An organic composite coating modified solid-state electrolyte and a preparation method thereof
Patent Information
- Application Number
- CN202610808140.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-06-05
- Publication Date
- 2026-08-28
AI Technical Summary
[0006]本发明提供一种有机复合包覆改性的固态电解质及其制备方法，旨在解决现有卤化物固态电解质空气稳定性差、界面阻抗高的技术问题
（1）采用烷基膦酸包覆在卤化物电解质表面，可在其表面形成一层致密且极薄的疏水层，该疏水层能有效隔绝空气中的水汽，抑制卤化物电解质的水解反应，从而显著提升卤化物电解质的稳定性；
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of solid electrolyte technology, specifically relating to an organic composite-coated modified solid electrolyte and its preparation method. Background Technology
[0002] All-solid-state lithium batteries are considered an ideal choice for next-generation electrochemical energy storage systems due to their combination of high safety and high energy density. Solid-state electrolytes, as the core material of all-solid-state batteries, directly determine the overall performance of the battery. In recent years, halide solid-state electrolytes (such as Li3YCl6 and Li3InCl6) have attracted widespread attention due to their high ionic conductivity, wide electrochemical window, good cold-pressing formability, and relatively superior humidity tolerance compared to sulfides, demonstrating their application potential in practical solid-state batteries.
[0003] However, halide solid-state electrolytes still face two major challenges in practical applications. First, most halides remain sensitive to moisture and are prone to hydrolysis when exposed to air for extended periods, leading to electrolyte structure degradation and a sharp decline in ionic conductivity. This imposes stringent environmental control requirements on material preparation, storage, transportation, and battery assembly processes. Second, the solid-solid interface between halide electrolytes and oxide cathodes (such as high-nickel ternary materials and lithium cobalt oxide) suffers from poor contact and space charge layer effects, resulting in a significant increase in interfacial impedance and limiting the rate performance and cycle stability of all-solid-state batteries.
[0004] To overcome these shortcomings, researchers have proposed surface coating modification strategies. Common methods include forming a protective layer on the surface of halide particles using inorganic oxides (such as Al₂O₃, LiNbO₃, and LiTaO₃) or polymers (such as PEO and PMMA). However, single inorganic coatings often fail to fully adapt to changes in particle morphology due to rigid contact, and may introduce additional interfacial resistance between the coating layer and the electrolyte. While simple polymer coatings can improve interfacial flexibility, they typically lack sufficient mechanical strength and have limited effectiveness in blocking moisture. More importantly, most existing coating methods are complex (such as atomic layer deposition and sol-gel methods), making it difficult to achieve uniform, controllable, and large-scale preparation.
[0005] Therefore, developing a modification method that combines good moisture barrier properties with interfacial compatibility, is simple to process, and has controllable costs is of great significance for promoting the practical application of halide solid electrolytes. Summary of the Invention
[0006] This invention provides an organic composite-coated modified solid electrolyte and its preparation method, aiming to solve the technical problems of poor air stability and high interfacial impedance of existing halide solid electrolytes.
[0007] To solve the above-mentioned technical problems, the present invention is implemented as follows: A method for preparing an organic composite-coated modified solid electrolyte includes the following steps: Step S1: Using a halide electrolyte as the matrix material, the following components are added in a mass percentage relative to the matrix material: 2-5% alkylphosphonic acid, 0.5-1.5% fluorinated ferroelectric copolymer, and 0.5-1.5% lithium salt; after mixing, solvent is added at a solid-liquid ratio of 1:2-1:4 g / mL to obtain a slurry; Step S2: The slurry is ball-milled to fully coat the halide electrolyte particles with alkylphosphonic acid, while dispersing the fluorinated ferroelectric copolymer and lithium salt. Step S3: After ball milling, the slurry is removed, vacuum dried, and then ground under an inert atmosphere. After grinding, it is passed through a 200-300 mesh sieve to obtain a uniform organic composite-coated modified solid electrolyte powder.
[0008] As a preferred improvement, the alkylphosphonic acid is selected from at least one of octadecylphosphonic acid, hexadecylphosphonic acid, and tetradecylphosphonic acid.
