Method for producing oxide-based solid electrolyte powder

Abstract

The present invention relates to a method for producing an oxide-based solid electrolyte powder, and the method for producing an oxide-based solid electrolyte powder according to one embodiment of the present invention includes the steps of vibrating a precursor aqueous solution containing Li2CO3, H3BO3, Al2O3, and LiCl to generate fine droplets, spraying the fine droplets, heating the sprayed fine droplets to generate powder, and collecting the generated powder.

Description

[Technical Field]

[0001] The present invention relates to a method for producing an oxide-based solid electrolyte powder. [Background technology]

[0002] Recently, the use of secondary batteries has increased significantly in various fields, from IT devices such as mobile phones to electric vehicles and energy storage devices.

[0003] Lithium-ion batteries, which use liquid electrolytes, are the most widely used secondary batteries. However, liquid electrolytes pose a risk of leakage if the battery is subjected to external impact, and as a result, additional parts and devices are required to ensure safety.

[0004] Recently, in order to improve the safety of secondary batteries, active development has been underway on all-solid-state batteries that use solid electrolytes. Solid electrolytes for all-solid-state batteries include polymer electrolytes, oxide electrolytes, and sulfide electrolytes. Of these, sulfide-based solid electrolytes have the highest ionic conductivity but have the problem of generating hydrogen sulfide gas when reacting with water. Polymer electrolytes have the advantage of being relatively simple to process and can be used in existing lithium-ion battery processes, but have the disadvantage of significantly lower ionic conductivity.

[0005] Oxide-based electrolytes have the advantage of being safer than sulfide-based electrolytes, but have relatively low ionic conductivity. Therefore, there is a need for technology to improve the ionic conductivity of oxide-based solid electrolytes for use in all-solid-state batteries.

[0006] Meanwhile, all-solid-state batteries can be used as batteries for small electronic devices. In order for all-solid-state batteries to be used in small electronic devices, they must also be implemented in a small size, which requires improving the energy density and increasing the battery capacity. Recently, as electronic devices have become increasingly miniaturized, the demand for increasing the capacity of all-solid-state batteries has also increased. Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention has been made to solve the above-mentioned problems of the prior art, and an object of the present invention is to provide a method for producing an oxide-based solid electrolyte powder that can improve the capacity of an all-solid-state battery.

[0008] Another object of the present invention is to provide a method for producing an oxide-based solid electrolyte powder that can improve the ionic conductivity of the oxide-based solid electrolyte. [Means for solving the problem]

[0009] A typical configuration of the present invention to achieve the above object is as follows.

[0010] A method for manufacturing an oxide-based solid electrolyte powder according to an embodiment of the present invention includes the steps of vibrating a precursor aqueous solution containing Li2CO3, H3BO3, Al2O3, and LiCl to generate fine droplets, spraying the fine droplets, heating the sprayed fine droplets to generate powder, and collecting the generated powder.

[0011] According to an embodiment of the present invention, in the spraying of the fine droplets, the fine droplets may be sprayed into a tube furnace.

[0012] According to an embodiment of the present invention, in the step of producing the powder, the sprayed fine droplets may be heated to a temperature of 1,000° C. or more.

[0013] According to an embodiment of the present invention, in the step of collecting the powder, the powder may be collected through at least one of a bag filter and a cyclon.

[0014] The D50 of the powder produced by the method according to one embodiment of the present invention may be 2.0 μm or less.

[0015] In addition, the oxide-based solid electrolyte powder manufactured according to an embodiment of the present invention may further include other additional components within a scope that does not detract from the technical spirit of the present invention. [Effects of the Invention]

[0016] According to an embodiment of the present invention, since the particle size of the oxide-based solid electrolyte powder can be made small, the capacity of the all-solid-state battery can be increased by stacking more electrolyte layers within the same volume of the all-solid-state battery.

