WO2020226328A1 - Séparateur fonctionnel, procédé de fabrication associé, et batterie secondaire au lithium le comprenant - Google Patents

Séparateur fonctionnel, procédé de fabrication associé, et batterie secondaire au lithium le comprenant Download PDF

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Publication number
WO2020226328A1
WO2020226328A1 PCT/KR2020/005614 KR2020005614W WO2020226328A1 WO 2020226328 A1 WO2020226328 A1 WO 2020226328A1 KR 2020005614 W KR2020005614 W KR 2020005614W WO 2020226328 A1 WO2020226328 A1 WO 2020226328A1
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conductive carbon
functional
group
polyethylene oxide
separator
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PCT/KR2020/005614
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English (en)
Korean (ko)
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김기현
양승보
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주식회사 엘지화학
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Priority claimed from KR1020200049795A external-priority patent/KR102415168B1/ko
Application filed by 주식회사 엘지화학 filed Critical 주식회사 엘지화학
Priority to JP2020567112A priority Critical patent/JP7100158B2/ja
Priority to US16/972,524 priority patent/US11862811B2/en
Priority to CN202080003211.4A priority patent/CN112243546B/zh
Priority to EP20801821.8A priority patent/EP3790078B1/fr
Publication of WO2020226328A1 publication Critical patent/WO2020226328A1/fr

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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
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/489—Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
    • 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
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • 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 functional separator, a method of manufacturing the same, and a lithium secondary battery including the same, and more particularly, in order to solve the problem caused by the elution of lithium polysulfide, reduction of lithium polysulfide is possible on the surface of the separator. It relates to a functional separator, a method of manufacturing the same, and a lithium secondary battery including the same, which can improve the capacity and life of a battery by coating a material.
  • Electrochemical devices are the field that is receiving the most attention in this respect, and among them, the development of secondary batteries such as lithium-sulfur batteries capable of charging and discharging has become the focus of interest, and in recent years, capacity density and In order to improve the specific energy, research and development on the design of new electrodes and batteries are being conducted.
  • Such an electrochemical device among which a Li-S battery, has a high energy density (theoretical capacity), and is in the spotlight as a next-generation secondary battery that can replace a lithium ion battery.
  • a reduction reaction of sulfur and an oxidation reaction of lithium metal occur during discharge, and at this time, sulfur forms lithium polysulfide (LiPS) of a linear structure from S 8 having a ring structure.
  • the lithium-sulfur battery is characterized by a stepwise discharge voltage until the polysulfide is completely reduced to Li 2 S.
  • an object of the present invention is to form a coating layer in which a conductive carbon capable of reduction of lithium polysulfide and polyethylene oxide for maximizing efficiency is chemically bonded on the surface of a separator in order to solve a problem caused by the elution of lithium polysulfide
  • a functional separator a method of manufacturing the same, and a lithium secondary battery including the same, which can improve the capacity and life of the battery.
  • the base separation membrane In order to achieve the above object, the present invention, the base separation membrane; And a polyethylene oxide (PEO)-conductive carbon composite layer positioned on the surface of the base separation membrane.
  • PEO polyethylene oxide
  • the present invention (a) modifying the end of the polyethylene oxide; (b) preparing a PEO-conductive carbon composite by chemically bonding the terminal functional group of the modified polyethylene oxide and conductive carbon; And (c) coating the prepared PEO-conductive carbon composite on the surface of the base separator; provides a method for producing a functional separator comprising a.
  • the present invention provides a lithium secondary battery comprising; and an electrolyte.
  • the functional separator according to the present invention In order to solve the problem caused by the elution of lithium polysulfide, the functional separator according to the present invention, a method of manufacturing the same, and a lithium secondary battery including the same, have a conductive carbon capable of reducing lithium polysulfide on the surface of the separator, and maximize efficiency.
  • Polyethylene oxide for forming a chemically bonded coating layer has the advantage of improving the capacity and life of the battery.
  • 1 to 3 are graphs comparing and comparing discharge capacity of lithium-sulfur batteries according to an embodiment and a comparative example of the present invention.
