KR20130070170A - A separator having porous coating and electrochemical device containing the same - Google Patents

Abstract

PURPOSE: A separator is provided to improve electrical quality and life by using porosity adsorbate and inorganic particle to form porous coating layer on the surface. CONSTITUTION: A separator comprises porous base material(1) having multiple pores, and a porous coating layer formed on the domain more than one kind among the pore of one side of the porous base material and the porous base material. The porous coating layer comprises multiple inorganic particles(2), porosity adsorbate(3), and ' binder fixing inorganic particle and porosity absorbent material. Moreover, electrochemical device comprises cathode, anode, and 'separator interposed between cathode and anode'.

Description

A separator having a porous coating layer and an electrochemical device including the same {A separator having porous coating and electrochemical device containing the same}

The present invention relates to a separator having a porous coating layer and an electrochemical device including the same. More specifically, the porous coating layer is formed on the surface of the separator using a porous adsorbent material and inorganic particles to improve electrical and life characteristics. It relates to a separator and an electrochemical device having the same.

Recently, interest in energy storage technology is increasing. As the application fields of cell phones, camcorders, notebook PCs and even electric vehicles are expanding, efforts for research and development of electrochemical devices are becoming more and more specified. Electrochemical devices have attracted the greatest attention in this respect, among which the development of rechargeable secondary batteries has become a focus of attention. In recent years, in order to improve the capacity density and specific energy in developing such batteries, And research and development on the design of the battery.

Among the currently applied secondary batteries, the lithium secondary battery developed in the early 1990s has advantages such as higher operating voltage and higher energy density than conventional batteries such as Ni-MH, Ni-Cd and sulfuric acid-lead batteries using an aqueous electrolyte solution . However, such a lithium ion battery has safety problems such as ignition and explosion when using an organic electrolytic solution, and it is disadvantageous in that it is difficult to manufacture. Recently, the lithium ion polymer battery has been considered as one of the next generation batteries by improving the weakness of the lithium ion battery, but the capacity of the battery is still relatively lower than that of the lithium ion battery, and the discharge capacity is improved due to insufficient discharge capacity at low temperatures. This is urgently needed.

In addition, the lithium secondary battery has components of a cathode, an anode, a separator, and an electrolyte as power generating elements, and the graphite material is representative of the anode material, and lithium cobalt oxide, lithium iron phosphate, lithium manganese oxide, etc. are mainly used as the cathode material. It is used.

In operation of a lithium battery, some metal components of the cathode material move to the anode surface and oxidize to form metal oxides. The metal oxide on the anode surface thus formed degrades the electrical properties of the anode surface, which negatively affects the cycle characteristics and the life characteristics.

Therefore, it is necessary to reduce the amount of the metal oxide deposited on the anode surface.

The problem to be solved by the present invention is to provide a separator that improves the electrical and life characteristics by forming a porous coating layer on the surface using a porous adsorbent material and inorganic particles.

Another object of the present invention is to provide an electrochemical device having the separator.

According to one aspect of the invention,

A porous substrate having a plurality of pores; And

A porous coating layer formed on at least one surface of the porous substrate and at least one region of pores of the porous substrate, the porous coating layer comprising a plurality of inorganic particles, a porous adsorbent material, and a binder connecting and fixing the inorganic particles and the porous adsorbent material; The separator provided is provided.

The porous adsorbent material may be selected from the group consisting of activated carbon, silica, diatomaceous earth, activated alumina, activated clay, organic / inorganic nanotubes and zeolites.

The pore size of the porous adsorbent material may be 0.001 to 1,000 nm.

The specific surface area of the porous adsorbent material may be 10 to 10,000 m 2 / g.

The average particle diameter of the porous adsorbent material may be 0.01 to 10 ㎛.

An average particle diameter of the inorganic particles may be 0.01 to 10㎛.

The inorganic particles may be selected from the group consisting of inorganic particles having a dielectric constant of 5 or more, inorganic particles having lithium ion transporting ability, and mixtures thereof.

The inorganic particles having a dielectric constant of 5 or more include BaTiO ₃ , Pb (Zr _x , Ti _1-x ) O ₃ (PZT, 0 <x <1), Pb _{1 - x} La _x Zr _{1 -y} Ti _y O ₃ (PLZT hafnia, 0 <x <1, 0 <y <1), (1-x) Pb (Mg 1/3 Nb 2/3) O 3 -xPbTiO 3 (PMN-PT, 0 <x <1), ( HfO ₂ ), SrTiO ₃ , SnO ₂ , CeO ₂ , MgO, NiO, CaO, ZnO, ZrO ₂ , SiO ₂ , Y ₂ O ₃ , Al ₂ O ₃ , SiC and TiO ₂ , or any one thereof Mixtures of two or more of them.

