KR20180121391A - Negative electrode for lithium metal battery, preparing method thereof and lithium metal battery comprising the same - Google Patents

Abstract

Disclosed in the present invention is a negative electrode for a lithium metal battery which includes: a lithium metal electrode including lithium metal or a lithium metal alloy; and a protective film disposed on at least a part of the lithium metal electrode. The protective film includes a plurality of composite particles, and the composite particles include: particles; and a coating film comprising at least one ion conductive material selected from the group consisting of an ion conductive oligomer having an ion conductive unit and an ion conductive polymer having an ion conductive unit, and disposed on at least a part of the particles. The particles include at least one selected from organic particles, inorganic particles and organic-inorganic particles having a size of more than 1 μm and not more than 100 μm. Additionally, disclosed in the present invention is a lithium metal battery comprising the negative electrode.

Description

[0001] The present invention relates to a negative electrode for a lithium metal battery, a method of manufacturing the same, and a lithium metal battery including the negative electrode,

A negative electrode for a lithium metal battery, a method of manufacturing the same, and a lithium metal battery including the same.

Lithium secondary batteries are high performance secondary batteries having the highest energy density among currently commercialized secondary batteries and can be used in various fields such as electric vehicles.

As the cathode of the lithium secondary battery, a lithium metal thin film may be used. When such a lithium metal thin film is used as a negative electrode, reactivity with a liquid electrolyte during charging and discharging is high due to high reactivity of lithium. Or a dendrite is formed on the lithium negative electrode thin film, so that the lifetime and stability of the lithium secondary battery employing the lithium metal thin film may be deteriorated, and improvement is required.

One aspect of the present invention provides a negative electrode for a lithium metal battery having a novel protective film and a method of manufacturing the same.

Another aspect is to provide a lithium metal battery including the above-described cathode and having improved cell performance.

Another aspect is to provide a novel composite electrolyte for a lithium metal battery.

On one side

A lithium metal electrode comprising a lithium metal or a lithium metal alloy; And a protective film disposed on at least a portion of the lithium metal electrode,

Wherein the protective film comprises a plurality of composite particles,

The composite particle comprising a coating film comprising at least one ion conductive material selected from the group consisting of particles and an ion conductive polymer disposed on at least a portion of the particle and having an ion conductive oligomer having an ion conductive unit and an ion conductive unit,

Wherein the particles comprise at least one selected from the group consisting of organic particles, inorganic particles and orgnic-inorganic particles having a size of more than 1 탆 and not more than 100 탆, A negative electrode for a battery is provided.

Anodic according to another aspect; The cathode described above; And an electrolyte interposed therebetween are provided.

Wherein the electrolyte comprises a composite particle, the composite particle comprising at least one ion conductive material selected from the group consisting of particles and ion conductive polymers having ion conductive oligomers and ion conductive polymers disposed on at least a portion of the particles and having ion conductive units Wherein the particles are selected from the group consisting of organic particles, inorganic particles and organic-inorganic particles having a size of more than 1 탆 and not more than 100 탆. Or more.

According to another aspect, there is provided a composite particle comprising a particle and at least one ion conductive material selected from an ion conductive polymer having an ion conductive oligomer and an ion conductive polymer disposed on at least a portion of the particle and having an ion conductive unit And a coating film comprising the above-

Wherein the particles are selected from the group consisting of lithium metal containing at least one selected from organic particles, inorganic particles and organic-inorganic particles having a size of more than 1 탆 and not more than 100 탆. A composite electrolyte for a battery is provided.

According to another aspect there is provided a lithium metal anode comprising a cathode, a lithium metal or a lithium metal alloy, and a lithium metal battery interposed therebetween and comprising the composite electrolyte described above.

Obtaining a composition for forming a protective film obtained by mixing a composite particle and a solvent according to another aspect; And

And forming a protective film by coating and drying the composition for forming a protective film on a lithium metal electrode, wherein the composite particle comprises particles and at least a portion of the particles, And at least one ion conductive polymer selected from the group consisting of an ion conductive polymer having an ion conductive polymer and an ion conductive oligomer having an ion conductive unit, wherein the particles have an average particle size of more than 1 mu m and an organic particle having a size of 100 mu m or less there is provided a method of manufacturing a negative electrode for a lithium metal battery comprising at least one selected from the group consisting of an organic particle, an inorganic particle and an organic-inorganic particle.

After coating the above protective film forming composition on a lithium metal electrode and drying to form a protective film, a polymerizable oligomer composition obtained by mixing a polymerizable oligomer and a solvent is coated on the coated and dried product, and a crosslinking reaction is carried out The method comprising the steps of:

The negative electrode for a lithium metal battery according to an exemplary embodiment has a protective film having improved current density uniformity and lithium ion mobility during lithium electrodeposition. By using such a cathode, it is possible to manufacture a lithium metal battery in which the volume change during charging is effectively suppressed and the cycle life and the discharge capacity are improved.

1A is a view for explaining the principle of a cathode for a lithium metal battery according to one embodiment.
FIG. 1B shows a case where a coating film is not formed on the surface of the particles contained in the protective film for comparison with FIG. 1A.
1C to 1E, 1O, 1P, and 1Q schematically illustrate the structure of a cathode for a lithium metal battery according to one embodiment.
FIGS. 1F and 1G are diagrams for explaining the principle of suppressing and guiding lithium dendrite in a protective film of a cathode for a lithium metal battery according to one embodiment.
FIGS. 1 H to IL illustrate schematically the structure of a lithium metal battery according to one embodiment.
FIG. 1M is a view for explaining a protective role of the lithium metal electrode in a case where the particle size of the microspheres contained in the protective film in the anode for a lithium metal battery according to an embodiment is more than about 1 μm and less than 100 μm.
FIG. 1n illustrates the protective role of the lithium metal electrode when the average particle diameter of the microspheres contained in the protective film in the negative electrode for a lithium metal battery is 1 μm or less.
FIGS. 2A and 2B are transmission electron microscope (TEM) photographs of the composite particles contained in the protective film of Example 1. FIG.
FIG. 2C is a TEM photograph of a poly (styrene-b-divinylbenzene) block copolymer microsphere which is a starting material for forming a composite particle of Preparation Example 1 for comparison with the composite particles of FIGS. 2A and 2B.
2 (d) is a scanning electron microscope (SEM) photograph of a cathode prepared according to Example 1. Fig. FIGS. 3A and 3B are SEM photographs of a lithium metal battery manufactured according to Example 9. FIG.
FIGS. 3C and 3D are SEM photographs of a lithium metal battery manufactured according to Comparative Example 1. FIG.
4 is a graph of cell lifetime of a lithium metal battery produced according to Example 9 and Example 9A.
FIGS. 5 and 6 show the laminated structure of the lithium metal battery manufactured according to the ninth embodiment and the example 9A, respectively.
Figs. 7A to 7C show results of lithium electrodeposition simulation analysis conducted according to Evaluation Example 5. Fig.
FIG. 8A shows a Nyguist plot of the impedance measurement results when the elapsed time after the production of the lithium metal battery according to Example 9C and Comparative Example 1 was 24 hours.
8B shows a Nyguist plot of the impedance measurement result when the elapsed time after manufacture of the lithium metal battery manufactured according to Example 9B is 24 hours.
8C shows a laminated structure of a lithium symmetric cell manufactured according to Example 9B.
FIGS. 9A-9C illustrate a state in which particles are disposed on a lithium metal surface in a protective film according to an embodiment. FIG.
10 shows a structure of a lithium metal battery according to another embodiment.

Exemplary cathode for a lithium metal battery, a lithium metal battery including the anode, and a composite electrolyte for a lithium metal battery will now be described in detail with reference to the accompanying drawings.

A lithium metal electrode comprising a lithium metal or a lithium metal alloy; And a protective film disposed on at least a portion of the lithium metal electrode, wherein the protective film includes a plurality of composite particles. The composite particle comprising a coating film comprising at least one ion conductive material selected from the group consisting of particles and an ion conductive polymer disposed on at least a portion of the particle and having an ion conductive oligomer having an ion conductive unit and an ion conductive unit, A negative electrode for a lithium metal battery comprising at least one selected from organic particles, inorganic particles and organic-inorganic particles having a size of more than 1 탆 and not more than 100 탆, The Young's modulus of the protective film is 10 ⁶ Pa or more, for example, 10 ⁶ to 10 ⁹ Pa or 5 × 10 ⁶ Pa to 5 × 10 ⁸ Pa.

The composite particles have an interconnected structure.

As used herein, the term " interconnected " includes both instances where the multiparticulates are physically and / or chemically linked and / or linked together. The term " interconnected " means connected and / or coupled through bridging or the like.

The lithium metal or the lithium metal alloy has a large electric capacity per unit weight, and it is possible to realize a high capacity battery. However, the lithium metal or the lithium metal alloy may cause a short circuit between the anode and the cathode due to the growth of the dendrite in the process of removing / attaching lithium ions. An electrode including a lithium metal or a lithium metal alloy has a high reactivity to an electrolyte and may cause a side reaction with an electrolyte, thereby deteriorating the cycle life of the battery. In order to compensate for this, a protective film that can complement the surface of a lithium metal electrode containing lithium metal or a lithium metal alloy is required.

Accordingly, the present inventors provide a novel protective film for a lithium metal battery which can overcome the above-described problems. The protective film contains a coating film containing an ion conductive material disposed on at least a part of the particles on the surfaces of the interconnected particles constituting the protective film, thereby improving the current density uniformity characteristic and exhibiting excellent mechanical properties during the lithium electrodeposition. The protective film for a lithium metal battery further improves the current density uniformity characteristic particularly at a high rate.

FIG. 1A schematically shows a structure of a cathode for a lithium battery according to one embodiment.

Referring to FIG. 1, a protective film is formed on a lithium metal electrode 11 including a lithium metal or a lithium metal alloy, and the protective film contains interconnected particles 13. A coating film (14) containing at least one ion conductive material selected from an ion conductive oligomer having an ion conductive unit and an ion conductive polymer having an ion conductive unit is disposed on the particle (13). The coating film 14 may be arranged in a continuous film form on the particles 13 or in a discontinuous film form as shown in Fig. The particles 13 form a non-ion conductive core and the coating film 14 forms an ion conductive shell so that the composite particles 15a have a core-shell microsphere structure. In Figs. 1A and 1B, arrows indicate directions of movement of lithium ions.

The protective film of FIG. 1A can form an ion conduction path along the surface of the coating film 14 as compared with the case where the coating film is not disposed on the particles 13 (FIG. 1B), and lithium ions can move through the micropores. As compared with the case where the coating film is not disposed on the surface of the particles 13 as the lithium ion conduction becomes possible along the surface of the coating film 14 of the particles 13, the site where lithium can be electrodeposited on the surface of the lithium electrode By being uniformly present, lithium can be electrodeposited evenly. The interface resistance of the protective film and the lithium metal electrode 11 is reduced so that the ionic conductivity of the protective film is 10 ^-3 S / cm or more, for example, 10 ^-3 S / cm to 10 S / cm or 5 10 ^-2 S / cm to 1 S / cm. When such a cathode is used, the volume change during charging can be effectively suppressed and uniformized.

In the protective layer according to one embodiment, the particles contain a block copolymer such as styrene-divinylbenzene block copolymer and have an interconnected structure and have excellent alignment characteristics and dispersion characteristics.

In an ion conductive polymer having an ion conductive unit having an ion conductive unit and an ion conductive unit, the ion conductive unit is a C1-C30 alkylene oxide group, - {Si (R) (R ') - O-} _b- or - ₂ CH ₂ O) _a - {Si (R) (R ') - O-} _b -, and R and R' are independently of each other hydrogen or a C 1 -C 10 alkyl group. a and b are each independently an integer of 1 to 10, for example, an integer of 1 to 5. R and R 'are, for example, methyl, ethyl, propyl or butyl groups.

One or more ion conductive materials selected from the ion conductive oligomer having the ion conductive unit and the ion conductive polymer having the ion conductive unit are, for example, polyethylene glycol, polypropylene glycol, poly (ethylene glycol-co-propylene glycol-co-ethylene glycol ), Poly (propylene glycol-co-ethylene glycol-co-propylene glycol), polysiloxane, poly (oxyethylene) methacrylate (POEM), poly (ethylene glycol) diacrylate (Ethylene glycol) dimethacrylate (PEGDMA), poly (propylene glycol) dimethacrylate (PPGDMA), poly (ethyleneglycol) urethane diacrylate) Poly (ethylene glycol) urethane dimethacrylate, polyester diacrylate, poly (ethylene glycol) urethane dimethacrylate, Polyester dimethacrylate, poly (ethyleneglycol) urethane triacrylate, poly (ethyleneglycol) urethane trimethacrylate, trimethyl (meth) acrylate, Trimethylolpropane triacrylate and trimethylolpropane trimethacrylate derived from at least one selected from trimethylolpropane triacrylate, trimethylolpropane trimethacrylate and trimethylolpropane trimethacrylate, poly (ethylene oxide) Poly (methyl methacrylate) (PPO grafted PMMA) grafted with poly (methyl methacrylate) (PEO grafted PMMA), poly (propylene oxide) grafted poly Methacrylate) (PBO grafted PMMA), polysiloxane grafted poly (methyl methacrylate) Poly (methyl methacrylate) grafted with polysiloxane grafted PMMA, poly (ethylene glycol) (PEG) grafted with PEO grafted PMMA, polypropylene glycol (PPG) (PPG grafted PMMA).

The ion conductive material may be selected from, for example, one selected from the group consisting of polyethylene glycol, polypropylene glycol, poly (ethylene glycol-co-propylene glycol-co-ethylene glycol), poly (propylene glycol-co-ethylene glycol-co-propylene glycol) Or more.

The weight average molecular weight of the ion conductive material is from 200 to 100,000 Daltons, for example, from 200 to 10,000 Daltons, for example, from 200 to 5,000 Daltons, for example, from 200 to 600 Daltons. When the weight average molecular weight of the ion conductive material is in the range described above, the film-forming property of the coating film to the particles is excellent.

The thickness of the coating film is 1 μm or less, for example, 500 nm or less, for example, 5 to 500 nm, for example, 10 to 200 nm, for example, 20 to 100 nm. When the thickness of the coating film is within the above-mentioned range, lithium ion migration can be made more freely in the cathode, and current density uniformity is excellent when lithium is deposited on the lithium metal electrode.

The content of the ion conductive material in the coating film in the protective film according to one embodiment is 10 to 50 parts by weight, for example, 10 to 45 parts by weight, for example, 10 to 35 parts by weight, for example, 15 to 50 parts by weight, To 30 parts by weight. When the content of the ion conductive material is in the above range, the mechanical strength of the protective film is excellent, thereby effectively suppressing the growth of lithium dendrite, and excellent current density uniformity characteristics upon lithium electrodeposition on the lithium metal electrode.

The ion conductive material can serve as a binder to help immobilize the particles on the lithium metal electrode in the protective layer, and any material that can improve the mechanical strength of the protective layer can be used.

The conductivity of the ion conductive material in the coating film is 5 times or more, for example, 10 times or more, for example, 25 times or more, for example, 100 times or more, as compared with the conductivity of the material of the remaining regions except for the composite particles. The difference in conductivity may vary depending on the thickness of the coating film.

When the thickness of the coating film according to one embodiment is 0.2 μm (200 nm), the conductivity of the ion conductive material is 25 times or more, for example, 25 to 100 times, For example, when the current is 25 to 89 times, the current density uniformity characteristic of the cathode is excellent.

When the thickness of the coating film according to one embodiment is 0.1 mu m (100 nm), the conductivity of the ion conductive material is 50 times or more, for example, 50 to 100 times greater than the conductivity of the material other than the composite particles in the protective film, For example, 50 to 89 times, the current density uniformity characteristic of the cathode is excellent.

The protective film according to one embodiment includes a lithium salt or a liquid electrolyte.

When the protective film includes a liquid electrolyte, an ion conductive path can be formed through the liquid electrolyte, thereby improving the conductivity of the cathode. By using such a negative electrode, a lithium metal battery having stable cycle characteristics can be manufactured.

The liquid electrolyte includes at least one selected from an organic solvent, an ionic liquid, and a lithium salt.

The liquid electrolyte in the protective film may comprise from 30 to 60% by volume, for example from 35 to 55% by volume, for example from 40 to 50% by volume, based on the total volume of the protective film. The liquid electrolyte occupies, for example, 40 to 50% by volume in the protective film.

The size of at least one particle selected from organic particles, inorganic particles and organic particles in the protective film according to one embodiment may be 5 to 75 탆.

The size of at least one particle selected from among organic particles, inorganic particles and organic particles in the protective film according to one embodiment is, for example, 1.1 to 50 μm, for example, 1.1 to 25 μm, for example, 1.3 to 28 μm For example, 1.5 to 20 占 퐉, for example, 1.5 to 10 占 퐉.

The particles in the protective film according to one embodiment may be, for example, organic particles.

The inorganic particles are more excellent in strength than the organic particles, but a binder may be required in the production of the protective film, and the resistance characteristic in the protective film due to the functional groups such as the hydroxyl groups present on the surface of the inorganic particles becomes larger .

The particles may be, for example, poly (styrene-co-divinylbenzene) copolymer microspheres having an average particle size of about 3 탆 in a weight ratio of 1: 1 and poly (styrene-co-divinylbenzene) (Styrene-co-divinylbenzene) copolymer microspheres having an average particle size of about 3 mu m and a poly (styrene-co-divinyl) copolymer having an average particle diameter of about 1.3 mu m Benzene copolymer microspheres or poly (styrene-co-divinylbenzene) copolymer microspheres having an average particle size of about 3 占 퐉 in a 1: 1 weight ratio and poly (styrene-co-divinylbenzene ) Copolymer microspheres.

According to one embodiment, the particles are microspheres having a monomodal particle size distribution. The monododal particle size distribution can be measured by using a particle diameter analyzer (Dynamic Light Scattering: DLS, Nicomp 380), wherein the standard deviation is 1% or more to less than 40%, for example, 2 to 25% For example, within a range of 3 to 10%.

The protective film according to one embodiment may further contain at least one selected from an ion conductive polymer and an ionic liquid, in addition to the composite particles, the lithium salt and the liquid electrolyte described above.

As the ion conductive polymer, for example, polyethylene oxide, polypropylene oxide, polyethylene derivatives, poly (ethylene-co-vinyl acetate) and the like are used.

