Solid electrolyte membrane and method for preparing the same, all-solid-state lithium-ion battery, and electronic device

Abstract

By providing a solid electrolyte membrane, a method for preparing the same, and applications thereof, it is possible to improve the stability of the conductivity of the solid electrolyte membrane, enhance the air stability, and improve the lifespan and safety of lithium batteries in all-solid-state lithium-ion batteries. 【Solution means】The present invention provides a solid electrolyte membrane, a method for preparing the same, an all-solid-state lithium-ion battery, and an electronic device. The solid electrolyte membrane includes a binder and a sulfide solid electrolyte, and the molecular formula of the sulfide solid electrolyte is Li f P 1-g E g S w O g Q z wherein, 5 < f < 10, 0 < g < 1, 3 < w < 6, 4 < w + g < 6, 0 < z < 2, E is one or more selected from Mg, Ca, Sr, Ba, Zn, Cr, Sn or Pb, Q is one or more selected from Cl, Br or I, and the ionic conductivity of the solid electrolyte membrane is 1×10 -3 ~2×10 -2 S / cm.

Description

[Technical Field]

[0001] This invention relates to the field of lithium-ion batteries, and more specifically to solid electrolyte membranes, methods for preparing them, and their applications. [Background technology]

[0002] With the rapid development of new energy technologies, lithium-ion batteries are widely used due to their advantages such as high energy density and long cycle life. However, conventional lithium-ion batteries use liquid electrolytes, which present safety problems such as electrolyte leakage and combustion. To overcome these drawbacks, solid electrolyte materials are attracting widespread attention. Among these, sulfide solid electrolytes are attracting considerable attention due to their high ionic conductivity and good mechanical properties. Currently, Li 10 GeP2S 12 Various sulfide solid electrolyte materials such as Li6PS5Cl have been developed.

[0003] However, most current sulfide electrolytes have poor chemical stability, decompose easily in air, and produce toxic hydrogen sulfide gas, posing a threat to the environment and human health. Furthermore, strict manufacturing conditions increase production complexity and cost. Additionally, the interfacial compatibility between the sulfide solid electrolyte and the electrode material needs improvement, as high interfacial resistance affects battery performance. [Overview of the project] [Problems that the invention aims to solve]

[0004] This invention provides a solid electrolyte membrane, a method for preparing the same, and its applications. The solid electrolyte membrane, its preparation method, and its applications provided by this invention can improve the conductivity stability of the solid electrolyte membrane, enhance its stability in air, and improve the properties of the electrolyte / active material interface. This can improve the lifespan and safety of lithium batteries in all-solid-state lithium-ion batteries. [Means for solving the problem]

[0005] To solve the above technical problems, the present invention provides a solid electrolyte membrane. The solid electrolyte membrane at least comprises a binder, a sulfide solid electrolyte, and the molecular formula of the sulfide solid electrolyte is Li f P 1-g E g S w O g Q z where in the formula, 5 < f < 10, 0 < g < 1, 3 < w < 6, 4 < w + g < 6, 0 < z < 2, E is one or more selected from Mg, Ca, Sr, Ba, Zn, Cr, Sn or Pb, and Q is one or more selected from Cl, Br or I; the ionic conductivity is 1×10 -3 ~2×10 -2 S / cm.

[0006] In one embodiment of the present invention, E is Mg.

[0007] In one embodiment of the present invention, Q is Cl, and the allowable range of g is 0.01 ≦ g ≦ 0.1.

[0008] In one embodiment of the present invention, the thickness of the solid electrolyte membrane is 1~200 μm.

[0009] In one embodiment of the present invention, the mass ratio of the binder to the sulfide solid electrolyte is 0.1:99.9~10:90.

[0010] The present invention also provides a method for preparing the above solid electrolyte membrane. The method comprises based on the chemical formula of the sulfide solid electrolyte, uniformly mixing raw materials according to stoichiometry, then putting them into a ball mill pot and performing ball mill pulverization to obtain sulfide solid electrolyte precursor powder; performing firing treatment on the sulfide solid electrolyte precursor powder at a predetermined temperature to obtain the sulfide solid electrolyte; The method includes mixing the sulfide solid electrolyte with a binder and obtaining the solid electrolyte film by a dry or wet process.

[0011] 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 E source is one or more selected from oxides of E or sulfides of E; the S source is one or more selected from elemental S, Li2S, P2S5, P4S6, MgS, CaS, SrS, BaS, ZnS, CrS, SnS, or PbS; the Q 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 an oxide of E.

[0012] In one embodiment of the present invention, when the solid electrolyte membrane is prepared by a dry process, the binder is selected from a first binder, and the first binder is one or more selected from polytetrafluoroethylene, ethylene-tetrafluoroethylene copolymer, fluorinated ethylene propylene copolymer, perfluoroalkoxy resin, polychlorotrifluoroethylene, ethylene-chlorotrifluoroethylene copolymer, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, or polyvinylidene fluoride-chlorotrifluoroethylene copolymer.

[0013] In one embodiment of the present invention, when the solid electrolyte membrane is prepared by a wet process, the binder is selected from a second binder, and the second binder is one or more selected from polyvinylidene fluoride, carboxymethylcellulose, styrene-butadiene rubber, polyvinylpyrrolidone, polymethyl methacrylate, polyacrylonitrile, polyacrylic acid, polyurethane, polyvinyl alcohol, sodium alginate, ethylene-propylene-diene monomer, styrene-butadiene rubber, fluororubber, β-cyclodextrin polymer, polypropylene emulsion, polytetrafluoroethylene, ethylene-tetrafluoroethylene copolymer, fluorinated ethylene-propylene copolymer, perfluoroalkoxy resin, polychlorotrifluoroethylene, ethylene-chlorotrifluoroethylene copolymer, polyvinylidene fluoride-hexafluoropropylene copolymer, or polyvinylidene fluoride-chlorotrifluoroethylene copolymer copolymer.