The inorganic particles having a lithium ion transfer ability include lithium phosphate (Li ₃ PO ₄ ), lithium titanium phosphate (Li _x Ti _y (PO ₄ ) ₃ , 0 <x <2, 0 <y <3), and lithium aluminum titanium phosphate (Li _x Al _y Ti _z (PO ₄ ) ₃ , 0 <x <2, 0 <y <1, 0 <z <3), (LiAlTiP) _x O _y series glass (0 <x <4, 0 <y <13), lithium lanthanum titanate (Li _x La _y TiO ₃ , 0 <x <2, 0 <y <3), lithium germanium thiophosphate (Li _x Ge _y P _z S _w , 0 <x <4 , 0 <y <1, 0 <z <1, 0 <w <5), lithium nitride (Li _x N _y , 0 <x <4, 0 <y <2), SiS ₂ (Li _x Si _y S _z , 0 <x <3, 0 <y <2, 0 <z <4) series glass and P ₂ S ₅ (Li _x P _y S _z , 0 <x <3, 0 <y <3, 0 <z <7) It may be any one selected from the group consisting of series glass or a mixture of two or more thereof.

The binder is polyvinylidene fluoride-co-hexafluoropropylene, polyvinylidene fluoride-co-trichloroethylene, polymethylmethacrylate, polymethylmethacrylate, poly Butyl acrylate (polybutylacrylate), polyacrylonitrile, polyvinylpyrrolidone, polyvinylacetate, ethylene vinyl acetate copolymer (polyethylene-co-vinyl acetate), polyethylene oxide ), Polyarylate, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, cyanoethylpullulan, cyanoethylpoly Vinyl alcohol (cyanoethylpolyvinylalcohol), Cyanoethylcellulose, cyanoethylsucrose, pullulan, and carboxyl methyl cellulose, or any one or a mixture of two or more thereof.

The content of the porous adsorbent material may be 5 to 95 parts by weight based on 100 parts by weight of the total of the inorganic particles and the binder polymer.

The weight ratio of the inorganic particles and the binder may be 50:50 to 99: 1.

The porous substrate may be a polyolefin-based porous membrane or nonwoven fabric.

The porous substrate is a high density polyethylene, low density polyethylene, linear low density polyethylene, ultra high molecular weight polyethylene, polypropylene polyethylene terephthalate (polyethyleneterephthalate), polybutylene terephthalate (polybutyleneterephthalate), polyester (polyester), polyacetal (polyacetal), polyamide (polyamide), polycarbonate, polyimide, polyetheretherketone, polyethersulfone, polyphenyleneoxide, polyphenylenesulfidro and polyethylenenaphthalene It may be formed of any one selected from the group consisting of (polyethylenenaphthalene) or a mixture of two or more thereof.

According to another aspect of the present invention,

There is provided an electrochemical device comprising a cathode, an anode, and a separator interposed between the cathode and the anode, wherein the separator is the separator described above.

The electrochemical device may be a lithium secondary battery.

When a separator having a porous coating layer containing a porous adsorption material and inorganic particles is used in an electrochemical device, the metal component from the cathode is trapped by the porous adsorption material in the porous coating layer of the separator so that the metal component at the anode or the anode surface. This precipitation is suppressed. Therefore, the efficiency of the anode is prevented from being lowered, thereby improving the electrical characteristics and life characteristics of the electrochemical device.

1 is a schematic diagram illustrating a separator according to an embodiment of the present invention.
2 is a schematic diagram showing a state where a conventional separator is in contact with an anode.
3 is a schematic diagram illustrating a state in which a separator contacts an anode according to an embodiment of the present invention.

Hereinafter, the present invention will be described in detail with reference to the drawings. The terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary terms and the inventor may appropriately define the concept of the term in order to best describe its invention It should be construed as meaning and concept consistent with the technical idea of the present invention.

According to an aspect of the present invention,

A porous substrate having a plurality of pores; And

A porous coating layer formed on at least one surface of the porous substrate and at least one region of pores of the porous substrate, the porous coating layer comprising a plurality of inorganic particles, a porous adsorbent material, and a binder connecting and fixing the inorganic particles and the porous adsorbent material; Equipped.