When the protective film contains an ion conductive polymer, the content of the particles of the composite particles is 1 to 100 parts by weight, for example 1 to 50 parts by weight, for example 5 to 30 parts by weight, based on 100 parts by weight of the ion conductive polymer .

When the protective film further comprises a lithium salt and an ion conductive polymer, the content of the lithium salt may be 1 to 100 parts by weight, for example, 1 to 50 parts by weight, for example 5 to 30 parts by weight, to be.

When the protective film further comprises an ionic polymer and an ionic liquid, the content of the ionic liquid is 1 to 100 parts by weight, for example, 1 to 50 parts by weight, for example, 5 to 50 parts by weight, based on 100 parts by weight of the ion- 30 parts by weight.

The ionic liquid, the lithium salt, and the organic solvent contained in the protective film can be used as long as they are commonly used in a lithium metal battery.

Young's modulus of the protective film is 10 ⁶ Pa or more, for example, 10 ⁷ Pa or more or 10 ⁸ Pa or more. The Young's modulus of the protective film, for example ^{from 6} to 10 10 ¹¹ Pa, or for example, 10 ⁷ to 10 ¹⁰ Pa, or 10 ⁷ to 10, the Young's modulus of the protective film is very excellent as a ⁹ Pa is extremely excellent in the mechanical properties.

Young's modulus has the same meaning as "tensile modulus". The tensile modulus is measured using a dynamic mechanical analysis system (DMA800, TA Instruments), and the protective film specimen is prepared using ASTM standard D412 (Type V specimens). And the tensile modulus of the protective film is measured at a rate of 5 mm per minute at 25 ^° C and a relative humidity of about 30%. The tensile modulus is evaluated from the slope of the thus obtained stress-strain curve.

The Young's modulus of the protective film according to one embodiment can easily measure the method of measuring the Young's modulus and the apparatus for using the apparatus according to the present invention by separating the protective film of the battery, that is, the isolated protective layer.

At least one of the particles in the protective film may have a crosslinked structure. The particles having a chemically or physically crosslinked structure are defined as including organic particles of a crosslinked polymer obtained from a polymer having a crosslinkable functional group, inorganic particles having a structure crosslinked by a crosslinking functional group present on the surface, and the like . Examples of the crosslinkable functional group include functional groups participating in the crosslinking reaction such as acrylic group, methacrylic group and vinyl group.

Cross-linking may proceed by applying heat or by irradiating light such as UV. Here, heat or light can be applied in a range that does not adversely affect the lithium metal electrode.

The particles having a chemically crosslinked structure are crosslinked using chemical methods (i.e., chemical reagents) so as to enable bonding of crosslinkable functional groups present in the material constituting the particles. And particles having a physically crosslinked structure are crosslinked by a physical method. Physical methods include, for example, heating to reach the glass transition temperature of the polymer constituting the particles, although the crosslinking is not formed by the chemical reagent so as to enable the bonding of the crosslinkable functional groups. Crosslinking may occur within the particle itself and may also proceed between adjacent particles in the protective film.

The thickness of the lithium metal electrode is 100 mu m or less, for example, 80 mu m or less, or 50 mu m or less, or 30 mu m or less, or 20 mu m or less. According to another embodiment, the thickness of the lithium metal electrode is 0.1 to 60 占 퐉. Specifically, the thickness of the lithium metal or the lithium metal alloy is 1 to 25 占 퐉, for example, 5 to 20 占 퐉, specifically 10 to 20 占 퐉.

The particles contained in the protective film may have a spherical shape, a rod shape, an elliptical shape, a radial shape, or the like or a combination thereof.

When the particles are spherical, for example, they may be microspheres having an average particle size exceeding 1 탆 and a size of 100 탆 or less. The average particle size of the microspheres may be, for example, 1.5 to 75 占 퐉, 1.5 to 50 占 퐉, or 1.5 to 20 占 퐉 or, for example, 1.5 to 10 占 퐉.

If the particle size exceeds 100 mu m, the thickness of the protective film becomes thick, and the total thickness of the cell increases, so that the energy density characteristic of the lithium metal battery may be deteriorated. And the porosity in the protective film is increased, so that the liquid electrolyte can be easily contacted with the lithium metal electrode.

When the particle size is 1 mu m or less, a lithium metal battery employing a protective film containing particles of this size has a lithium metal electrodeposited density characteristic that a lithium metal battery employing a protective film in which the particle size is more than 1 [ As compared with the case of FIG.

As used herein, the term " size " refers to the average particle size when the particles are spherical. If the particles are rod-shaped or elliptical, the size indicates the major axis length. If the particles are of the rod-type type, the ratio of the transverse and longitudinal axes can be, for example, from 1: 1 to 1:30, for example from 1: 2 to 1:25, for example from 1: 5 to 1:20 .

As used herein, the term " average particle size " or " average particle diameter " means that 50% or more of the particles in a distribution curve, (D50), wherein the total number of accumulated particles is 100%. The average particle size can be measured according to methods known to those skilled in the art. For example, the average particle size is determined by the particle size (TEM) or SEM image. As another method of measuring the average particle size, there is a method using a measuring device using dynamic light scattering. According to this method, The number of particles can be counted, from which the average particle size can be calculated.

Porosity is defined herein as the void volume (i.e., voids or pores) measured in a material and is determined by the volume percentage of voids in the material based on the total volume of the material.

FIG. 1M is a view for explaining a protective role of the lithium metal electrode in the case where the particle size of the microspheres contained in the protective film in the negative electrode for a lithium metal battery according to an embodiment is more than about 1 μm and 100 μm, This is to explain the protective role of the lithium metal electrode when the average particle diameter of the microspheres contained in the protective film in the negative electrode for a lithium metal battery is 1 탆 or less.

Referring to FIG. 1M, a protective film 12 including a microsphere 13a is laminated on a lithium metal electrode 11. The surface coating fraction of the microspheres contained in the protective film formed on the lithium metal electrode and the particle spacing of the microsphere are factors that directly affect the protective film function of the lithium metal electrode. As used herein, the term " surface coating fraction " refers to the surface area of a lithium metal electrode comprising a protective film over the entire surface area of the lithium metal electrode. The surface coating fraction is, for example, about 80%, about 85%, about 90%, or about 100% of the total surface area of a lithium metal electrode.

The lithium metal electrode 11 is, for example, a lithium metal and the lithium metal electrode 11 has a thickness of, for example, 5 to 50 μm, for example, 10 to 30 μm, for example, 15 to 25 μm ㎛, and its surface step is about ± 1 ㎛. In protecting the lithium metal electrode having such a surface step difference, when the average particle diameter is more than 1 탆 and less than 100 탆, the use of the microspheres 13a is very excellent in protecting the lithium metal electrode.

In contrast, when the protective film 12 stacked on the lithium metal electrode 11 as shown in FIG. 1n contains microspheres having an average particle diameter of 1 μm or less, for example, a microsphere containing a particle diameter of 5 nm to 300 nm The aggregation and surface coating fraction of the microspheres are reduced. As a result, the degree of porosity in the protective film becomes large, so that it is advantageous for the liquid electrolyte to contact the lithium metal.

The particles of the protective film may be any polymer used for forming a protective film.

According to one embodiment, the particles of the protective film may further include at least one selected from a homopolymer having ion conductivity, a copolymer and a crosslinked polymer, and examples thereof include a block copolymer containing polystyrene or a styrene-based repeating unit .

According to another embodiment, the particles of the protective film may be made of a polymer having a low wettability to a liquid electrolyte.

The particles of the protective film may include at least one selected from i) a copolymer containing polystyrene, a styrene repeating unit, a copolymer containing a repeating unit having a crosslinkable functional group, and ii) a crosslinking polymer. The particles of the protective film may be a polymer (homopolymer or copolymer) containing a styrene-based repeating unit. In the case of a polymer having a styrenic repeating unit, the polymer has hydrophobicity so that it does not adversely affect the lithium metal electrode and has little electrolyte wettability, so that the reactivity between the lithium metal electrode and the electrolyte can be minimized.

At least one of the particles is selected from the group consisting of polystyrene, poly (styrene-divinylbenzene) copolymer, poly (methyl methacrylate-divinylbenzene) copolymer, poly (ethyl methacrylate-divinylbenzene) Poly (propyl methacrylate-divinylbenzene) copolymers, poly (styrene-ethylene-butylene) copolymers, poly Poly (styrene-acrylonitrile) copolymer, poly (styrene-vinylpyridine) copolymer, poly (acrylonitrile-butadiene-styrene) copolymer Acrylonitrile-butadiene-styrene) copolymers, poly ((C1-C9 alkyl) acrylate-acrylonitrile- Butadiene-sty (C1-C9 alkyl methacrylate-butadiene-styrene) copolymers, poly ((C1-C9) alkyl acrylate-butadiene-styrene) copolymers, ) Copolymer and at least one polymer A selected from the group consisting of poly (acrylonitrile-styrene- (C1-C9 alkyl acrylate) copolymers and crosslinked polymers of the polymer A).

Examples of poly (C1-C9 alkyl methacrylate-butadiene-styrene) copolymers include poly (methyl methacrylate-butadiene-styrene) copolymers, poly (ethyl methacrylate- (Methacrylate-butadiene-styrene) copolymer or a poly (hexyl methacrylate-butadiene-styrene) copolymer. Examples of the poly (styrene-C1-C9 alkyl acrylate) Ethyl acrylate) copolymer.

The polymer A has a crosslinkable group.

The poly (styrene-divinylbenzene) copolymer is represented by the following formula (1).

[Chemical Formula 1]

In the general formula (1), a and b are mole fractions, 0.01 to 0.99, respectively, and the sum of a and b is 1. In formula (1), a is, for example, from 0.95 to 0.99, for example from 0.96 to 0.99, specifically from 0.98 to 0.99, and b is from 0.01 to 0.05, for example from 0.01 to 0.04, .

The poly (styrene-divinylbenzene) copolymer is represented by the following formula (1a).

[Formula 1a]

The poly (styrene-divinylbenzene) copolymer is represented by the following formula (1b).

[Chemical Formula 1b]

The poly (acrylonitrile-butadiene-styrene) copolymer may be represented by the following general formula (2).

(2)

In Formula 2, x, y and z are mole fractions, 0.01 to 0.99 regardless of each other, and the sum of x, y, and z is 1.

In Formula 2, x is 0.1 to 0.35, y is 0.05 to 0.55, and z is 0.2 to 0.7. For example, x is 0.15-0.35, y is 0.05-0.3, and z is 0.4-0.6.

The degree of polymerization of the poly (styrene-divinylbenzene) copolymer represented by the formula (1) and the poly (acrylonitrile-butadiene-styrene) copolymer represented by the formula (2) is 2 to 5,000, for example, 5 to 1,000 .

The poly (styrene-divinylbenzene) copolymer represented by Formula 1 and the poly (acrylonitrile-butadiene-styrene) copolymer represented by Formula 2 may be, for example, block copolymers.

The crosslinked polymer refers to a polymer in which a polymer has functional groups capable of crosslinking to form a crosslinking bond therebetween. The crosslinked polymer may be a crosslinked product obtained from a copolymer containing a repeating unit having a crosslinkable functional group.

The crosslinked polymer is a crosslinked product of a block copolymer having a polyethylene oxide block having an acrylate functional group and a polystyrene block; Or C1-C9 alkyl (meth) acrylate, C2-C9 alkenyl (meth) acrylate, C1-C12 glycol di (meth) acrylate (C1- di (meth) acrylate (for example, C1-C12 glycol diacrylate), poly (C2-C6 alkylene glycol) di (meth) acrylate And crosslinked products of one compound selected from polyol (meth) acrylates (for example, polyol polyacrylate) and polyol (poly (C2-C6 alkylene glycol) diacrylate). Examples of the C1-C9 alkyl (meth) acrylate include hexyl acrylate, 2-ethylhexyl acrylate, and allyl methacrylate as an example of C2-C9 alkenyl (meth) acrylate .

Examples of glycol diacrylates include 1,4-butanediol diacrylate, 1,3-butylene glycol diacrylate, 1,6-hexanediol 1,6-hexanediol diacrylate, ethylene glycol diacrylate, and neopentyl glycol diacrylate. And polyalkylene glycol diacrylates include, for example, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, tripropylene glycol diacrylate, polyethylene glycol diacrylate, and polypropylene glycol acrylate There is a rate.

Polyol polyacrylates include, for example, trimethylol propane triacrylate, pentaerythritol tetraacrylate, or pentaerythritol triacrylate.

The crosslinked polymer refers to, for example, a poly (styrene-divinylbenzene) copolymer, poly (methyl methacrylate-divinylbenzene), or a crosslinked product of the polymer A described above. Here, the polymer A has a crosslinkable functional group, and the polymer is replaced by crosslinking thereof.

When the above-mentioned copolymer contains a styrene-based repeating unit, the content of the styrene-based repeating unit is 65 to 99 parts by weight, 80 to 99 parts by weight, 90 to 99 parts by weight, based on 100 parts by weight of the copolymer, 96 to 99 parts by weight.

In the case where the copolymer contains divinylbenzene, the content of divinylbenzene is 1 to 35 parts by weight, 1 to 20 parts by weight, 1 to 10 parts by weight, 1 to 4 parts by weight, In the range of 3 to 7 parts by weight, specifically 5 parts by weight.

(Poly (methyl methacrylate-divinylbenzene) copolymer, poly (methyl methacrylate-divinyl benzene) copolymer, poly (ethyl methacrylate-divinyl benzene) (Meth) acrylate monomer, a repeating unit of repeating units of methyl methacrylate, ethyl methacrylate, pentyl methacrylate, butyl methacrylate, or propyl methacrylate in a poly (propyl methacrylate-divinylbenzene) The content is 65 to 99 parts by weight, 80 to 99 parts by weight, and 90 to 99 parts by weight, for example, 96 to 99 parts by weight, based on 100 parts by weight of the copolymer.

(Styrene-acrylonitrile) copolymers, poly (styrene-vinylpyridine) copolymers, poly (styrene-acrylonitrile) copolymers, (Acrylonitrile-butadiene-styrene) copolymer, poly (acrylonitrile-ethylene-propylene-styrene) copolymer, poly (methyl methacrylate- acrylonitrile- (C1-C9 alkyl) acrylate copolymer in a poly (styrene- (C1-C9 alkyl) acrylate) copolymer and a poly (acrylonitrile-styrene- Is from 65 to 99 parts by weight, from 80 to 99 parts by weight, and from 90 to 99 parts by weight, for example, from 96 to 99 parts by weight, based on 100 parts by weight of the total weight of the copolymer. In the case of the above-mentioned copolymers, the content of the remaining repeating units other than the styrene-based repeating units may be varied in various proportions except for the content of the styrene-based repeating units in the copolymer. The above-mentioned copolymers include all of block copolymers, random copolymers, alternating copolymers, graft copolymers and the like. The weight average molecular weight of such copolymers is from 10,000 to 200,000 daltons.

In the present specification, the first repeating unit and the second repeating unit each represent a first and a second repeating unit which are different from each other in the above-mentioned copolymer. The block containing the first repeating unit has a weight average molecular weight of 10,000 Daltons or more, for example, 10,000 to 500,000 Daltons, specifically 15,000 to 400,000 Daltons. According to another embodiment, the weight average molecular weight of the block containing the first repeating unit is 20,000 to 200,000 Daltons. The content of the block containing the first repeating unit is 20 to 50 parts by weight, for example, 20 to 40 parts by weight, for example, 22 to 30 parts by weight, based on 100 parts by weight of the total weight of the block copolymer. When a block containing such a first repeating unit is used, a protective film excellent in mechanical properties such as strength can be obtained.

The weight average molecular weight of the block containing the second repeating unit is at least 10,000 Daltons, for example 10,000 to 510,000 Daltons, specifically 15,000 to 400,000 Daltons. According to another embodiment, the weight average molecular weight of the block containing the second repeating unit is 20,000 to 200,000 Daltons. When a block containing the second repeating unit having such a weight average molecular weight is used, a protective film excellent in ductility, elasticity and strength can be obtained.

The weight average molecular weights herein are measurable according to methods well known to those skilled in the art. For example, the weight average molecular weight can be measured according to the gel permeation chromatography (GPC) method (using polystyrene standards).

The block copolymer is at least one selected from a diblock copolymer (A-B) and a triblock copolymer (A-B-A 'or B-A-B').

The particles of the protective film may be selected from the group consisting of polyvinylpyridine, polyvinylcyclohexane, polyglycidyl acrylate, poly (2,6-dimethyl-1,4-phenylene oxide), polyolefin, poly (tertbutyl vinyl ether), polycyclohexyl At least one selected from the group consisting of vinyl ether, polyvinyl fluoride, poly (styrene-maleic anhydride) copolymer, polyglycidyl methacrylate, polyacrylonitrile and polymeric ionic liquids (PIL) . ≪ / RTI >

The particles of the protective film may be selected from the group consisting of a poly (styrene-divinylbenzene) copolymer, a poly (methyl methacrylate-divinylbenzene) copolymer, a poly (ethyl methacrylate-divinylbenzene) Poly (methyl methacrylate-divinylbenzene) copolymers, poly (butyl methacrylate-divinylbenzene) copolymers, poly (propyl methacrylate-divinylbenzene) (Ethyl acrylate-divinylbenzene) copolymer, poly (pentyl acrylate-divinylbenzene) copolymer, poly (butyl acrylate-divinylbenzene) copolymer, poly (propyl acrylate-divinylbenzene) And a poly (acrylonitrile-butadiene-styrene) copolymer.

When the particles of the protective film include the above-mentioned crosslinked polymer, the particles are connected to each other through crosslinking, so that the mechanical strength of the protective film is excellent. The crosslinked polymer of the protective film has a degree of crosslinking of 10 to 30%, for example, 12 to 28%, for example, 15 to 25%, based on the total volume of the crosslinked polymer.

The particles of the protective film may be interconnected. The coating film of the composite particles constituting the protective film may exist in an independent phase while maintaining the pore structure formed between the particles of the protective film.

With reference to the accompanying drawings, a structure of a cathode for a lithium metal battery according to an embodiment will be described. In Figures 1A to 1D, the particles of the protective film have a microsphere shape as a non-limiting example.

As shown in FIG. 1A, the negative electrode includes a lithium metal electrode 11 made of lithium metal or a lithium metal alloy, and a protective film 12 is disposed on the lithium electrode 11. The protective film 12 contains the composite particles 15a. In the composite particle 15a, there is an empty space between the particle 13 and the particle 13, and ions can be transferred through this space. Therefore, when such a protective film is employed, the ion conductivity of the cathode can be improved. And a lithium dendrite growth space is provided through an empty space, for example, a pore structure, to guide the growth of lithium dendrite.

