Glass ceramic sulfide electrolyte as well as preparation method and application thereof

Abstract

The embodiment of the invention provides a glass ceramic sulfide electrolyte as well as a preparation method and application thereof, and relates to the technical field of batteries. In the preparation method, Li2S, P2S5, WO3 and LiI are mixed in an inert gas environment to obtain precursor powder, then the precursor powder is subjected to amorphization treatment to obtain a solid electrolyte powder precursor, finally the solid electrolyte powder precursor is sintered in the inert gas environment to obtain the glass ceramic sulfide electrolyte # imgabs0 #, x is larger than or equal to 0.001 and smaller than or equal to 0.2, and 1t is larger than or equal to 0.001. Yt; Yt; and 0.9. Through the preparation method, the prepared glass ceramic sulfide electrolyte has low Young modulus, high ionic conductivity and good interface stability, and meets the requirements of low circulating pressure and low preparation pressure of an all-solid-state battery.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a glass-ceramic sulfide electrolyte and a preparation method and application thereof. Background Art

[0002] With the growing demand for high-performance energy storage devices in modern society, traditional liquid electrolyte batteries are gradually exposing limitations in terms of safety and energy density. Glass-ceramic sulfide electrolytes, however, offer high ionic conductivity and significantly improve battery safety, making them an ideal choice for batteries used in new energy vehicles and other energy storage applications.

[0003] In existing glass-ceramic sulfide electrolyte preparation technologies, element doping is typically used to improve electrolyte ionic conductivity while maintaining chemical interface stability. However, the glass-ceramic sulfide electrolytes prepared using existing doping techniques, such as single oxygen doping and single bromine doping, exhibit a high Young's modulus during all-solid-state battery cycling. This results in the need to apply pressures greater than MPa to maintain interfacial contact between the electrode materials, failing to meet the low cycling and preparation pressure requirements of all-solid-state batteries. Therefore, the Young's modulus of these electrolytes needs to be further reduced.

[0004] In summary, providing an element doping technology solution that simultaneously satisfies the requirements of low Young's modulus, high ionic conductivity and excellent interface stability for glass-ceramic sulfide electrolytes is a technical problem that needs to be solved urgently. Summary of the Invention

[0005] The embodiments of the present application provide a glass-ceramic sulfide electrolyte, a preparation method thereof, and an application thereof, so as to achieve the effect of simultaneously satisfying the requirements that the glass-ceramic sulfide electrolyte has low Young's modulus, high ionic conductivity, and excellent interface stability.

[0006] In a first aspect, the present invention provides a glass-ceramic sulfide electrolyte, wherein the molecular formula of the glass-ceramic sulfide electrolyte is (1-y)Li 3-x P 1-x W x S 4-3x O 3x -yLiI;

[0007] The value range of x is 0.001≦x≦0.2, and the value range of y is 0 <y<0.9。

[0008] In a possible implementation, the value range of x is 0.005≦x≦0.1, and the value range of y is 0.1≦y≦0.5.

[0009] In a second aspect, an embodiment of the present application provides a method for preparing a glass-ceramic sulfide electrolyte, the method comprising:

[0010] Li2S, P2S5, WO3, and LiI are mixed under an inert gas environment to obtain a precursor powder;

[0011] performing an amorphization treatment on the precursor powder to obtain a solid electrolyte powder precursor;

[0012] The solid electrolyte powder precursor is sintered in an inert gas environment to obtain a glass ceramic sulfide electrolyte.

[0013] In one possible embodiment, before mixing Li2S, P2S5, WO3, and LiI under an inert gas environment, the method further comprises: mixing Li2S, P2S5, WO3, and LiI in a molar ratio of Li2S, P2S5, WO3, and LiI were obtained by weighing.

[0014] In a possible implementation, the value range of x is 0.001≦x≦0.2, and the value range of y is 0 <y<0.9。

[0015] In a possible implementation, the value range of x is 0.005≦x≦0.1, and the value range of y is 0.1≦y≦0.5.

[0016] In a possible embodiment, the amorphization treatment of the precursor powder includes:

[0017] The precursor powder is placed in a ball milling jar and ball milled using a ball mill to obtain the solid electrolyte powder precursor.

[0018] In a possible implementation manner, during sintering, the sintering time is 1-20 hours, and the sintering temperature is 100-300°C.

[0019] In a possible embodiment, during the ball milling treatment, the ball milling time is 5-30 hours, and the ball milling speed is 100-800 rpm.

[0020] In a third aspect, an embodiment of the present application provides an all-solid-state battery, comprising: a glass-ceramic sulfide electrolyte as described in any possible aspect of the first aspect, and / or a glass-ceramic sulfide electrolyte prepared by any possible method described in the second aspect.

[0021] In a fourth aspect, an embodiment of the present application provides an electrical device, comprising a device body and the all-solid-state battery described in the third aspect.

[0022] A glass-ceramic sulfide electrolyte provided by an embodiment of the present application, its preparation method and application. By mixing Li2S, P2S5, WO3, and LiI in an inert gas environment, a precursor powder is obtained. Then, the precursor powder is subjected to an amorphization treatment to obtain a solid electrolyte powder precursor. Finally, the solid electrolyte powder precursor is sintered in an inert gas environment to obtain the glass-ceramic sulfide electrolyte (1-y)Li 3-x P 1-x W x S 4-3x O 3x -yLiI, where 0.001 ≦ x ≦ 0.2 and 0 < y < 0.9. Through the above preparation method, the prepared glass-ceramic sulfide electrolyte has a low Young's modulus, a high ionic conductivity, and good interfacial stability, meeting the requirements of low cycling pressure and low preparation pressure for all-solid-state batteries. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings here are incorporated into the specification and form a part of this specification, showing embodiments consistent with the present application, and are used together with the specification to explain the principles of the present application.

