KR20180112890A - Separators for Batteries Having Single-layered Coating of Polymeric Particles and Preparation Method Thereof - Google Patents

Abstract

Disclosed are a separator for having a single-layer polymer particle coating layer and a manufacturing method thereof. According to the present invention, a polymer particle having charge is arranged or coated in a single layer on a polymer membrane substrate to provide an effect of suppressing a battery performance degradation phenomenon due to diffusion of charge-retaining species generated by a reaction in a battery (e.g., lithium-sulfur secondary battery).

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a separator for a battery having a single-layer polymer particle coating layer and a method for manufacturing the separator.

The present disclosure relates to a separator for a battery having a single-layer polymer particle coating layer and a method for producing the same. More specifically, the present disclosure relates to a method of forming a polymer membrane, wherein polymer particles having charge on the polymeric membrane substrate are arranged or coated in a single layer to form charge-retaining species (e.g., lithium-sulfur secondary cells) The present invention relates to a separator for a battery which can provide an effect of suppressing the deterioration of battery performance due to diffusion and a novel method for manufacturing the same.

In recent years, demand for portable electronic devices such as smart phones, tablet PCs and notebooks and electric vehicles has increased, and global interest in solving environmental pollution problems such as greenhouse gases caused by the use of fossil energy has led to the development of environment- Is getting popular.

Particularly, an energy storage device having high efficiency, high output, high energy density and light weight characteristics applicable to electronic devices, electric vehicles, and the like with the trend of development of various electronic devices, miniaturization and light weight, and development trends of hybrid vehicles and electric vehicles Is required. As a representative example of such an energy storage device is a secondary battery capable of charging and discharging, a mobile communication, and a portable electronic device, the demand for a secondary battery is gradually increasing, and in particular, Research and development to improve the performance of energy and the like are continuously being carried out.

Among the currently applied rechargeable batteries, the lithium secondary battery developed in the early 1990s has a higher operating voltage and a significantly higher energy density than conventional batteries such as Ni-MH, Ni-Cd and sulfuric acid-lead batteries using an aqueous electrolyte solution , Which accounts for more than 60% of the global rechargeable battery market, and many companies and research institutes are focusing on improving the performance of lithium secondary batteries.

Generally, a lithium secondary battery has a basic configuration in which an electrolyte composed of a lithium salt such as LiPF ₆ dissolved in a non-aqueous organic solvent is filled between a cathode (cathode) and a cathode (anode). The anode is made of lithium-transition metal oxide, and the cathode is made mainly of carbon-based material. Lithium ions move from the anode to the cathode during charging and to the opposite direction during discharge. In addition, in the lithium secondary battery, a separation membrane is disposed between the anode and the cathode so as to prevent direct contact between the anode and the cathode to prevent an internal short-circuit, and to provide a path of lithium ion migration during charging and discharging. In the case of such a separator, generally, (i) a microporous polymer membrane made of a polymer material such as polyethylene or polypropylene, (ii) a nonwoven fabric, and (iii) a ceramic (or ceramic composite material) It is mainstream.

However, lithium secondary batteries commercialized in the past have a risk of ignition / explosion due to the use of organic electrolytic solutions, and lithium secondary batteries have been developed due to the complicated manufacturing process, but there is still a need for technical improvement.

Techniques developed to meet such demands include lithium-sulfur secondary batteries and lithium-air batteries. In particular, a lithium-sulfur secondary battery uses sulfur as a cathode active material and a carbon-based material in which an alkali metal such as lithium or a metal ion such as lithium ion is inserted and removed as a negative electrode active material, Refers to a battery that charges and discharges by the reaction between sulfur and sulfur. In the case of the lithium-sulfur secondary battery, the reduction of the sulfur-sulfur bond during the reduction reaction causes a decrease in the oxidation number of sulfur, and in the oxidation reaction, the oxidation- The reaction is used to store and generate electrical energy.

The lithium-sulfur battery has an energy density of about 3,830 mAh / g when lithium metal is used as an anode active material, and an energy density of about 1675 mAh / g when sulfur (S ₈ ) is used as a cathode active material. , And the electrode material (sulfur used as the cathode active material) is inexpensive and has environment-friendly characteristics. In particular, it has an advantage that it has an energy density of about 4 to 5 times higher than the energy density of a commercial lithium ion battery.

However, when a conventional separation membrane is used as a separator used in a lithium-sulfur secondary battery, the dissolved sulfur reacts with the lithium in the negative electrode during the discharge cycle, so that the lithium electrode is corroded and the resistance depending on the selective ion permeability increases The porous substrate used as a separation membrane may have a long life due to pore clogging.

Particularly, the polysulfide (S _x ) generated at the anode through the reaction between lithium ion and sulfur during the operation of the battery moves to the cathode (anode), thereby reducing the efficiency of the battery as well as the side reaction. (Shuttle phenomenon). In order to alleviate the above-described problems, studies have been made on applying Li to a lithium-sulfur secondary battery by replacing Li with the SO ₃ H ^- group of a PFSA membrane which has been conventionally used in a fuel cell. Recently, A technique for preventing the contact between the polysulfide contained in the electrolytic solution by modifying the surface of the lithium electrode with a polymer having a negative charge has been developed (Korean Patent Publication No. 2015-106253).

In addition, it is also possible to incorporate a negative charge component (or anion group) into the separation membrane (for example, U.S. Patent Nos. 2016-0218342 and 2015-0162586) or a membrane size larger than lithium ion and smaller than a polysulfide ion (For example, U.S. Patent Publication No. 2015-0255769) has also been developed. In this way, in the secondary battery field, the surface characteristics of the separator are modified according to the characteristics of the battery (reaction mechanism, etc.) Or coating techniques have been continuously studied.

Membranes are a key component that directly affects the safety and performance of a battery. Even if they are not involved in a chemical reaction, their structure and characteristics can significantly affect the performance and lifetime of the cell, particularly energy and current density, cycle stability and reliability. do. Particularly, in the next-generation battery system such as a lithium-sulfur secondary battery and a lithium-air battery, the role of the separator is very large.

However, in the prior art related to lithium-sulfur secondary batteries and the like, it is difficult to control the polysulfide still generated depending on the amount of sulfur loaded and it is difficult to surely prove a mechanism of control of diffusion by the repulsive force of negative charge. Therefore, there is a demand for a new membrane production technology capable of improving the lifetime characteristics while increasing the energy density of the battery based on an understanding of the accurate mechanism in the improvement of the separation membrane.

