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WO2019194429A1 - Électrode positive pour batterie rechargeable au lithium comprenant de la göthite et batterie rechargeable au lithium la comprenant - Google Patents

Électrode positive pour batterie rechargeable au lithium comprenant de la göthite et batterie rechargeable au lithium la comprenant Download PDF

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Publication number
WO2019194429A1
WO2019194429A1 PCT/KR2019/002956 KR2019002956W WO2019194429A1 WO 2019194429 A1 WO2019194429 A1 WO 2019194429A1 KR 2019002956 W KR2019002956 W KR 2019002956W WO 2019194429 A1 WO2019194429 A1 WO 2019194429A1
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Prior art keywords
lithium
secondary battery
positive electrode
lithium secondary
sulfur
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PCT/KR2019/002956
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English (en)
Korean (ko)
Inventor
한승훈
문정미
손권남
양두경
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LG Chem Ltd
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LG Chem Ltd
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Priority claimed from KR1020190028552A external-priority patent/KR20190117372A/ko
Application filed by LG Chem Ltd filed Critical LG Chem Ltd
Publication of WO2019194429A1 publication Critical patent/WO2019194429A1/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
    • 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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • 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 positive electrode for a lithium secondary battery including a gootite as a positive electrode additive and a lithium secondary battery having an improved lifespan.
  • Secondary batteries unlike primary batteries that can only be discharged once, have become an important electronic component of portable electronic devices since the 1990s as an electrical storage device capable of continuous charging and discharging.
  • the lithium ion secondary battery was commercialized by Sony, Japan in 1992, it has led the information age as a core component of portable electronic devices such as smartphones, digital cameras, and notebook computers.
  • lithium ion secondary batteries have been widely used in applications such as vacuum cleaners, power tools for electric tools, electric bicycles and electric scooters, and electric vehicles (EVs) and hybrid electric vehicles (hybrid electric vehicles).
  • EVs electric vehicles
  • hybrid electric vehicles hybrid electric vehicles
  • HEV vehicles
  • PHEVs Plug-in hybrid electric vehicles
  • ESS Electric Storage Systems
  • Lithium secondary battery is basically composed of materials such as positive electrode, electrolyte, negative electrode, etc. Among them, since positive and negative electrode materials determine the capacity of battery, lithium ion secondary battery is due to material limitations of positive and negative electrodes. Limited by capacity In particular, the secondary battery to be used for applications such as electric vehicles, PHEVs, so that the use of as long as possible after a single charge, the discharge capacity of the secondary battery is very important.
  • One of the biggest constraints on the sale of electric vehicles is that the distance that can be driven after a single charge is much shorter than that of a normal gasoline engine.
  • Lithium-sulfur secondary battery goes beyond the capacity limit determined by the insertion / decalation reaction of lithium ion layered metal oxide and graphite, which is the basic principle of conventional lithium ion secondary battery, and transition metal replacement and cost reduction It is a new high-capacity, low-cost battery system that can bring about.
  • a lithium-sulfur secondary battery is a lithium ion and the sulfur conversion (conversion) reaction at the anode - the theoretical capacity resulting from (S 8 + 16Li + + 16e ⁇ 8Li 2 S) reached 1,675 mAh / g anode is lithium metal (theoretical capacity: 3,860 mAh / g) enables ultra high capacity battery systems.
  • the discharge voltage is about 2.2 V, it theoretically shows an energy density of 2,600 Wh / kg based on the amount of the positive electrode and the negative electrode active material. This value is 6 to 7 times higher than the energy theoretical energy density of 400 Wh / kg of a commercial lithium secondary battery (LiCoO 2 / graphite) using a layered metal oxide and graphite.
  • Lithium-sulfur secondary batteries have been attracting attention as new high-capacity, eco-friendly and low-cost lithium secondary batteries since it is known that battery performance can be dramatically improved by forming nanocomposites around 2010. Phosphorus research is done.
  • the particle size is tens of nanometers. It is necessary to reduce the size to the following and conduct surface treatment with conductive materials. To this end, various chemicals (melt impregnation to nano-scale porous carbon nanostructures or metal oxide structures) and physical methods (high energy ball milling) are reported. It is becoming.
