KR101967975B1 - Slurry composition for Lithium ion secondary battery composite electrodes, manufacturing method of composite electrode using the same and lithium ion secondary battery comprising the same - Google Patents

Abstract

A slurry composition for a lithium secondary battery composite electrode, a method for producing a composite electrode using the same, and a method for manufacturing a lithium secondary battery including the same are provided. In the slurry composition for a composite electrode according to the present invention, a sulfide-based solid electrolyte powder, an electrode active material and a binder are mixed in a solvent, wherein the solvent is a nonpolar solvent and has a hydrogen bonding parameter (δh) of 4 to 7 among Hansen solubility parameters have. According to the present invention, by providing a slurry composition for a composite electrode for electrostatic spray deposition and a method for manufacturing a composite electrode for a lithium secondary battery including the composite slurry composition, it is possible to control the thickness of the composite electrode to be formed and to increase the area thereof, Can be improved.

Description

A slurry composition for a lithium secondary battery composite electrode, a method for manufacturing a composite electrode using the same, and a method for manufacturing a lithium secondary battery comprising the same. {Slurry composition for lithium secondary battery composite electrodes, manufacturing method of composite electrode using same and lithium secondary battery comprising the same}

The present invention relates to a slurry composition for an electrode, and more particularly to a slurry composition for a composite electrode.

With the widespread use of small electronic devices and electric vehicles, the demand for secondary batteries with high energy density is increasing. In recent years, a lithium secondary battery using lithium ion has been widely used as a secondary battery, and researches on it have also been actively conducted.

Since the conventional lithium secondary battery uses a flammable liquid electrolyte, strict packaging is required, and it is difficult to increase the energy density beyond a certain level. Further, the lithium secondary battery using the liquid electrolyte has a very high risk of ignition and explosion due to the problem of using a flammable liquid.

In order to overcome this, studies have been made on an all-solid-state secondary battery in which a combustible liquid electrolyte is replaced by a safer inorganic ceramic material. All solid secondary batteries have high energy density and safety and are attracting attention as a next generation secondary battery.

In order to miniaturize the entire solid lithium secondary battery, a technique of forming a solid electrolyte is important. The solid electrolyte can be manufactured by a thin film process, a thick film process, or the like. In the case of a vapor deposition method which is mainly used in a semiconductor process as a thin film process, the thickness of the electrolyte can be controlled through the thin film, thereby reducing the resistance of the electrolyte. However, it has a disadvantage of maintaining a high degree of vacuum during the manufacturing process. As a result, the unit cost of the process is high and it is difficult to continuously form the thin film.

Most of the solid secondary batteries are manufactured by pressure molding or casting. However, the pressure-molding method is difficult to increase the energy density and it is difficult to form the secondary battery with a large area, and it has a disadvantage that the thickness after manufacture is very thick. The casting method has a merit that a thick film having a relatively large area can be manufactured and the solid electrolyte has a uniform composition distribution. However, the performance of the solid electrolyte is deteriorated compared with the pressure molding method, and it is difficult to control the thickness of the formed thick film. There is a continuing problem of compatibility between the two.

Korean Patent Publication No. 10-2013-0018110

Disclosure of the Invention A problem to be solved by the present invention is to provide a method for producing a composite electrode for a lithium secondary battery and a slurry composition for a composite electrode therefor in order to produce an electrode layer having a desired thickness and a large area, .

According to one aspect of the present invention, there is provided a slurry composition for a lithium secondary battery composite electrode. In the slurry composition for a composite electrode, a sulfide-based solid electrolyte powder, an electrode active material and a binder are mixed in a solvent, and the solvent may be a nonpolar solvent and have a hydrogen bonding parameter (δh) of 4 to 7 in a Hansen solubility parameter.

The solvent may be any one selected from the group consisting of 1,2-dichlorobenzene, 1,2-dichloroethane, and combinations thereof. The binder may have an RED value of 0 to 1 for the solvent. The binder may satisfy the zeta potential value in the slurry to 10 mV to 30 mV. The binder may be any one selected from the group consisting of polystyrene (PS), polyvinyl pyrrolidone (PVP), and combinations thereof.

