Nano-sized sulfide solid electrolyte material and method for preparing the same

Abstract

The present invention provides a method for preparing a nano-sized sulfide solid electrolyte material, which includes the steps of: 1) preparing a lithium sulfide material; 2) mixing 10-100 parts by weight of a solvent, 0-1 parts by weight of a dispersant, and 1 part by weight of a raw material containing a lithium sulfide material in a sealed container and drying the mixture to obtain an electrolyte precursor powder; and 3) heat-treating and pulverizing the electrolyte precursor powder obtained in step 2) to obtain a nano-sized sulfide solid electrolyte material. The preparation process of the present invention is simple, and the size of the prepared electrolyte can reach the nanometer level.

Description

Technical Field

[0001] The present invention belongs to the technical field of batteries, and relates to a nano-sized sulfide solid electrolyte material and a preparation method thereof.

Background Art

[0002] Lithium-ion batteries are widely used in many fields including portable electronic products, electric vehicles, grid storage, etc. However, for future electric vehicles with a long driving range, a higher energy density is required, while the energy density of commercially available lithium-ion batteries has already reached its limit. In addition, leakage of highly flammable liquid electrolytes and thermal instability cause serious safety problems for commercially available lithium-ion batteries. To solve these problems, all-solid-state lithium battery technology has been widely regarded as one of the most promising candidate technologies.

[0003] Inorganic solid electrolytes are leak-free, non-volatile, have a wide potential window and higher thermal stability, thus greatly improving the safety of lithium-ion batteries. Moreover, by successfully selecting a lithium negative electrode, the battery energy density can be greatly improved, and inorganic solid electrolytes are more suitable as high-voltage positive electrode materials than liquid electrolytes. Among inorganic solid electrolytes, sulfide solid electrolytes have high conductivity and good mechanical properties.

[0004] Currently, since the particle size of sulfide electrolytes is large (5 - 10 μm) and the specific surface area of electrolyte particles is small, in order to ensure sufficient contact between the active material and the electrolyte in the positive electrode layer and realize normal ion transport in the composite positive electrode material of all-solid-state lithium batteries, it is necessary to add electrolyte powder with a mass ratio of 30% or more. As a result, the content of the active material component in the positive electrode material is reduced.

Summary of the Invention

[0005] In view of the drawbacks in the prior art, the present invention provides a nano-sized sulfide solid electrolyte material and a method for preparing the same. The method achieves the purpose of refining the crystal grain structure and reducing the particle size by adding a plurality of solvents and dispersants.

[0006] One aspect of the present invention is a nano-sized sulfide solid electrolyte material, wherein the nano-sized sulfide solid electrolyte material has one or more of the chemical formulas shown in Formula I, Formula II, and Formula III. (100 - x - y)Li2S·xP2S5·yM m N n Formula I Here, 0 ≦ x < 100, 0 ≦ y < 100, 0 ≦ x + y < 100, 0 ≦ m < 4, 0 ≦ n < 6, M is one or more of Li, Ge, Si, Sn, and Sb, and N is one or more of Se, O, Cl, Br, and I. Li 10±l Ge 1-g G g P 2-q Q q S 12-w W w Formula II Here, 0 ≦ l < 1, 0 ≦ g ≦ 1, 0 ≦ q ≦ 2, 0 ≦ w < 1, G is Si and / or Sn, Q is Sb, and W is one or more of O, Se, Cl, Br, and I. Li 6±l P 1-e E e S 5±l-r R r X 1±l Formula III Here, 0 ≦ l < 1, 0 ≦ e < 1, 0 ≦ r < 1, E is one or more of Ge, Si, Sn, and Sb, R is O and / or Se, and X is one or more of Cl, Br, and I. Provided is a nano-sized sulfide solid electrolyte material, wherein the size of the nano-sized sulfide solid electrolyte material is 10 - 500 nm.

[0007] The sulfide solid electrolyte material provided by the present invention has a nano size, and the size is 10 to 500 nm. As a battery electrolyte, it can effectively improve the contact area with the active material of the positive electrode and the ion transport ability, and further improve the ratio of the active material in the composite positive electrode, which is advantageous for improving the battery performance.

[0008] Preferably, the size of the nano-sized sulfide solid electrolyte material is 10 to 100 nm.

[0009] Preferably, the nano-sized sulfide solid electrolyte material has a room temperature ionic conductivity of 1×10 -4 ~1×10 -1 S / cm. Room temperature in this specification refers to 15 to 35 °C.

[0010] Preferably, the nano-sized sulfide solid electrolyte material has a room temperature ionic conductivity of 1×10 -3 ~5×10 -2 S / cm.

[0011] Another aspect of the present invention is a method for preparing a nano-sized sulfide solid electrolyte material, comprising: Step 1) of preparing a lithium sulfide material; Step 2) of mixing 10 to 100 parts by weight of a solvent, 0 to 1 part by mass of a dispersant, and 1 part by weight of a raw material containing a lithium sulfide material in a sealed container and drying to obtain an electrolyte precursor powder; Step 3) of heat-treating the electrolyte precursor powder obtained in Step 2) and pulverizing it to obtain a nano-sized sulfide solid electrolyte material. A method for preparing a nano-sized sulfide solid electrolyte material is provided.