[0024] Figure 1 is a schematic flow chart of a preparation method of a glass-ceramic sulfide electrolyte provided by the present application.​​​​​​​​​​​​​Young's modulus: The Young's modulus of an electrolyte is a physical quantity used to measure the electrolyte material's ability to resist tensile or compressive deformation within its elastic range, reflecting the rigidity or hardness characteristics of the electrolyte material. Specifically, when an external force is applied to the electrolyte, causing it to elastically deform, the Young's modulus represents the proportional relationship between stress (force per unit area) and strain (relative degree of deformation). The higher the Young's modulus value, the less deformable the electrolyte material is. In other words, the material is harder and more rigid, better able to withstand external forces while maintaining its shape and structural stability. Conversely, the lower the Young's modulus value, the relatively softer the electrolyte material is, and the more easily it deforms when subjected to external forces.

[0029] The application background of this application is then explained as follows:

[0030] With the large-scale application of lithium-ion batteries in new energy vehicles and energy storage, all-solid-state batteries are attracting increasing attention due to their high safety and high energy density. Solid-state electrolytes mainly include sulfide electrolytes, oxide electrolytes, polymer electrolytes, and halide solid electrolytes. Among them, sulfide solid electrolytes are considered to be an ideal choice for optimizing all-solid-state batteries because they have ionic conductivity comparable to that of liquid electrolytes, low synthesis temperature, excellent mechanical ductility, and good interfacial contact, making them suitable for high-energy-density energy storage devices.

[0031] Furthermore, sulfide electrolytes can be divided into glass electrolytes, glass-ceramic electrolytes and crystalline electrolytes according to the crystal type. Crystalline electrolytes such as Li 5.5 PS 4.5 Cl 1.5 (10mS / cm), Li 10 GeP2S 12 (12mS / cm), Li 9.5 4Si 1.74 P 1.44 S 11.7 Cl 0.3 (25mS / cm), with very high ionic conductivity. However, on the one hand, this type of electrolyte has a relatively high Young's modulus, and all-solid-state batteries require pressures greater than MPa to maintain interfacial contact between electrode materials during cycling. On the other hand, this type of electrolyte has poor air stability and easily reacts with moisture in the air to produce toxic H2S gas. It also easily undergoes side reactions with lithium metal, placing stringent requirements on the preparation environment control, typically requiring an ambient dew point ≤-70°C, which is not conducive to large-scale batch production.

[0032] Glass-ceramic sulfide electrolytes have low ionic conductivity (less than 1 mS / cm). In existing glass-ceramic sulfide electrolyte preparation technologies, element doping technology is usually used to improve the electrolyte ionic conductivity while maintaining the stability of the chemical interface. However, the glass-ceramic sulfide electrolytes prepared by existing doping technologies, such as oxygen monodoping and bromine monodoping, have a high Young's modulus during the cycling process of all-solid-state batteries. Pressures greater than MPa are required to maintain interfacial contact between the electrode materials, which cannot meet the requirements of low cycling pressure and low preparation pressure of all-solid-state batteries. This not only increases the complexity and cost of the battery system, but also limits the flexibility and convenience of all-solid-state batteries in practical applications. Therefore, it is necessary to further reduce the Young's modulus of the electrolyte, which will help achieve lower operating pressures and simpler manufacturing processes without sacrificing ionic conductivity and chemical stability, thereby promoting the further development and application of all-solid-state battery technology.

[0033] In summary, providing an element doping technology solution that simultaneously satisfies the requirements of low Young's modulus, high ionic conductivity and excellent interface stability for glass-ceramic sulfide electrolytes is a technical problem that needs to be solved urgently.

[0034] Based on the above technical problems, the inventors found that by doping tungsten, oxygen and lithium iodide, the crystal structure of the electrolyte can be changed, which helps the migration of lithium ions and thus improves the ionic conductivity. At the same time, because tungsten is chemically stable, it can maintain the stability of the electrolyte chemical interface; iodine reacts with lithium atoms at the battery interface to form lithium iodide, which can effectively inhibit the growth of lithium dendrites and help improve the stability of the electrolyte to lithium metal; oxygen helps to improve the stability of the electrolyte to air. On the other hand, by introducing lithium iodide, it helps to reduce the Young's modulus of the solid electrolyte, maintain good solid-solid interface contact between the active material and the solid electrolyte, and extend the cycle life of the solid-state battery, meeting the requirements of all-solid-state batteries at low cycle pressure and low preparation pressure. Based on this, the present application provides a glass ceramic sulfide electrolyte, a preparation method and application thereof.

[0035] The following specific embodiments describe in detail the technical solution of the present application and how the technical solution of the present application solves the above-mentioned technical problems. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0036] Figure 1 A schematic diagram of a process for preparing a glass-ceramic sulfide electrolyte provided in this application is shown in FIG. Figure 1 As shown, the preparation method comprises:

[0037] S101: Li2S, P2S5, WO3, and LiI are mixed under an inert gas environment to obtain a precursor powder.

