KR102650356B1 - Separator for a lithium sulfur battery coated with porous composite, manufacturing method thereof, lithium sulfur battery comprising the same - Google Patents

Abstract

One embodiment of the present invention includes a separator; and a porous composite layer located on one or both sides of the separator, wherein the porous composite layer adsorbs polysulfide eluted from the positive electrode of the lithium-sulfur battery to increase battery capacity. It is possible to provide an improved lithium-sulfur battery by preventing reduction and adding the unique properties of the material constituting the porous composite layer.

Description

Separator for lithium-sulfur battery coated with porous composite, manufacturing method thereof, and lithium-sulfur battery comprising the same

The present invention relates to a separator for a lithium-sulfur battery, and more specifically, to a technology for improving the electrochemical performance of a lithium-sulfur battery by coating a porous composite on the separator.

Lithium-sulfur (Li-S) batteries are receiving a lot of attention as one of the next-generation secondary batteries to replace lithium-ion batteries due to their high theoretical capacity and energy density. Additionally, the lithium-sulfur battery system has the advantage of price competitiveness by using non-toxic and abundant sulfur as an active material. Despite these amazing advantages, there are several problems that must be solved for lithium-sulfur batteries to surpass lithium-ion batteries. First, sulfur is electrically insulated, so there is a problem of high cell polarization and low utilization of active materials. Next, polysulfide, an intermediate material, dissolves in the electrolyte and escapes from the anode, resulting in less and less reactable materials. This shuttle effect causes irreversible sulfur loss, resulting in rapid capacity fading and reduced coulombic efficiency of the cell. Therefore, supplementing the electrical properties of sulfur and simultaneously resolving the shuttle effect of sulfide is an essential research required for lithium-sulfur batteries with the various advantages mentioned above to replace lithium-ion batteries.

(Patent) Republic of Korea Patent No. 10-2020-0133317

The problem to be solved by the present invention is to suppress or prevent the shuttle effect, thereby suppressing or preventing the irreversible loss of sulfur, rapid capacity fading, and lowering of the coulombic efficiency of the cell, and further complementing the poor electrochemical properties of sulfur.

To this end, the technical problem to be achieved by the present invention is to provide a separator for a lithium-sulfur battery coated with a porous composite.

Another technical problem to be achieved by the present invention is to provide a method of manufacturing a separator for a lithium-sulfur battery coated with a porous composite.

Another technical problem to be achieved by the present invention is to provide a lithium-sulfur battery including a separator for a lithium-sulfur battery coated with a porous composite.

The technical problem to be achieved by the present invention is not limited to the technical problem mentioned above, and other technical problems not mentioned can be clearly understood by those skilled in the art from the description below. There will be.

In order to achieve the above technical problem, an embodiment of the present invention provides a separator for a lithium-sulfur battery coated with a porous composite.

In an embodiment of the present invention, the separator is a separator; and a porous composite layer located on one or both sides of the separator, wherein the porous composite layer prevents a decrease in battery capacity by adsorbing polysulfide eluted from the positive electrode of a lithium-sulfur battery.

At this time, the porous composite layer is characterized in that two or more types of porous materials of different shapes form a composite.

Additionally, the porous composite layer may have a thickness of 40 μm to 80 μm.

Additionally, the porous material may include a mesoporous material having pores with a size of 2 nm to 50 nm.

Additionally, the porous material may have a specific surface area of 50 m ² /g to 2000 m ² /g.

Additionally, the porous material may include a conductive material.

Additionally, the porous material may contain carbon.

In addition, the porous material may be a separator for a lithium-sulfur battery coated with a porous composite including a spherical shape, a rod shape with regular pores, or a shape with a regular three-dimensional pore structure.

Next, in order to achieve the above technical problem, another embodiment of the present invention provides a method of manufacturing a separator for a lithium-sulfur battery coated with a porous composite.

In an embodiment of the present invention, the method for manufacturing a separator includes preparing a separator and a porous composite; And it may include forming the porous composite on one or both sides of the separator.

At this time, preparing the porous composite includes preparing two or more types of porous materials of different shapes; And it may include a composite step of combining two or more types of porous materials of different shapes prepared above.

