WO2018056615A1 - Électrode négative comprenant de multiples couches de protection et batterie secondaire au lithium la comprenant - Google Patents

Électrode négative comprenant de multiples couches de protection et batterie secondaire au lithium la comprenant Download PDF

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WO2018056615A1
WO2018056615A1 PCT/KR2017/009807 KR2017009807W WO2018056615A1 WO 2018056615 A1 WO2018056615 A1 WO 2018056615A1 KR 2017009807 W KR2017009807 W KR 2017009807W WO 2018056615 A1 WO2018056615 A1 WO 2018056615A1
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Prior art keywords
protective layer
lithium
secondary battery
negative electrode
lithium secondary
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PCT/KR2017/009807
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English (en)
Korean (ko)
Inventor
손병국
장민철
최정훈
성다영
박세호
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주식회사 엘지화학
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Priority claimed from KR1020170092180A external-priority patent/KR102003307B1/ko
Application filed by 주식회사 엘지화학 filed Critical 주식회사 엘지화학
Priority to CN201780030524.7A priority Critical patent/CN109155396B/zh
Priority to EP17853329.5A priority patent/EP3428998B1/fr
Priority to JP2018549464A priority patent/JP6656718B2/ja
Priority to US16/089,978 priority patent/US10957911B2/en
Publication of WO2018056615A1 publication Critical patent/WO2018056615A1/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
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • 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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/134—Electrodes based on metals, Si or alloys
    • 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 negative electrode including a multiple protective layer and a lithium secondary battery including the same, and more particularly, to effectively inhibit the growth of dendrite (Dendrite) and has a high ion conductivity, negative electrode comprising a multi protective layer And it relates to a lithium secondary battery comprising the same.
  • the electrochemical device is the field that is receiving the most attention in this respect, and the development of secondary batteries that can be charged and discharged among them is the focus of attention, and in recent years to improve the capacity density and energy efficiency in the development of such R & D on the design of new electrodes and batteries is ongoing.
  • lithium secondary batteries developed in the early 1990s have a higher operating voltage and a higher energy density than conventional batteries such as Ni-MH, Ni-Cd, and sulfuric acid-lead batteries that use an aqueous electrolyte solution. I am in the spotlight.
  • the lithium secondary battery has a structure in which an electrode assembly including a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode is stacked or wound, and the electrode assembly is embedded in a battery case and a nonaqueous electrolyte is injected into the lithium secondary battery. do.
  • the lithium secondary battery produces electrical energy by oxidation and reduction reactions when lithium ions are inserted / desorbed from the positive electrode and the negative electrode.
  • lithium metal, carbon, and the like are used as active materials for the negative electrode of a lithium secondary battery
  • lithium oxide, transition metal oxide, metal chalcogen compound, and conductive polymer are used as the active materials for the positive electrode.
  • lithium secondary batteries using lithium metal as a negative electrode attach lithium foil on a copper current collector or use lithium metal sheet itself as an electrode.
  • Lithium metal has attracted great attention as a high capacity cathode material due to its low potential and large capacity.
  • lithium metal When lithium metal is used as a negative electrode, electron density nonuniformity may occur on the surface of lithium metal due to various factors when the battery is driven.
  • the lithium dendrite in the form of twigs is formed on the surface of the electrode, so that protrusions are formed or grown on the surface of the electrode, thereby making the electrode surface very rough.
  • These lithium dendrites along with deterioration of the cell, cause severe damage to the separator and short circuit of the cell. As a result, there is a risk of explosion and fire of the battery due to an increase in the battery temperature.
  • Patent Document 1 Republic of Korea Patent Publication No. 10-1621410 "Lithium electrode and lithium secondary battery comprising the same"
  • Patent Document 2 Korean Unexamined Patent Publication No. 10-2016-0052351 "A lithium metal electrode having a stable protective layer and a lithium secondary battery comprising the same"
  • lithium dendrites of the lithium secondary battery are precipitated on the surface of the negative electrode, thereby causing volume expansion of the cell. Accordingly, the present inventors have conducted various studies, and have found a way to solve the problem caused by the dendrite through the structural modification of the electrode and completed the present invention.
  • an object of the present invention is to solve the problem of the volume expansion of the cell due to lithium dendrites through the deformation of the electrode structure, and to provide a lithium secondary battery with improved battery performance.
  • the present invention is a lithium metal layer
  • a first protective layer formed on the lithium metal layer and maintaining an interface with the lithium metal layer
  • a second protective layer formed on the first protective layer and physically inhibiting growth of dendrites
  • a negative electrode for a lithium secondary battery comprising a; a third protective layer formed on the second protective layer and supporting the structure of the second protective layer.
  • the first protective layer may have an ion conductivity of 10 ⁇ 7 S / Cm or more, and an electrolyte absorbance of 150 wt% or more.