[0014] Furthermore, the present invention provides an all-solid-state lithium-ion battery. This battery is, Li 2.35 Zr 0.65 Fe 0.35 Cl5Br 0.5 I 0.5 A positive electrode sheet containing a halogenated solid electrolyte containing, Negative electrode sheet and The system includes at least a solid electrolyte membrane, which is placed between adjacent positive electrode sheets and negative electrode sheets and is selected from the above-mentioned solid electrolyte membranes.

[0015] The present invention also provides electronic devices including the above-described all-solid-state lithium-ion battery. [Effects of the Invention]

[0016] In summary, the present invention provides a solid electrolyte membrane, a method for preparing the same, and its applications. By introducing elements E, O, and Q into the sulfide solid electrolyte in the solid electrolyte membrane, the air stability of the solid electrolyte membrane is effectively improved, and the amount of H2S gas generated by degradation in the atmosphere is reduced. This enhances the air stability and chemical stability of the solid electrolyte membrane. A special interfacial layer can be formed at the electrolyte / lithium metal anode interface, ensuring the ionic conductivity of the solid electrolyte membrane and promoting high-speed lithium ion movement and uniform electric field distribution. This contributes to controlling lithium nucleation and growth, preventing the formation of lithium dendritic crystals, significantly improving the stability and performance of lithium-ion batteries, enhancing the lifespan and safety of lithium batteries in all-solid-state lithium-ion batteries, and improving the compatibility between the solid electrolyte membrane and the active material. [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 is a schematic diagram of the process for preparing a solid electrolyte membrane by a dry process in one embodiment of the present invention. [Figure 2] The figure shows the 1C / 1C long-term cycle performance at room temperature for the all-solid-state lithium-ion battery of Example 3. [Modes for carrying out the invention]

[0019] The embodiments of the present invention will be described below with specific examples, and those skilled in the art will readily understand other advantages and effects of the present invention from the contents disclosed herein. Furthermore, the present invention can be implemented or applied in other different specific embodiments, and the details of each item herein can 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 presented 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 disclosed embodiments, which further describe the technical solutions of the present invention in combination with several examples below, represent only a portion of the embodiments of the present invention and are clearly not all embodiments. All other embodiments that a person skilled in the art could appropriately modify based on the embodiments of the present invention in accordance with the technical concept of the present invention are within the scope of the protection of the present invention.

[0022] This invention provides a solid electrolyte membrane. The solid electrolyte membrane comprises a binder and a sulfide solid electrolyte, the molecular formula of which is Li f P 1-g E g S w O g Q zHere, 5 < f < 10, 0 < g < 1, 3 < w < 6, 4 < w + g < 6, 0 < z < 2, E is one or more selected from Mg, Ca, Sr, Ba, Zn, Cr, Sn or Pb, and Q is one or more selected from Cl, Br or I. Here, by introducing E element and O element into the sulfide solid electrolyte rich in halogen elements, P-O and E-S bonds are formed in the crystal structure, and the air stability of the sulfide solid electrolyte can be effectively improved. Thereby, the H2S gas generated by atmospheric decomposition is reduced, and the air stability and chemical stability of the sulfide solid electrolyte are enhanced. Furthermore, when assembling an all-solid-state lithium-ion battery using the sulfide solid electrolyte, a special interface layer can be formed at the electrolyte / lithium metal negative electrode interface, and this interface layer contains components such as LiCl, Li2O and Li-Mg alloy. Here, Li2O has good ionic conductivity, and Li-Mg alloy promotes the fast movement of lithium ions and the uniform distribution of the electric field. The high interfacial energy of LiCl is beneficial to controlling the nucleation and growth of lithium and preventing the formation of lithium dendrites. Summarizing these characteristics, the diffusion of lithium ions between electrodes can be effectively promoted, and the growth of lithium dendrites can be suppressed. Therefore, the sulfide solid electrolyte provided by the present invention can significantly improve the stability and performance of lithium-ion batteries, and it is possible to improve the lifespan and safety of all-solid-state lithium-ion batteries.

[0023] In one embodiment of the present invention, E is selected from, for example, Mg. By Mg doping, the localization of electrons around S atoms is promoted, and the electron acceptance of Li is suppressed. At the same time, the self-limiting interface generated suppresses the redox reaction between the sulfide electrolyte and Li metal. That is, by Mg doping, the electron distribution in the sulfide solid electrolyte can be adjusted, and by suppressing the electron acceptance of Li, the parasitic redox reaction between the electrolyte and metallic lithium is reduced, the cycle stability and performance of the battery are improved, and the practicality and reliability of the sulfide electrolyte are improved.

