KR20180016933A - Positive electrode for metal air battery, metal air battery including the same, and method of preparing the positive electrode for metal air battery - Google Patents

Abstract

Disclosed are a positive electrode for a metal air battery, a metal air battery including the same and a method for preparing a positive electrode for a metal air battery. The positive electrode for a metal air battery comprises: a lithium salt; and a carbon-based material including a polymer electrolyte layer consisting of a polymer electrolyte including one or more hydrophilic materials and hydrophobic materials coated on the surface. Part of the polymer electrolyte can be anchored through a non-covalent bond or a covalent bond on the surface of the carbon-based material. Accordingly, the content of the electrolyte can be minimized. An air metal battery comprising the positive electrode for a metal air battery can improve energy density per unit weight.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a positive electrode for a metal air cell, a metal air cell including the same, and a method for manufacturing the positive electrode for the metal air battery,

An anode for a metal air cell, a metal air cell including the same, and a method for manufacturing the anode for the metal air battery.

BACKGROUND ART Metal air cells, for example, lithium air cells generally include a negative electrode capable of intercalating / deintercalating lithium ions, a positive electrode (air electrode) having oxygen as an active material and undergoing reduction and oxidation of oxygen, It is known that a separator is provided.

The theoretical energy density per unit weight of a lithium air cell is at least 3500 Wh / kg, which is about 10 times that of a lithium ion battery.

Lithium air cells generally include electrolytes to ensure the delivery path of lithium ions. However, the lithium air cell may have a lower energy density per unit weight when it contains an excess amount of electrolyte relative to the carbon-based material of the anode (air electrode).

In order to solve such a problem, there is still a demand for a novel anode for a metal air cell, a metal air cell including the same, and a method for manufacturing the anode for the metal air battery.

The present invention provides a positive electrode for a metal air battery comprising a carbon-based material including a polymer electrolyte layer composed of a polymer electrolyte comprising at least one hydrophilic substance coated on a surface and a hydrophobic substance.

Another aspect is to provide a metal air cell comprising the anode.

Another aspect of the present invention provides a method for manufacturing the positive electrode for a metal air battery.

According to one aspect,

Lithium salts; And

And a polymer electrolyte layer composed of a polymer electrolyte comprising at least one hydrophilic substance coated on the surface and a hydrophobic substance,

Wherein a part of the polymer electrolyte is anchored or covalently bonded to the surface of the carbonaceous material,

According to another aspect,

A negative electrode comprising lithium or a lithium alloy;

The above-described anode; And

And a separator disposed between the cathode and the anode.

According to another aspect,

A polymer electrolyte layer comprising a polymer electrolyte comprising at least one hydrophilic substance and at least one hydrophobic substance coated on the surface of the carbon-based material by adding a carbon-based material, a polymer electrolyte, and a lithium salt to a solvent, A method for manufacturing a positive electrode for a metal air battery, comprising the steps of: preparing a positive electrode;

The positive electrode for a metal air battery according to one aspect includes a carbon-based material including a polymer electrolyte composed of a lithium salt and a polymer electrolyte comprising at least one hydrophilic substance and a hydrophobic substance coated on the surface, A part of the polymer electrolyte is fixed to the surface of the polymer electrolyte membrane by non-covalent bonding or covalent bonding, so that the content of the electrolyte can be minimized. The metal air battery including the anode for the metal air battery can improve the energy density per unit weight.

FIG. 1 is a schematic view showing a cathode structure in which a carbon-based material coated with a polymer electrolyte layer according to an embodiment is arranged.
2 is a schematic view illustrating a method of manufacturing a positive electrode for a metal air battery according to an embodiment.
3 is a schematic view showing a structure of a lithium air battery according to one embodiment.
4A is a TEM image of the carbon-based material coated with the polymer electrolyte layer prepared in Example 1. Fig.
4B and 4C are TEM images of the carbon-based material coated with the polymer electrolyte layer prepared in Example 2. Fig.
5 is a TGA graph of the polymer electrolyte layer of the carbon-based material coated with the polymer electrolyte layer prepared in Example 1. FIG.
6A and 6B are C1s spectrum and O1s spectrum of the XPS analysis of the carbon-based material coated with the polymer electrolyte layer prepared in Example 2, respectively.
FIGS. 7A and 7B are first discharge cycle graphs of a lithium air battery fabricated according to Example 4. FIG.

Hereinafter, a positive electrode for a metallic air cell, a metallic air battery including the positive electrode, and a method for manufacturing the positive electrode for the metallic air battery according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. The following is presented as an example, and the present invention is not limited thereto, and the present invention is only defined by the scope of the following claims.

The term "comprising" is used herein to indicate that it is possible to add and / or intervene other elements, not to exclude other elements unless specifically stated otherwise.

A metal air cell, for example, a lithium air cell, can be composed of a negative electrode capable of intercalating / deintercalating lithium ions, a positive electrode having oxygen as an active material, and an electrolyte capable of transferring lithium ions. Lithium air cells do not need to store oxygen in a lithium air cell, and thus they are attracting attention as a battery having a high theoretical energy density per unit weight.

The lithium air cell can use an aqueous electrolyte and a non-aqueous electrolyte as an electrolyte. However, in the case of using an aqueous electrolyte as an electrolyte, a lithium air cell can cause severe corrosion due to contact between the lithium negative electrode and the aqueous electrolyte. As a result, many researches have been conducted to use a non-aqueous electrolyte as an electrolyte .

As the non-aqueous electrolyte, for example, an ionic liquid or an organic liquid electrolyte may be used. The organic liquid electrolyte may be, for example, a carbonate, ether, sulfone, N, N-dimethysulfoxide (DMSO) or N, N-dimethysulfonamide (DMAC).

When a non-aqueous electrolyte is used as the electrolyte, the following reaction mechanism can be shown.

<Reaction Scheme 1>

4Li + O ₂ ↔ 2Li ₂ O E ^o = 2.91V

₂ Li + O ₂ ↔ Li ₂ O ₂ E ^o = 3.10 V

At the time of discharging, lithium derived from the cathode meets oxygen introduced from the anode (air electrode) to produce lithium oxide and oxygen is reduced (ORR). On the contrary, lithium oxide is reduced during charging and oxygen is oxidized (oxygen evolution reaction: OER). According to Reaction Scheme 1, Li ₂ O ₂ precipitates in the pores of the anode (air electrode) during discharge, and the capacity of the lithium air battery increases as the area of the electrolyte in contact with the anode (air electrode) increases

The anode (air electrode) may comprise a carbon-based material having a high specific surface area and a high pore volume. However, due to the high pore volume, a large amount of electrolyte is used. If the amount of the electrolyte is larger than that of the carbon-based material, an excess amount of the electrolyte is occupied by the space in which the discharge product is generated. As a result, generation of discharge products is disturbed, and the weight of the metal air cell can be increased, and the energy density per unit weight can be lowered.

The positive electrode for a metal air cell according to one embodiment comprises a lithium salt; And a polymer electrolyte layer composed of a polymer electrolyte comprising at least one hydrophilic substance and a hydrophobic substance coated on the surface, wherein a part of the polymer electrolyte is not covalently bonded to the surface of the carbonaceous material, May be anchored to the covalent bond.

The terms "hydrophilic" and "hydrophobic" in this specification can be understood as relative concepts.

