KR102572838B1 - cathode material for metal-air bettery and manufacturing method thereof - Google Patents

Abstract

The present invention relates to a cathode material for a metal-air battery and a method for manufacturing the same, and more particularly, a metal-air battery using the cathode material for a metal-air battery of the present invention has excellent charge/discharge characteristics and lifespan characteristics, and manufacturing thereof It's about how.

Description

Cathode material for metal-air battery and manufacturing method thereof

The present invention relates to a cathode material for a metal-air battery and a method for manufacturing the same, and more particularly, a metal-air battery using the cathode material for a metal-air battery of the present invention has excellent charge/discharge characteristics and lifespan characteristics, and manufacturing thereof It's about how.

Carbon black is widely used as a black pigment and as a reinforcing agent and filler. Carbon black is produced with different properties by different methods. The most common method is a production method by oxidative pyrolysis of a carbon-containing carbon black raw material. In this case, the carbon black raw material is incompletely burned in the presence of oxygen at high temperature. Examples of this class of carbon black production process include the furnace black process, the gas black process and the lamp black process. Examples of other methods include an acetylene method, a thermal black method, and a plasma method.

In addition, carbon black is used as a conductive material for manganese batteries, lithium batteries, secondary batteries, etc. due to its high conductivity, and it is known that the more micropores in the carbon black aggregate, the greater the capacity. Research is being conducted targeting large-sized batteries. , In fuel cells, it is used as a catalyst carrier for the catalyst layer, and studies are being conducted to control the specific surface area of carbon black in order to reduce the amount of expensive platinum catalyst added and increase the active area. For example, various attempts have been made, such as forming pores by chemically activating the surface of carbon black or increasing energy storage by maintaining conductivity by introducing a mixed secondary structure between carbon blacks.

Meanwhile, a metal-air battery uses a transition metal for an anode and oxygen in the air as a cathode active material. In addition, the metal-air battery generates electricity by reacting transition metal ions of the negative electrode with oxygen, and unlike conventional secondary batteries, it is not necessary to have a positive electrode active material inside the battery in advance, so it can be lightweight. In addition, since a large amount of negative electrode material can be stored in the container, it can theoretically exhibit a large capacity and high energy density.

A metal-air battery includes a negative electrode capable of intercalating/extracting transition metal ions, a positive electrode including an oxygen oxidation-reduction catalyst using oxygen in the air as a positive electrode active material, and an electrolyte as a transition metal ion conductive medium between the positive electrode and the negative electrode. do.

Important factors that determine the electrochemical properties of a metal-air battery may include an electrolyte system, anode structure, excellent air cathode catalyst, type of carbon support, and oxygen pressure. During discharge, transition metal ions generated from the cathode meet oxygen at the anode to produce transition metal oxides, and oxygen is reduced (oxygen reduction reaction: ORR). Conversely, during charging, transition metal oxides are reduced and oxygen is oxidized (oxygen evolution reaction: OER). The air electrode catalyst of the metal-air battery performs functions such as increasing the specific energy capacity of the battery, reducing the overvoltage of the battery, and improving the charging/discharging characteristics of the battery. In a metal-air battery, overvoltage is applied because it is difficult to oxidize precipitated transition metal oxides during charging. To reduce this, a metal catalyst (Pt, Au, Ag, etc.) is used as a catalyst for an air electrode. In particular, it is known that when an alloy between metals with excellent performance is used as an air electrode catalyst, the charge/discharge efficiency can be further increased by the alloy nanoparticles serving as a bi-functional catalyst. In addition, when a metal catalyst such as manganese is uniformly dispersed and supported on a carbon support, the performance as an air electrode catalyst can be maximized by combining the large surface area and electrical conductivity of carbon with the metal catalytic ability.

Further, among metal-air batteries, lithium-air batteries are typically used. It is known that a lithium-air battery is generally provided with a negative electrode capable of intercalating / releasing lithium ions, a positive electrode (air electrode) in which oxygen is used as an active material and oxygen reduction and oxidation reactions occur, an electrolyte solution, and a separator between the negative electrode and the positive electrode. . In such a lithium-air battery, lithium ions and electrons are generated by an oxidation reaction of a negative electrode capable of intercalating/discharging lithium ions during discharge, and the generated lithium ions move through an electrolyte, and the electrons move along an external conductor to the positive electrode (air electrode). ) will move to Oxygen contained in the outside air flows into the anode (air cathode) and produces by-products such as Li ₂ O ₂ . During charging, the opposite reaction proceeds. As such, the lithium-air battery has a problem in that cycle life characteristics are deteriorated while passing through the above reactions during charging and discharging.

