WO2018216866A1 - Electrolyte solution for lithium-sulfur battery and lithium-sulfur battery comprising same - Google Patents

Electrolyte solution for lithium-sulfur battery and lithium-sulfur battery comprising same Download PDF

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WO2018216866A1
WO2018216866A1 PCT/KR2017/014351 KR2017014351W WO2018216866A1 WO 2018216866 A1 WO2018216866 A1 WO 2018216866A1 KR 2017014351 W KR2017014351 W KR 2017014351W WO 2018216866 A1 WO2018216866 A1 WO 2018216866A1
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group
lithium
carbon atoms
substituted
unsubstituted
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PCT/KR2017/014351
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French (fr)
Korean (ko)
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양승윤
양두경
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주식회사 엘지화학
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Priority claimed from KR1020170166320A external-priority patent/KR102183662B1/en
Application filed by 주식회사 엘지화학 filed Critical 주식회사 엘지화학
Priority to EP17910613.3A priority Critical patent/EP3547435A4/en
Priority to US16/469,308 priority patent/US11217824B2/en
Priority to JP2019532712A priority patent/JP6872100B2/en
Priority to CN201780083784.0A priority patent/CN110199426B/en
Publication of WO2018216866A1 publication Critical patent/WO2018216866A1/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
    • 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
    • H01M10/0568—Liquid materials characterised by the solutes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
    • H01M4/381—Alkaline or alkaline earth metals elements
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2300/00—Electrolytes
    • H01M2300/0085—Immobilising or gelification of electrolyte
    • 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 electrolyte and a lithium-sulfur battery including the same.
  • the lithium-sulfur battery uses a sulfur-based compound containing a sulfur-sulfur bond as a positive electrode active material, and a carbon-based material in which insertion / deintercalation of an alkali metal such as lithium or metal ions such as lithium ions occurs as a negative electrode active material. It is a secondary battery.
  • the theoretical discharge capacity of the lithium-sulfur battery is 1,675 mAh / g
  • the theoretical energy density is 2,600 Wh / kg, about 5 times higher theoretical energy density than the lithium ion battery (about 570 Wh / kg) currently being studied Since the battery has high capacity, high energy density and long life.
  • sulfur which is the main material of the positive electrode active material, has a low weight per atom, is rich in resources, easy to obtain, inexpensive, non-toxic, and environmentally friendly, so lithium-sulfur batteries are not only portable electronic devices but also electric vehicles. It is attracting attention as an energy source of medium and large devices such as.
  • the oxidation reaction of lithium occurs at the negative electrode of the lithium-sulfur battery, and the reduction reaction of sulfur occurs at the positive electrode.
  • Sulfur before discharging has a cyclic S 8 structure, in which the oxidation number of sulfur decreases as the sulfur-sulfur bond is broken during the reduction reaction (discharge), and the sulfur oxide number increases as the sulfur-sulfur bond is formed again during the oxidation reaction (charging). Redox reactions are used to store and generate electrical energy.
  • a reduction reaction in a cyclic S 8 lithium polysulfide is When fully reduced, lithium sulfide (Li 2 S) is finally formed.
  • Discharge behavior of the lithium-sulfur battery by the process of reduction to each lithium polysulfide shows a discharge voltage step by step unlike the lithium ion battery.
  • lithium polysulfides such as Li 2 S 8 , Li 2 S 6 , Li 2 S 4 , and Li 2 S 2 , which are intermediate products of the electrochemical reaction of a lithium-sulfur battery
  • lithium polysulfide having a high oxidation number of sulfur (Li 2 S x In general, x> 4) is a highly polar substance and easily soluble in an electrolyte solution containing a hydrophilic organic solvent. Lithium polysulfide dissolved in the electrolyte is diffused from the anode by the difference in concentration.
  • lithium polysulfide eluted from the positive electrode is out of the electrochemical reaction region of the positive electrode and thus it is impossible to phase-reduce it into lithium sulfide (Li 2 S).
  • lithium polysulfide which is present in the state dissolved out of the positive electrode and dissolved in the electrolyte solution, cannot participate in the charge / discharge reaction of the battery, so that sulfur used as the positive electrode active material is lost, leading to a major decrease in capacity and life of the lithium-sulfur battery. It becomes a factor.
  • the eluted lithium polysulfide reacts directly with the lithium metal negative electrode to fix the lithium sulfide on the lithium metal surface, thereby lowering the reaction activity resulting in poor potential characteristics and corrosion of the negative electrode. do.
  • an additive having a property of adsorbing sulfur is added to the positive electrode mixture or the electrolyte, or the surface of the positive electrode active material is treated with a material containing a specific functional group, or sulfur is supported on carbon material or metal oxide.
  • Various methods have been studied such as using a composite as a cathode active material.
  • Korean Patent Laid-Open Publication No. 2015-0032670 discloses that by including nitrogen-containing additives, sulfur-containing additives, or organic peroxides in an electrolyte, it is possible to suppress the dissolution of lithium polysulfide, thereby improving the battery performance reduction problem.
  • the Republic of Korea Patent Publication No. 2016-0046775 has a positive electrode coating layer made of an amphiphilic polymer on the surface of the positive electrode active portion including a sulfur-carbon composite to prevent lithium polysulfide from eluting into the electrolyte capacity of the battery And to improve cycle characteristics.
  • the present inventors conducted various studies to solve the above problems, and when the polymer containing an alkali metal ion is included as an additive in the lithium-sulfur battery electrolyte, the conductivity of lithium ions is improved, thereby improving the stability, performance and lifespan of the battery. It was confirmed that this improvement was completed the present invention.
  • an object of the present invention is to provide an electrolyte solution for lithium-sulfur batteries having excellent performance and lifespan characteristics.
  • Another object of the present invention is to provide a lithium-sulfur battery including the electrolyte.
  • the present invention comprises a lithium salt, an organic solvent and an additive, the additive provides an electrolyte solution for a lithium-sulfur battery comprising an ionomer of alkali metal salt type.
  • the alkali metal salt type ionomer may include at least one ionic group selected from the group consisting of a carboxylate group, a sulfonate group, a sulfonyl group, a sulfate group, a sulfinate group, a phosphate group, and a phosphonate group.
  • the alkali metal salt ionomer may be represented by the following Chemical Formula 1:
  • the alkali metal salt type ionomer may include one or more selected from the group consisting of lithium polyacrylate, lithium polymethacrylate, lithium polystyrene sulfonate, lithium polyacrylamidomethyl propane sulfonate and lithium polyvinyl sulfonate.
  • the number average molecular weight of the alkali metal salt ionomer may be 1,000 to 10,000.
  • the alkali metal salt type ionomer may be included in an amount of 0.1 to 0.5 wt% based on 100 wt% of the total electrolyte for lithium-sulfur batteries.
  • the present invention provides a lithium-sulfur battery including the electrolyte.
  • the electrolyte solution for a lithium-sulfur battery according to the present invention includes an ionomer containing an alkali metal salt as an additive, mobility characteristics of lithium ions may be improved, thereby improving capacity and lifespan characteristics of the lithium-sulfur battery.
  • Example 1 is a graph showing the life characteristics of a battery according to Experimental Example 1 of the present invention.
  • Lithium-sulfur batteries have a much higher theoretical energy density than conventional secondary batteries, and sulfur, which is used as a positive electrode active material, has been spotlighted as a next-generation battery due to its rich reserves, low cost, and environmental friendliness.
  • the lithium-sulfur battery loses sulfur as a positive electrode active material due to a shuttle phenomenon in which lithium polysulfide formed at the positive electrode is lost out of the positive electrode reaction region and moves between the positive electrode and the negative electrode during the charge / discharge reaction. This results in a decrease in capacity and lifetime.
  • a side reaction between the lithium polysulfide and the lithium metal eluted from the positive electrode causes a problem that the deterioration of efficiency and lifetime of the lithium metal electrode is accelerated.
  • the present invention provides a lithium-sulfur battery electrolyte including an polymer containing an alkali metal ion as an additive in order to secure the performance and lifespan improvement effect of the lithium-sulfur battery and improve the reaction stability of the battery.
  • the lithium-sulfur battery electrolyte according to the present invention includes a lithium salt, an organic solvent and an additive, and the additive includes an alkali metal salt type ionomer.
  • the ionomer is a polymer having ionic characteristics, a copolymer composed of nonpolar repeating units and ionic repeating units having no ionic covalent bonds, wherein the ionic repeating unit is contained within 15%, and the ionic repeating unit
  • the ionic group contained in is neutralized (or substituted) with metal ions.
  • the ionomer of the present invention means any polymer material in which metal ions are introduced into the main chain or the side chain of the polymer.
  • the ionic group of the ionomer may be partially neutralized or completely neutralized with alkali metal ions. For example, it may be neutralized by 50 to 100% based on the total ionic groups included in the ionomer.
  • the ionomer includes an acidic group as an ionic group, for example, polyacrylic acid (PAA), polymethacrylic acid (PMA), polystyrene sulfonic acid (Poly) (styrenesulfonic acid), PSSA), polyacryllamido-2-methyl-1-propanesulfonic acid (PAMPSA), polyvinyl sulfonic acid (PVSA), Nafion (Nafion) etc. are mentioned.
  • PAA polyacrylic acid
  • PMA polymethacrylic acid
  • PMA polystyrene sulfonic acid
  • PSSA polyacryllamido-2-methyl-1-propanesulfonic acid
  • PVSA polyvinyl sulfonic acid
  • Nafion Nafion
  • the ionic group is a carboxylate group, a sulfonate group and a phosphonate group, more preferably a carboxylate group.
  • the ionomer includes an ionic group as described above, some of which may be ionized in the electrolyte solution and substituted with an alkali metal, and thus the substituted form is referred to as an alkali metal salt ionomer.
  • the alkali metal salt ionomer of the present invention is represented by the following general formula (1):
  • R 1 to R 3 are the same as or different from each other, and each independently hydrogen; A substituted or unsubstituted alkyl group having 1 to 20 carbon atoms; A substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms; A substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms; Substituted or unsubstituted C2-C20 alkynyl group; Substituted or unsubstituted aryl group having 6 to 30 carbon atoms; Substituted or unsubstituted aryloxy group having 6 to 30 carbon atoms; A substituted or unsubstituted heteroaryl group having 6 to 30 carbon atoms; A substituted or unsubstituted heteroaryloxy group having 6 to 30 carbon atoms; A substituted or unsubstituted cycloalkyl group having 3 to 20 carbon atoms or a substituted or unsubstituted heterocycloalkyl
  • Y is at least one selected from the group consisting of carboxylate group, sulfonate group, sulfonyl group, sulfate group, sulfinate group, phosphate and phosphonate group,
  • M is an alkali metal
  • n is an integer from 100 to 1500).
  • alkyl group used in the present invention may be linear or branched chain, carbon number is not particularly limited but is preferably 1 to 20, specifically 1 to 10. Specific examples include, but are not limited to, methyl, ethyl, propyl, isopropyl, butyl, t-butyl, pentyl, hexyl, heptyl, and the like.
  • alkoxy group refers to an alkyl group having 1 to 20 carbon atoms including an oxygen radical unless otherwise stated, and is not limited thereto.
  • alkenyl group refers to a hydrocarbon group having 1 to 20 carbon atoms including at least one carbon-carbon double bond, unless otherwise specified, but is not limited thereto.
  • alkynyl group refers to a hydrocarbon group having 1 to 20 carbon atoms including at least one carbon-carbon triple bond, unless otherwise specified, but is not limited thereto.
  • cycloalkyl group means a non-aromatic carbon-based ring of at least three carbon atoms.
  • the cycloalkyl group includes, but is not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and the like, but is not limited thereto.
  • heterocycloalkyl group means a cycloalkyl group in which at least one carbon is replaced by a hetero atom.
  • the hetero atom means at least one selected from the group consisting of nitrogen (N), oxygen (O), sulfur (S), phosphorus (P), and silicon (Si).
  • aryl group refers to a single or multiple aromatic carbon-based ring having 6 to 30 carbon atoms.
  • aryl group refers to a single or multiple aromatic carbon-based ring having 6 to 30 carbon atoms.
  • aryloxy group refers to an aryl group having 6 to 30 carbon atoms including an oxygen radical, unless otherwise specified, and is not limited thereto.
  • heteroaryl group means an aryl group in which at least one carbon is replaced with a hetero atom, wherein the hetero atom is as described above.
  • heteroaryloxy group refers to an aryloxy group in which at least one carbon is replaced by a hetero atom, wherein the hetero atoms are as described above.
  • alkanediyl group refers to a divalent atomic group obtained by subtracting two hydrogen atoms from a straight or branched alkane, and may be represented by the general formula —C n H 2n ⁇ . .
  • alkenediyl group is a divalent atomic group obtained by subtracting two hydrogen atoms from a straight or branched chain alkene, and may be represented by the general formula -C n H n- . .
  • alkynediyl group is a divalent atomic group minus two hydrogen atoms in a straight or branched alkyne.
  • arylene group refers to a divalent aromatic carbon-based ring and may have 6 to 30 carbon atoms, specifically 6 to 20 carbon atoms.
  • the arylene group may include a structure in which two or more rings are condensed or bonded, and the other ring may be aromatic, non-aromatic, or a combination thereof.
  • the arylene group includes, but is not limited to, phenylene, biphenylene, naphthylene, anthracenylene, and the like.
  • heteroarylene group refers to an arylene group in which at least one carbon is replaced with a hetero atom, wherein the hetero atom is as described above.
  • alkali metal as used herein is lithium (Li), sodium (Na) or potassium (K).
  • substitutions are halogen, amino, nitrile, nitro, hydroxyl groups. Selected from the group consisting of carbonyl group, oxy group, carbonyloxy group, iminocarbonyl group, iminosulfonyl group, sulfanyl group, sulfinyl group, sulfonyl group, sulfonyloxy group, alkyl group, alkenyl group, alkynyl group, aryl group, heteroaryl group It is meant to be substituted with one or more substituents, which are not limited to these substituents.
  • R 1 to R 3 are preferably hydrogen; A substituted or unsubstituted alkyl group having 1 to 20 carbon atoms; It is a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms or a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, and more preferably hydrogen or a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms.
  • X is preferably a single bond; Or a substituted or unsubstituted alkanediyl group having 1 to 20 carbon atoms or a substituted or unsubstituted arylene group having 6 to 30 carbon atoms.
  • Y is an ionic group including an acidic group, preferably a carboxylate group, a sulfonate group or a phosphonate group, and more preferably a carboxylate group.
  • M is an alkali metal ion, preferably lithium ion.
  • n is an integer of 100 to 1500, preferably an integer of 150 to 500.
  • the ionomer of the alkali metal salt type represented by Chemical Formula 1 may significantly increase the ionic conductivity of the electrolyte even if only a small amount of the electrolyte is added in the molecule by including a large amount of lithium ions in the molecule.
  • the conventional method for increasing the lithium ion conductivity when the lithium salt concentration is increased, the viscosity of the electrolyte is increased, and the electrolyte salt may not have a sufficient effect due to the deterioration of the electrolyte salt and the occurrence of battery side reactions.
  • the concentration of lithium ions in the electrolyte can be increased without affecting other electrolytic salts or additives, which is caused by the progress of the cycle. It is also possible to compensate for the consumption of lithium ions due to the discharge process or electrolyte decomposition.
