably, the surface of the self-healing solid electrolyte membrane or electrode is coated with a microcapsule layer. The shell of the microcapsule is a formaldehyde-urea-phenolic resin or polyurea, and the core material of the microcapsule is a repair agent. The repair agent contains one or more of RbNO3 solution, polymerizable monomers, and liquid metal. The concentration of RbNO3 solution is 0.5~2.0 mol / L. The coating thickness is 1~5 μm.

[0013] The present invention also provides a method for preparing the self-healing solid-state battery, comprising the following steps: casting or coating a self-healing solid electrolyte onto a thin film surface and then curing it into a film to form a self-healing solid electrolyte film; assembling the self-healing solid electrolyte film with a positive electrode material and a negative electrode material to form a self-healing solid-state battery, thereby achieving self-healing connection at the electrode / electrolyte interface; The self-healing solid electrolyte is a self-healing solid electrolyte solution or a self-healing solid electrolyte slurry, and the thin film is a positive electrode thin film or a negative electrode thin film.

[0014] The present invention also provides the application of the self-healing solid-state battery in power batteries or wearable devices.

[0015] The beneficial effects of this invention are: This invention addresses the problems of electrolyte layer cracking and electrode / electrolyte interface delamination in solid-state lithium batteries, proposing a novel self-healing solid-state battery based on multiple dynamic self-healing mechanisms; these mechanisms include: (1) Polymer electrolyte with reversible covalent and hydrogen bond synergy: A polymer matrix containing reversible disulfide bonds and cis-trans hydrogen bonds is blended with lithium salt or polymerized in situ to prepare a solid electrolyte membrane with self-healing function. This electrolyte can be integrated with the electrode casting and can quickly repair cracks and maintain interfacial contact without external force by utilizing the dynamic bond network.

[0016] (2) Metal-ligand coordination dynamic polymers: Introducing coordination centers containing high-valence metal ions (such as Zr) into the polymer backbone (such as polyurethane, polyamide, etc.). 4+ Cu 2+ Zn 2+ (etc.) to form a reversible coordination cross-linking network. This network not only endows the electrolyte with good mechanical strength and thermal stability, but also regulates the distribution of lithium ions through electron transfer mechanisms, achieving uniform deposition and preventing dendrite growth.

[0017] (3) Ion-interacting polymer electrolytes: Polymers (such as polyethylene glycol block copolymers, polyionic liquids, etc.) are combined with ionic liquids and lithium salts, and cross-linking is enhanced through quadruple hydrogen bonding, electrostatic adsorption, etc.; at the same time, the ionic liquid provides high ionic conductivity. This system has high ionic conductivity (up to 10). -3 It has a strength on the order of S / cm and a self-healing function, allowing it to quickly recover its structure after being damaged.

[0018] (4) Microcapsule-assisted repair: Microcapsules (with a polymer shell and a core containing a repair agent such as RbNO3 solution, polymerizable monomers, or liquid metal) are uniformly distributed on the surface of the electrolyte membrane or electrode. When cracks form, the capsules rupture, releasing the repair agent to fill the cracks. Microcapsules can be used to enhance one-time repairs (e.g., passivating lithium dendrites) or to inject liquid electrolytes to repair cracks.

[0019] (5) Dynamic hybrid systems: Combining the above mechanisms, such as introducing polymer networks containing multiple dynamic bonds (coordinate bonds, reversible covalent bonds, hydrogen bonds); or combining dynamic polymers with functional inorganic nanoparticles (such as LLZO nanofibers, Li 7- x L Z G The ceramics (LLZGO ceramics, etc.) are assembled into a composite electrolyte, giving it synchronous high conductivity and self-healing properties.

[0020] This invention introduces various reversible dynamic bonds (such as disulfide bonds, metal-ligand coordination bonds, hydrogen bonds, and ion interactions) to construct a polymer network, thereby endowing oxide, sulfide, or composite solid electrolyte materials with self-healing capabilities. This invention proposes multiple pathways, including dynamic polymer electrolytes, integrated electrode / electrolyte preparation, and microcapsule-assisted repair, which can repair electrolyte cracks and electrode interface defects, significantly improving battery cycle life and safety. The self-healing solid electrolyte can achieve damage closure at room temperature and reversibly repair multiple times. It exhibits excellent capacity retention in high-rate cycling tests (e.g., a capacity retention of over 93% after 700 cycles at 0.3C). The self-healing solid electrolyte of this invention is suitable for applications such as power batteries and wearable devices, and is expected to promote the application of next-generation high-performance solid-state lithium batteries. Detailed Implementation