[0038] In this step, lithium sulfide Li2S is used as a lithium source material, which is often used to prepare solid electrolytes. It has good ionic conductivity and is one of the basic components of sulfide electrolytes. Phosphorus pentasulfide P2S5 is a sulfide compound, which is often used to synthesize sulfide electrolytes. Tungsten trioxide WO3 is a transition metal oxide. In battery materials, WO3 can be doped to enhance the conductivity and stability of the material. Lithium iodide LiI is a lithium salt with good ionic conductivity.

[0039] Specifically, Li2S, P2S5, WO3, and LiI are mixed in a glove box filled with an inert gas, such as argon, nitrogen, helium, or neon, to obtain a precursor powder, which provides the material basis for preparing a glass-ceramic sulfide electrolyte.

[0040] S102: performing amorphization treatment on the precursor powder to obtain a solid electrolyte powder precursor.

[0041] In this step, amorphization transforms the atomic or molecular arrangement of the precursor powder from an ordered crystalline structure to an amorphous state. This amorphous structure provides more channels for ion migration, reduces the barrier effect of grain boundaries, and improves overall ionic conductivity.

[0042] Specifically, the amorphization treatment of the precursor powder usually involves methods such as heating, rapid cooling or mechanical grinding to break the long-range ordered structure of the material, thereby forming an amorphous solid electrolyte powder precursor.

[0043] S103: Sintering the solid electrolyte powder precursor in an inert gas environment to obtain a glass ceramic sulfide electrolyte.

[0044] In this step, sintering refers to the process of heating the solid electrolyte powder precursor at a high temperature to a temperature close to its melting point to cause bonding and densification between the particles.

[0045] Specifically, the solid electrolyte powder precursor is placed in an inert gas environment, such as argon, nitrogen, helium, neon, etc., and is sintered at high temperature. By controlling the high temperature sintering time and high temperature sintering temperature, a glass ceramic sulfide electrolyte is finally obtained.

[0046] The present invention provides a method for preparing a glass-ceramic sulfide electrolyte. The method comprises mixing Li2S, P2S5, WO3, and LiI in an inert gas atmosphere to obtain a precursor powder. The precursor powder is then amorphized to obtain a solid electrolyte powder precursor. Finally, the solid electrolyte powder precursor is sintered in an inert gas atmosphere to obtain a glass-ceramic sulfide electrolyte. The glass-ceramic sulfide electrolyte prepared by this method exhibits low Young's modulus, high ionic conductivity, and good interfacial stability, meeting the low cycling pressure and low production pressure requirements of all-solid-state batteries.

[0047] exist Figure 1 Based on the embodiment, before S101, the preparation method of the glass ceramic sulfide electrolyte further includes: preparing a sulfide electrolyte according to the molar ratio of Li2S, P2S5, WO3, and LiI. Weigh Li2S, P2S5, WO3, and LiI. The value range of x is 0.001≦x≦0.2, and the value range of y is 0 <y<0.9。

[0048] x and y represent the doping levels and composition ratios of oxygen, tungsten, and lithium iodide, respectively. x can be 0.001, 0.002, 0.005, 0.01, 0.015, or 0.2, and y can be 0.001, 0.01, 0.1, 0.5, 0.8, or 0.8, etc. Exemplarily, before Li2S, P2S5, WO3, and LiI are mixed under an inert gas environment, when each material is weighed, Li2S, P2S5, WO3, and LiI are weighed at a molar ratio of 0.7495:0.2495:0.001:0.5; or Li2S, P2S5, WO3, and LiI are weighed at a molar ratio of 1.3991:0.4001:0.1998:0.001; or Li2S, P2S5, WO3, and LiI are weighed at a molar ratio of 0.29:0.09:0.02:0.8.

[0049] Furthermore, preferably, the value range of x is 0.005≦x≦0.1, and the value range of y is 0.1≦y≦0.5.

[0050] x may be 0.005, 0.01, 0.05 or 0.1, and y may be 0.1, 0.2, 0.33, 0.4 or 0.5, etc. For example, before mixing Li2S, P2S5, WO3, and LiI under an inert gas environment, each material is weighed to obtain Li2S, P2S5, WO3, and LiI in a molar ratio of 0.9715:0.3015:0.067:0.33; or Li2S, P2S5, WO3, and LiI in a molar ratio of 1.34775:0.44775:0.0045:0.1; or Li2S, P2S5, WO3, and LiI in a molar ratio of 0.7475:0.2475:0.005:0.5.

[0051] The specific values of x and y here, namely the molar ratios of Li2S, P2S5, WO3, and LiI (accurate to four decimal places), are used for example only and should be adjusted appropriately based on specific needs in actual applications. By weighing Li2S, P2S5, WO3, and LiI according to specific molar ratios, we provide a material foundation for the subsequent preparation of glass-ceramic sulfide electrolytes and enable the preparation of electrolyte materials that meet specific application requirements.

[0052] exist Figure 1 Based on the embodiment, in S102: performing amorphization treatment on the precursor powder specifically includes:

[0053] In a possible embodiment, the precursor powder is placed in a ball milling jar and ball milled using a ball mill to obtain a solid electrolyte powder precursor.