When the porous coating layer including the porous adsorbent material and the inorganic particles is formed on at least one surface of the separator, the metal component generated at the cathode does not precipitate as a result of the oxidation reaction on the anode surface, and porous adsorption is performed while passing through the porous coating layer. Adsorbed into the fine pores of the material. Therefore, the precipitation of metal oxides on the surface of the anode is suppressed, thereby improving the electrical and life characteristics of the electrochemical device.

The inorganic particles applied to the porous coating layer may be used having an average particle diameter of 0.01 to 10㎛. These inorganic particles are not particularly limited as long as they are electrochemically stable. That is, the inorganic particles are not particularly limited as long as the inorganic particles are not oxidized and / or reduced in the operating voltage range (for example, 0 to 5 V on the basis of Li / Li ⁺ ). In particular, in the case of using the inorganic particles having the ion transport ability, it is possible to improve the performance by increasing the ion conductivity in the electrochemical device.

Further, when inorganic particles having a high dielectric constant are used as the inorganic particles, dissociation of an electrolyte salt, for example, a lithium salt in the liquid electrolyte, can also contribute to enhance the ionic conductivity of the electrolyte.

For the foregoing reasons, the inorganic particles may include high dielectric constant inorganic particles having a dielectric constant of 5 or more, or 10 or more, inorganic particles having a lithium ion transfer ability, or a mixture thereof.

Non-limiting examples of the inorganic particles having a dielectric constant of 5 or more include BaTiO ₃ , Pb (Zr _x Ti _1-x ) O ₃ (PZT, where 0 <x <1) and Pb _1-x La _x Zr _1-y Ti _y O ₃ (PLZT, where, 0 <x <1, 0 <y <1 Im), (1-x) Pb (Mg 1/3 Nb 2/3) O 3 -xPbTiO 3 (PMN-PT, where 0 <x <1), hafnia (HfO ₂ ), SrTiO ₃ , SnO ₂ , CeO ₂ , MgO, NiO, CaO, ZnO, ZrO ₂ , Y ₂ O ₃ , Al ₂ O ₃ , SiC, TiO _2, etc. It can be used individually or in mixture of 2 or more types.

In particular, BaTiO ₃ , Pb (Zr _x Ti _1-x ) O ₃ (PZT, where 0 <x <1), Pb _1-x La _x Zr _1-y Ti _y O ₃ (PLZT, where 0 < x <1, 0 <y < 1 Im), (1-x) Pb (Mg 1/3 Nb 2/3) O 3 -xPbTiO 3 (PMN-PT, where 0 <x <1), hafnia (HfO Inorganic particles such as ₂ ) not only exhibit high dielectric constant characteristics of dielectric constant above 100, but also have piezoelectricity in which electric charges are generated when a tension or tension is applied under a constant pressure, thereby causing a potential difference between both surfaces. The internal short circuit of the positive electrode can be prevented from occurring, and the safety of the electrochemical device can be improved. Further, when the above-mentioned high-permittivity inorganic particles and inorganic particles having lithium ion transferring ability are mixed, their synergistic effect can be doubled.

The inorganic particles having the lithium ion transferring ability refer to inorganic particles that contain a lithium element but do not store lithium but have a function of transferring lithium ions. The inorganic particles having lithium ion transferring ability exist in the particle structure Since lithium ions can be transferred and transferred due to a kind of defect, the lithium ion conductivity in the battery can be improved and the battery performance can be improved. Examples of the inorganic particles having lithium ion transferring ability include lithium phosphate (Li ₃ PO ₄ ), lithium titanium phosphate (Li _x Ti _y (PO ₄ ) ₃ , 0 <x <2, 0 <y < (Li _x Al _y Ti _z (PO ₄ ) ₃ , 0 <x <2, 0 <y <1, 0 <z <3), 14Li ₂ O-9Al ₂ O ₃ -38TiO ₂ -39P ₂ O ₅ Such as (LiAlTiP) _x O _y series glass (0 <x <4, 0 <y <13), lithium lanthanum titanate (Li _x La _y TiO ₃ , 0 <x <2, 0 <y <3), Li Lithium germanium thiophosphate such as _3.25 Ge _0.25 P _0.75 S _4, etc. (Li _x Ge _y P _z S _w , 0 <x <4, 0 <y <1, 0 <z <1, 0 <w <5), Lithium nitride, such as Li ₃ N (Li _x N _y , 0 <x <4, 0 <y <2), Li ₃ PO ₄ -Li ₂ S-SiS ₂ SiS ₂ based glass, such as _{(Li x Si y S z,} 0 <x <3, 0 <y <2, 0 <z <4), LiI-Li 2 SP 2 S 5 There is P ₂ S ₅ based glass _{(Li x P y S z,} 0 <x <3, 0 <y <3, 0 <z <7) or a mixture thereof as such.

