A self-healing halide composite solid-state electrolyte film based on yttrium coordination cross-linking and a preparation method thereof
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CENT SOUTH UNIV
- Filing Date
- 2026-03-27
- Publication Date
- 2026-06-19
Smart Images
Figure CN122246233A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of all-solid-state lithium battery materials, and relates to a solid electrolyte material, specifically a yttrium-doped halide composite solid electrolyte membrane and its preparation method and application. Background Technology
[0002] With the rapid development of the new energy industry, traditional liquid lithium-ion batteries, due to limitations in energy density, electrolyte leakage, and insufficient cycle stability, are no longer able to meet the urgent needs of electric vehicles, portable electronic devices, and large-scale energy storage for high-performance energy storage devices. All-solid-state lithium-ion batteries, which replace traditional liquid electrolytes with solid electrolytes, have become a core research and development direction for next-generation energy storage technology due to their high energy density, excellent safety, and long cycle life, attracting widespread attention from the global scientific and industrial communities.
[0003] Solid-state electrolytes are the core component of all-solid-state lithium-ion batteries, and their performance directly determines the overall performance of the battery. Among them, halide solid-state electrolytes (such as Li3InCl6) are gradually emerging due to their high ionic conductivity, good machinability, and chemical compatibility with high-voltage cathode materials (such as NCM811). However, in practical applications, in order to meet the winding requirements of pouch batteries, powder materials must be prepared into flexible thin films.
[0004] Existing wet coating film-forming technologies face a severe "solvent-binder" matching challenge: halide electrolytes are strong Lewis acidic ionic crystals, which readily undergo complexation reactions with the strongly polar solvents (such as NMP and DMF) used in conventional lithium battery processes, leading to dissolution, crystal structure collapse, and a drastic decrease in ionic conductivity. To avoid dissolution, existing technologies are forced to use weakly polar solvents (such as toluene), which prevents the use of high-performance polyvinylidene fluoride (PVDF) as a binder, forcing the use of rubber-based binders with poor oxidation resistance, severely limiting the high-voltage cycle performance of the battery. Furthermore, in existing composite films, the inorganic particles and polymers are only physically mixed, lacking chemical bonding, resulting in easily peeled interfaces and a lack of self-healing capabilities. Summary of the Invention
[0005] In view of the defects and deficiencies of the existing technology, the present invention provides, in a first aspect, a self-healing halide composite solid electrolyte membrane with an in-situ coordination crosslinking structure; in a second aspect, a method for preparing the composite solid electrolyte membrane; and in a third aspect, an all-solid-state battery comprising the composite solid electrolyte membrane.
[0006] In a first aspect, the present invention provides a self-healing halide composite solid electrolyte membrane having an in-situ coordination crosslinking structure, comprising an inorganic active filler and a polymer matrix.
[0007] The inorganic active filler is a yttrium (Y) doped halide electrolyte with the chemical formula Li3In. 1-x Y x Cl6, where 0.05 ≤ x ≤ 0.4;
[0008] The polymer matrix is a modified fluoropolymer with polar coordinating groups in the side chains;
[0009] In this process, the Y ions on the surface of the inorganic active filler form chemical coordination bonds with the polar coordinating groups of the polymer matrix.
[0010] Preferably, the inorganic active filler particles exhibit a Y-rich phase distribution on their surface and are in a coordinated unsaturated activated state.
[0011] Preferably, the modified fluoropolymer is any one or more of carboxylated polyvinylidene fluoride (PVDF-COOH), hydroxylated polyvinylidene fluoride (PVDF-OH), or modified poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP).
[0012] Preferably, the room temperature ionic conductivity of the composite solid electrolyte membrane is 1.0 × 10⁻⁶. -3 ~ 1.5×10 -3 S / cm.
[0013] Preferably, the composite solid electrolyte membrane has a thickness of 60~100 μm and possesses self-supporting properties.
