Sulfide solid electrolyte and its preparation method, all-solid-state lithium-ion battery and electronic device

Abstract

By providing a sulfide solid electrolyte, a method for preparing the same, an all-solid-state lithium-ion battery, and electronic equipment, the stability of the conductivity of the sulfide solid electrolyte is improved, atmospheric stability is enhanced, the properties of the electrolyte / active material interface are improved, and the lifespan and safety of the lithium battery in the all-solid-state lithium-ion battery are improved. [Solution] The present invention provides a sulfide solid electrolyte and a method for preparing the same, an all-solid-state lithium-ion battery, and an electronic device. The chemical formula of the sulfide solid electrolyte is Li a P 1-b M b S c O d X e And here, 5

Description

[Technical Field]

[0001] The present invention relates to the technology of lithium-ion batteries, and more specifically to sulfide solid electrolytes, methods for preparing them, and their applications.

[0002] This application claims partial priority to the Chinese patent application filed on October 11, 2024, application number 202411418926.2, titled "Sulfide Solid Electrolyte, Method for Preparation Thereof, and Applications," and also claims priority to the Chinese patent application filed on October 31, 2024, application number 202411545093.6, titled "Sulfide Solid Electrolyte, Method for Preparation Thereof, and Applications," with the relevant content incorporated into this invention by reference. [Background technology]

[0003] Lithium-ion batteries are widely used in fields such as portable electronic devices, electric vehicles, and energy storage systems due to their advantages such as high energy density, high power density, and long cycle life. However, conventional lithium-ion batteries use flammable organic liquid electrolytes, which poses safety problems and limits their further development. To overcome the safety problems of organic liquid electrolytes, solid-state lithium batteries have attracted considerable attention in recent years. Solid-state lithium batteries use a solid electrolyte instead of conventional organic liquid electrolytes, offering advantages such as higher safety, a wider electrochemical window, and a longer cycle life.

[0004] Currently, sulfide solid electrolytes are widely used in lithium-ion batteries. However, many existing sulfide electrolytes have complex preparation methods, are expensive, and the manufactured sulfide solid electrolytes are highly hygroscopic and unstable in the atmosphere. Furthermore, there is a need for further improvement in the electrochemical performance, particularly cycle life, of existing sulfide electrolytes in lithium-ion batteries. [Overview of the project] [Problems that the invention aims to solve]

[0005] The present invention provides a sulfide solid electrolyte, a preparation method thereof, and an application. By the sulfide solid electrolyte, the preparation method thereof, and the application of the present invention, the stability of the conductivity of the sulfide solid electrolyte can be improved, the air stability can be enhanced, the interfacial properties of the electrolyte / active material can be improved, and the life and safety of the lithium battery of the all-solid-state lithium-ion battery can be improved.

Means for Solving the Problems

[0006] To solve the above technical problems, the present invention provides a sulfide solid electrolyte. The chemical formula of the sulfide solid electrolyte is Li a P 1-b M b S c O d X e where 5 < a < 6, 0 < b < 1, 1.5 < c < 5, 0 < d < 2.5, 4 < c + d < 5, and 1 < e < 2. M is one or more selected from Al, Ga, In, Ti, Sc, As, Sb, Bi, V, or Nb. X is one or more selected from Cl, Br, or I.

[0007] In one embodiment of the present invention, M is one or more selected from Sb, In, or Bi.

[0008] In one embodiment of the present invention, X is Cl. The allowable range of b is 0 < b ≤ 0.1.

[0009] Further, the present invention provides a preparation method of the above sulfide solid electrolyte. The method includes the following. Based on the chemical formula of the sulfide solid electrolyte, a Li source, a P source, an M source, an S source, and an X source are mixed according to stoichiometry, and then put into a ball mill pot for ball milling to obtain a sulfide solid electrolyte precursor powder. The sulfide solid electrolyte precursor powder is calcined at a predetermined temperature to obtain the sulfide solid electrolyte.

[0010] In one embodiment of the present invention, the Li source is one or more selected from LiCl, LiBr, LiI, or Li₂S; the P source is one or more selected from elemental P, P₂S₅, P₄S₆, PCl₅, or PBr₅; the M source is one or more selected from oxides of M or sulfides of M; the S source is one or more selected from elemental S, Li₂S, P₂S₅, P₄S₆, As₂S₅, As₂S₃, Sb₂S₅, Sb₂S₃, Bi₂S₅, Bi₂S₃, Al₂S₃, Ga₂S₃, In₂S₃, or Sc₂S₃; the X source is one or more selected from LiCl, PCl₅, LiBr, PBr₅, LiI, or I₂; and the O element in the chemical formula is derived from the oxide of M.

[0011] In one embodiment of the present invention, the ball milling time is 1 to 48 hours, the ball mill rotation speed is 50 to 1500 rpm, and the ratio of balls to raw materials is 1:1 to 100:1.

[0012] In one embodiment of the present invention, the predetermined temperature is 400 to 600 °C, and the firing time is 1 to 18 hours.

[0013] Furthermore, the present invention provides an all-solid-state lithium-ion battery. The battery includes at least the following. Li 2.35 Zr 0.65 Fe 0.35 Cl₅Br 0.5 I 0.5 a positive electrode sheet including a halide solid electrolyte containing the above, a negative electrode sheet, and a solid electrolyte membrane disposed between the adjacent positive electrode sheet and the negative electrode sheet and containing the above sulfide solid electrolyte.