The lithium metal alloy includes a metal / metalloid or an oxide thereof capable of being alloyed with a lithium metal and a lithium metal. Sn, Al, Ge, Pb, Bi, Sb, Si-Y alloys (Y is an alkali metal, an alkaline earth metal, a group 13 to 16 group element, a transition metal, (Wherein Y is an alkali metal, an alkaline earth metal, a Group 13 to Group 16 element, a transition metal, a rare earth element, or a combination element thereof, and Sn is a metal element, a rare earth element or a combination element thereof and not Si) , MnOx (0 < x? 2), and the like.

The element Y may be at least one element selected from the group consisting of Mg, Ca, Sr, Ba, Ra, Sc, Y, Ti, Zr, Hf, Rf, V, Nb, Ta, Db, Cr, Mo, W, Sg, Pb, Ru, Os, Hs, Rh, Ir, Pd, Pt, Cu, Ag, Au, Zn, Cd, B, Al, Ga, Sn, In, Tl, Ge, P, As, Se, Te, Po, or a combination thereof. For example, the metal / metalloid oxide that can be alloyed with the lithium metal may be lithium titanium oxide, vanadium oxide, lithium vanadium oxide, SnO ₂ , SiO _x (0 <x <2), and the like.

1C, a lithium metal electrode 11 made of lithium metal or a lithium metal alloy is laminated on the collector 10, and a protective film 12 is disposed on the lithium electrode 11 have. The protective film 12 contains the composite particles 15a. The composite particle 15a contains a particle 13 and a coating film 14 containing an ion conductive material disposed on the particle 13 surface. Although not shown in the figure, a lithium salt or a liquid electrolyte exists in a space between the particles. The liquid electrolyte may contain a lithium salt and an organic solvent.

The coating film 14 containing an ion conductive material is included in the protective film 12 to improve the strength of the protective film 12 and to serve as a binder. In the protective film according to one embodiment, there is a crosslinked product 15 of polymerizable oligomer between the particles 13 contained in the protective film as shown in Fig. 10 and Fig. The crosslinked product 15 of the polymerizable oligomer is present in the void space between the particles 13, and the protective film 12 has an integral structure, so that it can have excellent mechanical properties. Therefore, employing such a protective film not only greatly improves the effect of suppressing the growth of lithium dendrite, but also improves the electrodeposition density of lithium at the charge and discharge and is excellent in the conductivity characteristic.

When the crosslinked product 15 of the polymerizable oligomer has ionic conductivity, ions can be transferred through it. Therefore, when such a protective film is employed, the ion conductivity of the cathode can be improved.

Polymerizable oligomers are understood herein as including the polymerizable monomers. The weight average molecular weight of the polymerizable oligomer is, for example, 2,000 or less.

The polymerizable oligomer may be selected from the group consisting of diethylene glycol diacrylate (DEGDA), triethylene glycol diacrylate (TEGDA), tetraethylene glycol diacrylate (TTEGDA), polyethylene glycol diacrylate (PEGDA), dipropylene glycol diacrylate (DPGDA), tripropylene glycol diacrylate (TPGDA), ethoxylated trimethylolpropane triacrylate (ETPTA), acrylate-functionalized ethylene oxide, 1,6 Ethoxylated neopentyl glycol diacrylate (NPEOGDA), propoxylated neopentyl glycol diacrylate (NPPOGDA), allyl methacrylate (manufactured by Nippon Polyurethane Industry Co., Ltd.) ALMA); Trimethylolpropane triacrylate (TMPTA), trimethylolpropane trimethacrylate (TMPTMA), pentaerythritol triacrylate (PETA), ethoxylated propoxylated trimethylolpropane triacrylate (TMPEOTA) / TMPPOTA), propoxylated glyceryl triacrylate (GPTA) / (GPPOTA), tris (2-hydroxyethyl) isocyanurate triacrylate (THEICTA), pentaerythritol tetraacrylate Pentaerythritol pentaacrylate (DPEPA), and the content of the crosslinked product of the polymerizable oligomer is 10 to 50 parts by weight based on 100 parts by weight of the particles. Oligomers as used herein refer to materials having at least two polymerizable functional groups.

The protective film according to one embodiment can form the single film structure of the particles 13 as shown in Fig. 1C.

As shown in FIG. 1D, the protective film according to another embodiment has a two-layered structure in which two particles 13 are stacked on the lithium electrode 11. On the surface of the particle 13, a coating film 14 containing an ion conductive substance is present similarly to FIG. 1C.

1E, the protective layer 12 may have a multi-layer structure by mixing particles 13a, 13b, and 13c having different sizes. In the case where the protective film 12 has a multilayer structure in which particles 13a, 13b and 13c having different sizes are mixed, the porosity is lowered or the packing density is improved, , Thereby minimizing the lithium metal contact of the electrolyte. It is also possible to suppress the growth of dendrite by increasing the thickness of the protective film.

FIGS. 1F and 1G are diagrams for explaining the effect of the lithium anode according to one embodiment.

1F and 1G, a lithium anode according to an embodiment includes a solid-electrolyte interphase (SEI) formed on a lithium metal electrode 11, a protective film 12 containing particles 13 on the solid- As shown in Fig. The lithium metal electrode 11 and the SEI have soft characteristics due to their thickness and the like, and are pressed by the particles 13. As a result, a groove is formed on the lithium metal electrode 11 and SEI (17 in Fig. 1F, 15b in Fig. 1G).

The step of the groove is, for example, a maximum of ± 1 um. A crosslinked body 14 of a polymerizable oligomer is disposed in a space between the particles 13. The mechanical strength of the protective film 12 can be further increased by the cross-linked body 14 of the polymerizable oligomer.

In Figures 1F and Ig, the particles 13 use crosslinked polystyrene (PS) microspheres, for example. The lithium dendrite growth can be suppressed by the force applied by the particles 13 and guided to form lithium dendrites in the space between the particles 13. [ When the negative electrode using such a protective film is filled, a lithium electrodeposited layer 16 is formed on the lithium metal electrode 11 as shown in FIG. 1g, and SEI (15 of FIG. 1F, And a protective film 12 containing a particle 13 and a crosslinked product 15 of a polymerizable oligomer are laminated on the laminated structure.

When the protective film described above is employed, the lithium electrodeposition density is greatly improved. The dendrite growth is controlled by providing a dendrite growth space by using the network structure and the pore structure, thereby having a function of adsorbing by-products obtained from the anode. Thus, the lithium metal battery employing such a lithium anode has improved lifetime and high temperature stability .

The particles of the protective film may contain, for example, a poly (styrene-divinylbenzene) copolymer.

When the particles are made of a crosslinked polymer, the particles may be chemically linked to each other. Such a chemically connected structure can form a high-strength microsphere network structure.

The porosity of the protective film is 25 to 50%, for example 28 to 48%, for example 30 to 45%. The pore size and porosity of the protective film are determined according to the particle size.

It is possible to form a uniform thickness because there is substantially no aggregation of particles in the protective film according to one embodiment. The thickness of the protective film is 1 to 10 탆, for example, 2 to 9 탆, for example, 3 to 8 탆. The thickness variation of the protective film is 0.1 to 4 탆, for example, 0.1 to 3 탆, for example, 0.1 to 2 탆.

The lithium salt contained in the protective layer is, for example, _{LiSCN, LiN (CN) 2,} LiClO 4, LiBF 4, LiAsF 6, LiPF 6, LiCF 3 SO 3, LiC (CF 3 SO 2) 3, LiN (SO 2 C 2 _{F 5) 2, LiN (SO} 2 CF 3) 2, LiN (SO 2 F) 2, LiSbF 6, LiPF 3 (CF 2 CF 3) 3, LiPF 3 (CF 3) 3, and LiB (C ₂ O ₄ ) _{2. &} Lt; / RTI &gt;

The content of the lithium salt in the protective film is 10 to 70 parts by weight, for example, 15 to 60 parts by weight, for example, 20 to 50 parts by weight, based on 100 parts by weight of the particles. The ionic conductivity of the protective film is excellent when the content of the lithium salt is in the above range.

Examples of the organic solvent include a carbonate compound, a glycol compound, and a dioxolane compound. The carbonate-based compound includes ethylene carbonate, propylene carbonate, dimethyl carbonate, fluoroethylene carbonate, diethyl carbonate, or ethyl methyl carbonate.

The glycine compound may be selected from the group consisting of poly (ethylene glycol) dimethyl ether (PEGDME, polyglyme), tetra (ethylene glycol) dimethyl ether (TEGDME, tetraglyme) Poly (ethylene glycol) monoacrylate (PEGDL), poly (ethylene glycol) monoacrylate, poly (ethylene glycol) (PEGMA) and poly (ethylene glycol) diacrylate (PEGDA).

Examples of dioxolane-based compounds include 1,3-dioxolane, 4,5-diethyl-1,3-dioxolane, 4,5-dimethyl-1,3-dioxolane, , 3-dioxolane, and 4-ethyl-1,3-dioxolane. The organic solvent may be selected from the group consisting of 2,2-dimethoxy-2-phenylacetophenone, dimethyl ether (DME), 1,2-dimethoxyethane, 1,2-diethoxyethane, tetrahydrofuran, gamma butyrolactone, 1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether (1,1,2,2-Tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether).

Examples of the organic solvent include ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, ethylmethyl carbonate, fluoroethylene carbonate, gamma butyrolactone, 1,2-dimethoxyethane, 1,2-diethoxyethane, Dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, polyethylene glycol dimethyl ether, succinonitrile, sulfolane, dimethyl sulfone, ethyl methyl sulfone, diethyl sulfone, adiponitrile, and 1,1 , 2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether, and the like.

In a lithium metal battery employing a negative electrode for a lithium metal battery according to an embodiment, the thickness of the lithium electrodeposited layer deposited on the surface of the charged lithium electrode is 40 占 퐉 or less, the lithium electrodeposited layer is disposed on the negative electrode, Is in the range of 0.2 to 0.5 g / cm ³ , for example, 0.33 to 0.48 g / cm ³ (g / cc).

In a lithium metal battery according to an embodiment, when the lithium negative electrode according to an embodiment of the present invention is applied to a lithium metal battery employing lithium metal, the increase rate of the electrodeposited density of lithium is 50% or more, for example, 50 to 90% to be. Thus, the electrodeposition density is excellent. The electrodeposited density is improved as described above because the lithium negative electrode employs a protective film having high strength. Here, the Young's modulus of the protective film is 10 ⁶ Pa or more at 25 캜, for example, 3 to 6 GPa.

When the Young's modulus of the protective film is in the above range, the function of suppressing the change of the volume of the cathode is excellent, and the attacked part due to the dendrite formed on the surface of the lithium metal electrode is less likely to form a short.

The protective film according to one embodiment has a tensile strength at 25 DEG C of 2.0

MPa or more. The interface resistance between the lithium metal electrode derived from the Nyquist plot obtained from the impedance measurement and the protective film is reduced by 10% or more at 25 DEG C as compared with the bare lithium metal. When the protective film according to one embodiment is used, the interfacial resistance is reduced as compared with the case where only the lithium metal electrode is used, so that the interfacial property is excellent. Also, the cathode has an oxidation current or a reduction current of 0.05 mA / cm ² or less in a voltage range of 0.0 to 6.0 V versus a lithium metal.

Further, when the protective film according to one embodiment is used, there is almost no problem of swelling of the battery after repeated charge and discharge.

The region where the liquid electrolyte directly contacts the lithium metal electrode in the protective film according to one embodiment is 30 to 80% based on the region where the protective film and the lithium metal are in direct contact.

9A to 9C illustrate that the microspheres are disposed on a lithium metal surface in a cathode for a lithium metal battery according to an embodiment.

Referring to this, a micro-sphere 13 having a diameter of 3 탆 is disposed on the lithium metal electrode 11. 9A to 9C, the microspheres 13 are disposed on the upper portion of the lithium metal electrode 11.

9A to 9C, the length of the lithium metal electrode 11 is about 5.4 mu m. And

In Figures 9a, 9b and 9c a is for example about 1.2 탆, 0.9 탆 and 0.5 탆, respectively. In the case where the liquid electrolyte of the protective film is in direct contact with the lithium metal electrode, the regions where the protective film and the lithium metal are in direct contact with each other are about 33.3%, 50%, and 72.2% %to be.

A method of manufacturing a negative electrode for a lithium metal battery according to an embodiment will be described below.

First, the composition for forming a protective film is prepared by mixing the composite particles and the solvent according to one embodiment. The composition for forming a protective film may be coated on the upper portion of the lithium metal electrode and dried to form a protective film, thereby preparing a negative electrode for a lithium metal battery.

As the solvent, tetrahydrofuran, N-methylpyrrolidone and the like can be used. The content of the solvent is 100 to 5000 parts by weight based on 100 parts by weight of the particles.

An ion conductive polymer may be further added to the protective film forming composition.

The composition for forming a protective film may further include at least one selected from an ionic liquid, a polymeric ionic liquid, and a lithium salt.

The above-mentioned coating method can be used as long as it is a commonly available method for forming a protective film. For example, methods such as spin coating, roll coating, curtain coating, extrusion, casting, screen printing, inkjet printing, doctor blading and the like can be used.

Drying is carried out at 20 to 25 ° C. Drying proceeds at a low temperature as described above, so that deformation of the lithium metal electrode does not occur. A protective film having a monodispersed single layer structure can be formed by directly coating a composition for forming a protective film on a lithium metal electrode, thereby significantly improving the film processability. Such a protective film has excellent mechanical strength and improved ionic conductivity.

The drying process may be followed by a rolling process. The rolling process can be carried out under the same process conditions as the conventional battery manufacturing process. The rolling process is performed using, for example, a pressure of 1 to 1.5 kgf / cm ² .

After coating the above protective film forming composition on a lithium metal electrode and drying to form a protective film, a polymerizable oligomer composition obtained by mixing a polymerizable oligomer and a solvent is coated on the coated and dried product, and a crosslinking reaction is carried out The method comprising the steps of: Through such a step, a cross-linked polymerizable oligomer may be contained between the composite particles.

The composite particle used in the production of the protective film forming composition comprises at least one ion conductive material selected from the group consisting of particles and an ion conductive polymer having an ion conductive oligomer and an ion conductive polymer disposed on at least a portion of the particle and having an ion conductive unit Wherein the particles comprise at least one selected from the group consisting of organic particles, inorganic particles and organic-inorganic particles having a size of more than 1 탆 and not more than 100 탆, .

The composite particles can be produced according to the following process.

First, an ion conductive material, particles and a solvent are mixed to obtain a composite particle composition. When the solvent is removed from the composite particle composition, a composite particle having a coating film containing an ion conductive substance on the particle can be produced.

The particles may be microspheres of substantially the same size.

The protective film has an oxidation current or a reduction current of 0.05 mA / cm ² or less in a voltage range of 0.0 to 6.0 V versus lithium metal. The protective film may be electrochemically stable with respect to lithium at a voltage range of 0 V to 6.0 V, for example, a voltage range of 0 V to 5.0 V, specifically, 0 V to 4.0 V. The protective film according to one embodiment can be applied to an electrochemical device operated at a high voltage by having an electrochemically stable wide voltage window.

The particles of the protective film may be organic particles. The organic particles include, for example, polystyrene or poly (styrene-divinylbenzene) copolymers.

The particles of the protective film may be inorganic particles. The above-mentioned inorganic particles include, for example, _{SiO 2, TiO 2, ZnO,} Al 2 O 3, or BaTiO _3.

The particles of the protective film may be organic particles. The organic or inorganic particles are at least one selected from, for example, silsesquioxane having a cage structure and metal-organic framework (MOF).

The silsesquioxane of the cage structure may be, for example, Polyhedral Oligomeric Silsesquioxane (POSS). There are no more than eight silicones present in such POSS, for example six or eight. The silsesquioxane having a cage structure may be a compound represented by the following formula (3).

(3)

_{Si k O 1 .5k (R 1} ) a (R 2) b (R 3) c

In the above formula R ₁ , R ₂ , and R ₃ are independently of each other hydrogen,

A substituted or unsubstituted C1-C30 alkyl group, a substituted or unsubstituted C1-C30 alkoxy group, a substituted or unsubstituted C2-C30 alkenyl group, a substituted or unsubstituted C2-C30 alkynyl group, A substituted or unsubstituted C6-C30 aryl group, a substituted or unsubstituted C6-C30 aryloxy group, a substituted or unsubstituted C2-C30 heteroaryl group, a substituted or unsubstituted C4-C30 carbon ring Group, or a silicon-containing functional group.

In the above formula 3, 0 <a <20, 0 <b <20, 0 <c <20, and k = a + b + c, a, b and c are selected such that the range of k is 6? .

The silsesquioxane of the cage structure may be a compound represented by the following formula (4) or a compound represented by the following formula (5).

 [Chemical Formula 4]

In the general formula (4), R _{1 to} R ₈ independently represent hydrogen, a substituted or unsubstituted C1-C30 alkyl group, a substituted or unsubstituted C1-C30 alkoxy group, a substituted or unsubstituted C2-C30 Substituted or unsubstituted C2-C30 alkynyl group, substituted or unsubstituted C6-C30 aryl group, substituted or unsubstituted C6-C30 aryloxy group, substituted or unsubstituted A C2-C30 heteroaryl group, a substituted or unsubstituted C4-C30 carbon ring group, or a silicon-containing functional group.

 [Chemical Formula 5]

In the formula 5, R ₁ -R ₆ are independently hydrogen, a substituted or unsubstituted C1-C30 alkyl group, a substituted or unsubstituted C1-C30 alkoxy group, a substituted or unsubstituted C2-C30 to each other Substituted or unsubstituted C2-C30 alkynyl group, substituted or unsubstituted C6-C30 aryl group, substituted or unsubstituted C6-C30 aryloxy group, substituted or unsubstituted A C2-C30 heteroaryl group, a substituted or unsubstituted C4-C30 carbon ring group, or a silicon-containing functional group.

According to one embodiment, the silsesquioxane of the cage structure is represented by R ₁ -R ₈ in Chemical Formula 4 and R ₁ -R ₆ in Chemical Formula 5 is an isobutyl group. The silsesquioxane of the cage structure may be, for example, octaisobutyl-t8-silsesquioxane.

The metal-organic skeleton structure is a porous crystalline compound in which element clusters of Groups 2 to 15 or element clusters of Group 2 to Group 15 are formed by chemical bonding with organic ligands.

