KR20180131448A - all solid secondary battery and manufacturing thereof - Google Patents

Abstract

Provided are an all-solid secondary battery which can prevent short circuit and is novel and modified, and a method for manufacturing an all-solid secondary battery. In order to overcome problems, according to one aspect of the present invention, provided is an all-solid secondary battery which comprises a positive electrode active material layer, a negative electrode active material layer, and a solid electrolyte layer interposed between the positive electrode active material layer and the negative electrode active material layer, wherein an arithmetic mean illumination (Ra) on an interface of the positive electrode active material layer and the solid electrolyte layer is less than or equal to 1.0 μm, and relative density of the solid electrolyte layer is more than or equal to 80%. According to the present invention, if lithium metal is contained in the negative electrode active material layer, short circuit can be prevented.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a solid secondary battery,

The present invention relates to a pre-solid secondary battery and a method for manufacturing the pre-solid secondary battery.

In recent years, all solid secondary batteries disclosed in, for example, Patent Documents 1 and 2 have attracted attention. The entire solid secondary battery includes a positive electrode active material layer, a negative electrode active material layer, and a solid electrolyte layer sandwiched between the positive electrode active material layer and the negative electrode active material layer. A solid secondary battery is a solid electrolyte in which a lithium ion is conducted.

In order to increase the energy density of such a pre-solid secondary battery, it has been proposed to use metal lithium as an anode active material. The use of metal lithium as an anode active material makes it possible to increase the output while flattening the entire solid secondary battery.

On the other hand, since the medium which conducts lithium ions in the pre-solid secondary battery is a solid electrolyte, the characteristics of the battery can be improved by densifying the particles constituting the pre-solid secondary battery. In addition, from the viewpoint of increasing the energy density of the entire solid secondary battery, it is required to make the solid electrolyte layer thinner.

Therefore, when the entire solid secondary battery is fabricated, the electrode laminate, which is a lamination of the positive electrode active material layer, the solid electrolyte layer and the negative electrode active material layer, is often pressed. So that the in-layer and inter-layer particles can be clustered together. Further, the solid electrolyte layer can be made thinner. Nonetheless, there is a need for an improved pre-solid secondary battery and a method of manufacturing the same.

Japanese Patent Application Publication No. 2015-125872 International Publication No. 2014/010042

However, metal lithium is very fragile. Therefore, when metal lithium is used as the negative electrode active material, the following problems may occur. That is, when cracks, such as cracks, are generated on the surface of the solid electrolyte layer, metal lithium enters the gap during pressing of the electrode laminate. And, when this gap communicates at the front and back surfaces of the solid electrolyte layer, the metal lithium could reach the cathode active material layer. Therefore, the entire solid secondary battery could be short-circuited. In addition, even when the gap does not communicate with the front and back surfaces, the distance between the metallic lithium and the cathode active material layer which penetrates into the gap becomes shorter than the distance between the surface of the metallic lithium and the cathode active material layer. Therefore, at the time of charging, a current may be concentrated at this portion, and a short circuit may occur.

Further, when the surface of the positive electrode active material layer and the surface of the solid electrolyte layer are rough, the following problems may occur. That is, on the surface of the positive electrode active material layer, protrusions protruding toward the negative electrode active material layer (i.e., metal lithium) are formed. Therefore, at the time of filling, the distance between the protruding portion and the negative electrode active material layer becomes shorter than the distance between the other portion of the positive electrode active material layer and the negative electrode active material layer. Therefore, at the time of charging, a current may be concentrated at this portion, and a short circuit may occur.

As described above, when metallic lithium is used as the negative electrode active material of the pre-solid secondary battery, a short circuit may occur.

DISCLOSURE Technical Problem Accordingly, the present invention has been made in view of the above problems, and it is an object of the present invention to provide a new and improved pre-solid secondary battery and a pre-solid secondary battery capable of preventing occurrence of a short circuit when metal lithium is contained in the anode active material layer .

According to one aspect of the present invention, there is provided a positive electrode comprising a positive electrode including a positive electrode active material layer, a negative electrode including a negative electrode active material layer, and a solid electrolyte interposed between the positive electrode active material layer and the negative electrode active material layer And a solid electrolyte layer, wherein the arithmetic mean roughness (Ra) at the interface between the positive electrode active material layer and the solid electrolyte layer is 1.0 占 퐉 or less, and the density ratio of the solid electrolyte layer is 80% or more.

According to an aspect of the present invention, there is also provided a cathode comprising: a cathode comprising a cathode active material layer; A negative electrode including a negative electrode current collector and including a negative electrode active material layer on the negative electrode current collector; And a solid electrolyte layer sandwiched between the positive electrode active material layer and the negative electrode active material layer, wherein the negative electrode active material layer includes carbon, and a plating layer is interposed between the negative electrode collector and the negative electrode active material layer , The plating layer comprises lithium, the arithmetic mean roughness at the interface between the cathode active material layer and the solid electrolyte layer is 1.0 m or less, and the solid electrolyte layer density ratio is 80% or more. do.

According to this aspect, since the arithmetic mean roughness (Ra) at the interface between the positive electrode active material layer and the solid electrolyte layer is 1.0 占 퐉 or less, current flows more uniformly in the solid electrolyte layer at the time of charging the entire solid secondary battery. Therefore, metal lithium is more uniformly precipitated in the negative electrode active material layer, so that occurrence of a short circuit becomes difficult. Further, since the relative density of the solid electrolyte layer is 80% or more, the gap between the solid electrolyte layers is reduced and becomes smaller. As a result, the occurrence of a short circuit becomes difficult.

Here, the relative density of the positive electrode active material layer may be 60% or more.

According to this aspect, the characteristics of the entire solid secondary battery cell are improved.

Further, the maximum height roughness Rz at the interface between the positive electrode active material layer and the solid electrolyte layer may be 4.5 占 퐉 or less.

According to this aspect, current flows more uniformly in the solid electrolyte layer at the time of charging the entire solid secondary battery. Therefore, metal lithium is more uniformly deposited on the negative electrode active material layer, so that occurrence of a short circuit becomes difficult.

Further, the thickness of the solid electrolyte layer may be 100 占 퐉 or less.

According to this aspect, the energy density of the entire solid secondary battery is improved.

According to another aspect of the present invention, there is provided a method for manufacturing a pre-solid-state secondary battery, comprising the steps of: providing a cathode active material layer; Providing a negative electrode active material layer; Providing a solid electrolyte layer comprising a solid electrolyte; And pre-pressing the positive electrode active material layer and the solid electrolyte layer; And a step of pressing the electrode stacked body including the positive electrode active material layer and the solid electrolyte layer pressed in the preliminary press process and the negative electrode active material layer to manufacture the pre-solidified secondary battery, wherein the positive electrode active material layer and the solid electrolyte The pre-pressing step includes pressing the cathode active material layer before laminating the pressed cathode active material layer to the solid electrolyte layer, providing the pressed cathode active material layer, and stacking the pressed solid electrolyte layer on the anode active material layer Wherein the solid electrolyte layer is pressed before the solid electrolyte layer is pressed to provide a pressed solid electrolyte layer.

According to this aspect, a full solid secondary battery having the above characteristics can be manufactured.

Here, in the step of pressing the positive electrode active material layer, the positive electrode active material layer can be pressed together with the positive electrode collector.

According to this aspect, a full solid secondary battery having the above characteristics can be manufactured.

Further, the step of pressing the solid electrolyte layer may include a step of pressing the solid electrolyte layer alone, which presses the solid electrolyte layer before laminating the pressed positive electrode active material layer.

According to this aspect, a full solid secondary battery having the above characteristics can be manufactured.

Further, the step of pressing the solid electrolyte layer includes: a step of pressing the solid electrolyte layer alone; And pressing the first intermediate laminate as a laminate of the pressed positive electrode active material layer provided by pressing the positive electrode active material layer provided by the step of pressing the solid electrolyte layer alone, .

According to this aspect, a full solid secondary battery having the above characteristics can be manufactured.

Further, the step of pressing the solid electrolyte layer includes: a step of pressing the solid electrolyte layer alone; And pressing the second intermediate laminate, which is a laminate of the solid electrolyte layer, and the pressed positive electrode active material layer pressed in the step of pressing the positive electrode active material layer.

According to this aspect, a full solid secondary battery having the above characteristics can be manufactured.

The method may further include the steps of providing a positive electrode including a positive electrode active material layer, disposing a solid electrolyte layer on the positive electrode, Disposing a negative electrode on the solid electrolyte layer; And forming a plating layer between the anode active material layer and the anode current collector by providing a voltage between the anode and the cathode to fabricate the pre-solid-state secondary battery, wherein the cathode includes an anode current collector, There is provided a method of manufacturing a pre-solid secondary battery including an anode active material layer on an anode current collector.

INDUSTRIAL APPLICABILITY As described above, according to the present invention, when metallic lithium is contained in the negative electrode active material layer, short circuit can be prevented.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1A is a diagram showing a schematic configuration of a full solid secondary battery according to an embodiment of the present invention; FIG.
1B is a diagram showing a schematic configuration of a pre-solid-state secondary battery according to an embodiment of the present invention.
2 is a view showing a solid electrolyte layer and its surrounding structure.
3 is a cross-sectional SEM (electron microscope) photograph showing the interface between the solid electrolyte layer and the cathode active material layer and its surrounding structure.
4 is a view for explaining a problem of a conventional all-solid-state secondary battery.
5 is a view for explaining a problem of a conventional all-solid-state secondary battery.
6 is a view for explaining a problem of a conventional all-solid-state secondary battery.
7 is a SEM photograph of a cross-section of a conventional solid-state secondary battery.
8 is a cross-sectional SEM photograph for explaining a method of measuring the arithmetic average roughness (Ra) at the interface between the solid electrolyte layer and the cathode active material layer.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In this specification and drawings, constituent elements having substantially the same functional configuration are denoted by the same reference numerals, and redundant description will be omitted.

It will be appreciated that an element is " on " another element, either directly on the other element or intervening elements. On the other hand, the fact that an element is " directly on " another element means that no configuration exists between them.