As used herein, the terms "hydrophilic" and "hydrophobic" are defined as "hydrophilic properties of a material surface" As used herein, the terms "hydrophilic substance" and "hydrophobic substance" are distinguished based on the wettability of the substance surface with respect to water. The wettability of the material surface to water can be analyzed quantitatively using the contact angle with water.

The "contact angle with water" means the angle formed when the water equilibrates thermodynamically on the material surface. For example, the water contact angle can be obtained by dropping a predetermined volume of water on a substrate coated with a substance and measuring the tangent angle of the line connecting the point of contact of the substance surface with the end of the water solution and the substrate on the substrate . The water contact angle can theoretically be defined by the following Young's Equation:

? _l ? cos ? _Y = ? _s ? - ? _sl (One)

In the above _{(1), γ lν, γ} sν, and γ _sl Respectively represent liquid-gas, solid-gas, and solid-liquid interface tension, and θ _Y represents Contact angle.

The water contact angle can be measured using a telescope-goniometer, a captive bubble method in water, a tilting plate method, a Wilhelmy balance method, a capillary method tube method, a static sessile droplet method, or an ACCU DYNE TEST ^™ kit, all of which can be measured by any measurable method in the art.

The polymer electrolyte may include a hydrophilic substance and a hydrophobic substance having a difference in contact angle with water of 5 ° or more. The water contact angle of the hydrophilic material may be less than 0 [deg.] To 70 [deg.]. The water contact angle of the hydrophobic substance may be 70 ° or more.

The water contact angle is very closely related to the solubility in water. That is, the higher the solubility in water, the lower the contact angle of water, and the lower the solubility in water, the higher the contact angle of water. Therefore, the solubility of hydrophilic substances in water is higher than that of hydrophobic substances.

For example, if the hydrophilic material is polyethylene glycol and the molecular weight is 4000 daltons, dissolution in water at 66% (w / w) at 20 ° C is very good. By comparison, for example, if the hydrophobic material is polypropylene glycol and the molecular weight is 4000 daltons, it is substantially insoluble in water at less than 0.01% (w / w) at 20 ° C. Thus, for example, a polymer composed of polyethylene glycol-polypropylene glycol-polyethylene glycol has a structure in which a polypropylene glycol block of a hydrophobic substance having a low solubility according to the concentration of a polymer in an aqueous solution is mixed with a polyethylene glycol block of a hydrophilic substance having high solubility Is present toward the outside.

The non-covalent bond means a bond based on a weak bond, the bond between the surface of the carbon-based material and the polymer electrolyte. For example, the non-covalent bond may be a hydrogen bond, a Van der Waals bond, a charge transfer, a dipole-dipole interaction, or a pi electron interaction -π stacking interaction). The non-covalent bond may be formed by bonding a polymer electrolyte to the surface of the carbon-based material without inducing defects.

The covalent bond means a bond formed by a reaction between a reactive functional group directly attached to the surface of the carbon-based material and a functional group of the polymer electrolyte. For example, the reactive functional groups directly attached to the surface of the carbon-based material may include "-COOH", "-COH", or "-OH". For example, the covalent bond may be formed using an oxidation reaction, a halogenation reaction, a cycloaddition reaction, a radical addition reaction, or a thiolation reaction. For example, the covalent bond is formed by introducing a reactive functional group such as a carboxyl group (-COOH) into the surface of the carbon-based material through an oxidation reaction by an acid treatment to form an ethylene oxide block having a side chain such as an amino group (-NH ₂ ) (PEO) - b - polypropylene oxide (PPO) - b - polyethylene oxide (PEO) triblock copolymer) of the polymer electrolyte having the polymer electrolyte Bond can be formed.

The term " anchored "as used herein means attached to the surface of the support and that the attached portion is fixed. The portion that does not adhere to the surface of the support may be movable or fixed.

FIG. 1 is a schematic view showing a cathode structure in which a carbon-based material coated with a polymer electrolyte layer according to an embodiment is arranged.

1, the anode is provided with a polymer electrolyte coating layer 2 on the surface of a carbon-based material 1 and a plurality of voids 1 between a plurality of carbon-based materials 1 on which the polymer electrolyte coating layer 2 is disposed. ) Are arranged.

The anode for a metallic air cell according to an embodiment includes a polymer electrolyte coating layer composed of a polymer electrolyte comprising at least one hydrophilic substance and a hydrophobic substance on a surface of a carbonaceous material, thereby minimizing the content of the electrolyte. In addition, since part of the polymer electrolyte can be fixed to the surface of the carbon-based material by non-covalent bonding or covalent bonding, the polymer electrolyte coating layer can be maintained during repetitive charging and discharging of the metal air battery. As a result, the weight of the metal air cell can be reduced and the energy density per unit weight can be improved.

A part or all of the hydrophobic material of the polymer electrolyte may be fixed to the surface of the carbon-based material by non-covalent bonding. Since the surface of the carbon-based material is hydrophobic, the affinity of the polymer electrolyte with the hydrophobic substance is high, so that a part or all of the hydrophobic substance of the polymer electrolyte can be easily fixed to the surface of the carbon-based material.

Some or all of the hydrophobic material of the polymer electrolyte may include a hydrophobic repeating unit and / or a hydrophobic functional group.

The hydrophobic repeating unit may be, for example, a monomer selected from the group consisting of butyl acrylate, 2-ethylhexyl acrylate, methacrylate, benzyl methacrylate, butyl methacrylate, tert-butyl methacrylate, cyclohexyl methacrylate, Hexyl methacrylate, hexyl methacrylate, hexyl methacrylate, isobutyl methacrylate, isopropyl methacrylate, methyl methacrylate, octadecyl methacrylate, tetrahydrofurfuryl methacrylate, acrylonitrile , Maleic anhydride, styrene, propylene glycol, propylene oxide, butene, 1-decene, dicyclopentadiene, isobutylene, 4-methyl-1-pentene, ethylene, propylene, ethylene adipate, ethylene succinate, , 2-ethyl-1,3-hexanediol sebacate, vinyl acetate, vinyl cinnamate, vinyl stearate, tetra Fumaric acid, fumaric acid, fumaric acid, idrofuran, or copolymers thereof.

The hydrophobic functional group may include, for example, a hydroxy group, a methyl group, a carbonyl group, a carboxy group, an amino group, a phosphate group, or a mercapto group.

The hydrophobic repeating unit or / and the hydrophobic functional group may be located in the main chain and / or the side chain of the polymer electrolyte.

Part or all of the hydrophobic substance of the polymer electrolyte of the polymer electrolyte layer may be adsorbed on the surface of the carbon-based material, for example, by van der Waals bonding. Such adsorption does not need to induce defects on the surface of the carbon-based material, and the surface of the carbon-based material can be functionalized while maintaining the inherent properties of the carbon-based material. As a result, the lithium ion conductivity of the metal air cell can be maintained without lowering.

The polymer electrolyte may include a crosslinked polymer electrolyte. The crosslinked polymer electrolyte can more firmly fix the polymer electrolyte coating layer on the surface of the carbon-based material. As a result, the content of the electrolyte can be extremely minimized. As a result, the weight of the metal air cell can be further reduced and the energy density per unit weight can be greatly improved.