The organic ligand means an organic group capable of chemical bonding such as coordination bond, ionic bond or covalent bond. For example, the organic ligand is an organic group having two or more sites capable of binding to the metal ion described above, A structure can be formed.

The Group 2 to Group 15 element ions may be selected from the group consisting of cobalt (Co), nickel (Ni), molybdenum (Mo), tungsten (W), ruthenium (Ru), osmium (Os), cadmium (Cd) (Ba), Sr, Fe, Mn, Cr, V, Al, Ti, Zr, Zr, (Pt), copper (Cu), zinc (Zn), magnesium (Mg), hafnium (Hf), Nb, tantalum (Ta), Re, rhodium (Rh), iridium (Ir), palladium , Ag, Sc, Y, In, Thl, Si, Ge, Sn, Pb, As, Sb) and bismuth (Bi), and the organic ligand is at least one selected from aromatic dicarboxylic acid, aromatic tricarboxylic acid, imidazole compound, tetrazole compound, 1,2,3- A sulfonic acid, an aromatic phosphoric acid, an aromatic sulfinic acid, an aromatic phosphinic acid, a bipyridine, an amino group, an imino group, an acyl group, A compound having at least one functional group selected from the group consisting of a methine group, a methane group, a methane group, a methane dithio acid (-CS ₂ H) group, a methane dithioate anion (-CS ₂ ^- ) group, a pyridine group and a pyrazine group.

Examples of the above aromatic dicarboxylic acid or aromatic tricarboxylic acid include benzene dicarboxylic acid, benzenetricarboxylic acid, biphenyldicarboxylic acid and triphenyldicarboxylic acid.

The above-mentioned organic ligands may specifically be a group derived from a compound represented by the following formula (6).

[Chemical Formula 6]

The metal-organic skeleton structure can be, for example, Ti ₈ O ₈ (OH) ₄ [O ₂ CC ₆ H ₄ -CO ₂ ] _6, Cu (bpy) (H ₂ O) ₂ (BF ₄ ) ₂ = 4, 4'-bipyridine}, Zn 4 O (O 2 CC 6 H 4 -CO 2) 3 (Zn-terephthalic acid-MOF, Zn-MOF) or _{Al (OH) {O 2 CC} 6 H 4 -CO ₂ }.

The protective film may be formed of a material selected from the group consisting of i) silsesquioxane having a cage structure, metal-organic framework (MOF), Li _{1 + x + y} Al _x Ti _{2 - x} Si _y P _{3 - y} O ₁₂ (0 <x <2, 0 = y <3), BaTiO ₃ , Pb (Zr _p Ti _1-p ) O ₃ (0 _{? P? 1} ) (PZT), Pb _{1 - x} La _x Zr _{1 - y} Ti _{y O 3 (PLZT) (O≤x} <1, O = y <1), Pb (Mg 1/3 Nb 2/3) O 3 -PbTiO 3 (PMN-PT), HfO 2, SrTiO 3, SnO 2 , CeO ₂ , Na ₂ O, MgO, NiO, CaO, BaO, ZnO, ZrO ₂ , Y ₂ O ₃ , Al ₂ O ₃ , TiO ₂ , SiO ₂ , SiC, Li ₃ PO ₄ , Li _x Ti _{y 4) 3 (0 <x <} 2,0 <y <3), Li x Al y Ti z (PO 4) 3 (0 <x <2, 0 <y <1, 0 <z <3), Li 1 _{x + y +} (Al _p Ga _{1 -p} ) _x (Ti _q Ge _{1 -q} ) _2-x Si _y P _{3 -y} O ₁₂ (O? x? 1, O = _y ? = 1, 1, 0? Z? 1, 0? Y? 1), Li _x La _y TiO ₃ (0 <x <2, 0 <y <3), LixGeyPzSw _{<w <5), Li x} N y (0 <x <4, 0 <y <2), Li x Si y S z (0 <x <3,0 <y <2, 0 <z <4), _{Li x P y S z (0≤x} <3, 0 <y <3, 0 <z <7), Li 2 O, LiF, LiOH, Li 2 CO 3, LiAlO 2, Li 2 O-Al 2 O 3 At least one particle selected from the group consisting of -SiO ₂ -P ₂ O ₅ -TiO ₂ -GeO ₂ , Li _{3 + x} La ₃ M ₂ O ₁₂ (M = Te, Nb, or Zr) A; or ii) the crosslinked body of the particle A. The crosslinked body of the particle A has a structure in which the particle A has a crosslinkable functional group and is crosslinked by these functional groups.

The crosslinkable functional group may be any functional group that can be crosslinked, and examples thereof include an acrylate group, a methacrylate group, and an epoxy group.

When a crosslinkable functional group is present on the particle surface, the particles are covalently linked to each other, and the mechanical strength of the protective layer made of such particles can be further improved.

The ionic liquid refers to a salt in a liquid state or a room-temperature molten salt at room temperature, which has a melting point below room temperature and is composed of only ions. The ionic liquid may be selected from the group consisting of i) an ammonium, pyrrolidinium, pyridinium, pyrimidinium, imidazolium, piperidinium, pyrazolium, oxazolium, pyridazinium, phosphonium, And at least one cation selected from the group consisting of BF ₄ ^- , PF ₆ ^- , AsF ₆ ^- , SbF ₆ ^- , AlCl ₄ ^- , HSO ₄ ^- , ClO ₄ ^- , CH ₃ SO ₃ ^- , CF _{3 ^{CO 2 -, Cl -, Br}} -, I -, SO 4 2-, CF 3 SO 3 -, (FSO 2) 2 N -, (C 2 F 5 SO 2) 2 N -, (C 2 F 5 SO ₂ ) (CF ₃ SO ₂ ) N ^- , and (CF ₃ SO ₂ ) ₂ N ^- .

The ionic liquid includes, for example, N-methyl-N-propylpyrrolidinium bis (trifluoromethanesulfonyl) imide N-butyl-N-methylpyrrolidium bis (fluoromethylsulfonyl) -Butyl-3-methylimidazolium bis (trifluoromethylsulfonyl) amide and 1-ethyl-3-methylimidazolium bis (trifluoromethylsulfonyl) amide.

The content of the ionic liquid is 5 to 40 parts by weight, for example, 7.5 to 30 parts by weight, for example, 10 to 20 parts by weight, based on 100 parts by weight of the particles of the protective film. When the content of the ionic liquid is within the above range, a protective film excellent in ionic conductivity and mechanical properties can be obtained.

(IL / Li) of the ionic liquid (IL) / lithium ion (Li) is 0.1 to 2.0, for example, 0.2 to 1.8, . The protective film having such a molar ratio is excellent in lithium ion mobility and ion conductivity and is excellent in mechanical properties and can effectively suppress the growth of lithium dendrite on the surface of the negative electrode.

The polymeric ionic liquid may be obtained by polymerizing an ionic liquid monomer, or may be a polymeric compound. Such a polymeric ionic liquid has a high solubility in an organic solvent and has an advantage that ionic conductivity can be further improved when added to a protective film.

In the case of obtaining a polymeric ionic liquid by polymerizing the above-mentioned ionic liquid monomer, the polymeric reaction product is washed and dried, and then anion substitution reaction is carried out to obtain an appropriate anion capable of imparting solubility to the organic solvent do.

The polymeric ionic liquid according to one embodiment may be selected from the group consisting of i) ammonium, pyrrolidinium, pyridinium, pyrimidinium, imidazolium, piperidinium, pyrazolium, oxazolium, pyridazinium, At least one cation selected from the group consisting of BF ₄ ^- , PF ₆ ^- , AsF ₆ ^- , SbF ₆ ^- , AlCl ₄ ^- , HSO ₄ ^- , ClO ₄ ^- , CH ₃ SO ₃ ^- , CF ₃ CO ₂ ^- , (CF ₃ SO ₂ ) ₂ N ^- , (FSO ₂ ) ₂ N ^- , Cl ^- , Br ^- , I ^- , SO ₄ ^2- , CF ₃ SO ₃ ^- , _{2 F 5 SO 2) 2 N} -, (C 2 F 5 SO 2) (CF 3 SO 2) N -, NO 3 -, Al 2 Cl 7 -, (CF 3 SO 2) 3 C -, (CF 3 ^{_{) 2 PF 4 -, (CF}} 3) 3 PF 3 -, (CF 3) 4 PF 2 -, (CF 3) 5 PF -, (CF 3) 6 P -, SF 5 CF 2 SO 3 -, SF 5 ^{_{CHFCF 2 SO 3 -, CF 3}} CF 2 (CF 3) 2 CO -, (CF 3 SO 2) 2 CH -, (SF 5) 3 C -, (O (CF 3) 2 C 2 (CF 3) 2 O) ₂ PO ^- . &Lt; ^/ RTI &gt;

According to another embodiment, the polymeric ionic liquid can be prepared by polymerizing an ionic liquid monomer. The ionic liquid monomer has a functional group capable of polymerizing with a vinyl group, an allyl group, an acrylate group, a methacrylate group and the like, and is preferably an ammonium group, a pyrrolidinium group, a pyridinium group, a pyrimidinium group, an imidazolium group, a piperidinium group, The anion may have at least one cation selected from the group consisting of a pyrazolium series, an oxazolium series, a pyridazinium series, a phosphonium series, a sulfonium series, a triazolium series and mixtures thereof.

Examples of the ionic liquid monomer include 1-vinyl-3-ethylimidazolium bromide and a compound represented by the following general formula (7) or (8).

(7)

[Chemical Formula 8]

Examples of the above polymeric ionic liquid include a compound represented by the following formula (9) or a compound represented by the following formula (10).

[Chemical Formula 9]

Wherein R ₁ and R ₃ are independently selected from the group consisting of hydrogen, a substituted or unsubstituted C1-C30 alkyl group, a substituted or unsubstituted C2-C30 alkenyl group, a substituted or unsubstituted C2-C30 A substituted or unsubstituted C6-C30 aryl group, a substituted or unsubstituted C2-C30 heteroaryl group, and a substituted or unsubstituted C4-C30 carbon ring group. In the general formula (9), R ₂ is a chemical bond or represents a C1-C30 alkylene group, a C6-C30 arylene group, a C2-C30 heteroarylene group, or a C4-C30 divalent carbon ring group,

X ^- represents an anion of the ionic liquid,

n is 500 to 2800.

[Chemical formula 10]

In the formula 10 ^Y-X is of formula (9) ^- is defined in the same manner as, n is from 500 to 2800.

Y ^- in formula (10) is, for example, bis (trifluoromethanesulfonyl) imide (TFSI), bis (fluorosulfonyl) imide, BF ₄ ^- or CF ₃ SO ₃ ^- .

Polymeric ionic liquids include, for example, poly (1-vinyl-3-alkylimidazolium), poly (1-allyl-3-alkylimidazolium), poly (1- (methacryloyloxy- and selected from imidazolium) ^{_{cation, CH 3 COO -, CF 3}} COO -, CH 3 SO 3 -, CF 3 SO 3 -, (CF 3 SO 2) 2 N -, (FSO 2) 2 N -, ( ^{_{CF 3 SO 2) 3 C -}} , (CF 3 CF 2 SO 2) 2 N -, C 4 F 9 SO 3 -, C 3 F 7 COO - , and _{(CF 3 SO 2) (CF} 3 CO) N - from Selected anions.

The compound represented by the above formula (10) includes polydiallyldimethylammonium bis (trifluoromethanesulfonyl) imide.

According to another embodiment, the polymeric ionic liquid may comprise a low molecular weight polymer, an ionic liquid and a lithium salt. The low molecular weight polymer may have an ethylene oxide chain. The low molecular weight polymer may be glyme. Examples of the glyme include polyethylene glycol dimethyl ether (polyglyme), tetraethylene glycol dimethyl ether (tetraglyme), and triethylene glycol dimethyl ether (triglyme).

The weight average molecular weight of the low molecular weight polymer is 75 to 2000 Daltons, for example 100 to 1000 Daltons, for example 250 to 500 Daltons. And the thermally stable ionic liquid is as defined in the above ionic liquid. The protective film may further include an oligomer. The oligomer is at least one selected from the group consisting of polyethylene glycol dimethyl ether and polyethylene glycol diethyl ether. The weight average molecular weight of the oligomer is from 200 to 2,000 Daltons, for example from 300 to 1800 Daltons, for example from 400 to 1500 Daltons, and the oligomer content is from 5 to 50 parts by weight, based on 100 parts by weight of the protective film, 10 to 40 parts by weight, for example, 10 to 30 parts by weight. When the oligomer is added in this manner, the film forming property, the mechanical property, and the ionic conductivity of the protective film are superior.

The ionic conductivity of the protective film is preferably 1 X 10 &lt; ^-3 &gt; S / cm or higher at about 25 DEG C,

5 x 10 &lt; ^-3 &gt; S / cm or more.

The composite particle according to another aspect, wherein the composite particle comprises a coating film comprising at least one selected from the group consisting of particles and an ion conductive polymer having an ion conductive oligomer having an ion conductive unit disposed on at least a part of the particle and an ion conductive polymer having an ion conductive unit Wherein the Young's modulus of the electrolyte is not less than 10 ⁶ Pa and the particles have an average particle size of more than 1 탆 and less than 100 탆 of an organic particle, There is provided a composite electrolyte for a lithium metal battery comprising at least one selected from the group consisting of inorganic particles and organic or inorganic particles.

The composite electrolyte contains at least one selected from an ion conductive polymer and an ionic liquid in addition to the composite particles described above.

The ion conductive polymer may be applied to any polymer having ion conductive properties selected from, for example, homopolymers, copolymers and crosslinked polymers commonly used in lithium metal batteries.

As the ion conductive polymer, for example, polyethylene oxide, polypropylene oxide, polyethylene derivatives, poly (ethylene-co-vinyl acetate) and the like are used.

The content of the composite particles in the composite electrolyte is 1 to 100 parts by weight, for example, 1 to 50 parts by weight, for example 5 to 30 parts by weight, based on 100 parts by weight of the ion conductive polymer.

The composite electrolyte may further include at least one selected from a lithium salt and an organic solvent, as in a general electrolyte.

When the composite electrolyte contains a lithium salt, the content of the lithium salt is 1 to 100 parts by weight, for example, 1 to 50 parts by weight, for example 5 to 30 parts by weight, based on 100 parts by weight of the ion conductive polymer.

The ionic liquid, the lithium salt, and the organic solvent can be used as long as they are commonly used in a lithium metal battery.

According to another embodiment, there is provided a lithium metal anode including a cathode, a lithium metal or a lithium metal alloy, and a lithium metal battery interposed therebetween and including the above-described composite electrolyte.

The lithium metal battery according to one embodiment refers to, for example, a lithium air battery, a lithium ion battery, a lithium polymer battery or the like.

The protective film according to one embodiment is suitable as a high-voltage lithium secondary battery protective film.

Here, " high voltage " refers to a case where the charging voltage is in the range of 4.0V to 5.5V.

According to another aspect, there is provided a lithium metal battery including an anode, a cathode for a lithium metal battery according to an embodiment, and an electrolyte interposed therebetween.

The electrolyte may be a complex electrolyte.

The electrolyte may be a mixed electrolyte type including at least one selected from a liquid electrolyte, a solid electrolyte, a gel electrolyte, a polymer ionic liquid, and a solid electrolyte. The lithium metal battery may further include a separator.

One or more selected from a liquid electrolyte, a polymeric ionic liquid, a gel electrolyte, and a solid electrolyte may be interposed between the anode and the electrolyte. The gel electrolyte is an electrolyte having a gel form, and any of those known in the art can be used. The gel electrolyte may contain, for example, a polymer and a polymeric ionic liquid. The polymer may be, for example, a solid graft (block) copolymer electrolyte.

The solid electrolyte can be an organic solid electrolyte or an inorganic solid electrolyte.

Examples of the organic solid electrolyte include a polymer including a polyethylene derivative, a polyethylene oxide derivative, a polypropylene oxide derivative, a phosphate ester polymer, a polyester sulfide, polyvinyl alcohol, polyvinylidene fluoride, and an ionic dissociation group Can be used.

The inorganic solid _{electrolyte, Li 3 N, LiI, Li} 5 NI 2, Li 3 N-LiI-LiOH, Li 2 SiS 3, Li 4 SiO 4, Li 4 SiO 4 -LiI-LiOH, Li 3 PO 4 - _{Li 2 S-SiS 2, Cu} 3 N, LiPON, Li 2 S.GeS 2 .Ga 2 S 3, Li 2 O.11Al 2 O 3, (Na, Li) 1+ x Ti 2 - x Al x (PO ₄ ) ₃ (0.1? _X ? 0.9), Li _{1 + x} Hf _{2 - x} Al _x (PO ₄ ) ₃ (0.1? X? 0.9), Na ₃ Zr ₂ Si ₂ PO ₁₂ , Li ₃ Zr ₂ Si ₂ PO ₁₂ , Na ₅ ZrP ₃ O ₁₂ , Na ₅ TiP ₃ O ₁₂ , Na ₃ Fe ₂ P ₃ O ₁₂ , Na ₄ NbP ₃ O ₁₂ , Na-Silicates, Li _{0 . 3} La _{0 . 5} TiO ₃ , Na ₅ MSi ₄ O ₁₂ (M is a rare earth element such as _{Nd, Gd, Dy) Li 5} ZrP 3 O 12, Li 5 TiP 3 O 12, Li 3 Fe 2 P 3 O 12, Li 4 NbP 3 O 12, Li 1 + x (M, Eu, Gd, Tb, Dy, Ho, Er, Ga) _x (Ge _1-y Ti _y ) _{2 -x} (PO ₄ ) ₃ (x? 0.8, _{0? Y} ? 1.0, M is Nd, Tm or Yb), Li _{1 + x + y} Q _x Ti _{2 - x} Si _y P _{3 - y} O ₁₂ (0 &lt; x? 0.4, 0 &lt; y? 0.6, Q is Al or Ga), Li ₆ BaLa ₂ Ta ₂ O ₁₂ , Li ₇ La ₃ Zr ₂ O ₁₂ , Li ₅ La ₃ Nb ₂ O ₁₂ , Li ₅ La ₃ M ₂ O ₁₂ (M is Nb, Ta), Li _{7 + x} A _x La _{3 - x} Zr ₂ O ₁₂ (0 < x < 3, A is Zn).

The protective film according to one embodiment may include at least one selected from an ionic liquid, a metal salt containing a Group 1 or 2 element and a nitrogen-containing additive, boron nitride, or a mixture thereof.

