KR101503571B1 - Anode material, electrode assembly, rechargeable battery and method of fabricating them - Google Patents

Abstract

Embodiments of the present invention relate to an anode material, a cathode assembly, a secondary battery, and a method of manufacturing the same. An anode material according to an embodiment of the present invention includes a conductive wire; A lithium metal layer coating the conductive wire; And a carbon layer coating the lithium metal layer.

Description

[0001] The present invention relates to an anode material, an electrode assembly, a rechargeable battery and a method of fabricating them,

The present invention relates to secondary battery technology, and more particularly, to an anode material, a cathode assembly, a secondary battery, and a manufacturing method thereof.

Recently, the demand for secondary batteries such as lithium batteries, lithium ion batteries, and lithium ion polymer batteries is greatly increasing. The secondary battery is a battery that can be charged and discharged using an electrode material having excellent reversibility. The secondary battery may be a Ni-MH battery, a Li battery, a Li-ion battery, or the like depending on the anode and the anode active material. . Such secondary batteries are increasingly being applied as power sources for IT devices such as smart phones, portable computers, and electronic paper, or mobile means such as bicycles and electric vehicles.

When lithium is used as the negative electrode active material, the standard electrode potential of the lithium metal can be used as it is as an electromotive force, so that a high output cell can be obtained and the capacity of the battery can be brought close to the theoretical capacity, thereby maximizing the energy density. However, in the case of a lithium active material, there is a problem that lithium dendrites, which are crystalline protrusions, grow on the cathode due to chemical reaction by charging and discharging of the battery. When the dendritic lithium is excessively grown, the dendritic lithium passes through the separator and the positive electrode and the negative electrode of the battery are separated from each other. The cathode can be short-circuited.

Due to the problems of the lithium active material, carbonaceous materials having excellent cycle characteristics and having a theoretical capacity of 372 mAh / g have been widely commercialized as negative electrode active materials for secondary batteries. However, as the application of the secondary battery extends not only to small electric power but also to the medium power and high electric power fields, it is increasingly required to increase the capacity and output of the secondary battery. Accordingly, lithium having a theoretical capacity 8 times higher than that of the carbon- Is required as a negative electrode active material.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide an anode material having high capacity and high output while having reliability and improved lifetime by using lithium itself as an anode active material.

Another object of the present invention is to provide a cathode assembly having the above-described advantages.

It is another object of the present invention to provide a secondary battery having a high energy density and a high energy density while having the above-described advantages.

Another object of the present invention is to provide a cathode assembly and a manufacturing method capable of forming the cathode assembly and the battery in large quantities economically and promptly.

According to an aspect of the present invention, there is provided an anode material comprising: a conductive wire; A lithium metal layer coating the conductive wire; And a carbon layer coating the lithium metal layer. The linear cathode material may further include a separation layer coating the carbon layer on the carbon layer.

The separator may include a plurality of pores exposing a surface of the carbon layer. The conductive wires may comprise metal fibers. The metal fibers may include any one or combination of stainless steel, nickel, titanium, tantalum, copper, gold, platinum, ruthenium, silver, and alloys thereof. In another embodiment, the conductive wires may comprise a conductive polymer, a composite fiber body coated with a conductive layer on a non-conductive polymer, and / or a combination of carbon fibers.

According to another aspect of the present invention, there is provided a negative electrode assembly comprising: 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 a carbon layer coating the lithium metal layer. The cathode assembly may further include a separator coating the carbon layer. The separation membrane may include a plurality of pores exposing a surface of the carbon layer.

The lithium metal layer may be formed to extend over adjacent conductive wires. Also, the carbon layer may be formed to extend on adjacent conductive wires. Similarly, the separation membrane may be formed to extend onto the carbon layer on adjacent conductive wires. The conductive wires may have a nonwoven structure. Alternatively, the conductive wires may have a woven structure.

According to another aspect of the present invention, there is provided a rechargeable battery including a plurality of linear cathode materials having a plurality of linear anode materials formed in at least two different directions to form three- ; A positive electrode comprising positive electrode active materials inserted into the pores of the negative electrode and a positive electrode 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 body; A lithium metal layer coating the conductive wire; And a carbon layer coating the lithium metal layer. In addition, the separation layer may be formed to coat the carbon layer of the cathode.

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

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

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

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

In some embodiments, the step of forming the separation layer may be performed by forming a plurality of pores on the carbon layer exposing the surface of the carbon layer. In this case, the step of forming the separation membrane may include the steps of: providing a mixed material by adding a sacrificial material to the polymer material constituting the separation membrane; Coating the mixed material on the carbon layer; And applying a solvent having an optional solubility to the sacrificial material to remove 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, the method comprising: forming a plurality of linear cathode materials, each of which extends in at least two different directions to form a three- Providing a cathode having an anode; Providing cathode active materials in the pores of the cathode; And a cathode current collector electrically connected to the cathode active materials.

