Cathode for lithium air battery having low cell resistance and high mechanical property and preparing method thereof

Abstract

The present invention relates to a positive electrode for a lithium-air battery and a method for manufacturing the same, which is constructed using an electrically conductive fiber-type filler instead of a binder, and is characterized by low cell resistance and excellent mechanical properties.

Description

Technology Field

[0001] The present invention relates to a positive electrode for a lithium-air battery and a method for manufacturing the same, which is constructed using an electrically conductive fiber-type filler instead of a binder, and is characterized by low cell resistance and excellent mechanical properties. Background Technology

[0002] Recently, as the limitations of lithium-ion batteries in cutting-edge technologies such as EVs (electric vehicles) and HEVs (hybrid electric vehicles) have become apparent, interest in next-generation lithium batteries capable of overcoming their drawbacks, such as low energy density and limited capacity, is increasing.

[0003] Lithium-air batteries, one of the next-generation lithium batteries, are systems that utilize oxygen from the air as the cathode active material. Because these lithium-air batteries can receive an unlimited supply of oxygen from the air, they have superior capacity and energy density compared to lithium-ion batteries.

[0004] The charging and discharging of a lithium-air battery proceeds through a redox reaction between lithium at the negative electrode and oxygen at the positive electrode. During discharge, lithium ions oxidized at the negative electrode move through the electrolyte and the separator to the positive electrode, where they meet with oxygen ions reduced at the positive electrode to produce lithium peroxide (Li2O2), which is a discharge product.

[0005] Meanwhile, to increase the energy density per unit weight of lithium-air batteries, nano-sized carbon materials with a large specific surface area must be used as cathode materials. Conventionally, cathodes were manufactured by bonding the aforementioned cathode materials with a binder. However, most of these binders are polymeric materials that lack electrical conductivity and act as resistance within the cell, and oxygen radicals (O2) formed within the battery during charging and discharging - It can be decomposed by ) and degrade the anode. Prior art literature

[0006] Korean Patent Publication No. 10-2020-0051225 The problem to be solved

[0007] The present invention aims to provide a positive electrode for a lithium-air battery with low cell resistance and a method for manufacturing the same.

[0008] The present invention aims to provide a positive electrode for a lithium-air battery with excellent mechanical properties and a method for manufacturing the same.

[0009] The objectives of the present invention are not limited to those mentioned above. The objectives of the present invention will become clearer from the following description and will be realized by the means and combinations thereof described in the claims. means of solving the problem

[0010] A positive electrode for a lithium-air battery according to one embodiment of the present invention may include: a sheet layer having a mesh structure formed by bundling bundle-type carbon nanotubes; and a fibrous filler having electrical conductivity that exists intertwined with the bundle-type carbon nanotubes inside the sheet layer.

[0011] The bundled carbon nanotubes above are aggregated from a plurality of carbon nanotube units, and the carbon nanotube units may have a diameter of 10 nm to 50 nm.

[0012] The above carbon nanotube unit may have a length of 100 nm to 5 µm.

[0013] The above carbon nanotube monomer has a specific surface area of ​​150 m² 2 / g to 300m 2 It could be / g.

[0014] The bundled carbon nanotubes may have a diameter of 2 µm to 10 µm.

[0015] The bundled carbon nanotubes above may have a length of 50 µm to 100 µm.

[0016] The above fibrous filler may include at least one selected from the group consisting of carbon fiber, carbon nanofiber, vapor grown carbon fiber (VGCF), silver wire, stainless steel wire, platinum wire, and combinations thereof.

[0017] The above fibrous filler may have a length of 1 mm to 10 mm.

[0018] The anode may comprise 95% to 98% by weight of the bundled carbon nanotubes; and 2% to 5% by weight of the fibrous filler.

[0019] The above anode may have a porosity of 75% to 90%.

[0020] A positive electrode for a lithium-air battery according to one embodiment of the present invention may include the step of preparing a solution by dispersing bundle-type carbon nanotubes and a fiber-type filler in a solvent; and the step of filtering the solution.

[0021] The above manufacturing method may involve preparing a paste by mixing the bundled carbon nanotubes and the fiber-type filler, and then dispersing the paste in a solvent to prepare the solution.

[0022] The above manufacturing method may involve irradiating the above solution with ultrasound to disperse the bundled carbon nanotubes and the fibrous filler.

[0023] The above manufacturing method may further include a step of pressurizing the filtered product. Effects of the invention

[0024] According to the present invention, since the anode is implemented using an electrically conductive fiber-type filler without using a binder, a cathode for a lithium-air battery with low cell resistance can be obtained.

