阅读说明：本技术 包含颗粒形式粘合剂的用于全固态电池的粘合剂溶液及其制造方法 (Binder solution for all-solid-state battery containing binder in particle form and method for manufacturing same ) 是由 金箱谟 李注妍 权兑荣 郑成厚 郑允晳 金圭太 吴大洋 于 2020-11-23 设计创作，主要内容包括：本申请公开了一种用于全固态电池的粘合剂溶液及其制造方法,该粘合剂溶液包含颗粒形式的粘合剂。该粘合剂溶液可包含基于橡胶的粘合剂,用于溶解基于橡胶的粘合剂的第一溶剂,和第二溶剂,基于橡胶的粘合剂在第二溶剂中不溶,且第二溶剂与第一溶剂可混溶。(Disclosed herein are a binder solution for an all-solid battery, which contains a binder in the form of particles, and a method for manufacturing the same. The adhesive solution may include a rubber-based adhesive, a first solvent for dissolving the rubber-based adhesive, and a second solvent in which the rubber-based adhesive is insoluble and which is miscible with the first solvent.)

1. A binder solution for an all-solid battery comprising:

a rubber-based adhesive;

a first solvent for dissolving the rubber-based adhesive; and

a second solvent in which the rubber-based adhesive is insoluble and which is miscible with the first solvent.

2. The binder solution according to claim 1, wherein the rubber-based binder comprises one or more selected from the group consisting of Nitrile Butadiene Rubber (NBR), Hydrogenated Nitrile Butadiene Rubber (HNBR), Styrene Butadiene Rubber (SBR), and Butadiene Rubber (BR).

3. The adhesive solution of claim 1, wherein the rubber-based adhesive is present in particulate form.

4. The adhesive solution of claim 1, wherein the average diameter of the rubber-based adhesive is 1,000nm or less.

5. The adhesive solution of claim 1 wherein the rubber-based adhesive has a polydispersity index, PDI, of 0.5 or less.

6. The adhesive solution of claim 1, wherein the difference R between the Hansen solubility parameters of the first solvent and the rubber-based adhesive_aIs 7 or less.

7. The adhesive solution of claim 1, wherein the difference R between the Hansen solubility parameters of the second solvent and the rubber-based adhesive_aGreater than 7.

8. The adhesive solution of claim 1, wherein the difference R between the Hansen solubility parameters of the first solvent and the second solvent_aIs 20 or less.

9. The adhesive solution of claim 1, wherein the first solvent comprises one or more selected from the group consisting of dibromomethane, benzyl acetate, ethyl 4-methylbenzoate, methyl 4-methylbenzoate, anisole, ethyl terephthalate, benzyl isobutyrate, and combinations thereof.

10. The adhesive solution of claim 1, wherein the second solvent comprises one or more selected from the group consisting of heptane, butyl butyrate, pentyl butyrate, hexyl butyrate, heptyl butyrate, and combinations thereof.

11. The binder solution according to claim 1, wherein the volume V of the first solvent₁Volume V of the second solvent₂Ratio V of₁:V₂Is 2:8 to 8: 2.

12. The adhesive solution of claim 1, wherein the content of the rubber-based adhesive is greater than 0 wt% and equal to or less than 20 wt%, and the sum of the contents of the first solvent and the second solvent is 80 wt% or more and less than 100 wt%, with wt% based on the total weight of the adhesive solution.

13. An electrode slurry for an all-solid battery comprising:

the binder solution of claim 1;

an electrode active material;

a conductive material; and

a solid electrolyte.

14. The electrode slurry of claim 13, wherein the electrode slurry comprises greater than 0 wt% and equal to or less than 30 wt% of the binder solution, greater than 0 wt% and equal to or less than 10 wt% of the conductive material, greater than 0 wt% and equal to or less than 20 wt% of the solid electrolyte, and a remaining amount of the electrode active material, wherein wt% is based on the total weight of the electrode slurry.

15. An electrode for an all-solid battery, comprising:

a rubber-based adhesive obtained from the adhesive solution of claim 1;

an electrode active material;

a conductive material; and

a solid electrolyte.