[0014] In one embodiment of the present invention, the positive electrode sheet includes a positive electrode active material, and the positive electrode active material is one or more selected from lithium nickel cobalt manganese oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel manganese oxide, lithium cobalt oxide, or lithium nickel cobalt aluminum oxide.

[0015] Furthermore, the present invention provides an electronic device that includes the above-described all-solid-state lithium-ion battery. [Effects of the Invention]

[0016] As described above, the present invention provides a sulfide solid electrolyte, a method for preparing the same, and its applications. By introducing +3 or +5 valence M and O elements into the sulfide solid electrolyte, the present invention enables the formation of alloys such as LiCl, Li2O, and Li-Sb / Li-Bi / Li-In at the electrolyte / lithium metal anode interface layer, thereby homogenizing the electric field and equipping the local current density. This regulates Li nucleation and growth and effectively suppresses the rapid growth of lithium dendritic crystals at the growth interface. Therefore, the stability and performance of lithium-ion batteries can be significantly improved, and the lifespan and safety of lithium batteries in all-solid-state lithium-ion batteries can be enhanced. This improves the intrinsic resistance of the sulfide solid electrolyte to atmospheric degradation, effectively reduces H2S generation, increases the battery's potential in actual production, and thereby enhances the atmospheric and chemical stability of the sulfide solid electrolyte. This enables the sulfide solid electrolyte to have relatively high stability and specific reactivity, improves the conductivity stability of the sulfide solid electrolyte, enhances atmospheric stability, and improves the electrolyte / active material interface properties, thereby improving compatibility with the active material. This method can improve the ionic conductivity and electrochemical stability of sulfide solid electrolytes, thereby improving voltage stability. [Brief explanation of the drawing]

[0017] To more clearly explain the technical solutions of the embodiments of the present invention, the accompanying drawings necessary for describing the embodiments are briefly introduced below. Clearly, the accompanying drawings in the following description represent only a few embodiments of the present invention, and those skilled in the art can obtain other accompanying drawings based on these without requiring any creative work.

[0018] [Figure 1] This figure shows the long-term cycle performance of the all-solid-state lithium-ion battery of Example 3 at room temperature (1C / 1C). [Figure 2] This is an SEM image of the sulfide solid electrolyte of Example 3. [Modes for carrying out the invention]

[0019] The following describes embodiments of the present invention by specific examples, and those skilled in the art will readily understand other advantages and effects of the present invention from the contents disclosed herein. The present invention can also be implemented or applied in other different specific embodiments, and the details of each item herein can also be modified or changed in various ways based on different perspectives and applications without departing from the spirit of the invention.

[0020] It should be understood that the present invention can be carried out in different forms and should not be construed as being limited to the embodiments provided herein. Rather, these embodiments are provided to make the disclosure thorough and complete and to fully communicate the scope of the invention to those skilled in the art.

[0021] The technical solutions of the present invention will be described in more detail below in combination with several embodiments. Clearly, the embodiments described are only a subset of the present invention, not all embodiments. All other embodiments that can be obtained by those skilled in the art without creative work based on the embodiments of the present invention are within the scope of the protection of the present invention.

[0022] This invention provides a sulfide solid electrolyte. The chemical formula of the sulfide solid electrolyte is Li a P 1-b M b S c O d X eThat is, 5 < a < 6, 0 < b < 1, 1.5 < c < 5, 0 < d < 2.5, 4 < c + d < 5, and 1 < e < 2. M is one or more selected from, for example, Al, Ga, In, Ti, Sc, Sb, Bi, As, V, or Nb, etc., and X is one or more selected from, for example, Cl, Br, or I. Here, by introducing the M element and the O element into the high-halogen-containing element sulfide solid electrolyte, P - O bonds and M - S bonds are formed in the crystal structure. Thereby, the inherent resistance to atmospheric deterioration is improved, the generation of H2S is effectively reduced, and the atmospheric stability and chemical stability of the sulfide solid electrolyte are enhanced. Further, when assembling an all-solid-state lithium-ion battery using the sulfide solid electrolyte, at the interface layer of the electrolyte / lithium metal negative electrode, alloys such as LiCl, Li2O, and Li - Sb / Li - Bi / Li - In, etc. can be formed. Here, Li2O has a relatively high intrinsic ionic conductivity, and alloys such as Li - Sb / Li - Bi / Li - In, etc. promote the high-speed diffusion mechanism of Li + ions, homogenize the electric field, and balance the local current density to regulate the nucleation and growth of Li. Further, LiCl has a relatively high interfacial energy and can effectively suppress the rapid growth of lithium dendrites at the growth interface, significantly improving the stability and performance of the lithium-ion battery and enhancing the life and safety of the lithium battery of the all-solid-state lithium-ion battery.

[0023] In one embodiment of the present invention, M is one or more selected from, for example, Sb, In, or Bi. The ionic radii of Sb, In, or Bi are appropriate, and the ionic radii of these elements are close to the radii of ions of the main elements in the sulfide electrolyte, such as sulfur and phosphorus. Therefore, during doping, these elements can more easily replace the positions of the main elements without causing excessive lattice strain. And the electronegativity of Sb, In, or Bi is appropriate, and it can form a stable chemical bond with the sulfur element in the sulfide, and is not easily destroyed by external influences. Therefore, relatively high stability and specific reactivity are imparted to the sulfide solid electrolyte. Thereby, the stability of the conductivity of the sulfide solid electrolyte can be improved, the air stability can be enhanced, the electrolyte / active material interfacial properties can be improved, and the compatibility with the active material can be improved.

