KR101747908B1 - Porous separator, electrochemical device comprising the same, and method of preparing the separator - Google Patents

Abstract

The present invention relates to a porous nonwoven fabric separator, and more particularly, to a porous nonwoven fabric separating membrane including a nonwoven web incorporated into a porous polymeric base material, an electrochemical device including the same, and a method for producing the separator. According to an aspect of the present invention, there is provided a porous polymer electrolyte fuel cell comprising: a porous core unit made of a first polymer; And a second polymer that surrounds the porous core and is bonded to the surface and pores of the porous core and includes inorganic particles having a diameter of 30 nm or less and a second polymer that is located on part or all of the inorganic particles to connect and fix the inorganic particles. a porous nonwoven fabric separator comprising a nonwoven web comprising a conjugate fiber having a diameter of 1,000 nm or less and a sheath portion, wherein the whole or a part of the conjugate fiber is bonded to each other in a fusion-bonded manner. According to another aspect of the present invention, there is provided a method of manufacturing a porous nonwoven fabric separator comprising the steps of forming a porous core portion of a conjugate fiber, forming a slurry, forming a conjugate fiber, and forming a nonwoven web. INDUSTRIAL APPLICABILITY According to the present invention, a porous nonwoven fabric separator having improved mechanical strength, electrolyte wettability, oxidation resistance, and thermal stability while having a small total thickness can be produced.

Description

TECHNICAL FIELD [0001] The present invention relates to a porous separator, an electrochemical device including the separator, and a method of manufacturing the separator,

The present invention relates to a porous separator, and more particularly, to a porous nonwoven fabric separator including a nonwoven web incorporated into a porous polymeric base material, an electrochemical device including the same, and a process for producing the separator.

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. The electrochemical device is one of the most attracting fields in this respect, and development of a secondary battery such as a rechargeable lithium secondary battery has become a focus of attention.

In the separator constituting such a battery, the basic required characteristics thereof are excellent air permeability, low heat shrinkage and high puncture strength, similar to that of the separator for other cells, and are continuously excellent due to the development of high capacity and high output cells The air permeability is further required. However, the porous separator of the secondary battery exhibits extreme heat shrinkage behavior at a temperature of about 100 ° C or more due to the characteristics of the manufacturing process including material properties and elongation, thereby causing a short circuit between the anode and the cathode. In order to solve such a problem of safety of the battery, for example, Korean Patent Publication No. 2007-0083975 (Hitachi) and Korean Patent Laid-Open Publication No. 2007-0019958 (Ebonic) disclose a method for producing a battery comprising a mixture of insulating filler particles and a binder Discloses a separation membrane prepared by adding a substance having a shut-down function to a porous coating layer while providing a porous coating layer formed thereon.

However, in such a separation membrane, since the interface between the porous substrate made of organic material (layer) and the porous coating layer containing insulating filler particles (inorganic particles) is separated as a layer structure, the risk of separation of these layers, And the overall mechanical properties are not greatly improved.

Therefore, a problem to be solved by the present invention is to provide a separation membrane having excellent mechanical properties and thin thickness while maintaining the integrity of the separation membrane.

According to an aspect of the present invention, there is provided a method of manufacturing a semiconductor device, comprising: forming a porous core portion made of a first polymer; And a second polymer that surrounds the porous core and is bonded to the surface and pores of the porous core and includes inorganic particles having a diameter of 30 nm or less and a second polymer that is located on part or all of the inorganic particles to connect and fix the inorganic particles. a porous nonwoven fabric separator comprising a nonwoven web comprising a conjugate fiber having a diameter of 1,000 nm or less and a sheath portion, wherein the whole or a part of the conjugate fiber is bonded to each other in a fusion-bonded manner.

