KR101762287B1 - Lithium air battery and method for manufacturing the same - Google Patents

Abstract

The present invention relates to an anode comprising lithium; A cathode comprising a catalyst comprising porous carbon, a binder and a gas diffusion layer; And an electrolyte for transferring lithium ions generated in the negative electrode to the positive electrode. The lithium air battery of the present invention can have low overvoltage, excellent speed characteristics, high energy efficiency, and high cycle stability by applying porous carbon having a large pore and three-dimensionally connected to the anode. Further, a method for manufacturing such a lithium air battery can be provided.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a lithium-

The present invention relates to a lithium air battery and a method of manufacturing the same, and more particularly, to a lithium air battery including a porous carbon having a large pore and three-dimensionally connected thereto, and a method of manufacturing the same.

In recent years, the development of technologies for converting automobile energy sources from gasoline and light oil to electrical energy has been attracting attention, in light of an increase in carbon dioxide emissions due to the consumption of fossil fuels and a rapid change in crude oil prices. Electric vehicles have been put into practical use. For long-distance driving, it is required to increase the capacity and energy density of lithium-ion batteries, which are storage batteries. However, current lithium ion batteries have a disadvantage in that it is difficult to travel long distances due to the limited battery capacity. Therefore, lithium air cells, which are theoretically larger in capacity and higher in energy density than lithium ion batteries, are attracting attention.

Generally, a lithium air battery is provided with a cathode capable of adsorbing and releasing lithium ions, a positive electrode containing oxygen as a positive electrode active material and containing a redox catalyst for oxygen, and a lithium ion conductive medium between the positive electrode and the negative electrode do.

Lithium air cells have a theoretical energy density of over 3,000 Wh / kg, which is about 10 times the energy density of lithium ion batteries. In addition, lithium air cells are environmentally friendly and can provide improved safety over lithium-ion batteries.

A lithium air battery is a battery having a positive electrode which uses oxygen in the air as an active material and is capable of charging and discharging the battery by performing oxidation / reduction reaction of oxygen in the positive electrode.

Conventional lithium-ion batteries exhibit non-conductive, non-conductive, high overvoltage, poor speed characteristics, low energy efficiency and low cycle stability due to solid Li ₂ O ₂ during the discharge process. As a result, the energy efficiency at the time of charging and discharging was significantly lower than that of the lithium ion battery. Therefore, there is a need for a lithium ion battery having improved energy efficiency during charging and discharging.

In order to solve the above-described problems, US-A-2008-0028164 discloses a lithium air battery in which the chemical properties of the electrolyte are improved. However, there is a limitation in improving the charging / discharging performance of the lithium air battery, and there is a disadvantage in that durability is deteriorated due to insufficient bonding.

In addition, studies have been made to improve the energy efficiency of lithium air cells by applying a positive electrode catalyst using conductive carbon such as Super P. However, the Super P carbon catalyst exhibits excellent activity in the oxygen reduction reaction, but the catalyst activity is not remarkably exhibited at the time of charging. Therefore, the lithium ion battery has high overvoltage due to Li ₂ O ₂ , inferior speed characteristics, low energy efficiency and low cycle stability It is not possible to sufficiently improve the performance.

An object of the present invention is to provide a lithium air battery having a low overvoltage, an excellent speed characteristic, a high energy efficiency and a high cycle stability by applying porous carbon having a large pore and three dimensionally connected to the anode to solve the above problems There is.

Another object of the present invention is to provide a method of manufacturing such a lithium air battery.

According to an aspect of the present invention,

A negative electrode comprising lithium; A cathode comprising a catalyst comprising porous carbon, a binder and a gas diffusion layer; And an electrolyte for transferring the lithium ions generated in the negative electrode to the positive electrode.

The porous carbon may include mesopores having a diameter of 10 to 50 nm formed by linking the carbon skeleton and the carbon skeleton.

The mesopore can have a diameter of 20 to 30 nm.

The mesopores may be three-dimensionally connected to the porous carbon.

The porous carbon is located in the carbon skeleton and may have a diameter of 1 to 10 nm.

The BET surface area of the porous carbon may be 500 to 1,200 m < ² > / g.

The porous carbon may comprise MSU-F-C (Michigan State University-F-C).

The porous carbon-containing catalyst may be at least one selected from the group consisting of carbon black, denka black, DLC (diamond like carbon), activated carbon, graphite, hard carbon, soft carbon, super P, black) and Vulcan XC-72 (Vulcan XC-72).

The anode catalyst may be carbon black.

In the catalyst containing the porous carbon, the anode catalyst may be 30 to 100 parts by weight based on 100 parts by weight of the porous carbon.