[0054] As described in S102, the amorphization treatment of the precursor powder usually involves methods such as heating, rapid cooling or mechanical grinding. Among them, mechanical grinding usually controls the ball milling speed and ball milling time of the ball mill so that the precursor powder continuously collides and rubs the powder particles, thereby introducing a large amount of mechanical energy, further breaking the crystal structure of the material, causing it to transform from a crystalline state to an amorphous state, thereby providing more ion migration channels, reducing the obstruction effect of grain boundaries, and improving ion conductivity.

[0055] In a possible embodiment, during the ball milling treatment, the ball milling time is 5-30 hours, and the ball milling speed is 100-800 rpm.

[0056] The ball milling time refers to the duration of grinding of the precursor powder in the ball mill. Longer ball milling times generally result in more complete mechanical energy transfer, which makes it easier to destroy the lattice structure of the precursor powder, thereby achieving amorphization. However, excessively long ball milling times may also lead to excessive particle refinement or the introduction of impurities. Exemplary ball milling times can be 5 hours, 10 hours, 15 hours, 20 hours, 25 hours, or 30 hours.

[0057] The ball milling speed refers to the rotational speed of the ball mill, usually expressed in revolutions per minute. A higher ball milling speed increases the kinetic energy of the milled precursor powder, thereby enhancing the impact and friction effects on the powder, accelerating the amorphization process and particle refinement; however, too high a ball milling speed may also lead to excessive heat accumulation or ball mill wear. Exemplary ball milling speeds can be 100 rpm, 300 rpm, 500 rpm, 700 rpm, or 800 rpm.

[0058] During the ball milling process, the proper selection of the ball milling time and ball milling speed can effectively control the particle size, morphology, and phase composition of the material to meet specific application requirements. The specific values of the ball milling time and ball milling speed are used here for example only and are not limited in this application.

[0059] exist Figure 1 Based on the embodiment, in S103: when the solid electrolyte powder precursor is sintered in an inert gas environment, the sintering time is 1-20 hours and the sintering temperature is 100-300°C.

[0060] Sintering time refers to the time the solid electrolyte powder precursor is held at high temperature. Longer sintering times generally allow more time for diffusion and bonding between solid electrolyte powder precursor particles, thereby improving the material's density and mechanical strength. However, excessively long sintering times can result in excessively large grains, affecting the material's microstructure and performance. For example, sintering times can be 1 hour, 5 hours, 10 hours, 15 hours, or 20 hours.

[0061] The sintering temperature refers to the maximum temperature reached by the solid electrolyte powder precursor during the sintering process. Higher sintering temperatures generally accelerate the diffusion and sintering process of the solid electrolyte powder precursor particles, improving the material's densification and electrical conductivity. However, excessively high sintering temperatures may cause the material to decompose or undergo phase transitions, affecting its chemical stability and structural integrity. For example, the sintering temperature can be 100°C, 150°C, 200°C, 250°C, or 300°C.

[0062] In practical applications, shorter sintering times are usually combined with higher sintering temperatures to balance the relationship between rapid densification and material stability. The specific values of sintering temperature and sintering time are only used as examples and are not limited in this application.

[0063] The present application provides a glass ceramic sulfide electrolyte, the molecular formula of which is , where the value range of x is 0.001≦x≦0.2, and the value range of y is 0 <y<0.9。

[0064] pass Figure 1 The method described in the embodiment is used to prepare the molecular formula The glass-ceramic sulfide electrolyte is constructed using a molten-liquid electrolyte. Here, x and y represent the doping levels and composition ratios of oxygen, tungsten, and lithium iodide, respectively. By adjusting the values of x and y, the proportions of each element in the glass-ceramic sulfide electrolyte can be adjusted, further optimizing material properties.

[0065] Furthermore, preferably, the value range of x is 0.005≦x≦0.1, and the value range of y is 0.1≦y≦0.5.

[0066] The value of x can be 0.005, 0.01, 0.05 or 0.1, and the value of y can be 0.1, 0.2, 0.33, 0.4 or 0.5, etc. For example, by Figure 1 The molecular formula of the glass-ceramic sulfide electrolyte prepared by the method described in the embodiment can be 0.67Li 2.9 P 0.9 W 0.1 S 3.7 O 0.3 -0.33LiI, 0.9Li 2.995 P 0.995 W 0.005 S 3.985 O 0.015 -0.1LiI or 0.5Li 2.99 P 0.99 W 0.01 S 3.97 O 0.03 -0.5LiI, etc.

[0067] pass Figure 1 The glass-ceramic sulfide electrolyte prepared by the method described in the embodiment has the advantages of low Young's modulus, high ionic conductivity and excellent interface stability, and meets the requirements of low cycle pressure and low preparation pressure of all-solid-state batteries.

[0068] The present application also provides an all-solid-state battery, comprising: Figure 1 The glass-ceramic sulfide electrolyte prepared by the method described in the embodiment, and / or the glass-ceramic sulfide electrolyte described in the previous embodiment.

[0069] The present application also provides an electrical device, comprising: a device main body and the all-solid-state battery described in the previous embodiment.

[0070] Exemplarily, the electrical equipment may be a vehicle, a mobile electronic device, a drone, an aircraft, etc. The above-mentioned electrical equipment uses the all-solid-state battery to provide stable and long-lasting power support, so that the electrical equipment has higher safety and endurance.

[0071] The glass-ceramic sulfide electrolyte provided in this application, its preparation method and application will be specifically introduced through specific examples below.