[0024] In one embodiment of the present invention, X selects a halogen element. And depending on the difference in the halogen element, the anion disorder degree between the 4a site and the 4c site in the crystal structure of the sulfide solid electrolyte is different. It changes from a small amount of antisite defects when X is I to 60% site disorder when X is Cl, and the lithium conductivity of these compounds mainly depends on the disorder degree of anion site and cation site occupancy. Therefore, by selecting, for example, Cl as X, the ionic conductivity and electrochemical stability of the sulfide solid electrolyte are improved, and the voltage stability is improved. The allowable range of b is 0 < b ≤ 0.1. In one specific embodiment of the present invention, when M is +5 valent, b is most preferably 0.04, and when M is +3 valent, b is most preferably 0.02, which can improve the cycle performance of the lithium-ion battery.

[0025] The present invention also provides a method for preparing a sulfide solid electrolyte. The method includes at least the following. Based on the chemical formula of the sulfide solid electrolyte, after mixing the Li source, P source, M source, S source, and X source according to stoichiometry, put them into a ball mill pot and perform ball mill pulverization to obtain a sulfide solid electrolyte precursor powder. The sulfide solid electrolyte precursor powder is calcined at a predetermined temperature to obtain the sulfide solid electrolyte.

[0026] In one embodiment of the present invention, the sulfide solid electrolyte has the chemical formula Li a P 1-b M b S c O d X e Based on this, the Li source, P source, M source, S source and X source are uniformly mixed according to stoichiometry. Here, the Li source is one or more selected from LiCl, LiBr, LiI, or Li2S, etc., the P source is one or more selected from elemental P, P2S5, P4S6, PCl5, or PBr5, etc., the M source is one or more selected from oxides of M or sulfides of M, the S source is one or more selected from elemental S, Li2S, P2S5, P4S6, As2S5, As2S3, Sb2S5, Sb2S3, Bi2S5, Bi2S3, Al2S3, Ga2S3, In2S3, or Sc2S3, etc., and the X source is one or more selected from LiCl, PCl5, LiBr, PBr5, LiI, or I2, etc. The element O in the chemical formula is derived from an oxide of M. After uniformly mixing the raw materials, they are placed in a ball mill pot and ball mill grinding is performed under an inert atmosphere. Here, the ratio of balls to raw materials is, for example, 1:1 to 100:1, the ball mill rotation speed is, for example, 50 to 1500 rpm, and the ball mill grinding time is, for example, 1 to 48 hours, to obtain sulfide solid electrolyte precursor powder.

[0027] In one embodiment of the present invention, a sulfide solid electrolyte precursor powder is subjected to calcination treatment at a predetermined temperature. Here, the predetermined temperature is 400 to 600°C, and the calcination treatment time is 1 to 18 hours to obtain a sulfide solid electrolyte.

[0028] Furthermore, the present invention provides an all-solid-state lithium-ion battery comprising a positive electrode sheet, a negative electrode sheet, and a solid electrolyte film. The solid electrolyte film is placed between adjacent positive electrode sheets and negative electrode sheets. Here, the positive electrode sheet comprises a positive electrode active material and a halide solid electrolyte, the positive electrode active material being one or more selected from, for example, lithium nickel cobalt manganese oxide (NCM), lithium nickel oxide (LNO), lithium manganese oxide (LMO), lithium nickel manganese oxide (LNMO), lithium cobalt oxide (LCO), or lithium nickel cobalt aluminum oxide (NCA). The halide solid electrolyte is Li 2.35 Zr 0.65 Fe 0.35 Cl5Br 0.5 I 0.5 The halogen solid electrolyte contains a material that does not cause an exothermic reaction with the lithium-ion cathode active material, thereby improving the safety of the lithium-ion battery. The negative electrode sheet is one or more of the following: metallic lithium pieces, metallic indium pieces, or lithium indium alloy pieces. The negative electrode sheet also contains a negative electrode active material, which is one or more of the following selected from graphite-based materials, silicon materials, or composite materials of graphite-based and silicon materials. The solid electrolyte film contains the above-mentioned sulfide solid electrolyte, improving the performance of the all-solid-state lithium-ion battery.

[0029] In one embodiment of the present invention, the positive electrode sheet further comprises a conductive agent and a binder. Here, the conductive agent is one or at least two of the following: conductive carbon black (Super P, SP), carbon nanotube (CNT), vapor-grown carbon fiber (VGCF), or graphene. The binder is, for example, polytetrafluoroethylene (PTFE) and its derivatives. The mass ratio of the positive electrode active material, halogen solid electrolyte, conductive agent, and binder is, for example, (65-78):(20-30):(1-3):(1-2). In this embodiment, the mass ratio of the positive electrode active material, halogen solid electrolyte, conductive agent, and binder is, for example, 69:29:1:1, and the conductive agent is a combination of conductive carbon black (super-P) and vapor-grown carbon fiber (VGCF), with a mass ratio of conductive carbon black to vapor-grown carbon fiber of 1:1, and the binder is, for example, polytetrafluoroethylene. After uniformly mixing the positive electrode active material, halogen solid electrolyte, conductive agent, and binder, a mixed powder is obtained, and the mixed powder is dry-pressed to obtain a positive electrode sheet. In one embodiment of the present invention, when the negative electrode sheet contains the negative electrode active material, the negative electrode sheet further contains a solid electrolyte, conductive agent, and binder, etc., where the solid electrolyte is, for example, a halogen solid electrolyte or a sulfide electrolyte, and the present invention does not make any specific limitations. The binder is, for example, at least one of polyisoprene, polyethylene or polypropylene, and the conductive agent is, for example, at least one of carbon nanotubes, carbon fibers or acetylene black. The present invention does not limit the ratio of the negative electrode active material, conductive agent, and binder, and allows selection based on manufacturing requirements, and the negative electrode sheet is obtained, for example, by dry pressing.