Additionally, the step of preparing a porous material having a different shape may include preparing a porous silica matrix when the porous material is carbon; Impregnating the porous silica matrix with a carbon precursor; Carbonizing the porous silica matrix impregnated with the carbon precursor; and removing the porous silica matrix after the carbonization step. It may be a method of manufacturing a separator for a lithium-sulfur battery coated with a porous composite.

Next, in order to achieve the above technical problem, another embodiment of the present invention provides a lithium-sulfur battery including a separator for a lithium-sulfur battery coated with a porous composite.

According to an embodiment of the present invention, a separator; and a porous composite layer located on one or both sides of the separator, wherein the porous composite layer contains highly conductive meso-porous carbon and has a spherical shape, a rod-like shape with regular pores, and a regular three-dimensional pore structure. It is possible to provide a separator for a lithium-sulfur battery coated with a porous composite that combines two or more from the group of porous materials having a shape having regular pores of the normal-type.

The separator, which is an embodiment of the present invention, suppresses or prevents the shuttle effect by adsorbing polysulfide eluted from the anode of a lithium-sulfur battery, and as a result, suppresses the irreversible loss of sulfur, rapid capacity fading, and a decrease in the coulombic efficiency of the cell. In addition, the electrochemical performance of lithium-sulfur batteries can be improved by assisting the electrochemical reaction of sulfur, an active material, including conductive materials.

The effects of the present invention are not limited to the effects described above, and should be understood to include all effects that can be inferred from the configuration of the invention described in the detailed description or claims of the present invention.

Figure 1 is a schematic diagram showing how a porous composite layer is located on one side of a separator.
Figure 2 is a schematic diagram showing the porous composite layer located on both sides of the separator.
Figure 3 is a flow chart of a separator manufacturing method for a lithium-sulfur battery coated with a porous composite, which is an embodiment of the present invention.
Figure 4 is a flowchart of steps for preparing a porous composite in the manufacturing method of an embodiment of the present invention.
Figure 5 is a flowchart of a method of manufacturing a porous material containing carbon and having regular pores in a manufacturing method according to an embodiment of the present invention.
Figure 6(a) is a schematic diagram of the polysulfide shuttle effect occurring in a lithium-sulfur battery.
Figure 6(b) is a schematic diagram of the mechanism by which the separation membrane, which is an embodiment of the present invention, suppresses the shuttle effect.
Figure 7 is a schematic diagram of a method of manufacturing a rod-shaped porous material containing carbon and having regular pores.
Figure 8 shows (a) low-angle XRD, (b) nitrogen adsorption and desorption data, and (c) formed pore size data for a rod-shaped porous material containing carbon and having regular pores.
Figure 9 shows (a) nitrogen adsorption and desorption data and (b) formed pore size data of a porous material containing carbon and having a spherical shape.
Figure 10 is an SEM image and particle size distribution data of a porous material containing carbon and having a spherical shape.
Figure 11 is a cross-section SEM image of a porous composite containing a conventional separation membrane and carbon using a Focused Ion Beam (FIB).
Figure 12 shows electrochemical test data obtained by coating a separator with a porous composite containing carbon and a rod-shaped porous material with regular pores, depending on the coating thickness.
Figure 13 shows Electrochemical Impedance Spectroscopy (EIS) measurement data according to coating thickness after coating a porous composite containing carbon and a rod-shaped porous material with regular pores on a separator.
Figure 14 shows data comparing rate characteristics with existing separators after coating the separator with a porous composite containing carbon and a rod-shaped porous material with regular pores to a thickness of 68 μm.
Figure 15 shows (a) low-angle XRD, (b) nitrogen adsorption and desorption data, and (c) pore size data for a porous material containing carbon and having a regular three-dimensional pore structure.
Figure 16 shows (a) low-angle XRD, (b) nitrogen adsorption and desorption data, and (c) pore size data for a normal type porous material containing carbon and having regular pores.
Figure 17 is an SEM image of a porous composite consisting of a porous material containing carbon and having a regular three-dimensional pore structure and a normal type porous material containing carbon and having regular pores.
Figure 18 shows an existing separator, a separator coated with a porous material containing carbon and having a regular three-dimensional pore structure, a separator coated with a normal type porous material containing carbon and having regular pores, and carbon. This is the electrochemical test data of a separator coated with a porous composite of a porous material with a regular three-dimensional pore structure and a normal type porous material containing carbon and regular pores.

