WO2016068641A1 - Lithium sulfur battery and method for producing same - Google Patents

Lithium sulfur battery and method for producing same Download PDF

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Publication number
WO2016068641A1
WO2016068641A1 PCT/KR2015/011558 KR2015011558W WO2016068641A1 WO 2016068641 A1 WO2016068641 A1 WO 2016068641A1 KR 2015011558 W KR2015011558 W KR 2015011558W WO 2016068641 A1 WO2016068641 A1 WO 2016068641A1
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Prior art keywords
lithium
sulfur battery
polymer electrolyte
gel polymer
lithium sulfur
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PCT/KR2015/011558
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French (fr)
Korean (ko)
Inventor
고동욱
박은경
채종현
양두경
권기영
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주식회사 엘지화학
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Priority to EP15856009.4A priority Critical patent/EP3206248B1/en
Priority to CN201580060061.XA priority patent/CN107078344B/en
Priority to US15/522,915 priority patent/US10446874B2/en
Priority claimed from KR1020150151556A external-priority patent/KR20160051652A/en
Publication of WO2016068641A1 publication Critical patent/WO2016068641A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0565—Polymeric materials, e.g. gel-type or solid-type
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566—Liquid materials
    • H01M10/0567—Liquid materials characterised by the additives
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present invention relates to a lithium sulfur battery which is prevented from deterioration due to a shuttle effect and a method of manufacturing the same.
  • the present invention includes a gel polymer electrolyte configured to suppress migration of a polysulfide-based material to the negative electrode, and prevents loss of polysulfide formed on the surface of the positive electrode during charge and discharge reaction, thereby improving lifespan characteristics, and a lithium sulfur battery. It relates to a manufacturing method.
  • lithium sulfur batteries have a low discharge potential of 2V, they are attracting attention as next-generation electric vehicle batteries because of their excellent safety, low cost of active materials, and a discharge capacity of 2,600 Wh / kg.
  • Lithium sulfur batteries usually use a sulfur-based compound having a sulfur-sulfur bond as a positive electrode 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 desorbed
  • a secondary battery used as a negative electrode active material an oxidation-reduction in which a reduction in the number of oxides of S occurs during the reduction reaction (discharge) and an oxidation-reduction in which the number of oxides of S decreases during the oxidation reaction (charge). Reactions are used to store and generate electrical energy.
  • lithium sulfur battery has a problem in that lithium polysulfide formed at the positive electrode is lost out of the positive electrode reaction region during the charge and discharge reaction, thereby deteriorating the life characteristics.
  • Li-S cells produce polysulfide intermediates when charged and discharged. Polysulfide elutes into the electrolyte, diffuses to the cathode surface and reacts with the cathode to produce insoluble Li 2 S and Li 2 S 2 . Due to this reaction, sulfur used as the cathode active material is lost and battery performance is reduced. This phenomenon is called a shuttle effect.
  • the lithium sulfur battery is a sulfur-sulfur chemical bond is gradually disconnected during the discharge and transition to a bond between sulfur and lithium
  • the lithium polysulfides is LiSx or negative ions dissolved in the electrolyte (LiS x -, S x 2 -) when the spread is possible, and a lithium polysulfide that diffuses from the sulfur cathode in the form of the out an electrochemical reaction area of the anode electrocatalyst in the anode
  • the amount of sulfur involved in the chemical reaction is reduced, resulting in capacity loss.
  • lithium polysulfide reacts with the lithium metal negative electrode due to the continuous charge and discharge reaction, and thus lithium sulfide (Li 2 S) is fixed on the surface of the lithium metal, thereby lowering the reaction activity and deteriorating dislocation characteristics.
  • the prior art for solving the lithium polysulfide loss problem of the lithium sulfur battery can be largely divided into three techniques.
  • First a method of delaying the outflow of the positive electrode active material by adding an additive having a property of adsorbing sulfur to the positive electrode mixture, wherein the additive used is active carbon fiber, transition metal chalcogenide, alumina, silica, etc. There is this.
  • Secondly there is a technique of surface-treating the sulfur surface with a material containing hydroxide, oxyhydroxide of the coating element, oxycarbonate of the coating element or hydroxycarbonate of the coating element.
  • the method of fabricating the conductive material into the nanostructures is complicated and expensive, and the volume occupied by the carbon nanostructures causes a loss in the volume capacity of the battery, and the nanostructures are also rolled in the cell manufacturing process. There is a risk of loss of function in the process.
  • an anode and a cathode disposed to face each other, a separator positioned between the anode and the cathode, and a gel polymer electrolyte positioned between the separator and the anode, wherein the gel polymer electrolyte is LiNO 3 It provides a lithium sulfur battery comprising a.
  • the gel polymer electrolyte may be coated on the anode surface or the separator surface.
  • the gel polymer electrolyte may include a polymer matrix and an organic solvent and a lithium salt supported on the polymer matrix.
  • the polymer matrix may be a polymer in which trimethylolpropane ethoxylate triacrylate monomer is polymerized.
  • a monomer, an organic solvent, a lithium salt, and LiNO 3 are mixed, and the mixture is coated on the cathode or the separator and cured to form a gel polymer electrolyte positioned between the separator and the anode. It provides a lithium sulfur battery manufacturing method comprising the step of manufacturing.
  • the monomer may be trimethylolpropane ethoxylate triacrylate.
  • the solvent may be any one selected from the group consisting of TEGDME (Triethylene glycol dimethyl ether), DOL (Dioxolane), DME (Dimethoxyethane) and a mixed solution thereof.
  • TEGDME Triethylene glycol dimethyl ether
  • DOL Dioxolane
  • DME Dimethoxyethane
  • the lithium salt may be lithium bis-trifluoromethanesulfonimide (LiTFSI).
  • the present invention relates to a lithium sulfur battery which is prevented from deterioration due to a shuttle effect, and a method for manufacturing the same, including a gel polymer electrolyte configured to suppress migration of a polysulfide-based material to the negative electrode, and thus a charge and discharge reaction.
  • a gel polymer electrolyte configured to suppress migration of a polysulfide-based material to the negative electrode, and thus a charge and discharge reaction.
  • FIG. 1 is a schematic cross-sectional view showing a lithium sulfur battery in which a gel polymer layer of the present invention is formed between an anode and a separator.
  • FIGS. 2 to 4 are graphs showing the results of charge and discharge experiments of the lithium sulfur batteries prepared in Example 1 and Comparative Example 1 of the present invention, and FIGS. 2 to 4 show results at 1 cycle, 2 cycles, and 12 cycles, respectively.
  • FIG. 1 is a schematic cross-sectional view showing a lithium sulfur battery in which a gel polymer layer of the present invention is formed between an anode and a separator.
  • a lithium sulfur battery according to an exemplary embodiment of the present invention is interposed between a positive electrode 120 and a negative electrode 150 disposed between the positive electrode 120 and the negative electrode 150.
  • the cathode 120 may include a cathode current collector 121 and a cathode active material layer 122 disposed on the cathode current collector 121 and including a cathode active material and optionally a conductive material and a binder. have.
  • the cathode current collector 121 it may be preferable to use foamed aluminum, foamed nickel, and the like, which have excellent conductivity.
  • the cathode active material layer 122 may include elemental sulfur (S8), a sulfur-based compound, or a mixture thereof as the cathode active material.
  • the positive electrode active material layer 122 is a conductive material for allowing electrons to move smoothly in the positive electrode 120 together with the positive electrode active material, and the binding force between the positive electrode active material or between the positive electrode active material and the positive electrode current collector 110. It may further include a binder for increasing the.
  • the conductive material may be a carbon-based material such as carbon black, acetylene black, or ketjen black; Or it may be a conductive polymer such as polyaniline, polythiophene, polyacetylene, polypyrrole, the conductive material may be preferably contained in 5 to 20% by weight based on the total weight of the positive electrode active material layer. If the content of the conductive material is less than 5% by weight, the conductivity improvement effect according to the use of the conductive material is insignificant, whereas if the content of more than 20% by weight, the content of the positive electrode active material is relatively small, there is a fear that the capacity characteristics.
  • the binder may be poly (vinyl acetate), polyvinyl alcohol, polyethylene oxide, polyvinylpyrrolidone, alkylated polyethylene oxide, crosslinked polyethylene oxide, polyvinyl ether, poly (methyl methacrylate), poly Vinylidene fluoride, copolymer of polyhexafluoropropylene and polyvinylidene fluoride (trade name: Kynar), poly (ethyl acrylate), polytetrafluoroethylene, polyvinylchloride, polyacrylonitrile, polyvinylpyridine , Polystyrene, derivatives thereof, blends, copolymers and the like can be used.
  • the binder may be preferably contained in 5 to 20% by weight based on the total weight of the positive electrode active material layer.
  • the content of the binder is less than 5% by weight, the effect of improving the binding strength between the positive electrode active material or between the positive electrode active material and the current collector according to the use of the binder is insignificant, whereas when the content of the binder exceeds 20% by weight, the content of the positive electrode active material is relatively small. There is a risk of deterioration of characteristics.
  • the positive electrode 120 as described above may be manufactured according to a conventional method, and specifically, a positive electrode active material layer forming composition prepared by mixing the positive electrode active material, the conductive material, and the binder on an organic solvent, on the positive electrode current collector. After application, it can be prepared by drying and optionally rolling.
  • the organic solvent the cathode active material, the binder, and the conductive material may be uniformly dispersed, and it is preferable to use one that is easily evaporated. Specifically, acetonitrile, methanol, ethanol, tetrahydrofuran, water, isopropyl alcohol, etc. are mentioned.
  • the negative electrode 150 is a negative electrode active material, a material capable of reversibly intercalating or deintercalating lithium ions, and can react with lithium ions to form a reversible lithium-containing compound And a material selected from the group consisting of lithium metal and lithium alloy.
  • any carbon-based negative electrode active material generally used in the lithium sulfur battery may be used, and specific examples thereof include crystalline carbon, Amorphous carbons or these may be used together.