According to another aspect of the present invention, there is provided a method for producing a porous film, comprising: forming a porous core portion of a composite fiber by spinning a spinning solution in which a first polymer is dissolved in a first solvent and removing the first solvent; Forming a slurry by dispersing inorganic particles having a diameter of 30 nm or less in a solution of a second polymer in which the second polymer is dissolved in a second solvent; Forming a coated composite fiber having a diameter of 1,000 nm or less by dipping the porous core portion in the slurry and removing the second solvent therefrom; And forming the coated nonwoven fabric by thermally fusing the coated conjugate fiber at a high temperature to form a nonwoven web in which all or a part of the conjugate fibers are bonded to each other in a fusion-bonded manner.

INDUSTRIAL APPLICABILITY According to the present invention, a porous nonwoven fabric separator having improved mechanical strength, electrolyte wettability, oxidation resistance, and thermal stability while having a small total thickness can be produced.

1 is an example of a cross-sectional view of a porous nonwoven fabric separating membrane produced according to one embodiment of the present invention.
2 is a schematic flow chart of a method of manufacturing a porous nonwoven fabric separator according to an embodiment of the present invention.
Figure 3 is a schematic representation of a portion of Figure 2;

Hereinafter, the present invention will be described in detail. Prior to this, 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 designate the concept of a term appropriately in order to describe its own invention in the best way possible. It should be interpreted as meaning and concept consistent with the technical idea of the present invention. Therefore, the embodiments described in this specification and the configurations shown in the drawings are merely the most preferred embodiments of the present invention and do not represent all the technical ideas of the present invention. Therefore, It is to be understood that equivalents and modifications are possible.

According to an aspect of the present invention, there is provided a porous nonwoven fabric separating membrane comprising a nonwoven web made of conjugate fibers having a core-sheath structure in which inorganic particles are mixed in a sheath portion.

1 is an example of a cross-sectional view of a porous nonwoven fabric separating membrane produced according to one embodiment of the present invention. Referring to FIG. 1, the porous nonwoven fabric separator of the present invention is as follows but is not limited thereto.

The term nonwoven web as used herein refers to a nonwoven web in which the fibrous aggregate is subjected to chemical action (e. G., By mixing the adhesive in the fiber), by mechanical action or by suitable moisture and heat treatment, ) ≪ / RTI >

The nonwoven web is bonded to the whole or a part thereof in a fusion-bonded manner. Such fusion can be achieved by heat at high temperature upon spinning of the spinning solution during the manufacturing process of the nonwoven web. Such a nonwoven web is made of conjugated fibers. The composite fiber has a cross section of a core-sheath structure, that is, a core portion and a sheath portion surrounding the core portion.

The core portion has a porous structure having a plurality of pores, and is made of the first polymer. Non-limiting examples of the first polymer include polypropylene, polyethyleneterephthalate, polyester, polyacetal, polyamide, polycarbonate, polyimide, Polyetheretherketone, polyetherimide, polyamideimide, polyethersulfone, polyphenyleneoxide, polyphenylenesulfide, and polyethylene naphthalene (also referred to as " polyethylenenaphthalene), or a mixture of two or more thereof.

Such a core portion may be made of a material usable in a non-nonsense-induced phase separation method, such as polypropylene and polyethylene terephthalate, in order to easily realize porosity at its surface while providing mechanical strength and thermal stability such as tensile strength thereof. It is more preferable to use one or a mixture of two or more selected from the group consisting of polyethyleneterephthalate.

The sheath portion surrounds the porous core portion and includes the surface of the core portion and the inside of the pore thereof. Further, the sheath portion includes inorganic particles and a second polymer.

The inorganic particles are not particularly limited as long as oxidation and / or reduction reaction does not occur in the operating voltage range of the applied electrochemical device (for example, about 0 to about 5 V based on Li / Li ⁺ ). Particularly, when inorganic particles having a high dielectric constant are used as the inorganic particles, the dissociation of the electrolyte salt, for example, the lithium salt in the liquid electrolyte, can be increased, and the ion conductivity of the electrolyte can be improved.