  • the alkali metal salt ionomer of the formula (1) is, for example, lithium polyacrylate (PALi), polymethyl methacrylate (PMALi), lithium polystyrene sulfonate (PSSLi), polyacrylamidomethyl propane sulfonate (PAMPSLi) and poly Lithium vinyl sulfonate (PVSLi) may include one or more selected from the group consisting of. Preferably it may be one or more selected from the group consisting of lithium polyacrylate, lithium polystyrene sulfonate and lithium polyvinyl sulfonate, and more preferably lithium polyacrylate.
  • PALi lithium polyacrylate
  • PMALi polymethyl methacrylate
  • PSSLi lithium polystyrene sulfonate
  • PAMPSLi polyacrylamidomethyl propane sulfonate
  • PVSLi poly Lithium vinyl sulfonate
  • PALi lithium polyacrylate
  • PMALi polymethyl meth
  • the number average molecular weight of the alkali metal salt type ionomer may be 1,000 to 10,000, preferably 1,500 to 5,000.
  • the number average molecular weight is less than the above range, the desired lithium ion conductivity improvement effect cannot be obtained, and when the number average molecular weight exceeds the above range, it is difficult to obtain a desired degree of substitution because it is difficult to produce an aqueous solution during the ion exchange process, and the viscosity of the electrolyte solution Is not only difficult to uniformly disperse, but may also cause problems such as deterioration of electrolyte solution or reduction of mobility of lithium ions.
  • the ionomer of the alkali metal salt type of the present invention can be prepared by neutralizing the polymer having the above-mentioned ionic group with a base compound containing an alkali metal, and at this time, a conventional method can be used as the neutralization method.
  • the base compound may be at least one selected from the group consisting of sodium hydroxide, sodium carbonate, lithium hydroxide and potassium hydroxide.
  • the alkali metal salt type ionomer may be included in an amount of 0.1 to 5 wt%, preferably 0.2 to 2 wt%, based on 100 wt% of the total electrolyte for lithium-sulfur batteries.
  • the content of the alkali metal salt ionomer is less than the above range, the effect of increasing lithium ion conductivity is insignificant.
  • the alkali ion exceeds the above range, an unnecessary reaction may occur when the battery is driven, thereby degrading the performance of the battery.
  • the electrolyte solution for lithium-sulfur batteries of the present invention includes lithium salts as electrolyte salts to increase ion conductivity.
  • the lithium salt is not particularly limited in the present invention, and may be used without limitation as long as it is commonly used in the art.
  • the lithium salt is LiCl, LiBr, LiI, LiClO 4 , LiBF 4 , LiB 10 Cl 10 , LiPF 6 , LiCF 3 SO 3 , LiCF 3 CO 2 , LiC 4 BO 8 , LiAsF 6 , LiSbF 6 , LiAlCl 4 , CH 3 SO 3 Li, CF 3 SO 3 Li, (CF 3 SO 2 ) 2 NLi, (C 2 F 5 SO 2 ) 2 NLi, (SO 2 F) 2 NLi, (CF 3 SO 2 ) 3 CLi It may include one or more selected from the group consisting of lithium chloroborane, lower aliphatic carboxylic acid having 4 or less carbon atoms, lithium 4-phenyl borate and lithium imide.
  • the lithium salt may be (SO 2 F) 2 NLi (lithium bis (fluorosulfonyl) imide, LiFSI).
  • the concentration of the lithium salt may be determined in consideration of ionic conductivity and the like, for example, 0.1 to 4.0 M, preferably 0.5 to 2.0 M.
  • concentration of the lithium salt is less than the above range, it is difficult to secure ionic conductivity suitable for driving the battery.On the contrary, when the concentration of the lithium salt exceeds the above range, the viscosity of the electrolyte increases to decrease the mobility of the lithium ions and the decomposition reaction of the lithium salt itself increases. Since the performance of the battery may be degraded, it is appropriately adjusted within the above range.
  • the electrolyte solution for lithium-sulfur batteries of the present invention includes an organic solvent, and those commonly used in lithium secondary battery electrolytes can be used without limitation, for example, ethers, esters, amides, linear carbonates, cyclic carbonates, and the like, respectively. Or it can mix and use 2 or more types.
  • the ether solvent may include acyclic ether and cyclic ether.
  • the acyclic ether is dimethyl ether, diethyl ether, dipropyl ether, methylethyl ether, methylpropyl ether, ethylpropyl ether, dimethoxyethane, diethoxyethane, methoxyethoxyethane, diethylene glycol dimethyl Ether, diethylene glycol diethyl ether, diethylene glycol methylethyl ether, triethylene glycol dimethyl ether, triethylene glycol diethyl ether, triethylene glycol methylethyl ether, tetraethylene glycol dimethyl ether, tetraethylene glycol diethyl ether, tetra One or more selected from the group consisting of ethylene glycol methylethyl ether, polyethylene glycol dimethyl ether, polyethylene glycol diethyl ether, polyethylene glycol methylethyl ether may be used, but is not limited thereto.
  • the cyclic ether is 1,3-dioxolane, 4,5-dimethyl-dioxolane, 4,5-diethyl-dioxolane, 4-methyl-1,3-dioxolane, 4- Ethyl-1,3-dioxolane, tetrahydrofuran, 2-methyl tetrahydrofuran, 2,5-dimethyl tetrahydrofuran, 2,5-dimethoxy tetrahydrofuran, 2-ethoxy tetrahydrofuran, 2- Methyl-1,3-dioxolane, 2-vinyl-1,3-dioxolane, 2,2-dimethyl-1,3-dioxolane, 2-methoxy-1,3-dioxolane, 2 -Ethyl-2-methyl-1,3-dioxolane, tetrahydropyrane, 1,4-dioxane, 1,2-dimethoxy benzen
  • ester solvent in the organic solvent examples include methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, ⁇ -butyrolactone, ⁇ -valerolactone, ⁇ -caprolactone, Any one or a mixture of two or more selected from the group consisting of ⁇ -valerolactone and ⁇ -caprolactone may be used, but is not limited thereto.
  • linear carbonate solvent examples include dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate, ethyl methyl carbonate (EMC), methylpropyl carbonate and ethylpropyl carbonate. Any one selected from the group consisting of, or a mixture of two or more thereof may be representatively used, but is not limited thereto.
  • cyclic carbonate solvent examples include ethylene carbonate (EC), propylene carbonate (PC), 1,2-butylene carbonate, 2,3-butylene carbonate, 1,2-pentylene Carbonate, 2,3-pentylene carbonate, vinylene carbonate, vinylethylene carbonate, and any one selected from the group consisting of halides thereof or mixtures of two or more thereof.
  • halides include, for example, fluoroethylene carbonate (FEC), but are not limited thereto.
  • the lithium secondary battery electrolyte of the present invention may further include an additive commonly used in the art in addition to the above-described composition.
  • an additive commonly used in the art for example, lithium nitrate (LiNO 3 ), potassium nitrate (KNO 3 ), cesium nitrate (CsNO 3 ), magnesium nitrate (MgNO 3 ), barium nitrate (BaNO 3 ), lithium nitrite (LiNO 2 ), potassium nitrite (KNO 2) ), Cesium nitrite (CsNO 2 ), and the like.
  • the present invention provides a lithium-sulfur battery comprising the electrolyte solution for lithium-sulfur batteries.
  • the lithium-sulfur battery includes a positive electrode, a negative electrode, and a separator and an electrolyte interposed between the positive electrode and the negative electrode, and uses the lithium-sulfur battery electrolyte according to the present invention as the electrolyte.
  • the positive electrode may include a positive electrode current collector and a positive electrode active material coated on one or both surfaces of the positive electrode current collector.
  • the positive electrode current collector supports the positive electrode active material, and is not particularly limited as long as it has high conductivity without causing chemical change in the battery.
  • copper, stainless steel, aluminum, nickel, titanium, palladium, calcined carbon, surface treated with carbon, nickel, silver, etc. on the surface of copper or stainless steel, aluminum-cadmium alloy, and the like can be used.
  • the positive electrode current collector may form fine concavities and convexities on its surface to enhance bonding strength with the positive electrode active material, and may be used in various forms such as a film, a sheet, a foil, a mesh, a net, a porous body, a foam, and a nonwoven fabric.
  • the cathode active material may include a cathode active material, and optionally a conductive material and a binder.
  • inorganic sulfur (S 8 ) can be used.
  • the positive electrode may further include one or more additives selected from transition metal elements, group IIIA elements, group IVA elements, sulfur compounds of these elements, and alloys of these elements and sulfur, in addition to the positive electrode active material.
  • the transition metal element may be Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Os, Ir, Pt, Au or Hg and the like
  • the Group IIIA element may include Al, Ga, In, Ti, and the like
  • the Group IVA element may include Ge, Sn, Pb and the like.
  • the conductive material is to improve electrical conductivity, and there is no particular limitation as long as it is an electronic conductive material that does not cause chemical change in a lithium secondary battery.
  • carbon black, graphite, carbon fiber, carbon nanotubes, metal powder, conductive metal oxide, organic conductive materials, and the like can be used, and currently commercially available as a conductive material acetylene black series (Chevron Chemical) Chevron Chemical Company or Gulf Oil Company, etc., Ketjen Black EC series (Armak Company), Vulcan XC-72 (Cabot Company) (Cabot Company) and Super P (MMM).
  • acetylene black, carbon black, graphite, etc. are mentioned.
  • the cathode active material may further include a binder having a function of maintaining the cathode active material in the cathode current collector and connecting the active material.
  • a binder for example, polyvinylidene fluoride-hexafulopropylene (PVDF-co-HFP), polyvinylidene fluoride (PVDF), polyacrylonitrile, poly
  • binders such as methyl methacrylate, styrene butadiene rubber (SBR), and carboxy methyl cellulose (CMC), may be used.
  • the negative electrode may include a negative electrode current collector and a negative electrode active material positioned on the negative electrode current collector.
  • the negative electrode may be a lithium metal plate.
  • the negative electrode current collector is for supporting the negative electrode active material, and is not particularly limited as long as it has excellent conductivity and is electrochemically stable in the voltage range of the lithium secondary battery.
  • copper, stainless steel, aluminum, nickel, titanium, Palladium, calcined carbon, surface treated with carbon, nickel, silver or the like on the surface of copper or stainless steel, aluminum-cadmium alloy, or the like may be used.
  • the negative electrode current collector may form fine irregularities on its surface to enhance bonding strength with the negative electrode active material, and may be used in various forms such as film, sheet, foil, mesh, net, porous body, foam, and nonwoven fabric.
  • the negative electrode active material includes a material capable of reversibly intercalating or deintercalating lithium (Li + ), a material capable of reacting with lithium ions to reversibly form a lithium-containing compound, a lithium metal or a lithium alloy can do.
  • the material capable of reversibly occluding or releasing the lithium ions (Li + ) may be, for example, crystalline carbon, amorphous carbon or a mixture thereof.
  • the material capable of reacting with the lithium ions (Li + ) to form a lithium-containing compound reversibly may be, for example, tin oxide, titanium nitrate or silicon.
  • the lithium alloy is, for example, lithium (Li) and sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), francium (Fr), beryllium (Be), magnesium (Mg), calcium ( It may be an alloy of a metal selected from the group consisting of Ca), strontium (Sr), barium (Ba), radium (Ra), aluminum (Al) and tin (Sn).
  • the negative electrode active material may be lithium metal, and specifically, may be in the form of a lithium metal thin film or lithium metal powder.
  • the method of forming the negative electrode active material is not particularly limited, and a method of forming a layer or a film commonly used in the art may be used. For example, a method such as pressing, coating or vapor deposition can be used.
  • the negative electrode of the present invention also includes a case where a metal lithium thin film is formed on a metal plate by initial charging after assembling a battery without a lithium thin film in a current collector.
  • the separator is used to physically separate both electrodes in the lithium-sulfur battery of the present invention. If the separator is used as a separator in a lithium-sulfur battery, the separator may be used without particular limitation. It is preferable that the electrolyte solution-wetting ability is excellent.
  • the separator may be made of a porous substrate, and the porous substrate may be used as long as it is a porous substrate commonly used in an electrochemical device.
  • a porous substrate commonly used in an electrochemical device.
  • a polyolefin-based porous membrane or a nonwoven fabric may be used, but is not particularly limited thereto. .
  • polyolefin-based porous membrane examples include polyethylene, polypropylene, polybutylene, polypentene, such as high density polyethylene, linear low density polyethylene, low density polyethylene, ultra high molecular weight polyethylene, respectively, or a mixture thereof
  • polyolefin-based polymers such as polyethylene, polypropylene, polybutylene, polypentene, such as high density polyethylene, linear low density polyethylene, low density polyethylene, ultra high molecular weight polyethylene, respectively, or a mixture thereof
  • polyethylene such as polyethylene, polypropylene, polybutylene, polypentene, such as high density polyethylene, linear low density polyethylene, low density polyethylene, ultra high molecular weight polyethylene, respectively, or a mixture thereof
  • polypentene such as high density polyethylene, linear low density polyethylene, low density polyethylene, ultra high molecular weight polyethylene, respectively, or a mixture thereof
  • the nonwoven fabric may be, for example, polyethylene terephthalate, polybutylene terephthalate, polyester, polyacetal, polyamide, polycarbonate, or polycarbonate. ), Polyimide, polyetheretherketone, polyethersulfone, polyphenyleneoxide, polyphenylenesulfide and polyethylenenaphthalate, respectively Or the nonwoven fabric formed from the polymer which mixed these is mentioned.
  • the structure of the nonwoven fabric may be a spunbond nonwoven fabric or a melt blown nonwoven fabric composed of long fibers.
  • the thickness of the porous substrate is not particularly limited, but may be 1 to 100 ⁇ m, preferably 5 to 50 ⁇ m.
  • the pore size and pore present in the porous substrate are also not particularly limited, but may be 0.001 to 50 ⁇ m and 10 to 95%, respectively.
  • the electrolyte solution includes lithium ions, and is used for causing an electrochemical oxidation or reduction reaction at the anode and the cathode through the media, as described above.
  • the injection of the electrolyte may be performed at an appropriate step in the manufacturing process of the electrochemical device, depending on the manufacturing process and the required physical properties of the final product. That is, it may be applied before the electrochemical device assembly or the final step of the electrochemical device assembly.
  • Lithium-sulfur battery according to the present invention is capable of lamination (stacking) and folding (folding) of the separator and the electrode, in addition to the general winding (winding).
  • the shape of the lithium-sulfur battery is not particularly limited and may be in various shapes such as cylindrical, stacked, and coin type.
  • the present invention provides a battery module including the lithium-sulfur battery as a unit cell.
  • the battery module may be used as a power source for medium and large devices requiring high temperature stability, long cycle characteristics, and high capacity characteristics.
  • Examples of the medium-to-large device include a power tool that is driven by an electric motor; Electric vehicles including electric vehicles (EVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and the like; Electric motorcycles including electric bicycles (E-bikes) and electric scooters (E-scooters); Electric golf carts; Power storage systems and the like, but is not limited thereto.
  • Electric vehicles including electric vehicles (EVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and the like
  • Electric motorcycles including electric bicycles (E-bikes) and electric scooters (E-scooters); Electric golf carts; Power storage systems and the like, but is not limited thereto.