Hereinafter, the present invention will be described with reference to the attached drawings. However, the present invention may be implemented in various different forms and, therefore, is not limited to the embodiments described herein. In order to clearly explain the present invention in the drawings, parts not related to the description are omitted, and similar parts are given similar reference numerals throughout the specification.

Throughout the specification, when a part is said to be "connected (connected, contacted, combined)" with another part, this means not only "directly connected" but also "indirectly connected" with another member in between. "Includes cases where it is. Additionally, when a part "includes" a certain component, this does not mean that other components are excluded, but that other components can be added, unless specifically stated to the contrary.

The terms used herein are only used to describe specific embodiments and are not intended to limit the invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, terms such as “comprise” or “have” are intended to indicate the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, but are not intended to indicate the presence of one or more other features. It should be understood that this does not exclude in advance the possibility of the existence or addition of elements, numbers, steps, operations, components, parts, or combinations thereof.

Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings.

Description will be made with reference to FIGS. 1 and 2. The separator for a lithium-sulfur battery coated with the porous composite of the present invention includes a separator (101); and a porous composite layer 102 located on one or both sides of the separator 101, wherein the porous composite layer 102 prevents a decrease in battery capacity by adsorbing polysulfide eluted from the positive electrode of the lithium-sulfur battery. It is characterized by

First, the separator 101 has insulation properties while allowing lithium ions and electrolyte to pass through, thereby preventing short circuit between the cathode and anode, and is interpreted to mean a separator commonly used in lithium-sulfur batteries, including a polyolefine-based separator. It has to be.

Next, referring to Figures 1 and 2, the separator 101 has a structure in which the porous composite layer 102 is located on one or both sides. As will be seen in the following experimental example, the porous composite layer 102 is formed on one or both sides in consideration of the electrical properties, rate characteristics, and battery thickness required in the environment in which the lithium-sulfur battery containing the separator will be used. Decide whether to form The formation method should be interpreted as being formed according to the method generally used for coating the separator 101.

Next, the porous composite layer 102 will be described with reference to FIG. 6.

The porous composite layer 102 is formed on one or both sides of the separator 101 and serves to prevent a decrease in battery capacity by adsorbing polysulfide eluted from the positive electrode of a lithium-sulfur battery. Depending on the properties of the material constituting the porous composite layer 102, additional properties can be imparted to the lithium-sulfur battery, and when a conductive material is used, it can also serve to compensate for the low electrical conductivity of sulfur, which is the active material.

The thickness of the porous composite layer 102 is preferably 40 μm to 80 μm. If the thickness is less than 40 μm, there is a problem that the degree of improvement in electrochemical properties and increase in capacity according to the coating of the porous composite layer 102 is low, and if the thickness is more than 80 μm, there is a problem that the capacity retention rate decreases.

The porous composite layer 102 is characterized in that two or more types of porous materials of different shapes form a composite.

At this time, the shape of the porous material may include a spherical shape, a rod shape with regular pores, a shape with a regular three-dimensional pore structure, and a normal-type shape. The shape having the regular three-dimensional pore structure refers to a shape in which three-dimensionally interconnected open pores, including the Ia3d mesoporous structure, are arranged in a regular structure, and has significantly excellent pore characteristics such as a large specific surface area. The Normal-type shape refers to a shape manufactured using Normal type-SBA15 silica as a matrix. The manufacturing method is similar to other shapes, including preparing a Normal type-SBA15 silica matrix (S111) and impregnating the silica matrix with a carbon precursor. It is synthesized through a step of carbonizing (S112), a step of carbonizing (S113), and a step of removing the Normal type-SBA15 silica matrix (S114). However, the shape of the porous material is not limited to this and should be interpreted to include various forms that can adsorb a large amount of lithium polysulfide with a large surface area and large pore volume, including ordered mesoporous. .