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

According to the embodiment of the present invention, a linear negative electrode material can be provided which 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 the carbon layer, thereby suppressing dendrites growth of lithium.

In addition, according to another embodiment of the present invention, the cathode assemblies according to the above-described embodiments have a structure in which a plurality of linear anode materials are arranged so as to have a nonwoven fabric or a woven structure, A negative electrode assembly can be provided which can provide a negative electrode having a negative electrode, and thus a battery packaged in various shapes. In addition, the cathode assembly can maintain a low resistance within the entire volume of the cathode assembly by the conductive wire, so that the internal resistance of the battery can be drastically reduced as compared with the use of a conventional conductive material. In addition, the electrode assembly can provide a negative electrode having a long life while ensuring an energy density close to the theoretical capacity of lithium while suppressing the resin phase growth of lithium by the carbon layer while using lithium itself as an active material.

According to another embodiment of the present invention, the linear negative electrode materials themselves form a conductive network over the entire cathode, and the conductive network serves as a negative electrode collector. In this case, the collector may be omitted . As a result, it is possible to reduce the thickness of the battery by utilizing both of the both surfaces of the negative electrode made of the linear negative electrode materials as the battery chemical reaction region, thereby improving the energy density of the battery. In addition, the negative electrode according to the above-described embodiment can provide a battery package having a plurality of linear negative electrodes arranged in a three-dimensional manner so as to have a nonwoven fabric or a woven structure, and being robust and easy to deform due to their fiber properties, .

According to another embodiment of the present invention, a battery having a high energy density can be easily manufactured by providing cathode active materials in a cathode having pores formed of a plurality of linear anode materials.

FIG. 1A is a perspective view showing a cross section of a linear negative electrode material 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 according to another embodiment of the present invention.
2A and 2B are a plan view and a perspective view, respectively, illustrating the structure of cathode assemblies using a linear anode material according to various embodiments of the present invention.
FIG. 3A is a plan view of a cathode assembly according to another embodiment of the present invention, and FIG. 3B is a cross-sectional view illustrating a linear cathode material of a cathode assembly taken along a line III-III '.
FIG. 4A is a cross-sectional view illustrating a structure of a battery according to an embodiment of the present invention, and FIG. 4B is a cross-sectional view illustrating a structure of a battery according to another embodiment of the present invention.
FIG. 5A is a cross-sectional view showing the structure of a battery according to an embodiment of the present invention, and FIGS. 5B and 5C are 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.

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

The embodiments of the present invention are described in order to more fully explain the present invention to those skilled in the art, and the following embodiments may be modified into various other forms, The present invention is not limited to the embodiment. Rather, these embodiments are provided so that this disclosure will be more faithful and complete, and will fully convey the scope of the invention to those skilled in the art.

In the following drawings, thickness and size of each layer are exaggerated for convenience and clarity of description, and the same reference numerals denote the same elements in the drawings. 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" include singular forms unless the context clearly dictates otherwise. Also, " comprise "and / or" comprising "when used herein should be interpreted as specifying the presence of stated shapes, numbers, steps, operations, elements, elements, and / And does not preclude the presence or addition of one or more other features, integers, operations, elements, elements, and / or groups.

The metal fibers disclosed in this specification can be produced by maintaining the metal or alloy in a molten state in a container and spraying the melt into the atmosphere through the injection hole of the container by using a pressurizing device such as a compressed gas or a piston to quench and solidify And can be produced by a bundle drawing method, and is a substantially continuous metal fiber body having a substantially uniform thickness in its entire length range.

The metal fibers have heat resistance, plasticity and electrical conductivity, and have the advantage of being capable of woven fabrics and nonwoven fabrication processes unique to the fibers. The present invention relates to features and advantages of applying the advantages of such metal fibers to an electrode structure of a battery. However, the above-described manufacturing process is only illustrative and the present invention is not limited by such a manufacturing process. By controlling the number and size of the injection holes and / or the emergence of the molten metal injected, the thickness, uniformity of the metal fibers, the nonwoven fabric-like texture, and the aspect ratio thereof can be controlled.

As used herein, the term " separator " includes a separator commonly used in a liquid electrolyte cell using a liquid electrolyte having a low affinity for the separator. Also, the 'separator' used in the present specification includes an intrinsic solid electrolyte membrane and / or a gel solid electrolyte membrane in which the electrolyte is strongly bound to the separator, and the electrolyte and the separator are recognized as being identical. Therefore, the term separation membrane used in this specification should be construed to include all of them unless clearly distinguished from the solid electrolyte membrane and the gel solid electrolyte membrane.

FIG. 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.

1A, an anode material 100A according to an embodiment of the present invention includes a lithium metal layer 20 and a lithium metal layer 20 coating a conductive wire 10 with a conductive wire 10 as a base material Layer structure composed of a carbon layer 30 that is formed on the substrate. Since the conductive wire 10 functions as a base material of the anode material 100A, the anode material 100A is entirely linear.