[0021] This invention provides a self-healing solid electrolyte comprising a self-healing polymer matrix, a lithium salt, and a dynamically rearrangeable chemical bond structure; the self-healing polymer matrix contains dynamic chemical bonds, which include one or more of reversible covalent bonds, metal-ligand coordination bonds, hydrogen bonds, and ionic bonds; The reversible covalent bond preferably includes a disulfide bond or an acylhydrazone bond, and the hydrogen bond preferably includes multiple hydrogen bonds, with the multiple hydrogen bonds preferably being an UPy quadruple hydrogen bond system.

[0022] In this invention, the metal-ligand coordination bond is preferably a coordination bond network formed by the metal ion and the ligand, and the metal ion preferably contains Zr. 4+ Cu 2+ and Zn 2+ One or more of the ligands, preferably containing pyridine or carboxylates.

[0023] In this invention, the polymer matrix in the self-healing polymer matrix preferably comprises polyurethane, polyamide, polycarbonate, polyethylene glycol block copolymer or polyionic liquid; the lithium salt preferably comprises LiFSI, LiTFSI, LiClO4 or LiPF6; the lithium salt is a separable lithium salt.

[0024] In this invention, the synergistic effect of dynamic bonds in the self-healing polymer matrix enables the solid electrolyte material to have room temperature self-healing capability; the lithium salt is uniformly dispersed in the polymer matrix.

[0025] The present invention also provides a method for preparing the self-healing solid electrolyte, comprising the following steps: Polymer precursors and chain extenders are polymerized in a solvent to form a polymer network with reversible bonds; lithium salts are added to the polymer network to obtain a self-healing solid electrolyte.

[0026] In this invention, the polymer precursor preferably comprises polyether and / or polyol, and the chain extender is preferably a compound containing disulfide groups or carbon-carbon double bonds; the mass ratio of polymer network to lithium salt is preferably 1~10:1, more preferably 3~7:1, and even more preferably 4~5:1; the polymerization reaction temperature is preferably 40~60℃, more preferably 45~55℃, and even more preferably 50℃.

[0027] The present invention also provides a self-healing solid-state battery, the self-healing solid-state battery comprising a positive electrode material, a negative electrode material, and a self-healing solid electrolyte membrane formed by curing the self-healing solid electrolyte into a film; The positive electrode material comprises a sulfide, a high-voltage oxide, or an air electrode, and the sulfide comprises L... S or sulfurized polyacrylonitrile (SPAN), high-voltage oxide includes nickel cobalt manganese oxide (NCM) or lithium iron phosphate composite oxide (LFP), and the negative electrode material is lithium or silicon; The curing temperature is 50~100℃, and the curing time is 1~24h.

[0028] In this invention, the curing temperature is preferably 60~90℃, more preferably 70~80℃, and the curing time is preferably 3~20h, more preferably 5~15h, and even more preferably 10h.

[0029] In this invention, a microcapsule layer is coated on the surface of a self-healing solid electrolyte membrane or electrode. The shell of the microcapsule is preferably formaldehyde-urea-phenolic resin or polyurea, and the core material of the microcapsule is preferably a repair agent, which preferably contains RbN. One or more of the following: solution, polymerizable monomer, and liquid metal, RbN The concentration of the solution is preferably 0.5~2.0 mol / L, more preferably 0.8~1.6 mol / L, and even more preferably 1~1.2 mol / L; the coating thickness is preferably 1~5 μm, more preferably 2~4 μm, and even more preferably 3 μm.

[0030] In this invention, when microcracks are generated during the charging and discharging process of the battery, the microcapsules rupture under controlled temperature to release a repair agent, which repairs the cracks or promotes uniform lithium deposition.

[0031] The present invention also provides a method for preparing the self-healing solid-state battery, comprising the following steps: casting or coating a self-healing solid electrolyte onto a thin film surface and then curing it into a film to form a self-healing solid electrolyte film; assembling the self-healing solid electrolyte film with a positive electrode material and a negative electrode material to form a self-healing solid-state battery, thereby achieving self-healing connection at the electrode / electrolyte interface; The self-healing solid electrolyte is a self-healing solid electrolyte solution or a self-healing solid electrolyte slurry, and the thin film is a positive electrode thin film or a negative electrode thin film.