  • lithium-sulfur secondary batteries Another major problem associated with lithium-sulfur secondary batteries is the dissolution of lithium polysulfide, an intermediate of sulfur produced during discharge, into the electrolyte.
  • sulfur (S 8 ) continuously reacts with lithium ions such that S 8 ⁇ Li 2 S 8 ⁇ (Li 2 S 6 ) ⁇ Li 2 S 4 ⁇ Li 2 S 2 ⁇ Li 2 S, etc. (Phase) is continuously changed.
  • long chains of sulfur such as Li 2 S 8 and Li 2 S 4 (lithium polysulfide) are easily dissolved in general electrolytes used in lithium ion batteries. When this reaction occurs, not only the reversible cathode capacity is greatly reduced, but also the dissolved lithium polysulfide diffuses to the cathode, causing various side reactions.
  • Lithium polysulfide in particular, causes a shuttle reaction during the charging process, which causes the charging capacity to continuously increase, thereby rapidly decreasing the charge and discharge efficiency.
  • various methods have been proposed to solve this problem, and can be classified into a method of improving the electrolyte, a method of improving the surface of the negative electrode, and a method of improving the characteristics of the positive electrode.
  • the method of improving the electrolyte is to prevent the dissolution of polysulfide into the electrolyte using new electrolytes such as a functional liquid electrolyte, a polymer electrolyte, and an ionic liquid of a new composition, or to control the viscosity and the like to disperse the negative electrode. This is to control the shuttle reaction as much as possible.
  • electrolyte additives such as Li x NO y and Li x SO y are added to the surface of the lithium anode by adding an electrolyte additive such as LiNO 3 .
  • electrolyte additive such as LiNO 3 .
  • a method of forming a thick functional SEI layer on the surface of the lithium metal is actively conducted to control the shuttle reaction by improving the characteristics of the SEI formed on the surface of the anode.
  • methods to improve the characteristics of the anode include forming a coating layer on the surface of the anode particles to prevent the dissolution of polysulfide or adding a porous material that can catch the dissolved polysulfide.
  • the method of adding to the method, attaching a functional group capable of adsorbing lithium polysulfide on the surface of the carbon structure, and wrapping sulfur particles using graphene or graphene oxide, etc. have been proposed.
  • the present invention in order to solve the problem of lithium polysulfide elution occurring at the positive electrode side of the lithium-sulfur battery and to suppress side reactions with the electrolyte, gothite was introduced into the positive electrode of the lithium-sulfur battery.
  • the present invention was completed by confirming that the battery performance of the lithium-sulfur battery can be improved by solving the problem.
  • an object of the present invention is to provide a positive electrode additive for a lithium secondary battery that can solve the problem caused by lithium polysulfide.
  • Another object of the present invention is to provide a lithium secondary battery having the positive electrode and improved life characteristics of the battery.
  • the present invention provides a cathode for a lithium secondary battery containing a gootite.
  • One embodiment of the present invention is 1 to 15 parts by weight based on 100 parts by weight of the base solids contained in the positive electrode for lithium secondary batteries, the base solids include an active material, a conductive material and a binder.
  • the gothite is in a rod shape.
  • One embodiment of the present invention is that the diameter of the Gotite is in the form of a rod of 10 to 50 nm.
  • One embodiment of the present invention is that the length of the gothite is in the form of a rod of 50 to 500 nm.
  • One embodiment of the present invention is that the active material is a sulfur-carbon composite.
  • the lithium secondary battery positive electrode containing the gonite; cathode; A separator interposed between the anode and the cathode; It provides a lithium secondary battery comprising a; and an electrolyte.
  • the gothite according to the present invention When the gothite according to the present invention is applied to a positive electrode of a lithium secondary battery, especially a lithium-sulfur battery, it adsorbs lithium polysulfide generated during charging and discharging of the lithium-sulfur battery to increase the reactivity of the lithium-sulfur battery positive electrode. Suppresses side reactions with the electrolyte.
  • the lithium-sulfur battery equipped with the positive electrode including the gothite does not reduce the capacity of sulfur, and thus can realize a high capacity battery and stably apply sulfur by high loading, and there is no problem such as shorting or heating of the battery. Stability is improved.
