Glass ceramic sulfide electrolyte, preparation method and solid-state battery

Abstract

The embodiment of the invention provides a glass ceramic sulfide electrolyte, a preparation method and a solid-state battery. The method comprises the following steps: in an inert atmosphere environment, weighing Li2S, Sb2S3, MeSa, LiI and S according to a molar ratio of (1.5-0.5 x-y): 0.5 x: (1-x): y: (2.5-a + ax-x); the preparation method comprises the following steps: carrying out ball milling treatment on the weighed Li2S, Sb2S3, MeSa, LiI and S to obtain a non-crystallized solid electrolyte powder precursor; and sintering the non-crystallized solid electrolyte powder precursor in an inert atmosphere to obtain the glass ceramic sulfide electrolyte. Wherein the value range of x is 0 lt; xlt; the value range of y is 0 lt; yt; Yt; and a is 1, 1.5 or 2. According to the technical scheme, the prepared glass ceramic sulfide electrolyte can improve the ionic conductivity on the premise of keeping high stability.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of solid-state batteries, in particular to a glass-ceramic sulfide electrolyte, a preparation method and a solid-state battery. BACKGROUND

[0002] With the large-scale application of lithium ion batteries in new energy vehicles and energy storage systems, the safety problems caused by thermal runaway have attracted widespread attention. Solid-state batteries (especially all-solid-state batteries) have higher safety and potential high energy density because they use solid-state electrolytes instead of liquid electrolytes, and have become a research hotspot.

[0003] At present, sulfide solid-state electrolytes are the mainstream solid-state electrolytes. Among them, some sulfide electrolytes have high ionic conductivity, such as Li 5.5 PS 4.5 Cl 1.5 , Li 10 GeP2S 12 and Li 9.54 Si 1.74 P 1.44 S 11.7 Cl 0.3 , but the air stability of this part of sulfide electrolytes is poor; some sulfide electrolytes have high air stability, such as Li4SnS4 and Li3SbS4, but the ionic conductivity of this part of sulfide electrolytes is low.

[0004] That is to say, there is a prominent contradiction between the ionic conductivity and stability of the current sulfide solid-state electrolyte, and how to simultaneously improve the ionic conductivity and stability of the sulfide solid-state electrolyte is a problem to be solved. SUMMARY

[0005] The embodiments of the present application provide a glass-ceramic sulfide electrolyte, a preparation method and a solid-state battery, so as to achieve the technical effect of simultaneously improving the ionic conductivity and stability of the sulfide solid-state electrolyte.

[0006] In a first aspect, the embodiments of the present application provide a glass-ceramic sulfide electrolyte, the chemical general formula of the glass-ceramic sulfide electrolyte is Li 3-x-y Sb x Me 1-x S 4-y I y ;

[0007] Among them, the Me is a metal element, the value range of x is 0

[0008] In a possible implementation, the Me includes at least one of the following: W, Mn, Y, Cr, In, Bi, Sc, Zn, Cu, Ca, and Ba.

[0009] In a possible implementation, the value range of x is 0.02 ≤ x ≤ 0.6, and / or the value range of y is 0.1 ≤ y ≤ 0.5.

[0010] In a second aspect, an embodiment of the present application provides a preparation method for a glass-ceramic sulfide electrolyte. This preparation method is used to prepare the glass-ceramic sulfide electrolyte as shown in the first aspect and / or various possible implementations of the first aspect above. The preparation method includes:

[0011] Under an inert atmosphere environment, Li2S, Sb2S3, MeS a , LiI, and S are weighed according to the molar ratio of (1.5 - 0.5x - y): 0.5x: (1 - x): y: (2.5 - a + ax - x), where the value range of x is 0 < x < 1, the value range of y is 0 < y < 1, and a is 1, 1.5, or 2;

[0012] The weighed Li2S, Sb2S3, MeS a , LiI, and S are ball-milled to obtain an amorphous solid electrolyte powder precursor;

[0013] The amorphous solid electrolyte powder precursor is sintered under the inert atmosphere to obtain the glass-ceramic sulfide electrolyte.

[0014] In a possible implementation, the ball-milling speed of the ball-milling process is 100 - 800 rpm and / or the ball-milling duration is 2 - 30 h.

[0015] In a possible implementation, the sintering temperature of the sintering process is 200 - 500 °C and / or the sintering duration is 1 - 20 h.

[0016] In a possible implementation, the step of ball-milling the weighed Li2S, Sb2S3, MeS a , LiI, and S to obtain an amorphous solid electrolyte powder precursor includes:

[0017] The weighed Li2S, Sb2S3, MeS a , LiI, and S are mixed through a mortar to obtain a precursor powder;

[0018] The precursor powder is ball-milled to obtain the amorphous solid electrolyte powder precursor.