The polymer electrolyte of the polymer electrolyte layer may include, for example, a block copolymer composed of a hydrophobic block and a hydrophilic block.

The hydrophobic block is the same as the hydrophobic repeating unit described above.

The hydrophilic block may be, for example, a block copolymer of ethylene glycol, ethylene oxide, N-isopropylacrylamide, 2-oxazoline, 2-ethyl-2-oxazoline, ethyleneimine, sulfopropyl acrylate, 2- Vinyl alcohol, vinyl pyrrolidone, or copolymers thereof, and the like.

The hydrophobic block of the block copolymer may be fixed to the surface of the carbon-based material and the hydrophilic block may be disposed toward the surface of the carbon-based material. For example, a hydrophobic block of the block copolymer is adsorbed on the surface of the carbon-based material by Van der Waals bond, and a hydrophilic block is disposed on the surface of the carbon-based material to allow easy conduction of lithium ions. This form can be seen in Figures 2 and 4b.

For example, the block copolymer may be exemplified by propylene oxide (or propylene glycol) as a hydrophobic block, and ethylene oxide (or ethylene glycol) as a hydrophilic block. This distinction is based on the relative concept as described above.

(Or propylene glycol), which is a hydrophobic block, is adsorbed on the surface of the carbon-based material by Van der Waals bonding, and ethylene oxide (or ethylene glycol) which is a hydrophilic block is adsorbed on the surface of the carbon- . Since, for example, to CH ₂ of the as shown in Scheme 2, a radical claim (radical agent), a UV cross-linked with (or thermal cross-linking) a hydrophilic block of ethylene oxide (or glycol) by such as a UV initiator: CH A polymer electrolyte comprising a crosslinked polyethylene oxide (or polyethylene glycol) and a mostly unmodified polypropylene oxide (or polypropylene glycol) may be formed so as to form a radical.

<Reaction Scheme 2>

The block copolymer may have two or more different polymeric monomer blocks different from each other. For example, the block copolymer may have two or three polymeric monomer blocks different from each other.

The number average molecular weight (Mn) of the hydrophilic block of the block copolymer may be from 500 daltons to 20,000 daltons. For example, the number average molecular weight (Mn) of the hydrophilic block of the block copolymer can be from 500 Daltons to 18,000 Daltons, for example from 500 Daltons to 16,000 Daltons, For example, from 500 Daltons to 14,000 Daltons, such as from 500 Daltons to 12,000 Daltons, such as from 500 Daltons to 10,000 Daltons, for example, , 500 Daltons to 9,000 Daltons, such as 500 Daltons to 8,000 Daltons, such as 500 Daltons to 7,000 Daltons, such as 500 Daltons to 6,000 Daltons, such as 500 Daltons to 5,000 Daltons, such as 600 Daltons to 5,000 Daltons, such as 700 Daltons, Daltons) to 5,000 Daltons, for example 800 Daltons to 5,000 Daltons. When the number average molecular weight (Mn) of the hydrophilic block of the block copolymer is within the above range, the hydrophilic blocks may be dispersed without aggregating and the lithium ion conductivity of the metal air cell including the same may be improved.

The hydrophilic block may be a polymer block having a lithium ion conductive group in its side chain. The lithium ion conductive group exhibits hydrophilicity. Examples of the lithium ion conductive group in the side chain is _{^{-SO 3 -, -COO -, -}} (CF 3 SO 2) 2 N - ( hereinafter ^{'TFSI -'} The _{term), - (FSO 2) 2} N - ( hereinafter ^{'FSI -'} The _{^{term), -SO 2 N - SO 2}} CF 3, -SO 2 N - SO 2 CF 2 CF 3, -SO 2 C 6 H 4 COO-, -C 6 H 3 (SO 2 NH 2 ^{) COO -, -CH (COO -} ) CH 2 COO -, -C 6 H 3 (OH) COO -, -C 6 H 2 (NO 2) 2 COO -, or _{-CH 2 C (CH 3) 2} COO ^{- and} so on.

Polymer block having a lithium ion conductivity in the side chains, for example, TFSI ^- may be functionalized poly anionically methacrylate ^{block-anionic} or ^FSI-anion functionalized polyacrylate block, or TFSI ^- anion or FSI. When such a lithium ion conductive group is present as a side chain, securing the mobility of the lithium ion is easy and the ion conductivity can be improved.

The block copolymer may be a non-crosslinked or crosslinked block copolymer.

For example, the block copolymer is a polyethylene glycol - b - polypropylene glycol di block copolymer, polyethylene oxide - b - polypropylene oxide diblock copolymer, a polystyrene - b - polyethylene glycol di block copolymer, a polystyrene - b - polyethylene oxide diblock copolymer, a polystyrene - b - poly (4-vinylpyridine) diblock copolymer, a polystyrene - b - poly (meth) acrylate diblock copolymer, a polystyrene ^- b -TFSI - functionalized poly anion ( (Meth) acrylate diblock copolymer, polystyrene- b- FSI ^- anion functionalized poly (meth) acrylate diblock copolymer, polyethylene glycol- b -polypropylene glycol- b -polyethylene glycol triblock copolymer, polyethylene oxide - b - polypropylene oxide - b - polyethylene oxide triblock copolymer, polyethylene B -polystyrene- b -polyethylene glycol triblock copolymer, and polyethylene oxide- b -polystyrene- b -polyethylene oxide triblock copolymer.

For example, the block copolymer may be a crosslinked polyethylene glycol- b -polypropylene glycol diblock copolymer, a crosslinked polyethylene oxide- b -polypropylene oxide diblock copolymer, a crosslinked polystyrene- b -polyethylene glycol diblock copolymer copolymer, a polystyrene cross-linked - b - polyethylene oxide diblock copolymer, a polystyrene cross-linked ^- b -TFSI - functionalized with anionic poly (meth) acrylate diblock copolymer, cross-linked polystyrene ^- b -FSI - functionalized with anionic B -polypropylene glycol- b -polyethyleneglycol triblock copolymer, crosslinked polyethylene oxide- b -polypropylene oxide- b -polyethylene oxide triblock copolymer , cross-linked polyethylene glycol - b - polystyrene - b - polyethylene glycol bit Block copolymers, and crosslinked polyethylene oxide - b - polystyrene - b - may comprise at least one member selected from polyethylene oxide triblock copolymer.

For example, the block copolymer may be a crosslinked polyethylene glycol- b -polypropylene glycol diblock copolymer, a crosslinked polyethylene oxide- b -polypropylene oxide diblock copolymer, a crosslinked polystyrene- b -polyethylene glycol diblock copolymer polymer, cross-linked polystyrene - b - polyethylene oxide diblock copolymer, cross-linked polyethylene glycol - b - polypropylene glycol - b - polyethylene glycol triblock copolymer, cross-linked polyethylene oxide - b - polypropylene oxide - b - polyethylene oxide B -polystyrene- b -polyethylene glycol triblock copolymer, and cross-linked polyethylene oxide- b -polystyrene- b -polyethylene oxide triblock copolymer. have.