  • the lithium secondary battery including the lithium-sulfur battery has the advantage of high charging and discharging efficiency of the battery and improved life characteristics.
  • FIG 1 and 2 show a scanning electron microscope (SEM) image of the gootite according to the present invention.
  • Figure 3 shows the results of the X-ray diffraction analysis (XRD) of the gootite in accordance with the present invention.
  • Figure 4 shows a scanning electron microscope (SEM) image of the lepidocrosite according to a comparative example of the present invention.
  • FIG. 5 shows the results of X-ray diffraction analysis (XRD) of the lepidocrosite according to a comparative example of the present invention.
  • Figure 6 shows the color change results of the lithium polysulfide adsorption experiment of gothite according to the present invention.
  • FIG. 7 shows discharge capacity measurement results of a lithium-sulfur battery including a positive electrode according to an exemplary embodiment of the present invention.
  • FIG. 8 shows the life characteristics measurement results of a lithium-sulfur battery including a positive electrode according to an embodiment of the present invention.
  • composite refers to a substance in which two or more materials are combined to form physically and chemically different phases and express more effective functions.
  • the present invention supplements the shortcomings of the conventional lithium-sulfur battery positive electrode, and provides a lithium secondary battery positive electrode which is improved in the problem of continuous degradation of the electrode due to the dissolution and shuttle phenomenon of lithium polysulfide (polysulfide) and reduction of discharge capacity.
  • the positive electrode for a lithium secondary battery provided by the present invention includes an active material, a conductive material, and a binder, and is characterized in that Gothite ( ⁇ -FeOOH) is applied (included) as a positive electrode additive.
  • the gothite is included in the positive electrode of the lithium secondary battery, especially lithium-sulfur battery in the present invention, by adsorbing lithium polysulfide, the lithium polysulfide is transferred to the negative electrode to reduce the life of the lithium-sulfur battery By reducing and suppressing the reduced reactivity due to lithium polysulfide, it is possible to increase the discharge capacity of the lithium-sulfur battery including the positive electrode, and furthermore, to improve the life of the battery.
  • the gothite contained in the positive electrode for a lithium secondary battery according to the present invention may preferably be prepared by reacting Fe (NO 3 ) 3 ⁇ 9H 2 O with N 2 H 4 ⁇ H 2 O. Since the reaction proceeds using hydrazine, the reaction solution maintains a high pH. First, after Fe (OH) 3 is generated, goatite is ⁇ -FeOOH is produced.
  • Goatite may be prepared by reacting 0.1 to 0.3M of N 2 H 4 .H 2 O solution with 0.04 to 0.08M of Fe (NO 3 ) 3 .9H 2 O.
  • the reaction can be prepared by mixing Fe (NO 3 ) 3 ⁇ 9H 2 O and N 2 H 4 ⁇ H 2 O aqueous solution within 10 to 120 seconds.
  • Fe (OH) 3 may be rapidly formed at a high pH to generate particles having a large particle size.
  • phases of the first reacted material and the later reacted material may be produced. As the phases may be different, appropriate control over the reaction rates in this range is required for the production of crystalline pure gothite.
  • the reaction may proceed for 24 hours at 80 ° C. for 2 hours.
  • the reaction can be reacted by stirring the Fe (NO 3 ) 3 ⁇ 9H 2 O aqueous solution and N 2 H 4 ⁇ H 2 O aqueous solution at 300 to 500rpm. Thereafter, the resulting gothite is filtered through a filter paper to allow sufficient air to flow therein, followed by drying at 80 ° C. for 6 to 12 hours to prepare gothite.
  • the gothite produced by the reaction may be crystalline.
  • FIGS 1 and 2 show scanning electron microscope (SEM) images of gothite ( ⁇ -FeOOH) prepared by the above method.
  • SEM scanning electron microscope
  • Goatite of the 'rod shape' (rod shape) prepared according to the manufacturing method according to the present invention may have a diameter of 10 to 50 nm, and a length of 50 to 500 nm.
  • Figure 3 shows the X-ray diffraction analysis (XRD) data results of the gootite prepared by the above production method.