[0024] In one embodiment of the present invention, Q is selected as a halogen element. Depending on the halogen element, the degree of anionic disorder between the 4a and 4c sites in the sulfide solid electrolyte crystal structure differs. This ranges from a small amount of antisite defects when Q is I to 60% site disorder when Q is Cl. The lithium conductivity of these compounds depends mainly on the degree of disorder in the anionic and cation site occupation. Therefore, selecting Cl as Q, for example, improves the ionic conductivity and electrochemical stability of the sulfide solid electrolyte and improves voltage stability. The acceptable range for g is 0.01 ≤ g ≤ 0.1. If the doping amount is too low, an effective interfacial layer may not be formed. Excessive doping causes excessive lattice strain and destroys the original crystal structure, thus reducing the structural stability of the material. Furthermore, phase separation and amorphous phenomena may occur, thereby reducing the ionic conductivity of the material. In one specific embodiment of the present invention, g is most preferably 0.02 in order to improve the cycle performance of the lithium-ion battery.

[0025] In one embodiment of the present invention, the thickness of the solid electrolyte membrane is, for example, 1 to 200 μm, and the ionic conductivity is, for example, 1 × 10⁻⁶. -3 ~2×10 -2 The conductivity is S / cm. Furthermore, the ionic conductivity is relatively stable at low temperatures, allowing for batch preparation of solid electrolyte membranes in a low-dew-point drying chamber, which greatly simplifies the preparation process and reduces preparation costs. The solid electrolyte membrane provided by this invention can be well matched with lithium metal negative electrodes, enabling the preparation of high-energy-density and high-performance all-solid-state lithium batteries.

[0026] In one embodiment of the present invention, the mass ratio of the binder to the sulfide solid electrolyte is 0.1:99.9 to 10:90, and the binder is one or more selected from the first binder or the second binder. Here, the first binder is selected from one or more of the following: polytetrafluoroethylene (PTFE), ethylene tetrafluoroethylene (ETFE), fluorinated ethylene propylene (FEP), perfluoroalkoxy (PFA), polychlorotrifluoroethylene (PCTFE), ethylene-chlorotrifluoroethylene copolymer (ECTFE), polyvinylidene fluoride (PVDF), polyvinylidene fluoride-hexafluoropropylene copolymer, or polyvinylidene fluoride-chlorotrifluoroethylene copolymer.The second binder consists of PVDF, carboxymethyl cellulose (CMC), polymerized styrene butadiene rubber (SBR), polyvinyl pyrrolidone (PVP), polymethyl methacrylate (PMMA), polyacrylonitrile (PAN), polyacrylic acid (PAA), polyurethane, polyvinyl alcohol (PVA), and sodium alginate. The binder is selected from at least one of the following: alginate (Alg), ethylene-propylene-diene monomer, styrene-butadiene rubber, fluororubber, β-cyclodextrin polymer (β-cyclodextrin, β-CDp), polypropylene emulsion (LA132), PTFE, ETFE, FEP, PFA, PCTFE, ECTFE, polyvinylidene fluoride-hexafluoropropylene copolymer, or vinylidene fluoride-chlorotrifluoroethylene copolymer. By adding a binder, the processability of the solid electrolyte membrane can be improved, volume expansion can be mitigated, the structure of the solid electrolyte membrane can be stabilized, and a self-supporting solid electrolyte membrane can be obtained.

[0027] The present invention further provides a method for preparing a solid electrolyte membrane. The preparation method used to prepare the above-mentioned solid electrolyte membrane includes at least the following: Based on the chemical formula of the sulfide solid electrolyte, raw materials are mixed and homogenized according to stoichiometry, then placed in a ball mill pot and ball-milled to obtain a sulfide solid electrolyte precursor powder. The sulfide solid electrolyte precursor powder is calcined at a predetermined temperature to obtain a sulfide solid electrolyte. The sulfide solid electrolyte and a binder are mixed, and a solid electrolyte membrane is obtained by a dry process or a wet process.

[0028] In one embodiment of the present invention, the chemical formula of the sulfide solid electrolyte is "Li f P 1-g E g Sw O g Q z Based on the above, the Li source, P source, E source, S source and Q source are mixed and homogenized according to stoichiometry. Here, the Li source is one or more selected from LiCl, LiBr, LiI or Li2S; the P source is one or more selected from monoplasmic P, P2S5, P4S6, PCl5 or PBr5, etc.; the E source is one or more selected from oxides of E or sulfides of E; the S source is one or more selected from monoplasmic S, Li2S, P2S5, P4S6, MgS, CaS, SrS, BaS, ZnS, CrS, SnS or PbS, etc.; the Q source is one or more selected from LiCl, PCl5, LiBr, PBr5, LiI or I2, etc.; and the O element in the chemical formula is derived from an oxide of E. After mixing and homogenizing the raw materials, they are placed in a ball mill pot and ball milling is performed under an inert atmosphere. Here, the ball-to-powder ratio is, for example, 1:1 to 100:1, the ball mill rotation speed is, for example, 50 to 1500 rpm, and the ball milling time is, for example, 1 to 48 hours, to obtain sulfide solid electrolyte precursor powder.

[0029] 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, thereby obtaining a sulfide solid electrolyte.

[0030] As shown in Figure 1, in one embodiment of the present invention, when a solid electrolyte membrane is prepared by a dry process, for example, a powder extrusion molding method is employed, and the binder is selected from the first binder. Specifically, the sulfide solid electrolyte and the first binder are mixed and homogenized, for example, by low-temperature shearing, and then the temperature is rapidly increased to perform high-temperature shearing mixing to obtain a mixed raw material. Furthermore, the mixed raw material is added to a roll mill and high-temperature roll rolling is performed to obtain a solid electrolyte membrane. Here, the mass ratio of the first binder to the sulfide solid electrolyte is, for example, 0.1:99.9 to 5:95, the low-temperature shearing temperature is, for example, -30 to 15°C, the high-temperature shearing temperature is, for example, 20 to 200°C, and the high-temperature roll rolling temperature is, for example, 20 to 200°C. In the dry process, the first binder surrounds the sulfide solid electrolyte in a mesh-like manner, which can improve the mechanical strength and chemical stability of the solid electrolyte membrane. During the battery charging and discharging process, stable contact between the electrolyte and electrode material can be maintained, thereby improving the battery's performance and lifespan.