[0014] Secondly, the present invention provides a method for preparing the composite solid electrolyte membrane, comprising the following steps:
[0015] Step 1: Weigh lithium source, indium source, yttrium source and chlorine source according to stoichiometric ratio, mix them and then perform high-energy ball milling and vacuum annealing to obtain Y-doped halide precursor powder;
[0016] Step 2: Prepare a binary mixed solvent and dissolve the modified fluoropolymer in it to obtain a glue solution; the binary mixed solvent consists of a main solvent and a co-solvent;
[0017] Step 3: Disperse the powder obtained in Step 1 into the adhesive solution in Step 2, and carry out sealed stirring and aging under heating conditions to induce in-situ crosslinking reaction and obtain composite slurry;
[0018] Step 4: Apply the composite slurry to the substrate, dry and peel it off to obtain the final product.
[0019] Preferably, in step 2, the main solvent is anhydrous ethyl acetate, and the co-solvent is anhydrous acetonitrile; the volume percentage of anhydrous acetonitrile in the binary mixed solvent is 1% to 8%.
[0020] Preferably, in step 3, the temperature of the sealed stirring aging is 45~55℃, and the time is 6~12 hours.
[0021] Preferably, in step 1, the vacuum annealing temperature is 300~400℃ and the time is 4~8 hours.
[0022] Thirdly, the present invention provides an all-solid-state battery, comprising a positive electrode, a negative electrode, and a self-healing halide composite solid electrolyte membrane having an in-situ coordination crosslinking structure located between the positive electrode and the negative electrode.
[0023] Preferably, the positive electrode comprises a high-nickel ternary positive electrode material, specifically LiNi. 0.8 Co 0.1 Mn 0.1 O2 (NCM811).
[0024] Preferably, the negative electrode is selected from lithium-indium alloy (Li-In).
[0025] Preferably, the all-solid-state battery is a mold battery, and the stacking pressure applied during assembly is 50~80 MPa.
[0026] Compared with the prior art, one or more technical solutions provided by the present invention have at least one of the following beneficial effects:
[0027] (1) A dynamic self-healing network based on “Y coordination bond” was constructed, which solved the problem of mechanical brittleness and interface failure of halide film.
[0028] This invention utilizes the thermodynamic segregation effect of large-radius yttrium (Y) ions on the surface of Li3InCl6 crystals, making them highly active "chemical anchors" to form a stable coordination cross-linking structure with polar groups (-COOH / -F) on modified fluorinated polymer chains. This atomic-level "inorganic-organic interpenetrating network" not only endows the electrolyte membrane with excellent flexibility, but more importantly, it endows it with thermally driven self-healing capabilities. When microcracks are generated in the electrolyte layer due to battery charging and discharging stress, the coordination bonds can undergo reversible recombination driven by the heat generated during battery operation, achieving autonomous crack healing.
[0029] (2) A dedicated “non-good solvent” film-forming system was developed, overcoming the process bottleneck of wet coating of halide electrolytes.
[0030] Addressing the industry pain point that halide electrolytes are easily dissolved and destroyed by highly polar solvents (NMP, DMF), this invention innovatively employs a binary solvent system consisting of anhydrous ethyl acetate as the main component and trace amounts of acetonitrile as an auxiliary component. Ethyl acetate, as a poor solvent, completely preserves the crystal framework, while the trace amounts of acetonitrile act as a "surface activator," performing controlled micro-etching only on the particle surface to expose Y sites. This process achieves, for the first time, large-scale wet coating of halide electrolytes while maintaining high ionic conductivity.
[0031] (3) In-situ interface passivation and high-voltage adaptation are achieved, significantly improving the cycle life of the all-solid-state battery. The fluoropolymer matrix of this invention preferentially undergoes sacrificial decomposition on the negative electrode interface side, generating a dense and electronically insulating LiF-rich solid electrolyte interphase (SEI) in situ. This physically blocks the contact between the internal Li3InCl6 and metallic lithium, effectively suppressing the reduction side reaction of In. At the same time, this composite film combines the antioxidant properties of halides with the elastic buffering effect of polymers, enabling stable adaptation to the high voltage operation of NCM811 cathode above 4.3V, and effectively suppressing the pulverization of cathode particles. Attached Figure Description
[0032] Figure 1 The Li obtained in step 2 of Example 1 3.0 In 0.8 Y 0.2 SEM image of Cl6 solid electrolyte
[0033] Figure 2 The Li obtained in step 2 of Example 1 3.0 In 0.8 Y 0.2 XRD pattern of Cl6 solid electrolyte
[0034] Figure 3 The above are charge-discharge test diagrams of the all-solid-state batteries prepared in Example 1 and Comparative Examples 1, 2, and 4.