16. The electrode according to claim 15, wherein a ratio B/a of an electrochemical area B of the electrode active material to a total surface area a of the electrode active material is 0.2 or more and less than 1.

17. The electrode of claim 16, wherein the ratio B/a increases with increasing content of the second solvent in the binder solution.

18. A method of making the binder solution of claim 1, comprising the steps of:

mixing a rubber-based adhesive in a first solvent to form a mixture; and

adding a second solvent to the mixture of rubber-based adhesive and first solvent, the rubber-based adhesive being insoluble in the second solvent and the second solvent being miscible with the first solvent, thereby precipitating the rubber-based adhesive in particulate form.

Technical Field

The present invention relates to a binder solution for an all-solid battery, which contains a binder in the form of particles, and a method for manufacturing the same.

Background

An electrode for an all-solid battery includes an electrode active material and a solid electrolyte. The electrodes can be fabricated using a dry process or a wet process.

The dry method is a method of forming an electrode by pressing raw materials such as an electrode active material and a solid electrolyte, which are present in the form of powder. The dry method has an advantage in that the manufacture of the electrode is simple, but has a limitation in that it is difficult to increase the size of the electrode because the dry method is a method of pressing raw materials in the form of powder to manufacture the electrode.

The wet process is a method of forming an electrode by coating and drying an electrode slurry containing raw materials such as an electrode active material and a solid electrolyte. The wet process is more suitable for manufacturing large-scale electrodes than the dry process.

However, a binder must be added to the electrode slurry using a wet process in order to manufacture an electrode. The binder is used to adhere raw materials such as an electrode active material and a solid electrolyte, thereby maintaining the shape. However, the binder may cover the surfaces of particles such as the electrode active material and the solid electrolyte, thereby preventing movement of lithium ions in the electrode. Therefore, the binder may cause deterioration in the capacity, life and output characteristics of the battery.

Disclosure of Invention

In a preferred aspect, a regional adhesive is provided that provides adhesion between the constituent materials of the electrode and the all-solid battery in the form of particles. Preferably, by using a binder, the exposed area of the electrode active material and the solid electrolyte can be maximized, thereby forming a transport path of lithium ions in the electrode without hindrance.

In a preferred aspect, an all-solid-state battery is provided that includes a large-area electrode.

The objects of the present invention are not limited to the above objects and will be clearly understood from the following description and can be achieved by the means described in the claims and combinations thereof.

In one aspect, a binder solution for an all-solid battery is provided. The adhesive solution may include a rubber-based adhesive, a first solvent for dissolving the rubber-based adhesive, and a second solvent in which the rubber-based adhesive is insoluble and which is miscible with the first solvent.

As used herein, the term "binder" refers to a resin or polymeric material that can polymerize or cure to form a polymeric matrix. The adhesive may be cured (polymerized) or partially cured during a curing process such as heat, UV radiation, electron beam, chemical polymerization using additives, and the like. Preferably, the adhesive may contain a rubber component. For example, the adhesive is a rubber-based adhesive. The term "rubber-based ingredient" or "rubber-based adhesive" refers to a polymeric substance produced by polymerization of an unsaturated hydrocarbon (e.g., butylene or isoprene) or by copolymerization of an unsaturated or aromatic hydrocarbon (e.g., styrene or butadiene). In certain embodiments, the rubber-based adhesive may include a substituted group (e.g., nitrile or sulfonyl) on the hydrocarbon chain.

The rubber-based adhesive may suitably comprise one or more selected from the group consisting of Nitrile Butadiene Rubber (NBR), Hydrogenated Nitrile Butadiene Rubber (HNBR), and Styrene Butadiene Rubber (SBR), Butadiene Rubber (BR).

The rubber-based adhesive may be present in particulate form.

The rubber-based adhesive may suitably have an average diameter of about 1,000nm or less.

The rubber-based adhesive may suitably have a polydispersity index (PDI) of about 0.5 or less.

Difference between Hansen (Hansen) solubility parameters (R) of first solvent and rubber-based adhesive_a) And may be about 7 or less.

Difference between hansen solubility parameter (R) of second solvent and rubber-based adhesive_a) And may be greater than about 7.

