Method for batch production of a series of sulfide fast ionic conductors and applications

Abstract

The application discloses a method for batch preparation of a series of sulfide fast ion conductors and application of the sulfide fast ion conductors in all-solid-state lithium batteries. The synthesis procedure comprises the following steps: liquid phase mixing and pre-reaction, wherein Li2S, P2S5 and SiS2 are mixed and reacted in an organic solvent, the solvent in the mixed solution after the reaction is removed by normal pressure and vacuum drying to obtain a precursor; and the precursor is heated and treated under the condition of 400-700 DEG C to obtain the sulfide fast ion conductor. The general formula of the prepared series of sulfide fast ion conductors is xLi3PS4-(1-x)Li4SiS4. The method can realize the scale preparation of the sulfide fast ion conductor. The sulfide fast ion conductor has high ion conductivity, and the all-solid-state lithium battery assembled by using the sulfide fast ion conductor has the advantages of cycle stability, high charge-discharge specific capacity and excellent safety.

Description

Technical Field

[0001] This invention relates to the field of solid electrolyte materials for lithium-ion batteries, and in particular to a method for the large-scale preparation of a series of sulfide fast ion conductors and their application in all-solid-state lithium batteries. Background Technology

[0002] The development of next-generation energy storage systems is of great significance to global carbon dioxide emission reduction and energy structure adjustment. Currently, lithium-ion batteries are widely used in electric vehicles, mobile phones, and other electronic products due to their high energy density and lack of memory effect. However, the organic electrolytes used in traditional lithium-ion batteries are volatile and flammable, making them prone to combustion and explosion during battery leakage, overcharging, and over-discharging. Therefore, the demand for developing safer energy storage systems with high energy density is growing. All-solid-state lithium batteries use non-flammable solid electrolytes instead of organic electrolytes and separators, fundamentally avoiding the safety risks associated with conventional lithium-ion batteries. Currently, all-solid-state lithium batteries are recognized as the most promising next-generation energy storage system.

[0003] Solid-state electrolytes used in all-solid-state lithium batteries can be mainly divided into two types: inorganic solid-state electrolytes and polymer solid-state electrolytes. Inorganic solid-state electrolytes can be further subdivided into sulfide solid-state electrolytes, oxide solid-state electrolytes, and halide solid-state electrolytes. Among them, sulfide solid-state electrolytes have attracted much attention in the industry due to their ionic conductivity comparable to liquid electrolytes and their ease of cold pressing. However, the classic synthesis method of sulfide solid-state electrolytes relies on mechanical ball milling for mixing and pre-reaction followed by sintering, which is highly dependent on equipment, consumes a lot of energy, and is difficult to mass-produce. Liquid-phase mixing and pre-reaction significantly reduce the equipment cost in the sulfide preparation process; at the same time, using the liquid-phase method to replace the mechanical ball milling method as the mixing and pre-reaction method can achieve the mass production of sulfides at the kilogram or even ton level. However, in the past, Li3PS4 and Li7P3S synthesized using the liquid-phase method as the mixing and pre-reaction method... 11 The ionic conductivity of sulfide solid electrolytes is relatively low, which cannot meet the requirements of industrial production. Therefore, developing a method for the large-scale preparation of sulfide fast ion conductors is of great significance for the universality and commercialization of sulfide-based all-solid-state batteries. Summary of the Invention

[0004] The purpose of this invention is to provide a method for the large-scale preparation of a series of sulfide fast ion conductors and their application in solid-state lithium batteries. This preparation method enables the large-scale preparation of sulfide fast ion conductors with high ionic conductivity. All-solid-state lithium metal batteries assembled with these scalably prepared sulfide fast ion conductors exhibit excellent cycle performance and high charge-discharge specific capacity.