Although the kind of the inorganic particles is not particularly limited, inorganic particles selected from the group consisting of inorganic particles having a dielectric constant of about 5 or more, inorganic particles having a lithium ion transferring ability (in the case of a lithium secondary battery), and mixtures thereof may be used . As the dielectric constant is about five or more inorganic particles is _{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, 0 <x <1 , 0 <y <1), (1-x) Pb (Mg 1/3 Nb 2/3) O 3 -xPbTiO 3 (PMN-PT, 0 <x <1), the half It is preferable to use 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 , But is not limited thereto. As the inorganic particles having lithium ion transferring ability, 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), (LiAlTiP) _x O _y series glass 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 , x <4, 0 <y < 1, 0 <z <1, 0 <w <5), lithium nitrides _{(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) based glass, and _{P 2 S 5 (Li x P} y S z, 0 <x <3, 0 <y <3, 0 < z < 7) series glass or the like is preferably used, but is not limited thereto.

The inorganic particles preferably have a diameter of 30 nm or less. More preferably, inorganic particles having a diameter of about 10 to about 20 nm can be used. The inorganic particles having a diameter within this range are bonded to the second polymer to be described later by, for example, crosslinking or the like, and are bonded to the surface and pores of the porous core portion, whereby the inorganic particles can be advantageously used for the mechanical properties and wettability have. However, in the case of having a diameter exceeding the above-mentioned range, it is difficult to achieve the structural stability due to the incorporation into the sheath portion of the composite fiber and the bonding with the first molecule and / or the second polymer of the core portion.

Non-limiting examples of the second polymer include polyethylene, polypropylene, polyethyleneterephthalate, polybutyleneterephthalate, polyester, polyacetal, polyamide, polyamide, polyamide, polycarbonate, polyimide, polyetheretherketone, polyaryletherketone, polyetherimide, polyamideimide, polybenzimidazole, polybenzimidazole, polyethersulfone, polyphenylene oxide, cyclic olefin copolymer, polyphenylenesulfide, and polyethylenenaphthalene. The polyphenylene sulfide may be selected from the group consisting of polybenzimidazole, polyethersulfone, polyphenylene oxide, Or a mixture of two or more.

The sheath portion of the composite fiber further includes a silane-based coupling agent. Such a silane-based coupling agent can promote the bonding of the inorganic particles of the sheath portion and the second polymer. Examples of the silane coupling agent include, but are not limited to, vinyl silane, acrylic silane, amino silane, chloro silane, phenoxy silane, acrylate silane, preferably vinyl silane, methacrylate silane and acrylate silane And mixtures of two or more thereof.

The inorganic particles of the sheath portion of the composite fiber and the second polymer may be crosslinked with each other. This cross-linking can be achieved by heat or light. The crosslinking of the composite fibers can further enhance the structural stability of the porous nonwoven fabric separator.

The diameter of such a composite fiber may be about 1,000 nm or less, preferably about 200 to about 1,000 nm. The nonwoven web having a diameter in the above-mentioned range can further reinforce the air permeability and mechanical strength of the nonwoven web bonded to each other by fusion bonding as described above. However, if the diameter of the composite fibers exceeds the above-mentioned range, the voids or pores formed by the composite fibers of the nonwoven web become too narrow, adversely affecting the air permeability of the porous nonwoven fabric separation membrane containing the web. On the contrary, if the diameter of the composite fibers is less than the above-mentioned range, the tensile strength formed by the composite fibers of the nonwoven web becomes too weak, which adversely affects the mechanical strength of the porous nonwoven fabric separating film containing the web.

In the porous nonwoven fabric separator, the cross-sectional area of the porous core portion may be about 10 to about 90% of the total cross-sectional area of the conjugate fiber. In the porous nonwoven fabric separator, if the cross-sectional area of the porous core portion falls within the above-mentioned range, the desired excellent mechanical strength of the present invention can be achieved.

According to another aspect of the present invention, an electrochemical device including the positive electrode, the negative electrode, and the above-described separator interposed between the positive electrode and the negative electrode may be manufactured. The electrochemical device of the present invention includes all devices that perform an electrochemical reaction. Examples of the electrochemical device include capacitors such as all types of primary cells, secondary cells, fuel cells, solar cells, and super capacitors. Particularly, 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 is preferable among the above secondary batteries.