  • a representative example of a material capable of reacting with lithium ions to reversibly form a lithium-containing compound may include, but is not limited to, tin oxide (SnO 2 ), titanium nitrate, silicon (Si), and the like.
  • the alloy of the lithium metal may be an alloy of lithium with a metal of Si, Al, Sn, Pb, Zn, Bi, In, Mg, Ga, or Cd.
  • the negative electrode 150 may optionally further include a binder together with the negative electrode active material.
  • the binder acts as a paste for the negative electrode active material, mutual adhesion between the active materials, adhesion between the active material and the current collector, and a buffering effect on the expansion and contraction of the active material.
  • the binder is the same as described above.
  • the negative electrode 150 may further include a negative electrode current collector 152 for supporting the negative electrode active material layer 151 including the negative electrode active material and the binder.
  • the negative electrode current collector 152 may be specifically selected from the group consisting of copper, aluminum, stainless steel, titanium, silver, palladium, nickel, alloys thereof, and combinations thereof.
  • the stainless steel may be surface treated with carbon, nickel, titanium, or silver, and an aluminum-cadmium alloy may be used as the alloy.
  • calcined carbon, a nonconductive polymer surface-treated with a conductive material, or a conductive polymer may be used.
  • the cathode 150 may be a thin film of lithium metal.
  • the separator 140 is a physical separator having a function of physically separating an electrode, and can be used without particular limitation as long as it is generally used as a separator in a lithium sulfur battery. It is desirable to have low resistance to migration and excellent electrolyte-moisture capability.
  • 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 may be used alone. It may be used as a lamination or or a conventional porous non-woven fabric, for example, a non-woven fabric made of glass fibers, polyethylene terephthalate fibers of high melting point, etc. may be used, but is not limited thereto.
  • the lithium sulfur battery may further include an electrolyte immersed in the separator 140.
  • the electrolyte may include an organic solvent and a lithium salt.
  • the organic solvent may be a polar solvent such as an aryl compound, bicyclic ether, acyclic carbonate, sulfoxide compound, lactone compound, ketone compound, ester compound, sulfate compound, sulfite compound and the like.
  • a polar solvent such as an aryl compound, bicyclic ether, acyclic carbonate, sulfoxide compound, lactone compound, ketone compound, ester compound, sulfate compound, sulfite compound and the like.
  • the organic solvent may be 1,2-dimethoxyethane, 1,2-diethoxyethane, 1,2-dibutoxyethane, dioxolane (Dioxolane, DOL), 1,4-dioxane, tetrahydrofuran , 2-methyltetrahydrofuran, dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), methyl propyl carbonate (MPC), ethyl propyl carbonate, dipropyl carbonate, butyl ethyl carbonate, ethyl propano EP, toluene, xylene, dimethyl ether (DME), diethyl ether, triethylene glycol monomethyl ether (TEGME), diglyme, tetraglyme, hexamethyl phosphoric tree Amide (hexamethyl phosphoric triamide), gamma butyrolactone (GBL), acetonitrile
  • a mixed solvent of triethylene glycol monomethyl ether / dioxolane / dimethyl ether may be more preferable.
  • the lithium salt may be used without particular limitation as long as it is a compound capable of providing lithium ions used in a lithium secondary battery.
  • the lithium salt is LiPF 6 , LiClO 4 , LiAsF 6 , LiBF 4 , LiSbF 6 , LiAl0 4 , LiAlCl 4 , LiCF 3 SO 3 , LiC 4 F 9 SO 3 , LiN (C 2 F 5 SO 3 ) 2 LiN (C 2 F 5 SO 2 ) 2 (Lithium bis (perfluoroethylsulfonyl) imide, BETI), LiN (CF 3 SO 2 ) 2 (Lithium bis (Trifluoromethanesulfonyl) imide, LiTFSI), LiN (C a F 2a + 1 SO 2 ) (C b F 2b + 1 SO 2 ) (where a and b are natural numbers, preferably 1 ⁇ a ⁇ 20 and 1 ⁇ b ⁇ 20), lithium poly [4,4
  • the lithium salt may be preferably included in 10 to 35% by weight based on the total weight of the electrolyte. If the content of the lithium salt is less than 10% by weight, the conductivity of the electrolyte is lowered and the performance of the electrolyte is lowered. When the content of the lithium salt is more than 35% by weight, the viscosity of the electrolyte is increased to reduce the mobility of lithium ions.
  • the lithium sulfur battery includes a gel polymer electrolyte 130 positioned between the separator 140 and the positive electrode 120.
  • the gel polymer electrolyte 130 is supported by the electrolyte in a polymer matrix.
  • the polymer matrix is not particularly limited, but may be a polymer resin including at least one or more of a polyethylene oxide-based polymer compound, a polyorganosiloxane chain, or a polyoxyalkylene chain, preferably trimethylolpropane. It may be prepared by polymerizing the toxyl triacrylate monomer. When the polymer of the trimethylolpropane ethoxylate triacrylate monomer is used as the polymer matrix, the ion dissociation ability and the impregnation ability of the electrolyte of the polymer matrix are good, thereby improving ion conductivity.
  • the trimethylolpropane ethoxylate triacrylate may have a weight average molecular weight of 200 to 1000 g / mol, preferably 300 to 700 g / mol.
  • weight average molecular weight of the trimethylolpropane ethoxylate triacrylate is less than 200g / mol may be reduced ionic conductivity, if it exceeds 1000g / mol physical inhibitory effect can be reduced.
  • the electrolyte supported in the gel polymer electrolyte 130 may include an organic solvent and a lithium salt. Since the description of the organic solvent and the lithium salt is the same as described above, repeated description is omitted.
  • the electrolyte further comprises LiNO 3 .
  • the electrolyte may improve the shuttle suppression effect.
  • the electrolyte may include 1 to 50% by weight of LiNO 3 based on the total weight of the electrolyte, preferably 1.5 to 10% by weight. When the content of LiNO 3 is less than 1% by weight, the shuttle inhibitory effect may not appear, and when the content of LiNO 3 exceeds 50% by weight, side reactions due to decomposition of LiNO 3 may occur.
  • the gel polymer electrolyte 130 may be prepared by mixing the monomer, the organic solvent, the lithium salt, and the LiNO 3 forming the polymer matrix, and curing the mixture. The curing may be thermal curing or photo curing. To this end, the mixture may further include a heat curing agent or a light curing agent.
  • the mixture may include the organic solvent and the lithium salt in a weight ratio of 10: 1 to 1: 1, preferably in a weight ratio of 4: 1 to 2: 1. In both cases where the weight ratio of the organic solvent is less than 10: 1 and more than 1: 1, the ionic conductivity may be reduced.
  • the mixture may include the organic solvent including the lithium salt and the monomer in a weight ratio of 99: 1 to 10:90, preferably in a weight ratio of 95: 5 to 70:30.
  • the weight ratio of the monomer is less than 99: 1, the shuttle inhibitory effect may be reduced, and when it exceeds 10:90, the battery capacity may be reduced due to the decrease in ion conductivity.
  • the gel polymer electrolyte 130 may be interposed between the separator 140 and the anode 120 after the mixture is prepared as an independent film, and the mixture may be disposed on the separator 140 or the anode 120. It may be prepared by curing after coating.
  • the method of coating the mixture on the separator 140 or the anode 120 is not particularly limited, but the screen printing method, the spray coating method, the coating method using a doctor blade, the gravure coating method, the dip coating method, and the silk screen method , Painting, coating using a slit die, spin coating, roll coating, transfer coating method and the like can be used.
  • the curing may be thermal curing or light curing, in the case of the thermal curing, the curing may be made at 60 to 200 °C, preferably at 60 to 150 °C. If the curing temperature is less than 60 °C may not be sufficiently cured to reduce the physical shuttle inhibitory effect, if it exceeds 150 °C may be reduced ionic conductivity and capacity due to volatilization of the impregnated electrolyte.
  • Sulfur (average particle size: 40 ⁇ m) was first prepared using a ball mill with Super P in ethanol.
  • the composite, conductive material, binder, and mixer were mixed to prepare a composition for forming a cathode active material layer.
  • carbon black was used as the conductive material
  • SBR was used as the binder
  • the mixing ratio was 75: 20: 5 in the weight ratio of the composite: conductive material: binder.
  • the prepared positive electrode active material layer-forming composition was applied to an aluminum current collector and then dried to prepare a positive electrode (energy density of positive electrode: 1.0 mAh / cm 2).
  • a lithium metal thin film was prepared as a negative electrode.
  • Sulfur (average particle size: 40 ⁇ m) was first prepared using a ball mill with Super P in ethanol.
  • the composite, conductive material, binder, and mixer were mixed to prepare a composition for forming a cathode active material layer.
  • carbon black was used as the conductive material
  • SBR was used as the binder
  • the mixing ratio was 75: 20: 5 in the weight ratio of the composite: conductive material: binder.
  • the prepared positive electrode active material layer-forming composition was applied to an aluminum current collector and then dried to prepare a positive electrode (energy density of positive electrode: 1.0 mAh / cm 2).
  • a lithium metal thin film was prepared as a negative electrode.
  • an electrolyte was injected into the case to prepare a lithium sulfur battery.
  • An electrolyte added in weight ratio was used.
  • the ion conductivity of the electrolyte prepared in the lithium sulfur batteries prepared in Examples 1 to 4 was manufactured by using a coin cell using SUS as an electrode, and measured by electrochemical impedance spectroscopy (EIS), and the results were as follows. Table 1 shows.
  • Organic solvent monomer weight ratio
  • Lithium salt Organic solvent weight ratio Ion conductivity
  • Example 1 90:10 1: 3 1.1 ⁇ 10 -3 S / cm
  • Example 2 85:15 1: 3 4.1 ⁇ 10 -4 S / cm
  • Example 3 80:20 1: 3 6.6 ⁇ 10 -5 S / cm
  • Example 4 85:15 1: 2 1.8 ⁇ 10 -4 S / cm
  • Example 1 Referring to Table 1, it can be seen that the ion conductivity of the electrolyte prepared in Example 1 is the most excellent.