[0030] In one embodiment of the present invention, in order to measure the performance of the obtained sulfide solid electrolyte, a solid electrolyte film is obtained by cold pressing the sulfide solid electrolyte under a predetermined pressure. Here, the predetermined pressure is, for example, 300 to 400 MPa, and the thickness of the solid electrolyte film is, for example, 100 to 500 μm.

[0031] In one embodiment of the present invention, a negative electrode sheet is selected, for example, from a metallic lithium piece. The positive electrode sheet, solid electrolyte film, and negative electrode sheet are sequentially added, pressurized, and sealed under vacuum or an inert atmosphere to obtain an all-solid-state lithium-ion battery. Here, the assembly process of the all-solid-state lithium-ion battery is completed, for example, in a glove box under an argon atmosphere.

[0032] The present invention will be described more specifically below by reference to examples, but these examples should not be understood as limiting. Appropriate modifications can be made within the scope consistent with the spirit of the present invention, and all such modifications fall within the technical scope of the present invention.

[0033] Example 1 Preparation of sulfide solid electrolytes: Under an argon atmosphere, 2 moles of Li2S, 1.5 moles of LiCl, 0.495 moles of P2S5, and 0.005 moles of Sb2O5 were placed in a tungsten steel ball mill pot. The mixture was added to the tungsten steel balls in a ball-to-raw material ratio of 40:1, and the ball mill was ground at 100 rpm for 10 minutes, then ground at 500 rpm for 16 hours to obtain a homogeneous sulfide solid electrolyte precursor powder. The sulfide solid electrolyte precursor powder was placed in a crucible and sintered at 500°C for 10 hours, and after cooling, Li 5.5 P 0.99 S 0.01 S 4.475 O 0.025 Cl 1.5 I obtained it. Preparation of electrolyte membranes: 50mg Li 5.5 P 0.99 S 0.01 S 4.475 O 0.025 Cl 1.5 An electrolyte membrane was prepared by cold pressing at 360 MPa, with a thickness of 400 μm and a diameter of 10 mm. Preparation of the positive electrode sheet: LiRing 0.8 Co 0.1 Mn0.1 O2, conductive agent, Li 2.35 Zr 0.65 Fe 0.35 Cl5Br 0.5 I 0.5 A positive electrode sheet was manufactured by mixing PTFE and PG in a mass ratio of 69:1:29:1 and using a dry press. The conductive agents were super-P and VGCF in a mass ratio of 1:1. Furthermore, the positive electrode sheet was cut into a 10 mm diameter disc. Negative electrode sheet: For the negative electrode sheet, a piece of metallic lithium was selected and cut into a 10mm diameter disc. Assembly of all-solid-state batteries: The positive electrode sheet, electrolyte membrane, and negative electrode sheet prepared as described above were assembled to form an all-solid-state battery. Assembling symmetric cells: Counter electrodes (Li) were placed on both sides of the electrolyte membrane and assembled to form a Li / Li symmetric cell.

[0034] Example 2 The chemical formula of the sulfide solid electrolyte prepared using 2 moles of Li2S, 1.5 moles of LiCl, 0.49 moles of P2S5, and 0.01 moles of Sb2O5 is Li 5.5 P 0.98 S 0.02 S 4.45 O 0.05 Cl 1.5 The other operations are the same as in Example 1.

[0035] Example 3 The chemical formula of the sulfide solid electrolyte prepared using 2 moles of Li2S, 1.5 moles of LiCl, 0.48 moles of P2S5, and 0.02 moles of Sb2O5 is Li 5.5 P 0.96 S 0.04 S 4.40 O 0.10 Cl 1.5 The other operations are the same as in Example 1.

[0036] Example 4 The chemical formula of the sulfide solid electrolyte prepared using 2 moles of Li2S, 1.5 moles of LiCl, 0.47 moles of P2S5, and 0.03 moles of Sb2O5 is Li 5.5 P 0.94 S 0.06 S 4.35 O 0.15 Cl 1.5 The other operations are the same as in Example 1.

[0037] Example 5 A sulfide solid electrolyte prepared using 2 moles of Li2S, 1.5 moles of LiCl, 0.46 moles of P2S5, and 0.04 moles of Sb2O5 is Li 5.5 P 0.92 S 0.08 S 4.3 O 0.20 Cl 1.5 The other operations are the same as in Example 1.

[0038] Example 6 The chemical formula of the sulfide solid electrolyte prepared using 2 moles of Li2S, 1.5 moles of LiCl, 0.45 moles of P2S5, and 0.05 moles of Sb2O5 is Li 5.5 P 0.9 S 0.1 S 4.25 O 0.25 Cl 1.5 The other operations are the same as in Example 1.

[0039] Example 7 The chemical formula of the sulfide solid electrolyte prepared using 1.6 mol Li2S, 1.9 mol LiCl, 0.48 mol P2S5, and 0.02 mol Sb2O5 is Li 5.1 P 0.96 S 0.04 S4O 0.10 Cl 1.9 The other operations are the same as in Example 1.