  • FIG. 4 is a graph comparing and comparing life characteristics of lithium-sulfur batteries according to an embodiment and a comparative example of the present invention.
  • the functional separator according to the present invention includes a base separator and a polyethylene oxide (PEO)-conductive carbon composite layer positioned on the surface of the base separator.
  • PEO polyethylene oxide
  • the separator is interposed between the positive electrode and the negative electrode (i.e., a physical separator having a function of physically separating the electrode), allowing the transport of lithium ions between the positive electrode and the negative electrode while separating or insulating the positive electrode and the negative electrode from each other. do.
  • a physical separator having a function of physically separating the electrode
  • the resistance to ion migration of the electrolyte is low and the electrolyte-moisture ability is excellent, and may be made of a porous, non-conductive or insulating material.
  • the base separator in a state in which the PEO-conductive carbon composite layer is excluded may be an independent member such as a film, or a coating layer added (adhered or faced) to one or more of the anode and the cathode, and specifically, porous Polymer films, such as ethylene homopolymer, propylene homopolymer, ethylene/butene copolymer, ethylene/hexene copolymer, and a porous polymer film made of polyolefin-based polymer such as ethylene/methacrylate copolymer, etc. alone or laminated thereof Or a conventional porous nonwoven fabric, for example, a nonwoven fabric made of a high melting point glass fiber or polyethylene terephthalate fiber, but is not limited thereto.
  • porous Polymer films such as ethylene homopolymer, propylene homopolymer, ethylene/butene copolymer, ethylene/hexene copolymer, and a porous polymer film made of polyole
  • the conductive carbon constituting the PEO-conductive carbon composite layer is coated with polyethylene oxide (PEO) on the surface of the base separator, and has a pore structure in itself, so that the electrolyte can be freely in and out.
  • the conductive carbon has conductivity as the name suggests, and is a constituent element capable of reducing lithium polysulfide by transferring electrons through such properties.
  • any conductive carbon material capable of exhibiting the above effects may be applied without particular limitation.
  • carbon nanotubes (CNT), graphene, and reduced graphene oxide (rGO) may be exemplified, among which the use of the reduced graphene oxide is preferable, and peeling is advantageous due to thermal expansion. It may be more preferable to use a thermally exfoliated reduced graphene oxide (TErGO) that can exhibit excellent performance by allowing a thin large area coating.
  • TErGO thermally exfoliated reduced graphene oxide
  • the thermally exfoliated reduced graphene oxide may be obtained by heat-treating the graphene oxide to prepare thermally expanded graphene oxide (or thermally exfoliated graphene oxide), followed by reduction treatment.
  • the heat treatment for preparing the thermally expanded graphene oxide may be performed by a known method or various methods of modifying it, and is not particularly limited in the present invention.
  • the heat treatment may be performed for 10 minutes to 3 hours at a temperature range of 300 to 900 °C.
  • the thermal exfoliation-reduced graphene oxide (TErGO) is exfoliated, and may have a thickness of 0.5 to 40 nm, preferably 5 to 30 nm, more preferably 10 to 20 nm, and may have a plate shape or a flake shape.
  • the degree of thermal expansion of the thermally exfoliated reduced graphene oxide (TErGO) may vary from less than 100 m 2 /g to 900 m 2 /g in the range of BET, and the degree of reduction can be measured through XPS or EA. Do.
  • the reduced graphene oxide may be about 9:1.
  • the reduced graphene oxide before peeling has a thickness of about 50 to 500 nm, and because it is easily desorbed when coated in the form of particles, it not only requires the use of a binder (even if it is not a separator), but also has a low coating density to achieve the desired effect. I could't get enough.
  • the present invention can be uniformly and densely coated on a substrate by using a thermally exfoliated reduced graphene oxide in a plate or flake shape having a thickness in a certain range through peeling.
  • a binder may be interposed so that the PEO-conductive carbon composite layer can be more easily coated on the surface of the base separation membrane.
  • TErGO thermally exfoliated reduced graphene oxide
  • rGO reduced graphene oxide
  • polyethylene oxide (PEO) or polyethylene glycol) constituting the PEO-conductive carbon composite layer is used to maximize the reduction efficiency of lithium polysulfide, and is used in a chemical bond with the conductive carbon or Due to its own physical properties, it is possible to improve the bonding strength with the base separation membrane and facilitate the transfer of lithium ions.