The number average molecular weight (Mn) of the block copolymer may be from 3,000 Daltons to 60,000 Daltons. For example, the number average molecular weight (Mn) of the block copolymer may be from 3,000 Daltons to 55,000 Daltons, and may be, for example, from 3,000 Daltons to 50,000 Daltons, for example, 3,000 Daltons to 45,000 Daltons, such as 3,000 Daltons to 40,000 Daltons, such as 3,000 Daltons to 35,000 Daltons, such as 3,000 Daltons, For example from 3,000 Daltons to 25,000 Daltons, such as from 3,000 Daltons to 20,000 Daltons, such as from 3,000 Daltons to 20,000 Daltons, For example from 3,500 Daltons to 20,000 Daltons such as from 4,000 Daltons to 20,000 Daltons such as 4,500 Daltons to 20,000 Daltons such as 5,000 Daltons, Daltons to 20,000 Daltons. When the number average molecular weight (Mn) of the block copolymer is within the above range, the elasticity can be maintained without increasing the crystallinity, and the lithium ion conductivity can be improved.

The content of the polymer electrolyte may be 10 parts by weight to 300 parts by weight based on 100 parts by weight of the carbon-based material. With the content of the polymer electrolyte, the metal air cell can secure sufficient lithium ion conductivity and the energy density per unit weight can be improved.

The thickness of the polymer electrolyte layer may be from 1 nanometer (nm) to 30 nanometers (nm). For example, the thickness of the polymer electrolyte layer may be from 1 nanometer (nm) to 28 nanometers (nm), and may range from 1 nanometer (nm) to 26 nanometers (nm) For example from 1 nanometer (nm) to 24 nanometers (nm), for example from 1 nanometer (nm) to 22 nanometers (nm), for example from 1 nanometer (nm) to 20 nanometers For example from 1 nanometer (nm) to 18 nanometers (nm), for example from 1 nanometer (nm) to 16 nanometers (nm), for example from 1 nanometer to 14 nanometers For example, from 1 nanometer (nm) to 12 nanometers (nm), for example, from 1 nanometer (nm) to 10 nanometers (nm). The thickness of the polymer electrolyte layer can be improved within the above range while maintaining the lithium ion conductivity and improving the energy density per unit weight.

The polymer electrolyte layer may be electrochemically stable in the range of 1.4 to 4.5 V charging / discharging voltage with respect to lithium. For example, the polymer electrolyte layer may be electrochemically stable in the range of 1.5 to 4.5 V charge / discharge voltage with respect to lithium.

The carbon-based material may be a porous carbon structure. Some or all of the carbon-based material may be a porous carbon structure. For example, the porous carbon structure may be mesoporous. The carbon-based material has a sufficient specific surface area and can easily transfer electrons from its surface.

For example, the carbon-based material may be selected from the group consisting of carbon nanotubes, carbon nanoparticles, carbon nanofibers, carbon nanosheets, carbon nanorods, carbon nanotubes, graphene, graphene oxide, carbon airgel, inverse opal carbon ), Mixtures thereof, and complexes thereof. For example, the carbon-based material may be carbon nanotubes, carbon nanoparticles, and complexes thereof. These complexes may be, for example, complexes in which particles containing carbon nanoparticles are arranged on the surface of the carbon nanotubes.

For example, the carbon-based material may be carbon nanotubes. The carbon nanotube may be a single wall carbon nanotube (SWCNT), a double wall carbon nanotube (DWCNT), a multi wall carbon nanotube (MWCNT), a rope carbon nanotube, or a combination thereof.

The carbon-based material may be a single wall carbon nanotube (SWCNT), a double wall carbon nanotube (DWCNT), a multiwall carbon nanotube (MWCNT), or a combination thereof.

The average aspect ratio (average length / average diameter) of the carbon nanotubes may be 1 to 20,000. The average aspect ratio can be measured by methods well known to those skilled in the art and can be measured using, for example, transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HR-TEM), SEM, microscope photograph or by using a measuring device using a dynamic light-scattering method. If the average aspect ratio of the carbon nanotubes is within the above range, charge is allowed to be rapidly transferred from the surface to the inside.

The content of the carbon-based material may be, for example, 50 parts by weight to 80 parts by weight based on 100 parts by weight of the anode.

Wherein the lithium salt is selected from the group consisting of LiPF ₆ , LiBF ₄ , LiSbF ₆ , LiAsF ₆ , LiN (SO ₂ C ₂ F ₅ ) ₂ , Li (CF ₃ SO ₂ ) ₂ N, LiC ₄ F ₉ SO ₃ , LiClO ₄ , LiAlO ₂ , _{LiAlCl 4, LiN (C x F} 2x + 1 SO 2) (C y F 2y + 1 SO 2) ( where, x and y are natural numbers), LiF, LiBr, LiCl, LiOH, LiI , and LiB (C ₂ O ₄ ) ₂ (lithium bis (oxalato) borate (LiBOB)). However, it is not limited thereto and can be used as a lithium salt in the technical field.

The content of the lithium salt may be 3 parts by weight to 60 parts by weight based on 100 parts by weight of the positive electrode. Sufficient lithium ion conductivity can be ensured within the range of the lithium salt content.

The molar ratio between the polymer electrolyte monomer of the polymer electrolyte layer and the lithium ion may be 40: 1 to 3: 1. For example, the molar ratio between the polymer electrolyte monomer of the polymer electrolyte layer and the lithium ion may be 20: 1 to 10: 1. However, the molar ratio between the polymer electrolyte monomer and the lithium ion is not limited to the above range, and can be any range as long as it can effectively transfer lithium ions and / or electrons during charging / discharging of the metal air battery.

The anode may be an air electrode.

The metal air cell according to another embodiment may be a lithium air battery. The lithium air battery includes an anode including lithium or a lithium alloy; The above-described anode; And a separator disposed between the cathode and the anode.

3 is a schematic view showing the structure of a lithium air battery 10 according to one embodiment.

3, the lithium air battery 10 includes a positive electrode (air electrode) 15 having oxygen as an active material adjacent to the first current collector 14, lithium or lithium adjacent to the second current collector 12 And a negative electrode (13) containing an alloy is interposed between the separator (16). A lithium ion conductive solid electrolyte membrane (not shown) may be additionally disposed on one surface of the anode (air electrode) 15 facing the separator 16.

The first current collector 14 may also serve as a gas diffusion layer that is porous and capable of diffusing air. A pressing member 19 is disposed on the first current collector 14 so that air can be transmitted to the positive electrode (air electrode). A case 11 made of an insulating resin material is interposed between the anode (air electrode) 15 and the cathode 13 to electrically separate the air electrode and the cathode. The air is supplied to the air inlet 17a and discharged to the air outlet 17b. The lithium air cell 10 can be housed in a stainless steel reactor.

The anode (air electrode) 15 includes a carbon-based material including a lithium salt and a polymer electrolyte layer composed of a polymer electrolyte composed of at least one hydrophilic substance and a hydrophobic substance coated on the surface, A portion of the polymer electrolyte may be anchored or covalently bound.

The lithium salt, the polymer electrolyte, the polymer electrolyte layer, the carbon-based material, and the shape fixed by non-covalent bond or covalent bond are the same as those described above, and the description thereof will be omitted.

The anode (air electrode) 15 may further include an oxygen oxidation / reduction catalyst. The oxygen oxidation / reduction catalyst may be an oxide catalyst such as a noble metal catalyst such as platinum, gold, silver, palladium, ruthenium, rhodium, osmium, manganese oxide, iron oxide, cobalt oxide, nickel oxide, An organometallic catalyst such as phthalocyanine may be used, but it is not limited thereto, and any catalyst that can be used as an oxidation / reduction catalyst for oxygen in the related art is possible.