The anode, the cathode and the like can be easily produced by a process and / or a method known in the art.

The anode is prepared by binding a cathode active material to a cathode current collector according to a conventional method known in the art. As the cathode active material, a conventional cathode active material that can be used for a cathode of a conventional electrochemical device can be used. Examples of the cathode active material include LiCoO ₂ , LiNiO ₂ , LiMnO ₂ , LiMn ₂ O ₄ , Li (Ni _a Co _{b Mn c) O 2 (0 <} a <1, 0 <b <1, a + b + c = 1), LiNi 1 -Y Co Y O 2, LiCo 1 - Y Mn Y O 2, LiNi 1 -Y Mn _Y O ₂ (where, 0≤Y <1), Li ( Ni a Co b Mn c) O 4 (0 <a <2, 0 <b <2, a + b + c = 2), LiMn 2 - Z Ni _Z O ₄ , LiMn _{2 -Z} Co _Z O ₄ (where 0 <Z <2), LiCoPO ₄ , LiFePO _4, and mixtures thereof. The anode current collector may be made of aluminum, nickel, or a combination thereof.

The negative electrode is prepared by adhering the negative electrode active material to the negative electrode current collector according to a conventional method known in the art. At this time, the negative electrode active material may be carbon such as non-graphitized carbon or graphite carbon; Li _x Fe ₂ O ₃ (0? _X? 1), Li _x WO ₂ (0? _X? 1), Sn _x Me _{1 -x} Me _y O _z (Me: Mn, Fe, Pb, : Metal complex oxides of Al, B, P, Si, Group 1, Group 2, Group 3 elements of the periodic table, halogen, 0 &lt; x &lt; Lithium metal; Lithium alloy; Silicon-based alloys; Tin alloy; _{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, GeO 2, Bi 2 O 3, Bi 2 O 4, Bi ₂ O ₅ and the like; Conductive polymers such as polyacetylene; Li-Co-Ni-based materials and the like can be used. On the other hand, as the negative electrode current collector, stainless steel, nickel, copper, titanium or an alloy thereof can be used.

Also, the electrolyte that can be inserted between the electrode and the separator is a salt having a structure such as A ⁺ B ^- , where A ⁺ includes an alkali metal cation such as Li ⁺ , Na ⁺ , K ⁺ and B ^- 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 - (PC), ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), and the like, and salts containing anions such as C (CF ₂ SO ₂ ) ₃ ^- But are not limited to, dipropyl carbonate (DPC), dimethylsulfoxide, acetonitrile, dimethoxyethane, diethoxyethane, tetrahydrofuran, N-methyl-2-pyrrolidone (NMP), ethylmethyl carbonate (? -butyrolactone), or a mixture thereof, but is not limited thereto All.

The electrolyte may be injected at an appropriate stage of the battery manufacturing process, depending on the manufacturing process and required properties of the final product. As a process for applying the separator 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 process of winding.

According to another aspect of the present invention, there is provided a method of forming a porous core, comprising: (S1) forming a porous core portion; A step (S2) of forming a slurry; Forming a composite fiber (S3); And a step (S4) of forming a nonwoven web.

2 is a schematic flow chart of a method of manufacturing a porous nonwoven fabric separator according to an embodiment of the present invention. 3 is a schematic view of part of FIG. A method of manufacturing the porous nonwoven fabric separator of the present invention will be described with reference to FIGS. 2 and 3. FIG.

In step S1, a spinning solution of the first polymer is prepared. Here, the spinning solution of the first polymer is formed by dissolving the first polymer (particle) in the first solvent. The first solvent preferably has a solubility index similar to that of the polymer used and a low boiling point. Here, the first polymer is as described in the description of the separator of the present invention.

