KR20170050234A - Fabrication method electrode for all-solid-state battery - Google Patents

Abstract

The present invention relates to a fabrication method of an electrode for an all-solid-state battery, and more specifically, to a fabrication method of an electrode for an all-solid-state battery which is capable of increasing an initial discharge capacity of a battery by injecting a polymer electrolyte in fractions after producing a dispersing solution through mixing a carbon fiber conductive material and a dispersing agent in advance, and uniformly dispersing the carbon fiber conductive material and an active material in the polymer electrolyte.

Description

 BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method of manufacturing an electrode for a solid-

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing an electrode for an all solid-state battery in which the charge / discharge capacity of the battery is increased.

Various batteries capable of overcoming the limitations of lithium secondary batteries at present are being studied from the viewpoints of capacity, safety, output, enlargement and miniaturization of batteries.

Typical examples are metal-air batteries with a theoretical capacity in terms of capacity as compared to lithium secondary batteries, all-solid-state batteries with no risk of explosion in terms of safety, and super- (supercapacitor), NaS cell or RFB (redox flow battery) in the aspect of enlargement, and thin film battery in the aspect of miniaturization have been continuously studied in academia and industry.

All solid-state batteries refer to a battery in which a liquid electrolyte used in a lithium secondary battery has been replaced with a solid. Since no flammable solvent is used in the battery, no ignition or explosion occurs due to the decomposition reaction of the conventional electrolyte solution. Can be greatly improved. In addition, since Li metal or Li alloy can be used as a negative electrode material, energy density with respect to the mass and volume of the battery can be remarkably improved.

The production of all solid batteries is performed by a dry compression process in which a solid electrolyte is prepared in a powder state and then charged into a predetermined molding machine or a solid electrolyte is mixed with a solvent and a binder to prepare a slurry, ≪ / RTI >

When the distance between the particles is large, the electron conductivity of the active material is lowered. This problem is solved by using a conductive material and narrowing the distance therebetween. However, securing the electronic conductivity can be ensured only when the active material and the conductive material are dispersed evenly.

As a conductive material, a carbon-based material is used. When a linear conductive material such as carbon fiber is used, the conductive material is not uniformly mixed in the slurry and the conductive materials are agglomerated to form an agglomerate. This aggregate can not participate in the formation of the conduction path of the active material and / or the conductive material, so that not only the electron conductivity is lowered but also the printing property is poor during the production of the electrode, which may deteriorate the battery performance.

Various methods have been proposed for increasing the dispersibility of the conductive material, and the use of dispersants has been widely used.

The dispersant is selected in consideration of the interaction with the active material and the surface of the conductive material and the interfacial characteristics, and Korean Patent Laid-Open Publication No. 2013-0052533 discloses the use of a cellulose-based dispersant such as carboxymethylcellulose or carboxyethylcellulose as a dispersant in a carbonaceous active material And WO No. 2013/038494 discloses a technique of using a deoxyribonucleic acid (DNA) as a dispersant when carbon nanotubes are used as a conductive material.

Although the electrical conductivity of the electrode is improved to some extent through the use of the dispersant, there still remains a problem that the binder, which is essentially used for binding the active material and the dispersant in the slurry composition, acts as a resistance of the electrode.

As a result, a method of using a polymer electrolyte such as PEO instead of a binder has been proposed.

In Japanese Patent Application Laid-Open No. 2008-027662, an electrode slurry is prepared by dispersing a positive electrode active material, a conductive material, and a solid polymer electrolyte in an NMP (N-methyl-2-pyrrolidone) solvent as an anode and sputtering it as an electrode . At this time, polyethylene oxide (PEO), polypropylene oxide (PPO) or the like is used as a solid polymer electrolyte and a lithium salt is used.

The polymer electrolyte consists of a polymer and a lithium salt. Polymers often have polarity in order to dissociate the lithium salt well. Therefore, when an electrode slurry is prepared by dissolving a polymer electrolyte, a polar solvent such as the above-mentioned NMP is generally used. However, the carbon material, which is a conductive material used in the preparation of the electrode slurry, is not well dispersed in a polar solvent, and thus it is difficult to form an electrode slurry and an electrode having a uniform composition.

Particularly, such low dispersibility occurs more seriously when the carbon-based conductive material is a fiber type carbon fiber rather than spherical particles.

The electrode using the polymer electrolyte can be operated smoothly because the active material and the conductive material are uniformly dispersed in the polymer electrolyte so that the ion conduction and the electron conduction network are well formed. Therefore, when a carbon fiber conductive material and a polymer electrolyte are used together with an active material as an electrode material, measures for improving their dispersion state are required.