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

In some embodiments, the conductive wire 10 may be a metal fiber. As will be described later, since the battery of the present invention is charged and discharged by electrodeposition and desorption of lithium, it is preferable that the metal fiber is selected from lithium and alloying and non-alloying metals. For example, the metal fibers may include any one or combination of stainless steel, nickel, titanium, tantalum, copper, gold, platinum, ruthenium, silver and alloys thereof. However, the present invention is not limited thereto, and the conductive wire 10 may include a conductive polymer, a composite fiber body coated with a conductive layer on a non-conductive polymer, and a carbon fiber or a combination thereof. Preferably, in order to secure a wide process window in a heating process or an organic solvent process for forming the lithium metal layer 20 to be coated on the surface of the conductive wire 10, It is preferable that the conductive wire 10 has chemical properties. For this purpose, the conductive wire 10 may be a metal fiber.

The lithium metal layer 20 can 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 an oxide, a salt, a conjugate compound, a chelate and an organic molecular compound or a combination thereof is dissolved or dispersed in an organic solvent to form a mixed solution, and the conductive wire 10 is immersed , And 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, for example, lithium hydroxide (LiOH, and LiOH · H ₂ O), lithium nitride (Li ₃ N), lithium carbonate (Li ₂ CO _3), halogenated lithium (LiF, LiCl, LiBr, LiI) , Lithium sulfide (Li ₂ S), lithium peroxide (Li ₂ O), lithium carbonate (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 active material is used, the capacity of the battery can be increased by the effect of increasing the surface area by the linear structure . Further, since pure lithium is used as the negative electrode active material, there is an advantage that the capacity of the battery can be close to the theoretical capacity and the standard reduction potential.

The carbon layer 30 coated on the lithium metal layer 20 is a diffusion path of lithium ions during charging and discharging of the battery while the carbon layer 30 is formed by the lithium metal layer 20 inside the cathode material 100A Lt; RTI ID = 0.0 > and / or < / RTI > The lithium ions transferred from the anode at the time of charging the battery are electrodeposited on the conductive wire 10 through the carbon layer 30 so that the reduction reaction of lithium is prevented by the carbon layer 30 which is a physical barrier, The lithium ion can be uniformly reduced on the wire 10 to suppress the resin phase growth of lithium.

Even when the battery is discharged, the carbon layer 30 prevents the lithium release due to ionization electrodeposited on the conductive wire 10 from occurring uniformly over the entire length of the negative electrode material 100A, , Thereby improving the discharge efficiency. As described above, the carbon layer 30 is a decelerating agent for the battery chemical reaction that may occur during charging / discharging of lithium, thereby suppressing the resin phase growth of lithium, thereby alleviating the irreversibility of the battery, 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 a high crystallinity, it is similar to a kind of graphite and can react with an electrolyte at the surface. However, the low crystalline or amorphous carbon layer does not cause the carbon layer 30 to react with the electrolyte at the time of charging / discharging, and decomposition of the electrolyte solution is suppressed, so that the lifetime of the battery can be improved. In addition, since the carbon layer 30 can contain the SP2 graphite structure having conductivity and the SP3 diamond structure having insulation property, and the conductivity of the carbon layer 30 is not required, the SP2 is smaller than the SP3 Fractions.

The thickness of the carbon layer 30 may be from 1 nm to 5000 nm, which is exemplary only and the present invention is not limited thereto. When the thickness of the carbon layer 30 is less than 1 nm, the carbon layer 30 may not function effectively as a physical barrier and may be broken due to stress 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 is more than 5 mu m, the physical distance of the diffusion barrier of lithium ions is increased, the charge / discharge efficiency and the output voltage are reduced, and the lithium metal layer 20 are relatively small in volume, the energy density can be reduced.

The carbon layer 30 may be formed using a carbon containing precursor selected from natural graphite, synthetic graphite, soft carbon, hard carbon, coke, carbon nanotubes, peeled graphite, and graphene, or mixtures thereof. The carbon layer 30 is provided by dispersing the carbon-containing precursor in a polar organic solvent and forming a carbon film on the lithium metal layer 20 by a hydrothermal synthesis method, a thermal decomposition method, a high temperature firing method, a sol-gel method or a micro synthesis method .

In another embodiment, the carbon layer 30 may be provided by coating a carbon-containing polymer compound layer on the lithium metal layer 20 by a gravure method, a spraying method, or the like, and pyrolyzing the same to leave only carbon on the lithium metal layer 20 have. The carbon-containing polymer compound layer may be formed of at least one selected from the group consisting of chitosan, glucose, sucrose, maltose, lactose, starch, glycogen, polystyrene (PS), polyethylene (PE), polypropylene (PP), polyvinyl chloride ), Polyethylene (PE), and polyvinylpyrrolidone (PVP). However, this is illustrative and the present invention is not limited thereto. For example, the carbon layer 30 may be formed directly on the lithium metal layer 20 by vapor deposition such as sputtering or evaporation .