Difference between hansen solubility parameters (R) of first and second solvents_a) And may be about 20 or less.

The first solvent may comprise one or more selected from dibromomethane, benzyl acetate, ethyl 4-methylbenzoate, methyl 4-methylbenzoate, anisole, ethyl terephthalate, and benzyl isobutyrate.

The second solvent may comprise any one selected from the group consisting of heptane, butyl butyrate, pentyl butyrate, hexyl butyrate, heptyl butyrate, and combinations thereof.

Volume of first solvent (V)₁) Volume (V) with second solvent₂) Ratio of (V)₁:V₂) And may be about 2:8 to 8: 2.

The content of the rubber-based adhesive may be greater than 0 wt% and equal to about or less than about 20 wt%, and the sum of the content of each of the first solvent and the second solvent may be about 80 wt% or more and less than about 100 wt%, because the wt% is based on the total weight of the adhesive solution.

In one aspect, an electrode slurry for an all-solid battery is provided, which may include the binder solution, the electrode active material, the conductive material, and the solid electrolyte described herein.

The electrode paste may include greater than 0 wt% and equal to about or less than about 30 wt% of the binder solution, greater than 0 wt% and equal to about or less than about 10 wt% of the conductive material, greater than 0 wt% and equal to about or less than about 20 wt% of the solid electrolyte, the wt% being based on the total weight of the electrode paste, and the remaining amount of the electrode active material.

Also provided is an electrode for an all-solid battery, which may include a rubber-based binder obtained from the above binder solution, an electrode active material, a conductive material, and a solid electrolyte.

In the electrode, a ratio (B/a) of an electrochemical area (B) of the electrode active material to a total surface area (a) of the electrode active material may be about 0.2 or more and less than about 1.

In the electrode, the ratio (B/a) may increase as the content of the second solvent in the binder solution increases.

In one aspect, there is provided a method of manufacturing a binder solution for an all-solid battery, which may include the steps of: the rubber-based adhesive and the first solvent are mixed to form a mixture, and a second solvent is added to the mixture, the rubber-based adhesive being insoluble in the second solvent, and the second solvent being miscible with the first solvent, thereby precipitating the rubber-based adhesive in particulate form.

According to various exemplary embodiments of the present invention, the binder may provide a binding force between constituent materials of the electrode in the form of particles, and thus may maximize an exposed area of the electrode active material and the solid electrolyte, thereby forming an unobstructed lithium ion transport path in the electrode.

In addition, an all-solid battery including a large-area electrode can be provided.

The effects of the present invention are not limited to the foregoing, and should be understood to include all effects that can be reasonably expected from the following description.

Other aspects of the invention are disclosed below.

Drawings

Fig. 1A to 1C illustrate results of analyzing the degree of precipitation of exemplary rubber-based adhesives according to examples 1 to 3 of exemplary embodiments of the present invention using Dynamic Light Scattering (DLS);

fig. 2A to 2D illustrate electrodes fabricated using the exemplary binder solutions of examples 2 to 5 according to an exemplary embodiment of the present invention;

fig. 3 shows the results of analyzing exemplary electrodes manufactured using the binder solutions of examples 2 and 3 according to an exemplary embodiment of the present invention by a constant current intermittent titration technique (GITT);

fig. 4A illustrates measurement results of charge and discharge capacities of electrodes manufactured using binder solutions of examples 2 and 3 and comparative example 1 according to an exemplary embodiment of the present invention;

fig. 4B shows the measurement results of the rate determining characteristics of the electrodes manufactured using the binder solutions of examples 2 and 3 and comparative example 1 according to an exemplary embodiment of the present invention;

fig. 5A illustrates measurement results of charge and discharge capacities of exemplary electrodes manufactured using the exemplary binder solutions of examples 4 and 5 according to an exemplary embodiment of the present invention; and

fig. 5B shows the measurement results of the rate-determining characteristics of exemplary electrodes manufactured using the exemplary binder solutions of examples 4 and 5 according to an exemplary embodiment of the present invention.

Detailed Description

The above and other objects, features and advantages of the present invention will be more clearly understood through the following preferred embodiments. However, the present invention is not limited to the embodiments disclosed herein, and may be modified into various forms. These embodiments are provided to explain the present invention in detail and to fully convey the spirit of the invention to those skilled in the art.