[0017] Furthermore, according to an embodiment of the present invention, since the oxide-based solid electrolyte powder has a uniform particle size, it is possible to improve the sintering density and the ionic conductivity of the solid electrolyte. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a diagram schematically illustrating the configuration of an apparatus for manufacturing oxide-based solid electrolyte powder according to an embodiment of the present invention. [Figure 2] 2 is an operational flowchart illustrating an example of a process for manufacturing an oxide-based solid electrolyte powder according to an embodiment of the present invention. [Figure 3] 1 is an electron microscope image showing the appearance of oxide-based solid electrolyte powders according to an example of the present invention and a comparative example. [Figure 4] 1 is an electron microscope image showing the appearance of oxide-based solid electrolyte powders according to an example of the present invention and a comparative example after sintering. [Figure 5] 1 is a diagram schematically illustrating a cross-sectional structure of an all-solid-state battery manufactured using an oxide-based solid electrolyte powder according to an example of the present invention and a comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings. Hereinafter, a detailed description of publicly known functions and configurations will be omitted if it is determined that such description may unnecessarily obscure the gist of the present invention. It should be understood that the content described below is merely one embodiment of the present invention, and the present invention is not limited thereto.

[0020] The terms used in the present invention are merely used to describe specific embodiments and are not intended to limit the present invention. For example, elements expressed in the singular should be understood as including a plurality of elements unless the context clearly indicates that only the singular element is intended.

[0021] As used herein, expressions such as "comprises" should be understood as open-ended terms that include the possibility of including other embodiments, unless otherwise stated in the phrase or sentence that includes the expression.

[0022] The size, thickness, position, etc. of each component shown in the drawings are shown arbitrarily for the convenience of explanation, and the present invention is not necessarily limited to those shown in the drawings. In other words, it should be understood that the specific shapes, structures, and characteristics described in the specification may be changed and embodied from one embodiment to another without departing from the spirit and scope of the present invention, and the position or arrangement of individual components may also be changed without departing from the spirit and scope of the present invention.

[0023] Furthermore, unless otherwise defined, all terms used in the present invention, including technical or scientific terms, have the same meaning as commonly understood by a person of ordinary skill in the art to which the present invention belongs. Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with the contextual meaning of the relevant art, and should not be interpreted in an excessively restrictive or expansive manner unless otherwise clearly defined in the present invention.

[0024] Generally, an all-solid-state battery includes a positive electrode, a negative electrode, and a solid electrolyte layer. The solid electrolyte layer is disposed between the positive electrode and the negative electrode and can be in contact with the positive electrode and the negative electrode, respectively. The positive electrode and the negative electrode can include a positive electrode active material layer and a negative electrode active material layer, respectively, and the positive electrode active material layer and the negative electrode active material layer can be in contact with the solid electrolyte layer, respectively. The positive electrode and the negative electrode can be bonded to the solid electrolyte layer by sintering. That is, the positive electrode, the negative electrode, and the solid electrolyte layer can be sintered together.

[0025] The all-solid-state battery may be configured such that each of the positive electrode, negative electrode, and solid electrolyte layer is composed of a plurality of layers, or may be configured as a so-called stacked all-solid-state battery in which a plurality of positive electrodes, negative electrodes, and solid electrolyte layers are alternately stacked.

[0026] A solid electrolyte for an all-solid-state battery according to an embodiment of the present invention may have a boron oxide crystal structure such as boracite. In one embodiment, the solid electrolyte for an all-solid-state battery may be composed of an oxide having a composition system of Li-B-Al-O-Cl. For example, the solid electrolyte for an all-solid-state battery may include Li2O, BO3, Al2O3, and LiCl.

[0027] FIG. 1 is a diagram showing a schematic configuration of an apparatus for manufacturing an oxide-based solid electrolyte powder according to an embodiment of the present invention, and FIG. 2 is an operational flowchart showing an example of a process for manufacturing an oxide-based solid electrolyte powder according to an embodiment of the present invention. Hereinafter, the method for manufacturing an oxide-based solid electrolyte powder according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2.

[0028] According to one embodiment of the present invention, an oxide-based solid electrolyte powder can be produced by generating fine droplets of a precursor aqueous solution (S201), spraying the fine droplets (S203), heating the sprayed fine droplets (S205), and collecting the generated oxide solid electrolyte powder (S207).