  • the first protective layer may include one or more selected from the group consisting of polyvinyllidene fluoride-co-hexafluoropropylene (PVdF-HFP) polymer, polyurethane-based polymer, and polyacrylic-based polymer.
  • PVdF-HFP polyvinyllidene fluoride-co-hexafluoropropylene
  • the second protective layer may have a Young's modulus of 5 GPa or more, a Li ion conductivity of 10 ⁇ 7 S / Cm or more, and an electrolyte absorption of 150 wt% or less.
  • the second protective layer is LiPON (Lithium Phosphorus Oxynitride), LiBON (Lithium Boron Oxynitride), zirconium oxide, ⁇ -alumina, LISICON (Lithium Super Ionic Conductor) compound, Li 2 SP 2 S 5 type compound, Li 3 N, LiI, Li 5 NI 2 , Li 3 N-LiI-LiOH, LiSiO 4 , LiSiO 4 -LiI-LiOH, Li 2 SiS 3 , Li 4 SiO 4 , Li 4 SiO 4 -LiI-LiOH, Li 2 S, Li 2 S-SiS 2 , Li 2 S-GeS 2 , Li 2 SB 2 S 5 , Li 2 S-Al 2 S 2 , Li 2 O-Al 2 O 3 -TiO 2 -P 2 O 5 (LATP), It may include at least one selected from the group consisting of CaF 2 , AgI, RbAg 4 I 5
  • the third protective layer may have an ionic conductivity of 10 ⁇ 5 S / Cm or more and an electrolyte absorbency of 150 wt% or less.
  • the third protective layer may include one or more selected from the group consisting of PVdF-HFP polymer, polyurethane-based polymer and polyacrylic-based polymer.
  • the present invention is a lithium metal layer
  • a negative electrode for a lithium secondary battery comprising a; three or more layers independently selected from the group consisting of a dendrite growth inhibitory layer, a single ion conductive layer and a polymer layer.
  • the dendrite growth inhibiting layer may include at least one selected from the group consisting of PVdF-HFP polymer, LiPON, LiBON, polyurethane-based polymer, polypropylene-based polymer and polycarbonate-based polymer.
  • the present invention provides a lithium secondary battery including the negative electrode.
  • the multiple protective layer according to the present invention can physically inhibit the growth of lithium dendrites on the electrode surface and at the same time can effectively transfer lithium ions to the lithium metal electrode and has excellent ion conductivity so that the protective layer itself does not act as a resistive layer. Since the overvoltage is not applied at the time of discharging, it is possible to prevent performance degradation of the battery and to ensure stability when driving the battery.
  • the lithium electrode including the multiple protective layer of the present invention is preferably applicable as a negative electrode of a lithium secondary battery, which is a large-capacity energy storage device from most small electronic devices using various devices, for example, lithium metal as a negative electrode. Applicable to the back.
  • FIG. 1 is a schematic view of an electrode for a lithium secondary battery according to an embodiment of the present invention.
  • the present invention is a lithium metal layer 110;
  • a second protective layer 130 formed on the first protective layer 120 and physically inhibiting growth of dendrites
  • FIG. 1 is a view showing a negative electrode 100 for a lithium secondary battery according to an embodiment of the present invention.
  • the first protective layer 120, the second protective layer 130, and the third protective layer 140 are sequentially disposed on the lithium metal layer 110. Formed. Although the first protective layer 120, the second protective layer 130, and the third protective layer 140 are formed only on one surface of the lithium metal layer 110 in FIG. 2, both surfaces of the lithium metal layer 110 may be formed.
  • lithium metal when used as a battery negative electrode, the following problems exist.
  • a passivation layer is formed by reacting with electrolyte, water, impurities in a battery, lithium salt, and the like, and this layer causes a local current density difference to form dendritic lithium dendrite.
  • the dendrite thus formed may grow and cause an internal short circuit directly between the anode and the pores of the separator, thereby causing the battery to explode.
  • the growth of the dendrite may be prevented by forming the first protective layer 120, the second protective layer 130, and the third protective layer 140 on the lithium metal layer 110.
  • the lithium metal layer 110 may use a plate-shaped metal.
  • the lithium metal layer 110 may be adjusted in width depending on the shape of the electrode to facilitate electrode manufacturing.
  • the thickness of the lithium metal layer may be 1 to 50 ⁇ m.
  • the first protective layer 120, the second protective layer 130, and the third protective layer 140 are stacked on the lithium metal layer 110, smooth movement of lithium ions between the lithium metal layer 110 and the electrolyte is performed.
  • ionic conductivity for lithium ions may be basically required. Therefore, it is preferable that all three protective layers have a Li ion conductivity of at least 10 ⁇ 7 S / Cm or more.