Accordingly, in one embodiment of the present disclosure, there is a need to provide a novel manufacturing method capable of effectively modifying a separation membrane of a secondary battery while differentiating it from an existing system, and a separation membrane applicable to various secondary batteries.

In another embodiment of the present disclosure, there is provided a lithium-sulfur secondary battery having the above-described separation membrane.

According to a first aspect of the present disclosure,

the method comprising: a) providing a polymer particle having a surface charge;

b) arranging the polymer particles in a single layer on a polymer substrate;

c) Separately, forming a binder layer on at least one side of the base membrane structure; And

d) transferring the polymer particles of the single layer arranged on the polymer substrate to the binder layer formed on the base membrane structure through physical bonding, thereby coating the polymer particles with a single layer;

A method for manufacturing a separator for a battery.

According to a second aspect of the present disclosure,

a ') providing a polymer particle having a charge on its surface;

b ') arranging the polymer particles in a single layer on a polymer substrate;

c ') Separately, providing a base membrane structure having at least one surface thereof surface-modified so as to be chemically bondable to the surface of the polymer particles; And

d ') reacting the polymer particles of the single layer arranged on the polymer substrate with the surface-modified base membrane structure to coat the polymer particles having the charge with a single layer through chemical bonding;

A method for manufacturing a separator for a battery.

According to a third aspect of the present disclosure,

Base membrane structure;

A binder layer formed on the base membrane structure; And

A polymer particle coating layer arranged on the binder layer as a single layer and having a surface charge;

/ RTI >

The polymer particle coating layer is attached to the surface of the base membrane structure through physical bonding by a binder layer.

According to a fourth aspect of the present disclosure,

A base membrane structure having at least one surface modified to have a reactive functional group; And

A polymer particle coating layer arranged in a single layer on the surface modified base membrane structure;

/ RTI >

Wherein the surface of the polymer particle has a functional group having a positive charge or a negative charge by ionization,

Wherein the functional groups of the polymer particles react with reactive functional groups on the surface-modified base membrane structure to attach the polymer particles to the surface of the base membrane structure through chemical bonding.

According to a fifth aspect of the present disclosure,

A sulfur-containing anode;

A lithium-containing negative electrode;

The above-described separation membrane disposed between the anode and the cathode; And

A liquid electrolyte filled between the anode and the cathode;

/ RTI >

And the polymer particle coating layer is disposed so as to face the positive electrode.

In one embodiment, the physical coupling may be formed by a stamping method.

In one embodiment, the chemical bond may be formed by esterification of a carboxyl group present on the surface of the polymer particles and a hydroxy group on the surface modified base membrane structure.

According to an exemplary embodiment, the polymer particles may be monodisperse polymer particles.

In an exemplary embodiment, the surface of the polymer particle may have a negatively charged functional group by ionization (or dissociation).

In an exemplary embodiment, the functional group at the negative charge may be a sulfonic acid group, a carboxyl group, a phosphoric acid group, or a combination thereof.

In an exemplary embodiment, the polymeric particles can be of a material selected from the group consisting of polyacrylic acid or copolymers thereof, polymethacrylic acid or copolymers thereof, sulfonated polystyrenes or copolymers thereof, and combinations thereof .

According to an exemplary embodiment, the polymer particles may be solid, hollow, porous, multi-layered or a combination thereof.

In an exemplary embodiment, the material of the binder layer is selected from the group consisting of polyvinyl alcohol, polyacrylamide, casein, gelatin, polyacrylic acid or copolymers thereof, polymethacrylic acid or copolymers thereof, sulfonated polystyrene or copolymers thereof, Poly (3,4-ethylenedioxythiophene), and combinations thereof.

In an exemplary embodiment, the base membrane structure may be a porous polyolefin material.

In an exemplary embodiment, the polymeric substrate may be a rubbery substrate.

In an exemplary embodiment, the polymeric substrate may be selected from the group consisting of polydimethylsiloxane (PDMS), SBS rubber, TPU, NBR, hydrogel, PUA, PVA, PI, PMMA, PVDF, SBR, .

In the exemplary embodiment, a lithium-sulfur secondary battery the electrolyte is _{LiSCN, LiBr, LiI, LiNO 3} , LiPF 6, LiBF 4, LiSbF 6, LiAsF 6, LiCH 3 SO 3, LiCF 3 SO 3, LiClO 4, _{Li (Ph) 4, LiC (} CF 3 SO 2) 3, LiN (CF 3 SO 2) 2, LiN (C 2 F 5 SO 2) 2, LiN (CF 3 CF 2 SO 2) 2, LiAlCl 4, LiB (C ₆ H ₅ ) ₄ , LiCF ₃ SO ₃ , LiN (FSO ₂ ) _2, and mixtures thereof.

The method of manufacturing a separation membrane according to embodiments of the present disclosure suggests a modification method in which polymer particles having a charge on the base membrane structure are coated in a single layer arrangement. As a result, the present invention can be effectively applied to next-generation batteries, particularly lithium-sulfur secondary batteries and lithium-air batteries, which have recently been spotlighted by providing a measure for relatively controlling the energy density in consideration of the mechanism of the battery.

Particularly, according to the present disclosure, the separation membrane having a polymer particle having a negative charge can effectively suppress the diffusion resistance of lithium ions as compared with a film-type coating. In the meantime, A side reaction caused by the reaction of the polysulfide produced in the anode to the cathode, and a problem of deterioration of cell efficiency and lifetime can be solved. Furthermore, since the size or intensity of the negative charge can be controlled according to the ratio of the monomers during the polymerization reaction of the polymer particles, the controllability against the property of the separation membrane is excellent. Therefore, it is expected to greatly contribute to the commercialization of the battery business in the future.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 schematically depicts a series of processes for attaching polymeric particles by physical bonding on a base membrane structure according to one embodiment of the present disclosure;
Figure 2 is a schematic diagram of a series of processes for attaching polymeric particles by chemical bonding on a base membrane structure according to another embodiment of the present disclosure;
FIG. 3 is a graph showing the results of measurement of the concentration of a lithium ion in a lithium-sulfur secondary battery in the case of using a separation membrane in which a polymer particle coating layer having a negative charge is formed in a base membrane structure in the embodiment of the present disclosure and a separation membrane in which a polymer particle coating layer is not formed. Lt; RTI ID = 0.0 > of < / RTI >polysulfide;
4 is a scanning electron micrograph of poly (methacrylic acid-co-ethyleneglycol dimethacrylate) (PME) prepared in Example 1;
5 is a graph showing changes in pH and zeta potential of polymer particles according to the content (by weight) of ethylene glycol dimethacrylate (EGDMA) as a monomer in the production of polymer particles (PME) in Example 1 ;
6 is a scanning electron micrograph of the polymer particles (sulfonated polystyrene) prepared in Example 2;
7 is an optical micrograph (400X) of the surface of the separation membrane in which Polymer (PME) particles are arranged in a single layer on the base membrane structure in Example 3;
8 is an optical micrograph (400X) of the separation membrane surface in which polymer (sulfonated polystyrene) particles are arranged in a single layer on the base membrane structure in Example 5;
FIG. 9 is a graph showing the relationship between the weight ratio of methacrylic acid (MMA) and ethylene glycol dimethacrylate (EGDMA), which are monomers used in Example 1, FIG. 2 is a graph showing changes in battery capacity due to cycle recovery of a sulfur secondary battery; FIG. And
10A to 10C show the first cycle charge / discharge curve of the lithium-sulfur secondary battery fabricated using the separation membrane prepared according to Example 6 to Example 3 and the separation membrane having no polymer particle coating layer, , And battery efficiency up to 60 cycles.

