KR20150047875A - Separator for lithium secondary battery and lithium secondary battery comprising the same - Google Patents

Abstract

Provided are a separator for a lithium secondary battery and the lithium secondary battery comprising the same. Small pores of a non-woven fabric material are filled with ceramic nanoparticles with lithium ion conductivity, and large pores of the non-woven fabric material are filled with ceramic microparticles, so the resistance leveled toward the surface direction of the non-woven fabric material is formed.

Description

TECHNICAL FIELD [0001] The present invention relates to a separator for a lithium secondary battery and a lithium secondary battery including the lithium secondary battery,

The present invention relates to a separator for a lithium secondary battery and a lithium secondary battery including the separator. More specifically, ceramic nanoparticles of lithium ion conductivity are embedded in small pores of the nonwoven fabric substrate and ceramic microparticles are embedded in large pores of the nonwoven fabric substrate And has resistance leveled in the direction of the surface of the nonwoven fabric substrate, and a lithium secondary battery including 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.

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 in using an organic electrolytic solution, and has a disadvantage that it is difficult to manufacture.

In order to secure the safety of such a lithium secondary battery, a separation membrane having a porous coating layer formed by coating a mixture of inorganic particles and a binder polymer on at least one surface of a porous substrate having a plurality of pores has been proposed. However, when the nonwoven fabric is used as the porous substrate of such a separator, the resistance in the plane direction is not constant, the thickness is not constant, and electrolyte impregnation is also not uniform.

Therefore, a problem to be solved by the present invention is to solve the problem of uneven resistance occurring when a nonwoven fabric is used as a separator substrate. Further, the problem of non-uniform thickness occurring when a nonwoven fabric is used as a separator base material is solved. In addition, the problem of non-uniformity of electrolyte impregnation that occurs when a nonwoven fabric is used as a separator base material is also addressed.

According to an aspect of the present invention for solving the above-mentioned problems, there is provided a nonwoven fabric comprising: (a) a nonwoven substrate having pores; And (b) a porous coating layer located on at least one side of the nonwoven substrate and including ceramic particles and a binder polymer, wherein the ceramic particles are connected and fixed to each other by the binder polymer, and interstitial between the ceramic particles Wherein the ceramic particles have ceramic microparticles having a small average particle diameter and ceramic microparticles having a large average particle diameter.

The ceramic nanoparticles may have an average particle diameter of 1 to 100 nm.

The ceramic microparticles may have an average particle diameter of 20 to 100 mu m.

The pores of the nonwoven fabric may have a maximum diameter of 0.1 to 70 μm, and the pores may account for 50% or more of the total number of nonwoven fabric pores.

The ceramic nanoparticles may have a dielectric constant of 5 or more.

Wherein the ceramic nanoparticles are selected from the group consisting of BaTiO ₃ , Pb (Zr, Ti) O ₃ (PZT), Pb _{1 - x} La _x Zr _{1 - y} Ti _y O _{3 Lim), Pb (Mg 1/3} Nb 2/3) O 3 -PbTiO 3 (PMN-PT), hafnia (HfO ₂ ), SrTiO ₃ , SnO ₂ , CeO ₂ , MgO, NiO, CaO, ZnO, ZrO ₂ , Y ₂ O ₃ , Al ₂ O ₃ , TiO ₂ , SiC, Lt; / RTI >

The ceramic microparticles is a lithium phosphate (Li ₃ PO _4), lithium titanium phosphate _{(LixTiy (PO 4) 3,} 0 <x <2, 0 <y <3), lithium aluminum titanium phosphate (LixAlyTiz (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 0 < y < 1, 0 < z < 1, TiO ₃ , 0 <x <2, 0 <y <3), lithium germanium thiophosphate (Li _x Ge _y P _z S _w , 0 <w <5), lithium nitride (Li _x N _y , 0 <x <4, 0 <y <2), SiS ₂ series glass (Li _x Si _y S _z , <it may be a 2, 0 <z <4) , 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.

The nonwoven substrate may be formed of a material selected from the group consisting of polyolefins such as polyethylene and polypropylene, polyethylene terephthalate, polyester, polyamide, polyacetal, polycarbonate, polyimide, polyetheretherketone, polyether sulfone, polyphenylene oxide and polyphenylene sulfide , Polyethylene naphthalene, or mixtures thereof.

