A Sulfide-Polymer Composite Solid-State Electrolyte and Its Preparation Method

Abstract

The present invention provides a sulfide-polymer composite solid electrolyte and a preparation method thereof, belonging to the field of batteries. In the present invention, lithium sulfide reacts with phosphorus pentasulfide to generate a partially crystallized sulfide network, and high-valent metal ions are doped to optimize the lattice structure, enhancing conductivity and chemical stability; the crystalline phase provides an efficient ion migration channel, and the amorphous region reduces the grain boundary effect and improves the conduction uniformity; a metal chloride and lithium fluoride coating layer is used to isolate moisture and oxygen, and polyaniline coating reduces the interfacial impedance and enhances the cycle stability. The crystallinity is reduced and the amorphous region is increased by sulfonated polyether ether ketone, providing a low-impedance path for lithium ions; the polyethylene glycol chain segment improves the flexibility and ion migration ability, and the three-dimensional network structure is formed by crosslinking to enhance the mechanical strength and interfacial stability. The inorganic phase and the polymer act synergistically to construct a bicontinuous ion conductive network to improve the comprehensive performance.

Description

Technical Field

[0001] The present invention belongs to the technical field of batteries and relates to a sulfide-polymer composite solid electrolyte and a preparation method thereof. Background Art

[0002] In recent years' research on solid-state batteries, solid electrolytes have gradually become a research hotspot due to their superior safety and high energy density. Compared with traditional liquid batteries, solid-state batteries have higher safety, which can effectively reduce the risks of leakage, combustion, and explosion. At the same time, the high energy density of solid electrolytes makes the batteries more advantageous in terms of volume and weight, and is suitable for high-energy-demand application scenarios such as electric vehicles and energy storage systems.

[0003] Among various types of solid electrolytes, sulfide-polymer composite solid electrolytes have attracted much attention due to their unique material properties. This type of composite material combines the advantages of sulfide electrolytes and polymer electrolytes, making it excellent in terms of ionic conductivity and mechanical strength. Sulfide electrolytes, such as lithium sulfide and phosphorus pentasulfide, exhibit extremely high ionic conductivity, usually reaching the level of liquid electrolytes. However, these sulfide materials generally have the problems of high brittleness and easy deliquescence, which limit their wide application and durability in practical applications. On the other hand, polymer electrolytes are known for their good flexibility and processability, and can achieve good adaptation in batteries of different shapes and sizes, but their ionic conductivity is relatively low and usually cannot meet the requirements of high-power applications. By combining these two materials to form a sulfide-polymer composite solid electrolyte, the respective deficiencies can be effectively overcome and the overall performance can be improved. This composite material can not only improve ionic conductivity but also enhance mechanical strength, thereby improving the stability and service life of the electrolyte.

[0004] Nevertheless, the existing sulfide-polymer composite solid electrolytes still have some deficiencies. First, traditional composite methods often lead to phase separation, which affects the overall ionic conductivity and mechanical properties of the electrolyte and results in a decrease in battery efficiency. Second, the interfacial compatibility between sulfide and polymer is poor, which may cause an increase in interfacial impedance. This impedance will limit the transport of ions in the electrolyte and further reduce the overall performance of the battery. Therefore, research and improvement aiming at these deficiencies are an important topic in the current field of solid-state batteries and the key to promoting the commercialization of this technology. Summary of the Invention

[0005] To address the above problems, the object of the present invention is to provide a sulfide-polymer composite solid electrolyte and a preparation method thereof. In the present invention, a partially crystallized sulfide network is generated through the mechanochemical reaction of lithium sulfide and phosphorus pentasulfide, and the lattice structure is optimized by doping with high-valent metal ions to reduce the lithium ion migration energy barrier, enhance conductivity and chemical stability. The crystalline phase structure provides an efficient lithium ion migration channel, while the amorphous region reduces the grain boundary effect and improves the ionic conductivity uniformity; at the same time, a coating layer of metal chloride and lithium fluoride isolates moisture and oxygen in the environment, significantly enhancing the environmental stability and durability of the inorganic phase, and the coating of polyaniline further improves the structural stability of the material during cycling by reducing the interfacial impedance and enhancing flexibility. Sulfonated polyether ether ketone improves the lithium affinity by introducing sulfonic acid groups, reduces the crystallinity and increases the amorphous region, providing a low-impedance path for lithium ion transport; the polyethylene glycol segment enhances the flexibility and ion migration ability, and forms a three-dimensional network structure through crosslinking, further improving the mechanical strength and interfacial stability. Finally, the inorganic phase forms a bicontinuous ion conductive network through the high-conductivity main channel and the flexible filling effect of the polymer. Combining the interface optimization of the coating layer and the conductive polymer effectively reduces the interfacial impedance and enhances the ion transport performance. The synergistic effect of the inorganic phase and the polymer significantly improves the conductivity, mechanical properties and cycling stability of the material.

[0006] To achieve this purpose, the present invention adopts the following technical solutions:

[0007] In the first aspect, the present invention provides a preparation method of a sulfide-polymer composite solid electrolyte, and the preparation method of the sulfide-polymer composite solid electrolyte includes:

[0008] S1: Heat-treat the mixed powder obtained by mixing and ball-milling sulfide and inorganic salt in an argon atmosphere to obtain an inorganic core body;

[0009] S2: Melt and cool lithium sulfide and phosphorus pentasulfide and then heat-treat to obtain an inorganic phase precursor; mix the inorganic phase precursor with the inorganic core body and heat-treat to obtain a composite inorganic phase;

[0010] S3: Dissolve indium trichloride and lithium chloride in absolute ethanol, add acetic acid and reflux to react to obtain a precursor solution, react the composite inorganic phase with the precursor solution, and heat-treat to obtain a first-coated inorganic phase;

[0011] S4: Disperse ammonium fluoride and lithium acetate in absolute ethanol to obtain a second precursor solution, react the first-coated inorganic phase with the second precursor solution, heat-treat to obtain a double-coated product; compound polyaniline with the double-coated product to obtain a conductive layer-coated inorganic phase;

[0012] S5: Disperse polyetheretherketone in concentrated sulfuric acid to react to obtain sulfonated polyetheretherketone, and react it with methoxypolyethylene glycol to obtain a modified polymer;

[0013] S6: Disperse the modified polymer in N,N-dimethylformamide, add a conductive layer-coated inorganic phase, a crosslinking agent, an initiator, and a lithium salt, and then mix to obtain a homogeneous mixture, and cast and crosslink it into a composite solid electrolyte.

[0014] Specifically,

[0015] S1: Mix a sulfide and an inorganic salt and ball-mill to obtain a mixed powder; perform heat treatment on the mixed powder in an argon atmosphere to obtain an inorganic core;

[0016] S2: Melt lithium sulfide and phosphorus pentasulfide in an argon atmosphere and then cool to obtain a vitreous precursor, and perform heat treatment on it to obtain an inorganic phase precursor; mix the inorganic phase precursor and the inorganic core and ball-mill them, and then perform heat treatment to obtain a composite inorganic phase;

[0017] S3: Dissolve indium trichloride and lithium chloride in absolute ethanol, add acetic acid to adjust the pH, and reflux to obtain a precursor solution; disperse the composite inorganic phase in absolute ethanol to obtain a composite inorganic phase dispersion, dropwise add the precursor solution at a constant temperature and stir, centrifuge, wash, and perform heat treatment in an argon atmosphere to obtain a first-coated inorganic phase;

[0018] S4: Disperse ammonium fluoride and lithium acetate in absolute ethanol to obtain a second precursor solution; disperse the first-coated inorganic phase in absolute ethanol to obtain dispersion A, dropwise add the second precursor solution and stir, centrifuge, wash, and perform heat treatment in an argon atmosphere to obtain a double-layer-coated inorganic phase; disperse polyaniline in N-methylpyrrolidone to obtain dispersion B, add the double-layer-coated inorganic phase to dispersion B and stir at room temperature, centrifuge, wash, and dry to obtain a conductive layer-coated inorganic phase.

[0019] S5: Disperse polyetheretherketone in concentrated sulfuric acid, stir, slowly pour the reaction solution into ice water, filter, wash, and vacuum dry to obtain sulfonated polyetheretherketone; disperse it in N,N-dimethylformamide, add a sodium hydroxide solution to adjust the pH, dropwise add a N,N-dimethylformamide solution of methoxypolyethylene glycol, react to obtain a reaction solution, pour the reaction solution into deionized water, filter, wash, and dry to obtain a modified polymer;

[0020] S6: Disperse the modified polymer in N,N-dimethylformamide, add polyethylene glycol dimethacrylate and azobisisobutyronitrile, and obtain a polymer solution by ultrasonic dispersion; disperse the conductive layer-coated inorganic phase in N,N-dimethylformamide, the mass ratio of the modified polymer to the conductive layer-coated inorganic phase is (20 - 40):(60 - 80), add the polymer solution, then add a lithium salt and disperse evenly to obtain a homogeneous mixture, and form a film by casting, followed by pre-drying, thermal-initiated crosslinking, and vacuum drying to obtain a sulfide-polymer composite solid electrolyte.

[0021] As a preferred technical solution of the present invention, in step S1, the molar ratio of lithium sulfide to phosphorus pentasulfide is 7 - 8:3, for example, it can be 7.0:3, 7.1:3, 7.2:3, 7.3:3, 7.4:3, 7.5:3, 7.6:3, 7.7:3, 7.8:3, 7.9:3 or 8.0:3, but is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0022] In some alternative embodiments, the molar ratio of the sulfide to the inorganic salt is 1:0.05 - 0.15, for example, it can be 1:0.05, 1:0.06, 1:0.07, 1:0.08, 1:0.09, 1:0.10, 1:0.11, 1:0.12, 1:0.13, 1:0.14 or 1:0.15, but is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0023] In some alternative embodiments, the heating rate of the heat treatment of the mixed powder is 5 - 10 °C / min, for example, it can be 5.0 °C / min, 5.5 °C / min, 6.0 °C / min, 6.5 °C / min, 7.0 °C / min, 7.5 °C / min, 8.0 °C / min, 8.5 °C / min, 9.0 °C / min, 9.5 °C / min or 10.0 °C / min, but is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0024] In some alternative embodiments, the temperature of the heat treatment of the mixed powder is 300 - 400 °C, for example, it can be 300 °C, 310 °C, 320 °C, 330 °C, 340 °C, 350 °C, 360 °C, 370 °C, 380 °C, 390 °C or 400 °C, but is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0025] In some alternative embodiments, the heat treatment time of the mixed powder is 2 - 3 h, for example, it can be 2.0 h, 2.1 h, 2.2 h, 2.3 h, 2.4 h, 2.5 h, 2.6 h, 2.7 h, 2.8 h, 2.9 h or 3.0 h, but is not limited to the listed values, and other unlisted values within this value range are equally applicable.

