KR102448073B1 - Porous polymer membrane coated oxide semiconductor, lithium-sulfur battery including the same as a negative electrode and method for preparing lithium-sulfur battery - Google Patents

Abstract

Disclosed are a porous polymer membrane coated with an oxide semiconductor capable of improving the lithium anode performance of a lithium-sulfur battery by coating an oxide semiconductor on the surface of the porous polymer membrane, a lithium-sulfur battery including the same as an anode, and a manufacturing method thereof. The oxide semiconductor-coated porous polymer film is applied as an anode structure of a lithium-sulfur battery and bonded to lithium metal, the polymer film having pores; and an oxide semiconductor layer formed on the surface of the polymer film.

Description

A porous polymer film coated with an oxide semiconductor, a lithium-sulfur battery including the same as a negative electrode, and a method for manufacturing the same

The present invention relates to a porous polymer membrane applied as a negative electrode structure of a lithium-sulfur battery, and more particularly, an oxide capable of improving the lithium negative electrode performance of a lithium-sulfur battery by coating an oxide semiconductor on the surface of the porous polymer membrane It relates to a porous polymer film coated with a semiconductor, a lithium-sulfur battery including the same as an anode, and a method for manufacturing the same.

As interest in energy storage technology increases, the field of application expands to energy of mobile phones, tablets, laptops and camcorders, and even electric vehicles (EVs) and hybrid electric vehicles (HEVs). Research and development of chemical devices is gradually increasing. Electrochemical devices are the field receiving the most attention in this aspect, and among them, the development of secondary batteries such as lithium-sulfur batteries capable of charging/discharging is the focus of interest, and in recent years, capacity density in developing such batteries And in order to improve specific energy, it leads to research and development for design of new electrodes and batteries.

Such an electrochemical device, among them, a lithium-sulfur battery, has a high energy density and is in the spotlight as a next-generation secondary battery that can replace a lithium ion battery, and accordingly, the importance of a lithium negative electrode is also increasing. The positive electrode of the lithium-sulfur battery does not contain lithium ions, so lithium metal is used as the negative electrode material. Lithium metal has a very light density of 0.53 g/cm ³ , which is advantageous in terms of energy density of the battery, and is the most It has a low standard redox potential, so it is very advantageous as an anode material for batteries. However, since lithium has a very high reactivity with moisture and oxygen, and there is a possibility that a short circuit of the battery may occur due to the formation of dendrites, the lithium-sulfur battery is applied to a large-capacity secondary battery such as an electric vehicle. In order to do this, it is necessary to solve the problem of lowering the safety of lithium.

In this regard, various research results have been reported that can inhibit the growth of lithium dendrites, such as the introduction of a high-strength protective film and the development of an electrolyte additive for solid electrolyte interface (SEI) stabilization. A lot of research using matrix) structures is in progress. When the matrix is applied as an anode structure, it provides a host where lithium plating/stripping occurs, thereby not only mitigating the change in volume that occurs during charging/discharging, but also reducing the distribution of lithium ions. Since it has advantages such as leveling, it is expected that the growth of lithium dendrites can be fundamentally suppressed. Therefore, the development of a method capable of using the lithium anode matrix structure but actually commercializing it is required.

Accordingly, an object of the present invention is to improve the lithium anode performance of a lithium-sulfur battery by coating an oxide semiconductor on the surface of the porous polymer film and then applying it as an anode structure, an oxide semiconductor-coated porous polymer film, this To provide a lithium-sulfur battery including an anode and a method for manufacturing the same.

In order to achieve the above object, the present invention is applied as an anode structure of a lithium-sulfur battery and bonded to lithium metal, comprising: a polymer film having pores; and an oxide semiconductor layer formed on the surface of the polymer film.

In addition, the present invention, the positive electrode; a negative electrode comprising a porous polymer film coated with lithium metal and an oxide semiconductor bonded to the lithium metal; an electrolyte interposed between the positive electrode and the negative electrode; and a separator; and a lithium-sulfur battery comprising a.

In addition, the present invention, a) dispersing the oxide semiconductor in a solvent to prepare an oxide semiconductor solution; b) coating the prepared oxide semiconductor solution on the surface of the non-conductive and porous polymer film, drying and heat treatment to prepare an oxide semiconductor coating polymer film; c) preparing an anode by bonding lithium metal to the prepared oxide semiconductor-coated polymer film; and d) installing a positive electrode to face the negative electrode, and then installing an electrolyte and a separator between the negative electrode and the positive electrode.