[0012] The present invention achieves the purpose of refining the crystal grain structure and reducing the particle size by adding a plurality of solvents or adding a plurality of both the solvent and the dispersant to increase the nucleation rate of the electrolyte crystals, while mechanically dispersing to crush the growing dendrites and increase the number of crystal nuclei.

[0013] Preferably, the method for preparing the lithium sulfide material includes one or more of a ball milling method, a carbon thermal reduction method, lithiation of a sulfur-containing chemical substance, sulfidation of lithium metal nanoparticles, and a reaction between a lithium-containing substance and a sulfur-containing substance.

[0014] Preferably, the solvent in step 2) is one or a combination of one or more of toluene, chlorobenzene, xylene, dimethyl carbonate, N-methylformamide, n-hexane, glyme, dibutyl ether, ethanol, 1,2-ethylenediamine, 1,2-ethanedithiol, acetonitrile, tetrahydrofuran, methanol, isopropyl ether, acetone, hexene, and ethyl acetate.

[0015] Preferably, the dispersant in step 2) is one or a combination of one or more of Triton X-100, sodium hexametaphosphate, sodium pyrophosphate, sodium tripolyphosphate, sodium dodecyl sulfate, ammonium lauryl sulfate, sodium lauryl ether sulfate, polyvinylpyrrolidone, Pluronic (registered trademark) F-127, Tween 80, and cetyltrimethylammonium bromide.

[0016] Preferably, in step 2), the part by mass of the dispersant satisfies 0 < part by mass of the dispersant ≤ 1. The present invention is advantageous for reducing the particle size by adding a plurality of both the solvent and the dispersant.

[0017] Preferably, the mixing method in step 2) includes one or a combination of one or more of mechanical stirring, mechanical shaking, ultrasonic dispersion, ball milling, and roll milling.

[0018] Preferably, the mixing time is 1 to 48 hours.

[0019] Preferably, the drying method is one or a combination of one or more of vacuum suction filtration, vacuum drying, and air drying.

[0020] Preferably, in step 2), the drying temperature is 10 to 100°C, and the drying time is 1 to 48 hours.

[0021] Preferably, in step 3), the heat treatment temperature is 100 to 600°C, and the heat treatment time is 0.5 to 24 hours.

[0022] Yet another aspect of the present invention provides a all-solid-state lithium battery including a positive electrode, a negative electrode, and the nano-sized sulfide solid electrolyte material.

[0023] Preferably, the mass percentage of the active material in the positive electrode is 70 to 99.9%. The active material is not limited, and its specific type is not limited. Any electrode active material well-known to those skilled in the art can be used in the present invention.

[0024] Compared with the prior art, the present invention has the following beneficial effects. 1. The sulfide solid electrolyte material of the present invention is nano-sized, and its size is 10 to 500 nm. 2. The nano-sized sulfide solid electrolyte material according to the present invention has high ionic conductivity. 3. By the preparation method provided by the present invention, a solvent that is 10 to 100 times the mass of the raw material is added, and combined with mechanical dispersion, the purpose of refining the crystal grain structure and reducing the particle size is achieved, thereby obtaining a nano-sized electrolyte material. 4. By the preparation method provided by the present invention, both a solvent and a dispersant are added, and by using the solvent and the dispersant together, the size of the material can be significantly reduced. 5. By using the nano-sized sulfide solid electrolyte material according to the present invention as the electrolyte of an all-solid-state lithium battery, the contact area and ion transport ability with the active material of the positive electrode can be effectively improved, and furthermore, the ratio of the active material in the composite positive electrode can be improved to 70 to 99.9%, which is advantageous for improving battery performance.

Brief Description of the Drawings

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Mode for Carrying Out the Invention

[0026] Hereinafter, the technical solutions of the present invention will be further described through specific examples and drawings. It should be understood that the specific examples described here are only used to assist in understanding the present invention and are not used to specifically limit the present invention. Unless otherwise specified, the raw materials used in the examples of the present invention are all raw materials commonly used in this field, and the methods used in the examples are all general methods in this field.

[0027] Example 1 The sulfide solid electrolyte material of this example has the chemical formula Li6PS5Cl and was obtained by the following preparation method. 1), A lithium-containing substance and a sulfur-containing substance were reacted with each other to prepare lithium sulfide. Specifically, metallic lithium and elemental sulfur were respectively dissolved in diethyl ether at a molar ratio of 2.1:1, mixed, and then reacted by vacuum distillation to obtain lithium sulfide. 2), Inside the glove box, 20 parts by weight of anhydrous acetonitrile and 1 part by weight of raw materials (the molar mass ratio of Li2S, P2S5 and LiCl is 5:1:2) were mixed, stirred and mixed at 300 r / min for 24 hours in a container, and then filtered by suction under reduced pressure at 80 °C until the solvent was clearly gone, transferred into a vacuum oven and dried under vacuum at 80 °C for 12 hours, and naturally cooled to room temperature to obtain a precursor powder of the electrolyte. 3), The obtained precursor powder of the electrolyte was heat-treated at 520 °C for 4 hours under the protection of an inert atmosphere (argon gas), naturally cooled to room temperature, and pulverized to obtain a nano-sized Li6PS5Cl sulfide solid electrolyte material.

