Submicron sulfide solid electrolyte and preparation method therefor

Abstract

A submicron sulfide solid electrolyte and a preparation method therefor. The preparation method comprises: weighing an appropriate amount of Li2S, P2S5, and LiX as starting materials, wherein X is a halogen element; mechanically milling the starting materials to obtain a sulfide solid electrolyte precursor; sintering the sulfide solid electrolyte precursor and cooling same at room temperature to obtain a large-particle-size sulfide solid electrolyte; and mechanically milling the large-particle-size sulfide solid electrolyte to obtain a submicron sulfide solid electrolyte. The submicron sulfide solid electrolyte is prepared by combining high-temperature solid-state sintering and mechanical milling, thereby effectively reducing starting material loss and improving starting material purity.

Description

Submicron-sized sulfide solid electrolyte and its preparation method Technical Field

[0001] This invention relates to the technical field of sulfide solid electrolytes, and specifically to a submicron-sized sulfide solid electrolyte and its preparation method. Background Technology

[0002] All-solid-state batteries have attracted much attention due to their high safety and higher energy density. Solid-state electrolytes, as key materials in all-solid-state batteries, directly affect the cycle performance of these batteries through their ionic conductivity, interfacial contact, and electrochemical stability. Sulfide solid-state electrolytes, with their excellent ionic conductivity and good interfacial contact, have become a research hotspot among inorganic solid-state electrolytes.

[0003] Currently, the main methods for preparing sulfide solid electrolytes are dry ball milling and wet ball milling. Dry ball milling produces sulfide solid electrolyte particles with larger sizes, requiring further processing. Wet ball milling produces smaller particles, but suffers from decreased ionic conductivity and poorer performance. Doping with halogen elements can improve the electrochemical stability of the electrolyte, enhance its stability in contact with the positive and negative electrodes, and improve the safety and stability of all-solid-state batteries. Currently, the amount of sulfide electrolytes prepared in the laboratory is small, thus affecting large-scale production. Therefore, developing new processes for the mass production of sulfide solid electrolytes is one of the challenges. Summary of the Invention

[0004] The purpose of this invention is to propose a submicron-scale sulfide solid electrolyte and its preparation method, which can improve the safety and stability of batteries, increase the mass production capacity of submicron-scale sulfide electrolytes, and provide assistance for the industrialization of all-solid-state batteries.

[0005] The present invention is implemented as follows: a submicron-sized sulfide solid electrolyte, which uses the chemical formula Li a P b S c X d The expression indicates that a, b, c, and d represent the number of Li, P, S, and X elements, respectively, under the condition of one submicron-sized sulfide solid electrolyte. a, b, c, and d ensure that the submicron-sized sulfide solid electrolyte is electrically neutral, where X is a halogen element, and the particle size of the submicron-sized sulfide solid electrolyte is between 100 nm and 1 μm.

[0006] For example, the halogen element is one or more of F, Cl, Br, and I.

[0007] For example, a + 5b = 2c + d.

[0008] For example, a = 5 to 6, b = 1, c = 4 to 5, d = 1 to 2.

[0009] For example, a = 5.5, b = 1, c = 4.5, d = 1.5; a = 6, b = 1, c = 5, d = 1; or a = 5.7, b = 1, c = 4.7, d = 1.3.

[0010] The present invention is implemented as follows: a method for preparing a submicron-sized sulfide solid electrolyte, comprising: weighing appropriate amounts of Li2S, P2S5, and LiX as raw materials, wherein X is a halogen element; mechanically grinding the raw materials to obtain a sulfide solid electrolyte precursor; sintering the sulfide solid electrolyte precursor and cooling it at room temperature to obtain a large-particle-size sulfide solid electrolyte; and mechanically grinding the large-particle-size sulfide solid electrolyte to obtain a submicron-sized sulfide solid electrolyte.

[0011] For example, the halogen element is one or more of F, Cl, Br, and I.