  • Sulfur was mixed in acetonitrile using a conductive material, a binder, and a ball mill to prepare a positive electrode active material slurry.
  • carbon black was used as the conductive material and polyethylene oxide (molecular weight 5,000,000 g / mol) was used as the binder, and the mixing ratio was set to be 90: 5: 5 by weight ratio of sulfur: conductive material: binder.
  • the positive electrode active material slurry was applied to an aluminum current collector and then dried to prepare a positive electrode.
  • a lithium metal thin film having a thickness of 40 ⁇ m was used as the negative electrode.
  • the positive electrode and the negative electrode were placed to face each other, and a polyethylene separator was disposed therebetween, and the electrolyte solution prepared in Examples and Comparative Examples was injected to prepare a coin-type battery.
  • Comparative Example 1 which does not include an additive, the capacity drops sharply before 60 cycles, and in Comparative Examples 2 and 3 using the existing monomolecular compound, the irreversible capacity is maintained up to 80 cycles.
  • the electrolyte solution of Examples 1 and 2 according to the present invention was included, it was confirmed that the retention rate of the specific discharge capacity was stably maintained up to 110 cycles. Through this, in the case of the electrolyte according to the present invention, it is easy to transfer lithium ions and confirm that the depletion of lithium ions is delayed.
  • the electrolyte solution for lithium-sulfur batteries according to the present invention includes a polymer containing alkali metal ions as an additive to improve the mobility of lithium ions, thereby enabling high capacity, high stability, and long life of the lithium-sulfur battery.

Abstract

The present invention relates to an electrolyte solution for a lithium-sulfur battery and a lithium-sulfur battery comprising same and, more specifically, to an electrolyte solution, for a lithium-sulfur battery, comprising lithium salts, an organic solvent and an additive, wherein the additive comprises alkali metal salt type ionomer. The electrolyte solution for a lithium-sulfur battery comprises polymer which comprises an alkali metal ion as an additive and thus enables the transfer property of a lithium ion to be improved and the capacity and lifetime characteristics of the lithium-sulfur battery to be enhanced.

Description

리튬-황 전지용 전해액 및 이를 포함하는 리튬-황 전지Electrolyte for lithium-sulfur battery and lithium-sulfur battery comprising same
본 출원은 2017년 5월 26일자 한국 특허 출원 제10-2017-0065508호 및 2017년 12월 6일자 한국 특허 출원 제10-2017-0166320호에 기초한 우선권의 이익을 주장하며, 해당 한국 특허 출원의 문헌에 개시된 모든 내용은 본 명세서의 일부로서 포함한다.This application claims the benefit of priority based on Korean Patent Application No. 10-2017-0065508 filed May 26, 2017 and Korean Patent Application No. 10-2017-0166320 filed December 6, 2017. All content disclosed in the literature is included as part of this specification.
본 발명은 리튬-황 전지용 전해액 및 이를 포함하는 리튬-황 전지에 관한 것이다.The present invention relates to a lithium-sulfur battery electrolyte and a lithium-sulfur battery including the same.
최근 전자기기, 통신기기의 소형화, 경량화 및 고성능화가 급속히 진행되고 있으며, 환경 문제와 관련하여 전기 자동차의 필요성이 크게 대두됨에 따라 이들 제품의 에너지원으로 사용할 수 있는 이차전지의 성능 개선이 크게 요구되고 있다. 이러한 요구를 만족시키는 이차전지로 양극 활물질로 황계 물질을 사용하는 리튬-황 전지에 대한 많은 연구가 진행되고 있다.Recently, miniaturization, light weight, and high performance of electronic devices and communication devices are rapidly progressing, and as the necessity of electric vehicles increases in relation to environmental problems, the performance improvement of secondary batteries that can be used as energy sources of these products is greatly required. have. Much research has been conducted on lithium-sulfur batteries using a sulfur-based material as a cathode active material as a secondary battery that satisfies these requirements.
리튬-황 전지는 황-황 결합을 포함하는 황 계열 화합물을 양극 활물질로 사용하고, 리튬과 같은 알칼리 금속 또는 리튬 이온 등과 같은 금속 이온의 삽입/탈삽입이 일어나는 탄소계 물질을 음극 활물질로 사용하는 이차전지이다.The lithium-sulfur battery uses a sulfur-based compound containing a sulfur-sulfur bond as a positive electrode active material, and a carbon-based material in which insertion / deintercalation of an alkali metal such as lithium or metal ions such as lithium ions occurs as a negative electrode active material. It is a secondary battery.
특히, 리튬-황 전지의 이론 방전용량은 1,675mAh/g이며, 이론 에너지 밀도가 2,600Wh/kg로서, 현재 연구되고 있는 리튬이온전지(약 570Wh/kg)에 비해 약 5배 정도 높은 이론 에너지 밀도를 가지기 때문에 고용량, 고에너지 밀도 및 장수명의 구현이 가능한 전지이다. 또한, 양극 활물질의 주재료인 황은 낮은 원자당 무게를 가지며, 자원이 풍부하여 수급이 용이하며 값이 저렴하고, 독성이 없으며, 환경친화적 물질이라는 이점 때문에 리튬-황 전지는 휴대용 전자기기뿐만 아니라 전기 자동차와 같은 중대형 장치의 에너지원으로 주목을 받고 있다.In particular, the theoretical discharge capacity of the lithium-sulfur battery is 1,675 mAh / g, the theoretical energy density is 2,600 Wh / kg, about 5 times higher theoretical energy density than the lithium ion battery (about 570 Wh / kg) currently being studied Since the battery has high capacity, high energy density and long life. In addition, sulfur, which is the main material of the positive electrode active material, has a low weight per atom, is rich in resources, easy to obtain, inexpensive, non-toxic, and environmentally friendly, so lithium-sulfur batteries are not only portable electronic devices but also electric vehicles. It is attracting attention as an energy source of medium and large devices such as.
구체적으로, 리튬-황 전지의 음극(negative electrode)에서는 리튬의 산화 반응이 발생하고, 양극(positive electrode)에서는 황의 환원 반응이 발생한다. 방전 전의 황은 환형의 S8 구조를 가지고 있는데, 환원 반응(방전)시 황-황 결합이 끊어지면서 황의 산화수가 감소하고, 산화 반응(충전)시 황-황 결합이 다시 형성되면서 황의 산화수가 증가하는 산화-환원 반응을 이용하여 전기 에너지를 저장 및 생성한다. 이러한 전기화학 반응 중 황은 환형의 S8에서 환원 반응에 의해 선형 구조의 리튬 폴리설파이드(lithium polysulfide, Li2Sx, x = 8, 6, 4, 2)로 변환되게 되며, 이러한 리튬 폴리설파이드가 완전히 환원되면 최종적으로 리튬 설파이드(lithium sulfide, Li2S)가 생성되게 된다. 각각의 리튬 폴리설파이드로 환원되는 과정에 의해 리튬-황 전지의 방전 거동은 리튬 이온전지와는 달리 단계적으로 방전 전압을 나타낸다.Specifically, the oxidation reaction of lithium occurs at the negative electrode of the lithium-sulfur battery, and the reduction reaction of sulfur occurs at the positive electrode. Sulfur before discharging has a cyclic S 8 structure, in which the oxidation number of sulfur decreases as the sulfur-sulfur bond is broken during the reduction reaction (discharge), and the sulfur oxide number increases as the sulfur-sulfur bond is formed again during the oxidation reaction (charging). Redox reactions are used to store and generate electrical energy. During this electrochemical reaction, sulfur is converted into lithium polysulfide (lithium polysulfide, Li 2 S x , x = 8, 6, 4, 2) by a reduction reaction in a cyclic S 8 , and the lithium polysulfide is When fully reduced, lithium sulfide (Li 2 S) is finally formed. Discharge behavior of the lithium-sulfur battery by the process of reduction to each lithium polysulfide shows a discharge voltage step by step unlike the lithium ion battery.
리튬-황 전지의 전기화학 반응의 중간 생성물인 Li2S8, Li2S6, Li2S4, Li2S2 등의 리튬 폴리설파이드 중에서, 황의 산화수가 높은 리튬 폴리설파이드(Li2Sx, 보통 x > 4)는 극성이 강한 물질로 친수성 유기 용매를 포함하는 전해액에 쉽게 녹는다. 전해액에 녹은 리튬 폴리설파이드는 농도 차이에 의해서 양극으로부터 확산되어 간다. 이렇게 양극으로부터 용출된 리튬 폴리설파이드는 양극의 전기화학 반응 영역을 벗어나게 되어 리튬 설파이드(Li2S)로의 단계적 환원이 불가능하다. 즉, 양극을 벗어나 전해액에 용해된 상태로 존재하는 리튬 폴리설파이드는 전지의 충·방전 반응에 참여할 수 없게 되므로, 양극 활물질로 사용되는 황이 손실되고, 리튬-황 전지의 용량 및 수명 저하를 일으키는 주요한 요인이 된다.Among lithium polysulfides such as Li 2 S 8 , Li 2 S 6 , Li 2 S 4 , and Li 2 S 2 , which are intermediate products of the electrochemical reaction of a lithium-sulfur battery, lithium polysulfide having a high oxidation number of sulfur (Li 2 S x In general, x> 4) is a highly polar substance and easily soluble in an electrolyte solution containing a hydrophilic organic solvent. Lithium polysulfide dissolved in the electrolyte is diffused from the anode by the difference in concentration. The lithium polysulfide eluted from the positive electrode is out of the electrochemical reaction region of the positive electrode and thus it is impossible to phase-reduce it into lithium sulfide (Li 2 S). In other words, lithium polysulfide, which is present in the state dissolved out of the positive electrode and dissolved in the electrolyte solution, cannot participate in the charge / discharge reaction of the battery, so that sulfur used as the positive electrode active material is lost, leading to a major decrease in capacity and life of the lithium-sulfur battery. It becomes a factor.
또한, 용출된 리튬 폴리설파이드는 전해액 상에 부유 또는 침전되는 것 이외에도 리튬 금속 음극과 직접 반응하여 리튬 금속 표면에 리튬 설파이드가 고착됨으로 인해 반응 활성도가 낮아져 전위 특성이 나빠지며 음극을 부식시키는 문제가 발생한다.Further, in addition to being suspended or precipitated on the electrolyte, the eluted lithium polysulfide reacts directly with the lithium metal negative electrode to fix the lithium sulfide on the lithium metal surface, thereby lowering the reaction activity resulting in poor potential characteristics and corrosion of the negative electrode. do.
이러한 리튬 폴리설파이드의 용출을 최소화하기 위하여 황을 흡착하는 성질을 지니는 첨가제를 양극 합제 또는 전해질에 첨가하거나 양극 활물질 표면을 특정 작용기를 포함하는 물질로 표면 처리하거나 탄소재나 금속 산화물에 황을 담지한 복합체를 양극 활물질로 사용하는 등 다양한 방법들이 연구되고 있다.In order to minimize the dissolution of lithium polysulfide, an additive having a property of adsorbing sulfur is added to the positive electrode mixture or the electrolyte, or the surface of the positive electrode active material is treated with a material containing a specific functional group, or sulfur is supported on carbon material or metal oxide. Various methods have been studied such as using a composite as a cathode active material.
일례로, 대한민국 공개특허 제2015-0032670호는 전해질에 질소 함유 첨가제, 황 함유 첨가제 또는 유기 과산화물을 포함함으로써 리튬 폴리설파이드의 용출을 억제하여 전지 성능 감소 문제를 개선할 수 있음을 개시하고 있다.For example, Korean Patent Laid-Open Publication No. 2015-0032670 discloses that by including nitrogen-containing additives, sulfur-containing additives, or organic peroxides in an electrolyte, it is possible to suppress the dissolution of lithium polysulfide, thereby improving the battery performance reduction problem.
또한, 대한민국 공개특허 제 제2016-0046775호는 황-탄소 복합체를 포함하는 양극 활성부의 표면에 양친매성 고분자로 이루어진 양극 코팅층을 구비하여 리튬 폴리설파이드가 전해질로 용출되는 것을 차단함을 통해 전지의 용량 및 사이클 특 성을 개선할 수 있음을 개시하고 있다.In addition, the Republic of Korea Patent Publication No. 2016-0046775 has a positive electrode coating layer made of an amphiphilic polymer on the surface of the positive electrode active portion including a sulfur-carbon composite to prevent lithium polysulfide from eluting into the electrolyte capacity of the battery And to improve cycle characteristics.
이들 특허들은 첨가제나 코팅층을 통해 리튬 폴리설파이드의 용출을 어느 정도 억제하였으나 그 효과가 충분치 않다. 또한, 첨가제를 사용하는 경우 전기전도성 열화 또는 전지 부반응 촉진 문제를 야기하며, 코팅층을 형성하는 경우 표면 처리 과정에서 황이 유실되며 많은 시간과 비용이 소요되는 단점이 있다. 따라서, 리튬-황 전지에서 리튬 폴리설파이드 용출로 인한 리튬-황 전지의 용량 및 수명 저하를 효과적으로 억제할 수 있는 리튬-황 전지에 관한 개발이 더욱 필요한 실정이다.These patents suppressed the dissolution of lithium polysulfide to some extent through additives or coating layers, but the effect is insufficient. In addition, the use of additives causes problems of electrical conductivity degradation or battery side reaction promotion, and in the case of forming a coating layer, sulfur is lost during the surface treatment process and takes a lot of time and cost. Therefore, there is a further need for development of a lithium-sulfur battery that can effectively suppress the capacity and life deterioration of a lithium-sulfur battery due to lithium polysulfide elution in a lithium-sulfur battery.
[선행기술문헌][Preceding technical literature]
[특허문헌][Patent Documents]
대한민국 공개특허 제2015-0032670호(2015.03.27), 전해질 첨가제 및 이오노머 물품을 포함하는 전기화학 전지와 그의 제조 및 사용 방법Korean Unexamined Patent Publication No. 2015-0032670 (2015.03.27), an electrochemical cell comprising an electrolyte additive and an ionomer article and a method of manufacturing and using the same
대한민국 공개특허 제2016-0046775호(2016.04.29), 리튬-황 전지용 양극 및 이의 제조방법Republic of Korea Patent Publication No. 2016-0046775 (2016.04.29), a positive electrode for a lithium-sulfur battery and a manufacturing method thereof
이에 본 발명자들은 상기 문제를 해결하고자 다각적으로 연구를 수행한 결과, 리튬-황 전지용 전해액에 알칼리 금속 이온을 포함하는 고분자를 첨가제로 포함하는 경우 리튬 이온의 전도도가 개선되어 전지의 안정성, 성능 및 수명이 향상됨을 확인하여 본 발명을 완성하였다.Accordingly, the present inventors conducted various studies to solve the above problems, and when the polymer containing an alkali metal ion is included as an additive in the lithium-sulfur battery electrolyte, the conductivity of lithium ions is improved, thereby improving the stability, performance and lifespan of the battery. It was confirmed that this improvement was completed the present invention.
따라서, 본 발명의 목적은 성능과 수명 특성이 우수한 리튬-황 전지용 전해액을 제공하는데 있다.Accordingly, an object of the present invention is to provide an electrolyte solution for lithium-sulfur batteries having excellent performance and lifespan characteristics.