The metal salt containing the Group 1 element or the Group 2 element is a metal salt containing at least one selected from Cs, Rb, K, Ba, Sr, Ca, Na and Mg, ), An organic nitrate, an inorganic nitrite, an organic nitrite, an organic nitro compound, an organic nitroso compound, an NO compound, and a lithium nitride (Li ₃ N) More than one.

At least one selected from the group consisting of a metal salt containing a group I or II element and a nitrogen-containing additive is insoluble in an organic solvent of a liquid electrolyte. In view of solubility characteristics, when a protective film is used which is stably present only on the surface of a lithium metal anode and is limited in at least one of mobility and a nitrogen-containing additive selected from the group consisting of metal salts containing Group 1 or Group 2 elements, And does not interfere with the movement.

In addition, the metal of the metal salt containing the group 1 or 2 element has a larger atomic size than that of lithium, and if it is contained in the protective layer, the metal containing the group 1 or 2 element due to the steric hindrance effect of the metal The metal salt can inhibit the growth of lithium dendrites on the surface of the lithium metal cathode. The metal cation (for example, Cs or rubidium ion) of the metal salt has a small effective reduction potential as compared with the reduction potential of lithium ion, so that the metal salt is reduced or applied during the lithium deposition process Without process, metal cations form a positive charge electrostatic shield around the initial growth tip of the protuberance on the surface of the lithium metal cathode. When such a positive electrostatic shield is formed, the growth of lithium dendrites on the surface of the lithium metal cathode can be effectively inhibited. As described above, the content of the metal salt is important for the metal salt to have a small effective reduction potential as compared with the reduction potential of lithium. The content of the metal salt is controlled in the range of 0.1 to 100 parts by weight, for example, 1 to 75 parts by weight, for example, 10 to 50 parts by weight, based on 100 parts by weight of the protective film.

In addition, the protective film is excellent in mechanical strength and flexibility, so that the effect of suppressing the formation of lithium dendrite is excellent, and an ion conductive film having high ion conductivity is formed between the lithium metal anode and the protective film. The ion conductive film reduces the interfacial resistance between the lithium metal cathode and the protective film by increasing the ionic conductivity and the lithium ion mobility of the protective film. The ion conductive film contains, for example, lithium nitride (Li ₃ N).

The protective layer chemically improves the electrodeposition process of lithium to improve the electrophoretic morphology of the lithium metal cathode to increase the electrodeposition density on the surface of the lithium metal cathode, Thereby improving mobility. As described above, the ionic liquid, the at least one selected from the group consisting of the metal salt and the nitrogen-containing additive may be localized in the protective film on the surface of the lithium metal negative electrode so that at least one selected from the ionic liquid, metal salt and nitrogen- Or approaches the anode and blocks the reaction with the anode. As a result, it is possible to produce a lithium metal battery with improved rateing performance and life.

The nitrogen containing additive contained in the protective film can be, but not limited to, inorganic nitrate, organic nitrate, inorganic nitrite, organic nitrite, organic nitro compound, organic An organic compound, an organic compound, a nitric compound, an NO compound, and lithium nitride (Li ₃ N).

The inorganic nitrate is at least one selected from the group consisting of lithium nitrate, potassium nitrate, cesium nitrate, barium nitrate and ammonium nitrate, and the organic nitrate is, for example, a dialkyl imidazolium nitride Is at least one selected from the group consisting of guanidine nitrate, ethylnitrite, propylnitrite, butylnitrite, pentylnitrite, and octylnitrite. And the organic nitrite is at least one selected from the group consisting of ethylnitrite, propylnitrite, butylnitrite, pentylnitrite, and octylnitrite.

Examples of the organic nitro compound include at least one selected from the group consisting of nitromethane, nitropropane, nitrobutane, nitrobenzene, dinitrobenzene, nitrotoluene, dinitrotoluene and nitropyridine. And the N-O compound is at least one selected from the group consisting of, for example, pyridine N-oxide, alkylpyridine N-oxide, and tetramethylpiperidine N-oxyl (TEMPO).

In the protective film according to another embodiment, the nitrogen-containing additive is at least one selected from LiNO ₃ and Li ₃ N, and the metal salt containing the group I or II element is cesium bistrifluoromethylsulfonylimide (CsTFSI), and _{CsNO 3, CsPF 6, CsFSI,} CsAsF 6, CsClO 4, or CsBF _4, for example, be CsTFSI.

The content of at least one selected from a metal salt containing a group 1 or group 2 element and a nitrogen-containing additive in the protective film is 0.1 to 100 parts by weight, for example, 0.1 to 30 parts by weight, based on 100 parts by weight of the particles. When the content of at least one selected from the group consisting of metal salts containing Group 1 or Group 2 elements and nitrogen containing additives is within the above range, the effect of inhibiting the growth of lithium dendrites and the effect of reducing the interface resistance between the lithium metal anode surface and the protective film, Can be produced.

According to one embodiment, the protective film may comprise only a metal salt containing a group I or II element. The content of the metal salt containing a Group 1 or Group 2 element is 0.1 to 100 parts by weight, for example, 0.1 to 50 parts by weight, for example, 0.1 to 30 parts by weight, based on 100 parts by weight of the particles.

According to another embodiment, the protective film may contain only a nitrogen-containing additive. At this time, the content of the nitrogen-containing additive is 0.1 to 100 parts by weight, for example, 0.1 to 50 parts by weight, for example, 0.1 to 30 parts by weight, based on 100 parts by weight of the particles.

The protective film may contain, for example, both a metal salt containing a Group 1 or 2 element and a nitrogen-containing additive. The content of the metal salt containing a Group 1 or Group 2 element is 0.01 to 99.99 parts by weight, for example, 0.05 to 50 parts by weight, for example, 0.1 to 30 parts by weight, based on 100 parts by weight of the particles, Is from 0.01 to 99.99 parts by weight, for example, from 0.05 to 50 parts by weight, for example, from 0.1 to 30 parts by weight, based on 100 parts by weight of the particles.

The weight ratio of the metal salt containing the Group 1 or Group 2 element to the nitrogen containing additive in the protective film according to one embodiment is 1: 9 to 9: 1, for example, 1: 2 to 2: 1, specifically 1: 1 . When the mixing ratio by weight of the metal salt containing a Group 1 or Group 2 element and the nitrogen-containing additive is within the above range, the electrodeposition density on the surface of the lithium metal anode and the lithium ion mobility property in the electrolyte are excellent, .

The lithium metal electrode may be lithium metal or a lithium metal alloy, and a liquid electrolyte containing at least one selected from an organic solvent, an ionic liquid and a lithium salt may be further interposed between the lithium metal electrode and the cathode.

When a negative electrode according to an embodiment is employed, a lithium metal battery having improved capacity retention rate can be manufactured. Such a lithium metal battery has high voltage, capacity, and energy density and is widely used in the fields of portable telephones, notebook computers, batteries for power generation facilities such as wind power and solar power, electric vehicles, uninterruptible power supplies, and household batteries.

FIGS. &Lt; RTI ID = 0.0 &gt; 1h-1k &lt; / RTI &gt; schematically illustrate the structure of a lithium metal battery according to one embodiment.

As shown in FIG. 1H, the lithium metal battery has a structure in which an electrolyte 24 is interposed between the positive electrode 21 and the negative electrode 22. A protective film (23) is included between the electrolyte (24) and the cathode (22). The electrolyte (24) may further include at least one selected from a liquid electrolyte, a polymer ionic liquid, a solid electrolyte, and a gel electrolyte. The lithium metal battery may further include a separator.

As the protective film 23 described above is disposed on at least a part of the cathode 22, the cathode surface can be stabilized electrochemically while being mechanically stabilized. Therefore, the formation of dendrites on the surface of the negative electrode during charging and discharging of the lithium metal battery can be suppressed, and the interface stability between the negative electrode and the electrolyte is improved. Therefore, the cycle characteristics of the lithium metal battery can be improved.

The electrolyte 24 may have a two-layer structure in which a liquid electrolyte 24a and a solid electrolyte 24b are sequentially stacked as shown in FIG. Here, the liquid electrolyte may be disposed adjacent to the protective film 23. This lithium metal battery has a stacking order of a negative electrode / a protective film / an electrolyte (liquid electrolyte / solid electrolyte) / an anode.

Referring to FIG. 1J, the lithium metal battery according to one embodiment may use a separator 24c. The separator may be a single layer film made of polyethylene, polypropylene, polyvinylidene fluoride or a combination thereof, or a multilayer film of two or more thereof. The separator may be a polyethylene / polypropylene double layer separator, a polyethylene / polypropylene / polyethylene triple layer separator , A polypropylene / polyethylene / polypropylene three-layer separator, or the like can be used. The separator may further include an electrolyte containing a lithium salt and an organic solvent.

As shown in FIG. 1K, the lithium metal battery according to one embodiment may be arranged with the liquid electrolyte 24a. Here, the composition of the liquid electrolyte, which may be contained in the protective film 23, may be the same as or different from that of the liquid electrolyte.

FIG. 11 is a schematic view of a lithium metal battery structure according to another embodiment.

The lithium metal battery 30 includes a battery case 34 that includes an anode 31, a cathode 32 according to one embodiment, and accommodates them.

In Figs. 1h-l, the anode may be a porous anode. The porous anode includes pores which contain pores or which do not exclude the formation of an anode intentionally so that the liquid electrolyte can be permeated into the inside of the anode by capillary phenomenon or the like.

For example, the porous anode includes a cathode obtained by coating and drying a cathode active material composition comprising a cathode active material, a conductive agent, a binder and a solvent. The thus obtained positive electrode may contain pores existing between the positive electrode active material particles. Such a porous anode may be impregnated with a liquid electrolyte.

According to another embodiment, the anode may comprise a liquid electrolyte, a gel electrolyte, or a solid electrolyte. The liquid electrolyte, the gel electrolyte, and the solid electrolyte can be used as an electrolyte of a lithium metal battery in the related art, and can be any material that does not deteriorate the cathode active material by reacting with the cathode active material during charging and discharging.

The composite electrolyte for a lithium metal battery according to one embodiment is also applicable to a three-dimensional (3D) lithium air battery.

10, the three-dimensional metal-air battery 200 includes a plurality of gas diffusion layers 130a and 130b spaced apart in the thickness direction, and one surface 135a of the plurality of gas diffusion layers 130a and 130b, And a plurality of first anodes 120a and 120c and second anodes 120b and 120d disposed on the other surfaces 137a and 137b opposite to the one surface, 125b, 125c, and 125d of the first and second anodes 120a and 120c and the second anodes 120b and 120d of the cathode 100. The cathode 100 is disposed on the ion- The anode 100 is repeatedly bent 180 degrees in the same pattern as the ion conductive film 110 so as to be in contact with the anode 110 and the cathode 100 is bent 180 degrees between the plurality of gas diffusion layers 130a and 130b adjacent to each other, .

As the ion conductive film 110, a composite electrolyte according to one embodiment may be used.

Since the first anodes 120a and 120c and the second anodes 120b and 120d in the three-dimensional metal-air battery 200 are not disposed on the side surfaces 131a and 131b of the gas diffusion layers 130a and 130b, 110 and the anode 120a, 120b can be prevented from being short-circuited during the cracking of the cathode 100 and the anode 120a, 120b.

A plurality of reinforcing agent-containing intermediate layers 140a, 140b, and 140c disposed in contact with all the bent portions 111 and 112 of the ion conductive film 110 in the three-dimensional metal-air battery 200, respectively. By including the plurality of intermediate layers 140a, 140b and 140c in the three-dimensional metal-air battery 200, it is possible to prevent the cracks of the ion conductive membrane 110 and the short circuit between the cathode 100 and the anodes 120a and 120b have.

The constituent elements constituting the lithium metal battery including the negative electrode according to one embodiment and the method for manufacturing the lithium metal battery having such constituent elements will be described in detail as follows.

The positive electrode active material for producing the positive electrode may include at least one selected from the group consisting of lithium cobalt oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, lithium iron phosphate, and lithium manganese oxide. And any cathode active material available in the art may be used.

For example, Li _a A _{1 - b} B _b D ₂ , where 0.90? A? 1.8, and 0? B? 0.5; Li _a E _{1 -b} B _b O _{2 -c} D _c wherein, in the formula, 0.90? A? 1.8, 0? B? 0.5, 0 _{? C?} 0.05; LiE _{2 - b} B _b O _{4 - c} D _{c where} 0? B? 0.5, 0 _{? C?} 0.05; Li _a Ni _{1 -b- c} Co _b B _c D _? Wherein, in the formula, 0.90 _{? A?} 1.8, 0 _? B _? 0.5, 0 _? C _? 0.05, 0? Li _a Ni _{1 -b- c} Co _b B _c O _{2 - ?} F _? Wherein, in the formula, 0.90? A? 1.8, 0 _? B _? 0.5, 0 _? C _? 0.05, 0 <? Li _a Ni _{1 -b- c} Mn _b B _c D _? Wherein, in the formula, 0.90 _{? A?} 1.8, 0 _? B _? 0.5, 0 _? C _? 0.05, 0? Li _a Ni _{1 -b- c} Mn _b B _c O _{2 - ?} F _? Wherein, in the formula, 0.90? A? 1.8, 0 _? B _? 0.5, 0 _? C _? 0.05, 0? Li _a Ni _b E _c G _d O ₂ wherein 0.90? A? 1.8, 0? B? 0.9, 0? C? 0.5, and 0.001? D? 0.1; Li _a Ni _b Co _c Mn _d GeO ₂ wherein 0.90? A? 1.8, 0? B? 0.9, 0? C? 0.5, 0? D? 0.5, and 0.001? E? 0.1. Li _a NiG _b O ₂ (in the above formula, 0.90? A? 1.8, and 0.001? B? 0.1); Li _a CoG _b O ₂ (in the above formula, 0.90? A? 1.8, 0.001? B? 0.1); Li _a MnG _b O ₂ (in the above formula, 0.90? A? 1.8, and 0.001? B? 0.1); Li _a Mn ₂ G _b O ₄ (in the above formula, 0.90? A? 1.8, 0.001? B? 0.1); QO _2; QS ₂ ; LiQS ₂ ; V ₂ O ₅ ; LiV ₂ O ₅ ; LiIO ₂ ; LiNiVO _4; Li _(3-f) J ₂ (PO ₄ ) ₃ (0 _{? F? 2} ); _{(0≤f≤2) Li (3-f} ) Fe 2 (PO 4) 3; A compound represented by any one of the formulas of LiFePO ₄ can be used.

In the above formula, A is Ni, Co, Mn, or a combination thereof; B is Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, a rare earth element or a combination thereof; D is O, F, S, P, or a combination thereof; E is Co, Mn, or a combination thereof; F is F, S, P, or a combination thereof; G is Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, or combinations thereof; Q is Ti, Mo, Mn, or a combination thereof; I is Cr, V, Fe, Sc, Y, or a combination thereof; J is V, Cr, Mn, Co, Ni, Cu, or a combination thereof.

The cathode active material may be, for example, a compound represented by the following formula (11), a compound represented by the following formula (12), or a compound represented by the following formula (13)

(11)

Li _a Ni _b Co _c Mn _d O ₂

In the above formula (11), 0.90? A? 1.8, 0? B? 0.9, 0? C? 0.5, and 0? D?

[Chemical Formula 12]

Li ₂ MnO ₃

[Chemical Formula 13]

LiMO ₂

In the above formula (13), M is Mn, Fe, Co, or Ni.

The anode is prepared according to the following method.

A cathode active material composition in which a cathode active material, a binder and a solvent are mixed is prepared.

A conductive agent may further be added to the cathode active material composition.

The positive electrode active material composition is directly coated on the metal current collector and dried to produce a positive electrode plate. Alternatively, the cathode active material composition may be cast on a separate support, and then the film peeled from the support may be laminated on the metal current collector to produce a cathode plate.

The binder is a component that assists in bonding between the active material and the conductive agent and bonding to the current collector. Non-limiting examples of such binders include polyvinylidene fluoride, polyvinyl alcohol, carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone, polytetrafluoro And examples thereof include ethylene, polyethylene, polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene butadiene rubber, fluorine rubber and various copolymers. The content thereof is 1 to 50 parts by weight, for example, 2 to 5 parts by weight based on 100 parts by weight of the total weight of the cathode active material. When the content of the binder is in the above range, the binding force of the active material layer to the current collector is good.

The conductive agent is not particularly limited as long as it has electrical conductivity without causing a chemical change in the battery, and examples thereof include graphite such as natural graphite and artificial graphite; Carbonaceous materials such as carbon black, acetylene black, ketjen black, channel black, furnace black, lamp black, and summer black; Conductive fibers such as carbon fiber and metal fiber; Carbon fluoride; Metal powders such as aluminum and nickel powder; Conductive whiskey such as zinc oxide and potassium titanate; Conductive metal oxides such as titanium oxide; And conductive polymers such as polyphenylene derivatives can be used.

The conductive agent is used in an amount of 1 to 10 parts by weight, for example, 2 to 5 parts by weight based on 100 parts by weight of the total weight of the cathode active material. When the content of the conductive agent is in the above range, the conductivity of the finally obtained electrode is excellent.

As a non-limiting example of the solvent, N-methylpyrrolidone or the like is used.

The solvent is used in an amount of 100 to 2000 parts by weight based on 100 parts by weight of the cathode active material. When the content of the solvent is within the above range, the work for forming the active material layer is easy.

The content of the cathode active material, the conductive agent, the binder, and the solvent is a level commonly used in a lithium battery. Depending on the use and configuration of the lithium metal battery, one or more of the conductive agent, the binder and the solvent may be omitted.

The negative electrode may be a lithium metal thin film or a lithium metal alloy thin film as described above.

The lithium metal alloy may comprise lithium and a metal / metalloid capable of alloying with lithium. For example, the metal / metalloid capable of being alloyed with lithium may be at least one selected from the group consisting of Si, Sn, Al, Ge, Pb, Bi, Sb, Si-Y alloy (Y is an alkali metal, an alkali earth metal, (Y is an alkali metal, an alkaline earth metal, a Group 13 to Group 16 element, a transition metal, a rare earth element, or a combination element thereof, Sn is a rare earth element or a combination element thereof, Or the like). The element Y may be at least one element selected from the group consisting of Mg, Ca, Sr, Ba, Ra, Sc, Y, Ti, Zr, Hf, Rf, V, Nb, Ta, Db, Cr, Mo, W, Sg, Pb, Ru, Os, Hs, Rh, Ir, Pd, Pt, Cu, Ag, Au, Zn, Cd, B, Al, Ga, Sn, In, Ge, P, As, Sb, Bi, Te, Po, or a combination thereof.