Korean Patent Publication No. 2013-0052533, "Electrode for Lithium Ion Secondary Battery, Method for Manufacturing the Same, and Lithium Ion Secondary Battery & WO 2013/038494, " ELECTRODE FOR LITHIUM ION SECONDARY BATTERIES, METHOD FOR PRODUCING SAME, AND LITHIUM ION SECONDARY BATTERY " Japanese Patent Application Laid-Open No. 2008-027662, "Secondary Battery"

In order to solve the above problems, the inventors of the present invention conducted a study related to the dispersibility of the electrode slurry composition. As a result, considering the polarity of the solvent capable of effectively dissolving the polymer electrolyte used as the matrix and the polarity of the carbon fiber conductive material, And the initial discharge capacity of the battery can be improved when controlling the dosing time of the polymer electrolyte and controlling the dosing method of the polymer electrolyte so as to form a stable matrix. Thus, the present invention has been completed.

Accordingly, it is an object of the present invention to provide a method of manufacturing an electrode for an all solid-state battery capable of improving the initial discharge capacity of the battery.

In order to accomplish the above object, the present invention provides a method of manufacturing an electrode for a full solid-state battery in which an electrode slurry is coated and then coated on a current collector,

The electrode slurry

(S1) mixing a carbon fiber conductive material and a dispersant in a solvent;

(S2) adding a polymer electrolyte to the obtained dispersion solution; And

(S3) a step of adding an active material and a polymer electrolyte to the electrode assembly.

The electrode for a full solid battery manufactured according to the present invention has a structure in which the active material and the carbon fiber conductive material are uniformly dispersed on the polymer electrolyte to prevent the conventional conductive material from aggregating in the polymer electrolyte, Is dramatically increased.

1 is a schematic view showing a method for producing an electrode slurry according to the present invention.
FIG. 2 is a flow chart showing the manufacture of an electrode for a full-solid battery according to the present invention.
FIG. 3 is a photograph showing the dispersion state of the electrode slurry prepared in (a) Example 1 and (b) Comparative Example 1. FIG.
4 is a scanning electron microscope image of the electrode prepared in (a) Example 1 and (b) Comparative Example 1. Fig.
FIG. 5 is a cross-sectional scanning electron microscope image of the electrode manufactured in (a) Example 1 and (b) Comparative Example 1. FIG.
6 is a graph showing charge and discharge of the battery manufactured in Example 1 and Comparative Example 1. Fig.

The preparation of the electrode for the solid-state battery can be performed by coating the current collector after preparing the electrode slurry, and then drying the electrode slurry. The composition of the electrode slurry affects the battery characteristics.

Electrode slurry composition

The electrode slurry according to the present invention includes a solvent, a carbon fiber conductive material, a dispersant, an active material, and a polymer electrolyte without using a binder, and the final electrode structure is formed by uniformly dispersing a carbon fiber conductive material and an active material in a polymer electrolyte matrix .

As a solvent of the electrode slurry, usually a polar aprotic solvent is used to dissolve the polymer electrolyte. These polar aprotic solvents can not uniformly disperse non-polar fibrous conductive materials, such as carbon fibers, resulting in separation of the carbon fiber conductive material in the electrode slurry or aggregation within the polymer electrolyte matrix.

Therefore, in the present invention, the dispersing agent is selected in consideration of the polarity of the solvent capable of effectively dissolving the polymer electrolyte used as the matrix and the polarity of the conductive material, and the method of administering the polymer electrolyte so as to control the injection timing thereof and to form a stable matrix .

1 is a schematic view showing a method for producing an electrode slurry according to the present invention. Referring to Figure 1, the electrode slurry

(S1) mixing a carbon fiber conductive material and a dispersant in a solvent to prepare a dispersion solution;

(S2) adding a polymer electrolyte to the dispersion solution; And

(S3), followed by adding an active material and a polymer electrolyte.

Each step will be described in more detail below.

First, a dispersion solution is prepared by mixing a carbon fiber conductive material and a dispersant in a solvent (S1).

The dispersion solution disperses the carbon fiber conductive material in the solvent, and the dispersant has a form adsorbed on the surface or the end of the carbon fiber conductive material. The carbon fiber conductive material has a property of easily aggregating with each other. However, when a dispersing solution dispersed only with a carbon fiber conductive material is first prepared by using a dispersant, aggregation thereof does not occur or occurs very little, and a subsequent material ) And the carbon fiber conductive material are improved.

