A type of sulfide solid electrolyte and method for preparing the same, all-solid-state lithium-ion battery and electronic device.

Abstract

The present invention provides a sulfide solid electrolyte, a method for preparing the same, an all-solid-state lithium-ion battery, and electronic equipment, thereby enhancing the atmospheric stability and chemical stability of the sulfide solid electrolyte, improving its conductivity, enhancing atmospheric stability, and improving the electrolyte / active material interface properties. This improves compatibility with the active material, reduces the use of sealing processes and sealing materials, and significantly improves the capacity, cycle count, and energy density of the lithium-ion battery. [Solution] The present invention provides a sulfide solid electrolyte, 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] This invention relates to the field of lithium-ion batteries, and more specifically to sulfide solid electrolytes, methods for preparing them, and their applications.

[0002] This application claims priority to the Chinese patent application filed on October 11, 2024, application number 202411418926.2, with the title of invention "Sulfide Solid Electrolyte, Method for Preparation of the Same and its Applications," and all contents thereof are incorporated into this invention by reference. [Background technology]

[0003] Lithium-ion batteries are widely used as important energy storage devices in electric vehicles and electronic products. In conventional liquid lithium batteries, both sides of the current collector are made of the same electrode material, all electrodes are immersed in the same electrolyte, and each electrode is connected in parallel by external connecting wires, thus incorporating a large amount of inactive material into the battery system. This results in a significant loss of both the volumetric energy density and gravimetric energy density of the lithium-ion battery.

[0004] The introduction of bipolar batteries simplifies the battery structure and shape by eliminating the need for electrical connectors or other accessories, and significantly improves volumetric and gravimetric energy density. However, the flow of the liquid electrolyte in bipolar batteries can cause short circuits in the battery's electrolyte junction, requiring a complex sealing process. This consumes a large amount of sealing material, resulting in a loss of energy density. Solid electrolytes can solve the problems of liquid batteries due to their solid properties, but they have drawbacks such as poor chemical stability and incompatibility with electrode materials. [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 provided by the present invention, the atmospheric stability and chemical stability of the sulfide solid electrolyte can be enhanced, the conductivity of the sulfide solid electrolyte can be improved, the atmospheric stability can be enhanced, and the electrolyte / active material interfacial properties can be improved. Thereby, the compatibility with the active material can be improved, the use of the sealing process and the sealing material can be reduced, and the battery capacity, cycle number, and energy density of the bipolar battery can be significantly improved.

Means for Solving the Problems

[0006] To solve the above technical problems, the present invention is realized by the following technical solutions.

[0007] 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 wherein, 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, and X is one or more selected from Cl, Br, or I.

[0008] In one embodiment of the present invention, M is one or more selected from Sb, In, or Bi.

[0009] In one embodiment of the present invention, X is Cl. The allowable range of b is 0 < b < 0.1.

[0010] The present invention further provides a preparation method of the above sulfide solid electrolyte. The method includes the following steps. Based on the chemical formula of the sulfide solid electrolyte, after uniformly mixing the raw materials according to stoichiometry, put them into a ball mill pot and perform ball milling to obtain a sulfide solid electrolyte precursor powder. The sulfide solid electrolyte precursor powder is subjected to calcination treatment at a predetermined temperature to obtain the sulfide solid electrolyte.

[0011] In one embodiment of the present invention, the raw material comprises Li2S, LiX, P2S5, and an oxide corresponding to the element M, where X is one or more selected from Cl, Br, or I, and M is one or more selected from Al, Ga, In, Ti, Sc, As, Sb, Bi, V, or Nb.

[0012] In one embodiment of the present invention, the ball mill grinding time is 20 to 30 hours, the ball mill rotation speed is 500 to 600 rpm, and the ball-to-raw material ratio is 35:1 to 45:1.

[0013] In one embodiment of the present invention, the predetermined temperature is 450 to 550°C, and the firing treatment time is 20 to 30 hours.