[0032] In the self-healing solid-state battery of the present invention, the solid electrolyte and the electrode can form an integrated structure, or the solid electrolyte can be tightly bonded to the electrode by a binder; after casting, it is hot-pressed or dried for shaping, and the temperature of hot-pressing or drying is preferably 50~120°C, more preferably 60~100°C, and even more preferably 70~80°C.

[0033] The present invention also provides the application of the self-healing solid-state battery in power batteries or wearable devices.

[0034] The multi-mechanism self-healing solid electrolyte of this invention can be adapted to different types of matrix materials: for oxide-based solid electrolytes (such as high-modulus ceramics), a "plastic-ceramic" hybridization strategy is used to hybridize the dynamic cross-linked polymer framework with ceramic particles to form a flexible and self-healing composite electrolyte; for sulfide-based electrolytes, an elastic polymer can be used to impregnate its voids or to form a reprocessable sulfide-polymer composite, thereby sealing cracks and improving interfacial bonding.

[0035] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0036] Example 1 (Dynamic disulfide polymer electrolyte)

[0037] 10.0 g of polytetrahydrofuran glycol (PTMG, molecular weight 2000 g / mol), 5.0 g of 1,6-hexamethylene diisocyanate (HDI), and 30 mL of N,N-dimethylacetamide were mixed and reacted at 40 °C for 1 h under nitrogen protection to generate a polyurethane prepolymer (PTMG-HDI) by reacting the terminal hydroxyl groups with HDI. Subsequently, 3.0 g of 2-hydroxyethyl disulfide (BHDS) was added as a chain extender, and the reaction was continued at 40 °C for 2 h to introduce reversible disulfide crosslinking points, resulting in a polyurethane polymer solution containing dynamic disulfide bonds, with a polymer mass of 18 g. Under stirring, 4.0 g of lithium LiFSI (polymer to lithium salt mass ratio of 4.5:1) was added to the obtained polyurethane polymer solution, and stirring was continued until completely dissolved and a transparent homogeneous solution was formed. The resulting solution was uniformly cast onto the surface of a pre-cleaned and dried polyethylene terephthalate (PET) base film, and dried at 60°C for 12 hours to remove the solvent, resulting in a self-healing solid polymer electrolyte membrane (100 μm thick).

[0038] The electrolyte membrane was punched into a 16mm diameter disc and clamped between stainless steel blocking electrodes. An AC impedance test (frequency range 1MHz~1Hz) was performed at 25°C. The ionic conductivity of the electrolyte was obtained by fitting a Nyquist plot. The results show that the self-healing solid polymer electrolyte membrane of this embodiment achieves an ionic conductivity of 2.0×10⁻⁶ at room temperature. -4 The tensile properties were tested using a universal testing machine with a sample width of 5 mm, an initial length of 20 mm, and a tensile rate of 10 mm / min. The test results showed that the tensile elongation at break of the electrolyte membrane reached 500%, indicating good flexibility. At room temperature (25℃), the electrolyte membrane was cut into strips of 10 mm × 30 mm. A 5 mm slit was completely cut along the width direction in the middle using a sharp blade. The cut surfaces were then slightly aligned and adhered together, and the membrane was left to stand at 25℃ for 10 minutes. After standing, the slits were almost completely disappeared to the naked eye. A subsequent tensile test showed that the sample did not break under a tensile stress of 0.5 MPa, indicating that the electrolyte membrane possesses good room-temperature self-healing mechanical strength.

