WO2014021691A1

WO2014021691A1 - Cathode material, cathode assembly, secondary battery, and method for manufacturing same

Info

Publication number: WO2014021691A1
Application number: PCT/KR2013/007018
Authority: WO
Inventors: 홍영진; 김철환; 이재훈
Original assignee: (주)오렌지파워
Priority date: 2012-08-03
Filing date: 2013-08-04
Publication date: 2014-02-06

Abstract

Embodiments of the present invention relate to a cathode material, a cathode assembly, a secondary battery, and a method for manufacturing same. The cathode material, according to one embodiment of the present invention, can be a linear cathode material comprising: a conductive wire; a lithium metal layer which coats the conductive wire; and a carbon layer which coats the lithium metal layer. Also, the cathode material according to one embodiment of the present invention comprises: a planar current collector for a base material; a lithium metal layer which coats the current collector; and a carbon layer which coats the lithium metal layer.

Description

Negative material, negative electrode assembly, secondary battery and manufacturing method thereof

The present invention relates to a secondary battery technology, and more particularly, to a negative electrode material, a negative electrode assembly, a secondary battery and a method of manufacturing the same.

Recently, the demand for secondary batteries such as lithium batteries, lithium ion batteries, and lithium ion polymer batteries has been greatly increased. A secondary battery is a battery which can be charged and discharged by using an electrode material having excellent reversibility, and is a nickel-hydrogen (Ni-MH) battery, a lithium (Li) battery, a lithium ion (Li-ion) battery, etc. according to a positive electrode and a negative electrode active material. It can be divided into. Such secondary batteries are increasingly being applied as a power source for smart devices such as smart phones, portable computers, and electronic devices such as electronic paper, or vehicles such as bicycles and electric vehicles.

When lithium is used as the negative electrode active material, the standard electrode potential of lithium metal can be used as electromotive force as it is, and thus a high output battery can be obtained, and the capacity of the battery can be approached to the theoretical capacity, thereby maximizing energy density. However, in the case of a lithium active material, there is a problem in that dendritic lithium (lithium dendrite), which is a crystalline protrusion, grows in a negative electrode according to a chemical reaction caused by charging and discharging of a battery. The dendritic lithium blocks the pores of the separator inside the battery to block the movement of ionic materials, thereby reducing the charge / discharge efficiency. When the dendritic lithium grows excessively, the dendritic lithium penetrates the separator to provide a positive electrode and The negative electrode can be shorted.

Due to such a problem of the lithium active material, a carbon-based material having excellent cycle characteristics and a theoretical capacity of 372 mAh / g as a negative electrode active material of a secondary battery has been widely commercialized. However, as the application of secondary batteries expands to not only low power but also medium and high power fields, there is a demand for higher capacity and higher output of secondary batteries. Accordingly, lithium itself having a theoretical capacity of 8 times higher than carbon-based materials is required. What is needed is a technique for using as a negative electrode active material.

Accordingly, the technical problem to be solved by the present invention is to use a lithium itself as a negative electrode active material, to provide a negative electrode material having high capacity and high output, but also having reliability and improved lifespan.

Another technical problem to be solved by the present invention is to provide a negative electrode assembly having the aforementioned advantages.

Another technical problem to be solved by the present invention is to provide a secondary battery having a high energy density while having the advantages described above.

In addition, another technical problem to be solved by the present invention is to provide a negative electrode assembly having the above advantages and a manufacturing method capable of forming a large amount of batteries quickly and economically.

The negative electrode material according to an embodiment of the present invention for solving the technical problem, the conductive wire; A lithium metal layer coating the conductive wire; And a carbon layer coating the lithium metal layer. The linear negative electrode material may further include a separator for coating the carbon layer on the carbon layer.

The separator may include a plurality of pores exposing the surface of the carbon layer. The conductive wires may comprise metal fibers. The metal fibers may be any one of stainless steel, nickel, titanium, tantalum, copper, gold, platinum, ruthenium, silver, tin, zinc, tungsten, chromium, vanadium, molybdenum, zirconium, yttrium, antimony, and alloys thereof. Or combinations thereof. In another embodiment, the conductive wires may include any one or a combination of conductive polymers, composite fibers coated with a conductive layer on a non-conductive polymer, and carbon fibers.

According to another aspect of the present invention, there is provided a cathode assembly, including: conductive wires extending in at least two different directions to form a three-dimensional solid body having pores; A lithium metal layer coating the conductive wire; And it may include a carbon layer coating the lithium metal layer. The negative electrode assembly may further include a separator for coating the carbon layer. The separator may include a plurality of pores exposing the surface of the carbon layer.

The lithium metal layer may be formed to extend onto adjacent different conductive wires. In addition, the carbon layer may be formed to extend on adjacent different conductive wires. Similarly, the separator may be formed to extend onto carbon layers on adjacent different conductive wires. The conductive wires may have a nonwoven structure. Alternatively, the conductive wires may have a woven structure.

The secondary battery according to an embodiment of the present invention for solving the above another technical problem, to form a three-dimensional solid with pores extending in at least two different directions and has a plurality of linear negative electrode material which is energized with each other ; A positive electrode including positive electrode active materials inserted into the pores of the negative electrode and a positive electrode current collector electrically connected to the positive electrode active materials; And a separator for separating the cathode and the anode.

The cathode includes conductive wires forming the three-dimensional solid; A lithium metal layer coating the conductive wire; And it may include a carbon layer coating the lithium metal layer. In addition, the separator may be formed to coat the carbon layer of the cathode.

In some embodiments, the conductive wires can have a nonwoven structure. In another embodiment, the conductive wires may have a woven structure.

In some embodiments, the positive electrode current collector may include a conductive wire for positive electrode extending into the pores of the three-dimensional solid. The anode conductive wire may include a metal fiber. The positive electrode current collector may include a conductive foil surrounding at least a portion of the three-dimensional solid surface.

According to another aspect of the present invention, there is provided a method of manufacturing a negative electrode assembly, including: providing conductive wires; And forming a multilayer structure including a lithium metal layer and a carbon layer coating the lithium metal layer on the conductive wires.

The forming of the multilayer structure may include forming the lithium metal layer by a plating method or a reduction method in solution using a lithium-containing precursor; And forming the carbon layer on the lithium metal layer. In another embodiment, the forming of the multilayer structure may include forming a lithium-containing intermediate product layer using a lithium-containing precursor on the conductive wire; Forming a carbon-containing layer on the lithium-containing intermediate product layer; And heating the resultant product on which the carbon-containing layer is formed to simultaneously form the lithium metal layer and the carbon layer through thermal decomposition of the carbon-containing layer and a carbon reduction reaction of the lithium-containing intermediate product layer. In another embodiment, the forming of the multilayer structure may include forming a carbon layer by heat treating a carbon-containing layer formed on the conductive wire, and cooling to form a gap between the conductive wire and the carbon layer; And forming the lithium metal layer on the conductive wire while filling the pores by transferring lithium ions onto the conductive wire through the carbon layer by the electroplating method.

In some embodiments, the method may further include forming a separator on the carbon layer, the separator having a plurality of pores exposing the surface of the carbon layer. In this case, the forming of the separator may include providing a mixed material by adding a sacrificial material to the polymer material constituting the separator; Coating the mixed material on the carbon layer; And removing the sacrificial material by applying a solvent having a selective solubility with respect to the sacrificial material to form the plurality of pores.

According to another aspect of the present invention, there is provided a method of manufacturing a battery, which includes a plurality of linear negative electrode materials extending in at least two different directions to form a three-dimensional solid body having pores and being energized with each other. Providing a negative electrode having; Providing positive active materials in the pores of the negative electrode; And providing a positive electrode current collector electrically connected to the positive electrode active materials.

In some embodiments, providing the negative electrode comprises: providing conductive wires as a substrate of the linear negative electrode material; And forming a multilayer structure including a lithium metal layer and a carbon layer coating the lithium metal layer on the conductive wires.

A negative electrode foil electrode according to an embodiment of the present invention for solving the technical problem, the planar current collector for the substrate; A lithium metal layer coating the current collector; And a carbon layer coating the lithium metal layer.

In some embodiments, the cathode foil electrode may further include a separator coating the carbon layer on the carbon layer. The separator may include a plurality of pores exposing the surface of the carbon layer. The current collector may be any one of stainless steel, nickel, titanium, tantalum, copper, gold, platinum, ruthenium, silver, tin, zinc, tungsten, chromium, vanadium, molybdenum, zirconium, yttrium, antimony, and alloys thereof. Or combinations thereof.