[0040] Example 8 The chemical formula of the sulfide solid electrolyte prepared using 2.4 moles of Li2S, 1.1 moles of LiCl, 0.48 moles of P2S5, and 0.02 moles of Sb2O5 is Li 5.9P 0.96 Sb 0.04 S 4.8 O 0.10 Cl 1.1 and other operations are the same as in Example 1.

[0041] Example 9 The chemical formula of the sulfide solid electrolyte prepared using 2 mol of Li2S, 1.4 mol of LiCl, 0.1 mol of LiBr, 0.48 mol of P2S5, and 0.02 mol of Sb2O5 is Li 5.5 P 0.96 Sb 0.04 S 4.40 O 0.10 Cl 1.4 Br 0.1 and other operations are the same as in Example 1.

[0042] Example 10 [[ID=3�]] The chemical formula of the sulfide solid electrolyte prepared using 2 mol of Li2S, 1.3 mol of LiCl, 0.1 mol of LiBr, 0.1 mol of LiI, 0.48 mol of P2S5, and 0.02 mol of Sb2O5 is Li 5.5 P 0.96 Sb 0.04 S 4.40 O 0.10 Cl 1.3 Br 0.1 I 0.1 and other operations are the same as in Example 1.

[0043] Example 11 The chemical formula of the sulfide solid electrolyte prepared using 2.01 mol of Li2S, 1.5 mol of LiCl, 0.495 mol of P2S5, and 0.005 mol of In2O3 is Li 5.52 P 0.99 In 0.01 S<​​​​​​​​​​The chemical formula of the sulfide solid electrolyte prepared using 2.015 moles of Li2S, 1.5 moles of LiCl, 0.4925 moles of P2S5, and 0.075 moles of In2O3 is Li 5.53 P 0.985 In 0.015 S 4.4775 O 0.0225 Cl 1.5 The other operations are the same as in Example 1.

[0045] Example 13 The chemical formula of the sulfide solid electrolyte prepared using 2.02 moles of Li2S, 1.5 moles of LiCl, 0.49 moles of P2S5, and 0.01 moles of In2O3 is Li 5.54 P 0.98 In 0.02 S 4.47 O 0.03 Cl 1.5 The other operations are the same as in Example 1.

[0046] Example 14 The chemical formula of the sulfide solid electrolyte prepared using 2.04 moles of Li2S, 1.5 moles of LiCl, 0.48 moles of P2S5, and 0.02 moles of In2O3 is Li 5.58 P 0.96 In 0.04 S 4.44 O 0.06 Cl 1.5 The other operations are the same as in Example 1.

[0047] Example 15 The chemical formula of the sulfide solid electrolyte prepared using 2.06 moles of Li2S, 1.5 moles of LiCl, 0.47 moles of P2S5, and 0.03 moles of In2O3 is Li 5.62 P 0.94 In 0.06 S 4.41 O 0.09 Cl 1.5 The other operations are the same as in Example 1.

[0048] Example 16 The chemical formula of the sulfide solid electrolyte prepared using 2.08 moles of Li2S, 1.5 moles of LiCl, 0.46 moles of P2S5, and 0.04 moles of In2O3 is Li 5.66 P 0.92 In 0.08 S 4.38 O 0.12 Cl 1.5 The other operations are the same as in Example 1.

[0049] Example 17 The difference between this example and Example 1 is that the chemical formula of the sulfide solid electrolyte prepared using 2.1 moles of Li2S, 1.5 moles of LiCl, 0.45 moles of P2S5, and 0.05 moles of In2O3 is Li 5.7 P 0.9 In 0.1 S 4.35 O 0.15 Cl 1.5 The key point is that the other operations are the same as in Example 1.

[0050] Example 18 The chemical formula of the sulfide solid electrolyte prepared using 1.62 moles of Li2S, 1.9 moles of LiCl, 0.49 moles of P2S5, and 0.01 moles of In2O3 is Li 5.14 P 0.98 In 0.02 S 4.07 O 0.03 Cl 1.9 The other operations are the same as in Example 1.

[0051] Example 19 The chemical formula of the sulfide solid electrolyte prepared using 2.42 moles of Li2S, 1.1 moles of LiCl, 0.49 moles of P2S5, and 0.01 moles of In2O3 is Li 5.94 P 0.98 In 0.02 S 4.87 O 0.03 Cl 1.1 The other operations are the same as in Example 1.

[0052] Example 20 The chemical formula of the sulfide solid electrolyte prepared using 2.02 moles of Li2S, 1.4 moles of LiCl, 0.1 moles of LiBr, 0.49 moles of P2S5, and 0.01 moles of In2O3 is Li 5.54 P 0.98 In 0.02 S 4.47 O 0.03 Cl 1.4 Br 0.1 The other operations are the same as in Example 1.

[0053] Example 21 The chemical formula of the sulfide solid electrolyte prepared using 2.02 mol Li2S, 1.3 mol LiCl, 0.1 mol LiBr, 0.1 mol LiI, 0.49 mol P2S5, and 0.01 mol In2O3 is Li 5.54 P 0.98 In 0.02 S 4.47 O 0.03 Cl 1.3 Br 0.1 I 0.1 The other operations are the same as in Example 1.

[0054] Example 22 The chemical formula of the sulfide solid electrolyte prepared using 2.01 moles of Li2S, 1.5 moles of LiCl, 0.495 moles of P2S5, and 0.005 moles of Bi2O3 is Li 5.52 P 0.99 Bi 0.01 S 4.485 O 0.015 Cl 1.5 The other operations are the same as in Example 1.