Korean Patent Publication No. 10-2014-0087393 (published on July 9, 2014) Korean Patent Publication No. 10-2019-0017097 (published on 2019.02.20) Korean Patent Publication No. 10-2018-0034120 (published on 2018.04.04)

As a result of repeated studies on the control of the specific surface area of carbon black, the present inventors found that it was possible to produce hollow carbon black with significantly increased micropore volume and increased specific surface area of furnace carbon black among carbon blacks. In addition, in a specific manufacturing process, it has been found that a plurality of hollow carbon blacks are combined and integrated to form a tunnel by connecting empty spaces inside the combined carbon black, that is, internal pores.

As described above, the present invention is a metal air containing a positive electrode active material containing at least one selected from microporous hollow furnace carbon black and microporous hollow furnace carbon black composite having a significantly increased specific surface area and micropore volume compared to raw carbon black. It is intended to provide a cathode material for a battery and a manufacturing method thereof.

In order to solve the above problems, the manufacturing method of a positive electrode material for a metal-air battery of the present invention is a first step of preparing a positive electrode active material containing at least one selected from microporous hollow furnace carbon black and microporous hollow furnace carbon black assembly. A step, a second step of preparing a cathode reactant by mixing the cathode active material and a binder, and a third step of preparing a cathode material for a metal-air battery by coating the cathode reactant on a surface of a metal foil and then drying it.

In a preferred embodiment of the present invention, the cathode reactant may be a mixture of 70 to 95 wt% of the cathode active material and 5 to 30 wt% of the binder, based on the total weight%.

In a preferred embodiment of the present invention, the microporous hollow furnace carbon black of the present invention is a furnace carbon black prepared by carrying out a gas phase oxidation reaction of furnace carbon black using an oxidizing gas, and has a hollow structure, may have gaps.

In a preferred embodiment of the present invention, the microporous hollow carbon black of the present invention may have a micropore volume that satisfies Equation 1 below.

[Equation 1]

2.0 ≤ B/A ≤ 7.0

In Equation 1, A is the micropore volume of the furnace carbon black before the gas phase oxidation reaction is performed, and B is the micropore volume of the furnace carbon black after the gas phase oxidation reaction is performed.

In a preferred embodiment of the present invention, the microporous hollow carbon black of the present invention may have a BET specific surface area of 180 to 1,200 m ² /g.

In a preferred embodiment of the present invention, the microporous hollow carbon black of the present invention may have a total pore volume of 0.190 to 1.200 cm ³ /g.

In a preferred embodiment of the present invention, the microporous hollow carbon black of the present invention may have an average micro pore diameter of 4.0 to 8.0 nm.

In a preferred embodiment of the present invention, the microporous hollow furnace carbon black assembly of the present invention includes one or more combined bodies in which a plurality of microporous hollow carbon blacks are combined and integrated, and the plurality of microporous hollow carbon blacks are integrated. Each pore hollow furnace carbon black has a hollow structure and has a plurality of micro-sized pores, and the combination is formed by interconnecting internal pores in all or part of the plural micro-porous hollow furnace carbon blacks to form a hollow hollow furnace carbon black. It may be forming an internal tunnel in the furnace carbon black assembly.

In a preferred embodiment of the present invention, the microporous hollow furnace carbon black assembly of the present invention may have a mesopore volume that satisfies Equation 2 below.

[Equation 2]

3.0 ≤ B/A ≤ 8.0

In Equation 2, A is the mesopore volume of the furnace carbon black before the gas phase oxidation reaction is performed, and B is the mesopore volume of the conjugate formed after the gas phase oxidation reaction is performed.

In a preferred embodiment of the present invention, the conjugate may have a BET specific surface area of 400 to 1,000 m ² /g.

In a preferred embodiment of the present invention, the conjugate may have a total pore volume of 0.550 to 1.500 cm ³ /g.

In a preferred embodiment of the present invention, the micro-porous hollow carbon black constituting the composite may have an average micro-pore diameter of 4.0 to 8.0 nm.

On the other hand, the method for producing microporous hollow carbon black of the present invention includes a first-first step of preparing furnace carbon black and a first-second step of performing a gas phase oxidation reaction of the furnace carbon black using CO ₂ , an oxidizing gas. can include

In a preferred embodiment of the present invention, the micropore volume of the furnace carbon black subjected to gas phase oxidation in the first and second stages of the method for producing microporous hollow carbon black of the present invention may satisfy Equation 1 below.

[Equation 1]

2.0 ≤ B/A ≤ 7.0

In Equation 1, A is the micropore volume of the furnace carbon black before the gas phase oxidation reaction is performed, and B is the micropore volume of the furnace carbon black after the gas phase oxidation reaction is performed.