[0019] In a possible implementation, the ball milling treatment on the precursor powder to obtain the amorphous solid electrolyte powder precursor comprises:

[0020] The precursor powder is added into a ball milling tank for sealing treatment, and the precursor powder is ball milled by using a planetary ball mill to obtain the amorphous solid electrolyte powder precursor.

[0021] In a possible implementation, the gas in the inert atmosphere is at least one of argon, nitrogen and helium.

[0022] In a third aspect, the embodiments of the present application provide a solid-state battery, comprising: a positive electrode, a negative electrode and a glass-ceramic sulfide electrolyte.

[0023] The glass-ceramic sulfide electrolyte is the glass-ceramic sulfide electrolyte as described in the first aspect and / or various possible implementations of the first aspect, or is prepared by the preparation method as described in the second aspect and / or various possible implementations of the second aspect.

[0024] The glass-ceramic sulfide electrolyte, the preparation method and the solid-state battery provided by the embodiments of the present application, in the method, under an inert atmosphere, Li2S, Sb2S3, MeS a , Lil and S are weighed according to a molar ratio of (1.5-0.5x-y):0.5x:(1-x):y:(2.5-a+ax-x). The weighed Li2S, Sb2S3, MeS a , Lil and S are ball milled to obtain an amorphous solid electrolyte powder precursor. The amorphous solid electrolyte powder precursor is sintered under an inert atmosphere to obtain a glass-ceramic sulfide electrolyte. In this technical solution, on the basis of the existing glass-ceramic sulfide electrolyte (Li3SbS4 system), the high stability characteristics of itself are retained, and the ion conductivity is improved by doping I elements and metal elements Me. At the same time, the doping of I elements can also improve the stability to lithium metal, meet the demand of improving the energy density of the all-solid-state battery, and the doping of metal elements Me stabilizes the battery interface, further improves the stability of the glass-ceramic sulfide electrolyte. BRIEF DESCRIPTION OF DRAWINGS

[0025] The accompanying drawings, which are incorporated into and form part of the specification, illustrate embodiments consistent with the present application and, together with the specification, serve to explain the principles of the application.

[0026] Figure 1A flowchart of a method for preparing a glass-ceramic sulfide electrolyte according to the present application is provided.

[0027] The specific embodiments of the present application have been shown by way of example in the above figures, and will be described in more detail below. These figures and this written description are not intended to limit the scope of the inventive concept in any way, but rather to illustrate the inventive concept to one of ordinary skill in the art by reference to specific embodiments. DETAILED DESCRIPTION

[0028] Exemplary embodiments will be described in detail herein with reference to the attached drawings. The description of the exemplary embodiments is intended to apply to any embodiment of the application, unless specified otherwise. It should be understood that every embodiment need not necessarily include all of the features shown in the drawings or all of the components described in the description. The drawings and detailed description are not intended to limit the scope of the application in any way.

[0029] First, the application background involved in the present application is explained:

[0030] With the large-scale application of lithium-ion batteries in new energy vehicles and energy storage systems, the safety problems caused by thermal runaway have attracted widespread attention, and higher requirements have been put forward for the energy density and safety of batteries. To solve these problems, solid-state batteries (especially all-solid-state batteries) have become a research hotspot because they use solid-state electrolytes instead of liquid electrolytes, have higher safety and potential high energy density.

[0031] All-solid-state batteries are attracting attention due to their high safety and high energy density, and the characteristic of solid-state electrolytes not burning and being difficult to decompose is one of the key advantages. Currently, the main solid-state electrolytes mainly include sulfide, oxide, polymer, and halide types. Sulfide solid-state electrolytes have ion conductivity comparable to liquid electrolytes, and also have the advantages of low synthesis temperature, good ductility, and tight interface contact, making them particularly suitable for high-energy-density energy storage devices and are recognized as one of the ideal materials for all-solid-state batteries.

[0032] According to the crystal structure type, sulfide electrolytes can be divided into three categories: glassy, glass-ceramic, and crystalline. Among them, crystalline electrolytes perform particularly well, with extremely high ionic conductivity. For example, Li 5.5 PS 4.5 Cl 1.5 (about 10 mS / cm), Li 10 GeP2S 12 (about 12 mS / cm), and Li 9.54 Si 1.74 P 1.44 S 11.7 Cl 0.3(about 25 mS / cm).

[0033] However, the air stability of the crystalline electrolyte is poor, and it is easy to react with moisture to release toxic H2S gas when exposed to air, and the electrochemical performance rapidly decays. Therefore, its preparation process needs to be carried out under strict environmental control, usually requiring the environmental dew point to be no higher than -70°C, which brings significant difficulties to its large-scale production.