[0009] As a preferred improvement, the fluorinated ferroelectric copolymer is selected from at least one of vinylidene fluoride-trifluoroethylene-chlorotrifluoroethylene, poly(vinylidene fluoride-trifluoroethylene), and poly(vinylidene fluoride-tetrafluoroethylene).
[0010] As a preferred improvement, the lithium salt is selected from at least one of LiTFSI, LiFSI, and LiPF6.
[0011] As a preferred improvement, the solvent is selected from n-butanol, cyclohexane, and dimethyl carbonate.
[0012] As a preferred improvement, the ball milling process specifically includes the following steps: loading the slurry and zirconia balls into a ball milling jar, with a ball-to-material mass ratio of 5:1-20:1, and milling at a speed of 250-350 rpm for 6-10 hours.
[0013] As a preferred improvement, the vacuum drying temperature is 100-130℃ and the time is 10-20 hours.
[0014] As a preferred improvement, the halide electrolyte is selected from Li3InCl6, Li 1.75 ZrO 0.5 Cl 4.75 At least one of Li3YBr3Cl3.
[0015] An organic composite-coated modified solid electrolyte is prepared by the above-described preparation method. The organic composite-coated modified solid electrolyte has an ionic conductivity of not less than 1 mS / cm at 25°C.
[0016] Compared with the prior art, the present invention has the following beneficial effects: (1) By coating the surface of the halide electrolyte with alkylphosphonic acid, a dense and extremely thin hydrophobic layer can be formed on its surface. This hydrophobic layer can effectively isolate water vapor in the air and inhibit the hydrolysis reaction of the halide electrolyte, thereby significantly improving the stability of the halide electrolyte. (2) Fluorine-containing ferroelectric copolymers and lithium salts have a synergistic effect: Fluorine-containing ferroelectric copolymers have a high dielectric constant, which can effectively promote the dissociation of lithium salts and release more free lithium ions; while lithium ions in lithium salts can provide free lithium ions to improve ionic conductivity. At the same time, lithium ions interact with fluorine and chlorine atoms in the copolymer, which helps to uniformly disperse halide electrolyte particles and avoid agglomeration, thereby constructing a continuous and efficient lithium ion transport channel and improving the ionic conductivity of the coated halide electrolyte.
[0017] Ultimately, a stable organic composite halide solid electrolyte with excellent ionic conductivity was obtained. Detailed Implementation
[0018] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0019] This embodiment provides a method for preparing an organic composite-coated modified solid electrolyte, comprising the following steps: Step S1: Using a halide electrolyte as the matrix material, the following components are added in a mass percentage relative to the matrix material: 2-5% alkylphosphonic acid, 0.5-1.5% fluorinated ferroelectric copolymer, and 0.5-1.5% lithium salt; after mixing, solvent is added at a solid-liquid ratio of 1:2-1:4 g / mL to obtain a slurry; The halide electrolyte is selected from Li3InCl6, Li 1.75 ZrO 0.5 Cl 4.75 At least one of Li3YBr3Cl3.
[0020] The alkylphosphonic acid is selected from at least one of octadecylphosphonic acid, hexadecylphosphonic acid, and tetradecylphosphonic acid.
[0021] The fluorinated ferroelectric copolymer is selected from at least one of vinylidene fluoride-trifluoroethylene-chlorotrifluoroethylene (PVTC), poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)), and poly(vinylidene fluoride-tetrafluoroethylene) (P(VDF-TFE)).
[0022] The lithium salt is selected from at least one of LiTFSI, LiFSI, and LiPF6.
[0023] The solvent is selected from one of n-butanol, cyclohexane, and dimethyl carbonate (DMC).
[0024] Step S2 involves ball milling the slurry to fully coat the halide electrolyte particles with alkylphosphonic acid, while simultaneously dispersing the fluorinated ferroelectric copolymer and lithium salt.
[0025] The ball milling process specifically includes the following steps: the slurry and zirconia balls are loaded into the ball mill jar, with a ball-to-material mass ratio of 5:1-20:1, and the balls are milled at a speed of 250-350 rpm for 6-10 hours.