The gas diffusion layer may be any one selected from carbon paper, stainless steel mesh, and nanoporous gold.

The binder may include at least one selected from polyvinylidene fluoride (PVDF), polytetrafluoroethylene, polytrifluorostyrene sulfonic acid, and Nafion 117 .

The electrolyte may include a lithium salt and an organic solvent.

The lithium salt is selected from the group consisting of lithium trifluoromethanesulfonate, lithium bis (trifluoromethane) sulfonimide, lithium perchlorate, lithium hexafluoroethane (LiAsF ₆ ), LiPF ₆ , LiBF ₄ , tetraalkylammonium, lithium nitrate (LiNO ₃ ), lithium sulfate (Li ₂ SO ₄ ) and lithium iodide (LiI) . ≪ / RTI >

The organic solvent is selected from the group consisting of tetraethylene glycol dimethyl ether (TEGDME, G4), ethylene carbonate (EC), propylene carbonate (PC), dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (DME),? -Butyrolactone (GBL), tetrahydrofuran (THF), 1,3-dioxolane (DOXL), dimethyl ether (DEE), methyl propionate (DMSO), acetonitrile (AN), triethylene glycol dimethyl ether (G3), and diethylene glycol dimethyl ether (DEGDME) in the presence of at least one selected from the group consisting of sulfolane (S), dimethylsulfoxide .

According to another aspect of the present invention,

(a) reacting a mixed solution comprising a multiblock copolymer comprising a hydrophobic polymer block and a hydrophilic polymer block, a silica precursor, and an organic solvent; (b) heat treating the resultant product of step (a) in an air atmosphere to produce silica; (c) preparing a mixture comprising the silica, the aluminum precursor and the organic solvent, and evaporating the organic solvent; (d) subjecting the resultant of step (c) to heat treatment in an air atmosphere to produce an aluminum-silica composite; (e) mixing the aluminum-silica complex and the carbon precursor and reacting them; (f) heat treating the result of step (e) in an inert gas atmosphere; And (g) contacting the resultant of step (f) with hydrofluoric acid.

Wherein the multiblock copolymer is selected from the group consisting of polyethylene oxide-polypropylene oxide-polyethylene oxide block copolymer, polyethylene oxide-polystyrene-polyethylene oxide block copolymer, polyethylene oxide-polyisoprene-polyethylene oxide block copolymer, polyimide- A poly (ethylene oxide) -polystyrene block copolymer, a polyethylene oxide-poly (styrene) block copolymer, a polyethylene oxide-polyimide block copolymer and a poly (4-vinylpyridine) -polystyrene block copolymer.

Wherein the silica precursor is selected from the group consisting of sodium silicate, tetraethylorthosilicate, n-octadecyltrimethoxysilane, diglycerylsilane, tetramethylorthosilicate, methyl triethoxysilane, methyltriethoxysilane, It may be at least one selected from the group consisting of methyl trimethoxysilane, vinyl trimethoxysilane and 3-aminopropyl trimethoxysilane.

The aluminum precursor may be at least one selected from aluminum chloride hexahydrate (AlCl ₃ .6H ₂ O), aluminum acetylacetonate and aluminum tri-sec-butoxide.

Wherein the carbon precursor is selected from the group consisting of furfuryl alcohol, resol, furfuryl amine, sucrose, glucose, dopamine, phenol, phenanthrene ), Polyacronitrile, and polyvinyl alcohol. [0031] The term " polyvinyl alcohol "

The lithium air battery of the present invention can have low overvoltage, excellent speed characteristics, high energy efficiency, and high cycle stability by applying porous carbon having a large pore and three-dimensionally connected to the anode.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view schematically showing the state after charging and discharging the porous carbon of the present invention and the conventional porous carbon; FIG.
FIG. 2 shows experimental results of surface area, pore size and volume of MSU-FC prepared according to Preparation Example 1 and CMK-3 prepared according to Preparation Example 2.
3 is a TEM photograph of MSU-FC prepared according to Preparation Example 1 and CMK-3 prepared according to Preparation Example 2. FIG.
4 shows the results of measurement of the discharge capacity according to the current density of the lithium air battery manufactured according to the device example 2, the device comparison example 1, and the device comparison example 3. As shown in Fig.
FIG. 5 is a graph showing the results of measurement of charging / discharging overvoltage according to the current density of the anode manufactured according to Example 2, Comparative Example 1, and Comparative Example 3. FIG.
6 shows the results of measurement of EIS before and after the discharge of the lithium air cell produced according to the element embodiment 1 and the element comparison example 2. Fig.
7 shows the results of measurement of the cycle characteristics of the lithium air battery produced according to the device example 2, the device comparative example 1, and the device comparative example 3. Fig.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention.