  • the polyethylene oxide forms a chemical bond with the conductive carbon, and may be a chain type, a branch type, or a radial type, and may be modified to introduce a specific functional group at the terminal.
  • the functional group may be an amine group (-NH 2 ) and a carboxy group (-COOH).
  • an amide bond can be formed with the carboxy group of the conductive carbon
  • the conductive carbon It may form an ester bond with a hydroxy group (-OH) or a carboxy group of, or form an anhydride by a dehydration condensation reaction.
  • a functional group is not introduced into the polyethylene oxide, the hydroxy group of the polyethylene oxide itself and the carboxy group of the conductive carbon may be bonded to form an ester bond.
  • the polyethylene oxide having a functional group introduced at the terminal may have a structure of a polyethylene oxide-linker-functional group, and examples of the case where the functional group is an amine group include polyethylene oxide-carbonyl-ethylenediamine and ethylenediamine-car Bonyl-polyethylene oxide-carbonyl-ethylenediamine, etc. can be illustrated.
  • the weight ratio of the conductive carbon and polyethylene oxide may be 1: 0.01 to 100, preferably 1: 0.08 to 0.6, more preferably 1: 0.1 to 0.5, and the weight ratio is In the case of deviation, the effects obtained by using polyethylene oxide may be insignificant.
  • the number average molecular weight (Mn) of the polyethylene oxide may be 200 to 10,000,000, preferably 500 to 50,000.
  • the PEO-conductive carbon composite layer may be formed on a part of the surface of the base separation membrane, but in order to maximize the effect of the use of conductive carbon and polyethylene oxide, it is preferably formed on the entire surface of the base separation membrane.
  • the thickness of the PEO-conductive carbon composite layer is 0.1 to 15 ⁇ m, preferably 0.5 to 10 ⁇ m, more preferably 0.5 to 5 ⁇ m, and if the thickness of the PEO-conductive carbon composite layer is less than 0.1 ⁇ m, the conductive network Is not formed sufficiently, so that the electronic conductivity may be lowered, and if it exceeds 15 ⁇ m, the cell resistance increases by obstructing the passage of lithium ions, and there is a fear that a disadvantageous problem may occur in terms of energy density per volume.
  • the coating weight of the PEO-conductive carbon composite layer is 1 to 300 ⁇ g/cm 2 , preferably 3 to 80 ⁇ g/cm 2 , more preferably 5 to 80 ⁇ g/based on the surface area of the base separator to be coated. can be cm 2 . If the coating weight of the PEO-conductive carbon composite layer is less than 1 ⁇ g/cm 2 based on the surface area of the base separator, the effect of the use of conductive carbon and polyethylene oxide may be insignificant, and if it exceeds 300 ⁇ g/cm 2 There may not be any more effects that can be obtained by using conductive carbon and polyethylene oxide.
  • the manufacturing method of the functional separator includes (a) modifying the terminal of polyethylene oxide, (b) chemically bonding the terminal functional group of the modified polyethylene oxide and conductive carbon to prepare a PEO-conductive carbon composite, and ( c) coating the prepared PEO-conductive carbon composite on the surface of the base separator.
  • the method of modifying the terminal of the polyethylene oxide is, for example, an amine compound including two or more amine groups such as ethylenediamine in a solvent with polyethylene oxide. It may be a general modification method of introducing a specific functional group at the end of the compound, such as reacting.
  • the solvent may be water, or organic solvents such as ethanol, acetone, IPA, THF, MC, DMF, DMSO, and DMAc, among which THF or a compound having similar properties is applied as a solvent. It may be desirable.
  • the reaction in step (a) may be carried out for 1 to 24 hours at room temperature to 100°C, preferably 40 to 70°C.
  • the step (b) is a process of preparing a PEO-conductive carbon composite by chemically bonding a hydroxy group or a carboxyl group of a conductive carbon to the terminal functional group of the polyethylene oxide introduced or formed by modification in the step (a).