  • XRD X-ray diffraction analysis
  • the effective (significant or effective) peak refers to a peak that is repeatedly detected in substantially the same pattern in XRD data without being greatly influenced by the analysis conditions or the performer of the analysis. It means a peak having a height, intensity, intensity, etc., which may be 1.5 times or more, preferably 2 times or more, more preferably 2.5 times or more, relative to a background level (backgound level).
  • the present invention provides a positive electrode for a lithium secondary battery containing gootite.
  • the positive electrode of the lithium secondary battery may be a base solid content including an active material, a conductive material and a binder on the current collector, it may be preferable to use aluminum, nickel and the like excellent in the current collector.
  • the gothite may be included in the positive electrode for a lithium secondary battery as an amount of 1 to 15 parts by weight based on 100 parts by weight of the base solids including the active material, the conductive material, and the binder, and preferably 1 to 10 parts by weight. It may be included as. If it is less than the lower limit of the numerical range, the adsorption effect of the polysulfide may be insignificant, and if the upper limit is exceeded, the capacity of the electrode may be reduced and may not meet the purpose of increasing the energy density.
  • the gootite may be used gothite prepared by the production method proposed in the present invention.
  • the gothite may be crystalline, may have a diameter of 10 to 50 nm, and may have a length of 50 to 500 nm. If the diameter and length are less than the above range, the specific surface area of the particles may increase, making it difficult to manufacture an electrode slurry of the lithium secondary battery, and if the range exceeds the above range, the activity of the gothite may decrease.
  • S 8 elemental sulfur
  • the positive electrode for a lithium secondary battery according to the present invention may preferably include an active material of a sulfur-carbon composite, and since the sulfur material alone is not electrically conductive, it may be used in combination with a conductive material.
  • the addition of goctite according to the invention does not affect the maintenance of this sulfur-carbon composite structure.
  • the carbon of the sulfur-carbon composite according to the present invention may have any porous structure or high specific surface area as long as it is commonly used in the art.
  • the porous carbon material includes graphite; Graphene; Carbon blacks such as denka black, acetylene black, ketjen black, channel black, furnace black, lamp black, and summer black; Carbon nanotubes (CNT) such as single-walled carbon nanotubes (SWCNT) and multi-walled carbon nanotubes (MWCNT); Carbon fibers such as graphite nanofibers (GNF), carbon nanofibers (CNF), and activated carbon fibers (ACF); And it may be one or more selected from the group consisting of activated carbon, but is not limited thereto, and the form is spherical, rod-shaped, needle-shaped, plate-shaped, tubular or bulk type, as long as it is commonly used in lithium secondary batteries, especially lithium-sulfur batteries It can be used without limitation.
  • the active material is preferably 50 to 95 parts by weight of 100 parts by weight of the base solids, and more preferably 70 parts by weight. If the active material is included below the range, it may be difficult to sufficiently exhibit the reaction of the electrode, and even if the active material is included above the range, the amount of the other conductive material and the binder is relatively insufficient and thus it is difficult to exert sufficient electrode reaction. It is desirable to determine the appropriate content within the above range.
  • the conductive material electrically connects the electrolyte and the positive electrode active material, and acts as a path for electrons to move from the current collector to the sulfur, causing chemical changes in the battery. If it does not have a porosity and conductivity, it will not specifically limit.
  • Graphite-based materials such as, for example, KS6; Carbon blacks such as Super-P, carbon black, denka black, acetylene black, ketjen black, channel black, furnace black, lamp black and summer black; Carbon derivatives such as fullerene; Conductive fibers such as carbon fibers and metal fibers; Metal powders such as carbon fluoride powder, aluminum powder and nickel powder; Or conductive polymers such as polyaniline, polythiophene, polyacetylene, and polypyrrole may be used alone or in combination.
  • the conductive material is preferably 1 to 10 parts by weight of 100 parts by weight of the base solids, preferably 5 parts by weight. If the content of the conductive material included in the electrode is less than the above range, the unreacted portion of sulfur in the electrode increases, eventually causing a decrease in capacity. If the content exceeds the above range, the high efficiency discharge characteristics and the charge and discharge cycle life are adversely affected. It is desirable to determine the appropriate content within the above range because it will have a.