However, the following description does not limit the present invention to specific embodiments. In the following description of the present invention, detailed description of related arts will be omitted if it is determined that the gist of the present invention may be blurred .

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms "comprises ", or" having ", and the like, specify that the presence of stated features, integers, steps, operations, elements, or combinations thereof, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, or combinations thereof.

Hereinafter, the lithium air battery of the present invention will be described in detail.

The lithium air battery of the present invention may include a cathode including lithium, a catalyst containing porous carbon, a cathode including a binder and a gas diffusion layer, and an electrolyte for transferring lithium ions generated in the cathode to the anode.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view schematically showing the state after filling and discharging the porous carbon (MSU-F-C) and the conventional porous carbon (CMK-3) of the present invention at a high current density and a low current density, respectively. Here, the porous carbon of the present invention is MSU-F-C and the conventional porous carbon is CMK-3. However, the scope of the present invention is not limited thereto.

Referring to FIG. 1, at low current density, the non-conductive, solid Li ₂ O ₂ produced in the anode during the discharge process is deposited on the surface of the porous carbon thinly to prevent pores, Of the porous carbon (CMK-3) can react to the inside of the porous carbon.

On the other hand, in the high current density of Li ₂ O ₂ stacked thickly on the surface of the porous carbon for the size of the pore small conventional porous carbon, Li ₂ O ₂ can take place this reaction prevents the pores to the inside of the porous carbon no catalyst Can be reduced.

Accordingly, the porous carbon to be applied to the lithium air battery may have a relatively large pore size and preferably have a three-dimensionally connected structure.

The porous carbon of the present invention may include mesopores having a diameter of 10 to 50 nm formed by linking the carbon skeleton and the carbon skeleton.

The mesopores may have a diameter of preferably 15 nm to 40 nm, more preferably 20 nm to 30 nm.

The porous carbon may be located in the carbon skeleton and may include micropores having a diameter of 1 to 10 nm. The micropores preferably have a diameter of 3 nm to 7 nm, more preferably 4 nm to 5 nm Lt; / RTI >

The porous carbon may have a BET surface area of 500 to 1,200 m ² / g, preferably 600 to 1,100 m ² / g, more preferably 700 to 1,000 m ² / g.

The mesopore volume may be in the range of 1.5 to 3 cm ³ / g, preferably 1.6 to 2.6 cm ³ / g, more preferably 1.7 to 2.2 cm ³ / g.

The porous carbon preferably comprises MSU-F-C (Michigan State University-F-C).

In some cases, the porous carbon-containing catalyst may contain at least one of carbon black, denka black, DLC (diamond like carbon), activated carbon, graphite, hard carbon, soft carbon, (P), ketjen black, Vulcan XC-72 (Vulcan XC-72), and the like, preferably carbon black.

The catalyst containing the porous carbon may be 30 to 100 parts by weight, preferably 40 to 95 parts by weight, more preferably 50 to 90 parts by weight, based on 100 parts by weight of the porous carbon.

The gas diffusion layer may be carbon paper, stainless steel mesh, nanoporous gold, or the like, preferably carbon paper.

The binder may be polyvinylidene fluoride (PVDF), polytetrafluoroethylene, polytrifluorostyrene sulfonic acid, Nafion 117, etc. Preferably, the binder is polyvinyl Lt; / RTI > fluoride.

The electrolyte may include a lithium salt and an organic solvent.

The lithium salt is selected from the group consisting of lithium trifluoromethanesulfonate, lithium bis (trifluoromethane) sulfonimide, lithium perchlorate, lithium hexafluoroethane (LiAsF ₆ ), LiPF ₆ , LiBF ₄ , tetraalkylammonium, lithium nitrate (LiNO ₃ ), lithium sulfate (Li ₂ SO ₄ ), lithium iodide (LiI) And preferably lithium trifluoromethane sulfonate.

The organic solvent is selected from the group consisting of tetraethylene glycol dimethyl ether (TEGDME, G4), ethylene carbonate (EC), propylene carbonate (PC), dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate Dimethoxyethane (DME),? -Butyrolactone (GBL), tetrahydrofuran (THF), 1,3-dioxolane (DOXL), dimethyl ether (DEE), methyl propionate May include sulfolane (S), dimethylsulfoxide (DMSO), acetonitrile (AN), triethylene glycol dimethyl ether (G3), diethylene glycol dimethyl ether (DEGDME) Lt; RTI ID = 0.0 > tetraethylene < / RTI > glycol dimethyl ether.

The present invention also provides a method for manufacturing the above-described lithium air battery.