The same reference numbers will be used throughout the drawings to refer to the same or like elements. For clarity of the invention, the dimensions of the structures are described as being larger than their actual dimensions. It will be understood that, although terms such as "first," "second," etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a "first" element discussed below could be termed a "second" element without departing from the scope of the present invention. Similarly, a "second" element may also be referred to as a "first" element. As used herein, the singular forms also are intended to include the plural forms as well, unless the context clearly indicates otherwise.

It will be further understood that the terms "comprises," "comprising," "includes," "including," and the like, when used in this specification, specify the presence of stated features, integers, steps, operations, elements, components, or groups thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or groups thereof. Also, it will be understood that when an element such as a layer, film, region, or sheet is referred to as being "on" another element, it can be directly on the other element or intervening elements may be present therebetween. Similarly, when an element such as a layer, film, region, or sheet is referred to as being "under" another element, it can be directly under the other element or intervening elements may be present therebetween.

Unless otherwise indicated, all numbers, values and/or expressions referring to amounts of ingredients, reaction conditions, polymer compositions and mixtures used herein are to be considered approximate, including the various uncertainties affecting measurements that occur primarily in the process of obtaining such values and the like, and thus are to be understood as modified in all instances by the term "about". Unless specifically stated otherwise or clear from the context, the term "about" as used herein is to be understood as being within the normal tolerance of the art, e.g., within 2 standard deviations of the mean. "about" can be understood as being within 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, 0.5%, 0.1%, 0.05% or 0.01% of the stated value. Unless otherwise clear from the context, all numbers provided herein are modified by the term "about".

Further, unless otherwise indicated, when a range of values is disclosed in this specification, the range is continuous and includes all values from the minimum value to the maximum value of the range. Further, when such ranges refer to integer values, all integers from the minimum to the maximum are included unless otherwise specified.

For example, a range of "5 to 10" will be understood to include any subrange, such as 6 to 10, 7 to 10, 6 to 9, 7 to 9, and the like, as well as individual values within 5, 6, 7, 8, 9, and 10, and will also be understood to include any value between significant integers within the range, such as 5.5, 6.5, 7.5, 5.5 to 8.5, 6.5 to 9, and the like. Further, a range such as "10% -30%" will be understood to include sub-ranges such as 10% -15%, 12% -18%, 20% -30%, etc., as well as all integers including values of 10%, 11%, 12%, 13%, etc. up to 30%, and will also be understood to include any value between the effective integers within the range, such as 10.5%, 15.5%, 25.5%, etc.

In one aspect, an adhesive solution for an all-solid battery may include a rubber-based adhesive, a first solvent for dissolving the rubber-based adhesive, and a second solvent in which the rubber-based adhesive is insoluble.

The rubber-based adhesive is present therein in the form of particles by mixing them simultaneously with the rubber-based adhesive by using together a first solvent in which the rubber-based adhesive is soluble and a second solvent in which the rubber-based adhesive is insoluble.

When the electrode slurry is manufactured using a binder solution in which the rubber-based binder is present in the form of particles, the rubber-based binder can bind constituent components while minimizing coverage of the surfaces of the electrode active material and the solid electrolyte. Therefore, since the degree of interference of the rubber-based binder is reduced, a transport path of lithium ions can be formed in the electrode without hindrance.

The rubber-based adhesive may comprise one or more selected from the group consisting of Nitrile Butadiene Rubber (NBR), Hydrogenated Nitrile Butadiene Rubber (HNBR), Styrene Butadiene Rubber (SBR), and Butadiene Rubber (BR).

The rubber-based adhesive may be present in the form of particles, and may have an average diameter of about 1,000nm or less. An average diameter of the rubber-based binder greater than about 1,000nm may disturb the formation of an unobstructed transport path for lithium ions in the electrode. The lower limit of the average diameter of the rubber-based adhesive is not particularly limited, but may be, for example, about 100nm, about 200nm, or about 300 nm.