[0039] Preparation of Li|SPAN self-healing solid-state battery: (1) Preparation of SPAN positive electrode active material: Polyacrylonitrile (PAN) and elemental sulfur are mixed at a mass ratio of 6:4. N,N-dimethylformamide (DMF) is added and stirred to form a uniform slurry. Most of the solvent is removed by stirring at 90°C to obtain precursor powder. The dried precursor powder is placed in a tube furnace and heated to 300°C at 3°C / min under a nitrogen atmosphere. After holding at the temperature for 5 hours, it is naturally cooled to room temperature. The powder is then ground and sieved to obtain sulfurized polyacrylonitrile (SPAN) powder. (2) Preparation of SPAN positive electrode sheet: SPAN powder, conductive carbon black Super P and polyvinylidene fluoride (PVDF) are mixed at a mass ratio of 8:1:1. N-methylpyrrolidone (NMP) solvent is added and ball milled for 3 hours to obtain a uniform positive electrode slurry. The slurry was evenly coated on the aluminum foil current collector, and the wet film thickness was controlled at 100 μm. It was dried in an 80℃ drying oven for 10 h to obtain a dried positive electrode sheet. Then it was compacted on a roller press to make the surface density of the SPAN active material 2.0 mg / cm². Finally, it was punched into a circular positive electrode sheet with a diameter of 14 mm for later use. (3) Preparation of negative electrode and electrolyte: The negative electrode is made of metal lithium foil with a thickness of 100 μm. It is punched into a lithium sheet with a diameter of 16 mm. The surface oxide layer is removed by lightly scraping the surface with a plastic scraper for later use. (4) The self-healing solid polymer electrolyte membrane with a thickness of 100 μm prepared in this embodiment is punched into a circular sheet with a diameter of 16 mm for later use. (5) Assembly of Li|SPAN solid battery: The CR2032 button battery is assembled in an argon-protected glove box with a water and oxygen content of less than 1 ppm. The assembly sequence is: stainless steel bottom shell / lithium foil negative electrode / self-healing solid polymer electrolyte membrane / SPAN positive electrode sheet / stainless steel gasket / spring sheet / top shell. After assembly, the battery is sealed under 10MPa pressure using a sealing machine. The resulting battery is then left to stand at room temperature for 12 hours to allow the electrode / electrolyte interface to fully contact.

[0040] Electrochemical performance testing of Li|SPAN solid-state batteries: Constant current charge-discharge tests were conducted on the above-mentioned Li|SPAN solid-state batteries at 25℃, with a voltage range of 1.5~3.0V (vs. Li / L). Based on the theoretical capacity of 1672 mAh / g using SPAN, and with 0.2C as the test rate, the test results show that the solid-state battery retains approximately 90% of its capacity after 600 cycles at 0.2C, and its coulombic efficiency remains above 99%. This indicates that the prepared self-healing solid polymer electrolyte can effectively maintain the stability of the electrode / electrolyte interface and suppress structural damage during long-term cycling.

[0041] Preparation and testing of Li|Li symmetric self-healing solid-state battery: (1) Assembly of Li|Li symmetric battery: In an argon-protected glove box, two 100μm thick and 16mm diameter lithium foils were selected as symmetric electrodes, and their surfaces were lightly scraped to expose fresh lithium surfaces. The self-healing solid polymer electrolyte membrane of this embodiment was cut into 16mm diameter discs and placed between the two lithium foils. The CR2032 coin cell was assembled in the order of "lithium sheet / self-healing solid polymer electrolyte membrane / lithium sheet / pad / spring sheet / upper shell" and sealed under 10MPa pressure. The encapsulated symmetric battery was placed at room temperature for 6h. (2) Cyclic test of symmetric battery: At 25℃, the Li|Li symmetric solid-state battery was subjected to constant current peeling / deposition test. The current density was set to 0.2mA / cm², and the single peeling / deposition time was 1h, forming a reciprocating cycle. Under the above conditions, the Li|Li symmetric solid-state battery can cycle stably for more than 6000 hours without short circuit, and the polarization voltage is basically maintained in the range of 20~50mV. This indicates that the self-healing solid polymer electrolyte and lithium metal interface are stable, which can effectively suppress lithium dendrite growth and maintain stable cycling for a long time.

[0042] This embodiment demonstrates that the polyurethane-based self-healing solid electrolyte with dynamic disulfide bond crosslinking not only has high room temperature ionic conductivity and excellent flexibility and self-healing ability, but also can significantly improve the cycle life and interface stability of Li|SPAN solid-state batteries and Li|Li symmetric batteries when assembling them.

[0043] Example 2 (Metal-ligand dynamic polymer electrolyte)

[0044] Synthesis of a pyridine-containing polyurethane (Py-PU) matrix: 8.0 g of polytetrahydrofuran diol (PTMG, molecular weight 2000 g / mol) and 6.0 g of pyridine 3-isocyanate (providing pyridine ligands) were reacted in N,N-dimethylformamide to generate a pyridine-containing polyurethane matrix (Py-PU); subsequently, ZrC was added. As a coordination crosslinking agent, the resulting polymer solution was placed under stirring, and Zr 4+ The ion forms a reversible coordination network with the pyridine ligand. This controls the ZrC... The feed amount was adjusted so that the molar ratio of Zr to pyridine was 1:4 to obtain a polymer gel. Then, lithium LiTFSI salt was added (the mass ratio of polymer gel to lithium salt was 3:1), and the mixture was cast onto a PET film and heated to 50°C for 2 hours to obtain a self-healing solid polymer electrolyte membrane (120 μm).