[0034] Further, there are also sulfide electrolytes with good air stability, such as Li4SnS4 and Li3SbS4, but the conductivity of this part of the sulfide electrolyte is very low. Although the sulfide solid electrolyte with poor ionic conductivity usually has good chemical stability, its low ion migration ability will lead to increased internal resistance of the battery and decreased rate performance, which also limits its application in high-power or high-energy density all-solid-state batteries.

[0035] That is to say, the sulfide solid electrolyte currently faces a major challenge: there is a prominent contradiction between ionic conductivity and stability. Specifically, sulfide electrolytes with high ionic conductivity tend to have poor air stability, while materials with good stability have low ionic conductivity, which has no practical application value in all-solid-state batteries.

[0036] Therefore, how to maintain high ionic conductivity while ensuring high stability has become a key issue in the current research of sulfide electrolytes.

[0037] Based on the above technical problems, the technical concept of the present application is as follows: taking a sulfide electrolyte with good air stability (such as Li3SbS4) as the matrix, and introducing iodine (I) element and metal element (Me) for collaborative doping modification, thereby simultaneously improving the ionic conductivity and interface stability. Specifically, by doping I to provide additional lithium ion transmission channels, and by doping metal element Me to optimize the crystal lattice structure and stabilize the battery interface, thereby improving the conductivity. At the same time, LiI can also be formed at the battery interface by doping I, thereby inhibiting the growth of lithium dendrites and improving the interface stability of the electrolyte and lithium metal anode.

[0038] The technical solutions of the present application and how the technical solutions of the present application solve the above technical problems will be described in detail below with specific examples. The following specific examples can be combined with each other, and the same or similar concepts or processes can not be described again in some examples. The embodiments of the present application will be described below with reference to the accompanying drawings.

[0039] Figure 1 The flowchart of the preparation method of the glass-ceramic sulfide electrolyte provided by the present application is shown in FIG. 1, and the preparation method of the glass-ceramic sulfide electrolyte can be realized by the following steps. Figure 1 The flowchart of the preparation method of the glass-ceramic sulfide electrolyte provided by the present application is shown in FIG. 1, and the preparation method of the glass-ceramic sulfide electrolyte can be realized by the following steps.

[0040] S11. Under an inert atmosphere environment, weigh Li2S, Sb2S3, MeS, a , LiI, and S according to the molar ratio of (1.5 - 0.5x - y):0.5x:(1 - x):y:(2.5 - a + ax - x).

[0041] It should be understood that the raw materials for preparing the glass - ceramic sulfide electrolyte are explained as follows:

[0042] Li2S is an inorganic compound composed of lithium element (Li) and sulfur element (S). It usually appears as a yellow - to - brown powder, has strong hygroscopicity, and reacts violently with water to produce toxic hydrogen sulfide (H2S) gas.

[0043] Sb2S3 is a compound composed of antimony element (Sb) and sulfur element (S). It often exists in the form of orange - red or black crystalline powder and also exists as stibnite in nature.

[0044] MeS a does not specifically refer to a single substance but is a general formula representing a large class of metal sulfides. Here, Me is a general term for metal elements, and a represents the number of sulfur atoms combined with the metal.

[0045] Optionally, Me includes at least one of the following: W, Mn, Y, Cr, In, Bi, Sc, Zn, Cu, Ca, and Ba.

[0046] LiI is a white crystalline salt composed of lithium element (Li) and iodine element (I). It is extremely easy to absorb moisture in the air and deliquesce, and is soluble in water.

[0047] S is a non - metal element, commonly known as sulfur. It usually exists in the form of light - yellow brittle solids or powders. Sulfur is insoluble in water and has a special odor.

[0048] Among them, a is 1, 1.5, or 2.

[0049] It should be understood that the value of a is determined by the chemical valence of the Me element.

[0050] Exemplarily, MeSa can be specifically realized as: WS2 (a = 2), MnS (a = 1), Y2S3 (a = 1.5), Cr2S3 (a = 1.5), In2S3 (a = 1.5), Bi2S3 (a = 1.5), Sc2S3 (a = 1.5), ZnS (a = 1), CuS (a = 1), CaS (a = 1), and BaS (a = 1).

[0051] Among them, the value range of x is 0 < x < 1, and the value range of y is 0 < y < 1.

[0052] It should be understood that the values of x and y are determined by the chemical valence of the Li element, the Sb element, the M element, the S element, and the I element.

[0053] For example, when Me is Mn, x is 0.02 and y is 0.1; when Me is Cu, x is 0.02 and y is 0.3; and when Me is Ca, x is 0.6 and y is 0.1.

[0054] It should be understood that, in addition to the above examples, x and y can also have different values within their respective value ranges to meet the specific needs of users in specific application scenarios.