According to an aspect of the present invention, there is provided a battery comprising: a planar negative electrode current collector for a substrate defining an internal space; A lithium metal layer coating an inner circumferential surface of the negative electrode current collector; And a lithium foil negative electrode comprising a carbon layer coating the lithium metal layer; A positive electrode including positive active materials filled in the internal space and a positive electrode current collector extending into the internal space and electrically connected to the positive active materials; And a separator for electrically separating the lithium foil negative electrode and the positive electrode.

The separator may be formed on the carbon layer of the lithium foil anode. In this case, the separator may have a plurality of pores exposing a part of the surface of the carbon layer. The planar current collector is stainless steel, nickel, titanium, tantalum, copper, gold, platinum, ruthenium, silver, tin, zinc, tungsten, chromium, vanadium, molybdenum, zirconium, yttrium, antimony, and alloys thereof It may include one or a combination thereof.

According to another aspect of the present invention, there is provided a method of manufacturing a negative electrode, including: providing a planar current collector for a substrate; Forming a multilayer structure including a lithium metal layer and a carbon layer coating the lithium metal layer on the planar current collector.

In some embodiments, the forming of the multi-layer structure may include forming the lithium metal layer by plating or reduction in solution using a lithium-containing precursor on the planar current collector for the substrate; And forming the carbon layer on the lithium metal layer. Alternatively, the forming of the multilayer structure may include forming a lithium-containing intermediate product layer using a lithium-containing precursor on the planar current collector for the substrate; Forming a carbon containing layer on the lithium containing intermediate product layer; And heating the resultant product on which the carbon-containing layer is formed, thereby simultaneously forming the lithium metal layer and the carbon layer through pyrolysis of the carbon-containing layer and a carbon reduction reaction of the lithium-containing intermediate product layer. In another embodiment, the forming of the multilayer structure may include: forming a carbon-containing layer formed on the planar current collector for the substrate; Heat treating the carbon-containing layer to form the carbon layer, and cooling to form voids between the planar current collector and the carbon layer; And forming the lithium metal layer on the cotton current collector while filling the pores by transferring lithium ions onto the planar current collector through the carbon layer by the electroplating method.

In some embodiments, the forming of the separator formed with a plurality of pores exposing the surface of the carbon layer on the carbon layer may be further performed. The forming of the separator may include providing a mixed material by adding a sacrificial material to the polymer material constituting the separator; Coating the mixed material on the carbon layer; And removing the sacrificial material by applying a solvent having a selective solubility with respect to the sacrificial material to form the plurality of pores.

According to the embodiment of the present invention, a linear negative electrode material that uses a lithium metal layer as an active material of the negative electrode material and provides a physical barrier between the lithium metal layer and the outside by a carbon layer, thereby suppressing dendritic growth of lithium. In addition, there is an advantage that the lithium source of the battery is provided on the negative electrode, and the lithium source is stabilized during battery manufacturing.

In addition, according to another embodiment of the present invention, the negative electrode assembly according to the above-described embodiment is arranged so that a plurality of linear negative electrode material having a nonwoven fabric or woven structure has a three-dimensional structure that is mechanically robust and easy to deform with pores A negative electrode assembly may be provided, which may provide a negative electrode having a negative electrode, and thus may provide a battery packaged in various shapes. In addition, the negative electrode assembly can maintain a low resistance in the entire volume of the negative electrode assembly by the conductive wire, which can drastically reduce the internal resistance of the battery as compared to using a conventional conductive material. In addition, the electrode assembly may provide a negative electrode having a long life while using lithium itself as an active material while suppressing dendritic growth of lithium by the carbon layer to secure an energy density close to the theoretical capacity of lithium.

Further, according to another embodiment of the present invention, the linear negative electrode material itself forms a conductive network throughout the negative electrode, and the conductive network serves as a negative electrode current collector, in which case the current collector may be omitted. . As a result, the thickness of the battery can be reduced by utilizing both main surfaces of the negative electrode made of linear anode materials as the cell chemistry reaction region, thereby improving the energy density of the battery. In addition, the negative electrode according to the above-described embodiment may be arranged in three dimensions such that a plurality of linear negative electrode materials have a nonwoven fabric or a woven structure, thereby providing a battery package having various shapes that are robust and easy to be deformed by their fiber characteristics. .

In addition, according to still another embodiment of the present invention, a battery having a high energy density may be easily manufactured by providing cathode active materials in a cathode formed of a plurality of linear anode materials and having pores.

According to another embodiment of the present invention, the lithium metal layer that provides a standard reduction potential as an active material of the negative electrode can be used as it is, not only to obtain a battery of high output and high capacity, but also to oxidize the uniform lithium metal layer by the carbon layer and By obtaining a reduction reaction, dendritic growth of lithium can be suppressed to improve the stability and life of the battery. In addition, the lithium source is provided to the negative electrode in the battery manufacturing, there is an advantage that the lithium is stabilized by the carbon layer during manufacturing. In addition, due to the high output and high capacity of the negative electrode, an economical battery can be provided because the same performance as that of the battery of the expensive positive electrode active material can be obtained even if a relatively low cost positive electrode active material is used.

1A is a perspective view illustrating a cross section of a linear negative electrode material according to an embodiment of the present invention, and FIG. 1B is a perspective view illustrating a cross section of a linear negative electrode material according to another embodiment of the present invention.

2A and 2B are plan and perspective views respectively illustrating structures of negative electrode assemblies using a linear negative electrode material according to various embodiments of the present disclosure.

3A is a plan view of a negative electrode assembly according to another exemplary embodiment of the present invention, and FIG. 3B is a cross-sectional view illustrating a linear negative electrode material of a negative electrode assembly taken along line III-III '.

4A is a cross-sectional view showing the structure of a battery according to an embodiment of the present invention, and FIG. 4B is a cross-sectional view showing the structure of a battery according to another embodiment of the present invention.

5A is a cross-sectional view illustrating a structure of a battery according to an embodiment of the present invention, and FIGS. 5B and 5C are partially enlarged views for explaining an electrochemical reaction layer of the battery shown in FIG. 5A.

6 is a cross-sectional view showing the structure of a battery according to another embodiment of the present invention.

7A is an exploded perspective view illustrating a laminated structure of a lithium foil negative electrode according to an exemplary embodiment of the present invention, and FIG. 7B is a perspective view illustrating a laminated structure of a lithium foil negative electrode according to another exemplary embodiment of the present invention.

8A and 8B are cross-sectional views illustrating electrode structures of batteries using negative electrodes according to various embodiments of the present disclosure, respectively.

Figure 9a is a photographic image showing the surface of the negative electrode after the charge and discharge 100 times for the battery using a negative electrode according to an embodiment of the present invention, Figure 9b is a comparative example 100 for a battery using a negative electrode without a carbon layer It is a photographic image which shows the surface of the negative electrode after performing charge / discharge.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The embodiments of the present invention are provided to more fully explain the present invention to those skilled in the art, and the following examples can be modified in various other forms, and the scope of the present invention is It is not limited to an Example. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the inventive concept to those skilled in the art.

In addition, in the following drawings, the thickness or size of each layer is exaggerated for convenience and clarity of description, the same reference numerals in the drawings refer to the same elements. As used herein, the term "and / or" includes any and all combinations of one or more of the listed items.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms "a", "an" and "the" may include the plural forms as well, unless the context clearly indicates otherwise. Also, as used herein, "comprise" and / or "comprising" specifies the presence of the mentioned shapes, numbers, steps, actions, members, elements and / or groups of these. It is not intended to exclude the presence or the addition of one or more other shapes, numbers, acts, members, elements and / or groups.

The metal fibers disclosed herein are formed by maintaining a metal or alloy in a molten state in a vessel, by quenching and solidifying the molten metal in the atmosphere through an injection hole of the vessel using a pressurization device such as a compressed gas or a piston. It can be made or produced by a condensed drawing method, and is an integral metal fiber body extending continuously with a substantially uniform thickness over substantially the entire length range.

The metal fibers have the heat resistance, plasticity, and electrical conductivity that the metal has, while at the same time having the advantages of fiber-specific weaving and nonwoven processing. The present invention relates to features and advantages of applying such metal fiber advantages to the electrode structure of a cell. However, the above-described manufacturing process is illustrative only and the present invention is not limited by this manufacturing process. By controlling the number, size, and / or emergence of the injected molten metal, the thickness, uniformity, structure such as nonwoven fabric and aspect ratio of the metal fibers can be controlled.

The term 'separation membrane' as used herein includes a separator generally used in a liquid electrolyte battery using a liquid electrolyte having a small affinity with the separator. In addition, the "separation membrane" used herein includes an intrinsic solid electrolyte membrane and / or a gel solid electrolyte membrane in which the electrolyte is strongly bound to the separation membrane, and the electrolyte and the separation membrane are recognized as the same. Therefore, the term separation membrane used herein should be interpreted to include all of them, unless it is clearly distinguished from the solid electrolyte membrane and the gel solid electrolyte membrane.