[0026] Step S3: After ball milling, the slurry is removed, vacuum dried, and then ground under an inert atmosphere. After grinding, it is passed through a 200-300 mesh sieve to obtain a uniform organic composite-coated modified solid electrolyte powder.
[0027] Vacuum drying is performed at a temperature of 100-130℃ for 10-20 hours to completely remove the solvent.
[0028] This embodiment also provides an organic composite-coated modified solid electrolyte, which is prepared by the above-described preparation method. The organic composite-coated modified solid electrolyte has an ionic conductivity of not less than 1 mS / cm at 25°C.
[0029] Example 1 This embodiment provides a method for preparing an organic composite-coated modified solid electrolyte, comprising the following steps: Weigh 5g Li3InCl6, 0.15g octadecylphosphonic acid, 0.05g PVTC and 0.05g LiTFSI and place them in a ball mill jar. Measure 16mL of n-butanol and mix it with the above solids.
[0030] The mixture was loaded into a ball mill jar with 80g of zirconia balls and milled at 300rpm for 8 hours.
[0031] Remove the slurry and place it in a vacuum drying oven to dry at 130°C for 15 hours.
[0032] The blocky product was ground and dried in an inert atmosphere and passed through a 200-mesh sieve to obtain an organically composite-coated modified Li3InCl6 solid electrolyte material.
[0033] Example 2 Weigh 5g Li3InCl6, 0.15g hexadecylphosphonic acid, 0.05g P(VDF-TrFE) and 0.05g LiFSI and place them in a ball mill jar. Measure 16mL of n-butanol and mix it with the above solids.
[0034] The mixture was loaded into a ball mill jar with 80g of zirconia balls and milled at 300rpm for 8 hours.
[0035] Remove the slurry and place it in a vacuum drying oven to dry at 130°C for 15 hours.
[0036] The blocky product was ground and dried in an inert atmosphere and passed through a 200-mesh sieve to obtain an organically composite-coated modified Li3InCl6 solid electrolyte material.
[0037] Example 3 Weigh 5g Li3InCl6, 0.15g tetradecylphosphonic acid, 0.05g P(VDF-TFE) and 0.05g LiPF6 and place them in a ball mill jar. Measure 16mL of cyclohexane and mix it with the above solids.
[0038] The mixture was loaded into a ball mill jar with 80g of zirconia balls and milled at 300rpm for 8 hours.
[0039] Remove the slurry and place it in a vacuum drying oven to dry at 100°C for 15 hours.
[0040] The blocky product was ground and dried in an inert atmosphere and passed through a 200-mesh sieve to obtain an organically composite-coated modified Li3InCl6 solid electrolyte material.
[0041] Example 4 This embodiment provides a method for preparing an organic composite-coated modified solid electrolyte, comprising the following steps: Weigh 5g Li 1.75 ZrO 0.5 Cl 4.75 0.15 g tetradecylphosphonic acid, 0.05 g PVTC and 0.05 g LiTFSI were placed in a ball mill jar, and 16 mL of n-butanol was measured and mixed with the above solids.
[0042] The mixture was loaded into a ball mill jar with 80g of zirconia balls and milled at 300rpm for 8 hours.
[0043] Remove the slurry and place it in a vacuum drying oven to dry at 130°C for 15 hours.
[0044] The dried block product was ground in an inert atmosphere and passed through a 200-mesh sieve to obtain organically composite-coated modified Li. 1.75 ZrO0.5 Cl 4.75 Solid electrolyte materials.
[0045] Example 5 This embodiment provides a method for preparing an organic composite-coated modified solid electrolyte, comprising the following steps: Weigh 5g Li 1.75 ZrO 0.5 Cl 4.75 0.15 g of hexadecylphosphonic acid, 0.05 g of P (VDF-TrFE) and 0.05 g of LiPF6 were placed in a ball mill jar, and 16 mL of cyclohexane was measured and mixed with the above solids.
[0046] The mixture was loaded into a ball mill jar with 80g of zirconia balls and milled at 300rpm for 8 hours.
[0047] Remove the slurry and place it in a vacuum drying oven to dry at 100°C for 15 hours.