The present invention can be all accomplished by the following description. The following description should be understood to describe preferred embodiments of the present invention, but the present invention is not necessarily limited thereto. It is to be understood that the accompanying drawings are included to provide a further understanding of the invention and are not intended to limit the scope of the invention.

The terms used in this specification can be defined as follows.

&Quot; Polymer " includes both homopolymers and copolymers, and the copolymer can be understood to include random copolymers and block copolymers.

&Quot; Monodisperse " may mean a state or system in which all particles have substantially the same size.

The terms " on " and " on " are used to refer to the relative position concept, and include not only where other elements or layers are directly present in the layer referred to, Elements may be intervening or present.

Similarly, the expressions "under", "under" and "under" and "between" may also be understood as relative concepts of position.

Preparation of Membrane

According to a specific example of this disclosure, polymer particles having a charge (positive charge or negative charge) on the surface, specifically monodisperse polymer particles, are attached (coated) to at least one surface of a base membrane structure constituting the skeleton of the separation membrane as a single layer There is provided a secondary battery separator membrane capable of suppressing the diffusion of charge-retaining species generated by the reaction in the secondary battery, and a method of manufacturing the same.

As an example, the intensity of the charge of the polymer particle (or the surface of the polymer particle) may range, for example, from about 20 to 50 mV, specifically about 30 to 40 mV, more specifically about 32 to 38 mV, The desired level of charge intensity can be selected or adjusted within the above range.

In a specific embodiment, the polymer particle can be a polymer particle having a negative charge, wherein the negative charge may be derived from a functional group having a negative charge such as a sulfonic acid group, a carboxyl group, a phosphoric acid group and the like, ≪ / RTI >

 As the above-mentioned polymer, a polymer having (i) a functional group capable of ionization and having a negative charge, or (ii) a polymer surface-modified to have a negative charge can be exemplified.

(i), specifically, polyacrylic acid or a copolymer thereof, polymethacrylic acid or a copolymer thereof, and the like, and these may be used singly or in combination.

In this connection, when the material of the polymer particle is, for example, a poly (methacrylic acid) polymer (PMMA), it has a functional group having a negative charge as shown in the following general formula (1).

[Formula 1]

Here, n is an integer of 10,000 to 200,000 (specifically 30,000 to 130,000, more specifically 70,000 to 90,000).

(ii), examples of the polymer include polystyrene, specifically styrene, p-methylstyrene, m-methylstyrene, p-ethylstyrene, m-ethylstyrene, The polymer particles obtained by polymerization using monomers in combination can be subjected to an acid treatment to impart a negative charge. Such polystyrene may be understood to include not only styrene homopolymers but also copolymers with acrylonitrile, 1,3-butadiene, divinylbenzene (e.g., 1,3-divinylbenzene).

On the other hand, sulfuric acid, nitric acid, and the like can be exemplified as an acid treatment component that can be used to exhibit a negative charge. For example, sulfonated polymer particles Can be obtained.

[Reaction Scheme 1]

The polymers exemplified above may be prepared by any of the methods known in the art, for example, distillation-precipitation, dispersion polymerization, emulsion polymerization, bulk polymerization, solution polymerization, And seeded polymerization. Particularly, the precipitation-distillation method can produce monodisperse polymer microspheres without additives such as surfactants, and can be produced by using a solvent (a plurality of solvents, specifically, water and acetone Nitrile solvent) can be advantageously controlled in that the size of the produced polymer particles can be controlled.

It is also possible to use polymerization initiators such as benzoyl peroxide, lauryl peroxide, cumene hydroperoxide, methyl ethyl ketone peroxide, t-butyl hydroperoxide, t-butyl peroxy-2-ethyl Peroxide type initiators such as hexanoate, t-hexylperoxy-2-ethylhexanoate and 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate; Azo type initiators such as 2,2'-azobisisobutyronitrile, 2,2'-azobis-2,4-dimethylvaleronitrile and 2,2'-azobis-2-methylisobutyronitrile; Or a combination thereof. The above initiator may be used in an appropriate amount in the range of, for example, about 0.1 to 10 parts by weight, specifically about 0.5 to 1 part by weight, based on 100 parts by weight of the monomer.

In an exemplary embodiment, the polymerization temperature for the production of the polymer particles may be, for example, in the range of about 60 to 90 DEG C, specifically about 70 to 80 DEG C, and as the polymerization reaction progresses, It may be preferable to adjust the polymerization time to an appropriate range. In this regard, an exemplary polymerization reaction time can be in the range of about 30 minutes to 5 hours, specifically about 1 to 3 hours. The reaction conditions described above are exemplary and the present invention is not limited thereto.

According to one embodiment, the polymer particles having a charge may be a copolymer polymerized by using two or more monomers. In this embodiment, it is noted that the diffusion of the charge-retaining species produced by the in-cell reaction can be controlled by controlling the intensity of the charge of the polymer particles according to the ratio between the monomers.