[0045] The solid electrolyte membrane prepared in this embodiment has an ionic conductivity of 1.0 × 10⁻⁶ at 30 °C. -3 The S / cm ratio was higher than that of the control sample without metal coordination.

[0046] Preparation process of NCM811 positive electrode / lithium negative electrode full cell: (1) Preparation of NCM811 positive electrode sheet: Commercial NCM811 powder (ternary nickel cobalt manganese oxide, Ni:Co:Mn molar ratio of 8:1:1) was used as the positive electrode active material. NCM811 powder, conductive carbon black (Super P) and polyvinylidene fluoride (PVDF) were mixed at a mass ratio of 93:5:5. N-methylpyrrolidone (NMP) was added as a solvent and stirred and dispersed in a planetary ball mill for 3 hours to obtain a uniform and fine positive electrode slurry. The above slurry was uniformly coated on an aluminum foil current collector (aluminum foil thickness 15μm), the wet film thickness was controlled at 120μm, and dried at 100℃ for 10 hours to remove the solvent and obtain a dried positive electrode sheet. The dried positive electrode sheet was compacted on a roller press at a pressure of 120 MPa to control the surface loading of active material at 10 mg / cm² (based on the mass of NCM811), corresponding to an surface capacity of 2.5 mAh / cm². It was then punched into a circular positive electrode sheet with a diameter of 15 mm for later use. (2) Preparation of self-healing solid electrolyte membrane and lithium negative electrode: The self-healing solid polymer electrolyte membrane of this embodiment was punched into a circular sheet with a diameter of 16 mm for later use. The lithium foil was used as the negative electrode. The thickness of the lithium foil was 60 μm. It was punched into a circular sheet with a diameter of 16 mm under an inert atmosphere. The surface was lightly scraped with an inert plastic scraper to remove the oxide layer and expose the fresh lithium metal surface for later use.

[0047] (3) Assembly of NCM811 / Li all-solid-state battery: In an argon-protected glove box with water and oxygen content both less than 1 ppm, the CR2032 coin cell all-solid-state battery was assembled in the following order: stainless steel bottom shell / lithium foil negative electrode / self-healing solid polymer electrolyte membrane / NCM811 positive electrode / stainless steel gasket / spring sheet / top shell. After assembly, the battery was sealed under 12 MPa pressure using a sealing machine to form an all-solid-state battery with NCM811 positive electrode / lithium negative electrode. The sealed battery was left to stand at room temperature for 18 hours to ensure sufficient contact and wetting between the electrolyte membrane and the electrode interface.

[0048] Electrochemical testing of the NCM811 cathode / lithium anode full cell: Constant current charge-discharge tests were performed on the above-mentioned NCM811 / Li all-solid-state battery at 30℃, with a voltage range of 2.8~4.3 V (vs. Li / L). Based on the theoretical capacity of NCM811, a formation cycle of 2-5 cycles was first performed at 0.1-0.2C, followed by a long-term cycle test at 3C. The test results show that the NCM811 cathode / lithium anode all-solid-state battery prepared in this embodiment exhibits less than 20% capacity decay after 500 cycles at 3C, demonstrating excellent rate performance and cycle stability. This is closely related to the stable interface and uniform lithium deposition capability provided by the metal-ligand dynamic polymer electrolyte.

[0049] Example 3 (Hydrogen Bond Self-Healing Polymer Electrolyte)

[0050] A polymer network containing urea-based dihydrogen bond units was prepared by free radical polymerization using acrylamide and a diol containing a four-fold hydrogen bond functional group (UPy group) as monomers: 20.0 g of acrylamide, 5.0 g of an acrylamide derivative containing an UPy group, and initiator AIBN were dissolved in acrylonitrile. The mixture was heated to 65 °C and copolymerized with stirring at this temperature for 6 h. After cooling to room temperature, a polymer solution containing UPy four-fold hydrogen bond units was obtained. 10.0 g of [EMIm][TFSI] ionic liquid and 2.5 g of LiTFSI were added to the polymer solution to make the mass ratio of polymer, ionic liquid, and lithium salt 6:3:1. The mixture was stirred until completely dissolved to obtain a transparent and homogeneous solution. Subsequently, the solution was cast onto a PET film and cured at 80 °C for 2 h to obtain a self-healing solid polymer electrolyte membrane containing ionic liquid.