[0025] According to the present invention, a positive electrode for a lithium-air battery with improved mechanical properties, such as tensile strength, can be obtained by means of a fibrous filler.

[0026] According to the present invention, a positive electrode for a lithium-air battery can be obtained that has excellent mechanical properties and can maintain its structure even when expanded by discharge products.

[0027] According to the present invention, a positive electrode for a lithium-air battery can be obtained that has excellent mechanical properties and is advantageous for large-area fabrication.

[0028] The effects of the present invention are not limited to those mentioned above. It should be understood that the effects of the present invention include all effects that can be inferred from the following description. Brief explanation of the drawing

[0029] FIG. 1 is a cross-sectional view illustrating a lithium-air battery according to the present invention. FIG. 2 illustrates a positive electrode for a lithium-air battery according to the present invention. FIG. 3 is a flowchart illustrating a method for manufacturing an anode according to the present invention. Figure 4 is a scanning electron microscope (SEM) analysis result of bundled carbon nanotubes used in an embodiment according to the present invention. Figure 5a is a scanning electron microscope (SEM) analysis result of the positive electrode for a lithium-air battery according to Example 2 of the present invention. Figure 5b is the result of performing scanning electron microscope (SEM) analysis after generating a discharge product on the anode of Figure 5a. Figure 6a is a scanning electron microscope (SEM) analysis result of the positive electrode for a lithium-air battery of Comparative Example 1 according to the present invention. Figure 6b is the result of performing scanning electron microscope (SEM) analysis after generating a discharge product on the anode of Figure 6a. Specific details for implementing the invention

[0030] The above objects, other objects, features, and advantages of the present invention will be easily understood through the following preferred embodiments associated with the accompanying drawings. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided to ensure that the disclosed content is thorough and complete, and to ensure that the spirit of the invention is sufficiently conveyed to a person skilled in the art.

[0031] In describing each drawing, similar reference numerals have been used for similar components. In the attached drawings, the dimensions of the structures are depicted enlarged from their actual size for clarity of the invention. Terms such as "first," "second," etc., may be used to describe various components, but said components should not be limited by said terms. These terms are used solely for the purpose of distinguishing one component from another. For example, without departing from the scope of the invention, the first component may be named the second component, and similarly, the second component may be named the first component. A singular expression includes a plural expression unless the context clearly indicates otherwise.

[0032] In this specification, terms such as "comprising" or "having" are intended to specify the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof. Furthermore, when a part such as a layer, film, region, or plate is described as being "on" another part, this includes not only the case where it is "immediately above" the other part, but also the case where there is another part in between. Conversely, when a part such as a layer, film, region, or plate is described as being "below" another part, this includes not only the case where it is "immediately below" the other part, but also the case where there is another part in between.

[0033] Unless otherwise specified, all numbers, values, and / or expressions used herein to represent amounts of ingredients, reaction conditions, polymer compositions, and formulations should be understood to be modified by the term “approximately” in all cases, as these numbers are essentially approximations reflecting the various uncertainties of measurement that occur in obtaining these values ​​among other things. Furthermore, where numerical ranges are disclosed herein, such ranges are continuous and, unless otherwise indicated, include all values ​​from the minimum value of such range to the maximum value including said maximum value. Moreover, where such ranges refer to integers, they include all integers from the minimum value to said maximum value including said maximum value, unless otherwise indicated.

[0035] FIG. 1 is a cross-sectional view illustrating a lithium-air battery (1) according to the present invention. Referring thereto, the lithium-air battery (1) comprises a positive electrode (10), a negative electrode (20), and an electrolyte (30) charged between the positive electrode (10) and the negative electrode (20) or impregnated in one or more of the electrodes.

[0036] FIG. 2 schematically illustrates an anode (10) according to the present invention. Referring thereto, the anode (10) may include a sheet layer (11) containing bundle-type carbon nanotubes (11a) and a fibrous filler (13) that is intertwined with the bundle-type carbon nanotubes (11a) within the sheet layer (11).

[0037] The sheet layer (11) may have a mesh structure formed by bundled carbon nanotubes (11a) intertwined with each other, as shown in FIG. 2. Here, the mesh structure may refer to a shape formed by bundled carbon nanotubes (11a) intertwined randomly with each other.

[0038] The bundled carbon nanotube (11a) above may be composed of a plurality of carbon nanotube units (11b) aggregated as shown in FIG. 2.

