WO2017074116A1 - Polymer electrolyte having multi-layer structure, and all-solid battery comprising same - Google Patents

Polymer electrolyte having multi-layer structure, and all-solid battery comprising same Download PDF

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WO2017074116A1
WO2017074116A1 PCT/KR2016/012283 KR2016012283W WO2017074116A1 WO 2017074116 A1 WO2017074116 A1 WO 2017074116A1 KR 2016012283 W KR2016012283 W KR 2016012283W WO 2017074116 A1 WO2017074116 A1 WO 2017074116A1
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Prior art keywords
polymer electrolyte
solid
lithium
polymer
layer
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PCT/KR2016/012283
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French (fr)
Korean (ko)
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고동욱
양두경
박은경
채종현
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주식회사 엘지화학
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Priority to CN201680033253.6A priority Critical patent/CN107636880B/en
Priority to US15/572,851 priority patent/US10522872B2/en
Priority to JP2017558637A priority patent/JP6450030B2/en
Priority to EP16860299.3A priority patent/EP3285324B1/en
Priority claimed from KR1020160141786A external-priority patent/KR101930477B1/en
Publication of WO2017074116A1 publication Critical patent/WO2017074116A1/en

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    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00Secondary cells; Manufacture thereof
    • H01M10/05Accumulators with non-aqueous electrolyte
    • H01M10/052Li-accumulators
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00Secondary cells; Manufacture thereof
    • H01M10/05Accumulators with non-aqueous electrolyte
    • H01M10/056Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564Accumulators 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
    • H01M10/0565Polymeric materials, e.g. gel-type or solid-type
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00Secondary cells; Manufacture thereof
    • H01M10/05Accumulators with non-aqueous electrolyte
    • H01M10/056Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564Accumulators 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
    • H01M10/0566Liquid materials
    • H01M10/0568Liquid materials characterised by the solutes
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00Secondary cells; Manufacture thereof
    • H01M10/05Accumulators with non-aqueous electrolyte
    • H01M10/058Construction or manufacture
    • H01M10/0585Construction or manufacture of accumulators having only flat construction elements, i.e. flat positive electrodes, flat negative electrodes and flat separators
    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10Energy storage using batteries
    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02PCLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50Manufacturing or production processes characterised by the final manufactured product

Definitions

  • the present invention relates to a polymer electrolyte for an all-solid-state battery having a multi-layer structure, and more specifically, the EO: Li molar ratio of a polyethylene oxide (PEO) -based polymer and a lithium salt is A multi-layered polymer electrolyte comprising different first polymer electrolyte layers and second polymer electrolyte layers.
  • PEO polyethylene oxide
  • secondary batteries have been increasing in demand for various applications as power sources for PCs, video cameras, mobile phones, and the like, or as power sources for electric vehicles and power storage media.
  • the secondary batteries especially lithium-based secondary batteries have higher capacity density than other secondary batteries and can operate at high voltage, and thus are used in information-related devices and communication devices as secondary batteries for compact and lightweight, and have recently been used for electric vehicles and hybrid vehicles.
  • the development of high power and high capacity lithium-based secondary batteries is in progress.
  • a typical lithium-based secondary battery is composed of an electrolyte containing a positive electrode (positive electrode, cathode), a negative electrode (negative electrode, anode) and a lithium salt interposed therebetween, and such an electrolyte is a non-aqueous liquid electrolyte or a solid electrolyte.
  • a non-aqueous liquid electrolyte is used for the electrolyte, since the electrolyte penetrates into the positive electrode, an interface between the positive electrode active material constituting the positive electrode and the electrolyte tends to be formed, and thus has high electrical performance.
  • a lithium secondary battery uses a flammable organic solvent in the liquid electrolyte, it is necessary to install a safety device in order to prevent ignition and rupture that may occur due to overcurrent due to a short circuit. It is also built. In addition, in order to prevent such a phenomenon, there may be a restriction in selecting a battery material or designing a battery structure.
  • an all-solid-state battery which uses a solid electrolyte instead of a liquid electrolyte is advanced. Since an all-solid-state battery does not contain a flammable organic solvent, it has the advantage of simplifying a safety device, and is recognized as a battery excellent in manufacturing cost and productivity. Moreover, since it is easy to stack a junction structure including a pair of electrode layers including an anode (positive electrode) layer and a cathode (negative electrode) layer and a solid electrolyte layer sandwiched between these electrode layers, it is stable and has a high capacity, In addition, it is expected as a technology that can produce a battery of high power.
  • LiNbO 3 LiNbO 3 -coated LiCoO 2 as cathode material for all solid-state lithium secondary batteries
  • Electrochemistry Communications 9 (2007), 1486 ⁇ 1490 is applied to the surface of LiCoO 2 (anode active material).
  • LiNbO 3 Lithium niobate
  • This technique is to obtain a high power battery in such a manner as to reduce the interface resistance between the surface of LiCoO 2 is coated with LiNbO 3, LiCoO 2 as solid by suppressing the reaction between the electrolyte material, the solid electrolyte material and LiCoO 2.
  • Japanese Laid-Open Patent Publication No. 2004-206942 discloses a second solid electrolyte layer which does not chemically react with the first solid electrolyte and has lower ion conductivity than the first solid electrolyte layer (sulfide-based solid electrolyte material).
  • an all-solid-state battery formed between the first solid electrolyte layer and a cathode made of metallic lithium. This is to suppress the reaction between the first solid electrolyte layer and the metal lithium through the formation of a second solid electrolyte layer having low ion conductivity.
  • Patent Document 1 Korean Unexamined Patent Publication No. 2012-0092918 "Polymer composite electrolyte for lithium secondary battery and lithium secondary battery comprising same"
  • Patent Document 2 Japanese Unexamined Patent Publication No. 2004-206942 "All-solid-state lithium battery”
  • Non-Patent Document 1 Qian, Jiangfeng, et al. "High rate and stable cycling of lithium metal anode.” Nature communications 6 (2015)
  • Non-Patent Document 2 LiNbO3-coated LiCoO2 as cathode material for all solid-state lithium secondary batteries
  • Electrochemistry Communications 9 (2007), 1486-1490 Electrochemistry Communications 9 (2007), 1486-1490.
  • An all-solid-state battery to which a solid polymer electrolyte is applied is hard to express sufficient output or capacity at room temperature but also at 60 ° C or 80 ° C.
  • the reasons for this are firstly low ionic conductivity of the polymer electrolyte and secondly, interfacial resistance between lithium and the polymer electrolyte.
  • an object of the present invention is to provide a polymer electrolyte for an all-solid-state battery which significantly lowers the interface resistance between lithium and a polymer electrolyte.
  • the present invention provides a polymer electrolyte layer having a molar ratio of EO: Li of a polyethylene oxide (PEO) -based polymer and a lithium salt of 1: 1 to 7: 1; And
  • It provides a polymer electrolyte for an all-solid-state battery comprising a multi-layer structure.
  • the thickness of the first polymer electrolyte layer may be 1 to 5 ⁇ m.
  • the thickness of the second polymer electrolyte layer may be 5 ⁇ 50 ⁇ m.
  • the weight average molecular weight (Mw) of the polyethylene oxide polymer may be 1,000,000 to 8,000,000.
  • 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 , LiAsF 6 , LiSbF 6 , LiAlCl 4 , CH 3 SO 3 Li , CF 3 SO 3 Li, LiSCN, LiC (CF 3 SO 2 ) 3 , (CF 3 SO 2 ) 2 NLi, (FSO 2 ) 2 NLi, chloroborane lithium, lower aliphatic carbonate, lithium 4-phenyl borate, It may include one selected from imides and combinations thereof.
  • the second polymer electrolyte layer may be cross-linked by a crosslinkable monomer to form a semi-interpenetrating polymer network (semi-IPN).
  • a crosslinkable monomer to form a semi-interpenetrating polymer network (semi-IPN).
  • the crosslinkable monomer may include a — (CH 2 —CH 2 —O) —repeating unit.
  • the crosslinkable monomer may include 2 to 8 alkylenically unsaturated bonds at the terminals.
  • the crosslinkable monomer may be included in an amount of 5 to 50 wt% based on the polyethylene oxide polymer and the lithium salt.
  • the present invention is an all-solid-state battery comprising a positive electrode, a negative electrode and a solid polymer electrolyte interposed therebetween,
  • the solid polymer electrolyte provides an all-solid-state battery, which is a polymer electrolyte for an all-solid-state battery having the multilayer structure.
  • the first polymer electrolyte layer may be disposed to face the cathode.
  • the solid polymer electrolyte of the present invention When the solid polymer electrolyte of the present invention is applied to an all-solid-state battery, the interfacial resistance with lithium and the discharge overvoltage are significantly reduced, resulting in sufficient discharge capacity and improved output characteristics and energy density.
  • FIG. 1 is a graph showing the interfacial resistance of a lithium metric battery according to Comparative Example 1.
  • FIG. 2 is a graph showing the interfacial resistance of the lithium symmetric battery according to Example 1.
  • Example 3 is a cross-sectional comparison diagram of the all-solid-state battery according to Comparative Example 2 (a) and Example 2 (b).
  • Example 4 is a graph comparing discharge capacities of all-solid-state batteries according to Comparative Example 2 (a) and Example 2 (b).
  • the solid polymer electrolyte applied to an all-solid-state battery includes a polyethylene oxide (PEO) -based polymer and a lithium salt
  • the EO: Li molar ratio of the polyethylene oxide-based polymer and the lithium salt is A multi-layered polymer electrolyte comprising a different first polymer electrolyte layer and a second polymer electrolyte layer is disclosed.
  • the first polymer electrolyte layer is applied to lower the interfacial resistance
  • the EO: Li molar ratio of the polyethylene oxide polymer and the lithium salt is selected and prepared within the range of 1: 1 to 7: 1.
  • the lithium salt is doped at a high rate and thinned to a thickness of 1 to 5 ⁇ m, the ion conductivity is slightly lowered, but the interface resistance can be significantly lowered.
  • the second polymer electrolyte layer is applied to prevent the phenomenon caused by the generation of dendrite by increasing the mechanical strength, and the molar ratio of EO: Li of the polyethylene oxide polymer and the lithium salt is 30: 1 to 8: 1 It selects and manufactures in the range.
  • the thickness of the second polymer electrolyte layer may be 5 to 50 ⁇ m.
  • the second polymer electrolyte layer may be crosslinked by a crosslinkable monomer to form a semi-interpenetrating polymer network (semi-IPN) structure.
  • the semi-IPN structure can increase the strength of the solid polymer electrolyte, and the higher the strength, the more physically it can suppress the generation of lithium dendrites on the electrode surface.
  • the weight average molecular weight (Mw) of the polyethylene oxide-based polymer may form a more dense semi-IPN structure when a relatively high molecular weight is applied within the range of 1,000,000 to 8,000,000.
  • the crosslinkable monomer may be a bifunctional or more than one polyfunctional monomer, and may include a-(CH 2 -CH 2 -O) -repeat unit, and may form an alkylenically unsaturated bond within the range of 2 to 8 polymerizable at both ends. It is preferable to include.
  • the alkylenically unsaturated bond is a hydrocarbon group including at least one carbon-carbon double bond or triple bond, an ethenyl group, 1-propenyl group, 2-propenyl group, 2-methyl-1-propenyl group, 1-butenyl group, 2-butenyl group, ethynyl group, 1-propynyl group, 1-butynyl group, 2-butynyl group, and the like, but are not limited thereto.
  • Such alkylenically unsaturated bonds act as a crosslinking point to form a semi-IPN structure by crosslinking the polyethylene oxide polymer through a polymerization process.
  • the crosslinkable monomer may include polyethylene glycol diacrylate (PEGDA), polyethylene glycol dimethacrylate (PEGDMA), polypropylene glycol diacrylate (Poly ( propylene glycol diacrylate: PPGDA), poly (propylene glycol) dimethacrylate (PPGDMA) and combinations thereof, and preferably polyethylene glycol diacrylate (PEGDA).
  • PEGDA polyethylene glycol diacrylate
  • PEGDMA polyethylene glycol dimethacrylate
  • PPGDA polypropylene glycol diacrylate
  • PPGDMA poly (propylene glycol) dimethacrylate
  • PEGDA polyethylene glycol diacrylate
  • crosslinkable monomer is preferably included in the range of 5 to 50 wt% based on the weight of the polyethylene oxide-based polymer to form a semi-IPN structure suitable for the purpose of the present invention.
  • Lithium salts commonly applied to the first polymer electrolyte layer and the second polymer electrolyte layer according to the present invention may be dissociated into lithium ions to penetrate into the first polymer electrolyte layer and the second polymer electrolyte layer and move freely.