[0014] Furthermore, the present invention provides an all-solid-state lithium-ion battery. This all-solid-state lithium-ion battery includes at least the following: A bipolar electrode sheet having a positive electrode active material layer and a negative electrode active material layer on both sides, wherein a plurality of such bipolar electrode sheets are arranged so that the positive electrode active material layer and the negative electrode active material layer are facing each other between adjacent bipolar electrode sheets. A solid electrolyte membrane is placed between adjacent bipolar electrode sheets. Here, the positive electrode active material layer, the negative electrode active material layer, and the solid electrolyte membrane contain the above-mentioned sulfide solid electrolyte.

[0015] In one embodiment of the present invention, the content of the sulfide solid electrolyte in the positive electrode active material layer or the negative electrode active material layer is 20 to 30% by mass.

[0016] In one embodiment of the present invention, the solid electrolyte membrane comprises the sulfide solid electrolyte and a binder, and the solid electrolyte membrane is obtained by a dry process or a wet process.

[0017] The present invention further provides an electronic device, which includes the all-solid-state lithium-ion battery described above. [Effects of the Invention]

[0018] As described above, the present invention provides a sulfide solid electrolyte, a method for preparing the same, and its applications. It improves the intrinsic resistance of the sulfide solid electrolyte to atmospheric degradation and effectively reduces H2S generation, increasing the feasibility of actual battery production. This enhances the atmospheric and chemical stability of the sulfide solid electrolyte. It enables the sulfide solid electrolyte to have relatively high stability and specific reactivity, improving its conductivity, enhancing atmospheric stability, and improving compatibility with active materials by improving electrolyte / active material interface properties. By stabilizing the substrate structure of the sulfide solid electrolyte, ionic conductivity and electrochemical stability can be improved, and voltage stability can be enhanced. By employing a solid electrolyte membrane in bipolar batteries, the sealing process can be reduced, simplifying the sealing process of bipolar batteries and significantly reducing the use of sealing materials. This significantly improves the battery capacity, cycle count, and energy density of bipolar batteries, while simultaneously improving the safety performance of lithium ions. [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 solution of the present invention will be described in more detail below in combination with some embodiments. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative labor belong to the protection scope of the present invention.

[0022] 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, 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. By introducing a trivalent or pentavalent M element and an O element into the sulfur-rich halogen element sulfide solid electrolyte, P-O bonds and M-S bonds are formed in the crystal structure. Thereby, the inherent resistance to atmospheric decomposition is increased, and the generation of H2S can be effectively reduced. Thereby, the possibility in the actual production of the battery is increased, and the atmospheric stability and chemical stability of the sulfide solid electrolyte can be enhanced.

[0023] In one embodiment of the present invention, M is, for example, one or more selected from Sb, In or Bi, and bonds such as formed Sb-S / Bi-S / In-S have relatively high bond energy, the chemical bond is relatively strong, and it is not easily damaged by external influences. Thereby, the sulfide solid electrolyte has relatively high stability and specific reactivity, can improve the conductivity of the sulfide solid electrolyte, enhance the air stability, and improve the electrolyte / active material interfacial properties. Thereby, the compatibility with the active material is improved. X is, for example, Cl. By introducing a halogen element, the sulfide solid electrolyte matrix structure is stabilized, the ionic conductivity and electrochemical stability are improved, and the voltage stability is improved. The allowable range of b is 0 < b < 0.1. In one embodiment of the present invention, when M is +5 valence, b is optimally 0.04. When M is +3 valence, b is optimally 0.02. Thereby, the battery capacity, cycle number and energy density of the lithium-ion battery are optimized.

[0024] The present invention further provides a method for preparing a sulfide solid electrolyte. The method includes at least the following steps. Based on the chemical formula of the sulfide solid electrolyte, the raw materials are uniformly mixed according to stoichiometry, then put into a ball mill pot and ball milled to obtain a sulfide solid electrolyte precursor powder. The sulfide solid electrolyte precursor powder is fired at a predetermined temperature to obtain the sulfide solid electrolyte.