[0012] For example, the raw material further includes metal salts, which include one or more of Fe, Zn, Ge, Zr, Ca, Mg, Ti, and Ag.

[0013] For example, the mechanical grinding of the raw material is carried out in a high-speed mixer, a planetary ball mill, a horizontal ball mill, or an air jet mill.

[0014] For example, when mechanically grinding the raw material, the pressure inside the ball mill is 800 Pa to 1000 Pa, the ball-to-material ratio is (20 to 60): 1, the ball mill speed is 10 r / min to 50 r / min, and the ball milling time is 2 h to 4 h.

[0015] For example, the sintering temperature is 400°C to 500°C, and the sintering time is 2 hours to 4 hours.

[0016] For example, when mechanically grinding the large-particle-size sulfide solid electrolyte, the ball-to-material ratio is (20 to 60):1, the liquid-to-material ratio is 1:(20 to 60), the ball milling speed is 100 r / min to 2800 r / min, and the ball milling time is 0.5 h to 4 h.

[0017] For example, the large-particle-size sulfide solid electrolyte is mechanically milled in a ball milling solvent, which includes one or more of cyclohexane, xylene, o-xylene, methyl xylene, n-heptane, dimethyl carbonate, and isobutyl isobutyrate.

[0018] For example, the raw material is mechanically ground using dry ball milling, and the large-particle-size sulfide solid electrolyte is mechanically ground using wet ball milling.

[0019] For example, the molar ratio between Li2S, P2S5 and LiX is (2 to 6): 1: (2 to 4).

[0020] Based on the above solutions, this invention proposes a sulfide solid electrolyte and its preparation method, taking into account the properties of sulfide electrolytes. The preparation method combines high-temperature solid-state sintering and mechanical grinding to prepare submicron-sized sulfide solid electrolytes, thereby effectively reducing raw material loss and improving raw material purity. Compared with existing technologies, the technical solution of this invention brings at least one or more of the following beneficial effects:

[0021] (1) High-temperature solid-state sintering and mechanical grinding can be used to obtain high-purity submicron-level sulfide solid electrolytes that are stable at room temperature, with an ionic conductivity of 1.0 x 10⁻⁶ at room temperature. -3 S / cm up to 1.0x10 -2 S / cm.

[0022] (2) Mechanical grinding can effectively reduce the particle size of sulfide solid electrolytes. Applying it to composite cathodes can improve solid-solid contact in solid batteries, thereby improving the electrochemical performance of solid batteries.

[0023] (3) Optimize the ball milling process, control the rotation speed, ball-to-material ratio and time, so that the sulfide electrolyte is a pure phase after sintering, thereby improving the safety and stability of the battery made from it.

[0024] (4) The technical means of this invention can expand production and realize Li 5.5 PS 4.5 Cl 1.5 The large-scale production of sulfide solid electrolytes can achieve a daily output of 10 kg of submicron-sized sulfide solid electrolytes. Attached Figure Description

[0025] Figure 1 shows a scanning electron microscope (SEM) image of a large-particle-size sulfide solid electrolyte.

[0026] Figure 2 shows a scanning electron microscope (SEM) image of a submicron-sized sulfide solid electrolyte;

[0027] Figure 3 shows the X-ray diffraction (XRD) analysis results of submicron-scale sulfide solid electrolytes;

[0028] Figure 4 shows the long-cycle charge-discharge test results of the submicron-sized sulfide solid electrolyte of Example 1 and the large-particle-size sulfide solid electrolyte of Comparative Example 1. Detailed Implementation

[0029] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0030] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0031] The first embodiment of the present invention provides a submicron-sized sulfide solid electrolyte. The term "submicron-sized" refers to the particle size of the solid electrolyte being in the range of 100 nm to 1 μm, preferably 100 nm, 150 nm, 200 nm, 250 nm, 300 nm, 350 nm, 400 nm, 450 nm, 500 nm, 550 nm, 600 nm, 650 nm, 700 nm, 750 nm, 800 nm, 850 nm, 900 nm, 950 nm, or 1 μm.