[0055] In a specific implementation, the value of x is in the range of 0.02≤x≤0.6, and / or the value of y is in the range of 0.1≤y≤0.5.

[0056] Further, the gas in the inert atmosphere is at least one of argon, nitrogen, and helium. It should be understood that the gas in the inert atmosphere is a gas that is very unreactive in chemical properties.

[0057] Since Li2S and LiI will undergo a violent hydrolysis reaction with water vapor in the air, not only will they deteriorate, but they will also produce highly toxic hydrogen sulfide (H2S) gas. At the same time, oxygen can also cause some components to be oxidized, thereby changing the stoichiometric ratio of the material and introducing impurities, which seriously affects the purity, structure, and ionic conductivity of the electrolyte in the subsequent synthesis process. Therefore, Li2S, Sb2S3, MeS a , LiI, and S are weighed under an inert atmosphere to ensure that the weighed Li2S, Sb2S3, MeS a , LiI, and S are not contaminated or deteriorated.

[0058] In a possible implementation, Li2S, Sb2S3, MeS a , LiI, and S can be weighed by a balance or other weighing tools.

[0059] S12, the weighed Li2S, Sb2S3, MeS a , LiI, and S are subjected to ball milling treatment to obtain an amorphous solid electrolyte powder precursor.

[0060] The ball milling treatment is a key technical means for crushing, mixing, and fine processing of solid materials through mechanical force.

[0061] In a possible implementation, Li2S, Sb2S3, MeS aLiI, S and grinding balls are loaded into a sealed ball mill tank, and the grinding balls and the materials (Li2S, Sb2S3, MeS a LiI and S) are subjected to strong collision, friction and shearing by high-speed rotation or vibration of the ball mill. The mechanical energy not only continuously reduces the particle size of the raw material powder to the nanometer or micrometer level, but also realizes uniform mixing and alloying between particles of different components, and makes the crystal structure amorphous.

[0062] In another possible implementation, the weighed Li2S, Sb2S3, MeS a LiI and S can be mixed by a mortar to obtain a precursor powder. Then the precursor powder is subjected to ball milling to obtain an amorphous solid electrolyte powder precursor.

[0063] The mortar can be an agate mortar or a mortar made of other materials, and the application does not specifically limit the material of the mortar.

[0064] Optionally, the mixing time is 20 minutes to 1 hour.

[0065] It should be understood that the mixing time refers to the duration of mixing Li2S, Sb2S3, MeS a LiI and S.

[0066] In this implementation, Li2S, Sb2S3, MeS a LiI and S are first manually ground to break up larger agglomerates, so that the distribution of each component is more uniform, and preliminary homogenization is achieved on a macroscopic scale, reducing the burden of subsequent ball milling, effectively shortening the ball milling time, reducing energy consumption, and reducing the introduction of impurities and equipment wear caused by excessive ball milling.

[0067] In the above implementation, "ball milling the precursor powder to obtain an amorphous solid electrolyte powder precursor" can be implemented as follows: the precursor powder is added to a ball mill tank for sealing treatment, and a planetary ball mill is used to ball mill the precursor powder to obtain an amorphous solid electrolyte powder precursor.

[0068] In any of the above embodiments, the ball milling speed is 100-800 rpm and / or the ball milling time is 2-30 h.

[0069] It should be understood that the ball milling time refers to the duration of the ball milling process.

[0070] In actual applications, this step can also be carried out in an inert atmosphere.

[0071] S13, sintering the amorphous solid electrolyte powder precursor under an inert atmosphere to obtain a glass-ceramic sulfide electrolyte.

[0072] The sintering treatment is a heat treatment of the amorphous solid electrolyte powder precursor obtained after ball milling under a high-temperature environment. The amorphous solid electrolyte powder precursor is heated at a temperature lower than its melting point, so that the contact points between the particles are combined and densified through atomic diffusion and surface energy reduction, and gradually grow into crystals with regular lattice structures. The sintering treatment not only eliminates the stress defects in the amorphous solid electrolyte powder precursor, but also promotes the formation and growth of specific high-ionic-conductivity crystal phases, thereby significantly improving the ion conductivity and overall density, and finally obtaining a glass-ceramic sulfide electrolyte with stable performance.

[0073] The sintering temperature of the sintering treatment is 200-500℃, and / or the sintering time is 1-20h.

[0074] In one possible implementation, the sintering treatment of the amorphous solid electrolyte powder precursor can be performed by a heat treatment furnace, a sintering furnace, a rotary kiln, or the like.

[0075] In actual applications, a sufficient amount of argon can be introduced into a sealed heat treatment furnace to completely remove air. The amorphous solid electrolyte powder precursor is placed in a crucible and placed in the heat treatment furnace. The sintering treatment is performed at the sintering temperature until the sintering time is reached.