[0025] In one embodiment of the present invention, the chemical formula of the sulfide solid electrolyte is Li a P 1-b M b S c O d X eBased on this, the raw materials are uniformly mixed according to stoichiometry. Here, the raw materials include, for example, Li2S, LiX, P2S5, and oxides corresponding to element M, where X is one or more selected from, for example, Cl, Br, or I. M is one or more selected from, for example, Al, Ga, In, Ti, Sc, As, Sb, Bi, As, V, or Nb. After uniformly mixing the raw materials, they are placed in a ball mill pot to obtain sulfide solid electrolyte precursor powder. Here, the ratio of balls to raw materials is, for example, 35:1 to 45:1, the ball mill rotation speed is, for example, 500 to 600 rpm, and the ball mill grinding time is, for example, 20 to 30 hours.

[0026] In one embodiment of the present invention, a sulfide solid electrolyte precursor powder is subjected to calcination treatment at a predetermined temperature to obtain a sulfide solid electrolyte. Here, the predetermined temperature is 450 to 550°C, and the calcination treatment time is 20 to 30 hours.

[0027] The present invention further provides an all-solid-state lithium-ion battery. The all-solid-state lithium-ion battery includes a plurality of bipolar electrode sheets and a solid electrolyte membrane. A positive electrode active material layer and a negative electrode active material layer are provided on both sides of the bipolar electrode sheets, respectively, and the positive electrode active material layer and negative electrode active material layer between adjacent bipolar electrode sheets are positioned opposite each other, and the solid electrolyte membrane is provided between adjacent bipolar electrode sheets. Here, the above-mentioned sulfide solid electrolyte is included in either the positive electrode active material layer, the negative electrode active material layer, or the solid electrolyte membrane, thereby improving the performance of the all-solid-state lithium-ion battery.

[0028] In one embodiment of the present invention, the solid electrolyte membrane is prepared, for example, by a dry process, and specifically, Li as the sulfide solid electrolyte. a P 1-b M b S c O d X eThe mixture is mixed with a dry process binder in a mass ratio of, for example, 99.5:0.5 to 96:4, and then polished repeatedly in a mortar. After that, the mixture is roll-rolled manually to form a film, and then roll-rolled again in a vertical roll mill until a predetermined thickness is reached. Here, the dry process binder is, for example, polytetrafluoroethylene (PTFE) and its derivatives. In one embodiment of the present invention, the predetermined thickness of the solid electrolyte film is, for example, 10 to 20 μm, and by combining the sulfide solid electrolyte with the binder, the processing performance of the sulfide solid electrolyte can be greatly improved and the mechanical stability of the solid electrolyte film can be enhanced.

[0029] In another embodiment of the present invention, the solid electrolyte membrane is prepared, for example, by a wet process. Specifically, a wet process binder is dissolved in an organic solvent to a predetermined concentration, and then Li is added as a sulfide solid electrolyte based on the mass ratio. a P 1-b M b S c O d X eThe following are added and mixed uniformly to obtain a solid electrolyte slurry. The solid electrolyte slurry is then applied to a mold, for example, by a coating machine, the organic solvent is evaporated at room temperature, and then it is dried in a vacuum dryer and demolded. Here, the wet process binder includes, but is not limited to, one or more of the following: fluororubber, polyvinylidene difluoride (PVDF) and its derivatives, or hydrogenated nitrile rubber (HNBR) and its derivatives. The organic solvent is, for example, butyl butyrate. The predetermined concentration is, for example, 8 to 12% by mass. The mass ratio of the sulfide solid electrolyte to the wet process binder is, for example, 99.5:0.5 to 96:4. The predetermined thickness of the final obtained solid electrolyte film is, for example, 10 to 20 μm. In another embodiment of the present invention, a porous high-strength substrate such as a nonwoven fabric or polyimide is used as a support, and the solid electrolyte slurry is applied to it to obtain a solid electrolyte film. By controlling the mass ratio of the sulfide solid electrolyte and the binder, we can achieve both film formation performance and conductivity of the solid electrolyte film.