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

For example, after the conductive wire 10 coated with the lithium metal layer 20 is immersed in the liquid organic compound or the organic solution or the liquid organic compound is wetted on the conductive wire 10, And the carbon layer 30 may be formed on the lithium metal layer 20 by thermal decomposition of the liquid organic compound. 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, pentatene, toluene, xylene, chlorobenzoic acid, benzene, hexadecyne, tetradecyne and octadecyne. The alcohol compound may be at least one selected from the group consisting of ethyl alcohol, methyl alcohol, glycerol, propylene glycol, isopropyl alcohol, isobutyl alcohol, polyvinyl alcohol, cyclohexanol, octyl alcohol, decanol, hexetecanol, Octane diol, 1,2-dodecane diol, and 1,2-hexadecane diol, or mixtures thereof. The ether compound may be at least one selected from the group consisting of octyl ether, butyl ether, hexyl ether, benzyl ether, phenyl ether, decyl ether, ethyl methyl ether, dimethyl ether, diethyl ether, diphenyl ether, tetrahydrofuran, (PEG), polypropylene glycol (PPG), polytetramethylene glycol (PTMG), polyoxymethylene (POM) and polytetrahydrofuran, or a mixture thereof. The ester compound may be at least one selected from the group consisting of polyethylene terephthalate, acrylate ester and cellulose acetate, isobutyl acetate, isopropyl acetate, allyl hexanoate, benzyl acetate, bornyl acetate, Butyl acetate, or lactone, or a mixture thereof.

In another embodiment, a lithium containing precursor is coated on the conductive wire 10 to coat an intermediate product layer containing lithium, and then a carbon-containing polymer compound layer is coated on the intermediate product layer or the above- Dipping in the container solution or using it to wet the surface of the intermediate product layer to form a carbon-containing layer. Thereafter, the lithium metal layer 20 and the carbon layer 30 derived from the organic solvent are concurrently formed through the thermal decomposition of the carbon-containing layer and the subsequent carbothermal reduction of the lithium-containing intermediate product layer (carbothermal reduction) You may. If necessary, a separate carbon-containing monomer or a natural or synthetic polymer resin that can be dissolved in the organic solvent may be further added to dissolve the organic solvent in order to increase the carbon source in the organic solvent.

In another embodiment, the negative electrode material 100A may be formed by reversing the formation order of the carbon layer 30 and the lithium metal layer 20. For example, according to the above-described one method, a carbon-containing polymer layer is coated on the conductive wire 10 or an organic solvent is applied to form a carbon-containing layer, followed by heat treatment to form a carbon layer 30, A gap can be formed between the conductive wire 10 and the carbon layer 30 by utilizing the 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 the lithium ions are transferred to the surface of the metal wire through the carbon layer 30 by the electrolytic plating method to fill the voids. According to this, there is an advantage that the lithium metal layer 20 can be formed in a wet state safely using lithium ions having high reactivity.

Referring to FIG. 1B, the linear cathode material 100B according to another embodiment may further include a separation membrane 40 coated on the carbon layer 30. FIG. The separation membrane 40 may be, for example, a polymer-based 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 straight chain polymer material or a crosslinked polymer material. The gel polyelectrolyte membrane may be a combination of any one of, for example, a plasticizer-containing polymer containing a salt, a filler-containing polymer, or a net polymer. The solid electrolyte membrane may be formed of a material such as polyethylene, polypropylene, polyimide, polysulfone, polyurethane, polyvinyl chloride, polystyrene, polyethylene oxide, polypropylene oxide, polybutadiene, cellulose, carboxymethylcellulose, nylon, Polytetrafluoroethylene, copolymers of vinylidene fluoride and hexafluoropropylene, copolymers of vinylidene fluoride and trifluoroethylene, copolymers of vinylidene fluoride and tetrafluoroethylene, vinylidene fluoride, Polyacrylate, polyvinyl acetate, polyvinyl pyrrolidone, polyvinyl pyrrolidone, polyvinyl pyrrolidone, copolymers, polymethylacrylate, polyethyl acrylate, polyethyl acrylate, polymethyl methacrylate, polyethyl methacrylate, polybutyl acrylate, polybutyl methacrylate, Either one or a combination of these It may include a polymer matrix, additives and the electrolyte.

The materials listed with respect to the above-described separator 40 are illustrative, are easy to change in shape, have excellent mechanical strength and are not torn or cracked even by deformation of the linear cathode material 100B, A material having excellent ion conductivity can be selected as a material for the separation membrane 40. [

The separation membrane 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 laminate of a single layer film formed of different materials. For example, the laminate may have a structure including a ceramic coating film on the surface of a polymer electrolyte membrane such as polyolefin. The thickness of the separation membrane 40 may be in the range of 5 占 퐉 to 300 占 퐉, preferably 10 占 퐉 to 40 占 퐉, and more preferably 10 占 퐉 to 25 占 퐉, in consideration of durability, shutdown function and safety of the battery.