[0039] The carbon nanotube unit (11b) is a type of carbon allotrope in which carbon atoms are bonded in a hexagonal honeycomb shape to form a tube shape, and the diameter may be extremely small at the nanometer level. Specifically, the carbon nanotube unit (11b) may have a diameter of 10 nm to 50 nm. In addition, the carbon nanotube unit (11b) may have a length of 100 nm to 5 µm.

[0040] The carbon nanotube unit (11b) is an excellent electrical and thermal conductor and is a high-strength and high-elasticity material based on a graphite crystal structure, having a high specific surface area due to its nanostructure. Specifically, the carbon nanotube unit (11b) has a specific surface area of ​​150 m² 2 / g to 300m 2 It could be / g.

[0041] The carbon nanotube unit (11b) may be a single-walled carbon nanotube (SWCNT), a double-walled carbon nanotube (DWCNT), or a multi-walled carbon nanotube (MWCNT) depending on the number of walls made of graphite planes.

[0042] The present invention is characterized by forming the sheet layer (11) with bundled carbon nanotubes (11a) aggregated from the carbon nanotube units (11b) rather than the carbon nanotube units (11b). The bundled carbon nanotubes (11a) may be advantageous for forming a two-dimensional sheet layer (11) compared to the carbon nanotube units (11b).

[0043] The bundled carbon nanotube (11a) may have a diameter of 2 µm to 10 µm. Additionally, the bundled carbon nanotube (11a) may have a length of 50 µm to 100 µm.

[0044] Meanwhile, when the anode (10) is composed solely of the bundled carbon nanotubes (11a), the bundled carbon nanotubes (11a) are densely stacked, making it difficult to sufficiently increase the porosity of the anode (10), and consequently, there may be limitations in realizing a high-capacity lithium-air battery.

[0045] Accordingly, the present invention is characterized by increasing the porosity of the anode (10) by inserting a fibrous filler (13) into a sheet layer (11) containing the bundled carbon nanotubes (11a). Because the bundled carbon nanotubes (11a) are not entangled too tightly by the fibrous filler (13), the porosity can be sufficiently increased.

[0046] In addition, the fiber-type filler (13) functions as a type of support within the sheet layer (11). Therefore, according to the present invention, the anode (10) can be constructed without using a binder. Consequently, problems such as increased cell resistance and deterioration of the anode caused by the binder can be resolved.

[0047] In addition, the present invention uses an electrically conductive material as the fibrous filler (13), thereby further increasing the electrical conductivity within the anode (10). Specifically, the fibrous filler (13) may include at least one selected from the group consisting of carbon fiber, carbon nanofiber, vapor grown carbon fiber (VGCF), silver wire, stainless wire, platinum wire, and combinations thereof.

[0048] The fiber-type filler (13) for implementing the above effect may have a length of 1 mm to 10 mm.

[0049] The anode (10) may comprise 95% to 98% by weight of the bundled carbon nanotubes (11a) and 2% to 5% by weight of the fiber-type filler (13). If the content of the fiber-type filler (13) exceeds 5% by weight, the content of the bundled carbon nanotubes (11a) is relatively lower, which may reduce the capacity of the battery. Conversely, if the content of the fiber-type filler (13) is less than 2% by weight, the porosity of the anode (10) may be lowered, making it difficult for oxygen to enter, and the mechanical properties of the anode (10) may be degraded.

[0050] The anode (10) configured as above may have a porosity of 75% to 90%.

[0051] The above-mentioned cathode (20) is a portion capable of absorbing and releasing lithium (Li), and is configured to release lithium ions during discharge and receive lithium ions during charging.

[0052] The above-mentioned cathode (20) may include lithium metal or a lithium metal-based alloy. The alloy may be an alloy of at least one metal selected from the group consisting of lithium and sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), francium (Fr), beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), radium (Ra), aluminum (Al), tin (Sn), and combinations thereof.

[0053] The above electrolyte (30) is typically provided between the anode (10) and the cathode (20), but due to the nature of the electrolyte being a liquid rather than a solid, it is also possible for the electrolyte (30) to exist in a form in which part or all of it is impregnated into the anode (10) and / or the cathode (20). Additionally, if a separator (not shown) is present, it may also exist in a form in which it is impregnated into the separator.

[0054] The above electrolyte (30) may include a lithium salt. The lithium salt is dissolved in a solvent and may serve as a source of lithium ions or promote the movement of lithium ions within the battery.