[0005] A series of sulfide fast ion conductor materials are disclosed, with the general chemical formula: xLi3PS4-(1-x)Li4SiS4, where 0.5 ≤ x < 1. Specifically, the prepared series of sulfide fast ion conductor crystal structures have: octahedrons composed of Li and S elements; PS4 tetrahedrons and SiS4 tetrahedrons composed of P and Si elements respectively with S elements, with the octahedrons sharing vertices or edges with the two tetrahedrons. When 0.5 ≤ x ≤ 0.6, the prepared sulfide fast ion conductors are tetragonal crystals with the P42 / nmc space group, and their cold-pressed powder ionic conductivity is 1-3 mS / cm. -1 The ionic conductivity of the annealed and sintered ceramic sheets is 3-7 mS / cm. -1 When 0.6 < x < 0.75, the sulfide fast ion conductor is a two-phase mixture of tetragonal (P42 / nmc space group) and orthorhombic (Pnma space group), and its cold-pressed powder ion conductor has a conductivity of 2-5 mS / cm. -1 When 0.75 ≤ x < 1, the prepared sulfide fast ion conductor belongs to the orthorhombic crystal system and Pnma space group, and its cold-pressed powder ion conductor has a conductivity of 0.5-2 mS / cm. -1 .

[0006] A method for batch preparation of a series of sulfide fast ion conductors includes the following steps:

[0007] Step 1: Under conditions of 10–100℃, Li₂S, P₂S₅, and SiS₂ are mixed and stirred in an organic solvent for 72–168 hours to prepare a homogeneous emulsion.

[0008] Step 2: At 50-120℃, the homogeneous emulsion is stirred to remove the solvent, thereby obtaining a homogeneous sulfide precursor.

[0009] Step 3: Under vacuum conditions of 10–1 Pa and at 100–140 °C, the solvent in the obtained homogeneous sulfide precursor is further removed to obtain the precursor;

[0010] Step 4: The precursor obtained in Step 3 is subjected to heating and sintering treatment in an inert gas atmosphere at 400-700℃ to obtain a series of sulfide fast ion conductors. The general formula of the series of sulfide fast ion conductors is xLi3PS4-(1-x)Li4SiS4, where 0.5≤x<1.

[0011] Further preferred, the method for large-scale preparation of a series of sulfide fast ion conductors includes the following steps:

[0012] (1) Liquid phase mixing and pre-reaction process: Under conditions above room temperature and below 100℃, in a dry atmosphere or under inert gas protection, Li2S, P2S5 and SiS2 are mixed in an organic solvent in molar stoichiometric ratio according to the corresponding value of x in the general formula xLi3PS4-(1-x)Li4SiS4. The mixture is then subjected to vigorous magnetic or mechanical stirring at a speed of 100-1500 rpm for 72-168 hours, thereby preparing a uniform emulsion. Where 0.5≤x<1;

[0013] (2) Atmospheric pressure drying process: at 50-120°C, under the protection of an inert gas atmosphere, the above-reacted mixed solution is mechanically stirred or magnetically stirred at a speed of 100-1200 rpm to remove the solvent, and a slightly yellow homogeneous sulfide precursor is obtained.

[0014] (3) Vacuum drying process: under vacuum conditions of 10 to 0.1 Pa and at 100 to 140 °C, the solvent in the obtained sulfide precursor is further removed;

[0015] (4) Heating and sintering process: The sulfide precursor obtained in step 3 is placed in a sealed container, and the container is placed in a muffle furnace. Heating and sintering treatment is carried out in an inert gas atmosphere. The heating program is adjusted to 1-20℃ / min, the temperature is raised to 400-700℃, and the temperature is held for 2-96h. The temperature is then naturally cooled to room temperature to obtain a series of sulfide fast ion conductors.

[0016] The following are preferred technical solutions of the present invention:

[0017] In step (1), the heating temperature in the liquid phase mixing and pre-reaction process is 25-80℃; the dew point of the dry atmosphere should be less than -20℃; the inert gas is one of nitrogen and argon, preferably argon; the organic solvent is one of anhydrous acetonitrile, tetrahydrofuran, and oxadionitrile, preferably acetonitrile; the stirring speed is preferably 300-800 rpm; and the reaction time is preferably 80-150 h.

[0018] In step (2), the drying temperature is preferably 80-120℃; the inert gas is either nitrogen or argon, preferably argon; and the speed of the mechanical or magnetic stirring is preferably 100-700 rpm.

[0019] In step (3), the vacuum condition is preferably 10 to 1 Pa; the vacuum drying temperature is preferably 100-120°C.

[0020] In step (4), the inert gas is either argon or nitrogen, preferably nitrogen; the heating rate is preferably 5-20℃ / min; the holding temperature is preferably 450-600℃; and the holding time is preferably 10-50h.