1A is a perspective view showing a cross section of a linear negative electrode material 100A according to an embodiment of the present invention, and FIG. 1B is a perspective view showing a cross section of a linear negative electrode material 100B according to another embodiment of the present invention.

Referring to FIG. 1A, a negative electrode material 100A according to an embodiment of the present invention is coated with a lithium metal layer 20 and a lithium metal layer 20 coating the conductive wire 10 based on the conductive wire 10. It includes a multi-layer structure consisting of a carbon layer (30). Since the conductive wire 10 functions as a base material of the negative electrode material 100A, the negative electrode material 100A is generally linear.

The conductive wire 10 may be a fiber body segmented to have a predetermined length. The conductive wire 10 can function as a current collector of the negative electrode to which the negative electrode material 100A is applied due to its conductivity. For example, an end of the conductive wire 10 or a portion other than the end may be electrically connected to the external lead. In some embodiments, the plurality of conductive wires 10 may be electrically connected to each other, some or all of which may be commonly connected to the external lead.

In some embodiments, conductive wire 10 may be a metal fiber. As described later, since the battery of the present invention is charged and discharged by electrodeposition and desorption of lithium, the metal fiber is preferably selected from lithium and metals that are not alloyed or dealloyed. . For example, the metal fiber may be stainless steel, nickel, titanium, tantalum, copper, gold, platinum, ruthenium, silver, tin, zinc, tungsten, chromium, vanadium, molybdenum, zirconium, yttrium, antimony, and these It may include any one or a combination of alloys of the. However, the present invention is not limited thereto, and the conductive wire 10 may include any one or a combination of conductive fibers, a composite fiber coated with a conductive layer on a non-conductive polymer, and carbon fibers. Preferably, in order to secure a wide process window in a heating process or a process using an organic solvent to form the lithium metal layer 20 to be coated on the surface of the conductive wire 10, the conductive wire 10 is heat-resistant and heat-resistant It is desirable to have chemical properties, and for this purpose, the conductive wire 10 may be a metal fiber.

The lithium metal layer 20 may be formed on the conductive wire 10 by a plating method using lithium ions dissociated in a suitable plating solution. Alternatively, a lithium-containing precursor selected from one or a combination of oxides, salts, conjugated compounds, chelates, and organic molecular compounds in a organic solvent is dissolved or dispersed to form a mixed solution, and the conductive wire 10 is immersed in the mixed solution. The lithium metal layer 20 may be provided by reducing lithium in the mixed solution on the surface of the conductive wire 10.

The lithium-containing precursor is, for example, lithium hydroxide (LiOH and LiOH H ₂ O), lithium nitride (Li ₃ N), lithium carbonate (Li ₂ CO ₃ ), lithium halide (LiF, LiCl, LiBr, LiI) , Lithium sulfide (Li ₂ S), lithium peroxide (Li ₂ O), lithium carbide (Li ₂ C ₂ ). Alternatively, the lithium-containing precursor may be an organolithium reagent.

The lithium metal layer 20 functions as an active material of the negative electrode material 100A. According to the embodiment of the present invention, since the lithium metal layer 20 is coated on the linear conductive wire 10, even if the same amount of the active material is used, it is possible to increase the capacity of the battery due to the effect of increasing the surface area due to the linear structure compared to the planar structure. Can be. In addition, since pure lithium is used as the negative electrode active material, there is an advantage that the capacity of the battery can approach the theoretical capacity and the standard reduction potential.

The carbon layer 30 coated on the lithium metal layer 20 is a diffusion path for lithium ions during charging and discharging of the battery, and the carbon layer 30 has a lithium metal layer 20 inside the outside of the negative electrode material 100A. It can function as a physical barrier to isolate from. When the battery is charged, lithium ions transferred from the anode are electrodeposited on the conductive wire 10 through the carbon layer 30, and the reduction reaction of lithium is prevented from occurring rapidly due to the carbon layer 30, which is a physical barrier, thereby conducting electricity. Lithium ions can be uniformly reduced on the wire 10 to suppress dendritic growth of lithium.

Even when the battery is discharged, the carbon layer 30 may prevent the desorption of lithium by ionization deposited on the conductive wire 10 uniformly over the entire length of the negative electrode material 100A and thereby be dusted. , Improve the discharge efficiency. As described above, the carbon layer 30 may reduce the irreversibility of the battery by inhibiting dendritic growth of the lithium as a moderator of battery chemistry that may occur during the charge and discharge of lithium, thereby improving the life of the battery.

The carbon layer 30 may be amorphous or crystalline. Preferably, it is amorphous. When the carbon layer 30 has high crystallinity, it is similar to a kind of graphite, and may react with the electrolyte at the surface. However, in the low crystalline or amorphous carbon layer, since the carbon layer 30 does not react with the electrolyte during charging and discharging, decomposition of the electrolyte is suppressed, and thus the life of the battery may be improved. In addition, the carbon layer 30 may have a mixture of SP2 graphite structure having conductivity and diamond structure of SP3 having insulation, and since the conductivity of the carbon layer 30 is not required, the SP2 may be smaller than SP3. It can have a fraction.

The thickness of the carbon layer 30 may be 1 nm to 5000 nm, which is illustrative only and the present invention is not limited thereto. If the thickness of the carbon layer 30 is less than 1 nm, the carbon layer 30 may not effectively function as a physical barrier, and the carbon layer 30 may be destroyed by stresses that may occur during charging and discharging of the battery due to the weak mechanical strength of the coating. When the thickness of the carbon layer 30 exceeds 5 μm, the physical distance of the diffusion barrier of lithium ions is increased, and the charge and discharge efficiency and the output voltage are reduced, and the lithium metal layer ( The energy density can be reduced as the volume of 20) becomes relatively small.

The carbon layer 30 may be formed using a carbon-containing precursor selected from any one or a mixture of natural graphite, synthetic graphite, soft carbon, hard carbon, coke, carbon nanotubes, exfoliated graphite, and graphene. The carbon layer 30 can be provided by dispersing the carbon-containing precursor in a polar organic solvent and forming a carbon film on the lithium metal layer 20 by hydrothermal synthesis, pyrolysis, high temperature firing, sol-k or micro synthesis. Can be.

In another embodiment, the carbon layer 30 may be provided by coating the carbon-containing polymer compound layer on the lithium metal layer 20 by a gravure method, a spray method, or the like, and thermally decomposing it to leave only the carbon on the lithium metal layer 20. have. The carbon-containing polymer compound layer is chitosan, glucose, sucrose, maltose, lactose, starch, glycogen, polystyrene (PS), polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polyacrylonitrile (PAN ), Natural or synthetic high molecular compounds such as polyethylene (PE) and polyvinylpyrrolidone (PVP). However, this is exemplary and the present invention is not limited thereto. For example, the carbon layer 30 may be directly formed on the lithium metal layer 20 by vapor deposition such as sputtering or evaporation .

Alternatively, instead of the carbon-containing polymer compound layer, a liquid organic compound may be used as a carbon source, or a liquid source may be used as an organic solution obtained by dissolving a carbon precursor as a carbon source in a solvent. The carbon precursor may be the carbon-containing natural or synthetic polymer material described above.

For example, the conductive wire 10 coated with the lithium metal layer 20 is immersed in the liquid organic compound or the organic solution, or applied to the surface by wetting the liquid organic compound on the conductive wire 10, and then heat-treated. By thermally decomposing the liquid organic compound through, the carbon layer 30 may be formed on the lithium metal layer 20. The liquid organic compound may be one or a mixture of two or more selected from the group consisting of hydrocarbon-based, alcohol-based, ether-based and ester-based compounds having 6 to 20 carbon atoms.

In some embodiments, the hydrocarbon-based compound may be any one or a mixture of hexene, nonene, dodecene, pentacene, toluene, xylene, chlorobenzoic acid, benzene, hexadecine, tetradecine and octadecine. In addition, the alcohol compound is ethyl alcohol, methyl alcohol, glycerol, propylene glycol, isopropyl alcohol, isobutyl alcohol, polyvinyl alcohol, cyclohexanol, octyl alcohol, decanol, hexatecanol, ethylene glycol, 1.2- Octanediol, 1,2-dodecanediol and 1,2-hexadecanediol, or mixtures thereof. The ether compound is octyl ether, butyl ether, hexyl ether, benzyl ether, phenyl ether, decyl ether, ethyl methyl ether, dimethyl ether, diethyl ether, diphenyl ether, tetrahydrofuran, 1,4-dioxane, polyethylene Glycol (PEG), polypropylene glycol (PPG), polytetramethylene glycol (PTMG), polyoxymethylene (POM) and polytetrahydrofuran, or mixtures thereof. In addition, the ester compound, polyethylene terephthalate, acrylate ester and cellulose acetate, isobutyl acetate, isopropyl acetate, aryl hexanoate, benzyl acetate, bonyl acetate, Butyl acetate or lactone, or mixtures thereof.