The sulfide-based solid electrolyte may contain a compound of sulfur and at least two components selected from lithium, phosphorus, boron, silicon and aluminum. The slurry may be a composition for electrostatic spray deposition.

According to another aspect of the present invention, there is provided a method of manufacturing a lithium secondary battery composite electrode. The composite electrode manufacturing method is characterized in that the sulfide-based solid electrolyte powder, the electrode active material and the binder are mixed in a solvent, and the solvent is a nonpolar solvent and has a hydrogen bonding parameter (δh) in the Hansen solubility parameter of 4 to 7 Preparing a slurry composition, and electrostatically spraying the slurry in a contact mode on a current collector in a nitrogen atmosphere to form a composite electrode thick film.

According to another aspect of the present invention, there is provided a method of manufacturing a lithium secondary battery. Wherein the solvent is a non-polar solvent and the hydrogen-binding parameter (δh) in the Hansen solubility parameter is in the range of 4 to 7. The method for producing the lithium secondary battery according to claim 1, wherein the sulfide-based solid electrolyte powder, the first electrode active material and the binder are mixed in a solvent, Depositing a first lithium secondary battery composite electrode thick film by electrostatic spraying the first composite electrode slurry on a current collector, depositing a solid electrolyte slurry containing a powder of a sulfide based solid electrolyte on the first lithium secondary battery composite electrode thick film, And a second electrode active material and a binder are mixed in a solvent on the solid electrolyte thick film, wherein the solvent is a nonpolar solvent, and the solubility parameter of the hydrogen And a coupling parameter (? H) of 4 to 7 is applied to the first composite electrode thick film by electrostatic spraying Than the second lithium secondary batteries comprising the step of depositing a thick film, and a composite electrode, wherein the one of the first electrode active material and the second electrode active material is a cathode active material, and the other may be a negative electrode active material.

The first composite electrode slurry, the solid electrolyte slurry, and the second composite electrode slurry,

Dichlorobenzene, 1,2-dichlorobenzene, 1,2-dichloroethane, and combinations thereof. The first composite electrode slurry, the solid electrolyte slurry, and the second composite electrode slurry may include a binder selected from the group consisting of polystyrene, polyvinyl pyrrolidone, and combinations thereof.

According to the present invention, there is provided a composite electrode slurry composition for electrostatic spray deposition, and a method for manufacturing a composite electrode for a lithium secondary battery using the same, thereby controlling the thickness of the composite electrode and increasing the area thereof, .

The technical effects of the present invention are not limited to those mentioned above, and other technical effects not mentioned can be clearly understood by those skilled in the art from the following description.

1 is a flowchart illustrating a method of manufacturing a composite electrode according to an embodiment of the present invention.
Figure 2 shows the Hansen solubility parameter sphere.
3 illustrates a lithium secondary battery according to an embodiment of the present invention.
4 shows the Hansen solubility parameter sphere of the binder according to Experimental Example 3 of the present invention.
5 is a photograph of the transparency of the slurry according to Experimental Example 3 of the present invention visually observed.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. Rather, the intention is not to limit the invention to the particular forms disclosed, but rather, the invention includes all modifications, equivalents and substitutions that are consistent with the spirit of the invention as defined by the claims.

It will be appreciated that when an element such as a layer, region or substrate is referred to as being present on another element "on," it may be directly on the other element or there may be an intermediate element in between .

Although the terms first, second, etc. may be used to describe various elements, components, regions, layers and / or regions, such elements, components, regions, layers and / And should not be limited by these terms.

FIG. 1 is a flow chart showing a method for producing a composite electrode according to an embodiment of the present invention, and FIG. 2 is a diagram illustrating a Hanse solubility sphere.

Referring to FIG. 1, a slurry for a composite electrode in which a sulfide-based solid electrolyte powder, an electrode active material, a conductive material, and a binder are mixed in a solvent can be prepared (S10). Specifically, the slurry may be a composite electrode slurry for electrostatic spray deposition.