  • the lithium sulfur battery to which the gel polymer electrolyte of the present invention is applied has an improved coulombic efficiency, initial discharge capacity, reproducibility, etc. due to the physical inhibitory effect of the shuttle reaction. have.
  • the present invention relates to a lithium sulfur battery which is prevented from deterioration due to a shuttle effect and a method of manufacturing the same.
  • the lithium sulfur battery includes a gel polymer electrolyte configured to suppress migration of a polysulfide-based material to the negative electrode, thereby preventing loss of polysulfide formed on the surface of the positive electrode during charge and discharge reaction, thereby improving lifespan characteristics.

Abstract

The present invention relates to a lithium sulfur battery, comprising: an anode and a cathode which are disposed opposite to each other; a separation membrane positioned between the anode and the cathode; and a gel polymer electrolyte positioned between the separation membrane and the cathode, wherein the gel polymer electrolyte includes LiNO3. The present invention relates to a lithium sulfur battery which prevents degeneration by a shuttle effect, and the lithium sulfur battery comprises a gel polymer electrolyte configured to inhibit the transfer of a polysulfide-based material to the anode, so that the lithium sulfur battery can prevent loss of the polysulfide produced on the surface of the cathode at the time of charge and discharge reactions, whereby the lifespan characteristics of the lithium sulfur battery can be enhanced.

Description

리튬 황 전지 및 이의 제조 방법Lithium Sulfur Battery and Method for Manufacturing the Same
본 발명은 셔틀 효과(shuttle effect)에 의한 퇴화가 방지된 리튬 황 전지 및 이의 제조 방법에 관한 것이다. 본 발명은 폴리설파이드계 물질의 상기 음극으로의 이동을 억제하도록 구성된 겔 고분자 전해질을 포함하여, 충방전 반응시 양극 표면에 형성되는 폴리설파이드의 유실을 방지하여 수명 특성을 향상한 리튬 황 전지 및 이의 제조 방법에 관한 것이다.The present invention relates to a lithium sulfur battery which is prevented from deterioration due to a shuttle effect and a method of manufacturing the same. The present invention includes a gel polymer electrolyte configured to suppress migration of a polysulfide-based material to the negative electrode, and prevents loss of polysulfide formed on the surface of the positive electrode during charge and discharge reaction, thereby improving lifespan characteristics, and a lithium sulfur battery. It relates to a manufacturing method.
일반적으로 리튬 황 전지는 2V대의 낮은 방전 전위를 갖고 있음에도 불구하고, 안전성이 우수하고 활물질이 저렴하며 2,600Wh/kg의 방전용량을 가짐으로 인해 차세대 전기 자동차용 전지로 주목받고 있다.In general, although lithium sulfur batteries have a low discharge potential of 2V, they are attracting attention as next-generation electric vehicle batteries because of their excellent safety, low cost of active materials, and a discharge capacity of 2,600 Wh / kg.
리튬 황 전지는 보통 황-황 결합(Sulfur-Sulfur bond)을 갖는 황 계열 화합물을 양극 활물질로 사용하고, 리튬과 같은 알카리 금속 또는 리튬 이온 등과 같은 금속 이온의 삽입 및 탈리 현상이 일어나는 탄소계 물질을 음극 활물질로 사용하는 이차 전지로서, 환원 반응시(방전시) S-S 결합이 끊어지면서 S의 산화수가 감소하고, 산화 반응시(충전시) S의 산화수가 증가하면서 S-S 결합이 다시 형성되는 산화-환원 반응을 이용하여 전기적 에너지를 저장 및 생성한다.Lithium sulfur batteries usually use a sulfur-based compound having a sulfur-sulfur bond as a positive electrode 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 desorbed As a secondary battery used as a negative electrode active material, an oxidation-reduction in which a reduction in the number of oxides of S occurs during the reduction reaction (discharge) and an oxidation-reduction in which the number of oxides of S decreases during the oxidation reaction (charge). Reactions are used to store and generate electrical energy.
그러나, 이러한 리튬 황 전지는 충방전 반응 중에 양극에서 형성된 리튬 폴리설파이드가 양극 반응 영역 밖으로 유실되는 현상이 발생되어 수명 특성이 저하되는 문제점을 가지고 있다. Li-S 전지는 충방전될 때 폴리설파이드 중간체가 생성된다. 폴리설파이드는 전해질에 용출되어 음극 표면으로 확산 하고 음극과 반응하여 불용성의 Li2S 및 Li2S2를 생성한다. 이러한 반응으로 인해 양극 활물질로 사용되는 황이 손실되고 전지 성능이 줄어들게 되는데 이러한 현상을 서플 효과(shuttle effect)라 한다.However, such a lithium sulfur battery has a problem in that lithium polysulfide formed at the positive electrode is lost out of the positive electrode reaction region during the charge and discharge reaction, thereby deteriorating the life characteristics. Li-S cells produce polysulfide intermediates when charged and discharged. Polysulfide elutes into the electrolyte, diffuses to the cathode surface and reacts with the cathode to produce insoluble Li 2 S and Li 2 S 2 . Due to this reaction, sulfur used as the cathode active material is lost and battery performance is reduced. This phenomenon is called a shuttle effect.
구체적으로 설명하면, 리튬 황 전지는 방전 중에 황-황 화학결합이 점차적으로 단절되고 황-리튬 간의 결합으로 전이되는데, 그 중간과정에서 형성된 리튬 폴리설파이드(Li2Sx, x=8,6,4,2)는 극성이 강한 물질로서 친수성 용매와 쉽게 결합한다. 전해질에 용해된 리튬 폴리설파이드는 LiSx 또는 음이온(LiSx -, Sx 2 -)의 형태로 확산이 가능하며, 유황 양극으로부터 리튬 폴리설파이드가 확산되면 양극의 전기화학 반응 영역을 벗어나게 되어 양극에서 전기화학 반응에 참여하는 유황의 양이 감소하게 되고, 결국 용량감소(capacity loss)를 초래하게 된다. 그리고 지속적인 충방전 반응으로 리튬 폴리설파이드가 리튬 금속 음극과 반응하여 리튬 금속 표면에 리튬 설파이드(Li2S)가 고착됨으로 인해 반응 활성도가 낮아지고 전위 특성이 나빠지는 문제점이 있다.Specifically, the lithium sulfur battery is a sulfur-sulfur chemical bond is gradually disconnected during the discharge and transition to a bond between sulfur and lithium, lithium polysulfide (Li 2 S x , x = 8,6, 4,2) is a highly polar substance that easily binds to hydrophilic solvents. The lithium polysulfides is LiSx or negative ions dissolved in the electrolyte (LiS x -, S x 2 -) when the spread is possible, and a lithium polysulfide that diffuses from the sulfur cathode in the form of the out an electrochemical reaction area of the anode electrocatalyst in the anode The amount of sulfur involved in the chemical reaction is reduced, resulting in capacity loss. In addition, the lithium polysulfide reacts with the lithium metal negative electrode due to the continuous charge and discharge reaction, and thus lithium sulfide (Li 2 S) is fixed on the surface of the lithium metal, thereby lowering the reaction activity and deteriorating dislocation characteristics.
이러한 리튬 황 전지의 리튬 폴리설파이드 유실 문제를 해결하기 위한 종래 기술은 크게 3가지 기술로 구분할 수 있다. 첫째, 황을 흡착하는 성질을 지니는 첨가제를 양극 합제에 첨가함으로 양극 활물질의 유출을 지연시키는 방법으로, 이때 사용되는 첨가제는 활성 탄소 섬유(active carbon fiber), 전이 금속 칼코게나이드, 알루미나, 실리카 등이 있다. 둘째, 황 표면을 하이드록사이드, 코팅 원소의 옥시하이드록사이드, 코팅 원소의 옥시카보네이트 또는 코팅 원소의 하이드록시카보네이트를 포함하는 물질로 표면 처리하는 기술이 있다. 셋째, 탄소재를 나노구조체로 제조하여 나노 구조의 모세관에 리튬 폴리설파이드를 구속하는 방법이 있다.The prior art for solving the lithium polysulfide loss problem of the lithium sulfur battery can be largely divided into three techniques. First, a method of delaying the outflow of the positive electrode active material by adding an additive having a property of adsorbing sulfur to the positive electrode mixture, wherein the additive used is active carbon fiber, transition metal chalcogenide, alumina, silica, etc. There is this. Secondly, there is a technique of surface-treating the sulfur surface with a material containing hydroxide, oxyhydroxide of the coating element, oxycarbonate of the coating element or hydroxycarbonate of the coating element. Third, there is a method of restoring lithium polysulfide to the nanostructured capillary by preparing a carbon material as a nanostructure.
그러나, 종래 기술 중 양극에 황을 흡착하는 첨가제를 추가하는 방법은 전기전도성 열화 문제와 첨가제로 인한 전지 부반응의 위험성을 가지며, 또한 비용적인 측면에서도 바람직하지 못하다.However, in the prior art, a method of adding an additive that adsorbs sulfur to the positive electrode has a problem of deterioration of electrical conductivity and a risk of side reaction due to the additive, which is also undesirable in terms of cost.
그리고, 황 표면을 소정의 물질로 표면 처리하는 종래 기술은 처리 과정 중 유황이 유실되는 문제가 있으며, 고비용이 소요되는 단점이 있다.In addition, the prior art of surface-treating the surface of the sulfur with a predetermined material has a problem that the sulfur is lost during the process, there is a disadvantage that the high cost.
마지막으로, 도전재를 나노구조체로 제작하는 방법은 제조 과정이 복잡하고 고비용이 소요되며, 탄소 나노구조체가 차지하는 부피로 인해 전지의 부피 용량 손실이 발생하게 되고, 또한 나노구조체가 전지 제조 과정의 압연 공정에서 기능을 상실할 우려가 있다.Finally, the method of fabricating the conductive material into the nanostructures is complicated and expensive, and the volume occupied by the carbon nanostructures causes a loss in the volume capacity of the battery, and the nanostructures are also rolled in the cell manufacturing process. There is a risk of loss of function in the process.
