Roll-to-roll formation method of solid electrolyte using metal colloidal particles

Abstract

The present invention relates to a roll-to-roll forming method of a solid electrolyte using metal colloid particles, and more specifically, to a roll-to-roll forming method of a solid electrolyte using metal colloid particles, wherein a solid electrolyte material of a desired composition is designed by directly coating the metal colloid particles on a metal electrode foil, and a roll-to-roll-based sulfidation reaction is sequentially induced on the solid electrolyte forming layer without going through a complicated powder processing process, thereby being able to form a void-free sulfide-based solid electrolyte material.

Description

Technical Field

[0001] The present invention relates to a roll-to-roll formation method of a solid electrolyte using metal colloidal particles, and more specifically, to a method for forming a sulfide-based solid electrolyte by coating metal colloidal particles on a metal electrode foil (positive electrode plate or negative electrode plate) and sequentially inducing a sulfidation reaction based on a roll-to-roll method. Background Art

[0002] A secondary battery is a battery that can be used semi-permanently by repeatedly charging and discharging. It refers to a device that converts external electrical energy into chemical energy for storage and generates electricity when needed. The four core materials of a secondary battery are positive electrode material, negative electrode material, separator and electrolyte.

[0003] Lithium-ion batteries are representative secondary batteries that have the advantages of being smaller in weight and volume than other batteries of the same capacity, and having higher output than ordinary batteries. Lithium-ion batteries are rapidly developing from the small battery market to the electric vehicle and large and medium-sized markets, and are applicable as core technologies for future industries, and have the potential to expand to various industries.

[0004] However, lithium ion batteries, as a common secondary battery, have various problems in battery stability such as leakage, impact, fire, and explosion due to the use of organic solvents, because they use liquid electrolytes containing organic solvents.

[0005] Based on this, all-solid batteries that use solid electrolytes to replace the liquid electrolytes in the components of traditional lithium-ion batteries have attracted attention as the next generation of secondary batteries. Since all-solid-state batteries use solid electrolytes, the risk of fire and explosion is significantly reduced, so they have the following advantages: a wide range of battery applications, a simplified manufacturing process, and high energy density.

[0006] Conventional all-solid-state batteries have the following problems: in order to form a solid electrolyte, which is a core component of an all-solid-state battery, a complicated process is required, such as synthesizing sulfide powder of a desired composition, coating electrodes, rolling, and heat treatment.

[0007] In particular, there are the following disadvantages: 1) it is difficult to densify pre-synthesized ceramic particles without voids in the process of densifying sulfide powder, and 2) it is difficult for the pre-synthesized ceramic particles to form a homogeneous interface with particles constituting the positive and negative electrodes.

[0008] Prior art literature

[0009] Korean Patent No. 10-2088648

[0010] Korean Patent No. 10-2193945 Summary of the invention

[0011] Problem that the invention aims to solve

[0012] The object of the present invention is to provide a roll-to-roll formation method of a solid electrolyte using metal colloid particles, wherein a solid electrolyte material of a desired composition is designed by directly coating the metal colloid particles on a metal electrode foil (Foil), and a sequential sulfidation reaction based on a roll-to-roll method is induced without the need for a complicated powder processing process, thereby being able to form a void-free sulfide-based solid electrolyte material.

[0013] Means used to solve problems

[0014] In order to achieve the above object, the present invention provides a roll-to-roll forming method of a solid electrolyte using metal colloid particles, characterized in that it comprises the following steps:

[0015] Step a, forming a solid electrolyte layer by directly coating metal colloidal particles on a metal electrode foil;

[0016] Step b is a step of supplying a sulfur source to the solid electrolyte layer formed in step a to induce a sulfurization reaction, thereby forming a sulfide-based solid electrolyte layer.

[0017] In the direct coating step of forming the solid electrolyte layer, the metal colloid particles can be in a colloidal form consisting of at least one alloy metal particle selected from the group consisting of single metal particles of copper (Cu), lithium (Li), germanium (Ge), phosphorus (P), silicon (Si), sodium (Na), molybdenum (Mo), lanthanum (La), zirconium (Zr) and combinations thereof.

[0018] In the step of forming the sulfide-based solid electrolyte layer by inducing the sulfidation reaction, the supplied sulfur source includes at least one of hydrogen sulfide (H2S), sulfur gas (S Vapor) and methyl mercaptan (CH3SH), and the supply can be achieved by continuous or pulse supply of gas.

[0019] Effects of the Invention

[0020] In a roll-to-roll formation method of a solid electrolyte using metal colloid particles according to one embodiment of the present invention, single metal colloid particles such as copper and lithium or metal alloy colloid particles are directly coated on a metal electrode foil, thereby designing a solid electrolyte material of a desired composition.