[0026] As a preferred technical solution of the present invention, in step S2, the molar ratio of lithium sulfide to phosphorus pentasulfide is 2 - 2.5:1, for example, it can be 2.00:1, 2.05:1, 2.10:1, 2.15:1, 2.20:1, 2.25:1, 2.30:1, 2.35:1, 2.40:1, 2.45:1 or 2.50:1, but is not limited to the listed values, and other unlisted values within this value range are equally applicable.

[0027] In some alternative embodiments, the melting temperature is 550 - 600 °C, for example, it can be 550 °C, 555 °C, 560 °C, 565 °C, 570 °C, 575 °C, 580 °C, 585 °C, 590 °C, 595 °C or 600 °C, but is not limited to the listed values, and other unlisted values within this value range are equally applicable.

[0028] In some alternative embodiments, the melting time is 10 - 20 min, for example, it can be 10 min, 11 min, 12 min, 13 min, 14 min, 15 min, 16 min, 17 min, 18 min, 19 min or 20 min, but is not limited to the listed values, and other unlisted values within this value range are equally applicable.

[0029] In some alternative embodiments, the heat treatment temperature of the glassy precursor is 250 - 300 °C, for example, it can be 250 °C, 255 °C, 260 °C, 265 °C, 270 °C, 275 °C, 280 °C, 285 °C, 290 °C, 295 °C or 300 °C, but is not limited to the listed values, and other unlisted values within this value range are equally applicable.

[0030] In some alternative embodiments, the heat treatment time of the glassy precursor is 2 - 3 h, for example, it can be 2.0 h, 2.1 h, 2.2 h, 2.3 h, 2.4 h, 2.5 h, 2.6 h, 2.7 h, 2.8 h, 2.9 h or 3.0 h, but is not limited to the listed values, and other unlisted values within this value range are equally applicable.

[0031] In some alternative embodiments, the mass ratio of the inorganic phase precursor to the inorganic core is 8-9:1. For example, it can be 8.0:1, 8.1:1, 8.2:1, 8.3:1, 8.4:1, 8.5:1, 8.6:1, 8.7:1, 8.8:1, 8.9:1 or 9.0:1. However, it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0032] In some alternative embodiments, the heat treatment temperature after the inorganic phase precursor and the inorganic core are mixed and ball-milled is 300-400°C. For example, it can be 300°C, 310°C, 320°C, 330°C, 340°C, 350°C, 360°C, 370°C, 380°C, 390°C or 400°C. However, it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0033] In some alternative embodiments, the heat treatment time after the inorganic phase precursor and the inorganic core are mixed and ball-milled is 1-2 h. For example, it can be 1.0 h, 1.1 h, 1.2 h, 1.3 h, 1.4 h, 1.5 h, 1.6 h, 1.7 h, 1.8 h, 1.9 h or 2.0 h. However, it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0034] As a preferred technical solution of the present invention, in step S3, the molar ratio of indium trichloride to lithium chloride is 1:2-3. For example, it can be 1:2.0, 1:2.1, 1:2.2, 1:2.3, 1:2.4, 1:2.5, 1:2.6, 1:2.7, 1:2.8, 1:2.9 or 1:3.0. However, it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0035] In some alternative embodiments, the concentration of indium trichloride in absolute ethanol is 0.1-0.3 M. For example, it can be 0.10 M, 0.11 M, 0.12 M, 0.13 M, 0.14 M, 0.15 M, 0.16 M, 0.17 M, 0.18 M, 0.19 M or 0.20 M. However, it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0036] In some alternative embodiments, acetic acid is added to adjust the pH to 4-5. For example, it can be 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9 or 5.0. However, it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0037] In some alternative embodiments, the temperature of the reflux is 50 - 60 °C. For example, it can be 50 °C, 51 °C, 52 °C, 53 °C, 54 °C, 55 °C, 56 °C, 57 °C, 58 °C, 59 °C, or 60 °C. However, it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0038] In some alternative embodiments, the time of the reflux is 2 - 3 h. For example, it can be 2.0 h, 2.1 h, 2.2 h, 2.3 h, 2.4 h, 2.5 h, 2.6 h, 2.7 h, 2.8 h, 2.9 h, or 3.0 h. However, it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0039] In some alternative embodiments, the mass fraction of the composite inorganic phase in absolute ethanol is 5 - 6 wt.%. For example, it can be 5.0 wt.%, 5.1 wt.%, 5.2 wt.%, 5.3 wt.%, 5.4 wt.%, 5.5 wt.%, 5.6 wt.%, 5.7 wt.%, 5.8 wt.%, 5.9 wt.%, or 6.0 wt.%. However, it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0040] In some alternative embodiments, the mass ratio of the composite inorganic phase to the precursor solution is 1:8 - 12. For example, it can be 1:8.0, 1:8.4, 1:8.8, 1:9.2, 1:9.6, 1:10.0, 1:10.4, 1:10.8, 1:11.2, 1:11.6, or 1:12.0. However, it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0041] In some alternative embodiments, the composite inorganic phase dispersion is dropped into the precursor solution at a constant temperature of 60 - 70 °C. For example, it can be 60 °C, 61 °C, 62 °C, 63 °C, 64 °C, 65 °C, 66 °C, 67 °C, 68 °C, 69 °C, or 70 °C. However, it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0042] In some alternative embodiments, the composite inorganic phase dispersion is dropped into the precursor solution at a constant temperature and stirred for 4 - 5 h. For example, it can be 4.0 h, 4.1 h, 4.2 h, 4.3 h, 4.4 h, 4.5 h, 4.6 h, 4.7 h, 4.8 h, 4.9 h, or 5.0 h. However, it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0043] In some alternative embodiments, the temperature of the heat treatment is 250 - 300 °C. For example, it can be 250 °C, 255 °C, 260 °C, 265 °C, 270 °C, 275 °C, 280 °C, 285 °C, 290 °C, 295 °C or 300 °C. However, it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0044] In some alternative embodiments, the time of the heat treatment is 1 - 2 h. For example, it can be 1.0 h, 1.1 h, 1.2 h, 1.3 h, 1.4 h, 1.5 h, 1.6 h, 1.7 h, 1.8 h, 1.9 h or 2.0 h. However, it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0045] As a preferred technical solution of the present invention, in step S4, the concentration of ammonium fluoride dispersed in absolute ethanol is 0.2 - 0.3 mol / L. For example, it can be 0.20 mol / L, 0.21 mol / L, 0.22 mol / L, 0.23 mol / L, 0.24 mol / L, 0.25 mol / L, 0.26 mol / L, 0.27 mol / L, 0.28 mol / L, 0.29 mol / L or 0.30 mol / L. However, it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0046] In some alternative embodiments, the concentration of lithium acetate dispersed in absolute ethanol is 0.2 - 0.3 mol / L. For example, it can be 0.20 mol / L, 0.21 mol / L, 0.22 mol / L, 0.23 mol / L, 0.24 mol / L, 0.25 mol / L, 0.26 mol / L, 0.27 mol / L, 0.28 mol / L, 0.29 mol / L or 0.30 mol / L. However, it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0047] In some alternative embodiments, the mass fraction of the first coated inorganic phase in absolute ethanol is 3 - 4 wt.%. For example, it can be 3.0 wt.%, 3.1 wt.%, 3.2 wt.%, 3.3 wt.%, 3.4 wt.%, 3.5 wt.%, 3.6 wt.%, 3.7 wt.%, 3.8 wt.%, 3.9 wt.% or 4.0 wt.%. However, it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0048] In some alternative embodiments, the mass ratio of the first coating inorganic phase to the second precursor solution is 1:6 - 10. For example, it can be 1:6.0, 1:6.4, 1:6.8, 1:7.2, 1:7.6, 1:8.0, 1:8.4, 1:8.8, 1:9.2, 1:9.6 or 1:10.0. However, it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0049] In some alternative embodiments, the temperature for stirring after dropping the second precursor solution into the dispersion A is 50 - 60 °C. For example, it can be 50 °C, 51 °C, 52 °C, 53 °C, 54 °C, 55 °C, 56 °C, 57 °C, 58 °C, 59 °C or 60 °C. However, it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0050] In some alternative embodiments, the stirring time after dropping the second precursor solution into the dispersion A is 2 - 3 h. For example, it can be 2.0 h, 2.1 h, 2.2 h, 2.3 h, 2.4 h, 2.5 h, 2.6 h, 2.7 h, 2.8 h, 2.9 h or 3.0 h. However, it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0051] In some alternative embodiments, the temperature of the heat treatment is 150 - 160 °C. For example, it can be 150 °C, 151 °C, 152 °C, 153 °C, 154 °C, 155 °C, 156 °C, 157 °C, 158 °C, 159 °C or 160 °C. However, it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0052] In some alternative embodiments, the time of the heat treatment is 1 - 2 h. For example, it can be 1.0 h, 1.1 h, 1.2 h, 1.3 h, 1.4 h, 1.5 h, 1.6 h, 1.7 h, 1.8 h, 1.9 h or 2.0 h. However, it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0053] In some alternative embodiments, the mass fraction of polyaniline dispersed in N - methylpyrrolidone is 2 - 3 wt.%. For example, it can be 2.0 wt.%, 2.1 wt.%, 2.2 wt.%, 2.3 wt.%, 2.4 wt.%, 2.5 wt.%, 2.6 wt.%, 2.7 wt.%, 2.8 wt.%, 2.9 wt.% or 3.0 wt.%. However, it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0054] In some alternative embodiments, the mass ratio of the double-layer coated inorganic phase to polyaniline is 95:5 - 98:2. For example, it can be 95:5, 95.5:4.5, 96:4, 96.5:3.5, 97:3, 97.5:2.5, or 98:2. However, it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0055] In some alternative embodiments, the double-layer coated inorganic phase is added to dispersion liquid B and stirred at room temperature for 4 - 5 h. For example, it can be 4.0 h, 4.1 h, 4.2 h, 4.3 h, 4.4 h, 4.5 h, 4.6 h, 4.7 h, 4.8 h, 4.9 h, or 5.0 h. However, it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0056] As a preferred technical solution of the present invention, in step S5, the mass fraction of the polyether ether ketone in concentrated sulfuric acid is 4 - 5 wt.%. For example, it can be 4.0 wt.%, 4.1 wt.%, 4.2 wt.%, 4.3 wt.%, 4.4 wt.%, 4.5 wt.%, 4.6 wt.%, 4.7 wt.%, 4.8 wt.%, 4.9 wt.%, or 5.0 wt.%. However, it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0057] In some alternative embodiments, the temperature of the stirring is 40 - 50 °C. For example, it can be 40 °C, 41 °C, 42 °C, 43 °C, 44 °C, 45 °C, 46 °C, 47 °C, 48 °C, 49 °C, or 50 °C. However, it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0058] In some alternative embodiments, the time of the stirring is 10 - 12 h. For example, it can be 10.0 h, 10.2 h, 10.4 h, 10.6 h, 10.8 h, 11.0 h, 11.2 h, 11.4 h, 11.6 h, 11.8 h, or 12.0 h. However, it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0059] In some alternative embodiments, the mass fraction of the sulfonated polyether ether ketone in N,N-dimethylformamide is 10 - 15 wt.%. For example, it can be 10.0 wt.%, 10.5 wt.%, 11.0 wt.%, 11.5 wt.%, 12.0 wt.%, 12.5 wt.%, 13.0 wt.%, 13.5 wt.%, 14.0 wt.%, 14.5 wt.%, or 15.0 wt.%. However, it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0060] In some alternative embodiments, the concentration of the sodium hydroxide solution is 1-2 M. For example, it can be 1.0 M, 1.1 M, 1.2 M, 1.3 M, 1.4 M, 1.5 M, 1.6 M, 1.7 M, 1.8 M, 1.9 M or 2.0 M. However, it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0061] In some alternative embodiments, the pH is adjusted to 8-9 using the sodium hydroxide solution. For example, it can be 8.0, 8.1, 8.2, 8.3, 8.4, 8.5, 8.6, 8.7, 8.8, 8.9 or 9.0. However, it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0062] In some alternative embodiments, the mass fraction of the methoxypolyethylene glycol N,N-dimethylformamide solution is 15-20 wt.%. For example, it can be 15.0 wt.%, 15.5 wt.%, 16.0 wt.%, 16.5 wt.%, 17.0 wt.%, 17.5 wt.%, 18.0 wt.%, 18.5 wt.%, 19.0 wt.%, 19.5 wt.% or 20.0 wt.%. However, it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0063] In some alternative embodiments, the mass ratio of the methoxypolyethylene glycol to the sulfonated poly(ether ether ketone) is 1-2:1. For example, it can be 1.0:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1 or 2.0:1. However, it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0064] In some alternative embodiments, the temperature of the reaction is 70-80 °C. For example, it can be 70 °C, 71 °C, 72 °C, 73 °C, 74 °C, 75 °C, 76 °C, 77 °C, 78 °C, 79 °C or 80 °C. However, it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0065] In some alternative embodiments, the reaction time is 20-24 h. For example, it can be 20.0 h, 20.5 h, 21.0 h, 21.5 h, 22.0 h, 22.5 h, 23.0 h, 23.5 h or 24.0 h. However, it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0066] As a preferred technical solution of the present invention, in step S6, the mass fraction of the modified polymer in N,N-dimethylformamide is 10-15 wt.%, for example, it can be 10.0 wt.%, 10.5 wt.%, 11.0 wt.%, 11.5 wt.%, 12.0 wt.%, 12.5 wt.%, 13.0 wt.%, 13.5 wt.%, 14.0 wt.%, 14.5 wt.% or 15.0 wt.%, but is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0067] In some alternative embodiments, the mass ratio of the crosslinking agent to the modified polymer is 0.2-0.3:1, for example, it can be 0.20:1, 0.21:1, 0.22:1, 0.23:1, 0.24:1, 0.25:1, 0.26:1, 0.27:1, 0.28:1, 0.29:1 or 0.30:1, but is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0068] In some alternative embodiments, the feeding amount of the initiator is 0.05-0.15% of the mass of the crosslinking agent, for example, it can be 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.10%, 0.11%, 0.12%, 0.13%, 0.14% or 0.15%, but is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0069] In some alternative embodiments, the mass fraction of the conductive layer-coated inorganic phase in N,N-dimethylformamide is 15-20 wt.%, for example, it can be 15.0 wt.%, 15.5 wt.%, 16.0 wt.%, 16.5 wt.%, 17.0 wt.%, 17.5 wt.%, 18.0 wt.%, 18.5 wt.%, 19.0 wt.%, 19.5 wt.% or 20.0 wt.%, but is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0070] In some alternative embodiments, the concentration of the lithium salt in the homogeneous mixture is 0.1-0.3 M, for example, it can be 0.10 M, 0.12 M, 0.14 M, 0.16 M, 0.18 M, 0.20 M, 0.22 M, 0.24 M, 0.26 M, 0.28 M or 0.30 M, but is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0071] In some alternative embodiments, the temperature for pre-drying after casting into a film is 80 - 90 °C. For example, it can be 80 °C, 81 °C, 82 °C, 83 °C, 84 °C, 85 °C, 86 °C, 87 °C, 88 °C, 89 °C or 90 °C. However, it is not limited to the listed values, and other unlisted values within this range are equally applicable.