  • the binder is a material that is included in order to adhere the slurry composition of the base solids, which form the positive electrode, to the current collector.
  • All binders known in the art can be used, unless otherwise specified, preferably poly (vinyl) acetate, polyvinyl alcohol, polyethylene oxide, polyvinyl pyrrolidone, alkylated polyethylene oxide, crosslinked polyethylene oxide , Polyvinyl ether, poly (methyl methacrylate), polyvinylidene fluoride (PVdF), polyhexafluoropropylene, copolymer of polyvinylidene fluoride (trade name: Kynar), poly (ethyl acrylate), poly Tetrafluoroethylene polyvinyl chloride, polytetrafluoroethylene, polyacrylonitrile, polyvinylpyridine, polystyrene, carboxymethyl cellulose, siloxane-based such as polydimethylsiloxane, styrene
  • the binder may be composed of 1 to 10 parts by weight of 100 parts by weight of the base composition included in the electrode, preferably about 5 parts by weight. If the content of the binder resin is less than the above range, the physical properties of the positive electrode may be deteriorated, so that the positive electrode active material and the conductive material may be dropped. If the content of the binder resin is greater than the above range, the ratio of the active material and the conductive material in the positive electrode may be relatively reduced, thereby reducing battery capacity. Therefore, it is preferable to determine the appropriate content within the above-mentioned range.
  • the positive electrode including the gothite and the base solids may be manufactured according to a conventional method.
  • a slurry may be prepared by mixing and stirring a solvent, a binder, a conductive material, and a dispersant in a positive electrode active material, and then applying (coating) to a current collector of a metal material, compressing, and drying the positive electrode to prepare a positive electrode.
  • the gothite is dispersed in a solvent, and the obtained solution is mixed with an active material, a conductive material, and a binder to obtain a slurry composition for forming a positive electrode.
  • the slurry composition is coated on a current collector and then dried to complete a positive electrode.
  • it can be manufactured by compression molding the current collector in order to improve the electrode density.
  • the method of coating the slurry for example, doctor blade coating, dip coating, gravure coating, slit die coating, spin coating It can be prepared by coating, comma coating, bar coating, reverse roll coating, screen coating, cap coating, and the like.
  • a positive electrode active material, a binder, and a conductive material may be uniformly dispersed, as well as those which can be easily dispersed to gothite.
  • water is most preferable as an aqueous solvent, and in this case, the water may be secondary distilled water (DW) or tertiary distilled water (DIW).
  • DIW tertiary distilled water
  • the present invention is not limited thereto, and if necessary, lower alcohols that can be easily mixed with water may be used.
  • the lower alcohols include methanol, ethanol, propanol, isopropanol, butanol, and the like. Preferably, they may be used in combination with water.
  • the present invention provides a lithium secondary battery comprising a separator and an electrolyte interposed between the positive electrode, the negative electrode, the positive electrode and the negative electrode for a lithium secondary battery including the goctite.
  • the negative electrode, the separator and the electrolyte may be composed of conventional materials that can be used in the lithium secondary battery.
  • the negative electrode is a material capable of reversibly intercalating or deintercalating lithium ions (Li + ) as an active material, a material capable of reacting with lithium ions to reversibly form a lithium-containing compound, lithium metal Or lithium alloys.
  • the material capable of reversibly occluding or releasing the lithium ions (Li + ) may be, for example, crystalline carbon, amorphous carbon or a mixture thereof.
  • the material capable of reacting with the lithium ions (Li + ) to form a lithium-containing compound reversibly may be, for example, tin oxide, titanium nitrate or silicon.
  • the lithium alloy may be, for example, an alloy of lithium and a metal selected from the group consisting of Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Ba, Ra, Al, and Sn.
  • the negative electrode may optionally further include a binder together with the negative electrode active material.
  • the binder serves to paste the negative electrode active material, mutual adhesion between the active materials, adhesion between the active material and the current collector, and buffer effect on the expansion and contraction of the active material.
  • the binder is the same as described above.
  • the negative electrode may further include a current collector for supporting a negative electrode active layer including a negative electrode active material and a binder.
  • the current collector may be specifically selected from the group consisting of copper, aluminum, stainless steel, titanium, silver, palladium, nickel, alloys thereof, and combinations thereof.