According to the porous polymer film coated with an oxide semiconductor according to the present invention, a lithium-sulfur battery comprising the same as an anode, and a manufacturing method thereof, the oxide semiconductor-coated porous polymer film is applied as an anode structure to suppress the growth of lithium dendrites. , there is an advantage in that the anode performance of the lithium-sulfur battery is improved, such as improving the capacity and lifespan characteristics of the battery.

1 is an image of an oxide semiconductor-coated polymer film observed with a scanning electron microscope (SEM) according to an embodiment of the present invention.
2 is an image of a polyimide radiation film in a bare state according to a comparative example observed with a scanning electron microscope.
3 is a graph comparing and contrasting the lifespan characteristics of lithium-sulfur batteries according to an embodiment and a comparative example of the present invention.
4 is a graph comparing and contrasting the discharge capacities of lithium-sulfur batteries according to an embodiment and a comparative example of the present invention.

Hereinafter, the present invention will be described in detail.

The oxide semiconductor-coated porous polymer film according to the present invention is applied as a negative electrode structure of a lithium-sulfur battery and bonded to lithium metal, and includes a polymer film having pores and an oxide semiconductor layer formed on the surface of the polymer film. .

First, the polymer membrane has non-conductive and porous properties, and a membrane made of a polymer having such properties can be used without any particular limitation, and a polymer radiation membrane formed by spinning a polymer by various spinning methods such as electrospinning, etc. can be exemplified. Here, when using the radiation film exemplified above, there may be an advantage in using it compared to a polymer film formed by other methods. The kind of polymer forming the polymer film may be used without particular limitation as long as it is a material capable of forming a porous polymer structure, such as polyimide (PI), and therefore, more specific examples of the polymer film include a PI radiation film and Those having similar properties can be mentioned.

The porosity of the pores formed in the polymer film is preferably set as high as 70 to 95%, preferably 80 to 90%, in order to minimize the increase in energy density of the lithium-sulfur battery. In addition, the thickness of the polymer film (with the exception of the oxide semiconductor or in the bare state) is 1 to 100 µm, preferably 5 to 50 µm, more preferably 10 to 20 µm, and the thickness of the polymer film is 100 µm When it exceeds 1 μm, there is a risk that the polymer film acts as a resistive layer and deteriorates cell performance. There may be problems that cannot be

In addition, in order to prevent the polymer film from being damaged during the heat treatment process in which the oxide semiconductor is coated on the surface (without the oxide semiconductor, or in the bare state), the polymer film is 200 ° C. or higher, preferably 200 to 500 ° C., more Preferably, it is good to have a heat resistance temperature of 250 to 300 °C. When the heat resistance temperature of the polymer film is less than 200° C., it has relatively low heat resistance, and thus a problem in that the polymer film is damaged during heat treatment may occur.

Next, an oxide semiconductor layer formed by coating on the surface of the polymer film will be described. The oxide semiconductor constituting the oxide semiconductor layer is a compound having a semiconductor property consisting of an ionic bond between a metal cation and an oxygen anion, and when it is coated on the polymer film and applied as a negative electrode structure of a lithium-sulfur battery, It has excellent affinity with lithium metal used as an anode, so that alloying reaction with lithium metal is possible, and lithium can be used without limitation as long as it allows good growth of lithium in the polymer film structure.

Examples of the oxide semiconductor include ZnO, SnO ₂ , In ₂ O ₃ and Ga ₂ O ₃ , and the use of ZnO is most suitable for the present invention. In addition, the oxide semiconductor may be formed (or coated) on the polymer film to a thickness of 10 to 500 nm, preferably 100 to 400 nm, more preferably 200 to 300 nm, in this case, the oxide semiconductor If the thickness is less than 10 nm, a problem may occur that the surface of the polymer does not secure sufficient lithium affinity, and if it exceeds 500 nm, an oxide semiconductor exists more than necessary and a problem of continuous reaction with lithium may occur. .

The porosity of the oxide semiconductor-coated porous polymer film according to the present invention having the above configuration is 70 to 95%, preferably 80 to 90%, which is the same as or similar to the polymer film before the oxide semiconductor is coated. The porosity is shown. From this, it can be seen that the properties of the basic polymer film are maintained even when the oxide semiconductor is coated.