In some embodiments, the separation membrane 40 may have a plurality of pores 40H exposing a portion of the surface of the carbon layer 30. The pores 40H can improve the charging and discharging efficiency and speed of the linear anode material 100B by providing the penetration space of the electrolyte and the transmission path of lithium ions.

In order to form the pores 40H, a sacrificial material is added to the polymer material constituting the above-described separation membrane 40 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 irradiated with light for drying, curing, polymerization, and / or crosslinking. Thereafter, a solvent having a selective solubility to the sacrificial material is applied to the linear negative electrode material coated with the mixed material (for example, the linear negative electrode material can be immersed in the solvent) By removing the sacrificial material, the pores 40H can be formed in the place occupied by the sacrificial material.

For example, as the sacrificial material, a natural resin such as a wax and an organic solvent such as a nucleic acid, an alcohol, and a chloroform may be used as an optional solvent. Alternatively, the above-mentioned water-insoluble polymer material may be selected as a separation membrane, and the saccharide material for forming pores may be selected from the group consisting of methyl cellulose (MC), ethyl cellulose (EC), hydroxyethyl cellulose (HEC) (CMC), hydroxypropylmethylcellulose (HPMC), hydroxypropylmethylcellulose (HPC), hydroxypropylmethylcellulose (HPMC), microstalin cellulose (MCC), and carboxymethylcellulose Or a mixture thereof, coating the mixture on a linear negative electrode material, and selectively removing the water-soluble polymer material by using water or alcohol as a solvent, a separation membrane 40 having a pore . As another option, pores 40H may be formed in the separation membrane 40 by using polyolefin as a sacrificial material and using an alkane as a selective solvent.

The above-described materials are illustrative, and the present invention is not limited thereto. Other hydrophilic natural resins or synthetic resins, polyolefin-based polymers can be used, and solvents having selective solubility for the sacrificial material do not need complete cost per day for the polymeric material for the separator and do not change the morphology of the formed mixed material Solvent. For example, the solvent may be selected from the group consisting of ethanol, propanol, butanol, pentanol, hexanol, ethylene glycol, glycerol, acetone, Dimethylether, diethylether, ethylacetate, dichloromethane, acetone, tetrahydrofuran, methylene chloride, chloroform, dimethylformamide, and the like. (N-methyl-2-pyrrolidone, NMP), cyclohexane, N-methyl-pyrrolidone Or a mixture thereof.

FIGS. 2A and 2B are respectively a plan view and a perspective view illustrating the structure of the cathode assemblies 200A and 200B using the linear cathode material 100 according to various embodiments of the present invention.

Referring to FIG. 2A, the cathode assembly 200A has a nonwoven structure in which the linear anode materials 100 are extended in at least two different random directions. If the nonwoven structure has a plurality of layers of the linear anode materials 100, a cathode structure having a three-dimensional structure may be provided.

The structure of the linear anode materials 100 taken along line I-I 'is similar to that of the conductive wires 10, the lithium metal layer 20, the carbon layer 30, And optionally a separator 40. The separator 40 may be a < / RTI > The cathode assembly 200A having the nonwoven structure may have pores 100P in which different linear cathode materials 100 are superimposed on each other. The electrolyte solution is absorbed into the three-dimensional solid structure of the cathode assembly 200A through the pores 100P, and the migration of lithium ions to the linear cathode material 100 can be activated.

Referring to FIG. 2B, the cathode assembly 200B has a woven structure in which the linear cathode materials 100 are extended at least in mutually different directions. However, this is exemplary, and the linear anode materials may have mesh structures integrated with each other. The woven structure or mesh structure may be single layered or laminated to provide a three dimensional solid structure cathode structure. The linear anode materials 100 may be linear cathode materials 100A and 100B according to the embodiments described with reference to FIGS. 1A and 1B. Further, similarly to the cathode assembly 200B of FIG. 2A, the electrode assembly 200B may have pores 100P in the three-dimensional solid structure.

The cathode assemblies 200A and 200B according to the embodiment described above are arranged such that a plurality of linear anode materials 100 are arranged to have a nonwoven fabric, a woven or mesh structure so as to have a pore structure 100P, It is possible to provide a negative electrode having a three-dimensional structure, thereby providing a battery packaged in various shapes.

The electrode assemblies 200A and 200B can maintain a low resistance in the entire volume of the cathode assembly by the conductive wires, so that the internal resistance of the battery can be drastically reduced as compared with the conventional conductive material. In addition, the electrode assemblies 200A and 200B can provide a negative electrode having a long life while ensuring an energy density close to the theoretical capacity of lithium while suppressing the resin phase growth of lithium by the carbon layer while using lithium itself as an active material.