In a preferred embodiment of the present invention, the gas phase oxidation reaction of the first and second steps of the method for producing microporous hollow carbon black of the present invention is carried out in an oxidation chamber, and the oxidation reaction is performed at 850 ° C to 1200 ° C. It may be performed for 30 minutes to 150 minutes while supplying gas in the oxidation chamber.

In a preferred embodiment of the present invention, the oxidizing gas in the first and second steps of the method for producing microporous hollow carbon black of the present invention may contain 99.000 to 99.999 vol% of CO ₂ .

As a preferred embodiment of the present invention, the gas phase oxidation reaction of the first and second steps of the method for producing microporous hollow carbon black of the present invention can be performed while supplying an oxidizing gas into the oxidation chamber at 50 to 200 mL/min. there is.

Furthermore, the manufacturing method of the microporous hollow carbon black assembly of the present invention includes a first-first step of preparing furnace carbon black, a first-second step of performing a gas phase oxidation reaction on the furnace carbon black using an oxidizing gas, and Steps 1 to 3 of separating an assembly in which a plurality of hollow carbon blacks are bonded from the gas phase oxidation reactant may be included.

In a preferred embodiment of the present invention, the gas phase oxidation reaction of the first and second steps of the manufacturing method of the microporous hollow carbon black assembly of the present invention is performed in an oxidation chamber and oxidizes an oxidizing gas at 900 to 1,300 ° C. While feeding in the chamber, it can be performed for 80 to 150 minutes.

In a preferred embodiment of the present invention, the oxidizing gas in the first and second steps of the method for manufacturing a microporous hollow carbon black assembly of the present invention may contain 99.000 to 99.999 vol% of CO ₂ .

In a preferred embodiment of the present invention, the gas phase oxidation reaction of the first and second steps of the method for manufacturing a microporous hollow carbon black assembly of the present invention is performed while supplying an oxidizing gas into the oxidation chamber at 150 to 300 mL/min. can do.

In a preferred embodiment of the present invention, each of the plurality of hollow furnace carbon blacks constituting the assembly of the first to third steps of the manufacturing method of the microporous hollow carbon black assembly of the present invention has a hollow structure, and a plurality of microporous carbon blacks It can have voids of any size.

In a preferred embodiment of the present invention, the assembly of the manufacturing method of the microporous hollow carbon black assembly of the present invention is integrated by combining a plurality of microporous hollow carbon blacks, and the plurality of microporous hollow carbon blacks are combined. Internal pores in all or part of the furnace carbon black may be connected to each other to form an internal tunnel in the hollow furnace carbon black assembly.

In a preferred embodiment of the present invention, the assembly of the manufacturing method of the microporous hollow carbon black assembly of the present invention may include one or more internal tunnels.

In a preferred embodiment of the present invention, the mesopore volume of the assembly in the first to third steps of the manufacturing method of the microporous hollow carbon black assembly of the present invention may satisfy Equation 2 below.

[Equation 2]

3.0 ≤ B/A ≤ 8.0

In Equation 2, A is the mesopore volume of the furnace carbon black before the gas phase oxidation reaction is performed, and B is the mesopore volume of the conjugate formed after the gas phase oxidation reaction is performed.

Meanwhile, the cathode material for a metal-air battery of the present invention includes a metal foil and an anode reactant formed on the surface of the metal foil.

In a preferred embodiment of the present invention, the cathode reactant may include a cathode active material including at least one selected from microporous hollow furnace carbon black and microporous hollow furnace carbon black assembly, and a binder.

In a preferred embodiment of the present invention, the cathode reactant of the cathode material for a metal-air battery of the present invention may include 70 to 95 wt% of the cathode active material and 5 to 30 wt% of the binder with respect to the total weight%.

Furthermore, the metal-air battery of the present invention may include the above-mentioned positive electrode material for metal-air battery, negative electrode material for metal-air battery, electrolyte solution, and separator.

The microporous hollow furnace carbon black and/or the microporous hollow furnace carbon black composite used as the cathode active material of the cathode material for a metal-air battery of the present invention has pores at least twice as much as at most eight times that of furnace carbon black before gas phase oxidation. ) volume increases, and as a result, a metal air battery using a positive electrode material for a metal air battery having a high specific surface area and a high pore volume, and including such a microporous hollow furnace carbon black and / or a porous hollow furnace carbon black combination, is charged and discharged. It has excellent characteristics (charge/discharge capacity, charge/discharge cycle, charge/discharge efficiency, etc.).

1 is a schematic diagram of an oxidation chamber used for a gas phase oxidation reaction in the present invention.
2 is a schematic diagram for explaining the structural differences between porous carbon black before gas-phase oxidation reaction, micro-porous hollow carbon black formed after gas-acid oxidation reaction, and micro-porous hollow furnace carbon black assembly (assembly).
3A to 3D are TEM measurement photographs of microporous hollow furnace carbon black prepared by gas phase oxidation at 1,000° C. for different reaction times.
4a to 4c are TEM measurement photographs of microporous hollow furnace carbon black prepared by performing gas phase oxidation at 1,000 °C for different reaction times.