According to another aspect of the present invention, there is provided a lithium secondary battery comprising a negative electrode, a positive electrode, and a separator interposed between the negative electrode and the positive electrode, wherein the separator is the separator for the lithium secondary battery described above do.

According to another aspect of the present invention, there is provided a method of manufacturing a nonwoven substrate, comprising the steps of: preparing a nonwoven substrate having pores; applying ceramic nanoparticles and ceramic microparticles to the nonwoven substrate; and drying the ceramic nanoparticles and the ceramic microparticle- A method for producing a separator for a lithium secondary battery comprising the steps of:

A mixture of ceramic nanoparticles and ceramic microparticles can be applied to a nonwoven substrate after the binder polymer is dissolved in a solution.

The ceramic nanoparticles may be dispersed in a solution in which the binder polymer is dissolved and then applied to the nonwoven substrate, and then the ceramic microparticles may be dispersed in the binder polymer solution to be applied to the nonwoven substrate.

The ceramic nanoparticles, ceramic microparticles or mixtures of the two in the solution may have a low solids content.

The separator for a lithium secondary battery of the present invention exhibits the following effects:

First, lithium ion conductive ceramic nanoparticles are contained in relatively small-sized pores of the nonwoven fabric to lower the resistance, and ceramic microparticles are contained in relatively large pores to increase the resistance. As a result, resistance to the nonwoven fabric surface direction The leveling effect is obtained.

Second, the inclusion rate of the ceramic particles in the nonwoven fabric pores is increased, and the difference in the impregnation degree of the electrolyte caused by the variation of the pore size is reduced.

Third, since the ceramic nanoparticles are embedded in small-sized pores of the nonwoven fabric substrate, ceramic microparticles are embedded in large-sized pores of the nonwoven fabric substrate and overcoated on the nonwoven fabric surface, .

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 should appropriately interpret the concepts of the terms appropriately It should be interpreted in accordance with the meaning and concept consistent with the technical idea of the present invention based on the principle that it can be defined. Therefore, the constitutions described in the embodiments described herein are merely the most preferred embodiments of the present invention, and are not intended to represent all of the technical ideas of the present invention. Therefore, various equivalents which can be substituted at the time of application It should be understood that variations can be made.

The separator for a lithium secondary battery of the present invention comprises (a) a nonwoven substrate having pores; And (b) a porous coating layer located on at least one side of the nonwoven substrate and including ceramic particles and a binder polymer, wherein the ceramic particles are connected and fixed to each other by the binder polymer, and interstitial between the ceramic particles Wherein the ceramic particles have ceramic microparticles having a small average particle diameter and ceramic microparticles having a large average particle diameter. As used herein, the term 'interstitial volume' refers to a space defined by ceramic particles that are substantially interfaced with a closed packed or densely packed structure.

The separation membrane of the present invention has a nonwoven base material having pores. The insulating property to both electrodes is maintained due to the nonwoven fabric substrate.

The nonwoven fabric substrate can be used as long as it is usually used as a base material of a separator. The microfibers forming the nonwoven fabric substrate include polyolefins such as polyethylene and polypropylene, polyesters such as polyethylene terephthalate and polybutylene terephthalate, But are not limited to, polyamide, polyacetal, polycarbonate, polyimide, polyether ether ketone, polyethersulfone, polyphenylene oxide, polyphenylene sulfide, polyethylene naphthalene and the like. In particular, in order to improve the heat stability of the nonwoven fabric substrate, the melting point of the microfine fiber is preferably 200 ° C or higher. The thickness of the nonwoven base material is preferably 9 to 30 탆.