[0076] It should be understood that the entire sintering treatment needs to be performed in an inert atmosphere to avoid reaction of the amorphous solid electrolyte powder precursor with other components in the air.

[0077] It should be understood that the chemical formula of the obtained glass-ceramic sulfide electrolyte is Li 3-x-y Sb x Me 1-x S 4-y I y .

[0078] The preparation method of the glass-ceramic sulfide electrolyte provided by the embodiments of the present application includes the following steps: (1) preparing a glass-ceramic sulfide electrolyte by mixing Li2S, Sb2S3, MeS, LiI, and S in a molar ratio of (1.5-0.5x-y):0.5x:(1-x):y:(2.5-a+ax-x) under an inert atmosphere, wherein x is 0.1-0.5, y is 0.1-0.5, and a is 0.1-0.5; and (2) sintering the amorphous solid electrolyte powder precursor obtained in the step (1) under an inert atmosphere to obtain a glass-ceramic sulfide electrolyte. a a ​Li2S, Sb2S3, MnS, LiI and S are ball milled to obtain amorphous solid electrolyte powder precursor. The amorphous solid electrolyte powder precursor is sintered under an inert atmosphere to obtain a glass-ceramic sulfide electrolyte. In the technical solution, on the basis of the existing glass-ceramic sulfide electrolyte (Li3SbS4 system), the high stability of the glass-ceramic sulfide electrolyte is retained, and the ion conductivity is improved by doping I elements and metal elements Me. At the same time, the doping of I elements can also improve the stability to lithium metal, meet the demand of improving the energy density of the all-solid-state battery, and the doping of metal elements Me stabilizes the battery interface and further improves the stability of the glass-ceramic sulfide electrolyte.

[0079] Further, the introduction of lithium halide (LiI) can also reduce the Young's modulus of the solid electrolyte. By further reducing the Young's modulus of the glass-ceramic sulfide electrolyte, the solid-solid interface contact between the active material and the solid electrolyte is maintained to prolong the cycle life of the solid-state battery, and the demand of low cycle pressure and low preparation pressure of the all-solid-state battery is met.

[0080] That is, the embodiments of the present application improve the ion conductivity by doping and modifying the sulfide electrolyte with good air stability, reduce the manufacturing cost of the all-solid-state battery, and are conducive to promoting the mass production of the all-solid-state battery.

[0081] Next, the technical effects of the present application will be illustrated by several examples and comparative examples.

[0082] Example 1

[0083] The chemical formula of the glass-ceramic sulfide electrolyte in Example 1 is Li 2.88 Sb 0.02 Mn 0.98 S 3.9 I 0.1 The corresponding preparation method is:

[0084] (1) In an argon-filled glove box, Li2S, Sb2S3, MnS, LiI and S are weighed according to the molar ratio of 1.39:0.01:0.98:0.1:1.5, and the weighed Li2S, Sb2S3, MnS, LiI and S are put into a mortar and mixed manually for 30 min to obtain a uniform precursor powder;

[0085] (2) The precursor powder is sealed in a ball milling tank, and a planetary ball mill is used to ball mill the precursor powder at a speed of 600 rpm for 24 h to obtain an amorphous solid electrolyte powder precursor;

[0086] (3), under inert atmosphere, the amorphous solid electrolyte powder precursor is put into a muffle furnace, and sintering is performed at a sintering temperature of 400°C for 10h to obtain a glass-ceramic sulfide electrolyte with a composition of Li 2.88 Sb 0.02 Mn 0.98 S 3.9 I 0.1 .

[0087] Example 2

[0088] Compared with Example 1, Example 2 changes the chemical formula of the glass-ceramic sulfide electrolyte, and the chemical formula of the glass-ceramic sulfide electrolyte in Example 2 is Li 2.68 Sb 0.02 Cu 0.98 S 3.7 I 0.3 .

[0089] In the corresponding preparation method, compared with Example 1, Example 2 changes the components and molar ratios of raw materials, that is, Li2S, Sb2S3, CuS, LiI and S need to be weighed according to the molar ratio of 1.19:0.01:0.98:0.3:1.5, and the process after weighing is the same as that of Example 1.

[0090] Example 3

[0091] Compared with Example 1, Example 3 changes the chemical formula of the glass-ceramic sulfide electrolyte, and the chemical formula of the glass-ceramic sulfide electrolyte in Example 3 is Li 2.3 Sb 0.6 Ca 0.4 S 3.9 I 0.1 .

[0092] In the corresponding preparation method, compared with Example 1, Example 3 changes the components and molar ratios of raw materials, that is, Li2S, Sb2S3, CaS, LiI and S need to be weighed according to the molar ratio of 1.1:0.3:0.4:0.1:1.5, and the process after weighing is the same as that of Example 1.