The terms "first", "second", "third", etc. may be used herein to describe various elements, components, components, regions, layers, and / , Regions, layers, and / or sections are not intended to be limiting to such terms. These terms are used to distinguish just one element, component, region, layer, or section from another component, component, region, layer or section. Thus, the terms " first element, " " component, " " area, " " layer, " or " part, " Can be named.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting thereof. As used herein, the singular forms "a," "an," and "the" are intended to include the plural, including "at least one", unless the context clearly dictates otherwise. "At least one" should not be limited to "one" or "one." Or " as used herein, the term " and / or " includes any and all combinations of one or more of the associated list lists. The terms " comprise " and / or " comprising ", or " includes " and / or " , Steps, drives, components, and / or components, but does not preclude the presence or addition of one or more other features, regions, numbers, steps, drives, components, components, and / .

Further, the relative terms "lower" or "lower" and "upper" or "upper" are used to describe the relationship between one component and another component as shown in the drawings. Relative concepts are intended to include other arrangements of devices in addition to the arrangements shown in the drawings. For example, when turning the device upside down in one of the figures, the elements described as being on the " bottom " side of the other elements will be arranged on the " Thus, an exemplary term " lower " may encompass an array of "lower" or "upper", depending on the particular arrangement of the figures. Similarly, if the device is reversed in any one of the figures, the elements located " below " other elements will be " above " other elements. Accordingly, the exemplary term " below " can encompass both the arrays below and above.

As used herein, " about " or " approximately " refers to a measure of a given value within a tolerable error range for a particular value determined by a descriptor, taking into account measurement errors and errors associated with measurement of a particular quantity Value and average. For example, " about " may mean one or more standard deviations, or within 30%, 20%, 10% or 5% of the stated value.

Unless otherwise defined, all terms (technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Also, terms such as those defined in commonly used dictionaries should be construed in the context of the related art and in the context of the present application, and should be construed in an ideal or overly formal sense, unless otherwise specifically defined herein It should not be.

Exemplary implementations are described herein with reference to cross-sectional views that are schematic representations of ideal implementations. As such, variations from the shape of the illustration as a result, such as, for example, manufacturing techniques and / or tolerances, should be expected. Thus, the implementations described herein should not be construed as limited to any particular shape of the area as illustrated herein, but should include variations in shape resulting from, for example, manufacture. For example, areas depicted or depicted as flat may typically have coarse and / or non-linear features. Moreover, the illustrated sharp angles can be rounded. Accordingly, the regions shown in the Figures are schematic in nature, and the shapes are not intended to illustrate the exact shape of the regions and are not intended to limit the scope of the claims.

The electrode laminate of the pre-solid secondary battery, which is a lamination of the positive electrode active material layer, the solid electrolyte layer, and the negative electrode active material layer, is pressed in the production of the all solid battery. Thus, the particles between each of the layers and between the layers can be dense and can be in contact with each other. The solid electrolyte layer may be of a thin film type.

<All solid state batteries>

The present inventors have intensively studied the problems of the all-solid secondary battery using metal lithium as the negative electrode active material, and consequently, the entire solid secondary battery according to the present embodiment has come to be considered. Hereinafter, the examination performed by the inventor will be described.

4 to 7, a conventional all-solid-state secondary battery 100 using metal lithium as a negative electrode active material includes a positive electrode active material layer 112, a negative electrode active material layer 122, and a solid electrolyte layer 130. 4 to 6 are views showing a configuration of a conventional all-solid-state secondary battery 100, and FIG. 7 is a SEM photograph of a cross section corresponding to FIGS. 5 to 6. The positive electrode active material layer 112 includes a positive electrode active material 112a and a solid electrolyte 112b. The solid electrolyte layer 130 includes a solid electrolyte 130a. The anode active material layer 122 is made of metal lithium.

A short circuit may occur when a crack 123 or the like is formed on the surface of the solid electrolyte layer 130. A situation in which a short circuit occurs will be described with reference to Fig. A gap 123 is formed in the solid electrolyte layer 130 so as to communicate with the upper and lower surfaces of the solid electrolyte layer 130 (for example, extending from the upper surface of the solid electrolyte layer 130 to the lower surface of the solid electrolyte layer 130) have. Metal lithium penetrates into the gap of the solid electrolyte layer 130 when the electrode laminate of the positive electrode active material layer 112, the negative electrode active material layer 122, and the solid electrolyte layer 130 is pressed. Since the clearance of the solid electrolyte layer 130 is communicated at the front and back surfaces of the solid electrolyte layer 130 (for example, extending from the upper surface of the solid electrolyte layer 130 to the lower surface of the solid electrolyte layer 130) Lithium could reach the positive electrode active material layer 112. Therefore, the entire solid secondary battery could be short-circuited. Further, even when the gap of the solid electrolyte layer 130 does not communicate with the front surface, the distance between the metal lithium and the cathode active material layer 112 that are different from the distance between the metal lithium penetrating into the gap and the cathode active material layer 112 . Therefore, a current may be concentrated at this portion (e.g., a gap) during charging, and a short circuit may occur.

If the interface between the positive electrode active material layer 112 and the solid electrolyte layer 130 is rough, a short circuit may occur. A situation in which a short circuit occurs will be further described with reference to Figs. 5 to 7. The interface B between the positive electrode active material layer 112 and the solid electrolyte layer 130 is coarse and a protrusion 112c is formed on the surface of the positive electrode active material layer 112. [ Therefore, at the time of charging, the distance between the protruding portion 112c and the negative electrode active material layer 122 becomes shorter than the distance between the other portion of the positive electrode active material layer and the negative electrode active material layer 122. [ Therefore, at the time of charging, the current is concentrated at this portion (the portion indicated by the frame A in Fig. 6). That is, a large current density flows in a portion indicated by the frame A. As a result, metal lithium is locally precipitated at the portion (for example, at the surface thereof), and short-circuiting occurs in some cases.

As described above, in the case where metal lithium is used as the negative electrode active material of the pre-solid secondary battery, a short circuit may occur. Therefore, the present inventors considered to increase the density of the solid electrolyte layer 130 and to flatten the interface between the positive electrode active material layer 112 and the solid electrolyte layer 130, in order to prevent a short circuit. When the density of the solid electrolyte layer 130 is high, the gap in the solid electrolyte layer 130 can be reduced and becomes small. Further, when the interface between the positive electrode active material layer 112 and the solid electrolyte layer 130 is flattened, the possibility that a large current flows locally is reduced. As a result, the inventors of the present invention have reached the top of the entire solid secondary battery according to the present embodiment. Hereinafter, this embodiment will be described in detail.

<2. Rating criteria: Configuration of all solid secondary battery>

Next, the configuration of the all-solid-state secondary battery 1 according to the present embodiment will be described with reference to Figs. 1a to 3. The entire solid secondary battery 1 has an anode 10, a cathode 20, and a solid electrolyte layer 30 as shown in Fig. In one embodiment, the cathode 20 of the pre-solid secondary battery includes a negative electrode active material layer 22 on the negative electrode collector 21. As shown in FIG. 1B, after the charging, the pre-solid secondary battery further includes a plating layer between the anode active material layer 22 and the anode current collector 21.

(2-1 anode)

The positive electrode 10 includes a positive electrode collector 11 and a positive electrode active material layer 12. As the positive electrode collector 11, for example, indium (In), copper (Cu), magnesium (Mg), stainless steel, titanium (Ti), iron (Fe), cobalt (Co) A plate or a thin body made of zinc (Zn), aluminum (Al), germanium (Ge), lithium (Li), or an alloy thereof. Combinations comprising at least one of the foregoing can be used. The positive electrode collector 11 may be omitted.

The positive electrode active material layer 12 may include a positive electrode active material 12a and a solid electrolyte 12b. In this case, the resistance between the positive electrode active material layer and the solid electrolyte layer can be lowered. The solid electrolyte 12b included in the anode 10 may be the same type as or similar to the solid electrolyte 12b included in the solid electrolyte layer 30. [ The details of the solid electrolyte 12b are described in detail in the section of the solid electrolyte layer 30. [

The cathode active material may be a cathode active material capable of reversibly intercalating and deintercalating lithium ions.

For example, the cathode active material may be at least one of composite oxides of lithium and metal selected from cobalt, manganese, nickel, and combinations thereof. In one embodiment, the cathode active material may be a compound represented by any of the following formulas: Li _a A _1-b B ¹ _b D ¹ _{2 where} 0.90 ≤ a ≤ 1.8, and 0 ≤ b ≤ 0.5 ); Li _a E _1-b B ¹ _b O _{2 -c} D ¹ _c wherein 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05; LiE _2-b B ¹ _b O _{4 -c} D ¹ _c wherein 0? B? 0.5, 0? C? 0.05; Li _a Ni _{1- b c} Co _b B ¹ _c D ¹ _? Wherein 0.90? A? 1.8, 0? B? 0.5, 0? C? 0.05, 0 <?? 2; Li _a Ni _{1- b c} Co _b B ¹ _c O _2-α F ¹ _α wherein 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 <α <2; Li _a Ni _{1- b c} Co _b B ¹ _c O _2-α F ¹ ₂ wherein 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 <α <2; Li _a Ni _1-bc Mn _b B ¹ _c D ¹ _? Wherein 0.90? A? 1.8, 0? B? 0.5, 0? C? 0.05, 0 <?? 2; Li _a Ni _1-bc Mn _b B ¹ _c O _2-α F ¹ _α wherein 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 <α <2; Li _a Ni _1-bc Mn _b B ¹ _c O _{2 -?} F ¹ ₂ wherein 0.90? A? 1.8, 0? B? 0.5, 0? C? 0.05, 0 <? Li _a Ni _b E _c G _d O ₂ wherein 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.9, 0 ≤ c ≤ 0.5, and 0.001 ≤ d ≤ 0.1; Li _a Ni _b Co _c Mn _d GeO ₂ wherein 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.9, 0 ≤ c ≤ 0.5, 0 ≤ d ≤ 0.5, and 0.001 ≤ e ≤ 0.1; Li _a NiG _b O ₂ (in the above formula, 0.90? A? 1.8, and 0.001? B? 0.1); Li _a CoG _b O ₂ wherein, in the above formula, 0.90? A? 1.8, and 0.001? B? 0.1; Li _a MnG _b O ₂ (in the above formula, 0.90? A? 1.8, 0.001? B? 0.1); Li _a Mn ₂ G _b O ₄ wherein, in the above formula, 0.90? A? 1.8, and 0.001? B? 0.1; QO _2; QS ₂ ; LiQS ₂ ; V ₂ O ₅ ; LiV ₂ O ₅ ; LiI ¹ O ₂ ; LiNiVO _4; Li _(3-f) J ₂ (PO ₄ ) ₃ (0? F? 2); Li _(3-f) Fe ₂ (PO ₄ ) ₃ (0? F? 2); In the formula of LiFePO ₄ may be used a compound represented by any one:

In the above formula, A is Ni, Co, Mn, or a combination thereof; B is Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, a rare earth element or a combination thereof; D is O, F, S, P, or a combination thereof; E is Co, Mn, or a combination thereof; F is F, S, P, or a combination thereof; G is Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, or combinations thereof; Q is Ti, Mo, Mn, or a combination thereof; I is Cr, V, Fe, Sc, Y, or a combination thereof; J is V, Cr, Mn, Co, Ni, Cu, or a combination thereof.