The anode (air electrode) 15 may further include a binder. The binder may include a thermoplastic resin or a thermosetting resin. For example, it is possible to use polyethylene, polypropylene, polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), styrene-butadiene rubber, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, vinylidene fluoride- Fluorinated vinylidene fluoride copolymer, fluoropropylene copolymer, vinylidene fluoride-chlorotrifluoroethylene copolymer, ethylene-tetrafluoroethylene copolymer, polychlorotrifluoroethylene, vinylidene fluoride-pentafluoropropylene copolymer, propylene-tetrafluoro Ethylene copolymer, ethylene-chlorotrifluoroethylene copolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene copolymer, vinylidene fluoride-perfluoromethyl vinyl ether-tetrafluoroethylene copolymer, or ethylene -Acrylic acid copolymer may be used singly or in combination, but is not limited thereto, Anything that can be used as a binder in the technical field is possible.

The second current collector 12 is not particularly limited as long as it has conductivity. For example, stainless steel, nickel, copper, aluminum, iron, titanium, or carbon. The shape of the second current collector 12 may be, for example, a thin plate, a plate, a mesh or a grid, and may be, for example, a copper foil. The second current collector 12 may be fixed on the case of the Teflon 11b.

The cathode 13 may comprise lithium or a lithium alloy. Optionally, the cathode 13 may comprise a lithium intercalation compound. However, the present invention is not limited thereto, and any material which can be used as the cathode 13 in the related art and includes lithium or can absorb and discharge lithium can be used. Examples of the lithium alloy include aluminum, tin, magnesium, indium, calcium, titanium, or vanadium, and an alloy of lithium. The cathode 13 determines the capacity of the lithium air battery and can be, for example, a lithium thin film.

Optionally, the cathode 13 may also comprise a binder. Examples of the binder include polyvinylidene fluoride (PVdF), polytetrafluoroethylene (PTFE), and the like. The content of the binder is not particularly limited and may be, for example, 30 parts by weight or less based on 100 parts by weight of the total of the negative electrode, and more specifically, 1 to 10 parts by weight based on 100 parts by weight of the negative electrode.

The separator 16 is not limited as long as it can withstand the range of use of the lithium ion battery 10. For example, the separator 16 may be made of a nonwoven fabric made of polypropylene or a nonwoven fabric made of polyphenylene sulfide, a polyethylene or polypropylene Based resin, or a combination of two or more of them may be used.

A lithium ion conductive solid electrolyte membrane may be additionally disposed on the surface of the anode (air electrode) 15 or the cathode 13. For example, the lithium ion conductive solid electrolyte membrane may serve as a protective layer for protecting impurities such as water and oxygen contained in the electrolyte from being directly reacted with lithium contained in the cathode. Examples of the lithium ion conductive solid electrolyte membrane include inorganic materials containing lithium ion conductive glass, lithium ion conductive crystals (ceramic or glass-ceramic), or mixtures thereof, but the lithium ion conductive And can be used in the art as a solid electrolyte membrane capable of protecting the anode (air electrode) 15 or the cathode (13). On the other hand, in consideration of chemical stability, the lithium ion conductive solid electrolyte membrane may be exemplified by an oxide.

For example, as the lithium ion conductive crystal _{Li 1 + x + y (Al} , Ga) x (Ti, Ge) 2 -x Si y P 3-y O 12 ( stage, 0≤x≤1, 0≤y≤ 1, for example, 0? X? 0.4, 0 <y? 0.6, or 0.1? X? 0.3 and 0.1 <y? 0.4). Examples of the lithium ion conductive glass-ceramics include lithium-aluminum-germanium-phosphates (LAGP), lithium-aluminum-titanium-phosphates (LATP), and lithium- aluminum- titanium-silicon phosphates have. The lithium ion conductive solid electrolyte membrane may further contain an inorganic solid electrolyte component as required. Such inorganic solid electrolytes may include, for example, Cu ₃ N, Li ₃ N, LiPON and the like. The lithium ion conductive solid electrolyte film can be used as a single layer or a multilayer film.

The lithium air cell 10 can be manufactured, for example, as follows.

First, the above-described anode (air electrode) 15; An anode (13) comprising lithium or a lithium alloy; And a separator 16 are prepared.

Next, a negative electrode 13 is provided on one side of the case, a separator 16 is provided on the negative electrode 13, and a positive electrode (air electrode) 15 having a lithium ion conductive solid electrolyte membrane is provided on the side opposite to the negative electrode 13 ) Is provided so as to face the cathode (13). Next, a porous current collector is disposed on the anode (air electrode) 15, and air is pressed on the cell by a pressing member 19, which can be transmitted to the anode (air electrode) 15, ) Is completed.

In some cases, a small amount of a liquid electrolyte containing a lithium salt can be injected into the separator provided on the negative electrode at the time of manufacturing the battery. For example, a 1.0 M LiTFSI propylene carbonate electrolyte can be used by impregnating the separator. However, the present invention is not limited thereto and may include a small amount of a lithium salt or an ionic liquid and a lithium salt usable in the art.

For example, the aprotic solvent may be selected from the group consisting of propylene carbonate, ethylene carbonate, fluoroethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, methyl isopropyl carbonate, But are not limited to, propyl carbonate, dibutyl carbonate, fluoroethylene carbonate, benzonitrile, acetonitrile, tetrahydrofuran, 2-methyltetrahydrofuran,? -Butyrolactone, dioxolane, N-dimethylacetamide, N, N-dimethylsulfoxide, dioxane, 1,2-dimethoxyethane, sulfolane, dichloroethane, chlorobenzene, nitrobenzene, diethylene glycol, dimethyl ether or Mixtures thereof, and the like.

For example, the ionic liquid may be selected from the group consisting of diethyldimethyl (2-methoxyethyl) ammonium bis (trifluoromethanesulfonyl) imide (DEME-TFSi, )).

For example, the ionic liquid may be a polymeric ionic liquid. Specific examples of the polymeric ionic liquid include: i) a polymeric ionic liquid such as iodine-based liquid, such as iodine-based liquid, iodine-based liquid, iodine-based liquid, iodine-based liquid, 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 -, Cl -, Br -, I -, BF 4 -, SO 4 -, PF 6 -, ClO 4 -, CF 3 SO 3 -, CF ^{_{3 CO 2 -, (C 2}} F 5 SO 2) 2 N -, (C 2 F 5 SO 2) (CF 3 SO 2) N -, NO 3 -, Al 2 Cl 7 -, AsF 6 -, SbF 6 ^{_{-, CF 3 COO -, CH}} 3 COO -, CF 3 SO 3 -, (CF 3 SO 2) 3 C -, (CF 3 CF 2 SO 2) 2 N -, (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 ^- _{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 - and ( the ^- CF ₃ SO _{2) 2} N It may contain a repeating unit comprising at least one anion selected.

The case may be separated into an upper portion in contact with the cathode and a lower portion in contact with the air electrode, and an insulating resin is interposed between the upper portion and the lower portion to electrically isolate the air electrode and the cathode.