The porous adsorbent material constituting the porous coating layer together with the inorganic particles has a property of adsorbing metals or other impurities generated during operation of the battery by having micropores, and mixed with the inorganic particles to form a porous coating layer. Any material that can be used can be used without limitation. Non-limiting examples of such porous adsorbent materials include activated carbon, silica, diatomaceous earth, activated alumina, activated clay, organic / inorganic nanotubes and zeolites. In this case, the organic / inorganic nanotubes may be used without limitation as long as they have a length of 1 μm or less and have adsorption characteristics for metals or gases. Specifically, the organic / inorganic nanotubes include carbon nanotubes, imogolite, but are not limited thereto.

The pore size of the porous adsorption material may be determined by the specific size of the material to be adsorbed, and is usually formed in micro units or less, for example, may be 0.001 to 1,000 nm, or 0.01 to 100 nm. When the pore size of the porous adsorbent material satisfies this range, it is released from the cathode and introduced to the anode, and metals are deposited on the anode surface by capturing impurities such as metals of 0.001 to 1,000 nm size before reaching the anode surface. Can be prevented in advance.

In addition, the specific surface area of the porous adsorbent material may be an indicator of the capacity of the adsorbable metal impurities, for example, 10 to 10,000 m 2 / g, or 100 to 1,000 m 2 / g. When the specific surface area satisfies such a range, while preserving the stability improving function of the existing inorganic particle layer, by adsorbing sufficiently before the metal particles are precipitated toward the anode, it is possible to prevent performance degradation such as a decrease in capacity of the battery.

In addition, the average particle diameter of the porous adsorbent material may be 0.01 to 10 ㎛, or 0.1 to 1 ㎛. When the average particle diameter satisfies this range, the porous coating layer is formed together with the inorganic particles, the pore characteristics of the porous coating layer and the stability of the separator can be maintained, and the metal introduced from the cathode side stays in the porous coating layer which is sufficiently dense and porous. It is trapped by the adsorbent material and can prevent precipitation on the anode side surface, thereby improving battery performance.

As described above, the porous adsorbent material and the inorganic particles form a porous coating layer on at least one surface of the separator, and a binder is used to bind them to the separator.

In the separator according to one aspect of the present invention, the binder used for forming the porous coating layer may be a polymer commonly used in the art for forming a porous coating layer. In particular, a polymer having a glass transition temperature (T _g ) of −200 to 200 ° C. may be used because it may improve mechanical properties such as flexibility and elasticity of the finally formed porous coating layer. Such a binder faithfully plays a role of a binder for stably connecting and stably separating inorganic particles, thereby contributing to preventing mechanical property degradation of the separator into which the porous coating layer is introduced.

In addition, the binder does not necessarily have an ion conducting ability, but when a polymer having an ion conducting ability is used, the performance of the electrochemical device may be further improved. Therefore, the binder may use one with the highest possible dielectric constant. In fact, since the degree of dissociation of the salt in the electrolyte depends on the permittivity constant of the electrolyte solvent, the higher the dielectric constant of the polymer, the higher the dissociation of salt in the electrolyte. The dielectric constant of such a binder can be in the range of 1.0 to 100 (measuring frequency = 1 kHz), in particular 10 or more.

In addition to the functions described above, the binder may have a feature that can exhibit a high degree of swelling of the electrolyte by gelling upon impregnation of the liquid electrolyte. Accordingly, the solubility index of the binder is in the range of 15 to 45 MPa ^1/2 or 15 to 25 MPa ^1/2 and 30 to 45 MPa ^1/2 . Therefore, hydrophilic polymers having many polar groups can be used more than hydrophobic polymers such as polyolefins. If the solubility index is less than 15 MPa &lt; ^1/2 &gt; and more than 45 MPa &lt; ^1/2 &gt;, it may be difficult to swell by a common battery liquid electrolyte.

Non-limiting examples of such binders include polyvinylidene fluoride-co-hexafluoropropylene, polyvinylidene fluoride-co-trichloroethylene, polymethylmethacrylate. (polymethylmethacrylate), polybutylacrylate, polyacrylonitrile, polyvinylpyrrolidone, polyvinylacetate, ethylene vinyl acetate copolymer (polyethylene-co-vinyl acetate), Polyethylene oxide, polyarylate, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, cyanoethylpullulan Cyanoethyl Polyvinyl Alcohol cyanoethylpolyvinylalcohol, cyanoethylcellulose, cyanoethylsucrose, pullulan, and carboxyl methyl cellulose.