According to an exemplary embodiment, the above-mentioned polymeric monomer can be polymerized using a multifunctional compound (specifically, a crosslinking monomer) as a comonomer. Examples of such comonomers are divinyl benzene, 1,4-divinyloxybutane, divinyl sulfone, diallyl phthalate, diallyl acrylamide, triallyl (iso) cyanurate, triallyl trimellitate, hexanediol di Acrylate, ethylene glycol dimethacrylate, diethylene glycol methacrylate, triethylene glycol dimethacrylate, trimethylene propane trimethacrylate, 1,3-butanediol methacrylate, 1,6-hexanediol dimethacrylate, (Meth) acrylate, pentaerythritol tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol di (meth) acrylate, trimethylol propane, (Meth) acrylate, dipentaerythritol penta (meth) acrylate, glycerol tri (meth) acrylate, allyl (meth) acrylate and the like.

For example, in the case of a copolymer of methacrylic acid and diethylene glycol methacrylate, the charge intensity on the polymer particle surface will decrease as the content of diethylene glycol methacrylate, which is a comonomer, increases. Illustratively, the weight ratio of methacrylic acid: diethylene glycol methacrylate used in the polymerization of the copolymer is, for example, about 4 to 19: 1, specifically about 5 To 9: 1, more specifically about 5.6 to 5.8: 1, and the above-described range can be understood as an example.

According to an exemplary embodiment, the polymer particles having a charge may have a spherical shape, and the average size (diameter) thereof may be, for example, about 200 nm to 6 mu m, specifically about 300 nm to 4 mu m, Specifically about 500 nm to 3 [mu] m.

In addition, the polymer particles having the charge may be solid, hollow, porous, and / or multi-layered. In this connection, in the case of the porous polymer particles, a pore-forming agent can be selectively used to form a porous structure. Examples of such pore-forming agents include toluene, heptane, isooctane, t- amyl alcohol, isoamyl alcohol or Mixtures thereof, more specifically toluene and / or heptane.

On the other hand, the base membrane structure constituting the skeleton of the separation membrane can be a membrane material used as a separation membrane of the secondary battery in the art without any particular limitation. A representative material of such a base membrane structure is a polyolefin, specifically polyethylene, polypropylene or a combination thereof (blend).

Illustratively, the polyethylene may be an ethylene homopolymer or copolymer. Ethylene copolymers may contain, for example, at least 50 mol% of ethylene and at most 50 mol% of one or more comonomers (e.g., alpha -olefins, specifically propylene, butylene, 1-hexene, 1-decene, 1-dodecene, 1-pentene, isobutylene, vinylaromatic compounds such as styrene, (meth) acrylic acid, vinyl acetate, vinyl propionate and / -Alkyl esters)). ≪ / RTI > The polyethylene may be high density polyethylene (HDPE), low density polyethylene (LDPE), or the like.

On the other hand, the polypropylene may be a propylene homopolymer or a copolymer. Propylene copolymers may contain, for example, at least 50 mole percent propylene and up to 50 mole percent of one or more comonomers (e.g., ethylene and / or alpha-olefins (e.g., butylene, 1-hexene, 1-octene, 1-decene, 1-dodecene, and 1-pentene).

The thickness of the base membrane structure is not particularly limited, but may be, for example, in the range of about 10 to 30 mu m, specifically about 15 to 27 mu m, and more specifically about 20 to 25 mu m.

In an exemplary embodiment, the base membrane structure may be comprised of a porous membrane, wherein the pore size is in the range of, for example, about 10 to 64 nm, specifically about 20 to 50 nm, more specifically about 27 to 43 nm And the porosity may also be in the range of at least about 37%, specifically about 40 to 60%, and more specifically about 41 to 55%.

In addition, the BET specific surface area of the base membrane structure may be at least 100 m 2 / g, specifically 200 to 2,000 m 2 / g, more specifically 300 to 1,000 m 2 / g. The physical properties of the above-described base membrane structure are provided for illustrative purposes, and the present invention is not necessarily limited thereto.

In an exemplary embodiment, a commercially available porous membrane may be used as the base membrane structure, and may include a single layer or a plurality of layers (further comprising a polyamide layer, a polycarbonate layer, and / or a porous ceramic layer in addition to the polyolefin layer Lt; / RTI > structure). Examples of such commercial membranes include CELGARD 2400, CELGARD 2500, or CELGARD 2325 commercially available from Celgard, LLC (Charlotte, N.C.).

According to one embodiment, the polymer particles having charge are arranged as a single layer on the base membrane structure of the separator. According to the exemplary embodiment, the amount (coating amount) of the polymer particles coated on the base membrane structure can be determined according to the size of the polymer particles, for example, about 1 to 15 g / m ² , It may be about 2 to 7 g / m ^2, more specifically, about 3 to 5 g / m ² range. For this, the physical bonding (bonding) method and the chemical bonding (chemical reaction) method can be used.

(1) Physical coupling method

The separation membrane according to one embodiment forms a coating layer by arranging polymer particles having charge in the binder layer formed on the base membrane structure as a single layer. Figure 1 schematically shows a series of processes for attaching polymeric particles by physical bonding on a base membrane structure.

In this regard, the material of the binder layer may be selected from the group consisting of polyvinyl alcohol, polyacrylamide, casein, gelatin, polyacrylic acid or copolymers thereof, polymethacrylic acid or copolymers thereof, sulfonated polystyrene or copolymers thereof, 4-ethylenedioxythiophene), and combinations thereof. Further, the thickness of the binder layer may be in the range of, for example, about 0.5 to 1.5 mu m, specifically about 0.8 to 1.2 mu m, more specifically about 0.9 to 1 mu m. Illustratively, the binder layer can be formed by a polymer coating method known in the art, for example, spin coating, cast coating, etc. Especially, the spin coating method may be advantageous.

On the other hand, in this embodiment, the polymer particles having charge are arranged as a single layer on at least one side of the base membrane structure under the interposition of the binder layer. According to an exemplary embodiment, the polymer particles having charge are arranged in a single layer on a separate polymeric substrate, rather than directly on the base membrane structure. According to an exemplary embodiment, the polymer particles can be arranged in a single layer on a polymer substrate by physical methods, specifically rubbing under pressure, pressing (stamping), stamping, and the like. As an example of such a physical arrangement, two polymer bases may be prepared, the polymer particles may be placed on one of the two surfaces, and then the other polymer base material may be arranged as a single layer by pressing and rubbing. At this time, as the polymer base material, for example, a kind having hydrophobicity, adhesiveness and elasticity can be used.

Illustratively, the polymeric substrate may be a rubbery substrate, specifically a polymeric material selected from the group consisting of polydimethylsiloxane (PDMS), SBS rubber, TPU, NBR, hydrogel, PUA, PVA, PI, PMMA, PVDF, SBR, Lt; / RTI > In an exemplary embodiment, the dimension (or thickness) of the polymer base material is not particularly limited as long as the workability is good so that the polymer particles having charge can be easily arranged as a single layer. For example, about 0.1 to 0.5 cm , Specifically about 0.2 to 0.3 cm.