[0055] The above lithium salt may include at least one selected from the group consisting of LiPF6, LiBF4, LiSbF6, LiAsF6, LiN(SO2C2F5)2, Li(CF3SO2)2N, LiC4F9SO3, LiClO4, LiAlO2, LiAlCl4, LiF, LiBr, LiCl, LiI, LiB(C2O4)2, LiCF3SO3, LiN(SO2CF3)2(LiTFSI), LiN(SO2C2F5)2, LiC(SO2CF3)3, and combinations thereof.

[0056] Meanwhile, the above electrolyte (30) may be classified into an aqueous electrolyte or a non-aqueous electrolyte depending on the type of solvent. Specifically, the above aqueous electrolyte may be in the form of containing the lithium salt in water, and the above non-aqueous electrolyte may be in the form of containing the lithium salt in an organic solvent.

[0057] The above organic solvent may include at least one selected from the group consisting of carbonate-based, ester-based, ether-based, ketone-based, organosulfur-based, organophosphorous-based, aprotic solvents, and combinations thereof.

[0058] The lithium-air battery (1) according to the present invention may further include a separator (not shown) provided between the positive electrode (10) and the negative electrode (20). Any separator capable of separating or insulating the positive electrode (10) and the negative electrode (20) from each other and allowing only lithium ions to pass through while blocking other substances may be used without limitation. For example, a polymer nonwoven fabric such as a polypropylene nonwoven fabric or a polyphenylene sulfide nonwoven fabric, or a porous film of an olefin resin such as polyethylene or polypropylene may be used.

[0060] FIG. 3 is a flowchart illustrating a method for manufacturing an anode according to the present invention. Referring thereto, the manufacturing method may include the step of preparing a solution by dispersing bundle-type carbon nanotubes and fiber-type fillers in a solvent (S10), the step of filtering the solution (S20), and the step of pressurizing the filtered product (S30).

[0061] As the bundled carbon nanotubes and fiber-type fillers mentioned above have been described above, they will be omitted below.

[0062] The above solution can be prepared by mixing the bundled carbon nanotubes and the fiber-type filler to prepare a paste, and then dispersing the paste in a solvent.

[0063] The above solvent is not particularly limited, and, for example, an aqueous solvent may be used.

[0064] In addition, the above solution can be irradiated with ultrasound to uniformly disperse the paste, specifically the bundled carbon nanotubes and fiber-type fillers. The conditions for the ultrasound irradiation are not particularly limited, and ultrasound having a frequency that does not affect the paste can be irradiated, while irradiating for a duration sufficient to ensure that the paste is sufficiently uniformly dispersed.

[0065] Subsequently, the above solution can be filtered. The filtered result may include the sheet layer and a fibrous filler present inside the sheet layer.

[0066] Through the above filtration, the bundled carbon nanotubes become entangled with each other, forming a sheet layer having a mesh structure. Specifically, when the bundled carbon nanotubes are introduced into an aqueous solvent, hydrogen bonding is formed between the bundled carbon nanotubes, and as the aqueous solvent is removed through filtration, Van der Waals forces are generated between the bundled carbon nanotubes, thereby forming a sheet layer having a mesh structure.

[0067] Meanwhile, during the filtration process, the bundled carbon nanotubes form a mesh structure, and at the same time, the fibrous filler is inserted between the bundled carbon nanotubes to serve as a support. In addition, since the fibrous filler prevents the bundled carbon nanotubes from being stacked too densely, the porosity of the sheet layer can be increased to an appropriate level.

[0068] Subsequently, the filtered product can be dried to completely remove the solvent. The filtered and dried product can be pressurized to obtain a high-density anode.

[0070] Other forms of the present invention will be described in more detail through the following examples. The following examples are merely illustrative to aid in understanding the present invention and do not limit the scope of the present invention.

[0072] Examples 1 to 3

[0073] A paste was prepared by mixing bundled carbon nanotubes and carbon fibers. Figure 4 is a scanning electron microscope (SEM) image of the bundled carbon nanotubes. At this time, the content of the bundled carbon nanotubes was adjusted to 2 wt% (Example 1), 3 wt% (Example 2), and 4 wt% (Example 3), respectively. In addition, the bundled carbon nanotubes used had an average diameter of 2 to 4 μm and a length of 60 to 80 μm, and the carbon fibers used had a length of 3 mm.

[0074] The above paste was added to water, an aqueous solvent. Ultrasound was applied to the resulting product to obtain a solution in which the paste was evenly dispersed in the water.