[0030] In one embodiment of the present invention, the bipolar electrode sheet includes a bipolar current collector and a positive electrode active material layer and a negative electrode active material layer, respectively, placed on both side surfaces of the bipolar current collector. Here, the bipolar current collector includes, for example, a positive electrode conductive layer, an adhesive conductive layer, and a negative electrode conductive layer, the adhesive conductive layer being placed between the positive electrode conductive layer and the negative electrode conductive layer. In one embodiment of the present invention, the positive electrode conductive layer includes, but is not limited to, at least one of the following: aluminum, aluminum alloy, titanium, nickel, magnesium, or magnesium. The negative electrode conductive layer includes, but is not limited to, at least one of the following: copper, copper alloy, nickel, nickel alloy, or stainless steel. The material of the adhesive conductive layer includes, but is not limited to, at least one of the following: conductive carbon black, acetylene black, conductive graphite, conductive carbon nanotubes, conductive fibers, aluminum metal, or copper metal. The present invention does not limit the thickness of the positive electrode conductive layer, the adhesive conductive layer, and the negative electrode conductive layer, and is specifically selected based on manufacturing requirements. In one specific embodiment of the present invention, the thickness of the positive electrode conductive layer is, for example, 8 to 10 μm, the thickness of the adhesive conductive layer is, for example, 4 to 9 μm, and the thickness of the negative electrode conductive layer is, for example, 8 to 10 μm.

[0031] In one embodiment of the present invention, the positive electrode active material layer is placed on the positive electrode conductive layer. The positive electrode active material layer comprises a positive electrode active material, a conductive agent, a binder, and the above-mentioned sulfide solid electrolyte, and the present invention does not specifically limit the types of the positive electrode active material, conductive agent, and binder. Materials usable in lithium-ion batteries known in the art can be used, and those skilled in the art can select them based on actual needs. In one embodiment of the present invention, the positive electrode active material includes, but is not limited to, one or more of the following: lithium cobalt oxide (LCO), lithium nickel oxide (LNO), lithium manganese oxide (LMO), lithium nickel manganese oxide (LNMO), lithium nickel cobalt manganese oxide (NCM), lithium nickel cobalt aluminum oxide (NCA), lithium-rich manganese oxide (LRMO), and lithium-containing phosphates. The lithium-containing phosphate includes, but is not limited to, lithium iron manganese phosphate, lithium iron phosphate, and lithium manganese phosphate. The binder is selected from, for example, polyvinylidene fluoride or polytetrafluoroethylene. The conductive agent is selected from, for example, carbon black, acetylene black, graphene, carbon nanotubes, or carbon nanofibers, or is a combination of two or more such agents mixed in any ratio. In the positive electrode active material layer, the mass ratio of the positive electrode active material, conductive agent, binder, and sulfide solid electrolyte is, for example, (61-88):(1-2):(1-2):(20-25).

[0032] In one embodiment of the present invention, the negative electrode active material layer is placed on the negative electrode conductive layer. The negative electrode active material layer comprises a negative electrode active material, a conductive agent, a binder, and the above-mentioned sulfide solid electrolyte. The present invention does not specifically limit the types of negative electrode active material, conductive agent, and binder, and materials usable in lithium-ion batteries known in the art can be used, and those skilled in the art can select them based on their actual needs. In one embodiment of the present invention, the negative electrode active material includes, but is not limited to, one or more of the following: artificial graphite, natural graphite, soft carbon, hard carbon, pure silicon, silicon oxide, or silicon-carbon compounds. The conductive agent is selected from, for example, carbon black, acetylene black, graphene, carbon nanotubes, or carbon nanofibers, or a combination of two or more of these in any ratio. The binder is selected from any one of the following, or a combination of several of them mixed in any ratio: polyacrylic acid (PAA), lithium acrylate (PAALi), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), or polymerized styrene butadiene rubber (SBR). In the negative electrode active material layer, the mass ratio of the negative electrode active material, conductive agent, binder, and sulfide solid electrolyte is, for example, (61-88):(1-2):(1-2):(20-25).