Hereinafter, with reference to the accompanying drawings, embodiments of the present invention will be described in detail so that those skilled in the art can easily carry out the present invention. This invention may be embodied in many different forms and is not limited to the embodiments set forth herein. In order to clearly describe the present invention in the drawings, parts irrelevant to the description are omitted, and the same reference numerals are added to the same or similar components throughout the specification.

The method for manufacturing a cathode material for a metal-air battery of the present invention includes first to third steps.

In the first step of the method of manufacturing a cathode material for a metal-air battery of the present invention, a cathode active material may be prepared. In this case, the cathode active material may include at least one selected from microporous hollow furnace carbon black and microporous hollow furnace carbon black assembly, and specifically, may include only microporous hollow furnace carbon black, and microporous hollow furnace carbon black. It may include only porous hollow furnace carbon black assemblies, or may include a mixture of micro porous hollow furnace carbon black and micro porous hollow furnace carbon black assemblies.

First, the microporous hollow furnace carbon black that can be used as a cathode active material includes a first-first step of preparing the furnace carbon black and a first-second step of performing a vapor phase oxidation reaction of the furnace carbon black using CO ₂ , an oxidizing gas. It can be prepared including steps.

In the production of microporous hollow furnace carbon black, commercially available furnace carbon black may be used as the furnace carbon black in the 1-1 step, and preferably a commercial name of Super-p and Furnace carbon black containing at least one selected from the trade name C-NERGY may be used.

In addition, in the production of microporous hollow furnace carbon black, the gas phase oxidation reaction of the first and second steps may be performed in an oxidation chamber schematically shown in FIG. 1, after introducing the furnace carbon black into the oxidation chamber, The gas phase oxidation reaction may be performed while supplying gas into the oxidation chamber.

In addition, in the production of microporous hollow furnace carbon black, the gas phase oxidation reaction of the first and second steps can be performed for 30 minutes to 150 minutes at 850 ° C to 1200 ° C while supplying an oxidizing gas in an oxidation chamber, , Preferably at 900 ° C to 1150 ° C for 40 minutes to 120 minutes, more preferably at 950 ° C to 1100 ° C for 45 minutes to 110 minutes. If the gas phase oxidation reaction temperature is less than 850° C. or the gas phase oxidation reaction time is less than 30 minutes, there may be problems in that the specific surface area, micropore volume, and total pore volume of the furnace carbon black subjected to the gas phase oxidation reaction are low. In addition, when the gas phase oxidation reaction temperature exceeds 1200 ° C or the gas phase oxidation reaction time exceeds 150 minutes, physical properties such as the specific surface area and micropore volume of carbon black do not increase any more, and pores (voids) are formed. Since the retaining wall becomes thin, the pore shape collapses, the mechanical strength of the carbon black is too low, it is easily broken, and the manufacturing yield is greatly reduced.

In addition, in the production of microporous hollow furnace carbon black, CO ₂ is used as an oxidizing gas in the first and second steps, preferably 99.000 to 99.999% by volume, preferably 99.500 to 99.999% by volume, and more Preferably, 99.800 to 99.999 vol% of CO ₂ is used. The gas phase oxidation reaction may be performed while supplying an oxidizing gas into the oxidation chamber at a flow rate of 50 to 200 mL/min, preferably 80 to 150 mL/min, and more preferably 85 to 120 mL/min.

In addition, the prepared microporous hollow furnace carbon black may have a burn-off yield of 25.0% to 65.0%, preferably 30.0 to 63.0%, and more preferably 35.0 to 55.0%.

In addition, as shown schematically in FIG. 2, the manufactured microporous hollow furnace carbon black has a hollow structure having micropores, unlike carbon black having a conventional porous structure, and has micropores satisfying Equation 1 below. can have volume.

[Equation 1]

2.0 ≤ B/A ≤ 7.0, preferably 2.5 ≤ B/A ≤ 6.8, more preferably 3.0 ≤ B/A ≤ 6.5

In Equation 1, A is the micropore volume of the furnace carbon black before the gas phase oxidation reaction is performed, and B is the micropore volume of the furnace carbon black after the gas phase oxidation reaction is performed.

In addition, the prepared microporous hollow furnace carbon black has a BET specific surface area of 180 to 1,200 m ² /g, preferably a BET specific surface area of 320 to 1,150 m ² /g, more preferably 450 to 820 m ² /g. , more preferably 490 to 750 m ² /g.