[0021] Furthermore, a sulfidation reaction is sequentially induced to the solid electrolyte forming layer on a roll-to-roll basis without a complicated powder processing process, thereby being able to form a void-free sulfide-based solid electrolyte material. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 4 is a flow chart of a roll-to-roll forming method of a solid electrolyte using metal colloidal particles according to an embodiment of the present invention.

[0023] Figure 2 FIG. 1 is a diagram showing a process of directly coating a metal electrode foil with metal colloidal particles according to an embodiment of the present invention.

[0024] Figure 3 FIG. 1 is a diagram showing a process of inducing a sequential sulfurization reaction by supplying a sulfur source to a solid electrolyte-forming layer coated on a metal electrode foil according to an embodiment of the present invention. DETAILED DESCRIPTION

[0025] Hereinafter, the present invention will be described in more detail.

[0026] One embodiment of the present invention relates to a roll-to-roll forming method of a solid electrolyte using metal colloidal particles, characterized in that it comprises the following steps:

[0027] A step of forming a solid electrolyte layer by directly coating metal colloidal particles on a metal electrode foil (eg, step a);

[0028] A step of supplying a sulfur source to the solid electrolyte layer formed in the above step to induce a sulfurization reaction, thereby forming a sulfide-based solid electrolyte layer (eg, step b).

[0029] Specifically, the method of the present invention is to form a solid electrolyte layer by directly coating metal colloid particles on an electrode, and to sequentially supply a sulfur source on a roll-to-roll basis after directly coating the metal colloid on the electrode, thereby preparing a sulfide-based solid electrolyte. Furthermore, voids at the electrode-metal particle interface or voids that may occur between metal particles can be minimized.

[0030] The roll-to-roll method refers to coating, applying or printing a material while the material is being wound on a rotating roll in an electrode process. According to the roll-to-roll method, the material is transferred from one roll to the other roll by rotating a pair of rolls spaced a predetermined distance apart from each other.

[0031] This roll-to-roll technology has become increasingly important in the secondary battery industry due to its advantages of being suitable for large-area applications and simplified processes. The present invention is to form a sulfide-based solid electrolyte with minimized voids by coating metal colloid particles on an electrode through a sequential process based on the roll-to-roll method and sequentially supplying a sulfur source to the coated metal colloid solid electrolyte formation layer.

[0032] Reference Figure 2In the above step a, a particle supply unit 300 for supplying the metal colloidal particles to one side of the roller pair 210, 220 for conveying the metal electrode foil 100 may be provided at a position spaced apart from one side of the roller pair 210, 220. Figure 2 The particle supply unit 300 may be provided near the right roller 210 of the roller pair 210 and 220 shown in FIG. Figure 2 The right side roller in the middle may refer to the roller that starts to convey the metal electrode foil 100, and the roller on the other side (i.e. Figure 2 The left side roller in the middle) may refer to a roller at which the conveyance of the metal electrode foil 100 ends. In other words, the metal electrode foil 100 may be conveyed from a roller on one side of the roller pair 210, 220 spaced apart from each other to a roller on the other side.

[0033] In step a, the metal colloidal particles supplied by the particle supplying unit 300 can be applied to the metal electrode foil 100 passing through one side of the roller pair. In other words, the metal colloidal particles can be applied to the metal electrode foil 100 passing through one side of the roller pair through the particle supplying unit 300. Figure 2 The metal colloidal particles are supplied to the right roller in the middle, and the metal colloidal particles are applied to the portion of the metal electrode foil passing through one side of the roller pair, thereby forming a solid electrolyte layer.

[0034] In the above step b, when the metal electrode foil 100 is conveyed in a roll-to-roll manner, the sulfur source may be sequentially supplied along the length direction of the metal electrode foil 100. Specifically, the sulfur source supply unit 400 for supplying the sulfur source may be disposed on the upper side of the conveyed metal electrode foil 100 (i.e., the solid electrolyte layer on the metal electrode foil) and spaced apart therefrom. In other words, Figure 2 As shown, the sulfur source supplier 400 may be disposed in a direction perpendicular to the direction in which the roller pairs are spaced apart from each other. At this time, the sulfur source supplier 400 may be disposed above an imaginary line connecting the roller pairs and spaced apart therefrom.

[0035] Furthermore, the sulfur source may be sprayed downward from the sulfur source supply unit 400. In other words, the metal electrode foil (i.e., the metal electrode foil having the solid electrolyte layer formed thereon) continuously moving between the roller pairs 210 and 220 may pass under the sulfur source supply unit 400. At this time, the sulfur source may be continuously sprayed toward the metal electrode foil 100 passing under the sulfur source supply unit 400.