[0033] In one embodiment of the present invention, a positive electrode active material, a conductive agent, a binder, and a sulfide solid electrolyte are dispersed in a nonpolar solvent based on a mass ratio to form a uniform positive electrode slurry. Here, the nonpolar solvent is, for example, xylene. The positive electrode slurry is applied onto the positive electrode conductive layer (i.e., the current collector) of a bipolar current collector, and a positive electrode active material layer is formed on the bipolar current collector through processes such as drying and cold pressing. A negative electrode active material, a conductive agent, a binder, and a sulfide solid electrolyte are dispersed in a nonpolar solvent based on a mass ratio to form a uniform negative electrode slurry. Here, the nonpolar solvent is, for example, xylene. The negative electrode slurry is applied onto the negative electrode conductive layer of the bipolar current collector on which the positive electrode active material layer has been formed, and a bipolar electrode sheet is obtained through processes such as drying and cold pressing. In other embodiments, the present invention does not limit the method, process, etc., for preparing the positive electrode active material layer and the negative electrode active material layer, and a dry process may be employed.

[0034] In one embodiment of the present invention, a plurality of bipolar electrode sheets are stacked. In the process of sequentially stacking the plurality of bipolar electrode sheets along the stacking direction, the positive electrode active material layer and the negative electrode active material layer of adjacent bipolar electrode sheets are placed facing each other, and a solid electrolyte membrane is placed between the adjacently stacked electrodes. The solid electrolyte membrane is placed between the positive electrode active material layer and the negative electrode active material layer of adjacent bipolar electrode sheets to complete the series connection of the plurality of bipolar electrode sheets, and finally a bipolar battery having, for example, 10 battery units is formed. Finally, an aluminum plastic film is sealed on the outside of the bipolar battery to complete a single sealing process. After that, processes such as chemical conversion, volume reduction, and aging are carried out. By employing a solid electrolyte membrane in the bipolar battery, the sealing process can be reduced, the use of sealing material can be greatly reduced, and the energy density of the bipolar battery can be greatly improved. At the same time, the all-solid-state lithium-ion battery avoids the use of electrolyte, and the safety performance of the lithium-ion battery can also be improved.

[0035] 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.

[0036] Example 1 Li as a sulfide solid electrolyte 5.5 P 0.98 In 0.02 S3O 1.5 Cl 1.46 The mixture was mixed with PTFE as a binder in a mass ratio of 99:1, placed in a mortar, and repeatedly polished. After that, the mixture was rolled manually to form a film, and then rolled again in a vertical roll mill until it reached a thickness of 15 μm to obtain a solid electrolyte film. The positive electrode conductive layer of the bipolar current collector is aluminum foil with a thickness of 8 μm. The adhesive conductive layer is conductive carbon black with a thickness of 5 μm. The negative electrode conductive layer is copper foil with a thickness of 8 μm. LiNi 0.9 Co 0.05 Mn 0.05 O2, carbon black, polyvinylidene fluoride, and Li 5.5 P 0.98 In 0.02 S3O 1.5 Cl 1.46 After mixing the materials in a mass ratio of 75:1:1:23, xylene was added and the mixture was stirred until the system was homogeneous to obtain a positive electrode slurry. The positive electrode slurry was uniformly applied to the positive electrode conductive layer of a bipolar current collector, and after drying, cold pressing, and other processes, a positive electrode active material layer was obtained. Silicon-carbon compound, carbon black, styrene-butadiene rubber and Li 5.5 P 0.98 In 0.02 S3O 1.5 Cl 1.46 After mixing the materials in a mass ratio of 75:1:1:23, xylene was added and the mixture was stirred until the system was homogeneous to obtain a negative electrode slurry. The negative electrode slurry was uniformly applied to the negative electrode conductive layer of a bipolar current collector, and after drying, cold pressing, and other processes, a bipolar electrode sheet was obtained. A bipolar electrode sheet and a solid electrolyte membrane were assembled, then sealed, converted, divided, and aged to obtain an all-solid-state lithium-ion battery.