For example, the cathode active material may be lithium cobalt oxide (LCO), lithium nickel oxide, lithium nickel cobalt oxide, nickel cobalt aluminum lithium (NCA), nickel cobalt lithium manganese oxide (NCM) Lithium salt such as lithium manganate, lithium iron phosphate and the like, nickel sulfide, copper sulfide, sulfur, iron oxide, vanadium oxide and the like. Each of these cathode active materials may be used alone or in combination of two or more.

It is also preferable that the cathode active material is formed by including a lithium salt of a transition metal oxide having a layered halide salt structure among the above-mentioned lithium salts. Here, &quot; layered &quot; represents a thin sheet shape. The &quot; rock salt-like structure &quot; represents a sodium chloride-type structure that is one kind of crystal structure, specifically, a structure in which the face-centered cubic lattices formed by positive and negative ions are arranged so that the corners of the unit lattice are shifted by & .

As the lithium salt of the transition metal oxide having such a layered rock salt structure, for example, LiNi _x Co _y Al _z O ₂ (NCA) (0 <x <1, 0 <y <1, 0 <z <1 , and x + y + z = 1) , LiNi x 'Co y' Mn z 'O 2 (NCM) (0 <x'<1, 0 <y '<1, 0 <z'<1, and x ' + y '+ z' = 1), or a combination thereof.

In the case where the cathode active material comprises a lithium salt of a ternary system transition metal oxide having the layered rock salt type structure, the energy density and thermal stability of the entire solid secondary battery 1 can be improved.

The cathode active material may be covered by a coating layer. Here, it is preferable that the coating layer of this embodiment is any one as long as it is known as a coating layer of the positive electrode active material of the all-solid secondary battery. Examples of the coating layer include, for example, Li ₂ O-ZrO ₂ .

When the cathode active material is formed of a lithium salt of ternary transition metal oxide such as NCA or NCM and contains nickel (Ni) as the cathode active material, the capacity density of the pre-solid secondary battery 1 is increased, The metal elution in the cathode active material can be reduced. As a result, the entire solid secondary battery 1 according to the present embodiment can be improved in long-term stability and cycle characteristics in a charged state.

Examples of the shape of the positive electrode active material include particle shapes such as a true spherical shape and an elliptic spherical shape. The particle diameter of the cathode active material is not particularly limited and may be in a range applicable to the cathode active material of the conventional all-solid secondary battery. Also, the content of the cathode active material of the anode 10 is not particularly limited and may be a range applicable to the anode of a conventional all-solid-state secondary battery.

Additives such as a conductive agent, a binder, a filler, a dispersant, and an ion conductive agent may be appropriately added to the anode 10 in addition to the above-mentioned cathode active material and the solid electrolyte 12b.

Examples of the conductive agent that can be mixed into the anode 10 include graphite, carbon black, acetylene black, ketjen black, carbon fiber, metal powder, and the like. Examples of the binder that can be blended in the anode 10 include styrene butadiene rubber (SBR), polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, and the like. . As a filler, a dispersant, an ion conductive agent, and the like that can be mixed into the anode 10, known materials commonly used in the electrode of a lithium ion secondary battery can be used.

When the cathode active material layer 12 includes the cathode active material, the solid electrolyte 12b, and the binder, the cell capacity (capacity per unit cell) of the pre-solid secondary battery 1 can be increased.

For example, the binder can be selected from the group consisting of vinylidene fluoride / hexafluoropropylene copolymer, polyvinylidene fluoride (PVDF), polyacrylonitrile, polymethylmethacrylate, polytetrafluoroethylene, styrene butadiene rubber- A mixture thereof, and the like may be used, but not limited thereto, and any of them can be used as a binder in the art.

The relative density of the positive electrode active material layer 12 may be 60% or more. For example, the relative density of the cathode active material layer 12 is 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69% 78%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 73%, 73%, 74%, 75% , 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99%, less than 100% or less than 99.5%. From about 60% to about 99.5%, from about 65% to about 98%, or from about 70% to about 95%. The relative density used herein is given by the following equation (1).

&Quot; (1) &quot;

Relative density = (measured density / theoretical density) x 100%

The measured density can be determined by dividing the mass of the sample of material by the volume (e. G., Dividing the mass of the pellet material by volume). The theoretical density is the density of the material with zero porosity, which can be determined, for example, by calculating the density based on the crystal structure of the material, or by calculating the density based on the SEM analysis.

In this case, the battery characteristics of the entire solid secondary battery 1 are improved. Here, the relative density of the cathode active material layer 12 is a ratio of the density to the theoretical density of the cathode active material layer 12. The theoretical density of the positive electrode active material layer 12 is calculated according to the nominal density of each material constituting the positive electrode active material layer and the mass ratio of such material. In addition, the cross-section of the positive electrode active material layer 12 was observed with an SEM to measure the content of the positive electrode active material layer 12, and the content was determined as a relative density.

Here, as a method of setting the relative density of the cathode active material layer 12 to a value within the above range, a method of pressing the cathode active material layer 12 in the manufacturing process of the all-solid secondary battery 1 can be mentioned. In this embodiment, the positive electrode active material layer 12 is pressed before the positive electrode active material layer 12 is laminated on the solid electrolyte layer 30. 2 and FIG. 3) of the positive electrode active material layer 12 and the solid electrolyte layer 30, as will be described later in detail. The positive electrode active material layer 12 and the solid electrolyte layer 30 may have the relative density of the positive electrode active material layer 12, ) Can be flattened. Although the upper limit of the relative density is not particularly limited, it is preferably 95% or less when the positive electrode active material is a crystalline material such as a lithium salt of a transition metal oxide. If the relative density exceeds 95%, the cathode active material layer 12 may be cracked. When cracks are generated in the positive electrode active material layer 12, battery characteristics may be deteriorated. Further, when the positive electrode active material is amorphous such as sulfur, the relative density may be less than 100% and less than 99.5% due to the limitation of the performance of the production apparatus and the like.

(2-2 cathode)

The cathode 20 includes a cathode current collector 21 and a cathode active material layer 22. The anode current collector 21 may be made of any of indium, copper, magnesium, stainless steel, titanium, iron, cobalt, nickel, zinc, A plate or a thin body made of aluminum (Al), germanium (Ge), lithium (Li), or an alloy thereof. The anode current collector 21 may be omitted.

The negative electrode active material layer 22 includes metallic lithium. The anode active material layer 22 may include metal lithium or a metal active material other than metal lithium or metal lithium such as indium (In), aluminum (Al), tin (Sn), silicon (Si) ). &Lt; / RTI &gt; Preferably, the anode active material layer 22 may comprise metal lithium. As a result, the energy density of the entire solid secondary battery 1 can be improved.

In one embodiment, the anode active material layer 22 comprises carbon. Carbon may be amorphous or graphitic. Examples of carbon include but are not limited to Ketjen black, carbon black, graphite, carbon nanotubes, carbon fibers, mesoporous carbon, mesocarbon microbeads (MCMB), oil furnace black, But are not limited to, extra-conductive black, acetylene black, lamp black, non-graphitizing carbon, graphitizing carbon, cracked carbon, coke, Glassy carbon, and activated carbon. The coke includes a pitch coke, a needle coke, and a petroleum coke. Combinations comprising at least one of the foregoing can be used.

The negative electrode active material layer 22 may include a binder. Examples of the binder include, but are not limited to, styrene butadiene rubber (SBR), polytetrafluoroethylene, polyvinylidene fluoride, and polyethylene. Combinations comprising at least one of the foregoing can be used.

(2-3 solid electrolyte layer)

The solid electrolyte layer 30 is formed between the positive electrode 10 and the negative electrode 20 and includes a solid electrolyte 30a.

The solid electrolyte 30a is made of, for example, a sulfide-based solid electrolyte material. Examples of the sulfide-based solid electrolyte material include Li _7-a PS _6-a X _{a wherein} X is a halogen atom such as F, Cl, Br, I or a combination thereof, , A (0 <a <1), aLi ₂ S-bP ₂ S ₅ -cLiX wherein X is a halogen atom such as F, Cl, Br, I, 0 <b <1, 0 <c <1 and a + b + c = 1), aLi ₂ S-bP ₂ S ₅ -cLi ₂ O 1, 0 <c <1, 0 <d <1, and a + b + c = 1), aLi ₂ S-bP ₂ S ₅ -cLi ₂ O- 1 and a + b + c + d = 1), aLi ₂ S- (1-a) SiS ₂ (0 <a <1), aLi _{2 S} -bSiS ₂ -cLiI 1, 0 <c <1, and a + b + c = 1), aLi ₂ S-bSiS ₂ -cLiBr where 0 <a < _{c = 1), aLi 2 S} -bSiS 2 -cLiCl (0 <a <1, 0 <b <1, 0 <c <1, and a + b + c = 1) , aLi 2 S-bSiS 2 -cB ₂ S ₃ -dLiI (0 <a <1, 0 <b <1, 0 <c <1, 0 <d <1 and a + b + c + d = 1), aLi ₂ S-bSiS ₂ -cP _{2 S 5 -dLiI (0 <a <} 1, 0 <b <1, 0 <c <1, 0 <d <1 and a + b + c + d = 1), aLi 2 S- (1-a) B ₂ S ₃ (0 <a <1), aLi ₂ S-bP ₂ S ₅ -cZ _m S _n , wherein m and n are each independently a positive integer of 1 to 10 and Z is Ge, Zn, or Ga , 0 <a <1, 0 <b <1, 0 <c <1, and a + b + c = 1), aLi _{2 S- (1-a) GeS} 2 (0 <a <1), aLi 2 S-bSiS 2 -cLi 3 PO 4 (0 <a <1, 0 <b <1, 0 <c <1, and a b + c = 1), and aLi ₂ S-bSiS ₂ -cLi _P MO _q where p and q are each independently a positive integer of 1 to 10, 0 <a <1, 0 <b < C < 1, and a + b + c = 1, and M is P, Si, Ge, B, Al, Ga or In). Here, the sulfide-based solid electrolyte material is produced by treating the starting materials (for example, Li ₂ S, P ₂ S _5, etc.) by dissolving quenching or mechanical milling. Further, after this treatment, additional heat treatment can be performed. The solid electrolyte may be amorphous or crystalline and may be a mixed form thereof.