[0035] Figure 4 Impedance diagrams of all-solid-state batteries prepared in Example 1, Comparative Examples 1, 2, and 4. Detailed Implementation
[0036] The present invention provides the following specific technical solutions.
[0037] In a first aspect, the present invention provides a yttrium-doped halide solid electrolyte material with the chemical formula Li3In. 1-x Y x Cl6, where 0.05 ≤ x ≤ 0.4.
[0038] The inventors discovered through research that doping solid electrolyte materials with an appropriate amount of yttrium has a dual modification effect: (1) Bulk phase modification: the radius of yttrium ions (0.90 Å) is greater than that of indium ions (0.80 Å), Y 3+ Replace part In 3+ It can expand the lattice volume, reduce the lithium-ion migration energy barrier, and improve the room temperature ionic conductivity. (2) Surface modification: Due to the thermodynamic compression effect caused by the difference in ionic radius, some Y 3+ It spontaneously segregates towards the crystal surface, forming a high concentration of active Y sites on the particle surface. These sites are in a coordination unsaturated state, providing the necessary "chemical anchors" for subsequent chemical cross-linking with the polymer matrix, thus solving the problem of weak bonding at the interface between traditional halides and polymers. Preferably, the yttrium-doped halide solid electrolyte material particles are in an irregular block shape.
[0039] Preferably, the room temperature ionic conductivity of the yttrium-doped halide solid electrolyte material is 1.0 × 10⁻⁶. -3 ~1.5×10 -3 S / cm.
[0040] Secondly, the present invention provides a method for preparing a yttrium-doped halide solid electrolyte material, comprising the following steps:
[0041] Step 1: Lithium chloride, indium chloride and yttrium chloride are ball-milled and mixed under a protective atmosphere to obtain a precursor mixed powder;
[0042] Step 2: Sinter the precursor mixture powder under a protective atmosphere or vacuum, cool it, and then grind it to obtain the final product.
[0043] Through research, the inventors discovered that the preparation method provided by this invention is carried out entirely in an inert atmosphere, with the sintering temperature controlled at 300~400℃. This ensures that yttrium ions stably occupy lattice sites and induces appropriate surface segregation, balancing ionic conductivity and structural stability. If the temperature is too high, it will lead to excessive aggregation of Y ions, forming impurity phases; if the temperature is too low, the doping will be uneven.
[0044] Preferably, in step 1, the ratio of the mass of the milling media to the total mass of the raw materials is (20~40):1, the milling speed is 400~600 rpm, and the milling time is 12~18 h. Preferably, in step 2, the sintering temperature is 300~400℃, and the sintering time is 4~8 h.
[0045] Thirdly, the present invention provides a self-healing composite solid electrolyte membrane with a coordination crosslinking structure, comprising the above-mentioned yttrium-doped halide solid electrolyte material and a modified fluoropolymer matrix.
[0046] The inventors discovered through research that existing halide composite membranes generally suffer from high mechanical brittleness, are prone to cracking under stress, and are irreparable. In this invention, modified PVDF with polar groups (such as -COOH) on its side chains is selected, utilizing the Yg enriched on the surface of inorganic particles... 3+ It forms YO coordination bonds with carboxyl groups on the polymer chain. This atomic-level "inorganic-organic interpenetrating network" has the following advantages:
[0047] (1) Self-repair function: When microcracks are generated in the electrolyte membrane, the coordination bonds can undergo reversible recombination under the heat generated during battery operation (about 50°C), thereby achieving crack healing;
[0048] (2) Resistance to solvents: The specific cross-linking structure enhances the material's resistance to solvents;
[0049] (3) Interface protection: The LiF interface layer generated in situ on the negative electrode side by the fluoropolymer can effectively suppress In 3+ The restoration.