[0037] Example 2 The solid electrolyte membrane is obtained by a wet process. Li 5.5 P 0.98 In 0.02 S3O 1.5 Cl 1.46 The material was prepared in the same manner as in Example 1, except that the mass ratio of the binder fluororubber was changed to 99:1.

[0038] Example 3 The sulfide solid electrolyte in the solid electrolyte membrane and bipolar electrode sheet is Li 5.5 P 0.97 In 0.03 S3O 1.5 Cl 1.44 It was prepared in the same manner as in Example 1, except for the change made to [specific part].

[0039] Example 4 The sulfide solid electrolyte in the solid electrolyte membrane and bipolar electrode sheet is Li 5.5 P 0.99 In 0.01 S3O 1.5 Cl 1.48 It was prepared in the same manner as in Example 1, except for the change made to [specific part].

[0040] Example 5 The sulfide solid electrolyte in the solid electrolyte membrane and bipolar electrode sheet is Li 5.5 P 0.98 Al 0.02 S3O 1.5 Cl 1.46 It was prepared in the same manner as in Example 1, except for the change made to [specific part].

[0041] Example 6 The sulfide solid electrolyte in the solid electrolyte membrane and bipolar electrode sheet is Li 5.5 P 0.98 Ga 0.02 S3O 1.5 Cl 1.46 It was prepared in the same manner as in Example 1, except for the change made to [specific part].

[0042] Example 7 The sulfide solid electrolyte in the solid electrolyte membrane and the bipolar electrode sheet was changed to Li 5.5 P 0.98 Sb 0.02 S3O 1.5 Cl 1.46 and fabricated in the same manner as Example 1 except for the change.

[0043] Example 8 The sulfide solid electrolyte in the solid electrolyte membrane and the bipolar electrode sheet was changed to Li 5.5 P 0.98 Bi 0.02 S3O 1.5 Cl 1.46 and fabricated in the same manner as Example 1 except for the change.

[0044] Example 9 The sulfide solid electrolyte in the solid electrolyte membrane and the bipolar electrode sheet was changed to Li 5.5 P,,, 0.98 Sc 0.02 S3O 1.5 Cl 1.46 and fabricated in the same manner as Example 1 except for the change.

[0045] Example 10 The sulfide solid electrolyte in the solid electrolyte membrane and the bipolar electrode sheet was changed to Li 5.5 P 0.98 Ti 0.02 S3O 1.5 Cl 1.46 and fabricated in the same manner as Example 1 except for the change.

[0046] Example 11 The sulfide solid electrolyte in the solid electrolyte membrane and the bipolar electrode sheet was changed to Li 5.5 ..P 0.98 As 0.02 S3O 1.5 Cl 1.46 and fabricated in the same manner as Example 1 except for the change.

[0047] Example 12 The sulfide solid electrolyte in the solid electrolyte membrane and bipolar electrode sheet is Li 5.5 P 0.96 As 0.04 S3O 1.5 Cl 1.5 It was prepared in the same manner as in Example 1, except for the change made to [specific part].

[0048] Example 13 The sulfide solid electrolyte in the solid electrolyte membrane and bipolar electrode sheet is Li 5.5 P 0.92 As 0.08 S3O 1.5 Cl 1.5 It was prepared in the same manner as in Example 1, except for the change made to [specific part].