[0072] Unless otherwise specified, the reagents, materials, and instruments used in the following examples are conventional reagents, conventional materials, and conventional instruments in the art and can be obtained commercially. The reagents involved can also be synthesized by conventional methods in the art.

[0073] Example 1

[0074] This embodiment provides a glass ceramic sulfide electrolyte, the molecular formula of the glass ceramic sulfide electrolyte is 0.67Li 2.999 P 0.999 W 0.001 S 3.997 O 0.003 -0.33LiI, the preparation method thereof comprises the following steps:

[0075] (1) Li2S, P2S5, WO3, and LiI were placed in an argon-filled glove box at a molar ratio of 1.0047:0.3347:0.00067:0.33 and manually mixed in a mortar for 30 min to obtain a precursor powder;

[0076] (2) placing the precursor powder obtained in step (1) in a ball mill, and using a planetary ball mill at a speed of 600 rpm for 24 h to obtain an amorphous solid electrolyte powder precursor;

[0077] (3) The amorphous solid electrolyte powder precursor obtained in step (2) was placed in a muffle furnace under an inert gas environment and sintered at 260°C for 5 hours to obtain a 0.67Li 2.999 P 0.999 W 0.001 S 3.997 O 0.003 -0.33LiI glass-ceramic sulfide electrolyte.

[0078] Example 2

[0079] This embodiment provides a glass ceramic sulfide electrolyte, the molecular formula of the glass ceramic sulfide electrolyte is 0.67Li 2.99 P 0.99 W 0.01 S3.97 O 0.03 -0.33LiI, the preparation method is basically the same as that of Example 1, except that: in step (1): Li2S, P2S5, WO3, and LiI are placed in a glove box filled with argon at a molar ratio of 1.0017:0.3317:0.0067:0.33, and manually mixed in a mortar for 30 minutes to obtain a precursor powder. The final product is a molecular formula of 0.67Li 2.99 P 0.99 W 0.01 S 3.97 O 0.03 -0.33LiI glass-ceramic sulfide electrolyte.

[0080] Example 3

[0081] This embodiment provides a glass ceramic sulfide electrolyte, the molecular formula of the glass ceramic sulfide electrolyte is 0.67Li 2.9 P 0.9 W 0.1 S 3.7 O 0.3 -0.33LiI, the preparation method is basically the same as that of Example 1, except that: in step (1): Li2S, P2S5, WO3, and LiI are placed in a glove box filled with argon at a molar ratio of 0.9715:0.3015:0.067:0.33, and manually mixed in a mortar for 30 minutes to obtain a precursor powder. The final product is a precursor with a molecular formula of 0.67Li 2.9 P 0.9 W 0.1 S 3.7 O 0.3 -0.33LiI glass-ceramic sulfide electrolyte.

[0082] Example 4

[0083] This embodiment provides a glass ceramic sulfide electrolyte, the molecular formula of the glass ceramic sulfide electrolyte is 0.67Li 2.9 P 0.995 W 0.005 S 3.985 O 0.015 -0.33LiI, the preparation method is basically the same as that of Example 1, except that: in step (1): Li2S, P2S5, WO3, and LiI are placed in a glove box filled with argon at a molar ratio of 1.003325:0.333325:0.00335:0.33, and manually mixed in a mortar for 30 minutes to obtain a precursor powder. The final product is a precursor with a molecular formula of 0.67Li 2.9 P 0.995 W 0.005S 3.985 O 0.015 -0.33LiI glass-ceramic sulfide electrolyte.

[0084] Example 5

[0085] This embodiment provides a glass ceramic sulfide electrolyte, the molecular formula of the glass ceramic sulfide electrolyte is 0.67Li 2.9 P 0.8 W 0.2 S 3.4 O 0.6 -0.33LiI, the preparation method is basically the same as that of Example 1, except that: in step (1): Li2S, P2S5, WO3, and LiI are placed in a glove box filled with argon at a molar ratio of 0.938:0.268:0.134:0.33, and manually mixed in a mortar for 30 minutes to obtain a precursor powder. The final product is 0.67Li 2.9 P 0.8 W 0.2 S 3.4 O 0.6 -0.33LiI glass-ceramic sulfide electrolyte.

[0086] Example 6

[0087] This embodiment provides a glass ceramic sulfide electrolyte, the molecular formula of the glass ceramic sulfide electrolyte is 0.9Li 2.99 P 0.99 W 0.01 S 3.97 O 0.03 -0.1LiI, the preparation method is basically the same as that of Example 1, except that: in step (1): Li2S, P2S5, WO3, and LiI are placed in a glove box filled with argon at a molar ratio of 1.3455:0.4455:0.009:0.1, and manually mixed in a mortar for 30 minutes to obtain a precursor powder. The final product is a precursor with a molecular formula of 0.9Li 2.99 P 0.99 W 0.01 S 3.97 O 0.03 -0.1LiI glass-ceramic sulfide electrolyte.

[0088] Example 7

[0089] This embodiment provides a glass ceramic sulfide electrolyte, the molecular formula of the glass ceramic sulfide electrolyte is 0.8Li 2.99 P 0.99 W 0.01 S 3.97 O 0.03-0.2LiI, the preparation method is basically the same as that of Example 1, except that: in step (1): Li2S, P2S5, WO3, and LiI are placed in a glove box filled with argon at a molar ratio of 1.196:0.396:0.008:0.2, and manually mixed in a mortar for 30 minutes to obtain a precursor powder. The final product is a precursor with a molecular formula of 0.8Li 2.99 P 0.99 W 0.01 S 3.97 O 0.03 -0.2LiI glass-ceramic sulfide electrolyte.