It is preferable to use at least one of sulfur (S), phosphorus (P) and lithium (Li) as a constituent element of the sulfide solid electrolyte material as the solid electrolyte 30a, particularly Li ₂ SP ₂ S ₅ It is more preferable to use the

Here, when a material containing Li ₂ SP ₂ S ₅ is used as the sulfide-based solid electrolyte material for forming the solid electrolyte _{30 a,} the mixed molar ratio of Li ₂ S and P ₂ S ₅ is, for example, Li ₂ S : P ₂ S ₅ = 50: 50 to 90: 10. Further, the solid electrolyte layer 30 may further include a binder. The binder contained in the solid electrolyte layer 30 includes, for example, styrene butadiene (SBR), polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, or a combination thereof . The binder in the solid electrolyte layer 30 may be the same as or different from the binder in the positive electrode active material layer 12. [

The relative density of the solid electrolyte layer 30 is 80% or more. For example, the relative density of the solid electrolyte layer 30 may be 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89% 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% or more, less than 100%, or 99.5% or less. For example, from about 80% to about 99.5%, or from about 85% to about 98%.

In this case, the gap in the solid electrolyte layer 30 becomes smaller and smaller. Therefore, occurrence of a short circuit becomes difficult. Here, the relative density of the solid electrolyte layer 30 is the density of the solid electrolyte layer 30 with respect to the theoretical density. The theoretical density of the solid electrolyte layer 30 can be calculated on the basis of the nominal density of each material constituting the solid electrolyte layer 30 and the mass ratio of each material and the cross section of the solid electrolyte layer 30 is observed by SEM The content of the solid electrolyte layer 30 can be measured and the content thereof can be made a relative density.

Here, as a method of setting the relative density of the solid electrolyte layer 30 to a value within the above-mentioned range, there is a method of pressing the solid electrolyte layer 30 during the manufacturing process of the all solid secondary battery 1. In this embodiment, before the solid electrolyte layer 30 is laminated on the negative electrode active material layer 22, the solid electrolyte layer 30 is pressed. Thereby, the relative density of the solid electrolyte layer 30 can be set to a value within the above range. The upper limit of the relative density is not particularly limited, but the relative density may be less than 100% or, for example, not more than 99.5% due to limitations on the performance of the production apparatus.

The thickness of the solid electrolyte layer 30 may be 100 m or less. For example, the thickness of the solid electrolyte layer 30 may be 100 μm, 95 μm, 90 μm, 85 μm, 80 μm, 75 μm, 70 μm, 65 μm, 60 μm, 55 μm, , But is not limited to, for example, from about 5 μm to about 100 μm, or from about 10 μm to about 90 μm. Thereby, the energy density of the entire solid secondary battery 1 can be increased. As a method of setting the thickness of the solid electrolyte layer 30 within the above-mentioned range, there is a method of pressing the solid electrolyte layer 30.

 (2-4 Interfacial State of the Cathode Active Material Layer and the Solid Electrolyte Layer)

In this embodiment, the interface B of the positive electrode active material layer 12 and the solid electrolyte layer 30 is flat as shown in Figs. 2 and 3. Specifically, the arithmetic average roughness Ra of the interface B is 1.0 占 퐉 or less. For example, the Ra may be less than or equal to 1.0, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, mu m, from about 0.05 mu m to about 0.9 mu m, from about 0.1 mu m to about 0.8 mu m, or from about 0.15 mu m to about 7 mu m. The maximum height Rz of the interface B may be 4.5 mu m or less. For example, the Rz may be 4.5, 4.4, 4.3, 4.2, 4.1, 4.0, 3.9, 3.8, 3.7, 3.6, , 3.4 μm, 3.3 μm, 3.2 μm, 3.1 μm, 3.0 μm, 2.9 μm, 2.8 μm, 2.7 μm, 2.6 μm, 2.5 μm, 2.4 μm and 2.3 μm and 2.2 1.1 m, 1.7 m, 1.6 m, 1.5 m, 1.4 m, 1.3 m, 1.2 m, 1.1 m, 1.0 m For example, from about 0.01 袖 m to about 4.5 袖 m, for example, from about 0.01 袖 m, 0.8 袖 m, 0.7 袖 m, 0.6 袖 m, 0.5 袖 m, 0.4 袖 m, 0.3 袖 m, From about 0.05 μm to about 4 μm, or from about 0.1 μm to about 3.5 μm to 0.01 μm to about 4.5 μm, from about 0.05 μm to about 4 μm, or from about 0.1 μm to about 3.5 μm, .

The arithmetic mean roughness (Ra) is statistically an arithmetic mean of the deviation of the roughness curve relative to the mean line. The maximum height roughness (Rz) is the vertical distance between two parallel lines passing through the highest point and the lowest point of the curve, parallel to the center line in the roughness curve at the interface.

Here, a method of measuring the arithmetic average roughness Ra and the maximum height roughness Rz of the interface B will be described with reference to FIG. 8 shows a cross-sectional SEM photograph of the vicinity of the interface B. Fig. First, an SEM photograph of the entire solid secondary battery 1 is obtained. Then, a portion near the interface B (for example, a portion shown in Fig. 8) is taken in a cross-sectional SEM photograph. This step may be omitted. Subsequently, the cathode active material 12a which is in contact with the solid electrolyte layer 30 is extracted from the cross-sectional SEM photograph. Subsequently, a point P closest to the solid electrolyte layer 30 is extracted from the positive electrode active material 12a. Then, the roughness curve passing through the point P is measured, and the arithmetic mean roughness Ra and the maximum height roughness Rz are measured based on the roughness curve. Specific measurements can be performed using ImageJ, the analysis software of the National Institutes of Health (NIH, http://imagej.nih.gov/ij/). In the embodiments described later, the arithmetic average roughness Ra and the maximum height roughness Rz by this method were measured. The roughness curve represents the interface B described above.

In the present embodiment, since the arithmetic average roughness Ra of the interface B is 1.0 占 퐉 or less, current flows more uniformly in the solid electrolyte layer 30 at the time of charging the entire solid secondary battery 1. As a result, metal lithium is uniformly deposited on the negative electrode active material layer 22, and short-circuiting is less likely to occur.

In addition, even when the arithmetic average roughness Ra is 1.0 占 퐉 or less, the maximum height roughness Rz may become large. Then, there is a possibility that the current is concentrated in a portion where the maximum height illumination Rz is large. Therefore, it is preferable that the maximum height illuminance Rz is 4.5 m or less. As a result, the current flows more uniformly in the solid electrolyte layer 30 when the entire solid secondary battery 1 is charged. The smaller the arithmetic average roughness Ra and the maximum height roughness Rz are, the smaller the arithmetic mean roughness Ra and the maximum height roughness Rz are, so the lower limit value is not particularly limited. However, the arithmetic average roughness Ra may be 0.2 탆 or more, and the maximum height roughness Rz may be 1.5 탆 or more because of restrictions on the performance of the manufacturing apparatus and the like.

&Lt; 3. Manufacturing method of lithium ion secondary battery >

Next, a method of manufacturing the all-solid-state secondary battery 1 according to the embodiment will be described. The pre-solid secondary battery 1 according to the present embodiment can be manufactured by manufacturing each of the anode 10, the cathode 20 and the solid electrolyte layer 30, and laminating the respective layers described above. The anode 10, the cathode 20 and the solid electrolyte layer 30 can be manufactured by a known method.

(3-1 anode manufacturing process)

The cathode active material can be produced by a known method. The prepared cathode active material, the solid electrolyte prepared by the method described below, and various additives are mixed and added to a non-polar solvent to form a slurry or paste. The anode 10 can be obtained by coating the obtained slurry or paste on the cathode current collector 11, followed by drying and rolling. The positive electrode 10 can be manufactured by compaction molding a mixture of the positive electrode active material and various additives in the form of a pellet without using the positive electrode collector 11.

 (3-2 cathode manufacturing process)

The cathode 20 is manufactured by laminating a metal foil (for example, metallic lithium in the form of a metal foil) as the anode active material layer 22 on the anode current collector 21.

By using a metal lithium foil as the negative electrode active material layer, it is easy to manufacture a high capacity battery.

 (3-3. Solid electrolyte layer production process)

The solid electrolyte layer 30 may be made of a solid electrolyte formed from a sulfide-based solid electrolyte material.

First, the starting material is treated by melt quenching or mechanical milling.

For example, when the melt quenching method is used, a predetermined amount of a starting material (for example, Li ₂ S, P ₂ S _5, etc.) is mixed and a pellet is reacted in a vacuum at a predetermined reaction temperature, Thereby preparing a sulfide-based solid electrolyte material. The reaction temperature of the mixture of Li ₂ S and P ₂ S ₅ is preferably 400 ° C. to 1000 ° C., and more preferably 800 ° C. to 900 ° C. The reaction time is preferably 0.1 hour to 12 hours, more preferably 1 hour to 12 hours. Next, the cooling temperature of the reactant is usually 10 ° C or lower, preferably 0 ° C or lower, and the cooling rate is usually 1 ° C / sec to 10000 ° C / sec, preferably 1 ° C / sec to 1000 ° C / sec.

When mechanical milling is used, a starting material (for example, Li ₂ S, P ₂ S _5, etc.) is stirred and reacted using a boehmite or the like to prepare a sulfide-based solid electrolyte material. The stirring speed and stirring time of the mechanical milling method are not particularly limited. However, the faster the stirring speed, the faster the production rate of the sulfide-based solid electrolyte material can be. Therefore, the longer the stirring time is, the faster the starting material for the sulfide-based solid electrolyte material The conversion rate can be increased.