The solvent is used to sufficiently dissolve the polymer electrolyte, to disperse the carbon fiber conductive material, the dispersant, and the subsequent active material. In the present invention, a polar aprotic solvent is used.

A polar aprotic solvent is a solvent in which the hydrogen ion (H ⁺ ) is not bonded around the central element in the formula of the solvent and does not give off the hydrogen ion. This polar aprotic solvent dissolves an ion conductive polymer (for example, a PEO-based polymer) used in the polymer electrolyte of the present invention.

The polar aprotic solvent that can be used is not particularly limited in the present invention, and any known polar aprotic solvent may be used. Typically, the polar aprotic solvent is selected from the group consisting of acetonitrile, tetrahydrofuran, ethyl acetate, acetone, dimethylformamide, dimethylsulfoxide, and combinations thereof, preferably acetonitrile Lt; / RTI >

Such a solvent is used in an amount of 100 to 1500 parts by weight, preferably 150 to 500 parts by weight, per 100 parts by weight of the active material. If the content is less than the above range, the polymer electrolyte will not sufficiently dissolve, or the carbon fiber conductive material, dispersant and / or active material will aggregate together. When the content exceeds the above range, There arises a problem that the porosity of the obtained electrode is increased. Therefore, it is suitably used within the above range.

The carbon fibers used as the conductive material include polyacrylonitrile carbon fibers, rayon carbon fibers, pitch carbon fibers, carbon nanotubes, vapor grown carbon fibers (VGCF), carbon nanofibers (CNFs) Nano Fiber, Activated Carbon Nanofiber (ACNF), Chopped Fiber, and combinations thereof. Preferably, vapor-grown carbon fibers are used.

At this time, the diameter and length of the carbon fiber can be all the range that is usually used as the conductive material of the electrode, and preferably, the diameter is 1 to 1000 nm and the length may be 0.5 to 20 탆. The diameter and the length of the fibrous carbon are related to the improvement of the ion conductivity by better connecting between the active materials. If it is less than the above range, the fabrication is difficult. On the contrary, if the above range is exceeded, fibrous carbon Can occur.

The content of the carbon fiber conductive material is 0.5 to 20 parts by weight, preferably 3 to 10 parts by weight based on 100 parts by weight of the active material. If the content is less than the above range, the effect of improving the ionic conductivity can not be ensured and the output characteristics and capacity of the battery are lowered. On the other hand, if the content exceeds the above range, the effect is not significantly increased, Therefore, it should be adjusted within the above range.

Particularly, in the present invention, when fibrous carbon is used as a conductive material, a dispersant is used to prevent agglomeration between them. 4 (a), the dispersant in the electrode slurry composition is adsorbed on the conductive material to change its surface property to further reduce the cohesive force between the carbon fiber conductive materials, and when the active material is added subsequently, Increase Mars.

Specifically, the dispersing agent is composed of a polymer chain portion having compatibility with a liquid medium (dispersion medium or solvent) and an adsorbing portion having affinity with a carbon fiber conductive material to be dispersed. The dispersant according to the present invention adsorbs on the surface of the conductive material of the carbon fiber and there is a polymer chain part in the solvent therearound to keep the distance between the conductive material of the carbon fibers constant due to the effect of the steric hindrance, Prevent aggregation.

Preferably, the dispersant according to the present invention may be a cationic dispersant, an anionic dispersant, a nonionic dispersant, or an amphoteric dispersant, either individually or in combination.

The dispersant may be a commercial product, for example a specific day, EFKA4008, EFKA4009, EFKA4010, EFKA4015, EFKA4046, EFKA4047, EFKA4060, EFKA4080, EFKA7462, EFKA4020, EFKA4050, EFKA4055, EFKA4400, EFKA4401, EFKA4402, EFKA4403, EFKA4300, EFKA4330, EFKA4340, EFKA6220, EFKA6225, EFKA6700, EFKA6780, EFKA6782, EFKA8503 (EFKA ADDITIVES BV products), TEXAPHOR-UV21, TEXAPHOR-UV61 (Cognis Japan or wrong to manufactured products), DisperBYK101, DisperBYK102, DisperBYK106, DisperBYK108, DisperBYK111, DisperBYK112, DisperBYK116, DisperBYK130 , DisperBYK140, DisperBYK142, DisperBYK145, DisperBYK161, DisperBYK162, DisperBYK163, DisperBYK164, DisperBYK166, DisperBYK167, DisperBYK168, DisperBYK170, DisperBYK171, DisperBYK174, DisperBYK180, DisperBYK182, DisperBYK192, DisperBYK193, DisperBYK2000, DisperBYK2001, DisperBYK2008, DisperBYK2020, DisperBYK2025, DisperBYK2050, DisperBYK2070, DisperBYK2152 BYK320, FTX-220P, FTX-220S, FTX-228P, FTX-710LL, FTX-750LL, BYK377, BYK378, BYK380N, BYK410, BYK425, BYK430 and BYK9132 (produced by Big Chemie Japan K.K.) , Ftergent 212P, printer 220P, printer 222F, printer 228P, printer 245F, printer 245P, printer 250, printer 251, printer 710FM, MEGAFACE F-477, MegaPack 480SF, or MegaPack F-482 (manufactured by Mitsubishi Kagaku Co., Ltd.), 730LM, 730LL, 730LL, Manufactured by DIC Corporation) can be used.