본 발명의 목적은 폴리설파이드의 셔틀(shuttle) 반응을 효과적으로 차단할 수 있는 리튬 황 전지 및 이의 제조 방법을 제공하는 것이다.It is an object of the present invention to provide a lithium sulfur battery and a method of manufacturing the same that can effectively block the shuttle reaction of polysulfide.
본 발명의 일 실시예에 따르면, 서로 대향 배치되는 양극과 음극, 상기 양극과 음극 사이에 위치하는 분리막, 그리고 상기 분리막과 양극 사이에 위치하는 겔 고분자 전해질을 포함하며, 상기 겔 고분자 전해질은 LiNO3를 포함하는 리튬 황 전지를 제공한다.According to an embodiment of the present invention, an anode and a cathode disposed to face each other, a separator positioned between the anode and the cathode, and a gel polymer electrolyte positioned between the separator and the anode, wherein the gel polymer electrolyte is LiNO 3 It provides a lithium sulfur battery comprising a.
상기 겔 고분자 전해질은 상기 양극 표면 또는 상기 분리막 표면에 코팅되어 있을 수 있다.The gel polymer electrolyte may be coated on the anode surface or the separator surface.
상기 겔 고분자 전해질은 고분자 매트릭스 및 상기 고분자 매트릭스에 지지된 유기용매와 리튬염을 포함할 수 있다.The gel polymer electrolyte may include a polymer matrix and an organic solvent and a lithium salt supported on the polymer matrix.
상기 고분자 매트릭스는 트리메틸올프로판 에톡실레이트 트리아크릴레이트 단량체가 중합된 고분자일 수 있다.The polymer matrix may be a polymer in which trimethylolpropane ethoxylate triacrylate monomer is polymerized.
본 발명의 또 다른 일 실시예에 따르면, 단량체, 유기용매, 리튬염 및 LiNO3를 혼합하고, 상기 혼합물을 양극 또는 분리막 위에 도포한 후 경화시켜, 상기 분리막과 양극 사이에 위치하는 겔 고분자 전해질을 제조하는 단계를 포함하는, 리튬 황 전지 제조 방법을 제공한다.According to another embodiment of the present invention, a monomer, an organic solvent, a lithium salt, and LiNO 3 are mixed, and the mixture is coated on the cathode or the separator and cured to form a gel polymer electrolyte positioned between the separator and the anode. It provides a lithium sulfur battery manufacturing method comprising the step of manufacturing.
상기 단량체는 트리메틸올프로판 에톡실레이트 트리아크릴레이트일 수 있다.The monomer may be trimethylolpropane ethoxylate triacrylate.
상기 용매는 TEGDME(Triethylene glycol dimethyl ether), DOL(Dioxolane), DME(Dimethoxyethane) 및 이들의 혼합 용액으로 이루어진 군에서 선택되는 어느 하나일 수 있다.The solvent may be any one selected from the group consisting of TEGDME (Triethylene glycol dimethyl ether), DOL (Dioxolane), DME (Dimethoxyethane) and a mixed solution thereof.
상기 리튬염은 LiTFSI(lithium bis-trifluoromethanesulfonimide)일 수 있다. The lithium salt may be lithium bis-trifluoromethanesulfonimide (LiTFSI).
본 발명은 셔틀 효과(shuttle effect)에 의한 퇴화가 방지된 리튬 황 전지 및 이의 제조 방법에 관한 것으로서, 폴리설파이드계 물질의 상기 음극으로의 이동을 억제하도록 구성된 겔 고분자 전해질을 포함하여, 충방전 반응시 양극 표면에 형성되는 폴리설파이드의 유실을 방지하여 리튬 황 전지의 수명 특성을 향상시킬 수 있다.The present invention relates to a lithium sulfur battery which is prevented from deterioration due to a shuttle effect, and a method for manufacturing the same, including a gel polymer electrolyte configured to suppress migration of a polysulfide-based material to the negative electrode, and thus a charge and discharge reaction. By preventing the loss of polysulfide formed on the surface of the positive electrode can improve the life characteristics of the lithium sulfur battery.
도 1은 본 발명의 겔 고분자 층을 양극과 분리막 사이에 형성시킨 리튬 황 전지를 나타내는 개략 단면도이다.1 is a schematic cross-sectional view showing a lithium sulfur battery in which a gel polymer layer of the present invention is formed between an anode and a separator.
도 2 내지 4는 본 발명의 실시예 1 및 비교예 1에서 제조된 리튬 황 전지의 충방전 실험 결과를 나타내는 그래프로서, 도 2 내지 4는 각각 1 사이클, 2 사이클 및 12 사이클에서의 결과이다.2 to 4 are graphs showing the results of charge and discharge experiments of the lithium sulfur batteries prepared in Example 1 and Comparative Example 1 of the present invention, and FIGS. 2 to 4 show results at 1 cycle, 2 cycles, and 12 cycles, respectively.
이하, 본 발명이 속하는 기술 분야에서 통상의 지식을 가진 자가 용이하게 실시할 수 있도록 본 발명의 실시예에 대하여 상세히 설명한다. 그러나 본 발명은 여러 가지 상이한 형태로 구현될 수 있으며 여기에서 설명하는 실시예에 한정되지 않는다.Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily practice the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.
도 1은 본 발명의 겔 고분자 층을 양극과 분리막 사이에 형성시킨 리튬 황 전지를 나타내는 개략 단면도이다.1 is a schematic cross-sectional view showing a lithium sulfur battery in which a gel polymer layer of the present invention is formed between an anode and a separator.
이하 도 1을 참조하여 설명하면, 본 발명의 일 실시예에 따른 리튬 황 전지는 서로 대향 배치되는 양극(120)과 음극(150), 상기 양극(120)과 음극(150) 사이에 개재되어 위치하는 분리막(140), 및 상기 분리막(140)과 양극(120) 사이에 겔 고분자 전해질(130)을 포함한다.Hereinafter, referring to FIG. 1, a lithium sulfur battery according to an exemplary embodiment of the present invention is interposed between a positive electrode 120 and a negative electrode 150 disposed between the positive electrode 120 and the negative electrode 150. The separator 140, and a gel polymer electrolyte 130 between the separator 140 and the anode 120.
상기 양극(120)은 일 예로서, 양극집전체(121) 및 상기 양극집전체(121) 위에 위치하며, 양극활물질과 선택적으로 도전재 및 바인더를 포함하는 양극활물질층(122)을 포함할 수 있다. For example, the cathode 120 may include a cathode current collector 121 and a cathode active material layer 122 disposed on the cathode current collector 121 and including a cathode active material and optionally a conductive material and a binder. have.
상기 양극집전체(121)로는 구체적으로 우수한 도전성을 갖는 발포 알루미늄, 발포 니켈 등을 사용하는 것이 바람직할 수 있다.As the cathode current collector 121, it may be preferable to use foamed aluminum, foamed nickel, and the like, which have excellent conductivity.
또, 상기 양극활물질층(122)은 양극활물질로서 황 원소(elemental sulfur, S8), 황 계열 화합물 또는 이들의 혼합물을 포함할 수 있다. 상기 황 계열 화합물은 구체적으로, Li2Sn(n≥1), 유기황 화합물 또는 탄소-황 폴리머((C2Sx)n: x=2.5∼50, n≥2) 등일 수 있다.In addition, the cathode active material layer 122 may include elemental sulfur (S8), a sulfur-based compound, or a mixture thereof as the cathode active material. Specifically, the sulfur-based compound may be Li 2 S n (n ≧ 1), an organic sulfur compound or a carbon-sulfur polymer ((C 2 S x ) n : x = 2.5 to 50, n ≧ 2), or the like.
또, 상기 양극활물질층(122)은 상기한 양극활물질과 함께 전자가 상기 양극(120) 내에서 원활하게 이동하도록 하기 위한 도전재, 및 양극활물질간 또는 양극활물질과 양극집전체(110)와의 결착력을 높이기 위한 바인더를 더 포함할 수 있다. In addition, the positive electrode active material layer 122 is a conductive material for allowing electrons to move smoothly in the positive electrode 120 together with the positive electrode active material, and the binding force between the positive electrode active material or between the positive electrode active material and the positive electrode current collector 110. It may further include a binder for increasing the.
상기 도전재는 카본 블랙, 아세틸렌 블랙, 케첸 블랙과 같은 탄소계 물질; 또는 폴리아닐린, 폴리티오펜, 폴리아세틸렌, 폴리피롤과 같은 전도성 고분자일 수 있으며, 상기 도전재는 상기 양극활물질층 총 중량에 대하여 5 내지 20중량%로 포함되는 것이 바람직할 수 있다. 상기 도전재의 함량이 5중량% 미만이면 상기 도전재 사용에 따른 도전성 향상효과가 미미하고, 반면 20중량%를 초과하면 양극활물질의 함량이 상대적으로 적게 되어 용량 특성이 저하될 우려가 있다.The conductive material may be a carbon-based material such as carbon black, acetylene black, or ketjen black; Or it may be a conductive polymer such as polyaniline, polythiophene, polyacetylene, polypyrrole, the conductive material may be preferably contained in 5 to 20% by weight based on the total weight of the positive electrode active material layer. If the content of the conductive material is less than 5% by weight, the conductivity improvement effect according to the use of the conductive material is insignificant, whereas if the content of more than 20% by weight, the content of the positive electrode active material is relatively small, there is a fear that the capacity characteristics.