[0031] In one embodiment of the present invention, when a solid electrolyte membrane is prepared by a wet process, for example, a wet coating method and an electrostatic spraying method are employed, and the binder is selected from a second binder. Specifically, the sulfide solid electrolyte, the second binder, and the solvent are mixed and homogenized to obtain an electrolyte slurry. The electrolyte slurry is then applied to a substrate by a wet coating method or an electrostatic spraying method, and subsequently the substrate to which the electrolyte slurry has been applied is dried and peeled to obtain a solid electrolyte membrane. Here, the solvent is selected from at least one of the following, for example, toluene, chlorobenzene, xylene, dimethyl carbonate, N-methylformamide, n-hexane, glycol dimethyl ether, dibutyl ether, ethanol, 1,2-ethylenediamine, 1,2-ethanedithiol, acetonitrile, tetrahydrofuran, methanol, isopropyl ether, acetone, hexene, ethyl acetate, benzyl acetate, butyl butyrate, or diisobutyl ketone. In the electrolyte slurry, the content of the sulfide solid electrolyte is, for example, 30 to 90% by mass, the content of the second binder is, for example, 0.1 to 10% by mass, and the content of the solvent is, for example, 10 to 50% by mass. After drying, the mass ratio of the second binder to the sulfide solid electrolyte is, for example, 0.1:30 to 10:90. The substrate is selected from, for example, polyethylene glycol terephthalate (PET) film, smooth aluminum foil, or release paper to facilitate demolding, and the drying temperature is, for example, 30 to 250°C.

[0032] The present invention also provides an all-solid-state lithium-ion battery comprising a positive electrode sheet, a negative electrode sheet, and a solid electrolyte membrane, the solid electrolyte membrane being placed between adjacent positive and negative electrode sheets. The solid electrolyte membrane is selected from the above-mentioned solid electrolyte membranes to improve the performance of the all-solid-state lithium-ion battery.

[0033] In one embodiment of the present invention, the positive electrode sheet comprises a positive electrode active material and a halide solid electrolyte. The positive electrode active material is 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 lithium-ion battery, and does not undergo an exothermic reaction with the lithium-ion cathode active material, thereby improving the safety of the lithium-ion battery. The cathode sheet further contains a conductive agent and a binder, the conductive agent being one or at least two of the following: conductive carbon black (Super P, SP), carbon nanotubes (CNT), vapor-grown carbon fiber (VGCF), or graphene. The binder is, for example, polytetrafluoroethylene (PTFE) and its derivatives.

[0034] In one embodiment of the present invention, 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. 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 a positive electrode sheet is obtained by dry pressing.

[0035] In one embodiment of the present invention, the negative electrode sheet is one or more of the following: metallic lithium foil, metallic indium foil, or lithium indium alloy foil. The negative electrode sheet includes, for example, a negative electrode active material, which is selected from one or more of the following: graphite-based materials, silicon materials, or composite materials of graphite-based materials and silicon materials. In one embodiment of the present invention, if the negative electrode sheet includes a negative electrode active material, the negative electrode sheet further includes a solid electrolyte, a conductive agent, and a binder. The solid electrolyte is, for example, a halide solid electrolyte or a sulfide electrolyte. The present invention is not specifically limited. The binder is at least one of the following: polyisoprene, polyethylene, or polypropylene. The conductive agent is at least one of the following: 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, which are selected based on manufacturing requirements. The negative electrode sheet is obtained, for example, by dry pressing.

[0036] In one embodiment of the present invention, the negative electrode sheet is selected as, for example, metallic lithium foil, and the positive electrode sheet, solid electrolyte membrane, and negative electrode sheet are sequentially laminated, sealed, hot-pressed, and cold-pressed. An aluminum plastic film or the like is then placed over the battery in a vacuum or inert atmosphere to obtain an all-solid-state pouch-type lithium-ion battery. The assembly process of the all-solid-state lithium-ion battery is completed, for example, in a glove box under an argon atmosphere.

[0037] The present invention will be described more specifically below with reference to the following embodiments, but these embodiments 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.