[0051] The self-healing solid polymer electrolyte membrane prepared in this embodiment has an ionic conductivity as high as 1.4 × 10⁻⁶. -3 With a tensile elongation of up to 2000% and a tensile strength of S / cm, it can self-repair to near its original strength within 1 hour after being broken under force at 25℃.

[0052] LiFeP / Li all-solid-state batteries are prepared according to the following steps: (1) LiFeP Preparation of positive electrode: LiFeP Powder is used as the positive electrode active material, and LiFeP Powdered conductive carbon black (Super P) and polyvinylidene fluoride (PVDF) were mixed at a mass ratio of 8:1:1. N-methylpyrrolidone (NMP) was added to the mixed powder as a solvent, and the mixture was stirred and dispersed in a planetary ball mill for 3 hours to obtain a uniform and fine positive electrode slurry. This positive electrode slurry was uniformly coated onto an aluminum foil current collector (15 μm thick), with the wet film thickness controlled at 90 μm. It was then dried in an oven at 100°C for 10 hours to remove the solvent, resulting in a dried positive electrode sheet. The dried positive electrode sheet was then compacted on a roller press at a pressure of 120 MPa to allow the LiFeP... The surface loading of the active material was controlled at 3.0 mg / cm², corresponding to an surface capacity of 0.9 mAh / cm². It was then punched into a circular positive electrode sheet with a diameter of 14 mm for later use. (2) The self-healing solid polymer electrolyte membrane of this embodiment was punched into a circular sheet with a diameter of 15 mm for later use. (3) Preparation of lithium negative electrode: The negative electrode is made of lithium foil with a thickness of 60 μm. It is punched into a circular sheet with a diameter of 15 mm under an inert atmosphere. The surface of the lithium foil is lightly scraped with an inert plastic scraper to remove the surface oxide layer and expose the fresh lithium metal surface for later use. (4) LiFeP / Li-based all-solid-state battery assembly: CR2032 coin-type all-solid-state batteries were assembled in an argon-protected glove box with water and oxygen content both below 1 ppm. The assembly sequence was: stainless steel bottom shell / lithium foil anode / self-healing solid polymer electrolyte membrane / LiFeP After the positive electrode sheet, stainless steel gasket, spring sheet, and upper shell are assembled, they are sealed using a sealing machine under 12MPa pressure. The sealed battery is then left to stand at room temperature (25℃) for 18 hours to ensure that the electrolyte membrane is in full contact with and wetted at the positive and negative electrode interfaces.

[0053] LiFeP Electrochemical testing of the Li-FeP all-solid-state battery: The above-mentioned LiFeP was tested at 25°C. Constant current charge-discharge tests were conducted on the Li / L all-solid-state battery, with the voltage window set at 2.5~3.8 V (vs. Li / L). First, 2-5 formation cycles were performed at 0.1-0.2C, followed by cycle lifetime testing at a 0.2C rate. The test results show that the LiFeP prepared in this embodiment... The Li-Li all-solid-state battery exhibited a discharge capacity of 147 mAh / g after 120 cycles at 0.2C, with coulombic efficiencies exceeding 99.7%. During cycling, the voltage curve remained stable with minimal polarization, indicating that the UPy hydrogen-bonded self-healing polymer electrolyte membrane can achieve in-situ reversible repair under battery operating conditions, effectively maintaining the integrity of the electrode / electrolyte interface and the continuity of ion transport channels. This system utilizes UPy quadruple hydrogen bonds to enhance inter-polymer chain interactions, while the ionic liquid and LiTFSI reinforce the framework through electrostatic interactions, achieving in-situ reversible repair under battery operating conditions.

[0054] Example 4 (Polyionic liquid-based self-healing electrolyte)

[0055] A polymer network was prepared using polyvinyl alcohol (PVA) and 1-allyl-3-methylimidazolium tetrafluoroborate (PAM·TFSI): 10.0 g of PVA was dissolved in 90.0 g of deionized water, heated to 90 °C and kept at that temperature for 1 h until completely dissolved. The solution was then cooled to 45 °C, and 5.0 g of 1-allyl-3-methylimidazolium tetrafluoroborate (PAM·TFSI) and 3.0 g of LiCl were added. After stirring for 1 hour, a homogeneous mixed solution was obtained. 2 g of triethyl borate was added to the mixed solution as a crosslinking agent, and the reaction was continued at 50°C for another 1 hour to obtain a precursor solution for membrane fabrication. The precursor solution was cast onto a PET film and cured at 80°C for 2 hours to obtain a self-healing solid polymer electrolyte membrane with a thickness of 100 μm. This composite electrolyte membrane introduces borate ester bonds and electrostatic interactions, exhibiting swelling properties and improved ionic conductivity.