[0093] Example 4

[0094] Compared with Example 1, Example 4 changes the chemical formula of the glass-ceramic sulfide electrolyte, and the chemical formula of the glass-ceramic sulfide electrolyte in Example 4 is Li 1.9 Sb 0.6 In 0.4 S 3.5 I 0.5 .

[0095] In the corresponding preparation method, compared with Example 1, Example 4 changes the components and molar ratio of raw materials, i.e. Li2S, Sb2S3, In2S3, LiI, S need to be weighed according to the molar ratio of 0.7:0.3:0.4:0.5:1.3, and the process after weighing is the same as that of Example 1.

[0096] Example 5

[0097] Compared with Example 1, Example 5 changes the chemical formula of the glass-ceramic sulfide electrolyte, and the chemical formula of the glass-ceramic sulfide electrolyte in Example 5 is Li 2.98 Sb 0.01 Y 0.99 S 3.99 I 0.01 .

[0098] In the corresponding preparation method, compared with Example 1, Example 5 changes the components and molar ratio of raw materials, i.e. Li2S, Sb2S3, Y3S2, LiI, S need to be weighed according to the molar ratio of 1.485:0.005:0.99:0.01:1.005, and the process after weighing is the same as that of Example 1.

[0099] Example 6

[0100] Compared with Example 1, Example 6 changes the chemical formula of the glass-ceramic sulfide electrolyte, and the chemical formula of the glass-ceramic sulfide electrolyte in Example 6 is Li 1.62 Sb 0.48 Cr 0.52 S 3.1 I 0.9 .

[0101] In the corresponding preparation method, compared with Example 1, Example 6 changes the components and molar ratio of raw materials, i.e. Li2S, Sb2S3, Cr3S2, LiI, S need to be weighed according to the molar ratio of 0.36:0.24:0.52:0.9:1.24, and the process after weighing is the same as that of Example 1.

[0102] Example 7

[0103] The chemical formula of the glass-ceramic sulfide electrolyte in Example 7 is Li 2.09 Sb 0.01 W 0.99 S 3.1 I 0.9 , the corresponding preparation method is:

[0104] (1), in the glove box filled with argon, Li2S, Sb2S3, WS2, LiI, S were weighed according to the molar ratio of 0.595:0.005:0.99:0.9:0.51, and the weighed Li2S, Sb2S3, MnS, LiI and S were put into a mortar and mixed manually for 30 min to obtain a uniform precursor powder;

[0105] (2), the precursor powder was added to a ball mill tank for sealing treatment, and a planetary ball mill was used to ball mill the precursor powder at a speed of 700 rpm for 24 h to obtain an amorphous solid electrolyte powder precursor;

[0106] (3), under an inert atmosphere, the amorphous solid electrolyte powder precursor was placed in a muffle furnace, and sintered at a sintering temperature of 320℃ for 5h to obtain a glass-ceramic sulfide electrolyte with a composition of Li 2.09 Sb 0.01 W 0.99 S 3.1 I 0.9 .

[0107] Example 8

[0108] Compared with Example 7, Example 8 changes the chemical formula of the glass-ceramic sulfide electrolyte, and the chemical formula of the glass-ceramic sulfide electrolyte in Example 8 is Li 2.68 Sb 0.3 W 0.7 S 3.98 I 0.02 .

[0109] In the corresponding preparation method, compared with Example 7, Example 8 changes the components and molar ratio of the raw materials, that is, Li2S, Sb2S3, WS2, LiI, S need to be weighed according to the molar ratio of 1.33:0.15:0.7:0.02:0.8, and the process after weighing is the same as Example 7.

[0110] Example 9

[0111] Compared with Example 7, Example 9 changes the chemical formula of the glass-ceramic sulfide electrolyte, and the chemical formula of the glass-ceramic sulfide electrolyte in Example 9 is Li 1.9 Sb 0.6 W 0.4 S 3.5 I 0.5 .

[0112] In the corresponding preparation method, compared with Example 7, Example 9 changes the components and molar ratio of raw materials, i.e. Li2S, Sb2S3, WS2, LiI, S need to be weighed according to the molar ratio of 0.7:0.3:0.4:0.5:1.1, and the subsequent process is the same as that of Example 7.

[0113] Comparative Example 1

[0114] Compared with Example 1, Comparative Example 1 changes the chemical formula of the glass-ceramic sulfide electrolyte, and the chemical formula of the glass-ceramic sulfide electrolyte in Comparative Example 1 is Li3SbS4.

[0115] In the corresponding preparation method, compared with Example 1, Comparative Example 1 weighs Li2S, Sb2S3, S according to the molar ratio of 3:1:2, and the subsequent process is the same as that of Example 1.