[0055] Example 23 The chemical formula of the sulfide solid electrolyte prepared using 2.015 moles of Li2S, 1.5 moles of LiCl, 0.4925 moles of P2S5, and 0.075 moles of Bi2O3 is Li 5.53 P 0.985 Bi 0.015 S 4.4775 O 0.0225 Cl 1.5 The other operations are the same as in Example 1.

[0056] Example 24 The chemical formula of the sulfide solid electrolyte prepared using 2.02 moles of Li2S, 1.5 moles of LiCl, 0.49 moles of P2S5, and 0.01 moles of Bi2O3 is Li 5.54 P 0.98 Bi 0.02 S 4.47 O 0.03 Cl 1.5 The other operations are the same as in Example 1.

[0057] Example 25 The chemical formula of the sulfide solid electrolyte prepared using 2.04 moles of Li2S, 1.5 moles of LiCl, 0.48 moles of P2S5, and 0.02 moles of Bi2O3 is Li 5.58 P 0.96 Bi 0.04 S 4.44 O 0.06 Cl 1.5 The other operations are the same as in Example 1.

[0058] Example 26 The chemical formula of the sulfide solid electrolyte prepared using 2.06 moles of Li2S, 1.5 moles of LiCl, 0.47 moles of P2S5, and 0.03 moles of Bi2O3 is Li 5.62 P 0.94 Bi 0.06 S 4.41 O 0.09 Cl 1.5 The other operations are the same as in Example 1.

[0059] Example 27 The chemical formula of the sulfide solid electrolyte prepared using 2.08 moles of Li2S, 1.5 moles of LiCl, 0.46 moles of P2S5, and 0.04 moles of Bi2O3 is Li 5.66 P 0.92 Bi 0.08 S 4.38 O 0.12 Cl 1.5 The other operations are the same as in Example 1.

[0060] Example 28 The chemical formula of the sulfide solid electrolyte prepared using 2.1 moles of Li2S, 1.5 moles of LiCl, 0.45 moles of P2S5, and 0.05 moles of Bi2O3 is Li 5.7 P 0.9 Bi 0.1 S 4.35 O 0.15 Cl 1.5 The other operations are the same as in Example 1.

[0061] Example 29 The chemical formula of the sulfide solid electrolyte prepared using 1.62 moles of Li2S, 1.9 moles of LiCl, 0.49 moles of P2S5, and 0.01 moles of Bi2O3 is Li 5.14 P 0.98 Bi 0.02 S 4.07 O 0.03 Cl 1.9 The other operations are the same as in Example 1.

[0062] Example 30 The chemical formula of the sulfide solid electrolyte prepared using 2.42 moles of Li2S, 1.1 moles of LiCl, 0.49 moles of P2S5, and 0.01 moles of Bi2O3 is Li 5.94 P 0.98 Bi 0.02 S 4.87 O 0.03 Cl 1.1 The other operations are the same as in Example 1.

[0063] Example 31 The chemical formula of the sulfide solid electrolyte prepared using 2.02 moles of Li2S, 1.4 moles of LiCl, 0.1 moles of LiBr, 0.49 moles of P2S5, and 0.01 moles of Bi2O3 is Li 5.54 P 0.98 Bi 0.02 S 4.47 O 0.03 Cl 1.4 Br 0.1 The other operations are the same as in Example 1.

[0064] Example 32 The chemical formula of the sulfide solid electrolyte prepared using 2.02 moles of Li2S, 1.3 moles of LiCl, 0.1 moles of LiBr, 0.1 moles of LiI, 0.49 moles of P2S5, and 0.01 moles of Bi2O3 is Li 5.54 P 0.98 Bi 0.02 S 4.47 O 0.03 Cl 1.3 Br 0.1 I 0.1 The other operations are the same as in Example 1.

[0065] Comparative Example 1 The chemical formula of the sulfide solid electrolyte prepared using 2 moles of Li2S, 1.5 moles of LiCl, and 0.5 moles of P2S5 is Li 5.5 PS 4.5 Cl 1.5 The other operations are the same as in Example 1.

[0066] Comparative Example 2 The chemical formula of the sulfide solid electrolyte prepared using 2 moles of Li2S, 1.4 moles of LiCl, 0.1 moles of LiBr, and 0.5 moles of P2S5 is Li 5.5 PS 4.5 Cl 1.4 Br 0.1 The other operations are the same as in Example 1.

[0067] Comparative Example 3 The chemical formula of the electrolyte prepared using 2 moles of Li2S, 1.3 moles of LiCl, 0.1 moles of LiBr, 0.1 moles of LiI, and 0.5 moles of P2S5 is Li 5.5 PS 4.5 Cl 1.3 Br 0.1 I 0.1 The other operations are the same as in Example 1.

[0068] Examples 1 to 32 and Comparative Examples 1 to 3 of the present invention employed different sulfide solid electrolytes, and the ionic conductivity of the sulfide solid electrolytes was measured. After immersing the sulfide solid electrolyte in a -40°C drying chamber for 24 hours, the ionic conductivity was measured again. In these examples, the ionic conductivity was obtained, for example, by the AC impedance method, and the measurement results are shown in Table 1.