Using the spinning liquid of the first polymer thus formed, the fibers are spun as core portions of the composite fibers. Here, the spinning solution of the first polymer may be formed by one method selected from the group consisting of spinning methods known in the art, for example, melt spinning, solution spinning, electrospinning, or a combination of two or more thereof For example, to a collector.

The core part removes the solvent by means of non-solvent, heating, evaporation, etc., and the core part from which the solvent is removed has a porous structure. Here, the non-solvent induced phase separation (NIPS) using a non-solvent is a method in which a solution is formed by dissolving a first polymer in a first solvent, molding the solution into a predetermined form, , But not limited to, water, alcohol such as ethanol, etc.). Thereafter, the nonwoven fabric and the solvent are exchanged by diffusion, the composition of the spinning solution is changed, and the portion of the solvent and non-solvent occupied by the polymer is precipitated as pores.

In addition, the above-mentioned spinning solution may further include a pore-forming agent customary in the art to promote pore formation of the core portion of the subsequently formed composite fiber. Represents the heterogeneity of the fibers (the core portion of the composite fibers) dispersed in the first polymer and formed through the irradiation, etc., and is a substance which is subsequently removed from such fibers. Therefore, the portion where the pore-forming agent is located in the fiber (core portion) remains in the form of pores. The pore former is preferably a liquid material in the extrusion process, but a material that maintains a solid state may be used.

The pore-forming agent may be an aliphatic hydrocarbon-based solvent such as liquid paraffin, paraffin oil, mineral oil or paraffin wax; Vegetable oils such as soybean oil, sunflower oil, rapeseed oil, palm oil, palm oil, coconut oil, corn oil, grape seed oil, cotton seed oil and the like; Or a plasticizer such as a dialkyl phthalate. In particular, the plasticizer is selected from the group consisting of di-2-ethylhexyl phthalate (DOP), di-butyl phthalate (DBP), di- isononyl phthalate Di-isodecyl phthalate (DIDP), butyl benzyl phthalate (BBP), and the like.

The content of the pore-forming agent is generally required to be high in order to improve the bonding force with the sheath portion, that is, the degree of porosity (i.e., porosity) of the core portion to which the second polymer of the sheath portion comes into contact, If such an excessive amount is contained, the porosity of the core portion may be improved, but the mechanical strength of the porous nonwoven fabric separation membrane finally formed may be adversely affected due to the lowering of the tensile strength of the core portion. Therefore, the content of the pore-forming agent required according to one aspect of the present invention can be appropriately reduced.

Further, when a porogen is further used, the removal of the porogen may be accomplished using a second solvent. Specifically, the pore-former present in the layer is removed, for example, by extraction and drying with a second solvent in one or more extraction tanks. In addition, through this removal, the space occupied by the pore former is formed as pores. The second solvent usable in the present invention is not particularly limited and any solvent capable of extracting the pore forming agent used for extrusion can be used. Preferably, the solvent is methyl ethyl ketone, methylene chloride methylene chloride, hexane and the like are suitable. The extraction method can be used in combination with all common solvent extraction methods such as immersion method, solvent spray method, ultrasonic method and the like.

In step S2, a solution of the second polymer is formed by dissolving the second polymer in a second solvent. A slurry is formed by dispersing inorganic particles in a solution of the second polymer. The second polymer and the inorganic particles are as described in the description of the separator of the present invention. The second solvent is preferably similar to the first solvent and has a solubility index similar to that of the polymer and has a low boiling point.

The first and second solvents may each independently be selected from the group consisting of non-limiting examples thereof such as acetone, tetrahydrofuran (THF), dioxane, monoglyme, diglyme, Dimethyl sulfoxide (DMSO), dimethyl acetamide (DMAC), chloroform, dimethyl formamide (DMF), N-methyl-2-pyrrolidone N-methylpyrrolidone (NMP), normal hexane, cyclohexane, benzene, toluene, chlorobenzene, dichlorobenzene, methylene chloride, Dichloroethane, 2-dichloroethane, or mixtures thereof. Preferably, the solvent is selected from the group consisting of dimethyl acetamide (DMAC), chloroform, dimethyl formamide (DMF), N-methyl-2-pyrrolidone Mixtures thereof. These solvents may preferably be similar to the solubility index of the solute to be dissolved, i.e., the first polymer or the second polymer. The concentration of the solvent may be selected depending on the chemical structure or the molecular weight of the first polymer or the second polymer selected.