The weight ratio of the inorganic particles to the binder may be 50:50 to 99: 1, or 60:40 to 90:10, or 70:30 to 80:20.

The content of the porous adsorbent material may be, for example, 5 to 95 parts by weight and 10 to 90 parts by weight based on 100 parts by weight of the total of the inorganic particles and the binder polymer.

When the content of the porous adsorption material satisfies this range, the adsorption effect may be sufficiently expressed to improve battery performance, and safety improvement of the separator by the porous coating layer may be ensured.

In addition, the thickness of the porous coating layer composed of the porous adsorbent material, the inorganic particles, and the binder is not particularly limited, but may be in the range of 0.01 to 20 μm. Also, the pore size and porosity of the porous coating layer are not particularly limited, but the pore size may be in the range of 0.01 to 10 μm, and the porosity may be in the range of 5 to 90%.

In addition, in the separator of the present invention, any porous substrate commonly used for an electrochemical device may be used as the porous substrate on which the porous coating layer is formed. For example, a polyolefin-based porous membrane or a nonwoven fabric may be used. However, the present invention is not particularly limited thereto.

Examples of the polyolefin-based porous film include polyolefin-based polymers such as polyethylene, polypropylene, polybutylene, and polypentene, such as high density polyethylene, linear low density polyethylene, low density polyethylene and ultra high molecular weight polyethylene, One membrane can be mentioned.

The nonwoven fabric may be, for example, polyethylene terephthalate, polybutyleneterephthalate, polyester, polyacetal, polyamide, polycarbonate, or polycarbonate. ), Polyimide, polyetheretherketone, polyethersulfone, polyphenyleneoxide, polyphenylenesulfidro, polyethylenenaphthalene, etc. Or the nonwoven fabric formed from the polymer which mixed these is mentioned. The structure of the nonwoven fabric may be a spun bond nonwoven fabric or a meltblown nonwoven fabric composed of long fibers.

The thickness of the porous substrate is not particularly limited, but may be 5 to 50 μm, and the pore size and pore present in the porous substrate are also not particularly limited, but may be 0.01 to 50 μm and 10 to 95%, respectively.

In the porous coating layer, the binder is attached to each other (ie, the binder is connected and fixed between the inorganic particles and the porous adsorbent material) so that the inorganic particles and the porous adsorbent materials are bound to each other, and the porous coating layer is a binder. By maintaining the state bound to the porous substrate. The inorganic particles and the porous adsorbent materials of the porous coating layer are present in the closest packed structure in substantially contact with each other, and the interstitial volume generated when the inorganic particles and the porous adsorbent materials are in contact with each other causes pores of the porous coating layer. do.

The separator according to an aspect of the present invention may further include other additives in addition to the above-described inorganic particles, porous adsorbents and binders as the porous coating layer component.

The additive is not particularly limited as long as it is a substance required or additionally required for the operation or performance improvement of the electrochemical device and is continuously consumed due to consumption in the operation process.

Non-limiting examples of such an electrochemical device performance improvement additive may include any one or a mixture of two or more thereof, such as an additive for forming a solid electrolyte interface, an additive for inhibiting battery side reaction, an additive for improving thermal stability, an additive for inhibiting overcharge, and the like. .

The additive for forming the solid electrolyte interface may be any one selected from the group consisting of vinylene carbonate, vinylethylene carbonate, fluoroethylene carbonate, cyclic sulfite, saturated sultone, unsaturated sultone, acyclic sulfone, and derivatives thereof. Mixtures of two or more of them may be used, but are not limited thereto.

The cyclic sulfites include ethylene sulfite, methyl ethylene sulfite, ethyl ethylene sulfite, 4,5-dimethyl ethylene sulfite, 4,5-diethyl ethylene sulfite, propylene sulfite, 4,5-dimethyl propylene sulfide Pite, 4,5-diethyl propylene sulfite, 4,6-dimethyl propylene sulfite, 4,6-diethyl propylene sulfite, 1,3-butylene glycol sulfite, and the like. 1,3-propane sultone, 1,4-butane sultone, and the like, and unsaturated sultone include ethene sultone, 1,3-propene sultone, 1,4-butene sultone, 1-methyl-1,3-prop Pen sulfone etc. are mentioned, As acyclic sulfone, divinyl sulfone, dimethyl sulfone, diethyl sulfone, methyl ethyl sulfone, methyl vinyl sulfone, etc. are mentioned.

The battery side reaction inhibitory additives include ethylenediaminetetraacetic acid, tetramethylethylenediamine, pyridine, dipyridyl, ethylbis (diphenylphosphine), butyronitrile, succinonitrile, iodine, ammonium halide, and One or a mixture of two or more thereof selected from the group consisting of derivatives thereof may be used, but is not limited thereto.