  • the chemical bonding may be achieved through a reaction under high temperature, and the reaction may be performed at a temperature of, for example, 70 to 150°C, preferably 80 to 120°C, more preferably about 100°C for 8 to 48 hours, preferably Can be carried out for 15 to 30 hours.
  • PEO-conductive carbon composite and base including conductive carbon and polyethylene oxide, as well as bonding strength between the conductive carbon and polyethylene oxide, through chemical bonding between the functional group of polyethylene oxide and the hydroxy group or carboxy group of the conductive carbon formed by the above reaction It is possible to obtain an advantage of smoothing the transfer of lithium ions while improving the bonding strength between the separation membranes.
  • the functional separator according to the present invention is prepared by coating the PEO-conductive carbon composite on the surface of the base separator.
  • the coating is a dropcast, dip-coating method, blade coating method, spray coating method, meyer bar coating method, or vacuum filtration ( vacuum filter).
  • the lithium secondary battery including the functional separator includes a positive electrode, a negative electrode, the functional separator and an electrolyte interposed between the positive electrode and the negative electrode, and includes a lithium-sulfur battery, a lithium air battery, and a lithium metal battery, etc. All known lithium secondary batteries can be exemplified, and among them, lithium-sulfur batteries are preferred.
  • the description of the functional separator included in the lithium secondary battery is instead of the above, and in addition, the remaining positive electrode, negative electrode, and electrolyte applied to the lithium secondary battery may be conventional ones used in the art, and a detailed description thereof is It will be described later.
  • the battery module or battery pack may include a power tool; Electric vehicles including electric vehicles (EVs), hybrid electric vehicles, and plug-in hybrid electric vehicles (PHEVs); Or a system for power storage; It can be used as a power supply for any one or more of medium and large devices.
  • EVs electric vehicles
  • PHEVs plug-in hybrid electric vehicles
  • a system for power storage It can be used as a power supply for any one or more of medium and large devices.
  • a positive electrode composition including a positive electrode active material, a conductive material, and a binder
  • a slurry prepared by diluting it in a predetermined solvent (dispersion medium) is directly coated on the positive electrode current collector, and By drying, an anode layer can be formed.
  • a film obtained by peeling from the support may be laminated on a positive electrode current collector to prepare a positive electrode layer.
  • a positive electrode may be manufactured in various ways using a method widely known to those skilled in the art.
  • the conducting material serves as a path through which electrons move from the positive electrode current collector to the positive electrode active material, thereby imparting electron conductivity, as well as electrically connecting the electrolyte and the positive electrode active material so that lithium ions (Li+) in the electrolyte At the same time, it acts as a pathway to move to and react to sulfur. Therefore, if the amount of the conductive material is insufficient or the role cannot be performed properly, the non-reactive portion of the sulfur in the electrode increases, resulting in a decrease in capacity. In addition, since it adversely affects the high rate discharge characteristics and charge/discharge cycle life, it is necessary to add an appropriate conductive material.
  • the content of the conductive material is preferably added appropriately within the range of 0.01 to 30% by weight based on the total weight of the positive electrode composition.
  • the conductive material is not particularly limited as long as it has conductivity without causing a chemical change in the battery, for example, graphite; Carbon blacks such as denka black, acetylene black, ketjen black, channel black, furnace black, lamp black, and summer black; Conductive fibers such as carbon fibers and metal fibers; Metal powders such as carbon fluoride, aluminum and nickel powder; Conductive whiskers such as zinc oxide and potassium titanate; Conductive metal oxides such as titanium oxide; Conductive materials such as polyphenylene derivatives may be used.
  • Carbon blacks such as denka black, acetylene black, ketjen black, channel black, furnace black, lamp black, and summer black
  • Conductive fibers such as carbon fibers and metal fibers
  • Metal powders such as carbon fluoride, aluminum and nickel powder
  • Conductive whiskers such as zinc oxide and potassium titanate
  • Conductive metal oxides such as titanium oxide
  • Conductive materials such as polyphenylene derivatives may be used.