[0056] The solid electrolyte membrane prepared in this embodiment has an ionic conductivity of 0.8 × 10⁻⁶ at 30 °C. -3 S / cm; Meanwhile, due to the polyionic liquid and L Through interaction, the membrane exhibits good mechanical elasticity. At room temperature (25°C), after repeatedly bending the electrolyte membrane until visible microcracks or creases appear, and then laying the membrane flat for 10 minutes, the cracks essentially disappear, and the surface returns to a smooth state, indicating that the membrane has good room-temperature self-healing capabilities. Flexible solid-state batteries prepared using this electrolyte maintain a capacity retention of >90% after 500 bending tests, demonstrating a significantly improved cycle life.

[0057] Example 5 (Microcapsule-assisted self-healing solid electrolyte)

[0058] Microcapsules containing a repair agent are added to a composite PVDF adhesive solution for one-time self-repair. 0.8g of RbN... Microcapsules (shell is polyurea, diameter 0.8 μm) and 0.8 g PVDF binder are added to 8.0 g N-methylpyrrolidone to form a slurry, which is then coated on the surface of the self-healing solid electrolyte membrane of Example 1 and dried to obtain a solid electrolyte membrane coated with a microcapsule layer (microcapsule layer thickness 3 μm).

[0059] In this embodiment, the solid electrolyte, during the first charge-discharge process of the battery, triggers the microcapsule rupture by heating the battery to 70°C, releasing RbNO3 and causing R... A charge-shielding layer was formed on the lithium dendrite surface, and a Li3N-rich solid electrolyte interphase (SEI) film was generated. Results showed that the battery's symmetric impedance decreased after heat treatment, and dendrite growth was significantly suppressed during cycling. The microencapsulation method only provides a single-release repair, but it is highly effective for lithium metal dendrite protection and initial electrode interface adjustment.

[0060] Example 6 (Oxide ceramic-polymer composite self-healing electrolyte)

[0061] High-melting-point composite electrolytes were prepared using the approach of plastic-ceramic electrolytes: 50g of Li... 1.3 Al 0.3 Ti 1.7(PO4)3 (LATP) powder was mixed with 50g of a self-healing polymer precursor (the self-healing polymer precursor was a cross-linked acrylate prepolymer obtained by partial polymerization of ethyl acrylate (EA), 2-hydroxyethyl acrylate (HEA), and polyethylene glycol diacrylate (PEGDA, number average molecular weight 500) in a mass ratio of 50:20:30 under AIBN initiation to prepare a uniform composite powder by cold milling. The composite powder was loaded into a mold with a diameter of 15mm and cold-pressed under a pressure of 200MPa to obtain a composite electrolyte green body with a thickness of 0.35mm. Cracks were opened at room temperature, and then the composite was pressed flat. The polymer matrix sealed the cracks during the curing process. In this embodiment, the self-healing polymer precursor is a partially polymerized acrylate prepolymer, which retains the flowability of chain segments and unreacted double bonds during the subsequent heating and curing process. It can flow, wet, and further cross-link in the crack area, thereby achieving one-time self-healing of the crack.

[0062] The composite electrolyte in this embodiment has an ionic conductivity of 0.8 mS / cm at 1 MHz and an applied voltage of 0.2 mA / cm. 2 After one year of current cycling, X-ray fluorescence detection of the cracked area showed that the crack had been filled by dynamic polymer, and the Li metal symmetric cell continued to output a stable voltage for more than 2000 hours.

[0063] The embodiments 1 to 6 of the present invention can be combined and applied to different scenarios: for power batteries that focus on high cycle life and safety, embodiments 1, 2 or 6 can be used to obtain high conductivity and interface stability; for wearable scenarios, embodiments 3 or 4 can be used to obtain excellent flexibility and multiple self-healing functions.