[0032] Submicron-sized sulfide solid electrolyte with chemical formula Li a P b S c X d Let a, b, c, and d represent the number of Li, P, S, and X elements, respectively, under the condition of one submicron-sized sulfide solid electrolyte. a, b, c, and d ensure the submicron-sized sulfide solid electrolyte is electroneutrally neutral, and X is a halogen element. The halogen element may include, but is not limited to, one or more of F, Cl, Br, and I, preferably F, Cl, or Br. Under the condition of electroneutrality, a, b, c, and d can satisfy the following relationship: a + 5b = 2c + d. More preferably, a = 5 to 6, b = 1, c = 4 to 5, and d = 1 to 2. More preferably, a = 5, 5.1, 5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, or 6, b = 1, and c = 4, 4.1, 4.2, 4.3, or 4.4. 4.5, 4.6, 4.7, 4.8, 4.9, or 5, d = 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, or 2, preferably a = 5.5, b = 1, c = 4.5, d = 1.5; a = 6, b = 1, c = 5, d = 1; or a = 5.7, b = 1, c = 4.7, d = 1.3.

[0033] The second embodiment of the present invention provides a method for preparing a submicron-sized sulfide solid electrolyte. "Submicron-sized" refers to the particle size of the solid electrolyte being in the range of 100 nm to 1 μm, preferably 100 nm, 150 nm, 200 nm, 250 nm, 300 nm, 350 nm, 400 nm, 450 nm, 500 nm, 550 nm, 600 nm, 650 nm, 700 nm, 750 nm, 800 nm, 850 nm, 900 nm, 950 nm, or 1 μm. Detailed steps of the preparation method of this embodiment are described in the following paragraphs.

[0034] First, appropriate amounts of Li₂S, P₂S₅, and LiX are weighed out as raw materials, where X is a halogen element. The halogen element may include, but is not limited to, one or more of F, Cl, Br, and I, preferably F, Cl, or Br. The amounts of Li₂S, P₂S₅, and LiX weighed out can be expressed by mass or moles, calculated based on the ratio of the number of different elements in the chemical formula of the resulting submicron-sized sulfide solid electrolyte. Specifically, the submicron-sized sulfide solid electrolyte can be of the chemical formula Li₂S, P₂S₅, or LiX. a P b S c X d The definitions of a, b, c, and d are provided in the first embodiment and will not be detailed here. Based on this, the ratios between twice the number of Li₂S moles plus once the number of Liₓ moles, twice the number of P₂S₅ moles, once the number of Li₂S moles plus five times the number of P₂S₅ moles, and once the number of Liₓ moles satisfy a:b:c:d. Further calculation yields the molar ratio of Li₂S, P₂S₅, and Liₓ as (ad) / 2:b / 2:d. The molar ratio between Li2S, P2S5, and LiX can be, but is not limited to, (3 to 5): 1: (2 to 4), preferably (3, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, or 5): 1: (2, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3 to 4), and more preferably 4: 1: 3, 5: 1: 2, or 4.4: 1: 2.6.

[0035] To adjust the performance of submicron-sized sulfide solid electrolytes to meet practical requirements, raw materials may include, but are not limited to, metal salts, including one or more of Fe, Zn, Ge, Zr, Ca, Mg, Ti, and Ag. Under these conditions, submicron-sized sulfide solid electrolytes with the chemical formula Li... a-e P b S c M e Xd Let a, b, c, d, and e represent the number of Li, P, S, X, and M elements (metal elements in metal salts) under the condition of one submicron-sized sulfide solid electrolyte, respectively, and a, b, c, d, and e ensure that the submicron-sized sulfide solid electrolyte is electroneutrally neutral. Based on this, the ratio between the sum of 2 times the number of Li₂S moles plus 1 times the number of LiX moles, 2 times the number of P₂S₅ moles, the sum of 1 times the number of Li₂S moles plus 5 times the number of P₂S₅ moles, the number of LiX moles, and N times the number of metal salts satisfies (ae):b:c:d:e, where N is the number of metal elements under the condition of one metal salt. Further conversion yields the molar ratio between Li₂S, P₂S₅, LiX, and the metal salt as (ade) / 2:b / 2:d:e / N.