Examples of the thermostability-improving additive include one or two or more selected from the group consisting of hexamethyldisiloxane, hexamethoxycyclotriphosphazene, hexamethylphosphoramide, cyclohexylbenzene, biphenyl, dimethylpyrrole, and derivatives thereof But are not limited thereto.

The overcharge inhibiting additive may be one or a mixture of two or more selected from the group consisting of n-butyl ferrocene, a halogen substituted benzene derivative, cyclohexylbenzene, and biphenyl, but is not limited thereto.

As an example of the electrochemical device performance improving additive, derivatives of the compounds include compounds in which at least one of hydrogen atoms bonded to carbon atoms of each compound is substituted with halogen.

The content of the electrochemical device performance improving additive may be 2 to 20 parts by weight, 4 to 18 parts by weight, or 6 to 15 parts by weight based on 100 parts by weight of the total amount of the inorganic particles and the binder.

When the content of the additive satisfies the above range, the effect of the addition is sufficiently exhibited, the excessive additive is released to prevent the side reaction, and the cycle of the battery can be prevented from being degenerated early.

1 is a schematic diagram illustrating a separator according to an embodiment of the present invention.

Referring to FIG. 1, a separator according to an aspect of the present invention may include a porous coating layer including inorganic particles 2, a porous adsorption material 3, and a binder (not shown) on one or both surfaces of a porous substrate 1. Can be. An additive as described above may further exist in the empty space between the inorganic particles 2.

When the polyolefin-based porous membrane is used as the porous substrate 1, a porous coating layer made of inorganic particles, a porous adsorption material and a binder may be formed. And a porous coating layer formed of a binder may be formed by being impregnated in the pores of the porous substrate, or formed on both surfaces or one surface of the porous substrate.

At this time, the polyolefin-based nonwoven fabric used as the porous substrate may have a pore size of 500 nm to 10 탆 which is much larger than that of the polyolefin-based porous film having pores of about 100 nm or less.

2 is a schematic diagram showing a state where a conventional separator 1 is in contact with the anode 4. Referring to FIG. 2, the metal component 5 generated at the cathode is oxidized in the vacant space between the surface of the anode 4 or between the anode and the adjacent inorganic particles 2 to precipitate as an oxide.

On the other hand, Figure 3 is a schematic diagram showing a state in which the separator in contact with the anode according to an embodiment of the present invention. Referring to FIG. 3, the separator 1 having the porous coating layer as described above may be disposed such that the porous coating layer contacts the anode 4. In such a structure, the metal component 5 generated at the cathode is adsorbed into the pores of the porous adsorbent material 3, whereby an oxidation reaction occurs at the surface of the anode 4 to cause the metal in the void space between the inorganic particles 2 to be formed. The phenomenon in which the component 5 precipitates can be prevented.

The method of manufacturing the separator according to one aspect of the present invention is illustrated below, but the present invention is not limited thereto.

The above-mentioned binder is dissolved in a solvent to prepare a binder solution. As the solvent, a solubility index similar to that of a binder to be used may be used, and a solvent having a low boiling point may be used. This is because the mixing can be made uniform and then the solvent can be easily removed. Non-limiting examples of the solvent include acetone, tetrahydrofuran, methylene chloride, chloroform, dimethylformamide, N-methyl-2-pyrrolidone (N- methyl-2-pyrrolidone (NMP), cyclohexane, water or a mixture thereof.

Subsequently, inorganic particles, porous adsorbents and optionally other additives are added to the prepared binder solution to prepare a coating liquid in which inorganic particles, porous adsorbents and the like are dispersed.

In this case, after the inorganic particles and the porous adsorbent are added to the binder solution, the inorganic particles and the porous adsorbent may be crushed. The crushing time is suitably 1 to 20 hours, and the particle diameters of the crushed inorganic particles and the porous adsorbent material may be 0.01 to 10 μm and 0.01 to 10 μm, respectively, as mentioned above. As the shredding method, a conventional method may be used, and in particular, a ball mill method may be used.

On the other hand, since the uniform dispersion of the porous adsorbent material between the inorganic particles may increase the efficiency of adsorbing impurities such as metals later, their uniform dispersion in the binder solution is important. When coated with a coupling agent so as to be well dispersed in such a binder solution, the coating solution may be prepared by simply mixing the inorganic particles and the porous adsorbent material in the binder solution.