Among them, a cationic dispersant having a basic functional group is preferable, and among them, DisperBYK 161, DisperBYK 163, DisperBYK 2152, DisperBYK 2155, DisperBYK 112, DisperBYK 2008 and BYK 9132 having an amine group are possible.

The content of such a dispersant is used in an amount of 0.1 to 5 parts by weight, preferably 0.5 to 2 parts by weight, based on 100 parts by weight of the active material. The weight ratio of the carbon fiber conductive material to the dispersant is 1: 5 or less. If the content is less than the above range, the carbon fiber conductive material can not be sufficiently dispersed, and the carbon fiber conductive material may form agglomerates. On the other hand, if the content exceeds the above range, Adjust properly within the range.

The preparation of the dispersion solution having the above composition is not limited to the present invention, and a known mixing process may be used.

As an example, the preparation of the dispersion solution in the present invention is carried out in a mixer at 20 to 25 for 1 to 24 hours. If necessary, the dispersion may be performed sequentially or simultaneously with an ultrasonic process in which a frequency in the range of 5 kHz to 50 kHz is applied for 1 minute to 1 hour, or mechanical stirring may be performed with stirring at a speed of 300 rpm to 2000 rpm.

At this time, the mixer may be a device such as a stirring device, a shaking device and a rotary device. Examples of the mixer include a paste mixer, a homogenizer, a ball mill, a bead mill, a planetary mixer, a sand mill, a roll mill, And a method using a dispersing kneading apparatus. A method using a paste mixer is preferable from the viewpoint of suppressing aggregation of the inorganic solid electrolyte.

Next, a polymer electrolyte is added to the dispersion solution prepared in (S1) (S2).

The polymer electrolyte includes an ion conductive polymer and a lithium salt.

Examples of the ion conductive polymer include polyethylene derivatives, polyethylene oxide derivatives, polypropylene oxide derivatives, phosphate ester polymers, agitation lysine, polyester sulfide, polyvinyl alcohol, polyvinylidene, (PEO-MEEGE) branched with a polyethylene oxide derivative MEEGE (2- (2-methoxyethoxy) ethyl glycidyl ether) was used in the examples of the present invention.

The lithium salt is _{LiCl, LiBr, LiI, LiClO 4} , LiBF 4, LiB 10 Cl 10, LiPF 6, LiCF 3 SO 3, LiCF 3 CO 2, LiAsF 6, LiSbF 6, LiAlCl 4, CH 3 SO 3 Li, CF ₃ SO ₃ Li, LiSCN, LiC (CF ₃ SO ₂ ) ₃ , (CF ₃ SO ₂ ) ₂ NLi, (FSO ₂ ) ₂ NLi, chloroborane lithium, lower aliphatic carboxylate lithium, , And preferably LiTFSI (lithium bis (trifluoromethanesulfonyl) imide) represented by (CF ₃ SO ₂ ) ₂ NLi.

At this time, it is preferable that the polymer electrolyte includes 1 to 10 parts by weight of lithium salt per 100 parts by weight of the ion conductive polymer.

Particularly, in the present invention, the polymer electrolyte is divided into two stages and added in portions. That is, the polymer electrolyte becomes a matrix in which the active material and the carbon fiber conductive material are dispersed in the electrode for all the solid batteries. At this time, the polymer electrolyte added in step S2 becomes a medium for dispersion of the carbon fiber conductive material, and the polymer electrolyte added in step S3 becomes a medium for dispersion of the active material, There is an advantage that the carbon fiber conductive material and the active material are uniformly dispersed.

Upon the addition of the divisions, the polymer electrolyte is added in steps (S2) and (S3) in a weight ratio of 0.5: 2 to 2: 0.5, preferably 1: 1. If too little is added in steps (S2) and (S3), it can not sufficiently perform the role as a medium capable of dispersing the carbon fiber conductive material or the active material.