[0028] The prepared nano-sized Li6PS5Cl sulfide solid electrolyte material has a particle size of 100 - 200 nm, and its scanning electron microscope image is shown in Figure 1. The prepared nano-sized Li6PS5Cl sulfide solid electrolyte material has an alternating current impedance spectrum diagram shown in Figure 2, and the room temperature ionic conductivity of the electrolyte is 2.3×10 -3 S / cm.

[0029] Using LiCoO2 as the active material of the positive electrode, with the mass ratio of LiCoO2 in the composite positive electrode material being 85%, using the above electrolyte as the electrolyte layer, and using metallic lithium as the negative electrode, an all-solid-state battery was assembled. The battery can be stably cycled 100 times at 1C, and the capacity retention rate is 90%. The cycle performance diagram of the battery is shown in Figure 3, and the charge-discharge curve diagram is shown in Figure 4.

[0030] Example 2 The sulfide solid electrolyte material of this example has a chemical formula of Li 5.4 PS 4.4 Cl 1.6 and was obtained by the following preparation method. 1), Lithium sulfide was prepared by sulfidation of lithium metal nanoparticles. Specifically, lithium metal nanoparticles were dispersed in a tetrahydrofuran - n - hexane medium, and a mixed gas of hydrogen sulfide gas and argon gas was passed through it and reacted for 24 hours to obtain lithium sulfide. 2), 10 parts by weight of a mixed solvent of ethanol and ethyl acetate (the volume ratio of ethanol to ethyl acetate is 4:6), and 1 part by weight of raw materials (the molar mass ratio of Li2S, P2S5 and LiCl is 3.8:1:3.2) were stirred and mixed in a container at 400 r / min for 24 hours, then filtered under reduced pressure at 80 °C, and then vacuum dried at 80 °C for 12 hours, and naturally cooled to room temperature to obtain a precursor powder of the electrolyte. 3), The treated precursor powder of the electrolyte was heat-treated at 500 °C for 4 hours under the protection of an inert atmosphere (argon gas), naturally cooled to room temperature, and pulverized to obtain nano-sized Li 5.4 PS 4.4 Cl 1.6 sulfide solid electrolyte.

[0031] The prepared nano-sized sulfide solid electrolyte has a particle size of about 50-100 nm, and its scanning electron microscope image is shown in Fig. 5. The alternating current impedance spectrum diagram of the prepared nano-sized sulfide solid electrolyte material is shown in Fig. 6. The room temperature ionic conductivity of the electrolyte was 3.2×10 -3 S / cm.

[0032] LiNi 0.8 Co 0.1 Mn 0.1 O2 was used as the active material of the positive electrode, and the mass ratio of LiNi 0.8 Co 0.1 Mn 0.1 O2 in the composite positive electrode material was 95%. Using the above electrolyte as the electrolyte layer and metallic lithium as the negative electrode, a all-solid-state battery was assembled. The battery could be stably cycled 170 times at 1C, and the capacity retention rate was 83%. The cycle performance diagram of the battery is shown in Fig. 7, and the charge-discharge curve diagram is shown in Fig. 8.

[0033] Example 3 The sulfide solid electrolyte material of this example has the chemical formula Li3PS4 and was obtained by the following preparation method. 1), Li2S was prepared by lithiating a sulfur-containing chemical substance. Specifically, elemental sulfur and anhydrous lithium hydroxide were heated in a hydrogen gas atmosphere to prepare lithium sulfide. 2), 25 parts by weight of tetrahydrofuran and 0.01 part by mass of Triton X-100 were mixed, and then 1 part by weight of raw material (molar ratio of Li2S to P2S5 is 3:1) was added. After shaking and mixing at 300 rpm for 24 hours in a mixing container, it was filtered under reduced pressure at 70 °C, then vacuum dried at 70 °C for 12 hours, and naturally cooled to room temperature to obtain a precursor powder of the electrolyte. 3), The treated precursor powder of the electrolyte was heat-treated at 250 °C for 4 hours under the protection of an inert atmosphere (argon gas), naturally cooled to room temperature, and pulverized to obtain a nano-sized Li3PS4 sulfide solid electrolyte.

[0034] The prepared nano-sized sulfide solid electrolyte had a particle size of about 50 nm, and the room temperature ionic conductivity of the electrolyte was 2.1×10 -4 S / cm.

[0035] Using LiCoO2 as the active material of the positive electrode, the mass ratio of LiCoO2 in the composite positive electrode material was 85%, using the above electrolyte as the electrolyte layer, and metallic lithium as the negative electrode, a all-solid-state battery was assembled. The battery was stably cyclable 100 times at 0.1C, and the capacity retention rate was 86.1%.