The rubber-based adhesive may have a polydispersity index (PDI) of about 0.5 or less. When the polydispersity index of the rubber-based adhesive is greater than about 0.5, the rubber-based adhesive may be difficult to exist in a particulate form. The lower limit of the polydispersity index of the rubber-based adhesive is not particularly limited, but may be, for example, about 0.1, about 0.15, or about 0.18.

As described above, the first solvent for dissolving the rubber-based adhesive and the second solvent in which the rubber-based adhesive is insoluble and which is miscible with the first solvent may be mixed with each other and used. When the rubber-based adhesive is mixed with the second solvent in a state of being dissolved in the first solvent, the rubber-based adhesive may be in a supersaturated state and thus may be aggregated to be precipitated in the form of particles.

Preferably, the difference (R) from the Hansen Solubility Parameter (HSP) of a rubber-based adhesive_a) A solvent of about 7 or less may be used as the first solvent.

Furthermore, the difference in Hansen Solubility Parameters (HSP) with rubber-based adhesives (R)_a) A solvent greater than about 7 may be used as the second solvent.

In order to determine solubility or miscibility between materials, the similarity between materials must be compared using the inherent properties of the materials. There are many intrinsic properties that affect solubility or miscibility, but the most common of these is the solubility parameter, which represents the degree of binding (interaction) in the material in quantitative terms. That is, each material has a unique solubility parameter value, and materials with similar solubility parameter values dissolve or mix well with each other.

Solubility parameters have been proposed and used based on various theories or concepts, but among them, Hansen Solubility Parameters (HSP) proposed by doctor c. Considering the degree of incorporation in a material, the hansen solubility parameter can be subdivided into the following three parameters:

(1) solubility parameter (. delta.) due to non-polar Dispersion combination_d)；

(2) Solubility parameter (. delta.) due to permanent dipole induced polar binding_p) (ii) a And

(3) solubility parameter (delta) due to hydrogen bonding_h)。

HSP＝(δ_d,δ_p,δ_h),(J/cm³)^1/2

The Hansen Solubility Parameter (HSP) given above refers to a vector having a size and directionality in a space composed of three elements, and represents that its basic unit is (J/cm)³)^1/2. Each vector value of hansen solubility parameters can be calculated using a program called HSPiP (hansen solubility parameters in practice) developed by the team of doctrines c.

As described above, Hansen Solubility Parameters (HSPs) provide information that binds to a material in greater detail than other solubility parameters, so that the solubility or miscibility of the material can be assessed more accurately and systematically. Thus, the hansen solubility parameter has been widely used.

When the vector values of the Hansen Solubility Parameters (HSPs) of two materials are similar to each other, the materials dissolve well into each other. Since the Hansen Solubility Parameter (HSP) is a vector, the size of all three vectors must be similar for each material in order to conclude that these parameters are similar to each other. This may be due to the difference (R) between the Hansen Solubility Parameters (HSP) of the two materials_a) And (4) showing. Difference (R) between Hansen Solubility Parameters (HSP)_a) Reduced, improved solubility and miscibility.

(R_a)²＝4(δ_d2-δ_d1)²+(δ_p2-δ_p1)²+(δ_h2-δ_h1)²

Due to the difference between the Hansen Solubility Parameters (HSP) of the first solvent and the rubber-based adhesive: (HSP)R_a) Small and thus the rubber-based adhesive dissolves in the first solvent. In contrast, the difference (R) between the Hansen Solubility Parameter (HSP) due to the second solvent and the rubber-based adhesive_a) Larger and thus the rubber-based adhesive is insoluble in the second solvent.

Meanwhile, in order to improve dispersibility of the rubber-based adhesive in the adhesive solution, solvents that are miscible with each other may be preferably used as the first solvent and the second solvent. For example, the difference (R) between the Hansen Solubility Parameters (HSP) of the first and second solvents_a) And may be 20 or less.

Preferably, the first solvent and the second solvent are stable as a liquid at room temperature, under atmospheric pressure, or under storage conditions. Therefore, the boiling points of the first solvent and the second solvent are preferably at a predetermined temperature or higher. For example, the boiling points of the first solvent and the second solvent may be 150 ℃ or higher.