  • any lithium salt can be used as long as it is commonly used in lithium batteries, but preferably LiCl, LiBr, LiI, LiClO 4 , LiBF 4 , LiB 10 Cl 10 , LiPF 6 , LiCF 3 SO 3 , LiCF 3 CO 2 , LiAsF 6 , LiSbF 6 , LiAlCl 4 , CH 3 SO 3 Li, CF 3 SO 3 Li, LiSCN, LiC (CF 3 SO 2 ) 3 , (CF 3 SO 2 ) 2 NLi, (FSO 2 ) 2 NLi, chloroborane lithium, lower aliphatic lithium carbonate, lithium 4-phenyl borate, imide and combinations thereof, but more preferably Lithium bis (fluorosulfonyl) imide (LiFSI), preferably represented by (FSO 2 ) 2 NLi, is possible.
  • LiFSI Lithium bis (fluorosulfonyl) imide
  • the manufacturing method of the first polymer electrolyte layer or the second polymer electrolyte layer of the present invention is not limited in the present invention, and a mixing and molding process may be used by a wet or dry method as is known.
  • the thickness of the solid polymer electrolyte of the present invention may be selectively prepared within the range of 1 to 50 ⁇ m.
  • an all-solid-state battery including the solid polymer electrolyte of the present invention interposed between a positive electrode and a negative electrode will be described an all-solid-state battery in which the first polymer electrolyte layer faces the negative electrode and the interface resistance is significantly reduced.
  • the electrode active material may be a positive electrode active material when the electrode proposed in the present invention is a positive electrode, a negative electrode active material when the negative electrode.
  • each electrode active material can be any active material applied to a conventional electrode, and is not particularly limited in the present invention.
  • the positive electrode or negative electrode active material used in the present invention varies depending on the type of conductive ions of the intended all-solid-state battery.
  • the all-solid-state battery according to the present invention is an all-solid lithium secondary battery
  • the positive or negative electrode active material occludes or releases lithium ions.
  • the positive electrode or negative electrode active material used in the present invention can generally react with the solid electrolyte material described above to form a high resistance portion.
  • the positive electrode active material may vary depending on the use of the lithium secondary battery, and the specific composition uses a known material. For example, any one selected from the group consisting of lithium-phosphate-iron compound, lithium cobalt-based oxide, lithium manganese-based oxide, lithium copper oxide, lithium nickel-based oxide and lithium manganese composite oxide, lithium-nickel-manganese-cobalt-based oxide And lithium transition metal oxides.
  • M is at least one selected from metals of Groups 2 to 12
  • X is F
  • the negative electrode active material may be one selected from the group consisting of lithium metal, lithium alloy, lithium metal composite oxide, lithium-containing titanium composite oxide (LTO), and combinations thereof.
  • the lithium alloy may be an alloy consisting of lithium and at least one metal selected from Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Ba, Ra, Al and Sn.
  • the lithium metal composite oxide is any one metal (Me) oxide (MeO x ) selected from the group consisting of lithium and Si, Sn, Zn, Mg, Cd, Ce, Ni, and Fe, for example, Li x Fe 2 O 3 (0 ⁇ x ⁇ 1) or Li x WO 2 (0 ⁇ x ⁇ 1).
  • a conductive material, a polymer electrolyte, a binder, a filler, and the like may be further added to the active material, and the conductive material is not particularly limited as long as it has conductivity without causing chemical changes to the battery.
  • the conductive material is not particularly limited as long as it has conductivity without causing chemical changes to the battery.
  • graphite Carbon blacks such as carbon 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 powder, aluminum powder and nickel powder
  • Conductive whiskeys such as zinc oxide and potassium titanate
  • Conductive metal oxides such as titanium oxide
  • Conductive materials such as polyphenylene derivatives and the like can be used.
  • conductive materials include Chevron Chemical Company, Denka Singapore Private Limited, Gulf Oil Company, Ketjenblack and EC Armak, which are acetylene black series. Company (Armak Company), Vulcan XC-72 Cabot Company, Super P (manufactured by Timcal), and the like can be used.
  • the binder is a component that assists in bonding the active material and the conductive material to the current collector, and is generally added in an amount of 1 to 50 wt% based on the total weight of the mixture including the electrode active material.
  • binders include polyvinylidene fluoride, polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene, poly Propylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene butylene rubber, fluorine rubber, various copolymers, and the like.
  • the filler is not particularly limited as long as it is a fibrous material without causing chemical change in the battery.
  • the filler include olefinic polymers such as polyethylene and polypropylene; Fibrous materials, such as glass fiber and carbon fiber, are used.
  • the first polymer electrolyte layer is disposed to face the negative electrode, and a second polymer electrolyte layer is formed thereon, and an anode is formed thereon. If the stacking order of the first and second polymer electrolyte layers is reversed, the resistance of the battery may increase and the discharge capacity may decrease, which is not preferable.
  • the interfacial resistance may increase and the discharge capacity may be lowered, and if the second polymer electrolyte layer is out of the above range, the resistance of the electrolyte-separation membrane layer may increase. Discharge capacity may be lowered, which is undesirable.
  • the manufacture of an all-solid-state battery is a dry compression process in which an electrode and a solid electrolyte are prepared in powder form, and then put into a predetermined mold and pressed, or a slurry coating is prepared after coating and drying in the form of a slurry composition containing an active material, a solvent, and a binder. It is manufactured through the process.
  • the production of the all-solid-state battery having the above configuration is not particularly limited in the present invention, and a known method can be used.
  • a solid electrolyte is disposed between the positive electrode and the negative electrode and then compression molded to assemble the cell.
  • the assembled cell is installed in an outer packaging material and sealed by heat compression.
  • laminate packs such as aluminum and stainless steel and cylindrical or rectangular metal containers are very suitable.
  • the method of coating the electrode slurry on the current collector is a method of distributing the electrode slurry on the current collector and then uniformly dispersing it using a doctor blade or the like, die casting, comma coating. , Screen printing, and the like.
  • the electrode slurry may be bonded to the current collector by pressing or lamination after molding on a separate substrate. At this time, by adjusting the concentration of the slurry solution, or the number of coating, it is possible to control the coating thickness to be finally coated.
  • the drying process is a process of removing the solvent and water in the slurry to dry the slurry coated on the metal current collector, and may vary depending on the solvent used. In one example, it is carried out in a vacuum oven at 50 ⁇ 200 °C.
  • a drying method the drying method by irradiation with warm air, hot air, low humidity wind, vacuum drying, (far) infrared rays, an electron beam, etc. are mentioned, for example. Although it does not specifically limit about drying time, Usually, it carries out in 30 second-24 hours.
  • a cooling process may be further included, and the cooling process may be slow cooling to room temperature so that the recrystallized structure of the binder is well formed.
  • a pressing process may be performed in which the electrode is passed between two hot-heated rolls and compressed to a desired thickness.
  • the said rolling process is not specifically limited in this invention, A well-known rolling process is possible. In one example, it is passed between the rotating rolls or performed using a flat plate press.
  • n represents the number of moles of PEO corresponding to 1 mol of Li of the lithium salt
  • X is a semi-IPN structure in what is referred to as 'PEO n -lithium salt-X' It means crosslinked with.
  • a 3 ⁇ m polymer electrolyte membrane and a PEO 5 -LiFSI membrane were prepared by a solution casting method.
  • a 20 ⁇ m polymer electrolyte membrane and a PEO 20 -LiFSI membrane were prepared by a solution casting method.
  • initiator BPO Benzoyl peroxide
  • a 20 ⁇ m polymer electrolyte membrane and a PEO 20 -LiFSI-X membrane were prepared by a solution casting method using the mixed solution.
  • a 3 ⁇ m polymer electrolyte membrane and a PEO 2 -LiFSI membrane were prepared by a solution casting method.
  • a 10 ⁇ m polymer electrolyte membrane and a PEO 12 -LiFSI membrane were prepared by a solution casting method.
  • a lithium symmetric cell is applied by applying the PEO 5 -LiFSI film of Preparation Example 1 to the surface of a lithium metal and applying the PEO 20 -LiFSI-X film of Preparation Example 3 therebetween.
  • a lithium symmetric cell is applied by applying the PEO 5 -LiFSI film of Preparation Example 1 to the surface of a lithium metal and applying the PEO 20 -LiFSI-X film of Preparation Example 3 therebetween.
  • a lithium symmetric cell was fabricated by applying the PEO 20 —LiFSI-X film of Preparation Example 3 between lithium.
  • a positive electrode having a porosity of 10% or less and a loading of 2 mAh / cm 2 was prepared by mixing LFP (LiFePO 4 ) active material, a conductive material, and a polymer electrolyte to a size of 10.6 cm 2 .
  • the positive electrode prepared in step 1 was stacked on the second polymer electrolyte to prepare an all-solid-state battery as shown in FIG. 3 (b).
  • a positive electrode having a porosity of 10% or less and a loading of 2 mAh / cm 2 was prepared by mixing LFP (LiFePO 4 ) active material, a conductive material, and a polymer electrolyte to a size of 10.6 cm 2 .
  • An all-solid-state battery was manufactured by stacking the positive electrode prepared in step 1 on the second polymer electrolyte.
  • a positive electrode having a porosity of 10% or less and a loading of 2 mAh / cm 2 was prepared by mixing LFP (LiFePO 4 ) active material, a conductive material, and a polymer electrolyte to a size of 10.6 cm 2 .
  • step 3 The positive electrode prepared in step 1 was stacked to produce an all-solid-state battery as shown in FIG.
  • a positive electrode having a porosity of 10% or less and a loading of 2 mAh / cm 2 was prepared by mixing LFP (LiFePO 4 ) active material, a conductive material, and a polymer electrolyte to a size of 10.6 cm 2 .
  • the first polymer electrolyte of PEO 5 -LiFSI of Preparation Example 1 was mounted on the second polymer electrolyte.
  • An all-solid-state battery was manufactured by stacking the positive electrode prepared in step 1 on the first polymer electrolyte.
  • a positive electrode having a porosity of 10% or less and a loading of 2 mAh / cm 2 was prepared by mixing LFP (LiFePO 4 ) active material, a conductive material, and a polymer electrolyte to a size of 10.6 cm 2 .
  • a second polymer electrolyte of PEO 20 -LiFSI of Preparation Example 2 was mounted on the second polymer electrolyte.
  • An all-solid-state battery was manufactured by stacking the positive electrode prepared in step 1 on the second polymer electrolyte.
  • Example 1 and Comparative Example 1 and the all-solid-state cells of Example 3 and Comparative Examples 3 and 4 were measured by electrochemical impedance spectroscopy (EIS) measurement.
  • EIS electrochemical impedance spectroscopy
  • the resistance of the cell to which only PEO 20 -LiFSI-X, which is Comparative Example 1 shown in FIG. 1, is 350 ⁇
  • the battery applied as an interlayer was found to have a very low resistance of about 130 ⁇ despite the increase in thickness of 6 ⁇ m. Therefore, it can be seen that the PEO 5 -LiFSI film has a very low interfacial resistance with lithium.
  • the resistance of the all-solid-state battery in which PEO 2 -LiFSI and PEO 20 -LiFSI based on the lithium negative electrode of Example 3 were sequentially applied was 200 ⁇
  • Comparative Example 3 which changed the positions of the first polymer and the second polymer, was used.
  • a negative electrode based on PEO and PEO 5 20 -LiFSI -LiFSI was the resistance of the all-solid battery are applied sequentially appeared as 350 ⁇
  • the resistance of the all-solid-state battery sequentially applied was 2200 ⁇ .
  • the interfacial resistance of the battery in which the lithium negative electrode reference first polymer electrolyte layer is disposed facing lithium and the second polymer electrolyte layer is disposed thereon is lower, and that the first polymer electrolyte layer is the first polymer electrolyte layer than the battery using only the second polymer electrolyte layer. It can be seen that the interface resistance of the battery using the polymer electrolyte layer and the second polymer electrolyte layer at the same time is lower.
  • an all-solid-state battery (Comparative Example 2, (a)) using only PEO 20 -LiFSI-X has a high positive electrode loading and a high interfacial resistance with lithium, so that the discharge capacity is 130 mAh / g. It was not expressed.
  • an all-solid-state battery (Examples 2 and (b)) in which the PEO 5 -LiFSI polymer electrolyte membrane of the present invention is applied between the lithium anode and the second polymer electrolyte PEO 20 -LiFSI-X (Interlayer) is lithium. It was confirmed that the interfacial resistance with and the discharge overvoltage is reduced significantly, and sufficient discharge capacity of 155 mAh / g is implemented. Therefore, when the PEO 5 -LiFSI polymer electrolyte membrane, which is the first polymer electrolyte, is applied to a battery, output characteristics and energy density can be improved.