[0116] Test Example

[0117] Ion conductivity test: 100 mg of glass-ceramic sulfide electrolyte powder was weighed and placed in a mold to press into a dense electrolyte sheet under a pressure of 360 MPa. Under the pressure maintaining condition, the impedance spectrum of the electrolyte sheet was tested at room temperature of 25°C using an electrochemical workstation by electrochemical impedance spectroscopy. The absolute value of the phase angle minimum frequency point was taken as the resistance (Resistance of the Solid Electrolyte, RSE). Based on the resistance value and combined with the geometric size of the electrolyte sheet, the ion conductivity was calculated by the formula σ=d / (R×A). Wherein, σ is the ion conductivity, d is the thickness of the electrolyte sheet, R is the resistance, and A is the contact area of the electrode and the electrolyte sheet.

[0118] Lithium metal stability test: 100 mg of glass-ceramic sulfide electrolyte powder was weighed and placed in a mold to press into a dense electrolyte sheet under a pressure of 360 MPa. Then, lithium sheets with a thickness of 50 um were placed on both sides of the electrolyte sheet to form a lithium symmetric battery. Then, the lithium symmetric battery was tested at a constant current of 0.1 mA / cm 2 under 0.1 V.

[0119] Battery test: In an argon glove box, glass-ceramic sulfide electrolyte and positive active material Li(Ni 0.8 Co 0.1 Mn 0.1)O2(NCM811) were weighed in a weight ratio of 20:80. They were ground uniformly using an agate mortar, thereby producing a composite cathode material. In an insulating outer cylinder with a diameter of 10 mm, 14 mg of the above composite cathode material, 70 mg of glass-ceramic sulfide electrolyte were stacked. It was pressure-formed at a pressure of 360 MPa, thereby obtaining a cathode and a solid electrolyte layer. Next, an aluminum foil was stacked on the cathode side, thereby forming a current collector on the cathode side. Then, on the side of the solid electrolyte layer opposite to the side in contact with the cathode, a lithium sheet with a thickness and diameter of 200 μm and 10 mm, respectively, was placed as an anode material. It was pressure-formed at a pressure of 80 MPa, thereby producing a stack composed of a cathode, a solid electrolyte layer, and an anode. Next, stainless steel current collectors were arranged above and below the stack, and current lead wires were attached to the stainless steel current collectors. The assembled solid-state battery was subjected to a cycle performance test. Among them, the test conditions were: current density was 1C, and voltage range was 2.7-4.3V (Li+ / Li).

[0120] Exemplarily, the ionic conductivities of each of the examples and the comparative example are shown in Table 1.

[0121] Table 1 ionic conductivities of each of the examples and the comparative example

[0122]

[0123]

[0124] As can be seen from Table 1, the ionic conductivities of Examples 1-9 are all greater than the ionic conductivity of Comparative Example 1.

[0125] Exemplarily, the lithium metal stability test results of each of the examples and the comparative example are shown in Table 2.

[0126] Table 2 lithium metal stability test results of each of the examples and the comparative example

[0127] Examples Molecular formula Cycle time h Example 1 Li 2.88 Sb 0.02 Mn 0.98 S 3.9 I 0.1 ]]> 663 Example 2 Li 2.68 Sb 0.02 Cu 0.98 S 3.7 I 0.3 ]]> 735 Example 3 Li 2.3 Sb 0.6 Ca 0.4 S 3.9 I 0.1 ]]> 843 Example 4 Li 1.9 Sb 0.6 In 0.4 S 3.5 I 0.5 ]]> 892 Example 5 Li 2.98 Sb 0.01 Y 0.99 S 3.99 I 0.01 ]]> 626 Example 6 Li 1.62 Sb 0.48 Cr 0.52 S 3.1 I 0.9 ]]> 869 Example 7 Li 2.09 Sb 0.01 W 0.99 S 3.1 I 0.9 ]]> 812 Example 8 Li 2.68 Sb 0.3 W 0.7 S 3.98 I 0.02 ]]> 578 Example 9 Li 1.9 Sb 0.6 W 0.4 S 3.5 I 0.5 ]]> 759 Comparative Example 1 Li3SbS4 562

[0128] Among them, the cycle time refers to the time during which the lithium symmetrical battery can stably work before short circuit or other failure modes occur in the constant current test of the battery. That is, the cycle time refers to the time during which the battery can stably work before short circuit or other failure modes occur.

[0129] As can be seen from Table 2, the cycle times of Examples 1-9 are all greater than the cycle time of Comparative Example 1. That is, the lithium metal stability of Examples 1-9 is higher than the lithium metal stability of Comparative Example 1.

[0130] Exemplarily, the battery test results of each of the examples and the comparative example are shown in Table 3.