In addition, from the economical point of view, it is preferable that the boiling points of the first solvent and the second solvent are a predetermined level or less and the vapor pressure is a predetermined level or more so that the first solvent and the second solvent are dried without consuming a large amount of thermal energy. For example, at room temperature, the first solvent and the second solvent may have boiling points of about 300 ℃ or less and a vapor pressure of about 0.001 to 10 mmHg.

Preferably, the first solvent may suitably comprise one or more selected from dibromomethane, benzyl acetate, ethyl 4-methylbenzoate, methyl 4-methylbenzoate, anisole, ethyl p-benzoate and benzyl isobutyrate.

The second solvent may comprise one or more selected from the group consisting of heptane, butyl butyrate, pentyl butyrate, hexyl butyrate, and heptyl butyrate.

The Hansen Solubility Parameters (HSPs) of the first and second solvents are shown in table 1 below.

TABLE 1

Volume of first solvent (V)₁) With a second solventVolume (V) of₂) Ratio of (V)₁:V₂) And may be about 2:8 to 8: 2. When the volume of the first solvent is small, the rubber-based adhesive may not be sufficiently dissolved in the first solvent. When the volume of the first solvent is large, the volume of the second solvent is relatively small, and thus the rubber-based adhesive may not precipitate.

In the adhesive solution, the content of the rubber-based adhesive may be greater than 0 wt% and equal to about or less than about 20 wt%, and the sum of the contents of the first solvent and the second solvent may be 80 wt% or more and equal to about or less than about 100 wt%, based on the total weight of the adhesive solution. When the content of the rubber-based adhesive is more than 20 wt%, the rubber-based adhesive may not be dissolved in the first solvent.

The electrode slurry for an all-solid battery may include the above-described binder solution, an electrode active material, a conductive material, and a solid electrolyte.

The electrode paste may include the binder solution in an amount of greater than 0 wt% and equal to or less than about 30 wt%, the conductive material in an amount of greater than 0 wt% and equal to or less than about 10 wt%, the solid electrolyte in an amount of greater than 0 wt% and equal to or less than about 20 wt%, the wt% being based on the total weight of the electrode paste, and the remaining amount of the electrode active material. The content is not particularly limited, and the content of each component may be appropriately adjusted depending on the purpose and effect to be achieved.

The electrode for an all-solid battery may include a rubber-based binder obtained from the above-described binder solution, an electrode active material, a conductive material, and a solid electrolyte.

The rubber-based adhesive may be present in the adhesive solution in particulate form. As described above, the rubber-based adhesive provides adhesion between components while minimizing coverage of the surfaces of the electrode active material, the conductive material, and the solid electrolyte. Therefore, the exposed area of the electrode active material and the solid electrolyte increases, and the contact area between the two constituent components increases. Therefore, a transport path of lithium ions can be formed in the electrode without hindrance.

In the electrode, a ratio (B/a) of an electrochemical area (B) of the electrode active material to a total surface area (a) of the electrode active material may be about 0.2 or more and less than about 1.

The total surface area (a) of the electrode active material means a value obtained by multiplying the BET specific surface area of the electrode active material by the weight of the electrode active material contained in the electrode. The electrochemical area (B) of the electrode active material refers to an electrochemical contact area between the electrode active material and the solid electrolyte, which can be measured using a constant current intermittent titration technique (GITT).

The electrochemical area obtained using GITT can be measured by current application time (τ), ion diffusion coefficient (D) in the electrode active material, atomic weight (M) of the electrode active material_B) Mass (m) of electrode active material_B) Potential difference (Δ E) of current application time_t) Equilibrium potential difference (Δ E) between unit current application times_s) To measure.

The electrode active material may be a positive electrode active material or a negative electrode active material.

The positive electrode active material is not particularly limited, but may be, for example, an oxide active material or a sulfide active material.