[0050] Preferably, the mass ratio of the yttrium-doped solid electrolyte material to the modified fluoropolymer is 80:20 to 95:5.
[0051] Preferably, the composite solid electrolyte membrane has a thickness of 60~100 μm and possesses self-supporting properties.
[0052] Fourthly, the present invention provides a method for preparing a composite solid electrolyte membrane, comprising the following steps:
[0053] Step 1: Prepare a binary mixed solvent consisting of a main solvent and a co-solvent, and dissolve the modified fluoropolymer in it;
[0054] Step 2: Disperse the yttrium-doped solid electrolyte powder in the colloid solution, and perform sealed stirring and aging under heating conditions to induce in-situ crosslinking;
[0055] Step 3: Apply, dry, and peel off.
[0056] The inventors discovered through research that the choice of solvent system is crucial to the success of film formation. Conventional strongly polar solvents (such as NMP) can damage halide crystals. This invention employs anhydrous ethyl acetate (main solvent) + a trace amount of anhydrous acetonitrile (co-solvent). Ethyl acetate protects the crystal framework from dissolution; the trace amount of acetonitrile (<5%) acts as a "surface etchant," exposing surface Y ions and promoting their contact with the polymer chains. Simultaneously, a 45-55℃ aging process provides the thermal activation energy required for the coordination reaction, ensuring high-strength chemical crosslinking.
[0057] Fifthly, the present invention provides an all-solid-state battery, comprising a positive electrode, a negative electrode, and the aforementioned composite solid-state electrolyte membrane located between the positive and negative electrodes. Preferably, the positive electrode comprises a high-nickel ternary positive electrode material (NCM811). Preferably, the negative electrode is a lithium-indium alloy (Li-In) or metallic lithium.
[0058] Preferably, the all-solid-state battery is a mold battery, and the stacking pressure applied during assembly is 50~80 MPa.
[0059] To make the technical problems, technical solutions and technical advantages of the present invention clearer, a detailed description will be given below with reference to specific examples. However, the scope of protection of the present invention is not limited to the following specific embodiments.
[0060] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.
[0061] Example 1 (Intermediate values of preferred parameters / best embodiment):
[0062] A method for preparing a self-healing composite solid electrolyte membrane with an in-situ coordination crosslinking structure and an all-solid-state battery includes the following steps:
[0063] Step 1: Weigh anhydrous lithium chloride (LiCl), indium chloride (InCl3), and yttrium chloride (YCl3) under an argon atmosphere. The purity of all raw materials must be ≥99%. According to the chemical formula Li3In... 0.8 Y 0.2 Based on the stoichiometric ratio of Cl6 (x=0.2), weigh out 0.385g of LiCl, 0.536g of InCl3, and 0.118g of YCl3. Add the above raw materials to a mortar and mix manually for 10 minutes. Then, add zirconia grinding beads at a mass ratio of 30:1 and ball mill at 500 rpm for 12 hours under an inert atmosphere (argon) to obtain a homogeneous precursor mixture.
[0064] Step 2: The precursor mixture is loaded into a quartz tube, sealed under vacuum in an argon atmosphere, and then sintered in a muffle furnace at 350°C for 5 hours, then cooled to room temperature. The sintered product is then ground into a fine powder in an argon atmosphere to obtain Y-doped halide powder.
[0065] Step 3: Prepare a binary mixed solvent of anhydrous ethyl acetate and anhydrous acetonitrile in a ratio of 95:5 (volume ratio). Dissolve the modified polymer carboxylated polyvinylidene fluoride (PVDF-COOH) in this solvent to prepare a polymer solution with a solid content of 5 wt%.
[0066] Step 4: Mix the Y-doped halide powder obtained in Step 2 with the polymer solution obtained in Step 3, with a mass ratio of inorganic powder to polymer of 90:10. Place the mixture in a sealed container and stir and age it for 8 hours in a 50°C water bath to induce an in-situ coordination crosslinking reaction.