As the electrolyte, a separator and / or a lithium salt-containing nonaqueous electrolyte conventionally used in a lithium metal battery may be used.

The separator is made of an insulating thin film having high ion permeability and mechanical strength. The pore diameter of the separator is generally 0.01 to 10 mu m and the thickness is generally 5 to 20 mu m. As such a separator, for example, an olefin-based polymer such as polypropylene; A sheet or nonwoven fabric made of glass fiber, polyethylene or the like is used. When a solid polymer electrolyte is used as the electrolyte, the solid polymer electrolyte may also serve as a separator.

Specific examples of the separator may include polyethylene, polypropylene, polyvinylidene fluoride, or a multilayer film of two or more thereof. The separator may be a polyethylene / polypropylene double layer separator, a polyethylene / polypropylene / polyethylene triple layer separator, a polypropylene / / Polypropylene three-layer separator, and the like.

The lithium salt-containing nonaqueous electrolyte is composed of a nonaqueous electrolyte and a lithium salt.

As the non-aqueous electrolyte, a non-aqueous electrolyte, an organic solid electrolyte, or an inorganic solid electrolyte is used.

The nonaqueous electrolytic solution includes an organic oil. These organic solvents may be used as long as they can be used as organic solvents in the art. Examples of the solvent include propylene carbonate, ethylene carbonate, fluoroethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, methyl isopropyl carbonate, dipropyl carbonate, dibutyl carbonate , Fluoroethylene carbonate, benzonitrile, acetonitrile, tetrahydrofuran, 2-methyltetrahydrofuran, gamma -butyrolactone, 1,3-dioxolane, 4-methyldioxolane, N, Amides, N, N-dimethylacetamide, dimethylsulfoxide, dioxane, 1,2-dimethoxyethane, sulfolane, dichloroethane, chlorobenzene, nitrobenzene, diethylene glycol, dimethyl ether or mixtures thereof. And an example wherein the lithium salt is, for _{example, LiPF 6, LiBF 4, LiSbF} 6, LiAsF 6, LiClO 4, LiCF 3 SO 3, Li (CF 3 SO 2) 2 N, Li (FSO 2) 2 N, LiC 4 _{F 9 SO 3, LiAlO 2,} LiAlCl 4, LiN (C x F 2x + 1 SO2) (C y F 2y + 1 SO 2) ( with the proviso that x and y are natural numbers), there is LiCl, LiI and mixtures thereof. For the purpose of improving the charge-discharge characteristics and the flame retardancy, non-aqueous electrolytes include, for example, pyridine, triethylphosphite, triethanolamine, cyclic ether, ethylenediamine, glyme, hexamethylphosphoamide hexamethyl phosphoramide, nitrobenzene derivatives, sulfur, quinone imine dyes, N-substituted oxazolidinones, N, N-substituted imidazolidines, ethylene glycol dialkyl ethers, ammonium salts, pyrroles, 2-methoxyethanol, Etc. may be added. In some cases, a halogen-containing solvent such as carbon tetrachloride or ethylene trifluoride may be further added to impart nonflammability.

The lithium metal battery according to one embodiment can be used not only for a battery cell used as a power source of a small device because of its excellent capacity and life characteristics, but also as a middle- or large-sized battery pack including a plurality of battery cells used as a power source for a medium- The battery module may also be used as a unit battery.

Examples of the medium and large-sized devices include an electric vehicle (EV) including an electric vehicle (EV), a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV) E-bike, an electric motorcycle electric power tool electric power storage device including an electric scooter (E-scooter), but the present invention is not limited thereto.

As used herein, alkyl refers to fully saturated branched or unbranched (or straight chain or linear) hydrocarbons.

Non-limiting examples of "alkyl" include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, n- pentyl, 2,2-dimethylpentyl, 2,3-dimethylpentyl, n-heptyl and the like.

"Alkyl" at least one hydrogen atom of an alkyl group of a halogen atom, halogen-substituted C1-C20 (for _{example: CCF 3, CHCF 2, CH} 2 F, CCl 3 , etc.), an alkoxy of C1-C20 alkoxy, C2-C20 of A carboxyl group or a salt thereof, a sulfonyl group, a sulfamoyl group, a sulfonic acid group or a salt thereof, a phosphoric acid or a salt thereof, or a C1-C4 alkyl group, C20 alkyl group, a C2-C20 alkenyl group, a C2-C20 alkynyl group, a C1-C20 heteroalkyl group, a C6-C20 aryl group, a C6-C20 arylalkyl group, a C6-C20 heteroaryl group, An arylalkyl group, a C6-C20 heteroaryloxy group, or a C6-C20 heteroaryloxyalkyl group.

The term &quot; halogen atom &quot; includes fluorine, bromine, chlorine, iodine and the like.

&Quot; Alkenyl &quot; refers to a branched or unbranched hydrocarbon group having at least one carbon-carbon double bond. Non-limiting examples of the alkenyl group include vinyl, allyl, butenyl, isopropenyl, isobutenyl and the like, and at least one hydrogen atom of the alkenyl may be substituted with the same substituent as the alkyl group described above .

&Quot; Alkynyl &quot; refers to a branched or unbranched hydrocarbon group having at least one carbon-carbon triple bond. Non-limiting examples of the "alkynyl" include ethynyl, butynyl, isobutynyl, propynyl, and the like.

At least one hydrogen atom of &quot; alkynyl &quot; may be substituted with the same substituent as in the alkyl group described above.

&Quot; Aryl " also includes groups wherein the aromatic ring is optionally fused to one or more carbon rings. Non-limiting examples of &quot; aryl &quot; include phenyl, naphthyl, tetrahydronaphthyl, and the like.

Also, at least one hydrogen atom of the &quot; aryl &quot; group may be substituted with the same substituent as the alkyl group described above.

&Quot; Heteroaryl &quot; means a monocyclic or bicyclic aromatic organic group having at least one heteroatom selected from N, O, P, or S, and the remaining ring atoms being carbon. The aryl group may contain, for example, 1 to 5 heteroatoms, and may include 5-10 ring members. The S or N may be oxidized to have various oxidation states.

Examples of heteroaryl include thienyl, furyl, pyrrolyl, imidazolyl, pyrazolyl, thiazolyl, isothiazolyl, 1,2,3-oxadiazolyl, 1,2,4-oxadiazolyl, , 5-oxadiazolyl, 1,3,4-oxadiazolyl group, 1,2,3-thiadiazolyl, 1,2,4-thiadiazolyl, 1,2,5-thiadiazolyl, Thiadiazolyl, isothiazol-3-yl, isothiazol-4-yl, isothiazol-5-yl, oxazol- Yl, isoxazol-3-yl, 1,2,4-triazol-5-yl, Yl, pyrazin-3-yl, pyrazin-2-yl, pyrid-2-yl, Yl, pyrimidin-2-yl, pyrimidin-4-yl, or pyrimidin-5-yl.

The term &quot; heteroaryl &quot; includes those where the heteroaromatic ring is optionally fused to one or more aryl, cyclyaliphatic, or heterocycle.

The &quot; carbon ring &quot; group used in the formula refers to a saturated or partially unsaturated non-aromatic monocyclic, bicyclic or tricyclic hydrocarbon group.

Examples of monocyclic hydrocarbons include cyclopentyl, cyclopentenyl, cyclohexyl, cyclohexenyl, and the like. Examples of bicyclic hydrocarbons are bornyl, decahydronaphthyl, bicyclo [2.1.1] hexyl, bicyclo [2.2.1] heptyl, bicyclo [2.2.1] heptenyl, or bicyclo [2.2.2] octyl. And examples of tricyclic hydrocarbons include adamantly.

&Quot; Heterocycle &quot; may contain from 5 to 20, such as from 5 to 10, carbon atoms as a cyclic group containing at least one heteroatom. Wherein the heteroatom is one selected from sulfur, nitrogen, oxygen and boron.

Alkoxy, aryloxy, heteroaryloxy means alkyl, aryl and heteroaryl, respectively, attached to an oxygen atom herein.

Will be explained in more detail through the following examples and comparative examples. However, the embodiments are for illustrative purposes only and are not intended to be limiting.

Manufacturing example  1: Preparation of composite particles

10 parts by weight of polyethylene glycol (PEG 200, weight average molecular weight: 200) was added to ethanol based on 100 parts by weight of ethanol and then a poly (styrene-b-divinylbenzene) block copolymer (P Microspheres (MS) (average particle diameter: about 3 탆) (EPRUI) were added and mixed to obtain a composite particle composition.

The weight ratio of the polystyrene block to the polydivinylbenzene block in the block copolymer was about 98: 2, and the weight average molecular weight of the poly (styrene-b-divinylbenzene) copolymer was about 100,000 Daltons.

The composite particle composition was subjected to solvent removal using a rotary rotary evaporator to prepare a composite particle in which a coating film containing PEG 200 was disposed on P (S-DVB) MS. The thickness of the coating film containing PEG 200 in the composite particles was about 100 nm, and the content of PEG 200 was about 10 parts by weight based on 100 parts by weight of P (S-DVB) MS.

Manufacturing example  2: Preparation of composite particles

The procedure of Production Example 1 was repeated except that polyethylene glycol (PEG 600, weight average molecular weight: 600) was used instead of polyethylene glycol (PEG 200, weight average molecular weight: 200) . The thickness of the coating film in the composite particles was about 200 nm, and the content of PEG 600 was about 20 parts by weight based on 100 parts by weight of P (S-DVB) MS.

Manufacturing example  3: Preparation of composite particles

The content of PEG 200 was changed to about 3 parts by weight based on 100 parts by weight of P (S-DVB) MS so that the thickness of the coating film in the composite particles was about 50 nm, Composite particles were prepared.

Manufacturing example  4: Preparation of composite particles

The content of PEG 200 was changed to about 30 parts by weight based on 100 parts by weight of P (S-DVB) MS so that the thickness of the coating film was about 200 nm in the composite particles, Composite particles were prepared.

Production Example 5-7: Preparation of composite particles

The procedure of Production Example 1 was repeated except that polysiloxane, poly (oxyethylene) methacrylate and poly (ethylene glycol) diacrylate (PEGDA) were used instead of polyethylene glycol in the preparation of the composite particle composition, Particles were prepared.

Example  1: Manufacture of cathode

The composite particles obtained in Production Example 1 were added to anhydrous tetrahydrofuran to obtain a mixture containing 5% by weight of composite particles.

Lithium bis (fluorosulfonyl) imide (LiFSI) {LiN (SO ₂ F) ₂ } was added to the composite particle-containing mixture to obtain a composition for forming a protective film. Here, the LiFSI content was about 30 parts by weight based on 100 parts by weight of the poly (styrene-b-divinylbenzene) copolymer used in preparing the composite particles.

The composition for forming a protective film was coated on the upper portion of a lithium metal thin film (thickness: about 20 mu m) formed on the copper thin film with a doctor blade to a thickness of about 3 mu m. The coated product was dried at about 25 DEG C and then dried under vacuum at about 40 DEG C for about 24 hours.

Separately, diethylene glycol diacrylate (DEGDA) and 2-hydroxy-2-methylpropiophenone were dissolved in tetrahydrofuran to prepare a 30 wt% solution of DEGDA. The content of DEGDA is 30 parts by weight based on 100 parts by weight of poly (styrene-b-divinylbenzene) block copolymer microspheres, and the content of hydroxy-2-methylpropiophenone is 100 parts by weight based on the total weight of DEGDA solution And 0.7 parts by weight. The solution was cast on top of the dried product. Subsequently, the cast product was dried at about 25 占 폚 for 12 hours and irradiated with UV at about 40 占 폚 for 1 hour to form composite particles (a coating film disposed on the MS and the MS) on the lithium metal thin film, To prepare a negative electrode having a protective film containing a crosslinked product of diethylene glycol diacrylate (DEGDA) disposed in the space. The content of the crosslinked product of diethylene glycol diacrylate (DEGDA) was 20 parts by weight based on 100 parts by weight of the poly (styrene-b-divinylbenzene) block copolymer microspheres. Example 1A: Preparation of composite electrolyte

The composite particles obtained in Production Example 1 were added to anhydrous tetrahydrofuran to obtain a mixture containing 5% by weight of composite particles.

Polyethylene oxide (PEO) was mixed with acetonitrile to obtain a 5 wt% PEO acetonitrile solution. Containing the composite particles in the acetonitrile solution of PEO mixture, lithium bis (sulfonyl fluorophenyl) imide; N- (Lithium bis (fluorosulfonyl) imide LiFSI) {LiN (SO 2 F) 2} , and the ionic liquid-methyl- (N-methyl-N-propyl pyrrolidinium bis (fluorosulfonyl) imide: Pyr 13 FSI) was added to obtain a composition for forming a complex electrolyte.

The content of the poly (styrene-b-divinylbenzene) copolymer in the composition for forming a composite electrolyte is 15 parts by weight based on 100 parts by weight of PEO, the content of LiFSI is 30 parts by weight based on 100 parts by weight of PEO, The content is 40 parts by weight based on 100 parts by weight of PEO.

The composition for forming a composite electrolyte was cast on a substrate, dried at about 40 캜, and the complex electrolyte was separated from the substrate to form a desired composite electrolyte.

Example  2-3: Preparation of cathode

A negative electrode was prepared in the same manner as in Example 1 except that the protective film was changed in thickness so that the thickness of the protective film was changed to about 1 탆 and 8 탆, respectively.

Example  4: Manufacture of cathode

The procedure of Example 1 was repeated except that a poly (acrylonitrile-b-butadiene-b-styrene) block copolymer was further added during the preparation of the protective film forming composition.

The content of the poly (acrylonitrile-b-butadiene-b-styrene) block copolymer was 2 parts by weight based on 100 parts by weight of the poly (styrene-b-divinylbenzene) copolymer used for preparing the composite particles. The weight average molecular weight of the poly (acrylonitrile-b-butadiene-b-styrene) copolymer was about 100,000 Daltons, and the mixing weight ratio of the polyacrylonitrile block, polybutadiene block and polystyrene block was 25:25:50.

Example  5: Manufacture of cathode

The content of the poly (acrylonitrile-b-butadiene-b-styrene) Except that 1 part by weight of poly (styrene-b-divinylbenzene) copolymer was changed to 100 parts by weight based on 100 parts by weight of the poly (styrene-b-divinylbenzene) copolymer.

Example  6-7: Preparation of cathode

Except that the average particle size of poly (styrene-b-divinylbenzene) copolymer microspheres was respectively changed to about 1.3 탆 and 8 탆, respectively.

Example  8: Manufacture of cathode

(Styrene-b-divinylbenzene) copolymer having a weight ratio of 80:20 instead of poly (styrene-b-divinylbenzene) copolymer microspheres having a weight ratio of styrene to divinylbenzene of 98: 2 (49: Copolymer microspheres were used in place of the copolymer microspheres.

Example  9: Manufacture of lithium metal battery

The composition for forming a protective film according to Example 1 was coated on the top of a lithium metal thin film (thickness: about 20 mu m) with a doctor blade to a thickness of about 5 mu m. The coated product was dried at about 25 ° C and then dried under vacuum at about 40 ° C.

Separately, diethylene glycol diacrylate (DEGDA) and 2-hydroxy-2-methylpropiophenone were dissolved in tetrahydrofuran to prepare a 30 wt% solution of DEGDA. The content of DEGDA is 30 parts by weight based on 100 parts by weight of poly (styrene-b-divinylbenzene) block copolymer microspheres, and the content of 2-hydroxy-2-methylpropiophenone is 100 parts by weight Based on about 0.7 parts by weight. The solution was cast on top of the dried product. Subsequently, the cast product was dried at about 25 占 폚 for 12 hours and irradiated with UV at about 40 占 폚 for 1 hour to form composite particles (a coating film disposed on the MS and the MS) on the lithium metal thin film, To prepare a negative electrode having a protective film containing a crosslinked product of diethylene glycol diacrylate (DEGDA) disposed in the space. The content of the crosslinked product of diethylene glycol diacrylate (DEGDA) was 20 parts by weight based on 100 parts by weight of the poly (styrene-b-divinylbenzene) block copolymer microspheres.

Separately, LiNi _{0 . 6} Co _{0 . 2} Al _{0 .} A composition for forming a positive electrode active material layer was obtained by mixing ₂ O ₂ (NCA), a super-P (Timcal Ltd.), polyvinylidene fluoride (PVdF) and N-methylpyrrolidone. In the composition for forming the cathode active material layer, the mixing weight ratio of NCA, the conductive agent and the PVDF was 97: 1.5: 1.5, and the content of N-methylpyrrolidone was NCA When 97 g was used, about 137 g was used.

The composition for forming the cathode active material layer was coated on an aluminum foil (thickness: about 15 탆), dried at 25 캜, and dried. The dried product was vacuum dried at about 110 캜 to prepare a positive electrode.

The obtained positive electrode was immersed in N-methyl-N-propyl pyrrolidium bis (fluorosulfonyl) imide (N-methyl-N-propyl pyrrolidinium bis (fluorosulfonyl) imide: Pyr 13 FSI) Next, a lithium metal battery having a laminated structure shown in FIG. 5 was formed between the positive electrode and the negative electrode (thickness: about 25 μm) through the composite electrolyte prepared according to Example 1A and a polyethylene separator (porosity: about 48% (About 40 mAh pouch cell).

A liquid electrolyte was added between the positive electrode and the lithium metal cathode to produce a lithium metal battery having the laminated structure shown in FIG. As the liquid electrolyte, 1,2-dimethoxyethane (DME) and 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether (1, 1, 2, 2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether: TTE) dissolved in an electrolyte solution of 1.0 M LiN (SO ₂ F) ₂ (hereinafter referred to as LiFSI) was used.

Example  9A: Manufacture of lithium metal battery

A lithium metal battery having the laminated structure shown in Fig. 6 was produced in the same manner as in Example 9, except that a protective film was not formed on the lithium metal thin film (thickness: about 20 mu m). The manufacturing process of the lithium metal battery will be described in more detail as follows.

LiNi _{0 . 6} Co _{0 . 2} Al _{0 .} A composition for forming a positive electrode active material layer was obtained by mixing ₂ O ₂ (NCA), a super-P (Timcal Ltd.), polyvinylidene fluoride (PVdF) and N-methylpyrrolidone. In the composition for forming the cathode active material layer, the mixing weight ratio of NCA, the conductive agent and the PVDF was 97: 1.5: 1.5, and the content of N-methylpyrrolidone was NCA When 97 g was used, about 137 g was used.