[0021] The application of the prepared series of sulfide fast ion conductors in all-solid-state lithium batteries specifically includes:

[0022] The prepared series of sulfide fast ion conductors, positive electrode active material powders (including but not limited to NMC811, NMC622, NMC111, LiCoO2, etc.) and acetylene black are mixed evenly in a ratio of 15-35:85-65:0-2; after mixing evenly, 0.1-3 wt% polytetrafluoroethylene binder is added and shear force is applied to prepare a composite positive electrode film.

[0023] The prepared series of sulfide fast ion conductors and polytetrafluoroethylene binders were mixed and ground in a ratio of 100:0.5 to 2 and shear force was applied to prepare an electrolyte film with a thickness of about 0.035 to 0.3 mm.

[0024] A solid-state lithium battery was fabricated by stacking a Li-In alloy with a lithium metal mass fraction of 0–4 wt% as the negative electrode material with an electrolyte film and a composite positive electrode film.

[0025] Compared with the prior art, the present invention has the following advantages:

[0026] I. The precursor of sulfide fast ion conductors is obtained by liquid-phase mixing pre-reaction. Compared with the traditional ball milling mixing method, the time and energy consumption of the pre-reaction are reduced, and the sulfide fast ion conductors can be produced in a planned manner in a short time.

[0027] Second, by using a combination of drying and vacuum drying, residual solvents in the reaction system were removed, resulting in a series of tightly bonded sulfide precursor powders. These sulfide precursor powders exhibit high ionic conductivity after the sintering process, and their ionic conductivity is not significantly different from that of the corresponding fast ionic conductors of sulfides produced by conventional ball milling and sintering.

[0028] Third, the developed series of sulfide fast ion conductor materials exhibit different lithium transport behaviors and physicochemical properties due to variations in silicon content within the system. The series of sulfide fast ion conductors with different compositions, prepared in batches, are suitable for various all-solid-state lithium battery applications.

[0029] IV. The all-solid-state lithium batteries assembled using the series of sulfide fast ion conductors developed in this invention have the characteristics of excellent cycle performance, high charge-discharge specific capacity, and good safety. Attached Figure Description

[0030] Figure 1 The XRD pattern of the sulfide fast ion conductor with space group P42 / nmc prepared in Example 1.

[0031] Figure 2 The AC impedance diagram is shown for a blocking cell based on a sulfide fast ion conductor with space group P42 / nmc, prepared in Example 1.

[0032] Figure 3 The XRD pattern of the fast ion conductor of sulfide with space group Pnma prepared in Example 2.

[0033] Figure 4 AC impedance diagram of a blocking cell with a Pnma space group sulfide fast ion conductor prepared based on Example 2;

[0034] Figure 5 The XRD pattern of the sulfide fast ion conductor prepared in Example 3, which is a mixture of two phases of space group P42 / nmc and space group Pnma.

[0035] Figure 6 The AC impedance diagram is for a blocking cell based on a sulfide fast ion conductor with a two-phase mixture of P42 / nmc and Pnma space groups prepared in Example 3. Detailed Implementation

[0036] The present invention will be described in detail below with reference to embodiments and accompanying drawings, but the present invention is not limited thereto.

[0037] Example 1

[0038] (1) This embodiment provides a method for large-scale production of sulfide fast ion conductors and their application in all-solid-state lithium batteries; the chemical formula of the sulfide fast ion conductor is 0.55Li3PS4-0.45Li4SiS4, which is a tetragonal crystal system and P42 / nmc space group.

[0039] (2) Under the protection of argon gas at 60°C, Li2S, P2S5 and SiS2 were mixed in anhydrous acetonitrile at a molar ratio of 10.35:1.65:2.70 and mechanically stirred at 800 rpm for 100 hours to prepare a uniform emulsion.

[0040] (3) At 80°C, under an argon atmosphere, the mixed solution after the above reaction was mechanically stirred at 300 rpm to remove the solvent, and a slightly yellow homogeneous sulfide precursor was obtained.

[0041] (3) The solvent in the obtained sulfide precursor was further removed under vacuum conditions of 1 Pa and 120 °C.