[0067] Step 5: Apply the aged slurry to the Teflon substrate surface, allow it to air dry at room temperature, and then dry it in an 80℃ vacuum oven for 24 hours. Peel off the slurry to obtain a self-supporting composite solid electrolyte membrane with a thickness of 80μm. Subsequently, use a cutting machine to cut the composite solid electrolyte membrane into circular pieces with a diameter of 10mm and place them in an argon glove box for later use.
[0068] Step 6: In an argon-filled glove box, assemble the stainless steel mold battery. Place the stainless steel column at the bottom of the mold cavity as the lower current collector, then sequentially place the lithium indium alloy (Li-In) negative electrode sheet, the composite solid electrolyte membrane cut in Step 5, and then the NCM811 positive electrode disc. Next, place the stainless steel column as the upper current collector, and finally place the mold battery in the stainless steel frame. Use a torque wrench to tighten the bolts to apply pressure, controlling the battery stacking pressure to 50~80 MPa, thus obtaining the all-solid-state mold battery.
[0069] Example 2 (lower value boundary of preferred range):
[0070] A method for preparing an all-solid-state battery includes the following steps:
[0071] Step 1, according to the chemical formula Li3In 0.95 Y 0.05 The raw materials were weighed according to the stoichiometric ratio of Cl6 (x=0.05). The ball milling process was the same as in Example 1.
[0072] Step 2: Set the sintering temperature to 300℃ and hold for 4 hours. The rest is the same as in Example 1.
[0073] Step 3 is the same as in Example 1.
[0074] Step 4: Place the mixed slurry in a sealed container and stir and age it for 12 hours in a 45°C water bath.
[0075] Steps 5 and 6 are the same as in Example 1.
[0076] Example 3 (High value boundary of preferred range):
[0077] A method for preparing an all-solid-state battery includes the following steps:
[0078] Step 1, according to the chemical formula Li3In 0.6 Y 0.4The raw materials were weighed according to the stoichiometric ratio of Cl6 (x=0.4). The ball milling process was the same as in Example 1.
[0079] Step 2: Set the sintering temperature to 400℃ and hold for 8 hours. The rest is the same as in Example 1.
[0080] Step 3 is the same as in Example 1.
[0081] Step 4: Place the mixed slurry in a sealed container and stir and age it for 6 hours in a 55°C water bath.
[0082] Steps 5 and 6 are the same as in Example 1.
[0083] Example 4 (Changes in solvent ratio): A method for preparing an all-solid-state battery, comprising the following steps:
[0084] Steps 1 and 2 are the same as in Example 1.
[0085] Step 3: Prepare a binary mixed solvent of anhydrous ethyl acetate and anhydrous acetonitrile in a ratio of 98:2 (volume ratio). Dissolve PVDF-COOH in the solvent.
[0086] Comparative Example 1: (The difference from Example 1 is that yttrium chloride was not added (no Y doping), while other parameters remained the same.)
[0087] A method for preparing an all-solid-state battery includes the following steps:
[0088] Step 1: Without adding yttrium chloride (YCl3), only weigh lithium chloride and indium chloride, and prepare them according to the chemical formula Li3InCl6. All other ball milling parameters are exactly the same as in Example 1.
[0089] Step 2: Maintain the sintering temperature at 350℃ for 5 hours. This is completely consistent with Example 1.
[0090] Step 3, same as in Example 1 (using PVDF-COOH and ethyl acetate / acetonitrile solvent).
[0091] Step 4: Maintain the aging temperature at 50°C and the aging time at 8 hours. This is completely consistent with Example 1.
[0092] (Note: Strict control of a single variable proves that even with COOH and aging processes, high performance cannot be achieved without the Y element.)
[0093] Steps 5 and 6 are the same as in Example 1.
[0094] Comparative Example 2: (The difference from Example 1 is that the polymer matrix was not modified (no functional groups), while other parameters remained the same) A method for preparing an all-solid-state battery, comprising the following steps:
[0095] Steps 1 and 2 are the same as in Example 1 (with Y doping maintained).