[0036] Next, the raw materials are mechanically ground to obtain a sulfide solid electrolyte precursor. The mechanical grinding of the raw materials can be carried out using, but is not limited to, dry ball milling; and the mechanical grinding of the raw materials can be carried out in, but is not limited to, a high-speed mixer, a planetary ball mill, a horizontal ball mill, or an air jet mill. When mechanically grinding raw materials, the pressure inside the ball mill jar can be, but is not limited to, 800 Pa to 1000 Pa, preferably 800 Pa, 810 Pa, 820 Pa, 830 Pa, 840 Pa, 850 Pa, 860 Pa, 870 Pa, 880 Pa, 890 Pa, 900 Pa, 910 Pa, 920 Pa, 930 Pa, 940 Pa, 950 Pa, 960 Pa, 970 Pa, 980 Pa, 990 Pa, or 1000 Pa; the ball-to-material ratio can be, but is not limited to (20 to 60):1, preferably 20:1, 25:1, 30:1, 35:1, 40:1, 45:1, 50:1, or 55:1. Or 60:1; the ball milling speed can be, but is not limited to, 10 r / min to 50 r / min, preferably 10 r / min, 15 r / min, 20 r / min, 25 r / min, 30 r / min, 35 r / min, 40 r / min, 45 r / min, or 50 r / min; the ball milling time can be, but is not limited to, 2 h to 4 h, preferably 2 h, 2 h and 10 min, 2 h and 20 min, 2 h and 30 min, 2 h and 40 min, 2 h and 50 min, 3 h, 3 h and 10 min, 3 h and 20 min, 3 h and 30 min, 3 h and 40 min, 3 h and 50 min, or 4 h.

[0037] The sulfide solid electrolyte precursor is then sintered and cooled to room temperature to obtain a large-particle-size sulfide solid electrolyte. The sintering temperature can be, but is not limited to, 400°C to 500°C, preferably 400°C, 410°C, 420°C, 430°C, 440°C, 450°C, 460°C, 470°C, 480°C, 490°C, or 500°C; the sintering time can be, but is not limited to, 2 hours to 4 hours, preferably 2 hours, 2 hours and 10 minutes, 2 hours and 20 minutes, 2 hours and 30 minutes, 2 hours and 40 minutes, 2 hours and 50 minutes, 3 hours, 3 hours and 10 minutes, 3 hours and 20 minutes, 3 hours and 30 minutes, 3 hours and 40 minutes, 3 hours and 50 minutes, or 4 hours. Furthermore, the particle size of the large-particle-size sulfide solid electrolyte can be, but is not limited to, 10 μm to 50 μm, preferably 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, or 50 μm, and more preferably 10 μm or 15 μm.