[0072] In some alternative embodiments, the time for pre-drying after casting into a film is 2 - 3 h. For example, it can be 2.0 h, 2.1 h, 2.2 h, 2.3 h, 2.4 h, 2.5 h, 2.6 h, 2.7 h, 2.8 h, 2.9 h or 3.0 h. However, it is not limited to the listed values, and other unlisted values within this range are equally applicable.

[0073] In some alternative embodiments, the temperature for thermally induced cross-linking is 120 - 130 °C. For example, it can be 120 °C, 121 °C, 122 °C, 123 °C, 124 °C, 125 °C, 126 °C, 127 °C, 128 °C, 129 °C or 130 °C. However, it is not limited to the listed values, and other unlisted values within this range are equally applicable.

[0074] In some alternative embodiments, the time for thermally induced cross-linking is 2 - 3 h. For example, it can be 2.0 h, 2.1 h, 2.2 h, 2.3 h, 2.4 h, 2.5 h, 2.6 h, 2.7 h, 2.8 h, 2.9 h or 3.0 h. However, it is not limited to the listed values, and other unlisted values within this range are equally applicable.

[0075] In a second aspect, the present invention provides a sulfide-polymer composite solid electrolyte.

[0076] In the present invention, lithium sulfide and phosphorus pentasulfide are used as raw materials to form a sulfide precursor through the high-energy mechanical action of ball milling. During the ball milling process, high-energy impact and shear forces promote a mechanochemical reaction between lithium sulfide and phosphorus pentasulfide, generating a sulfide network structure. These sulfide materials exhibit excellent lithium-ion conductivity due to their unique structural characteristics. Their high lithium-ion diffusion coefficient and low ion migration activation energy make them an ideal component of solid electrolytes. In this process, the formation of the sulfide network provides a preliminary framework for the efficient migration of lithium ions.

[0077] Meanwhile, inorganic salts (lanthanum trichloride, gallium chloride, aluminum trichloride) partially enter the sulfide network through ion exchange or physical doping during the ball milling process. La 3 +、Ga 3High-valent metal ions such as + and Al3+ achieve local cation substitution by interacting with phosphorus or sulfur sites in sulfides, thereby introducing doping into the sulfide network. On the one hand, these doped ions break the original symmetry and form structural defects by changing the lattice parameters of sulfides. On the other hand, these defects can serve as "energy troughs" for lithium-ion migration, reducing the energy barrier in the lithium-ion diffusion path, thus effectively reducing the activation energy of lithium-ion diffusion. In addition, the introduction of doped ions also changes the local electric field distribution in sulfides, providing an additional electric field driving force, which helps the rapid diffusion of lithium ions in the network.

[0078] More importantly, the doped metal ions also play a "passivation" role on the surface of sulfide materials. Sulfide materials are usually highly sensitive to moisture and oxygen in the air and are prone to hydrolysis or oxidation reactions, resulting in a decrease in conductivity. However, through the interaction with surface sulfide groups, the doped ions can stabilize the surface chemical environment and reduce the activity of surface chemical reactions, thus significantly improving the environmental stability and long-term storage performance of sulfide precursors.

[0079] On this basis, through the heat treatment process, the solid-phase reaction between inorganic salts and sulfides further deepens, the distribution of doped ions becomes more uniform, and the doping effect is significantly improved. This uniformly distributed doping improves the overall electrochemical performance of the sulfide network, especially the uniformity of lithium-ion migration. At the same time, heat treatment may also induce the transformation of some sulfides from the amorphous state to the subcrystalline or microcrystalline state. During this transformation process, the local order inside the sulfides is enhanced, forming continuous lithium-ion migration channels, significantly optimizing the ionic conductivity of the material. In addition, the formation of the subcrystalline or microcrystalline state also helps to enhance the mechanical strength of the material, avoiding the mechanical fragility that may exist in completely amorphous materials. Therefore, heat treatment not only improves the chemical uniformity of doping but also further optimizes the conductivity and mechanical properties of sulfides through structural regulation, endowing the inorganic core with excellent ionic conductivity and structural stability.