[0042] (4) Place the sulfide precursor obtained in step 3 into a sealed container, place the container in a muffle furnace, and perform heating and sintering treatment in an argon atmosphere. Adjust the heating program to 5℃ / min, heat to 545℃, hold for 24h, and naturally cool to room temperature of 25℃ to obtain the sulfide fast ion conductor. Figure 1 Its corresponding XRD pattern;

[0043] (5) 300 mg of the obtained sulfide fast ion material powder was pressed into a thin sheet of about 2.5 mm under a pressure of 500 MPa. The sheet was then annealed and sintered again under argon protection in an argon atmosphere. The heating program was adjusted to 5 °C / min, the temperature was raised to 545 °C, held for 8 h, and then naturally cooled to room temperature to obtain an annealed sulfide fast ion conductor sheet. Carbon-coated aluminum foil was fixed on both sides of the sheet to form a sandwich structure. Its AC impedance spectrum was obtained by an electrochemical workstation. Figure 2 ), thereby calculating its ionic conductivity;

[0044] (6) The prepared sulfide fast ion conductor, NMC811 positive electrode active material powder and acetylene black are mixed evenly in a ratio of 30:70:0.5; after mixing evenly, 0.4 wt% polytetrafluoroethylene binder is added and shear force is applied to prepare a composite positive electrode sheet.

[0045] (7) The prepared sulfide fast ion conductor and polytetrafluoroethylene binder are mixed and ground in a ratio of 100:0.5 and shear force is applied to prepare an electrolyte film with a thickness of about 0.08 mm.

[0046] (8) A solid-state lithium battery was fabricated by stacking a Li-In alloy with a lithium metal mass fraction of 2 wt% as the negative electrode material with an electrolyte film and a composite positive electrode film. The cycle stability and rate performance of the solid-state lithium metal battery were verified by constant current charge-discharge cycle test and rate test.

[0047] Example 2

[0048] (1) This embodiment provides a method for large-scale production of sulfide fast ion conductors and their application in all-solid-state lithium batteries; the chemical formula of the sulfide fast ion conductor is 0.75Li3PS4-0.25Li4SiS4, which is an orthorhombic crystal system and Pnma space group.

[0049] (2) Under the protection of argon gas at 70°C, Li2S, P2S5 and SiS2 were mixed in anhydrous acetonitrile at a molar ratio of 3.25:0.75:0.5 and the mixture was stirred vigorously at 650 rpm for 72 hours to obtain a uniform emulsion.

[0050] (3) At 60°C, under an argon atmosphere, the mixed solution after the above reaction was mechanically stirred at 500 rpm to remove the solvent, and a slightly yellow homogeneous sulfide precursor was obtained.

[0051] (3) The solvent in the obtained sulfide precursor was further removed under vacuum conditions of 1 Pa and 120 °C.

[0052] (4) Place the sulfide precursor obtained in step 3 into a sealed container, place the container in a muffle furnace, and perform heating and sintering treatment in an argon atmosphere. Adjust the heating program to 10℃ / min, heat to 600℃, hold for 48h, and cool naturally to room temperature to obtain the sulfide fast ion conductor.

[0053] Figure 3 Its corresponding XRD pattern;

[0054] (5) 150 mg of the obtained sulfide fast ion material powder was pressed into a thin sheet of about 1.15 mm under a pressure of 500 MPa. Carbon-coated aluminum foil was fixed on both sides of the thin sheet to form a sandwich structure. Its AC impedance spectrum was obtained by an electrochemical workstation. Figure 4 ), thereby calculating its cold-pressed ionic conductivity.

[0055] (6) The prepared sulfide fast ion conductor, NMC811 positive electrode active material powder and acetylene black are mixed evenly in a ratio of 30:70:0.5; after mixing evenly, 0.4 wt% polytetrafluoroethylene binder is added and shear force is applied to prepare a composite positive electrode sheet.

[0056] (7) The prepared series of sulfide fast ion conductors and polytetrafluoroethylene binder were mixed and ground in a ratio of 100:0.5 and shear force was applied to prepare an electrolyte film with a thickness of about 0.08 mm.