In another embodiment, after coating the intermediate product layer containing lithium using a lithium-containing precursor on the conductive wire 10, the carbon-containing polymer compound layer is coated on the intermediate product layer or the liquid organic compound or Immerse the vessel solution or use it to wet the surface of the intermediate product layer to form a carbon containing layer. Thereafter, by heating it, the carbon metal layer 30 derived from the lithium metal layer 20 and the organic solvent is simultaneously formed through thermal decomposition of the carbon-containing layer and subsequent carbon reduction reaction of the lithium-containing intermediate product layer. You may. If necessary, as described above, a separate carbon-containing monomer or a natural or synthetic polymer resin that can be dissolved in the organic solvent may be further dissolved to increase the carbon source in the organic solvent.

In another embodiment, the cathode material 100A may be formed by reversing the order of forming the carbon layer 30 and the lithium metal layer 20. For example, according to the above-described method, the carbon-containing polymer compound layer is coated on the conductive wire 10 or an organic solvent is formed to form a carbon-containing layer, and heat treated to form the carbon layer 30, and the cooling is performed. A gap may be formed between the conductive wire 10 and the carbon layer 30 by using a difference in thermal expansion coefficient between the metal wire and the carbon layer 30.

Thereafter, the lithium metal layer 20 may be formed on the conductive wire 10 while filling the pores by transferring lithium ions to the surface of the metal wire through the carbon layer 30 by electrolytic plating. According to this, there is an advantage that the lithium metal layer 20 can be safely formed in a wet manner by using lithium ions having high reactivity.

Referring to FIG. 1B, the linear negative electrode material 100B according to another embodiment may further include a separator 40 coated on the carbon layer 30. The separator 40 may be, for example, a polymer microporous membrane, a woven fabric, a nonwoven fabric, a ceramic, an intrinsic solid polymer electrolyte membrane, a gel solid polymer electrolyte membrane, or a combination thereof. The intrinsic solid polymer electrolyte membrane may include, for example, a linear polymer material or a crosslinked polymer material. The gel polymer electrolyte membrane may be, for example, a combination of any one of a plasticizer-containing polymer containing a salt, a filler-containing polymer, or a pure polymer. The solid electrolyte membrane is, for example, polyethylene, polypropylene, polyimide, polysulfone, polyurethane, polyvinyl chloride, polystyrene, polyethylene oxide, polypropylene oxide, polybutadiene, cellulose, carboxymethyl cellulose, nylon, polyacrylo Nitrile, polyvinylidene fluoride, polytetrafluoroethylene, copolymer of vinylidene fluoride and hexafluoropropylene, copolymer of vinylidene fluoride and trifluoroethylene, of vinylidene fluoride and tetrafluoroethylene In copolymers, polymethyl acrylate, polyethyl acrylate, polyethyl acrylate, polymethyl methacrylate, polyethyl methacrylate, polybutyl acrylate, polybutyl methacrylate, polyvinylacetate, and polyvinyl alcohol. Any one or a combination of these It may include a polymer matrix, additives and the electrolyte.

The materials listed with respect to the separator 40 described above are exemplary, easy to change shape, and excellent in mechanical strength, so as not to be torn or cracked by deformation of the linear negative electrode material 100B, and having any suitable electronic insulation property. A material having good ion conductivity can be selected as the material for the separator 40.

The separator 40 may be a single layer film or a multilayer film, and the multilayer film may be a laminate of the same single layer film or a stack of single layer films formed of different materials. For example, the laminate may have a structure including a ceramic coating film on the surface of a polymer electrolyte film such as polyolefin. The thickness of the separator 40 may be 5 μm to 300 μm, preferably 10 μm to 40 μm, and more preferably 10 μm to 25 μm in consideration of durability, shutdown function, and battery safety.

In some embodiments, the separator 40 may have a plurality of pores 40H exposing some surfaces of the carbon layer 30. The pores 40H may improve charge and discharge efficiency and speed of the linear anode material 100B by providing a penetration space of the electrolyte and a passage for transferring lithium ions.

In order to form the pores 40H, a sacrificial material is added to the polymer material constituting the separator 40 described above to prepare a mixed material, and the mixed material is coated on the carbon layer 30. If necessary, the linear negative electrode material coated with the mixed material may be heated or light irradiated for drying, curing, polymerization, and / or crosslinking. Thereafter, a solvent having a selective solubility with respect to the sacrificial material relative to the polymer material is applied to the linear negative electrode material coated with the mixed material (for example, the linear negative electrode material may be immersed in the solvent). By removing the sacrificial material, the pores 40H can be formed in the position occupied by the sacrificial material.

For example, as the sacrificial material, a natural resin such as wax and an organic solvent such as nucleic acid, alcohol or chloroform may be used as an optional solvent. Alternatively, the separator material may be selected from the above-mentioned water-insoluble polymer material as the separator, and methyl cellulose (MC), ethyl cellulose (EC), hydroxyethyl cellulose (HEC), and hydroxy as sacrificial materials for forming pores. Ethyl methyl cellulose (HEMC), hydroxypropyl methyl cellulose (HPMC), hydroxypropyl cellulose (HPC), hydroxypropyl methyl cellulose (HPMC), microstalin cellulose (MCC), and carboxymethyl cellulose (CMC) Or by selecting a water-soluble polymer material selected from a mixture thereof and coating the mixture on a linear negative electrode material, and then selectively removing the water-soluble polymer material using water or alcohol as a solvent, the separation membrane 40 having pores It may be formed. As another option, the pores 40H may be formed in the separator 40 using polyrefin as the sacrificial material and alkanes as the optional solvent.

The foregoing materials are exemplary and the present invention is not limited thereto. Other hydrophilic natural resins or synthetic resins, polyolefinic polymers may be used, and solvents with selective solubility in the sacrificial material need not be complete nonsolvents for the polymeric material for the membrane and do not alter the morphology of the formed mixed material. May be selected from solvents. For example, the solvent may be ethanol, propanol, butanol, butanol, pentanol, hexanol, ethylene glycol, glycerol, acetone , Dimethyl ether, diethylether, ethyl acetate, ethylacetate, dichloromethane acetone, acetone, tetrahydrofuran, tetrahydrofuran, methylene chloride, chloroform, dimethylformamide ( dimethylformamide), N-methyl-2-pyrrolidone (NMP), cyclohexane, N-methyl-pyrrolidone (NMP) and water Or a mixed solvent thereof.

2A and 2B are plan and perspective views illustrating structures of the

cathode assemblies

200A and 200B using the linear anode material 100 according to various embodiments of the present disclosure, respectively.

Referring to FIG. 2A, the negative electrode assembly 200A has a nonwoven structure in which the linear negative electrode materials 100 extend in at least different random directions. When the nonwoven fabric structure has a plurality of layers of linear anode materials 100 overlapped, a cathode structure having a three-dimensional solid structure may be provided.

The structure of the linear negative electrode materials 100 cut along the line I-I 'is, as described with reference to FIGS. 1A and 1B, the conductive wires 10, the lithium metal layer 20, the carbon layer 30, And optionally a separator 40. In the negative electrode assembly 200A having the nonwoven structure, different linear negative electrode materials 100 may have pores 100P formed to overlap each other. The electrolyte may be absorbed into the three-dimensional solid structure of the negative electrode assembly 200A through the pores 100P, and thus the lithium ions to and from the linear negative electrode material 100 may be activated.

Referring to FIG. 2B, the negative electrode assembly 200B has a woven structure in which the linear negative electrode materials 100 extend in at least different directions. However, this is exemplary and the linear cathode materials may have a mesh structure integrated with each other. The woven structure or mesh structure may be monolayered or stacked to provide a three-dimensional three-dimensional cathode structure. The linear negative electrode materials 100 may be linear

negative electrode materials

100A and 100B according to the embodiments described with reference to FIGS. 1A and 1B. In addition, similar to the cathode assembly 200B of FIG. 2A, the electrode assembly 200B may have pores 100P in a three-dimensional solid structure.

Cathode assemblies

200A and 200B according to the above-described embodiment are arranged such that the plurality of linear anode materials 100 have a nonwoven fabric, a woven fabric, or a mesh structure, thereby having mechanical pores 100P and being easily deformed. Provided is a negative electrode having a three-dimensional structure, thereby providing a battery packaged in various shapes.