The oxide active material may be a rock salt layer type active material, such as LiCoO₂、LiMnO₂、LiNiO₂、LiVO₂Or Li_1+xNi_1/3Co_1/3Mn_1/3O₂Spinel type active materials such as LiMn₂O₄Or Li (Ni)_0.5Mn_1.5)O₄Inverse spinel type active materials such as LiNiVO₄Or LiCoVO₄Olivine-type active materials such as LiFePO₄、LiMnPO₄、LiCoPO₄Or LiNiPO₄Silicon-containing active materials such as Li₂FeSiO₄Or Li₂MnSiO₄Rock-salt-type active materials in which a portion of the transition metal is replaced by a dissimilar metal, e.g. LiNi_0.8Co_(0.2-x)Al_xO₂(0 < x < 0.2), spinel-type active materials in which a part of the transition metal is replaced by a dissimilar metal, e.g. Li_1+xMn_2-x-yM_yO₄(M is at least one of Al, Mg, Co, Fe, Ni and Zn, and 0 < x + y < 2), or a lithium titanate, such as Li₄Ti₅O₁₂。

The sulfide active material may suitably comprise scherrer phase copper (copper chevrel), iron sulfide, cobalt sulfide or nickel sulfide.

The anode active material is not particularly limited, but may be, for example, a carbon active material or a metal active material.

The carbon active material may suitably comprise mesocarbon microbeads (MCMB), graphite such as highly oriented graphite (HOPG), or amorphous carbon such as hard and soft carbon.

The metal active material may suitably comprise In, Al, Si, Sn or an alloy comprising one or more of these elements.

The conductive material is a constituent that forms an electron conduction path in the electrode. The conductive material may be sp²Carbon materials, such as carbon black, conductive graphite, ethylene black or carbon nanotubes or graphene.

The solid electrolyte may be an oxide-based solid electrolyte or a sulfide-based solid electrolyte. However, a sulfide-based solid electrolyte having high lithium ion conductivity may be preferably used.

The sulfide-based solid electrolyte may suitably contain Li₂S-P₂S₅、Li₂S-P₂S₅-LiI、Li₂S-P₂S₅-LiCl、Li₂S-P₂S₅-LiBr、Li₂S-P₂S₅-Li₂O、Li₂S-P₂S₅-Li₂O-LiI、Li₂S-SiS₂、Li₂S-SiS₂-LiI、Li₂S-SiS₂-LiBr、Li₂S-SiS₂-LiCl、Li₂S-SiS₂-B₂S₃-LiI、Li₂S-SiS₂-P₂S₅-LiI、Li₂S-B₂S₃、Li₂S-P₂S₅-Z_mS_n(m and n are positive numbers, and Z is any one of Ge, Zn and Ga), Li₂S-GeS₂,Li₂S-SiS₂-Li₃PO₄,Li₂S-SiS₂-Li_xMO_y(x and y are positive numbers, and M is any one of P, Si, Ge, B, Al, Ga and In) or Li₁₀GeP₂S₁₂。

In one aspect, a method of manufacturing an adhesive solution for an all-solid battery may include dissolving a rubber-based adhesive in a first solvent, and adding a second solvent to the resulting product, the rubber-based adhesive being insoluble in the second solvent, and the second solvent being miscible with the first solvent, thereby precipitating the rubber-based adhesive in particle form.

The rubber-based adhesive, the first solvent and the second solvent are described above, and detailed description thereof will be omitted hereinafter.

The method of precipitating the rubber-based adhesive is not particularly limited. However, for example, stirring may be performed under predetermined conditions while adding the second solvent.

Examples

Hereinafter, other forms of the present invention will be described in more detail by way of examples. The following examples are only examples to aid understanding of the present invention, and the scope of the present invention is not limited thereto.

Examples 1 to 7 and comparative examples 1 to 3

The adhesive solution was manufactured to have the composition described in table 2 below.

TABLE 2

The rubber-based adhesives of examples 1 to 3 were analyzed for degree of precipitation using Dynamic Light Scattering (DLS). The results are shown in FIGS. 1A to 1C. Fig. 1A shows the results of example 1, fig. 1B shows the results of example 2, and fig. 1C shows the results of example 3.

As shown in fig. 1A to 1C, as the volume of the second solvent increases, the particle size distribution of the precipitated rubber-based adhesive decreases. This means that as the volume of the second solvent increases, the rubber-based adhesive precipitates more uniformly.

Table 3 below shows the average diameters (D) of the rubber-based adhesives precipitated according to examples 1 to 7 and comparative examples 1 to 3_avg) And polydispersity index (PDI).