[0029] First, in step S201, an aqueous precursor solution is vibrated to generate fine droplets. Here, the aqueous precursor solution may contain Li2CO3, H3BO3, Al2O3, and LiCl. Referring to FIG. 1, to generate fine droplets, the aqueous precursor solution may be introduced into a vibrating device 105 through an input pipe 101. At this time, a carrier gas may also be introduced into the vibrating device 105 through an input valve 103. Thereafter, the aqueous precursor solution may be vibrated within the vibrating device 105 to generate fine droplets of the aqueous precursor solution. In one embodiment, the vibrating device 105 may be an ultrasonic vibrating device.

[0030] In step S203, the fine droplets generated in advance are sprayed. Referring to FIG. 1, the fine droplets in the vibrator 105 can be transported and sprayed into the tube furnace 107 by the carrier gas.

[0031] In step S205, the atomized fine droplets are heated to produce powder. Referring to FIG. 1, the atomized fine droplets can be heated by heating the interior of the tubular furnace 107 at a high temperature. At this time, the atomized fine droplets are thermally decomposed by the heating. Specifically, nitride components in the atomized fine droplets are converted into oxides, and water in the atomized fine droplets is evaporated, forming a solid electrolyte powder in the form of solid particles.

[0032] According to one embodiment of the present invention, the atomized fine droplets can be heated to a temperature of 1,000° C. or more, thereby allowing the solid electrolyte powder produced through pyrolysis to be vitrified.

[0033] In step S207, the generated powder is collected. Referring to FIG. 1, the powder can be collected using a collector 109 including at least one of a bag filter and a cyclone. At this time, the carrier gas can be exhausted through an exhaust valve 111 connected to the collector 109, and the solid electrolyte powder can be collected in the collector 109.

[0034] According to this embodiment of the present invention, an oxide-based solid electrolyte powder having fine spherical particles can be obtained, and the produced oxide-based solid electrolyte powder can have a uniform particle size distribution. [Experimental Example] Hereinafter, the effects of the manufacturing method according to the embodiment of the present invention will be specifically described by comparing the oxide-based solid electrolyte powder manufactured according to the embodiment of the present invention with the oxide-based solid electrolyte powder manufactured by the conventional manufacturing method.

[0035] In the examples of the present invention, an oxide-based solid electrolyte powder having a composition system of Li-B-Al-O-Cl was prepared from a precursor aqueous solution containing Li2CO3, H3BO3, Al2O3, and LiCl by the above-mentioned method.

[0036] As a comparative example to the examples of the present invention, solid electrolyte powder was manufactured by a known melting method. Specifically, precursor powders containing Li2CO3, H3BO3, Al2O3, and LiCl were prepared, mixed, and then placed in an Al crucible and melted at about 1,000°C for 30 minutes. The melt was quenched on a brass roller, crushed, and sieved to obtain solid electrolyte powder with a size of 10 μm or less.

[0037] Figure 3 shows electron microscope images of oxide-based solid electrolyte powders according to an example and a comparative example of the present invention, where (a) in Figure 3 shows an electron microscope image of the oxide-based solid electrolyte powder according to a comparative example of the present invention, and (b) in Figure 3 shows an electron microscope image of the oxide-based solid electrolyte powder according to an example of the present invention.

[0038] 3, the powder prepared according to the embodiment of the present invention has a D50 of 1.0 μm or less, which is smaller in particle size and more uniform in particle size distribution than the comparative example, which has a D50 of around 3 μm. Also, the oxide-based solid electrolyte powder according to the comparative example has a rough and irregular particle surface, while the oxide-based solid electrolyte powder according to the embodiment of the present invention is composed of spherical particles.

[0039] As described above, the oxide-based solid electrolyte powder prepared by the method according to an embodiment of the present invention has a uniform particle size distribution and a spherical particle shape, which allows for fundamental removal of large particles and significantly reduces defects due to short circuits in the solid electrolyte layer during the manufacture of an all-solid-state battery.

[0040] 4A and 4B are electron microscope images showing the appearance of the oxide-based solid electrolyte powders according to an embodiment and a comparative example after sintering. Fig. 4A shows the appearance of the oxide-based solid electrolyte powder according to the comparative example, i.e., the oxide-based solid electrolyte powder prepared by a conventional technology (e.g., a melting method), after sintering, and Fig. 4B shows the appearance of the oxide-based solid electrolyte powder prepared according to an embodiment of the present invention after sintering.