[0080] At high temperatures, lithium sulfide and phosphorus pentasulfide are thoroughly mixed through a molten reaction and undergo a chemical reaction to form a high-purity glassy sulfide precursor. During this process, the high temperature provides sufficient thermal energy, causing the chemical bonds between lithium sulfide and phosphorus pentasulfide to break rapidly and reform into a sulfide network structure. The products generated from these reactions have a uniform chemical composition. However, due to rapid cooling, the material does not undergo a sufficient crystallization process and ultimately forms a completely amorphous glassy sulfide. The glassy sulfide exhibits a random ionic distribution, lacking the long-range ordered crystal arrangement, while retaining a large number of amorphous regions. These amorphous regions provide a significant advantage for the migration of lithium ions. Lithium ions can achieve rapid migration in the amorphous structure by dynamically coordinating and dissociating with polar groups in the amorphous network. The high degree of freedom of the amorphous structure gives the glassy sulfide a low ionic diffusion activation energy, enabling it to exhibit excellent performance in terms of ionic conductivity.

[0081] However, a completely amorphous glassy structure is not ideal for practical applications: Although the amorphous regions facilitate the migration of lithium ions, due to the lack of a regular crystal framework, such materials have relatively poor mechanical strength and may have limitations in terms of the uniformity of ionic migration and thermal stability. Therefore, through subsequent medium-temperature heat treatment, the glassy sulfide undergoes a partial crystallization process. During this process, the sulfide structure in local regions begins to transform from the amorphous state to the crystalline state, forming crystalline phase regions with a certain degree of order, while the uncrystallized part remains in the amorphous state, ultimately forming a composite structure in which the crystalline phase and the glass phase coexist. In this composite structure, the crystalline phase provides a stable framework, and its regular lattice arrangement provides a continuous and efficient channel for the migration of lithium ions, significantly enhancing the overall ionic conductivity of the material. At the same time, the presence of the crystalline structure enhances the mechanical strength and thermal stability of the material, avoiding the brittleness problem of glassy materials during use.

[0082] The glass phase plays an important supplementary role in the composite structure. Since the glassy regions retain the characteristics of amorphous materials, their high degree of freedom provides more migration paths for lithium ions and alleviates the possible interfacial impedance problems between the crystalline phases. In the composite material, the presence of the glass phase effectively improves the ionic transport continuity between the crystalline phases, ensuring the high-throughput migration of lithium ions throughout the material. In addition, the flexible characteristics of the glass phase alleviate the internal stress generated by volume changes during the electrochemical cycling process to a certain extent, thereby further enhancing the mechanical stability and long-term service life of the material. The synergistic effect of the crystalline phase and the glass phase enables the composite material to have both the high ionic conductivity of the crystalline phase and retain the flexible characteristics of the glass phase, ultimately achieving an optimized balance between ionic conductivity and mechanical properties.

[0083] In the present invention, an inorganic core is combined with an inorganic phase precursor, and the inorganic core plays an important role as a "seed" or "template" in this process. In the subsequent ball milling and heat treatment steps, the inorganic core induces the oriented crystallization of the inorganic phase precursor through its own crystal structure. This process of induced crystallization can be understood as a "heterogeneous nucleation" mechanism, in which the crystal planes of the inorganic core provide nucleation sites for the crystallization of the inorganic phase precursor. Compared with a coreless system, this nucleation method significantly reduces the nucleation energy barrier of the inorganic phase material, accelerates the crystallization process, and makes the crystallization more uniform and orderly. The introduction of this mechanism helps to avoid a large number of grain boundaries and structural defects that may occur during random crystallization, thereby improving the overall structural integrity of the composite material.

[0084] During the ball milling process, the inorganic core not only induces the oriented crystallization of the inorganic phase precursor through its crystal planes, but also further evenly disperses the inorganic phase precursor components under mechanical action to ensure sufficient contact between the two. The subsequent heat treatment step further promotes the crystallization of the inorganic phase precursor and strengthens the interfacial bonding between the inorganic core and the inorganic phase precursor. The finally formed composite inorganic phase is a multi-scale multiphase composite structure, combining the advantages of both crystalline and glassy phases. Specifically, the crystalline phase provides an efficient lithium-ion migration channel, and its regular crystal structure provides a stable path for the large-scale migration of lithium ions within the material; while the glassy phase provides a lower impedance for the lithium-ion transport at the interface through its amorphous regions, significantly enhancing the electrical conductivity of the material at the multiphase interface.

[0085] The formation of this multiphase composite structure not only improves the lithium-ion conductivity of the material, but also significantly improves its mechanical properties and cycling stability. On the one hand, the presence of the crystalline phase keeps the composite material with a high structural integrity during use, reducing structural damage caused by external stress or volume changes; on the other hand, the inorganic core as a seed effectively relieves the internal stress that may occur during the crystallization process through induced uniform crystallization, thereby enhancing the mechanical and thermal stability of the material. In addition, this multi-scale composite structure enables the material to form a continuous ion conduction network at different scales, further enhancing the diffusion ability of lithium ions.

[0086] The composite inorganic phase prepared in the present invention has been surface-modified in multiple stages to further improve its chemical stability, interfacial compatibility, and overall electrochemical performance. In the first-stage modification, indium trichloride and lithium chloride are selected as metal precursors. By dissolving them in absolute ethanol and adjusting the pH value of the solution, the uniform dispersion of metal cations (In3+, Li+) is achieved. The process of adjusting the pH is crucial for the stability of the precursor solution. An appropriate acidic environment can prevent the premature precipitation of metal ions and promote the uniform interaction between them and solvent molecules, forming a stable metal chloride precursor solution. This uniformly distributed solution lays the foundation for the subsequent coating process. On the surface of the composite inorganic phase, the metal chlorides in the precursor solution are uniformly distributed through deposition, gradually forming a dense and uniform coating layer. Subsequently, through moderate heat treatment, the coating layer solidifies and undergoes partial crystallization, finally forming an inorganic shell with high chemical stability.

[0087] The introduction of this coating layer significantly optimizes the material properties in multiple aspects. First, the coating layer effectively passivates the surface chemical activity of the sulfide composite inorganic phase. Sulfide materials are usually highly sensitive to moisture and oxygen in the air and are prone to hydrolysis or oxidation reactions, resulting in rapid deterioration of performance. By coating a dense metal chloride shell, the direct contact between the sulfide and the external environment can be effectively isolated, significantly improving the environmental stability and storage life of the material. Second, the coating layer reduces the interfacial impedance by optimizing the interfacial compatibility between the composite inorganic phase and the subsequent polymer matrix. This is because the introduction of the metal chloride layer can adjust the physicochemical properties of the inorganic phase surface, making it easier to form good interfacial contact with the polymer, thereby improving the conductivity and stability of the overall material.

[0088] Based on the first coating layer, the present invention further conducts a modification design for the second coating layer. In this stage, ammonium fluoride and lithium acetate react in absolute ethanol to generate a lithium fluoride precursor. On the surface of the composite inorganic phase, lithium fluoride is uniformly deposited on top of the first coating layer through chemical deposition, forming a second protective barrier. Subsequently, through moderate heat treatment, the lithium fluoride layer further solidifies and forms a stable structure. Lithium fluoride is a material with low electronic conductivity and high chemical stability, which plays a further chemical protection role in the coating system. Compared with the first coating layer, the lithium fluoride layer can more effectively resist the intrusion of moisture and oxygen in the environment and provide a stronger chemical isolation effect for the sulfide inorganic phase. Therefore, the introduction of the double-layer coating structure significantly improves the environmental stability and durability of the composite inorganic phase.

[0089] On the basis of double-layer coating, the present invention further introduces a conductive layer to improve the overall electrochemical performance of the material. Polyaniline is uniformly coated on the surface of the double-layer coated inorganic phase to form a conductive outer shell. Polyaniline is a conductive polymer with good electronic conductivity. The conjugated system in its structure allows electrons to move freely in the molecular chain, thus significantly improving the electron conduction ability of the composite material. The introduction of the polyaniline layer plays multiple roles in the composite inorganic phase: on the one hand, it provides an additional electron conduction path for the composite material, significantly reducing the interfacial impedance between the inorganic phase and the electrode; on the other hand, the flexibility and chemical stability of polyaniline can also enhance the structural stability of the material during cycling and improve the electrochemistry reaction kinetics during multiple charge and discharge processes. In addition, polyaniline can also interact with the inorganic phase and the electrolyte interface through the polar groups on its surface to further optimize the interfacial contact state.

[0090] The finally formed three-layer structure system, that is, the composite coating structure composed of the first layer of metal chloride, the second layer of lithium fluoride and the third layer of conductive polyaniline, exhibits significant performance advantages. The lithium fluoride layer, as the intermediate chemical protection barrier, provides excellent environmental stability and prevents the composite inorganic phase from being eroded by the outside world; while the polyaniline layer further optimizes the overall performance of the material by enhancing the electronic conductivity and interfacial electrochemical performance. The synergistic effect of this dual protection and the introduction of conductivity enables the composite inorganic phase to exhibit higher cycle stability and excellent electrochemical performance in the solid electrolyte system, ultimately providing a reliable material basis and solution for the application of high-performance solid-state lithium batteries.

[0091] In this study, in order to further optimize the performance of polyetheretherketone to meet the application requirements of solid electrolytes, it was modified in multiple steps, resulting in significant improvements in its ionic conductivity, flexibility and mechanical stability. First, sulfonic acid groups were introduced into the molecular backbone of polyetheretherketone through a sulfonation reaction. In this process, electrophilic substitution reactions occurred between the sulfonation reagent and the aromatic rings in polyetheretherketone to uniformly graft the sulfonic acid groups onto the polymer chains. Sulfonic acid groups have strong polarity and high lithium-ion affinity. Their introduction significantly enhances the interaction between the polymer and lithium ions, thus improving the migration ability of lithium ions. In addition, the presence of sulfonic acid groups also disrupts the regularity of the polyetheretherketone molecular chains, reduces the crystallinity of the polymer, and increases the proportion of amorphous regions. The amorphous regions provide more molecular degrees of freedom and form low-impedance paths for the migration of lithium ions in the polymer matrix, thus significantly improving the ionic conductivity of the material.

[0092] To further improve the flexibility and ion transport performance of the polymer, polyethylene glycol segments were introduced based on sulfonated polyether ether ketone. Polyethylene glycol is a flexible polymer, and its low glass transition temperature and the freedom of the polymer chains can significantly reduce the crystallinity of the polymer and further increase the proportion of the amorphous region. By means of chemical grafting or copolymerization, polyethylene glycol segments were introduced into the molecular backbone of sulfonated polyether ether ketone, which not only improved the flexibility and deformation ability of the polymer but also endued the material with higher ion migration ability. The ether oxygen groups in the polyethylene glycol segments can form dynamic coordination with lithium ions, further reducing the activation energy of lithium ion migration and thus accelerating the diffusion process of ions in the polymer.