An ion conductive polymer electrolyte may not be additionally contained between the cathode 13 and the anode 15 (air electrode). As a result, the total weight of the lithium air battery is reduced, and the energy density per unit weight can be improved.

The lithium air battery can be used for a lithium primary battery and a lithium secondary battery. The shape is not particularly limited, and examples thereof include a coin shape, a button shape, a sheet shape, a laminate shape, a cylindrical shape, a flat shape, or a horn shape. It can also be applied to large-sized batteries used in electric vehicles and the like.

As used herein, the term "air" is not meant to be limited to atmospheric air, but may include a combination of gases containing oxygen, or pure oxygen gas. This broad definition of the term "air" can be applied to all applications, such as air cells, air bubbles, and the like.

According to another embodiment of the present invention, there is provided a method of manufacturing a positive electrode for a metal air cell, comprising: adding a carbonaceous material, a polymer electrolyte, and a lithium salt to a solvent, and dispersing and drying the same to form at least one hydrophilic material coated on the surface of the carbonaceous material; And a step of preparing the above-described anode including a polymer electrolyte layer composed of a polymer electrolyte composed of a material.

The specific contents of the carbon-based material, the polymer electrolyte, and the lithium salt are the same as those described above, and the description thereof will be omitted.

The solvent is selected from the group consisting of, for example, water, alcohol, acetone, tetrahydrofuran, cyclohexane, carbon tetrachloride, chloroform, methylene chloride, dimethylformamide, dimethylacetamide, dimethylsulfoxide and N-methylpyrrolidone It can be more than a species.

2 is a schematic view illustrating a method of manufacturing a positive electrode for a metal air battery according to an embodiment.

The carbon-based material and the polymer electrolyte are added to the solvent at an appropriate weight ratio to obtain a mixed solution, and then the lithium salt is added and dispersed in an appropriate mole ratio of the polymer electrolyte monomer and lithium ion. Thereafter, the filtration process may be carried out before drying the dispersion. The filtration process may be a filter filtration process having pores of 1 micrometer (mu m) or less. As the filtration process, for example, a PVdF membrane or the like may be used. Through such a process, a carbon-based material containing a lithium salt and a polymer electrolyte coating layer on its surface can be obtained.

The carbon-based material, the polymer electrolyte, and the lithium salt may be added to a solvent, followed by dispersion and drying, followed by a crosslinking process.

The crosslinking process may be a thermal crosslinking process or a UV crosslinking process. If necessary, the thermal crosslinking process may use a crosslinking agent and the UV crosslinking process may use a UV initiator.

As the crosslinking agent, for example, polyhydric alcohols or polyhydric epoxy compounds can be used. Examples of the polyhydric alcohols include aliphatic polyhydric alcohols such as ethylene glycol, glycerin and polyvinyl alcohol; aromatic polyhydric alcohols such as pyrogallol, resorcinol, and hydroquinone; , Aliphatic polyvalent epoxy compounds such as glyceryl polyglycidyl ether and trimethylolpropane polyglycidyl ether, and aromatic polyhydric epoxy compounds such as bisphenol A type epoxy compounds. However, examples of the crosslinking agent are not particularly limited, and the use of crosslinking agents which can be used in the technical field is all possible. The crosslinking density can be easily controlled by using a crosslinking agent and the polymer electrolyte layer can be appropriately anchored on the surface of the carbon-based material.

The content of the crosslinking agent may be, for example, in the range of 1 to 40% by weight based on the total weight of the polymer electrolyte polymerizable monomer.

The thermal crosslinking conditions may be performed under the air atmosphere or in an oxidizing atmosphere at a temperature of about 80 ° C to 120 ° C for 2 hours to 6 hours.

The UV initiator is not particularly limited, but it can be a material that generates free radicals by receiving ultraviolet rays. The UV initiator may be, for example, a UV initiator having a double bond. UV crosslinking may be performed on the lithium salt and the carbon-based material including the polymer electrolyte coating layer on the surface using a UV irradiation apparatus for 20 to 60 minutes.

Thereafter, unreacted crosslinking agent or UV initiator is removed in a vacuum oven to prepare a positive electrode for a metal air cell.

Hereinafter, examples and comparative examples of the present invention will be described. However, the following examples are only illustrative of the present invention, and the present invention is not limited to the following examples.

[Example]

Example  1: polymer The electrolyte layer  Preparation of coated carbon-based materials

Multi-wall carbon nanotube (Hanwha Chemical Manufacturing, CM250, 92 ~ 96%) 50mg of polyethylene glycol - b - polypropylene glycol - b - polyethylene glycol triblock copolymer (Sigma Aldrich Corp., Pluronic P-123, average Mn : 5800 daltons, EO: PO: EO = 20: 70: 20 feed ratio, PEG: 30 wt%) 200 mg of the polymer electrolyte was added to 100 mL of water to obtain a mixed solution.

Lithium trifluoromethanesulfonimide (LiTFSI) powder was added to the mixed solution so that the molar ratio of EO / Li was 20, and the mixture was dispersed for 2 hours with a tip type ultrasonic disperser. Obtaining a PEG- b -PPG- b -PEG triblock copolymer coated with a multi-polymer electrolyte layer consisting of a polyelectrolyte wall carbon nanotubes on the surface of the filtration: the dispersion amount Whatman ^® PVdF film (0.2 ㎛ pore size) Respectively.

The obtained product was dried at room temperature for 12 hours and in a vacuum oven for 12 hours. The dried product was then impregnated with an excess of UV initiator Luperox ^® 104 to perform the UV crosslinking process and the unreacted UV initiator Luperox ^® 104 was removed in a vacuum oven to remove the crosslinked PEG- b- PPG- b- PEG tree A multi - walled carbon nanotube coated with a polymer electrolyte layer composed of a block copolymer polymer electrolyte was prepared.

Example  2: polymer The electrolyte layer  Preparation of coated carbon-based materials

Polyethylene glycol - b - polypropylene glycol - b - polyethylene glycol triblock copolymer (Sigma Aldrich Corp., Pluronic P-123, average Mn : 5800 daltons, EO: PO: EO = 20 : 70: 20 feed ratio, PEG: 30% by weight), a polymer electrolyte instead of the polyethylene glycol - b - polypropylene glycol - b - polyethylene glycol triblock copolymer (Sigma Aldrich Corp., Pluronic F-127, average Mn : 12100 daltons, EO: PO: EO = 101 : 56 : 101 feed ratio, PEG: 73.5 wt%) A multi-walled carbon nanotube coated with a polymer electrolyte layer was prepared in the same manner as in Example 1, except that a polymer electrolyte was used.

Example  3: Lithium Air Battery  making

A separator was disposed on the lithium metal thin film cathode.

0.1 mL of an electrolytic solution prepared by dissolving 1 M LiTFSI (lithium bis (trifluoromethanesulfonyl) imide) in poly (ethylene glycol) -dimethylether (manufactured by Sigma Aldrich, polyethylene glycol dimethyl ether, molecular weight 500 daltons) was injected into the above separator (Celgard 3501).

A lithium-aluminum titanium phosphate (LATP) solid electrolyte (thickness: 250 mu m, Ohara Corp., Japan) solid electrolyte was disposed on the separator.