  • first protective layer 120, the second protective layer 130, and the third protective layer 140 have respective roles to be described later in the triple stacked structure, and when the triple stacked structure is as described above, dendrites The effect of inhibiting the growth of and the effect of maintaining the ionic conductivity may be best.
  • the protective layer may require an electrolyte absorbance (uptake) of a predetermined range or more or less, the first protective layer may have an electrolyte absorbance of 150% or more, and the second protective layer and the third protective layer may be 150 It may have an electrolyte absorbency of less than or equal to%.
  • electrolyte absorbency means how much the said protective layer can absorb electrolyte solution, and shows how much the mass after absorption increases compared with the mass before electrolyte absorption of a protective layer.
  • the first protective layer may have an electrolyte absorbency of 150% or more to increase ion conductivity, and may physically be flexible to wrap growing lithium, thereby maintaining an interface between the lithium metal layer and the second protective layer.
  • the second protective layer and the third protective layer has an electrolyte absorbency of 150% or less, have relatively hard physical properties, and can effectively suppress dendrite formation.
  • the first protective layer 120 is formed on the lithium metal layer 110, and maintains an interface between the lithium metal layer 110 and the protective layer while the lithium ion battery is charged and discharged. It plays a role.
  • the first protective layer 120 has a Li ion conductivity of 10 -7 S / Cm or more, the electrolyte absorbance may be 150% by weight or more, preferably 150 ⁇ 250% by weight, PVdF-HFP polymer, poly It may include one or more selected from the group consisting of a urethane-based polymer and a polyacrylic polymer.
  • the first protective layer 120 may be physically relatively flexible due to high electrolyte absorption and may be suitable for maintaining an interface.
  • the content of HFP in the PVdF-HFP may be 15% by weight or more, the shore hardness of the polyurethane-based polymer may be 80 A or less, and the crosslinking density of the polyacrylic polymer may be 10 ⁇ 4 mol / g or less. If the Shore hardness is too low, the volume of the battery may increase because the amount of the electrolyte impregnation is too high. If the crosslinking density is too high, the ion conductivity may decrease and the resistance may increase.
  • the interface between the lithium metal layer 110 and the protective layer is not maintained in the lithium ion battery, which may cause a decrease in battery capacity due to an increase in resistance.
  • the thickness of the first protective layer 120 is sufficient to apply only enough to maintain the interface, and if too thick, the thickness of the first protective layer 120 is 1 to 10 because it causes an increase in unnecessary thickness of the electrode. May be ⁇ m.
  • the second protective layer 130 is formed on the first protective layer 120, and serves to physically inhibit the growth of the dendrite.
  • the second protective layer 130 preferably has strong physical strength and ion conductivity.
  • the second protective layer 130 has a Young's modulus of 5 GPa or more, a Li ion conductivity of 10 ⁇ 7 S / Cm or more, and an electrolyte absorbency of 150 wt% or less, preferably 30 to 150 wt% Can be.
  • the second protective layer 130 is LiPON, LiBON, zirconium oxide, ⁇ -alumina, LISICON (Lithium Super Ionic Conductor) compound, Li 2 SP 2 S 5 compound, Li 3 N, LiI, Li 5 NI 2 , Li 3 N-LiI-LiOH, LiSiO 4 , LiSiO 4 -LiI-LiOH, Li 2 SiS 3 , Li 4 SiO 4 , Li 4 SiO 4 -LiI-LiOH, Li 2 S, Li 2 S-SiS 2 , Li 2 S-GeS 2 , Li 2 SB 2 S 5 , Li 2 S-Al 2 S 2 , Li 2 O-Al 2 O 3 -TiO 2 -P 2 O 5 (LATP), CaF 2 , AgI, RbAg 4 I 5 , PVdF-HFP may comprise one or more selected from the group consisting of polymers, polyurethane-based polymers, polypropylene-based polymers and poly
  • the content of HFP in the PVdF-HFP may be 5% by weight or less, the shore hardness of the polyurethane-based polymer may be 75D or more, and the porosity of the polypropylene-based polymer may be 5-50%. If the Shore hardness is less than or equal to the above range, it may be difficult to physically inhibit the growth of dendrites. In addition, if the porosity is too low, there may be a capacity decrease due to the increase in resistance, and if too high, it may be difficult to suppress the dendrite growth.
  • the Young's modulus is an elastic modulus that indicates the degree of stretching and deformation of the object when the object is stretched from both sides.
  • the Young's modulus is also referred to as the length elastic modulus.
  • the second protective layer 130 physically suppresses the growth of dendrites, so It is preferable to have a Young's modulus as a physical property. Methods of measuring Young's modulus are known to those skilled in the art, and one exemplary instrument used to measure Young's modulus is the Universal Testing Machine.