[0096] Step 3: Replace PVDF-COOH with ordinary polyvinylidene fluoride (PVDF, without -COOH side chains). Maintain the solvent system as ethyl acetate: anhydrous acetonitrile = 95:5.
[0097] Step 4: Maintain the aging temperature at 50°C and the aging time at 8 hours. This is completely consistent with Example 1.
[0098] Steps 5 and 6 are the same as in Example 1.
[0099] Comparative Example 3: (The difference from Example 1 is that the solvent system is different (NMP is used), while other parameters remain the same) A method for preparing an all-solid-state battery includes the following steps:
[0100] Steps 1 and 2 are the same as in Example 1.
[0101] Step 3: N-methylpyrrolidone (NMP) is used as the sole solvent, without adding ethyl acetate or acetonitrile. PVDF-COOH is dissolved in it. Step 4: The aging temperature is maintained at 50°C, and the aging time is maintained at 8 hours. This is completely consistent with Example 1.
[0102] Steps 5 and 6 are the same as in Example 1.
[0103] Comparative Example 4: (The difference from Example 1 is that no thermal aging process was performed, but other parameters remained the same.)
[0104] A method for preparing an all-solid-state battery includes the following steps:
[0105] Steps 1 to 3 are the same as in Example 1.
[0106] Step 4: After adding the powder to the adhesive, mix directly at room temperature for 30 minutes before coating, skipping the 50℃ heating and aging step.
[0107] Steps 5 and 6 are the same as in Example 1.
[0108] Performance testing and characterization:
[0109] Ionic conductivity testing: The prepared solid electrolyte membrane was cut into circular pieces, and gold was sputtered on both sides or sandwiched between two stainless steel sheets as blocking electrodes to assemble a symmetrical cell. Electrochemical impedance spectroscopy (EIS) was performed using an electrochemical workstation, with a frequency range of 1 MHz to 0.1 Hz and an amplitude of 10 mV. The room temperature ionic conductivity was calculated using the formula s = L / (R × S) (where L is the membrane thickness, S is the electrode area, and R is the bulk resistance).
[0110] Self-healing performance test: The solid electrolyte membrane was placed under a microscope, and a penetrating scratch with a width of approximately 15 mm was artificially created on the membrane surface using a scalpel blade. Its ionic conductivity was then measured (denoted as s0). Subsequently, the damaged membrane was heat-treated in a 50℃ constant temperature oven for 2 hours, and its ionic conductivity was measured again (denoted as s1). Conductivity recovery rate (%) = (s1 / s0) × 100%.
[0111] Test results: The ionic conductivity of the solid electrolyte membranes prepared in Examples 1-4 and Comparative Examples 1-4 at room temperature was tested using AC impedance spectroscopy, and the conductivity recovery rate after artificial folding / scratching and heat treatment at 50℃ was also tested (characterizing self-healing performance). The test data are shown in Table 1.
[0112] Table 1 Performance test data of the examples and comparative examples
[0113] sample Key variable descriptions Room temperature ionic conductivity (S / cm) Conductivity retention rate after thermal repair of scratches (%) Example 1 The preferred parameter median (Y=0.2) <![CDATA[1.25×10 -3 ]]> 96.5% Example 2 Lower limit of parameter (Y=0.05) <![CDATA[1.02×10 -3 ]]> 89.8% Example 3 Upper limit of parameters (Y=0.4) <![CDATA[1.12×10 -3 ]]> 93.4% Example 4 Low solvent and additive content (ACN=2%) <![CDATA[1.15×10 -3 ]]> 91.0% Comparative Example 1 Y-free <![CDATA[0.72×10 -3 ]]> < 10% (Unrepairable) Comparative Example 2 No functional groups (normal PVDF) <![CDATA[0.85×10 -3 ]]> < 20% Comparative Example 3 The solvent is NMP <![CDATA[< 10⁻ 6 (Material failure) / Comparative Example 4 Heatless aging process <![CDATA[0.95×10 -3 ]]> 65.3%
[0114] As shown in Table 1:
[0115] Examples 1-3 demonstrate that, within the preferred Y doping range (0.05~0.4) and process parameter range of this invention, the solid electrolyte membrane can maintain excellent ionic conductivity and self-healing performance.