[0090] Example 8

[0091] This embodiment provides a glass ceramic sulfide electrolyte, the molecular formula of the glass ceramic sulfide electrolyte is 0.5Li 2.99 P 0.99 W 0.01 S 3.97 O 0.03 -0.5LiI, the preparation method is basically the same as that of Example 1, except that: in step (1): Li2S, P2S5, WO3, and LiI are placed in a glove box filled with argon at a molar ratio of 0.7475:0.2475:0.005:0.5, and manually mixed in a mortar for 30 minutes to obtain a precursor powder. The final product is 0.5LiI 2.99 P 0.99 W 0.01 S 3.97 O 0.03 -0.5LiI glass-ceramic sulfide electrolyte.

[0092] Example 9

[0093] This embodiment provides a glass ceramic sulfide electrolyte, the molecular formula of the glass ceramic sulfide electrolyte is 0.5Li 2.999 P 0.999 W 0.001 S 3.997 O 0.003 -0.5LiI, the preparation method is basically the same as that of Example 1, except that: in step (1): Li2S, P2S5, WO3, and LiI are placed in a glove box filled with argon at a molar ratio of 0.74975:0.24975:0.0005:0.5, and manually mixed in a mortar for 30 minutes to obtain a precursor powder. The final product is a 0.5LiI 2.999 P 0.999 W 0.001 S 3.997 O 0.003 -0.5LiI glass-ceramic sulfide electrolyte.

[0094] Example 10

[0095] This embodiment provides a glass ceramic sulfide electrolyte, the molecular formula of the glass ceramic sulfide electrolyte is 0.5Li 2.9 P 0.9 W 0.1 S 3.7 O 0.3 -0.5LiI, the preparation method is basically the same as that of Example 1, except that: in step (1): Li2S, P2S5, WO3, and LiI are placed in a glove box filled with argon at a molar ratio of 0.725:0.225:0.05:0.5, and manually mixed in a mortar for 30 minutes to obtain a precursor powder. The final product is a 0.5LiI 2.9 P 0.9 W 0.1 S 3.7 O 0.3 -0.5LiI glass-ceramic sulfide electrolyte.

[0096] Example 11

[0097] This embodiment provides a glass ceramic sulfide electrolyte, the molecular formula of the glass ceramic sulfide electrolyte is 0.999Li 2.9 P 0.9 W 0.1 S 3.7 O 0.3 -0.001LiI, the preparation method is basically the same as that of Example 1, except that: in step (1): Li2S, P2S5, WO3, and LiI are placed in a glove box filled with argon at a molar ratio of 1.44855:0.44955:0.0999:0.001, and manually mixed in a mortar for 30 minutes to obtain a precursor powder. The final product is a precursor with a molecular formula of 0.999Li 2.9 P 0.9 W 0.1 S 3.7 O 0.3 -0.001LiI glass-ceramic sulfide electrolyte.

[0098] Example 12

[0099] This embodiment provides a glass ceramic sulfide electrolyte, the molecular formula of the glass ceramic sulfide electrolyte is 0.2Li 2.9 P 0.9 W 0.1 S 3.7 O 0.3-0.8LiI, the preparation method is basically the same as that of Example 1, except that: in step (1): Li2S, P2S5, WO3, and LiI are placed in a glove box filled with argon at a molar ratio of 0.29:0.09:0.02:0.8, and manually mixed in a mortar for 30 minutes to obtain a precursor powder. The final product is 0.2Li 2.9 P 0.9 W 0.1 S 3.7 O 0.3 -0.8LiI glass-ceramic sulfide electrolyte.

[0100] Comparative Example

[0101] This embodiment provides a glass-ceramic sulfide electrolyte having a molecular formula of Li3PS4. The preparation method is substantially the same as that of Example 1, except that in step (1), Li2S and P2S5 are placed in an argon-filled glove box at a molar ratio of 3:1 and manually mixed in a mortar for 30 minutes to obtain a precursor powder. Finally, a glass-ceramic sulfide electrolyte having a molecular formula of Li3PS4 is obtained.

[0102] Test Example 1

[0103] Ionic conductivity testing: 100 mg of the glass-ceramic sulfide electrolyte powder prepared in the above example was weighed and placed in a mold. A pressure of 360 MPa was applied to press the powder into a dense electrolyte sheet. Under pressure, the sample was subjected to electrochemical impedance spectroscopy (EIS) at room temperature (25°C) using an electrochemical workstation. The effective impedance value corresponding to the minimum absolute value of the impedance phase angle was used as the real part. The ionic conductivity of the glass-ceramic sulfide electrolyte was calculated based on this effective impedance value. The ionic conductivity test results are shown in Table 1.

[0104] Test Example 2

[0105] All-solid-state battery stability test for lithium metal: 100 mg of the glass-ceramic sulfide electrolyte powder prepared in the above example was weighed and placed in a mold. A pressure of 360 MPa was applied to press the electrolyte powder into a dense electrolyte sheet. Then, a 50 mm thick electrolyte sheet was placed on both sides of the electrolyte sheet. The lithium sheets were combined to form an all-solid-state lithium symmetric battery. The cycle time of this battery was recorded under a constant current test condition of 0.1 mA / cm². The results of the all-solid-state battery stability test on lithium metal are shown in Table 2.