In addition, the manufactured microporous hollow furnace carbon black may have a total pore volume of 0.190 to 1.200 cm ³ /g, preferably a total pore volume of 0.300 to 0.950 cm ³ /g, more preferably A total pore volume of 0.500 to 0.800 cm ³ /g may be satisfied.

In addition, the prepared microporous hollow carbon black of the present invention may have an average particle diameter of micropores of 4.0 to 8.0 nm, preferably 4.0 to 6.5 nm, and more preferably 4.2 to 6.0 nm. .

In addition, the prepared microporous hollow carbon black of the present invention may have a fraction (V _micro /V _total X 100%) of 4.0 to 13.6% of the micropore volume (V _micro ) to the total pore volume (V _total ), , preferably 5.0 to 13.6%.

Next, the microporous hollow furnace carbon black assembly that can be used as a cathode active material is a first-first step of preparing furnace carbon black and a first-step oxidation reaction of furnace carbon black using CO ₂ , an oxidizing gas. It may be prepared by including step 2 and steps 1 to 3 of separating a composite in which a plurality of hollow furnace carbon blacks are bonded from gas phase oxidation reactants.

In the manufacture of the microporous hollow furnace carbon black assembly, commercially available furnace carbon black may be used as the furnace carbon black in the 1-1 step, preferably a commercial name Super-p. And furnace carbon black containing at least one selected from C-NERGY, a trade name, may be used.

In addition, in the production of microporous hollow furnace carbon black, the gas phase oxidation reaction of the first and second steps may be performed in an oxidation chamber schematically shown in FIG. 1, and after introducing the furnace carbon black into the oxidation chamber, A gas phase oxidation reaction may be performed while supplying an oxidizing gas into an oxidation chamber.

In addition, in the production of microporous hollow furnace carbon black, the gas phase oxidation reaction of the first and second stages can be performed for 80 to 150 minutes at 900 to 1300 ° C. while supplying an oxidizing gas in the oxidation chamber, , Preferably under 950 ~ 1250 ℃ for 80 minutes to 130 minutes, more preferably under 980 ~ 1200 ℃ can be carried out for 90 minutes to 120 minutes. At this time, if the gas phase oxidation reaction temperature is less than 900 ° C or the gas phase oxidation reaction time is less than 80 minutes, there may be a problem in that the specific surface area and mesopore volume of the furnace carbon black assembly obtained by the gas phase oxidation reaction is low, and the form of the assembly There may be a problem in that the yield of microporous hollow carbon black is low. In addition, when the gas phase oxidation reaction temperature exceeds 1300 ° C or the gas phase oxidation reaction time exceeds 150 minutes, physical properties such as the specific surface area and micropore volume of carbon black do not increase any more, and pores (voids) are formed. Since the retaining wall becomes thin, the pore shape collapses, and the mechanical strength of the carbon black is too low, it is easily broken, so that the yield of the microporous hollow carbon black in the form of an assembly may be greatly reduced. It is good.

In addition, in the production of microporous hollow furnace carbon black, CO ₂ is used as an oxidizing gas in the first and second steps, preferably 99.000 to 99.999% by volume, preferably 99.500 to 99.999% by volume, and more Preferably, 99.800 to 99.999 vol% of CO ₂ is used. The gas phase oxidation reaction may be performed while supplying the oxidizing gas into the oxidation chamber at a flow rate of 150 to 300 mL/min, preferably 150 to 250 mL/min, and more preferably 150 to 200 mL/min.

In addition, the yield of the manufactured microporous hollow furnace carbon black assembly may be 58% to 84%, preferably 60% to 82%, and more preferably 70% to 82%.

In addition, in preparing the microporous hollow furnace carbon black, the vapor phase oxidation reactant in the first and second steps may include a plurality of assemblies in which a plurality of microporous hollow carbon blacks described above are bonded together, A plurality of microporous hollow carbon blacks may be included.

In addition, in the production of microporous hollow furnace carbon black, steps 1-3 are steps of separating the conjugate from the gas-phase oxidation reactants of steps 1-2, through a general physical separation method used in the art. It can be performed, and for example, it can be separated through sieve separation, and in order to maximize the yield of the conjugate when performing such a physical separation method, it is preferable to perform the separation method that minimizes the breakage of the conjugate.

In addition, the manufactured micro-porous hollow furnace carbon black assembly may include a micro-porous hollow-furnace carbon black and an integrated body in which a plurality of the micro-porous hollow furnace carbon blacks are bonded together. Can contain multiple. At this time, each of the plurality of microporous hollow furnace carbon blacks has a hollow structure and has a plurality of micro-sized pores, and the combination is formed in all or part of the combined plurality of microporous hollow furnace carbon blacks. Internal pores may be connected to each other to form internal tunnels in the hollow furnace carbon black assembly (see schematic diagram of FIG. 2).