Thereafter, the mixed raw material obtained by the melt quenching method or the mechanical milling method is subjected to heat treatment at a predetermined temperature and then pulverized to prepare a solid electrolyte in a particulate state. When the solid electrolyte has a glass transition point, it may become amorphous to crystalline by heat treatment.

Subsequently, the solid electrolyte obtained by the above method is formed by a known film forming method such as aerosol deposition method or cold spray method sputtering method, for example, so that the solid electrolyte layer 30 is formed . Further, the solid electrolyte layer 30 is made by pressing the solid electrolyte particles together. The solid electrolyte layer 30 may be prepared by mixing a solid electrolyte, a solvent, and a binder, and applying, drying, and pressing the solid electrolyte layer 30. The specific content of the film-forming method can be determined by a person skilled in the art without undue experimentation and is therefore not further described for the sake of clarity.

 (4. Press process)

Then, a press process is performed. The press process of this embodiment is divided into a preliminary press process and a main press process.

 (4-1. Preliminary Pressing Process)

In the preliminary press process, the positive electrode active material layer and the solid electrolyte layer are pressed in advance. Specifically, the preliminary pressing process includes a pressing process of the positive electrode active material layer and a pressing process of the solid electrolyte layer.

 (4-1-1. Cathode Active Material Layer Pressing Process)

In the pressing process of the positive electrode active material layer, the positive electrode active material layer 12 is pressed before the positive electrode active material layer 12 is laminated on the solid electrolyte layer 30. Here, the positive electrode active material layer 12 is pressed together with the positive electrode collector 11. Thereby, the surface of the cathode active material layer 12 can be flattened, but the arithmetic average roughness Ra and the maximum height roughness Rz of the interface B can be set within the above-mentioned range. The arithmetic average roughness Ra and the maximum height roughness Rz of the interface B can be set to values within the range described above even if the solid electrolyte layer 30 is laminated on the positive electrode active material layer 12 and then these laminated bodies are pressed. Can not.

A method of pressing the positive electrode active material layer 12 is not particularly limited, and a press method used for manufacturing a conventional all-solid secondary battery is sufficient. For example, the cathode active material layer 12 can be pressed by a roll press or the like.

The specific press pressure may vary depending on the press apparatus, the material of the positive electrode active material layer 12, and the like. The arithmetic average roughness Ra and the maximum height roughness Rz of the interface B tend to be lower as the press pressure is higher. The press pressure may be adjusted so as to be within the range.

The positive electrode active material layer can increase the relative density of the active material through a preliminary pressing process. In addition, the arithmetic surface roughness of the anode surface including the cathode active material can be reduced to reduce the interfacial resistance.

 (4-1-2. Solid Electrolyte Layer Pressing Process)

In the solid electrolyte layer press step, the solid electrolyte layer 30 is pressed before the solid electrolyte layer 30 is laminated on the negative electrode active material layer 22. Thereby, the relative density of the solid electrolyte layer 30 can be set to a value within the above-mentioned range. In addition, the relative density of the solid electrolyte layer 30 can not be set within the above-described range even if the solid electrolyte layer 30 is laminated on the negative electrode active material layer 22 and these laminated bodies are pressed. The solid electrolyte layer press process is classified into the following three types. Any method can achieve the effect of the present embodiment, and the second method is most effective among them.

A specific pressing method for carrying out the solid electrolyte layer press step is not particularly limited, and it is sufficient that the conventional press method used in the production of a suitable all-solid secondary battery. For example, the solid electrolyte layer 30 can be pressed by a roll press or the like.

The specific press pressure may vary depending on the material of the press apparatus, the solid electrolyte layer 30, and the like. However, since the relative density of the solid electrolyte layer 30 tends to increase as the press pressure increases, the press pressure may be adjusted so that the relative density of the solid electrolyte layer 30 is within the above-mentioned range.

(4-1-2-1. First press method)

The first pressing method includes a step of pressing the solid electrolyte layer alone (" solid electrolyte layer single pressing step "). The solid electrolyte layer 30 is pressed before the solid electrolyte layer 30 is laminated on the pressed positive electrode active material layer 12 in the positive electrode active material layer press process in the solid electrolyte layer single press process. Therefore, in the first pressing method, the solid electrolyte layer 30 is pressed before the solid electrolyte layer 30 is laminated on the negative electrode active material layer 22. Thereby, the relative density of the solid electrolyte layer 30 can be set to a value within the above-mentioned range. In addition, in the first pressing method, the solid electrolyte layer 30 is pressed alone before the solid electrolyte layer 30 is laminated on the positive electrode active material layer 12. Therefore, the relative density of the solid electrolyte layer 30 can be more reliably increased. In addition, in the present press process to be described later, since the pressed solid electrolyte layer 30 is laminated on the positive electrode active material layer 12, the arithmetic average roughness Ra and the maximum height roughness Rz of the interface B can be more reliably reduced And the first press method does not involve the first intermediate laminate press step, which will be described later, so that the relative density of the solid electrolyte layer 30 tends to be somewhat lowered as compared with the second press method.

 (4-1-2-2 second press method)

The second press method includes the above-described solid electrolyte layer single press process and the first intermediate laminate press process. The solid electrolyte layer 30 is pressed before the solid electrolyte layer 30 is laminated on the pressed positive electrode active material layer 12 in the positive electrode active material layer press process in the solid electrolyte layer single press process. In the first intermediate laminate press process, the first intermediate laminate which is a laminate of the solid electrolyte layer 30 pressed in the solid electrolyte layer single press process and the positive electrode active material layer 12 pressed in the positive electrode active material layer press process is pressed .

In the second pressing method, the solid electrolyte layer 30 is pressed before the solid electrolyte layer 30 is laminated on the negative electrode active material layer 22. Thereby, the relative density of the solid electrolyte layer 30 can be set to a value within the above-mentioned range. In addition, in the second pressing method, the solid electrolyte layer 30 is pressed alone before the solid electrolyte layer 30 is laminated on the positive electrode active material layer 12. Therefore, not only the relative density of the solid electrolyte layer 30 can be more reliably increased, but also the arithmetic average roughness Ra and the maximum height roughness Rz of the interface B can be more reliably reduced.

 (4-1-2-3 third press method)

The third pressing method presses the second intermediate laminate which is a lamination of the solid electrolyte layer 30 and the positive electrode active material layer 12 pressed in the positive electrode active material layer press process. The third pressing method is a method excluding the solid electrolyte layer single pressing step in the second pressing method.

In the third pressing method, the solid electrolyte layer 30 before being pressed is laminated on the positive electrode active material layer 12. Therefore, the solid electrolyte layer 30 having a rough surface may be laminated on the positive electrode active material layer 12. However, the solid electrolyte layer 30 is soft compared to the positive electrode active material layer 12, and the surface shape of the solid electrolyte layer 30 may depend on the surface shape of the positive electrode active material layer 12. [ Therefore, the arithmetic average roughness Ra of the interface B and the maximum height roughness Rz are the above-mentioned range values. As a result, the arithmetic average roughness Ra and the maximum height roughness Rz of the interface B tend to be somewhat higher than those of the first press and the second press method because the solid electrolyte layer single press step is omitted. However, since the solid electrolyte layer 30 is pressed before the solid electrolyte layer 30 is laminated on the negative electrode active material layer 22, the same effects as those of the first and second pressing methods are obtained.

It is preferable that the relative density of the positive electrode active material layer 12 and the solid electrolyte layer 30 is set to a value (60% or 80% or more) in the above-mentioned numerical range at the end of the preliminary pressing process.

(4-2. Pressing Process)

In this pressing step, the pressed positive electrode active material layer 12 (i.e., the positive electrode 10), the solid electrolyte layer 30, and the negative electrode active material layer 22 (i.e., the negative electrode 20) Thereby producing an electrode laminate. Subsequently, the electrode laminate is pressed. Through the above steps, the entire solid secondary battery 1 is manufactured. A specific pressing method for carrying out the pressing process is not particularly limited, and a press method used for manufacturing a conventional all-solid secondary battery is sufficient. For example, the present pressing process can be performed by a roll press or the like.

In one embodiment, a pre-solid secondary battery including a plating layer between the anode current collector and the anode active material layer includes the steps of: providing a cathode including a cathode active material layer; Disposing a solid electrolyte layer on the positive electrode; Disposing a negative electrode on the solid electrolyte layer, wherein the negative electrode includes a negative electrode collector and a negative electrode active material layer disposed on the negative electrode collector, wherein the negative electrode active material layer comprises carbon; And providing a voltage between the anode and the cathode to form a plating layer between the anode active material layer and the anode current collector.

[Example]

 (1. Example 1)

Next, an embodiment of the present embodiment will be described. In Example 1, all solid secondary batteries were manufactured by the following steps.

 (1-1. Anode manufacture)

_{LiNi 0. 8 Co 0. 15 Al 0.} 5 O 2 (NCA) 3 -component powder, a sulfide-based solid electrolyte Li ₂ SP ₂ S ₅ (molar ratio 75: 25), a crystalline powder, and vapor-grown as the conductive material as a cathode active material The carbon fiber powders were weighed in a weight ratio of 60: 35: 5 and mixed using a revolving mixer.

Next, a dehydrated xylene solution in which SBR was dissolved as a binder was added to the mixed powder so that the SBR was 5.0 mass% with respect to the total mass of the mixed powder, thereby producing a first mixture. Further, dehydrated xylene for viscosity adjustment was added to the obtained primary mixture in an appropriate amount to produce a secondary mixture. Further, in order to improve the dispersibility of the mixed powder, a zirconia ball having a diameter of 5 mm was introduced into the second mixture in such an amount that the space, the mixed powder and the zirconia ball accounted for 1/3 of the total volume of the kneading container, respectively . The thus-produced tertiary mixture was charged into a rotating, stirring, mixer, and stirred at 3000 rpm for 3 minutes to produce a cathode active material layer coating liquid

Subsequently, an aluminum foil current collector having a thickness of 20 mu m was prepared as a cathode current collector, a cathode current collector was placed in a tabletop screen printing machine, and a metal mask having a diameter of 2.0 cm x 2.0 cm and a thickness of 150 mu m was used Thereby coating the positive electrode active material layer coating liquid on the sheet. Thereafter, the sheet coated with the positive electrode active material layer coating solution was dried on a hot plate at 60 DEG C for 30 minutes, followed by vacuum drying at 80 DEG C for 12 hours. Thus, a positive electrode active material layer was formed on the positive electrode current collector. The total thickness of the cathode current collector and the cathode active material layer after drying was around 165 탆.