Average diameter (D) of rubber-based adhesive_avg) And polydispersity index (PDI) is measured using the Dynamic Light Scattering (DLS) method.

TABLE 3

Classification	Average diameter [ nm ]]	PDI[A.U.]
			Example 1	429.8	0.297
Example 2	354.1	0.216
			Example 3	515.3	0.186
Example 4	632.9	0.434
			Example 5	442.8	0.190
Example 6	501.4	0.384
			Example 7	526.1	0.288
Comparative example 1	1567.0	0.714
			Comparative example 2	5792.4	0.608
Comparative example 3	3036.4	0.843

As shown in table 3, all of the precipitated rubber-based adhesives of examples 1 to 7 had an average diameter of 1,000nm or less and had a polydispersity index (PDI) of 0.5 or less.

On the other hand, although the average diameters of comparative examples 1 to 3 were calculated, it is hard to say that the rubber-based adhesive is precipitated in the form of particles because the polydispersity index (PDI) is large.

Experimental example 1 production of electrode

The binder solutions according to examples 2 to 5 were used to manufacture electrodes. Making an electrode slurry comprising a binder solution as an electrode activeLiNi of Material_0.7Co_0.15Mn_0.15O₂Super C65 as a conductive material and Li as a solid electrolyte₆PS₅And (4) Cl. The electrode slurry contained 1.5 wt% of the binder solution, 70.0 wt% of the electrode active material, 1.0 wt% of the conductive material, and 27.5 wt% of the solid electrolyte.

Each electrode paste was applied to a substrate to evaluate formability. The results are shown in fig. 2A to 2D. Fig. 2A shows the results of example 2, fig. 2B shows the results of example 3, fig. 2C shows the results of example 4, and fig. 2D shows the results of example 5. As shown in fig. 2A to 2D, all the electrodes are suitably formed without cracking or breaking. Therefore, when the binder solution according to the present invention is used, the adhesion of the electrode to each component is sufficient, and thus there is no difficulty in forming the electrode.

Experimental example 2-ratio (B/A) of electrochemical area (B) of electrode active material to total surface area (A) of electrode active material

Electrodes were made using the binder solutions of examples 2 and 3. The electrochemical surface area of each electrode was calculated using the constant current intermittent titration technique (GITT). The results are shown in fig. 3 and table 4 below.

TABLE 4

Item	Example 2	Example 3
			Weight of electrode active Material [ g]	8.26	9.17
BET specific surface area [ cm ] of electrode active material2/g]	3,337	3,337
			Total surface area (A) [ cm ] of electrode active material2]	27,563	30,600
Electrochemical surface area (B) [ cm ] of electrode active material2]	3,035	7,602
			B/A	0.1101	0.2484

As shown in fig. 3 and table 4, since the content (volume) of the second solvent is greater in example 3 than in example 2, the rubber-based adhesive is more uniformly precipitated. Therefore, the contact area between the solid electrolyte and the electrode active material is increased, and the B/a value is high.

Experimental example 3 evaluation of Charge and discharge Capacity and Rate-determining characteristics

The charge and discharge capacity and rate determining characteristics of the electrode using the binder solution according to examples 2 and 3 and comparative example 1 were measured. The results are shown in FIGS. 4A and 4B.

As shown in fig. 4A and 4B, the electrodes using the binder solutions according to examples 2 and 3 have a large charge and discharge capacity, a reduced overvoltage, and improved rate-determining characteristics, as compared with the case of comparative example 1.

The charge and discharge capacity and rate determining characteristics of the electrodes using the binder solutions according to examples 4 and 5 were measured. The results are shown in FIGS. 5A and 5B.

As shown in fig. 5A and 5B, the electrodes using the binder solutions according to examples 4 and 5 had large charge and discharge capacities of 150mAh/g and excellent rate-determining characteristics.

As described above, the present invention has been described in detail with respect to test examples and embodiments. However, the scope of the present invention is not limited to the above-described test examples and embodiments, and various modifications and improvement modes of the present invention using the basic concept of the present invention defined in the claims are also incorporated into the scope of the present invention.