  • conductive materials include acetylene black-based Chevron Chemical Company, Denka Singapore Private Limited, Gulf Oil Company, Ketjenblack, EC-based Armak Company (Armak Company) product, Vulcan (Vulcan) XC-72 Cabot Company (Cabot Company) product and Super-P (Timcal company product), and the like can be used.
  • the binder is for attaching the positive electrode active material to the current collector well, and must be well soluble in a solvent, and must not only form a conductive network between the positive electrode active material and the conductive material, but also have adequate impregnation of the electrolyte.
  • the binder may be any binder known in the art, and specifically, a fluororesin binder including polyvinylidene fluoride (PVdF) or polytetrafluoroethylene (PTFE); Rubber binders including styrene-butadiene rubber, acrylonitrile-butadiene rubber, and styrene-isoprene rubber; Cellulose-based binders including carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, and regenerated cellulose; Polyalcohol binder; Polyolefin-based binders including polyethylene and polypropylene; Polyimide-based binder, polyester-based binder, silane-based binder; may be a mixture or a copolymer selected from the group consisting of, but is not limited thereto.
  • PVdF polyvinylidene fluoride
  • PTFE polytetrafluoroethylene
  • Rubber binders including styrene-butadiene rubber,
  • the content of the binder may be 0.5 to 30% by weight based on the total weight of the positive electrode composition, but is not limited thereto.
  • the content of the binder resin is less than 0.5% by weight, the physical properties of the positive electrode are deteriorated, so that the positive electrode active material and the conductive material may fall off, and if it exceeds 30% by weight, the ratio of the active material and the conductive material in the positive electrode is relatively reduced. Battery capacity may be reduced, and efficiency may be lowered by acting as a resistance element.
  • the positive electrode composition including the positive electrode active material, the conductive material, and the binder may be diluted in a predetermined solvent and coated on the positive electrode current collector using a conventional method known in the art.
  • a positive electrode current collector is prepared.
  • the positive electrode current collector has a thickness of 3 to 500 ⁇ m.
  • Such a positive electrode current collector is not particularly limited as long as it has high conductivity without causing a chemical change in the battery.
  • stainless steel, aluminum, nickel, titanium, sintered carbon, or aluminum or stainless steel Carbon, nickel, titanium, silver, or the like may be used on the surface of the steel.
  • the current collector may increase the adhesion of the positive electrode active material by forming fine irregularities on its surface, and various forms such as films, sheets, foils, nets, porous bodies, foams, and nonwoven fabrics are possible.
  • a slurry obtained by diluting a positive electrode composition including a positive electrode active material, a conductive material, and a binder in a solvent is applied on the positive electrode current collector.
  • the positive electrode composition including the positive electrode active material, the conductive material, and the binder may be mixed with a predetermined solvent to prepare a slurry.
  • the solvent should be easy to dry and can dissolve the binder well, but it is most preferable that the positive electrode active material and the conductive material can be maintained in a dispersed state without dissolving.
  • the solvent may be water or an organic solvent, and the organic solvent may be at least one selected from the group of dimethylformamide, isopropyl alcohol or acetonitrile, methanol, ethanol, and tetrahydrofuran.
  • the method of applying the slurry-like positive electrode composition for example, Doctor blade coating, Dip coating, Gravure coating, Slit die coating. coating), spin coating, comma coating, bar coating, reverse roll coating, screen coating, cap coating, etc. It can be manufactured.
  • evaporation of the solvent (dispersion medium), the denseness of the coating film, and adhesion between the coating film and the current collector are achieved through a subsequent drying process. At this time, drying is carried out according to a conventional method, and this is not particularly limited.
  • any one capable of occluding and releasing lithium ions can be used, and examples thereof include metal materials such as lithium metal and lithium alloys, and carbon materials such as low crystalline carbon and high crystalline carbon.
  • Soft carbon and hard carbon are typical examples of low-crystalline carbon, and natural graphite, kish graphite, pyrolytic carbon, and liquid crystal pitch-based carbon fiber are high-crystalline carbon.
  • High-temperature calcined carbons such as (Mesophase pitch based carbon fiber), Meso-carbon microbeads, Mesophase pitches, and Petroleum or coal tar pitch derived cokes are typical.