[0069] Examples 1-32 and Comparative Examples 1-3 of the present invention provide lithium-ion batteries using different sulfide solid electrolytes. The lithium-ion batteries produced were subjected to long-cycle charge-discharge at 25°C, their discharge capacity was measured, and their energy density was calculated. The operating voltage range for battery measurement was 2.5V to 4.3V. The charge-discharge ratio was 1C / 1C. The discharge capacity of the first cycle was recorded and defined as the 1C discharge capacity. Measurement was terminated when the battery capacity reached 80% of the first cycle capacity (80% State of Health, 80% SOH), and the number of cycles at room temperature was obtained. A symmetric cell was measured at 1mA / cm². 2 Constant current charge-discharge cycle measurements were performed under the specified current density, and the measurement results are shown in Table 2.

[0070] Table 1 shows the ionic conductivity of the sulfide solid electrolytes in Examples 1-32 and Comparative Examples 1-3.

[0071] [Table 1]

[0072] Table 2 shows the measurement results for lithium-ion batteries and symmetrical cells in Examples 1-32 and Comparative Examples 1-3.

[0073] [Table 2]

[0074] As shown in Tables 1 and 2, a comparison of Examples 1-32 and Comparative Examples 1-3 reveals that when M and O elements are not added to the electrolyte, lithium-ion batteries have almost no cycle performance and short circuits occur in a short time. This indicates that when M and O elements are deficient, the chemical stability of the sulfide solid electrolyte material is poor, the mechanical strength is insufficient, and it is difficult to guarantee the long-term cycle performance of lithium-ion batteries. By introducing M and O elements, the cycle performance of lithium-ion batteries can be improved.

[0075] As shown in Tables 1 and 2, a comparison of Examples 1-6 reveals that when Sb is selected as the M element in the sulfide solid electrolyte, the cycle performance of the lithium-ion battery increases gradually with increasing Sb doping, and then decreases gradually. A comparison of Examples 11-17 shows that when In is selected as the M element in the sulfide solid electrolyte, the cycle performance of the lithium-ion battery increases gradually with increasing In doping, and then decreases gradually. A comparison of Examples 22-28 shows that when Bi is selected as the M element in the sulfide solid electrolyte, the cycle performance of the lithium-ion battery increases gradually with increasing Bi doping, and then decreases gradually. In cases where the doping amount of Sb, In, or Bi was excessively low, or when the number of cycles was small, battery short circuits occurred. Furthermore, while the ionic conductivity of the sulfide solid electrolyte decreases with increasing M element doping, the retention rate of ionic conductivity after 24 hours of exposure in a -40°C drying chamber increases, strengthening the atmospheric and chemical stability of the sulfide solid electrolyte, thereby improving the stability and performance of the battery. Therefore, by controlling the amount of M doping in the sulfide solid electrolyte, the cycle life and safety of lithium batteries can be improved in all-solid-state lithium-ion batteries, while simultaneously maintaining a high level of ionic conductivity, ensuring the rate performance of lithium-ion batteries, and improving charge-discharge efficiency and cycle life. High ionic conductivity can reduce the internal resistance of the battery, improving the power density and energy density of the battery.

[0076] Please refer to Figure 1. In the room-temperature cycling process of the all-solid-state lithium-ion battery of Example 3, the current density used for constant current charging and discharging was 1C. As can be seen from Figure 1, at a current density of 1C, the all-solid-state lithium-ion battery of Example 3 still has a capacity of approximately 160 mAh / g after 500 cycles, demonstrating that the sulfide solid electrolyte has excellent reaction kinetics and cycle stability. The obtained solid electrolyte membrane effectively improves the battery's cycle stability and reaction activity ratio capacity, and the all-solid-state lithium-ion battery possesses excellent performance in terms of specific capacity, rate performance, and cycle life.

[0077] As shown in Figure 2, the morphological characteristics of the sulfide solid electrolyte obtained in Example 3 were evaluated, and scanning electron microscope (SEM) images were obtained. As can be seen from Figure 2, the sulfide electrolyte prepared using the ball mill method has an irregular morphology, and the particle size is 2-8 μm. This particle size is advantageous for maintaining relatively high ionic conductivity while simultaneously achieving good battery cycle stability.

[0078] As shown in Tables 1 and 2, a comparison of Examples 3, 7 and 8, Examples 13, 18 and 19, and Examples 24, 29 and 30 reveals that when the doping amounts of Sb, In, or Bi in the sulfide solid electrolyte are the same, increasing or decreasing the Cl content significantly reduces the ionic conductivity, thereby degrading the cycle performance of the lithium-ion battery. Therefore, controlling the Cl content ensures the ionic conductivity of the sulfide solid electrolyte and the performance of the lithium-ion battery.

[0079] As shown in Tables 1 and 2, a comparison of Examples 3, 9 and 10, Examples 13, 20 and 21, and Examples 24, 31 and 32 reveals that when the doping amounts of Sb, In, or Bi in the sulfide solid electrolyte are the same, doping with Br or one or more elements I all degrades the battery's cycle performance. Therefore, by selecting Cl as X, the ionic conductivity and electrochemical stability of the sulfide solid electrolyte can be improved, thereby improving voltage stability.

[0080] The present invention further provides electronic devices, each comprising at least one of the above-mentioned lithium-ion batteries, which are used to provide power. Here, the electronic devices can be vehicles, mobile phones, portable devices, laptop computers, ships, spacecraft, electric toys, and power tools, etc. In one embodiment of the present invention, a vehicle is, for example, a new energy vehicle, which can be a pure electric vehicle, a hybrid vehicle, or a range-extender vehicle, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, and electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric boat toys, and electric airplane toys, etc. Power tools include metal cutting power tools, polishing power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc. Since the electronic devices include the above-mentioned lithium-ion batteries, they include the above-mentioned advantages of lithium-ion batteries, which are not described in detail here.