When the first polymer or the second polymer is a hydrophobic compound, a hydrophilic treatment is required.

Alternatively, the slurry may further comprise a silane-based coupling agent. Examples of the silane coupling agent include, but are not limited to, vinyl silane, acrylic silane, amino silane, chloro silane, phenoxy silane, acrylate silane, preferably vinyl silane, methacrylate silane and acrylate silane And mixtures of two or more thereof.

The slurry may further comprise a silica precursor. Examples of the silica precursor include a mixture of one or more selected from the group consisting of tetramethoxyorthosilicate (TMOS) and tetraethoxyorthosilicate (TEOS) .

Further, the slurry may further comprise one or a mixture of two or more selected from the group consisting of a radical initiator, a curing initiator, and an acid or base catalyst treating agent. Examples of the radical initiator include benzoyl peroxide, di-tributyl peroxide, azobisisobutyronitrile, tributyl hydroperoxide, dicumyl peroxide, t-butyl perbenzoate, cumene hydroperoxide, t- Ethyl ethyl ketone peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, lauryl peroxide and the like can be used.

In step S3, the porous core formed in step S1 is dipped in the slurry formed in step S2. Due to this immersion process, a sheath surrounding the porous core portion is formed, at which time the slurry penetrates into the surface and pores of the porous core portion. Generally, in the slurry, the second polymer remains in the pores of the core portion and bonds. However, some fine inorganic particles penetrate into the pores of the core portion to be positioned or bonded to each other. (See FIG. 3).

The second solvent is then removed from the slurry coated around the porous core to form the coated composite fibers. Here, the diameter of the coated composite fiber may be about 1,000 nm or less, preferably about 200 to about 1,000 nm, as described hereinbefore in the description of the separator.

In step S4, the composite fibers formed in step S3 are thermally fused at a high temperature.

The formed composite fibers may be formed by a method of forming a nonwoven web known in the art, such as dry laid, wet laid, spun bonded, spun laced, , Melt blown or the like to form a nonwoven web.

The formed nonwoven web is thermally fused at a high temperature. Here, the high temperature means a temperature at which at least a part of the second polymer of the nonwoven web is melted and can melt-bond with the surface of the adjacent nonwoven web, in particular, another second polymer. Thus, The temperature range, if present under the conditions, is not particularly limited. The temperature for the thermal fusion is a temperature range between the temperature at which the conjugated fiber (second polymer) to be used can be partially melted or tackified, that is, the temperature between the glass transition temperature of the second polymer used and the melting point of the second polymer desirable. However, those skilled in the art will appreciate that depending on the time the heating means is external and the heating temperature is applied, the temperature above the melting point of the second polymer will be possible for a certain period of time.

Such thermal fusion bonding is performed by heat fusion bonding through a conventional thermal fusion bonding method such as thermocompression bonding in the related art. The heat fusion is performed by fusing the fibers under conditions such as heating temperature, heating time, pressure and the like suitable for fusing each other, whereby all or part of the fibers are fused (bonded) to each other. Such nonwoven webs can also reinforce the bonds between the fibers through methods known in the art, such as needle punching, mechanical processes, use of adhesives, etc., to form nonwoven webs with better tensile strength . The nonwoven web thus formed has a porous structure having a plurality of pores in a space between the conjugate fibers, and the bonding force between the fibers is greatly increased by fusion, thereby increasing the tensile strength of the entire nonwoven web.