In addition, two or more types of porous materials having different shapes must be combined.

Additionally, the porous material may include a conductive material, and in this case, the porous material may include carbon.

Specifically, referring to Figures 6(b) and 7(d), in a manufacturing example of a separator for a lithium-sulfur battery coated with a porous composite, which is an embodiment of the present invention, carbon is used to have regular pores. It was synthesized into a rod shape and coated on one or both sides of the separator 101 to form a film, thereby forming pores between the carbon rods synthesized using the carbon. In addition, pores are formed between spherical carbon particles even when carbon is synthesized into a spherical shape, and similarly, pores are formed even when the rod-shaped carbon having regular pores and spherical carbon particles are synthesized in combination, which allows for various types of carbon particles. It can be expected that pores of any size and shape can be formed.

As will be seen in Experimental Example 4 below, when the porous composite layer 102 is formed by combining two or more types of porous materials having different shapes, the porous composite layer 102 is formed with a porous material having a single shape. It is more effective in suppressing the decrease in battery capacity than in the case of this case. Therefore, when the porous composite layer 102 is formed by combining two or more types of porous materials with different shapes, the same battery capacity reduction effect as when using a porous material with a single shape at a thinner thickness can be obtained, and at the same time, This results in reducing the decrease in mobility of lithium ions due to additional coating of material on the separator 101 and reducing the decrease in electrical conductivity of the lithium-sulfur battery. Looking at the reason, the adsorption of lithium polysulfide eluted from the positive electrode during charging and discharging is due to pores inside and on the surface of the porous material itself or pores formed by accumulation of the porous material. Therefore, the porous composite layer 102 formed by combining two or more types of porous materials with different shapes has a lower average porosity compared to the case where it is formed with a porous material having a single shape. Since the porosity is low, the amount and frequency of lithium polysulfide adsorbed into the pores formed when the porous material accumulates are high. As a result, the battery capacity reduction effect caused by the shuttle effect can be suppressed more effectively. Additionally, when the porous composite layer 102 formed by combining two or more types of porous materials having different shapes includes a conductive material, the frequency of contact with the conductive material increases due to the relatively small average porosity and the electrical conductivity decreases. It is expected that the electrical properties of the porous composite layer 102 will increase.

Additionally, the porous material may include a mesoporous material having pores with a size of 2 nm to 50 nm.

To explain the size of the pore in detail, the size of the pore is determined considering the purpose of preventing the polysulfide shuttle effect and the purpose of allowing lithium ions and electrolyte to move as a basic mechanism of a lithium secondary battery. Based on this, The pore size of the porous material is preferably 2 nm to 50 nm. According to claim 2, or in the same context, it is preferable that the specific surface area of the porous material is 50 m ² /g to 2000 m ² /g.

Next, if the material is described in detail, the pores can physically prevent the polysulfide shuttle effect and provide properties to the lithium-sulfur battery through the properties of the material constituting the porous composite layer 102. Sulfur, which is an active material in lithium-sulfur batteries, has the disadvantage of having low electrical conductivity as an active material by itself, so it is desirable to implement the porous composite layer 102 with a conductive material to compensate for this, and the present invention is an example of this. In one preparation example, carbon was used as the porous material. However, it is not limited to this, and any material that is a conductive material or has properties intended to improve lithium-sulfur batteries should be construed as being included in the scope of the present invention.

Next, a method of manufacturing a separator for a lithium-sulfur battery coated with a porous composite, which is an embodiment of the present invention, will be described with reference to FIGS. 3 to 5 and FIG. 7.

The manufacturing method according to an embodiment of the present invention includes preparing a separator 101 and a porous composite 102 (S100); and forming the porous composite 102 on one or both sides of the separator 101 (S200).

Excluding the content that overlaps with the content described in the separator for a lithium-sulfur battery coated with the porous composite 102, the step (S100) of preparing the porous composite 102 involves forming two or more types of porosity of different shapes. Preparing a material (S110); And it may include a combining step (S120) of combining the two or more types of porous materials of different shapes. In this case, the combining method involves preparing the porous materials of different shapes and sequentially combining them on one or both sides of the separator 101. or preparing and mixing porous materials of different shapes and then forming the mixed composite 102 on one or both sides of the separator 101. The method of synthesizing the porous materials with different shapes differs depending on the target material and the method of forming them on the separator 101 varies, and methods that can be generally used by those skilled in the art of the present invention It should be interpreted as including.