[0116] Compared with Example 1, Comparative Example 1 only removed the Y element, which caused the material to lose its self-healing ability and its electrical conductivity to decrease, proving that the Y element is the key core for constructing coordination crosslinking sites.
[0117] Compared with Example 1, Comparative Example 2 showed a decrease in performance simply by changing the polymer type, proving that the “Y-COOH” chemical bonding is the basis for achieving interface stability.
[0118] Comparative Example 3 demonstrates the destructive effect of conventional strongly polar solvents on halide materials.
[0119] Comparative Example 4 demonstrates the necessity of a specific "thermal-induced aging" process for forming a complete cross-linked network.
[0120] Figure 1 is a SEM image of the yttrium-doped halide solid electrolyte (Li3In0.8Y0.2Cl6) prepared in step 2 of Example 1. As can be seen from Figure 1, the prepared solid electrolyte particles exhibit a well-dispersed, irregular blocky morphology.
[0121] Figure 2 shows the XRD pattern of the yttrium-doped halide solid electrolyte prepared in Example 1. As can be seen from Figure 2, the diffraction peaks of the sample are sharp and match well with the standard crystal structure. No obvious impurity phase peaks are observed, indicating that the doping of yttrium (Y) element did not destroy the main crystal lattice structure of Li3InCl6, and a high-purity solid electrolyte phase was successfully prepared.
[0122] Figure 3 shows the first charge-discharge test results of the all-solid-state batteries prepared in Example 1, Comparative Example 1, Comparative Example 2, and Comparative Example 4. The test temperature was 30°C, the test rate was 0.1C, and the voltage range was 2.0~3.68V. As can be seen from Figure 3, Example 1 exhibits the highest specific capacity (close to 200 mAh / g), a clear and stable voltage plateau, and the smallest charge-discharge voltage difference (polarization), demonstrating the best electrochemical performance.
[0123] Figure 4 shows a comparison of the AC impedance spectra (EIS) of the all-solid-state batteries prepared in Example 1, Comparative Example 1, Comparative Example 2, and Comparative Example 4. As can be seen from Figure 4, the impedance spectrum of Example 1 has the smallest semicircular diameter, indicating that its charge transfer resistance (Rct) is the lowest; while that of Comparative Example 1 has the largest impedance.
[0124] A detailed comparative analysis is conducted using Figures 3 and 4:
[0125] Comparing Example 1 and Comparative Example 1 (without Y doping), as shown in Figures 3 and 4, the discharge capacity of Comparative Example 1 is significantly reduced, and the impedance is greatly increased (black curve in Figure 4). This is because Comparative Example 1 is not doped with Y, which results in low bulk ionic conductivity of the material. Furthermore, the lack of Y ions as "chemical anchors" prevents coordination cross-linking with the polymer matrix, leading to extremely high interfacial contact impedance and severe battery polarization.
[0126] Comparative analysis was performed on Example 1 and Comparative Example 2 (ordinary PVDF, without functional groups). The charge-discharge curves of Comparative Example 2 ( Figure 3 The polarization (medium-dark gray line) is significantly greater than in Example 1, and the impedance is higher ( Figure 4 (Green curve in the middle). This is because although Comparative Example 2 has Y doping, the polymer matrix used lacks polar coordinating groups (-COOH), which cannot induce the formation of "Y-coordination bonds". Physical mixing alone cannot construct a low-impedance interfacial channel.
[0127] Comparative analysis of Example 1 and Comparative Example 4 (without thermal aging process) showed that the performance of Comparative Example 4 was inferior to that of Example 1. This is because Comparative Example 4 omitted the thermal aging step, resulting in insufficient coordination reaction kinetics and failure to form a complete "inorganic-organic interpenetrating network," which led to a reduction in both interface stability and ion transport efficiency.
[0128] The above-described embodiments are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the technical scope of the present invention, based on the technical solution and concept of the present invention, should be covered within the scope of protection of the present invention.