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Abstract

The present invention relates to a polymer electrolyte for an all-solid battery, having a multi-layer structure and, more particularly, to a polymer electrolyte having a multi-layer structure, which comprises a first polymer electrolyte layer and a second polymer electrolyte layer, wherein the EO:Li molar ratio of a poly(ethylene oxide)(PEO)-based polymer and a lithium salt is different between the first and second polymer electrolyte layers. The application of the solid polymer electrolyte of the present invention to the all-solid battery can remarkably reduce the interfacial resistance with lithium and the discharge overvoltage, resulting in a sufficient discharge capacity, and can improve output characteristics and energy density.

Description

다층 구조의 고분자 전해질 및 이를 포함하는 전고체 전지Polymer electrolyte having a multilayer structure and an all-solid-state battery comprising the same
본 출원은 2015년 10월 30일자 한국 특허 출원 제10-2015-0151630호 및 2016년 10월 28일자 한국 특허 출원 제10-2016-0141786호에 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. 10-2015-0151630 filed on October 30, 2015 and Korean Patent Application No. 10-2016-0141786 filed on October 28, 2016. All content disclosed in the literature is included as part of this specification.
본 발명은 다층 구조를 갖는 전고체 전지(All-Solid-State Battery)용 고분자 전해질에 관한 것으로, 보다 상세하게는 폴리에틸렌옥사이드(Poly(ethylene oxide): PEO)계 고분자 및 리튬염의 EO : Li 몰비가 상이한 제1 고분자 전해질층 및 제2 고분자 전해질층을 포함하는 다층 구조의 고분자 전해질에 관한 것이다.The present invention relates to a polymer electrolyte for an all-solid-state battery having a multi-layer structure, and more specifically, the EO: Li molar ratio of a polyethylene oxide (PEO) -based polymer and a lithium salt is A multi-layered polymer electrolyte comprising different first polymer electrolyte layers and second polymer electrolyte layers.
최근 이차 전지는 PC, 비디오 카메라 및 휴대 전화 등의 전원으로서, 혹은 전기 자동차나 전력 저장용 매체의 전원으로서 다양한 용도에서 그 수요가 증가하고 있다. 이차 전지 중에서도 특히 리튬계 이차 전지는 다른 이차 전지보다 용량 밀도가 높고, 고전압에서도 작동이 가능하기 때문에, 소형 경량화를 위한 이차 전지로서 정보 관련 기기나 통신 기기에 사용되고 있고, 최근 전기 자동차나 하이브리드 자동차용의 고출력이면서 고용량인 리튬계 이차 전지의 개발이 진행되고 있다.2. Description of the Related Art In recent years, secondary batteries have been increasing in demand for various applications as power sources for PCs, video cameras, mobile phones, and the like, or as power sources for electric vehicles and power storage media. Among the secondary batteries, especially lithium-based secondary batteries have higher capacity density than other secondary batteries and can operate at high voltage, and thus are used in information-related devices and communication devices as secondary batteries for compact and lightweight, and have recently been used for electric vehicles and hybrid vehicles. The development of high power and high capacity lithium-based secondary batteries is in progress.
통상의 리튬계 이차 전지는 양극(정극, Cathode), 음극(부극, Anode) 및 이들 사이에 개재되는 리튬염을 함유하는 전해질로 구성되며, 이러한 전해질은 비수계 액체 전해질 또는 고체 전해질이 사용된다. 전해질에 비수계 액체 전해질이 사용될 경우에는 전해액이 양극의 내부로 침투하기 때문에, 양극을 구성하는 양극 활물질과 전해질의 계면이 형성되기 쉬워 전기적 성능이 높은 특징이 있다.A typical lithium-based secondary battery is composed of an electrolyte containing a positive electrode (positive electrode, cathode), a negative electrode (negative electrode, anode) and a lithium salt interposed therebetween, and such an electrolyte is a non-aqueous liquid electrolyte or a solid electrolyte. When a non-aqueous liquid electrolyte is used for the electrolyte, since the electrolyte penetrates into the positive electrode, an interface between the positive electrode active material constituting the positive electrode and the electrolyte tends to be formed, and thus has high electrical performance.
그러나, 리튬계 이차 전지는, 액체 전해액에 가연성의 유기 용매를 사용하고 있기 때문에, 단락(Short)에 의한 과전류 등에 기인하여 발생하는 경우가 있는 발화나 파열을 방지하기 위해서, 안전 장치의 부설이 필요해지기도 한다. 또한, 이러한 현상을 방지하기 위해서, 전지 재료의 선택이나 전지 구조의 설계를 행하는 데 있어서 제약을 받거나 하는 경우가 있다.However, since a lithium secondary battery uses a flammable organic solvent in the liquid electrolyte, it is necessary to install a safety device in order to prevent ignition and rupture that may occur due to overcurrent due to a short circuit. It is also built. In addition, in order to prevent such a phenomenon, there may be a restriction in selecting a battery material or designing a battery structure.
따라서, 액체 전해액 대신에, 고체 전해질을 사용하는 전(全)고체형 전지의 개발이 진행되고 있다. 전고체 전지는, 가연성의 유기 용매를 포함하지 않기 때문에, 안전 장치를 간략화할 수 있는 이점이 있어, 제조 비용이나 생산성이 우수한 전지라고 인식되고 있다. 또한, 양극(정극)층 및 음극(부극)층을 포함하는 한 쌍의 전극층과, 이들 전극층 사이에 놓이는 고체 전해질층을 포함하는 접합 구조를 직렬로 적층하는 것이 용이하기 때문에, 안정되면서 고용량이고, 또한 고출력의 전지를 제조할 수 있는 기술로서 기대되고 있다.Therefore, development of the all-solid-state battery which uses a solid electrolyte instead of a liquid electrolyte is advanced. Since an all-solid-state battery does not contain a flammable organic solvent, it has the advantage of simplifying a safety device, and is recognized as a battery excellent in manufacturing cost and productivity. Moreover, since it is easy to stack a junction structure including a pair of electrode layers including an anode (positive electrode) layer and a cathode (negative electrode) layer and a solid electrolyte layer sandwiched between these electrode layers, it is stable and has a high capacity, In addition, it is expected as a technology that can produce a battery of high power.
한편, 전고체 전지에 있어서, 전지 반응을 담당하는 활물질 입자의 입자 사이나, 활물질 입자와 고체 전해질 입자와의 사이의 접촉 저항이, 전지의 내부 저항에 크게 영향을 미치고 있는 것이 알려져있다. 특히, 충방전의 반복에 수반하여, 활물질의 체적 변화가 발생함으로써, 활물질과 고체 전해질이나 도전재 등과의 접촉성이 저하되고, 내부 저항의 증대나 용량의 저하 등이 발생하기 쉬운 경향이 있다. 따라서, 활물질이나 고체 전해질의 입자 사이의 접촉성을 개선하고, 내부 저항의 증대 등을 억제하는 다양한 기술들이 제안되고 있다.On the other hand, in an all-solid-state battery, it is known that the contact resistance between the particles of the active material particles responsible for the battery reaction and between the active material particles and the solid electrolyte particles greatly influence the internal resistance of the battery. In particular, as the volume change of the active material occurs with repeated charge and discharge, the contact between the active material and the solid electrolyte, the conductive material, and the like decreases, and there is a tendency that an increase in internal resistance, a decrease in capacity, and the like tend to occur. Therefore, various techniques have been proposed to improve the contact between the particles of the active material and the solid electrolyte and to suppress the increase in internal resistance.
예컨대, 양극 활물질과 고체 전해질 재료 간의 계면에 주목하여 전고체 전지의 성능을 개선하고자 하는 시도가 있다. 예를 들어, Narumi Ohta 등의 연구논문 "LiNbO3-coated LiCoO2 as cathode material for all solid-state lithium secondary batteries", Electrochemistry Communications 9(2007), 1486 ~ 1490은 LiCoO2(양극 활물질)의 표면에 코팅되는 재료로 LiNbO3(니오브산리튬(Lithium niobate))를 기재하고 있다. 이러한 기술은 상기 LiCoO2의 표면이 LiNbO3로 코팅되어, LiCoO2와 고체 전해질 재료 간의 반응을 억제함으로써, LiCoO2와 상기 고체 전해질 재료 간의 계면저항을 저감시키는 방식으로 고전력 전지를 얻고자 하는 것이다.For example, there is an attempt to improve the performance of an all-solid-state battery by paying attention to the interface between the cathode active material and the solid electrolyte material. For example, Narumi Ohta et al., "LiNbO 3 -coated LiCoO 2 as cathode material for all solid-state lithium secondary batteries", Electrochemistry Communications 9 (2007), 1486 ~ 1490, is applied to the surface of LiCoO 2 (anode active material). LiNbO 3 (Lithium niobate) is described as the material to be coated. This technique is to obtain a high power battery in such a manner as to reduce the interface resistance between the surface of LiCoO 2 is coated with LiNbO 3, LiCoO 2 as solid by suppressing the reaction between the electrolyte material, the solid electrolyte material and LiCoO 2.
또한, 음극 활물질이 고체 전해질 재료와 반응하는 경우, 일반적으로 음극 활물질의 표면 상에 고저항 부분이 형성되어, 음극 활물질과 고체 전해질 재료 간의 계면저항이 증가하게 된다. 이러한 문제점을 해결하기 위하여, 일본 공개특허공보 제2004-206942호는 제1 고체 전해질과 화학적으로 반응하지 않고 제1 고체 전해질층(황화물계 고체 전해질 재료) 보다 낮은 이온 전도성을 갖는 제2 고체 전해질층이 상기 제1 고체 전해질층과 금속 리튬으로 제조된 음극 사이에 형성되는 전고체 전지를 개시하고 있다. 이는 낮은 이온 전도성을 갖는 제2 고체 전해질층의 형성을 통하여 제1 고체 전해질층과 금속 리튬 간의 반응을 억제하고자 하는 것이다.In addition, when the negative electrode active material reacts with the solid electrolyte material, a high resistance portion is generally formed on the surface of the negative electrode active material, thereby increasing the interface resistance between the negative electrode active material and the solid electrolyte material. In order to solve this problem, Japanese Laid-Open Patent Publication No. 2004-206942 discloses a second solid electrolyte layer which does not chemically react with the first solid electrolyte and has lower ion conductivity than the first solid electrolyte layer (sulfide-based solid electrolyte material). Disclosed is an all-solid-state battery formed between the first solid electrolyte layer and a cathode made of metallic lithium. This is to suppress the reaction between the first solid electrolyte layer and the metal lithium through the formation of a second solid electrolyte layer having low ion conductivity.
그러나 이러한 전고체 전지의 성능을 개선하고자 하는 시도들은 양극 또는 음극 활물질과 고체 전해질 재료 간의 계면저항을 충분히 낮추지 못하여 고출력, 고용량의 전지의 제조에 적합하지 않은 실정이다.However, attempts to improve the performance of such all-solid-state batteries do not reduce the interfacial resistance between the positive electrode or negative electrode active material and the solid electrolyte material, which is not suitable for the production of high-output, high-capacity batteries.
[선행기술문헌][Preceding technical literature]
[특허문헌][Patent Documents]
(특허문헌 1) 대한민국 공개특허공보 제2012-0092918호 "리튬 이차 전지용 고분자 복합 전해질 및 이를 포함하는 리튬 이차 전지"(Patent Document 1) Korean Unexamined Patent Publication No. 2012-0092918 "Polymer composite electrolyte for lithium secondary battery and lithium secondary battery comprising same"
(특허문헌 2) 일본 공개특허공보 제2004-206942호 "전고체 리튬전지"(Patent Document 2) Japanese Unexamined Patent Publication No. 2004-206942 "All-solid-state lithium battery"
[비특허문헌][Non-Patent Documents]
(비특허문헌 1) Qian, Jiangfeng, et al. "High rate and stable cycling of lithium metal anode." Nature communications 6(2015)(Non-Patent Document 1) Qian, Jiangfeng, et al. "High rate and stable cycling of lithium metal anode." Nature communications 6 (2015)
(비특허문헌 2) "LiNbO3-coated LiCoO2 as cathode material for all solid-state lithium secondary batteries", Electrochemistry Communications 9(2007), 1486 ~ 1490(Non-Patent Document 2) "LiNbO3-coated LiCoO2 as cathode material for all solid-state lithium secondary batteries", Electrochemistry Communications 9 (2007), 1486-1490.