Then, a coating liquid in which inorganic particles, porous adsorbent material and other additives are dispersed is applied to at least one surface of the porous substrate to form a porous coating layer.

The coating liquid may be coated on the porous substrate using a conventional coating method known in the art, for example, a dip coating, a die coating, a roll coating, a comma coating Or a mixture method thereof may be used. Further, the porous coating layer can be selectively formed on both or only one side of the porous substrate.

When a solvent is added to the coating liquid, it is needless to say that a drying process of the coating layer is further required. Drying conditions are possible in a batch or continuous manner using an oven or a heated chamber in a temperature range that takes into account the vapor pressure of the solvent used.

The separator according to one aspect of the present invention thus manufactured can be usefully used as a separator of an electrochemical device, that is, as a separator interposed between a cathode and an anode.

An electrochemical device according to one aspect of the present invention includes all devices that perform an electrochemical reaction, and specific examples thereof include capacitors such as all kinds of primary, secondary, fuel cell, solar cell, or super capacitor devices. ). In particular, a lithium secondary battery including a lithium metal secondary battery, a lithium ion secondary battery, a lithium polymer secondary battery, or a lithium ion polymer secondary battery may be included in the secondary battery.

The electrode to be applied together with the separator according to one aspect of the present invention is not particularly limited, and the electrode active material may be bound to an electrode current collector according to a conventional method known in the art. Examples of the cathode active material include, but are not limited to, lithium manganese oxide, lithium cobalt oxide, lithium nickel oxide, lithium iron oxide, or a combination thereof A lithium complex oxide may be used. As a non-limiting example of the anode active material, a conventional anode active material that can be used for an anode of an electrochemical device can be used. In particular, lithium metal or a lithium alloy, carbon, petroleum coke, activated carbon, Lithium adsorbing materials such as graphite or other carbon-based materials and the like can be used. Non-limiting examples of the cathode current collector include aluminum, nickel, or a combination thereof, and examples of the anode current collector include copper, gold, nickel, or a copper alloy or a combination thereof Foil to be manufactured, and the like.

Electrolyte that may be used in the electrochemical device in accordance with one aspect of the present invention is A ⁺ B ^- A salt of the structure, such as, A ⁺ is Li ^+, Na ^+, an alkali metal cation or an ion composed of a combination thereof, such as K ⁺ It includes and B a ^- is _{^{PF 6 -, BF 4 -,}} Cl -, Br -, I -, ClO 4 -, AsF 6 -, CH 3 CO 2 -, CF 3 SO 3 -, N (CF 3 SO 2) _{^{2 -, C (CF 2 SO}} 2) 3 - anion, or a salt containing an ion composed of a combination of propylene carbonate (PC) such as, ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC ), Dipropyl carbonate (DPC), dimethyl sulfoxide, acetonitrile, dimethoxyethane, diethoxyethane, tetrahydrofuran, N-methyl-2-pyrrolidone (NMP), ethylmethyl carbonate (EMC), gamma buty Dissolved or dissociated in an organic solvent consisting of rolactone (g-butyrolactone) or mixtures thereof, but not limited thereto It is not.

The electrolyte injection may be performed at an appropriate stage of the battery manufacturing process, depending on the manufacturing process and required properties of the final product. That is, it can be applied before assembling the cell or at the final stage of assembling the cell.

As a process for applying the separator according to one aspect of the present invention to a battery, a lamination, stacking and folding process of a separator and an electrode can be performed in addition to a general winding process.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to examples. However, the embodiments according to the present invention can be modified into various other forms, and the scope of the present invention should not be construed as being limited to the embodiments described below. The embodiments of the present invention are provided to enable those skilled in the art to more fully understand the present invention.

1: porous substrate, 2: inorganic particles, 3: porous adsorbent material
4: anode, 5: metal component

Claims (19)