또한, 본 발명의 다른 목적은 상기 전해액을 포함하는 리튬-황 전지를 제공하는 것이다.In addition, another object of the present invention is to provide a lithium-sulfur battery including the electrolyte.
상기 목적을 달성하기 위해, 본 발명은 리튬염, 유기용매 및 첨가제를 포함하고, 상기 첨가제는 알칼리 금속염형의 이오노머를 포함하는 리튬-황 전지용 전해액을 제공한다.In order to achieve the above object, the present invention comprises a lithium salt, an organic solvent and an additive, the additive provides an electrolyte solution for a lithium-sulfur battery comprising an ionomer of alkali metal salt type.
상기 알칼리 금속염형의 이오노머는 카르복실레이트기, 설포네이트기, 설포닐기, 설페이트기, 설피네이트기, 포스페이트기 및 포스포네이트기로 이루어진 군에서 선택되는 1종 이상의 이온성기를 포함할 수 있다.The alkali metal salt type ionomer may include at least one ionic group selected from the group consisting of a carboxylate group, a sulfonate group, a sulfonyl group, a sulfate group, a sulfinate group, a phosphate group, and a phosphonate group.
상기 알칼리 금속염형의 이오노머는 하기 화학식 1로 표시될 수 있다:The alkali metal salt ionomer may be represented by the following Chemical Formula 1:
[화학식 1][Formula 1]
Figure PCTKR2017014351-appb-I000001
Figure PCTKR2017014351-appb-I000001
(상기 화학식 1에서, R1 내지 R3, X, Y, M 및 n은 명세서 내에서 설명한 바를 따른다.).(In Formula 1, R 1 to R 3 , X, Y, M and n are as described in the specification.).
상기 알칼리 금속염형의 이오노머는 폴리아크릴산리튬, 폴리메타크릴산리튬, 폴리스티렌술폰산리튬, 폴리아크릴아미도메틸프로판술폰산리튬 및 폴리비닐술폰산 리튬으로 이루어진 군에서 선택되는 1종 이상을 포함할 수 있다.The alkali metal salt type ionomer may include one or more selected from the group consisting of lithium polyacrylate, lithium polymethacrylate, lithium polystyrene sulfonate, lithium polyacrylamidomethyl propane sulfonate and lithium polyvinyl sulfonate.
상기 알칼리 금속염형의 이오노머의 수평균 분자량은 1,000 내지 10,000일 수 있다.The number average molecular weight of the alkali metal salt ionomer may be 1,000 to 10,000.
상기 알칼리 금속염형의 이오노머는 리튬-황 전지용 전해액 전체 100 중량%를 기준으로 0.1 내지 0.5 중량%로 포함될 수 있다.The alkali metal salt type ionomer may be included in an amount of 0.1 to 0.5 wt% based on 100 wt% of the total electrolyte for lithium-sulfur batteries.
아울러, 본 발명은 상기 전해액을 포함하는 리튬-황 전지를 제공한다.In addition, the present invention provides a lithium-sulfur battery including the electrolyte.
본 발명에 따른 리튬-황 전지용 전해액은 알칼리 금속염을 포함하는 이오노머를 첨가제로 포함하는 경우 리튬 이온의 이동 특성이 개선되어 리튬-황 전지의 용량 및 수명 특성을 향상시킬 수 있다.When the electrolyte solution for a lithium-sulfur battery according to the present invention includes an ionomer containing an alkali metal salt as an additive, mobility characteristics of lithium ions may be improved, thereby improving capacity and lifespan characteristics of the lithium-sulfur battery.
도 1은 본 발명의 실험예 1에 따른 전지의 수명 특성 나타내는 그래프이다.1 is a graph showing the life characteristics of a battery according to Experimental Example 1 of the present invention.
이하, 본 발명을 더욱 상세히 설명한다.Hereinafter, the present invention will be described in more detail.
본 명세서 및 청구범위에 사용된 용어나 단어는 통상적이거나 사전적인 의미로 한정해서 해석되어서는 아니되며, 발명자는 그 자신의 발명을 가장 최선의 방법으로 설명하기 위해 용어의 개념을 적절하게 정의할 수 있다는 원칙에 입각하여 본 발명의 기술적 사상에 부합하는 의미와 개념으로 해석되어야만 한다.The terms or words used in this specification and claims are not to be construed as being limited to their ordinary or dictionary meanings, and the inventors may appropriately define the concept of terms in order to best describe their invention. It should be interpreted as meaning and concept corresponding to the technical idea of the present invention based on the principle that the present invention.
리튬-황 전지는 기존 이차 전지에 비해 월등히 높은 이론 에너지 밀도를 가지며, 양극 활물질로 사용되는 황은 매장량이 풍부하여 저가이고, 환경친화적이라는 장점으로 인해 차세대 전지로 각광받고 있다.Lithium-sulfur batteries have a much higher theoretical energy density than conventional secondary batteries, and sulfur, which is used as a positive electrode active material, has been spotlighted as a next-generation battery due to its rich reserves, low cost, and environmental friendliness.
이러한 장점에도 불구하고 전술한 바와 같이 리튬-황 전지는 충·방전 반응시 양극에서 형성된 리튬 폴리설파이드가 양극 반응 영역 밖으로 유실되어 양극과 음극 사이를 이동하는 셔틀 현상으로 인해 양극 활물질인 황이 손실되어 전지의 용량 및 수명 감소를 초래하게 된다. 또한, 양극으로부터 용출된 리튬 폴리설파이드와 리튬 금속 사이의 부반응으로 인해 리튬 금속 전극의 효율과 수명의 저하가 가속화되는 문제가 발생한다.Despite these advantages, the lithium-sulfur battery, as described above, loses sulfur as a positive electrode active material due to a shuttle phenomenon in which lithium polysulfide formed at the positive electrode is lost out of the positive electrode reaction region and moves between the positive electrode and the negative electrode during the charge / discharge reaction. This results in a decrease in capacity and lifetime. In addition, a side reaction between the lithium polysulfide and the lithium metal eluted from the positive electrode causes a problem that the deterioration of efficiency and lifetime of the lithium metal electrode is accelerated.
이를 위해 종래 기술에서 황을 흡착하는 첨가제나 코팅층을 사용하여 양극 활물질의 유실을 최소화하거나 나노 구조체와의 복합체를 형성함으로써 리튬 폴리설파이드를 구속하는 등의 방법을 사용하였으나 리튬 폴리설파이드의 용출 및 이로 인한 성능 및 수명 저하 문제가 효과적으로 개선되지 못하였다.To this end, in the prior art, a method of restricting lithium polysulfide by minimizing loss of the positive electrode active material by using an additive or a coating layer which adsorbs sulfur or forming a complex with the nanostructure is used. Performance and life degradation issues have not been effectively improved.
이에 본 발명에서는 리튬-황 전지의 성능 및 수명 개선 효과를 확보하고 전지의 반응 안정성을 향상시키기 위해 알칼리 금속 이온을 포함하는 고분자를 첨가제로 포함하는 리튬-황 전지용 전해액을 제공한다.Accordingly, the present invention provides a lithium-sulfur battery electrolyte including an polymer containing an alkali metal ion as an additive in order to secure the performance and lifespan improvement effect of the lithium-sulfur battery and improve the reaction stability of the battery.
구체적으로, 본 발명에 따른 리튬-황 전지용 전해액은 리튬염, 유기용매 및 첨가제를 포함하고, 상기 첨가제는 알칼리 금속염형의 이오노머를 포함한다.Specifically, the lithium-sulfur battery electrolyte according to the present invention includes a lithium salt, an organic solvent and an additive, and the additive includes an alkali metal salt type ionomer.
상기 이오노머(ionomer)는 이온 특성을 갖는 고분자로, 이온성이 없는 공유 결합으로 이루어진 비극성 반복 단위와 이온성 반복 단위로 구성된 공중합체로 이때 이온성 반복 단위는 15 % 이내로 포함되며, 이온성 반복 단위에 포함된 이온성기는 금속 이온으로 중성화(또는 치환)된 것이다. 따라서, 본 발명의 이오노머는 고분자의 주쇄 또는 측쇄에 금속 이온이 도입된 임의의 고분자 재료를 의미한다. 이때 상기 이오노머의 이온성기는 알칼리 금속 이온으로 부분 중화되거나 완전 중화될 수 있다. 일례로, 상기 이오노머 내 포함된 전체 이온성기를 기준으로 50 내지 100 %로 중성화될 수 있다.The ionomer is a polymer having ionic characteristics, a copolymer composed of nonpolar repeating units and ionic repeating units having no ionic covalent bonds, wherein the ionic repeating unit is contained within 15%, and the ionic repeating unit The ionic group contained in is neutralized (or substituted) with metal ions. Accordingly, the ionomer of the present invention means any polymer material in which metal ions are introduced into the main chain or the side chain of the polymer. In this case, the ionic group of the ionomer may be partially neutralized or completely neutralized with alkali metal ions. For example, it may be neutralized by 50 to 100% based on the total ionic groups included in the ionomer.
본 발명에 있어서, 상기 이오노머는 이온성기로 산성기를 포함하는 것으로, 예를 들어 폴리아크릴산(poly(acrylic acid), PAA), 폴리메타크릴산(poly(methacrylic acid), PMA), 폴리스티렌술폰산(Poly(styrenesulfonic acid), PSSA), 폴리아크릴아미도메틸프로판술폰산(poly-2-acrylamido-2-methyl-1-propanesulfonic acid, PAMPSA), 폴리비닐술폰산(poly(vinyl sulfonic acid), PVSA), 나피온(등록 상표)(Nafion) 등을 들 수 있다.In the present invention, the ionomer includes an acidic group as an ionic group, for example, polyacrylic acid (PAA), polymethacrylic acid (PMA), polystyrene sulfonic acid (Poly) (styrenesulfonic acid), PSSA), polyacryllamido-2-methyl-1-propanesulfonic acid (PAMPSA), polyvinyl sulfonic acid (PVSA), Nafion (Nafion) etc. are mentioned.
상기 이온성기는 카르복실레이트기(carboxylate, -C(=O)O-), 설포네이트기(sulfonate, -S(=O)2O-), 설포닐기(sulfonyl, -S(=O)2-), 설페이트기(sulfate, -OS(=O)2O-), 설피네이트기(sulfinate, -S(=O)O-), 포스페이트기(phosphate, -OP(=O)O2-) 및 포스포네이트기(phosphonate, -P(=O)O2-)로 이루어진 군에서 선택되는 1종 이상일 수 있다. 바람직하기로, 상기 이온성기는 카르복실레이트기, 설포네이트기 및 포스포네이트기이며, 보다 바람직하기로는 카르복실레이트기이다.The ionic group is a carboxylate group (carboxylate, -C (= O) O-), a sulfonate group (sulfonate, -S (= O) 2 O-), a sulfonyl group (sulfonyl, -S (= O) 2 ) -, Sulfate group (-OS (= O) 2 O-), sulfinate group (-S (= O) O-), phosphate group (phosphate, -OP (= O) O 2- ) And a phosphonate group (phosphonate, -P (= 0) O 2- ). Preferably, the ionic group is a carboxylate group, a sulfonate group and a phosphonate group, more preferably a carboxylate group.
본 발명에 있어서, 상기 이오노머는 전술한 바의 이온성기를 포함하며, 이 중 일부가 전해액 중에서 전리되어 알칼리 금속으로 치환될 수 있으며, 이와 같이 치환된 형태를 알칼리 금속염형의 이오노머로 지칭한다.In the present invention, the ionomer includes an ionic group as described above, some of which may be ionized in the electrolyte solution and substituted with an alkali metal, and thus the substituted form is referred to as an alkali metal salt ionomer.
본 발명의 알칼리 금속염형의 이오노머는 하기 화학식 1로 표시된다:The alkali metal salt ionomer of the present invention is represented by the following general formula (1):
[화학식 1][Formula 1]
Figure PCTKR2017014351-appb-I000002
Figure PCTKR2017014351-appb-I000002
(상기 화학식 1에서,(In Formula 1,
R1 내지 R3은 서로 같거나 다르며, 각각 독립적으로 수소; 치환 또는 비치환된 탄소수 1 내지 20의 알킬기; 치환 또는 비치환된 탄소수 1 내지 20의 알콕시기; 치환 또는 비치환된 탄소수 2 내지 20의 알케닐기; 치환 또는 비치환된 탄소수 2 내지 20의 알키닐기; 치환 또는 비치환된 탄소수 6 내지 30의 아릴기; 치환 또는 비치환된 탄소수 6 내지 30의 아릴옥시기; 치환 또는 비치환된 탄소수 6 내지 30의 헤테로아릴기; 치환 또는 비치환된 탄소수 6 내지 30의 헤테로아릴옥시기; 치환 또는 비치환된 탄소수 3 내지 20의 사이클로알킬기 또는 치환 또는 비치환된 탄소수 3 내지 20의 헤테로사이클로알킬기이며,R 1 to R 3 are the same as or different from each other, and each independently hydrogen; A substituted or unsubstituted alkyl group having 1 to 20 carbon atoms; A substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms; A substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms; Substituted or unsubstituted C2-C20 alkynyl group; Substituted or unsubstituted aryl group having 6 to 30 carbon atoms; Substituted or unsubstituted aryloxy group having 6 to 30 carbon atoms; A substituted or unsubstituted heteroaryl group having 6 to 30 carbon atoms; A substituted or unsubstituted heteroaryloxy group having 6 to 30 carbon atoms; A substituted or unsubstituted cycloalkyl group having 3 to 20 carbon atoms or a substituted or unsubstituted heterocycloalkyl group having 3 to 20 carbon atoms,
X는 단일 결합; 치환 또는 비치환된 탄소수 1 내지 20의 알칸디일기; 치환 또는 비치환된 탄소수 2 내지 20의 알켄디일기; 비치환된 탄소수 2 내지 20의 알킨디일기; -C(=O)NH-R4; 치환 또는 비치환된 탄소수 6 내지 30의 아릴렌기 또는 치환 또는 비치환된 탄소수 6 내지 30의 헤테로아릴렌기이고, 이때 R4는 탄소수 1 내지 5의 알칸디일기이며,X is a single bond; A substituted or unsubstituted alkanediyl group having 1 to 20 carbon atoms; Substituted or unsubstituted C2-C20 alkenediyl group; Unsubstituted alkynyl group having 2 to 20 carbon atoms; -C (= 0) NH-R 4 ; A substituted or unsubstituted arylene group having 6 to 30 carbon atoms or a substituted or unsubstituted heteroarylene group having 6 to 30 carbon atoms, wherein R 4 is an alkanediyl group having 1 to 5 carbon atoms,
Y는 카르복실레이트기, 설포네이트기, 설포닐기, 설페이트기, 설피네이트기, 포스페이트 및 포스포네이트기로 이루어진 군에서 선택되는 1종 이상이며,Y is at least one selected from the group consisting of carboxylate group, sulfonate group, sulfonyl group, sulfate group, sulfinate group, phosphate and phosphonate group,
M은 알칼리 금속이고,M is an alkali metal,
n은 100 내지 1500의 정수이다.).n is an integer from 100 to 1500).