[0036] Example 4 The sulfide solid electrolyte material of this example had a chemical formula of Li7P3S 11 and was obtained by the following preparation method. 1), Li2S was prepared by the carbon thermal reduction method. Specifically, anhydrous lithium sulfate, glucose, and hard carbon were mixed at a mass ratio of 1:2:5, and heated to 900 °C in a hydrogen gas atmosphere for reaction to prepare lithium sulfide. 2), 50 parts by weight of toluene and 0.1 part by mass of sodium hexametaphosphate were mixed, and then 1 part by weight of raw material (molar mass ratio of Li2S and P2S5 is 7:3) was added. After shaking and mixing at 500 rpm for 24 hours in the container, it was filtered under reduced pressure at 100 °C until the solvent was clearly gone, transferred into a vacuum oven and vacuum dried at 100 °C for 12 hours, and naturally cooled to room temperature to obtain a precursor powder of the electrolyte. 3) The processed electrolyte precursor powder was heat-treated at 260 °C for 4 hours under the protection of an inert atmosphere (argon gas), naturally cooled to room temperature, and pulverized to obtain nano-sized Li7P3S 11 sulfide solid electrolyte.

[0037] The prepared nano-sized sulfide solid electrolyte had a particle size of about 60 nm, and the room-temperature ionic conductivity of the electrolyte was 1.2×10 -3 S / cm.

[0038] LiNi 0.6 Co 0.2 Mn 0.2 O2 was used as the active material of the positive electrode. The mass ratio of LiNi 0.6 Co 0.2 Mn 0.2 O2 in the composite positive electrode material was 88%. Using the above electrolyte as the electrolyte layer and metallic lithium as the negative electrode, a all-solid-state battery was assembled. The battery was stably cyclable 500 times at 1C, and the capacity retention rate was 90.3%.

[0039] Example 5 The sulfide solid electrolyte material of this example had a chemical formula of Li6PS5Cl and was obtained by the following preparation method. 1) Li2S was prepared by the ball milling method. Specifically, dry sulfur powder and lithium hydride powder were mixed at a molar ratio of 1:3 and placed in a ball mill pot, and ball milled at 400 r / min at room temperature for 24 hours to obtain lithium sulfide. 2) 30 parts by weight of a mixed solvent of tetrahydrofuran and ethanol (the volume ratio of tetrahydrofuran to ethanol was 2:1) and 0.01 part by weight of polyvinylpyrrolidone were mixed, and 1 part by weight of raw materials (the molar mass ratio of Li2S, P2S5 and LiCl was 5:1:2) was added. After ball milling and mixing at 500 r / min in a ball mill pot for 24 hours, vacuum drying was carried out at 70 °C for 24 hours, and then naturally cooled to room temperature to obtain electrolyte precursor powder. 3), The processed electrolyte precursor powder was heat-treated at 550 °C for 4 hours under the protection of an inert atmosphere (argon gas), naturally cooled to room temperature, and pulverized to obtain a nano-sized Li6PS5Cl sulfide solid electrolyte.

[0040] The prepared nano-sized sulfide solid electrolyte had a particle size of about 80 nm, and the room temperature ionic conductivity of the electrolyte was 3.1×10 -3 S / cm.

[0041] Using LiCoO2 as the cathode active material, with the mass ratio of LiCoO2 in the composite cathode material being 85%, the above electrolyte as the electrolyte layer, and metallic lithium as the anode, a all-solid-state battery was assembled. The battery was stably cyclable 100 times at 2C, and the capacity retention rate was 90.1%.

[0042] Example 6 The sulfide solid electrolyte material of this example was obtained by the following preparation method. 1), Li2S was prepared by the ball milling method. Specifically, dry sulfur powder and lithium hydride powder were mixed at a molar ratio of 1:2 and placed in a ball mill pot, and ball milled at 500 r / min at room temperature for 12 hours to obtain lithium sulfide. 2), 42 parts by weight of a mixed solvent of chlorobenzene and ethyl acetate (the volume ratio of chlorobenzene to ethyl acetate is 4:6) and 0.01 part by weight of Tween 80 were mixed, and then 1 part by weight of raw materials (the molar mass ratio of Li2S, P2S5 and GeS2 is 5:1:1) was added, and after ball milling and mixing at 300 r / min in the ball mill pot for 24 hours, vacuum dried at 80 °C for 24 hours, and naturally cooled to room temperature to obtain an electrolyte precursor powder. 3), The processed electrolyte precursor powder was heat-treated at 600 °C for 4 hours under the protection of an inert atmosphere (argon gas), naturally cooled to room temperature, and pulverized to obtain a nano-sized Li 10 GeP2S 12 and Li3PS4 composite sulfide solid electrolyte.

[0043] The prepared nano-sized sulfide solid electrolyte has a particle size of about 20 nm, and the room-temperature ionic conductivity of the electrolyte is 1.1×10 -2 S / cm.