The method of manufacturing the lithium air battery of the present invention may include a method of manufacturing the positive electrode to be described in detail below.

In the method of preparing the anode, a mixed solution containing a multiblock copolymer including a hydrophobic polymer block and a hydrophilic polymer block, a silica precursor, and an organic solvent is reacted (step a).

The multiblock copolymer comprising the hydrophobic polymer block and the hydrophilic polymer block may be a double block copolymer or a triblock copolymer.

The multiblock copolymer may be selected from the group consisting of polyethylene oxide-polypropylene oxide-polyethylene oxide block copolymer, polyethylene oxide-polystyrene-polyethylene oxide block copolymer, polyethylene oxide-polyisoprene-polyethylene oxide block copolymer, polyimide-polystyrene- (4-vinylpyridine) -polystyrene block copolymer and the like can be used, but it is preferable to use a poly (ethylene oxide) -polystyrene block copolymer such as polyethylene oxide-polystyrene block copolymer, polyethylene oxide-polystyrene block copolymer, polyethylene oxide- Polyethylene oxide-polypropylene oxide-polyethylene oxide block copolymer.

The silica precursor may be selected from the group consisting of sodium silicate, tetraethylorthosilicate, n-octadecyltrimethoxysilane, diglycerylsilane, tetramethylorthosilicate, methyl triethoxysilane, methyltriethoxysilane, Methyl trimethoxysilane, vinyl trimethoxysilane, 3-aminopropyl trimethoxysilane and the like can be used, but sodium silicate can be preferably used.

The organic solvent may be trimethylbenzene, 1-butanol, n-hexane, n-heptane, cumene or the like, preferably trimethylbenzene.

Next, the resultant product of step (a) is heat-treated in an air atmosphere to produce silica (step b).

The heat treatment may be performed at 400 to 800 ° C, preferably at 450 to 700 ° C, more preferably at 500 to 600 ° C.

When performed at the heat treatment temperature, the heat treatment may be performed for 3 to 5 hours, but is not limited thereto. The heat treatment time may vary depending on the heat treatment temperature.

Next, a mixture comprising the silica, the aluminum precursor and the organic solvent is prepared and the organic solvent is evaporated (step c).

The aluminum precursor may be aluminum chloride hexahydrate (AlCl ₃ .6H ₂ O), aluminum acetylacetonate, aluminum tri-sec-butoxide and the like, Aluminum hexahydrate.

The organic solvent may be ethanol, methanol, water, acetone, acetonitrile, tetrahydrofuran, dimethoxyfuran and the like, preferably ethanol.

Next, the resultant product of step (c) is heat-treated in an air atmosphere to prepare an aluminum-silica composite (step d).

The heat treatment may be performed at 400 to 800 ° C, preferably at 450 to 700 ° C, more preferably at 500 to 600 ° C.

When performed at the heat treatment temperature, the heat treatment may be performed for 3 to 5 hours, but is not limited thereto. The heat treatment time may vary depending on the heat treatment temperature.

Next, the aluminum-silica composite and the carbon precursor are mixed and reacted (step e).

The carbon precursor may be selected from the group consisting of furfuryl alcohol, resol, furfuryl amine, sucrose, glucose, dopamine, phenol, phenanthrene ), Polyacronitrile, polyvinyl alcohol, and the like, but may preferably be furfuryl alcohol.

The amount of the carbon precursor is preferably equal to the volume of the pores of the aluminum-silica composite. At this time, an acid catalyst may be further added.

The acid catalyst may be a dicarboxylic acid. Specific examples thereof include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid and sebacic acid. .

Next, the result of step (e) is heat treated in an inert gas atmosphere (step f).

The inert gas may include nitrogen, argon, helium, krypton or neon gas.

The heat treatment may be performed at 400 to 1,000 ° C, preferably 500 to 950 ° C, more preferably 600 to 900 ° C.

When performed at the heat treatment temperature, the heat treatment may be performed for 1 to 3 hours, but is not limited thereto. The heat treatment time may vary depending on the heat treatment temperature.

Finally, the result of step (f) is contacted with hydrofluoric acid (step c).

Aluminum and silica are etched by the contact to produce porous carbon, and the porous carbon-coated anode can be produced.

In addition, a lithium air battery can be manufactured by applying the positive electrode.

[Example]

Hereinafter, preferred embodiments of the present invention will be described. However, this is for illustrative purposes only, and thus the scope of the present invention is not limited thereto.