[0057] (8) A solid-state lithium battery was fabricated by stacking a Li-In alloy with a lithium metal mass fraction of 2 wt% as the negative electrode material with an electrolyte film and a composite positive electrode film. The cycle stability and rate performance of the solid-state lithium metal battery were verified by constant current charge-discharge cycle test and rate test.

[0058] Example 3

[0059] (1) This embodiment provides a method for large-scale production of sulfide fast ion conductors and their application in all-solid-state lithium batteries; the chemical formula of the sulfide fast ion conductor is 0.67Li3PS4-0.33Li4SiS4, which is a mixture of orthorhombic and tetragonal crystal systems.

[0060] (2) Under the protection of argon gas at 65°C, Li2S, P2S5 and SiS2 were mixed in anhydrous acetonitrile at a molar ratio of 5:1:1 and the mixture was mechanically stirred vigorously at 800 rpm for 96 hours to prepare a uniform emulsion.

[0061] (3) At 100°C, under an argon atmosphere, the mixed solution after the above reaction was mechanically stirred at 200 rpm to remove the solvent, and a slightly yellow homogeneous sulfide precursor was obtained.

[0062] (3) The solvent in the obtained sulfide precursor was further removed under vacuum conditions of 1 Pa and 120 °C.

[0063] (4) Place the sulfide precursor obtained in step 3 into a sealed container, place the container in a muffle furnace, and perform heating and sintering treatment in an argon atmosphere. Adjust the heating program to 8℃ / min, heat to 550℃, hold for 60h, and cool naturally to room temperature to obtain the sulfide fast ion conductor. Figure 5 Its corresponding XRD pattern;

[0064] (5) 150 mg of the obtained sulfide fast ion material powder was pressed into a thin sheet of approximately 1.08 mm under a pressure of 500 MPa. Carbon-coated aluminum foil was fixed on both sides of the thin sheet to form a sandwich structure. Its AC impedance spectrum was obtained using an electrochemical workstation. Figure 6 ), thereby calculating its cold-pressed ionic conductivity.

[0065] (6) The prepared sulfide fast ion conductor, NMC811 positive electrode active material powder and acetylene black are mixed evenly in a ratio of 30:70:0.5; after mixing evenly, 0.4 wt% polytetrafluoroethylene binder is added and shear force is applied to prepare a composite positive electrode sheet.

[0066] (7) The prepared series of sulfide fast ion conductors and polytetrafluoroethylene binder were mixed and ground in a ratio of 100:0.5 and shear force was applied to prepare an electrolyte film with a thickness of about 0.08 mm.

[0067] (8) A solid-state lithium battery was fabricated by stacking a Li-In alloy with a lithium metal mass fraction of 2 wt% as the negative electrode material with an electrolyte film and a composite positive electrode film. The cycle stability and rate performance of the solid-state lithium metal battery were verified by constant current charge-discharge cycle test and rate test.

[0068] Comparative Example 1

[0069] Using high-energy mechanical ball milling, a pre-reaction process of ball milling at 500 rpm for 30 hours was used to replace the liquid-phase mixing pre-reaction, drying, and vacuum drying processes in Example 1 to obtain a sulfide precursor with the same composition as in Example 1. The rest of the process was the same as in Example 1.

[0070] Comparative Example 2

[0071] The sulfide precursor with the same composition as in Example 2 was obtained by ball milling at 500 rpm for 30 hours at a high-energy mechanical ball milling speed, replacing the liquid phase mixing pre-reaction, drying and vacuum drying processes in Example 2. The rest was the same as in Example 2.

[0072] Comparative Example 3

[0073] The sulfide precursor with the same composition as in Example 2 was obtained by ball milling at 500 rpm for 30 hours at a high-energy mechanical ball milling speed, replacing the liquid phase mixing pre-reaction, drying and vacuum drying processes in Example 3. The rest was the same as in Example 3.

[0074] Performance testing

[0075] 1. X-ray diffraction analysis

[0076] X-ray diffraction analysis was performed on the series of sulfide fast ion conductors prepared in Examples 1-3, and their corresponding XRD patterns are shown below. Figure 1 , Figure 3 and Figure 5 As shown.

[0077] Depend on Figure 1 It is known that the sulfide fast ion conductor prepared in Example 1 is a tetragonal crystal system with space group P42 / nmc. It has peaks at least at positions 2θ = 12.46°±0.50°, 14.18°±0.50°, 20.3±0.50°, 27.1°±0.50°, and 29.76°±0.50°.