Next, a lithium-sulfur battery including a porous polymer film coated with an oxide semiconductor as an anode according to the present invention will be described. The lithium-sulfur battery includes a positive electrode, a negative electrode including a lithium metal and a porous polymer film coated with an oxide semiconductor bonded to the lithium metal, an electrolyte and a separator interposed between the positive electrode and the negative electrode. The general configuration of the positive electrode and the negative electrode, the electrolyte, and the separator may be conventional ones used in the art, and a detailed description thereof will be provided later.

Meanwhile, according to the present invention, it is also possible to provide a battery module including the lithium-sulfur battery as a unit cell and a battery pack including the same. The battery module or battery pack is a power tool (Power tool); electric vehicles, including electric vehicles (EVs), hybrid electric vehicles, and plug-in hybrid electric vehicles (PHEVs); or systems for power storage; Any one or more of them may be used as a power supply for medium or large devices.

Finally, a method for manufacturing a lithium-sulfur battery including a porous polymer film coated with an oxide semiconductor as an anode according to the present invention will be described. The manufacturing method of the lithium-sulfur battery comprises the steps of: a) dispersing an oxide semiconductor in a solvent to prepare an oxide semiconductor solution, b) coating the prepared oxide semiconductor solution on the surface of a non-conductive and porous polymer film, then drying and Heat treatment to prepare an oxide semiconductor-coated polymer film, c) bonding lithium metal to the prepared oxide semiconductor-coated polymer film to prepare a negative electrode, and d) after installing the positive electrode to face the negative electrode, the negative electrode and installing an electrolyte and a separator between the anode and the anode.

As the solvent used in step a), any solvent capable of dispersing the oxide semiconductor, such as 2-ethanolamine, 2-ethoxyethanol, and those having properties similar to these, may be used without particular limitation. The coating process of step b) may be performed by a method capable of coating the oxide semiconductor on the surface of the polymer film, such as a supporting method and a spraying method. When the coating process is performed by a supporting method, the polymer film should be supported in the oxide semiconductor solution for 10 to 600 seconds, preferably 60 to 120 seconds. In addition, the drying in step b) may be carried out under an air atmosphere for 30 minutes to 3 hours, preferably 1 to 2 hours, at a temperature of 100 to 300 °C, preferably 200 to 250 °C.

In addition, the description of the oxide semiconductor and the polymer film is applied mutatis mutandis, and the general configuration of the anode and the cathode, the electrolyte and the separator may be conventional ones used in the art.

Hereinafter, a description of the positive electrode, the electrolyte and the separator applied to the lithium-sulfur battery including the oxide semiconductor-coated porous polymer film according to the present invention as the negative electrode will be added.

anode

With respect to the positive electrode used in the present invention, after preparing a positive electrode composition including a positive electrode active material, a conductive material and a binder, the slurry prepared by diluting it in a predetermined solvent (dispersion medium) is directly coated on the positive electrode current collector and By drying, the positive electrode layer can be formed. Alternatively, after casting the slurry on a separate support, a film obtained by peeling from the support may be laminated on a positive electrode current collector to prepare a positive electrode layer. In addition, the positive electrode may be manufactured in various ways using methods well known to those skilled in the art.

The conducting material serves as a path through which electrons move from the positive electrode current collector to the positive electrode active material, and not only provides electronic conductivity, but also electrically connects the electrolyte and the positive electrode active material, so that lithium ions (Li+) in the electrolyte It serves as a pathway to move to sulfur and react. Therefore, if the amount of the conductive material is not sufficient or does not perform its role properly, the non-reactive portion of sulfur in the electrode increases, which eventually causes a decrease in capacity. In addition, since it adversely affects the high-rate discharge characteristics and the charge/discharge cycle life, it is necessary to add an appropriate conductive material. The content of the conductive material is preferably added appropriately within the range of 0.01 to 30% by weight based on the total weight of the positive electrode composition.