[0038] Finally, the large-particle-size sulfide solid electrolyte is mechanically ground to obtain submicron-sized sulfide solid electrolyte. Mechanical grinding of the large-particle-size sulfide solid electrolyte can be performed using, but is not limited to, wet ball milling; the mechanical grinding of the large-particle-size sulfide solid electrolyte can be carried out in, but is not limited to, a ball milling solvent, which may include, but is not limited to, one or more of cyclohexane, xylene, o-xylene, meso-xylene, n-heptane, dimethyl carbonate, and isobutyl isobutyrate. When mechanically grinding large-particle-size sulfide solid electrolytes, the ball-to-material ratio can be, but is not limited to, (20 to 60):1, preferably 20:1, 25:1, 30:1, 35:1, 40:1, 45:1, 50:1, 55:1, or 60:1; the liquid-to-material ratio can be, but is not limited to, 1:(20 to 60), preferably 1:20, 1:25, 1:30, 1:35, 1:40, 1:45, 1:50, 1:55, or 1:60; the ball milling speed can be, but is not limited to, 100 r / min to 2800 r / min, preferably 100 r / min, 200 r / min, 300 r / min, 400 r / min, 500 r / min, 600 r / min, 700 r / min, or 800 r / min. The ball milling speeds are 900 r / min, 1000 r / min, 1100 r / min, 1200 r / min, 1300 r / min, 1400 r / min, 1500 r / min, 1600 r / min, 1700 r / min, 1800 r / min, 1900 r / min, 2000 r / min, 2100 r / min, 2200 r / min, 2300 r / min, 2400 r / min, 2500 r / min, 2600 r / min, 2700 r / min, or 2800 r / min; the ball milling time can be, but is not limited to, 0.5 h to 4 h, preferably 0.5 h, 1 h, 1.5 h, 2 h, 2.5 h, 3 h, 3.5 h, or 4 h.

[0039] The invention is illustrated by way of example using the following embodiments:

[0040] Example 1:

[0041] Appropriate amounts of Li₂S, P₂S₅, and LiCl raw materials were weighed in a molar ratio of 4:1:3 and placed in a sealed ball mill jar with a ball-to-material ratio of 30:1. Preliminary ball milling was performed using mechanical ball milling at a speed of 50 r / min for 3 h. The ground sulfide solid electrolyte precursor was obtained by sieving and then sintered in a muffle furnace at 500℃ for 4 h. After cooling to room temperature, large-particle-size sulfide solid electrolytes were obtained (as shown in Figure 1). The obtained large-particle-size sulfide solid electrolytes were then placed in a mechanical mill at a speed of 2800 r / min for 0.5 h, with a material-to-liquid ratio of 1:30 and dimethyl carbonate as the solvent, to obtain submicron-sized sulfide solid electrolytes Li. 5.5 PS 4.5 Cl 1.5 (As shown in Figure 2), and its XRD analysis results are shown in Figure 3.

[0042] Submicron-sized sulfide solid electrolyte powder was fabricated into solid electrolyte sheets. The prepared Li 5.5 PS 4.5 Cl 1.5 The solid electrolyte has intact crystal grains without voids, and the particles are small, all below 1 μm.

[0043] Example 2:

[0044] Appropriate amounts of Li₂S, P₂S₅, and LiBr raw materials were weighed in a molar ratio of 4:1:3 and placed in a sealed ball mill jar with a ball-to-material ratio of 30:1. Preliminary ball milling was performed using mechanical ball milling at a speed of 30 r / min for 4 h. The ground sulfide solid electrolyte precursor was obtained by sieving and then sintered in a muffle furnace at 500℃ for 4 h. After cooling to room temperature, large-particle-size sulfide solid electrolyte was obtained. The obtained large-particle-size sulfide solid electrolyte was then placed in a mechanical mill at a speed of 2600 r / min for 0.7 h, with a material-to-liquid ratio of 1:30 and isobutyl isobutyrate as the solvent, to obtain submicron-sized sulfide solid electrolyte Li. 5.5 PS 4.5 Cl 1.5 .

[0045] Example 3:

[0046] Appropriate amounts of Li₂S, P₂S₅, and LiBr raw materials were weighed in a molar ratio of 4:1:3 and placed in a sealed ball mill jar with a ball-to-material ratio of 20:1. Preliminary ball milling was performed using mechanical ball milling at a speed of 40 r / min for 3 h. The ground sulfide solid electrolyte precursor was obtained by sieving and then sintered in a muffle furnace at 490℃ for 4 h. After cooling to room temperature, large-particle-size sulfide solid electrolyte was obtained. The obtained large-particle-size sulfide solid electrolyte was then placed in a mechanical mill at a speed of 2500 r / min for 0.6 h, with a material-to-liquid ratio of 1:25 and dimethyl carbonate as the solvent, to obtain submicron-sized sulfide solid electrolyte Li. 5.5 PS 4.5 Cl 1.5 .