The amount of the polymer electrolyte injected in steps (S2) and (S3) is 5 to 50 parts by weight, preferably 10 to 30 parts by weight, based on 100 parts by weight of the active material. If the content is less than the above range, the effect of improving the ionic conductivity can not be ensured and the output characteristics and capacity of the battery are lowered. On the other hand, if the content exceeds the above range, the effect is not significantly increased, Therefore, it should be adjusted within the above range.

Then, an active material and a polymer electrolyte are added to the mixed solution obtained in the step (S2) to prepare an electrode slurry.

The active material may be a cathode active material when the electrode is a positive electrode or an anode active material when the electrode is a negative electrode.

At this time, each of the electrode active materials can be any active material applied to conventional electrodes, and is not particularly limited in the present invention.

The cathode active material may be varied depending on the use of the lithium secondary battery, and a known material is used for the specific composition. For example, any lithium transition metal oxide selected from the group consisting of lithium cobalt oxide, lithium manganese oxide, lithium copper oxide, lithium nickel oxide and lithium manganese composite oxide, and lithium-nickel-manganese- More specifically, lithium manganese oxides such as Li _{1 + x} Mn _{2 - x} O ₄ (where x is 0 to 0.33), LiMnO ₃ , LiMn ₂ O ₃ and LiMnO ₂ ; Lithium copper oxide (Li ₂ CuO ₂ ); Vanadium oxides such as LiV ₃ O ₈ , LiFe ₃ O ₄ , V ₂ O ₅ and Cu ₂ V ₂ O ₇ ; Lithium nickel oxide represented by LiNi _{1 - x} M _x O ₂ (where M = Co, Mn, Al, Cu, Fe, Mg, B, or Ga and x = 0.01 to 0.3); LiMn _{2 - x} MxO ₂ (where, M = Co, Ni, Fe , Cr, and Zn, or Ta, x = 0.01 to 0.1 Im) or Li ₂ Mn ₃ MO ₈ (where, M = Fe, Co, Ni , Cu or Zn) of lithium manganese complex oxide, Li (Ni _a Co _b Mn _c expressed in), O ₂ (where, 0 <a <1, 0 <b <1, 0 <c <1, a + b + c = 1), Fe ₂ (MoO ₄ ) ₃ ; Sulfur element, disulfide compound, organosulfur compound and carbon-sulfur polymer ((C ₂ S _x ) _n : x = 2.5 to 50, n≥2); Graphite materials; Carbon black based materials such as Super-P, Denka black, acetylene black, Ketjen black, channel black, furnace black, lamp black, summer black and carbon black; Carbon derivatives such as fullerene; Conductive fibers such as carbon fiber and metal fiber; Metal powders such as carbon fluoride, aluminum, and nickel powder; And conductive polymers such as polyaniline, polythiophene, polyacetylene, and polypyrrole; And a form in which a catalyst such as Pt or Ru is supported on the porous carbon support, but the present invention is not limited thereto.

The negative electrode active material may be selected from the group consisting of lithium metal, a lithium alloy, a lithium metal composite oxide, a lithium-containing titanium composite oxide (LTO), and combinations thereof. The lithium alloy may be an alloy of lithium and at least one metal selected from Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Ba, Ra, Al and Sn. The lithium metal composite oxide is any one of metal (Me) oxides (MeO _x ) selected from the group consisting of lithium and Si, Sn, Zn, Mg, Cd, Ce, Ni and Fe. For example, LixFe ₂ O ₃ 0 = x = 1) or LixWO ₂ (0 < x = 1).

In addition to this, the negative electrode active material is SnxMe _{1 - x} Me _'y O _z (Me: Mn, Fe, Pb, Ge; Me': Al, B, P, Si, of the periodic table Group 1, Group 2, Group 3 element, Halogen; 0 < x = 1; 1 = y = 3; 1 = z = 8); _{SnO, SnO 2, PbO, PbO} 2, Pb 2 O 3, Pb 3 O 4, Sb 2 O 3, Sb 2 O 4, Sb 2 O 5, GeO, GeO2 2, Bi 2 O 3, Bi 2 O 4 , and Bi ₂ O ₅ and the like, and carbonaceous anode active materials such as crystalline carbon, amorphous carbon or carbon composite may be used alone or in combination of two or more.

All solids  Battery electrode

The electrode slurry having the above-described composition can be produced as an electrode for a full solid-state battery through a known method.

FIG. 2 is a flow chart showing the manufacture of an electrode for a full-solid battery according to the present invention.