[0049] Example 14 The sulfide solid electrolyte in the solid electrolyte membrane and bipolar electrode sheet is Li 5.5 P 0.96 V 0.04 S3O 1.5 Cl 1.5 It was prepared in the same manner as in Example 1, except that it was changed to [this].

[0050] Example 15 The sulfide solid electrolyte in the solid electrolyte membrane and bipolar electrode sheet is Li 5.5 P 0.96 Nb 0.04 S3O 1.5 Cl 1.5 It was prepared in the same manner as in Example 1, except for the change made to [specific part].

[0051] Example 16 The sulfide solid electrolyte in the solid electrolyte membrane and bipolar electrode sheet is Li 5.5 P 0.98 In 0.02 S3O 1.5 Br 1.46 It was prepared in the same manner as in Example 1, except for the change made to [specific part].

[0052] Example 17 The sulfide solid electrolyte in the solid electrolyte membrane and bipolar electrode sheet is Li 5.5 P 0.98 In0.02 S3O 1.5 I 1.46 It was prepared in the same manner as in Example 1, except for the change made to [specific part].

[0053] Comparative Example 1 The solid electrolyte membrane is replaced with an electrolyte solution. In this electrolyte solution, the lithium salt is LiPF6, the solvents are ethylene carbonate (EC) and diethyl carbonate (DEC), the mass ratio of EC and DEC in the solvent is 3:7, and the LiPF6 concentration in the electrolyte solution is 1 mol / L. The other procedures were carried out in the same manner as in Example 1.

[0054] Comparative Example 2 The preparation was carried out in the same manner as in Comparative Example 1, except that the mass ratio of EC and DEC in the solvent was changed to 5:5.

[0055] Comparative Example 3 The preparation was carried out in the same manner as in Comparative Example 1, except that diethyl carbonate was replaced with propylene carbonate (PC).

[0056] In Examples 1-17 and Comparative Examples 1-3 of the present invention, lithium-ion batteries were obtained by employing different sulfide solid electrolytes and preparation methods. Long-cycle charge-discharge was performed on the prepared lithium-ion batteries at 25°C, and their discharge capacity was measured and their energy density was calculated. The operating voltage range for the battery test was 2.8-4.3V, and the charge-discharge ratio was 1C / 1C. The discharge capacity of the first cycle was recorded and defined as the 1C discharge capacity. The test 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.

[0057] Table 1 shows the performance test results of lithium-ion batteries for Examples 1-17 and Comparative Examples 1-3.

[0058] [Table 1]

[0059] Please refer to Table 1. Comparing Examples 1 to 17 with Comparative Examples 1 to 3, it has been shown that when a solid-state bipolar battery is fabricated using the sulfide solid electrolyte of the present invention, the capacity, number of cycles, and energy density of the lithium-ion battery can be improved. In an example where the positive electrode active material is a ternary system (NCM positive electrode chemistry with a nickel content of 90% or more) and the negative electrode is a silicon-based negative electrode, the energy density of the lithium-ion battery can reach 450 Wh / kg or more with a matched designed sulfide solid electrolyte. Moreover, a full battery with only a single final sealing can stably cycle for 1000 cycles or more. Therefore, the sealing process and the use of sealing materials can be reduced, and the energy density of the battery can be significantly improved. On the other hand, after replacing the solid electrolyte membrane with an electrolytic solution, the lithium-ion battery will short-circuit. Thus, by applying the sulfide solid electrolyte to the bipolar battery, the sealing process of the bipolar battery can be simplified, and the performance of the bipolar battery can be improved.

[0060] Please refer to Table 1. Comparing Example 1 and 2, when different fabrication processes for the solid electrolyte membrane are adopted, such as the dry process preparation and the wet process, the performance of the lithium-ion electrode is comparable. This indicates that by adopting different preparation methods, the obtained solid electrolyte membrane can equally improve the performance of the lithium-ion battery. Comparing Examples 1, 3, 4 with Examples 11 to 13, when the content of M in Li a P 1-b M b S c O d X e as the sulfide solid electrolyte changes from low to high, the capacity, number of cycles, and energy density of the lithium-ion battery first increase and then decrease. This shows that the allowable range of b is preferably 0 < b < 0.1, and when M is +5 valence, b is preferably 0.04, and when M is +3 valence, b is preferably 0.02. This indicates that the battery capacity, number of cycles, and energy density of the lithium-ion battery can be optimally achieved.