  • the stainless steel may be surface treated with carbon, nickel, titanium, or silver, and an aluminum-cadmium alloy may be used as the alloy.
  • calcined carbon, a nonconductive polymer surface-treated with a conductive agent, or a conductive polymer may be used.
  • the negative electrode may be a thin film of lithium metal.
  • the separator is a material that allows the transport of lithium ions between the positive electrode and the negative electrode while separating or insulated from each other, if used as a separator in a conventional lithium secondary battery can be used without particular limitation, in particular, the ion of the electrolyte It is desirable to have a low resistance to migration and excellent electrolyte-moisture capability.
  • the separator material may be a porous, non-conductive or insulating material, for example, an independent member such as a film, or a coating layer added to the anode and / or the cathode.
  • a porous polymer film made of a polyolefin-based polymer such as ethylene homopolymer, propylene homopolymer, ethylene / butene copolymer, ethylene / hexene copolymer, ethylene / methacrylate copolymer, etc. It may be used as a lamination or or a conventional porous non-woven fabric, for example, a non-woven fabric made of glass fibers, polyethylene terephthalate fibers of high melting point, etc. may be used, but is not necessarily limited thereto.
  • a polyolefin-based polymer such as ethylene homopolymer, propylene homopolymer, ethylene / butene copolymer, ethylene / hexene copolymer, ethylene / methacrylate copolymer, etc. It may be used as a lamination or or a conventional porous non-woven fabric, for example, a non-woven fabric made of glass fibers, polyethylene tere
  • the electrolyte is a non-aqueous electrolyte containing a lithium salt and is composed of a lithium salt and an electrolyte, and a non-aqueous organic solvent, an organic solid electrolyte, an inorganic solid electrolyte, and the like are used as the electrolyte.
  • the lithium salt is a material that can be easily dissolved in a non-aqueous organic solvent, for example, LiCl, LiBr, LiI, LiClO 4 , LiBF 4 , LiB 10 Cl 10 , LiB (Ph) 4, LiPF 6 , LiCF 3 SO 3 , LiCF 3 CO 2, LiAsF 6, LiSbF 6, LiAlCl 4, LiSO 3 CH 3, LiSO 3 CF 3, LiSCN, LiC (CF 3 SO 2) 3, LiN (CF 3 SO 2) 2, chloroborane lithium, lower aliphatic It may be at least one from the group consisting of lithium carbonate, lithium phenyl borate, imide.
  • a non-aqueous organic solvent for example, LiCl, LiBr, LiI, LiClO 4 , LiBF 4 , LiB 10 Cl 10 , LiB (Ph) 4, LiPF 6 , LiCF 3 SO 3 , LiCF 3 CO 2, LiAsF 6, LiSbF 6, LiAlCl 4, LiSO 3
  • the concentration of the lithium salt is preferably 0.2-2 M, depending on several factors such as the exact composition of the electrolyte mixture, the solubility of the salt, the conductivity of the dissolved salt, the charging and discharging conditions of the cell, the operating temperature and other factors known in the lithium battery art. It may be 0.6 to 2M, more preferably 0.7 to 1.7M. If the concentration of the lithium salt is less than the above range, the conductivity of the electrolyte may be lowered and the performance of the electrolyte may be lowered. If the concentration of the lithium salt is less than the above range, the viscosity of the electrolyte may be increased, thereby reducing the mobility of lithium ions (Li + ), and thus within the above range. It is desirable to select the appropriate concentration.
  • the non-aqueous organic solvent is a material capable of dissolving lithium salts, preferably 1,2-dimethoxyethane, 1,2-diethoxyethane, 1,2-dibutoxyethane, dioxolane (Dioxolane, DOL ), 1,4-dioxane, tetrahydrofuran, 2-methyltetrahydrofuran, dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), methyl propyl carbonate (MPC), ethyl propyl carbonate , Dipropyl carbonate, butyl ethyl carbonate, ethyl propanoate (EP), toluene, xylene, dimethyl ether (DME), diethyl ether, triethylene glycol monomethyl ether (TEGME), Diglyme, tetraglyme, hexamethyl phosphoric triamide, gamma butyrolactone (GB
  • organic solid electrolyte preferably, a polyethylene derivative, a polyethylene oxide derivative, a polypropylene oxide derivative, a phosphate ester polymer, poly etchation lysine, polyester sulfide, polyvinyl alcohol, polyvinylidene fluoride, ionic Polymers containing dissociation groups and the like can be used.