  • the second protective layer 130 not only suppresses the growth of the dendrite but also has conductivity, it can smoothly transfer lithium ions to the electrode, thereby increasing battery life and improving battery performance.
  • the second protective layer 130 may be 1 ⁇ 10 ⁇ m.
  • the third protective layer 140 is formed on the second protective layer 130 and serves as a support for supporting the structure of the second protective layer 130. That is, the third protective layer 140 serves to physically support the second protective layer 130.
  • the third protective layer 140 has an ionic conductivity of 10 -5 S / Cm or more, the electrolyte absorption may be 150% by weight or less, preferably 10 to 150% by weight, PVdF-HFP polymer, polyurethane-based It may include one or more selected from the group consisting of a polymer and a polyacrylic polymer.
  • the HFP content of the PVdF-HFP may be 5 to 15% by weight, the shore hardness of the polyurethane-based polymer may be 80A to 75D, and the crosslinking density of the polyacrylic polymer may be 0.01 M / cm 3 or more.
  • the thickness of the third protective layer 140 may be 1 ⁇ 10 ⁇ m.
  • An electrolyte salt such as a lithium salt may be added to the polymer included in the first protective layer, the second protective layer, and the third protective layer to improve Li ion conductivity, and the lithium salt is typically used in an electrolyte for a lithium secondary battery. Those used may be used without limitation.
  • the formation method of the first protective layer 120, the second protective layer 130 and the third protective layer 140 is not particularly limited, and the PVdF-HFP polymer, polyurethane, polyacrylic and polypropylene polymer, etc.
  • the polymer or monomer may be mixed with a solvent coating solution and then formed by employing reaction sputtering, microgravure coating, comma coating, slot die coating, spray coating, dip coating, flow coating, and the like.
  • the solid electrolyte such as LiPON and LiBON may be used by mixing with a binder and the like in a powder state.
  • the negative electrode for a lithium secondary battery has a first protective layer containing PVdF-HFP of 20% by weight HFP, a second protective layer containing LiPON and 5% by weight of HFP on a lithium metal layer
  • the third protective layer including PVdF-HFP may be manufactured by laminating, and the lithium electrode having such a structure may effectively inhibit the growth of dendrites.
  • the lithium secondary battery electrode according to the present invention may have various widths and lengths depending on the shape of the battery. If necessary, a lithium secondary battery electrode manufactured in various widths may be wound and cut as necessary.
  • the present invention is a lithium metal layer
  • a negative electrode 100 for a lithium secondary battery comprising a; three or more layers independently selected from the group consisting of a dendrite growth inhibitory layer, a single ion conductive layer and a polymer layer.
  • the dendrites growth inhibiting layer means the second protective layer 130 and may include one or more selected from the group consisting of LiPON, LiBON, polyurethane-based polymers, polypropylene-based polymers, and polycarbonate-based polymers.
  • the single ion conductive layer may comprise inorganic, organic, and mixed organic-inorganic polymeric materials.
  • the term "single ion conducting layer” means a layer that selectively or exclusively allows passage of cations of a single load.
  • the single ion conductive layer has the ability to selectively or exclusively transfer cations, such as lithium ions, and may include, for example, the polymers disclosed in US Pat. No. 5,731,104 to Ventura et al.
  • the single ion conductive layer may contain a single ion conductive glass that is conductive to lithium ions.
  • suitable glasses are those that may be characterized as comprising a "modifier" portion and a "network” portion known in the art.
  • the modifier can typically be a metal oxide of a metal ion that is conductive in glass.
  • the network former may typically be a metal chalcogenide, such as a metal oxide or sulfide.
  • the single ion conductive layer is lithium silicate, lithium borate, lithium aluminate, lithium phosphate, lithium phosphorus oxynitride, lithium silicosulfide, lithium germanosulphide, lithium lanthanum oxide, lithium titanium oxide, lithium boro And a glassy layer containing a glassy material comprising at least one selected from the group consisting of sulfides, lithium aluminosulfides, and lithium phosphosulfides.
  • the single ion conducting layer may contain lithium phosphorus oxynitride. Electrolyte films of lithium phosphorus oxynitride are disclosed, for example, in US Pat. No. 5,569,520 (Bates).
  • the polymer layer may include one or more selected from the group consisting of, but not limited to, electrically conductive polymers, ion conductive polymers, sulfonated polymers, and hydrocarbon polymers.
  • electrically conductive polymers include, but are not limited to, poly (p-phenylene), polyacetylene, poly (phenylenevinylene), polyazulene, poly (perinaphthalene), polyacene and poly (naphthalene-2,6- Diyl), including those described in US Pat. No. 5,648,187 (Skotheim).
  • Suitable ion conductive polymers may also include ion conductive polymers known to be useful in solid polymer electrolytes and gel polymer electrolytes for lithium electrochemical cells such as polyethylene oxide.