Then, a polyelectrolyte layer coated with a polymer electrolyte composed of a PEG- b- PPG- b- PEG triblock copolymer polymer electrolyte crosslinked on the surface prepared in Example 1 as an anode (air electrode) was formed on the LATP solid electrolyte The nanotubes were placed. At this time, the polymer electrolyte layer-coated multi-walled carbon nanotubes were 90.5 parts by weight and the lithium salt content was 9.54 parts by weight based on 100 parts by weight of the entire air electrode.

Then, a gas diffusion layer (SGL company, 25BC, gas diffusion layer (GDL)) was attached to the top of the anode, a nickel mesh was placed on the gas diffusion layer, And the cell was fixed to manufacture a lithium air cell

An exemplary structure of the lithium air battery is shown in FIG.

Example  4: Lithium Air Battery  making

Except for using the multi-walled carbon nanotubes coated with the polymer electrolyte layer prepared in Example 2 instead of using the multi-walled carbon nanotubes coated with the polymer electrolyte layer prepared in Example 1 as the anode (air electrode) , And a lithium air cell was fabricated in the same manner as in Example 3.

Comparative Example  One: Lithium Air Battery  making

(1) Production of anode (air electrode)

(Average Mn: 100,000 tons, Aldrich) and LiTFSI as a lithium salt were mixed in an EO / Li molar ratio of 20 to prepare an electrolyte. Then, the electrolyte and the multiwalled carbon nanotube Walled carbon nanotubes were added in a weight ratio of 3: 1 by weight (manufactured by Hanwha Chemical, CM250, 92 to 96%) and mixed again to obtain a positive electrode (air electrode) slurry.

The above-mentioned air electrode slurry was coated on the LATP solid electrolyte membrane (thickness 250 탆, Ohara Corp., Japan) in an amount of 3.248 mg / cm ² (about 1 cm × 1 cm) Thereby preparing an anode (air electrode).

(2) Production of lithium air cell

The same procedure as in Example 3 was carried out except that (1) the positive electrode (air electrode) was used instead of the multi-walled carbon nanotubes coated with the polymer electrolyte layer prepared in Example 1 as the positive electrode (air electrode) A battery was produced.

Analysis example  1: TEM analysis - Mallopoulos  analysis

TEM analysis was performed on the carbon-based material coated with the polymer electrolyte layer prepared in Example 1 and Example 2. [ TEM analysis was performed using a Titan Cubed G2 60-300 manufactured by FEI. The results are shown in Figs. 4A to 4C, respectively.

FIGS. 4A and 4C are images of the carbon-based material coated with the polymer electrolyte layer prepared in Example 1 and Example 2, and FIG. 4B is an image of the carbon-based material coated with the polymer electrolyte layer prepared in Example 2 to be.

4A and 4C, the carbon-based material coated with the polymer electrolyte layer prepared in Example 1 and Example 2 has a polymer electrolyte layer having a thickness of about 2 nm and a thickness of about 5-10 nm Display) is formed on the substrate.

Referring to FIG. 4B, the carbon-based material coated with the polymer electrolyte layer prepared in Example 2 has an anchored part or a covalent bond of a part of the polymer electrolyte of the polymer electrolyte layer, .

Analysis example  2: TGA analysis - Analysis of mass reduction rate of polymer electrolyte

The polymer electrolyte layer of the polymer electrolyte layer coated with the polymer electrolyte layer prepared in Example 1 was subjected to TGA analysis to confirm the polymer electrolyte of the polymer electrolyte layer.

The TGA analysis was performed by heating 10 mg of the carbon-based material sample from 0 ° C to 800 ° C at a heating rate of 10 ° C / min in a nitrogen gas atmosphere with a TGA measuring instrument (TA Instruments, TA Q5000) Weight loss was measured. The results are shown in Fig.

Referring to FIG. 5, the mass of the polymer electrolyte began to decrease at about 330, and the mass reduction was stopped at about 400. The mass reduction rate of the polymer electrolyte is about 45.5%.

Analysis example  3: XPS analysis - Polymers on the surface of carbon-based materials Electrolyte layer  analysis

XPS analysis of the carbon-based material coated with the polymer electrolyte layer prepared in Example 2 confirmed the polymer electrolyte of the polymer electrolyte layer. The results are shown in Figs. 6A and 6B.

XPS analysis was performed by using an XPS measurement apparatus (X-ray Photoelectron Spectroscopy, PHI, Versaprobe).

Referring to FIG. 6A, it can be seen that the C-O bonds observed in the polymer electrolyte and the C-C and C═C bonds observed in the polymer electrolyte and the carbon-based material are observed on the surface of the carbon-based material. It is observed that the size of the peak corresponding to the C-O bond decreases when the surface of the carbon-based material is pulverized and observed after sputtering for 2 minutes.

Referring to FIG. 6B, it can be seen that the peak corresponding to the C-O bond decreases in size after sputtering for 2 minutes. From this, it can be confirmed that the polymer electrolyte exists on the surface of the carbon-based material.

Evaluation example  One: Charging and discharging  Character rating - Energy density evaluation

The lithium air cells fabricated in Example 3 and Comparative Example 1 were discharged to 2.0 V (vs. Li) at a constant current of 0.048 mA / cm ^{2 in} an oxygen atmosphere at 60 ° C. and 1 atm, and then charged to 4.3 V with the same current , And a charge / discharge cycle in which the charge current was charged to 0.0048 mA / cm ² was performed. Part of the charge and discharge test results in the first cycle are shown in Table 1 and Fig. 7A.

The lithium air cells fabricated in Example 4 and Comparative Example 1 were discharged to 1.5 V (vs. Li) at a constant current of 0.048 mA / cm ^{2 in} an oxygen atmosphere at 60 ° C and 1 atm, and then charged to 4.0 V with the same current Thereafter, a charge-discharge cycle was performed in which the charge current was charged to 0.0048 mA / cm ² . Part of the charge and discharge test results in the first cycle are shown in the following Tables 2 and 7B.

     The unit weight at an energy density per unit weight is the total weight of an anode, a carbon-based material (coated with a polymer electrolyte layer), and an anode (air electrode) including a discharge product. Energy is a discharge amount divided by an average discharge voltage.

Carbon weight Electrolyte weight Discharge amount Energy density (mg) (mg)    (mAh) (Wh / kg) Example 3 0.40645 0.33255 0.43 190.18 Comparative Example 1 0.406 1.218 0.43 145.81

Carbon weight Electrolyte weight Discharge amount Energy density (mg) (mg)    (mAh) (Wh / kg) Example 4 1.03 0.499 0.54 237.12 Comparative Example 1 1.03 3.10 0.54 164.97

Referring to Table 1 and FIG. 6A, the energy density of the lithium air battery fabricated in Example 3 was improved by about 44 Wh / kg as compared with Comparative Example 1. FIG. Referring to Table 2 and FIG. 6B, the energy density of the lithium air cell fabricated by Example 4 was improved by about 72 Wh / kg as compared with Comparative Example 1. This is due to the decrease in the electrolyte weight at the anode (air electrode) of the lithium air battery.