고체 고분자 전해질을 적용한 전고체 전지는 상온에서는 물론 60℃ 혹은 80℃에서도 충분한 출력 혹은 용량이 발현되기가 힘들다. 이러한 이유로는 첫째, 고분자 전해질의 낮은 이온 전도도, 둘째, 리튬과 고분자 전해질 사이의 계면저항을 들 수 있다. 고분자 전해질의 이온 전도도를 해결하기 위해 그동안 많은 노력이 있어 왔으나 획기적인 이온 전도도의 향상은 없었으며, 고체 고분자 전해질의 한계로 지적되어 왔다.An all-solid-state battery to which a solid polymer electrolyte is applied is hard to express sufficient output or capacity at room temperature but also at 60 ° C or 80 ° C. The reasons for this are firstly low ionic conductivity of the polymer electrolyte and secondly, interfacial resistance between lithium and the polymer electrolyte. Although many efforts have been made to solve the ionic conductivity of the polymer electrolyte, there has been no significant improvement in ionic conductivity, and it has been pointed out as a limitation of the solid polymer electrolyte.
한편, 선행 문헌에 따르면, 액체 전해질과 리튬 금속을 사용하는 전지에서 고농도의 전해액이 리튬과의 반응성이 낮으며, 계면저항 역시 낮다는 연구가 보고된 바 있다(Qian, Jiangfeng, et al. "High rate and stable cycling of lithium metal anode." Nature communications 6(2015)). 본 발명자들은 이에 착안하여 리튬과 고체 고분자 전해질 간의 계면저항을 낮추기 위해 고농도의 리튬염을 사용한 고분자 전해질을 전고체 전지에 적용함으로써 본 발명을 완성하기에 이르렀다.On the other hand, according to the prior literature, studies have been reported that a high concentration of electrolytes have low reactivity with lithium and low interfacial resistance in a battery using a liquid electrolyte and lithium metal (Qian, Jiangfeng, et al. "High rate and stable cycling of lithium metal anode. "Nature communications 6 (2015)). In light of this, the inventors have completed the present invention by applying a polymer electrolyte using a high concentration of lithium salt to an all-solid-state battery in order to lower the interfacial resistance between lithium and a solid polymer electrolyte.
따라서 본 발명의 목적은, 리튬과 고분자 전해질 사이의 계면저항을 현저히 낮춘 전고체 전지용 고분자 전해질을 제공하고자 하는 것이다.Accordingly, an object of the present invention is to provide a polymer electrolyte for an all-solid-state battery which significantly lowers the interface resistance between lithium and a polymer electrolyte.
본 발명은 폴리에틸렌옥사이드(Poly(ethylene oxide): PEO)계 고분자 및 리튬염의 EO : Li의 몰비가 1 : 1 ~ 7 : 1인 제1 고분자 전해질층; 및The present invention provides a polymer electrolyte layer having a molar ratio of EO: Li of a polyethylene oxide (PEO) -based polymer and a lithium salt of 1: 1 to 7: 1; And
폴리에틸렌옥사이드계 고분자 및 리튬염의 EO : Li의 몰비가 30 : 1 ~ 8 : 1 인 제2 고분자 전해질층;A second polymer electrolyte layer having a molar ratio of EO: Li of the polyethylene oxide polymer and the lithium salt of 30: 1 to 8: 1;
을 포함하는 다층 구조의 전고체 전지용 고분자 전해질을 제공한다.It provides a polymer electrolyte for an all-solid-state battery comprising a multi-layer structure.
이때, 상기 제1 고분자 전해질층의 두께는 1 ~ 5 ㎛일 수 있다.In this case, the thickness of the first polymer electrolyte layer may be 1 to 5 μm.
이때, 상기 제2 고분자 전해질층의 두께는 5 ~ 50 ㎛일 수 있다.At this time, the thickness of the second polymer electrolyte layer may be 5 ~ 50 ㎛.
이때, 상기 폴리에틸렌옥사이드계 고분자의 중량평균분자량(Mw)이 1,000,000 내지 8,000,000일 수 있다.In this case, the weight average molecular weight (Mw) of the polyethylene oxide polymer may be 1,000,000 to 8,000,000.
이때, 상기 리튬염은 LiCl, LiBr, LiI, LiClO4, LiBF4, LiB10Cl10, LiPF6, LiCF3SO3, LiCF3CO2, LiAsF6, LiSbF6, LiAlCl4, CH3SO3Li, CF3SO3Li, LiSCN, LiC(CF3SO2)3, (CF3SO2)2NLi, (FSO2)2NLi, 클로로 보란 리튬, 저급 지방족 카르본산 리튬, 4-페닐 붕산 리튬, 이미드 및 이들의 조합으로부터 선택된 1종을 포함할 수 있다.At this time, 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 , LiAsF 6 , LiSbF 6 , LiAlCl 4 , CH 3 SO 3 Li , CF 3 SO 3 Li, LiSCN, LiC (CF 3 SO 2 ) 3 , (CF 3 SO 2 ) 2 NLi, (FSO 2 ) 2 NLi, chloroborane lithium, lower aliphatic carbonate, lithium 4-phenyl borate, It may include one selected from imides and combinations thereof.
이때, 상기 제2 고분자 전해질층은 가교성 단량체에 의해 가교되어 반 상호침투 고분자 네트워크(semi-IPN: semi-Interpenetrating Polymer Networks)를 형성할 수 있다.In this case, the second polymer electrolyte layer may be cross-linked by a crosslinkable monomer to form a semi-interpenetrating polymer network (semi-IPN).
이때, 상기 가교성 단량체는 ―(CH2―CH2―O)―반복 단위를 포함할 수 있다.In this case, the crosslinkable monomer may include a — (CH 2 —CH 2 —O) —repeating unit.
이때, 상기 가교성 단량체는 말단에 2개 내지 8개의 알킬렌성 불포화 결합을 포함할 수 있다.In this case, the crosslinkable monomer may include 2 to 8 alkylenically unsaturated bonds at the terminals.
이때, 상기 가교성 단량체는 상기 폴리에틸렌옥사이드계 고분자 및 리튬염에 대하여 5 ~ 50 wt%로 포함될 수 있다.In this case, the crosslinkable monomer may be included in an amount of 5 to 50 wt% based on the polyethylene oxide polymer and the lithium salt.
또한, 본 발명은 양극, 음극 및 이들 사이에 개재되는 고체 고분자 전해질을 포함하여 구성되는 전(全)고체 전지에 있어서, In addition, the present invention is an all-solid-state battery comprising a positive electrode, a negative electrode and a solid polymer electrolyte interposed therebetween,
상기 고체 고분자 전해질은 상기 다층 구조의 전고체 전지용 고분자 전해질인 것을 특징으로 하는 전고체 전지를 제공한다.The solid polymer electrolyte provides an all-solid-state battery, which is a polymer electrolyte for an all-solid-state battery having the multilayer structure.
이때, 상기 제1 고분자 전해질층은 상기 음극에 대면하여 배치될 수 있다.In this case, the first polymer electrolyte layer may be disposed to face the cathode.
본 발명의 고체 고분자 전해질을 전고체 전지에 적용하면, 리튬과의 계면저항 및 방전 과전압이 현저히 감소하여, 결과적으로 충분한 방전 용량이 구현되며, 출력 특성 및 에너지 밀도를 개선시킬 수 있다.When the solid polymer electrolyte of the present invention is applied to an all-solid-state battery, the interfacial resistance with lithium and the discharge overvoltage are significantly reduced, resulting in sufficient discharge capacity and improved output characteristics and energy density.
도 1은 비교예 1에 의한 리튬 시메트릭 전지의 계면저항을 나타낸 그래프이다.1 is a graph showing the interfacial resistance of a lithium metric battery according to Comparative Example 1. FIG.
도 2는 실시예 1에 의한 리튬 시메트릭 전지의 계면저항을 나타낸 그래프이다.2 is a graph showing the interfacial resistance of the lithium symmetric battery according to Example 1. FIG.
도 3은 비교예 2(a)와 실시예 2(b)에 의한 전고체 전지의 단면 비교도이다.3 is a cross-sectional comparison diagram of the all-solid-state battery according to Comparative Example 2 (a) and Example 2 (b).
도 4는 비교예 2(a)와 실시예 2(b)에 의한 전고체 전지의 방전 용량을 비교한 그래프이다.4 is a graph comparing discharge capacities of all-solid-state batteries according to Comparative Example 2 (a) and Example 2 (b).
본 발명의 리튬 이차전지로서, 전고체 전지에 적용되는 고체 고분자 전해질은 폴리에틸렌옥사이드(Poly(ethylene oxide): PEO)계 고분자 및 리튬염을 포함하며, 폴리에틸렌옥사이드계 고분자 및 리튬염의 EO : Li 몰비가 상이한 제1 고분자 전해질층 및 제2 고분자 전해질층을 포함하는 다층 구조의 고분자 전해질을 개시한다. 이하 본 발명의 고분자 전해질의 구성 요소별로 상세히 설명한다.As the lithium secondary battery of the present invention, the solid polymer electrolyte applied to an all-solid-state battery includes a polyethylene oxide (PEO) -based polymer and a lithium salt, and the EO: Li molar ratio of the polyethylene oxide-based polymer and the lithium salt is A multi-layered polymer electrolyte comprising a different first polymer electrolyte layer and a second polymer electrolyte layer is disclosed. Hereinafter, each component of the polymer electrolyte of the present invention will be described in detail.
제1 고분자 전해질층First polymer electrolyte layer
본 발명에서 제1 고분자 전해질층은 계면저항을 낮추기 위해 적용되는 것으로, 폴리에틸렌옥사이드계 고분자 및 리튬염의 EO : Li의 몰비가 1 : 1 ~ 7 : 1 범위 내에서 선택하여 제조한다. 상기와 같이 리튬염을 높은 비율로 도핑(Dopping)하여 1 ~ 5 ㎛ 두께로 박막화하여 적용하면, 이온 전도도는 다소 낮아지나, 계면저항을 현저히 낮출 수 있다.In the present invention, the first polymer electrolyte layer is applied to lower the interfacial resistance, and the EO: Li molar ratio of the polyethylene oxide polymer and the lithium salt is selected and prepared within the range of 1: 1 to 7: 1. As described above, when the lithium salt is doped at a high rate and thinned to a thickness of 1 to 5 μm, the ion conductivity is slightly lowered, but the interface resistance can be significantly lowered.
제2 고분자 전해질층Second polymer electrolyte layer
본 발명에서 제2 고분자 전해질층은 기계적 강도를 높여 덴드라이트(Dendrite) 생성으로 인한 현상을 방지하기 위해 적용되는 것으로, 폴리에틸렌옥사이드계 고분자 및 리튬염의 EO : Li의 몰비가 30 : 1 ~ 8 : 1 범위 내에서 선택하여 제조한다. 이때 제2 고분자 전해질층의 두께는 5 ~ 50 ㎛일 수 있다.In the present invention, the second polymer electrolyte layer is applied to prevent the phenomenon caused by the generation of dendrite by increasing the mechanical strength, and the molar ratio of EO: Li of the polyethylene oxide polymer and the lithium salt is 30: 1 to 8: 1 It selects and manufactures in the range. In this case, the thickness of the second polymer electrolyte layer may be 5 to 50 μm.
또한 상기 제2 고분자 전해질층은 가교성 단량체에 의해 가교되어 반 상호침투 고분자 네트워크(semi-Interpenetrating Polymer Networks, 이하 semi-IPN) 구조를 형성할 수 있다. 이러한 semi-IPN 구조는 고체 고분자 전해질의 강도를 높일 수 있으며, 이러한 강도가 높을수록 전극 표면에서의 리튬 덴드라이트의 발생을 물리적으로 억제할 수 있다. 이때 폴리에틸렌옥사이드계 고분자의 중량평균분자량(Mw)은 1,000,000 내지 8,000,000 범위 내로 상대적으로 고분자량을 적용하면, 보다 치밀한 semi-IPN 구조를 형성할 수 있다.In addition, the second polymer electrolyte layer may be crosslinked by a crosslinkable monomer to form a semi-interpenetrating polymer network (semi-IPN) structure. The semi-IPN structure can increase the strength of the solid polymer electrolyte, and the higher the strength, the more physically it can suppress the generation of lithium dendrites on the electrode surface. At this time, the weight average molecular weight (Mw) of the polyethylene oxide-based polymer may form a more dense semi-IPN structure when a relatively high molecular weight is applied within the range of 1,000,000 to 8,000,000.