The powder of the sulfide-based solid electrolyte may be an ion conductor containing at least two elements selected from lithium (Li), phosphorus (P), boron (B), silicon (Si) and aluminum (Al) and sulfur. For example, the solid electrolyte powder may be at least one selected from the group consisting of P ₂ S ₅ , P ₂ S ₃ , SiS ₂ , Al ₂ S ₃ , B ₂ S ₃ , Na ₄ SiO ₄ , Na ₂ S, GeS ₂ , NaBO ₂ , NaAlO ₃ , P, B, Si and Al and S in Li ₄ SiO ₄ , Li ₂ S, Li ₃ PO ₄ , Li ₄ SO ₄ , Li ₃ AlO ₃ , LiBO ₂ and LiBF ₄ , Lt; / RTI >

The solid electrolyte powder may be mixed with the solvent at a weight ratio of 1: 5 to 1: 100, specifically 1:10 to 1:20. The weight range may be a range that prevents the clogging, clumping, precipitation, etc. of the compositions in the slurry while preventing nozzle clogging in the electrostatic spraying process.

The electrode active material may be a positive electrode active material or a negative electrode active material. Wherein the cathode active material is at least one selected from the group consisting of LiCoO ₂ , LiMnO ₂ , LiMn ₂ O ₄ , LiNiO ₂ , Li (Ni _a Co _b Mn _c ) O ₂ (0 <a <1, 0 <b < b + c = 1), LiNi 1 - x Co x O 2 (0≤x <1), LiCo 1 - x Mn x O 2 (0≤x <1), LiNi 1 - x Mn x O 2 (0≤ x <1), it may include a LiCoPO ₄ and LiFePO _4, etc. These compounds. The negative electrode active material may include carbon materials such as graphite, carbon fiber, polyacene, vapor grown carbon fiber, coke, mesocarbon microbeads, or metals such as Li, In, Al, Si, .

The conductive material may include carbon. For example, the conductive material may include carbon black such as acetylene black, thermal black, and channel black, graphite, carbon fiber, and the like.

The electrode active material and the conductive material may be in the form of powder like the solid electrolyte, and the powders have a weight ratio of 1: 5 to 1: 100, specifically 1:10 to 1:20, relative to the solvent in the slurry . In addition, the powders may have a particle size which can increase dispersion stability in the slurry and does not cause clogging of the nozzles used in electrostatic spraying. For example, the powders may have a particle size of 1 nm to 3 μm. Such a particle size can be obtained by pulverizing the powders by a ball mill such as a planetary ball mill, a vibrating ball mill, or a horizontal ball mill.

The weight ratio and the particle size of the powders improve the dispersibility of the powder particles in the slurry, and the deposition of the slurry by the electrostatic spray deposition, specifically, the cone-jet mode can be more uniformly performed.

The solvent may be a solvent that can be used for electrostatic spray deposition, for example, nonpolar solvents. Specifically, the solvent may have a low reactivity with the solid electrolyte and the electrode active material.

In order to select the solvent by the reactivity with the solid electrolyte and the conductive material, more objective indicators, specifically Hansen solubility parameters, can be used in this embodiment. At this time, the solubility parameter proposed in the Hansen theory is a function of the dispersion forces (δ _d (dispersion force)), the dipole forces (δ _p (polar) And hydrogen bonding (δ _h (electron exchange)).

For example, the solvent may be those having a value of? _H of 3.6 to 8, specifically, 4 to 7. In this case, the solvent may have a low reactivity with the solid electrolyte and the conductive material, and may have good atomization characteristics, i.e., capable of cone-jet spraying. For example, the solvent can be selected from the group consisting of Heptane, Dodecane, Toluene, Chlorobenzene, 1,2-Dichlorobenzene, 1,2-Dichloroethane (1 , 2-Dichloroethane), or a combination thereof.

The binder increases the binding force of the particles in the slurry to the current collector and / or the bonding force between the slurry particles when the slurry is electrostatically sprayed. Specifically, the binder has a high solubility in the solvent, The degree of dispersion of the slurry, more specifically, the degree of dispersion of the solid electrolyte in the slurry, may be increased.