The nonwoven fabric may have a pore diameter ranging from 0.1 to 70 μm in the longest diameter (long diameter) of the pores by 50% or more based on the total number of pores, using microfine fibers having an average thickness of 0.5 to 10 μm, more preferably 1 to 7 μm As shown in FIG. It is difficult to manufacture nonwoven fabrics having many pores having a long diameter of less than 0.1 μm, and when the long diameter of the pores exceeds 70 μm, there may arise a problem of lowering the insulating property due to the pore size. However, due to the nature of the nonwoven fabric, the size of the pores is non-uniform. According to the study of the present inventors, due to the uneven pore size, relatively large resistance occurs in relatively small pores, A relatively small resistance is generated in the pores of the size, and a flux is formed toward the pores having a relatively large size, so that the lithium movement in the plane direction is not uniform. In addition, since the impregnation degree of the electrolyte varies depending on the pore size, the battery performance may be deteriorated as a whole due to unevenness in electrolyte concentration.

According to the present invention, two kinds of ceramic particles having different physical parameters are used in order to solve the problem of resistance deterioration due to nonuniform pore size of the nonwoven fabric pores and deterioration of cell performance due to variation in electrolyte impregnation degree.

More specifically, the ceramic particles are composed of ceramic nanoparticles having a small average particle diameter and ceramic microparticles having a large average particle diameter.

The ceramic nanoparticles having a small average particle size tend to be smaller than the average particle size of the pores present in the nonwoven fabric, so that the relatively small pores existing in the nonwoven fabric are filled. The average particle diameter of the ceramic nanoparticles according to the present invention is not limited as long as the above-mentioned object can be achieved, for example, 1 to 100 nm.

The ceramic nanoparticles are preferably filled in the relatively small pores of the nonwoven fabric to have a high dielectric constant in order to lower the resistance. For example, the ceramic nanoparticles are preferably high-permittivity ceramic particles having a dielectric constant of 5 or more, and preferably 10 or more. Nonlimiting examples of ceramic particles having a dielectric constant of 5 or more include BaTiO ₃ , Pb (Zr, Ti) O ₃ (PZT), Pb _{1 - x} La _x Zr _{1 - y} Ti _y O ₃ (PLZT, <1, 0 <y <1 _{Im), Pb (Mg 1/3} Nb 2/3) O 3 -PbTiO 3 (PMN-PT), hafnia (HfO ₂ ), SrTiO ₃ , SnO ₂ , CeO ₂ , MgO, NiO, CaO, ZnO, ZrO ₂ , Y ₂ O ₃ , Al ₂ O ₃ , TiO ₂ , SiC, And mixtures thereof.

The ceramic microparticles should be larger than the pores present in the nonwoven fabric. For example, the ceramic microparticles may have an average particle size of 20 to 100 mu m. Ceramic microparticles of this size are not incorporated into relatively small sized pores present in the nonwoven, but are incorporated into relatively large sized pores of the nonwoven or overcoated onto the nonwoven surface. Nonlimiting examples of the ceramic microparticles include lithium phosphate (Li ₃ PO ₄ ), lithium titanium phosphate (LixTiy (PO ₄ ) ₃ , 0 <x <2, 0 <y <3), lithium aluminum titanium phosphate (LiAlTiP) _x O _y series glass such as 14Li ₂ O-9Al ₂ O ₃ -38TiO ₂ -39P ₂ O ₅ and the like ( ₄ ) ₃ , 0 <x <2, 0 <y < 0 <x <4, 0 <y <13), lithium lanthanum titanate (Li _x La _y TiO ₃ , 0 <x <2, 0 <y <3), Li _{3 .25} Ge _{0 .25} P _{0 .75} lithium, such as S ₄ germanium Mani help thiophosphate _{(Li x Ge y P z S} w, 0 <x <4, 0 <y <1, 0 <z <1, 0 <w <5), Li 3 N , such as lithium nitride _{(Li x N y, 0 <} x <4, 0 <y <2), Li 3 PO 4 -Li 2 S-SiS 2 SiS 2 based _{glass (Li x Si y S z} , 0 <x , such as <3, 0 <y <2 , 0 <z <4), LiI-Li 2 SP 2 S 5 P 2 S 5 based, such as _{glass (Li x P y S z} , 0 <x <3, 0 <y < 3, 0 < z < 7), or a mixture thereof.

The aforementioned ceramic nanoparticles, ceramic microparticles or a mixture of ceramic nanoparticles and ceramic microparticles are mixed with the binder polymer to form a porous coating layer on the nonwoven substrate.