(1-2. Preparation of Solid Electrolyte Layer)

A dehydrated xylene solution in which SBR was dissolved in a crystalline powder of Li ₂ SP ₂ S ₅ (molar ratio 75:25) as a sulfide-based solid electrolyte was added so that SBR was 2.0 mass% with respect to the total mass of the mixed powder, Generated. Further, dehydrated xylene for viscosity adjustment was added to the obtained primary mixture in an appropriate amount to produce a secondary mixture. Further, in order to improve the dispersibility of the mixed powder, a zirconia ball having a diameter of 5 mm was introduced into the third mixture in an amount occupying 1/3 of the space, the composite powder, and the zirconia ball, respectively, relative to the total volume of the kneading vessel. The thus-produced tertiary mixture was charged into a rotating, stirring, and a mixer, and stirred at 3000 rpm for 3 minutes to produce an electrolyte layer coating solution.

The substrate of polyethylene terephthalate (PET) was placed on a desktop screen printer, and the electrolyte layer coating liquid was coated on the PET substrate using a metal mask having a hole diameter of 2.5 cm x 2.5 cm and a thickness of 300 m. Thereafter, it was dried with a hot plate at 40 DEG C for 10 minutes, followed by vacuum drying at 40 DEG C for 12 hours. Thus, a solid electrolyte layer was formed. The total thickness of the solid electrolyte layer after drying was around 180 탆.

 (1-3 cathode manufacturing)

A nickel foil current collector having a thickness of 20 mu m was provided as an anode current collector, and a metal lithium foil having a width of 2.2 cm x 2.2 cm and a thickness of 30 mu m was bonded to the anode current collector to prepare a cathode.

 (Based on 1-4 points: Preparation of all solid secondary batteries)

In Example 1, the preliminary press process of the following process was carried out. That is, the positive electrode was pressed at a pressure of 10 tons by a uniaxial pressing machine. Thus, the positive electrode active material layer press step was carried out. The bulk density of the positive electrode active material layer after pressing was 2.23 g / cc. The pressed positive electrode active material layer was cut with a toson knife having a diameter of 10 mm and its height and mass were measured. The bulk density of the cathode active material layer was calculated by dividing the mass of the cut electrode layer by volume.

Subsequently, a solid electrolyte layer press step was performed. In Example 1, the second method was adopted as the solid electrolyte layer forming step. Specifically, the solid electrolyte layer was pressed at a pressure of 10 tons by a uniaxial pressing machine (solid electrolyte layer single pressing step). The solid electrolyte layer was pressed together with the PET substrate. The bulk density of the solid electrolyte layer after pressing was 1.53 g / cc. The bulk specific gravity of the solid electrolyte layer was calculated by the same method as the method of calculating the bulk density of the cathode active material.

Subsequently, the positive electrode was cut with a Thomson knife having a diameter of 11 mm, and the solid electrolyte layer and the positive electrode on the PET substrate were laminated so that the solid electrolyte layer and the positive electrode active material layer were opposed to each other. Subsequently, the solid electrolyte layer and the anode were bonded by a dry lamination method using a roll press machine with a roll spacing of 150 mu m. Thus, a first intermediate laminate was produced. Subsequently, the first intermediate laminate was pressed by a uniaxial press at a pressure of 10 tons (first intermediate laminate press process). The bulk density of the cathode active material layer after pressing was 2.27 g / cc, and the bulk density of the solid electrolyte layer was 1.56 g / cc. The thickness of the solid electrolyte layer was 90 mu m. A preliminary pressing step by the above process was performed.

Then, the relative density of the positive electrode active material layer and the solid electrolyte layer was calculated based on the bulk density after the preliminary pressing process. Specifically, the nominal densities of NCA, Li ₂ SP ₂ S ₅ (molar ratio 75:25) crystalline powder and the conductive agent were 4.6 g / cc, 1.8 g / cc and 2.1 g / cc, respectively. Therefore, the theoretical density of the cathode active material layer was 3.50 g / cc (= 4.6 x 0.6 + 1.8 x 0.35 + 2.1 x 0.05) and the theoretical density of the solid electrolyte layer was 1.8 g / cc. Therefore, the relative density of the positive electrode active material layer was 64.9% (= 2.27 / 3.50) and the relative density of the solid electrolyte layer was 86.7% (= 1.56 / 1.8). In this embodiment, in order to simplify the calculation, the binder is not considered in the calculation of the theoretical density. The binder has a smaller usage than the other components, so that it does not affect the result without considering the binder. If the relative density at this point in time is a value in the above-described numerical value range, the relative density after the pressing process inevitably becomes the above-described numerical range value.

Then, the arithmetic average roughness Ra and the maximum height roughness Rz of the interface B were measured in the following steps. That is, the cross-section of the first intermediate laminate was obtained by cutting using ion milling (E-3500, Hitachi High-Technologies Co., Ltd.). Then, the cross section was observed with an FE-SEM (JEOL-JSM-7800F, Japan Electronics), and a cross-sectional SEM image was obtained. 3 is a cross-sectional SEM image of Example 1. Fig. Then, the arithmetic average roughness Ra and the maximum height roughness Rz of the interface B were measured by the above-described method.

Subsequently, the negative electrode was cut with a Thomson knife having a diameter of 13 mm, and the first intermediate laminate and the negative electrode were laminated so that the solid electrolyte layer and the negative electrode active material layer were opposed to each other. Subsequently, the electrode laminate was pressed at a pressure of 3 tons by a uniaxial pressing machine. That is, this press process was performed. The thickness of the solid electrolyte layer after the pressing process was 85 占 퐉.

Subsequently, after the pressing process, the electrode laminate was placed in an aluminum laminate film having terminals attached thereto and evacuated to a vacuum of 100 Pa using a vacuum apparatus. Subsequently, the electrode laminate was enclosed in the laminate film using a heat seal. As a result, all solid secondary batteries (test cells) were produced.

 (1-5 short circuit)

The short circuit of the test cell was judged by the open circuit voltage of the test cell. More specifically, the closed circuit voltage of the test cell was measured, and it was judged that a short circuit occurred when the voltage was 2.4 V or less. The short circuit life test was not carried out for the following cycle life test.

 (1-6 cycle life test)

The resulting test cell was charged and discharged at a constant current of 0.13 mA at a constant current of 45 DEG C to 4.0 V and discharged at 0.13 mA until the discharge end voltage reached 2.5 V. This cycle was repeated 50 times. The discharge capacity ratio at the 50th cycle with respect to the discharge capacity (initial capacity) of the first cycle was defined as the retention rate of the discharge capacity. The measurement of the discharge capacity is in accordance with TOSCAT-3100 of the Oriental System insect-and-discharge evaluation apparatus. The retention rate of the discharge capacity is a parameter showing the cycle characteristics. The larger the value, the better the cycle characteristics. The properties and evaluation results of the respective examples and comparative examples are summarized in Table 1. In one embodiment, the capacity retention rate of the entire solid state secondary cell after 50 charging / discharging cycles may exceed about 75%.

 (2. Example 2)

The same test as in Example 1 was conducted except that the third method was carried out in the solid electrolyte layer press step. Specifically, in Example 2, the following preliminary pressing step was carried out.

The positive electrode 10 was pressed by a uniaxial press at a pressure of 10 tons (positive electrode active material layer pressing step). The bulk density of the positive electrode active material layer after pressing was 2.26 g / cc.

Subsequently, the positive electrode was cut with a Thomson knife having a diameter of 11 mm, and the solid electrolyte layer and the positive electrode on the PET substrate were laminated so that the solid electrolyte layer and the positive electrode active material layer were opposed to each other. Subsequently, the solid electrolyte layer and the anode were bonded by a dry lamination method using a roll press machine having a roll spacing of 150 mu m. Thus, a second intermediate laminate was produced. Subsequently, the second intermediate laminate was pressed by a uniaxial press at a pressure of 10 tons (second intermediate laminate press process). The bulk density of the positive electrode active material layer after pressing was 2.29 g / cc, and the bulk density of the solid electrolyte layer was 1.55 g / cc. A preliminary pressing step by the above process was performed. Thereafter, the same process as in Example 1 was carried out. In addition, the arithmetic average roughness Ra and the maximum height roughness Rz of the interface B were measured using the second intermediate laminate after the pre-press. The results are summarized in Table 1.

 (3. Example 3)

The same test as in Example 1 was carried out except that the first method was performed in the solid electrolyte layer press step. Specifically, in Example 3, the following preliminary pressing step was carried out.

That is, the positive electrode 10 was pressed by a uniaxial press at a pressure of 10 tons (positive electrode active material layer pressing step). The volume specific gravity of the positive electrode active material layer after pressing was 2.24 g / cc.

Subsequently, the solid electrolyte layer was pressed at a pressure of 10 tons by a uniaxial pressing machine (solid electrolyte layer single pressing step). The solid electrolyte layer was pressed together with the PET substrate. The bulk density of the solid electrolyte layer after pressing was 1.53 g / cc. A preliminary pressing step by the above process was performed.

Subsequently, the positive electrode and negative electrode were cut with a Thomson knife used in Example 1, and the positive electrode, the solid electrolyte layer and the negative electrode were laminated so that the solid electrolyte layer and each active material layer were opposed to each other. Subsequently, the electrode laminate was pressed at a pressure of 3 tons by a uniaxial pressing machine. That is, this press process was performed. Thereafter, the same test as in Example 1 was carried out. The arithmetic average roughness Ra and the maximum height roughness Rz of the interface B were measured using the electrode laminate after the pressing.

 (4. Example 4)

The same test as in Example 1 was carried out except that the press pressure of the first intermediate laminate press process was changed to 15 tons

 (5. Example 5)

The same test as in Example 1 was conducted except that the press pressure of the positive electrode active material layer press process and the solid electrolyte layer single press process was changed to 7 tons.