The

electrode assemblies

200A and 200B can maintain low resistance in the entire volume of the negative electrode assembly by the conductive wires, which can drastically reduce the internal resistance of the battery as compared with using a conventional conductive material. In addition, the

electrode assemblies

200A and 200B may provide a negative electrode having a long lifetime while using lithium itself as an active material while suppressing dendritic growth of lithium by the carbon layer to secure an energy density close to the theoretical capacity of lithium.

By linearly arranging linear cathode materials in different directions such as nonwoven fabrics or woven structures, they can be arranged in three dimensions, providing not only pores but also linearly randomizing the reaction sites of oxidation and reduction of lithium in the three-dimensional space. Can be provided. As a result, lithium, which penetrates into the three-dimensional structure of the cathode through the pores and is electrodeposited on the surfaces of the conductive wires, cannot grow in order in any specific direction in the three-dimensional space. As a result, according to the embodiment of the present invention, dendritic growth of lithium in the negative electrode assembly can be suppressed.

Nonwoven and woven structures of the arrangement of the negative electrode assembly are exemplary, and the present invention is limited thereto. For example, it should be understood that the linear negative electrode materials 100 may have other arrangements and processability, such as lattice patterns, by blending, fiber processes such as entanglement, or mechanical processes such as mixing.

3A is a plan view of a negative electrode assembly 200C according to another embodiment of the present invention, and FIG. 3B is a cross-sectional view illustrating the linear negative electrode material 100 of the negative electrode assembly 200C taken along line III-III '.

Referring to FIGS. 3A and 3B, the linear anode materials 100 include the conductive wire 10 and the lithium metal layer 20 coated on the conductive wire 10, as described above with reference to FIG. 1B. Same as the linear anode material. However, the carbon layer 30 coated on the lithium metal layer 20 is extended and shared on other adjacent conductive wires 10. Optionally, the separator 40 may be further formed on the carbon layer 30. In this case, the separator 40 may also be shared by the plurality of linear anode materials 100.

As such, the shared carbon layer 30 forms the carbon layer 30 after forming the three-dimensional shape of the conductive wires 10 coated with the lithium metal layer 20 in the form of a nonwoven fabric or a woven structure in advance. Can be obtained. Similarly, the lithium metal layer 20 may also be commonly formed on the conductive wires so that the conductive wires 10 adjacent to each other share. To this end, the lithium metal layer 20 may be formed through a plating process or a reduction process using a lithium-containing precursor, after the conductive wires 20 have a three-dimensional shape in the form of a nonwoven fabric or a woven structure.

In another embodiment, although not shown, only the separator 40 is shared between the linear anode materials 100, and the lithium metal layer 20 and the carbon layer 30 are formed separately for each conductive wire 10. May be

4A is a cross-sectional view showing the structure of a battery 300A according to an embodiment of the present invention, and FIG. 4B is a cross-sectional view showing the structure of a battery 300B according to another embodiment of the present invention.

Referring to FIG. 4A, the battery 300A includes a negative electrode AE, a positive electrode CE, and a separator SL separating the negative electrode AE and the positive electrode CE. The cathode AE includes linear anode materials 100 forming a three-dimensional solid. The linear negative electrode materials 100 may have a three-dimensional solid structure, for example, a nonwoven structure, according to the embodiments described with reference to FIG. 2A, and FIG. 4A illustrates such a nonwoven structure. In another embodiment, the linear anode materials 100 may have a regular structure, such as a woven structure, a mixed structure of woven and nonwoven structures, or other processes that may be obtained from a fiber processing process, as described with reference to FIG. 2B. It can be formed by.

The linear negative electrode materials 100 may be a linear negative electrode material 100A according to the embodiments described with reference to FIG. 1A. The negative electrode AE may include the negative electrode current collector 150 electrically connected to the linear negative electrode materials 100, as shown in FIG. 4A. However, this is exemplary, and as described above, the conductive wires of the linear negative electrode materials 100 may be electrically connected to each other, in which case the linear negative electrode materials 100 themselves are conductive networks throughout the negative electrode EL. And the conductive network serves as a negative electrode current collector, in which case the current collector 150 may be omitted. If necessary, the linear negative electrode materials 100 may be electrically coupled to the lead LD for connection with an external terminal.

As described above, when the current collector 150 of the negative electrode AE is omitted, both main surfaces of the negative electrode made of the linear negative electrode materials 100 may be used as the battery chemical reaction region. For example, as illustrated in FIG. 4B, the separators SL_1 and SL_2 are respectively stacked on both main surfaces of the cathode AE made of the linear anode materials 100, and two anodes CE_1 are disposed thereon. , CE_2) can be laminated. When the current collector layer is omitted, the thickness of the battery 300B may be reduced by the thickness thereof, thereby improving the energy density.

Referring to FIG. 4A together with FIG. 4B, the separation membrane SL may be, for example, a polymer microporous membrane, a woven fabric, a nonwoven fabric, a ceramic, an intrinsic solid polymer electrolyte membrane, a gel solid polymer electrolyte membrane, or a combination thereof. have. The intrinsic solid polymer electrolyte membrane may include, for example, a linear polymer material or a crosslinked polymer material.

The positive electrode CE may include the positive electrode active material layer 200 and the positive electrode current collector layer 250. The positive electrode active material layer 200 may include, for example, at least one or more metals of Ni, Co, Mn, Al, Cr, Fe, Mg, Sr, V, La, and Ce, O, F, S, P, and the like. It may include a Li compound containing at least one nonmetallic element selected from the group consisting of a combination. However, this is exemplary, and according to an embodiment of the present invention, since the negative electrode has a high capacity and high efficiency, the positive electrode may be a low-cost positive electrode active material such as VO _x .

The positive electrode active material layer 200 may include active material particles having a size of about 0.01 μm to 200 μm, and may be appropriately selected according to required characteristics of a battery. In some embodiments, a conductive material may be added to the cathode active material layer 200. The conductive material may include, for example, carbon black and ultra fine graphite particles, fine carbon such as acetylene black, nano metal particle paste, or indium tin oxide (ITO) paste, which is exemplary only. However, the present invention is not limited thereto.

The positive electrode current collector layer 250 may include aluminum, titanium, stainless steel, gold, tantalum, niobium, hafnium, zirconium, vanadium, indium, cobalt, tungsten, tin, beryllium, molybdenum, or an alloy thereof. Although not shown, a lead for electrical connection with an external terminal may be coupled to the positive electrode current collector layer 250.

The cell can be activated by impregnating the electrolyte with the cell. The electrolyte may be a suitable aqueous electrolyte solution containing salts such as potassium hydroxide (KOH), potassium bromide (KBr), potassium chloride (KCL), zinc chloride (ZnCl ₂ ) and sulfuric acid (H ₂ SO ₄ ) or LiClO ₄ , LiPF ₆ It may be a non-aqueous electrolyte such as ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate containing a lithium salt such as.

Cathode CE according to the above-described embodiment has a plurality of linear cathode materials 100 are three-dimensionally arranged to have a nonwoven fabric or woven structure, yet have a pore (100P) mechanically strong, easy to deform various shapes It is possible to provide a battery package having a. In addition, while using lithium itself as an active material, the dendritic growth can be suppressed by the carbon layer and the three-dimensional arrangement, so that the standard electrode potential of lithium metal (0.0 V) can be used as an electromotive force. Can improve the battery life. In addition, since the irreversibility of the negative electrode such as excessive consumption of lithium does not appear upon reduction of lithium, the capacity of the battery can be improved as a whole by increasing the reversible capacity of the positive electrode.

In addition, compared with the conventional negative electrode assembly formed by slurry coating a negative electrode active material on the negative electrode current collector layer, according to an embodiment of the present invention, the pores in the three-dimensional solid structure of the negative electrode (CE) is a passage for the movement of lithium ions Since the mobility of lithium ions is not limited by the negative electrode itself, it can be substantially determined by the separator or the electrolyte solution. As a result, according to the embodiment of the present invention, the mobility of lithium ions can be significantly improved compared to the conventional negative electrode assembly. Accordingly, according to the embodiment of the present invention, the efficiency of charging and discharging the secondary battery can be improved.

5A is a cross-sectional view illustrating a structure of a battery 300C according to an embodiment of the present invention, and FIGS. 5B and 5C are diagrams for describing an electrochemical reaction layer EAL of the battery 300A shown in FIG. 5A. It is a partial enlarged view.

Referring to FIG. 5A, the battery 300C may have a current collector layer 250 coupled to one surface of the electrochemical reaction layer EAL and the electrochemical reaction layer EAL. The current collector layer 250 may be any current collector layer of an anode or a cathode, and is preferably an anode current collector layer.