[0075] The above solution was filtered through a glass fiber filter to remove the solvent. The filtered product was separated from the glass fiber filter and dried to remove all residual solvent.

[0076] The filtered product was subjected to heat and pressure to obtain a high-density cathode for a lithium-air battery. The carbon loading amount of the cathode was approximately 10 mg / cm². 2 It was adjusted to this, and its thickness was about 200㎛.

[0078] Comparative Example 1

[0079] A cathode for a lithium-air battery was manufactured in the same manner as in the above example, except that carbon fibers were not used. That is, the cathode according to Comparative Example 1 is composed solely of bundled carbon nanotubes.

[0081] Comparative Example 2

[0082] A positive electrode for a lithium-air battery was prepared in the same manner as in Example 3 above, except that 4% by weight of polytetrafluoroethylene (PTFE), a polymer binder, was used instead of carbon fiber.

[0084] Experimental Example

[0085] The tensile strength, surface resistance, and porosity of the cathodes for lithium-air batteries according to Examples 1 to 3 and Comparative Examples 1 and 2 were measured. The tensile strength was measured in accordance with ASTM D882-10 using a micro tensile testing machine (BT1-FPLV.00, Zwick / Roell, Germany) equipped with a 500N load cell, the surface resistance was measured using the 4-point probe method, and the porosity was measured using an Hg Prosimeter. The results are shown in Table 1 below.

[0086] Meanwhile, a lithium-air battery was manufactured according to Examples 1 to 3 and Comparative Examples 1 and 2, comprising an anode, a cathode, a separator located between the anode and the cathode, and an electrolyte impregnated in the separator. Lithium metal was used as the cathode, and 1M LiNO3 in DMAc was used as the electrolyte. The discharge capacity of each lithium-air battery was measured. The discharge capacity was measured under a 100% oxygen (O2) atmosphere, a pressure of 2 bar, and 0.5 mA / cm². 2 It was measured under the condition of current density. The results are as shown in Table 1 below.

[0087] division Comparative Example 1 Example 1 Example 2 Example 3 Comparative Example 2 Tensile strength [Mpa] 3 8 10 14 17 Surface resistance [Ω / sq.] 0.7 1.2 2.5 4 12 Porosity[%] 71 76 81 84 68 Discharge capacity [mAh / cm²] 2 ] 19 21 25 23 20

[0088] Referring to Table 1, Comparative Example 1 above consists only of bundled carbon nanotubes, so the surface resistance is the lowest, but the porosity is too low, making it difficult for oxygen to enter, so the discharge capacity is low.

[0089] In addition, Comparative Example 2 has excellent tensile strength, but the polymer binder polytetrafluoroethylene (PTFE) acts as a resistance, resulting in high surface resistance and very low porosity.

[0090] Meanwhile, the above Examples 1 to 3 have superior tensile strength compared to Comparative Example 1, very low surface resistance compared to Comparative Example 2, and high porosity and discharge capacity compared to Comparative Examples 1 and 2. Therefore, it can be seen that according to the present invention, a lithium-air battery with excellent mechanical properties, low cell resistance, and high porosity and discharge capacity can be obtained.

[0091] Scanning electron microscope (SEM) analysis was performed on the cathodes for lithium-air batteries according to Example 2 and Comparative Example 1 above.

[0092] FIG. 5a is a result for a positive electrode for a lithium-air battery according to Example 2 above, and FIG. 5b is a result for the positive electrode in a state where a discharge product is formed. FIG. 6a is a result for a positive electrode for a lithium-air battery according to Comparative Example 1 above, and FIG. 6b is a result for the positive electrode in a state where a discharge product is formed.

[0093] Referring to FIG. 5a, the anode according to the present invention comprises a sheet layer composed of bundled carbon nanotubes and a fibrous filler inserted inside the sheet layer. Referring to FIG. 5b, the anode according to the present invention has a discharge product formed uniformly inside it without cracking.

[0094] Meanwhile, referring to Fig. 6a, the anode according to Comparative Example 1 is composed only of bundled carbon nanotubes, so no fibrous filler is found. Referring to Fig. 6b, it can be seen that cracks occur in the anode according to Comparative Example 1 due to the formation of discharge products within it.