The porous coating layer includes a mixture of the above-described ceramic nanoparticles, ceramic microparticles or a binder polymer together with a mixture of ceramic nanoparticles and ceramic microparticles. The ceramic nanoparticles fill relatively small pores of the nonwoven substrate and the ceramic microparticles are overcoated after filling the relatively large pores of the nonwoven substrate so that a porous coating layer is formed on the nonwoven substrate to form a uniform nonwoven film thickness. The ceramic particles contained in the porous coating layer are connected and fixed to each other by the binder polymer, and the pores formed due to the interstitial volume between the ceramic particles are present in the porous coating layer.

The binder polymer contained in the porous coating layer may be a polymer commonly used in the art to form a porous coating layer on a nonwoven substrate.

The binder polymer is preferably a polymer having a glass transition temperature (T _g ) of -200 to 200 ° C. This improves the mechanical properties such as flexibility and elasticity of the finally formed porous coating layer It is because. Such a binder polymer serves as a binder for connecting and stably fixing ceramic particles or between ceramic particles and a nonwoven substrate.

Further, the binder polymer does not necessarily have the ion-conducting ability, but the performance of the lithium secondary battery can be further improved when a polymer having ion-conducting ability is used. Therefore, it is preferable that the binder polymer has a high permittivity constant. In fact, since the dissociation degree of the salt in the electrolyte depends on the permittivity constant of the electrolyte solvent, the higher the permittivity constant of the binder polymer, the better the salt dissociation in the electrolyte. The dielectric constant of such a binder polymer may be in the range of 1.0 to 100 (measurement frequency = 1 kHz), preferably 10 or more.

In addition to the functions described above, the binder polymer may be characterized by being capable of exhibiting a high degree of swelling of the electrolyte by being gelled upon impregnation with a liquid electrolyte. Accordingly, it is preferable to use a solubility parameter of 15 to 45 MPa ^1/2 of a polymer, and the more preferred solubility parameter of 15 to 25 MPa ^1/2, and 30 to 45 MPa ^1/2 range. Therefore, it is preferable to use hydrophilic polymers having many polar groups, rather than hydrophobic polymers such as polyolefins. If the solubility is more than 15 MPa ^1/2 and less than 45 MPa ^1/2, it is difficult to be impregnated with (swelling) by conventional liquid electrolyte batteries.

Non-limiting examples of such polymers include polyvinylidene fluoride-co-hexafluoropropylene, polyvinylidene fluoride-trichlorethylene, polymethyl methacrylate polymethylmethacrylate, polyacrylonitrile, polyvinylpyrrolidone, polyvinylacetate, polyethylene-co-vinyl acetate, polyethylene oxide, cellulose acetate cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, cyanoethylpullulan, cyanoethylpolyvinylalcohol, cyanoethylcellulose (also referred to as &quot; cyanoethylcellulose, Ethyl sucrose (cyanoethylsucrose), and the like pullulan (pullulan), carboxymethyl cellulose (carboxyl methyl cellulose).

The composition ratio of the ceramic nanoparticles, the ceramic microparticles or the mixture of the ceramic nanoparticles and the ceramic microparticles and the binder polymer in the porous coating layer coated on the nonwoven fabric substrate according to the present invention is preferably in the range of, for example, 50:50 to 99: 1 , More preferably from 70:30 to 95: 5. When the content ratio of the ceramic particles to the binder polymer is less than 50:50, the content of the polymer is increased and the pore size and porosity of the porous coating layer may be reduced. If the content of the ceramic particles exceeds 99 parts by weight, the fillerability of the porous coating layer may be weakened because the content of the binder polymer is small.

The loading amount of the porous coating layer on the nonwoven fabric substrate is preferably 5 to 20 g / m ² in consideration of the function of the porous coating layer and suitability for a high capacity battery. The pore size and porosity of the porous coating layer are not particularly limited, but the pore size is preferably in the range of 0.001 to 10 um, and the porosity is preferably in the range of 10 to 90%. The pore size and porosity mainly depend on the size of the ceramic particles. For example, when ceramic particles having a particle size of 1 μm or less are used, pores formed are also about 1 μm or less. Such a pore structure is filled with an electrolyte solution to be injected at a later stage, and the filled electrolyte serves as an ion transfer function. If the pore size and porosity are less than 0.001 袖 m and 10%, respectively, it can act as a resistive layer. If the pore size and porosity exceed 10 袖 m and 90% respectively, the mechanical properties may be deteriorated.