[0038] Example 1 Preparation of sulfide solid electrolytes: After obtaining a precursor powder by high-energy ball milling (ball-to-powder ratio of 30:1 and rotation speed of 500 rpm) of 2.03 mol of Li2S, 1.5 mol of LiCl, 0.49 mol of P2S5, and 0.02 mol of MgO, the precursor powder is sintered at 500°C for 10 hours. After cooling, Li5.56 P 0.98 Mg 0.02 S 4.48 O 0.02 Cl 1.5 A sulfide solid electrolyte represented by [formula] is obtained. Preparation of solid electrolyte membranes: Li, an electrolyte 5.56 P 0.98 Mg 0.02 S 4.48 O 0.02 Cl 1.5 The PTFE is uniformly mixed with the PTFE in a mass ratio of 99:1 at -20°C, and the temperature is raised to 80°C for further mixing to fibrousize the PTFE and obtain a mixed raw material. The mixed raw material is extruded into a roll press machine, and the solid electrolyte membrane is roll-pressed to a thickness of 5 μm at a temperature of 80°C by adjusting the gap of the roll press machine. Preparation of the positive electrode sheet: LiRing 0.8 Co 0.1 Mn 0.1 O2, conductive agent, Li 2.35 Zr 0.65 Fe 0.35 Cl5Br 0.5 I 0.5 The positive electrode sheet is prepared by a dry process using a mixture of PTFE and super-P in a mass ratio of 69:1:29:1. The conductive agents are super-P and VGCF in a mass ratio of 1:1. Negative electrode sheet: Select a metallic lithium piece for the negative electrode sheet. Assembly of all-solid-state batteries: The positive electrode sheet, solid electrolyte membrane, and negative electrode sheet prepared as described above are assembled into an all-solid-state pouch-type battery by lamination, sealing, hot pressing, and cold pressing processes. Assembling symmetric cells: Counter electrodes (Li) are placed on both sides of a solid electrolyte membrane, and the solid electrolyte membrane is assembled with these electrodes to form a Li / Li symmetric cell.

[0039] Example 2 The solid electrolyte membrane was fabricated in the same manner as in Example 1, except that the thickness was adjusted to 10 μm by adjusting the roll gap of the roll press machine.

[0040] Example 3 The solid electrolyte membrane was fabricated in the same manner as in Example 1, except that the thickness was adjusted to 30 μm by adjusting the roll gap of the roll press machine.

[0041] Example 4 The solid electrolyte membrane was fabricated in the same manner as in Example 1, except that the thickness was adjusted to 50 μm by adjusting the roll gap of the roll press machine.

[0042] Example 5 The solid electrolyte membrane was fabricated in the same manner as in Example 1, except that the thickness was adjusted to 100 μm by adjusting the roll gap of the roll press machine.

[0043] Example 6 The solid electrolyte membrane was fabricated in the same manner as in Example 1, except that the thickness was adjusted to 200 μm by adjusting the roll gap of the roll press machine.

[0044] Example 7 The chemical formula of the sulfide solid electrolyte prepared using 2.015 moles of Li2S, 1.5 moles of LiCl, 0.495 moles of P2S5, and 0.01 moles of MgO is Li 5.53 P 0.99 Mg 0.01 S 4.49 O 0.01 Cl 1.5 Except for the above, it was prepared in the same manner as in Example 3.

[0045] Example 8 The chemical formula of the sulfide solid electrolyte prepared using 2.0225 moles of Li2S, 1.5 moles of LiCl, 0.4925 moles of P2S5, and 0.015 moles of MgO is Li 5.545 P 0.985 Mg 0.015 S 4.485 O 0.015 Cl 1.5 Except for the above, it was prepared in the same manner as in Example 3.

[0046] Example 9 The chemical formula of the sulfide solid electrolyte prepared using 2.06 mol of Li2S, 1.5 mol of LiCl, 0.48 mol of P2S5, and 0.04 mol of MgO is Li 5.62 P 0.96 Mg 0.04 S 4.46 O 0.04 Cl 1.5 It was prepared in the same manner as in Example 3 except that it was set as such.

[0047] Example 10 The chemical formula of the sulfide solid electrolyte prepared using 2.09 mol of Li2S, 1.5 mol of LiCl, 0.47 mol of P2S5, and 0.06 mol of MgO is Li 5.68 P 0.94 Mg 0.06 S 4.44 O 0.06 Cl 1.5 It was prepared in the same manner as in Example 3 except that it was set as such.

[0048] Example 11 The chemical formula of the sulfide solid electrolyte prepared using 2.12 mol of Li2S, 1.5 mol of LiCl, 0.46 mol of P2S5, and 0.08 mol of MgO is Li 5.74 P 0.92 Mg 0.08 S 4.42 O 0.02 Cl 1.5 It was prepared in the same manner as in Example 3 except that it was set as such.

[0049] Example 12 The chemical formula of the sulfide solid electrolyte prepared using 2.15 mol of Li2S, 1.5 mol of LiCl, 0.45 mol of P2S5, and 0.1 mol of MgO is Li 5.8 P 0.9 Mg 0.1 S 4.48 O 0.1 Cl 1.5 It was prepared in the same manner as in Example 3 except that it was set as such.

[0050] Example 13 The sulfide solid electrolyte prepared using 1.83 mol of Li2S, 1.9 mol of LiCl, 0.49 mol of P2S5 and 0.02 mol of MgO has the chemical formula Li 5.16 P 0.98 Mg 0.02 S 4.08 O 0.02 Cl 1.9 and was prepared in the same manner as in Example 3, except for this.

[0051] Example 14 The sulfide solid electrolyte prepared using 2.53 mol of Li2S, 1 mol of LiCl, 0.49 mol of P2S5 and 0.02 mol of MgO has the chemical formula Li 6.06 P 0.98 Mg 0.02 S 4.98 O 0.02 Cl and was prepared in the same manner as in Example 3, except for this.

[0052] Example​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​The chemical formula of the sulfide solid electrolyte prepared using 2.03 moles of Li2S, 1.4 moles of LiCl, 0.1 moles of LiBr, 0.49 moles of P2S5, and 0.02 moles of MgO is Li 5.56 P 0.98 Mg 0.02 S 4.48 O 0.02 Cl 1.4 Br 0.1 Except for the above, it was prepared in the same manner as in Example 3.