The conjugate may have a mesopore volume that satisfies Equation 2 below.

[Equation 2]

3.0 ≤ B/A ≤ 5.5, preferably 3.2 ≤ B/A ≤ 5.2, more preferably 3.5 ≤ B/A ≤ 5.0

In Equation 2, A is the mesopore volume of the furnace carbon black before the gas phase oxidation reaction is performed, and B is the mesopore volume of the conjugate formed after the gas phase oxidation reaction is performed.

In addition, the manufactured microporous hollow furnace carbon black assembly may include one or more of the conjugates, and the conjugates have a BET specific surface area of 400 to 1,200 m ² /g, preferably a BET specific surface area of 450 to 1,000. m ² /g, more preferably 540 to 900 m ² /g, and even more preferably 570 to 830 m ² /g.

And, each of the micro-porous hollow furnace carbon black constituting the assembly; Or microporous hollow carbon black other than the conjugate that may be included in the assembly; the average particle diameter of the micropores may be 4.0 to 8.0 nm, preferably 4.0 to 6.5 nm, and more preferably 4.0 to 6.0 nm. can

In the second step of the method of manufacturing a cathode material for a metal-air battery of the present invention, a cathode reactant may be prepared by mixing the cathode active material prepared in the first step with a binder.

At this time, the binder may include at least one selected from polyvinylidene fluoride (PVDF), carboxymethylcellulose (CMC), polyacrylic acid (PAA), and polytetrafluoroethylene (PTFE), preferably poly It may include vinylidene fluoride (PVDF).

In addition, the cathode reactant may be a mixture of 70 to 95 wt% of the cathode active material and 5 to 30 wt% of the binder, preferably 75 to 90 wt% of the cathode active material and 10 to 25 wt% of the binder, based on the total weight%. If the cathode active material is mixed in excess of 95% by weight, the capacity is high, but the bonding force is lowered when manufacturing the cathode material for a metal-air battery, which may cause a short circuit between electrodes. There may be a problem in that the capacity is reduced and the energy efficiency is lowered.

In addition, the cathode active material may include at least one selected from the aforementioned microporous hollow furnace carbon black and microporous hollow furnace carbon black assembly.

In the third step of the method for manufacturing a cathode material for a metal-air battery of the present invention, the cathode reactant prepared in the second step is coated on the surface of the metal foil and then dried to prepare a cathode material for a metal-air battery.

At this time, the metal foil may include any metal as long as it has conductivity, preferably may include at least one selected from copper and aluminum, and more preferably may include copper.

In addition, the third step of drying may be performed in a vacuum atmosphere at a temperature of 80 to 120 ° C, preferably 90 to 110 ° C for 4 to 8 hours, preferably 5 to 7 hours.

Furthermore, the cathode material for a metal-air battery of the present invention includes a metal foil and an anode reactant formed on the surface of the metal foil. At this time, the anode reactant refers to a material that reacts with the anode of the battery.

The cathode reactant may include a cathode active material and a binder. In this case, the cathode active material may include at least one selected from the aforementioned microporous hollow furnace carbon black and microporous hollow furnace carbon black assembly, and the binder may include the aforementioned polyvinylidene fluoride (PVDF), It may include at least one selected from carboxymethyl cellulose (CMC), polyacrylic acid (PAA), and polytetrafluoroethylene (PTFE).

In addition, the cathode reactant may include 70 to 95 wt% of the cathode active material and 5 to 30 wt% of the binder, preferably 75 to 90 wt% of the cathode active material and 10 to 25 wt% of the binder, based on the total weight%.

Meanwhile, the metal-air battery of the present invention may include the aforementioned positive electrode material for metal-air battery, negative electrode material for metal-air battery, electrolyte, and separator of the present invention.

A metal-air battery is a secondary battery that generates power by using metal and air as the cathode and anode of the battery. The basic principle of a metal-air battery is that daffodil ions are generated through a reduction reaction in which electrons are obtained using oxygen in the air at the anode, and hydroxide ions generated at the anode move to the cathode through the electrolyte, and the cathode made of metal It is the principle that electrons are generated through an oxidation reaction with hydroxide ions, and the generated electrons move to the anode to flow current and generate power.

In such a metal-air battery, the positive electrode material for a metal-air battery according to the present invention can be used as a positive electrode, and the negative electrode material for a metal-air battery can be used as a negative electrode. At this time, as the anode material for a metal-air battery, any compound can be used as long as lithium metal generates lithium ions by losing electrons while the battery is discharged, and preferably lithium cobalt oxide (LiCoO ₂ ), lithium iron phosphate (LiFePO ₄ ) and It may include at least one selected from lithium manganese oxide (LiMn ₂ O ₄ ), more preferably lithium cobalt oxide (LiCoO ₂ ).