As described above, the polymer particle layer arranged in a single layer on the polymer substrate is brought into contact with the binder layer formed on the base membrane structure, so that the polymer particles have the same pattern as that arranged on the polymer substrate, Layer. In this connection, the polymer particles can be effectively transferred from the polymer base to the binder layer by contacting (or stamping) the binder layer and the polymer particle layer on the polymer base under pressure. At this time, the pressure suitable for the transfer can be adjusted within a range of, for example, at least about 0.1 Pa, specifically about 0.3 to 3 Pa, more specifically about 1 to 1.5 Pa.

(2) Chemical bonding method

In one embodiment, the polymer particles having a charge can form a monolayer coating layer of the polymer particles by chemical bonding with the surface of the base membrane structure, without the interposition of the binder layer, unlike the above-described physical bonding method. Figure 2 schematically shows a series of processes in which polymer particles are attached by chemical bonding on a base membrane structure.

At this time, at least one surface of the base membrane structure is surface-modified to have a reactive functional group, and the reactive functional group formed on the surface is chemically reacted with the positive or negative functional group present on the surface of the polymer particle to be bonded to the surface of the base membrane structure (Fixed). For this purpose, as described above, the polymer particles having a charge are arranged in a single layer on a separate polymer substrate, and then the polymer particles arranged on the polymer substrate and the modified surface of the base membrane structure are brought into contact with each other by chemical reaction Bonds.

In an exemplary embodiment, the chemical bond may be an ester bond between a hydroxy group (-OH) and a carboxy group (COOH). In this case, the surface of the polymer particle is a functional group having a negative charge by ionization, May have a hydroxy group as a reactive functional group.

When a hydrocarbon-based polymer such as polyolefin is used as the base membrane structure, most of its surface will have an inactive C-H. As a surface modification method for converting the C-H bond to C-OH, the initial C-H bond can be converted to C-OH by hydrolysis via an intermediate using the mechanism shown in the following reaction scheme 2 or scheme 3.

[Reaction Scheme 2]

[Reaction Scheme 3]

At this time, a reservoir of an aqueous acid solution (specifically, an aqueous solution of sulfuric acid) is disposed in the esterification reactor (or reaction zone), and is heated to a temperature elevated condition (for example, about 60 to 95 ° C, specifically about 70 to 85 ° C, Lt; RTI ID = 0.0 > 80 C) < / RTI > As described above, the hydroxy group formed by the surface modification of the base membrane structure reacts with the carboxyl group on the surface of the polymer particles, so that the polymer particles having a negative charge can be arranged and adhered to the surface of the base membrane structure as a single layer.

Lithium-sulfur secondary battery

As described above, the separation membrane prepared by forming the coating layer of polymer particles having charge on the base membrane structure can be applied as a separation membrane of a secondary battery. A representative example of such a secondary battery is a lithium-sulfur secondary battery.

Generally, a lithium-sulfur secondary battery comprises: (i) a sulfur-containing anode; (ii) a lithium-containing cathode; (iii) a separator disposed between the anode and the cathode; And (iv) a liquid electrolyte filled between the anode and the cathode. At this time, the cell reaction at the electrodes (anode (cathode) and cathode (anode)) can be expressed as shown in the following reaction formula (4).

[Reaction Scheme 4]

(i) Negative electrode (anode): 2Li → 2Li ⁺ + 2e-

(ii) Positive electrode (cathode): S + 2Li + + 2e-? Li ₂ S

(iii) the total cell reaction _{(discharge): 2Li + S → Li 2} S

In an exemplary embodiment, the anode of the lithium-sulfur secondary cell may comprise a sulfur material having electroactive properties, or a mixture of a sulfur material and a conductive material. Such a mixture forms an electroactive layer, which can be arranged to contact the current collector. Examples of the electroactive sulfur material may include elemental sulfur, a sulfur-based organic compound, a sulfur-based inorganic compound, a sulfur-containing polymer, or a combination thereof. Specifically, S ₈ , Li ₂ S ₈ , Li ₂ S ₆ , Li ₂ S ₄ , Li ₂ S ₂ , or Li ₂ S. More specifically, it may be S ₈ . In addition, the conductive material is not particularly limited, but may include carbonaceous materials such as carbon black, carbon fiber, graphene, and / or carbon nanotubes (CNTs). Illustratively, a sulfur-carbon nanotube composite can be used, and the inner space of the carbon nanotube may be filled with sulfur.

Alternatively, conductive polymers such as polyaniline, polythiophene, polyacetylene, and polypyrrole may be used alone or in combination with the carbonaceous material.

In addition, a binder may optionally be included in the anode. Examples of such binder components include poly (vinyl acetate), polyvinyl alcohol, polyethylene oxide, polyvinyl pyrrolidone, alkylated polyethylene oxide, crosslinked polyethylene oxide , A copolymer of polyvinyl ether, poly (methyl methacrylate), polyvinylidene fluoride, polyhexafluoropropylene and polyvinylidene fluoride (trade name: Kynar), poly (ethyl acrylate), polytetrafluoro Polyvinylpyridine, polystyrene, cellulose, carboxymethylcellulose (CMC), styrene-butadiene rubber (SBR) / carboxymethyl cellulose (CMC), and the like. The content of such a binder may be, for example, about 1 to 20% by weight, specifically about 5 to 15% by weight, based on the total weight of the cathode material.

In an exemplary embodiment, the anode may be formed by applying sulfur particles to porous carbon as a sulfur-carbon composite material. Specifically, the anode may be formed by dissolving sulfur particles and then mixing with carbonaceous components can do. In this case, the weight ratio of sulfur to carbon in the sulfur-carbon composite may be in the range of about 1 to 20: 1, specifically about 3 to 15: 1, more specifically about 5 to 10: 1, It is not.

The electroactive sulfur material or a mixture of the sulfur material and the conductive material is coated or coated on the current collector in the form of a slurry using a solvent (for example, water or an organic solvent such as N-methyl-2-pyrrolidone) . Thereafter, the used solvent may be removed, and the resulting structure may be formed into a composite structure through calendering or the like, and may be cut into a predetermined shape and used as an anode in a battery.