  • Suitable sulfonated polymers may include sulfonated siloxane polymers, sulfonated polystyrene-ethylene-butylene polymers, and sulfonated polystyrene polymers.
  • Suitable hydrocarbon polymers may also include ethylene-propylene polymers, polystyrene polymers, and the like.
  • the polymer layer is also described in US Patent Application Serial No. 09 / 399,967 (co-applicant Ying) for protective coatings on alkyl acrylate, glycol acrylate, polyglycol acrylate, polyglycol vinyl ether, polyglycol divinyl ether and separator layers.
  • Crosslinked polymer materials formed from the polymerization of monomers including those described in "
  • the crosslinked polymer material may be polydivinyl poly (ethylene glycol).
  • the crosslinked polymeric material may further contain salts such as lithium salts to enhance ionic conductivity.
  • the multilayer polymer layer may include a crosslinked polymer.
  • the dendrite growth inhibition layer physically inhibits growth, and the single ion conductive layer and the polymer layer support and inhibit the growth layer. It can have a beneficial effect on suppression. Therefore, when the respective layers are stacked in combination, the effect of inhibiting dendrite growth may be improved.
  • the present invention provides a lithium secondary battery comprising the negative electrode (100).
  • Lithium secondary battery according to the present invention can be manufactured through a known technique carried out by those skilled in the art for the remaining configuration except for the structure and characteristics of the above-described negative electrode 100, will be described in detail below.
  • Common lithium secondary battery is a negative electrode; anode; Separation membrane interposed between them; And an electrolyte; and the negative electrode of the lithium secondary battery of the present invention may include a negative electrode including the multiple protective layer of the present invention.
  • the positive electrode may be manufactured in the form of a positive electrode by forming a composition including a positive electrode active material, a conductive material, and a binder on a positive electrode current collector.
  • the conductive material is a component for further improving the conductivity of the positive electrode active material.
  • the conductive material include graphite such as natural graphite and artificial 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 whiskers 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.
  • the binder maintains a positive electrode active material in a positive electrode current collector and has a function of organically connecting the positive electrode active materials.
  • PVDF polyvinylidene fluoride
  • PVA polyvinyl alcohol
  • CMC carboxymethyl cellulose
  • starch hydroxypropyl cellulose, regenerated cellulose
  • polyvinylpyrrolidone tetrafluoroethylene
  • polyethylene polypropylene
  • EPDM ethylene-propylene-diene polymer
  • sulfonated-EPDM styrene-butadiene rubber
  • fluorine Rubber these various copolymers, etc.
  • the positive electrode current collector is the same as described above in the negative electrode current collector, and generally, a thin aluminum plate may be used for the positive electrode current collector.
  • the positive electrode composition may be coated on a positive electrode current collector using a conventional method known in the art, and for example, a dipping method, a spray method, a roll court method, and a gravure printing method.
  • a conventional method known in the art, and for example, a dipping method, a spray method, a roll court method, and a gravure printing method.
  • Various methods may be used, such as a bar court method, a die coating method, a comma coating method, or a mixture thereof.
  • the positive electrode and the positive electrode composition which have undergone such a coating process are then dried through evaporation of a solvent or a dispersion medium, compactness of the coating film and adhesion between the coating film and the current collector. At this time, the drying is carried out according to a conventional method, which is not particularly limited.
  • the separator is not particularly limited in material, and physically separates the positive electrode and the negative electrode, and has electrolyte and ion permeability, and can be used without particular limitation as long as they are commonly used as separators in electrochemical devices, but are porous and visionary.
  • As the conductive or insulating material it is particularly desirable to have low resistance to ion migration of the electrolyte solution and excellent electrolyte electrolyte moisture content.
  • a polyolefin-based porous membrane or a nonwoven fabric may be used, but is not particularly limited thereto.
  • polyolefin-based porous membrane examples include polyethylene, polypropylene, polybutylene, polypentene, such as high density polyethylene, linear low density polyethylene, low density polyethylene, ultra high molecular weight polyethylene, respectively, or a mixture thereof There is a curtain.
  • the nonwoven fabric is, for example, polyphenyleneoxide, polyimide, polyamide, polycarbonate, polyethyleneterephthalate, polyethylenenaphthalate in addition to the aforementioned polyolefin-based nonwoven fabric.
  • Polybutyleneterephthalate, polyphenylenesulfide, polyacetal, polyethersulfone, polyetheretherketone, polyester, etc. alone or in combination
  • a nonwoven fabric formed of a polymer mixed therewith is possible, and the nonwoven fabric is a fiber form forming a porous web, and includes a spunbond or meltblown form composed of long fibers.
  • the thickness of the separator is not particularly limited, but is preferably in the range of 1 to 100 ⁇ m, more preferably in the range of 5 to 50 ⁇ m. When the thickness of the separator is less than 1 ⁇ m, mechanical properties may not be maintained. When the separator is more than 100 ⁇ m, the separator may act as a resistance layer, thereby degrading battery performance.