Manufacturing example  One: MSU Preparation of -F-C

First, 9.7 g of Pluronic P-123 was dissolved in 200 mL of distilled water, 4.43 mL of acetic acid was added, and then the temperature was maintained at 60 占 폚. Pluronic P-123 is a PEO-PPO-PEO block copolymer (polyethylene oxide-polypropylene oxide-polyethylene oxide block copolymer) in which 20 ethylene oxide units and 70 propylene oxide units are connected on both sides to be. Then, 5.67 mL of 1,3,5-trimethylbenzene (TMB, 1,3,5-trimethylbenzene) was added and stirred for 1 hour to prepare a P-123 solution. 16 mL of sodium silicate and 200 mL of distilled water were mixed, and then the above P-123 solution was added and stirred at 60 ° C for 20 hours to prepare a mixed solution. The mixed solution was maintained at 100 DEG C for 24 hours, filtered to filter out the precipitate, and the precipitate was added to a solution containing 200 mL of ethanol and 5 mL of hydrochloric acid. The solution was filtered again, the precipitate was filtered, and the precipitate was heat-treated for 4 hours in an air atmosphere at 550 ° C to prepare MSU-F-Si.

The mixture was mixed with 1.25 g of AlCl ₃ .6H ₂ O per 6 g of the MSU-F-Si, dissolved in 100 mL of ethanol, and the ethanol was slowly evaporated to obtain a precipitate. The precipitate was heat-treated for 4 hours in an air atmosphere at 550 ° C to produce Al-MSU-F-Si.

The pore volume of Al-MSU-F-Si was measured, and the mixture was evenly mixed with furfuryl alcohol so as to match the volume. The mixture was left under vacuum for 30 minutes and then held at 85 [deg.] C for 8 hours under vacuum. Next, the heat-treated mixture was heat-treated at 850 ° C for 2 hours in a nitrogen atmosphere. The heat-treated mixture was put in a solution of 200 mL of distilled water, 200 mL of ethanol and 20 mL of hydrofluoric acid, and the mixture was etched for 3 hours. Next, the solution was filtered and filtered, and then dried to prepare MSU-F-C.

Manufacturing example  2: CMK -3 production

8 g of Pluronic P-123 was dissolved in a solution of 210 ml of distilled water and 40 ml of hydrochloric acid, and the mixture was stirred evenly at 40 ° C. Next, 18.2 mL of TEOS (tetraethoxyorthosilicate) was added and the mixture was allowed to stand for 24 hours. The mixed solution was maintained at 100 캜 for 24 hours, and then filtered to obtain a precipitate. The precipitate was subjected to heat treatment in an air atmosphere at 550 캜 for 4 hours to prepare SBA-15.

The pore volume of SBA-15 was measured, and a mixed solution of furfuryl alcohol and oxalic acid was prepared so that the total pore volume was the same (molar ratio of furfuryl alcohol to oxalic acid was 200: 1). The mixed solution and SBA-15 were evenly mixed and kept in a vacuum for 30 minutes to prepare a mixture. Next, the mixture was held in a vacuum state at 85 캜 for 24 hours, and then heat-treated at 850 캜 in a nitrogen atmosphere for 2 hours to prepare a heat-treated mixture. The heat-treated mixture was put in a solution of 200 mL of distilled water, 200 mL of ethanol and 20 mL of hydrofluoric acid, and the mixture was etched for 3 hours. Next, the solution was filtered and sieved, followed by drying to produce CMK-3.

Example  1: Preparation of positive electrode ( MSU -F-C)

Carbon paper was cut and prepared to have a diameter of 15 mm. MSU-F-C prepared according to Preparation Example 1 was prepared as a carbon catalyst. The carbon catalyst and the binder polyvinylidene fluoride (PVDF) were mixed in a ratio of 9: 1 and dissolved in NMP (N-methyl-2-pyrrolidone) to prepare a carbon catalyst solution. 0.7 mg of the carbon catalyst solution was placed on the carbon paper, and dried at 110 캜 to remove NMP, thereby preparing a positive electrode.

Example  2: Preparation of positive electrode ( MSU -F-C + SP )

A positive electrode was prepared in the same manner as in Example 1 except that MSU-F-C prepared in Preparation Example 1 and Super P (SP) were mixed in a ratio of 2: 1.

Device Example  1: Manufacture of lithium air cell MSU -F-C)

Tetraethylene glycol dimethyl ether (TEGDME) and lithium trifluoromethanesulfonate were mixed at a molar ratio of 1: 4 to prepare an electrolyte.

Three layers of lithium foil were stacked and cut to a diameter of 16 mm to prepare a negative electrode.

A 2032 coin cell was prepared using the positive electrode prepared in Example 1, the negative electrode and a GFC separator (glass microfiber filter, Whatman Co.), and the electrolyte was injected.