본 발명에 사용된 용어 “알킬기”는 직쇄 또는 분지쇄일 수 있고, 탄소수는 특별히 한정되지 않으나 1 내지 20, 구체적으로 1 내지 10인 것이 바람직하다. 구체적인 예로는 메틸기, 에틸기, 프로필기, 이소프로필기, 부틸기, t-부틸기, 펜틸기, 헥실기, 헵틸기 등이 있으나, 이들에 한정되지 않는다.The term "alkyl group" used in the present invention may be linear or branched chain, carbon number is not particularly limited but is preferably 1 to 20, specifically 1 to 10. Specific examples include, but are not limited to, methyl, ethyl, propyl, isopropyl, butyl, t-butyl, pentyl, hexyl, heptyl, and the like.
본 발명에 사용된 용어 “알콕시기”는 다른 설명이 없는 한 산소 라디칼을 포함하는 탄소수 1 내지 20의 알킬기를 의미하며 이에 제한되는 것은 아니다.The term "alkoxy group" as used herein refers to an alkyl group having 1 to 20 carbon atoms including an oxygen radical unless otherwise stated, and is not limited thereto.
본 발명에 사용된 용어 “알케닐기”는 다른 설명이 없는 한 적어도 하나의 탄소-탄소 이중 결합을 포함하는 탄소수 1 내지 20의 탄화수소기를 의미하며, 이에 제한되는 것은 아니다.The term "alkenyl group" as used herein refers to a hydrocarbon group having 1 to 20 carbon atoms including at least one carbon-carbon double bond, unless otherwise specified, but is not limited thereto.
본 발명에 사용된 용어 “알키닐기”는 다른 설명이 없는 한 적어도 하나의 탄소-탄소 삼중 결합을 포함하는 탄소수 1 내지 20의 탄화수소기를 의미하며, 이에 제한되는 것은 아니다.The term "alkynyl group" as used herein refers to a hydrocarbon group having 1 to 20 carbon atoms including at least one carbon-carbon triple bond, unless otherwise specified, but is not limited thereto.
본 발명에 사용된 용어 “사이클로알킬기”는 적어도 3개의 탄소 원자로 이루어진 비(non)-방향족 탄소계 고리를 의미한다. 상기 사이클로알킬기는 이에 제한되지는 않지만, 사이클로프로필, 사이클로부틸, 사이클로펜틸, 사이클로헥실 등이 있으나, 이들에 한정되지 않는다.As used herein, the term “cycloalkyl group” means a non-aromatic carbon-based ring of at least three carbon atoms. The cycloalkyl group includes, but is not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and the like, but is not limited thereto.
본 발명에 사용된 용어 “헤테로사이클로알킬기”는 적어도 하나의 탄소가 헤테로 원자로 대체된 사이클로알킬기를 의미한다. 상기 헤테로 원자는 질소(N), 산소(O), 황(S), 인(P) 및 규소(Si)로 이루어진 군에서 선택되는 적어도 하나로 의미한다.As used herein, the term “heterocycloalkyl group” means a cycloalkyl group in which at least one carbon is replaced by a hetero atom. The hetero atom means at least one selected from the group consisting of nitrogen (N), oxygen (O), sulfur (S), phosphorus (P), and silicon (Si).
본 발명에 사용된 용어 “아릴기”는 6 내지 30의 탄소수를 가지며 단일 또는 다중의 방향족 탄소계 고리를 의미한다. 예컨대, 페닐기, 비페닐기, 플루오렌기 등이 있으나, 이에 한정되지 않는다.As used herein, the term “aryl group” refers to a single or multiple aromatic carbon-based ring having 6 to 30 carbon atoms. For example, there may be a phenyl group, a biphenyl group, a fluorene group, and the like, but is not limited thereto.
본 발명에 사용된 용어 “아릴옥시기”는 다른 설명이 없는 한 산소 라디칼을 포함하는 탄소수 6 내지 30의 아릴기를 의미하며 이에 제한되는 것은 아니다.The term "aryloxy group" as used herein refers to an aryl group having 6 to 30 carbon atoms including an oxygen radical, unless otherwise specified, and is not limited thereto.
본 발명에 사용된 용어 “헤테로아릴기”는 적어도 하나의 탄소가 헤테로 원자로 대체된 아릴기를 의미하며, 헤테로 원자는 전술한 바와 같다.As used herein, the term “heteroaryl group” means an aryl group in which at least one carbon is replaced with a hetero atom, wherein the hetero atom is as described above.
본 발명에 사용된 용어 "헤테로아릴옥시기"는 적어도 하나의 탄소가 헤테로 원자로 대체된 아릴옥시기를 의미하며, 헤테로 원자는 전술한 바와 같다.The term "heteroaryloxy group" as used herein refers to an aryloxy group in which at least one carbon is replaced by a hetero atom, wherein the hetero atoms are as described above.
본 발명에 사용된 용어 “알칸디일(alkanediyl)기”는 직쇄 또는 분지쇄의 알칸(alkane)에서 수소 원자 두 개를 뺀 2가의 원자단이며, 일반식 -CnH2n-으로 표시될 수 있다.As used herein, the term “alkanediyl group” refers to a divalent atomic group obtained by subtracting two hydrogen atoms from a straight or branched alkane, and may be represented by the general formula —C n H 2n −. .
본 발명에 사용된 용어 “알켄디일(alkenediyl)기”는 직쇄 또는 분지쇄의 알켄(alkene)에서 수소 원자 두 개를 뺀 2가의 원자단이며, 일반식 -CnHn-으로 표시될 수 있다.As used herein, the term "alkenediyl group" is a divalent atomic group obtained by subtracting two hydrogen atoms from a straight or branched chain alkene, and may be represented by the general formula -C n H n- . .
본 발명에 사용된 용어 “알킨디일(alkynediyl)기”는 직쇄 또는 분지쇄의 알킨(alkyne)에서 수 소 원자 두 개를 뺀 2가의 원자단이다.As used herein, the term "alkynediyl group" is a divalent atomic group minus two hydrogen atoms in a straight or branched alkyne.
본 발명에 사용된 용어 “아릴렌기”는 2가의 방향족 탄소계 고리를 의미하며 탄소수는 6 내지 30, 구체적으로 6 내지 20일 수 있다. 상기 아릴렌기는 2개 이상의 고리가 축합 또는 결합된 구조를 포함할 수 있으며, 다른 환은 방향족, 비방향족 또는 이들의 조합일 수 있다. 예를 들어, 상기 아릴렌기는 페닐렌, 비페닐렌, 나프틸렌, 안트라세닐렌 등이 있으나, 이들에 한정되지 않는다.As used herein, the term “arylene group” refers to a divalent aromatic carbon-based ring and may have 6 to 30 carbon atoms, specifically 6 to 20 carbon atoms. The arylene group may include a structure in which two or more rings are condensed or bonded, and the other ring may be aromatic, non-aromatic, or a combination thereof. For example, the arylene group includes, but is not limited to, phenylene, biphenylene, naphthylene, anthracenylene, and the like.
본 발명에 사용된 용어 “헤테로아릴렌기”는 적어도 하나의 탄소가 헤테로 원자로 대체된 아릴렌기를 의미하며, 헤테로 원자는 전술한 바와 같다.As used herein, the term “heteroarylene group” refers to an arylene group in which at least one carbon is replaced with a hetero atom, wherein the hetero atom is as described above.
본 발명에 사용된 용어 “알칼리 금속”은 리튬(Li), 나트륨(Na) 또는 칼륨(K)이다.The term "alkali metal" as used herein is lithium (Li), sodium (Na) or potassium (K).
본 발명에 사용된 용어 “치환 또는 비치환된”에서 치환은 할로겐, 아미노기, 니트릴기, 니트로기, 하이드록실기. 카르보닐기, 옥시기, 카르보닐옥시기, 이미노카르보닐기, 이미노술포닐기, 술파닐기, 술피닐기, 술포닐기, 술포닐옥시기, 알킬기, 알케닐기, 알키닐기, 아릴기, 헤테로아릴기로 이루어진 군으로부터 선택되는 하나 이상의 치환기로 치환됨을 의미하며, 이들 치환기에 제한되는 것은 아니다.In the term “substituted or unsubstituted” as used herein, substitutions are halogen, amino, nitrile, nitro, hydroxyl groups. Selected from the group consisting of carbonyl group, oxy group, carbonyloxy group, iminocarbonyl group, iminosulfonyl group, sulfanyl group, sulfinyl group, sulfonyl group, sulfonyloxy group, alkyl group, alkenyl group, alkynyl group, aryl group, heteroaryl group It is meant to be substituted with one or more substituents, which are not limited to these substituents.
상기 화학식 1에서 R1 내지 R3은 바람직하기로, 수소; 치환 또는 비치환된 탄소수 1 내지 20의 알킬기; 치환 또는 비치환된 탄소수 1 내지 20의 알콕시기 또는 치환 또는 비치환된 탄소수 6 내지 30의 아릴기이며, 보다 바람직하기로는 수소 또는 치환 또는 비치환된 탄소수 1 내지 20의 알킬기이다.In Formula 1, R 1 to R 3 are preferably hydrogen; A substituted or unsubstituted alkyl group having 1 to 20 carbon atoms; It is a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms or a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, and more preferably hydrogen or a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms.
상기 화학식 1에서 X는 바람직하기로, 단일 결합; 치환 또는 비치환된 탄소수 1 내지 20의 알칸디일기 또는 치환 또는 비치환된 탄소수 6 내지 30의 아릴렌기이다.In Formula 1, X is preferably a single bond; Or a substituted or unsubstituted alkanediyl group having 1 to 20 carbon atoms or a substituted or unsubstituted arylene group having 6 to 30 carbon atoms.
상기 화학식 1에서 Y는 앞서 설명한 바와 같이, 산성기를 포함하는 이온성기이며, 바람직하기로 카르복실레이트기, 설포네이트기 또는 포스포네이트기이며, 보다 바람직하기로는 카르복실레이트기이다.In Formula 1, Y is an ionic group including an acidic group, preferably a carboxylate group, a sulfonate group or a phosphonate group, and more preferably a carboxylate group.
상기 화학식 1에서 M은 알칼리 금속 이온으로, 바람직하기로 리튬 이온일 수 있다.In Formula 1, M is an alkali metal ion, preferably lithium ion.
상기 화학식 1에서 n은 100 내지 1500의 정수이고 바람직하기로 150 내지 500의 정수이다.In Formula 1 n is an integer of 100 to 1500, preferably an integer of 150 to 500.
상기 화학식 1로 표시되는 알칼리 금속염형의 이오노머는 분자 내에 다량의 리튬 이온을 포함함으로써 전해액 내 소량만 첨가하더라도 전해액의 이온 전도도를 크게 증가시킬 수 있다. 종래 리튬 이온 전도도를 높이기 위한 방법으로 리튬 염의 농도를 높일 경우 전해액의 점도가 증가하고 전해염의 열화, 전지 부반응의 발생으로 인해 충분한 효과를 얻지 못하였다. 이와 비교하여 본 발명에서는 고분자 형태의 물질인 알칼리 금속염형의 이오노머를 첨가제로 사용함에 따라 다른 전해염이나 첨가제에는 영향을 미치지 않으면서도 전해액 내 리튬 이온의 농도는 높일 수 있으며, 이는 사이클 진행에 따른 충방전 과정 혹은 전해액 분해에 따른 리튬 이온의 소모를 보완할 수 있다는 이점도 함께 얻을 수 있다.The ionomer of the alkali metal salt type represented by Chemical Formula 1 may significantly increase the ionic conductivity of the electrolyte even if only a small amount of the electrolyte is added in the molecule by including a large amount of lithium ions in the molecule. In the conventional method for increasing the lithium ion conductivity, when the lithium salt concentration is increased, the viscosity of the electrolyte is increased, and the electrolyte salt may not have a sufficient effect due to the deterioration of the electrolyte salt and the occurrence of battery side reactions. In contrast, in the present invention, by using an alkali metal salt type ionomer as an additive, the concentration of lithium ions in the electrolyte can be increased without affecting other electrolytic salts or additives, which is caused by the progress of the cycle. It is also possible to compensate for the consumption of lithium ions due to the discharge process or electrolyte decomposition.
상기 화학식 1의 알칼리 금속염형의 이오노머는 예를 들어, 폴리아크릴산리튬 (PALi), 폴리메타크릴산리튬(PMALi), 폴리스티렌술폰산리튬(PSSLi), 폴리아크릴아미도메틸프로판술폰산리튬(PAMPSLi) 및 폴리비닐술폰산리튬(PVSLi) 으로 이루어진 군에서 선택되는 1종 이상을 포함할 수 있다. 바람직하게는 폴리아크릴산리튬, 폴리스티렌술폰산리튬 및 폴리비닐술폰산리튬으로 이루어진 군에서 선택되는 1종 이상일 수 있으며, 보다 바람직하게는 폴리아크릴산리튬일 수 있다.The alkali metal salt ionomer of the formula (1) is, for example, lithium polyacrylate (PALi), polymethyl methacrylate (PMALi), lithium polystyrene sulfonate (PSSLi), polyacrylamidomethyl propane sulfonate (PAMPSLi) and poly Lithium vinyl sulfonate (PVSLi) may include one or more selected from the group consisting of. Preferably it may be one or more selected from the group consisting of lithium polyacrylate, lithium polystyrene sulfonate and lithium polyvinyl sulfonate, and more preferably lithium polyacrylate.
상기 알칼리 금속염형의 이오노머의 수평균 분자량은 1,000 내지 10,000일 수 있으며, 바람직하기로 1,500 내지 5,000이다. 상기 수평균 분자량이 상기 범위 미만인 경우 목적한 리튬 이온 전도도 개선 효과를 얻을 수 없으며, 상기 범위를 초과하는 경우 이온 교환 과정에서 수용액을 제작하기가 어렵기 때문에 원하는 정도의 치환을 얻기 힘들며, 전해액의 점도가 증가시켜 균일한 분산이 어려울 뿐만 아니라 전해액의 열화 또는 리튬 이온의 이동성 감소와 같은 문제가 발생할 수 있다.The number average molecular weight of the alkali metal salt type ionomer may be 1,000 to 10,000, preferably 1,500 to 5,000. When the number average molecular weight is less than the above range, the desired lithium ion conductivity improvement effect cannot be obtained, and when the number average molecular weight exceeds the above range, it is difficult to obtain a desired degree of substitution because it is difficult to produce an aqueous solution during the ion exchange process, and the viscosity of the electrolyte solution Is not only difficult to uniformly disperse, but may also cause problems such as deterioration of electrolyte solution or reduction of mobility of lithium ions.
본 발명의 알칼리 금속염형의 이오노머는 전술한 이온성기를 갖는 고분자를 알칼리 금속을 포함하는 염기 화합물로 중성화하여 제조할 수 있으며, 이때 중성화 방법으로는 통상의 방법을 사용할 수 있다. 상기 염기 화합물은 수산화나트륨, 탄산나트륨, 수산화리튬 및 수산화칼륨으로 이루어진 군에서 선택되는 1종 이상일 수 있다.The ionomer of the alkali metal salt type of the present invention can be prepared by neutralizing the polymer having the above-mentioned ionic group with a base compound containing an alkali metal, and at this time, a conventional method can be used as the neutralization method. The base compound may be at least one selected from the group consisting of sodium hydroxide, sodium carbonate, lithium hydroxide and potassium hydroxide.