  • Pore size and porosity of the separator is not particularly limited, but the pore size is 0.1 to 50 ⁇ m, porosity is preferably 10 to 95%. If the pore size of the separator is less than 0.1 ⁇ m or porosity is less than 10%, the separator acts as a resistive layer, mechanical properties cannot be maintained when the pore size exceeds 50 ⁇ m or porosity exceeds 95% .
  • the electrolyte may be a nonaqueous electrolyte or a solid electrolyte which does not react with lithium metal, but is preferably a nonaqueous electrolyte and includes an electrolyte salt and an organic solvent.
  • the electrolyte salt contained in the nonaqueous electrolyte is a lithium salt.
  • the lithium salt may be used without limitation those conventionally used in the lithium secondary battery electrolyte.
  • For example is the above lithium salt anion F -, Cl -, Br - , I -, NO 3 -, N (CN) 2 -, BF 4 -, ClO 4 -, PF 6 -, (CF 3) 2 PF 4 -, (CF 3) 3 PF 3 -, (CF 3) 4 PF 2 -, (CF 3) 5 PF -, (CF 3) 6 P -, CF 3 SO 3 -, CF 3 CF 2 SO 3 - , (CF 3 SO 2) 2 N -, (FSO 2) 2 N -, CF 3 CF 2 (CF 3) 2 CO -, (CF 3 SO 2) 2 CH -, (SF 5) 3 C -, (CF 3 SO 2) 3 C - from the group consisting of -, CF 3 (CF
  • organic solvent included in the non-aqueous electrolyte those conventionally used in a lithium secondary battery electrolyte may be used without limitation, and for example, ethers, esters, amides, linear carbonates, cyclic carbonates, etc. may be used alone or in combination of two or more. Can be used. Among them, carbonate compounds which are typically cyclic carbonates, linear carbonates, or mixtures thereof may be included.
  • cyclic carbonate compound examples include ethylene carbonate (EC), propylene carbonate (PC), 1,2-butylene carbonate, 2,3-butylene carbonate, 1,2-pentylene carbonate, 2,3-pentylene carbonate, vinylene carbonate, vinylethylene carbonate and any one selected from the group consisting of halides thereof or mixtures of two or more thereof.
  • halides include, for example, fluoroethylene carbonate (FEC), but are not limited thereto.
  • linear carbonate compound may be any one selected from the group consisting of dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate, ethylmethyl carbonate (EMC), methylpropyl carbonate and ethylpropyl carbonate. Mixtures of two or more of them may be representatively used, but are not limited thereto.
  • ethylene carbonate and propylene carbonate which are cyclic carbonates among the carbonate-based organic solvents, have high dielectric constants and may dissociate lithium salts in the electrolyte more efficiently.
  • low viscosity, low dielectric constant linear carbonate mixed in an appropriate ratio it can be made an electrolyte having a higher electrical conductivity.
  • any one selected from the group consisting of dimethyl ether, diethyl ether, dipropyl ether, methylethyl ether, methylpropyl ether, and ethylpropyl ether, or a mixture of two or more thereof may be used. It is not limited to this.
  • esters in the organic solvent include methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, ⁇ -butyrolactone, ⁇ -valerolactone, ⁇ -caprolactone, ⁇ Any one or a mixture of two or more selected from the group consisting of -valerolactone and ⁇ -caprolactone may be used, but is not limited thereto.
  • the injection of the nonaqueous electrolyte may be performed at an appropriate step in the manufacturing process of the electrochemical device, depending on the manufacturing process and the required physical properties of the final product. That is, it may be applied before the electrochemical device assembly or the final step of the electrochemical device assembly.
  • the lithium secondary battery according to the present invention may be a lamination (stacking) and folding (folding) process of the separator and the electrode in addition to the winding (winding) which is a general process.
  • the case of the battery may be cylindrical, square, pouch type or coin type.
  • the lithium secondary battery including the negative electrode according to the present invention stably exhibits excellent discharge capacity, output characteristics, and capacity retention rate, portable devices such as mobile phones, notebook computers, digital cameras, and hybrid electric vehicles (hybrid) It is useful for electric vehicle fields such as electric vehicle (HEV).
  • HEV electric vehicle
  • the first protective layer was prepared by adding 20% by weight of PVdF-HFP to HFP in a solvent NMP to prepare a 20% by weight solution, followed by slot die coating on the lithium metal plate, and drying at 120 ° C. for 30 minutes to form a thickness of 2 ⁇ m.
  • the second protective layer was formed on the first protective layer by sputtering a solution containing LiPON to a thickness of 1 ⁇ m.