또, 상기 바인더로는 폴리(비닐 아세테이트), 폴리비닐알코올, 폴리에틸렌옥사이드, 폴리비닐피롤리돈, 알킬레이티드 폴리에틸렌옥사이드, 가교결합된 폴리에틸렌옥사이드, 폴리비닐에테르, 폴리(메틸메타크릴레이트), 폴리비닐리덴플루오라이드, 폴리헥사플루오로프로필렌과 폴리비닐리덴플루오라이드의 코폴리머(상품명: Kynar), 폴리(에틸아크릴레이트), 폴리테트라플루오로에틸렌, 폴리비닐클로라이드, 폴리아크릴로니트릴, 폴리비닐피리딘, 폴리스티렌, 이들의 유도체, 블랜드, 코폴리머 등이 사용될 수 있다. 또 상기 바인더는 상기 양극활물질층 총 중량에 대하여 5 내지 20중량%로 포함되는 것이 바람직할 수 있다. 상기 바인더의 함량이 5중량% 미만이면 상기 바인더 사용에 따른 양극활물질간 또는 양극활물질과 집전체간 결착력 개선효과가 미미하고, 반면 20중량%를 초과하면 상기 양극활물질의 함량이 상대적으로 적게 되어 용량 특성이 저하될 우려가 있다.The binder may be poly (vinyl acetate), polyvinyl alcohol, polyethylene oxide, polyvinylpyrrolidone, alkylated polyethylene oxide, crosslinked polyethylene oxide, polyvinyl ether, poly (methyl methacrylate), poly Vinylidene fluoride, copolymer of polyhexafluoropropylene and polyvinylidene fluoride (trade name: Kynar), poly (ethyl acrylate), polytetrafluoroethylene, polyvinylchloride, polyacrylonitrile, polyvinylpyridine , Polystyrene, derivatives thereof, blends, copolymers and the like can be used. In addition, the binder may be preferably contained in 5 to 20% by weight based on the total weight of the positive electrode active material layer. When the content of the binder is less than 5% by weight, the effect of improving the binding strength between the positive electrode active material or between the positive electrode active material and the current collector according to the use of the binder is insignificant, whereas when the content of the binder exceeds 20% by weight, the content of the positive electrode active material is relatively small. There is a risk of deterioration of characteristics.
상기와 같은 양극(120)은 통상의 방법에 따라 제조될 수 있으며, 구체적으로는 상기 양극활물질과 도전재 및 바인더를 유기용매 상에서 혼합하여 제조한 양극활물질층 형성용 조성물을, 상기 양극집전체 위에 도포한 후 건조 및 선택적으로 압연하여 제조될 수 있다.The positive electrode 120 as described above may be manufactured according to a conventional method, and specifically, a positive electrode active material layer forming composition prepared by mixing the positive electrode active material, the conductive material, and the binder on an organic solvent, on the positive electrode current collector. After application, it can be prepared by drying and optionally rolling.
이때 상기 유기용매로는 상기 양극활물질, 바인더 및 도전재를 균일하게 분산시킬 수 있으며, 쉽게 증발되는 것을 사용하는 것이 바람직하다. 구체적으로는 아세토니트릴, 메탄올, 에탄올, 테트라하이드로퓨란, 물, 이소프로필알코올 등을 들 수 있다. In this case, as the organic solvent, the cathode active material, the binder, and the conductive material may be uniformly dispersed, and it is preferable to use one that is easily evaporated. Specifically, acetonitrile, methanol, ethanol, tetrahydrofuran, water, isopropyl alcohol, etc. are mentioned.
한편, 상기 리튬 황 전지에 있어서, 상기 음극(150)은 음극활물질로서 리튬 이온을 가역적으로 인터칼레이션 또는 디인터칼레이션할 수 있는 물질, 리튬 이온과 반응하여 가역적으로 리튬 함유 화합물을 형성할 수 있는 물질, 리튬 금속 및 리튬 합금으로 이루어진 군에서 선택되는 것을 포함할 수 있다. On the other hand, in the lithium sulfur battery, the negative electrode 150 is a negative electrode active material, a material capable of reversibly intercalating or deintercalating lithium ions, and can react with lithium ions to form a reversible lithium-containing compound And a material selected from the group consisting of lithium metal and lithium alloy.
상기 리튬이온을 가역적으로 인터칼레이션/디인터칼레이션할 수 있는 물질로는 탄소 물질로서, 상기 리튬 황 전지에서 일반적으로 사용되는 탄소계 음극 활물질은 어떠한 것도 사용할 수 있으며, 구체적인 예로는 결정질 탄소, 비정질 탄소 또는 이들을 함께 사용할 수 있다. 또한, 상기 리튬 이온과 반응하여 가역적으로 리튬 함유 화합물을 형성할 수 있는 물질의 대표적인 예로는 산화 주석(SnO2), 티타늄 나이트레이트, 실리콘(Si) 등을 들 수 있으나 이에 한정되는 것은 아니다. 상기 리튬 금속의 합금은 구체적으로 리튬과 Si, Al, Sn, Pb, Zn, Bi, In, Mg, Ga, 또는 Cd의 금속과의 합금일 수 있다.As a material capable of reversibly intercalating / deintercalating the lithium ion, any carbon-based negative electrode active material generally used in the lithium sulfur battery may be used, and specific examples thereof include crystalline carbon, Amorphous carbons or these may be used together. In addition, a representative example of a material capable of reacting with lithium ions to reversibly form a lithium-containing compound may include, but is not limited to, tin oxide (SnO 2 ), titanium nitrate, silicon (Si), and the like. Specifically, the alloy of the lithium metal may be an alloy of lithium with a metal of Si, Al, Sn, Pb, Zn, Bi, In, Mg, Ga, or Cd.
또, 상기 음극(150)은 상기한 음극활물질과 함께 선택적으로 바인더를 더 포함할 수 있다. In addition, the negative electrode 150 may optionally further include a binder together with the negative electrode active material.
상기 바인더는 음극활물질의 페이스트화, 활물질간 상호 접착, 활물질과 집전체와의 접착, 활물질 팽창 및 수축에 대한 완충 효과 등의 역할을 한다. 구체적으로 상기 바인더는 앞서 설명한 바와 동일하다.The binder acts as a paste for the negative electrode active material, mutual adhesion between the active materials, adhesion between the active material and the current collector, and a buffering effect on the expansion and contraction of the active material. Specifically, the binder is the same as described above.
또, 상기 음극(150)은 상기한 음극활물질 및 바인더를 포함하는 음극활물질층(151)의 지지를 위한 음극집전체(152)를 더 포함할 수도 있다. In addition, the negative electrode 150 may further include a negative electrode current collector 152 for supporting the negative electrode active material layer 151 including the negative electrode active material and the binder.
상기 음극집전체(152)는 구체적으로 구리, 알루미늄, 스테인리스스틸, 티타늄, 은, 팔라듐, 니켈, 이들의 합금 및 이들의 조합으로 이루어진 군에서 선택되는 것일 수 있다. 상기 스테인리스스틸은 카본, 니켈, 티탄 또는 은으로 표면 처리될 수 있으며, 상기 합금으로는 알루미늄-카드뮴 합금이 사용될 수 있다. 그 외에도 소성 탄소, 도전재로 표면 처리된 비전도성 고분자, 또는 전도성 고분자 등이 사용될 수도 있다.The negative electrode current collector 152 may be specifically selected from the group consisting of copper, aluminum, stainless steel, titanium, silver, palladium, nickel, alloys thereof, and combinations thereof. The stainless steel may be surface treated with carbon, nickel, titanium, or silver, and an aluminum-cadmium alloy may be used as the alloy. In addition, calcined carbon, a nonconductive polymer surface-treated with a conductive material, or a conductive polymer may be used.
또, 상기 음극(150)은 리튬 금속의 박막일 수도 있다. In addition, the cathode 150 may be a thin film of lithium metal.
또, 상기 리튬 황 전지에 있어서, 상기 분리막(140)은 전극을 물리적으로 분리하는 기능을 갖는 물리적인 분리막으로서, 통상 리튬 황 전지에서 분리막으로 사용되는 것이라면 특별한 제한없이 사용가능하며, 특히 전해질의 이온 이동에 대하여 저저항이면서 전해질 함습 능력이 우수한 것이 바람직하다. 구체적으로는 다공성 고분자 필름, 예를 들어 에틸렌 단독중합체, 프로필렌 단독중합체, 에틸렌/부텐 공중합체, 에틸렌/헥센 공중합체 및 에틸렌/메타크릴레이트 공중합체 등과 같은 폴리올레핀계 고분자로 제조한 다공성 고분자 필름을 단독으로 또는 이들을 적층하여 사용할 수 있으며, 또는 통상적인 다공성 부직포, 예를 들어 고융점의 유리 섬유, 폴리에틸렌테레프탈레이트 섬유 등으로 된 부직포를 사용할 수 있으나, 이에 한정되는 것은 아니다.In addition, in the lithium sulfur battery, the separator 140 is a physical separator having a function of physically separating an electrode, and can be used without particular limitation as long as it is generally used as a separator in a lithium sulfur battery. It is desirable to have low resistance to migration and excellent electrolyte-moisture capability. Specifically, 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 may be used alone. It may be used as a lamination or or a conventional porous non-woven fabric, for example, a non-woven fabric made of glass fibers, polyethylene terephthalate fibers of high melting point, etc. may be used, but is not limited thereto.
상기 리튬 황 전지는 상기 분리막(140)에 침지되는 전해질을 더 포함할 수 있다. 상기 전해질은, 유기용매와 리튬염을 포함할 수 있다.The lithium sulfur battery may further include an electrolyte immersed in the separator 140. The electrolyte may include an organic solvent and a lithium salt.
상기 유기용매는 구체적으로, 아릴 화합물, 바이사이클릭 에테르, 비환형 카보네이트, 설폭사이드 화합물, 락톤 화합물, 케톤 화합물, 에스테르 화합물, 설페이트 화합물, 설파이트 화합물 등과 같은 극성 용매일 수 있다.Specifically, the organic solvent may be a polar solvent such as an aryl compound, bicyclic ether, acyclic carbonate, sulfoxide compound, lactone compound, ketone compound, ester compound, sulfate compound, sulfite compound and the like.