The battery 300C has an electrode configuration in which the negative electrode and the positive electrode are mixed in the electrochemical reaction layer (EAL). The electrochemical reaction layer EAL includes a cathode AE including linear anode materials 100 and cathode active materials 200 inserted into pores 100P of the cathode AE. The linear negative electrode materials 100 may be a linear negative electrode material 100B coated with a separator as described with reference to FIG. 1B. Electrical separation between the linear anode material 100 and the cathode active materials 200 may be achieved by a separator.

The positive electrode active materials 200 may have any structure suitable to be inserted into the pores 100P, and may have a particle shape as shown in FIG. 5B. An electrolytic solution is impregnated in the electrochemical reaction layer EAL, and as a result, lithium transport may be activated between the positive electrode active materials 200 and the linear negative electrode material 100.

In some embodiments, a conductive material may be further added to improve electrical conductivity between the cathode active materials 200. The conductive material may be a particulate conductive material 210a as shown in FIG. 5B. The particulate conductive material 210a may be carbon black, ultrafine graphite particles, fine carbon such as acetylene black, nano metal particle paste, or indium tin oxide (ITO) paste.

In another embodiment, the conductive material may be a linear conductive material 210b as shown in FIG. 5C. In addition, a particulate conductive material 210a as shown in FIG. 5B may be applied together with the linear conductive material 210b. The linear conductive material 210b may be, for example, a metal wire or a conductive polymer wire, but the present invention is not limited thereto. For example, a positive electrode active material in which a conductive wire and a particulate conductive material are integrally combined may be used.

In addition, suitable binders may be added in the electrochemical reaction layer (EAL) to ensure mechanical bonding in the electrochemical reaction layer (EAL). In some embodiments, after the linear negative electrode material 100 and the positive electrode active materials 200 are mixed to reduce the volume of the electrochemical layer (EAL), pressure fixing may be performed, in which case thermal energy may be applied. It may be.

The linear anode materials 100 may be electrically connected to each other prior to forming a carbon layer or a separator to provide a current collector structure by a three-dimensional conductive network, and form a cathode by coupling a lead to the current collector structure. can do. The positive electrode active materials 200 may be electrically coupled by the current collector 250.

According to the embodiment of the present invention, by using the lithium metal layer itself as a negative electrode active material can not only obtain an electromotive force close to the theoretical value, the positive electrode and the negative electrode is mixed in the electrochemical reaction layer, the distance between the positive electrode and the negative electrode is closer The internal resistance of the battery can be reduced, and the speed and efficiency of charging and discharging can be improved. In addition, by increasing the efficiency of the negative electrode, an economical battery having the same effect can be provided even when a relatively low cost positive electrode material such as VO _x is used for the positive electrode.

6 is a cross-sectional view showing the structure of a battery 300D according to another embodiment of the present invention.

Referring to FIG. 6, the battery 300D has an electrode configuration in which a negative electrode and a positive electrode are mixed in a single electrochemical reaction layer EAL, similar to the battery 300C of FIG. 5A. The current collecting layer 250 may be coupled to any one of the positive electrode and the negative electrode, preferably the positive electrode. When the current collector layer 250 is connected to the positive electrode, the linear negative electrode materials 100 may be provided with a negative electrode lead for connection with an external terminal.

The current collector layer 250 may be formed to three-dimensionally surround the electrochemical reaction layer EAL, instead of being stacked in one plane on one main surface of the electrochemical reaction layer EAL. The current collector layer 250 may be a conductive polymer film, a metal layer, or a composite layer in which they are stacked. According to the exemplary embodiment of the present invention, not only the internal resistance of the battery 300D is reduced due to the increase of the area due to the expanded current collector layer 250, but also the energy density is increased, and the charge / discharge reaction of the battery has a three-dimensional structure. By rising in all areas, the charge and discharge speed and efficiency are improved, and a high output battery can be provided.

The battery structure according to the various embodiments described above may be deformed in three dimensions such as stacking, bending, and winding due to the excellent processability and flexibility due to the fibrous properties of the negative electrode assembly. It is possible to provide a flexible battery which can be attached to the same known structure or directly to surfaces such as garments, bags and flexible displays. In addition, the negative electrode assembly according to the embodiment of the present invention substantially suppresses dendritic growth of lithium, thereby improving the irreversibility of charging and discharging, and obtaining an output voltage close to a theoretical value due to the reduction potential of lithium, thereby providing high output, high capacity, Since a high efficiency and long life battery can be obtained, it can be applied as a medium to large battery for power source or electric power storage of automobile.

Referring to FIG. 7A, a lithium foil negative electrode 700A according to an embodiment of the present invention uses a planar current collector 710 as a substrate. The planar current collector 710 is made of a metal, for example, stainless steel, nickel, titanium, tantalum, copper, gold, platinum, ruthenium, silver, tin, zinc, tungsten, chromium, vanadium, molybdenum, zirconium, or yttrium. , Antimony, and alloys thereof, or any combination thereof. However, this is exemplary, and the planar current collector 710 may be another conductive metal or conductive polymer capable of covering the lithium metal layer 720 as a substrate.

On the planar current collector 710, a negative electrode active material layer having a multilayer structure including a lithium metal layer 720 and a carbon layer 730 coating the lithium metal layer 720 is formed. The lithium metal layer 720 may have a thickness of several tens of nm to several tens of micrometers of the lithium metal layer 720. The lithium ions dissociated in the plating solution may be formed by depositing on the planar current collector 710 by the plating method.

In another embodiment, a mixed solution is formed by dissolving or dispersing a lithium-containing precursor selected from any one or a combination of oxides, salts, conjugated compounds, chelates, and organic molecular compounds of lithium in an organic solvent to form a planar current collector 710 ) May be provided in the mixed solution by reducing the lithium on the surface of the planar current collector 710. Since the said lithium containing precursor is the same as the lithium containing precursor mentioned above with reference to FIG. 1A, description is abbreviate | omitted.

The carbon layer 730 coated on the lithium metal layer 720 is a diffusion path for lithium ions during charging and discharging of the battery, and the carbon layer 730 connects the inner lithium metal layer 720 to the outside of the cathode 700A. Can serve as a physical barrier to isolate. When the battery is charged, lithium ions transferred from the positive electrode are deposited on the planar current collector 710 through the carbon layer 730, and the reduction reaction of lithium is prevented from occurring rapidly by the carbon layer 730 which is a physical barrier. Lithium ions can be uniformly reduced on the planar current collector 710 to suppress dendritic growth of lithium.

Even when the battery is discharged, the carbon layer 730 prevents desorption of lithium by ionization deposited on the planar current collector 710 evenly over the entire area of the negative electrode 700A and prevents dusting. Suppresses irreversibility. As described above, the carbon layer 730 may reduce dendritic growth of lithium as a moderator of battery chemistry that may occur during charging and discharging of lithium to improve battery life.

The carbon layer 730 may be amorphous or crystalline. Preferably, it is amorphous. When the carbon layer 730 has high crystallinity, it is similar to a kind of graphite and may react with the electrolyte at the surface. However, in the low crystalline or amorphous carbon layer, the carbon layer 730 does not react with the electrolyte during charging and discharging, and thus decomposition of the electrolyte is suppressed, thereby improving the life of the battery. In addition, the carbon layer 730 may have a mixture of SP2 graphite structure having conductivity and diamond structure of SP3 having insulation, and since the conductivity of the carbon layer 730 is not required, the SP2 is smaller than SP3. It can have a fraction.

The thickness of the carbon layer 730 may be 1 nm to 5000 nm. If the thickness of the carbon layer 730 is less than 1 nm, the carbon layer 730 may not effectively function as a physical barrier, and due to the weak mechanical strength of the coating, the carbon layer 730 may be destroyed by stresses that may occur during charging and discharging of the battery. When the thickness of the carbon layer 730 exceeds 5000 nm, the physical distance of the diffusion barrier of lithium ions is increased, so that the charge and discharge efficiency and the output voltage are reduced, and the lithium metal layer ( The energy density can be reduced as the volume of 720 is relatively small.

The carbon layer 730 may be formed using a carbon-containing precursor selected from any one or a mixture of natural graphite, synthetic graphite, soft carbon, hard carbon, coke, carbon nanotubes, exfoliated graphite, and graphene. The carbon layer 730 may be provided by dispersing a suitable carbon-containing precursor in a polar organic solvent and forming a carbon film on the lithium metal layer 720 by hydrothermal synthesis, pyrolysis, high temperature firing, sol-stacking or microsynthesis. Can be.