[0055] Example 18 The chemical formula of the sulfide solid electrolyte prepared using 2.03 mol Li2S, 1.3 mol LiCl, 0.1 mol LiBr, 0.1 mol LiI, 0.49 mol P2S5, and 0.02 mol MgO is Li 5.56 P 0.98 Mg 0.02 S 4.48 O 0.02 Cl 1.3 Br 0.1 I 0.1 Except for the above, it was prepared in the same manner as in Example 3.

[0056] Example 19 The binder was prepared in the same manner as in Example 3, except that ETFE was selected.

[0057] Example 20 The binder was prepared in the same manner as in Example 3, except that PCTFE was selected.

[0058] Example 21 Preparation of sulfide solid electrolytes: After obtaining a precursor powder by high-energy ball milling (ball-to-powder ratio of 30:1 and rotation speed of 500 rpm) using 2.03 mol of Li2S, 1.5 mol of LiCl, 0.49 mol of P2S5, and 0.02 mol of MgO raw materials, the precursor powder is sintered at 500°C for 10 hours. After cooling, Li 5.56 P 0.98 Mg 0.02 S 4.48 O 0.02 Cl 1.5 A sulfide solid electrolyte represented by [formula] is obtained. Preparation of solid electrolyte membranes: Li 5.56 P 0.98 Mg 0.02 S 4.48 O 0.02 Cl 1.5 The SBR binder and xylene solvent are uniformly mixed in a mass ratio of 49:1:50 to prepare an electrolyte slurry. The electrolyte slurry is coated onto a smooth aluminum foil using a coater, vacuum-dried at 80°C, and peeled off to prepare a solid electrolyte film with a thickness of 30 μm. Preparation of the positive electrode sheet: LiRing 0.8 Co 0.1 Mn 0.1 O2, conductive agent, Li 2.35 Zr 0.65 Fe 0.35 Cl5Br 0.5 I 0.5 A positive electrode sheet is prepared by a dry process using a mixture of PTFE and super-P in a mass ratio of 69:1:29:1. Here, the conductive agents are super-P and VGCF in a mass ratio of 1:1. Negative electrode sheet: Select a metallic lithium piece for the negative electrode sheet. Assembly of all-solid-state batteries: The positive electrode sheet, solid electrolyte membrane, and negative electrode sheet prepared above are assembled into an all-solid-state pouch-type battery through lamination, sealing, hot-pressing, and cold-pressing processes. Assembling symmetric cells: Counter electrodes (Li) are placed on both sides of a solid electrolyte membrane, and the solid electrolyte membrane is assembled with these electrodes to form a Li / Li symmetric cell.

[0059] Example 22 The binder was prepared in the same manner as in Example 21, except that PVDF was selected.

[0060] Example 23 The binder was prepared in the same manner as in Example 21, except that PAA was selected.

[0061] Example 24 The chemical formula of the sulfide solid electrolyte prepared using 2.03 moles of Li2S, 1.5 moles of LiCl, 0.49 moles of P2S5, and 0.02 moles of CaO is Li 5.56 P 0.98 Ca 0.02 S 4.48 O 0.02 Cl 1.5 Except for the above, it was prepared in the same manner as in Example 3.

[0062] Example 25 The chemical formula of the sulfide solid electrolyte prepared using 2.03 moles of Li2S, 1.5 moles of LiCl, 0.49 moles of P2S5, and 0.02 moles of ZnO is Li 5.56 P 0.98 Zn 0.02 S 4.48 O 0.02 Cl 1.5 Except for the above, it was prepared in the same manner as in Example 3.

[0063] Comparative Example 1 The chemical formula of the 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 Except for the above, it was prepared in the same manner as in Example 3.

[0064] 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 Except for the above, it was prepared in the same manner as in Example 3.

[0065] 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 0.1Except for the above, it was prepared in the same manner as in Example 3.

[0066] Comparative Example 4 The solid electrolyte membrane was fabricated in the same manner as in Example 3, except that the thickness was adjusted to 1 μm by adjusting the gap between the rolls of the roll rolling mill.

[0067] In Examples 1 to 25 and Comparative Examples 1 to 4 of the present invention, different solid electrolyte membranes are used, and the ionic conductivity of the solid electrolyte membranes is measured. After leaving the solid electrolyte membranes in a drying room at -40°C for 24 hours, the ionic conductivity is measured again. In these examples, the ionic conductivity is obtained, for example, by the AC impedance method, and the measurement results are shown in Table 1.

[0068] In this invention, lithium-ion batteries are obtained by employing different sulfide solid electrolytes in Examples 1 to 25 and Comparative Examples 1 to 4. Long-cycle charge-discharge is performed on the lithium-ion batteries prepared above under a 25°C environment, the discharge capacity is measured, and the energy density is calculated. Here, the operating voltage range for battery measurement is 2.5 to 4.3V, the charge-discharge ratio is 1C / 1C, the discharge capacity of the first cycle is recorded and taken as the 1C discharge capacity, and the measurement is terminated when the battery capacity reaches 80% of the first cycle capacity (80% State of Health, 80% SOH), and the number of cycles at room temperature is obtained. Symmetric cell is measured at 1 mA / cm 2 A constant current charge-discharge cycle test was conducted under the specified current density, and the measurement results are shown in Table 2.

[0069] Table 1 shows the ionic conductivity of sulfide solid electrolytes for Examples 1-25 and Comparative Examples 1-4.