[0048] The dried block product was ground in an inert atmosphere and passed through a 200-mesh sieve to obtain organically composite-coated modified Li. 1.75 ZrO 0.5 Cl 4.75 Solid electrolyte materials.
[0049] Example 6 This embodiment provides a method for preparing an organic composite-coated modified solid electrolyte, comprising the following steps: Weigh 5g Li 1.75 ZrO 0.5 Cl 4.75 0.15 g tetradecylphosphonic acid, 0.05 g P (VDF-TFE) and 0.05 g LiFSI were placed in a ball mill jar, and 16 mL of dimethyl carbonate (DMC) was measured and mixed with the above solids.
[0050] The mixture was loaded into a ball mill jar with 80g of zirconia balls and milled at 300rpm for 8 hours.
[0051] Remove the slurry and place it in a vacuum drying oven to dry at 110°C for 15 hours.
[0052] The dried block product was ground in an inert atmosphere and passed through a 200-mesh sieve to obtain organically composite-coated modified Li. 1.75 ZrO 0.5 Cl 4.75 Solid electrolyte materials.
[0053] Example 7 This embodiment provides a method for preparing an organic composite-coated modified solid electrolyte, comprising the following steps: Weigh 5g Li3YBr3Cl3, 0.15g hexadecylphosphonic acid, 0.05g PVTC and 0.05g LiFSI and place them in a ball mill jar. Measure 16mL of dimethyl carbonate (DMC) and mix it with the above solids.
[0054] The mixture was loaded into a ball mill jar with 80g of zirconia balls and milled at 300rpm for 8 hours.
[0055] Remove the slurry and place it in a vacuum drying oven to dry at 110°C for 16 hours.
[0056] The blocky product, after being ground and dried in an inert atmosphere, was passed through a 200-mesh sieve to obtain an organically composite-coated modified Li3YBr3Cl3 solid electrolyte material.
[0057] Example 8 This embodiment provides a method for preparing an organic composite-coated modified solid electrolyte, comprising the following steps: Weigh 5g Li3YBr3Cl3, 0.15g octadecylphosphonic acid, 0.05g P(VDF-TFE) and 0.05g LiTFSI and place them in a ball mill jar. Measure 16mL of n-butanol and mix it with the above solids.
[0058] The mixture was loaded into a ball mill jar with 80g of zirconia balls and milled at 300rpm for 8 hours.
[0059] Remove the slurry and place it in a vacuum drying oven to dry at 130°C for 15 hours.
[0060] The blocky product, after being ground and dried in an inert atmosphere, was passed through a 200-mesh sieve to obtain an organically composite-coated modified Li3YBr3Cl3 solid electrolyte material.
[0061] Example 9 Weigh 5g Li3YBr3Cl3, 0.15g octadecylphosphonic acid, 0.05g PVTC and 0.05g LiPF6 and place them in a ball mill jar. Measure 16mL of cyclohexane and mix it with the above solids. The mixture was loaded into a ball mill jar with 80g of zirconia balls and milled at 300rpm for 8 hours.
[0062] Remove the slurry and place it in a vacuum drying oven to dry at 100°C for 15 hours.
[0063] The blocky product, after being ground and dried in an inert atmosphere, was passed through a 200-mesh sieve to obtain an organically composite-coated modified Li3YBr3Cl3 solid electrolyte material.
[0064] Comparative Example 1 Unmodified halide electrolyte Li3InCl6.
[0065] Comparative Example 2: Unmodified halide electrolyte Li 1.75 ZrO 0.5 Cl 4.75 .
[0066] Comparative Example 3 Unmodified halide electrolyte Li3YBr3Cl3.
[0067] Solid electrolyte samples from Examples 1-9 and Comparative Examples 1-3 were subjected to room temperature ionic conductivity tests at 25°C. The specific testing procedure was as follows: 100 mg of electrolyte powder was weighed and placed in an insulating sleeve with an inner diameter of 10 mm. The sample was then pressurized at 350 MPa and subjected to AC impedance spectroscopy to measure the impedance value of the electrolyte material. The thickness of the pressurized sheet electrolyte was then measured. Based on the sheet impedance value, thickness value, and area, the ionic conductivity of the electrolyte material was calculated using the formula σ = d / (R × S), where σ is the ionic conductivity in mS / cm; d is the sheet thickness in cm; R is the impedance value in Ω; and S is the sheet area in cm². 2 The test results are shown in Table 1.