[0106] Test Example 3

[0107] Air Stability Test: After the ionic conductivity test of the glass-ceramic sulfide electrolyte powder described in the above examples was completed, a 100 mg sample of the electrolyte powder was placed in an environment with a temperature of 25±3°C and a dew point of ≤-55°C for 3 hours. After the idling period, the electrolyte ionic conductivity was retested, and the ionic conductivity retention ratio was calculated. The air stability test results are shown in Table 3.

[0108] Test Example 4

[0109] The cycle performance test of the all-solid-state battery including the glass ceramic sulfide electrolyte described in the above embodiment was carried out: in an argon glove box, the target electrolyte, the positive electrode active material Li (Ni 0.8 Co 0.1 Mn 0.1 )O2(NCM811) were weighed at a weight ratio of 20:80. They were ground evenly using an agate mortar to produce a composite positive electrode material. In an insulating outer cylinder with a diameter of 10 mm, 14 mg of the above-mentioned composite positive electrode material and 70 mg of sulfide electrolyte were layered. It was press-formed at a pressure of 360 MPa to obtain a positive electrode and a solid electrolyte layer. Next, a piece of aluminum foil was stacked on the positive electrode side to form a current collector on the positive electrode side. Then, on the opposite side of the solid electrolyte layer that was in contact with the positive electrode, a film with a thickness and a diameter of 200 mm was placed. and a 10mm lithium sheet as the negative electrode material. It is press-formed at a pressure of 80MPa to produce a stack consisting of a positive electrode, a solid electrolyte layer and a negative electrode. Then, stainless steel collectors are placed above and below the stack, and collector leads are attached to the collectors. The assembled solid-state battery was subjected to a cycle performance test under the following test conditions: a current density of 1C and a voltage range of 2.7-4.3V (Li+ / Li). The cycle performance test results of the all-solid-state battery are shown in Table 4.

[0110] Table 1 Test results of ionic conductivity

[0111]

[0112] According to Table 1, the following conclusions can be drawn:

[0113] Compared with the comparative example, Examples 1 to 12 show that the ionic conductivity of the glass-ceramic sulfide electrolyte is between 1.13mS / cm and 2.06mS / cm through the element doping technology of tungsten, oxygen and lithium iodide, which is much higher than the ionic conductivity of 0.47mS / cm of the glass-ceramic sulfide electrolyte without tungsten, oxygen and lithium iodide in the comparative example. This is because the crystal structure of the glass-ceramic sulfide electrolyte is changed by doping with tungsten and oxygen, which facilitates the migration of lithium ions and thus improves the ionic conductivity, fully verifying the promoting effect of doping with tungsten, oxygen and lithium iodide on improving ionic conductivity. The glass-ceramic sulfide electrolyte and its preparation method provided by this application meet the requirements of ionic conductivity of glass-ceramic sulfide electrolyte in all-solid-state batteries.

[0114] Table 2 All-solid-state battery stability test results for lithium metal

[0115]

[0116] The battery is at 0.1mA / cm 2 Under constant current test conditions, a longer cycle time when the electrolyte is in contact with the battery indicates that the electrolyte has good lithium stability. Conversely, a shorter cycle time usually indicates that the electrolyte has poor lithium stability, because the electrolyte is prone to continuous side reactions when in contact with lithium metal, resulting in the formation of an unstable solid electrolyte interface layer at the interface or inducing corrosion of the lithium metal.

[0117] According to Table 2, the following conclusions can be drawn:

[0118] Compared to the comparative example, Examples 1 to 12 show that the cell cycle time of the glass-ceramic sulfide electrolyte in contact with the battery is between 592 hours and 911 hours through the element doping technology of tungsten, oxygen, and lithium iodide. In the comparative example, the cell cycle time of the glass-ceramic sulfide electrolyte without tungsten, oxygen, and lithium iodide in contact with the battery is only 351 hours. This shows that by doping with tungsten, oxygen, and lithium iodide, the stability of the interface between the glass-ceramic sulfide electrolyte and lithium metal can be effectively improved, fully verifying the promoting effect of tungsten, oxygen, and lithium iodide doping on improving cycle stability. The glass-ceramic sulfide electrolyte and its preparation method provided by this application meet the high energy density requirements of all-solid-state batteries.

[0119] Table 3 Air stability test results

[0120]

[0121] The retention rate is the ratio of the re-measured ionic conductivity of a glass-ceramic sulfide electrolyte to the initial ionic conductivity. It measures the retention of ionic conductivity after a period of stabilization under specific environmental conditions and reflects the electrolyte's stability in that environment. Higher post-exposure ionic conductivity and retention rate indicate closer re-measured ionic conductivity to the initial ionic conductivity. This indicates a smaller decrease in ionic conductivity after stabilization in a specific environment (here, air). This indicates that the electrolyte's ionic conductivity remains stable in air, and its internal structure and ion transport mechanisms are less affected by air. Consequently, the electrolyte maintains its ionic conductivity remarkably in air, indicating good air stability. The post-exposure ionic conductivity also provides a direct reflection of the electrolyte's ionic conductivity after exposure to air, corroborating the retention rate and demonstrating its stability in air.