The composition for forming the cathode active material layer was coated on an aluminum foil (thickness: about 15 탆), dried at 25 캜, and dried. The dried product was vacuum dried at about 110 캜 to prepare a positive electrode.

The obtained positive electrode was immersed in N-methyl-N-propyl pyrrolidium bis (fluorosulfonyl) imide (N-methyl-N-propyl pyrrolidinium bis (fluorosulfonyl) imide: Pyr 13 FSI) Then, the laminate structure shown in FIG. 6 was formed between the positive electrode and a lithium metal thin film (thickness: about 20 μm) which is a negative electrode, with a composite electrolyte prepared according to Example 1A and a polyethylene separator (porosity: about 48% (About 40 mAh pouch cell) was prepared.

A liquid electrolyte was added between the positive electrode and the lithium metal cathode to produce a lithium metal battery having the laminated structure shown in FIG. As the liquid electrolyte, 1,2-dimethoxyethane (DME) and 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether (1, 1, 2, 2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether: TTE) dissolved in an electrolyte solution of 1.0 M LiN (SO ₂ F) ₂ (hereinafter referred to as LiFSI) was used.

Example  9B: Of the lithium symmetric cell  Produce

The composite particles obtained in Production Example 1 were added to anhydrous tetrahydrofuran to obtain a mixture containing 5% by weight of composite particles.

Polyethylene oxide (PEO) was mixed with acetonitrile to obtain a 5 wt% PEO acetonitrile solution. LiN (SO ₂ F) ₂ } and ionic (lithium) bis (fluorosulfonyl) imide were added to an acetonitrile solution of PEO, (N-methyl-N-propyl pyrrolidinium bis (fluorosulfonyl) imide: Pyr 13 FSI) and triethylene glycol dimethyl ether (G3) To obtain a composition for forming a protective film.

The content of the poly (styrene-b-divinylbenzene) copolymer in the protective film forming composition was 15 parts by weight based on 100 parts by weight of PEO, the content of LiFSI was 30 parts by weight based on 100 parts by weight of PEO, Was 50 parts by weight based on 100 parts by weight of PEO, and the content of G3 was 20 parts by weight based on 100 parts by weight of PEO.

The composition for forming a protective film was cast on a lithium metal thin film (thickness: about 20 mu m) and dried at about 40 DEG C to form a lithium negative electrode.

Between the protective films of the lithium negative electrode, Li _{1 . 4} Al _{0 . 4} Ge _{0 . 2} Ti _{1 .4} (PO ₄₎ to prepare a lithium cell having a symmetrical laminated structure of Figure 8c via the ₃ (LAGTP) electrolyte.

Example  9C: Manufacture of lithium metal battery

LiNi _{0 . 6} Co _{0 . 2} Al _{0 . 2} O ₂ instead A lithium metal battery having the laminated structure shown in Fig. 6 was produced in the same manner as in Example 9, except that LiFePO ₄ was used and a protective film was not formed on the lithium metal thin film (thickness: about 20 탆) Respectively.

Example  10-16: Manufacture of Lithium Metal Battery

A lithium metal battery was produced in the same manner as in Example 9, except that the negative electrode obtained in Examples 2 to 8 was used in place of the negative electrode obtained in Example 1.

Example  17: Manufacture of lithium metal battery

A lithium metal battery was produced in the same manner as in Example 9, except that the electrolyte prepared according to the following procedure was used in place of the composite electrolyte prepared in Example 1A.

(PBR) microspheres (MS) (average particle size: about 3 탆) (EPRUI) were added to anhydrous tetrahydrofuran to prepare a 5% by weight block of poly (styrene-b-divinylbenzene) To obtain a copolymer-containing mixture.

Polyethylene oxide (PEO) was mixed with acetonitrile to obtain an acetonitrile solution of 5 wt% of PEO. LiN (SO ₂ F) ₂ } and an ionic liquid, such as N-methyl (meth) acrylate, were added to an acetonitrile solution of PEO, lithium bis (N-methyl-N-propyl pyrrolidinium bis (fluorosulfonyl) imide: Pyr 13 FSI) was added to obtain a composition for forming an electrolyte.

The content of the poly (styrene-b-divinylbenzene) copolymer in the composition for electrolyte formation was 15 parts by weight based on 100 parts by weight of polyethylene oxide (PEO), and the content of LiFSI was 30 parts by weight based on 100 parts by weight of PEO .

The composition for forming an electrolyte was cast and dried at about 40 DEG C to form an electrolyte.

Example  18: Manufacture of cathode

Except that the average particle diameter of the poly (styrene-b-divinylbenzene) copolymer microspheres was changed to about 50 탆, to prepare a negative electrode.

Example  19: Manufacture of cathode

Instead of a poly (styrene-b-divinylbenzene) copolymer microsphere having a weight ratio of styrene to divinylbenzene of 98: 2, a poly (styrene-b-divinylbenzene) copolymer having a weight ratio of styrene to divinylbenzene of 95: ) Copolymer Microspheres were used in the same manner as in Example 1 to prepare a negative electrode.

Example  20-21: Manufacture of Lithium Metal Battery

A lithium metal battery was produced in the same manner as in Example 9, except that the negative electrodes obtained in Examples 18 and 19 were used in place of the negative electrodes obtained in Example 1, respectively.

Example  22: Preparation of cathode

(Styrene-b-divinylbenzene) copolymer microspheres having an average particle diameter of about 3 占 퐉 and a poly (styrene-b-divinylbenzene) copolymer microsphere having an average particle diameter of about 3 占 퐉 and an about 8 占 퐉 Except that the poly (styrene-b-divinylbenzene) copolymer microsphere was used in a weight ratio of 1: 1.

Example  23: Manufacture of Lithium Metal Battery

(Styrene-b-divinylbenzene) copolymer microspheres having an average particle size of about 3 탆, 3.09 탆, and 2.91 탆, respectively, instead of the poly (styrene-b-divinylbenzene) copolymer microspheres having an average particle size of about 3 탆, (1: 1: 1 weight ratio) was used as a negative electrode, and a lithium metal battery was produced in the same manner as in Example 9 using this negative electrode.

Example  24: Manufacture of lithium metal battery

(Styrene-b-divinylbenzene) copolymer microspheres having an average particle size of about 3 탆, 2.82 탆, and 3.18 탆, respectively, instead of poly (styrene-b-divinylbenzene) copolymer microspheres having an average particle size of about 3 탆, (1: 1: 1 weight ratio) was used as a negative electrode, and a lithium metal battery was produced in the same manner as in Example 9 using this negative electrode.

Example  25: Manufacture of lithium metal battery

(Styrene-b-divinylbenzene) copolymer microspheres having an average particle size of about 3 탆, 2.7 탆 and 3.3 탆, respectively, instead of poly (styrene-b-divinylbenzene) copolymer microspheres having an average particle diameter of about 3 탆, (1: 1: 1 weight ratio) was used as a negative electrode, and a lithium metal battery was produced in the same manner as in Example 9 using this negative electrode.

Example  26: Manufacture of cathode

(Styrene-b-divinylbenzene) copolymer microspheres having an average particle diameter of about 8 占 퐉 and a poly (styrene-b-divinylbenzene) copolymer microsphere having an average particle diameter of about 3 占 퐉 (Styrene-b-divinylbenzene) copolymer microspheres were used in a ratio of 9: 1 by weight.

Example  27: Manufacture of cathode

(Styrene-b-divinylbenzene) copolymer microspheres having an average particle diameter of about 3 占 퐉 and a poly (styrene-b-divinylbenzene) copolymer microsphere having an average particle diameter of about 3 占 퐉 and an average particle diameter of about 1.3 占 퐉 (Styrene-b-divinylbenzene) copolymer microspheres were used in a ratio of 9: 1 by weight.

Example  28: Manufacture of cathode

A negative electrode was prepared in the same manner as in Example 1, except that the composite particles obtained in Production Example 4 were used instead of the composite particles obtained in Production Example 1 in the preparation of the composite particle-containing mixture.

Comparative Example  1: Manufacture of Lithium Metal Battery

LiNi _{0 . 6} Co _{0 . 2} Al _{0 .} A composition for forming a positive electrode active material layer was obtained by mixing ₂ O ₂ (NCA), a super-P (Timcal Ltd.), polyvinylidene fluoride (PVdF) and N-methylpyrrolidone. The mixing weight ratio of LiCoO ₂ , the conductive agent and the PVDF in the composition for forming the positive electrode active material layer was 97: 1.5: 1.5.

The composition for forming the positive electrode active material layer was coated on an aluminum foil (thickness: about 15 탆) and dried at 25 캜. The resultant was then dried under vacuum at about &lt; RTI ID = 0.0 &gt; 110 C &lt; / RTI &gt;

A lithium metal battery was produced through a polyethylene separator (porosity: about 48%) between the anode obtained by the above procedure and a lithium metal anode (thickness: about 20 μm). Here, a liquid electrolyte was added between the positive electrode and the lithium metal negative electrode.

As the liquid electrolyte, 1,2-dimethoxyethane (DME) and 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether (1,1, 2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether: the _{TTE) 1.0M LiN (SO 2 F} ) 2 ( hereinafter, LiFSI mixed solvent) was used as the dissolved electrolyte.

Comparative Example  2: Manufacture of cathode

Polystyrene was added to anhydrous tetrahydrofuran to obtain a 5 wt% polystyrene-containing mixture. The weight average molecular weight of polystyrene was about 100,000 Daltons.

Lithium bis (fluorosulfonyl) imide (LiFSI) {LiN (SO ₂ F) ₂ } was added to the polystyrene-containing mixture to obtain a composition for forming a protective film. Here, the content of LiFSI was about 30 parts by weight based on 100 parts by weight of the polystyrene.

The composition for forming a protective film was coated on the top of a lithium metal thin film (thickness: about 20 mu m) with a doctor blade to a thickness of about 3 mu m.

The coated product was dried at about 25 캜 and then dried under vacuum at about 40 캜 for about 24 hours to prepare a negative electrode having a protective film on the lithium metal thin film.

Comparative Example  3-4: Preparation of cathode

The procedure of Example 1 was repeated except that the average particle size of the poly (styrene-b-divinylbenzene) copolymer microspheres was changed to 1 mu m and 0.2 mu m, respectively, Thereby preparing a negative electrode.

Evaluation example  1: Transmission electron microscopy analysis

The state of the protective film prepared according to Example 1 was analyzed using a transmission electron microscope (TEM). As the TEM analysis, Titan cubed 60-300 manufactured by FEI Co., Ltd. was used as an analyzer, and the results of the analysis are shown in FIGS. 2A to 2C. FIGS. 2A and 2B are TEM photographs of the composite particles contained in the protective film of Example 1, FIG. 2C is a TEM image for comparison with the composite particles of FIGS. 2A and 2B, P (S-DVB) microsphere (MS) ((average particle diameter: about 3 m)).

Referring to this, it can be seen that the composite particles contained in the protective film of Example 1 have a core-shell microsphere structure in which a continuous coating film is formed on the particle surface to a thickness of about 100 nm.

Evaluation example  2: Scanning electron microscope analysis

The state of the surface of the negative electrode prepared according to Example 1 was analyzed using a scanning electron microscope (SEM). The scanning electron microscope (SEM) was a SU-8030 manufactured by Hitachi. An SEM photograph of the cathode prepared according to Example 1 is shown in FIG. 2d.

As a result, it was confirmed that the protective layer was laminated on the surface of the lithium negative electrode, and the composite particles were uniformly aligned and interconnected.

Evaluation example  3: Lithium electrodeposition density  And Electronic scanning microscope  analysis

1) Example 9 and Comparative Example 1

The lithium metal battery produced according to Example 9 and Comparative Example 1 was subjected to constant current charging until the voltage reached 4.40 V (vs. Li) at a current of 0.1 C rate (0.38 mA / cm ² ) at 25 ° C. Followed by a cut-off at a current of 0.05 C rate while maintaining 4.40 V in the constant voltage mode. After one charge, the thickness of the pouch exterior was measured using a lithium micrometer in a lithium metal battery and the results are shown in Table 1 below. The thickness of the lithium electrodeposited layer formed on the cathode was measured, and the results of the electrodeposition density evaluation are shown in Table 1 below.

division Pouch Exterior Thickness Change (㎛) Lithium electrodeposition density
(g / cc) (g / cm 3) Example 9 18-23 0.33-0.36 Comparative Example 1 50-60 0.134-0.161

Referring to Table 1, the lithium metal battery of Example 9 exhibited a small change in the pouch external thickness as compared with the case of Comparative Example 1, and a uniform thickness increase per point was observed. In the lithium metal battery of Example 9, the lithium electrodeposition density was increased as compared with that of Comparative Example 1.

2) High rate characteristic (0.5C)

The lithium metal battery prepared in Example 9 and Comparative Example 1 was subjected to constant current charging for 2 hours until the voltage reached 4.40 V (vs. Li) at a current of 0.5 C rate at 25 DEG C, The morphology of the lithium electrodeposited layer was analyzed using a scanning electron microscope (SEM) analysis of the cross section of the surface of the formed lithium metal anode. SEM photographs of the lithium metal batteries of Example 9 are shown in FIGS. 3A and 3B, and SEM photographs of the lithium metal batteries of Comparative Example 1 are as shown in FIG. 3C and FIG. 3D.

After the above-described one-time charging, the thickness of the pouch exterior was measured using a micrometer in the lithium metal battery. As a result, in the lithium metal battery of Example 9, the pouch exterior thickness variation after 0.5 C charging was about 15 μm, Was small. Also, the electrodeposited density was about 0.4 g / cm ³ or more. On the other hand, the lithium metal battery of Comparative Example 1 showed a thickness change of about 60 탆 and a density of about 0.13 g / cm ³ after the 0.5 C charge.

3) Example 9C

The lithium metal cell produced in accordance with Example 9C was carried out in the same manner as in the lithium metal battery of Example 9, and a voltage of 4.40 V (vs. Li (0.35 mA / cm ² ) at a current of 0.1 C rate ), Followed by cut-off at a current of 0.05 C while maintaining 4.40 V in the constant voltage mode. After one charge, the thickness of the lithium electrodeposited layer formed on the cathode was measured using a lithium micrometer in the lithium metal battery, and the results of the electrodeposition density evaluation are shown in Table 2 below.

division Lithium electro-deposition density (g / cc) (g / cm 3) Example 9C 0.44-0.48

Referring to Table 2, the lithium metal battery of Example 9C was excellent in lithium electrodeposition density.

Evaluation example  4: Charging and discharging  Characteristics (cell life)

1) Examples 9 and 9A

The lithium metal battery prepared in Example 9 and Example 9A was charged at a constant current of 0.1 C rate at 25 DEG C until the voltage reached 4.40 V (vs. Li), and then maintained at 4.40 V in the constant voltage mode And cut off at a current of 0.05 C rate. Then, the discharge was performed at a constant current of 0.1 C rate until the voltage reached 2.8 V (vs. Li) during the discharge (Mars phase, 1 ^st cycle). The charging and discharging process was performed two more times to complete the conversion process.

The lithium metal battery having undergone the above conversion step was charged at a constant current of 0.7 C at a room temperature (25 ° C) until the voltage reached a voltage range of 4.4 V versus lithium metal, and then a cut-off voltage of 2.8 V Lt; RTI ID = 0.0 &gt; of &lt; / RTI &gt;

The charging / discharging process was repeated 299 times, and the charging / discharging process was repeated 300 times in total. The capacity retention ratios are calculated from the following Equation 1, respectively.

[Formula 1]

Capacity retention rate (%) = (100th cycle discharge capacity / 1st cycle discharge capacity) 占 100

The results of the capacity retention rate evaluation are shown in Fig. The MSC in FIG. 4 is for Example 9A, and the MSP + MSC is for Example 9.

Referring to FIG. 4, it can be seen that the lithium metal battery manufactured according to Examples 9 and 9A has a very high capacity retention rate.

Evaluation example  5: Simulation of lithium electrodeposition

Lithium electrodeposition simulations were performed on the cathodes prepared according to Examples 1 and 28 using COMOSOL multiphysics modeling package software. In the negative electrode of Example 1, the thickness of the coating film formed on the surface of the composite particles contained in the protective film was about 100 nm, and the thickness of the coating film formed on the surface of the composite particles contained in the protective film in Example 28 was about 200 nm.

The results of the analysis are shown in Figs. 7A to 7C.

FIG. 7A shows an arrangement of composite particles having a coating film (shell) having a thickness of about 200 nm on the surface of particles (diameter: about 3 μm) on the lithium metal in the cathode of Example 28, and FIGS. 7B and 7C show The results of the lithium electrodeposition simulation analysis are shown in the case where the thickness of the coating film of the composite particles is about 200 nm and 100 nm. 7A, a coating film 74 is disposed on the particles 73 to form composite particles, and a crosslinked body 75 of an oligomer is present between the particles 73. In FIG. 7A, A represents the defect position at which dendrite growth occurs. In FIG. 7B, liion.itot means Li ion, i (current) tot (total), which means total Li ion current density.

In Figure 7b and Figure 7c kappafac denotes the conductivity of the crosslinked form of the conductivity (k _shell / k _oligomer) and k _oligomer is an oligomer (DEGDA) contained in the protective film of the coating conductivity / oligomer, k _shell is of composite particles The conductivity of the coating film is shown. The x-axis represents the distance at which the composite particles are arranged, and the y-axis represents the current density of the protective film.

Referring to FIG. 7B, it can be seen that in the case of kappafac > 25, the current density increases in the region A of FIG. 7A and the current distribution becomes uniform. Referring to FIG. 7C, it can be seen that even when the coating thickness of the composite particle of kappafac> 50 is 100 nm, the current density is uniform and the current density characteristic is high in region A of FIG. 7A.

Evaluation example  6: Interface resistance

1) Example 9C and Comparative Example 1

The lithium metal battery prepared according to Example 9C and the lithium metal battery prepared according to Comparative Example 1 were subjected to a 2-probe method using an impedance analyzer (Solartron 1260A Impedance / Gain-Phase Analyzer) The resistance was measured. The amplitude was ± 10 mV, and the frequency range was 0.1 Hz to 1 MHz.

A Nyguist plot of the impedance measurement results when the elapsed time after the production of the lithium metal battery according to Example 9C and Comparative Example 1 was 24 hours is shown in FIG. In FIG. 8A, the interface resistance between the cathode and the electrolyte is determined by the position and size of the semicircle.