  • the third protective layer was prepared by adding 5 wt% PVdF-HFP of HFP to the solvent NMP to prepare a 10 wt% solution, and then drying at 120 ° C. for 30 minutes after slot die coating on the second protective layer to form a thickness of 2 ⁇ m. It was.
  • a cathode was prepared using LCO (LiCoO 2 ) as the cathode active material.
  • NMP N-methylpyrrolidone
  • LCO: Super-P: PVDF 95: 2.5: 2.5 by mixing in a weight ratio to prepare a slurry and coated on a 12 ⁇ m thick aluminum foil 70 ⁇ m thick
  • a positive electrode was prepared.
  • EC ethylene carbonate
  • DEC diethyl carbonate
  • DMC dimethyl carbonate
  • LiPF 6 1.0M an electrolyte solution containing 2% by weight of vinylene carbonate (VC) as an additive was injected to prepare a lithium secondary battery.
  • a first protective layer containing polyurethane On the lithium metal plate negative electrode having a thickness of 20 ⁇ m, a first protective layer containing polyurethane, a second protective layer containing LiPON, and a third protective layer containing 5 wt% of PVdF-HFP were formed.
  • the first protective layer was prepared by adding polyurethane (Shore hardness 80A) to the solvent NMP to prepare a 20% by weight solution, and then coating the die-die on the lithium metal plate and drying at 120 ° C. for 30 minutes to form a thickness of 2 ⁇ m.
  • polyurethane Shore hardness 80A
  • the second protective layer was formed on the first protective layer by sputtering a solution containing LiPON to a thickness of 1 ⁇ m.
  • the third protective layer was prepared by adding 5 wt% PVdF-HFP of HFP to the solvent NMP to prepare a 10 wt% solution, and then drying at 120 ° C. for 30 minutes after slot die coating on the second protective layer to form a thickness of 2 ⁇ m. It was.
  • a cathode was prepared using LCO (LiCoO 2 ) as the cathode active material.
  • NMP N-methylpyrrolidone
  • LCO: Super-P: PVDF 95: 2.5: 2.5 by mixing in a weight ratio to prepare a slurry and coated on a 12 ⁇ m thick aluminum foil 70 ⁇ m thick
  • a positive electrode was prepared.
  • EC ethylene carbonate
  • DEC diethyl carbonate
  • DMC dimethyl carbonate
  • LiPF 6 1.0M an electrolyte solution containing 2% by weight of vinylene carbonate (VC) as an additive was injected to prepare a lithium secondary battery.
  • a first protective layer containing 20 wt% of PVdF-HFP, a second protective layer containing LiBON, and a third protective layer including 5 wt% of PVdF-HFP were formed on the lithium metal plate anode having a thickness of 20 ⁇ m. It was.
  • the first protective layer was prepared by adding 20% by weight of PVdF-HFP to HFP in a solvent NMP to prepare a 20% by weight solution, followed by slot die coating on the lithium metal plate, and drying at 120 ° C. for 30 minutes to form a thickness of 2 ⁇ m.
  • the second protective layer was formed on the first protective layer by sputtering a solution containing LiBON to a thickness of 1 ⁇ m.
  • the third protective layer was prepared by adding 5 wt% PVdF-HFP of HFP to the solvent NMP to prepare a 10 wt% solution, and then drying at 120 ° C. for 30 minutes after slot die coating on the second protective layer to form a thickness of 2 ⁇ m. It was.
  • a cathode was prepared using LCO (LiCoO 2 ) as the cathode active material.
  • NMP N-methylpyrrolidone
  • LCO: Super-P: PVDF 95: 2.5: 2.5 by mixing in a weight ratio to prepare a slurry and coated on a 12 ⁇ m thick aluminum foil 70 ⁇ m thick
  • a positive electrode was prepared.
  • EC ethylene carbonate
  • DEC diethyl carbonate
  • DMC dimethyl carbonate
  • LiPF 6 1.0M an electrolyte solution containing 2% by weight of vinylene carbonate (VC) as an additive was injected to prepare a lithium secondary battery.
  • a first protective layer containing 20 wt% PVdF-HFP, a second protective layer including LiPON, and a third protective layer including polyurethane were formed.
  • the first protective layer was prepared by adding 20% by weight of PVdF-HFP to HFP in a solvent NMP to prepare a 20% by weight solution, followed by slot die coating on the lithium metal plate, and drying at 120 ° C. for 30 minutes to form a thickness of 2 ⁇ m.
  • the second protective layer was formed on the first protective layer by sputtering a solution containing LiPON to a thickness of 1 ⁇ m.
  • the third protective layer was prepared by adding polyurethane (Shore hardness 75D) to the solvent NMP to prepare a solution of 20% by weight, and after drying the slot die coating on the second protective layer for 30 minutes at 120 °C to form a thickness of 2 ⁇ m .