[0093] On this basis, the overall performance of the material was further optimized by crosslinking. The crosslinking process introduced chemical bonds between polymer molecular chains through chemical reactions, constructing a three-dimensional network structure. While improving the mechanical properties of the film, this three-dimensional crosslinked network significantly enhanced the shape retention ability of the material, enabling it to resist the influence of external stress and volume changes during the electrochemical cycle. In addition, the introduction of the crosslinked structure can also limit the excessive movement of molecular segments, thus while ensuring the ion conduction performance, avoiding the problem of deformation failure caused by excessive softness of the material. The finally prepared polymer film not only exhibits excellent ion conductivity but also has high flexibility and excellent mechanical stability.

[0094] In this experimental scheme, a solid electrolyte system with excellent comprehensive performance was constructed by compounding the inorganic phase with the polymer matrix. The inorganic phase and the polymer matrix respectively perform different functions in the material, and the performance was synergistically enhanced through ingenious structural design. As the main component of the solid electrolyte, the inorganic phase has a high lithium ion mobility, and its partially crystallized structure provides regular and efficient lithium ion migration channels, significantly reducing the diffusion impedance of lithium ions in the solid electrolyte. At the same time, the remaining amorphous regions in the inorganic phase effectively alleviate the ion migration obstacles caused by the grain boundary effect and maintain the uniformity of the overall ion conduction of the material. In addition, the inorganic sulfide material provides a solid foundation for the composite electrolyte due to its unique chemical stability and high conductivity.

[0095] On the other hand, the polymer matrix provides mechanical support and flexible adjustment functions for the composite material by filling the gaps between the inorganic phases. The amorphous regions of the polymer serve as dynamic channels for lithium ion migration, which can not only form good interfacial contact with the inorganic phase but also flexibly fill the voids between the inorganic phases, thus avoiding the problem of ion migration impedance caused by interface discontinuity or physical defects. The presence of the polymer matrix also endows the composite electrolyte with excellent deformation ability and processing performance, enabling it to adapt to complex electrode structures. In addition, the chemical tunability of the polymer material also provides the possibility for further optimizing the interfacial compatibility and mechanical properties.

[0096] Through the organic combination of two materials, namely the inorganic phase and the polymer, a "bicontinuous ion-conducting network" structure is formed. In this network, the inorganic phase constructs the main lithium-ion migration channels through its highly conductive crystalline phase regions, while the polymer matrix connects and fills the interfacial regions of the inorganic phase through its flexible amorphous regions, forming a continuous and uniform ion migration path. The greatest advantage of the bicontinuous network structure is that the inorganic phase and the polymer phase respectively play their functional characteristics and achieve synergy at the interface. This design effectively avoids the interfacial instability and uneven ion migration problems that may exist in traditional composite electrolytes, thus significantly improving the overall electrochemical performance of the composite electrolyte.

[0097] During the preparation of the composite material, a thermal-initiated crosslinking process is further introduced to construct a three-dimensional network structure in the polymer matrix through chemical crosslinking reactions. The formation of the three-dimensional crosslinked network not only significantly enhances the mechanical strength and shape retention ability of the polymer matrix but also improves the interfacial bonding strength between the polymer and the inorganic phase. This three-dimensional network structure restricts the excessive movement of polymer segments, significantly enhancing the structural stability of the composite material while maintaining its flexibility. In addition, the presence of the crosslinked network can effectively inhibit the fluidity of the polymer under high-temperature or long-term operating conditions, thereby enhancing the thermal stability and cycle life of the composite electrolyte.

[0098] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0099] (1) Through the mechanochemical reaction of lithium sulfide and phosphorus pentasulfide, a partially crystallized sulfide network is generated, doped with high-valent metal ions to optimize the lattice structure, reduce the lithium-ion migration energy barrier, enhance conductivity and chemical stability. The crystalline phase provides efficient lithium-ion migration channels, and the amorphous regions reduce the grain boundary effect and improve the uniformity of ion conduction;

[0100] (2) The method of coating is adopted to improve the performance of the inorganic phase. The metal chloride and lithium fluoride coating layers isolate moisture and oxygen in the environment, greatly enhancing the environmental stability and durability of the composite inorganic phase; the coating of polyaniline significantly reduces the interfacial impedance of the inorganic phase, and at the same time, the flexibility and chemical stability of polyaniline can also enhance the structural stability of the material during the cycling process;

[0101] (3) Sulfonated polyether ether ketone introduces sulfonic acid groups to improve its lithiophilicity, reduce crystallinity and increase amorphous regions, providing a low-impedance path for lithium-ion migration. The polyethylene glycol segments enhance flexibility and ion migration ability, and crosslink to form a three-dimensional network structure, further enhancing mechanical strength and interfacial stability;

[0102] (4) The inorganic phase provides a main channel with high conductivity, and the polymer flexibly fills the gaps between the inorganic phases to form a bicontinuous ion-conducting network. The coating layer combines with the conductive polymer to reduce the interfacial impedance and optimize the ion transport path and interfacial chemical properties. The inorganic phase and the polymer act synergistically to improve the conductivity, mechanical properties, and cycling stability. Description of the Drawings

[0103] Figure 1 It is a flowchart of a preparation method of a sulfide-polymer composite solid electrolyte provided in Embodiment 1 of the present invention. Detailed Embodiments

[0104] The technical solution of the present invention will be described in detail below with reference to specific embodiments and their accompanying drawings. The embodiments described herein are specific specific embodiments of the present invention and are used to illustrate the concept of the present invention; these descriptions are all explanatory and exemplary and should not be construed as limiting the embodiments of the present invention and the protection scope of the present invention. Except for the embodiments described herein, those skilled in the art can also adopt other obvious technical solutions based on the content disclosed in the claims and the specification of the present application. These technical solutions include technical solutions that make any obvious substitutions and modifications to the embodiments described herein.

[0105] The chemical reagents used in the embodiments and comparative examples of the present invention are all commercially available products and have not been further purified or processed.

[0106] Embodiment 1

[0107] This embodiment provides a sulfide-polymer composite solid electrolyte and a preparation method thereof. The preparation method specifically includes the following steps:

[0108] S1: Heat-treat the mixed powder obtained by mixing and ball-milling the sulfide and the inorganic salt in an argon atmosphere to obtain an inorganic core body;

[0109] Specifically, in S1: Lithium sulfide and phosphorus pentasulfide are mixed and ball-milled with lanthanum trichloride, gallium chloride, and aluminum trichloride to obtain a mixed powder. The molar ratio of lithium sulfide to phosphorus pentasulfide is 7.6:3, and the molar ratio of the sulfide to the inorganic salt is 1:0.11. The mixed powder is heat-treated in an argon atmosphere to obtain an inorganic core body. The heating rate of the heat treatment is 8 °C / min, the temperature is 370 °C, and the time is 2.7 h.

[0110] S2: Heat-treat the molten and cooled lithium sulfide and phosphorus pentasulfide to obtain an inorganic phase precursor; mix the inorganic phase precursor with the inorganic core body and heat-treat to obtain a composite inorganic phase;

[0111] Specifically, in S2: Lithium sulfide and phosphorus pentasulfide are melted at a molar ratio of 2.4:1 in an argon atmosphere at a temperature of 580 °C for 18 min and then cooled to obtain a glassy precursor, which is heat-treated at 280 °C for 3 h to obtain an inorganic-phase precursor; The inorganic-phase precursor and the inorganic core are mixed and ball-milled at a mass ratio of 8.5:1 and then heat-treated at 340 °C for 1 h to obtain a composite inorganic phase;

[0112] S3: Indium trichloride and lithium chloride are dissolved in absolute ethanol, and acetic acid is added and then refluxed to obtain a precursor solution. The composite inorganic phase reacts with the precursor solution and is heat-treated to obtain a first coated inorganic phase;

[0113] Specifically, in S3: Indium trichloride and lithium chloride are dissolved in absolute ethanol at a molar ratio of 1:3, where the concentration of indium trichloride is 0.2 M, acetic acid is added to adjust the pH to 4.8, and refluxed at 55 °C for 2.7 h to obtain a precursor solution; The composite inorganic phase is dispersed in absolute ethanol at a mass fraction of 5.8 wt.% to obtain a composite inorganic-phase dispersion. The composite inorganic-phase dispersion is dropped into the precursor solution at a constant temperature of 67 °C and stirred for 4.5 h, where the mass ratio of the composite inorganic phase to the precursor solution is 1:10. After centrifugation, washing, and heat-treatment in an argon atmosphere at 270 °C for 2 h, a first coated inorganic phase is obtained;

[0114] S4: Ammonium fluoride and lithium acetate are dispersed in absolute ethanol to obtain a second precursor solution. The first coated inorganic phase reacts with the second precursor solution and is heat-treated to obtain a double-coated product; Polyaniline is compounded with the double-coated product to obtain a conductive-layer-coated inorganic phase;

[0115] Specifically, in S4: Ammonium fluoride and lithium acetate are dispersed in absolute ethanol to obtain a second precursor solution, where the concentration of ammonium fluoride is 0.28 mol / L and the concentration of ammonium fluoride is 0.28 mol / L; The first coated inorganic phase is dispersed in absolute ethanol at a mass fraction of 3.4 wt% to obtain dispersion A. The second precursor solution is dropped and stirred at 50 °C for 2 h, where the mass ratio of the first coated inorganic phase to the second precursor solution is 1:8. After centrifugation, washing, and heat-treatment in an argon atmosphere at 157 °C for 1 h, a double-coated inorganic phase is obtained; Polyaniline is dispersed in N-methylpyrrolidone at a mass fraction of 2.6 wt.% to obtain dispersion B. The double-coated inorganic phase is added to dispersion B and stirred at room temperature for 4.5 h, where the mass ratio of the double-coated inorganic phase to polyaniline is 97:3. After centrifugation, washing, and drying, a conductive-layer-coated inorganic phase is obtained.