  • the inorganic solid electrolyte of the present invention is preferably 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 Nitrides, halides, sulfates, and the like of Li, such as Li 4 SiO 4 -LiI-LiOH, Li 3 PO 4 -Li 2 S-SiS 2 , and the like, may be used.
  • the lithium secondary battery may be those commonly used in the art, such as a lithium-sulfur battery and a lithium metal battery, and may exemplarily represent a lithium-sulfur battery that best meets the spirit of the present invention.
  • the shape of the lithium secondary battery is not particularly limited, and may be, for example, jelly-roll type, stack type, stack-fold type (ex: stack-Z-fold type), or lamination-stack type, among them, stack-fold type. This may be desirable.
  • the electrode assembly After manufacturing an electrode assembly in which the positive electrode, the separator, and the negative electrode are sequentially stacked, the electrode assembly may be placed in a battery case, and then the electrolyte may be injected into the upper part of the case and sealed assembled with a cap plate and a gasket to manufacture a lithium secondary battery.
  • the lithium secondary battery may be classified into a cylindrical shape, a square shape, a coin type, a pouch type, and the like, and may be classified into a bulk type and a thin film type according to its size. Since the structure and manufacturing method of these batteries are well known in the art, detailed description thereof will be omitted.
  • the lithium secondary battery according to the present invention which is configured as described above, lithium-sulfur battery, including the gothite to adsorb lithium polysulfide generated during charge and discharge of the lithium-sulfur battery to increase the reactivity of the battery positive electrode Ultimately, it has the effect of increasing the discharge capacity and life of the battery.
  • the gothite prepared from Preparation Example 1 was added to 10 parts by weight of the total weight (100 parts by weight) and dispersed in a base solid (active material, conductive material, and binder) into which gothite was added to water as a solvent. .
  • a total of 100 parts by weight of the base solids that is, 90 parts by weight of sulfur-carbon composite (S / C 7: 3) as the active material, 5 parts by weight of denca black as the conductive material, and styrene butadiene rubber / 5 parts by weight of carboxymethyl cellulose (SBR / CMC 7: 3) was added and mixed to prepare a positive electrode slurry composition.
  • the prepared positive electrode slurry composition was coated on a current collector (Al Foil) and dried at 50 ° C. for 12 hours to prepare a positive electrode.
  • the loading amount was 3.5mAh / cm 2
  • the porosity of the electrode was 60%.
  • a lithium-sulfur battery in the form of a coin cell including a negative electrode, a separator and an electrolyte was prepared as follows. Specifically, the anode was punched out using a 14 phi circular electrode, and the polyethylene (PE) separator was punched out with 16 phi as a 19 phi and 150 um lithium metal as a cathode.
  • PE polyethylene
  • a coin-cell lithium-sulfur battery was prepared in the same manner as in Example 1, except that no gothite was added to the positive electrode.
  • a coin-coated lithium-sulfur battery was prepared in the same manner as in Example 1, except that 10 parts by weight of the lepidocrocite prepared from Preparation Example 2 was added to 100 parts by weight of the base solid instead of the gootite. It was.
  • SEM analysis (S-4800 FE-SEM of Hitachi, Ltd.) was respectively performed on the goitite prepared from Preparation Example 1 and the lepidocrosite prepared from Preparation Example 2.
  • 1 and 2 are SEM images of the gothite prepared in Preparation Example 1
  • FIG. 4 is an SEM image of the repidocrosite prepared in Preparation Example 2.
  • FIG. 5 is a graph showing an XRD analysis result for the lepidocrocite prepared in Preparation Example 2.
  • Example 7 Using the lithium-sulfur batteries prepared in Example 1, Comparative Examples 1 and 2, the discharge capacity according to the type and type of the positive electrode additive was measured and shown in FIG. 7. At this time, the measurement current was 0.1C and the voltage range was 1.8-2.5V.