<Formula 1>

_A ² = 4 R (δ -δ _{d2 d1)} ² + (δ _p1 -δ _p2) ² + (δ _h1 -δ _h2) ²

Solvent: (? _D1 ,? _P1 ,? _H1 )

Binder: (? _D2 ,? _P2 ,? _H2 )

R _o : interaction radius of the polymer

<Formula 2>

RED (Relative energy difference) = R _a / R ₀

For this purpose, the binder may have a RED value of 0 to 1 represented by Equations (1) and (2). At this time, the solvent in which the binder is soluble may be 1,2-dichlorobenzene and 1,2-dichloroethane as described above. For example, the binder may be selected from the group consisting of poly (vinyl butyral), poly (vinyl chloride), poly (vinyl acetate), polystyrene, polymethyl methacrylate And may be any one selected from the group consisting of poly (methyl methacrylate), polyvinylpyrrolidone, and poly (isobutylene).

For example, the zeta potential value in the slurry containing the binder may be at least 10 mV. In this case, good dispersibility of the particles in the slurry, specifically the solid electrolyte, can be obtained.

That is, the binder may have a zeta potential value of, for example, 10 mV to 30 mV among the above RED values of 0 to 1. In other words, the binder may be a binder of the electrostatic spray deposition composite electrode slurry, which can increase the degree of dispersion of the slurry while selecting a solvent having a high solubility. For example, the binder may be, but is not limited to, polystyrene and polyvinylpyrrolidone.

The binder may be contained in an amount of 0.1 wt% to 3 wt% with respect to the solvent. When the lithium secondary battery solid electrolyte thick film is produced by the conventional casting method, the binder contains 10 wt% or more in order to increase physical strength and bonding force of the formed solid electrolyte thick film. However, according to the present invention, the amount of the binder added to the slurry preparation for the electrostatic spraying conditions of the slurry and / or the bonding strength of the solid electrolyte thick film due to the heating of the substrate during spraying can be greatly reduced to a small amount of 3 wt% or less have. As described above, according to the present invention, since the amount of the binder added to the slurry composition is reduced, it is possible to reduce the organic matter acting as a resistance component in the thick solid electrolyte layer and further improve the ionic conductivity of the deposited thick layer sulfide solid electrolyte have.

Referring again to FIG. 1, a composite electrode, specifically a composite electrode thick film, may be deposited by electrostatic spraying the slurry onto the current collector (S20). The current collector may be a metal such as Al, Ti, Cu, Au, Pt, or Ni. (Not shown) for electrostatic spraying may include a syringe containing the slurry, a nozzle through which the slurry is sprayed from the syringe, and a stage on which the current collector is disposed. Between the nozzle and the current collector A predetermined electric field can be formed.

At this time, depending on the distance between the nozzle and the current collector, the size of the electric field applied between the nozzle and the current collector, the flow rate of the slurry ejected from the nozzle, the thickness, uniformity, Surface characteristics and the like can be changed. Specifically, the slurry may be sprayed in a cone-jet mode by the electrostatic atomizing device, and the thick film deposited on the current collector when the slurry is con-jet sprayed has a uniform thickness And can be easily formed into a large area with a desired thickness while being formed.

The slurry can be electrostatically sprayed in an inert gas atmosphere, specifically, a nitrogen (N ₂ ) gas atmosphere. In the nitrogen atmosphere, the contact mode can be formed at an applied voltage of 10 kV to 16 kV, specifically 12 kV to 15 kV, during the electrostatic spraying, so that the lithium secondary battery thick film can be uniformly .

For example, the thickness of the composite electrode thick film may be in the range of 5 탆 to 500 탆.

While the slurry is electrostatically sprayed, the current collector may be heated by a predetermined heat source. The heat source may include a heat ray or a light source (a halogen lamp, a UV lamp, or the like). As the thick film deposited on the current collector is dried by the heat source while the slurry is electrostatically sprayed, the mechanical strength of the thick film and the bonding strength with the current collector are increased and the contactability can be improved. In addition, the subsequent drying step is unnecessary, and the time required for forming the thick film can be shortened.

3 illustrates a lithium secondary battery according to an embodiment of the present invention.