[0068] Table 1. Results of Ion Conductivity Test (Test temperature: 25℃) As shown in Table 1, the organic composite coating modification strategy exhibits good process tunability in maintaining the ionic conductivity of halide solid electrolytes. For the Li3InCl6 system, the conductivity after coating modification (1.15-1.28 mS / cm) is slightly lower than that of the unmodified sample (1.35 mS / cm), but still remains above 1.1 mS / cm overall. For Li 1.75 ZrO 0.5 Cl 4.75 For the modified system, the conductivity (1.34-1.40 mS / cm) decreased by 8%-12% compared to the unmodified sample (1.52 mS / cm). For the Li3YBr3Cl3 system, the conductivity (4.35-4.88 mS / cm) decreased by only 4%-14% compared to the unmodified sample (5.08 mS / cm). Among them, Example 9 (4.88 mS / cm) was almost the same as the unmodified sample, showing extremely low ion conduction loss.
[0069] In summary, the organic composite coating composed of alkylphosphonic acid, fluorinated ferroelectric copolymer, and lithium salt is an efficient and universal surface modification strategy that causes minimal damage to the intrinsic ionic conductivity of halide electrolytes, providing a practical approach to improve their air stability. By rationally controlling the alkyl chain length, copolymer type, lithium salt type, and process solvent, a synergistic balance between high ionic conductivity and excellent environmental tolerance can be achieved in different halide systems.
[0070] The embodiments of the present invention have been described above. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of the present invention.
Claims
1. A method for preparing an organically composite-coated modified solid electrolyte, characterized in that, Includes the following steps: Step S1: Using a halide electrolyte as the matrix material, the following components are added in a mass percentage relative to the matrix material: 2-5% alkylphosphonic acid, 0.5-1.5% fluorinated ferroelectric copolymer, and 0.5-1.5% lithium salt; after mixing, solvent is added at a solid-liquid ratio of 1:2-1:4 g / mL to obtain a slurry; Step S2: The slurry is ball-milled to fully coat the halide electrolyte particles with alkylphosphonic acid, while dispersing the fluorinated ferroelectric copolymer and lithium salt. Step S3: After ball milling, the slurry is removed, vacuum dried, and then ground under an inert atmosphere. After grinding, it is passed through a 200-300 mesh sieve to obtain a uniform organic composite-coated modified solid electrolyte powder.
2. The preparation method according to claim 1, characterized in that, The alkylphosphonic acid is selected from at least one of octadecylphosphonic acid, hexadecylphosphonic acid, and tetradecylphosphonic acid.
3. The preparation method according to claim 1, characterized in that, The fluorinated ferroelectric copolymer is selected from at least one of vinylidene fluoride-trifluoroethylene-chlorotrifluoroethylene, poly(vinylidene fluoride-trifluoroethylene), and poly(vinylidene fluoride-tetrafluoroethylene).
4. The preparation method according to claim 1, characterized in that, The lithium salt is selected from at least one of LiTFSI, LiFSI, and LiPF6.
5. The preparation method according to claim 1, characterized in that, The solvent is selected from one of n-butanol, cyclohexane, and dimethyl carbonate.
6. The preparation method according to claim 1, characterized in that, The ball milling process specifically includes the following steps: the slurry and zirconia balls are loaded into the ball mill jar, with a ball-to-material mass ratio of 5:1-20:1, and the balls are milled at a speed of 250-350 rpm for 6-10 hours.
7. The preparation method according to claim 1, characterized in that, The vacuum drying temperature is 100-130℃, and the time is 10-20 hours.
8. The preparation method according to claim 1, characterized in that, The halide electrolyte is selected from Li3InCl6, Li 1.75 ZrO 0.5 Cl 4.75 At least one of Li3YBr3Cl3.
9. An organic composite-coated modified solid electrolyte, characterized in that, The solid electrolyte, prepared by any one of claims 1-8, has an ionic conductivity of not less than 1 mS / cm at 25°C.