As shown in FIG. 8A, it can be seen that the lithium metal battery manufactured according to Example 9c has an interfacial resistance of 20% or less as compared with Comparative Example 1.

2) Example 9B

The same procedure as in Example 9C and Comparative Example 1 for measuring the interfacial resistance of the lithium symmetric cell produced according to Example 9B was conducted to measure the elapsed time after the production of the lithium metal battery for 24 hours Nyguist plot of the impedance measurement result is shown in FIG. 8B.

Referring to this, it can be seen that the lithium metal battery manufactured according to Example 9B has a small interface resistance between the negative electrode and the electrolyte.

Evaluation example  7: Tensile modulus

1) Example 1 and Comparative Example 2

Tetrahydrofuran (THF) was slowly evaporated in an argon glove box over about 24 hours at about 25 DEG C in the result of casting and casting the composition for forming a protective film according to Example 1 and Comparative Example 2 on a substrate, At 25 DEG C for 24 hours to prepare a film-like protective film. At this time, the thickness of the protective film was about 20 mu m.

The tensile modulus of the protective film was measured using DMA800 (TA Instruments), and the protective film specimen was prepared through ASTM standard D412 (Type V specimens). The tensile modulus is also called Young's modulus.

The deformation of the protective film against stress was measured at a rate of 5 mm per minute at 25 ^° C and a relative humidity of about 30%. The tensile modulus was obtained from the slope of the stress-strain curve.

As a result of the measurement, it was found that the tensile modulus of the protective film prepared according to Example 1 was more than 1 × ^{10 8} Pa and the tensile modulus was improved as compared with the case of Comparative Example 2. Using the protective film prepared according to Example 1 having such characteristics, the volume change of the lithium metal anode and the growth of lithium dendrite can be effectively suppressed.

2) Preparation Example 1

The tensile modulus of the composite particles obtained in Production Example 1 used in the production of the protective film of Example 1 was measured.

As a result of measuring the tensile modulus of elasticity, the tensile modulus of the composite particles obtained according to Production Example 1 was about 3.9 GPa.

Separately, diethylene glycol diacrylate (DEGDA) and initiator 2-hydroxy-2-methylpropiophenone were dissolved in tetrahydrofuran to prepare a 30 wt% solution of DEGDA. This solution was cast on top of a quartz substrate and then the cast product was dried at about 25 DEG C for 12 hours and irradiated with UV at about 40 DEG C for 1 hour to crosslink the diethylene glycol diacrylate (DEGDA) A membrane containing a sieve was prepared.

The tensile modulus of the film containing the crosslinked product of diethylene glycol diacrylate (DEGDA) was about 500 MPa (@ 35 DEG C).

From the above results, it can be seen that the tensile modulus of the protective film containing the composite particles of Example 1 is very excellent.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the exemplary embodiments or constructions. It will be apparent to those skilled in the art that various modifications and variations are possible in light of the above teachings will be. Accordingly, the scope of protection of the present invention should be determined by the appended claims.

10: collector 11: lithium electrode
12: protective film 13: particles
14: ion conductive polymer 15a: composite particle
15b, 17: SEI 16: Lithium electrodeposition layer
21: anode 22: cathode
23: protective film 24: electrolyte
30: lithium metal battery 34: case

Claims (40)

A lithium metal electrode comprising a lithium metal or a lithium metal alloy; And a protective film disposed on at least a portion of the lithium metal electrode,
Wherein the protective film comprises a plurality of composite particles,
The composite particles include particles; And a coating film comprising at least one ion conductive material selected from an ion conductive polymer having an ion conductive oligomer and an ion conductive polymer disposed on at least a portion of the particle and having an ion conductive unit,
Wherein the particles are selected from the group consisting of lithium metal containing at least one selected from organic particles, inorganic particles and organic-inorganic particles having a size of more than 1 탆 and not more than 100 탆. Cathode for batteries. The method according to claim 1,
Wherein the Young's modulus of the protective film is 10 &lt; ⁶ &gt; Pa or more. The method according to claim 1,
The ion-conducting unit is C1-C30 alkylene oxide group, - {Si (R) ( R ') - O-} b - or _{- (CH 2 CH 2 O)} a - {Si (R) (R') - O-} _b -, R and R 'are each independently hydrogen or a C1-C10 alkyl group, and a and b are independently of each other an integer of 1 to 10. The method according to claim 1,
Wherein the ion conductive material is selected from the group consisting of polyethylene glycol, polypropylene glycol, poly (ethylene glycol-co-propylene glycol-co-ethylene glycol), poly (propylene glycol-co-ethylene glycol-co-propylene glycol), polysiloxane, ) Methacrylate, poly (ethylene glycol) diacrylate (PEGDA), poly (propylene glycol) diacrylate, poly (ethylene glycol) dimethacrylate, poly (propylene glycol) dimethacrylate, poly ) Urethane diacrylate, poly (ethylene glycol) urethane dimethacrylate, polyester diacrylate, polyester dimethacrylate, poly (ethylene glycol) urethane triacrylate, poly (ethylene glycol) urethane trimethacrylate Trimethylol propane triacrylate and trimethylol propane trimethacrylate. Poly (ethylene oxide) grafted poly (methyl methacrylate), poly (propylene oxide), poly (ethylene oxide) grafted with at least one member selected from the group consisting of trimethylolpropane triacrylate, trimethylolpropane triacrylate and trimethylolpropane trimethacrylate, Grafted poly (methyl methacrylate), poly (butylene oxide) grafted poly (methyl methacrylate), polysiloxane grafted poly (methyl methacrylate), poly (ethylene glycol) (PEG) grafted Wherein the negative electrode is at least one selected from the group consisting of poly (methyl methacrylate) and poly (propylene glycol) grafted poly (methyl methacrylate). The method according to claim 1,
Wherein the ion conductive material has a weight average molecular weight of 200 to 100,000, The method according to claim 1,
Wherein the thickness of the coating film is 1 占 퐉 or less. The method according to claim 1,
Wherein an amount of the ion conductive material in the coating film is 10 to 50 parts by weight based on 100 parts by weight of the particles. The method according to claim 1,
Wherein the conductivity of the ion conductive material in the coating layer is at least 5 times greater than the conductivity of the material in the remaining region except for the composite particles in the protective layer. The method according to claim 1,
Wherein the protective film further comprises a crosslinked material of a polymerizable oligomer existing between the composite particles. 10. The method of claim 9,
The polymerizable oligomer may be selected from the group consisting of diethylene glycol diacrylate (DEGDA), triethylene glycol diacrylate (TEGDA), tetraethylene glycol diacrylate (TTEGDA), polyethylene glycol diacrylate (PEGDA), dipropylene glycol diacrylate (DPGDA), tripropylene glycol diacrylate (TPGDA), ethoxylated trimethylolpropane triacrylate (ETPTA), acrylate-functionalized ethylene oxide, 1,6 Ethoxylated neopentyl glycol diacrylate (NPEOGDA), propoxylated neopentyl glycol diacrylate (NPPOGDA), allyl methacrylate (manufactured by Nippon Polyurethane Industry Co., Ltd.) ALMA); Trimethylolpropane triacrylate (TMPTA), trimethylolpropane trimethacrylate (TMPTMA), pentaerythritol triacrylate (PETA), ethoxylated propoxylated trimethylolpropane triacrylate (TMPEOTA) / TMPPOTA), propoxylated glyceryl triacrylate (GPTA) / (GPPOTA), tris (2-hydroxyethyl) isocyanurate triacrylate (THEICTA), pentaerythritol tetraacrylate Pentaerythritol pentaacrylate (DPEPA), and at least one member selected from the group consisting of
Wherein the content of the crosslinked product of the polymerizable oligomer is 10 to 50 parts by weight based on 100 parts by weight of the particles. The method according to claim 1,
Wherein the protective film comprises a lithium salt or a liquid electrolyte containing a lithium salt and an organic solvent. The method according to claim 1,
Wherein the particles of the protective film are chemically or physically crosslinked. The method according to claim 1,
Wherein the particles of the protective film comprise at least one selected from the group consisting of polystyrene, a copolymer containing a styrene repeating unit, a copolymer containing a repeating unit having a crosslinkable functional group, and a crosslinked polymer. The method according to claim 1,
The particles of the protective film,
Poly (styrene-divinylbenzene) copolymer, poly (methyl methacrylate-divinylbenzene) copolymer, poly (ethyl methacrylate-divinylbenzene) copolymer, poly (pentylmethacrylate-divinylbenzene) Poly (styrene-ethylene-butylene-styrene) copolymer, poly (butyl methacrylate-divinylbenzene) copolymer, poly (Styrene-acrylonitrile) copolymer, poly (styrene-vinylidene chloride) copolymer, poly (acrylonitrile-butadiene-styrene) Acrylonitrile-butadiene-styrene) copolymers, poly (methyl methacrylate-acrylonitrile-butadiene-styrene) copolymers, (C1-C9 alkyl) methacrylate Butadiene-styrene) copolymers, poly ((C1-C9 alkyl) acrylate-butadiene-styrene) copolymers, - (C1-C9 alkyl) acrylate) copolymers, and crosslinking polymers. The method according to claim 1,
The inorganic particles and the organic particles of the protective film may be selected from the group consisting of i) silsesquioxane having a cage structure, metal-organic framework (MOF), Li _{1 + x + y} Al _x Ti _{2 - x} Si _y P _{3 - y} O ₁₂ (0 <x <2, 0 = y <3), BaTiO ₃ , Pb (Zr _p Ti _1-p ) O ₃ (0 _{? P? 1} ) (PZT), Pb _{1 - x} La _x Zr _{1 - y} Ti _{y O 3 (PLZT) (O≤x} <1, O = y <1), Pb (Mg 1/3 Nb 2/3) O 3 -PbTiO 3 (PMN-PT), HfO 2, SrTiO 3, SnO 2 , CeO ₂ , Na ₂ O, MgO, NiO, CaO, BaO, ZnO, ZrO ₂ , Y ₂ O ₃ , Al ₂ O ₃ , TiO ₂ , SiO ₂ , SiC, Li ₃ PO ₄ , Li _x Ti _{y 4) 3 (0 <x <} 2,0 <y <3), Li x Al y Ti z (PO 4) 3 (0 <x <2, 0 <y <1, 0 <z <3), Li 1 _{x + y +} (Al _p Ga _1-p ) _x (Ti _q Ge _1-q ) _{2 -x} Si _y P _{3 -y} O ₁₂ (O? x? 1, O = _y ? = 1, _{, O≤q≤1), Li x La y} TiO 3 (0 <x <2, 0 <y <3), LixGeyPzSw (0 <x <4, 0 <y <1, 0 <z <1, 0 < _{w <5), Li x N} y (0 <x <4, 0 <y <2), Li x Si y S z (0 <x <3,0 <y <2, 0 <z <4), Li _{x P y S z (0≤x <} 3, 0 <y <3, 0 <z <7), Li 2 O, LiF, LiOH, Li 2 CO 3, LiAlO 2, Li 2 O-Al 2 O 3 - At least one particle A selected from the group consisting of SiO ₂ -P ₂ O ₅ -TiO ₂ -GeO ₂ , Li _{3 + x} La ₃ M ₂ O ₁₂ (M = Te, Nb, or Zr) ; Or ii) a cathode for a lithium metal battery, wherein the particle A is crosslinked. The method according to claim 1,
The organic particles of the protective film may be selected from the group consisting of a poly (styrene-divinylbenzene) copolymer, a poly (methyl methacrylate-divinylbenzene) copolymer, a poly (ethyl methacrylate-divinylbenzene) Poly (butyl methacrylate-divinylbenzene) copolymer, poly (butyl methacrylate-divinylbenzene) copolymer, poly (propyl methacrylate-divinylbenzene) (Styrene-acrylonitrile) copolymer, a poly (styrene-vinylmethacrylate) copolymer, a poly (styrene-methyl methacrylate) copolymer, (C1-C9 alkyl) acrylate-acrylonitrile-butadiene-styrene) copolymers, poly (methyl methacrylate-acrylonitrile-butadiene- Coalescent, poly ((C1-C9 Butadiene-styrene copolymers, poly ((C1-C9 alkyl) acrylate-butadiene-styrene copolymers, poly (styrene- (C1-C9 alkyl) acrylate) copolymers, and poly (acrylonitrile - styrene- (C1-C9 alkyl) acrylate) copolymer. The negative electrode for a lithium metal battery according to claim 1, wherein the block copolymer is a block copolymer. The method according to claim 1,
Wherein the protective film further comprises at least one selected from homopolymers, copolymers and crosslinked polymers having ionic conductivity. 18. The method of claim 17,
Wherein at least one selected from the group consisting of a homopolymer, a copolymer and a crosslinking polymer having ionic conductivity contains a polystyrene or a styrene-based repeating unit. The method according to claim 1,
Wherein the protective film is a single layer or a multilayer film including at least one particle selected from organic particles, inorganic particles and organic-inorganic particles having different sizes. The method according to claim 1,
Wherein the particles are microspheres having an average particle diameter of 1.1 to 50 占 퐉. The method according to claim 1,
The particles include poly (styrene-co-divinylbenzene) copolymer microspheres having an average particle diameter of about 3 占 퐉 and poly (styrene-co-divinylbenzene) copolymer microspheres having an average particle diameter of about 8 占 퐉, Poly (styrene-co-divinylbenzene) copolymer microspheres having a particle diameter of about 3 占 퐉 and poly (styrene-co-divinylbenzene) copolymer microspheres having an average particle diameter of about 1.3 占 퐉, (Styrene-co-divinylbenzene) copolymer microspheres having an average particle size of about 3 mu m and a poly (styrene-co-divinylbenzene) copolymer microsphere having an average particle diameter of about 1.1 mu m. The method according to claim 1,
Wherein the particles of the protective film comprise a crosslinked polymer, and the degree of crosslinking of the crosslinked polymer is 10 to 30%. The method according to claim 1,
Wherein the particles of the protective film are interconnected structures. The method according to claim 1,
The coating film may be a cathode for a lithium metal battery which exists in an independent phase while maintaining a pore structure formed between the particles of the protective film The method according to claim 1,
Wherein the porosity of the protective film is 25 to 50%, and the thickness of the protective film is 1 to 10 탆. The method according to claim 1,
Wherein the protective film further comprises at least one selected from the group consisting of an ionic liquid, a metal salt containing a Group 1 or Group 2 element and a nitrogen-containing additive, boron nitride, or a mixture thereof. 12. The method of claim 11,
The lithium salt _{LiSCN, LiN (CN) 2,} LiClO 4, LiBF 4, LiAsF 6, LiPF 6, LiCF 3 SO 3, LiC (CF 3 SO 2) 3, LiN (SO 2 C 2 F 5) 2, LiN _{(SO 2 CF 3) 2,} LiN (SO 2 F) 2, LiSbF 6, LiPF 3 (CF 2 CF 3) 3, LiPF 3 (CF 3) 3 , and LiB (C ₂ O _{4) 2} at least one selected from a ,
Wherein the organic solvent is selected from the group consisting of ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, ethylmethyl carbonate, fluoroethylene carbonate, gamma butyrolactone, 1,2-dimethoxyethane, 1,2-diethoxyethane, But are not limited to, dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, polyethylene glycol dimethyl ether, succinonitrile, sulfolane, dimethyl sulfone, ethyl methyl sulfone, diethyl sulfone, adiponitrile, And 2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether. A lithium metal battery comprising an anode, a cathode according to any one of claims 1 to 27, and an electrolyte interposed therebetween. 29. The method of claim 28,
A lithium electrodeposited layer is disposed on the cathode, and a lithium electrodeposition density of the lithium electrodeposited layer is 0.2 to 0.5 g / cm &lt; ³ &gt;. 30. The method of claim 29,
Wherein the thickness of the lithium electrodeposited layer is 40 占 퐉 or less. 29. The method of claim 28,
Wherein the electrolyte comprises at least one selected from a liquid electrolyte, a solid electrolyte, a gel electrolyte, and a polymer ionic liquid. 29. The method of claim 28,
Wherein the lithium metal battery comprises a separator. 29. The method of claim 28,
Wherein the lithium metal battery further comprises a separator, wherein the electrolyte is a liquid electrolyte,
Wherein the lithium metal battery has a structure in which a cathode, a separator, a liquid electrolyte and an anode are sequentially stacked. 29. The method of claim 28,
Wherein the electrolyte comprises a composite particle, wherein the composite particle comprises at least one ion conductive material selected from the group consisting of particles and ion conductive polymers having ion conductive oligomers and ion conductive polymers disposed on at least a portion of the particles and having ion conductive units Wherein the particles are selected from organic particles, inorganic particles and orgnic-inorganic particles having a size of more than 1 탆 and not more than 100 탆. And a Young's modulus of the electrolyte is 10 ⁶ Pa or more. 35. The method of claim 34,
Wherein the electrolyte comprises a crosslinked material of a polymerizable oligomer present between the composite particles. Wherein the composite particle comprises at least one ion conductive material selected from the group consisting of particles and ion conductive polymers disposed on at least a portion of the particles and having an ion conductive oligomer having an ion conductive unit and an ion conductive polymer Coating film,
Wherein the particles comprise at least one selected from the group consisting of organic particles, inorganic particles and orgnic-inorganic particles having a size of more than 1 탆 and not more than 100 탆, Composite electrolyte for batteries. 37. The method of claim 36,
Wherein the Young's modulus of the composite electrolyte is 10 &lt; ⁶ &gt; Pa or more. A lithium metal battery comprising a lithium metal anode comprising a cathode, a lithium metal or a lithium metal alloy, and a composite electrolyte interposed therebetween, according to Claim 36. Obtaining a composition for forming a protective film obtained by mixing a composite particle and a solvent; And
27. The negative electrode for a lithium metal battery according to any one of claims 1 to 27, which comprises coating and drying the composition for forming a protective film on a lithium metal electrode to form a protective film, And at least one ion conductive material selected from the group consisting of an ion conductive polymer having an ion conductive unit and an ion conductive polymer having an ion conductive unit and an ion conductive unit disposed in at least a part of the ion conductive unit, A method for manufacturing a negative electrode for a lithium metal battery, the method comprising: at least one of organic particles, inorganic particles, and organic-inorganic particles having a size. 40. The method of claim 39,
After the step of applying the protective film forming composition onto the lithium metal electrode and drying to form a protective film,
Further comprising the step of applying a polymerizable oligomer composition obtained by mixing a polymerizable oligomer and a solvent onto the coated and dried product and performing a crosslinking reaction.

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