[0044] LiNi 0.8 Co 0.15 Al 0.05 O2 was used as the active material of the positive electrode. With the mass ratio of LiNi 0.8 Co 0.15 Al 0.05 O2 in the composite positive electrode material being 99%, using the above electrolyte as the electrolyte layer, and metallic lithium as the negative electrode, a all-solid-state battery was assembled. The battery could be stably cycled 500 times at 2C, and the capacity retention rate was 94.1%.

[0045] Example 7 The sulfide solid electrolyte material of this example was obtained by the following preparation method. 1), Li2S was prepared by the ball milling method. Specifically, dry sulfur powder and lithium hydride powder were mixed at a molar ratio of 1:2.5 and put into a ball mill pot, and ball milled at 300 r / min at room temperature for 24 hours to obtain lithium sulfide. 2), 15 parts by weight of anhydrous acetonitrile and 0.01 part by mass of Triton X-100 were mixed, and then 1 part by weight of the raw material (the molar mass ratio of Li2S, P2S5 and GeS2 was 5:1:1) was added. After stirring and mixing in a container at 600 r / min for 24 hours, suction filtration was carried out under reduced pressure at 80°C, and then vacuum drying was carried out at 80°C for 12 hours, and natural cooling to room temperature was carried out to obtain the electrolyte precursor powder. 3), The treated electrolyte precursor powder was heat treated at 600°C for 4 hours under the protection of an inert atmosphere (argon gas), naturally cooled to room temperature, and pulverized to obtain a nano-sized composite sulfide solid electrolyte of Li 10 GeP2S 12 and Li3PS4.

[0046] The prepared nano-sized sulfide solid electrolyte has a particle size of about 70 nm, and the room-temperature ionic conductivity of the electrolyte is 1.2×10 -2 S / cm.

[0047] LiNi 0.5 Mn 1.5 Using LiNi 0.5 Mn 1.5 O4 as the cathode active material, with the mass ratio of LiNi

[0048] Example 8 The sulfide solid electrolyte material of this example has the chemical formula Li6PS5Br and was obtained by the following preparation method. 1), Using the ball milling method, a lithium-containing substance and a sulfur-containing substance were reacted with each other to prepare Li2S. Specifically, metallic lithium and elemental sulfur were respectively dissolved in tetrahydrofuran at a molar ratio of 2.2:1, mixed at 200 r / min for 24 hours by the ball milling method, and then subjected to vacuum distillation for reaction to obtain lithium sulfide. 2), Inside the glove box, 25 parts by weight of dimethyl carbonate and 0.01 part by mass of sodium tripolyphosphate were mixed. Then, 1 part by weight of the raw material (the molar mass ratio of Li2S, P2S5, and LiBr is 5:1:2) was added, and ultrasonic dispersion mixing was carried out in the container for more than 24 hours. Then, vacuum suction filtration was carried out at 80 °C, followed by vacuum drying at 90 °C for 12 hours, and natural cooling to room temperature to obtain the electrolyte precursor powder. 3), The treated electrolyte precursor powder was heat-treated at 550 °C for 4 hours under the protection of an inert atmosphere (argon gas), naturally cooled to room temperature, and pulverized to obtain a nanosized Li6PS5Br sulfide solid electrolyte.

[0049] The prepared nanosized sulfide solid electrolyte has a particle size of about 40 nm, and the room temperature ionic conductivity of the electrolyte is 7.2×10 -4 S / cm.

[0050] Using LiCoO₂ as the cathode active material, with the mass ratio of LiCoO₂ in the composite cathode material being 83%, using the above electrolyte as the electrolyte layer, and metallic lithium as the anode, a all-solid-state battery was assembled. The battery was stably cyclable 100 times at 0.1C, and the capacity retention rate was 92.6%.

[0051] Example 9 The sulfide solid electrolyte material of this example has the chemical formula Li 5.4 PS 4.4 Cl 1.2 Br 0.4 and was obtained by the following preparation method. 1), Li₂S was prepared by the ball milling method. Specifically, dry sulfur powder and lithium hydride powder were mixed at a molar ratio of 1:1 and placed in a ball mill pot, and ball milled at 100 r / min at room temperature for 24 hours to obtain lithium sulfide. 2), 64 parts by weight of a mixed solvent of tetrahydrofuran and ethanol (the volume ratio of tetrahydrofuran to ethanol is 2:1) and 0.01 part by weight of sodium lauryl ether sulfate were mixed, and then 1 part by weight of raw materials (the molar ratio of Li₂S, P₂S₅, LiCl and LiBr is 3.8:1:2.4:0.8) was added. After rolling and milling and mixing at 300 r / min in the container for 24 hours, vacuum suction filtration was carried out at 120 °C, and then vacuum drying was carried out at 120 °C for 12 hours, and natural cooling to room temperature was carried out to obtain electrolyte precursor powder. 3), The treated electrolyte precursor powder was heat treated at 550 °C for 4 hours under the protection of an inert atmosphere (argon gas), naturally cooled to room temperature, and pulverized to obtain nano-sized Li 5.4 PS 4.4 Cl 1.2 Br 0.4 sulfide solid electrolyte.