The conductive material is not particularly limited as long as it has conductivity without causing a chemical change in the battery, for example, graphite; carbon black such as Denka Black, Acetylene Black, Ketjen Black, Channel Black, Furnace Black, Lamp Black and Summer Black; conductive fibers such as carbon fibers and metal fibers; metal powders such as carbon fluoride, aluminum and nickel powder; conductive whiskers such as zinc oxide and potassium titanate; conductive metal oxides such as titanium oxide; Conductive materials such as polyphenylene derivatives may be used. Specific examples of commercially available conductive materials include acetylene black-based Chevron Chemical Company or Denka Singapore Private Limited, Gulf Oil Company products, Ketjenblack, EC-based Armac Company (Armak Company) product, Vulcan XC-72 Cabot Company (Cabot Company) product, Super-P (Product of Timcal Corporation), etc. can be used.

The binder is for well adhering the positive electrode active material to the current collector, it should be well soluble in a solvent, and should not only well form a conductive network between the positive electrode active material and the conductive material, but also have adequate impregnation property of the electrolyte. The binder may be all binders known in the art, and specifically, a fluororesin-based binder including polyvinylidene fluoride (PVdF) or polytetrafluoroethylene (PTFE); a rubber-based binder including a styrene-butadiene rubber, an acrylonitrile-butydiene rubber, and a styrene-isoprene rubber; Cellulose binders including carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, and regenerated cellulose; polyalcohol-based binders; Polyolefin-based binders including polyethylene and polypropylene; Polyimide-based binders, polyester-based binders, silane-based binders; may be one or more mixtures or copolymers selected from the group consisting of, but is not limited thereto.

The content of the binder may be 0.5 to 30% by weight based on the total weight of the positive electrode composition, but is not limited thereto. If the content of the binder resin is less than 0.5% by weight, the physical properties of the positive electrode may be lowered, and the positive electrode active material and the conductive material may fall off, and if it exceeds 30% by weight, the ratio of the active material and the conductive material in the positive electrode is relatively reduced. The battery capacity may be reduced, and the efficiency may be lowered by acting as a resistive element.

The positive electrode composition including the positive electrode active material, the conductive material, and the binder may be diluted in a predetermined solvent and coated on the positive electrode current collector using a conventional method known in the art. First, a positive electrode current collector is prepared. The positive electrode current collector generally has a thickness of 3 to 500 μm. Such a positive electrode current collector is not particularly limited as long as it has high conductivity without causing a chemical change in the battery. For example, stainless steel, aluminum, nickel, titanium, sintered carbon, or aluminum or stainless steel. A steel surface treated with carbon, nickel, titanium, silver, or the like may be used. The current collector may increase the adhesive force of the positive electrode active material by forming fine irregularities on its surface, and various forms such as a film, a sheet, a foil, a net, a porous body, a foam body, and a nonwoven body are possible.

Next, a slurry obtained by diluting a positive electrode composition including a positive electrode active material, a conductive material, and a binder in a solvent is applied on the positive electrode current collector. The positive electrode composition including the above-described positive electrode active material, conductive material, and binder may be mixed with a predetermined solvent to prepare a slurry. In this case, the solvent should be easy to dry and can dissolve the binder well, but it is most preferable that the cathode active material and the conductive material can be maintained in a dispersed state without dissolving. When the solvent dissolves the cathode active material, the sulfur in the slurry has a high specific gravity (D = 2.07), so sulfur sinks in the slurry, causing sulfur to collect on the current collector during coating, causing problems in the conductive network and causing problems in battery operation. There is this. The solvent (dispersion medium) may be water or an organic solvent, and the organic solvent may be at least one selected from the group consisting of dimethylformamide, isopropyl alcohol or acetonitrile, methanol, ethanol, and tetrahydrofuran.

Subsequently, there is no particular limitation on a method of applying the positive electrode composition in the slurry state, for example, doctor blade coating, dip coating, gravure coating, slit die coating, etc. coating), spin coating, comma coating, bar coating, reverse roll coating, screen coating, cap coating, etc. can be manufactured. The positive electrode composition that has been subjected to such a coating process is then dried through evaporation of the solvent (dispersion medium), the density of the coating film, and the adhesion between the coating film and the current collector. At this time, the drying is carried out according to a conventional method, it is not particularly limited.

electrolyte

The electrolyte constituting the lithium-sulfur battery of the present invention includes a solvent and a lithium salt, and may further include additives, if necessary. As the solvent, a conventional non-aqueous solvent serving as a medium through which ions involved in the electrochemical reaction of the battery can move may be used without any particular limitation. Examples of the non-aqueous solvent include carbonate-based solvents, ester-based solvents, ether-based solvents, ketone-based solvents, alcohol-based solvents, and aprotic solvents.