Claims (15)

A porous core portion made of a first polymer; And
And a second polymer that surrounds the porous core and is bonded to the surface and the pores of the porous core and includes inorganic particles having a diameter of 30 nm or less and a second polymer positioned on a part or all of the inorganic particles to connect and fix the inorganic particles. sheath
And having a diameter of 1,000 nm or less, wherein the whole or a part of the composite fibers are bonded to each other in a fusion-bonded manner. The method according to claim 1,
Wherein the first polymer is selected from the group consisting of polypropylene, polyethylene terephthalate, polyester, polyacetal, polyamide, polycarbonate, polyimide, And is made of polyetheretherketone, polyetheretherketone, polyetherimide, polyamideimide, polyethersulfone, polyphenyleneoxide, polyphenylenesulfide, and polyethylenenaphthalene. Wherein the porous nonwoven fabric separator is a mixture of at least one selected from the group consisting of polyolefin, The method according to claim 1,
Wherein the second polymer is selected from the group consisting of polyethylene, polypropylene, polyethylene terephthalate, polybutylene terephthalate, polyester, polyacetal, polyamide, But are not limited to, polycarbonate, polyimide, polyetheretherketone, polyaryletherketone, polyetherimide, polyamideimide, polybenzimidazole, One or more types selected from the group consisting of polyethersulfone, polyphenylene oxide, cyclic olefin copolymer, polyphenylenesulfide and polyethylene naphthalene, A porous nonwoven fabric Rimak. The method according to claim 1,
Wherein the inorganic particles further comprise inorganic particles selected from the group consisting of inorganic particles having a dielectric constant of 5 or more, inorganic particles having a lithium ion transporting ability, and mixtures thereof. The method according to claim 1,
The porous nonwoven fabric separating membrane according to claim 1, further comprising a silane coupling agent. 6. The method of claim 5,
Wherein the silane coupling agent is a mixture of at least one selected from the group consisting of vinyl silane, methacrylate silane, and acrylate silane. The method according to claim 1,
Wherein the inorganic particles of the sheath portion and the second polymer are crosslinked with each other. The method according to claim 1,
Wherein the inorganic particles of the sheath portion and the second polymer are crosslinked with each other by heat or light. An electrochemical device comprising a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode,
The electrochemical device according to any one of claims 1 to 8, wherein the separator is a porous nonwoven fabric separator. 10. The method of claim 9,
Wherein the electrochemical device is a lithium secondary battery. Forming a porous core portion of the composite fiber by spinning a spinning solution in which the first polymer is dissolved in a first solvent and removing the first solvent from the spinning solution;
Forming a slurry by dispersing inorganic particles having a diameter of 30 nm or less in a solution of a second polymer in which the second polymer is dissolved in a second solvent;
Forming a coated composite fiber having a diameter of 1,000 nm or less by dipping the porous core portion in the slurry and removing the second solvent therefrom; And
Forming a nonwoven web in which all or a part of the composite fibers are bonded to each other in a fusion-bonded manner by thermally fusing the coated composite fibers at a high temperature
Wherein the porous nonwoven fabric separator comprises a porous nonwoven fabric. 12. The method of claim 11,
The spinning method used in the step of forming the porous core portion of the composite fiber is one of the methods selected from the group consisting of melt spinning, solution spinning and electro-spinning, or a combination of two or more thereof Wherein the porous nonwoven fabric separator comprises a porous nonwoven fabric. 12. The method of claim 11,
Wherein the first solvent and the second solvent are each independently selected from the group consisting of acetone, tetrahydrofuran (THF), dioxane, monoglyme, diglyme, dimethyl dimethylformamide (DMF), N-methyl-2-pyrrolidone (NMP), and the like. Normal hexane, cyclohexane, benzene, toluene, chlorobenzene, dichlorobenzene, methylene chloride, 1,2-dichloroethane (such as dichloromethane, 1,2-dichloroethane) or a mixture thereof. 12. The method of claim 11,
Wherein the spinning liquid further comprises a pore-forming agent. A porous nonwoven fabric separator produced by the method for producing a porous nonwoven fabric separator according to any one of claims 11 to 14.

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