[0052] The prepared nano-sized sulfide solid electrolyte has a particle size of about 30 nm, and the room temperature ionic conductivity of the electrolyte is 6.8×10 -3 S / cm.

[0053] Using Co9S8 as the cathode active material, with the mass ratio of Co9S8 in the composite cathode material being 90%, using the above electrolyte as the electrolyte layer, and using metallic lithium as the anode, a all-solid-state battery was assembled. The battery was stably cyclable 100 times at 1C, and the capacity retention rate was 90.4%.

[0054] Example 10 The sulfide solid electrolyte material of this example has the chemical formula Li 5.4 PS 4.4 Cl 1.6 and was obtained by the following preparation method. 1), Prepare Li2S by the sulfidation method of metallic lithium nanoparticles. Disperse the metallic lithium nanoparticles in a tetrahydrofuran - n - hexane medium, and introduce a mixed gas of hydrogen sulfide gas and argon gas into it and react for 24 hours to obtain lithium sulfide. 2), Add 1 part by weight of raw material (the molar mass ratio of Li2S, P2S5 and LiCl is 3.8:1:3.2) to 75 parts by weight of acetonitrile, roll mill and mix at 400 r / min in the container for 24 hours, then perform vacuum suction filtration at 70 °C, and then perform vacuum drying at 70 °C for 12 hours, and naturally cool to room temperature to obtain the electrolyte precursor powder. 3), Under the protection of an inert atmosphere (argon gas), heat - treat the treated electrolyte precursor powder at 500 °C for 4 hours, naturally cool to room temperature, and pulverize to obtain a nano - sized Li 5.4 PS 4.4 Cl 1.6 sulfide solid electrolyte.

[0055] The prepared nano - sized sulfide solid electrolyte has a particle size of about 150 nm, and the room - temperature ionic conductivity of the electrolyte is 6.2×10 -3 S / cm.

[0056] Using LiCoO2 as the cathode active material, with the mass ratio of LiCoO2 in the composite cathode material being 80%, using the above electrolyte as the electrolyte layer, and using metallic lithium as the anode, a all - solid - state battery was assembled. The battery was stably cyclable 500 times at 0.5C, and the capacity retention rate was 90.3%.

[0057] Example 11 The sulfide solid electrolyte material of this example has a chemical formula of Li7P2S8I and was obtained by the following preparation method. 1), A lithium-containing substance and a sulfur-containing substance were reacted with each other to prepare Li2S. Specifically, metallic lithium and elemental sulfur were respectively dissolved in toluene at a molar ratio of 2.1:1, mixed, and then subjected to vacuum distillation for reaction to obtain lithium sulfide. 2), Inside a glove box, 90 parts by weight of acetone and 0.01 part by mass of Triton X-100 were mixed. Then, 1 part by weight of raw materials (the molar mass ratio of Li2S, P2S5, and LiI was 3:1:1) was added, and after stirring and mixing in the container for 24 hours, vacuum suction filtration was performed at 60 °C. Next, vacuum drying was carried out at 60 °C for 12 hours, and natural cooling to room temperature was carried out to obtain electrolyte precursor powder. 3), The treated electrolyte precursor powder was heat-treated at 200 °C for 4 hours under the protection of an inert atmosphere (argon gas), naturally cooled to room temperature, and pulverized to obtain a nano-sized Li7P2S8I sulfide solid electrolyte.

[0058] The prepared nano-sized sulfide solid electrolyte had a particle size of about 100 nm, and the room temperature ionic conductivity of the electrolyte was 1.4×10 -4 S / cm.

[0059] LiNi 0.6 Co 0.2 Mn 0.2 O2 was used as the active material of the positive electrode. The mass ratio of LiNi 0.6 Co 0.2 Mn 0.2 O2 in the composite positive electrode material was 75%. Using the above electrolyte as the electrolyte layer and metallic lithium as the negative electrode, an all-solid-state battery was assembled. The battery could be stably cycled 500 times at 0.1C, and the capacity retention rate was 90.3%.

[0060] Example 12 The sulfide solid electrolyte material of this example was obtained by the following preparation method. 1) Li₂S was prepared by the ball milling method. Specifically, dry sulfur powder and lithium hydride powder were mixed at a molar ratio of 1:2, placed in a ball mill pot, and ball milled at 500 r / min at room temperature for 12 hours to obtain lithium sulfide. 2) 55 parts by weight of hexene and 0.01 part by weight of cetyltrimethylammonium bromide were mixed, and then 1 part by weight of raw material (the molar mass ratio of Li₂S, P₂S₅ and GeS₂ was 5:1:1) was added. After shaking and mixing at 500 times / min for 24 hours in a container, filtration was carried out under reduced pressure at 70 °C, then vacuum drying was carried out at 70 °C for 12 hours, and natural cooling to room temperature was carried out to obtain a precursor powder of the electrolyte. 3) The treated electrolyte precursor powder was heat-treated at 600 °C for 4 hours under the protection of an inert atmosphere (argon gas), naturally cooled to room temperature, and pulverized to obtain a nano-sized Li 10 GeP₂S 12 and a composite sulfide solid electrolyte of Li₇P₂S₈I.