상기 알칼리 금속염형의 이오노머는 리튬-황 전지용 전해액 전체 100 중량%를 기준으로 0.1 내지 5 중량%, 바람직하기로 0.2 내지 2 중량%로 포함될 수 있다. 상기 알칼리 금속염형의 이오노머의 함량이 상기 범위 미만인 경우 리튬 이온 전도도 증가 효과가 미비하며, 이와 반대로 상기 범위를 초과하는 경우 전지 구동시 불필요한 반응을 일으켜 전지의 성능이 저하될 수 있다.The alkali metal salt type ionomer may be included in an amount of 0.1 to 5 wt%, preferably 0.2 to 2 wt%, based on 100 wt% of the total electrolyte for lithium-sulfur batteries. When the content of the alkali metal salt ionomer is less than the above range, the effect of increasing lithium ion conductivity is insignificant. On the contrary, when the alkali ion exceeds the above range, an unnecessary reaction may occur when the battery is driven, thereby degrading the performance of the battery.
본 발명의 리튬-황 전지용 전해액은 이온 전도성을 증가시키기 위해 전해질염으로 리튬염을 포함한다. 상기 리튬염은 본 발명에서 특별히 한정하지 않으며, 해당 기술분야에서 통상적으로 사용 가능한 것이라면 제한없이 사용될 수 있다. 예를 들어, 상기 리튬염은 LiCl, LiBr, LiI, LiClO4, LiBF4, LiB10Cl10, LiPF6, LiCF3SO3, LiCF3CO2, LiC4BO8, LiAsF6, LiSbF6, LiAlCl4, CH3SO3Li, CF3SO3Li, (CF3SO2)2NLi, (C2F5SO2)2NLi, (SO2F)2NLi, (CF3SO2)3CLi, 클로로 보란 리튬, 탄소수 4 이하의 저급지방족 카르본산 리튬, 4-페닐 붕산 리튬 및 리튬 이미드로 이루어진 군에서 선택되는 1종 이상을 포함할 수 있다. 바람직하기로 상기 리튬염은 (SO2F)2NLi(lithium bis(fluorosulfonyl) imide, LiFSI)일 수 있다.The electrolyte solution for lithium-sulfur batteries of the present invention includes lithium salts as electrolyte salts to increase ion conductivity. The lithium salt is not particularly limited in the present invention, and may be used without limitation as long as it is commonly used in the art. For example, the lithium salt is LiCl, LiBr, LiI, LiClO 4 , LiBF 4 , LiB 10 Cl 10 , LiPF 6 , LiCF 3 SO 3 , LiCF 3 CO 2 , LiC 4 BO 8 , LiAsF 6 , LiSbF 6 , LiAlCl 4 , CH 3 SO 3 Li, CF 3 SO 3 Li, (CF 3 SO 2 ) 2 NLi, (C 2 F 5 SO 2 ) 2 NLi, (SO 2 F) 2 NLi, (CF 3 SO 2 ) 3 CLi It may include one or more selected from the group consisting of lithium chloroborane, lower aliphatic carboxylic acid having 4 or less carbon atoms, lithium 4-phenyl borate and lithium imide. Preferably, the lithium salt may be (SO 2 F) 2 NLi (lithium bis (fluorosulfonyl) imide, LiFSI).
상기 리튬염의 농도는 이온 전도도 등을 고려하여 결정될 수 있으며, 예를 들어 0.1 내지 4.0 M, 바람직하게는 0.5 내지 2.0 M 일 수 있다. 상기 리튬염의 농도가 상기 범위 미만인 경우 전지 구동에 적합한 이온 전도도의 확보가 어려우며, 이와 반대로 상기 범위를 초과하는 경우 전해액의 점도가 증가하여 리튬 이온의 이동성을 저하되며 리튬염 자체의 분해 반응이 증가하여 전지의 성능이 저하될 수 있으므로 상기 범위 내에서 적절히 조절한다.The concentration of the lithium salt may be determined in consideration of ionic conductivity and the like, for example, 0.1 to 4.0 M, preferably 0.5 to 2.0 M. When the concentration of the lithium salt is less than the above range, it is difficult to secure ionic conductivity suitable for driving the battery.On the contrary, when the concentration of the lithium salt exceeds the above range, the viscosity of the electrolyte increases to decrease the mobility of the lithium ions and the decomposition reaction of the lithium salt itself increases. Since the performance of the battery may be degraded, it is appropriately adjusted within the above range.
본 발명의 리튬-황 전지용 전해액은 유기 용매를 포함하며, 리튬 이차전지용 전해액에 통상적으로 사용되는 것들을 제한 없이 사용할 수 있으며, 예를 들면 에테르, 에스테르, 아미드, 선형 카보네이트, 환형 카보네이트 등을 각각 단독으로 또는 2종 이상 혼합하여 사용할 수 있다.The electrolyte solution for lithium-sulfur batteries of the present invention includes an organic solvent, and those commonly used in lithium secondary battery electrolytes can be used without limitation, for example, ethers, esters, amides, linear carbonates, cyclic carbonates, and the like, respectively. Or it can mix and use 2 or more types.
상기 에테르계 용매는 비환형 에테르 및 환형 에테르를 포함할 수 있다. The ether solvent may include acyclic ether and cyclic ether.
일례로, 상기 비환형 에테르로는 디메틸 에테르, 디에틸 에테르, 디프로필 에테르, 메틸에틸 에테르, 메틸프로필 에테르, 에틸프로필 에테르, 디메톡시에탄, 디에톡시에탄, 메톡시에톡시에탄, 디에틸렌 글리콜 디메틸 에테르, 디에틸렌 글리콜 디에틸 에테르, 디에틸렌 글리콜 메틸에틸 에테르, 트리에틸렌 글리콜 디메틸 에테르, 트리에틸렌 글리콜 디에틸 에테르, 트리에틸렌 글리콜 메틸에틸 에테르, 테트라에틸렌 글리콜 디메틸 에테르, 테트라에틸렌 글리콜 디에틸 에테르, 테트라에틸렌 글리콜 메틸에틸 에테르, 폴리에틸렌 글리콜 디메틸 에테르, 폴리에틸렌 글리콜 디에틸 에테르, 폴리에틸렌 글리콜 메틸에틸 에테르로 이루어진 군에서 선택되는 1종 이상이 사용될 수 있으나, 이에 한정되는 것은 아니다.In one example, the acyclic ether is dimethyl ether, diethyl ether, dipropyl ether, methylethyl ether, methylpropyl ether, ethylpropyl ether, dimethoxyethane, diethoxyethane, methoxyethoxyethane, diethylene glycol dimethyl Ether, diethylene glycol diethyl ether, diethylene glycol methylethyl ether, triethylene glycol dimethyl ether, triethylene glycol diethyl ether, triethylene glycol methylethyl ether, tetraethylene glycol dimethyl ether, tetraethylene glycol diethyl ether, tetra One or more selected from the group consisting of ethylene glycol methylethyl ether, polyethylene glycol dimethyl ether, polyethylene glycol diethyl ether, polyethylene glycol methylethyl ether may be used, but is not limited thereto.
일례로, 상기 환형 에테르는 1,3-디옥소란, 4,5-디메틸-디옥소란, 4,5-디에틸-디옥소란, 4-메틸-1,3-디옥소란, 4-에틸-1,3-디옥소란, 테트라하이드로퓨란, 2-메틸 테트라하이드로퓨란, 2,5-디메틸 테트라하이드로퓨란, 2,5-디메톡시 테트라하이드로퓨란, 2-에톡시 테트라하이드로퓨란, 2-메틸-1,3-디옥소란, 2-비닐-1,3-디옥소란, 2,2-디메틸-1,3-디옥소란, 2-메톡시-1,3-디옥소란, 2-에틸-2-메틸-1,3-디옥소란, 테트라하이드로파이란, 1,4-디옥산, 1,2-디메톡시 벤젠, 1,3-디메톡시 벤젠, 1,4-디메톡시 벤젠, 아이소소바이드 디메틸 에테르(isosorbide dimethyl ether)로 이루어진 군에서 선택되는 1종 이상이 사용될 수 있으나, 이에 한정되는 것은 아니다.In one example, the cyclic ether is 1,3-dioxolane, 4,5-dimethyl-dioxolane, 4,5-diethyl-dioxolane, 4-methyl-1,3-dioxolane, 4- Ethyl-1,3-dioxolane, tetrahydrofuran, 2-methyl tetrahydrofuran, 2,5-dimethyl tetrahydrofuran, 2,5-dimethoxy tetrahydrofuran, 2-ethoxy tetrahydrofuran, 2- Methyl-1,3-dioxolane, 2-vinyl-1,3-dioxolane, 2,2-dimethyl-1,3-dioxolane, 2-methoxy-1,3-dioxolane, 2 -Ethyl-2-methyl-1,3-dioxolane, tetrahydropyrane, 1,4-dioxane, 1,2-dimethoxy benzene, 1,3-dimethoxy benzene, 1,4-dimethoxy benzene, One or more selected from the group consisting of isosorbide dimethyl ether may be used, but is not limited thereto.
상기 유기 용매 중 에스테르계 용매로는 메틸 아세테이트, 에틸 아세테이트, 프로필 아세테이트, 메틸 프로피오 네이트, 에틸 프로피오네이트, 프로필 프로피오네이트, γ-부티로락톤, γ-발레로락톤, γ-카프로락톤, σ-발레로락톤 및 ε-카프로락톤으로 이루어진 군에서 선택되는 어느 하나 또는 이들 중 2종 이상의 혼합물을 사용할 수 있으나, 이에 한정되는 것은 아니다.Examples of the ester solvent in the organic solvent include methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, γ-butyrolactone, γ-valerolactone, γ-caprolactone, Any one or a mixture of two or more selected from the group consisting of σ-valerolactone and ε-caprolactone may be used, but is not limited thereto.
상기 선형 카보네이트계 용매의 구체적인 예로는 디메틸 카보네이트(dimethyl carbonate, DMC), 디에틸 카보네이트(diethyl carbonate, DEC), 디프로필 카보네이트, 에틸메틸 카보네이트(ethyl methyl carbonate, EMC), 메틸프로필 카보네이트 및 에틸프로필 카보네이트로 이루어진 군에서 선택되는 어느 하나 또는 이들 중 2종 이상의 혼합물 등이 대표적으로 사용될 수 있으나, 이에 한정되는 것은 아니다.Specific examples of the linear carbonate solvent include dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate, ethyl methyl carbonate (EMC), methylpropyl carbonate and ethylpropyl carbonate. Any one selected from the group consisting of, or a mixture of two or more thereof may be representatively used, but is not limited thereto.
또한 상기 환형 카보네이트계 용매의 구체적인 예로는 에틸렌 카보네이트(ethylene carbonate, EC), 프로필렌 카보네이트(propylene carbonate, PC), 1,2-부틸렌 카보네이트, 2,3-부틸렌 카보네이트, 1,2-펜틸렌 카보네이트, 2,3-펜틸렌 카보네이트, 비닐렌 카보네이트, 비닐에틸렌 카보네이트 및 이들의 할로겐화물로 이루어진 군에서 선택되는 어느 하나 또는 이들 중 2종 이상의 혼합물이 있다. 이들의 할로겐화물로는 예를 들면, 플루오로에틸렌 카보네이트(fluoroethylene carbonate, FEC) 등이 있으며, 이에 한정되는 것은 아니다.In addition, specific examples of the cyclic carbonate solvent include ethylene carbonate (EC), propylene carbonate (PC), 1,2-butylene carbonate, 2,3-butylene carbonate, 1,2-pentylene Carbonate, 2,3-pentylene carbonate, vinylene carbonate, vinylethylene carbonate, and any one selected from the group consisting of halides thereof or mixtures of two or more thereof. These halides include, for example, fluoroethylene carbonate (FEC), but are not limited thereto.
본 발명의 리튬 이차전지용 전해액은 전술한 조성 이외에 해당 기술분야에서 통상적으로 사용되는 첨가제를 추가로 포함할 수 있다. 일례로, 질산리튬(LiNO3), 질산칼륨(KNO3), 질산세슘(CsNO3), 질산마그네슘(MgNO3), 질산바륨(BaNO3), 아질산리튬(LiNO2), 아질산칼륨(KNO2), 아질산세슘(CsNO2) 등을 들 수 있다.The lithium secondary battery electrolyte of the present invention may further include an additive commonly used in the art in addition to the above-described composition. For example, lithium nitrate (LiNO 3 ), potassium nitrate (KNO 3 ), cesium nitrate (CsNO 3 ), magnesium nitrate (MgNO 3 ), barium nitrate (BaNO 3 ), lithium nitrite (LiNO 2 ), potassium nitrite (KNO 2) ), Cesium nitrite (CsNO 2 ), and the like.
또한, 본 발명은 상기 리튬-황 전지용 전해액을 포함하는 리튬-황 전지를 제공한다.In addition, the present invention provides a lithium-sulfur battery comprising the electrolyte solution for lithium-sulfur batteries.
상기 리튬-황 전지는 양극, 음극 및 상기 양극과 음극 사이에 개재되는 분리막 및 전해액을 포함하며, 상기 전해액으로서 본 발명에 따른 리튬-황 전지용 전해액을 사용한다.The lithium-sulfur battery includes a positive electrode, a negative electrode, and a separator and an electrolyte interposed between the positive electrode and the negative electrode, and uses the lithium-sulfur battery electrolyte according to the present invention as the electrolyte.
상기 양극은 양극 집전체와 상기 양극 집전체의 일면 또는 양면에 도포된 양극 활물질을 포함할 수 있다.The positive electrode may include a positive electrode current collector and a positive electrode active material coated on one or both surfaces of the positive electrode current collector.
상기 양극 집전체는 양극 활물질을 지지하며, 당해 전지에 화학적 변화를 유발하지 않으면서 높은 도전성을 가지는 것이라면 특별히 제한되는 것은 아니다. 예를 들어, 구리, 스테인리스 스틸, 알루미늄, 니켈, 티타늄, 팔라듐, 소성 탄소, 구리나 스테인리스 스틸 표면에 카본, 니켈, 은 등으로 표면 처리한 것, 알루미늄-카드뮴 합금 등이 사용될 수 있다.The positive electrode current collector supports the positive electrode active material, and is not particularly limited as long as it has high conductivity without causing chemical change in the battery. For example, copper, stainless steel, aluminum, nickel, titanium, palladium, calcined carbon, surface treated with carbon, nickel, silver, etc. on the surface of copper or stainless steel, aluminum-cadmium alloy, and the like can be used.
상기 양극 집전체는 그것의 표면에 미세한 요철을 형성하여 양극 활물질과의 결합력을 강화시킬 수 있으며, 필름, 시트, 호일, 메쉬, 네트, 다공질체, 발포체, 부직포체 등 다양한 형태를 사용할 수 있다.The positive electrode current collector may form fine concavities and convexities on its surface to enhance bonding strength with the positive electrode active material, and may be used in various forms such as a film, a sheet, a foil, a mesh, a net, a porous body, a foam, and a nonwoven fabric.
상기 양극 활물질은 양극 활물질과 선택적으로 도전재 및 바인더를 포함할 수 있다.The cathode active material may include a cathode active material, and optionally a conductive material and a binder.