[0041] 4, it can be seen that the oxide-based solid electrolyte powder prepared according to an embodiment of the present invention has a denser sintered structure than the oxide-based solid electrolyte powder prepared according to conventional techniques. As such, the oxide-based solid electrolyte powder prepared according to an embodiment of the present invention has an increased sintered density, which may lead to improved ionic conductivity. Therefore, the solid electrolyte prepared using the oxide-based solid electrolyte powder prepared according to an embodiment of the present invention may have superior battery characteristics compared to all-solid-state batteries prepared by conventional methods.

[0042] Table 1 shows the measurement results of the sintered density and ionic conductivity of the solid electrolyte of the oxide-based solid electrolyte powder according to an embodiment of the present invention and a comparative example. Referring to Table 1, it can be seen that the oxide-based solid electrolyte powder according to an embodiment of the present invention has improved sintered density and ionic conductivity compared to the oxide-based solid electrolyte powder according to the comparative example.

[0043] [Table 1]

[0044] 5 is a diagram schematically illustrating the cross-sectional structure of an all-solid-state battery manufactured using an oxide-based solid electrolyte powder according to an example and a comparative example of the present invention. When fabricating an oxide-based multi-layer ceramic battery (MLCB) for substrate mounting, the number of stacked solid electrolyte layers can be determined by the thickness of the sheets that make up the solid electrolyte layers. In other words, the thinner the thickness of each sheet, the more solid electrolyte layers can be stacked within the same volume.

[0045] As described above, the oxide-based solid electrolyte powder according to an embodiment of the present invention has a uniform particle size distribution and spherical fine particles, allowing the thickness of each sheet constituting the solid electrolyte layer to be as thin as 10 μm or less. Therefore, the all-solid-state battery manufactured using the oxide-based solid electrolyte powder according to an embodiment of the present invention (FIG. 5(b)) can have a larger number of stacked solid electrolyte layers than the all-solid-state battery according to the comparative example (FIG. 5(a)). This leads to an increase in the energy density of the all-solid-state battery, thereby increasing the battery capacity.

[0046] Meanwhile, it was confirmed that the oxide-based solid electrolyte powder according to an embodiment of the present invention had a vitrification temperature that was 15 to 20°C lower and a crystallization temperature that was 7 to 10°C lower than the oxide-based solid electrolyte powder according to the comparative example. Therefore, the oxide-based solid electrolyte powder according to an embodiment of the present invention can lower the sintering temperature and suppress the interfacial reaction between the electrolyte and the active material, thereby improving the lifespan of the all-solid-state battery.

[0047] Although the present invention has been described above using specific details such as specific components and limited examples, the above examples are merely provided to facilitate a more general understanding of the present invention, and the present invention is not limited thereto. Those skilled in the art to which the present invention pertains may make various modifications and variations from such descriptions.

[0048] Therefore, the concept of the present invention should not be limited to the above-described embodiments, and it can be said that not only the scope of the claims below but also all modifications equivalent to or similar to the scope of these claims fall within the scope of the concept of the present invention. [Explanation of symbols]

[0049] 100: Oxide-based solid electrolyte powder manufacturing equipment 101: Input pipe 103: Inlet valve 105: Vibration device 107:Tube furnace 109: Collection device 111: Exhaust valve

Claims

1. A method for producing an oxide-based solid electrolyte powder, comprising: Li ２ CO ３ , H ３ BO ３ , Al ２ O ３ and vibrating an aqueous precursor solution containing LiCl to generate fine droplets; spraying the fine droplets; heating the atomized fine droplets to form a powder; and collecting the powder produced.

2. The method of claim 1 , wherein the step of spraying the fine droplets comprises spraying the fine droplets into an interior of a tube furnace.

3. 10. The method of claim 1, wherein the step of producing the powder comprises heating the atomized fine droplets to a temperature of 1,000°C or higher.

4. The method of claim 1 , wherein the collecting the powder comprises collecting the powder through at least one of a bag filter and a cyclone.

5. 10. The method of claim 1, wherein the powder produced has a D50 of 2.0 μm or less.

6. An oxide-based solid electrolyte powder produced by the production method according to claim 1.

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