The electrolyte is a liquid with ion conductivity and serves as a passage for the movement of ions for the reaction between the cathode and anode. Any electrolyte with good ion conductivity and low viscosity can be used, preferably lithium hexafluorophosphate (LiPF ₆ ) , lithium nitrate (LiNO ₃ ) and lithium tetrafluoroborate (LiBF ₄ ).

The separator is a configuration used to prevent contact between the positive electrode material and the negative electrode material, and a polymer membrane that does not conduct electricity may be used, preferably a GF / C glass fiber separator, a polypropylene (PP) separator, and polyethylene ( PE) may include one or more selected from separators.

Hereinafter, the present invention will be described in more detail based on examples. However, the scope of the present invention should not be construed as being limited by the following examples.

[Example]

<Preparation Example 1: Production of porous hollow furnace carbon black>

Preparation Example 1-1: Preparation of microporous hollow furnace carbon black according to reaction time

Furnace carbon black (trade name: Super-P, manufacturer: IMERYS) was prepared as a raw material. Basic physical properties of the prepared furnace carbon black are shown in Table 1 below.

Next, after preheating the horizontal tubular furnace (oxidation chamber) shown in FIG. 1 to 1000 ° C, the raw material is charged into the reaction tube of the oxidation chamber using a quartz boat, and then fixed at 1000 ° C. A gas phase oxidation reaction was performed. An oxidizing gas containing CO ₂ at a concentration of 99.950 vol% as a reactive material was used, and the flow rate of the oxidizing gas was maintained at 100 ml/min using a ball flowmeter. In addition, the reaction time is shown in Table 2 below, and the yield (%), BET specific surface area (m ² /g), MV (micropore volume, cm ³ / g), total pore volume (Total pore volume cm ³ /g) and average pore size (nm) are shown in Table 2 below. In addition, transmission electron microscope (TEM) measurement pictures of each of these are shown in FIGS. 3A to 3D.

Referring to FIG. 3a, in the case of furnace carbon black not subjected to gas phase oxidation treatment, no pores were observed inside, and no pores were developed inside, so it was confirmed that the BET specific surface area was very small at 61.4 m ² /g. .

Referring to FIG. 3A, in the case of furnace carbon black subjected to gas phase oxidation treatment for 10 minutes, it was observed that the internal crystallites were blurred, and it was confirmed that the micropore volume increased by about 2.4 times compared to furnace carbon black as a raw material.

3b and 3c, in the case of furnace carbon black subjected to gas phase oxidation treatment for 30 minutes, 55 minutes and 98 minutes, it can be confirmed that internal pores are developed and the crystallinity of the walls surrounding the pores is increased. .

And, looking at FIG. 3c, in the case of the furnace carbon black subjected to the gas phase oxidation treatment for 115 minutes, the walls surrounding the internal pores became somewhat thin and some slippage occurred. 3D, in the case of furnace carbon black subjected to gas phase oxidation treatment for 148 minutes, the BET specific surface area is increased by about 18 times compared to that of the raw material, and pores are developed and grown (combined) to form primary particles of carbon black. collapse was observed.

In addition, the furnace carbon black subjected to the gas phase oxidation treatment for 148 minutes had a problem in that the yield of the product was too low because the burn-off yield was too high at 83.2%.

In addition, looking at Table 2 and FIG. 3, the BET specific surface area, micropore volume, and total pore volume tended to increase as the gas phase oxidation reaction time increased, but when the gas phase oxidation reaction was performed for too long, the pores were distorted and , There was a phenomenon of coalescence between furnace blacks, and the appropriate gas phase oxidation reaction time to secure appropriate physical properties and yield was 30 minutes to 150 minutes, preferably 40 minutes to 120 minutes, more preferably 45 minutes to 110 minutes was able to confirm that

Preparation Example 1-2: Preparation of microporous hollow furnace carbon black according to reaction temperature

The furnace carbon black (raw material) was subjected to vapor phase oxidation in the same manner as in Preparation Example 1-1, but the oxidation treatment temperature was changed as shown in Table 3 below to prepare microporous hollow furnace carbon black, respectively. Physical properties of the furnace carbon black were measured.

Looking at Table 3, it can be seen that as the reaction temperature increases, the burn-off yield increases, the BET specific surface area, micropore volume, and total pore volume increase, and the average pore size tends to decrease. In the case of 1250 ℃, where the temperature exceeded 1200 ℃, compared to 1150 ℃, the burn-off yield increased rapidly, and the average pore size increased. This is because the micropores decreased and the macropores increased. Because of this, the total pore volume was significantly increased.

And, when the reaction temperature is less than 850 ° C., 800 ° C., there is a problem of having too low physical properties in terms of specific surface area and micropore volume.