In another embodiment, the carbon layer 730 may be provided by coating a carbon-containing polymer compound layer on the lithium metal layer 720 by a gravure method, a spray method, or the like, and thermally decomposing it to leave only the carbon on the lithium metal layer 720. have. Since the carbon-containing polymer compound layer may be a natural or synthetic polymer compound of the kind described above with reference to FIG. 1A, description thereof will be omitted. However, this is exemplary and the present invention is not limited thereto. For example, the carbon layer 730 may be directly formed on the lithium metal layer 720 by vapor deposition such as sputtering or evaporation .

For example, the surface current collector 710 coated with the lithium metal layer 720 is immersed in the liquid organic compound, or applied to the surface by wetting the liquid organic compound in the surface current collector 710, and then pyrolysis. By using, the carbon layer 730 may be formed on the lithium metal layer 720. The liquid organic compound may be one or a mixture of two or more selected from the group consisting of hydrocarbon-based, alcohol-based, ether-based and ester-based compounds having 6 to 20 carbon atoms. In some embodiments, the hydrocarbon-based compound, the alcohol-based compound, the ether-based compound, and the ester-based compound may be a compound of the kind described above with reference to FIG. 1A, and thus description thereof is omitted.

In another embodiment, after coating the intermediate product layer containing lithium using a lithium-containing precursor on the planar current collector 710, the carbon-containing polymer compound layer is coated on the intermediate product layer or the liquid organic compound described above Or immersed in the organic solution or wetted the surface of the intermediate product layer to form a carbon-containing layer. Subsequently, heating is performed to simultaneously form a lithium metal layer 720 and a carbon layer 730 derived from the organic solvent through thermal decomposition of the carbon-containing layer and subsequent carbon reduction reaction of the lithium-containing intermediate product layer. You may. If necessary, as described above, a separate carbon-containing monomer or a natural or synthetic polymer resin that can be dissolved in the organic solvent may be further dissolved to increase the carbon source in the organic solvent.

In another embodiment, the cathode 700A may be formed by reversing the order of forming the carbon layer 730 and the lithium metal layer 720. For example, according to the above-described method, the carbon-containing polymer compound layer is coated on the planar current collector 710 or an organic solvent is formed to form a carbon-containing layer, and heat-treated to form the carbon layer 730, and upon cooling A gap may be formed between the planar current collector 710 and the carbon layer 730 by using a difference in thermal expansion coefficient between the planar current collector 710 and the carbon layer 730.

Subsequently, the lithium metal layer 720 may be formed on the planar current collector 710 while the lithium ions are transferred to the surface of the planar current collector 710 through the carbon layer 730 to fill the pores. . According to this, there is an advantage that the lithium metal layer 720 can be safely formed in a wet manner by using lithium ions having high reactivity.

Referring to FIG. 7B, the cathode 700B according to another embodiment may further include a separator 740 coated on the carbon layer 730. The separation membrane 740 may be, for example, a polymer microporous membrane, a woven fabric, a nonwoven fabric, a ceramic, an intrinsic solid polymer electrolyte membrane, a gel polymer electrolyte membrane, a solid electrolyte membrane, or a combination thereof. Since the type of the intrinsic solid polymer electrolyte membrane, the gel polymer electrolyte membrane, and the solid electrolyte membrane are the same as described above with reference to FIG. 1B, a detailed description thereof will be omitted.

The materials listed with respect to the separator 740 described above are exemplary, easy to change shape, and excellent in mechanical strength so that they do not tear or crack under deformation of the electrode 700B, and have any suitable electronic insulation and excellent ions. A material having conductivity may be selected as the material for the separator 740.

The separator 740 may be a single layer film or a multilayer film, and the multilayer film may be a laminate of the same single layer film or a stack of single layer films formed of different materials. For example, the laminate may have a structure including a ceramic coating film on the surface of a polymer electrolyte film such as polyolefin. The thickness of the separator 740 may be 5 μm to 300 μm, preferably 10 μm to 40 μm, and more preferably 10 μm to 25 μm in consideration of durability, shutdown function, and battery safety.

In some embodiments, the separator 70 may have a plurality of pores 740H exposing some surfaces of the carbon layer 730. The pores 740H may improve charge and discharge efficiency and speed of the cathode 700B by providing a penetration space of the electrolyte and a passage for transferring lithium ions.

In order to form the pores 740H, a sacrificial material is added to the polymer material constituting the separator 740 described above to prepare a mixed material, and the mixed material is coated on the carbon layer 730. If necessary, the cathode 700B coated with the mixed material may be heated or irradiated with light for drying, curing, polymerization, and / or crosslinking. Thereafter, a solvent having selective solubility with respect to the sacrificial material relative to the polymer material is applied to the negative electrode 700B coated with the mixed material (for example, the negative electrode 700B may be immersed in the solvent). By removing the sacrificial material, pores 740H may be formed at positions occupied by the sacrificial material.

For example, as the sacrificial material, a natural resin such as wax and an organic solvent such as nucleic acid, alcohol or chloroform may be used as an optional solvent. Alternatively, the separator material is a water-soluble polymer selected from the water-insoluble polymer material described above as a separator, and selected from one or a mixture of the above-described water-soluble polymer material materials with reference to Figure 1b as a sacrificial material for forming a pore. After selecting a material and coating a mixture thereof on the linear negative electrode material, the water-soluble polymer material may be selectively removed using water or alcohol as a solvent, thereby forming a separator 740 having pores. As another option, the pores 740H may be formed in the separator 740 using polyolefins as the sacrificial material and alkanes as the optional solvent.

The foregoing materials are exemplary and the present invention is not limited thereto. Other hydrophilic natural resins or synthetic resins, polyolefinic polymers may be used, and solvents with selective solubility in the sacrificial material need not be complete nonsolvents for the polymeric material for the membrane and do not alter the morphology of the formed mixed material. May be selected from solvents. An example of the solvent is the same as the example described above with reference to FIG.

8A and 8B are cross-sectional views illustrating electrode structures of the

batteries

900A and 900B using the negative electrode 700 according to various embodiments of the present disclosure, respectively. Of the components shown, components having the same reference numerals as those of the components shown in FIGS. 7A and 7B may refer to the foregoing disclosure unless otherwise contradicted.

Referring to FIG. 8A, the cathode 700 includes a planar current collector 710, a lithium metal layer 720, a carbon layer 730, and a separator 740 for a substrate. The positive electrode 800 includes a positive electrode active material layer 850 and a positive electrode current collector 860.

The positive electrode active material layer 850 is a group consisting of at least one or more metals of Ni, Co, Mn, Al, Cr, Fe, Mg, Sr, V, La, and Ce, and O, F, S, P, and combinations thereof. Li may include at least one non-metal element selected from (850a). For example, Li compound 850a has Li _a A _1-b B _b D ₂ , wherein A is selected from Ni, Co, Mn, and combinations thereof, and B Is selected from the group consisting of Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, rare earth elements, and combinations thereof, and D is O, F, S, P, and combinations thereof And 0.95 ≦ a ≦ 1.1, and 0 ≦ b ≦ 0.5. However, this is exemplary and the present invention is not limited thereto. According to the embodiment of the present invention, since the negative electrode has a high capacity and high efficiency, the positive electrode may be a low-cost positive electrode active material such as VO ₂ .

The positive electrode active material 850a may be particles having a size of about 0.01 μm to 200 μm. Preferably, the positive electrode active material 850a may have a size of about 0.1 μm to 15 μm. However, this is merely exemplary and may be appropriately selected depending on the required characteristics of the battery. In some embodiments, the cathode active material layer 850 may further include a conductive material 850b. The conductive material may be, for example, carbon black and ultra fine graphite particles, fine carbon such as acetylene black, nano metal particle paste, or indium tin oxide (ITO) paste. The positive electrode active material layer 850 described above may be coated on the negative electrode 700 in a slurry form as is well known in the art, but the present invention is not limited thereto. In addition, if necessary, a binder for mechanical fixing of the positive electrode active material may be further provided in the positive electrode active material layer 850.

The current collector 860 for the positive electrode is provided on the positive electrode active material layer 850. In the electrode structure according to the present embodiment, due to the current collector 710 having an area substantially equal to or larger than that of the lithium metal layer, the internal resistance of the battery is drastically reduced by maintaining low resistance over the entire volume in the negative electrode. Charge and discharge efficiency and electromotive force to be close to the theoretical value.

Referring to FIG. 8B, the planar current collector 710 of the negative electrode 700 defines an internal space in which the positive electrode active material layer 850 is to be filled. To this end, the planar current collector 710 may be bent as shown. Although FIG. 8B illustrates that the planar current collector 710 is composed of a plurality of bent planes, this is exemplary, and the planar current collector 710 may have a curved surface or may have a polygonal plane.