보다 구체적으로는 상기 유기용매는 1,2-디메톡시에탄, 1,2-디에톡시에탄, 1,2-디부톡시에탄, 디옥솔란(Dioxolane, DOL), 1,4-디옥산, 테트라하이드로푸란, 2-메틸테트라하이드로퓨란, 디메틸카보네이트(DMC), 디에틸카보네이트(DEC), 에틸메틸카보네이트(EMC), 메틸프로필카보네이트(MPC), 에틸프로필카보네이트, 디프로필카보네이트, 부틸에틸카보네이트, 에틸프로파노에이트(EP), 톨루엔, 자일렌, 디메틸에테르(dimethyl ether, DME), 디에틸에테르, 트리에틸렌글리콜모노메틸에테르(Triethylene glycol monomethyl ether, TEGME), 디글라임, 테트라글라임, 헥사메틸 포스포릭 트리아마이드(hexamethyl phosphoric triamide), 감마부티로락톤(GBL), 아세토니트릴, 프로피오니트릴, 에틸렌카보네이트(EC), 프로필렌카보네이트(PC), N-메틸피롤리돈, 3-메틸-2-옥사졸리돈, 아세트산에스테르, 부티르산에스테르 및 프로피온산에스테르, 디메틸포름아마이드, 설포란(SL), 메틸설포란, 디메틸아세트아마이드, 디메틸설폭사이드, 디메틸설페이트, 에틸렌글리콜 디아세테이트, 디메틸설파이트, 또는 에틸렌글리콜설파이트 등을 들 수 있다.More specifically, the organic solvent may be 1,2-dimethoxyethane, 1,2-diethoxyethane, 1,2-dibutoxyethane, dioxolane (Dioxolane, DOL), 1,4-dioxane, tetrahydrofuran , 2-methyltetrahydrofuran, dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), methyl propyl carbonate (MPC), ethyl propyl carbonate, dipropyl carbonate, butyl ethyl carbonate, ethyl propano EP, toluene, xylene, dimethyl ether (DME), diethyl ether, triethylene glycol monomethyl ether (TEGME), diglyme, tetraglyme, hexamethyl phosphoric tree Amide (hexamethyl phosphoric triamide), gamma butyrolactone (GBL), acetonitrile, propionitrile, ethylene carbonate (EC), propylene carbonate (PC), N-methylpyrrolidone, 3-methyl-2-oxazolidone To acetic acid esters, butyric acid And the like hotel and propionic acid esters, dimethyl formamide, sulfolane (SL), methyl sulfolane, dimethyl acetamide, dimethyl sulfoxide, dimethyl sulfate, ethylene glycol diacetate, dimethyl sulfite, or ethylene glycol sulfite.
이중에서도 트리에틸렌글리콜모노메틸에테르/디옥솔란/디메틸에테르의 혼합용매가 보다 바람직할 수 있다.Of these, a mixed solvent of triethylene glycol monomethyl ether / dioxolane / dimethyl ether may be more preferable.
또, 상기 리튬염은 리튬 이차 전지에서 사용되는 리튬 이온을 제공할 수 있는 화합물이라면 특별한 제한없이 사용할 수 있다. 구체적으로 상기 리튬염으로는 LiPF6, LiClO4, LiAsF6, LiBF4, LiSbF6, LiAl04, LiAlCl4, LiCF3SO3, LiC4F9SO3, LiN(C2F5SO3)2, LiN(C2F5SO2)2(Lithium bis(perfluoroethylsulfonyl)imide, BETI), LiN(CF3SO2)2(Lithium bis(Trifluoromethanesulfonyl)imide, LiTFSI), LiN(CaF2a+1SO2)(CbF2b+1SO2)(단, a 및 b는 자연수, 바람직하게는 1≤a≤20이고, 1≤b≤20임), 리튬 폴리[4,4'-(헥사플루오로이소프로필리덴)디페녹시]술포닐이미드(lithium poly[4,4'-(hexafluoroisopropylidene)diphenoxy]sulfonylimide, LiPHFIPSI), LiCl, LiI, LiB(C2O4)2 등이 사용될 수 있으며, 이중에서도 LiTFSI, BETI 또는 LiPHFIPSI 등과 같은 술포닐기-함유 이미드 리튬 화합물이 보다 바람직할 수 있다The lithium salt may be used without particular limitation as long as it is a compound capable of providing lithium ions used in a lithium secondary battery. Specifically, the lithium salt is LiPF 6 , LiClO 4 , LiAsF 6 , LiBF 4 , LiSbF 6 , LiAl0 4 , LiAlCl 4 , LiCF 3 SO 3 , LiC 4 F 9 SO 3 , LiN (C 2 F 5 SO 3 ) 2 LiN (C 2 F 5 SO 2 ) 2 (Lithium bis (perfluoroethylsulfonyl) imide, BETI), LiN (CF 3 SO 2 ) 2 (Lithium bis (Trifluoromethanesulfonyl) imide, LiTFSI), LiN (C a F 2a + 1 SO 2 ) (C b F 2b + 1 SO 2 ) (where a and b are natural numbers, preferably 1 ≦ a ≦ 20 and 1 ≦ b ≦ 20), lithium poly [4,4 ′-(hexafluoro Lysopropylidene) diphenoxy] sulfonylimide (lithium poly [4,4 '-(hexafluoroisopropylidene) diphenoxy] sulfonylimide, LiPHFIPSI), LiCl, LiI, LiB (C 2 O 4 ) 2, etc. may be used. Of these, sulfonyl group-containing imide lithium compounds such as LiTFSI, BETI or LiPHFIPSI may be more preferable.
또, 상기 리튬염은 상기 전해질 전체 중량에 대하여 10 내지 35중량%로 포함되는 것이 바람직할 수 있다. 상기 리튬염의 함량이 10중량% 미만이면 전해질의 전도도가 낮아져 전해질 성능이 저하되고, 35중량%를 초과하는 경우에는 전해질의 점도가 증가하여 리튬 이온의 이동성이 감소되는 문제점이 있다. In addition, the lithium salt may be preferably included in 10 to 35% by weight based on the total weight of the electrolyte. If the content of the lithium salt is less than 10% by weight, the conductivity of the electrolyte is lowered and the performance of the electrolyte is lowered. When the content of the lithium salt is more than 35% by weight, the viscosity of the electrolyte is increased to reduce the mobility of lithium ions.
한편, 상기 리튬 황 전지는 상기 분리막(140)과 상기 양극(120) 사이에 위치하는 겔 고분자 전해질(130)을 포함한다. 상기 겔 고분자 전해질(130)은 고분자 매트릭스에 상기 전해질이 지지된 것이다.Meanwhile, the lithium sulfur battery includes a gel polymer electrolyte 130 positioned between the separator 140 and the positive electrode 120. The gel polymer electrolyte 130 is supported by the electrolyte in a polymer matrix.
상기 고분자 매트릭스는, 특별히 한정되지는 않으나, 폴리에틸렌옥사이드계의 고분자 화합물, 폴리오르가노실록산 사슬 또는 폴리옥시알킬렌 사슬 등의 적어도 한종 이상을 포함한 고분자 수지를 사용할 수 있으며, 바람직하게는 트리메틸올프로판 에톡실레이트 트리아크릴레이트 단량체를 중합시켜 제조된 것일 수 있다. 상기 고분자 매트릭스로 상기 트리메틸올프로판 에톡실레이트 트리아크릴레이트 단량체의 중합체를 사용하는 경우 상기 고분자 매트릭스의 이온 해리 능력과 전해질의 함침 능력이 좋기 때문에 이온전도도를 향상시킬 수 있다.The polymer matrix is not particularly limited, but may be a polymer resin including at least one or more of a polyethylene oxide-based polymer compound, a polyorganosiloxane chain, or a polyoxyalkylene chain, preferably trimethylolpropane. It may be prepared by polymerizing the toxyl triacrylate monomer. When the polymer of the trimethylolpropane ethoxylate triacrylate monomer is used as the polymer matrix, the ion dissociation ability and the impregnation ability of the electrolyte of the polymer matrix are good, thereby improving ion conductivity.
상기 트리메틸올프로판 에톡실레이트 트리아크릴레이트는 중량평균분자량이 200 내지 1000g/mol일 수 있고, 바람직하게 300 내지 700g/mol일 수 있다. 상기 트리메틸올프로판 에톡실레이트 트리아크릴레이트의 중량평균분자량이 200g/mol 미만인 경우 이온전도도가 저하될 수 있고, 1000g/mol을 초과하는 경우 물리적 셔틀 억제 효과가 저하될 수 있다.The trimethylolpropane ethoxylate triacrylate may have a weight average molecular weight of 200 to 1000 g / mol, preferably 300 to 700 g / mol. When the weight average molecular weight of the trimethylolpropane ethoxylate triacrylate is less than 200g / mol may be reduced ionic conductivity, if it exceeds 1000g / mol physical inhibitory effect can be reduced.
상기 겔 고분자 전해질(130) 안에 지지되는 전해질은, 유기용매와 리튬염을 포함할 수 있다. 상기 유기용매와 리튬염에 대한 설명은 상기한 바와 동일하므로 반복된 설명은 생략한다.The electrolyte supported in the gel polymer electrolyte 130 may include an organic solvent and a lithium salt. Since the description of the organic solvent and the lithium salt is the same as described above, repeated description is omitted.
상기 전해질은 LiNO3를 추가로 포함한다. 상기 전해질이 상기 LiNO3를 포함하는 경우 셔틀 억제 효과를 향상시킬 수 있다. 상기 전해질은 상기 전해질 전체 중량에 대하여 상기 LiNO3를 1 내지 50중량%로 포함할 수 있고, 바람직하게 1.5 내지 10중량%로 포함할 수 있다. 상기 LiNO3의 함량이 1중량% 미만인 경우 셔틀 억제 효과가 나타나지 않을 수 있고, 50중량%를 초과하는 경우 LiNO3의 분해로 인한 부반응이 발생할 수 있다. 상기 겔 고분자 전해질(130)은 상기 고분자 매트릭스를 형성하는 상기 단량체, 상기 유기용매, 상기 리튬염 및 상기 LiNO3를 혼합하고, 상기 혼합물을 경화시켜 제조할 수 있다. 상기 경화는 열 경화 또는 광 경화일 수 있다. 이를 위하여 상기 혼합물에는 열 경화제 또는 광 경화제를 더 포함할 수 있다.The electrolyte further comprises LiNO 3 . When the electrolyte includes the LiNO 3 may improve the shuttle suppression effect. The electrolyte may include 1 to 50% by weight of LiNO 3 based on the total weight of the electrolyte, preferably 1.5 to 10% by weight. When the content of LiNO 3 is less than 1% by weight, the shuttle inhibitory effect may not appear, and when the content of LiNO 3 exceeds 50% by weight, side reactions due to decomposition of LiNO 3 may occur. The gel polymer electrolyte 130 may be prepared by mixing the monomer, the organic solvent, the lithium salt, and the LiNO 3 forming the polymer matrix, and curing the mixture. The curing may be thermal curing or photo curing. To this end, the mixture may further include a heat curing agent or a light curing agent.