(6. Example 6)

The same test as in Example 2 was conducted except that the pressing pressure in the pressing process of the positive electrode active material layer was changed to 7 tons.

(7. Example 7)

In Example 7, the positive electrode active material layer and the solid electrolyte layer were formed by the following steps. That is, NCA ternary system powder, Li ₂ SP ₂ S ₅ (molar ratio 75:25) amorphous powder as a sulfide solid electrolyte, and vapor phase grown carbon fiber powder as a conductive agent were measured at a mass ratio of 90: 7: 3 A cathode active material layer was produced by the same process as in Example 4. A solid electrolyte layer was prepared in the same manner as in Example 4, except that amorphous powder of Li ₂ SP ₂ S ₅ (molar ratio 75:25) was used as the sulfide-based solid electrolyte.

Further, the following steps were carried out in the preliminary pressing step. That is, the positive electrode was pressed under a vacuum by a uniaxial pressing machine at a pressure of 15 tons (positive electrode active material layer pressing step). Subsequently, the solid electrolyte layer was pressed under a vacuum by a uniaxial pressing machine at a pressure of 15 tons (solid electrolyte layer single pressing step). Thereafter, the same step as in Example 4 (specifically, the first intermediate laminate press step) was carried out. A preliminary pressing step of the above process was performed. The bulk density of the positive electrode active material layer after the preliminary pressing process was 3.82 g / cc. The bulk density of the solid electrolyte layer after the preliminary pressing was 1.77 g / cc. The theoretical density of the cathode active material layer at this time was 4.33 g / cc (= 4.6x0.9 + 1.8x0.07 + 2.1x0.03) and the relative density was 88.2% (= 3.82 / 4.33). The theoretical density of the solid electrolyte layer was 98.3% (= 1.77 / 1.8). The process other than the above was the same as in Example 4.

(8. Example 8)

The same experiment as in Example 1 was carried out except that the negative electrode layer was produced by the following process. A nickel foil having a thickness of 20 mu m was prepared as a negative electrode current collector. As the negative electrode active material, an acetylene black powder (AB) having a primary particle diameter of 35 nm was prepared. 2 g of AB was placed in a container, and an NMP solution in which PVdF as a binder was dissolved was added so that PVdF was 3.0% by mass with respect to the total mass of the mixed powder to generate a primary mixed solution. To this primary mixed solution, an appropriate amount of NMP was added to adjust the viscosity to generate a secondary mixed solution. The secondary mixed solution thus produced was charged in a revolving charge mixer and stirred at 2000 rpm for 5 minutes to generate a negative electrode coating solution.

 The slurry was applied on a Ni foil using a blade coater, dried on a hot plate at 100 占 폚 for 30 minutes, and then vacuum-dried at 180 占 폚 for 12 hours. The negative electrode layer was produced by the above-described steps. The total thickness of the negative electrode collector and the negative electrode active material layer after drying was about 30 탆. The entire solid battery prepared in Example 8 was charged only once under the same conditions as in Example 1.

Thereafter, the battery was disassembled in a dry atmosphere, and the cross section of the entire solid battery was polished by an ion milling apparatus and observed by SEM. As a result, lithium was precipitated at the interface between the nickel foil and the AB layer by charging.

 (9. Comparative Example 1)

The same test as in Example 1 was conducted except that the positive electrode active material layer press process and the solid electrolyte layer single press process were not performed. 7 shows a cross-sectional SEM photograph used for measurement of the arithmetic mean roughness (Ra) and the maximum height roughness (Rz) of Comparative Example 1. Fig.

(10. Comparative Example 2)

The same test as in Example 1 was carried out except that all press pressures in the preliminary press process were changed to 3 tons.

(11. Comparative Example 3)

The same test as in Example 1 was conducted except that the positive electrode active material layer pressing step was not performed.

(12. Comparative Example 4)

The same test as in Example 3 was conducted except that the positive electrode active material layer pressing step was not performed.

(13. Comparative Example 5)

The same test as in Example 3 was carried out except that the solid electrolyte layer single press process was not performed.

 (14. Comparative Example 6)

The same test as in Comparative Example 1 was carried out except that a metal mask having a thickness of 600 mu m was used to produce the solid electrolyte layer.

(15. Comparative Example 7)

The same test as in Example 3 was carried out except that the preliminary press process was not carried out. That is, in Comparative Example 7, only this pressing step was performed. The bulk density of each layer, the arithmetic average roughness (Ra) of the interface B, and the maximum height roughness (Rz) were measured using the electrode laminate after the press.

(16. Comparative Example 8)

A test similar to that of Example 8 was conducted except that the positive electrode active material layer press process and the solid electrolyte layer single press process were not performed.

 (17. Referential Example 1)

The same test as in Comparative Example 1 was carried out except that a metal mask having a thickness of 1200 mu m was used to produce the solid electrolyte layer.

(18, Reference Example 2)

The same test as in Comparative Example 1 was carried out except that the negative electrode was produced by the following process. Namely, graphite powder (vacuum dried at 80 ° C for 24 hours) and polyvinylidene fluoride (PVdF) as a binder were weighed at a mass ratio of 95.0: 5.0 as the negative electrode active material. These materials and an appropriate amount of N-methyl-2-pyrrolidone (NMP) were charged into a rotating, stirring, and a mixer, stirred at 3000 rpm for 3 minutes and then subjected to a defoaming treatment for 1 minute to produce a negative electrode active material coating solution.

Next, a nickel foil collecting member having a thickness of 20 mu m was prepared as a negative electrode current collector, and a nickel mask collector having a hole diameter of 2.2 cm x 2.2 cm and a thickness of 250 mu m was used to coat the nickel collector. The sheet coated with the negative electrode active material coating solution was placed in a dryer heated at 80 캜 and dried for 15 minutes. In addition, the dried sheet was vacuum-dried at 80 DEG C for 24 hours. This produced the cathode. The thickness of the negative electrode was about 140 탆.

 (17, Reference Example 3)

In Reference Example 3, a nonaqueous electrolyte secondary battery was produced by the following steps. Thereafter, the cycle life test was carried out in the same manner as in Example 1.

 (17-1 Production of anode)

NCA ternary system powder as a positive electrode active material and acetylene black as a conductive agent were weighed at a weight ratio of 97: 3 and mixed. Next, an NMP solution in which PVdF was dissolved as a binder was added to the mixed powder so that PVdF was 3.0% by mass with respect to the total mass of the mixed powder, thereby producing a primary mixture. In order to adjust the viscosity, an appropriate amount of NMP was added to the obtained primary mixture to produce a secondary mixture. The resulting secondary mixture was charged into a rotating, orbital, mixer, and stirred at 2000 rpm for 3 minutes to produce a positive electrode coating solution.

Subsequently, an aluminum foil current collector having a thickness of 20 mu m was prepared as a cathode current collector, a cathode current collector was placed in a tabletop screen printer, and a cathode active material coating liquid was coated on the sheet using a metal mask having a hole diameter of 2.0 cm x 2.0 cm and a thickness of 150 mu m Coated. Thereafter, the sheet coated with the positive electrode active material coating solution was dried with a hot plate at 100 DEG C for 30 minutes, followed by vacuum drying at 180 DEG C for 12 hours. Thus, a positive electrode active material layer was formed on the positive electrode current collector. The total thickness of the cathode current collector and the cathode active material layer after drying was around 120 탆.

The first press molding was performed at a pressure of 3 tons using a uniaxial press machine for the anode. The density of the anode after compression was 2.33 g / cc. The anode was cut with a Thomson blade of 11 mm in diameter.

(17-2 Production of negative electrode)

A copper foil collector having a thickness of 20 mu m was prepared as a negative electrode current collector, and metal lithium gold having a thickness of 30 mu m was bonded to produce a negative electrode. The cathode was cut with a Thomson blade of 13 mm in diameter.

(17-3 Production of non-aqueous electrolyte secondary battery)

A porous polyethylene film (φ 15.5 mm, thickness 12 μm) was used as the separation membrane. A separator was interposed between the positive electrode and the negative electrode to produce an electrode laminate. The electrode laminate was processed into a 2032 coin half cell.

Subsequently, lithium hexafluorophosphate (LiPF ₆ ) was dissolved in a nonaqueous solvent in which ethylene carbonate and dimethyl carbonate were mixed at a volume ratio of 3: 7 so as to have a concentration of 1.3 mol / L to prepare an electrolyte Respectively. The prepared electrolyte was injected into a 2032 coin cell half cell to impregnate the electrolyte with a separator. Thus, a nonaqueous electrolyte secondary battery was produced.

The nominal densities of NCA and acetylene black were 4.6 g / cc and 2.1 g / cc, respectively. Therefore, the theoretical density of the cathode active material layer was 4.53g / cc (= 4.6x0.97 + 2.1x0.03) and the relative density was 51.4% (= 2.33 / 4.53).

According to Table 1, in Examples 1 to 7, the requirements of the present embodiment are satisfied, short-circuiting is not caused immediately after fabrication, and the retention ratio is also high (in other words, short-circuiting is difficult to occur). In Example 7, an amorphous solid electrolyte was used, and the initial capacity was slightly lower than in the other Examples. However, the value was not a problem in practical use. In Comparative Example 1, the cathode active material layer press process and the solid electrolyte layer single press process were not performed, so that the interface B became rough. Because of this, short-circuit occurred early during charging and discharging.

In Comparative Example 2, since the pressing pressure was low, the interface B became rough, and the relative density of each layer became small. For this reason, a short circuit occurred immediately after fabrication of the test cells. In Comparative Examples 3 and 4, the cathode active material layer press step was not performed, and the interface B became rough. For this reason, short-circuiting occurred early during charging and discharging. In Comparative Example 4, the first intermediate laminate press process was not performed, and the relative density of the positive electrode active material layer was also reduced. In Comparative Example 5, the solid electrolyte layer was not subjected to a single pressing step, so that the relative density of the solid electrolyte layer was reduced. For this reason, a short circuit occurred immediately after fabrication of the test cells. In addition, the thickness of the solid electrolyte layer was also increased. In Comparative Example 6, since the solid electrolyte layer was thicker than Comparative Example 1, the number of cycles to short circuit increased slightly, but short circuit could not be avoided. In Comparative Example 7, since the preliminary pressing step was not performed, not only the interface B was roughened but also the relative density of each layer was reduced. For this reason, a short circuit occurred immediately after fabrication of the test cells.