The separation membrane of the present invention may further include other additives as well as the above-mentioned ceramic particles and polymers as the porous coating layer component.

A preferred method of producing the separation membrane according to the present invention is illustrated below, but is not limited thereto.

First, a nonwoven fabric substrate having pores is prepared (step S1).

Next, the ceramic nanoparticles and the ceramic microparticles are simultaneously or sequentially applied to the nonwoven fabric substrate (step S2).

To this end, a mixture of ceramic nanoparticles and ceramic microparticles is added to the binder polymer solution obtained by dissolving the binder polymer in a solvent so as to have a very low solids content to prepare a slurry, which is then coated on the nonwoven substrate.

Alternatively, ceramic nanoparticles and ceramic microparticles may be respectively made into slurries in a binder polymer solution in which a binder polymer is dissolved in a solvent, and the ceramic nanoparticle slurry is coated on the nonwoven fabric substrate. Subsequently, the ceramic microparticles and the ceramic microparticles are sequentially coated with ceramic microparticles The slurry is coated on the nonwoven substrate.

As a result, the ceramic nanoparticles do not enter the large pores of the nonwoven fabric substrate, and the ceramic nanoparticles are incorporated only into the small pores of the nonwoven fabric substrate, so that the content of the lithium-conductive ceramic nanoparticles in the small pores of the nonwoven fabric substrate becomes high.

As the solvent of the binder polymer, it is preferable that the solubility index is similar to that of the binder polymer to be used, and the boiling point is low. This is to facilitate uniform mixing and subsequent solvent removal. Non-limiting examples of usable solvents include acetone, tetrahydrofuran, methylenechloride, chloroform, dimethylformamide, N-methyl-2-pyrrolidone (N -methyl-2-pyrrolidone, NMP), cyclohexane, water or a mixture thereof.

The solution of the binder polymer in which the ceramic particles are dispersed may be coated on the nonwoven fabric substrate by a conventional coating method known in the art. For example, a dip coating, a die coating, a roll coating, , Comma coating, or a combination thereof. In addition, the porous coating layer can be selectively formed on both or only one side of the nonwoven base material. The porous coating layer formed by such a coating method is uniformly formed on the surface of the nonwoven fabric substrate. The ceramic particles in the porous coating layer are connected and fixed to each other by the binder polymer, and the pores are formed due to the interstitial volume between the ceramic particles.

Next, the nonwoven fabric substrate coated with the ceramic nanoparticles and the ceramic microparticles is dried (step S3).

The separator of the present invention is interposed between the positive electrode and the negative electrode to produce a lithium secondary battery. In this case, when a polymer capable of being gelled upon impregnation with a liquid electrolyte is used as the binder polymer component, after the battery is assembled using the separation membrane, the injected electrolyte and the polymer may react with each other to gel.

Non-limiting examples of the lithium secondary battery of the present invention include a lithium metal secondary battery, a lithium ion secondary battery, a lithium polymer secondary battery, or a lithium ion polymer secondary battery.

The electrode to be used together with the separator of the present invention is not particularly limited, and electrode active materials 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. The cathode active material may be a conventional cathode active material that can be used for a cathode of a conventional lithium secondary battery. It is preferable to use a lithium composite oxide. As a non-limiting example of the negative electrode active material, a conventional negative electrode active material that can be used for a negative electrode of a lithium secondary battery 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 are preferable. Non-limiting examples of the positive current collector include aluminum, nickel, or a combination thereof. Examples of the negative current collector include copper, gold, nickel, or a copper alloy or a combination thereof Foil to be manufactured, and the like.