3, the lithium secondary battery according to the present invention is a lithium secondary battery comprising a slurry composition containing the aforementioned sulfide-based solid electrolyte 20, an electrode active material, a conductive material (not shown), a binder 30 and a solvent (not shown) The slurry composition may be a first composite electrode slurry when the electrode active material is the first electrode active material 10 and the formed composite electrode thick film may be a slurry composition in which the first composite electrode slurry is formed by electrostatically spraying the first composite electrode slurry on the current collector, And may be a composite electrode layer 100.

At this time, the solid electrolyte thick film 200 may be further deposited on the first composite electrode layer 100 by a continuous process. The solid electrolyte slurry may be prepared by removing only the electrode active material and the conductive material from the first composite electrode slurry, and the solid electrolyte slurry may be formed on the first composite electrode layer by electrostatic spraying at the time of forming the first composite electrode layer The same or similar deposition conditions can be maintained. On the other hand, on the solid electrolyte thick film, a slurry composition having the same slurry composition as that of the first composite electrode layer, and a second electrode active material 10 'instead of the first electrode active material 10, 300 can be formed.

Either one of the first composite electrode layer 100 and the second composite electrode layer 300 may be a positive electrode layer and the other may be a negative electrode layer.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described herein but may be embodied in other forms.

Preparation Example 1: Preparation of Composite Cathode Slurry Composition for Electrostatic Spray Deposition &gt;

0.525 g of a solid electrolytic powder (70Li ₂ S-27P ₂ S ₅ -3P ₂ O ₅ ), 0.975 g of a LiCoO ₂ powder as a positive electrode active material, and 20.5 g of a carbon black ( super-p) and 0.03 g (2 wt%) of polyvinyl pyrrolidone were mixed to prepare a composite cathode slurry.

&Lt; Preparation Example 2: Preparation of composite anode using electrostatic spray deposition >

The slurry prepared in Preparation Example 1 was electrostatically spray-deposited on Al foil to prepare a composite anode. At this time, the flow rate of the slurry was 5 mL / hr, the deposition distance from the nozzle was 12 cm, and the applied voltage was sprayed in a cone-jet mode in the range of 15 kV to 16 kV in a nitrogen atmosphere. After 30 minutes of deposition, a composite anodic thick film of 48 μm thickness was formed.

< Experimental Example  1: Determination of the reactivity of the solvent in the slurry>

A slurry prepared in the same manner as in Preparation Example 1 was prepared except that the solvent was replaced with heptane, dodecane, toluene, chlorobenzene, 1,2-dichlorobenzene 1,2-Dichlorobenzene, acetone and ethanol. The reactivity with the solid electrolyte and the cathode active material was confirmed in the slurries of the test group, and the Hansen solubility parameters of the solvent were measured.

< Experimental Example  2: Preparation of the solvent in the composite cathode slurry Electric field spray  Characteristics comparison>

The experimental group slurry of Experimental Example 1 described above was electrostatically spray-deposited according to Preparation Example 2 to confirm the electric field spray characteristics. The stability of electrostatic spraying by solvent was judged by whether it was maintained for more than 3 hours in the cone - jet mode, and the range of applied voltage for maintaining the cone - jet mode was measured.

< Experimental Example  3: Comparison of Solubility Characteristics between Solvent and Binder>

The experimental group consisted of poly (vinyl butyral), poly (vinyl chloride), poly (vinyl acetate), polystyrene, polymethyl methacrylate (methyl methacrylate), polyvinylpyrrolidone, poly (vinylidene fluoride), poly (isobutylene), polytetrafluoroethylene, and polyethylene The solubilities of the test group binders in 1,2-dichloroethane were visually observed and the solubilities of the test group binders and the 1,2-dichloroethane solvent were measured as Hansen solubility parameter values .

< Experimental Example  4: Comparison of dispersion in slurry according to binder &gt;

The slurry prepared in the same manner as in Preparation Example 1 was prepared. In the experimental group, the binder was changed to poly (vinyl butyral), poly (vinyl chloride), poly (vinyl chloride) (meth) acrylate), polystyrene, poly (methyl methacrylate), polyvinylpyrrolidone, poly (vinylidene fluoride), polyisobutylene (isobutylene), polytetrafluoroethylene, and polyethylene. The zeta potential values were measured for the dispersion of the slurry of the test group.