[0096] As the experimental examples and embodiments of the present invention have been described in detail above, the scope of the present invention is not limited to the aforementioned experimental examples and embodiments, and various modifications and improvements by those skilled in the art using the basic concept of the present invention as defined in the following claims are also included within the scope of the present invention. Explanation of the symbols

[0097] 1: Lithium-air battery 10: Negative electrode 20: Positive electrode 30: Electrolyte 11: Sheet layer 11a: Bundle-type carbon nanotubes 11b: Carbon nanotube monomer 13: Fibrous filler

Claims

Claim 1 A positive electrode for a lithium-air battery comprising: a sheet layer having a mesh structure formed by the bundle-type carbon nanotubes intertwining with each other; and a fibrous filler existing intertwined with the bundle-type carbon nanotubes within the sheet layer and having electrical conductivity; wherein the bundle-type carbon nanotubes comprise 95% to 98% by weight; and the fibrous filler comprises 2% to 5% by weight; and wherein the bundle-type carbon nanotubes have a diameter of 2㎛ to 10㎛. Claim 2 A positive electrode for a lithium-air battery according to claim 1, wherein the bundled carbon nanotube is formed by aggregating a plurality of carbon nanotube units, and the carbon nanotube units have a diameter of 10 nm to 50 nm. Claim 3 In paragraph 2, the carbon nanotube unit is a positive electrode for a lithium-air battery having a length of 100 nm to 5 µm. Claim 4 In paragraph 2, the carbon nanotube monomer has a specific surface area of ​​150 m² 2 / g to 300m 2 A positive electrode for a lithium-air battery that is / g. Claim 5 delete Claim 6 A positive electrode for a lithium-air battery according to claim 1, wherein the bundled carbon nanotube has a length of 50 μm to 100 μm. Claim 7 The cathode for a lithium-air battery according to claim 1, wherein the fiber-type filler comprises at least one selected from the group consisting of carbon fiber, carbon nanofiber, vapor-grown carbon fiber (VGCF), silver wire, stainless steel wire, platinum wire, and combinations thereof. Claim 8 In claim 1, the fibrous filler is a positive electrode for a lithium-air battery having a length of 1 mm to 10 mm. Claim 9 delete Claim 10 A positive electrode for a lithium-air battery having a porosity of 75% to 90% in claim 1. Claim 11 A method for manufacturing a positive electrode for a lithium-air battery, comprising the steps of: preparing a solution by dispersing bundle-type carbon nanotubes and a fibrous filler in a solvent; and filtering the solution; wherein the filtered result comprises a sheet layer having a mesh structure formed by the bundle-type carbon nanotubes intertwining with each other; and a fibrous filler existing intertwined with the bundle-type carbon nanotubes within the sheet layer and having electrical conductivity; wherein the composition comprises 95% to 98% by weight of the bundle-type carbon nanotubes; and 2% to 5% by weight of the fibrous filler; wherein the bundle-type carbon nanotubes have a diameter of 2㎛ to 10㎛. Claim 12 A method for manufacturing a positive electrode for a lithium-air battery according to claim 11, wherein the above-mentioned bundled carbon nanotubes and fiber-type fillers are mixed to produce a paste, and the above-mentioned paste is dispersed in a solvent to prepare the above-mentioned solution. Claim 13 A method for manufacturing a positive electrode for a lithium-air battery according to claim 11, wherein the bundled carbon nanotubes and fiber-type filler are dispersed by irradiating the above solution with ultrasound. Claim 14 A method for manufacturing a positive electrode for a lithium-air battery according to claim 11, further comprising the step of pressurizing the filtered product. Claim 15 In claim 11, the bundled carbon nanotube is an aggregate of a plurality of carbon nanotube units, wherein the carbon nanotube units have a diameter of 10 nm to 50 nm, a length of 50 µm to 100 µm, and a specific surface area of ​​150 m² 2 / g to 300m 2 A method for manufacturing a positive electrode for a lithium-air battery that is / g. Claim 16 A method for manufacturing a positive electrode for a lithium-air battery according to claim 11, wherein the bundled carbon nanotubes have a length of 50 μm to 100 μm. Claim 17 A method for manufacturing a positive electrode for a lithium-air battery according to claim 11, wherein the fiber-type filler comprises at least one selected from the group consisting of carbon fiber, carbon nanofiber, vapor-grown carbon fiber (VGCF), silver wire, stainless steel wire, platinum wire, and combinations thereof. Claim 18 A method for manufacturing a positive electrode for a lithium-air battery according to claim 11, wherein the fiber-type filler has a length of 1 mm to 10 mm. Claim 19 delete Claim 20 In claim 11, a method for manufacturing a positive electrode for a lithium-air battery having a porosity of 75% to 90%.

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