[0116] S5: Polyetheretherketone is dispersed in concentrated sulfuric acid and reacted to obtain sulfonated polyetheretherketone, which is reacted with methoxypolyethylene glycol to obtain a modified polymer;

[0117] Specifically, S5: Polyether ether ketone was dispersed in concentrated sulfuric acid at a mass fraction of 4.8 wt.%, stirred at 40 °C for 10 h, and the reaction solution was slowly poured into ice water, filtered, washed, and dried in vacuo to obtain sulfonated polyether ether ketone; it was dispersed in N,N-dimethylformamide at a mass fraction of 13 wt.%, and a sodium hydroxide solution with a concentration of 1.6 M was added to adjust the pH to 8.7. A N,N-dimethylformamide solution of methoxypolyethylene glycol with a mass fraction of 17 wt.% was added dropwise, where the mass ratio of methoxypolyethylene glycol to sulfonated polyether ether ketone was 1.8:1, and the reaction was carried out at 70 °C for 22 h to obtain a reaction solution. The reaction solution was poured into deionized water, filtered, washed, and dried to obtain a modified polymer;

[0118] S6: The modified polymer was dispersed in N,N-dimethylformamide, and after adding an inorganic phase coated with a conductive layer, a crosslinking agent, an initiator, and a lithium salt, a homogeneous mixture was obtained, and a film was cast and crosslinked to obtain a composite solid electrolyte.

[0119] Specifically, S6: The modified polymer was dispersed in N,N-dimethylformamide at a mass fraction of 14 wt.%, and polyethylene glycol dimethacrylate and azobisisobutyronitrile were added, where the mass ratio of polyethylene glycol dimethacrylate to the modified polymer was 0.25:1 and the feeding amount of azobisisobutyronitrile was 0.1% of the mass of polyethylene glycol dimethacrylate, and ultrasonic dispersion was carried out to obtain a polymer solution; the inorganic phase coated with a conductive layer was dispersed in N,N-dimethylformamide at a mass fraction of 16 wt.%, the polymer solution was added, and then lithium perchlorate was added, and uniform dispersion was carried out to obtain a homogeneous mixture, where the concentration of lithium perchlorate in the homogeneous mixture was 0.2 M, and the mass ratio of the modified polymer to the inorganic phase coated with a conductive layer was 30:70. After casting into a film, it was pre-dried at 88 °C for 2.8 h and crosslinked by thermal initiation at 125 °C for 2.8 h, and dried in vacuo to obtain a sulfide-polymer composite solid electrolyte.

[0120] Example 2

[0121] This example provides a sulfide-polymer composite solid electrolyte and a preparation method thereof. The preparation method specifically includes the following steps:

[0122] S1: The mixed powder obtained by mixing and ball-milling sulfide and inorganic salt was heat-treated in an argon atmosphere to obtain an inorganic core body;

[0123] Specifically, S1: Lithium sulfide and phosphorus pentasulfide as sulfides were mixed and ball-milled with gallium chloride and aluminum trichloride to obtain a mixed powder, where the molar ratio of lithium sulfide to phosphorus pentasulfide was 8:3 and the molar ratio of sulfide to inorganic salt was 1:0.15; the mixed powder was heat-treated in an argon atmosphere to obtain an inorganic core body, where the heating rate of the heat treatment was 5 °C / min, the temperature was 400 °C, and the time was 2.3 h;

[0124] S2: After melting and cooling lithium sulfide and phosphorus pentasulfide, perform heat treatment to obtain an inorganic phase precursor; mix the inorganic phase precursor with an inorganic core and perform heat treatment to obtain a composite inorganic phase;

[0125] Specifically, S2: Melt lithium sulfide and phosphorus pentasulfide at a molar ratio of 2.3:1 in an argon atmosphere at a temperature of 590 °C for 15 min and then cool to obtain a glassy precursor, and perform heat treatment on it at 270 °C for 2.3 h to obtain an inorganic phase precursor; mix the inorganic phase precursor with an inorganic core at a mass ratio of 9:1, perform ball milling, and then perform heat treatment at 380 °C for 2 h to obtain a composite inorganic phase;

[0126] S3: Dissolve indium trichloride and lithium chloride in absolute ethanol, add acetic acid, and perform a reflux reaction to obtain a precursor solution. React the composite inorganic phase with the precursor solution and perform heat treatment to obtain a first coated inorganic phase;

[0127] Specifically, S3: Dissolve indium trichloride and lithium chloride at molar ratios of 1:3, 1:4, 1:3, 1:4 in absolute ethanol, where the concentration of indium trichloride is 0.2 M, 0.3 M, 0.1 M, 0.23 M, add acetic acid to adjust the pH to 4.8, 4.5, 4, 5, and perform a reflux at 55 °C, 60 °C, 50 °C, 58 °C for 2.7 h, 2.3 h, 2 h, 3 h to obtain a precursor solution; disperse the composite inorganic phase in absolute ethanol at a mass fraction of 5.6 wt.%, drop it into the precursor solution at a constant temperature of 63 °C and stir for 4.9 h, where the mass ratio of the composite inorganic phase to the precursor solution is 1:11, centrifuge, wash, and perform heat treatment at 280 °C in an argon atmosphere for 1.8 h to obtain a first coated inorganic phase;

[0128] S4: Disperse ammonium fluoride and lithium acetate in absolute ethanol to obtain a second precursor solution. React the first coated inorganic phase with the second precursor solution and perform heat treatment to obtain a double-layer coated product; compound polyaniline with the double-layer coated product to obtain a conductive layer-coated inorganic phase;

[0129] Specifically, S4: Ammonium fluoride and lithium acetate are dispersed in absolute ethanol to obtain a second precursor solution, where the concentration of ammonium fluoride is 0.24 mol / L and the concentration of ammonium fluoride is 0.24 mol / L; the first coated inorganic phase is dispersed in absolute ethanol at a mass fraction of 3.8 wt.% to obtain dispersion liquid A, the second precursor solution is added dropwise and stirred at 60 °C for 3 h, where the mass ratio of the first coated inorganic phase to the second precursor solution is 1:9, centrifuged, washed, and heat-treated at 156 °C for 2 h in an argon atmosphere to obtain a double-layer coated inorganic phase; polyaniline is dispersed in N-methylpyrrolidone at a mass fraction of 2.3 wt.% to obtain dispersion liquid B, the double-layer coated inorganic phase is added to dispersion liquid B and stirred at room temperature for 5 h, where the mass ratio of the double-layer coated inorganic phase to polyaniline is 96:4, centrifuged, washed, and dried to obtain a conductive layer-coated inorganic phase.

[0130] S5: Polyether ether ketone is dispersed in concentrated sulfuric acid to react to obtain sulfonated polyether ether ketone, and it is reacted with methoxypolyethylene glycol to obtain a modified polymer;

[0131] Specifically, S5: Polyether ether ketone is dispersed in concentrated sulfuric acid at a mass fraction of 4.5 wt.%, stirred at 50 °C for 12 h, the reaction solution is slowly poured into ice water, filtered, washed, and vacuum dried to obtain sulfonated polyether ether ketone; it is dispersed in N,N-dimethylformamide at a mass fraction of 14 wt.%, a sodium hydroxide solution with a concentration of 1.2 M is added to adjust the pH to 8.9, a N,N-dimethylformamide solution of methoxypolyethylene glycol with a mass fraction of 16 wt.% is added dropwise, where the mass ratio of methoxypolyethylene glycol to sulfonated polyether ether ketone is 2:1, reacted at 80 °C for 23 h to obtain a reaction solution, the reaction solution is poured into deionized water, filtered, washed, and dried to obtain a modified polymer;

[0132] S6: The modified polymer is dispersed in N,N-dimethylformamide, and after adding the conductive layer-coated inorganic phase, a cross-linking agent, an initiator, and a lithium salt, they are mixed to obtain a homogeneous mixed solution, which is cast into a film and cross-linked to obtain a composite solid electrolyte.

[0133] Specifically, S6: Disperse the modified polymer at a mass fraction of 15 wt.% in N,N-dimethylformamide, add polyethylene glycol dimethacrylate and azobisisobutyronitrile, where the mass ratio of polyethylene glycol dimethacrylate to the modified polymer is 0.28:1, and the feeding amount of azobisisobutyronitrile is 0.05% of the mass of polyethylene glycol dimethacrylate, and ultrasonically disperse to obtain a polymer solution; Disperse the inorganic phase coated with the conductive layer at a mass fraction of 18 wt.% in N,N-dimethylformamide, add the polymer solution, and then add lithium tetrafluoroborate, and uniformly disperse to obtain a uniformly mixed solution, where the concentration of lithium tetrafluoroborate in the uniformly mixed solution is 0.28 M, and the mass ratio of the modified polymer to the inorganic phase coated with the conductive layer is 35:65. After casting into a film, pre-dry at 84 °C for 2.3 h and thermally initiate cross-linking at 128 °C for 2.5 h, and vacuum dry to obtain a sulfide-polymer composite solid electrolyte.