The lithium alloy may be, for example, (i) lithium and (ii) Na, K, Rb, Cs, or a mixture of lithium and lithium. At least one selected from the group consisting of Fe, Be, Mg, Ca, Sr, Ba, Si, Ra, Al, Sn and Ti. Illustratively, a lithium foil can be used as the cathode, wherein the thickness of the lithium foil can range, for example, from about 25 to 200 micrometers, specifically about 50 to 150 micrometers.

In addition, the electrolyte in the lithium-sulfur secondary cell is capable of transferring electric charges between the positive electrode and the negative electrode. For this purpose, a pore formed on the positive electrode and a pore formed on the separation membrane are impregnated. Typically, the electrolyte in the secondary cell may comprise a lithium salt and an organic solvent. By way of example, the lithium salt is _{LiSCN, LiBr, LiI, LiNO 3} , LiPF 6, LiBF 4, LiSbF 6, LiAsF 6, LiCH 3 SO 3, LiCF 3 SO 3, LiClO 4, Li (Ph) 4, LiC (CF _{3 SO 2) 3, LiN (} CF 3 SO 2) 2, LiN (C 2 F 5 SO 2) 2, LiN (CF 3 CF 2 SO 2) 2, LiAlCl 4, LiB (C 6 H 5) 4, LiCF ₃ SO ₃ , LiN (FSO ₂ ) ₂ , and the like, which may be used alone or in combination. At this time, the concentration of the lithium salt may be in the range of, for example, about 0.2 to 4 M, specifically about 0.7 to 3 M, more specifically about 1 to 2 M. The concentration range of the lithium salt is described for illustrative purposes. The concentration range of the lithium salt can be adjusted in consideration of the solubility of the lithium salt in the electrolyte, the ionic conductivity of the dissolved lithium salt, the charge and discharge characteristics of the desired battery, and the operating temperature.

On the other hand, as the organic solvent in the electrolyte, for example, a non-aqueous organic solvent can be used, and examples thereof include bicyclic ethers, cyclic carbonates, sulfoxide compounds, lactone compounds, ketone compounds, ester compounds, A polar compound such as a pyridine compound or a pyridine compound may be used. Specific examples of such an organic solvent include 1,2-dimethoxyethane, 1,2-diethoxyethane, 1,2-dibutoxyethane, dioxolane, 1,4-dioxane, tetrahydrofuran, (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), methyl propyl carbonate (MPC), ethyl propyl carbonate, dipropyl carbonate, butyl ethyl carbonate, ethyl propanoate A solvent such as dimethyl ether (DME), diethyl ether, triethylene glycol monomethyl ether (TEGME), diglyme, tetraglyme, hexamethyl phosphoric triamide, gamma butyrolactone (GBL), acetonitrile, propionitrile, ethylene carbonate (EC), propylene carbonate (PC), N-methylpyrrolidone, 3-methyl-2-oxazolidinone, acetic acid ester, butyl acid ester and propionic acid ester,Methyl formamide, sulfolane, methyl sulfolane, dimethyl acetamide, dimethyl sulfoxide, dimethyl sulfate, ethylene glycol diacetate, dimethyl sulfite, glycol sulfite, and may include a combination thereof. Alternatively, a nonpolar organic solvent such as an aryl compound, specifically, toluene, xylene, or the like may be used as the organic solvent.

In an exemplary embodiment, the coating layer of polymer particles formed on one side of the separator may be oriented (oriented) toward the anode. At this time, the polymer particle coating layer of negative charge formed on the separator prevents the polysulfide (S _x ) generated at the anode from moving to the cathode (anode: Li electrode). As a result, it is possible to alleviate the problem of deterioration in cell efficiency and reduction in service life due to the movement of the polysulfide or the shuttle ring phenomenon.

Referring to FIG. 3, lithium ions (Li ^< ^{+ &} gt ^; ) can move relatively freely through the separator to the anode or the cathode regardless of the polymer particle coating layer having negative charge. On the other hand, when the polysulfide component (for example, Li ₂ S ₄ and / or Li ₂ S ₈ ) migrates to the cathode (Li electrode), the polymer electrolyte membrane . Particularly, as the charge intensity of the polymer particle coating layer is increased, the electrical repulsion phenomenon becomes larger. On the other hand, in the case of a separation membrane in which a coating layer of polymer particles with negative charge is not formed, not only lithium ions (Li ⁺ ) but also polysulfide components pass through the separation membrane and move to the cathode.

It should be noted with respect to this specific example that by introducing a coating layer in which polymer particles are arranged in a single layer, diffusion resistance of lithium ions can be effectively suppressed compared with film-type coating technology, separation membrane surface modification technique, . Particularly, in the case of such a conventional technique, it is difficult to control the polysulfide generated according to the amount of sulfur loaded, and the diffusion control mechanism due to the repulsive force of negative charges can not be clearly realized. This is because the polymer membrane having charge (specifically negative charge) Or the method of confirming the charge on the surface of the modified separation membrane is difficult.

On the other hand, in various embodiments of the present disclosure, the surface charge of the polymer particles in a dispersion (colloid) state before coating can be confirmed by applying a coating layer of polymer particles (in particular monodisperse polymer particles having a uniform size). Furthermore, when the polymer particles are prepared by a copolymerization method, the charge ratio can be controlled by adjusting the ratio between the monomers. In addition, by using a coating layer in which polymer particles (in particular, spherical polymer particles) are arranged in film form rather than a coating layer, the diffusion resistance of lithium ions can be remarkably reduced. In short, the present disclosure can improve the lifetime characteristics of the battery while increasing the energy density of the battery based on the accurate control mechanism of the separation membrane in the secondary battery, particularly the lithium-sulfur secondary battery.

Although a lithium-sulfur secondary battery has been mainly described in the present specification, a technique of coating a polymer particle having a charge in a separation membrane in a secondary battery in a single layer form can be applied to other types of batteries, for example, a lithium-air battery And can be applied to the next generation secondary battery system.

The present invention can be more clearly understood by the following examples, and the following examples are merely illustrative of the present invention and are not intended to limit the scope of the invention.