By linearly arranging the negative electrode materials in three different directions such as nonwoven fabric or weaving structure and arranging them in three dimensions, it is possible to provide not only pores but also the linearity of the reaction sites of oxidation and reduction of lithium in the three- Can be provided. As a result, lithium that permeates into the three-dimensional structure of the cathode through the pores and is electrodeposited on the surfaces of the conductive wires can not grow uniformly in any specific direction within the three-dimensional space. As a result, according to the embodiment of the present invention, the resinous growth of lithium in the cathode assembly can be suppressed.

The nonwoven fabric and the woven structure relating to the arrangement of the negative electrode assembly are illustrative, and the present invention is limited thereto. For example, it should be understood that the linear anode materials 100 may have processability with other arrangements such as lattice patterns by mechanical processes such as blending, interlacing, or blending.

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

Referring to FIGS. 3A and 3B, the linear negative electrode materials 100 include the conductive wire 10 and the lithium metal layer 20 coated on the conductive wire 10, It is the same as the linear negative electrode material. However, the carbon layer 30 coated on the lithium metal layer 20 is extended and shared on the adjacent conductive wires 10. Optionally, a separation membrane 40 may be further formed on the carbon layer 30. In this case, the separation membrane 40 may be shared by the plurality of linear cathode materials 100.

As described above, the carbon layer 30 of the shared shape is formed by forming the conductive wires 10 coated with the lithium metal layer 20 in advance into a three-dimensional shape in the form of a nonwoven structure or a woven structure, . Similarly, the lithium metal layer 20 may be formed in common on the conductive wires so that the adjacent conductive wires 10 share the same. For this purpose, the lithium metal layer 20 can be formed through a plating process or a reduction process using a lithium-containing precursor after the conductive wires 20 are formed in advance into a three-dimensional shape in the form of a nonwoven structure or a woven structure.

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

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 sectional view showing the structure of a battery 300B according to another embodiment of the present invention.

4A, the battery 300A includes a separator SL separating the cathode AE, the anode CE, and the cathode AE from the anode CE. The cathode AE includes linear anode materials 100 forming a three-dimensional solid body. The linear negative electrode materials 100 may have a three-dimensional steric structure, for example, a nonwoven structure according to the embodiments described with reference to Fig. 2A, and Fig. 4A shows such a nonwoven structure. As another example, the linear anode materials 100 may have a regular structure, such as a woven structure, a mixed structure of a woven and nonwoven structure, or other processes that can be obtained from a fiber processing process, As shown in FIG.

The linear anode materials 100 may be a linear cathode material 100A according to the embodiments described with reference to FIG. 1A. The cathode AE may include an anode current collector 150 electrically connected to the linear anode materials 100, as shown in FIG. 4A. However, this is illustrative, and as described above, the conductive wires of the linear anode materials 100 can be electrically connected to each other. In this case, the linear cathode materials 100 themselves are electrically connected to the conductive network And the conductive network serves as an anode current collector. In this case, the current collector 150 may be omitted. If desired, the linear anode materials 100 may be electrically coupled to a lead (LD) for connection with an external terminal.

If the current collector 150 of the cathode AE is omitted as described above, both surfaces of the negative electrode made of the linear negative electrode materials 100 can be utilized as a battery chemical reaction area. For example, as shown in FIG. 4B, separators SL_1 and SL_2 are stacked on both main surfaces of a negative electrode AE made of linear negative electrode materials 100, and two positive electrodes CE_1 , CE_2 can be stacked. If the current collecting layer is omitted in this way, the thickness of the battery 300B can be reduced by that thickness, and the energy density can be improved.

Referring again to FIG. 4B, the separator SL may be 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 straight chain polymer material or a crosslinked polymer material.

The anode (CE) may include a cathode active material layer (200) and a cathode current collector layer (250). The cathode active material layer 200 may be formed of at least one metal selected from the group consisting of Ni, Co, Mn, Al, Cr, Fe, Mg, Sr, V, La and Ce and O, F, S, P, And a Li compound containing at least one non-metallic element selected from the group consisting of a combination of Li and Al. However, this is illustrative, and according to the embodiment of the present invention, since the anode has a high capacity and a high efficiency, the cathode may be a low-cost cathode active material such as VO _x .

The cathode active material layer 200 may include active material particles having a size of about 0.01 to 200 mu m and may be appropriately selected depending on the required characteristics of the 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 ultrafine graphite particles, fine carbon such as acetylene black, nano metal particle paste, or ITO (indium tin oxide) paste, , But the present invention is not limited thereto.

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

The battery can be activated by impregnating the cell with an electrolyte. The electrolyte can be a suitable aqueous electrolyte comprising a salt 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 And a nonaqueous electrolytic solution such as ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, etc. containing a lithium salt such as sodium carbonate, potassium carbonate, and the like.