The following Tables 1 and 2 show the results according to Experimental Example 1 and Experimental Example 2 of the present invention, respectively. In Table 1 and Table 2, the reactivity between the solvent and the solid electrolyte or the cathode material was quantified to be 0 to 5 (no reactivity was 0, and reactivity was extremely high 5), and in Table 2, Is represented by O, X (smooth: O, not smooth: X).

menstruum Reactivity with solid electrolyte Reactivity with cathode materials Cone-jet mode Heptane 0 0 X Dodecan 0 0 X toluene 0 0 X Chlorobenzene 0 0 X 1,2-Dichlorobenzene One 0 10-15 kV 1,2-dichloroethane One 0 10-15 kV Acetone 4 One 9-10 kV ethanol 5 5 9-10 kV

δ / MPa1 / 2 Reactivity with solid electrolyte Reactivity with cathode materials Electric field spray menstruum _d δ _p δ _h Heptane 15.3 15.3 0 0 0 X Dodecan 16 16 0 0 0 X toluene 18.2 18 1.4 0 0 X Chlorobenzene 19.6 19 3.4 0 0 X 1,2-Dichlorobenzene 20.5 19.2 6.3 One 0 O 1,2-dichloroethane 18 7.4 4.1 One 0 O Acetone 20 15.5 10.4 4 4 O ethanol 26.5 15.8 8.8 5 5 O

As shown in Table 1, acetone and ethanol were found to be inadequate as a solid electrolyte or an anode material. Referring to Table 2, it can be seen that heptane, dodecane, toluene and chlorobenzene have no reactivity with the solid electrolyte or the cathode material, but the electric field spray is not smoothly performed. That is, referring to Tables 1 and 2, it is shown that 1,2-dichlorobenzene and 1,2-dichloroethane can be selected as solvents having low reactivity with a solid electrolyte or a cathode material and excellent electric field spray characteristics .

The following Tables 3 and 4 show the results of Experimental Example 3 and Experimental Example 4 of the present invention, respectively. In Table 3, the Hansen solubility parameter values of each test group binder and the solvent and the values obtained by obtaining the RED values described above in FIGS. 1 and 2 are shown.

δ / MPa1 / 2 bookbinder δd
δ p
δ h
R0
Ra
RED
Polyvinyl butyral 17.4 4.3 8.4 7.4 5.435071 0.734469 Polyvinyl chloride 17.6 7.8 3.4 8.2 1.135782 0.13851 Polyvinyl acetate 20.9 11.3 9.6 13.7 8.893918 0.649184 polystyrene 18.5 4.5 2.9 5.3 3.293934 0.621497 Polymethylmethacrylate 18.1 10.5 7.5 8.6 4.605432 0.535515 Polyvinylpyrrolidone 18 12 8.1 12 6.0959 0.507992 Polyvinylidene fluoride 19.4 15.9 11.3 9.6 11.48608 1.196467 Polyisobutylene 14.5 2.5 4.7 12.7 8.565629 0.674459 Polytetrafluoroethylene 16.2 1.8 3.4 3.9 6.694027 1.716417 Polyethylene 16 0.8 2.8 3.2 7.826238 2.445699

bookbinder Zeta potential (mV) Polyvinyl acetate 17.4 Polyvinyl chloride 17.2 polystyrene 24.2 Polyvinylpyrrolidone 24.8 Polyvinyl butyral 3.55

Referring to Table 3, since 1,2-dichloroethane does not dissolve poly (vinylidene fluoride), polytetrafluoroethylene, and polyethylene as a binder, it is limited in the production of slurry .

Referring to Table 4, among the remaining binders excluding the binder limited by the above-mentioned Table 3, namely, poly (vinylidene fluoride), polytetrafluoroethylene and polyethylene, poly Comparing the zeta potential values of vinyl acetate, polyvinyl chloride, polystyrene, polyvinylpyrrolidone and polyvinylbutyral, polyvinyl butyral proved to be an unsatisfactory binder in the dispersibility of the solid electrolyte in the slurry, In the case of vinyl acetate, polyvinyl chloride, polystyrene and polyvinylpyrrolidone, the zeta potential shows a value of 10 mV or more, which is an excellent binder that improves the dispersibility in the slurry. In particular, polystyrene and polyvinylpyrrolidone The potential value is more than 20mV, which shows better dispersibility. Can.