Example 1

Preparation of Negative Charged Polymer (Poly (MAA / EGDMA)) Particles

Polymerization was carried out by precipitation-distillation using methacrylic acid (MAA; 99%, Sigma-Aldrich) and ethylene glycol dimethacrylate (EGDMA; TCI) as monomers. The total amount of monomer used in the reaction system was 4 g, and the weight ratio of MAA: EGDMA was 1: 1. The polymerization reaction was carried out in a reaction medium consisting of acetonitrile (68 mL), deionized water (12 mL), and 2,2'-azobisisobutyronitrile (AIBN (Junsei); 0.08 g) as an initiator. The polymerization reaction was carried out at 80 DEG C for 40 minutes without stirring. Unreacted monomers and medium were removed by centrifugation. The precipitated particles were washed several times with ethanol and deionized water, and dried for 1 day at room temperature and vacuum to prepare polymer particles of polymethacrylic acid (PMMA) crosslinked with EGDMA Respectively. The polymer particles were spherical in shape and had an average size (particle size) of about 1 mu m.

The polymer particles were put into 300 mL of an aqueous solution of sodium hydroxide (0.001 M) and kept for 2 hours in order to make the carboxylic acid group, which is a functional group present on the polymer particle, to have a negative charge, And the subsequently separated polymer particles were purified by washing with THF. The purified polymer particles were vacuum-dried at room temperature to obtain MMA-EGDMA copolymer particles having a negative charge.

On the other hand, the polymer particles were synthesized by varying the monomer-to-monomer ratio in the production of the copolymer, and the weight ratio, the molar ratio and the particle size are shown in Table 1 below.

A scanning electron microscope (SEM) photograph of the poly (MMA-EDGMA) copolymer (PME) prepared in Example 1 is shown in FIG. As shown in the figure, the polymer particles in the form of microspheres were produced, and it was confirmed that the polymer particles had a very uniform size and a shape close to a tennis ball.

On the other hand, the polymer particles prepared by varying the weight ratio between monomers in the synthesis of polymer particles were added to 30 mL of water to prepare dispersions, and their pH and zeta potentials were measured. The results are shown in Fig.

 According to the figure, even when the amount of EGDMA used as the comonomer increases, the pH increase width is relatively small. As the EGDMA content increased, the zeta potential gradually decreased. That is, as the EGDMA content increases, the charge intensity of the synthesized polymer particles decreases.

Example 2

Preparation of Polymer (Sulfonated Polystyrene) Particles Having Negative Charge

Porous particles of polystyrene-co-divinyl benzene crosslinked with divinylbenzene were synthesized by seed polymerization. Specifically, the sulfonated polystyrene particles were first subjected to dispersion polymerization with physical stirring at 70 DEG C using styrene, an initiator (azobisisobutyronitrile) and polyvinylpyrrolidone to prepare monodispersed polystyrene seed particles , Seed particles were dispersed in a mixed solvent of water and ethanol. Then, a mixed droplet of styrene, divinylbenzene, toluene, and benzoyl peroxide was prepared in a water / alcohol mixed solvent, and the mixture was put into a reactor and polymerized while being physically stirred at 80 ° C. After the internal phase separation, ≪ / RTI > The obtained polymer particles were dried, put into an aqueous solution of sulfuric acid, stirred at 70 DEG C for 12 hours, purified and dried.

10 g of the polystyrene particles synthesized as described above was added to 200 mL of a sulfuric acid solution (1 M), and the mixture was heated for 24 hours and acid-treated at 70 ° C. Thereafter, it was washed several times with ethanol and water and dried to obtain sulfonated polystyrene particles. The physical properties of the thus-prepared sulfonated polystyrene particles are shown in Table 2 below.

An electron micrograph of the sulfonated polystyrene particles is shown in Fig. According to the figure, it can be confirmed that the polymer particles have a slightly rough surface by acid treatment, and that many pores (pores) are formed on the surface, and it is confirmed that the particles are monodispersed through seed polymerization.

Example 3

Preparation of Separation Membrane with Coating Layer of Polymer Particles Having Negative Charge (Physical Bonding)

0.1 g of the polymer particles prepared in Example 1 was placed on a PDMS film (polydimethylsiloxane, product name: Sigma Aldrich Co., Ltd., thickness: 0.3 cm), rubbed with another PDMS film, and arranged in a single layer. Separately, 3 mL of a polyvinyl alcohol (PVA) solution (concentration: 10% by weight) was poured onto a commercially available polymer separator (Celgard 2400; thickness: 25 μm; porosity: 41%; pore size: 43 nm) Speed: 5,000 rpm, holding time: 5 seconds). The thickness of the PVA coating layer was 0.8 탆.

Then, a polymer particle layer arranged as a single layer on the PDMS film was placed in contact with the spin-coated PVA layer on the commercial polymer separation membrane, and maintained at a pressure of 20 g using a weight (stamping method) . Thereafter, the PDMS film was removed, and then a separation membrane coated with a single layer of polymer particles was obtained. As a result, the coating amount of the polymer particles was 3.5 g / m ² . An optical microscope photograph (400 times) of the surface of the thus-prepared coated membrane is shown in Fig. According to the figure, micro-sized poly (MMA-EGDMA) polymer particles having monodispersed characteristics are arranged in a single layer.

Example 4

Preparation of Separation Membrane with Coating Layer of Polymer Particles Having Negative Charge (Chemical Bonding)

The polymer particles used in this example had a carboxyl group, while the surface of the polymer separation membrane was hydroxylated to have a hydroxy group. Specifically, a flat glass plate was introduced into a container having a double wall, a separation membrane (5 × 5 cm) was placed thereon, and a single layer of polymer particles arranged on PDMS (25 μm) was placed so as to face the surface of the glass plate. As shown in Fig. 2, 10 ml of water containing a small amount of an aqueous solution of sulfuric acid (70%, 0.1 ml) was added to the outer part, and the mixture was closed with a flat glass plate and kept at 80 캜 for 3 hours.

Example 5

A separation membrane having a coating layer of polymer particles having a negative charge was prepared in the same manner as in Example 3, except that the polymer (sulfonated polystyrene) particles prepared in Example 2 were used. An optical microscope photograph (400 times) of the prepared separation membrane surface is shown in Fig. From the figure, it can be seen that micro-sized polystyrene polymer particles having monodisperse properties are arranged in a single layer.

Example 6

Performance evaluation of separator in lithium-sulfur battery

A lithium-sulfur secondary battery having the following structure was fabricated, and the performance of the separator prepared in Example 1 was tested.

- cathode

Sulfur (S ₈ ) and carbon nanotubes having multiple layers (multi-layer carbon nanotubes manufactured by Sigma-Aldrich) were mixed at a weight ratio of 7: 3, and sulfur-carbon composites were prepared by vapor deposition. An electrode was prepared by filtering the cathode active material (100 wt%) of the sulfur-carbon composite material and coated on the aluminum current collector to prepare a cathode.