The electrolyte solution that can be used in the lithium secondary battery of the present invention is a salt having a structure such as A ⁺ B ^- , wherein A ⁺ includes an alkali metal cation such as Li ⁺ , Na ⁺ , K ^{+ -} it 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 (DMP), dimethyl sulfoxide, acetonitrile, dimethoxyethane, diethoxyethane, tetrahydrofuran, N-methyl-2-pyrrolidone (NMP), ethylmethyl carbonate (EMC), gamma butyrolactone -Butyrolactone), or a mixture thereof, but the present invention is not limited thereto.

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 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 conventional winding process.

Claims (12)

(a) a nonwoven substrate having pores; And
(b) a porous coating layer located on at least one side of the nonwoven substrate and including ceramic particles and a binder polymer,
Wherein the ceramic particles are connected and fixed to each other by the binder polymer and have pores formed by the interstitial volume between the ceramic particles,
The ceramic particles are composed of ceramic nanoparticles having a small average particle diameter and ceramic microparticles having a large average particle diameter
Membrane for lithium secondary battery.
The method according to claim 1,
Wherein the ceramic nanoparticles have an average particle diameter of 1 to 100 nm.
The method according to claim 1,
Wherein the ceramic microparticles have an average particle diameter of 20 to 100 占 퐉.
The method according to claim 1,
Wherein the pores of the nonwoven fabric have a maximum diameter of 0.1 to 70 탆 and the pore accounts for 50% or more of the total number of nonwoven fabric pores.
The method according to claim 1,
Wherein the ceramic nanoparticles have a dielectric constant of 5 or more.
6. The method of claim 5,
The ceramic nanoparticles are _{BaTiO 3, Pb (Zr, Ti} ) O 3 (PZT), Pb 1 - x La x Zr 1 - y Ti y O 3 (PLZT, where, 0 <x <1, 0 <y <1 _{Lim), Pb (Mg 1/3} Nb 2/3) O 3 -PbTiO 3 (PMN-PT), hafnia (HfO ₂ ), SrTiO ₃ , SnO ₂ , CeO ₂ , MgO, NiO, CaO, ZnO, ZrO ₂ , Y ₂ O ₃ , Al ₂ O ₃ , TiO ₂ , SiC, And the mixture is a mixture.
The method according to claim 1,
Wherein the ceramic microparticle lithium phosphate (Li ₃ PO _4), lithium titanium phosphate _{(LixTiy (PO 4) 3,} 0 <x <2, 0 <y <3), lithium aluminum titanium phosphate (LixAlyTiz (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 0 < y < 1, 0 < z < 1, TiO ₃ , 0 <x <2, 0 <y <3), lithium germanium thiophosphate (Li _x Ge _y P _z S _w , 0 <w <5), lithium nitride (Li _x N _y , 0 <x <4, 0 <y <2), SiS ₂ series glass (Li _x Si _y S _z , <2, characterized in that 0 <z <4), 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 Separator for lithium secondary battery.
The method according to claim 1,
The nonwoven substrate may be formed of a material selected from the group consisting of polyolefins such as polyethylene and polypropylene, polyethylene terephthalate, polyester, polyamide, polyacetal, polycarbonate, polyimide, polyetheretherketone, polyether sulfone, polyphenylene oxide and polyphenylene sulfide , Polyethylene naphthalene, or a mixture thereof.
A lithium secondary battery comprising a negative electrode, a positive electrode, and a separator interposed between the negative electrode and the positive electrode,
The lithium secondary battery according to any one of claims 1 to 8, wherein the separator is a separator for a lithium secondary battery.
Preparing a nonwoven substrate having pores,
Applying ceramic nanoparticles and ceramic microparticles to a nonwoven substrate, and
Drying the nonwoven substrate coated with ceramic nanoparticles and ceramic microparticles
(JP) METHOD FOR PRODUCING A SEPARATE FOR LITHIUM SECONDARY BATTERY
11. The method of claim 10,
Wherein the mixture of the ceramic nanoparticles and the ceramic microparticles is dispersed in a solution in which the binder polymer is dissolved and then applied to the nonwoven fabric substrate.
11. The method of claim 10,
Characterized in that the ceramic nanoparticles are dispersed in a solution of a binder polymer dissolved therein and then applied to a nonwoven fabric substrate and then the ceramic microparticles are dispersed in a solution of a binder polymer dissolved therein and applied to a nonwoven fabric substrate Gt;