More specific examples, as the carbonate-based solvent, dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), methyl ethyl carbonate (MEC) ), ethylene carbonate (EC), propylene carbonate (PC), and butylene carbonate (BC), and the ester solvent is methyl acetate, ethyl acetate, n-propyl acetate, 1,1-dimethylethyl acetate, methyl There are propionate, ethyl propionate, γ-butyrolactone, decanolide, valerolactone, mevalonolactone and caprolactone, and the ether solvent is di ethyl ether, dipropyl ether, dibutyl ether, dimethoxymethane, trimethoxymethane, dimethoxyethane, diethoxyethane, diglyme, triglyme, tetraglyme, tetrahydrofuran, 2-methyltetrahydrofuran and polyethylene glycol dimethyl ether and the like. In addition, the ketone-based solvent includes cyclohexanone, the alcohol-based solvent includes ethyl alcohol and isopropyl alcohol, and the aprotic solvent includes nitriles such as acetonitrile, and amides such as dimethylformamide. Drew, dioxolanes such as 1,3-dioxolane (DOL), and sulfolane. The above non-aqueous solvents can be used alone or in mixture of two or more, and when two or more are mixed, the mixing ratio can be appropriately adjusted according to the performance of the intended battery, and 1,3-dioxolane and dimethoxyethane A solvent mixed in a volume ratio of 1:1 may be exemplified.

separator

A conventional separator may be interposed between the positive electrode and the negative electrode. The separator is a physical separator having a function of physically separating the electrodes, and can be used without any particular limitation as long as it is used as a conventional separator, and in particular, it is preferable to have low resistance to ion movement of the electrolyte and excellent electrolyte moisture content. In addition, the separator enables transport of lithium ions between the positive electrode and the negative electrode while separating or insulating the positive electrode and the negative electrode from each other. Such a separator may be made of a porous, non-conductive or insulating material. The separator may be an independent member such as a film, or a coating layer added to at least one of the anode and the cathode. Specifically, a porous polymer film, for example, a porous polymer film made of a polyolefin-based polymer such as ethylene homopolymer, propylene homopolymer, ethylene/butene copolymer, ethylene/hexene copolymer, and ethylene/methacrylate copolymer. It can be used alone or by laminating them, or a conventional porous nonwoven fabric, for example, a high melting point glass fiber, a nonwoven fabric made of polyethylene terephthalate fiber, etc. may be used, but is not limited thereto.

Hereinafter, preferred examples are presented to aid the understanding of the present invention, but the following examples are merely illustrative of the present invention, and it will be apparent to those skilled in the art that various changes and modifications are possible within the scope and spirit of the present invention, It goes without saying that such changes and modifications fall within the scope of the appended claims.

[Example 1] Preparation of porous polymer film coated with oxide semiconductor

An oxide semiconductor solution was prepared by dispersing 0.5 M Zn acetate dehydrate precursor in 100 mL of 2-methoxyethanol mixed with 0.5 M 2-ethanolamine, and then a polyimide radiation film with a thickness of 10 μm and a porosity of 80%. (PI radiation membrane, polymer membrane) was supported for 1 minute. Thereafter, it was dried for 1 hour using an oven set at 250° C. under an air atmosphere, and finally, heat-treated for 1 hour using a furnace set at 400° C. under an air atmosphere to prepare a porous polymer film coated with an oxide semiconductor. did. On the other hand, Figure 1 is an image of the oxide semiconductor coated polymer film according to an embodiment of the present invention observed with a scanning electron microscope (SEM) (A, B), the surface of the oxide semiconductor coating polymer film prepared in Example 1 is As shown in FIG. 1 .

[Comparative Example 1] Porous polymer membrane

A polyimide radiation film (PI radiation film, polymer film) in a bare state, not coated with an oxide semiconductor, was prepared. On the other hand, FIG. 2 is an image of the polyimide radiation film in a bare state according to Comparative Example observed with a scanning electron microscope (A, B), and the surface of the polyimide radiation film in the bare state of Comparative Example 1 is as shown in FIG. It was like

[Example 2, Comparative Example 2] Preparation of lithium-sulfur battery

A lithium-sulfur battery was prepared by bonding the oxide semiconductor-coated polymer film prepared in Example 1 to lithium metal and applying it as a negative interlayer, and then installing a positive electrode, an electrolyte, and a separator (Example 2). In addition, the bare polyimide radiation film prepared in Comparative Example 1 was bonded to lithium metal and applied as a negative interlayer, and then a positive electrode, an electrolyte, and a separator were installed to prepare a lithium-sulfur battery (Comparative Example 2) .