The cathode CE according to the embodiment described above is arranged three-dimensionally so as to have a nonwoven fabric or a woven structure so that a plurality of linear anode materials 100 have pores 100P and are mechanically strong and easy to deform, Can be provided. In addition, since dendrite growth is suppressed by using three-dimensional arrangement with the carbon layer while using lithium itself as an active material, the standard electrode potential (0.0 V) of lithium metal can be used as an electromotive force as it is, And at the same time, the lifetime of the battery can be improved. In addition, since the irreversibility of the negative electrode such as excessive consumption of lithium is not exhibited during the reduction of lithium, as a result, the reversible capacity of the positive electrode can be increased and the capacity of the battery can be improved as a whole.

In comparison with a conventional cathode assembly formed by slurry coating an anode active material on a cathode current collector layer, pores in the three-dimensional three-dimensional structure of the cathode CE are arranged in a passage for the movement of lithium ions The mobility of lithium ions is not restricted by the cathode itself, and 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 remarkably improved as compared with the conventional negative electrode assembly. Accordingly, according to the embodiment of the present invention, efficiency of charging and discharging of the secondary battery can be improved.

FIG. 5A is a cross-sectional view showing the structure of a battery 300C according to an embodiment of the present invention, and FIGS. 5B and 5C are views for explaining an electrochemical reaction layer (EAL) of the battery 300A shown in FIG. Fig.

Referring to FIG. 5A, the battery 300C may have an electrochemical reaction layer (EAL) and a current collecting layer 250 bonded to one surface of the electrochemical reaction layer (EAL). The current collecting layer 250 may be any one of a positive electrode and a negative electrode, and is preferably a positive electrode collector layer.

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

The cathode active materials 200 may have any structure suitable for insertion into the pores 100P and may have a particle shape as shown in Fig. 5B. The electrolyte is impregnated in the electrochemical reaction layer (EAL), and as a result, lithium migration can be activated between the cathode active materials 200 and the linear cathode material 100.

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

In another embodiment, the conductive material may be a linear conductive material 210b as shown in Fig. 5C. In addition, the conductive material 210a having a particle shape 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, and the present invention is not limited thereto. For example, a cathode active material in which a conductive wire and a particle-shaped conductive material are integrally combined may be used.

In addition, a suitable binder may be added in the electrochemical reaction layer (EAL) to ensure the mechanical bonding force in the electrochemical reaction layer (EAL). In some embodiments, after mixing the linear cathode material 100 and the cathode active materials 200 to reduce the volume of the electrochemical layer (EAL), a pressure clamp may be performed, in which case thermal energy is applied It is possible.

The linear anode materials 100 may be electrically connected to each other before forming the carbon layer or the separation layer to provide a current collector structure by a three-dimensional conductive network. By bonding the leads to the current collector structure, can do. The cathode active materials 200 may be electrically coupled by the current collector 250.

According to the embodiment of the present invention, not only can the electromotive force approximate to the theoretical value can be obtained by using the lithium metal layer itself as the negative electrode active material, but also the positive electrode and the negative electrode are mixed in the electrochemical reaction layer, The internal resistance of the battery can be reduced, and the speed and efficiency of charging / discharging can be improved. Further, by making the cathode highly efficient, it is possible to provide an economical battery having the same effect even if a cathode material having a low cost such as VO _x is used as the anode.

6 is a cross-sectional view showing a 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 cathode and an anode are mixed in a single electrochemical reaction layer (EAL), similar to the battery 300C of FIG. 5A. The current collector layer 250 may be bonded to either the positive electrode or the negative electrode, preferably the positive electrode. When the current collector layer 250 is connected to the anode, the linear anode materials 100 may be provided with a cathode lead for connection with an external terminal.

The current collecting layer 250 may be formed so as to surround the electrochemical reaction layer (EAL) three-dimensionally, instead of being stacked on one major surface of the electrochemical reaction layer (EAL). The current collecting layer 250 may be a conductive polymer film, a metal layer, or a composite layer thereof. According to the embodiment of the present invention, not only the internal resistance of the battery 300D is reduced due to the increase in the area of the expanded current collector layer 250, but also the energy density is increased and the charging / And the charge / discharge speed and efficiency are improved by being generated in the entire region, so that a high output cell can be provided.

The battery structure according to the various embodiments described above can be deformed in three dimensions such as stacking, bending and winding due to excellent workability and flexibility due to the fiber characteristics of the cathode assembly, It is possible to provide a flexible battery which can be attached to a surface of the same known structure or directly to a garment, a bag and a flexible display. Further, the negative electrode assembly according to the embodiment of the present invention substantially suppresses the resinous growth of lithium to improve the irreversibility of charge and discharge, obtain an output voltage close to the theoretical value due to the reduction potential of lithium, A battery of high efficiency and long life can be obtained, so that it can be applied as a power source for an automobile or a medium to large-sized battery for electric power storage.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention as defined in the appended claims. It will be clear to those who have knowledge.