  • a cathode was prepared using LCO (LiCoO 2 ) as the cathode active material.
  • NMP N-methylpyrrolidone
  • LCO: Super-P: PVDF 95: 2.5: 2.5 by mixing in a weight ratio to prepare a slurry and coated on a 12 ⁇ m thick aluminum foil 70 ⁇ m thick
  • a positive electrode was prepared.
  • EC ethylene carbonate
  • DEC diethyl carbonate
  • DMC dimethyl carbonate
  • LiPF 6 1.0M an electrolyte solution containing 2% by weight of vinylene carbonate (VC) as an additive was injected to prepare a lithium secondary battery.
  • Example 1 The same procedure as in Example 1 was performed except that the first protective layer, the second protective layer, and the third protective layer were not manufactured and coated in Example 1.
  • Example 1 Except that the first protective layer was not prepared and coated in Example 1 was prepared in the same manner as in Example 1.
  • Example 1 Except that the second protective layer was not prepared and coated in Example 1 was prepared in the same manner as in Example 1.
  • Example 1 Except that the third protective layer was not prepared and coated in Example 1 was prepared in the same manner as in Example 1.
  • Example 1 Example 2 Example 3
  • Example 4 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 80% discharge capacity cycles 198 181 195 196 75 76 105 153
  • Comparative Example 2 without forming the first protective layer, the cell performance was not improved due to poor interface formation, and in Comparative Example 3 without forming the second protective layer, the dendrite growth was suppressed due to insufficient strength. Power fell.
  • Comparative Example 4 in which the third protective layer was not formed, the second protective layer was destroyed during the cycle and the performance of the battery was degraded because the pressure caused by the volume change due to the suppression of the dendrite growth of the second protective layer was not relieved.
  • Comparative Example 1 since the protective layer of the present invention was not formed, the cycle number reaching the discharge capacity of 80% was the smallest. That is, the battery of Example 1 of the present invention showed the best battery performance.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Materials Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Secondary Cells (AREA)
  • Battery Electrode And Active Subsutance (AREA)

Abstract

La présente invention concerne une électrode négative comprenant de multiples couches de protection et une batterie secondaire au lithium la comprenant, les multiples couches de protection empêchant physiquement la croissance de dendrites de lithium sur une surface d'électrode, et en même temps, étant susceptibles de transférer efficacement des ions lithium vers une électrode métallique au lithium et de présenter une excellente conductivité ionique, et par conséquent les couches de protection elles-mêmes ne s'appliquent pas en tant que couches de résistance, ce qui permet d'empêcher l'apparition d'une surtension lors de la charge/décharge, et d'empêcher ainsi la dégradation des performances de la batterie et de garantir la stabilité lors de l'attaque de la batterie.
PCT/KR2017/009807 2016-09-21 2017-09-07 Électrode négative comprenant de multiples couches de protection et batterie secondaire au lithium la comprenant WO2018056615A1 (fr)

Priority Applications (4)

Application Number Priority Date Filing Date Title
CN201780030524.7A CN109155396B (zh) 2016-09-21 2017-09-07 包含多重保护层的负极和包含该负极的锂二次电池
EP17853329.5A EP3428998B1 (fr) 2016-09-21 2017-09-07 Électrode négative comprenant de multiples couches de protection et batterie secondaire au lithium la comprenant
JP2018549464A JP6656718B2 (ja) 2016-09-21 2017-09-07 多重保護層を含む負極及びこれを含むリチウム二次電池
US16/089,978 US10957911B2 (en) 2016-09-21 2017-09-07 Negative electrode comprising multiple protection layers and lithium secondary battery comprising same

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KR10-2016-0120602 2016-09-21
KR20160120602 2016-09-21
KR10-2017-0092180 2017-07-20
KR1020170092180A KR102003307B1 (ko) 2016-09-21 2017-07-20 다중 보호층을 포함하는 음극 및 이를 포함하는 리튬이차전지

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CN109818048A (zh) * 2019-03-04 2019-05-28 江西星盈科技有限公司 全固态锂金属电池及其制备工艺
CN110707287A (zh) * 2018-07-09 2020-01-17 郑州宇通集团有限公司 一种金属锂负极及其制备方法和锂电池
WO2020026705A1 (fr) * 2018-07-30 2020-02-06 パナソニックＩｐマネジメント株式会社 Accumulateur au lithium
CN112166520A (zh) * 2018-06-15 2021-01-01 株式会社Lg化学 固体电解质膜和包含该固体电解质膜的固态电池
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CN113540401A (zh) * 2020-04-21 2021-10-22 华为技术有限公司 金属负极及其制备方法和二次电池
CN113540401B (zh) * 2020-04-21 2023-03-24 华为技术有限公司 金属负极及其制备方法和二次电池

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