Device Example  2: Preparation of Lithium Air Cell MSU -F-C + SP )

A lithium air cell was manufactured in the same manner as in Example 1 except that the anode prepared in Example 2 was used instead of the anode prepared in Example 1.

Comparative Example  1: Preparation of positive electrode ( SP )

A positive electrode was prepared in the same manner as in Example 1, except that Super P (SP) was used instead of MSU-F-C prepared according to Preparation Example 1.

Comparative Example  2: Preparation of positive electrode ( CMK -3)

A positive electrode was prepared in the same manner as in Example 1, except that CMK-3 prepared in Preparation Example 2 was used instead of MSU-F-C prepared in Preparation Example 1.

Comparative Example  3: Preparation of positive electrode ( CMK -3+ SP )

A positive electrode was prepared in the same manner as in Example 1, except that CMK-3 prepared in Preparation Example 2 and Super P (SP) were mixed in a ratio of 2: 1.

Device comparison example  1: Manufacture of lithium air cell SP )

A lithium air cell was produced in the same manner as in Example 1 except that the positive electrode prepared in Comparative Example 1 was used instead of the positive electrode prepared in Example 1.

Device comparison example  2: Preparation of Lithium Air Cell CMK -3)

A lithium air cell was produced in the same manner as in Example 1 except that the positive electrode prepared in Comparative Example 2 was used instead of the positive electrode prepared in Example 1.

Device comparison example  3: Manufacture of Lithium Air Battery CMK -3+ SP )

A lithium air cell was produced in the same manner as in Example 1 except that the positive electrode prepared in Comparative Example 3 was used instead of the positive electrode prepared in Example 1.

[Test Example]

Test Example  1: Carbon catalyst identification

2 (a) shows the results of nitrogen adsorption / desorption experiments of MSU-FC prepared according to Preparation Example 1 and CMK-3 prepared according to Preparation Example 2, and FIG. 2 (b) And Fig. 3 is a TEM photograph.

2 (a) and 2 (b), MSU-FC prepared according to Preparation Example 1 had a pore size of 30 nm, a pore volume of 1.86 cm ³ / g, and a surface area of 863 m ² / g appear. Small pores of about 5 nm were also generated. CMK-3 prepared according to Production Example 2 had a pore size of 3.3 nm, a pore volume of 1.25 cm ³ / g, and a surface area of 1,180 m ² / g.

Referring to FIG. 3, MSU-F-C prepared in Preparation Example 1 is a catalyst in which pores are three-dimensionally connected, and CMK-3 prepared in Preparation Example 2 has a pore structure in a two-dimensional channel form.

Thus, it can be seen that the surface area of MSU-F-C prepared according to Preparation Example 1 is smaller than that of CMK-3 prepared according to Preparation Example 2, but the pore size is about 10 times larger.

Test Example  2: Measurement of discharge capacity according to current density

4 shows the results of measurement of the discharge capacity according to the current density of the lithium air battery manufactured according to the device example 2, the device comparison example 1, and the device comparison example 3. As shown in Fig.

Referring to FIG. 4, a lithium air battery manufactured according to Comparative Example 3, which includes the CMK-3 carbon catalyst having the largest surface area at a low current density of about 500 mA / g or less, exhibited the highest discharge capacity. However, as the current density gradually increases, the lithium-air battery (CMK-3 + SP) manufactured according to Comparative Example 3 has a large decrease in discharge capacity. As a result, according to Example 2 of the current density higher than 1000 mA / The produced lithium air battery (MSU-F-C + SP) showed the highest discharge capacity.

Therefore, it was confirmed that the lithium air battery (MSU-F-C + SP) manufactured according to the second embodiment had the highest discharge capacity at a high current density. This is presumably because the MSU-F-C carbon catalyst of the lithium air cell has relatively large pores connected three-dimensionally.

Test Example 3: Charge / discharge overvoltage measurement according to current density

FIG. 5 (a) shows the result of measuring the discharge overvoltage according to the current density of the anode manufactured according to Example 2, Comparative Example 1, and Comparative Example 3, and (b) is a result of measuring the charging overvoltage.

The discharging capacity was discharged to a limited capacity of 1,000 mAh / g, and the same capacity was again charged to measure the over-voltage. The overvoltage indicates the difference between the theoretical potential difference between the reaction occurring in the charging and discharging process and the redox reaction of lithium and the actual charging and discharging potential. The lower the overvoltage, the better the efficiency.

5 (a) and 5 (b), the charge overpotential and discharge overpotential of the anode (CMK-3 + SP) prepared according to Comparative Example 3 at the low current density of about 500 mA / Respectively. However, as the current density gradually increased, the positive electrode (CMK-3 + SP) prepared in accordance with Comparative Example 3 increased in both the charging overpotential and the discharge overpotential, resulting in a high current density of 1,000 mA / The anode (MSU-F-C + SP) has the lowest charge overvoltage and discharge overvoltage.