상기 가교성 단량체는 2관능 이상의 다관능 단량체가 사용될 수 있으며, ―(CH2―CH2―O)―반복 단위를 포함하고, 양 말단에 중합 가능한 2개 내지 8개 범위 내의 알킬렌성 불포화 결합을 포함하는 것이 바람직하다. 상기 알킬렌성 불포화 결합이란 적어도 하나의 탄소-탄소 이중결합 또는 삼중결합을 포함하는 탄화수소기로서 에테닐기, 1-프로페닐기, 2-프로페닐기, 2-메틸-1-프로페닐기, 1-부테닐기, 2-부테닐기, 에티닐기, 1-프로피닐기, 1-부티닐기, 2-부티닐기 등을 포함하나 이들로 한정되지 않는다. 이러한 알킬렌성 불포화 결합이 가교점으로 작용하여 중합 공정을 통해 상기 폴리에틸렌옥사이드계 고분자를 가교화시킴으로써 semi-IPN 구조를 형성하게 하는 것이다.The crosslinkable monomer may be a bifunctional or more than one polyfunctional monomer, and may include a-(CH 2 -CH 2 -O) -repeat unit, and may form an alkylenically unsaturated bond within the range of 2 to 8 polymerizable at both ends. It is preferable to include. The alkylenically unsaturated bond is a hydrocarbon group including at least one carbon-carbon double bond or triple bond, an ethenyl group, 1-propenyl group, 2-propenyl group, 2-methyl-1-propenyl group, 1-butenyl group, 2-butenyl group, ethynyl group, 1-propynyl group, 1-butynyl group, 2-butynyl group, and the like, but are not limited thereto. Such alkylenically unsaturated bonds act as a crosslinking point to form a semi-IPN structure by crosslinking the polyethylene oxide polymer through a polymerization process.
예컨대, 상기 가교성 단량체로는 폴리에틸렌글리콜디아크릴레이트(Poly(ethylene glycol) diacrylate: PEGDA), 폴리에틸렌글리콜디메타크릴레이트(Poly(ethylene glycol) dimethacrylate: PEGDMA), 폴리프로필렌글리콜디아크릴레이트(Poly(propylene glycol) diacrylate: PPGDA), 폴리프로필렌글리콜디메타크릴레이트(Poly(propylene glycol) dimethacrylate: PPGDMA) 및 이들의 조합으로부터 선택될 수 있으며, 바람직하게는 폴리에틸렌글리콜디아크릴레이트(PEGDA)를 사용할 수 있다.For example, the crosslinkable monomer may include polyethylene glycol diacrylate (PEGDA), polyethylene glycol dimethacrylate (PEGDMA), polypropylene glycol diacrylate (Poly ( propylene glycol diacrylate: PPGDA), poly (propylene glycol) dimethacrylate (PPGDMA) and combinations thereof, and preferably polyethylene glycol diacrylate (PEGDA). .
또한 가교성 단량체는 상기 폴리에틸렌옥사이드계 고분자 중량 대비 5 ~ 50 wt%로 포함되는 것이 본 발명의 목적에 맞는 semi-IPN 구조를 형성하는데 바람직하다.In addition, the crosslinkable monomer is preferably included in the range of 5 to 50 wt% based on the weight of the polyethylene oxide-based polymer to form a semi-IPN structure suitable for the purpose of the present invention.
상기 가교성 단량체가 상기 폴리에틸렌옥사이드계 고분자 사이에서 가교화되는 방법에 있어서는 특별히 제한은 없으나, 바람직하게는 열개시제를 첨가한 후, 적절한 온도조건을 유지하면서 가교시킬 수 있다. 이때 열개시제로는 벤조일 퍼옥사이드(Benzoyl peroxide: BPO), 또는 아조비시소부티로니트릴(Azobisisobutyronitrile: AIBN)가 적용 가능하다.There is no restriction | limiting in particular in the method of the said crosslinkable monomer crosslinking between the said polyethylene oxide type polymers, Preferably, after adding a thermal initiator, it can crosslinking, maintaining suitable temperature conditions. In this case, benzoyl peroxide (BPO) or azobisisobutyronitrile (AIBN) may be applied as the thermal initiator.
본 발명에 따른 제1 고분자 전해질층 및 제2 고분자 전해질층에 공통적으로 적용되는 리튬염은 리튬 이온으로 해리되어 제1 고분자 전해질층 및 제2 고분자 전해질층 내부에 침투하여 자유롭게 이동할 수 있다. 이때 리튬 이온의 공급원으로서 기본적인 리튬 전지의 작동을 가능하게 하며, 이러한 리튬염으로는 리튬 전지에서 통상적으로 사용되는 것이라면 모두 다 사용가능하나, 바람직하게는 LiCl, LiBr, LiI, LiClO4, LiBF4, LiB10Cl10, LiPF6, LiCF3SO3, LiCF3CO2, LiAsF6, LiSbF6, LiAlCl4, CH3SO3Li, CF3SO3Li, LiSCN, LiC(CF3SO2)3, (CF3SO2)2NLi, (FSO2)2NLi, 클로로 보란 리튬, 저급 지방족 카르본산 리튬, 4-페닐 붕산 리튬, 이미드 및 이들의 조합으로부터 선택된 1종을 포함할 수 있으나, 보다 바람직하게는 (FSO2)2NLi로 표시되는 LiFSI(Lithium bis(fluorosulfonyl)imide)가 가능하다.Lithium salts commonly applied to the first polymer electrolyte layer and the second polymer electrolyte layer according to the present invention may be dissociated into lithium ions to penetrate into the first polymer electrolyte layer and the second polymer electrolyte layer and move freely. At this time, it is possible to operate a basic lithium battery as a source of lithium ions, and any lithium salt can be used as long as it is commonly used in lithium batteries, but preferably LiCl, LiBr, LiI, LiClO 4 , LiBF 4 , LiB 10 Cl 10 , LiPF 6 , LiCF 3 SO 3 , LiCF 3 CO 2 , LiAsF 6 , LiSbF 6 , LiAlCl 4 , CH 3 SO 3 Li, CF 3 SO 3 Li, LiSCN, LiC (CF 3 SO 2 ) 3 , (CF 3 SO 2 ) 2 NLi, (FSO 2 ) 2 NLi, chloroborane lithium, lower aliphatic lithium carbonate, lithium 4-phenyl borate, imide and combinations thereof, but more preferably Lithium bis (fluorosulfonyl) imide (LiFSI), preferably represented by (FSO 2 ) 2 NLi, is possible.
본 발명의 제1 고분자 전해질층 또는 제2 고분자 전해질층의 제조 방법은 본 발명에서 한정하지 않으며, 공지된 바에 따라 습식 또는 건식의 방법으로 혼합 및 성형 공정이 사용될 수 있다. 또한 본 발명의 고체 고분자 전해질의 두께는 1 ~ 50 ㎛ 범위 내에서 선택적으로 제조할 수 있다.The manufacturing method of the first polymer electrolyte layer or the second polymer electrolyte layer of the present invention is not limited in the present invention, and a mixing and molding process may be used by a wet or dry method as is known. In addition, the thickness of the solid polymer electrolyte of the present invention may be selectively prepared within the range of 1 to 50 ㎛.
이하 양극과 음극 사이에 개재되는 본 발명의 고체 고분자 전해질을 포함하는 전고체 전지로서, 상기 제1 고분자 전해질층이 음극과 대면하여 계면저항이 현저히 저하된 전고체 전지에 관하여 설명한다.Hereinafter, an all-solid-state battery including the solid polymer electrolyte of the present invention interposed between a positive electrode and a negative electrode, will be described an all-solid-state battery in which the first polymer electrolyte layer faces the negative electrode and the interface resistance is significantly reduced.
전고체 전지All-solid-state battery
전극 활물질은 본 발명에서 제시하는 전극이 양극일 경우에는 양극 활물질이, 음극일 경우에는 음극 활물질이 사용될 수 있다. 이때 각 전극 활물질은 종래 전극에 적용되는 활물질이면 어느 것이든 가능하고, 본 발명에서 특별히 한정하지 않는다.The electrode active material may be a positive electrode active material when the electrode proposed in the present invention is a positive electrode, a negative electrode active material when the negative electrode. At this time, each electrode active material can be any active material applied to a conventional electrode, and is not particularly limited in the present invention.
본 발명에 사용되는 양극 또는 음극 활물질은 의도된 전고체 전지의 전도 이온의 타입에 따라 변한다. 예를 들어, 본 발명에 따른 전고체 전지가 전고체 리튬 2차 전지인 경우, 상기 양극 또는 음극 활물질은 리튬 이온들을 흡장(Occludes)하거나 방출(Releases)한다. 또한, 본 발명에 사용되는 양극 또는 음극 활물질은 통상적으로 상술된 고체 전해질 재료와 반응할 수 있어 고저항 부분을 형성하게 된다.The positive electrode or negative electrode active material used in the present invention varies depending on the type of conductive ions of the intended all-solid-state battery. For example, when the all-solid-state battery according to the present invention is an all-solid lithium secondary battery, the positive or negative electrode active material occludes or releases lithium ions. In addition, the positive electrode or negative electrode active material used in the present invention can generally react with the solid electrolyte material described above to form a high resistance portion.
양극 활물질은 리튬 이차전지의 용도에 따라 달라질 수 있으며, 구체적인 조성은 공지된 물질을 사용한다. 일례로, 리튬-인산-철계 화합물, 리튬 코발트계 산화물, 리튬 망간계 산화물, 리튬 구리 산화물, 리튬 니켈계 산화물 및 리튬 망간 복합 산화물, 리튬-니켈-망간-코발트계 산화물로 이루어진 군으로부터 선택된 어느 하나의 리튬 전이금속 산화물을 들 수 있다. 보다 구체적으로는, Li1 + aM(PO4-b)Xb으로 표시되는 리튬 금속 인산화물 중에서, M은 제 2 내지 12 족의 금속 중에서 선택되는 1종 이상이며, X는 F, S 및 N 중에서 선택된 1종 이상으로서, -0.5≤a≤+0.5, 및 0≤b≤0.1인 것이 바람직하다.The positive electrode active material may vary depending on the use of the lithium secondary battery, and the specific composition uses a known material. For example, any one selected from the group consisting of lithium-phosphate-iron compound, lithium cobalt-based oxide, lithium manganese-based oxide, lithium copper oxide, lithium nickel-based oxide and lithium manganese composite oxide, lithium-nickel-manganese-cobalt-based oxide And lithium transition metal oxides. More specifically, in the lithium metal phosphate represented by Li 1 + a M (PO 4-b ) X b , M is at least one selected from metals of Groups 2 to 12, and X is F, S and As at least 1 type selected from N, it is preferable that they are -0.5 <= <= 0.5, and 0 <= b <= 0.1.
이때 음극 활물질은 리튬 금속, 리튬 합금, 리튬 금속 복합 산화물, 리튬 함유 티타늄 복합 산화물(LTO) 및 이들의 조합으로 이루어진 군에서 선택된 1종이 가능하다. 이때 리튬 합금은 리튬과 Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Ba, Ra, Al 및 Sn으로부터 선택되는 적어도 하나의 금속으로 이루어진 합금을 사용할 수 있다. 또한, 리튬 금속 복합 산화물은 리튬과 Si, Sn, Zn, Mg, Cd, Ce, Ni 및 Fe로 이루어진 군으로부터 선택된 어느 하나의 금속(Me) 산화물(MeOx)이고, 일례로 LixFe2O3(0<x≤1) 또는 LixWO2(0<x≤1)일 수 있다.In this case, the negative electrode active material may be one selected from the group consisting of lithium metal, lithium alloy, lithium metal composite oxide, lithium-containing titanium composite oxide (LTO), and combinations thereof. At this time, the lithium alloy may be an alloy consisting of lithium and at least one metal selected from Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Ba, Ra, Al and Sn. In addition, the lithium metal composite oxide is any one metal (Me) oxide (MeO x ) selected from the group consisting of lithium and Si, Sn, Zn, Mg, Cd, Ce, Ni, and Fe, for example, Li x Fe 2 O 3 (0 <x ≦ 1) or Li x WO 2 (0 <x ≦ 1).