[0036] More specifically, in the metal electrode foil 100 coated with metal colloidal particles to form a solid electrolyte layer, in step b, the sulfur source can be sprayed onto the solid electrolyte layer on the metal electrode foil 100 by the sulfur source supply unit 400 during the process of being transferred from one side of the roller pair 210, 220 to the other side.

[0037] Furthermore, the above step a and step b may be performed sequentially and continuously.

[0038] As the metal colloid of the present invention, the colloidal electrolyte with a single metal particle or metal alloy particle introduced has the advantage of being able to directly control the physical properties of the interface, so it has the advantage of being able to simplify the design of solid electrolytes. Solid electrolytes are divided into organic (polymer) electrolytes and inorganic electrolytes. Colloidal electrolytes such as the metal colloid of the present invention can be classified as inorganic electrolytes.

[0039] The metal colloidal particles may be in a colloidal form consisting of at least one alloy metal particle selected from the group consisting of single metal particles of copper (Cu), lithium (Li), germanium (Ge), phosphorus (P), silicon (Si), sodium (Na), molybdenum (Mo), lanthanum (La), zirconium (Zr), and combinations thereof.

[0040] For the purpose of ensuring dispersibility and doping, the metal colloidal particles may contain chlorine (Cl), magnesium (Mg), sodium (Na), etc., and may be used together with molecules of polyethylene oxide (PEO), polyacrylonitrile (PAN), polyvinylidene difluoride (PVDF), polymethyl methacrylate (PMMA), etc., but are not limited thereto.

[0041] Dispersants that can be used to form the colloidal electrolyte may include a single solvent of fluoroethylene carbonate (FEC), polyethylene glycol (PEG), dimethylsulfoxide (DMSO), ethylene carbonate (EC), propylene carbonate (PC), diethyl carbonate (DEC), or dimethyl carbonate (DMC), or a mixture thereof, and are not limited thereto.

[0042] In one embodiment of the present invention, the sulfur source is characterized in that it includes at least one of hydrogen sulfide (H2S), sulfur gas (S Vapor) and methyl mercaptan (CH3SH), and can be supplied by continuous or pulse supply of gas. In the solid electrolyte layer formed by directly coating metal colloidal particles on a metal electrode foil, the sulfur source is supplied by sequentially supplying or pulse supplying gas to induce a sulfidation reaction, thereby forming a sulfide-based solid electrolyte.

[0043] In one embodiment of the present invention, the sulfur source may include thiol-containing molecules containing thiol groups.

[0044] In one embodiment of the present invention, when the sulfur source is supplied, the metal electrode foil may be heated at room temperature to 500° C. depending on the type of metal colloid. The metal electrode foil may be preheated by a separate heating element or may be heated by one roller of a heating roller pair.

[0045] A sulfur source is provided to the metal colloidal solid electrolyte layer directly coated on the metal electrode foil, thereby inducing a sulfurization reaction without the trouble of once synthesizing a sulfide powder of a desired composition and coating it on the electrode as in the prior art, or using a process such as high-energy ball milling to ensure the composition and crystallinity of the sulfide powder, or a complicated process such as rolling and heat treatment for forming a solid electrolyte.

[0046] Although the specific details of the present invention have been described in detail above, this specific description is only a preferred embodiment, and the scope of the present invention is not limited thereto, which is clear to those skilled in the art. As long as one is skilled in the art, various applications and modifications can be made within the scope of the present invention based on the content.

[0047] Accordingly, the true scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A roll-to-roll forming method of a solid electrolyte using metal colloidal particles, characterized in that: include: Step a, forming a solid electrolyte layer by directly coating metal colloidal particles on a metal electrode foil; step b, inducing a sulfurization reaction by supplying a sulfur source to the solid electrolyte layer formed in step a, thereby forming a sulfide-based solid electrolyte layer, The metal colloidal particles are in the form of colloids composed of at least one of single metal particles selected from copper, lithium, germanium, phosphorus, silicon, sodium, molybdenum, lanthanum, zirconium and alloy metal particles thereof. The alloy metal particles are selected from the group consisting of copper, lithium, germanium, phosphorus, silicon, sodium, molybdenum, lanthanum and zirconium. The supplied sulfur source includes at least one of hydrogen sulfide, sulfur gas and methyl mercaptan.

2. The roll-to-roll forming method of a solid electrolyte using metal colloid particles according to claim 1, characterized in that: The sulfur source is supplied by continuous or pulsed supply of gas.

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