[0061] Please refer to Table 1. Comparing Examples 1 with 5-10 and Examples 12 with 14-15, Li as a sulfide solid electrolyte... a P 1-b M b S c O d X e When different +3-valent or +5-valent elements are selected for M in and b is selected for the optimal content, the battery capacity, cycle count, and energy density of the lithium-ion battery are all maintained in a higher numerical range. This indicates that by selecting different M elements, the performance of the lithium-ion battery can be improved. Comparing Examples 1 and 16-17, Li as a sulfide solid electrolyte a P 1-b M b S c O d X e When X in the equation is selected from a different halogen atom, the battery capacity, cycle count, and energy density of the lithium-ion battery are all maintained within a higher numerical range, and the performance of the lithium-ion battery is optimal when Cl is selected as the halogen atom.

[0062] 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.

[0063] 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, PO bonds and MS bonds are formed in the crystal structure, thereby increasing the intrinsic resistance to atmospheric decomposition, effectively reducing H2S generation, increasing the battery's potential in actual production, and thereby enhancing 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 its conductivity, enhancing atmospheric stability, and improving the electrolyte / active material interface properties, thereby improving compatibility with the active material. By introducing halogen elements, the sulfide solid electrolyte substrate structure is stabilized, improving ionic conductivity and electrochemical stability, and improving voltage stability. By adopting a solid electrolyte membrane in a bipolar battery, the sealing process is reduced, simplifying the sealing process of the bipolar battery and significantly reducing the use of sealing materials, thereby significantly improving the battery capacity, cycle count, and energy density of the bipolar battery, while simultaneously improving the safety performance of lithium ions.

[0064] 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).

[0065] 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]

[0066] The sulfide solid electrolyte, its preparation method, and its applications according to the present invention can be used in the field of lithium-ion battery technology.

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 elements 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 raw materials are uniformly 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 raw material is Li ２ S, LiX, P ２ S ５ , and includes oxides corresponding to the M element X is one or more elements selected from Cl, Br, or I. M is one or more elements selected from Al, Ga, In, Ti, Sc, As, Sb, Bi, V, or Nb. A method for preparing a sulfide solid electrolyte according to claim 4, characterized in that...

6. The ball mill grinding time is 20 to 30 hours, the ball mill rotation speed is 500 to 600 rpm, and the ball-to-raw material ratio is 35:1 to 45:

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

7. The predetermined temperature is 450 to 550°C, and the firing process time is 20 to 30 hours. A method for preparing a sulfide solid electrolyte according to claim 4, characterized in that...

8. at least A bipolar electrode sheet having a positive electrode active material layer and a negative electrode active material layer on both sides, wherein the positive electrode active material layer and the negative electrode active material layer are positioned opposite each other between adjacent bipolar electrode sheets, comprising a plurality of such bipolar electrode sheets, A solid electrolyte membrane is placed between adjacent bipolar electrode sheets, Includes, The positive electrode active material layer, the negative electrode active material layer, and the solid electrolyte membrane include the sulfide solid electrolyte described in any one of claims 1 to 3. A solid-state lithium-ion battery characterized by the following features.

9. The content of the sulfide solid electrolyte in the positive electrode active material layer or the negative electrode active material layer is 20 to 30% by mass. The all-solid-state lithium-ion battery according to claim 8, characterized in that

10. The solid electrolyte membrane comprises the sulfide solid electrolyte and a binder. The solid electrolyte membrane is obtained by a dry process or a wet process. The all-solid-state lithium-ion battery according to claim 8, characterized in that

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

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