[0064] This invention combines various self-healing chemical bonds (dynamic covalent bonds, metal-ligand coordination bonds, ionic bonds, hydrogen bonds, etc.) with solid-state electrolyte systems, proposing multiple self-healing technical pathways that are significantly superior to existing single mechanisms. Simultaneously, this invention proposes an integrated electrode / electrolyte fabrication process (such as directly casting polymer electrolytes onto the electrodes) to obtain a highly efficient self-healing interface. Furthermore, based on the needs of power batteries and wearable applications, various material systems and fabrication processes have been designed, providing a new technical route for next-generation high-safety, long-life solid-state batteries. The self-healing solid-state electrolyte of this invention improves the self-healing capabilities of oxide, sulfide, and composite solid-state electrolyte layers in solid-state batteries, solving the problems of microcracks generated during cycling, leading to interrupted ion transport or electrode-electrolyte interface delamination; it also meets the different needs of power batteries (such as electric vehicle power batteries) and wearable devices (frequent bending and impact).

[0065] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A self-healing solid electrolyte, characterized in that, The self-healing solid electrolyte comprises a self-healing polymer matrix, a lithium salt, and a dynamically rearrangeable chemical bond structure; the self-healing polymer matrix contains dynamic chemical bonds, which include one or more of reversible covalent bonds, metal-ligand coordination bonds, hydrogen bonds, and ionic bonds; The reversible covalent bonds include disulfide bonds or acylhydrazone bonds, and the hydrogen bonds include multiple hydrogen bonds.

2. The self-healing solid electrolyte according to claim 1, characterized in that, The metal-ligand coordination bond is a coordination bond network formed by the metal ion and the ligand.

3. The self-healing solid electrolyte according to claim 2, characterized in that, The metal ions include Zr. 4+ Cu 2+ and Zn 2+ One or more of them, the ligands of which include pyridine or carboxylates.

4. The self-healing solid electrolyte according to claim 3, characterized in that, The polymer matrix in the self-healing polymer matrix includes polyurethane, polyamide, polycarbonate, polyethylene glycol block copolymer or polyionic liquid; the lithium salt includes LiFSI, LiTFSI, LiClO4 or LiPF6.

5. The method for preparing the self-healing solid electrolyte according to any one of claims 1 to 4, characterized in that, It includes the following steps: Polymer precursors and chain extenders are polymerized in a solvent to form a polymer network with reversible bonds; lithium salts are added to the polymer network to obtain a self-healing solid electrolyte.

6. The preparation method according to claim 5, characterized in that, The polymer precursor comprises polyether and / or polyol, and the chain extender is a compound containing disulfide groups or carbon-carbon double bonds; the mass ratio of polymer network to lithium salt is 1~10:1; the polymerization reaction temperature is 40~60℃.

7. A self-healing solid-state battery, characterized in that, The self-healing solid-state battery comprises a positive electrode material, a negative electrode material, and a self-healing solid electrolyte membrane formed by curing the self-healing solid electrolyte as described in any one of claims 1 to 4. The positive electrode material comprises a sulfide, a high-voltage oxide, or an air electrode, and the sulfide comprises L... S or sulfurized polyacrylonitrile, high-voltage oxide includes nickel cobalt manganese oxide or lithium iron phosphate composite oxide, and the negative electrode material is lithium or silicon. The curing temperature is 50~100℃, and the curing time is 1~24h.

8. The self-healing solid-state battery according to claim 7, characterized in that, The surface of a self-healing solid electrolyte membrane or electrode is coated with a microcapsule layer. The shell of the microcapsule is made of formaldehyde-urea-phenolic resin or polyurea, and the core material of the microcapsule is a repair agent containing RbN. One or more of the following: solution, polymerizable monomer, and liquid metal, RbN The concentration of the solution is 0.5~2.0 mol / L; the thickness of the coating is 1~5 μm.

9. The method for preparing the self-healing solid-state battery according to claim 7 or 8, characterized in that, The process includes the following steps: casting or coating a self-healing solid electrolyte onto a thin film surface and then curing it to form a self-healing solid electrolyte membrane; assembling the self-healing solid electrolyte membrane with positive electrode materials and negative electrode materials to form a self-healing solid battery, thereby achieving self-healing connection at the electrode / electrolyte interface. The self-healing solid electrolyte is a self-healing solid electrolyte solution or a self-healing solid electrolyte slurry, and the thin film is a positive electrode thin film or a negative electrode thin film.

10. The application of the self-healing solid-state battery according to claim 7 or 8 in power batteries or wearable devices.