[0134] Example 3

[0135] This example provides a sulfide-polymer composite solid electrolyte and a preparation method thereof. The preparation method specifically includes the following steps:

[0136] S1: Heat-treat the mixed powder obtained by mixing and ball-milling the sulfide and the inorganic salt in an argon atmosphere to obtain an inorganic core body;

[0137] Specifically, S1: Mix and ball-mill lithium sulfide and phosphorus pentasulfide as sulfides with lanthanum trichloride and aluminum trichloride to obtain a mixed powder, where the molar ratio of lithium sulfide to phosphorus pentasulfide is 7:3, and the molar ratio of the sulfide to the inorganic salt is 1:0.05; Heat-treat the mixed powder in an argon atmosphere to obtain an inorganic core body, where the heating rate of the heat treatment is 7 °C / min, the temperature is 300 °C, and the time is 2 h;

[0138] S2: Heat-treat the molten and cooled lithium sulfide and phosphorus pentasulfide to obtain an inorganic phase precursor; Mix and heat-treat the inorganic phase precursor and the inorganic core body to obtain a composite inorganic phase;

[0139] Specifically, S2: Melt lithium sulfide and phosphorus pentasulfide at a molar ratio of 2:1 in an argon atmosphere at 550 °C for 10 min and then cool to obtain a glassy precursor, and heat-treat it at 250 °C for 2 h to obtain an inorganic phase precursor; Mix the inorganic phase precursor and the inorganic core body at a mass ratio of 8:1, ball-mill them, and then heat-treat them at 300 °C for 1.8 h to obtain a composite inorganic phase;

[0140] S3: Dissolve indium trichloride and lithium chloride in absolute ethanol, add acetic acid, and reflux to react to obtain a precursor solution. React the composite inorganic phase with the precursor solution and heat-treat to obtain a first coated inorganic phase;

[0141] Specifically, S3: Dissolve indium trichloride and lithium chloride in anhydrous ethanol at a molar ratio of 1:3, where the concentration of indium trichloride is 0.1 M. Adjust the pH to 4 with acetic acid and reflux at 50 °C for 2 h to obtain a precursor solution; Disperse the composite inorganic phase in anhydrous ethanol at a mass fraction of 5 wt.% to obtain a composite inorganic phase dispersion. Dropwise add the precursor solution at a constant temperature of 60 °C and stir for 4 h, where the mass ratio of the composite inorganic phase to the precursor solution is 1:8. Centrifuge, wash, and heat-treat at 250 °C for 1.2 h in an argon atmosphere to obtain the first coated inorganic phase;

[0142] S4: Disperse ammonium fluoride and lithium acetate in anhydrous ethanol to obtain a second precursor solution. React the first coated inorganic phase with the second precursor solution and perform heat treatment to obtain a double-layer coated product; Composite polyaniline with the double-layer coated product to obtain a conductive layer-coated inorganic phase;

[0143] Specifically, S4: Disperse ammonium fluoride and lithium acetate in anhydrous ethanol to obtain a second precursor solution, where the concentration of ammonium fluoride is 0.2 mol / L and the concentration of ammonium fluoride is 0.2 mol / L; Disperse the first coated inorganic phase in anhydrous ethanol at a mass fraction of 4 wt.% to obtain dispersion A. Dropwise add the second precursor solution and stir at 58 °C for 2.7 h, where the mass ratio of the first coated inorganic phase to the second precursor solution is 1:6. Centrifuge, wash, and heat-treat at 150 °C for 1.7 h in an argon atmosphere to obtain the double-layer coated inorganic phase; Disperse polyaniline in N-methylpyrrolidone at a mass fraction of 2 wt.% to obtain dispersion B. Add the double-layer coated inorganic phase to dispersion B and stir at room temperature for 5 h, where the mass ratio of the double-layer coated inorganic phase to polyaniline is 95:5. Centrifuge, wash, and dry to obtain the conductive layer-coated inorganic phase.

[0144] S5: Disperse polyetheretherketone in concentrated sulfuric acid to react to obtain sulfonated polyetheretherketone, and react it with methoxypolyethylene glycol to obtain a modified polymer;

[0145] Specifically, S5: Disperse polyetheretherketone in concentrated sulfuric acid at a mass fraction of 4 wt.%, stir at 47 °C for 11 h, slowly pour the reaction solution into ice water, filter, wash, and vacuum dry to obtain sulfonated polyetheretherketone; Disperse it in N,N-dimethylformamide at a mass fraction of 10 wt.%, add a sodium hydroxide solution with a concentration of 1 M to adjust the pH to 8, dropwise add an N,N-dimethylformamide solution of methoxypolyethylene glycol with a mass fraction of 15 wt.%, where the mass ratio of methoxypolyethylene glycol to sulfonated polyetheretherketone is 1:1, react at 77 °C for 20 h to obtain a reaction solution, pour the reaction solution into deionized water, filter, wash, and dry to obtain the modified polymer;

[0146] S6: Disperse the modified polymer in N,N-dimethylformamide, add the conductive layer-coated inorganic phase, crosslinking agent, initiator and lithium salt, and then mix to obtain a homogeneous mixture, and cast and crosslink the film to obtain a composite solid electrolyte.

[0147] Specifically, in S6: Disperse the modified polymer in N,N-dimethylformamide at a mass fraction of 10 wt.%, add polyethylene glycol dimethacrylate and azobisisobutyronitrile, where the mass ratio of polyethylene glycol dimethacrylate to the modified polymer is 0.2:1, and the feeding amount of azobisisobutyronitrile is 0.12% of the mass of polyethylene glycol dimethacrylate, and ultrasonically disperse to obtain a polymer solution; Disperse the conductive layer-coated inorganic phase in N,N-dimethylformamide at a mass fraction of 15 wt.%, add the polymer solution, and then add lithium perchlorate, and uniformly disperse to obtain a homogeneous mixture, where the concentration of lithium perchlorate in the homogeneous mixture is 0.1 M, and the mass ratio of the modified polymer to the conductive-coated inorganic phase is 20:80. After casting the film, pre-dry it at 80 °C for 2 h and crosslink it by thermal initiation at 120 °C for 2 h, and vacuum dry to obtain a sulfide-polymer composite solid electrolyte.

[0148] Example 4

[0149] This example provides a sulfide-polymer composite solid electrolyte and a preparation method thereof. The preparation method specifically includes the following steps:

[0150] S1: Heat-treat the mixed powder obtained by mixing sulfide and inorganic salt by ball milling in an argon atmosphere to obtain an inorganic core body;

[0151] Specifically, in S1: Mix lithium sulfide and phosphorus pentasulfide as sulfide with lanthanum trichloride and gallium chloride by ball milling to obtain a mixed powder, where the molar ratio of lithium sulfide to phosphorus pentasulfide is 7.8:3, and the molar ratio of sulfide to inorganic salt is 1:0.13; Heat-treat the mixed powder in an argon atmosphere to obtain an inorganic core body, where the heating rate of the heat treatment is 10 °C / min, the temperature is 340 °C, and the time is 3 h;

[0152] S2: Melt and cool lithium sulfide and phosphorus pentasulfide, and then heat-treat to obtain an inorganic phase precursor; Mix the inorganic phase precursor and the inorganic core body and heat-treat to obtain a composite inorganic phase;

[0153] Specifically, in S2: Melt lithium sulfide and phosphorus pentasulfide at a molar ratio of 2.5:1 in an argon atmosphere at 600 °C for 20 min and then cool to obtain a glassy precursor, and heat-treat it at 300 °C for 2.9 h to obtain an inorganic phase precursor; Mix the inorganic phase precursor and the inorganic core body at a mass ratio of 8.9:1 by ball milling and then heat-treat at 400 °C for 1.2 h to obtain a composite inorganic phase;

[0154] S3: Dissolve indium trichloride and lithium chloride in absolute ethanol, add acetic acid, and reflux to react to obtain a precursor solution. React the composite inorganic phase with the precursor solution and perform heat treatment to obtain the first coated inorganic phase;

[0155] Specifically, S3: Dissolve indium trichloride and lithium chloride in absolute ethanol at a molar ratio of 1:4, where the concentration of indium trichloride is 0.23 M. Add acetic acid to adjust the pH to 5, and reflux at 58 °C for 3 h to obtain a precursor solution; Disperse the composite inorganic phase in absolute ethanol at a mass fraction of 6 wt.% to obtain a composite inorganic phase dispersion. Dropwise add the precursor solution at a constant temperature of 70 °C and stir for 5 h, where the mass ratio of the composite inorganic phase to the precursor solution is 1:12. Centrifuge, wash, and perform heat treatment at 300 °C for 1 h in an argon atmosphere to obtain the first coated inorganic phase;

[0156] S4: Disperse ammonium fluoride and lithium acetate in absolute ethanol to obtain a second precursor solution. React the first coated inorganic phase with the second precursor solution and perform heat treatment to obtain a double-layer coated product; Composite polyaniline with the double-layer coated product to obtain a conductive layer-coated inorganic phase;

[0157] Specifically, S4: Disperse ammonium fluoride and lithium acetate in absolute ethanol to obtain a second precursor solution, where the concentration of ammonium fluoride is 0.3 mol / L and the concentration of ammonium fluoride is 0.3 mol / L; Disperse the first coated inorganic phase in absolute ethanol at a mass fraction of 3 wt.% to obtain dispersion A. Dropwise add the second precursor solution and stir at 56 °C for 2.3 h, where the mass ratio of the first coated inorganic phase to the second precursor solution is 1:10. Centrifuge, wash, and perform heat treatment at 160 °C for 1.2 h in an argon atmosphere to obtain a double-layer coated inorganic phase; Disperse polyaniline in N-methylpyrrolidone at a mass fraction of 3 wt.% to obtain dispersion B. Add the double-layer coated inorganic phase to dispersion B and stir at room temperature for 4.9 h, where the mass ratio of the double-layer coated inorganic phase to polyaniline is 98:2. Centrifuge, wash, and dry to obtain a conductive layer-coated inorganic phase.

[0158] S5: Disperse polyetheretherketone in concentrated sulfuric acid to react to obtain sulfonated polyetheretherketone, and react it with methoxypolyethylene glycol to obtain a modified polymer;

[0159] Specifically, S5: Polyether ether ketone is dispersed in concentrated sulfuric acid at a mass fraction of 5 wt.%, stirred at 45 °C for 11.2 h, the reaction solution is slowly poured into ice water, filtered, washed, and dried under vacuum to obtain sulfonated polyether ether ketone; it is dispersed in N,N-dimethylformamide at a mass fraction of 15 wt.%, the pH is adjusted to 9 by adding a sodium hydroxide solution with a concentration of 2 M, and a N,N-dimethylformamide solution of methoxypolyethylene glycol with a mass fraction of 20 wt.% is added, where the mass ratio of methoxypolyethylene glycol to sulfonated polyether ether ketone is 1.6:1, reacted at 78 °C for 24 h to obtain a reaction solution, and the reaction solution is poured into deionized water, filtered, washed, and dried to obtain a modified polymer;

[0160] S6: The modified polymer is dispersed in N,N-dimethylformamide, and after adding an inorganic phase coated with a conductive layer, a crosslinking agent, an initiator, and a lithium salt, they are mixed to obtain a homogeneous mixture, which is cast into a film and crosslinked to obtain a composite solid electrolyte.