As such, the lithium metal layer 720 and the carbon layer 730 are sequentially coated on the inner circumferential surface of the planar current collector 710 having a three-dimensional structure forming an internal space. In order to separate the cathode active material layer 850 and the cathode in the inner space, a separator 740 may be provided therebetween. The positive electrode current collector 860 extends into the inner space and is electrically connected to the positive electrode active material layer 850.

Through the positive electrode active material layer 850, a suitable aqueous electrolyte solution containing salts such as potassium hydroxide (KOH), potassium bromide (KBr), potassium chloride (KCL), zinc chloride (ZnCl ₂ ), and sulfuric acid (H ₂ SO ₄ ), or The

batteries

900A and 900B can be activated by impregnating non-aqueous electrolytes such as ethylene carbonate, propylene carbonate, dimethyl carbonate, and diethyl carbonate containing lithium salts such as LiClO ₄ and LiPF ₆ .

According to the embodiment of the present invention, using the lithium metal layer itself as a negative electrode active material, the internal resistance of the negative electrode is significantly reduced, not only can obtain an electromotive force close to the theoretical value of the lithium battery, but also the speed and efficiency of charge and discharge Can be improved. In addition, by increasing the efficiency of the negative electrode, an economical battery having the same effect can be provided even when a relatively low cost positive electrode material such as VO _x is used for the positive electrode.

9A, in the negative electrode 700 of the battery according to the exemplary embodiment of the present invention, no dendritic structure of lithium or dust of lithium is observed on the surface thereof. However, referring to FIG. 9B, in the negative electrode 700R of the battery of the comparative example, dust was observed due to sudden and uneven release of lithium during dendritic growth and discharge of lithium at the portion indicated by the dotted line A. FIG.

According to the negative electrode according to the embodiments of the present invention, the dendritic growth of lithium is substantially suppressed to obtain an output voltage due to the reduction potential of lithium, as well as to improve the irreversibility of charge and discharge, resulting in high output, high capacity and high efficiency. And since a long life battery can be obtained, it can be applied as a medium-large battery for power source or electric power storage of a motor vehicle.

The present invention described above is not limited to the above-described embodiments and the accompanying drawings, and various substitutions, modifications, and alterations are possible within the scope without departing from the technical spirit of the present invention, which are common in the art. It will be apparent to those who have knowledge.

Claims

Conductive wires;

A lithium metal layer coating the conductive wire; And

Linear anode material comprising a carbon layer coating the lithium metal layer.
The method of claim 1,

Linear anode material further comprising a separator coating the carbon layer on the carbon layer.
The method of claim 1,

The separator includes a plurality of pores for exposing the surface of the carbon layer.
The method of claim 1,

And the conductive wires are metal fibers.
The method of claim 1,

The conductive wires may include any one or a combination of conductive fibers, a composite fiber coated with a conductive layer on a non-conductive polymer, and carbon fibers.
Conductive wires extending in at least two different directions to form three-dimensional solids having pores;

A lithium metal layer coating the conductive wire; And

A negative electrode assembly comprising a carbon layer coating the lithium metal layer.
The method of claim 6,

The anode assembly further comprises a separator for coating the carbon layer.
The method of claim 6,

And the lithium metal layer is formed to extend over adjacent different conductive wires.
The method of claim 6,

And the carbon layer is formed to extend onto a lithium metal layer on adjacent different conductive wires.
The method of claim 7, wherein

The separator is characterized in that the negative electrode assembly is formed to extend on the carbon layer on the adjacent different conductive wires.
The method of claim 6,

And the conductive wire comprises a metal fiber.
The method of claim 6,

The conductive wires may include any one or a combination of conductive fibers, a composite fiber coated with a conductive layer on a non-conductive polymer, and carbon fibers.
The method of claim 6,

And the conductive wires have a nonwoven structure, a woven or a mesh structure.
A negative electrode having a plurality of linear negative electrode materials extending in at least two different directions to form a three-dimensional solid body having pores and energizing each other;

A positive electrode including positive electrode active materials inserted into the pores of the negative electrode and a positive electrode current collector electrically connected to the positive electrode active materials; And

A separator separating the cathode and the anode,

The cathode includes conductive wires forming the three-dimensional solid;

A lithium metal layer coating the conductive wire; And

A secondary battery comprising a carbon layer coating the lithium metal layer.
The method of claim 14,

The positive electrode current collector is a secondary battery comprising a conductive wire for the positive electrode extending into the pores of the three-dimensional solid.
The method of claim 14,

The positive electrode current collector, the secondary battery comprising a conductive foil surrounding at least a portion of the three-dimensional solid surface.
Providing conductive wires; And

Forming a multilayer structure including a lithium metal layer and a carbon layer coating the lithium metal layer on the conductive wires,

Forming the multilayer structure,

Forming the lithium metal layer by plating or reduction in solution using a lithium-containing precursor; And

And forming the carbon layer on the lithium metal layer.
The method of claim 17, wherein the forming of the multilayer structure comprises:

Forming a lithium-containing intermediate product layer on the conductive wire by using a lithium-containing precursor;

Forming a carbon containing layer on the lithium containing intermediate product layer; And

Heating the resultant product on which the carbon-containing layer is formed, thereby simultaneously forming the lithium metal layer and the carbon layer through thermal decomposition of the carbon-containing layer and a carbon reduction reaction of the lithium-containing intermediate product layer.
The method of claim 17, wherein the forming of the multilayer structure comprises:

Forming a carbon containing layer on the conductive wire;

Heat treating the carbon-containing layer to form the carbon layer, and cooling to form voids between the conductive wire and the carbon layer; And

And forming the lithium metal layer on the conductive wire while filling the pores by transferring lithium ions onto the conductive wire through the carbon layer by an electroplating method.
The method of claim 17, wherein providing the conductive wire comprises:

And providing a plurality of conductive wires and arranging them to form a three-dimensional solid structure.
Planar current collectors for base materials;

A lithium metal layer coating the current collector; And

Lithium foil anode comprising a carbon layer coating the lithium metal layer.
The method of claim 21,

Lithium foil anode further comprises a separator for coating the carbon layer on the carbon layer.
The method of claim 22,

The separator includes a plurality of pores for exposing the surface of the carbon layer.
Providing a planar current collector for the substrate;

Forming a multi-layer structure comprising a lithium metal layer and a carbon layer coating the lithium metal layer on the planar current collector.
The method of claim 24, wherein the forming of the multilayer structure comprises:

Forming the lithium metal layer on the planar current collector for the substrate by a plating method or an in-solution reduction method using a lithium-containing precursor; And

And forming the carbon layer on the lithium metal layer.
The method of claim 24, wherein the forming of the multilayer structure comprises:

Forming a lithium-containing intermediate product layer using a lithium-containing precursor on the planar current collector for the substrate;

Forming a carbon containing layer on the lithium containing intermediate product layer; And

Heating the resultant product on which the carbon-containing layer is formed, and simultaneously forming the lithium metal layer and the carbon layer through thermal decomposition of the carbon-containing layer and a carbon reduction reaction of the lithium-containing intermediate product layer.
The method of claim 24, wherein the forming of the multilayer structure comprises:

Forming a carbon-containing layer formed on the planar current collector for the substrate;

Heat treating the carbon-containing layer to form the carbon layer, and cooling to form voids between the planar current collector and the carbon layer; And

And forming the lithium metal layer on the surface current collector while transferring the lithium ions through the carbon layer onto the planar current collector by the electroplating method to fill the voids.
The method of claim 24,

And forming a separator having a plurality of pores exposing the surface of the carbon layer on the carbon layer.
The method of claim 28, wherein forming the separator,

Adding a sacrificial material to the polymer material constituting the separator to provide a mixed material;

Coating the mixed material on the carbon layer; And

And removing the sacrificial material to form the plurality of pores by applying a solvent having a selective solubility with respect to the sacrificial material.
A planar negative electrode current collector for a substrate defining an internal space; A lithium metal layer coating an inner circumferential surface of the negative electrode current collector; And a lithium foil negative electrode comprising a carbon layer coating the lithium metal layer;

A positive electrode including positive active materials filled in the internal space and a positive electrode current collector extending into the internal space and electrically connected to the positive active materials; And

And a separator for electrically separating the lithium foil negative electrode and the positive electrode.
The method of claim 30,

The separator is formed on the carbon layer.
The method of claim 30,

And the separator has a plurality of pores exposing a portion of the surface of the carbon layer.
The method of claim 30,

The planar current collector is any one of stainless steel, nickel, titanium, tantalum, copper, gold, platinum, ruthenium, silver, tin, zinc, tungsten, chromium, vanadium, molybdenum, zirconium, yttrium, antimony and alloys thereof Or a combination thereof.