4 shows the Hansen solubility parameter sphere of the binder according to Experimental Example 2 of the present invention.

Referring to FIG. 4, the solubility of the solvent and the binder can be measured using the Hansen solubility spheres.

5 is a photograph of the transparency of the slurry according to Experimental Example 3 of the present invention visually observed.

Referring to FIG. 5, the solubility of the binder with respect to the solvent in the slurry can be visually confirmed.

It should be noted that the embodiments of the present invention disclosed in the present specification and drawings are only illustrative of specific examples for the purpose of understanding and are not intended to limit the scope of the present invention. It will be apparent to those skilled in the art that other modifications based on the technical idea of the present invention are possible in addition to the embodiments disclosed herein.

10, 10 ': electrode active material 20: solid electrolyte
30: binder 100: first composite electrode layer
200: solid electrolyte membrane 300: second composite electrode layer

Claims (15)

Wherein the solvent is a non-polar solvent and 1,2-dichloroethane having a hydrogen bonding parameter (? H) of 4 to 7 in the solubility parameter of Hansen, and a slurry in which a sulfide- based solid electrolyte powder, an electrode active material and a binder are mixed in a solvent,
Wherein the binder is polyvinylpyrrolidone (PVP) which satisfies RED values for the solvent of 0 to 1 and satisfies a zeta potential value of 20 mV to 30 mV in the slurry. delete delete delete delete The method according to claim 1,
Wherein the sulfide-based solid electrolyte comprises at least two components selected from lithium, phosphorus, boron, silicon and aluminum, and a compound of sulfur. The method according to claim 1,
Wherein the slurry is an electrostatic spray deposition composition. Wherein the solvent is a non-polar solvent and 1,2-dichloroethane having a hydrogen bonding parameter (? H) of 4 to 7 in a solubility parameter of Hansen, and a slurry in which a sulfide-based solid electrolyte powder, an electrode active material and a binder are mixed in a solvent ,
Preparing a slurry composition for a composite electrode, wherein the binder has a RED value of 0 to 1 for the solvent and is polyvinylpyrrolidone (PVP) satisfying a zeta potential value of 20 mV to 30 mV in the slurry; And
And forming a composite electrode thick film by electrostatic spraying the slurry on a current collector in a contact mode in a nitrogen atmosphere. delete delete delete delete Wherein the first solvent is a nonpolar solvent and the hydrogen bond parameter (δh) of the Hansen solubility parameter is 4 (4), wherein the first solvent contains a first sulfide based solid electrolyte powder, a first electrode active material and a first binder mixed in a first solvent. &Lt; / RTI &gt; to 7, 1,2-dichloroethane,
Wherein the first binder is a polyvinylpyrrolidone (PVP) compound having a RED value of 0 to 1 for the first solvent and satisfying a zeta potential value of 20 mV to 30 mV in the first slurry, Depositing a first lithium secondary battery composite electrode thick film by electrostatic spraying the slurry on the current collector;
Depositing a lithium secondary battery solid electrolyte thick film by electrostatic spraying a solid electrolyte slurry containing a powder of a sulfide based solid electrolyte on the first lithium secondary battery composite electrode thick film; And
And a second slurry in which a second sulfide-based solid electrolyte powder, a second electrode active material, and a second binder are mixed in a second solvent on the solid electrolyte thick film, wherein the second solvent is a nonpolar solvent, Dichloroethane with a coupling parameter (? H) of 4 to 7,
Wherein the second binder is a polyvinylpyrrolidone (PVP) compound having a RED value of 0 to 1 for the second solvent and satisfying a zeta potential value of 20 mV to 30 mV in the second slurry, And depositing a second lithium secondary battery composite electrode thick film by electrostatic spraying the slurry onto the first composite electrode thick film,
Wherein one of the first electrode active material and the second electrode active material is a cathode active material and the other is an anode active material. delete delete

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