Claims
1. A self-healing halide composite solid electrolyte membrane with an in-situ coordinated crosslinking structure, characterized in that, It includes an inorganic active filler and a polymer matrix; the inorganic active filler is a yttrium (Y)-doped halide electrolyte with the chemical formula Li3In. 1-x Y x Cl6, wherein 0.05≤x≤0.4; the polymer matrix is a modified fluoropolymer with polar coordinating groups in the side chains; the Y ions on the surface of the inorganic active filler form chemical coordination bonds with the polar coordinating groups of the polymer matrix.
2. The self-healing halide composite solid electrolyte membrane with an in-situ coordinated crosslinking structure as described in claim 1, characterized in that, The composite solid electrolyte membrane has a room temperature ionic conductivity of 1.0 × 10⁻⁶. -3 ~ 1.5×10 -3 S / cm; the thickness of the composite solid electrolyte membrane is 60~100 μm and it has self-supporting properties.
3. The self-healing halide composite solid electrolyte membrane with an in-situ coordination crosslinking structure as described in claim 1, characterized in that, The modified fluoropolymer is any one or more of carboxylated polyvinylidene fluoride (PVDF-COOH), hydroxylated polyvinylidene fluoride (PVDF-OH), or modified poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP); the mass ratio of the yttrium-doped halide electrolyte to the modified fluoropolymer is 80:20 to 95:
5.
4. A method for preparing a self-healing halide composite solid electrolyte membrane with an in-situ coordinated crosslinking structure as described in any one of claims 1 to 3, characterized in that, The process includes the following steps: Step 1, ball milling lithium chloride, indium chloride, and yttrium chloride under a protective atmosphere to obtain a precursor mixed powder; sintering the precursor mixed powder under a protective atmosphere or vacuum, cooling, and then grinding to obtain yttrium-doped halide solid electrolyte powder; Step 2, preparing a binary mixed solvent and dissolving the modified fluoropolymer in it to obtain a colloid; Step 3, dispersing the powder obtained in Step 1 in the colloid of Step 2, and performing sealed stirring and aging under heating conditions to induce an in-situ crosslinking reaction to obtain a composite slurry; Step 4, coating the composite slurry onto a substrate, drying, and peeling to obtain the final product.
5. The preparation method according to claim 4, characterized in that, In step 1, the molar ratio of lithium in lithium chloride, indium in indium chloride, and yttrium in yttrium chloride is relative to the chemical formula Li3In. 1-x Y x The stoichiometric ratio of Cl6 is consistent; during ball milling, the ratio of the mass of the ball milling media to the total mass of the raw materials is (20~40):1, the ball milling speed is 400~600 rpm, the ball milling time is 12~18 h, the sintering temperature is 300~400℃, and the sintering time is 4~8 h.
6. The preparation method according to claim 4, characterized in that, In step 2, the binary mixed solvent consists of a main solvent and a co-solvent. The main solvent is anhydrous ethyl acetate, and the co-solvent is anhydrous acetonitrile. The volume percentage of anhydrous acetonitrile in the binary mixed solvent is 1% to 8%.
7. The preparation method according to claim 4, characterized in that, In step 3, the temperature for the sealed stirring aging is 45~55℃, and the time is 6~12 h.
8. The preparation method according to claim 4, characterized in that, In step 4, the drying temperature is 80℃ and the vacuum drying time is 24 h; the substrate is a Teflon substrate.
9. An all-solid-state battery, characterized in that, The composite solid electrolyte membrane as described in any one of claims 1 to 3 includes a positive electrode, a negative electrode, and a composite solid electrolyte membrane located between the positive electrode and the negative electrode, or a composite solid electrolyte membrane prepared by any one of claims 4 to 8.
10. The all-solid-state battery as described in claim 9, characterized in that, The cathode comprises a high-nickel ternary cathode material LiNi. 0.8 Co 0.1 Mn 0.1 O2 (NCM811); the negative electrode is a lithium indium alloy (Li-In); the all-solid-state battery is a mold battery with external stacking pressure applied, the stacking pressure range being 50~80 MPa.