Reference Example 1 shows that the solid electrolyte layer in Comparative Example 1 is made very thick. The shortening could be suppressed by making the solid electrolyte layer very thick, but the energy density was very small. So, it is not practical. In Reference Example 2, the negative electrode active material in Comparative Example 1 is a graphite system. When the negative electrode active material is made of a graphite system, there is no problem to which the present embodiment is noticed, but the energy density is reduced. Reference Example 3 is a nonaqueous electrolyte secondary battery. Compared with Examples 1 to 7, properties similar to those of Reference Example 3 are obtained in Examples 1 to 7. Thus, Examples 1 to 7 can enjoy the advantages (for example, higher safety, etc.) of all solid secondary batteries while considering the characteristics of batteries similar to non-aqueous electrolyte secondary batteries.

Although the preferred embodiments of the present invention have been described in detail with reference to the accompanying drawings, the present invention is not limited thereto. It will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined in the appended claims. .

1 pre-solid secondary battery
10 anode
11 anode collector
12 cathode active material layer
20 cathode
21 cathode collector
22 anode active material layer
30 solid electrolyte layer

Claims (31)

And a solid electrolyte layer comprising a positive electrode including a positive electrode active material layer, a negative electrode including a negative electrode active material layer, and a solid electrolyte interposed between the positive electrode active material layer and the negative electrode active material layer,
Wherein the arithmetic mean roughness (Ra) at the interface between the positive electrode active material layer and the solid electrolyte layer is 1.0 占 퐉 or less and the relative density of the solid electrolyte layer is 80% or more. The method according to claim 1,
Wherein the anode active material layer comprises lithium. The method according to claim 1,
Wherein the negative active material layer comprises carbon. The method of claim 3,
The carbon may be selected from the group consisting of Ketjen black, carbon black, graphite, carbon nanotubes, carbon fibers, mesoporous carbon, mesocarbon microbeads (MCMB), oil furnace black, but are not limited to, extra-conductive black, acetylene black, lamp black, non-graphitizing carbon, graphitizing carbon, cracked carbon, coke, Characterized in that it comprises glassy carbon or activated carbon. The method according to claim 1,
And the relative density of the cathode active material layer is 60% or more. The method according to claim 1,
Wherein the maximum height illuminance (Rz) at the interface between the cathode active material layer and the solid electrolyte layer is 4.5 占 퐉 or less. The method according to claim 1,
Wherein the cathode active material layer comprises a cathode active material and a solid electrolyte. The method according to claim 1,
Wherein the cathode active material layer comprises a lithium transition metal oxide having a layered rock salt type structure. The method according to claim 1,
Wherein the cathode active material layer comprises a compound represented by LiNi _x Co _y Al _z O ₂ , LiNi _{x '} Co _y' Mn _{z '} O ₂ , or a combination thereof,
0 < y < 1, 0 < z < 1, and 0 < x & x '+ y' + z '= 1. The method according to claim 1,
Wherein the cathode active material layer comprises a compound represented by LiNi _x Co _y Al _z O ₂ , LiNi _{x '} Co _y' Mn _{z '} O ₂ , or a combination thereof,
X <1, 0 <y <1, 0 <z <1, and x + y + z = 1 and 0.7 <x '<1, 0 < x '+ y' + z '= 1. The method according to claim 1,
Wherein the cathode active material layer further comprises a binder. 12. The method of claim 11,
Wherein the binder is selected from the group consisting of vinylidene fluoride / hexafluoropropylene copolymer, polyvinylidene fluoride (PVDF), polyacrylonitrile, polymethylmethacrylate, polytetrafluoroethylene, styrene butadiene rubber polymer, And the second solid-state secondary battery. The method according to claim 1,
Wherein the thickness of the solid electrolyte layer is 100 占 퐉 or less. The method according to claim 1,
The sulfide-based solid electrolyte layer is _{Li 7-a PS 6-a} X a (X is F, Cl, Br, I, or combinations _{thereof, 0≤a <2), aLi 2} S- (1-a) P 2 _{S 5 (0 <a <1} ), aLi 2 S-bP 2 S 5 -cLiX (X is F, Cl, Br, I, or a combination thereof, 0 <a <1, 0 <b <1, 0 <c <1, and a + b + c = 1) , aLi 2 S-bP 2 S 5 -cLi 2 O (0 <a <1, 0 <b <1, 0 <c <1, and a + b _{+ c = 1), aLi 2} S-bP 2 S 5 -cLi 2 O-dLiI (0 <a <1, 0 <b <1, 0 <c <1, 0 <d <1 and a + b + c 0 <a <1, 0 <b <1, 0 <c <1), aLi ₂ S- (1-a) SiS ₂ (0 <a <1), aLi _{2 S} -bSiS ₂ -cLiI , and a + b + c = 1) , aLi 2 S-bSiS 2 -cLiBr (0 <a <1, 0 <b <1, 0 <c <1, and a + b + c = 1) , aLi 2 _{S-bSiS 2 -cLiCl (0 <} a <1, 0 <b <1, 0 <c <1, and a + b + c = 1) , aLi 2 S-bSiS 2 -cB 2 S 3 -dLiI (0 1, 0 <b <1, 0 <c <1, 0 <d <1 and a + b + c + d = 1), aLi ₂ S-bSiS ₂ -cP ₂ S ₅ -dLiI (0 < a <1, 0 <b <1, 0 <c <1, 0 <d <1 and a + b + c + d = 1), aLi ₂ S- (1-a) B ₂ S ₃ (1), aLi ₂ S-bP ₂ S ₅ -cZ _m S _{n wherein} m and n are each independently a positive integer of 1 to 10, Z is Ge, Zn, or Ga, 0 <a < ALi ₂ S- (1-a) GeS ₂ (0 <a <1), aLi ₂ S-bSiS ₂ -cLi ₃ (where 0 <b <1, 0 <c < PO ₄ (0 < a < 1, 0 < b & 1, 0 <c <1, and a + b + c = 1), or aLi ₂ S-bSiS ₂ -cLi _P MO _q where p and q are independently a positive integer of 1 to 10 and 0 <a Wherein M is P, Si, Ge, B, Al, Ga or In), characterized in that it comprises at least one element selected from the group consisting of <1, 0 <b <1, 0 <c <1, and a + b + c = Secondary battery. The method according to claim 1,
Wherein the solid electrolyte layer comprises a solid electrolyte material comprising sulfur (S), phosphorus (P), and lithium (Li). The method according to claim 1,
Wherein the pre-solid secondary battery further comprises a cathode current collector. The method according to claim 1,
Wherein the capacity retention ratio after 50 cycles of the all-solid-state secondary battery is more than 75%. Wherein the pre-solid-state secondary battery has a closed-circuit voltage of more than 2.4V.
A positive electrode comprising a positive electrode active material layer;
1. A negative electrode comprising a negative electrode collector, a negative electrode active material layer on the negative electrode collector, a negative electrode including a negative electrode active material layer between the negative electrode collector and the negative electrode active material layer, the negative electrode active material layer comprising carbon, ; And
A solid electrolyte layer between the cathode active material layer and the anode active material layer;
/ RTI &gt;
Wherein the arithmetic mean roughness (Ra) at the interface between the positive electrode active material layer and the solid electrolyte layer is 1.0 占 퐉 or less and the relative density of the solid electrolyte layer is 80% or more. 20. The method of claim 19,
Wherein the carbon is amorphous. 20. The method of claim 19,
Wherein the plating layer is made of lithium. 20. The method of claim 19,
Wherein the solid electrolyte layer comprises a sulfide solid electrolyte. 19. A method of manufacturing a pre-solid secondary battery according to any one of claims 1 to 18, the method comprising:
Providing a cathode active material layer,
Providing a negative electrode active material layer,
Providing a solid electrolyte layer comprising a sulfide-based solid electrolyte,
Pre-pressing the positive electrode active material layer and the solid electrolyte layer, and
Pressing the electrode laminate including the pre-pressed positive electrode active material layer, the pre-pressed solid electrolyte layer, and the negative electrode active material layer to produce a pre-pressed solid secondary battery;
The step of pre-pressurizing the positive electrode active material layer and the solid electrolyte
Before the pressed positive electrode active material layer is laminated on the solid electrolyte layer, pressing the positive electrode active material layer to provide a pressed positive electrode active material layer; And
And pressing the solid electrolyte layer to provide a pressed solid electrolyte layer before laminating the pressed solid electrolyte layer to the negative electrode active material layer. 24. The method of claim 23,
Wherein the step of pressing the positive electrode active material layer comprises pressing the positive electrode active material layer together with the positive electrode collector. 24. The method of claim 23,
The step of pressing the solid electrolyte layer comprises:
And pressing the solid electrolyte layer alone before lamination of the pressed positive electrode active material layer. 26. The method of claim 25,
The step of pressing the solid electrolyte layer comprises:
Pressing the solid electrolyte layer alone, and
And pressing the first intermediate laminate including the pressed solid electrolyte layer and the pressed positive electrode active material layer. 24. The method of claim 23,
The step of pressing the solid electrolyte layer comprises:
And pressing the second intermediate laminate including the pressed solid electrolyte layer and the pressed positive electrode active material layer. 24. The method of claim 23,
Wherein the anode active material layer is disposed on the anode current collector,
Further comprising filling the entire solid secondary battery to provide a plating layer between the anode active material layer and the anode current collector. 23. A method of manufacturing a pre-solid secondary battery according to any one of claims 19 to 22,
Providing a positive electrode comprising a positive electrode active material layer;
Disposing a solid electrolyte layer on the positive electrode;
Disposing a negative electrode on the solid electrolyte layer, wherein the negative electrode includes a negative electrode current collector and a negative electrode active material layer on the negative electrode current collector, and the negative electrode active material layer includes carbon; And
And providing a voltage between the anode and the cathode to form a plating layer between the anode active material layer and the anode current collector to produce the pre-solid secondary battery. 30. The method of claim 29,
Wherein the carbon is amorphous carbon. &Lt; RTI ID = 0.0 &gt; 11. &lt; / RTI &gt; 29. The method of claim 29,
Wherein the plating layer comprises lithium. &Lt; RTI ID = 0.0 &gt; 11. &lt; / RTI &gt;

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