[0070] Table 2 shows the measurement results for lithium-ion batteries and symmetrical cells in Examples 1-25 and Comparative Examples 1-4.

[0071] [Table 1]

[0072] [Table 2]

[0073] Please refer to Tables 1 and 2. As can be seen from the comparison between Examples 1-6 and Comparative Example 4, as the thickness of the solid electrolyte membrane increases, the retention rate of the ion conductivity of the solid electrolyte membrane at low temperatures increases, and the cycle performance of the lithium-ion battery increases gradually first, and then decreases gradually. Furthermore, when the solid electrolyte membrane was excessively thin, a battery short circuit was detected at a relatively low number of cycles. Therefore, considering both the retention rate of ion conductivity and cycle performance simultaneously, there is an optimal range for the thickness of the solid electrolyte membrane.

[0074] Please refer to Tables 1 and 2. As can be seen from the comparison of Examples 3, 7-12, when Mg is selected as the E element in the sulfide solid electrolyte, the cycle performance of the lithium-ion battery increases and decreases in stages as the amount of Mg doping increases. In addition, as the amount of E element doping increases, the ionic conductivity of the solid electrolyte membrane decreases, but the retention rate of ionic conductivity after 24 hours of exposure in a -40°C drying chamber increases, enhancing the air stability and chemical stability of the solid electrolyte membrane, and improving the stability and performance of the battery. This indicates that appropriate doping of the E element promotes the formation of a stable solid electrolyte interface (SEI) and reduces side reactions between the solid electrolyte and electrode material. If the doping amount is too low, it may not be possible to form an effective SEI membrane. Excessive doping causes excessive lattice strain and destroys the existing crystal structure, reducing the structural stability of the material and potentially leading to phase separation and amorphous phenomena. This reduces the ionic conductivity of the material. Therefore, by controlling the amount of E element doping in the sulfide solid electrolyte, it is possible to improve the cycle life and safety of all-solid-state lithium-ion batteries while simultaneously maintaining a relatively high level of ionic conductivity, ensuring the rate performance of lithium-ion batteries, and improving charge / discharge efficiency and cycle life.

[0075] Please refer to Figure 2. In the room-temperature cycling process of the all-solid-state lithium-ion battery in Example 3, the current density used for constant current charging and discharging was 1C. As can be seen from Figure 2, at a current density of 1C, the all-solid-state lithium-ion battery in Example 3 still has a capacity of approximately 140 mAh / g even after 500 cycles, demonstrating that the sulfide solid electrolyte has excellent reaction kinetics and cycle stability. The obtained solid electrolyte membrane has a good effect on the battery's cycle stability and reaction activity ratio capacity, and the all-solid-state lithium-ion battery simultaneously satisfies excellent performance requirements such as ratio capacity, rate performance, and cycle life.

[0076] Please refer to Tables 1 and 2. As can be seen from the comparison of Examples 3, 13-16, when the amount of Mg doping is the same, increasing or decreasing the Cl content significantly reduces the ionic conductivity, and in both cases, it reduces the cycle performance of the lithium-ion battery. Therefore, by controlling the Cl content, it is possible to ensure the ionic conductivity of the sulfide solid electrolyte and the performance of the lithium-ion battery.

[0077] Refer to Tables 1 and 2. As can be seen from the comparison of Examples 3, 17-18, when the amount of Mg doping is the same, doping with one or more elements of Br or I reduces the battery's cycle performance. This is because doped Br or I may introduce additional lattice defects, and these defects may hinder lithium ion conduction, further reducing the ionic conductivity of the electrolyte. Therefore, by selecting Cl as Q, the ionic conductivity and electrochemical stability of the sulfide solid electrolyte can be improved, and voltage stability can be enhanced.

[0078] Please refer to Tables 1 and 2. As can be seen from the comparison of Examples 3, 17-18 and Comparative Examples 1-3, when elements E and O are not added to the sulfide solid electrolyte, lithium-ion batteries have almost no cycle performance and short circuits occur in a short time. This explains that when elements E and O are deficient, the chemical stability of the sulfide solid electrolyte material is poor, resulting in insufficient mechanical strength and making it difficult to guarantee the long-term cycle performance of lithium-ion batteries. By introducing elements E and O, the cycle performance of lithium-ion batteries can be improved. As can be seen from the comparison of Examples 3, 24-25, even when other elements are selected as the doping element as E, the ionic conductivity retention rate can be increased, the stability of the sulfide solid electrolyte can be improved, and the cycle performance of lithium-ion batteries can be improved, but it is inferior to Mg doping, so Mg doping is optimal for lithium-ion battery performance.

[0079] Please refer to Tables 1 and 2. As can be seen from the comparison of Examples 3 and 19-20, in the dry process, the ionic conductivity of the solid electrolyte membrane and the performance of the lithium-ion battery are affected when a different first binder is selected. Here, when PTFE is selected as the first binder, the ionic conductivity of the solid electrolyte membrane and the performance of the lithium-ion battery are optimal. As can be seen from the comparison of Examples 21-23, in the wet process, the ionic conductivity of the solid electrolyte membrane and the performance of the lithium-ion battery are affected when a different second binder is selected. Here, when PAA is selected as the second binder, the ionic conductivity of the solid electrolyte membrane and the performance of the lithium-ion battery are optimal. As can be seen from the comparison of Examples 3 and 21, solid electrolyte membranes prepared by the dry process have better performance than solid electrolyte membranes prepared by the wet process. This is because the wet process uses a large amount of organic solvent, which undergoes a minor reaction with the electrolyte, thereby reducing the performance of the electrolyte membrane, whereas the dry process does not involve the introduction of solvent.