[0161] Specifically, S6: The modified polymer is dispersed in N,N-dimethylformamide at a mass fraction of 12 wt.%, polyethylene glycol dimethacrylate and azobisisobutyronitrile are added, where the mass ratio of polyethylene glycol dimethacrylate to the modified polymer is 0.3:1, and the feeding amount of azobisisobutyronitrile is 0.15% of the mass of polyethylene glycol dimethacrylate, and ultrasonic dispersion is carried out to obtain a polymer solution; the inorganic phase coated with a conductive layer is dispersed in N,N-dimethylformamide at a mass fraction of 20 wt.%, the polymer solution is added, and then lithium tetrafluoroborate is added, and uniform dispersion is carried out to obtain a homogeneous mixture, where the concentration of lithium tetrafluoroborate in the homogeneous mixture is 0.3 M, and the mass ratio of the modified polymer to the inorganic phase coated with a conductive layer is 40:60. After casting into a film, it is pre-dried at 90 °C for 3 h and thermally crosslinked at 130 °C for 3 h, and dried under vacuum to obtain a sulfide-polymer composite solid electrolyte.

[0162] Comparative Example 1

[0163] This comparative example provides a sulfide-polymer composite solid electrolyte. The difference from Example 1 is that in S2, the mass ratio of the inorganic phase precursor to the inorganic core is 10:1, and the other operation steps and process parameters are exactly the same as those in Example 1.

[0164] Comparative Example 2

[0165] This comparative example provides a sulfide-polymer composite solid electrolyte. The difference from Example 1 is that in S2, the mass ratio of the inorganic phase precursor to the inorganic core is 5:1, and the other operation steps and process parameters are exactly the same as those in Example 1.

[0166] Comparative Example 3

[0167] This comparative example provides a sulfide-polymer composite solid electrolyte, which is different from Example 1 in that in S4, the mass ratio of the double-layer coated inorganic phase to polyaniline is 92:8, and the other operation steps and process parameters are exactly the same as those in Example 1.

[0168] Comparative Example 4

[0169] This comparative example provides a sulfide-polymer composite solid electrolyte, which is different from Example 1 in that in S4, the mass ratio of the double-layer coated inorganic phase to polyaniline is 99:1, and the other operation steps and process parameters are exactly the same as those in Example 1.

[0170] Comparative Example 5

[0171] This comparative example provides a sulfide-polymer composite solid electrolyte, which is different from Example 1 in that in S5, the mass ratio of methoxypolyethylene glycol to sulfonated polyether ether ketone is 5:1, and the other operation steps and process parameters are exactly the same as those in Example 1.

[0172] Comparative Example 6

[0173] This comparative example provides a sulfide-polymer composite solid electrolyte, which is different from Example 1 in that in S5, the mass ratio of methoxypolyethylene glycol to sulfonated polyether ether ketone is 0.1:1, and the other operation steps and process parameters are exactly the same as those in Example 1.

[0174] Perform performance tests on the sulfide-polymer composite solid electrolytes of the above Examples 1-4 and Comparative Examples 1-6. The specific process is as follows:

[0175] Ionic conductivity: The sample is sliced under an argon atmosphere, and the ionic conductivity is tested by an impedance analyzer using a die cell experiment. The test conditions are: test pressure 200 MPa, frequency 35 MHz - 0.1 Hz;

[0176] Tensile strength: Tested using a battery separator tensile strength tester.

[0177] The test results are shown in Table 1.

[0178] Table 1: Performance test results of the sulfide-polymer composite solid electrolytes of Examples 1-4 and Comparative Examples 1-6

[0179]

[0180]

[0181] From the test results of Example 1, Comparative Example 1, and Comparative Example 2, it can be seen that when the content of the inorganic phase precursor is too high, the proportion of the amorphous region in the composite inorganic phase increases, which may lead to insufficient effective connectivity of the crystalline phase conductive channels, thereby reducing the ionic conductivity. In addition, the excess of the inorganic phase may lead to poor interfacial bonding between particles, resulting in a decrease in the mechanical properties of the material and a weakening of the tensile strength. When the content of the inorganic core is too high, the proportion of the crystalline phase in the composite inorganic phase will be too high. Although it can provide more highly conductive channels, the insufficient amorphous region will limit the uniform distribution and diffusion of lithium ions. At the same time, too many rigid crystalline phases will reduce the tensile strength of the material.

[0182] From the test results of Example 1, Comparative Example 3, and Comparative Example 4, it can be seen that the excess of polyaniline may lead to the formation of a relatively thick conductive layer on the surface of the electrolyte. Although this helps to reduce the interfacial impedance, it will hinder the effective migration of lithium ions and reduce the ionic conductivity. In addition, too much polyaniline will reduce the overall mechanical strength of the material because polyaniline has high flexibility and is difficult to provide sufficient support. When the content of polyaniline is insufficient, the conductive layer cannot fully cover the double-layer coated inorganic phase, the interfacial impedance increases, and the migration efficiency of lithium ions at the interface decreases, resulting in a decrease in ionic conductivity. In addition, the deficiency of polyaniline may lead to interfacial chemical instability and affect the mechanical properties during long-term cycling.

[0183] From the test results of Example 1, Comparative Example 5, and Comparative Example 6, it can be seen that too much methoxypolyethylene glycol will introduce too many flexible chain segments. Although this helps to improve the ionic migration ability, it will significantly reduce the mechanical strength of the composite material, resulting in a decrease in tensile strength. In addition, the excess of flexible chain segments may lead to a decrease in the structural stability of the material and affect the cycle life. When the content of methoxypolyethylene glycol is insufficient, the flexibility and the proportion of the amorphous region of the polymer will decrease, the lithium ion migration path will be reduced, resulting in a decrease in ionic conductivity. At the same time, the brittleness of the material increases, which may lead to a decrease in tensile strength.

[0184] The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention fall within the protection scope and the disclosure scope of the present invention.

Claims

1. A preparation method of a sulfide-polymer composite solid electrolyte, characterized in that, The preparation method includes: S1: Heat-treating the mixed powder obtained by mixing sulfide and inorganic salt by ball milling under an argon atmosphere to obtain an inorganic core; S2: Melting and cooling lithium sulfide and phosphorus pentasulfide and then heat-treating to obtain an inorganic phase precursor; mixing the inorganic phase precursor and the inorganic core and heat-treating to obtain a composite inorganic phase; S3: Dissolving indium trichloride and lithium chloride in absolute ethanol, adding acetic acid and then refluxing to react to obtain a precursor solution, reacting the composite inorganic phase with the precursor solution, and heat-treating to obtain a first coated inorganic phase; S4: Dispersing ammonium fluoride and lithium acetate in absolute ethanol to obtain a second precursor solution, reacting the first coated inorganic phase with the second precursor solution and heat-treating to obtain a double-layer coated product; compounding polyaniline with the double-layer coated product to obtain a conductive layer-coated inorganic phase; S5: Disperse polyetheretherketone in concentrated sulfuric acid and react to obtain sulfonated polyetheretherketone, and react it with methoxypolyethylene glycol to obtain a modified polymer; S6: Disperse the modified polymer in N,N-dimethylformamide, add the conductive layer-coated inorganic phase, a crosslinking agent, an initiator and a lithium salt, and then mix to obtain a homogeneous mixture, and cast and crosslink into a composite solid electrolyte; In S1: The sulfide is lithium sulfide and phosphorus pentasulfide, and the molar ratio of lithium sulfide to phosphorus pentasulfide is 7-8:3; The inorganic salt is any one or a combination of at least two of lanthanum trichloride, gallium chloride, and aluminum trichloride.

2. The preparation method of a sulfide-polymer composite solid electrolyte according to claim 1, characterized in that In S1: The molar ratio of the sulfide to the inorganic salt is 1:0.05-0.

15.

3. A preparation method of a sulfide-polymer composite solid electrolyte according to claim 1, characterized in that, In S2: The molar ratio of lithium sulfide to phosphorus pentasulfide is 2-2.5:1; The mass ratio of the inorganic phase precursor to the inorganic core is 8-9:

1.

4. A preparation method of a sulfide-polymer composite solid electrolyte according to claim 1, characterized in that In S3: The molar ratio of indium trichloride to lithium chloride is 1:2-3; The concentration of indium trichloride in absolute ethanol is 0.1-0.3M; Add acetic acid to adjust the pH to 4-5; The mass ratio of the composite inorganic phase to the precursor solution is 1:8-12.

5. A preparation method of a sulfide-polymer composite solid electrolyte according to claim 1, characterized in that In S4: The concentration of ammonium fluoride dispersed in absolute ethanol is 0.2-0.3mol / L; The concentration of lithium acetate dispersed in absolute ethanol is 0.2-0.3mol / L; The mass ratio of the first coated inorganic phase to the second precursor solution is 1:6-10; The mass ratio of the double-layer coated inorganic phase to polyaniline is 95:5-98:

2.

6. The preparation method of a sulfide-polymer composite solid electrolyte according to claim 1, characterized in that, In S5: The mass fraction of polyetheretherketone in concentrated sulfuric acid is 4-5wt.%; The mass ratio of methoxypolyethylene glycol to sulfonated polyetheretherketone is 1-2:

1.

7. A preparation method of a sulfide-polymer composite solid electrolyte according to claim 1, characterized in that, In S6: The mass fraction of the modified polymer in N,N-dimethylformamide is 10-15wt.%; The crosslinking agent is polyethylene glycol dimethacrylate, and the mass ratio of the crosslinking agent to the modified polymer is 0.2-0.3:

1.

8. A preparation method of a sulfide-polymer composite solid electrolyte according to claim 1, characterized in that, In S6: The initiator is azobisisobutyronitrile, and the feeding amount of the initiator is 0.5-0.15% of the mass of the crosslinking agent; The lithium salt is any one or a combination of two of lithium perchlorate and lithium tetrafluoroborate; The concentration of the lithium salt in the homogeneous mixture is 0.1-0.3M.

9. The preparation method of a sulfide-polymer composite solid electrolyte according to claim 1, characterized in that, In S6: The mass ratio of the modified polymer to the inorganic phase coated with the conductive layer is (20 - 40):(60 - 80).

10. A sulfide-polymer composite solid electrolyte is prepared by using the preparation method according to any one of claims 1 - 9.

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