[0061] The prepared nano-sized sulfide solid electrolyte had a particle size of about 90 nm, and the room temperature ionic conductivity of the electrolyte was 9.38×10 -3 S / cm.

[0062] Using LiCoO₂ as the active material of the positive electrode, the mass ratio of LiCoO₂ in the composite positive electrode material was 83%, using the above electrolyte as the electrolyte layer, and metallic lithium as the negative electrode, a all-solid-state battery was assembled. The battery was stably cyclable 500 times at 1C, and the capacity retention rate was 91.5%.

[0063] Example 13 The sulfide solid electrolyte material of this example was obtained by the following preparation method. 1) Li₂S was prepared by the ball milling method. Specifically, dry sulfur powder and lithium hydride powder were mixed at a molar ratio of 1:2, placed in a ball mill pot, and ball milled at 500 r / min at room temperature for 12 hours to obtain lithium sulfide. 2) Mix 55 parts by weight of a mixed solution of hexene and ethanol (the volume ratio of hexene to ethanol is 3:2) with 0.01 part by weight of Triton. Then, add 1 part by weight of raw material (the molar mass ratio of Li2S, P2S5, and GeS2 is 5:1:1), shake and mix at 500 revolutions per minute in a container for 24 hours, then perform vacuum suction filtration at 70 °C, and then perform vacuum drying at 70 °C for 12 hours, and naturally cool to room temperature to obtain a precursor powder of the electrolyte. 3) Heat-treat the treated precursor powder of the electrolyte at 600 °C for 4 hours under the protection of an inert atmosphere (argon gas), naturally cool to room temperature, and pulverize to obtain a composite sulfide solid electrolyte of nano-sized Li 10 GeP2S 12 and Li7P2S8I.

[0064] The prepared nano-sized sulfide solid electrolyte has a particle size of about 60 nm, and the room temperature ionic conductivity of the electrolyte is 9.62×10 -3 S / cm.

[0065] Using LiCoO2 as the active material of the positive electrode, with the mass ratio of LiCoO2 in the composite positive electrode material being 90%, using the above electrolyte as the electrolyte layer, and using metallic lithium as the negative electrode, an all-solid-state battery was assembled. The battery can be stably cycled 1500 times at 1C, and the capacity retention rate is 90.5%.

[0066] Comparative Example 1 The sulfide solid electrolyte material of this comparative example has the chemical formula Li6PS5Cl, and its preparation method is different from that of Example 1 in that 2 parts by weight of absolute ethanol and 1 part by weight of raw material (the molar mass ratio of Li2S, P2S5, and LiCl is 5:1:2) are mixed in Comparative Example 1, and the rest is the same as that of Example 1.

[0067] The prepared sulfide solid electrolyte has a particle size of 5 μm, and the room temperature ionic conductivity of the electrolyte is 2×10 -3 S / cm.

[0068] Using LiCoO₂ as the active material of the positive electrode, with the mass ratio of LiCoO₂ in the composite positive electrode material being 70%, using the above electrolyte as the electrolyte layer, and using metallic lithium as the negative electrode, a all-solid-state battery was assembled. The battery could be stably cycled 100 times at 0.1C, and the capacity retention rate was 82%.

[0069] Comparative Example 2 The sulfide solid electrolyte material of this comparative example has the chemical formula Li₆PS₅Cl. Its preparation method is different from that of Example 1 in that no solvent was added to the raw materials in Comparative Example 2, and the rest is the same as that of Example 1.

[0070] The prepared sulfide solid electrolyte had a particle size of 10 - 50 μm, and the room-temperature ionic conductivity of the electrolyte was 2.2×10 -3 S / cm.

[0071] Using LiCoO₂ as the active material of the positive electrode, with the mass ratio of LiCoO₂ in the composite positive electrode material being 70%, using the above electrolyte as the electrolyte layer, and using metallic lithium as the negative electrode, a all-solid-state battery was assembled. The battery could be stably cycled 100 times at 0.1C, and the capacity retention rate was 80%.

[0072] Comparative Example 3 The sulfide solid electrolyte material of this comparative example is a composite sulfide solid electrolyte of Li 10 GeP₂S 12 and Li₇P₂S₈I. Its preparation method is different from that of Example 13 in that no dispersant (Triton) was added in Comparative Example 3, and the rest is the same as that of Example 13.

[0073] The prepared sulfide solid electrolyte had a particle size of about 10 μm, and the room-temperature ionic conductivity of the electrolyte was 7×10 -3 S / cm.

[0074] Using LiCoO₂ as the active material of the positive electrode, with the mass ratio of LiCoO₂ in the composite positive electrode material being 70%, using the above electrolyte as the electrolyte layer, and using metallic lithium as the negative electrode, a all-solid-state battery was assembled. The battery was stably cyclable 100 times at 0.1C, and the capacity retention rate was 83%.