이때 필요한 경우 상기 활물질에 더하여 도전재(Conducting material), 고분자 전해질, 바인더, 충진제 등을 더욱 첨가할 수 있으며, 도전재는 당해 전지에 화학적 변화를 유발하지 않으면서 도전성을 가진 것이라면 특별히 제한되는 것은 아니며, 예컨대, 그라파이트; 카본블랙, 아세틸렌 블랙, 케첸 블랙, 채널 블랙, 퍼니스 블랙, 램프 블랙, 서머 블랙 등의 카본블랙; 탄소 섬유나 금속 섬유 등의 도전성 섬유; 불화 카본, 알루미늄, 니켈 분말 등의 금속 분말; 산화아연, 티탄산 칼륨 등의 도전성 위스키; 산화 티탄 등의 도전성 금속 산화물; 폴리페닐렌 유도체 등의 도전성 소재 등이 사용될 수 있다. 시판되고 있는 도전재의 구체적인 예로는 아세틸렌 블랙 계열인 쉐브론 케미칼 컴퍼니(Chevron Chemical Company)나 덴카 블랙(Denka Singapore Private Limited), 걸프 오일 컴퍼니(Gulf Oil Company) 제품, 케첸 블랙(Ketjenblack), EC 계열 아르막 컴퍼니(Armak Company) 제품, 불칸(Vulcan) XC-72 캐보트 컴퍼니(Cabot Company) 제품 및 수퍼피(Super P; Timcal 사 제품) 등이 사용될 수 있다.In this case, if necessary, a conductive material, a polymer electrolyte, a binder, a filler, and the like may be further added to the active material, and the conductive material is not particularly limited as long as it has conductivity without causing chemical changes to the battery. For example, graphite; Carbon blacks such as carbon 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 powder, aluminum powder and nickel powder; Conductive whiskeys such as zinc oxide and potassium titanate; Conductive metal oxides such as titanium oxide; Conductive materials such as polyphenylene derivatives and the like can be used. Specific examples of commercially available conductive materials include Chevron Chemical Company, Denka Singapore Private Limited, Gulf Oil Company, Ketjenblack and EC Armak, which are acetylene black series. Company (Armak Company), Vulcan XC-72 Cabot Company, Super P (manufactured by Timcal), and the like can be used.
상기 바인더는 활물질과 도전재 등의 결합과 집전체에 대한 결합에 조력하는 성분으로서, 통상적으로 전극 활물질을 포함하는 혼합물 전체 중량을 기준으로 1 ~ 50 wt%로 첨가된다. 이러한 바인더의 예로는, 폴리불화비닐리덴, 폴리비닐알코올, 카르복시메틸셀룰로우즈(CMC), 전분, 히드록시프로필셀룰로우즈, 재생 셀룰로오즈, 폴리비닐피롤리돈, 테트라플루오로에틸렌, 폴리에틸렌, 폴리프로필렌, 에틸렌-프로필렌-디엔 테르 폴리머(EPDM), 술폰화 EPDM, 스티렌 브티렌 고무, 불소 고무, 다양한 공중합제 등을 들 수 있다.The binder is a component that assists in bonding the active material and the conductive material to the current collector, and is generally added in an amount of 1 to 50 wt% based on the total weight of the mixture including the electrode active material. Examples of such binders include polyvinylidene fluoride, polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene, poly Propylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene butylene rubber, fluorine rubber, various copolymers, and the like.
상기 충진제는 당해 전지에 화학적 변화를 유발하지 않으면서 섬유상 재료라면 특별히 제한되는 것은 아니며, 예를 들어, 폴리에틸렌, 폴리프로필렌 등의 올리핀계 중합제; 유리섬유, 탄소섬유 등의 섬유상 물질이 사용된다.The filler is not particularly limited as long as it is a fibrous material without causing chemical change in the battery. Examples of the filler include olefinic polymers such as polyethylene and polypropylene; Fibrous materials, such as glass fiber and carbon fiber, are used.
전지의 충방전 작동시, 상기 전극 활물질과 상기 고체 고분자 전해질 재료 간의 계면에 고저항 부분이 생성된다. 이에 따라, 본 발명에 따른 제1 고분자 전해질층 및 제2 고분자 전해질층이 전고체 전지를 형성하는데 사용되는 경우, 상기 전극 활물질과 상기 고체 전해질 재료 간의 계면을 가로지르는 이온들의 이동에 대한 계면저항을 저감시킬 수 있게 되므로, 출력에 있어서의 감소를 억제할 수 있게 된다.During charge and discharge operation of the battery, a high resistance portion is created at the interface between the electrode active material and the solid polymer electrolyte material. Accordingly, when the first polymer electrolyte layer and the second polymer electrolyte layer according to the present invention are used to form an all-solid-state battery, the interfacial resistance to movement of ions across the interface between the electrode active material and the solid electrolyte material is reduced. Since it becomes possible to reduce, it becomes possible to suppress the reduction in output.
상기 제1 고분자 전해질층은 음극에 대면하여 배치되며, 그 위에 제2 고분자 전해질층이 형성되고, 그 위에 양극이 형성되는 것이 바람직하다. 만약 상기 제1 및 제2 고분자 전해질층의 적층 순서가 반대가 되면 전지의 저항이 증가하여 방전용량이 저하될 수 있어 바람직하지 못하다.The first polymer electrolyte layer is disposed to face the negative electrode, and a second polymer electrolyte layer is formed thereon, and an anode is formed thereon. If the stacking order of the first and second polymer electrolyte layers is reversed, the resistance of the battery may increase and the discharge capacity may decrease, which is not preferable.
또한 상기 폴리에틸렌옥사이드계 고분자 및 리튬염의 EO : Li 몰비가 상이한 두 개의 고분자 전해질층을 사용하는 것, 즉 폴리에틸렌옥사이드계 고분자 및 리튬염의 EO : Li의 몰비가 1 : 1 ~ 7 : 1인 상기 제1 고분자 전해질층 및 폴리에틸렌옥사이드계 고분자 및 리튬염의 EO : Li의 몰비가 30 : 1 ~ 8 : 1인 상기 제2 고분자 전해질층을 동시에 적용하는 것이 바람직하다. 만약 제1 고분자 전해질층이 상기 범위를 벗어나는 경우, 계면저항이 증가하여 방전용량이 저하될 수 있어 바람직하지 못하며, 제2 고분자 전해질층이 상기 범위를 벗어나는 경우, 전해질-분리막 층의 저항이 증가하여 방전 용량이 저하될 수 있어 바람직하지 못하다.In addition, using two polymer electrolyte layers having different EO: Li molar ratios of the polyethylene oxide polymer and the lithium salt, that is, the first ratio wherein the molar ratio of EO: Li of the polyethylene oxide polymer and the lithium salt is from 1: 1 to 7: 1 It is preferable to simultaneously apply the polymer electrolyte layer, the polyethylene oxide polymer and the second polymer electrolyte layer having a molar ratio of EO: Li of lithium salt of 30: 1 to 8: 1. If the first polymer electrolyte layer is out of the above range, the interfacial resistance may increase and the discharge capacity may be lowered, and if the second polymer electrolyte layer is out of the above range, the resistance of the electrolyte-separation membrane layer may increase. Discharge capacity may be lowered, which is undesirable.
전고체 전지의 제조는 전극 및 고체 전해질을 분말 상태로 제조 후 이를 소정의 몰드에 투입 후 프레스하는 건식 압축 공정, 또는 활물질, 용매 및 바인더를 포함하는 슬러리 조성물 형태로 제조 후 코팅 후 건조하는 슬러리 코팅 공정을 통해 제조되고 있다. 상기한 구성을 갖는 전고체 전지의 제조는 본 발명에서 특별히 한정하지 않으며, 공지의 방법이 사용될 수 있다.The manufacture of an all-solid-state battery is a dry compression process in which an electrode and a solid electrolyte are prepared in powder form, and then put into a predetermined mold and pressed, or a slurry coating is prepared after coating and drying in the form of a slurry composition containing an active material, a solvent, and a binder. It is manufactured through the process. The production of the all-solid-state battery having the above configuration is not particularly limited in the present invention, and a known method can be used.
일례로, 양극 및 음극 사이에 고체 전해질을 배치시킨 후 이를 압축 성형하여 셀을 조립한다. 상기 조립된 셀은 외장재 내에 설치한 후 가열 압축 등에 의해 봉지한다. 외장재로는 알루미늄, 스테인레스 등의 라미네이트 팩, 원통형이나 각형의 금속제 용기가 매우 적합하다.In one example, a solid electrolyte is disposed between the positive electrode and the negative electrode and then compression molded to assemble the cell. The assembled cell is installed in an outer packaging material and sealed by heat compression. As the exterior material, laminate packs such as aluminum and stainless steel and cylindrical or rectangular metal containers are very suitable.
전극 슬러리를 집전체 상에 코팅하는 방법은, 전극 슬러리를 집전체 위에 분배시킨 후 닥터 블레이드(Doctor blade) 등을 사용하여 균일하게 분산시키는 방법, 다이 캐스팅(Die casting), 콤마 코팅(Comma coating), 스크린 프린팅(Screen printing) 등의 방법 등을 들 수 있다. 또한, 별도의 기재(Substrate) 위에 성형한 후 프레싱(Pressing) 또는 라미네이션(Lamination) 방법에 의해 전극 슬러리를 집전체와 접합시킬 수도 있다. 이때 슬러리 용액의 농도, 또는 코팅 횟수 등을 조절하여 최종적으로 코팅되는 코팅 두께를 조절할 수 있다.The method of coating the electrode slurry on the current collector is a method of distributing the electrode slurry on the current collector and then uniformly dispersing it using a doctor blade or the like, die casting, comma coating. , Screen printing, and the like. In addition, the electrode slurry may be bonded to the current collector by pressing or lamination after molding on a separate substrate. At this time, by adjusting the concentration of the slurry solution, or the number of coating, it is possible to control the coating thickness to be finally coated.
건조 공정은, 금속 집전체에 코팅된 슬러리를 건조하기 위하여 슬러리 내의 용매 및 수분을 제거하는 과정으로, 사용하는 용매에 따라 달라질 수 있다. 일례로, 50 ~ 200℃의 진공 오븐에서 수행한다. 건조 방법으로는, 예를 들어 온풍, 열풍, 저습풍에 의한 건조, 진공 건조, (원)적외선이나 전자선 등의 조사에 의한 건조법을 들 수 있다. 건조 시간에 대해서는 특별히 한정되지 않지만, 통상적으로 30초 내지 24시간의 범위에서 행해진다.The drying process is a process of removing the solvent and water in the slurry to dry the slurry coated on the metal current collector, and may vary depending on the solvent used. In one example, it is carried out in a vacuum oven at 50 ~ 200 ℃. As a drying method, the drying method by irradiation with warm air, hot air, low humidity wind, vacuum drying, (far) infrared rays, an electron beam, etc. are mentioned, for example. Although it does not specifically limit about drying time, Usually, it carries out in 30 second-24 hours.
상기 건조 공정 이후에는, 냉각 과정을 더 포함할 수 있고, 상기 냉각 과정은 바인더의 재결정 조직이 잘 형성되도록 실온까지 서냉(Slow cooling)하는 것일 수 있다.After the drying process, a cooling process may be further included, and the cooling process may be slow cooling to room temperature so that the recrystallized structure of the binder is well formed.
또한, 필요한 경우 건조 공정 이후 전극의 용량 밀도를 높이고 집전체와 활물질들 간의 접착성을 증가시키기 위해서, 고온 가열된 2개의 롤 사이로 전극을 통과시켜 원하는 두께로 압축하는 압연(Pressing) 공정을 수행할 수 있다. 상기 압연 공정은 본 발명에서 특별히 한정하지 않으며, 공지의 압연 공정이 가능하다. 일례로, 회전 롤 사이에 통과시키거나 평판 프레스기를 이용하여 수행한다.In addition, if necessary, in order to increase the capacity density of the electrode after the drying process and to increase the adhesion between the current collector and the active materials, a pressing process may be performed in which the electrode is passed between two hot-heated rolls and compressed to a desired thickness. Can be. The said rolling process is not specifically limited in this invention, A well-known rolling process is possible. In one example, it is passed between the rotating rolls or performed using a flat plate press.
이하에서는 본 발명의 바람직한 실시예 및 첨부하는 도면을 참조하여 본 발명을 상세히 설명한다. 하지만, 본 발명은 하기 실시예에 의해 한정되는 것은 아니며, 본 발명의 기술 사상 범위 내에서 여러 가지 변형 또는 수정할 수 있음은 이 분야의 통상의 기술을 가진자에게는 명백한 것이다.Hereinafter, with reference to the preferred embodiments of the present invention and the accompanying drawings will be described in detail the present invention. However, the present invention is not limited by the following examples, and it can be apparent to those skilled in the art that various modifications or changes can be made within the scope of the present invention.
이하에서 'PEOn-리튬염'으로 표기한 것에서, n은 리튬염의 Li 1몰에 대응하는 PEO의 몰수를 나타내고, 상기 'PEOn-리튬염-X'로 표기한 것에서 X는 semi-IPN 구조로 가교된 것을 의미한다.Hereinafter, in what is referred to as 'PEO n -lithium salt', n represents the number of moles of PEO corresponding to 1 mol of Li of the lithium salt, and X is a semi-IPN structure in what is referred to as 'PEO n -lithium salt-X' It means crosslinked with.