Therefore, it is expected that the anode (MSU-F-C + SP) produced according to Example 2 has the best efficiency by having low charge over-discharge and discharge over-voltage at high current density.

Test Example 4: Electrochemical Impedence Spectroscopy (EIS) Measurement

6 shows the results of measurement of EIS before and after the discharge of the lithium air battery produced according to the element embodiment 1 and the element comparison example 2. Fig. Each lithium air cell was discharged at 1,000 mAh / g.

6, a lithium ion battery (MSU-FC before discharge) manufactured according to Example 1 of the pre-discharge device is higher than a lithium air battery (CMK-3 before discharge) manufactured according to Comparative Example 2 , Which indicates that the mass transfer in the lithium air cell produced according to the Device Example 1 is faster than the lithium air cell made according to the Device Comparative Example 2. [ As a result of the EIS measurement of the lithium air battery after discharging, the lithium air battery (CMK-3 after discharge) manufactured according to the comparative example 2 was higher than the lithium air battery (MSU-FC after discharge) The peak frequency is greatly reduced and this also indicates that the mass transfer in the lithium air cell produced according to the Device Example 1 is faster than the lithium air cell made according to the Device Comparative Example 2. [

Therefore, it was found that the lithium air cell manufactured according to the Embodiment Example 1 is superior in the mass transfer ability in the lithium air cell. This is because the CMU-3 prepared according to Preparation Example 2 has a narrow pore and a two-dimensional channel shape, whereas the MSU-FC prepared according to Preparation Example 1 has a relatively large pore and is a three- However, the ability of the material to transfer into the catalyst is considered to be better.

Test Example  5: Cycle  Identify characteristics

The cyclic characteristics of the lithium air cells manufactured according to the device example 2, the device comparison example 1 and the device comparative example 3 were measured and shown in Fig. 7 (a), and the cycle was turned to turn the lithium air battery 7 (b) and 7 (c) show the results of measuring the cycle characteristics by forming a new anode by attaching a new anode and a new cathode by attaching a new cathode to a new anode. The current density was 500 mA / g, and it was tested by discharging to 1,000 mAh / g.

Referring to FIG. 7 (a), the cycle characteristics of the lithium air battery (MSU-F-C + SP) manufactured according to the second embodiment were the most excellent. On the contrary, the lithium air battery (Super P, CMK-3 + SP) manufactured according to the device comparison example 1 and the device comparison example 3 showed relatively low cycle characteristics.

Referring to FIGS. 7 (b) and 7 (c), a lithium air battery (used MSU-F-C + SP cathode) manufactured according to the Embodiment 2 of the present invention, , But it was found that the cycle did not return to the lithium air battery (Super P, CMK-3 + SP) manufactured according to the device comparison example 1 and the device comparison example 3.

Therefore, it was judged that the lithium air cell produced according to the second embodiment of the present invention exhibited better cycle characteristics by including MSU-F-C, which is a relatively large pore and a three-dimensionally connected catalyst.

The scope of the present invention is defined by the appended claims rather than the detailed description and all changes or modifications derived from the meaning and scope of the claims and their equivalents are to be construed as being included within the scope of the present invention do.

Claims (20)