[0131] Table 3 Battery test results of each example and comparative example

[0132]

[0133] Wherein, the Chinese full name of the initial efficiency is the first coulombic efficiency, which refers to the ratio of the discharge capacity to the charge capacity in the first charge-discharge cycle of the battery, i.e. initial efficiency = discharge capacity / charge capacity.

[0134] Wherein, the 100 cycle capacity retention rate refers to the retention degree of the discharge capacity of the battery relative to the first discharge capacity after 100 charge-discharge cycles, i.e. the ratio of the 100th discharge capacity to the first discharge capacity.

[0135] As can be seen from Table 3, the initial efficiency of Examples 1-9 is greater than that of Comparative Example 1, indicating that the irreversible lithium loss of Examples 1-9 is less than that of Comparative Example 1, and the higher the active material utilization rate of the battery, the longer the potential cycle life.

[0136] As can be seen from Table 3, the 100 cycle capacity retention rate of Examples 1-9 is greater than that of Comparative Example 1, indicating that the battery life of Examples 1-9 is longer and more stable.

[0137] The application also provides a solid-state battery, comprising a positive electrode, a negative electrode and a glass-ceramic sulfide electrolyte. The glass-ceramic sulfide electrolyte is the glass-ceramic sulfide electrolyte provided in any of the above glass-ceramic sulfide electrolyte embodiments, or is prepared by the preparation method of any of the above glass-ceramic sulfide electrolyte embodiments.

[0138] Finally, it should be noted that: other embodiments of the application will be readily apparent to those skilled in the art with the consideration of the specification and practice of the application disclosed herein. The application is intended to cover any variations, uses or adaptive changes of the application following the general principles of the application and including common knowledge or conventional technical means in the art which are not disclosed by the application, and is not limited to the precise structure described above and shown in the drawings, and various modifications and changes can be made without departing from the scope thereof. The scope of the application is only limited by the appended claims.

Claims

1. A glass-ceramic sulfide electrolyte, characterized in that, The glass-ceramic sulfide electrolyte has a general chemical formula Li 3-x-y Sb x Me 1-x S 4-y I y ; Wherein, the Me is a metal element, the value range of the x is 0 2. The glass-ceramic sulfide electrolyte according to claim 1, characterized in that, The Me includes at least one of W, Mn, Y, Cr, In, Bi, Sc, Zn, Cu, Ca and Ba.

3. The glass-ceramic sulfide electrolyte according to claim 1 or 2, characterized in that, The value range of the x is 0.02≤x≤0.6, and / or the value range of the y is 0.1≤y≤0.

5.

4. A method of preparing a glass-ceramic sulfide electrolyte, characterized in that, The preparation method is used for preparing the glass-ceramic sulfide electrolyte in any one of claims 1-3, and the preparation method comprises: Li2S, Sb2S3, MeS, LiI and S are weighed according to the molar ratio of (1.5-0.5x-y):0.5x:(1-x):y:(2.5-a+ax-x) under an inert atmosphere, wherein the value range of x is 0 a , the value range of y is 0 The weighed Li2S, Sb2S3, MeS a , Lil and S are subjected to ball milling to obtain an amorphous solid electrolyte powder precursor; The amorphous solid electrolyte powder precursor is subjected to a sintering treatment under the inert atmosphere to obtain the glass-ceramic sulfide electrolyte.

5. The preparation method according to claim 4, characterized in that, The ball milling speed of the ball milling treatment is 100-800 rpm and / or the ball milling time is 2-30 h.

6. The production method according to claim 4 or 5, characterized by, The sintering temperature of the sintering treatment is 200-500 ℃ and / or the sintering time is 1-20 h.

7. The production method according to claim 4 or 5, characterized by, The weighed Li2S, Sb2S3, MeS a LiI and S are subjected to ball milling to obtain an amorphous solid electrolyte powder precursor, comprising: The weighed Li2S, Sb2S3, MeS a , Lil and S are mixed by a mortar to obtain a precursor powder; The precursor powder is subjected to a ball milling treatment to obtain the amorphous solid electrolyte powder precursor.

8. The preparation method according to claim 7, characterized in that, The ball milling treatment of the precursor powder to obtain the amorphous solid electrolyte powder precursor comprises: The precursor powder is sealed in a ball milling tank and subjected to a ball milling treatment by a planetary ball mill to obtain the amorphous solid electrolyte powder precursor.

9. The method of claim 4, 5, or 8, wherein, The gas in the inert atmosphere is at least one of argon, nitrogen and helium.

10. A solid state battery, characterized by Comprise: A positive electrode, a negative electrode and a glass-ceramic sulfide electrolyte; The glass-ceramic sulfide electrolyte is the glass-ceramic sulfide electrolyte in any one of claims 1-3, or is prepared by the preparation method in any one of claims 4-9.

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