To describe the material specifically, one manufacturing example embodying the present invention used carbon as the porous material. When explaining this with reference to FIG. 7, the step of preparing a porous material having a different shape (S110) includes preparing a porous silica matrix when the porous material is carbon (S111); Impregnating the porous silica matrix with a carbon precursor (S112); Carbonizing the porous silica matrix impregnated with the carbon precursor (S113); And it may include a step of removing the porous silica matrix after the carbonization step (S114). The porous composite containing carbon prepared according to the above manufacturing method has a large surface area and a large pore volume, so it can adsorb a large amount of lithium polysulfide and has thermally and chemically stable properties.

Next, an embodiment of the present invention discloses a lithium-sulfur battery including a separator for a lithium-sulfur battery coated with the porous composite 102. As described above, when the separator is included, the polysulfide shuttle effect of the lithium-sulfur battery is suppressed, thereby preventing a decrease in battery capacity, and additional properties are provided depending on the unique properties of the material constituting the porous composite 102. An added lithium-sulfur battery can be provided.

Manufacturing Example 1

Method for producing a rod-shaped porous material containing carbon

Referring to Figure 7, a rod-type porous composite layer 102 with uniform pores was synthesized through the hard template method. After synthesizing the material, in order to coat the separator 101, a rod-type porous composite layer 102 with a smaller and more uniform particle size was synthesized into a porous composite layer 102 containing carbon using silica as a template.

As a carbon precursor, phenanthrene was used and impregnated using the incipient wetness method, carbonized at 900°C, and then silica was removed with hydrofluoric acid to obtain a porous composite layer (102) containing rod-type carbon.

Experimental Example 1

Measurement of properties of rod-shaped porous materials containing carbon and having regular pores

Referring to Figure 8, Figure 8 shows (a) low-angle XRD, (b) nitrogen adsorption and desorption data, and (c) formed pore size data of a rod-shaped porous material containing carbon and having regular pores.

According to Figure 8(a), it can be confirmed through low-angle XRD data that a 2D hexagonal structure with regular pores is well formed.

In addition, according to Figure 8(b), a type 4 hysteresis loop can be seen in the nitrogen adsorption and desorption results, and it can be seen that mesopores with a large surface area are well formed.

In addition, according to Figure 8(c), it was confirmed to have mesopores of about 4 nm in size through the pore distribution graph obtained through the Barrett-Joyner-Halenda (BJH) method.

Experimental Example 2

Measurement of properties of porous materials containing carbon and having a spherical shape

Figure 9 shows nitrogen adsorption/desorption data and formed pore size data of a porous material containing carbon and having a spherical shape.

Figure 10 is an SEM image of a porous material containing carbon and having a spherical shape.

Uniform spherical mesoporous carbon was synthesized. According to Figure 9(a), a type 4 hysteresis loop can be seen through nitrogen adsorption and desorption data, and it can be confirmed that mesopores with a large surface area are well formed.

In addition, according to Figure 9(b), it was confirmed that the mesopore size was about 12 nm through the pore distribution graph.

In addition, referring to Figure 10, it was confirmed through the SEM image that a sphere shape of about 1600 nm in size was well formed.

Experimental Example 3

A porous composite containing carbon and a rod-shaped porous material with regular pores is coated on the separator 101, and properties are measured according to the coating thickness.

When explained with reference to Figures 11 to 15,

Figure 11 is a cross-section SEM image of a porous composite containing a conventional separator 101 and carbon using a Focused Ion Beam (FIB).

Figure 12 shows electrochemical test data obtained by coating the separator 101 with a porous composite containing carbon and a rod-shaped porous material with regular pores, according to the coating thickness.

Figure 13 shows Electrochemical Impedance Spectroscopy (EIS) measurement data according to the coating thickness after coating the separator 101 with a porous composite containing carbon and a rod-shaped porous material with regular pores.