1: Carbon-based material 2: Polymer electrolyte coating layer
3: void 10: lithium air battery
11: Insulation case 12: Second collector 13: Negative electrode 14: First collector
15: anode (air electrode) 16: separator
17a: air inlet port 17b: air outlet port
19: pressing member

Claims (31)

Lithium salts; And
And a polymer electrolyte layer composed of a polymer electrolyte comprising at least one hydrophilic substance coated on the surface and a hydrophobic substance,
And a part of the polymer electrolyte is anchored to the surface of the carbon-based material by non-covalent bonding or covalent bonding. The method according to claim 1,
Wherein the polymer electrolyte comprises a hydrophilic material and a hydrophobic material with a difference in contact angle with water of at least 5 degrees. 3. The method of claim 2,
Wherein the hydrophilic material has a water contact angle of less than 0 DEG to 70 DEG. 3. The method of claim 2,
Wherein the water contact angle of the hydrophobic substance is 70 DEG or more. The method according to claim 1,
Wherein a part or all of the hydrophobic substance of the polymer electrolyte is fixed on the surface of the carbon-based material by non-covalent bonding. The method according to claim 1,
Wherein a part or all of the hydrophobic substance of the polymer electrolyte is adsorbed on the surface of the carbon-based material by van der Waals bonding. The method according to claim 1,
Wherein the polymer electrolyte comprises a crosslinked polymer electrolyte. The method according to claim 1,
Wherein the polymer electrolyte comprises a block copolymer composed of a hydrophobic block and a hydrophilic block. 9. The method of claim 8,
Based material, wherein the hydrophobic block of the block copolymer is fixed to the surface of the carbon-based material and the hydrophilic block is disposed toward the surface of the carbon-based material. 9. The method of claim 8,
Wherein the block copolymer has at least two polymerized monomer blocks different from each other. 9. The method of claim 8,
Wherein the hydrophilic block of the block copolymer has a number average molecular weight (Mn) of from 500 daltons to 20,000 daltons. 9. The method of claim 8,
Wherein the hydrophilic block is a polymer block having a lithium ion conductive group in its side chain. 13. The method of claim 12,
Block polymers having a lithium ion conductivity in the side chains is TFSI ^- anion or FSI ^- anion functionalized polyacrylate block, or TFSI ^- anion or FSI ^- functionalized poly anionically methacrylate block of metal air battery anode. 9. The method of claim 8,
Wherein the block copolymer is selected from the group consisting of polyethylene glycol- b -polypropylene glycol diblock copolymer, polyethylene oxide- b -polypropylene oxide diblock copolymer, polystyrene- b -polyethylene glycol diblock copolymer, polystyrene- b- copolymer, a polystyrene - b - poly (4-vinylpyridine) diblock copolymer, a polystyrene - b - poly (meth) acrylate diblock copolymer, a polystyrene ^- b -TFSI - functionalized with anionic poly (meth) acrylate diblock copolymer, a polystyrene ^- b -FSI - an anionically functionalized poly (meth) acrylate diblock copolymer, a polyethylene glycol - b - polypropylene glycol - b - polyethylene glycol triblock copolymer, polyethylene oxide - b - poly propylene oxide - b - polyethylene oxide triblock copolymer, a polyethylene glycol - b - Lee styrene - b - polyethylene glycol triblock copolymer, and polyethylene oxide - b - polystyrene - b - polyethylene oxide triblock, metal air battery anode comprising at least one member selected from the copolymer. 9. The method of claim 8,
Wherein the block copolymer is selected from the group consisting of crosslinked polyethylene glycol- b -polypropylene glycol diblock copolymer, crosslinked polyethylene oxide- b -polypropylene oxide diblock copolymer, crosslinked polystyrene- b -polyethylene glycol diblock copolymer, polystyrene - b - polyethylene oxide diblock copolymer, cross-linked polystyrene ^- b -TFSI - functionalized with anionic poly (meth) acrylate diblock copolymer, cross-linked polystyrene ^- b -FSI - functionalized poly anionic (meth) Acrylate diblock copolymer, crosslinked polyethylene glycol- b -polypropylene glycol- b -polyethylene glycol triblock copolymer, crosslinked polyethylene oxide- b -polypropylene oxide- b -polyethylene oxide triblock copolymer, crosslinked polyethylene Glycol- b -polystyrene- b -polyethylene glycol triblock copolymer And a cross-linked polyethylene oxide- b -polystyrene- b -polyethylene oxide triblock copolymer. 9. The method of claim 8,
Wherein the block copolymer has a number average molecular weight (Mn) of from 3,000 daltons to 60,000 daltons. The method according to claim 1,
Wherein the amount of the polymer electrolyte is 10 parts by weight to 300 parts by weight based on 100 parts by weight of the carbon-based material. The method according to claim 1,
Wherein the polymer electrolyte layer has a thickness of 1 nanometer (nm) to 30 nanometers (nm). The method according to claim 1,
Wherein the polymer electrolyte layer is electrochemically stable in a range of 1.4 to 4.5 V charge / discharge voltage with respect to lithium. The method according to claim 1,
Wherein the carbon-based material is a porous carbon structure. The method according to claim 1,
Wherein the carbon-based material is selected from the group consisting of carbon nanotubes, carbon nanoparticles, carbon nanofibers, carbon nanosheets, carbon nanorods, carbon nanotubes, graphene, graphene oxide, carbon airgel, inverse opal carbon, , And anodes for metallic air cells, selected from these composites The method according to claim 1,
Wherein the content of the carbon-based material is 50 parts by weight to 80 parts by weight based on 100 parts by weight of the positive electrode. The method according to claim 1,
The lithium salt _{LiPF 6, LiBF 4, LiSbF 6} , LiAsF 6, LiN (SO 2 C 2 F 5) 2, Li (CF 3 SO 2) 2 N, LiC 4 F 9 SO 3, LiClO 4, LiAlO 2, _{LiAlCl 4, LiN (C x F} 2x + 1 SO 2) (C y F 2y + 1 SO 2) ( where, x and y are natural numbers), LiF, LiBr, LiCl, LiOH, LiI , and LiB (C ₂ O ₄ ) ₂ (lithium bis (oxalato) borate (LiBOB)). The method according to claim 1,
Wherein the content of the lithium salt is 30 parts by weight to 60 parts by weight based on 100 parts by weight of the positive electrode. The method according to claim 1,
Wherein the anode is an air electrode. A negative electrode comprising lithium or a lithium alloy;
A cathode according to any one of claims 1 to 25; And
And a separator disposed between the cathode and the anode. A polymer electrolyte comprising a polymer electrolyte composed of a polymer electrolyte comprising at least one hydrophilic substance and at least one hydrophobic substance coated on a surface of the carbonaceous material by adding a carbonaceous material, a polymer electrolyte, and a lithium salt to a solvent, 26. A method of manufacturing a positive electrode for a metal air cell, comprising the steps of: preparing a positive electrode according to any one of claims 1 to 25. 28. The method of claim 27,
Further comprising a step of adding the carbon-based material, the polymer electrolyte, and the lithium salt to the solvent, and dispersing the same before the drying, followed by filtration. 29. The method of claim 28,
Wherein the filtration process is a filter filtration process having pores of less than 1 micrometer (占 퐉). 28. The method of claim 27,
Further comprising a step of adding the carbon-based material, the polymer electrolyte, and the lithium salt to a solvent, followed by dispersion and drying, followed by a crosslinking step. 31. The method of claim 30,
Wherein the crosslinking step is a thermal crosslinking or UV crosslinking step.

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