- anode

Lithium foil having a thickness of 120 mu m was used.

- electrolyte

An electrolytic solution in which LiTFSI as a lithium salt was dissolved in DME / DOL at a concentration of 0.5M was used as a solvent.

The lifetime characteristics of the lithium-sulfur secondary battery fabricated using the separator having a single layer of three kinds of polymer particles having different monomer ratios in Example 3 were tested and the results are shown in FIG.

 According to the figure, when the MMA content in the polymer particle was the highest (red), the capacity was decreased at the beginning of the cycle, but the capacity was markedly higher than that of the other polymer particles. On the other hand, when the MMA content was the lowest (green), the battery capacity rapidly decreased with the number of cycles, and remained low.

On the other hand, the lithium-sulfur secondary battery manufactured using the separator prepared in Example 3 (weight ratio of MMA: EGDMA in the polymer particles: 17: 3) and the separator having no coating layer of polymer particles A first cycle charge / discharge curve of the lithium-sulfur secondary battery manufactured using the above-described lithium-sulfur secondary battery, a change in cell capacity up to 60 cycles, and a cell efficiency up to 60 cycles are shown in Figs. 10A to 10C, respectively.

As shown in FIG. 10A, when a separation membrane having a coating layer of polymer particles having a negative charge is formed as in the embodiment, resistance is low as compared with the case where a coating layer of polymer particles is not formed. In addition, referring to FIG. 10B, it can be seen that the case of forming the coating layer of polymer particles shows a stable battery capacity despite the increase in the number of cycles, as compared with the case where the coating layer of polymer particles is formed. Similarly, as can be seen from FIG. 10C, it can be seen that a high level of cell efficiency is maintained by using a separation membrane formed with a coating layer of polymer particles.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (20)

the method comprising: a) providing a polymer particle having a surface charge;
b) arranging the polymer particles in a single layer on a polymer substrate;
c) Separately, forming a binder layer on at least one side of the base membrane structure; And
d) transferring the polymer particles of the single layer arranged on the polymer substrate to the binder layer formed on the base membrane structure through physical bonding, thereby coating the polymer particles with a single layer;
And a separator for separating the battery. a ') providing a polymer particle having a charge on its surface;
b ') arranging the polymer particles in a single layer on a polymer substrate;
c ') Separately, providing a base membrane structure having at least one surface thereof surface-modified so as to be chemically bondable to the surface of the polymer particles; And
d ') reacting the polymer particles of the single layer arranged on the polymer substrate with the surface-modified base membrane structure to coat the polymer particles having the charge with a single layer through chemical bonding;
And a separator for separating the battery. The method of claim 1, wherein the physical connection is formed by a stamping method. The method according to claim 2, wherein the chemical bond is formed by an ester reaction between a carboxyl group present on the surface of the polymer particle and a hydroxy group on the surface modified base membrane structure. The method for manufacturing a separator for a battery according to claim 1 or 2, wherein the polymer particles are monodisperse polymer particles. The method of claim 1 or 2, wherein the surface of the polymer particle has a negative charge group by ionization (or dissociation). The method according to claim 6, wherein the functional group of the negative charge is a sulfonic acid group, a carboxyl group, a phosphoric acid group, or a combination thereof. 3. The method of claim 1 or 2, wherein the polymer particles are selected from the group consisting of polyacrylic acid or copolymers thereof, polymethacrylic acid or copolymers thereof, sulfonated polystyrene or copolymers thereof, Wherein the separator is formed of a metal. The method for producing a separator for a battery according to any one of claims 1 to 5, wherein the polymer particles are solid, hollow, porous, multi-layer, or a combination thereof. The method of claim 1, wherein the material of the binder layer is selected from the group consisting of polyvinyl alcohol, polyacrylamide, casein, gelatin, polyacrylic acid or copolymer thereof, polymethacrylic acid or copolymer thereof, sulfonated polystyrene or copolymer thereof, poly (3,4-ethylenedioxythiophene), and combinations thereof. ≪ / RTI > The method of claim 1 or 2, wherein the base membrane structure is a porous polyolefin material. The polymer base material according to any one of claims 1 to 3, wherein the polymer base material is a rubbery material comprising polydimethylsiloxane (PDMS), SBS rubber, TPU, NBR, hydrogel, PUA, PVA, PI, PMMA, PVDF, SBR and combinations thereof Lt; RTI ID = 0.0 > 1, < / RTI > The polymer particle according to claim 1 or 2, wherein the polymer particle is a copolymer of methacrylic acid and diethylene glycol methacrylate, and the weight ratio of methacrylic acid: diethylene glycol methacrylate used in the polymerization reaction is 5 to 9 : 1. ≪ / RTI > The method of claim 4, wherein the surface-modified base membrane structure has a hydroxyl group on the surface thereof according to the following Reaction Formula 2 or Reaction Formula 3:
[Reaction Scheme 2]

[Reaction Scheme 3]

. Base membrane structure;
A binder layer formed on the base membrane structure; And
A polymer particle coating layer arranged on the binder layer as a single layer and having a surface charge;
/ RTI >
Wherein the polymer particle coating layer is attached to a surface of the base membrane structure through physical bonding by a binder layer. A base membrane structure having at least one surface modified to have a reactive functional group; And
A polymer particle coating layer arranged in a single layer on the surface modified base membrane structure;
/ RTI >
Wherein the surface of the polymer particle has a functional group having a positive charge or a negative charge by ionization,
Wherein the functional groups of the polymer particles react with reactive functional groups on the surface-modified base membrane structure to attach the polymer particles to the surface of the base membrane structure through chemical bonding. 17. The separator for a battery according to claim 15 or 16, wherein an average size of the polymer particles is 200 nm to 6 m. 17. The method of claim 15 or 16, wherein the coating amount of the polymer particles on the base membrane structure is in the range of 3 to 5 g / m < ² >, and the intensity of the charge of the polymer particles is in the range of 32 to 38 mV Battery separator. A sulfur-containing anode;
A lithium-containing negative electrode;
A separation membrane according to claim 15 or 16 disposed between the anode and the cathode; And
A liquid electrolyte filled between the anode and the cathode;
/ RTI >
Wherein the polymer particle coating layer is disposed so as to face the positive electrode. The lithium-sulfur secondary battery according to claim 19, wherein the sulfur-containing cathode is elemental sulfur, a sulfur-containing organic compound, a sulfur-containing inorganic compound, a sulfur-containing polymer or a combination thereof.

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