[0122] According to Table 3, the following conclusions can be drawn:

[0123] Compared with the comparative example, Examples 1 to 12 show that through the element doping technology of tungsten, oxygen and lithium iodide, the ionic conductivity of the glass-ceramic sulfide electrolyte after exposure is between 0.91mS / cm-1.89mS / cm, and the retention rate is between 78.99%-91.75%. In the comparative example, the ionic conductivity and retention rate of the glass-ceramic sulfide electrolyte without tungsten, oxygen and lithium iodide after exposure are only 0.25mS / cm and 53.19%, respectively, further verifying the promoting effect of tungsten, oxygen and lithium iodide doping on improving ionic conductivity and air stability. The glass-ceramic sulfide electrolyte and its preparation method provided by this application reduce the environmental requirements for the use of the glass-ceramic sulfide electrolyte, thereby reducing the production cost of all-solid-state batteries.

[0124] Table 4 Cycling performance test results of all-solid-state batteries

[0125]

[0126] First efficiency refers to the ratio of the discharge capacity to the charge capacity of an all-solid-state battery during its first charge and discharge cycle, reflecting the charge and discharge efficiency of the battery when it is first used. A higher first efficiency indicates better energy utilization efficiency during the first charge and discharge. The 100-cycle capacity retention rate refers to the ratio of the discharge capacity of an all-solid-state battery after 100 charge and discharge cycles to the discharge capacity of the battery's first charge and discharge cycle. It measures the capacity attenuation of the battery after multiple cycles of use. A higher 100-cycle capacity retention rate means that the battery can still better maintain its initial discharge capacity after 100 cycles, and the battery's cycle stability and durability are also better.

[0127] By reducing the Young's modulus, the electrolyte can better adapt to the deformation of the electrode material under low pressure, thereby reducing the interfacial impedance and improving the initial efficiency. At the same time, reducing the Young's modulus helps all-solid-state batteries maintain a stable contact between the electrolyte and the electrode material during the cycle, reducing the capacity decay caused by poor interface.

[0128] According to Table 4, the following conclusions can be drawn:

[0129] Compared with the comparative example, Examples 1 to 12 show that through the element doping technology of tungsten, oxygen and lithium iodide, the first efficiency and 100-cycle capacity retention rates of the all-solid-state battery are between 81.50%-87.10% and between 74.30%-91.20%, respectively. In the comparative example, the first efficiency and 100-cycle capacity retention rates of the all-solid-state battery corresponding to the glass-ceramic sulfide electrolyte not doped with tungsten, oxygen and lithium iodide are only 76.30% and 67.70%, respectively. This verifies that relying solely on high-modulus rigid electrolytes is difficult to adapt to the low-pressure conditions in actual working conditions, and is prone to performance degradation due to interface contact degradation. It is confirmed that the doping of tungsten, oxygen and lithium iodide can achieve high cycle stability under the premise of reducing the Young's modulus of the electrolyte, maintain good solid-solid interface contact between the material and the glass-ceramic sulfide electrolyte, and extend the cycle life of the all-solid-state battery, while meeting the compatibility requirements of the all-solid-state battery for low preparation pressure and low cycle pressure.

[0130] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A glass ceramic sulfide electrolyte, characterized in that: The molecular formula of the glass-ceramic sulfide electrolyte is (1-y)Li 3-x P 1-x W x S 4-3x O 3x -yLiI; The value range of x is 0.001≦x≦0.2, and the value range of y is 0 <y<0.9。 2. The glass-ceramic sulfide electrolyte according to claim 1, characterized in that The value range of x is 0.005≦x≦0.1, and the value range of y is 0.1≦y≦0.

5.

3. A method for preparing a glass ceramic sulfide electrolyte, characterized in that: The method comprises: Li2S, P2S5, WO3, and LiI are mixed under an inert gas environment to obtain a precursor powder; performing an amorphization treatment on the precursor powder to obtain a solid electrolyte powder precursor; The solid electrolyte powder precursor is sintered in an inert gas environment to obtain a glass ceramic sulfide electrolyte.

4. The method according to claim 3, characterized in that Before mixing Li2S, P2S5, WO3 and LiI under an inert gas environment, the method further comprises: mixing Li2S, P2S5, WO3 and LiI in a molar ratio of Li2S, P2S5, WO3, and LiI were obtained by weighing.

5. The method according to claim 3, characterized in that The value range of x is 0.001≦x≦0.2, and the value range of y is 0 <y<0.9。 6. The method according to claim 5, characterized in that The value range of x is 0.005≦x≦0.1, and the value range of y is 0.1≦y≦0.

5.

7. The method according to any one of claims 3 to 6, characterized in that The amorphization treatment of the precursor powder comprises: The precursor powder is placed in a ball milling jar and ball milled using a ball mill to obtain the solid electrolyte powder precursor.

8. The method according to any one of claims 3 to 6, characterized in that During sintering, the sintering time is 1-20 hours, and the sintering temperature is 100-300°C.

9. The method according to claim 7, characterized in that During the ball milling treatment, the ball milling time is 5-30 hours, and the ball milling speed is 100-800 rpm.

10. An all-solid-state battery, characterized in that: include: The glass-ceramic sulfide electrolyte according to claim 1 or 2, and / or the glass-ceramic sulfide electrolyte prepared by the method according to any one of claims 3 to 9.

11. An electrical device, characterized in that: It comprises a device body and the all-solid-state battery according to claim 10.

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