[0080] The present invention further provides electronic devices, each comprising at least one of the above-described 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 aircraft, 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 aircraft 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 electric drills, concrete vibrators, and electric planers, etc. Since the electronic devices include the above-described lithium-ion batteries, they include the above-described advantages of lithium-ion batteries, which are not described in detail here.

[0081] As described above, the present invention provides a solid electrolyte membrane, a method for preparing the same, and its applications. By introducing elements E, O, and Q into the sulfide solid electrolyte within the solid electrolyte membrane, the air stability of the solid electrolyte membrane is effectively improved, reducing H2S gas generated by atmospheric degradation, and enhancing the air and chemical stability of the solid electrolyte membrane. A special interfacial layer can be formed at the electrolyte / lithium metal anode interface, ensuring the ionic conductivity of the solid electrolyte membrane and promoting high-speed lithium ion movement and uniform electric field distribution. This contributes to controlling lithium nucleation and growth and preventing the formation of lithium dendritic crystals. This significantly improves the stability and performance of lithium-ion batteries, enhances the lifespan and safety of lithium batteries in all-solid-state lithium-ion batteries, and improves the compatibility between the solid electrolyte membrane and the active material.

[0082] The above description is merely a description of preferred embodiments and the technical principles in which the present invention is applied. 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 arbitrarily combining 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] The solid electrolyte membrane of the present invention can be applied to all-solid-state lithium-ion batteries and electronic devices.

Claims

1. at least, Binder and, A solid electrolyte membrane comprising a sulfide solid electrolyte, The chemical formula of the sulfide solid electrolyte is Li ｆ P １－ｇ E ｇ S ｗ O ｇ Q ｚ And, In the formula, 5 < f < 10, 0 < g < 1, 3 < w < 6, 4 < w + g < 6, 0 < z < 2, E is one or more selected from Mg, Ca, Sr, Ba, Zn, Cr, Sn or Pb, and Q is one or more selected from Cl, Br or I. Ionic conductivity is 1 × 10⁻⁶ －３ ~2 x 10 －２ It is S / cm, The thickness of the solid electrolyte membrane is 5 to 200 μm. A solid electrolyte membrane characterized by the following features.

2. E is Mg. The solid electrolyte membrane according to claim 1, characterized in that...

3. Q is Cl, and the acceptable range for g is 0.01 ≤ g ≤ 0.

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

4. The mass ratio of the binder to the sulfide solid electrolyte is 0.1:99.9 to 10:

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

5. A method for preparing a solid electrolyte membrane according to any one of claims 1 to 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 using a ball mill 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, This includes mixing the sulfide solid electrolyte with a binder and obtaining the solid electrolyte film by a dry or wet process. A method for preparing a solid electrolyte membrane, characterized by the following features.

6. The Li source is one or more selected from LiCl, LiBr, LiI, or Li ２ S, and The aforementioned P source is a single P, P ２ S ５ , P ４ S ６ , PCL ５ , or PBr ５ One or more selected from, The aforementioned E source is one or more selected from oxides of E or sulfides of E. The aforementioned S source is a single S, Li ２ S, P ２ S ５ , P ４ S ６ , one or more selected from MgS, CaS, SrS, BaS, ZnS, CrS, SnS, or PbS, The aforementioned Q source is LiCl, PCL ５ LiBr, PBr ５ , LiI, or I ２ One or more selected from, The element O in the chemical formula is derived from an oxide of E. A method for preparing a solid electrolyte membrane according to claim 5, characterized in that...

7. When the solid electrolyte membrane is prepared by a dry process, the binder is selected from the first binder. The first binder is one or more selected from polytetrafluoroethylene, ethylene-tetrafluoroethylene copolymer, fluorinated ethylene propylene copolymer, perfluoroalkoxy resin, polychlorotrifluoroethylene, ethylene-chlorotrifluoroethylene copolymer, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, or polyvinylidene fluoride-chlorotrifluoroethylene copolymer. A method for preparing a solid electrolyte membrane according to claim 5, characterized in that...

8. When the solid electrolyte membrane is prepared by a wet process, the binder is selected from the second binder. The second binder is one or more selected from polyvinylidene fluoride, carboxymethylcellulose, styrene-butadiene rubber, polyvinylpyrrolidone, polymethyl methacrylate, polyacrylonitrile, polyacrylic acid, polyurethane, polyvinyl alcohol, sodium alginate, ethylene-propylene-diene monomer, styrene-butadiene rubber, fluororubber, β-cyclodextrin polymer, polypropylene emulsion, polytetrafluoroethylene, ethylene-tetrafluoroethylene copolymer, fluorinated ethylene-propylene copolymer, perfluoroalkoxy resin, polychlorotrifluoroethylene, ethylene-chlorotrifluoroethylene copolymer, polyvinylidene fluoride-hexafluoropropylene copolymer, or polyvinylidene fluoride-chlorotrifluoroethylene copolymer. A method for preparing a solid electrolyte membrane according to claim 5, characterized in that...

9. 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 The solid electrolyte membrane is installed between adjacent positive electrode sheets and negative electrode sheets and is selected from the solid electrolyte membranes described in any one of claims 1 to 4, and includes at least one of these. A solid-state lithium-ion battery characterized by the following features.

10. Includes the all-solid-state lithium-ion battery described in claim 9. An electronic device characterized by the following features.

Images