상기 혼합물은 상기 유기용매와 상기 리튬염을 10:1 내지 1:1의 중량비로 포함할 수 있고, 바람직하게 4:1 내지 2:1의 중량비로 포함할 수 있다. 상기 유기용매의 중량비가 10:1 미만인 경우와 1:1을 초과하는 두 경우 모두에서 이온전도도가 저하될 수 있다.The mixture may include the organic solvent and the lithium salt in a weight ratio of 10: 1 to 1: 1, preferably in a weight ratio of 4: 1 to 2: 1. In both cases where the weight ratio of the organic solvent is less than 10: 1 and more than 1: 1, the ionic conductivity may be reduced.
상기 혼합물은 상기 리튬염을 포함하는 유기용매와 상기 단량체를 99:1 내지 10:90의 중량비로 포함할 수 있고, 바람직하게 95:5 내지 70:30의 중량비로 포함할 수 있다. 상기 단량체의 중량비가 99:1 미만인 경우 셔틀 억제 효과가 감소될 수 있고, 10:90을 초과하는 경우 이온전도도 감소로 인하여 전지 용량이 감소될 수 있다.The mixture may include the organic solvent including the lithium salt and the monomer in a weight ratio of 99: 1 to 10:90, preferably in a weight ratio of 95: 5 to 70:30. When the weight ratio of the monomer is less than 99: 1, the shuttle inhibitory effect may be reduced, and when it exceeds 10:90, the battery capacity may be reduced due to the decrease in ion conductivity.
상기 겔 고분자 전해질(130)은 상기 혼합물을 독립 필름으로 제조한 후 상기 분리막(140)과 상기 양극(120) 사이에 개재시킬 수 있고, 상기 혼합물을 상기 분리막(140) 또는 상기 양극(120) 위에 도포한 후 경화시켜 제조할 수도 있다.The gel polymer electrolyte 130 may be interposed between the separator 140 and the anode 120 after the mixture is prepared as an independent film, and the mixture may be disposed on the separator 140 or the anode 120. It may be prepared by curing after coating.
상기 혼합물을 상기 분리막(140) 또는 상기 양극(120) 위에 도포하는 방법은 특별히 한정되지 않으나, 스크린 프린팅법, 스프레이 코팅법, 닥터 블레이드를 이용한 코팅법, 그라비아 코팅법, 딥코팅법, 실크스크린법, 페인팅법, 슬릿다이를 이용한 코팅법, 스핀코팅법, 롤코팅법, 전사코팅법 등이 이용될 수 있다.The method of coating the mixture on the separator 140 or the anode 120 is not particularly limited, but the screen printing method, the spray coating method, the coating method using a doctor blade, the gravure coating method, the dip coating method, and the silk screen method , Painting, coating using a slit die, spin coating, roll coating, transfer coating method and the like can be used.
상기 경화는 열 경화 또는 광 경화일 수 있으며, 상기 열 경화의 경우 상기 경화는 60 내지 200℃에서 이루어질 수 있으며, 바람직하게 60 내지 150℃에서 이루어질 수 있다. 상기 경화 온도가 60℃ 미만인 경우 충분히 경화되지 않아 물리적인 셔틀 억제 효과가 감소될 수 있고, 150℃를 초과하는 경우 함침된 전해액의 휘발로 인하여 이온전도도 및 용량이 감소될 수 있다.The curing may be thermal curing or light curing, in the case of the thermal curing, the curing may be made at 60 to 200 ℃, preferably at 60 to 150 ℃. If the curing temperature is less than 60 ℃ may not be sufficiently cured to reduce the physical shuttle inhibitory effect, if it exceeds 150 ℃ may be reduced ionic conductivity and capacity due to volatilization of the impregnated electrolyte.
이하, 본 발명이 속하는 기술 분야에서 통상의 지식을 가진 자가 용이하게 실시할 수 있도록 본 발명의 실시예에 대하여 상세히 설명한다. 그러나 본 발명은 여러 가지 상이한 형태로 구현될 수 있으며 여기에서 설명하는 실시예에 한정되지 않는다.Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily practice the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.
[실시예: 겔 고분자 전해질 막의 제조 및 이를 적용한 전지의 제조][Example: Preparation of Gel Polymer Electrolyte Membrane and Fabrication of Battery]
(비교예 1)(Comparative Example 1)
황(평균입도: 40㎛)을 에탄올 중에서 Super P와 함께 볼밀을 사용하여 복합체를 먼저 제조하였다. 제조된 복합체와 도전재와 바인더와 믹서를 사용하여 믹싱하여 양극 활물질층 형성용 조성물을 제조하였다. 이때 도전재로는 카본블랙을, 바인더로는 SBR을 각각 사용하였으며, 혼합비율은 중량비로 복합체:도전재:바인더가 75:20:5가 되도록 하였다. 제조한 양극 활물질층 형성용 조성물을 알루미늄 집전체에 도포한 후 건조하여 양극을 제조하였다(양극의 에너지 밀도: 1.0mAh/㎠).Sulfur (average particle size: 40 μm) was first prepared using a ball mill with Super P in ethanol. The composite, conductive material, binder, and mixer were mixed to prepare a composition for forming a cathode active material layer. In this case, carbon black was used as the conductive material, and SBR was used as the binder, and the mixing ratio was 75: 20: 5 in the weight ratio of the composite: conductive material: binder. The prepared positive electrode active material layer-forming composition was applied to an aluminum current collector and then dried to prepare a positive electrode (energy density of positive electrode: 1.0 mAh / cm 2).
또한, 음극으로는 리튬 금속 박막을 준비하였다.In addition, a lithium metal thin film was prepared as a negative electrode.
유기용매 TEGDME/DOL/DME(1/1/1 vol.)에 리튬염으로 LiTFSI를 LiTFSI:유기용매=1:3의 중량비로 혼합한 전해질에 트리메틸올프로판 에톡실레이트 트리아크릴레이트 단량체를 유기용매:단량체=90:10의 중량비로 혼합한 겔 고분자 전해질 전구 물질을 광경화시켜 겔 고분자 전해질 막을 형성하였다.Trimethylolpropane ethoxylate triacrylate in an electrolyte prepared by mixing LiTFSI with a lithium salt in an organic solvent TEGDME / DOL / DME (1/1/1 vol.) In a weight ratio of LiTFSI: organic solvent = 1: 3. The gel polymer electrolyte precursor mixed with the monomers in a weight ratio of organic solvent: monomer = 90:10 was photocured to form a gel polymer electrolyte membrane.
상기 겔 고분자 전해질이 형성된 양극과 음극을 대면하도록 위치시킨 후, 폴리에틸렌의 분리막을 상기 양극과 음극 사이에 개재하였다.After the gel polymer electrolyte was formed to face the positive electrode and the negative electrode, a polyethylene separator was interposed between the positive electrode and the negative electrode.
그 후, 케이스 내부로 전해질을 주입하여 리튬 황 전지를 제조하였다. 이때상기 전해질은, 유기용매 TEGDME/DOL/DME(1/1/1 vol.)에 리튬염으로 LiTFSI를 LiTFSI:유기용매=1:3의 중량비로 혼합한 전해질을 사용하였다.Then, an electrolyte was injected into the case to prepare a lithium sulfur battery. At this time, the electrolyte was an electrolyte in which LiTFSI was mixed in an organic solvent TEGDME / DOL / DME (1/1/1 vol.) With a lithium salt in a weight ratio of LiTFSI: organic solvent = 1: 3.
(실시예 1)(Example 1)
황(평균입도: 40㎛)을 에탄올 중에서 Super P와 함께 볼밀을 사용하여 복합체를 먼저 제조하였다. 제조된 복합체와 도전재와 바인더와 믹서를 사용하여 믹싱하여 양극 활물질층 형성용 조성물을 제조하였다. 이때 도전재로는 카본블랙을, 바인더로는 SBR을 각각 사용하였으며, 혼합비율은 중량비로 복합체:도전재:바인더가 75:20:5가 되도록 하였다. 제조한 양극 활물질층 형성용 조성물을 알루미늄 집전체에 도포한 후 건조하여 양극을 제조하였다(양극의 에너지 밀도: 1.0mAh/㎠).Sulfur (average particle size: 40 μm) was first prepared using a ball mill with Super P in ethanol. The composite, conductive material, binder, and mixer were mixed to prepare a composition for forming a cathode active material layer. In this case, carbon black was used as the conductive material, and SBR was used as the binder, and the mixing ratio was 75: 20: 5 in the weight ratio of the composite: conductive material: binder. The prepared positive electrode active material layer-forming composition was applied to an aluminum current collector and then dried to prepare a positive electrode (energy density of positive electrode: 1.0 mAh / cm 2).
또한, 음극으로는 리튬 금속 박막을 준비하였다.In addition, a lithium metal thin film was prepared as a negative electrode.