A porous substrate having a plurality of pores; And
A porous coating layer formed on at least one surface of the porous substrate and at least one region of pores of the porous substrate, the porous coating layer including a plurality of inorganic particles, a porous absorbent material, and a binder connecting and fixing the inorganic particles to the porous absorbent material; Separator to be equipped. The method of claim 1,
The porous adsorbent is selected from the group consisting of activated carbon, silica, diatomaceous earth, activated alumina, activated clay, organic / inorganic nanotubes and zeolites. The method of claim 1,
The pore size of the porous adsorbent material is 0.01 nm to 1,000 nm. The method of claim 1,
Separators having a specific surface area of the porous adsorbent material is 10 to 10,000 m 2 / g. The method of claim 1,
Separators having an average particle diameter of the porous adsorbent material is 0.01 to 10 ㎛. The method of claim 1,
Separators having an average particle diameter of the inorganic particles is 0.01 to 10㎛. The method of claim 1,
The inorganic particles are selected from the group consisting of inorganic particles having a dielectric constant of 5 or more, inorganic particles having a lithium ion transfer ability, and mixtures thereof. The method of claim 7, wherein
The inorganic particles having a dielectric constant of 5 or more are BaTiO ₃ , Pb (Zr _x , Ti _1-x ) O ₃ (PZT, 0 <x <1), Pb _{1 - x} La _x Zr _{1 -y} Ti _y O ₃ (PLZT hafnia, 0 <x <1, 0 <y <1), (1-x) Pb (Mg 1/3 Nb 2/3) O 3 -xPbTiO 3 (PMN-PT, 0 <x <1), ( HfO ₂ ), SrTiO ₃ , SnO ₂ , CeO ₂ , MgO, NiO, CaO, ZnO, ZrO ₂ , SiO ₂ , Y ₂ O ₃ , Al ₂ O ₃ , SiC and TiO ₂ , or any one thereof The separator is a mixture of two or more of them. The method of claim 7, wherein
The inorganic particles having the lithium ion transfer ability are lithium phosphate (Li ₃ PO ₄ ), lithium titanium phosphate (Li _x Ti _y (PO ₄ ) ₃ , 0 <x <2, 0 <y <3), lithium aluminum titanium phosphate (Li _x Al _y Ti _z (PO ₄ ) ₃ , 0 <x <2, 0 <y <1, 0 <z <3), (LiAlTiP) _x O _y series glass (0 <x <4, 0 <y <13), lithium lanthanum titanate (Li _x La _y TiO ₃ , 0 <x <2, 0 <y <3), lithium germanium thiophosphate (Li _x Ge _y P _z S _w , 0 <x <4 , 0 <y <1, 0 <z <1, 0 <w <5), lithium nitride (Li _x N _y , 0 <x <4, 0 <y <2), SiS ₂ (Li _x Si _y S _z , 0 <x <3, 0 <y <2, 0 <z <4) series glass and P ₂ S ₅ (Li _x P _y S _z , 0 <x <3, 0 <y <3, 0 <z <7) Any one selected from the group consisting of series glass or a mixture of two or more thereof. The method of claim 1,
Wherein the binder is selected from the group consisting of polyvinylidene fluoride-co-hexafluoropropylene, polyvinylidene fluoride-co-trichlorethylene, polymethylmethacrylate, poly But are not limited to, polybutyl acrylate, polyacrylonitrile, polyvinylpyrrolidone, polyvinylacetate, polyethylene-co-vinyl acetate, polyethylene oxide Polyarylate, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, cyanoethylpullulan, cyanoethylpolylenes, Vinyl alcohol (cyanoethylpolyvinylalcohol), The separator is any one selected from the group consisting of cyanoethylcellulose, cyanoethylsucrose, pullulan, and carboxyl methyl cellulose, or a mixture of two or more thereof. The method of claim 1,
The content of the porous adsorbent is 5 to 95 parts by weight based on 100 parts by weight of the total of the inorganic particles and the binder polymer. The method of claim 1,
The weight ratio of the inorganic particles and the binder is 50:50 to 99: 1. The method of claim 1,
The thickness of the porous coating layer is a separator of 0.01 to 20㎛. The method of claim 1,
The porous coating layer is a separator further comprising any one or two or more of these additives selected from the group consisting of additives for forming a solid electrolyte interface, battery side reaction inhibitory additives, thermal stability improving additives, and overcharge inhibitory additives. 15. The method of claim 14,
The content of the additive is 2 to 20 parts by weight based on 100 parts by weight of the total of the inorganic particles and the binder. The method of claim 1,
The porous substrate is a separator that is a polyolefin-based porous membrane or a nonwoven fabric. The method of claim 1,
The porous substrate is a high density polyethylene, low density polyethylene, linear low density polyethylene, ultra high molecular weight polyethylene, polypropylene polyethylene terephthalate, polybutylene terephthalate, polyester (polyester), polyacetal, polyamide polyamide, polycarbonate, polyimide, polyetheretherketone, polyethersulfone, polyphenyleneoxide, polyphenylenesulfidro and polyethylenenaphthalene Separator formed from any one selected from the group consisting of (polyethylenenaphthalene) or a mixture of two or more thereof. An electrochemical device comprising a cathode, an anode, and a separator interposed between the cathode and the anode, wherein the separator is the separator of any one of claims 1 to 17. 19. The method of claim 18,
The electrochemical device is a lithium secondary battery.

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