상기 양극 활물질은 황 원소(Elemental sulfur, S8); Li2Sn(n≥1), 유기황 화합물 또는 탄소-황 폴리머((C2Sx)n: x=2.5 ~ 50, n≥2) 이루어진 군으로부터 선택된 1종 이상일 수 있다. 바람직하게는 무기 황(S8)을 사용할 수 있다.The positive electrode active material is elemental sulfur (S 8 ); Li 2 S n (n ≧ 1), an organic sulfur compound or a carbon-sulfur polymer ((C 2 S x ) n : x = 2.5 ~ 50, n≥2) may be one or more selected from the group consisting of. Preferably inorganic sulfur (S 8 ) can be used.
상기 양극은 상기 양극 활물질 이외에 전이금속 원소, ⅢA족 원소, ⅣA족 원소, 이들 원소들의 황 화합물, 및 이들 원소들과 황의 합금 중에서 선택되는 하나 이상의 첨가제를 더 포함할 수 있다.The positive electrode may further include one or more additives selected from transition metal elements, group IIIA elements, group IVA elements, sulfur compounds of these elements, and alloys of these elements and sulfur, in addition to the positive electrode active material.
상기 전이금속 원소로는 Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Os, Ir, Pt, Au 또는 Hg 등이 포함되고, 상기 ⅢA족 원소로는 Al, Ga, In, Ti 등이 포함되며, 상기 ⅣA족 원소로는 Ge, Sn, Pb 등이 포함될 수 있다.The transition metal element may be Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Os, Ir, Pt, Au or Hg and the like, the Group IIIA element may include Al, Ga, In, Ti, and the like, and the Group IVA element may include Ge, Sn, Pb and the like.
상기 도전재는 전기 전도성을 향상시키기 위한 것으로, 리튬 이차전지에서 화학변화를 일으키지 않는 전자 전도성 물질이면 특별한 제한이 없다.The conductive material is to improve electrical conductivity, and there is no particular limitation as long as it is an electronic conductive material that does not cause chemical change in a lithium secondary battery.
일반적으로 카본블랙(carbon black), 흑연, 탄소섬유, 카본 나노튜브, 금속분말, 도전성 금속산화물, 유기 도전재 등을 사용할 수 있고, 현재 도전재로 시판되고 있는 상품으로는 아세틸렌 블랙계열(쉐브론 케미컬 컴퍼니(Chevron Chemical Company) 또는 걸프 오일 컴퍼니(Gulf Oil Company) 제품 등), 케트젠 블랙(Ketjen Black) EC 계열 (아르막 컴퍼니(Armak Company) 제품), 불칸(Vulcan) XC-72(캐보트 컴퍼니(Cabot Company) 제품) 및 수퍼 P(엠엠엠(MMM)사 제품) 등이 있다. 예를 들면 아세틸렌블랙, 카본블랙, 흑연 등을 들 수 있다.In general, carbon black, graphite, carbon fiber, carbon nanotubes, metal powder, conductive metal oxide, organic conductive materials, and the like can be used, and currently commercially available as a conductive material acetylene black series (Chevron Chemical) Chevron Chemical Company or Gulf Oil Company, etc., Ketjen Black EC series (Armak Company), Vulcan XC-72 (Cabot Company) (Cabot Company) and Super P (MMM). For example, acetylene black, carbon black, graphite, etc. are mentioned.
또한, 상기 양극 활물질은 양극 활물질을 양극 집전체에 유지시키고, 활물질 사이를 이어주는 기능을 갖는 바인더를 추가로 포함할 수 있다. 상기 바인더로서, 예를 들면, 폴리비닐리덴 풀루오라이드-헥사풀루오로프로필렌(PVDF-co-HFP), 폴리비닐리덴 풀루오라이드(polyvinylidene fluoride, PVDF), 폴리아크릴로니트릴(polyacrylonitrile), 폴리메틸 메타크릴레이트(polymethyl methacrylate), 스티렌-부타디엔 고무(styrene butadiene rubber, SBR), 카르복실 메틸 셀룰로오스(carboxyl methyl cellulose, CMC) 등의 다양한 종류의 바인더가 사용될 수 있다.In addition, the cathode active material may further include a binder having a function of maintaining the cathode active material in the cathode current collector and connecting the active material. As the binder, for example, polyvinylidene fluoride-hexafulopropylene (PVDF-co-HFP), polyvinylidene fluoride (PVDF), polyacrylonitrile, poly Various kinds of binders, such as methyl methacrylate, styrene butadiene rubber (SBR), and carboxy methyl cellulose (CMC), may be used.
상기 음극은 음극 집전체 및 상기 음극 집전체 상에 위치하는 음극 활물질을 포함할 수 있다. 또는 상기 음극은 리튬 금속판일 수 있다.The negative electrode may include a negative electrode current collector and a negative electrode active material positioned on the negative electrode current collector. Alternatively, the negative electrode may be a lithium metal plate.
상기 음극 집전체는 음극 활물질의 지지를 위한 것으로, 우수한 도전성을 가지고 리튬 이차전지의 전압영역에서 전기화학적으로 안정한 것이라면 특별히 제한되는 것은 아니며, 예를 들어, 구리, 스테인리스 스틸, 알루미늄, 니켈, 티타늄, 팔라듐, 소성 탄소, 구리나 스테인리스 스틸 표면에 카본, 니켈, 은 등으로 표면 처리한 것, 알루미늄-카드뮴 합금 등이 사용될 수 있다.The negative electrode current collector is for supporting the negative electrode active material, and is not particularly limited as long as it has excellent conductivity and is electrochemically stable in the voltage range of the lithium secondary battery. For example, copper, stainless steel, aluminum, nickel, titanium, Palladium, calcined carbon, surface treated with carbon, nickel, silver or the like on the surface of copper or stainless steel, aluminum-cadmium alloy, or the like may be used.
상기 음극 집전체는 그것의 표면에 미세한 요철을 형성하여 음극 활물질과의 결합력을 강화시킬 수 있으며, 필름, 시트, 호일, 메쉬, 네트, 다공질체, 발포체, 부직포체 등 다양한 형태를 사용할 수 있다.The negative electrode current collector may form fine irregularities on its surface to enhance bonding strength with the negative electrode active material, and may be used in various forms such as film, sheet, foil, mesh, net, porous body, foam, and nonwoven fabric.
상기 음극 활물질은 리튬 (Li+)을 가역적으로 흡장(Intercalation) 또는 방출(Deintercalation)할 수 있는 물질, 리튬 이온과 반응하여 가역적으로 리튬 함유 화합물을 형성할 수 있는 물질, 리튬 금속 또는 리튬 합금을 포함할 수 있다. 상기 리튬 이온(Li+)을 가역적으로 흡장 또는 방출할 수 있는 물질은 예컨대 결정질 탄소, 비정질 탄소 또는 이들의 혼합물일 수 있다. 상기 리튬 이온(Li+)과 반응하여 가역적으로 리튬 함유 화합물을 형성할 수 있는 물질은 예를 들어, 산화주석, 티타늄나이트레이트 또는 실리콘일 수 있다. 상기 리튬 합금은 예를 들어, 리튬(Li)과 나트륨(Na), 칼륨(K), 루비듐(Rb), 세슘(Cs), 프랑슘(Fr), 베릴륨(Be), 마그네슘(Mg), 칼슘(Ca), 스트론튬(Sr), 바륨(Ba), 라듐(Ra), 알루미늄(Al) 및 주석(Sn)으로 이루어지는 군에서 선택되는 금속의 합금일 수 있다. 바람직하게 상기 음극 활물질은 리튬 금속일 수 있으며, 구체적으로, 리튬 금속 박막 또는 리튬 금속 분말의 형태일 수 있다.The negative electrode active material includes a material capable of reversibly intercalating or deintercalating lithium (Li + ), a material capable of reacting with lithium ions to reversibly form a lithium-containing compound, a lithium metal or a lithium alloy can do. The material capable of reversibly occluding or releasing the lithium ions (Li + ) may be, for example, crystalline carbon, amorphous carbon or a mixture thereof. The material capable of reacting with the lithium ions (Li + ) to form a lithium-containing compound reversibly may be, for example, tin oxide, titanium nitrate or silicon. The lithium alloy is, for example, lithium (Li) and sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), francium (Fr), beryllium (Be), magnesium (Mg), calcium ( It may be an alloy of a metal selected from the group consisting of Ca), strontium (Sr), barium (Ba), radium (Ra), aluminum (Al) and tin (Sn). Preferably, the negative electrode active material may be lithium metal, and specifically, may be in the form of a lithium metal thin film or lithium metal powder.
상기 음극 활물질의 형성방법은 특별히 제한되지 않으며, 당업계에서 통상적으로 사용되는 층 또는 막의 형성방법을 이용할 수 있다. 예컨대 압착, 코팅, 증착 등의 방법을 이용할 수 있다. 또한, 집전체에 리튬 박막이 없는 상태로 전지를 조립한 후 초기 충전에 의해 금속판 상에 금속 리튬 박막이 형성되는 경우도 본 발명의 음극에 포함된다.The method of forming the negative electrode active material is not particularly limited, and a method of forming a layer or a film commonly used in the art may be used. For example, a method such as pressing, coating or vapor deposition can be used. The negative electrode of the present invention also includes a case where a metal lithium thin film is formed on a metal plate by initial charging after assembling a battery without a lithium thin film in a current collector.
상기 분리막은 본 발명의 리튬-황 전지에 있어서 양 전극을 물리적으로 분리하기 위한 것으로, 통상 리튬-황 전지에서 분리막으로 사용되는 것이라면 특별한 제한없이 사용가능하며, 특히 전해질의 이온 이동에 대하여 저저항이면서 전해액 함습 능력이 우수한 것이 바람직하다.The separator is used to physically separate both electrodes in the lithium-sulfur battery of the present invention. If the separator is used as a separator in a lithium-sulfur battery, the separator may be used without particular limitation. It is preferable that the electrolyte solution-wetting ability is excellent.
상기 분리막은 다공성 기재로 이루어질 수 있는데 상기 다공성 기재는 통상적으로 전기화학소자에 사용되는 다공성 기재라면 모두 사용이 가능하고, 예를 들면 폴리올레핀계 다공성 막 또는 부직포를 사용할 수 있으나, 이에 특별히 한정되는 것은 아니다.The separator may be made of a porous substrate, and the porous substrate may be used as long as it is a porous substrate commonly used in an electrochemical device. For example, a polyolefin-based porous membrane or a nonwoven fabric may be used, but is not particularly limited thereto. .
상기 폴리올레핀계 다공성 막의 예로는, 고밀도 폴리에틸렌, 선형 저밀도 폴리에틸렌, 저밀도 폴리에틸렌, 초고분자량 폴리에틸렌과 같은 폴리에틸렌, 폴리프로필렌, 폴리부틸렌, 폴리펜텐 등의 폴리올레핀계 고분자를 각각 단독으로 또는 이들을 혼합한 고분자로 형성한 막(membrane)을 들 수 있다.Examples of the polyolefin-based porous membrane, polyolefin-based polymers such as polyethylene, polypropylene, polybutylene, polypentene, such as high density polyethylene, linear low density polyethylene, low density polyethylene, ultra high molecular weight polyethylene, respectively, or a mixture thereof One membrane may be mentioned.
상기 부직포로는 폴리올레핀계 부직포 외에 예를 들어, 폴리에틸렌 테레프탈레이트(polyethyleneterephthalate), 폴리부틸렌 테레프탈레이트(polybutyleneterephthalate), 폴리에스테르(polyester), 폴리아세탈(polyacetal), 폴리아미드(polyamide), 폴리카보네이트 (polycarbonate), 폴리이미드(polyimide), 폴리에테르에테르케톤(polyetheretherketone), 폴리에테르설폰(polyethersulfone), 폴리페닐렌 옥사이드(polyphenyleneoxide), 폴리페닐렌 설파이드(polyphenylenesulfide) 및 폴리에틸렌 나프탈레이트(polyethylenenaphthalate) 등을 각각 단독으로 또는 이들을 혼합한 고분자로 형성한 부직포를 들 수 있다. 상기 부직포의 구조는 장섬유로 구성된 스폰본드 부직포 또는 멜트 블로운 부직포일 수 있다.The nonwoven fabric may be, for example, polyethylene terephthalate, polybutylene terephthalate, polyester, polyacetal, polyamide, polycarbonate, or polycarbonate. ), Polyimide, polyetheretherketone, polyethersulfone, polyphenyleneoxide, polyphenylenesulfide and polyethylenenaphthalate, respectively Or the nonwoven fabric formed from the polymer which mixed these is mentioned. The structure of the nonwoven fabric may be a spunbond nonwoven fabric or a melt blown nonwoven fabric composed of long fibers.
상기 다공성 기재의 두께는 특별히 제한되지 않으나, 1 내지 100 ㎛, 바람직하게는 5 내지 50 ㎛일 수 있다.The thickness of the porous substrate is not particularly limited, but may be 1 to 100 μm, preferably 5 to 50 μm.
상기 다공성 기재에 존재하는 기공의 크기 및 기공도 역시 특별히 제한되지 않으나 각각 0.001 내지 50 ㎛ 및 10 내지 95 %일 수 있다.The pore size and pore present in the porous substrate are also not particularly limited, but may be 0.001 to 50 μm and 10 to 95%, respectively.
상기 전해액은 리튬 이온을 포함하며, 이를 매개로 양극과 음극에서 전기 화학적인 산화 또는 환원 반응을 일으키기 위한 것으로, 전술한 바를 따른다.The electrolyte solution includes lithium ions, and is used for causing an electrochemical oxidation or reduction reaction at the anode and the cathode through the media, as described above.
상기 전해액의 주입은 최종 제품의 제조 공정 및 요구 물성에 따라, 전기화학소자의 제조 공정 중 적절한 단계에서 행해질 수 있다. 즉, 전기화학소자 조립 전 또는 전기화학소자 조립 최종 단계 등에서 적용될 수 있다.The injection of the electrolyte may be performed at an appropriate step in the manufacturing process of the electrochemical device, depending on the manufacturing process and the required physical properties of the final product. That is, it may be applied before the electrochemical device assembly or the final step of the electrochemical device assembly.
본 발명에 따른 리튬-황 전지는 일반적인 공정인 권취(winding) 이외에도 분리막과 전극의 적층(lamination, stack) 및 접음(folding) 공정이 가능하다.Lithium-sulfur battery according to the present invention is capable of lamination (stacking) and folding (folding) of the separator and the electrode, in addition to the general winding (winding).
상기 리튬-황 전지의 형상은 특별히 제한되지 않으며 원통형, 적층형, 코인형 등 다양한 형상으로 할 수 있다.The shape of the lithium-sulfur battery is not particularly limited and may be in various shapes such as cylindrical, stacked, and coin type.
또한, 본 발명은 상기 리튬-황 전지를 단위전지로 포함하는 전지모듈을 제공한다.In addition, the present invention provides a battery module including the lithium-sulfur battery as a unit cell.
상기 전지모듈은 고온 안정성, 긴 사이클 특성 및 높은 용량 특성 등이 요구되는 중대형 디바이스의 전원으로 사용될 수 있다.The battery module may be used as a power source for medium and large devices requiring high temperature stability, long cycle characteristics, and high capacity characteristics.