고분자 전해질막 제조Polymer electrolyte membrane manufacturing
<제조예 1><Manufacture example 1>
1. 아세토니트릴(Acetonitrile: AN)에 PEO(Mw ≒ 4,000,000)와 LiFSI를 EO : Li = 5 : 1 의 몰비가 되도록 혼합하였다.1. PEO (Mw ≒ 4,000,000) and LiFSI were mixed with acetonitrile (AN) in a molar ratio of EO: Li = 5: 1.
2. 상기 용액을 이용하여 솔루션 캐스팅(Solution Casting) 방법으로 3 ㎛의 고분자 전해질 막, PEO5-LiFSI막을 제조하였다.2. Using the solution, a 3 μm polymer electrolyte membrane and a PEO 5 -LiFSI membrane were prepared by a solution casting method.
<제조예 2><Manufacture example 2>
1. 아세토니트릴(Acetonitrile: AN)에 PEO(Mw ≒ 4,000,000)와 LiFSI를 EO : Li = 20 : 1의 몰비가 되도록 혼합하였다.1. Acetonitrile (AN) was mixed with PEO (Mw ≒ 4,000,000) and LiFSI in a molar ratio of EO: Li = 20: 1.
2. 상기 용액을 이용하여 솔루션 캐스팅(Solution Casting) 방법으로 20 ㎛의 고분자 전해질 막, PEO20-LiFSI막을 제조하였다.2. Using the solution, a 20 μm polymer electrolyte membrane and a PEO 20 -LiFSI membrane were prepared by a solution casting method.
<제조예 3><Manufacture example 3>
1. 아세토니트릴(Acetonitrile: AN)에 PEO(Mw ≒ 4,000,000)와 LiFSI를 EO : Li = 20 : 1 의 몰비가 이 되도록 혼합하였다.1. Acetonitrile (AN) was mixed with PEO (Mw ≒ 4,000,000) and LiFSI in a molar ratio of EO: Li = 20: 1.
2. 상기 용액에 PEGDA(n = 10)와 개시제 BPO(Benzoyl peroxide)를 PEO20-LiTFSI의 10 wt%가 되도록 혼합한 후 균질한 용액이 될 때까지 교반(Stirring)하였다. 이때, BPO는 PEGDA의 1 wt%가 되도록 혼합했다.2. The solution was mixed with PEGDA (n = 10) and initiator BPO (Benzoyl peroxide) to 10 wt% of PEO 20 -LiTFSI and stirred until a homogeneous solution. At this time, BPO was mixed so as to be 1 wt% of PEGDA.
3. 상기 혼합액을 이용하여 솔루션 캐스팅(Solution Casting) 방법으로 20 ㎛의 고분자 전해질막, PEO20-LiFSI-X막을 제조하였다.3. A 20 μm polymer electrolyte membrane and a PEO 20 -LiFSI-X membrane were prepared by a solution casting method using the mixed solution.
<제조예 4><Manufacture example 4>
1. 아세토니트릴(Acetonitrile: AN)에 PEO(Mw ≒ 4,000,000)와 LiFSI를 EO : Li = 2 : 1 의 몰비가 되도록 혼합하였다.1. Acetonitrile (AN) was mixed with PEO (Mw ≒ 4,000,000) and LiFSI in a molar ratio of EO: Li = 2: 1.
2. 상기 용액을 이용하여 솔루션 캐스팅(Solution Casting) 방법으로 3 ㎛의 고분자 전해질 막, PEO2-LiFSI막을 제조하였다.2. Using the solution, a 3 μm polymer electrolyte membrane and a PEO 2 -LiFSI membrane were prepared by a solution casting method.
<제조예 5>Production Example 5
1. 아세토니트릴(Acetonitrile: AN)에 PEO(Mw ≒ 4,000,000)와 LiFSI를 EO : Li = 12 : 1 의 몰비가 되도록 혼합하였다.1. Acetonitrile (AN) was mixed with PEO (Mw ≒ 4,000,000) and LiFSI in a molar ratio of EO: Li = 12: 1.
2. 상기 용액을 이용하여 솔루션 캐스팅(Solution Casting) 방법으로 10 ㎛의 고분자 전해질 막, PEO12-LiFSI막을 제조하였다.2. Using the solution, a 10 μm polymer electrolyte membrane and a PEO 12 -LiFSI membrane were prepared by a solution casting method.
이온 전도도 측정Ionic Conductivity Measurement
상기 제조예 1 및 제조예 2의 전해질막을 각각 전극(스테인레스, SUS) 사이에 놓고 임피던스 분석기(Zahner, IM6)를 이용하여 두 개의 차단 전극을 두고 교류를 가하여 얻어진 응답으로부터 60 ℃에서의 이온 전도도를 측정한 결과를 하기 표 1에 나타내었다.The electrolyte membranes of Preparation Example 1 and Preparation Example 2 were placed between electrodes (stainless steel and SUS), respectively, and two ion blocking electrodes were applied using an impedance analyzer (Zahner, IM6). The measurement results are shown in Table 1 below.
종류Kinds 이온전도도(60℃)Ion Conductivity (60 ℃)
제조예 1Preparation Example 1 PEO5-LiFSIPEO 5 -LiFSI 1.3×10-4S/cm1.3 × 10 -4 S / cm
제조예 2Preparation Example 2 PEO20-LiFSIPEO 20 -LiFSI 3.0×10-4S/cm3.0 × 10 -4 S / cm
표 1에 나타난 바와 같이, 60 ℃에서 제조예 1의 PEO5-LiFSI막의 이온 전도도인 1.3×10-4S/cm가 제조예 2의 PEO20-LiFSI막의 이온 전도도는 3.0×10-4S/cm보다 매우 낮은 것으로 확인되었다. 따라서 Li의 함량이 높아질수록 이온 전도도가 낮은 것을 확인하였으며, 제조예 1의 PEO5-LiFSI막을 단일막으로 사용하기에는 문제가 있음을 예측할 수 있다.As shown in Table 1, at 60 ℃ Production Example 1 of PEO 5 -LiFSI membrane ion conductivity of 1.3 × 10 -4 S / cm Production Example 2 of the 20 PEO -LiFSI membrane ionic conductivity was 3.0 × 10 -4 S / It was found to be much lower than cm. Therefore, it was confirmed that the higher the Li content, the lower the ion conductivity, and it can be predicted that there is a problem in using the PEO 5 -LiFSI membrane of Preparation Example 1 as a single membrane.
리튬 시메트릭 전지 제조Lithium Simmetric Battery Manufacturing
<실시예 1><Example 1>
도 2에 도시된 바와 같이, 리튬 금속 표면에 상기 제조예 1의 PEO5-LiFSI막을 적용하고 그 사이에 상기 제조예 3의 PEO20-LiFSI-X막을 적용하여 리튬 시메트릭 전지(Li symmetric cell)를 제작하였다.As shown in FIG. 2, a lithium symmetric cell is applied by applying the PEO 5 -LiFSI film of Preparation Example 1 to the surface of a lithium metal and applying the PEO 20 -LiFSI-X film of Preparation Example 3 therebetween. Was produced.
<비교예 1>Comparative Example 1
도 1에 도시된 바와 같이, 리튬 사이에 상기 제조예 3의 PEO20-LiFSI-X막을 적용한 리튬 시메트릭 전지(Li symmetric cell)를 제작하였다.As shown in FIG. 1, a lithium symmetric cell was fabricated by applying the PEO 20 —LiFSI-X film of Preparation Example 3 between lithium.
전고체 전지 제조All Solid Battery Manufacturing
<실시예 2><Example 2>
1. LFP(LiFePO4)활물질과 도전재, 고분자 전해질을 혼합하여 공극률(Porosity) 10 % 이하, 로딩(Loading) 2 mAh/cm2의 양극을 10.6 cm2의 크기로 제조하였다.1. A positive electrode having a porosity of 10% or less and a loading of 2 mAh / cm 2 was prepared by mixing LFP (LiFePO 4 ) active material, a conductive material, and a polymer electrolyte to a size of 10.6 cm 2 .
2. 리튬 위에 상기 제조예 1의 PEO5-LiFSI인 제1 고분자 전해질을 위치시켰다. 2. The first polymer electrolyte of PEO 5 -LiFSI of Preparation Example 1 was placed on lithium.
3. 상기 제1 고분자 전해질 위에 상기 제조예 3의 PEO20-LiFSI-X인 제2 고분자 전해질을 올렸다.3. The second polymer electrolyte PEO 20 -LiFSI-X of Preparation Example 3 was mounted on the first polymer electrolyte.
4. 상기 제2 고분자 전해질 위에 상기 1 단계에서 제조한 양극을 포개어 도 3(b)에 도시된 바와 같은 전고체 전지를 제작하였다.4. The positive electrode prepared in step 1 was stacked on the second polymer electrolyte to prepare an all-solid-state battery as shown in FIG. 3 (b).
<실시예 3><Example 3>
1. LFP(LiFePO4)활물질과 도전재, 고분자 전해질을 혼합하여 공극률(Porosity) 10 % 이하, 로딩(Loading) 2 mAh/cm2의 양극을 10.6 cm2의 크기로 제조하였다.1. A positive electrode having a porosity of 10% or less and a loading of 2 mAh / cm 2 was prepared by mixing LFP (LiFePO 4 ) active material, a conductive material, and a polymer electrolyte to a size of 10.6 cm 2 .
2. 리튬 위에 상기 제조예 4의 PEO2-LiFSI인 제1 고분자 전해질을 위치시켰다. 2. The first polymer electrolyte of PEO 2 -LiFSI of Preparation Example 4 was placed on lithium.
3. 상기 제1 고분자 전해질 위에 상기 제조예 2의 PEO20-LiFSI인 제2 고분자 전해질을 올렸다.3. The second polymer electrolyte of PEO 20 -LiFSI of Preparation Example 2 was mounted on the first polymer electrolyte.
4. 상기 제2 고분자 전해질 위에 상기 1 단계에서 제조한 양극을 포개어 전고체 전지를 제작하였다.4. An all-solid-state battery was manufactured by stacking the positive electrode prepared in step 1 on the second polymer electrolyte.
<비교예 2>Comparative Example 2
1. LFP(LiFePO4)활물질과 도전재, 고분자 전해질을 혼합하여 공극률(Porosity) 10 % 이하, 로딩(Loading) 2 mAh/cm2의 양극을 10.6 cm2의 크기로 제조하였다.1. A positive electrode having a porosity of 10% or less and a loading of 2 mAh / cm 2 was prepared by mixing LFP (LiFePO 4 ) active material, a conductive material, and a polymer electrolyte to a size of 10.6 cm 2 .
2. 리튬 위에 상기 제조예 3의 PEO20-LiFSI-X막을 위치시켰다.2. The PEO 20 -LiFSI-X film of Preparation Example 3 was placed on lithium.
3. 상기 1 단계에서 제조한 양극을 포개어 도 3(a)에 도시된 바와 같은 전고체 전지를 제작하였다.3. The positive electrode prepared in step 1 was stacked to produce an all-solid-state battery as shown in FIG.
<비교예 3>Comparative Example 3
1. LFP(LiFePO4)활물질과 도전재, 고분자 전해질을 혼합하여 공극률(Porosity) 10 % 이하, 로딩(Loading) 2 mAh/cm2의 양극을 10.6 cm2의 크기로 제조하였다.1. A positive electrode having a porosity of 10% or less and a loading of 2 mAh / cm 2 was prepared by mixing LFP (LiFePO 4 ) active material, a conductive material, and a polymer electrolyte to a size of 10.6 cm 2 .
2. 리튬 위에 상기 제조예 2의 PEO20-LiFSI 제2 고분자 전해질을 위치시켰다. 2. The PEO 20 -LiFSI second polymer electrolyte of Preparation Example 2 was placed on lithium.
3. 상기 제2 고분자 전해질 위에 상기 제조예 1의 PEO5-LiFSI인 제1 고분자 전해질을 올렸다.3. The first polymer electrolyte of PEO 5 -LiFSI of Preparation Example 1 was mounted on the second polymer electrolyte.
4. 상기 제1 고분자 전해질 위에 상기 1 단계에서 제조한 양극을 포개어 전고체 전지를 제작하였다.4. An all-solid-state battery was manufactured by stacking the positive electrode prepared in step 1 on the first polymer electrolyte.
<비교예 4><Comparative Example 4>
1. LFP(LiFePO4)활물질과 도전재, 고분자 전해질을 혼합하여 공극률(Porosity) 10 % 이하, 로딩(Loading) 2 mAh/cm2의 양극을 10.6 cm2의 크기로 제조하였다.1. A positive electrode having a porosity of 10% or less and a loading of 2 mAh / cm 2 was prepared by mixing LFP (LiFePO 4 ) active material, a conductive material, and a polymer electrolyte to a size of 10.6 cm 2 .