[Experimental Example 1] Evaluation of lifespan characteristics of lithium-sulfur batteries

The discharge current rates of the lithium-sulfur batteries prepared in Example 2 and Comparative Example 2 were sequentially changed to 0.1 C, 0.2 C, and 0.5 C to observe the lifespan characteristics of the batteries. 3 is a graph comparing and contrasting the lifespan characteristics of lithium-sulfur batteries according to an embodiment and a comparative example of the present invention. As shown in FIG. 3 , the lithium-sulfur battery of Example 2 to which an oxide semiconductor-coated polymer film was applied as an anode Inter Layer was compared to the lithium-sulfur battery of Comparative Example 2 in which a polyimide radiation film in a bare state was applied as an anode Inter Layer. , it was found that the capacity was improved in the high-rate section, and the cycle life characteristics were also improved.

[Experimental Example 2] Evaluation of discharge capacity of lithium-sulfur batteries

The battery capacity was evaluated by setting the discharge current rate of the lithium-sulfur batteries prepared in Example 2 and Comparative Example 2 to 0.5 C. 4 is a graph comparing and contrasting the discharge capacities of lithium-sulfur batteries according to an embodiment and a comparative example of the present invention. As shown in FIG. 4 , the lithium-sulfur battery of Example 2 to which an oxide semiconductor-coated polymer film was applied as an anode inter layer was compared to the lithium-sulfur battery of Comparative Example 2 in which a polyimide radiation film in a bare state was applied as an anode inter layer. , showed an effect of improving the discharge capacity, and through this, it was possible to confirm the advantage of using an oxide semiconductor having excellent lithium affinity.

Claims (10)

It is applied as a negative electrode structure of a lithium-sulfur battery and bonded to lithium metal,
a polymer membrane in which pores are formed; and
and an oxide semiconductor layer formed on the surface of the polymer film;
The oxide semiconductor-coated porous polymer film, characterized in that the oxide semiconductor layer has a thickness of 200 to 300 nm. The porous polymer film coated with an oxide semiconductor according to claim 1, wherein the oxide semiconductor-coated porous polymer film has a porosity of 70 to 95%. The method according to claim 1, wherein the oxide semiconductor is ZnO, SnO ₂ , In ₂ O ₃ and Ga ₂ O ₃ Characterized in that selected from the group consisting of, oxide semiconductor-coated porous polymer film. delete The porous polymer film coated with an oxide semiconductor according to claim 1, wherein the polymer forming the polymer film is polyimide. The porous polymer film coated with an oxide semiconductor according to claim 1, wherein the thickness of the polymer film excluding the oxide semiconductor is 1 to 100 μm. The porous polymer film coated with an oxide semiconductor according to claim 1, wherein the polymer film excluding the oxide semiconductor has a heat resistance temperature of 200° C. or higher. anode; An anode comprising a porous polymer film coated with lithium metal and the oxide semiconductor of claim 1 bonded to the lithium metal; an electrolyte interposed between the positive electrode and the negative electrode; and a separator; and a lithium-sulfur battery. a) dispersing the oxide semiconductor in a solvent to prepare an oxide semiconductor solution;
b) coating the prepared oxide semiconductor solution on the surface of the non-conductive and porous polymer film, drying and heat treatment to prepare an oxide semiconductor coating polymer film;
c) preparing an anode by bonding lithium metal to the prepared oxide semiconductor-coated polymer film; and
d) after installing the positive electrode to face the negative electrode, installing an electrolyte and a separator between the negative electrode and the positive electrode;
A method of manufacturing a lithium-sulfur battery, characterized in that the thickness of the oxide semiconductor layer in the oxide semiconductor-coated polymer film is 200 to 300 nm. The method of claim 9 , wherein the oxide semiconductor is selected from the group consisting of ZnO, SnO ₂ , In ₂ O ₃ and Ga ₂ O ₃ .

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