[0075] Finally, it should be noted that the specific examples described in this specification are merely illustrative of the spirit of the present invention and do not limit the embodiments of the present invention. Those skilled in the technical field to which the present invention pertains can make various modifications, supplements, or replacements in a similar form to the specific examples described. Here, it is not necessary, nor possible, to list all embodiments. Those obvious changes and deformations derived from the essential spirit of the present invention still belong to the protection scope of the present invention, and interpreting them as any additional restrictions would be contrary to the spirit of the present invention.

Claims

1. A method for preparing a nano-sized sulfide solid electrolyte material, wherein the nano-sized sulfide solid electrolyte material has one or more of the chemical formulas shown in Formula I, Formula II, and Formula III, (100 - x - y)Li ２ S・xP ２ S ５ ・yM ｍ N ｎ Formula I where 0 ≦ x < 100, 0 ≦ y < 100, 0 ≦ x + y < 100, 0 ≦ m < 4, 0 ≦ n < 6, M is one or more of Li, Ge, Si, Sn, Sb, N is one or more of Se, O, Cl, Br, I, Li １０±ｌ Ge １－ｇ G ｇ P ２－ｑ Q ｑ S １２－ｗ W ｗ Formula II where 0 ≦ l < 1, 0 ≦ g ≦ 1, 0 ≦ q ≦ 2, 0 ≦ w < 1, G is Si and / or Sn, Q is Sb, W is one or more of O, Se, Cl, Br, I, Li ６±ｌ P １－ｅ E ｅ S ５±ｌ－ｒ R ｒ X １±ｌ Formula III where 0 ≦ l < 1, 0 ≦ e < 1, 0 ≦ r < 1, E is one or more of Ge, Si, Sn, Sb, R is O and / or Se, X is one or more of Cl, Br, I, the nano-sized sulfide solid electrolyte material has a size of 10 to 500 nm, the method for preparing the nano-sized sulfide solid electrolyte material is step 1) of preparing a lithium sulfide material, step 2) of mixing 10 to 100 parts by weight of a solvent, 0 to 1 part by mass of a dispersant, and 1 part by weight of a raw material containing a lithium sulfide material in a sealed container and drying to obtain an electrolyte precursor powder, and step 3) of heat-treating and pulverizing the electrolyte precursor powder obtained in step 2) to obtain a nano-sized sulfide solid electrolyte material. A method for preparing a nano-sized sulfide solid electrolyte material, characterized by comprising the above steps.

2. The nano-sized sulfide solid electrolyte material has a size of 10 to 100 nm. The method for preparing a nano-sized sulfide solid electrolyte material according to Claim 1, characterized by this.

3. The nano-sized sulfide solid electrolyte material has an ionic conductivity at room temperature of 1×10 －４ to 1×10 －１ S / cm, and is characterized in that it is a method for preparing the nano-sized sulfide solid electrolyte material according to claim 1.

4. The method for preparing a lithium sulfide material includes one or more of a ball milling method, a carbon thermal reduction method, lithiation of a sulfur-containing chemical substance, sulfidation of metal lithium nanoparticles, and interaction between a lithium-containing substance and a sulfur-containing substance. The preparation method according to Claim 1, characterized by this.

5. The solvent in step (2) is one or a combination of more than one of toluene, chlorobenzene, xylene, dimethyl carbonate, N-methylformamide, n-hexane, glyme, dibutyl ether, ethanol, 1,2-ethylenediamine, 1,2-ethanedithiol, acetonitrile, tetrahydrofuran, methanol, isopropyl ether, acetone, hexene, and ethyl acetate. The preparation method according to claim 1 is characterized by this.

6. The dispersant in step (2) is one or a combination of more than one of Triton X-100, sodium hexametaphosphate, sodium pyrophosphate, sodium tripolyphosphate, sodium dodecyl sulfate, ammonium lauryl sulfate, sodium lauryl ether sulfate, polyvinylpyrrolidone, Pluronic (registered trademark) F-127, Tween 80, and cetyltrimethylammonium bromide. The preparation method according to claim 1 is characterized by this.

7. In step (2), the mass part of the dispersant satisfies 0 < mass part of the dispersant ≤ 1. The preparation method according to claim 1 is characterized by this.

8. The mixing method in step (2) includes one or a combination of more than one of mechanical stirring, mechanical oscillation, ultrasonic dispersion, ball milling, and roll milling. The preparation method according to claim 1 is characterized by this.

9. The mixing time in step (2) is 1 to 48 hours. The preparation method according to claim 1 is characterized by this.

10. In step (2), the drying temperature is 10 to 100 °C and the drying time is 1 to 48 hours. The preparation method according to claim 1 is characterized by this.

11. In step (3), the heat treatment temperature is 100 to 600 °C and the heat treatment time is 0.5 to 24 hours. The preparation method according to claim 1 is characterized by this.

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