  • alloys containing silicon or oxides such as Li 4 Ti 5 O 12 are also well-known cathodes.
  • the negative electrode may include a binder, and as the binder, polyvinylidenefluoride (PVDF), polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-co-HFP), and polyacrylonitrile (Polyacrylonitrile), polymethylmethacrylate (Polymethylmethacrylate), styrene-butadiene rubber (SBR), and various kinds of binder polymers can be used.
  • PVDF polyvinylidenefluoride
  • PVDF-co-HFP polyvinylidene fluoride-hexafluoropropylene copolymer
  • SBR styrene-butadiene rubber
  • the negative electrode may optionally further include a negative electrode current collector for supporting the negative electrode active layer including the negative electrode active material and the binder.
  • the negative electrode current collector may be specifically selected from the group consisting of copper, stainless steel, titanium, silver, palladium, nickel, alloys thereof, and combinations thereof.
  • the stainless steel may be surface-treated with carbon, nickel, titanium, or silver, and an aluminum-cadmium alloy may be used as the alloy.
  • calcined carbon, a non-conductive polymer surface-treated with a conductive agent, or a conductive polymer may be used.
  • the binder serves as a paste of the negative active material, mutual adhesion between the active materials, adhesion between the active material and the current collector, and a buffering effect on expansion and contraction of the active material.
  • the binder is the same as described above for the binder of the positive electrode.
  • the negative electrode may be a lithium metal or a lithium alloy.
  • the negative electrode may be a thin film of lithium metal, and lithium and one selected from the group consisting of Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Ba, Ra, Al, and Sn It may be an alloy with the above metals.
  • the electrolyte solution includes a solvent and a lithium salt, and may further include additives, if necessary.
  • a solvent a conventional non-aqueous solvent serving as a medium through which ions involved in the electrochemical reaction of a battery can move may be used without particular limitation.
  • the non-aqueous solvent include carbonate-based solvents, ester-based solvents, ether-based solvents, ketone-based solvents, alcohol-based solvents, and aprotic solvents.
  • the carbonate-based solvent dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), methyl ethyl carbonate (MEC) ), ethylene carbonate (EC), propylene carbonate (PC) and butylene carbonate (BC), and the ester solvents include methyl acetate, ethyl acetate, n-propyl acetate, 1,1-dimethylethyl acetate, methyl Propionate, ethyl propionate, ⁇ -butyrolactone, decanolide, valerolactone, mevalonolactone, and caprolactone, and the ether solvents include di Ethyl ether, dipropyl ether, dibutyl ether, dimethoxymethane, trimethoxymethane, dimethoxyethane, die
  • the ketone solvent includes cyclohexanone
  • the alcohol solvent includes ethyl alcohol and isopropyl alcohol
  • the aprotic solvent includes nitriles such as acetonitrile, and amino acids such as dimethylformamide.
  • Dioxolanes such as Drew, 1,3-dioxolane (DOL), and sulfolane.
  • Non-aqueous solvents as described above can be used alone or in combination of two or more, and the mixing ratio in the case of mixing two or more can be appropriately adjusted according to the performance of the intended battery, and 1,3-dioxolane and dimethoxyethane A solvent mixed in a volume ratio of 1: 1 can be illustrated.
  • graphene oxide SE2430, Sixth Element, China
  • thermally exfoliated reduced graphene oxide having a thickness of 15 nm was prepared using a high-speed mixer and an ultrasonic homogenizer.
  • thermally exfoliated reduced graphene oxide and 10 parts by weight of polyethylene oxide were reacted at 100°C for 24 hours with respect to 100 parts by weight of thermally exfoliated reduced graphene oxide.
  • a PEO-conductive carbon composite was prepared in which the amine group and the carboxy group of TErGO were chemically bonded.
  • the prepared PEO-conductive carbon composite was coated on a polyethylene porous base membrane by vacuum filtration and dried, and the weight of the coating layer (PEO-conductive carbon composite layer) was 6 ⁇ g/cm based on the surface area of the base separator. 2 and a thickness of 4 ⁇ m to prepare a functional separator.