2. 리튬 위에 상기 제조예 5의 PEO12-LiFSI 제2 고분자 전해질을 위치시켰다. 2. The PEO 12 -LiFSI second polymer electrolyte of Preparation Example 5 was placed on lithium.
3. 상기 제2 고분자 전해질 위에 상기 제조예 2의 PEO20-LiFSI인 제2 고분자 전해질을 올렸다.3. A second polymer electrolyte of PEO 20 -LiFSI of Preparation Example 2 was mounted on the second polymer electrolyte.
4. 상기 제2 고분자 전해질 위에 상기 1 단계에서 제조한 양극을 포개어 전고체 전지를 제작하였다.4. An all-solid-state battery was manufactured by stacking the positive electrode prepared in step 1 on the second polymer electrolyte.
계면저항 측정Interface resistance measurement
상기 실시예 1과 비교예 1의 리튬 시메트릭 전지(Li symmetric cell) 및 상기 실시예 3과 비교예 3, 4의 전고체 전지를 전기화학적 임피던스 분광법(EIS: Electrochemical impedance spectroscopy) 측정을 통해 저항을 측정하였으며, 이렇게 얻어진 도 1 및 도 2의 그래프에서 반원 형상의 선이 x축과 만나는 지점으로 계면저항을 확인하였다. 계면저항을 하기 표 2에 나타내었다.The lithium symmetric cell of Example 1 and Comparative Example 1 and the all-solid-state cells of Example 3 and Comparative Examples 3 and 4 were measured by electrochemical impedance spectroscopy (EIS) measurement. In the graphs of FIGS. 1 and 2 thus obtained, the interface resistance was confirmed at the point where the semi-circular line meets the x-axis. Interfacial resistance is shown in Table 2 below.
구분division 시메트릭 전지Symmetric battery 전고체 전지All-solid-state battery
실시예 1Example 1 비교예 1Comparative Example 1 실시예 3Example 3 비교예 3Comparative Example 3 비교예 4Comparative Example 4
계면저항(Ω)Interface resistance (Ω) 130130 350350 200200 350350 22002200
도 1에 도시된 비교예 1인 PEO20-LiFSI-X만이 적용된 전지의 저항은 350 Ω 임에 비해, 도 2에 도시된 실시예 1인 PEO5-LiFSI가 PEO20-LiFSI-X사이에 중간층(Interlayer)으로 적용된 전지는 두께가 6 ㎛ 증가함에도 불구하고 130 Ω 정도로 저항이 매우 감소하는 것을 확인하였다. 이로 인해 PEO5-LiFSI막은 리튬과의 계면저항이 매우 낮다는 것을 알 수 있다.The resistance of the cell to which only PEO 20 -LiFSI-X, which is Comparative Example 1 shown in FIG. 1, is 350 Ω, while the intermediate layer between PEO 20 -LiFSI-X, which is PEO 5 -LiFSI, which is Example 1 shown in FIG. The battery applied as an interlayer was found to have a very low resistance of about 130 Ω despite the increase in thickness of 6 μm. Therefore, it can be seen that the PEO 5 -LiFSI film has a very low interfacial resistance with lithium.
또한 실시예 3인 리튬 음극 기준 PEO2-LiFSI 및 PEO20-LiFSI가 순차적으로 적용된 전고체 전지의 저항은 200 Ω으로 나타났으며, 제1 고분자와 제2 고분자의 위치를 바꾼 비교예 3인 리튬 음극 기준 PEO20-LiFSI 및 PEO5-LiFSI가 순차적으로 적용된 전고체 전지의 저항은 350 Ω으로 나타났으며, 제2 고분자만을 적용한 비교예 4인 리튬 음극 기준 PEO12-LiFSI 및 PEO20-LiFSI가 순차적으로 적용된 전고체 전지의 저항은 2200 Ω으로 나타났다. 이로 인해 리튬 음극 기준 제1 고분자 전해질층이 리튬에 대면하여 배치되고 그 위에 제2 고분자 전해질층이 배치된 전지의 계면저항이 더 낮음을 알 수 있으며, 제2 고분자 전해질층만 사용한 전지보다 제1 고분자 전해질층과 제2 고분자 전해질층을 동시에 사용한 전지의 계면저항이 더 낮음을 알 수 있다.In addition, the resistance of the all-solid-state battery in which PEO 2 -LiFSI and PEO 20 -LiFSI based on the lithium negative electrode of Example 3 were sequentially applied was 200 Ω, and Comparative Example 3, which changed the positions of the first polymer and the second polymer, was used. a negative electrode based on PEO and PEO 5 20 -LiFSI -LiFSI was the resistance of the all-solid battery are applied sequentially appeared as 350 Ω, the second polymer only comparative example 4 of the negative electrode based on lithium PEO 12 20 PEO -LiFSI and applying the -LiFSI The resistance of the all-solid-state battery sequentially applied was 2200 Ω. As a result, it can be seen that the interfacial resistance of the battery in which the lithium negative electrode reference first polymer electrolyte layer is disposed facing lithium and the second polymer electrolyte layer is disposed thereon is lower, and that the first polymer electrolyte layer is the first polymer electrolyte layer than the battery using only the second polymer electrolyte layer. It can be seen that the interface resistance of the battery using the polymer electrolyte layer and the second polymer electrolyte layer at the same time is lower.
방전용량 측정Discharge capacity measurement
도 4에 도시된 바와 같이, PEO20-LiFSI-X만을 적용한 전고체 전지(비교예 2, (a))는 양극의 로딩이 높고 리튬과의 계면저항 역시 높아 방전 용량이 130 mAh/g으로 충분히 발현되지 않았다.As shown in FIG. 4, an all-solid-state battery (Comparative Example 2, (a)) using only PEO 20 -LiFSI-X has a high positive electrode loading and a high interfacial resistance with lithium, so that the discharge capacity is 130 mAh / g. It was not expressed.
그러나 본 발명의 제1 고분자 전해질인 PEO5-LiFSI 고분자 전해질 막을 리튬 음극과 제2 고분자 전해질인 PEO20-LiFSI-X사이(Interlayer)에 적용한 전고체 전지(실시예 2, (b))는 리튬과의 계면저항이 크게 감소하여 방전 과전압이 줄어들며, 155 mAh/g의 충분한 방전 용량이 구현되는 것을 확인하였다. 따라서, 제1 고분자 전해질인 PEO5-LiFSI 고분자 전해질 막을 전지에 적용하면 출력 특성 및 에너지 밀도를 개선시킬 수 있다.However, an all-solid-state battery (Examples 2 and (b)) in which the PEO 5 -LiFSI polymer electrolyte membrane of the present invention is applied between the lithium anode and the second polymer electrolyte PEO 20 -LiFSI-X (Interlayer) is lithium. It was confirmed that the interfacial resistance with and the discharge overvoltage is reduced significantly, and sufficient discharge capacity of 155 mAh / g is implemented. Therefore, when the PEO 5 -LiFSI polymer electrolyte membrane, which is the first polymer electrolyte, is applied to a battery, output characteristics and energy density can be improved.

Claims (11)

  1. 폴리에틸렌옥사이드계 고분자 및 리튬염의 EO : Li의 몰비가 1 : 1 ~ 7 : 1인 제1 고분자 전해질층; 및A first polymer electrolyte layer having a molar ratio of EO: Li of the polyethylene oxide polymer and the lithium salt of from 1: 1 to 7: 1; And
    폴리에틸렌옥사이드계 고분자 및 리튬염의 EO : Li의 몰비가 30 : 1 ~ 8 : 1 인 제2 고분자 전해질층;A second polymer electrolyte layer having a molar ratio of EO: Li of the polyethylene oxide polymer and the lithium salt of 30: 1 to 8: 1;
    을 포함하는 다층 구조의 전고체 전지용 고분자 전해질.Polymer electrolyte for a solid-state battery of a multi-layer structure comprising a.
  2. 제1항에 있어서,The method of claim 1,
    상기 제1 고분자 전해질층의 두께는 1 ~ 5 ㎛인 것을 특징으로 하는 다층 구조의 전고체 전지용 고분자 전해질.The thickness of the first polymer electrolyte layer is a polymer electrolyte for a solid-state battery of a multi-layer structure, characterized in that 1 to 5 ㎛.
  3. 제1항에 있어서,The method of claim 1,
    상기 제2 고분자 전해질층의 두께는 5 ~ 50 ㎛인 것을 특징으로 하는 다층 구조의 전고체 전지용 고분자 전해질.The thickness of the second polymer electrolyte layer is a polymer electrolyte for a solid-state battery of a multilayer structure, characterized in that 5 to 50 ㎛.
  4. 제1항에 있어서,The method of claim 1,
    상기 폴리에틸렌옥사이드계 고분자의 중량평균분자량이 1,000,000 내지 8,000,000인 것을 특징으로 하는 다층 구조의 전고체 전지용 고분자 전해질.Polymer electrolyte for a multi-layer battery, characterized in that the weight average molecular weight of the polyethylene oxide polymer is 1,000,000 to 8,000,000.
  5. 제1항에 있어서,The method of claim 1,
    상기 리튬염은 LiCl, LiBr, LiI, LiClO4, LiBF4, LiB10Cl10, LiPF6, LiCF3SO3, LiCF3CO2, LiAsF6, LiSbF6, LiAlCl4, CH3SO3Li, CF3SO3Li, LiSCN, LiC(CF3SO2)3, (CF3SO2)2NLi, (FSO2)2NLi, 클로로 보란 리튬, 저급 지방족 카르본산 리튬, 4-페닐 붕산 리튬, 이미드 및 이들의 조합으로부터 선택된 1종을 포함하는 것을 특징으로 하는 다층 구조의 전고체 전지용 고분자 전해질.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 , LiAsF 6 , LiSbF 6 , LiAlCl 4 , CH 3 SO 3 Li, CF 3 SO 3 Li, LiSCN, LiC (CF 3 SO 2 ) 3 , (CF 3 SO 2 ) 2 NLi, (FSO 2 ) 2 NLi, chloroborane lithium, lower aliphatic carbonate, lithium 4-phenylborate, imide And a polymer selected from a combination thereof. The polymer electrolyte for an all-solid-state battery having a multilayer structure.
  6. 제1항에 있어서,The method of claim 1,
    상기 제2 고분자 전해질층은 가교성 단량체에 의해 가교되어 반 상호침투 고분자 네트워크를 형성하는 것을 특징으로 하는 다층 구조의 전고체 전지용 고분자 전해질.The second polymer electrolyte layer is cross-linked by a crosslinkable monomer to form a semi-interpenetrating polymer network polymer electrolyte for a multi-layer battery, characterized in that.
  7. 제6항에 있어서,The method of claim 6,
    상기 가교성 단량체는 ―(CH2―CH2―O)― 반복 단위를 포함하는 것을 특징으로 하는 다층 구조의 전고체 전지용 고분자 전해질.The crosslinkable monomer comprises a-(CH 2 -CH 2 -O)-repeating unit, the polymer electrolyte for a solid-state battery of a multi-layer structure, characterized in that.
  8. 제7항에 있어서,The method of claim 7, wherein
    상기 가교성 단량체는 말단에 2개 내지 8개의 알킬렌성 불포화 결합을 포함하는 것을 특징으로 하는 다층 구조의 전고체 전지용 고분자 전해질.The crosslinkable monomer is a polymer electrolyte for a solid-state battery of a multi-layer structure, characterized in that it comprises from 2 to 8 alkylene unsaturated unsaturated bonds.
  9. 제6항에 있어서,The method of claim 6,
    상기 가교성 단량체는 상기 폴리에틸렌옥사이드계 고분자 및 리튬염에 대하여 5 ~ 50 wt%로 포함되는 것을 특징으로 하는 다층 구조의 전고체 전지용 고분자 전해질.The crosslinkable monomer is a polymer electrolyte for a multi-layer battery, characterized in that contained in 5 to 50 wt% with respect to the polyethylene oxide-based polymer and lithium salt.
  10. 양극, 음극 및 이들 사이에 개재되는 고체 고분자 전해질을 포함하여 구성되는 전고체 전지에 있어서, In the all-solid-state battery comprising a positive electrode, a negative electrode and a solid polymer electrolyte interposed therebetween,
    상기 고체 고분자 전해질은 제1항 내지 제9항 중 어느 한 항의 고분자 전해질인 것을 특징으로 하는 전고체 전지.The solid polymer electrolyte is an all-solid-state battery, characterized in that the polymer electrolyte of any one of claims 1 to 9.
  11. 제10항에 있어서,The method of claim 10,
    상기 제1 고분자 전해질층은 상기 음극에 대면하여 배치되는 것을 특징으로 하는 전고체 전지.And the first polymer electrolyte layer is disposed to face the negative electrode.
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