[0047] Example 4:

[0048] Appropriate amounts of Li₂S, P₂S₅, and LiF raw materials were weighed in a molar ratio of 4:1:3 and placed in a sealed ball mill jar with a ball-to-material ratio of 20:1. Preliminary ball milling was performed using mechanical ball milling at a speed of 40 r / min for 3 h. The ground sulfide solid electrolyte precursor was obtained by sieving and then sintered in a muffle furnace at 490℃ for 4 h. After cooling to room temperature, large-particle-size sulfide solid electrolyte was obtained. The obtained large-particle-size sulfide solid electrolyte was then placed in a mechanical mill at a speed of 2600 r / min for 0.5 h, with a material-to-liquid ratio of 1:20 and dimethyl carbonate as the solvent, to obtain submicron-sized sulfide solid electrolyte Li. 5.5 PS 4.5 Cl 1.5 .

[0049] Example 5:

[0050] Appropriate amounts of Li₂S, P₂S₅, and LiCl raw materials were weighed in a molar ratio of 5:1:2 and placed in a sealed ball mill jar with a ball-to-material ratio of 20:1. Preliminary ball milling was performed using mechanical ball milling at a speed of 40 r / min for 3 h. The ground sulfide solid electrolyte precursor was obtained by sieving and then sintered in a muffle furnace at 500℃ for 6 h. After cooling to room temperature, large-particle-size sulfide solid electrolyte was obtained. The obtained large-particle-size sulfide solid electrolyte was then placed in a mechanical mill at a speed of 2800 r / min for 0.5 h with a material-to-liquid ratio of 1:20 and dimethyl carbonate as the solvent to obtain submicron-sized sulfide solid electrolyte Li₆PS₅Cl.

[0051] Example 6:

[0052] Appropriate amounts of Li₂S, P₂S₅, and LiCl raw materials were weighed at a molar ratio of 4.4:1:2.6 and placed in a sealed ball mill jar with a ball-to-material ratio of 20:1. Preliminary ball milling was performed using mechanical ball milling at a speed of 40 r / min for 3 h. The ground sulfide solid electrolyte precursor was obtained by sieving and then sintered in a muffle furnace at 480℃ for 5 h. After cooling to room temperature, large-particle-size sulfide solid electrolyte was obtained. The obtained large-particle-size sulfide solid electrolyte was then placed in a mechanical mill at a speed of 2200 r / min for 0.5 h, with a material-to-liquid ratio of 1:20 and dimethyl carbonate as the solvent, to obtain submicron-sized sulfide solid electrolyte Li. 5.7 PS 4.7 Cl 1.3 .

[0053] Comparative Example 1:

[0054] Appropriate amounts of Li₂S, P₂S₅, and LiCl raw materials were weighed in a molar ratio of 4:1:3. The raw materials were placed in a sealed ball mill jar with a ball-to-material ratio of 30:1. Preliminary ball milling was performed using mechanical ball milling at a speed of 50 r / min for 2 h. The ground sulfide solid electrolyte precursor was obtained by sieving and then sintered in a muffle furnace at 500℃ for 4 h. After cooling to room temperature, large-particle-size sulfide solid electrolyte was obtained. The large-particle sulfide solid electrolyte powder was then processed into solid electrolyte sheets.

[0055] As shown in Figure 4, the submicron-sized sulfide solid electrolyte of Example 1 retains 89.77% of its capacity after 500 cycles of 0.5C charge-discharge, compared to 80.35% for the large-particle sulfide solid electrolyte of Comparative Example 1. The submicron-sized sulfide solid electrolyte shows significant improvement in both its initial cycle performance and long-cycle performance.

[0056] The above content involving common knowledge will not be described in detail, as those skilled in the art will understand.