A negative electrode comprising lithium;
A cathode comprising a catalyst comprising porous carbon, a binder and a gas diffusion layer; And
And an electrolyte for transferring lithium ions generated in the negative electrode to the positive electrode,
Wherein the porous carbon comprises mesopores having a diameter of 10 to 50 nm formed by the connection of the three-dimensional carbon skeleton and the carbon skeleton,
The mesopores are three-dimensionally connected to the porous carbon,
Wherein the porous carbon comprises micropores having a diameter of 1 to 10 nm, the micropores are located in the carbon framework,
Wherein the porous carbon has a BET surface area of 700 to 1,200 m < ² > / g.
Lithium air battery. delete The method according to claim 1,
Wherein the mesopores have a diameter of 20 to 30 nm. delete delete delete The method according to claim 1,
Wherein the porous carbon comprises MSU-FC (Michigan state University-FC). The method according to claim 1,
The porous carbon-containing catalyst may be at least one selected from the group consisting of carbon black, denka black, DLC (diamond like carbon), activated carbon, graphite, hard carbon, soft carbon, super P, black) and Vulcan XC-72 (Vulcan XC-72). < IMAGE > 9. The method of claim 8,
Wherein the positive electrode catalyst is carbon black. 9. The method of claim 8,
Wherein the catalyst comprising the porous carbon is such that the amount of the positive electrode catalyst is 30 to 100 parts by weight based on 100 parts by weight of the porous carbon. The method according to claim 1,
Wherein the gas diffusion layer is any one selected from the group consisting of carbon paper, stainless steel mesh, and nanoporous gold. The method according to claim 1,
Characterized in that the binder comprises at least one selected from the group consisting of polyvinylidene fluoride (PVDF), polytetrafluoroethylene, polytrifluorostyrene sulfonic acid and Nafion 117 . The method according to claim 1,
Wherein the electrolyte comprises a lithium salt and an organic solvent. 14. The method of claim 13,
The lithium salt is selected from the group consisting of lithium trifluoromethanesulfonate, lithium bis (trifluoromethane) sulfonimide, lithium perchlorate, lithium hexafluoroethane (LiAsF ₆ ), LiPF ₆ , LiBF ₄ , tetraalkylammonium, lithium nitrate (LiNO ₃ ), lithium sulfate (Li ₂ SO ₄ ) and lithium iodide (LiI) And a lithium ion battery. 14. The method of claim 13,
The organic solvent is selected from the group consisting of tetraethylene glycol dimethyl ether (TEGDME, G4), ethylene carbonate (EC), propylene carbonate (PC), dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate Dimethoxyethane (DME),? -Butyrolactone (GBL), tetrahydrofuran (THF), 1,3-dioxolane (DOXL), dimethyl ether (DEE), methyl propionate And at least one member selected from the group consisting of sulfolane (S), dimethylsulfoxide (DMSO), acetonitrile (AN), triethylene glycol dimethyl ether (G3) and diethylene glycol dimethyl ether Lt; / RTI > air cell. (a) reacting a mixed solution comprising a multiblock copolymer comprising a hydrophobic polymer block and a hydrophilic polymer block, a silica precursor, and an organic solvent;
(b) heat treating the resultant product of step (a) in an air atmosphere to produce silica;
(c) preparing a mixture comprising the silica, the aluminum precursor and the organic solvent, and evaporating the organic solvent;
(d) subjecting the resultant of step (c) to heat treatment in an air atmosphere to produce an aluminum-silica composite;
(e) mixing the aluminum-silica complex and the carbon precursor and reacting them;
(f) heat treating the result of step (e) in an inert gas atmosphere; And
(g) contacting the resultant of step (f) with hydrofluoric acid to produce porous carbon; Including the
Wherein the porous carbon comprises mesopores having a diameter of 10 to 50 nm formed by the connection of the three-dimensional carbon skeleton and the carbon skeleton,
The mesopores are three-dimensionally connected to the porous carbon,
Wherein the porous carbon comprises micropores having a diameter of 1 to 10 nm, the micropores are located in the carbon framework,
Wherein the porous carbon has a BET surface area of 700 to 1,200 m < ² > / g.
A method for manufacturing a lithium air battery, comprising the steps of: 17. The method of claim 16,
Wherein the multiblock copolymer is selected from the group consisting of polyethylene oxide-polypropylene oxide-polyethylene oxide block copolymer, polyethylene oxide-polystyrene-polyethylene oxide block copolymer, polyethylene oxide-polyisoprene-polyethylene oxide block copolymer, polyimide- (4-vinylpyridine) -polystyrene block copolymer. The polyolefin resin composition according to any one of (1) to (4), wherein the polyolefin block copolymer is selected from the group consisting of a polystyrene block copolymer, a polystyrene block copolymer, a polystyrene block copolymer, a polystyrene block copolymer, Wherein the lithium ion battery is a lithium ion battery. 17. The method of claim 16,
Wherein the silica precursor is selected from the group consisting of sodium silicate, tetraethylorthosilicate, n-octadecyltrimethoxysilane, diglycerylsilane, tetramethylorthosilicate, methyl triethoxysilane, Wherein the electrolyte is at least one selected from the group consisting of methyl trimethoxysilane, vinyl trimethoxysilane and 3-aminopropyl trimethoxysilane. 17. The method of claim 16,
Wherein the aluminum precursor is at least one selected from aluminum chloride hexahydrate (AlCl ₃ .6H ₂ O), aluminum acetylacetonate and aluminum tri-sec-butoxide. A method of manufacturing a lithium air cell. 17. The method of claim 16,
Wherein the carbon precursor is selected from the group consisting of furfuryl alcohol, resol, furfuryl amine, sucrose, glucose, dopamine, phenol, phenanthrene ), Polyacronitrile, and polyvinyl alcohol. ≪ RTI ID = 0.0 > 11. < / RTI >

Images