유기용매 TEGDME/DOL/DME(1/1/1 vol.)에 리튬염으로 LiTFSI를 LiTFSI:유기용매=1:3의 중량비로 혼합하고, LiNO3를 LiTFSI의 1/10의 중량비로 첨가한 전해질에 트리메틸올프로판 에톡실레이트 트리아크릴레이트 단량체를 유기용매:단량체=90:10의 중량비로 혼합한 겔 고분자 전해질 전구물질을 상기 양극 표면에 코팅한 후 광경화시켜 겔 고분자 전해질을 형성하였다.LiTFSI was mixed in an organic solvent TEGDME / DOL / DME (1/1/1 vol.) With a lithium salt in a weight ratio of LiTFSI: organic solvent = 1: 3, and LiNO 3 was added in a weight ratio of 1/10 of LiTFSI. A gel polymer electrolyte precursor prepared by mixing trimethylolpropane ethoxylate triacrylate monomer in a weight ratio of organic solvent: monomer = 90: 10 was coated on the surface of the positive electrode and then photocured to form a gel polymer electrolyte.
상기 겔 고분자 전해질이 형성된 양극과 음극을 대면하도록 위치시킨 후, 폴리에틸렌의 분리막을 상기 양극과 음극 사이에 개재하였다.After the gel polymer electrolyte was formed to face the positive electrode and the negative electrode, a polyethylene separator was interposed between the positive electrode and the negative electrode.
그 후, 케이스 내부로 전해질을 주입하여 리튬 황 전지를 제조하였다. 이때상기 전해질은, 유기용매 TEGDME/DOL/DME(1/1/1 vol.)에 리튬염으로 LiTFSI를 LiTFSI:유기용매=1:3의 중량비로 혼합하고, LiNO3를 LiTFSI의 1/10의 중량비로 첨가한 전해질을 사용하였다.Then, an electrolyte was injected into the case to prepare a lithium sulfur battery. At this time, the electrolyte is mixed with organic solvent TEGDME / DOL / DME (1/1/1 vol.) With LiTFSI in a weight ratio of LiTFSI: organic solvent = 1: 3, and LiNO 3 is mixed with 1/10 of LiTFSI. An electrolyte added in weight ratio was used.
(실시예 2)(Example 2)
상기 실시예 1의 상기 겔 고분자 전해질 전구 물질에서 유기용매:단량체=85:15의 중량비로 변경한 것을 제외하고는 상기 실시예 1과 동일하게 실시하여 겔 고분자 전해질 막을 형성하였다.A gel polymer electrolyte membrane was formed in the same manner as in Example 1 except that the gel polymer electrolyte precursor of Example 1 was changed to a weight ratio of organic solvent: monomer = 85: 15.
(실시예 3)(Example 3)
상기 실시예 1의 상기 겔 고분자 전해질 전구 물질에서 유기용매:단량체=80:20의 중량비로 변경한 것을 제외하고는 상기 실시예 1과 동일하게 실시하여 겔 고분자 전해질 막을 형성하였다.A gel polymer electrolyte membrane was formed in the same manner as in Example 1 except that the gel polymer electrolyte precursor of Example 1 was changed to a weight ratio of organic solvent: monomer = 80: 20.
(실시예 4)(Example 4)
상기 실시예 1의 상기 겔 고분자 전해질 전구 물질에서 LiTFSI:유기용매=1:2의 중량비로 변경한 것을 제외하고는 상기 실시예 1과 동일하게 실시하여 겔 고분자 전해질 막을 형성하였다.The gel polymer electrolyte precursor of Example 1 was carried out in the same manner as in Example 1 except that the weight ratio of LiTFSI: organic solvent = 1: 2 was changed to the gel polymer electrolyte precursor. An electrolyte membrane was formed.
[실험예]Experimental Example
상기 실시예 1 내지 4에서 제조된 리튬 황 전지에서 제조된 전해질의 이온전도도를 SUS를 전극으로 한 코인셀을 제작하여 전기화학적 임피던스 분석법(Electrochemical Impedance Spectroscopy; EIS)에 의하여 측정하였고, 그 결과를 하기 표 1에 나타내었다.The ion conductivity of the electrolyte prepared in the lithium sulfur batteries prepared in Examples 1 to 4 was manufactured by using a coin cell using SUS as an electrode, and measured by electrochemical impedance spectroscopy (EIS), and the results were as follows. Table 1 shows.
유기용매:단량체 중량비Organic solvent: monomer weight ratio 리튬염:유기용매 중량비Lithium salt: Organic solvent weight ratio 이온전도도Ion conductivity
실시예 1Example 1 90:1090:10 1:31: 3 1.1×10-3S/cm1.1 × 10 -3 S / cm
실시예 2Example 2 85:1585:15 1:31: 3 4.1×10-4S/cm4.1 × 10 -4 S / cm
실시예 3Example 3 80:2080:20 1:31: 3 6.6×10-5S/cm6.6 × 10 -5 S / cm
실시예 4Example 4 85:1585:15 1:21: 2 1.8×10-4S/cm1.8 × 10 -4 S / cm
상기 표 1을 참고하면, 실시예 1에서 제조된 전해질의 이온전도도가 가장 우수한 것을 알 수 있다.Referring to Table 1, it can be seen that the ion conductivity of the electrolyte prepared in Example 1 is the most excellent.
또한, 상기 실시예 1 및 비교예 1에서 제조된 리튬 황 전지에 대하여 1.5-2.8V 전압 범위에서 0.1C 조건으로 충전 및 방전 실험을 수행하였다. 그 결과는 도2에 나타내었다. 도 2 내지 4는 각각 1 사이클, 2 사이클 및 12 사이클에서의 결과이다.In addition, charging and discharging experiments were performed on the lithium sulfur batteries prepared in Example 1 and Comparative Example 1 under 0.1C conditions in a voltage range of 1.5-2.8V. The results are shown in FIG. 2 to 4 show results at 1 cycle, 2 cycles and 12 cycles, respectively.
상기 도 2 내지 4를 참조하면, 본 발명의 겔 고분자 전해질을 적용한 리튬 황 전지가 셔틀 반응의 물리적 억제 효과로 인해 쿨롱 효율(Coulombic efficiency), 초기 방전 용량, 재현성(Cyclability) 등이 향상된 것을 알 수 있다.2 to 4, it can be seen that the lithium sulfur battery to which the gel polymer electrolyte of the present invention is applied has an improved coulombic efficiency, initial discharge capacity, reproducibility, etc. due to the physical inhibitory effect of the shuttle reaction. have.
본 발명은 셔틀 효과(shuttle effect)에 의한 퇴화가 방지된 리튬 황 전지 및 이의 제조 방법에 관한 것이다.The present invention relates to a lithium sulfur battery which is prevented from deterioration due to a shuttle effect and a method of manufacturing the same.
상기 리튬 황 전지는 폴리설파이드계 물질의 상기 음극으로의 이동을 억제하도록 구성된 겔 고분자 전해질을 포함하여, 충방전 반응시 양극 표면에 형성되는 폴리설파이드의 유실을 방지함으로써, 수명 특성이 향상된다The lithium sulfur battery includes a gel polymer electrolyte configured to suppress migration of a polysulfide-based material to the negative electrode, thereby preventing loss of polysulfide formed on the surface of the positive electrode during charge and discharge reaction, thereby improving lifespan characteristics.

Claims (8)

  1. 서로 대향 배치되는 양극과 음극, Positive and negative electrodes disposed opposite each other,
    상기 양극과 음극 사이에 위치하는 분리막, 그리고A separator located between the anode and the cathode, and
    상기 분리막과 양극 사이에 위치하는 겔 고분자 전해질을 포함하며,It comprises a gel polymer electrolyte positioned between the separator and the anode,
    상기 겔 고분자 전해질은 LiNO3를 포함하는 것인 리튬 황 전지.Wherein said gel polymer electrolyte comprises LiNO 3 .
  2. 제1항에 있어서,The method of claim 1,
    상기 겔 고분자 전해질이 상기 양극 표면 또는 상기 분리막 표면에 코팅되어 있는 것인 리튬 황 전지.And the gel polymer electrolyte is coated on the positive electrode surface or the separator surface.
  3. 제1항에 있어서,The method of claim 1,
    상기 겔 고분자 전해질은 고분자 매트릭스 및 상기 고분자 매트릭스에 지지된 유기용매와 리튬염을 포함하는 것인 리튬 황 전지.Wherein the gel polymer electrolyte comprises a polymer matrix, an organic solvent supported on the polymer matrix, and a lithium salt.
  4. 제3항에 있어서,The method of claim 3,
    상기 고분자 매트릭스는 트리메틸올프로판 에톡실레이트 트리아크릴레이트 단량체가 중합된 고분자인 것인 리튬 황 전지.The polymer matrix is a lithium sulfur battery that is a polymer polymerized with trimethylolpropane ethoxylate triacrylate monomer.
  5. 단량체, 유기용매, 리튬염 및 LiNO3를 혼합하고, A monomer, an organic solvent, a lithium salt and LiNO 3 are mixed,
    상기 혼합물을 양극 또는 분리막 위에 도포한 후 경화시켜, 상기 분리막과 양극 사이에 위치하는 겔 고분자 전해질을 제조하는 단계를 포함하는 리튬 황 전지 제조 방법.And applying the mixture on a cathode or a separator and curing the mixture to prepare a gel polymer electrolyte positioned between the separator and the anode.
  6. 제5항에 있어서,The method of claim 5,
    상기 단량체는 트리메틸올프로판 에톡실레이트 트리아크릴레이트인 것인 리튬 황 전지의 제조 방법.The monomer is a method for producing a lithium sulfur battery that is trimethylolpropane ethoxylate triacrylate.
  7. 제5항에 있어서,The method of claim 5,
    상기 용매는 TEGDME(Triethylene glycol dimethyl ether), DOL(Dioxolane), DME(Dimethoxyethane) 및 이들의 혼합 용액으로 이루어진 군에서 선택되는 어느 하나인 것인 리튬 황 전지의 제조 방법.The solvent is any one selected from the group consisting of TEGDME (Triethylene glycol dimethyl ether), DOL (Dioxolane), DME (Dimethoxyethane) and a mixed solution thereof.
  8. 제5항에 있어서,The method of claim 5,
    상기 리튬염은 LiTFSI(lithium bis-trifluoromethanesulfonimide)인 것인 리튬 황 전지의 제조 방법.The lithium salt is LiTFSI (lithium bis-trifluoromethanesulfonimide) is a method for producing a lithium sulfur battery.
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