[0081] As described above, the present invention provides a sulfide solid electrolyte, a method for preparing the same, and its applications. By introducing +3 or +5 valency M and O elements into the sulfide solid electrolyte, alloys such as LiCl, Li2O, and Li-Sb / Li-Bi / Li-In can be formed in the electrolyte / lithium metal anode interface layer, thereby homogenizing the electric field and equipping the local current density. This regulates Li nucleation and growth, effectively suppressing the rapid growth of lithium dendritic crystals at the growth interface, significantly improving the stability and performance of lithium-ion batteries, and enhancing the lifespan and safety of lithium batteries in all-solid-state lithium-ion batteries. The intrinsic resistance of the sulfide solid electrolyte to atmospheric degradation is improved, the generation of H2S is effectively reduced, increasing the battery's potential in actual production, thereby strengthening the atmospheric and chemical stability of the sulfide solid electrolyte. The sulfide solid electrolyte can be made to have relatively high stability and specific reactivity, improving the conductivity stability of the sulfide solid electrolyte, strengthening atmospheric stability, and improving the electrolyte / active material interface properties, thereby improving compatibility with the active material. This method can improve the ionic conductivity and electrochemical stability of sulfide solid electrolytes, thereby improving voltage stability.

[0082] The above description merely illustrates preferred embodiments and operational technical principles of the present invention. Those skilled in the art should understand that the scope of the invention is not limited to technical solutions formed by specific combinations of the above technical features, but also includes other technical solutions formed by arbitrary combinations of the above technical features or their equivalents, without departing from the conceptual framework of the invention. For example, technical solutions formed by substituting the above features with similar functional technical features disclosed in the present invention (but not limited to these).

[0083] Other technical features not described in the specification are known to those skilled in the art, and in order to highlight the innovative features of the present invention, these other technical features will not be described in detail here. [Industrial applicability]

[0084] This invention can be applied to the field of all-solid-state lithium-ion batteries.

Claims

1. The chemical formula is Li ａ P １－ｂ M ｂ S ｃ O ｄ X ｅ A sulfide solid electrolyte, Here, 5 < a < 6, 0 < b < 1, 1.5 < c < 5, 0 < d < 2.5, 4 < c + d < 5, 1 < e < 2, M is one or more selected from Al, Ga, In, Ti, Sc, As, Sb, Bi, V, or Nb. X is one or more elements selected from Cl, Br, or I. A sulfide solid electrolyte characterized by the following features.

2. M is one or more selected from Sb, In, or Bi. The sulfide solid electrolyte according to claim 1, characterized in that...

3. X is Cl, and the acceptable range for b is 0 < b ≤ 0.

1. The sulfide solid electrolyte according to claim 1, characterized in that...

4. Based on the chemical formula of the sulfide solid electrolyte, the Li source, P source, M source, S source, and X source are mixed according to stoichiometry, then placed in a ball mill pot and ground in a ball mill to obtain a sulfide solid electrolyte precursor powder. The process includes calcining the sulfide solid electrolyte precursor powder at a predetermined temperature to obtain the sulfide solid electrolyte. A method for preparing a sulfide solid electrolyte according to any one of claims 1 to 3, characterized in that

5. The Li source is LiCl, LiBr, LiI, or Li ２ One or more types selected from S, The P source is one or more selected from elemental P, P ２ S ５ , P ４ S ６ , PCl ５ , or PBr ５ and is one or more selected therefrom. The aforementioned M source is one or more selected from oxides of M or sulfides of M. The S source is a single S, Li ２ S, P ２ S ５ , P ４ S ６ As ２ S ５ As ２ S ３ Sb ２ S ５ Sb ２ S ３ , Bi ２ S ５ , Bi ２ S ３ Al ２ S ３ Ga ２ S ３ In ２ S ３ , or Sc ２ S ３ One or more selected from, The X source is LiCl, PCl ５ LiBr, PBr ５ , LiI, or I ２ One or more selected from, The element O in the chemical formula originates from an oxide of M. A method for preparing a sulfide solid electrolyte according to claim 4, characterized in that...

6. The ball mill grinding time is 1 to 48 hours, the ball mill rotation speed is 50 to 1500 rpm, and the ball-to-raw material ratio is 1:1 to 100:

1. A method for preparing a sulfide solid electrolyte according to claim 4, characterized in that...

7. The predetermined temperature is 400 to 600°C, and the firing process time is 1 to 18 hours. A method for preparing a sulfide solid electrolyte according to claim 4, characterized in that...

8. at least Li ２．３５ Zr ０．６５ Fe ０．３５ Cl ５ Br ０．５ I ０．５ A positive electrode sheet containing a halogenated solid electrolyte containing, Negative electrode sheet and A solid electrolyte membrane is installed between adjacent positive electrode sheets and negative electrode sheets and comprises a sulfide solid electrolyte according to any one of claims 1 to 3. A solid-state lithium-ion battery characterized by the following features.

9. The positive electrode sheet contains a positive electrode active material, The positive electrode active material is one or more selected from lithium nickel cobalt manganese oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel manganese oxide, lithium cobalt oxide, or lithium nickel cobalt aluminum oxide. The all-solid-state lithium-ion battery according to claim 8, characterized in that

10. Includes the all-solid-state lithium-ion battery described in claim 8. An electronic device characterized by the following features.

Images