[0078] Depend on Figure 3 It is known that the sulfide fast ion conductor prepared in Example 2 belongs to the orthorhombic crystal system and the Pnma space group. It has peaks at least at the positions of 2θ = 13.32°±0.50°, 17.38°±0.50°, 18.28±0.50°, 26.8°±0.50°, 29.94°±0.50°, and 30.60°±0.50°.

[0079] Depend on Figure 5It is known that the sulfide fast ion conductor prepared in Example 3 is a mixture of tetragonal and orthorhombic crystal systems. It has peaks at least at the following positions: 2θ = 12.46°±0.50°, 13.32°±0.50°, 14.18°±0.50°, 17.38°±0.50°, 18.28±0.50°, 20.3±0.50°, 26.8°±0.50°, 27.1°±0.50°, 29.76°±0.50°, and 30.60°±0.50°.

[0080] 2. Electrochemical impedance analysis

[0081] Electrochemical impedance spectroscopy was performed on the series of sulfide fast ion conductors prepared in Examples 1-3, and their electrochemical impedance spectra are shown below. Figure 2 , Figure 4 , Figure 6 As shown.

[0082] Depend on Figure 2 It can be seen that the impedance of the ion-blocking battery of the sulfide fast ion conductor prepared in Example 1 is 62Ω. According to the formula σ=L / RS, the ionic conductivity of the ion conductor can be calculated to be 2.01mS / cm.

[0083] Depend on Figure 4 It can be seen that the impedance of the ion-blocking battery of the sulfide fast ion conductor prepared in Example 2 is 113Ω. According to the formula σ=L / RS, the ionic conductivity of the ion conductor can be calculated to be 1.29mS / cm.

[0084] Depend on Figure 6 It can be seen that the impedance of the ion-blocking battery of the sulfide fast ion conductor prepared in Example 3 is 36Ω. According to the formula σ=L / RS, the ionic conductivity of the ion conductor can be calculated to be 3.82mS / cm.

[0085] Table 1 shows the statistical analysis of the ionic conductivity of the sulfide fast ion conductors prepared in the examples and comparative examples. It can be seen that there is no significant difference in the ionic conductivity of the sulfide fast ion conductors prepared in batches using the method described in this invention compared to those obtained by the mechanical ball milling-sintering method.

[0086] Table 1. Statistics on the ionic conductivity of the sulfide fast ion conductors prepared in the examples and comparative examples.

[0087]

[0088] Performance testing:

[0089] 1) Charge and discharge test:

[0090] The all-solid-state lithium batteries prepared in Examples 1-3 and Comparative Examples 1-3 were subjected to constant current charge-discharge tests. The test conditions were a charge-discharge voltage range of 2.5-4.2V, a charge-discharge rate of 0.2C, and a test temperature of 30℃. The capacity retention rate after 50 cycles is shown in Table 2.

[0091] Table 2. Capacity retention of all-solid-state lithium batteries prepared in Examples 1-3 and Comparative Examples 1-3

[0092] name Capacity retention Example 1 87％ Example 2 83％ Example 3 94％ Comparative Example 1 89％ Comparative Example 2 85％ Comparative Example 3 92％

[0093] Table 2 shows that the all-solid-state lithium batteries assembled using the sulfide solid electrolyte materials prepared in Examples 1-3 retained 83-94% of their capacity after 50 charge-discharge cycles. This is almost identical to the capacity retention of the all-solid-state lithium batteries in Comparative Examples 1-3 synthesized using the mechanical ball milling method after 50 charge-discharge cycles. This indicates that the sulfide fast ion conductor material prepared in this invention not only has similar ionic conductivity to the fast ion conductor synthesized by the mechanical ball milling-sintering method, but also similar electrochemical stability. This demonstrates that the large-scale preparation method of the sulfide fast ion conductor described in this invention can achieve the mass production of sulfide fast ion conductors with high ionic conductivity and excellent electrochemical performance. The all-solid-state lithium batteries assembled using the fast ion conductor synthesized in this invention exhibit excellent cycle stability.