[0057] The above descriptions are merely some specific embodiments of the present invention and are not intended to limit the invention. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A submicron-scale sulfide solid electrolyte, characterized in that, With the chemical formula Li a P b S c X d The expression indicates that a, b, c, and d represent the number of Li, P, S, and X elements, respectively, under the condition of one submicron-sized sulfide solid electrolyte. a, b, c, and d ensure that the submicron-sized sulfide solid electrolyte is electrically neutral, where X is a halogen element, and the particle size of the submicron-sized sulfide solid electrolyte is between 100 nm and 1 μm.

2. The submicron-scale sulfide solid electrolyte according to claim 1, characterized in that, The halogen element is one or more of F, Cl, Br, and I.

3. The submicron-scale sulfide solid electrolyte according to claim 1, characterized in that, a + 5b = 2c + d.

4. The submicron-scale sulfide solid electrolyte according to claim 1, characterized in that, a = 5 to 6, b = 1, c = 4 to 5, d = 1 to 2.

5. The submicron-scale sulfide solid electrolyte according to claim 1, characterized in that, a=5.5, b=1, c=4.5, d=1.5; a=6, b=1, c=5, d=1; or a=5.7, b=1, c=4.7, d=1.

3.

6. A method for preparing a submicron-sized sulfide solid electrolyte, characterized in that, include: Weigh out appropriate amounts of Li2S, P2S5 and LiX as raw materials, wherein X is a halogen element; The raw material is mechanically ground to obtain a sulfide solid electrolyte precursor; The sulfide solid electrolyte precursor was sintered and cooled at room temperature to obtain a large-particle-size sulfide solid electrolyte. as well as The large-particle-size sulfide solid electrolyte is mechanically ground to obtain a submicron-sized sulfide solid electrolyte.

7. The method for preparing submicron-scale sulfide solid electrolyte according to claim 6, characterized in that, The halogen element is one or more of F, Cl, Br, and I.

8. The method for preparing submicron-scale sulfide solid electrolyte according to claim 6, characterized in that, The raw materials further include metal salts, which include one or more of Fe, Zn, Ge, Zr, Ca, Mg, Ti, and Ag.

9. The method for preparing submicron-scale sulfide solid electrolyte according to claim 6, characterized in that, The mechanical grinding of the raw materials is carried out in a high-speed mixer, a planetary ball mill, a horizontal ball mill, or an air jet mill.

10. The method for preparing submicron-scale sulfide solid electrolyte according to claim 6, characterized in that, When mechanically grinding the raw material, the pressure inside the ball mill is 800 Pa to 1000 Pa, the ball-to-material ratio is (20 to 60): 1, the ball mill speed is 10 r / min to 50 r / min, and the ball milling time is 2 h to 4 h.

11. The method for preparing submicron-scale sulfide solid electrolyte according to claim 6, characterized in that, The sintering temperature is 400℃ to 500℃, and the sintering time is 2h to 4h.

12. The method for preparing submicron-scale sulfide solid electrolyte according to claim 6, characterized in that, When mechanically grinding the large-particle-size sulfide solid electrolyte, the ball-to-material ratio is (20 to 60):1, the liquid-to-material ratio is 1:(20 to 60), the ball milling speed is 100 r / min to 2800 r / min, and the ball milling time is 0.5 h to 4 h.

13. The method for preparing submicron-sized sulfide solid electrolyte according to claim 6, characterized in that, The large-particle-size sulfide solid electrolyte is mechanically ground in a ball milling solvent, which includes one or more of cyclohexane, xylene, o-xylene, methyl xylene, n-heptane, dimethyl carbonate, and isobutyl isobutyrate.

14. The method for preparing submicron-scale sulfide solid electrolyte according to claim 6, characterized in that, The raw materials are mechanically ground using dry ball milling, while the large-particle-size sulfide solid electrolyte is mechanically ground using wet ball milling.

15. The method for preparing submicron-scale sulfide solid electrolyte according to claim 6, characterized in that, The molar ratio of Li2S, P2S5 and LiX is (2 to 6): 1: (2 to 4).

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