Claims (39)

A conductive wire having a metal surface as a reaction site for charging and discharging the battery by electrodeposition and desorption of lithium;
A lithium metal layer coating the metal surface of the conductive wire; And
And a carbon layer coating the lithium metal layer,
Wherein the conductive wire is a multi-layered inner core comprising the lithium metal layer and the carbon layer and the metal on the metal surface is selected from the group consisting of stainless steel, nickel, titanium, tantalum, copper, gold, platinum, ruthenium, silver, Alloy, or any combination thereof. The method according to claim 1,
And a separation layer coating the carbon layer on the carbon layer. 3. The method of claim 2,
Wherein the separator comprises a plurality of pores exposing a surface of the carbon layer. delete delete The method according to claim 1,
Wherein the conductive wire comprises a conductive polymer or a composite fiber body provided with the metal surface on a non-conductive polymer. Conductive wires extending from at least two different directions to form a three-dimensional solid body having pores and having a metal surface serving as a reaction site for charging and discharging the battery by electrodeposition and desorption of lithium;
A lithium metal layer coating the metal surface of the conductive wires; And
A carbon layer which is a physical barrier for coating the lithium metal layer and suppressing dendritic growth of lithium,
Wherein the metal on the metal surface comprises any one or combination of stainless steel, nickel, titanium, tantalum, copper, gold, platinum, ruthenium, silver, and alloys thereof. 8. The method of claim 7,
Further comprising a separator coating the carbon layer. 9. The method of claim 8,
Wherein the separator comprises a plurality of pores exposing a surface of the carbon layer. delete delete delete delete delete 8. The method of claim 7,
Wherein the conductive wire comprises a conductive polymer or a composite fiber body provided with the metal surface on a non-conductive polymer. 8. The method of claim 7,
Wherein the conductive wires have a nonwoven structure, a woven or mesh structure. And a metal surface which is a reaction site for charging and discharging the battery by electrodeposition and desorption of lithium, wherein the metal on the metal surface has a metal surface, Conductive wires comprising any one or combination of two or more of stainless steel, nickel, titanium, tantalum, copper, gold, platinum, ruthenium, silver, and alloys thereof; A lithium metal layer coating the metal surface of the conductive wires; And a carbon layer coating the lithium metal layer, wherein the conductive wires are a multi-layered internal core including the lithium metal layer and the carbon layer;
A positive electrode comprising positive electrode active materials inserted into the pores of the negative electrode and a positive electrode collector electrically connected to the positive electrode active materials; And
And a separator separating the cathode and the anode. delete 18. The method of claim 17,
Wherein the lithium metal layer is formed to extend on adjacent conductive wires. 18. The method of claim 17,
Wherein the carbon layer is formed to extend on the lithium metal layer on adjacent conductive wires. 18. The method of claim 17,
Wherein the separator is coated on the carbon layer of the negative electrode. delete 22. The method of claim 21,
Wherein the separator has a plurality of pores exposing a surface of the carbon layer. delete delete 18. The method of claim 17,
Wherein the conductive wires comprise a conductive polymer or a composite fiber body provided with the metal surface on a non-conductive polymer. 18. The method of claim 17,
Wherein the conductive wires have a nonwoven structure, a woven or mesh structure. 18. The method of claim 17,
Wherein the positive electrode current collector includes a positive electrode conductive wire extending into the pores of the three-dimensional solid body. 29. The method of claim 28,
Wherein the positive electrode conductive wire comprises a metal fiber. 18. The method of claim 17,
Wherein the cathode current collector includes a conductive foil surrounding at least a part of the surface of the three-dimensional solid body. Providing a conductive wire;
Forming a carbon-containing layer on the conductive wire;
Heat treating the carbon-containing layer to form a carbon layer, and cooling the carbon layer to form a gap between the conductive wire and the carbon layer; And
And transferring lithium ions onto the conductive wire through the carbon layer by electrolytic plating to form the lithium metal layer on the conductive wire while filling the voids. delete delete delete 32. The method of claim 31, wherein providing the conductive wire comprises:
And arranging the plurality of conductive wires so as to form a three-dimensional three-dimensional structure. 32. The method of claim 31,
Forming a separation membrane having a plurality of pores exposing a surface of the carbon layer on the carbon layer. 37. The method of claim 36, wherein forming the separator comprises:
Adding a sacrificial material to the polymer material constituting the separation membrane to provide a mixed material;
Coating the mixed material on the carbon layer; And
Applying a solvent having a selectivity to the sacrificial material to remove the sacrificial material to form the plurality of pores. ≪ RTI ID = 0.0 > 11. < / RTI > delete delete

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