Figure 14 shows data comparing rate characteristics with the existing separator 101 after coating the separator 101 with a porous composite containing carbon and a rod-shaped porous material with regular pores to a thickness of 68 μm.

Referring to Figure 11, the porous composite was synthesized and then coated on the separator 101. Afterwards, a cross-sectional SEM image was obtained through Focused Ion Beam (FIB) to confirm the thickness of the porous composite layer 102 coated. The cross-section of the existing separator (101), Celgard 2400, and the porous composite layer (102) containing carbon were confirmed to have a thickness of 32, 68, and 86 μm, respectively.

Referring to FIG. 12, as a result of electrochemical testing by applying each separator to a battery, it was confirmed that the electrochemical performance was improved compared to when using the existing separator 101 (Celgard 2400). Compared to the existing separator 101, the initial capacity increased as the thickness of the porous composite layer 102 containing carbon increased. In addition, the separator coated with a thickness of 68 μm maintained high capacity up to 300 cycles and showed excellent electrochemical performance.

Referring to Figure 13, electrochemical impedance spectroscopy (EIS) was measured to measure the resistance of the battery. The EIS of the battery was measured before and after 300 cycles. In the case of a separator coated with a porous composite layer 102 containing carbon, it can be confirmed that the resistance is very small, which means that the carbon of the porous composite layer 102 containing carbon has high conductivity and This is thought to be because the porous composite layer 102 acts as another current collector.

Coating the porous composite layer 102 containing carbon can reduce the resistance of the battery and help sulfur, an active material with low conductivity, sufficiently react to participate in the electrochemical reaction. In addition, when looking at the EIS data of the battery after 300 cycles, it was confirmed that the resistance increased when the existing separator 101 was used, but the resistance value was lower when the separator coated with the porous composite layer 102 containing carbon was used. You can.

Referring to Figure 14, it was also confirmed that excellent rate characteristics were shown when a separator coated with a porous composite layer 102 containing carbon with good conductivity was used. As a result of measuring the rate characteristic data of the existing separator (101) and a separator coated with carbon at 68 μm, the capacity of the existing separator (101) drops sharply as the rate increases, and the capacity is not developed at 5 C-rate. It can be seen that the separator coated with the porous composite layer 102 containing carbon maintains its capacity better even at high rates and recovers well even when turned back to 0.1 C-rate.

Experimental Example 4

Measurement of properties of a separator coated with a porous composite consisting of a porous material containing carbon and having a regular three-dimensional pore structure and a normal type porous material containing carbon and having regular pores.

Figure 15 shows (a) low-angle XRD, (b) nitrogen adsorption and desorption data, and (c) pore size data for a porous material containing carbon and having a regular three-dimensional pore structure.

Figure 16 shows (a) low-angle XRD, (b) nitrogen adsorption and desorption data, and (c) pore size data for a normal type porous material containing carbon and having regular pores.

Figure 17 is an SEM image of a porous composite consisting of a porous material containing carbon and having a regular three-dimensional pore structure and a normal type porous material containing carbon and having regular pores.

Figure 18 shows the existing separator 101, a separator coated with a porous material containing carbon and having a regular three-dimensional pore structure, a separator coated with a normal type porous material containing carbon and having regular pores, and This is electrochemical test data of a separator coated with a porous composite of a porous material containing carbon and having a regular three-dimensional pore structure and a normal type porous material containing carbon and having regular pores.

According to Figure 15(a), it can be confirmed through low-angle XRD data that the Ia3d mesoporous structure with a regular three-dimensional pore structure is well formed.

In addition, according to Figure 15(b), a type 4 hysteresis loop can be seen in the nitrogen adsorption and desorption results, and it can be seen that mesopores with a large surface area are well formed.

In addition, according to Figure 15(c), it was confirmed to have mesopores of about 4 nm in size through the pore distribution graph obtained through the Barrett-Joyner-Halenda (BJH) method.

According to Figure 16(a), it can be confirmed through low-angle XRD data that a normal-type structure with regular pores is well formed.