상기 중대형 디바이스의 예로는 전지적 모터에 의해 동력을 받아 움직이는 파워 툴(power tool); 전기자동차(electric vehicle, EV), 하이브리드 전기자동차(hybrid electric vehicle, HEV), 플러그-인 하이브리드 전기자동차(plug-in hybrid electric vehicle, PHEV) 등을 포함하는 전기차; 전기 자전거(E-bike), 전기 스쿠터(E-scooter)를 포함하는 전기 이륜차; 전기 골프 카트(electric golf cart); 전력저장용 시스템 등을 들 수 있으나, 이에 한정되는 것은 아니다.Examples of the medium-to-large device include a power tool that is driven by an electric motor; Electric vehicles including electric vehicles (EVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and the like; Electric motorcycles including electric bicycles (E-bikes) and electric scooters (E-scooters); Electric golf carts; Power storage systems and the like, but is not limited thereto.
이하, 본 발명의 이해를 돕기 위하여 바람직한 실시예를 제시하나, 하기 실시예는 본 발명을 예시하는 것일 뿐 본 발명의 범주 및 기술사상 범위 내에서 다양한 변경 및 수정이 가능함은 당업자에게 있어서 명백한 것이며, 이러한 변형 및 수정이 첨부된 특허청구범위에 속하는 것도 당연한 것이다.Hereinafter, preferred examples are provided to aid the understanding of the present invention, but the following examples are merely for exemplifying the present invention, and it will be apparent to those skilled in the art that various changes and modifications can be made within the scope and spirit of the present invention. It is natural that such variations and modifications fall within the scope of the appended claims.
실시예Example 및  And 비교예Comparative example : 전해액의 제조: Preparation of Electrolyte
하기 표 1의 조성으로 리튬-황 전지용 전해액을 제조하였다.To prepare a lithium-sulfur battery electrolyte in the composition of Table 1.
리튬염Lithium salt 유기용매(부피비)Organic Solvent (Volume Ratio) 첨가제additive
실시예 1Example 1 1.0 M (SO2F3)2NLi1.0 M (SO 2 F 3 ) 2 NLi DOL1 ):DME2 )(1:1)DOL 1 ) : DME 2 ) (1: 1) 1 중량% LiNO3 0.5 중량% PALi3) 1 wt% LiNO 3 0.5 wt% PALi 3)
실시예 2Example 2 상동Same as above 상동Same as above 1 중량% LiNO3 0.2 중량% PALi1 wt% LiNO 3 0.2 wt% PALi
비교예 1Comparative Example 1 상동Same as above 상동Same as above 1 중량% LiNO3 1 wt% LiNO 3
비교예 2Comparative Example 2 상동Same as above 상동Same as above 1 중량% LiNO3 0.5 중량% 숙신산 리튬1 wt% LiNO 3 0.5 wt% Lithium Succinate
비교예 3Comparative Example 3 상동Same as above 상동Same as above 1 중량% LiNO3 0.5 중량% 옥살산 리튬1 wt% LiNO 3 0.5 wt% Lithium Oxalate
1) 1,3-디옥소란(1,3-dioxolane)2) 디메틸 에테르(dimethyl ether)3) PALi: 폴리아크릴산리튬(Mn= 1800)1) 1,3-dioxolane (1,3-dioxolane) 2) dimethyl ether 3) PALi: lithium polyacrylate (M n = 1800)
실험예Experimental Example 1. 수명 특성 평가 1. Life characteristics evaluation
황을 아세토니트릴 중에서 도전재와 바인더와 볼밀을 사용하여 믹싱하여 양극 활물질 슬러리를 제조하였다. 이때 도전재로는 카본블랙을, 바인더로는 폴리에틸렌옥사이드(분자량 5,000,000g/mol)을 각각 사용하였으며, 혼합 비율은 중량비로 황:도전재:바인더가 90:5:5가 되도록 하였다. 상기 양극 활물질 슬러리를 알루미늄 집전체에 도포한 후 건조하여 양극을 제조하였다.Sulfur was mixed in acetonitrile using a conductive material, a binder, and a ball mill to prepare a positive electrode active material slurry. At this time, carbon black was used as the conductive material and polyethylene oxide (molecular weight 5,000,000 g / mol) was used as the binder, and the mixing ratio was set to be 90: 5: 5 by weight ratio of sulfur: conductive material: binder. The positive electrode active material slurry was applied to an aluminum current collector and then dried to prepare a positive electrode.
두께가 40 ㎛인 리튬 금속 박막을 음극으로 사용하였다.A lithium metal thin film having a thickness of 40 μm was used as the negative electrode.
상기 제조된 양극과 음극을 대면하도록 위치시키고 그 사이에 폴리에틸렌 분리막을 게재한 후, 상기 실시예 및 비교예에서 제조된 전해액을 주입하여 코인형의 전지를 제조하였다.The positive electrode and the negative electrode were placed to face each other, and a polyethylene separator was disposed therebetween, and the electrolyte solution prepared in Examples and Comparative Examples was injected to prepare a coin-type battery.
상기 방법으로 제조된 전지를 0.1 C의 전류밀도로 방전과 충전을 2.5 회 반복한 후 0.2 C의 전류밀도로 방전과 충전을 3회 반복하였으며 이후 0.5 C의 전류밀도로 150 사이클 진행하면서 전지의 수명 특성을 확인하였다. 이때 얻어진 결과를 도 1에 나타내었다.After discharging and recharging the battery prepared by the above method 2.5 times with 0.1 C current density and then repeating the discharging and charging 3 times with 0.2 C current density, the battery life was continued for 150 cycles with current density of 0.5 C. The characteristics were confirmed. The result obtained at this time is shown in FIG.
도 1을 참조하면, 실시예에 따른 전해액을 포함하는 전지의 수명 특성이 비교예에 비해 우수함을 확인할 수 있다.Referring to Figure 1, it can be seen that the life characteristics of the battery including the electrolyte according to the embodiment is superior to the comparative example.
구체적으로, 도 1에 나타낸 바와 같이 첨가제를 포함하지 않는 비교예 1의 경우 60 사이클 이전에 용량이 급격히 떨어지며, 기존 단분자 화합물을 사용한 비교예 2 및 3의 경우 비가역 용량이 80 사이클까지 유지되는 것과 비교하여 본 발명에 따른 실시예 1 및 2의 전해액을 포함하는 경우 비방전 용량의 유지율이 110 사이클까지 안정적으로 유지됨을 확인할 수 있다. 이를 통해 본 발명에 따른 전해액의 경우 리튬 이온 전달을 용이하게 하며 리튬 이온의 고갈이 지연됨을 확인할 수 있다.Specifically, as shown in FIG. 1, in Comparative Example 1, which does not include an additive, the capacity drops sharply before 60 cycles, and in Comparative Examples 2 and 3 using the existing monomolecular compound, the irreversible capacity is maintained up to 80 cycles. In comparison, when the electrolyte solution of Examples 1 and 2 according to the present invention was included, it was confirmed that the retention rate of the specific discharge capacity was stably maintained up to 110 cycles. Through this, in the case of the electrolyte according to the present invention, it is easy to transfer lithium ions and confirm that the depletion of lithium ions is delayed.
본 발명에 따른 리튬-황 전지용 전해액은 알칼리 금속 이온을 포함하는 고분자를 첨가제로 포함함으로써 리튬 이온의 이동 특성이 향상되어 리튬-황 전지의 고용량화, 고안정화 및 장수명화를 가능하게 한다.The electrolyte solution for lithium-sulfur batteries according to the present invention includes a polymer containing alkali metal ions as an additive to improve the mobility of lithium ions, thereby enabling high capacity, high stability, and long life of the lithium-sulfur battery.

Claims (8)

  1. 리튬염, 유기용매 및 첨가제를 포함하고,Including lithium salts, organic solvents and additives,
    상기 첨가제는 알칼리 금속염형의 이오노머를 포함하는, 리튬-황 전지용 전해액.The additive comprises an alkali metal salt type ionomer, electrolyte for a lithium-sulfur battery.
  2. 제1항에 있어서,The method of claim 1,
    상기 알칼리 금속염형의 이오노머는 카르복실레이트기, 설포네이트기, 설포닐기, 설페이트기, 설피네이트기, 포스페이트기 및 포스포네이트기로 이루어진 군에서 선택되는 1종 이상의 이온성기를 포함하는, 리튬-황 전지용 전해액.The ionomer of the alkali metal salt type is lithium-sulfur including at least one ionic group selected from the group consisting of carboxylate group, sulfonate group, sulfonyl group, sulfate group, sulfinate group, phosphate group and phosphonate group Battery electrolyte.
  3. 제1항에 있어서,The method of claim 1,
    상기 알칼리 금속염형의 이오노머는 하기 화학식 1로 표시되는, 리튬-황 전지용 전해액:The alkali metal salt ionomer is represented by the following formula (1), lithium-sulfur battery electrolyte:
    [화학식 1][Formula 1]
    Figure PCTKR2017014351-appb-I000003
    Figure PCTKR2017014351-appb-I000003
    (상기 화학식 1에서,(In Formula 1,
    R1 내지 R3은 서로 같거나 다르며, 각각 독립적으로 수소; 치환 또는 비치환된 탄소수 1 내지 20의 알킬기; 치환 또는 비치환된 탄소수 1 내지 20의 알콕시기; 치환 또는 비치환된 탄소수 2 내지 20의 알케닐기; 치환 또는 비치환된 탄소수 2 내지 20의 알키닐기; 치환 또는 비치환된 탄소수 6 내지 30의 아릴기; 치환 또는 비치환된 탄소수 6 내지 30의 아릴옥시기; 치환 또는 비치환된 탄소수 6 내지 30의 헤테로아릴기; 치환 또는 비치환된 탄소수 6 내지 30의 헤테로아릴옥시기; 치환 또는 비치환된 탄소수 3 내지 20의 사이클로알킬기 또는 치환 또는 비치환된 탄소수 3 내지 20의 헤테로사이클로알킬기이며,R 1 to R 3 are the same as or different from each other, and each independently hydrogen; A substituted or unsubstituted alkyl group having 1 to 20 carbon atoms; A substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms; A substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms; Substituted or unsubstituted C2-C20 alkynyl group; Substituted or unsubstituted aryl group having 6 to 30 carbon atoms; Substituted or unsubstituted aryloxy group having 6 to 30 carbon atoms; A substituted or unsubstituted heteroaryl group having 6 to 30 carbon atoms; A substituted or unsubstituted heteroaryloxy group having 6 to 30 carbon atoms; A substituted or unsubstituted cycloalkyl group having 3 to 20 carbon atoms or a substituted or unsubstituted heterocycloalkyl group having 3 to 20 carbon atoms,
    X는 단일 결합; 치환 또는 비치환된 탄소수 1 내지 20의 알칸디일기; 치환 또는 비치환된 탄소수 2 내지 20의 알켄디일기; 비치환된 탄소수 2 내지 20의 알킨디일기; -C(=O)NH-R4; 치환 또는 비치환된 탄소수 6 내지 30의 아릴렌기 또는 치환 또는 비치환된 탄소수 6 내지 30의 헤테로아릴렌기이고, 이때 R4는 탄소수 1 내지 5의 알칸디일기이며,X is a single bond; A substituted or unsubstituted alkanediyl group having 1 to 20 carbon atoms; Substituted or unsubstituted C2-C20 alkenediyl group; Unsubstituted alkynyl group having 2 to 20 carbon atoms; -C (= 0) NH-R 4 ; A substituted or unsubstituted arylene group having 6 to 30 carbon atoms or a substituted or unsubstituted heteroarylene group having 6 to 30 carbon atoms, wherein R 4 is an alkanediyl group having 1 to 5 carbon atoms,
    Y는 카르복실레이트기, 설포네이트기, 설포닐기, 설페이트기, 설피네이트기, 포스페이트 및 포스포네이트기로 이루어진 군에서 선택되는 1종 이상이며,Y is at least one selected from the group consisting of carboxylate group, sulfonate group, sulfonyl group, sulfate group, sulfinate group, phosphate and phosphonate group,
    M은 알칼리 금속이고,M is an alkali metal,
    n은 100 내지 1500의 정수이다.).n is an integer from 100 to 1500).
  4. 제1항에 있어서,The method of claim 1,
    상기 알칼리 금속염형의 이오노머는 폴리아크릴산리튬, 폴리메타크릴산리튬, 폴리스티렌술폰산리튬, 폴리아크릴아미도메틸프로판술폰산리튬 및 폴리비닐술폰산리튬으로 이루어진 군에서 선택되는 1종 이상을 포함하는, 리튬-황 전지용 전해액.The alkali metal salt type ionomer is lithium-sulfur including one or more selected from the group consisting of lithium polyacrylate, lithium polymethacrylate, lithium polystyrene sulfonate, lithium polyacrylamidomethyl propane sulfonate and lithium polyvinyl sulfonate Battery electrolyte.
  5. 제1항에 있어서,The method of claim 1,
    상기 알칼리 금속염형의 이오노머의 수평균 분자량은 1,000 내지 10,000인, 리튬-황 전지용 전해액.The number average molecular weight of the alkali metal salt type ionomer is 1,000 to 10,000, the lithium-sulfur battery electrolyte.
  6. 제1항에 있어서,The method of claim 1,
    상기 알칼리 금속염형의 이오노머는 리튬-황 전지용 전해액 전체 100 중량%를 기준으로 0.1 내지 5 중량%로 포함되는, 리튬-황 전지용 전해액.The alkali metal salt type ionomer is contained in 0.1 to 5% by weight based on 100% by weight of the total electrolyte solution for lithium-sulfur batteries, electrolyte for lithium-sulfur batteries.
  7. 제1항에 있어서,The method of claim 1,
    상기 리튬염은 LiCl, LiBr, LiI, LiClO4, LiBF4, LiB10Cl10, LiPF6, LiCF3SO3, LiCF3CO2, LiC4BO8, LiAsF6, LiSbF6, LiAlCl4, CH3SO3Li, CF3SO3Li, (CF3SO2)2NLi, (C2F5SO2)2NLi, (SO2F)2NLi, (CF3SO2)3CLi, 클로로 보란 리튬, 탄소수 4 이하의 저급지방족 카르본산 리튬, 4-페닐 붕산 리튬 및 리튬 이미드로 이루어진 군에서 선택되는 1종 이상을 포함하는, 리튬-황 전지용 전해액.The lithium salt is LiCl, LiBr, LiI, LiClO 4 , LiBF 4 , LiB 10 Cl 10 , LiPF 6 , LiCF 3 SO 3 , LiCF 3 CO 2 , LiC 4 BO 8 , LiAsF 6 , LiSbF 6 , LiAlCl 4 , CH 3 SO 3 Li, CF 3 SO 3 Li, (CF 3 SO 2 ) 2 NLi, (C 2 F 5 SO 2 ) 2 NLi, (SO 2 F) 2 NLi, (CF 3 SO 2 ) 3 CLi, chloroborane lithium The electrolyte solution for lithium-sulfur batteries containing 1 or more types chosen from the group which consists of lower aliphatic lithium carboxylates of 4 or less carbon atoms, lithium 4-phenyl borate, and lithium imide.
  8. 제1항 내지 제7항 중 어느 한 항의 전해액을 포함하는, 리튬-황 전지.The lithium-sulfur battery containing the electrolyte solution of any one of Claims 1-7.
PCT/KR2017/014351 2017-05-26 2017-12-08 Electrolyte solution for lithium-sulfur battery and lithium-sulfur battery comprising same WO2018216866A1 (en)

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