Referring to FIG. 2, the electrode for the entire solid-

(S1) mixing a carbon fiber conductive material and a dispersant in a solvent to prepare a dispersion solution;

(S2) adding a polymer electrolyte to the dispersion solution;

(S3) adding an active material and a polymer electrolyte thereto;

(S4) preparing an electrode slurry composition;

(S5) coating an electrode slurry on a current collector; And

(S6) drying step.

At this time, the steps (S1) to (S3) are performed as described above to prepare an electrode slurry composition (S4).

According to FIG. 3 (a), the electrode slurry thus prepared has a shape in which fine particles are dispersed because no carbon fiber conductive material or agglomerates of the active material are generated at all. The excellent dispersing property is obtained by smoothing the surface of the finally obtained electrode, There is an effect of improving the quality.

(S5), a method of coating the electrode slurry on the current collector includes a method of uniformly dispersing the electrode slurry on the current collector using a doctor blade or the like, a method of die casting, Comma coating, screen printing, and the like. Alternatively, the electrode slurry may be bonded to the current collector by molding on a separate substrate, followed by pressing or lamination.

At this time, the thickness of the coating to be finally coated can be controlled by adjusting the concentration of the slurry solution, the number of times of coating, and the like.

The electrode current collector is a positive electrode current collector when the electrode is a positive electrode, and is a negative electrode current collector when the electrode is a negative electrode.

The positive electrode current collector is not particularly limited as long as it has high conductivity without causing a chemical change in the battery. For example, carbon, nickel , Titanium, silver, or the like may be used.

The negative electrode current collector is not particularly limited as long as it has electrical conductivity without causing chemical change in the battery. For example, carbon, stainless steel, aluminum, nickel, titanium, sintered carbon, , Nickel, titanium, silver or the like, an aluminum-cadmium alloy, or the like can be used. The negative electrode current collector may be formed in various forms such as a film, a sheet, a foil, a net, a porous body, a foam, a nonwoven fabric, and the like having fine irregularities on its surface.

(S6), the electrode slurry coated on the collector is dried to produce a pre-solid battery.

The drying process is a process for removing the solvent and moisture in the slurry to dry the slurry coated on the metal current collector, and may be changed depending on the solvent used. In one example, it is carried out in a vacuum oven at 50-200.

Examples of the drying method include a drying method by hot air, hot air, low-humidity air, vacuum drying, and irradiation with (circle) infrared rays or electron beams. The drying time is not particularly limited, but is usually in the range of 30 seconds to 24 hours.

After the drying process, the process may further include a cooling process, and the cooling process may be a slow cooling process to room temperature so that the recrystallized structure of the binder is well formed.

If necessary, a rolling process may be performed to increase the capacity density of the electrode after the drying process and to increase the adhesion between the current collector and the active materials, thereby compressing the electrode to a desired thickness by passing the electrode between the two heated rolls. The rolling process is not particularly limited in the present invention, and a known rolling process is possible. For example, between rotating rolls or using a flat press machine.

All solids  battery

The electrode manufactured through the above steps can be used as an electrode of an all solid state battery.

The pre-solid battery includes an anode, a cathode, and a solid electrolyte film sandwiched therebetween, wherein the anode, the cathode, or both can be manufactured by the method described above.

According to a preferred embodiment of the present invention, when VGCF (Vapor Grown Carbon Fiber) is used as a conductive material, DisperBYK-2155 is used as a dispersant, PEO-MEEGE / LiTFSI is used as a polymer electrolyte, and LiFePO ₄ is used as an active material. And the carbon fiber conductive material are uniformly dispersed and the aggregation of the carbon fiber conductive material is significantly reduced (see FIG. 5). As a result, as shown in FIG. 6, it can be seen that the initial discharge capacity of the battery is greatly improved.

At this time, the solid electrolyte membrane is not particularly limited in the present invention, and any membrane used for the entire solid battery can be used. For example, it can be formed using an inorganic solid electrolyte or an organic solid electrolyte. The inorganic solid electrolyte may be a ceramic material, and may be crystalline or amorphous. Thio-LISICON (Li _3.25 Ge _0.25 P _0.75 S ₄ ), Li ₂ S-SiS ₂ , LiI-Li ₂ S- _{2, LiI-Li 2 SP 2} S 5, LiI-Li 2 SP 2 O 5, LiI-Li 3 PO 4 -P 2 S 5, Li 2 SP 2 S 5, Li 3 PS 4, Li 7 P 3 S 11 Li ₂ OB ₂ O ₃ , Li ₂ OB ₂ O ₃ -P ₂ O ₅ , Li ₂ OV ₂ O ₅ -SiO ₂ , Li ₂ OB ₂ O ₃ , Li ₃ PO ₄ , Li ₂ O-Li ₂ WO _{4 -B 2 O 3, LiPON, LiBON} , Li 2 O-SiO 2, LiI, Li 3 N, Li 5 La 3 Ta 2 O12, Li 7 La 3 Zr 2 O 12, Li 6 BaLa 2 Ta 2 O 12, Li ₃ PO _{(4-3 / 2w)} Nw (w is w <1), and Li _3.6 Si _0.6 P _0.4 O ₄ .