In addition, according to Figure 16(b), a type 4 hysteresis loop can be seen in the nitrogen adsorption and desorption results, and it can be seen that mesopores with a large surface area are well formed.

In addition, according to Figure 16(c), it was confirmed to have mesopores of about 4 nm in size through the pore distribution graph obtained through the Barrett-Joyner-Halenda (BJH) method.

According to Figure 17, it can be seen that a porous material of the Ia3d mesoporous structure containing carbon and having regular three-dimensional pores and a porous material of the normal type having regular pores containing carbon are entangled and coated with each other. You can see pores of various sizes and shapes formed by porous materials with different shapes stacking on each other. In addition, the porous material of the Ia3d mesoporous structure with regular three-dimensional pores is filled between the normal type porous materials, showing that the porous composite formed by combining two or more types of porous materials with different shapes has a single-shaped porosity. Compared to a porous composite formed from a material, it can be expected that the porosity is low, and this can be expected to result in a relatively large amount of lithium polysulfide adsorption, a high adsorption frequency, and further improvement in the effect of reducing battery capacity due to the shuttle effect. .

According to Figure 18, compared to a porous composite formed by combining two or more types of porous materials with different shapes, the effect of improving the electric capacity reduction phenomenon is significant even with repeated charging and discharging when compared to a porous composite formed by a single-shaped porous material. could be confirmed numerically.

The description of the present invention described above is for illustrative purposes, and those skilled in the art will understand that the present invention can be easily modified into other specific forms without changing the technical idea or essential features of the present invention. will be. Therefore, the embodiments described above should be understood in all respects as illustrative and not restrictive. For example, each component described as single may be implemented in a distributed manner, and similarly, components described as distributed may also be implemented in a combined form.

The scope of the present invention is indicated by the patent claims described below, and all changes or modified forms derived from the meaning and scope of the claims and their equivalent concepts should be construed as being included in the scope of the present invention.

101: Separator
102: Porous composite layer

Claims (12)

separation membrane; and
It includes a porous composite layer located on one or both sides of the separator.
The porous composite layer is formed by combining two or more mesoporous materials of different shapes, and prevents a decrease in battery capacity by adsorbing polysulfite eluted from the positive electrode of a lithium-sulfur battery. Separator for batteries. According to paragraph 1,
A separator for a lithium-sulfur battery, wherein the mesoporous material is mesoporous carbon. According to paragraph 1,
A separator for a lithium-sulfur battery coated with a porous composite, characterized in that the thickness of the porous composite layer is 40 μm to 80 μm. According to paragraph 1,
A separator for a lithium-sulfur battery coated with a porous composite, wherein the mesoporous material has pores with a size of 2 nm to 50 nm. According to paragraph 1,
A separator for a lithium-sulfur battery coated with a porous composite, characterized in that the specific surface area of the mesoporous material is 50 m ² /g to 2000 m ² /g. According to paragraph 1,
A separator for a lithium-sulfur battery coated with a porous composite, wherein the mesoporous material includes a conductive material. According to paragraph 1,
The mesoporous material is a separator for a lithium-sulfur battery coated with a porous composite, characterized in that the mesoporous material includes a plurality of spherical or rod-shaped materials, and the materials are stacked in complex with each other to form pores. delete According to paragraph 1,
A method of manufacturing a separator for a lithium-sulfur battery coated with a porous composite, wherein the mesoporous material is manufactured using a porous silica matrix. Preparing two or more mesoporous materials with different shapes; and
A method of manufacturing a separator for a lithium-sulfur battery coated with a porous composite, comprising a composite step of combining two or more of the prepared mesoporous materials of different shapes. According to clause 10,
The step of preparing two or more mesoporous materials having different shapes includes preparing a porous silica matrix when the porous material is carbon;
Impregnating the porous silica matrix with a carbon precursor;
Carbonizing the porous silica matrix impregnated with the carbon precursor; and
A method of manufacturing a separator for a lithium-sulfur battery coated with a porous composite, comprising the step of removing the porous silica matrix. A lithium-sulfur battery comprising a separator for a lithium-sulfur battery coated with the porous composite according to claim 1.

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