  • the lithium-sulfur battery of Example 1 in which the gothite was contained in the positive electrode had an initial discharge capacity as compared with the lithium-sulfur battery of Comparative Example 1 in which the gothite was not contained in the positive electrode, as shown in FIG. 7. It can be seen that about 100 mAh / g is higher. In addition, it was confirmed that the initial discharge capacity of the battery was also higher than that of Comparative Example 1 in the case of Comparative Example 2 in which repidocrosite was applied instead of gootite. Accordingly, it was found that both gothite and lepidocrocite are effective for increasing the initial discharge capacity of lithium-sulfur batteries.
  • Comparative Examples 1 and 2 was measured in the life cycle characteristics of the battery shown in Figure 8 shown. In the voltage range of 1.8 to 2.5V, 0.1C discharge / 0.1C charge 3 Cycle, 0.2C discharge / 0.2C charge 3 Cycle, 0.5C discharge / 0.3C charge was repeated repeatedly.
  • the battery according to Comparative Example 2 degenerated at about 120 cycles, while the battery according to Example 1 did not degenerate even at 160 cycles or more. As a result, it can be seen that the lithium-sulfur battery including gotite in the positive electrode has excellent life characteristics according to cycles.

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  • Electrochemistry (AREA)
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Abstract

La présente invention concerne une électrode positive pour une batterie rechargeable au lithium comprenant de la göthite en tant qu'additif et une batterie rechargeable au lithium la comprenant. Dans une batterie lithium-soufre, en particulier, parmi les batteries rechargeables au lithium comprenant une électrode positive à laquelle de la göthite est appliquée, la göthite peut adsorber le polysulfure de lithium (LiPS) généré dans le processus de charge et de décharge de la batterie, ce qui permet d'augmenter l'efficacité de charge et de décharge de la batterie et d'améliorer la longévité.
PCT/KR2019/002956 2018-04-06 2019-03-14 Électrode positive pour batterie rechargeable au lithium comprenant de la göthite et batterie rechargeable au lithium la comprenant Ceased WO2019194429A1 (fr)

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KR10-2018-0040389 2018-04-06
KR20180040389 2018-04-06
KR10-2019-0028552 2019-03-13
KR1020190028552A KR20190117372A (ko) 2018-04-06 2019-03-13 괴타이트를 포함하는 리튬 이차전지용 양극 및 이를 구비한 리튬 이차전지

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006107763A (ja) * 2004-09-30 2006-04-20 Gs Yuasa Corporation:Kk オキシ水酸化鉄の製造方法およびそれを含む電極を備えた非水電解質電気化学セル
KR20140097797A (ko) * 2013-01-30 2014-08-07 광주과학기술원 금속-환원 박테리아를 이용한 생합성 침철석 나노와이어의 제조방법 및 이의 용도
KR20170032190A (ko) * 2015-09-14 2017-03-22 주식회사 엘지화학 리튬 황 전지용 양극, 이의 제조방법 및 이를 포함하는 리튬 황 전지
CN106745323A (zh) * 2016-12-09 2017-05-31 太原理工大学 一种铁硫化合物及其复合材料的制备方法
WO2017109014A1 (fr) * 2015-12-22 2017-06-29 Rhodia Operations Matière active positive pour batterie rechargeable au lithium-soufre

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006107763A (ja) * 2004-09-30 2006-04-20 Gs Yuasa Corporation:Kk オキシ水酸化鉄の製造方法およびそれを含む電極を備えた非水電解質電気化学セル
KR20140097797A (ko) * 2013-01-30 2014-08-07 광주과학기술원 금속-환원 박테리아를 이용한 생합성 침철석 나노와이어의 제조방법 및 이의 용도
KR20170032190A (ko) * 2015-09-14 2017-03-22 주식회사 엘지화학 리튬 황 전지용 양극, 이의 제조방법 및 이를 포함하는 리튬 황 전지
WO2017109014A1 (fr) * 2015-12-22 2017-06-29 Rhodia Operations Matière active positive pour batterie rechargeable au lithium-soufre
CN106745323A (zh) * 2016-12-09 2017-05-31 太原理工大学 一种铁硫化合物及其复合材料的制备方法

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