[0094] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for batch preparation of a series of sulfide fast ion conductors, characterized in that, Includes the following steps: Step 1: Under conditions of 10–100℃, Li₂S, P₂S₅, and SiS₂ are mixed and stirred in an organic solvent for 72–168 hours to prepare a homogeneous emulsion. Step 2: At 50-120℃, the homogeneous emulsion is stirred to remove the solvent, thereby obtaining a homogeneous sulfide precursor. Step 3: Under vacuum conditions of 10–1 Pa and at 100–140 °C, the solvent in the obtained homogeneous sulfide precursor is further removed to obtain the precursor; Step 4: The precursor obtained in Step 3 is subjected to heating and sintering treatment in an inert gas atmosphere at 400-700℃ to obtain a series of sulfide fast ion conductors. The general formula of the series of sulfide fast ion conductors is xLi3PS4-(1-x)Li4SiS4, where 0.5≤x<1.

2. The method for batch preparation of a series of sulfide fast ion conductors according to claim 1, characterized in that, In step 1, the organic solvent is at least one of tetrahydrofuran, acetonitrile, malononitrile, and ethylene glycol dimethyl ether.

3. The method for batch preparation of a series of sulfide fast ion conductors according to claim 1, characterized in that, Steps 1 through 4 are all carried out under inert gas protection or dry conditions with a dew point below -20°C.

4. The method for batch preparation of a series of sulfide fast ion conductors according to claim 1, characterized in that, In step 4, the series of sulfide fast ion conductors have the following crystal configuration, and the crystal configuration structure has: An octahedron composed of Li and S elements; PS4 tetrahedron and SiS4 tetrahedron are formed by P and Si elements respectively with S element. Among them, the octahedron shares vertices or edges with the two types of tetrahedrons.

5. The method for batch preparation of a series of sulfide fast ion conductors according to claim 1, characterized in that, When 0.5≤x≤0.6, the prepared sulfide fast ion conductor is tetragonal and has space group P42 / nmc. The sulfide fast ion conductor exhibits peaks at least at 2θ = 12.46°±0.50°, 14.18°±0.50°, 20.3±0.50°, 27.1°±0.50° and 29.76°±0.50° in CuKα X-ray diffraction.

6. The method for batch preparation of a series of sulfide fast ion conductors according to claim 1, characterized in that, When 0.6 < x < 0.75, the prepared sulfide fast ion conductor is a two-phase mixture of tetragonal P42 / nmc space group and orthorhombic Pnma space group; The prepared sulfide fast ion conductor exhibits peaks in CuKa X-ray diffraction at at least the following positions: 2θ = 12.46°±0.50°, 13.32°±0.50°, 14.18°±0.50°, 17.38°±0.50°, 18.28±0.50°, 20.3±0.50°, 26.8°±0.50°, 27.1°±0.50°, 29.76°±0.50°, and 30.60°±0.50°.

7. The method for batch preparation of a series of sulfide fast ion conductors according to claim 1, characterized in that, When 0.75 ≤ x < 1, the prepared sulfide fast ion conductor is orthorhombic and belongs to the Pnma space group; The sulfide fast ion conductor exhibits peaks at least at 2θ = 13.32°±0.50°, 17.38°±0.50°, 18.28±0.50°, 26.8°±0.50°, 29.94°±0.50°, and 30.60°±0.50° in CuKα X-ray diffraction.

8. The application of the series of sulfide fast ion conductor materials prepared by the method according to any one of claims 1 to 7 in the preparation of all-solid-state lithium batteries.

9. The application according to claim 8, characterized in that, Specifically, it includes: The prepared series of sulfide fast ion conductors, positive electrode active material powder and acetylene black were mixed evenly in a mass ratio of 15-35:85-65:0-2; after being mixed evenly, polytetrafluoroethylene binder was added and shear force was applied to prepare a composite positive electrode film. A solid-state lithium battery was fabricated by stacking Li-In alloy as the negative electrode material with an electrolyte membrane and a composite positive electrode membrane.

10. The application according to claim 9, characterized in that, The preparation of the electrolyte membrane includes: The prepared series of sulfide fast ion conductors and polytetrafluoroethylene binder were mixed and ground in a mass ratio of 100:0.5 to 2 and shear force was applied to prepare an electrolyte membrane.

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