  • a functional separator was prepared in the same manner as in Example 1, except that the weight of the coating layer (PEO-conductive carbon composite layer) was changed to 22 ⁇ g/cm 2 based on the surface area of the base separator and the thickness to 6 ⁇ m. .
  • a functional separator was prepared in the same manner as in Example 1, except that the weight of the coating layer (PEO-conductive carbon composite layer) was changed to 74 ⁇ g/cm 2 based on the surface area of the base separator and the thickness was changed to 10 ⁇ m. .
  • the content of polyethylene oxide with amine groups formed at both ends was changed to 50 parts by weight based on 100 parts by weight of TErGO, and the weight of the coating layer (PEO-conductive carbon composite layer) was changed to 16 ⁇ g/cm 2 based on the surface area of the base separator. Except, it was carried out in the same manner as in Example 1 to prepare a functional separator.
  • the content of polyethylene oxide with amine groups formed at both ends was changed to 50 parts by weight based on 100 parts by weight of TErGO, and the weight of the coating layer (PEO-conductive carbon composite layer) was 23 ⁇ g/cm 2 based on the surface area of the base separator, and the thickness was A functional separator was prepared in the same manner as in Example 1, except that it was changed to 6 ⁇ m.
  • the content of polyethylene oxide with amine groups formed at both ends was changed to 50 parts by weight based on 100 parts by weight of TErGO, and the weight of the coating layer (PEO-conductive carbon composite layer) was 64 ⁇ g/cm 2 based on the surface area of the base separator, and the thickness was A functional separator was prepared in the same manner as in Example 1, except that it was changed to 10 ⁇ m.
  • a bare separator made of polyethylene (PE) was prepared.
  • TErGO thermally exfoliated reduced graphene oxide
  • a separator was prepared in the same manner as in Example 1, except that polyethylene imine was used instead of polyethylene oxide having amine groups formed at both ends.
  • the discharge current rate of the prepared lithium-sulfur battery was set at 0.1 C 3 times, 0.2 C 3 times, and then 0.5 C, and then discharge capacity and life characteristics were observed.
  • 1 to 3 are graphs comparing the discharge capacity of a lithium-sulfur battery according to an embodiment and a comparative example of the present invention
  • FIG. 4 is a lifespan of a lithium-sulfur battery according to an embodiment and a comparative example of the present invention. This is a graph comparing and contrasting characteristics.

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Abstract

L'invention concerne: un séparateur fonctionnel ayant un matériau, qui peut réduire le polysulfure de lithium, revêtu sur sa surface de façon à avoir une capacité de batterie et une durée de vie améliorées; un procédé de fabrication de celui-ci; et une batterie secondaire au lithium le comprenant. Le séparateur fonctionnel comprend un séparateur de base et une couche composite au carbone conducteur-oxyde de polyéthylène (PEO) située sur la surface du séparateur de base.
PCT/KR2020/005614 2019-05-03 2020-04-28 Séparateur fonctionnel, procédé de fabrication associé, et batterie secondaire au lithium le comprenant WO2020226328A1 (fr)

Priority Applications (4)

Application Number Priority Date Filing Date Title
JP2020567112A JP7100158B2 (ja) 2019-05-03 2020-04-28 機能性分離膜、その製造方法及びこれを含むリチウム二次電池
US16/972,524 US11862811B2 (en) 2019-05-03 2020-04-28 Separator including polyethylene oxide-conductive carbon composite layer on base separator, method for manufacturing the same, and lithium secondary battery comprising the same
CN202080003211.4A CN112243546B (zh) 2019-05-03 2020-04-28 功能性隔膜、其制造方法和包含所述功能性隔膜的锂二次电池
EP20801821.8A EP3790078B1 (fr) 2019-05-03 2020-04-28 Séparateur fonctionnel, procédé de fabrication associé, et batterie secondaire au lithium le comprenant

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KR10-2020-0049795 2020-04-24

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KR20190052308A (ko) 2017-11-08 2019-05-16 금호타이어 주식회사 그루브의 내구성이 우수한 공기입 타이어
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KR20200049795A (ko) 2017-08-22 2020-05-08 유포리아 리서치 앤 디벨롭먼트 엘티디 강화 알콜성 음료
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