Examples of the organic solid electrolyte include polymer-based polymers such as polyethylene derivatives, polyethylene oxide derivatives, polypropylene oxide derivatives, phosphate ester polymers, agitation lysine, polyester sulfide, polyvinyl alcohol, and polyvinylidene fluoride May be mixed with a lithium salt. At this time, they may be used alone or in combination of at least one.

The production of the all solid battery having the above-mentioned constitution is not particularly limited in the present invention, and a known method can be used.

For example, a solid electrolyte membrane is disposed between an anode and a cathode, followed by compression molding to assemble the cell.

The assembled cell is installed in a casing and sealed by heat pressing or the like. Laminate packs made of aluminum, stainless steel or the like, and cylindrical or square metal containers are very suitable for the exterior material.

By including the electrode produced by the method of the present invention for producing an electrode slurry composition as a component, it has excellent charge and discharge characteristics. According to Experimental Example 3 of the present invention, it was confirmed that the battery of Example 1 in which the dispersion solution using the dispersing agent was first added and then the polymer electrolyte was added thereto was increased in charge / discharge efficiency of the battery as compared with the conventional method (Comparative Example 1) Respectively.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope and spirit of the invention as disclosed in the accompanying claims. Changes and modifications may fall within the scope of the appended claims.

[Example]

Example  1: electrode slurry composition and All solids  Manufacture of batteries

(Preparation of electrode slurry composition)

In a mixer equipped with a stirrer, 6.38 g of acetonitrile was added, and 0.22 g of VGCF as a conductive material and 0.04 g of DisperBYK-2155 as a dispersant were added and stirred at 1500 rpm for 30 minutes to prepare a dispersion solution. Then, 0.5 g of a polymer electrolyte (0.36 g of PEO-MEEGE, 0.14 g of LiTFSI) was added to the obtained solution, and the mixture was stirred at 1500 rpm for 12 minutes.

3.79 g of LiFePO ₄ and 0.5 g of a polymer electrolyte (0.36 g of PEO-MEEGE, 0.14 g of LiTFSI) were added to the obtained dispersion solution and stirred at 1000 rpm for 12 minutes to prepare an electrode slurry composition.

(Electrode manufacturing)

The prepared electrode slurry composition was coated on the surface of a current collector (aluminum, thickness 15 탆) using a coater and then dried at normal temperature / pressure for 10 hours. Then dried at 80 DEG C for 5 hours, and then rolled at 120 DEG C at a pressure of 30 MPa to prepare an electrode.

(Battery manufacturing)

At this time, the prepared electrode was used as an anode, a lithium electrode was used as a cathode, and a solid electrolyte cell was formed by rolling using Li ₂ OB ₂ O ₃ as a solid electrolyte membrane.

Comparative Example  1: electrode slurry composition and All solids  Manufacture of batteries

Except that the electrode slurry composition was prepared as follows, to prepare an all-solid battery.

The electrode slurry composition was prepared by mixing 6.1 g of methyl ethyl ketone in a mixer equipped with a stirrer, 0.13 g of VGCF as a conductive material, 2.27 g of LiFePO ₄ and 0.5 g of a polymer electrolyte (0.43 g of PEO-MEEGE, 0.17 g of LiTFSI) And the mixture was stirred at 1500 rpm for 54 minutes to prepare an electrode slurry composition.

Experimental Example  1: Evaluation of electrode slurry composition

FIG. 3 is a photograph of the electrode slurry composition prepared in Example 1 and Comparative Example 1, wherein (a) shows the composition of Example 1 and (b) shows the composition of Comparative Example 1. FIG.

3, it can be seen that the electrode slurry composition of Example 1 according to the present invention is uniformly dispersed in the carbon fiber conductive material VGCF, and in the case of the composition of Comparative Example 1 in which the dispersant is not used, VGCF is adsorbed on the vial surface .

4 is a scanning electron micrograph of the electrode slurry composition prepared in Example 1 and Comparative Example 1, wherein (a) shows the slurry composition of Example 1 and (b) shows the slurry composition of Comparative Example 1.

4, it can be seen that in the case of the composition of Example 1, the dispersant is adsorbed (red circle region) on the surface of VGCF.

Experimental Example  2: Evaluation of electrode characteristics

5 is a cross-sectional scanning electron micrograph of the electrode prepared in Example 1 and Comparative Example 1, wherein (a) shows the electrode of Example 1, and (b) shows the electrode of Comparative Example 1. Fig.

Referring to FIG. 5, it can be seen that the active material and the carbon fiber conductive material VGCF are uniformly dispersed in the polymer electrolyte matrix of the electrode of Example 1 according to the present invention. In particular, in the case of the electrode of Comparative Example 1 in which a dispersant was not used, a plurality of carbon fiber conductive materials were observed in a size of 20 to 30 탆, and this phenomenon was not observed in Example 1, have.

Experimental Example  3: Battery performance evaluation

FIG. 6 shows cell characteristics of the electrode prepared in Example 1 and Comparative Example 1, and the results are shown in FIG.

6, it can be seen that the battery having the electrode according to Example 1 according to the present invention has improved charging / discharging capacity compared to the battery of Comparative Example 1 due to the uniform dispersion of the active material and the carbon fiber conductive material.

The method of manufacturing an electrode according to the present invention is applicable to the production of a positive electrode and / or a negative electrode of an all solid state battery.

Claims (11)

A method of manufacturing an electrode for a full-solid battery in which an electrode slurry is coated and then coated on a current collector,
The electrode slurry
(S1) mixing a carbon fiber conductive material and a dispersant in a solvent;
(S2) adding a polymer electrolyte to the obtained dispersion solution; And
(S3) adding an active material and a polyelectrolyte to the electrode. The method according to claim 1,
Wherein the solvent comprises one selected from the group consisting of acetonitrile, tetrahydrofuran, ethyl acetate, acetone, dimethyl formamide, dimethyl sulfoxide, and combinations thereof. The method according to claim 1,
The carbon fiber conductive material may be at least one selected from the group consisting of polyacrylonitrile carbon fibers, rayon carbon fibers, pitch carbon fibers, carbon nanotubes, vapor grown carbon fibers (VGCF), carbon nanofibers (CNF) , Activated carbon nanofiber (ACNF), chopped fiber, and combinations thereof. The method for manufacturing an electrode for an all solid-state battery according to claim 1, The method according to claim 1,
Wherein the dispersant comprises at least one selected from the group consisting of a cationic dispersant, an anionic dispersant, a nonionic dispersant, an amphoteric dispersant, and combinations thereof. The method according to claim 1,
Wherein the polymer electrolyte comprises an ion conductive polymer and a lithium salt. 6. The method of claim 5,
Wherein the ion conductive polymer includes at least one selected from the group consisting of polyethylene derivatives, polyethylene oxide derivatives, polypropylene oxide derivatives, phosphate ester polymers, agitation lysine, polyester sulfide, polyvinyl alcohol, polyvinylidene, A polymer, and a combination thereof. 2. A method for manufacturing an electrode for a full-solid-state cell, comprising the steps of: 6. The method of claim 5,
The lithium salt is _{LiCl, LiBr, LiI, LiClO 4} , LiBF 4, LiB 10 Cl 10, LiPF 6, LiCF 3 SO 3, LiCF 3 CO 2, LiAsF 6, LiSbF 6, LiAlCl 4, CH 3 SO 3 Li, CF ₃ SO ₃ Li, LiSCN, LiC (CF ₃ SO ₂ ) ₃ , (CF ₃ SO ₂ ) ₂ NLi, (FSO ₂ ) ₂ NLi, chloroborane lithium, lower aliphatic carboxylate lithium, And combinations thereof. [Claim 6] The method according to claim 1, The method according to claim 1,
Wherein the polymer electrolyte added in the step (S2) and the step (S3) is added in a weight ratio of 0.5: 2 to 2: 0.5 by weight. The method according to claim 1,
Wherein the active material is a cathode active material or an anode active material for an all solid-state battery. The method according to claim 1,
Wherein the electrode slurry includes 100 to 1500 parts by weight of a solvent, 0.5 to 20 parts by weight of a carbon fiber conductive material, 0.1 to 5 parts by weight of a dispersant, and 5 to 50 parts by weight of a polymer electrolyte, based on 100 parts by weight of the active material. Gt; The method according to claim 1,
Wherein the carbon fiber conductive material: dispersant is used in a weight ratio of 1: 5 or less.

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