Preparation Example 1-3: CO ₂ Preparation of microporous hollow furnace carbon black according to flow rate

In the same manner as in Preparation Example 1-1, the furnace carbon black (raw material) was subjected to vapor phase oxidation, but as a reaction gas, CO ₂ (concentration: 99.950 vol%), an oxidizing gas, was changed as shown in Table 4 below, and a microporous hollow furnace was prepared. Each carbon black was prepared, and the physical properties of the prepared microporous hollow furnace carbon black were measured.

Referring to Table 4, as the CO ₂ flow rate increased, the burn-off yield increased, and the BET specific surface area, micropore volume, and total pore volume tended to increase. However, when the CO ₂ flow rate was 45 ml/min, the yield was too low. When the CO ₂ flow rate was 210 ml/min, the physical properties such as yield, specific surface area, micropore volume, and total pore volume were excellent, but the pores were too small. It was large and formed a lot, so the strength was too weak, so there was a problem that it was easily broken.

<Preparation Example 2: Manufacture of porous hollow furnace carbon black assembly>

Preparation Example 2-1: Preparation of microporous hollow furnace carbon black assembly according to reaction time

Furnace carbon black (trade name: Super-P, manufacturer: IMERYS) was prepared as a raw material. Basic physical properties of the prepared furnace carbon black are shown in Table 5 below.

Next, after preheating the horizontal tubular furnace (oxidation chamber) shown in FIG. 1 to 1000 ° C, the raw material is charged into the reaction tube of the oxidation chamber using a quartz boat, and then fixed at 1000 ° C. A gas phase oxidation reaction was performed. An oxidizing gas containing CO ₂ at a concentration of 99.950 vol% as a reactive material was used, and the flow rate of the oxidizing gas was maintained at 150 ml/min using a ball flow meter. And, the reaction time is shown in Table 6 below.

Next, a plurality of micro hollow furnace carbon blacks are combined from the gas phase oxidation reactant including micro hollow furnace carbon black and combinations thereof by activating and separating the integrated body (aggregate) to obtain a micro porous hollow furnace carbon black assembly. obtained.

In addition, when the reaction time was 0 min, 55 min, 98 min, and 115 min, a transmission electron microscope (TEM, magnification: 800,000 times) measurement photograph of the formed microporous hollow furnace carbon black is shown in FIG. 4a.

In addition, when the reaction time was 98 minutes, a photograph of the microporous hollow furnace carbon black obtained at different magnifications is shown in FIG. 4B.

In addition, SEM measurement photographs of aggregates of microporous hollow furnace carbon black obtained at reaction times of 98 minutes, 115 minutes, and 148 minutes are shown in FIG. 4C.

Referring to FIG. 4a, in the case of furnace carbon black not subjected to gas phase oxidation treatment, no pores were observed inside and no pores were developed inside, so it could be confirmed that the BET specific surface area was very small at 61.4 m ² /g. .

Referring to FIG. 4A, in the case of furnace carbon black subjected to gas phase oxidation treatment for 55 minutes, 98 minutes, and 115 minutes, it was observed that internal crystallites were blurred and micropores were formed, compared to furnace carbon black as a raw material. It was confirmed that the volume increased by 1.5 to 8.1 times.

In addition, referring to FIG. 4B , it can be confirmed that a plurality of microporous hollow furnace carbon blacks are combined and integrated to form a combined aggregate, and internal spaces of the combined carbon black are connected to form a tunnel inside the aggregate.

Referring to FIG. 4C , it can be seen that the length of the assemblies (assemblies and assemblies) tends to increase as the gas phase oxidation treatment reaction time increases.

In addition, the yield (%), BET specific surface area (m ² /g), and mesopore volume (cm ³ /g) of the microporous hollow furnace carbon black assembly prepared and obtained according to each reaction time are shown in the table below. 6.

Looking at Table 6, the BET specific surface area, mesopore volume, and total pore volume tended to increase as the gas phase oxidation reaction time increased. However, when the gas phase oxidation reaction was performed for too long, the furnace carbon black assembly structure collapsed and It was confirmed that there is a problem in which the yield is lowered.

Therefore, it was confirmed that the appropriate gas phase oxidation reaction time for securing the yield was 80 minutes to 150 minutes, preferably 80 minutes to 130 minutes, and more preferably 90 minutes to 120 minutes.

Preparation Example 2-2: Preparation of microporous hollow furnace carbon black assembly according to reaction temperature

The furnace carbon black (raw material) was subjected to vapor phase oxidation in the same manner as in Preparation Example 2-1, but the oxidation treatment temperature was varied as shown in Table 7 below to prepare microporous hollow furnace carbon black assemblies, respectively. The physical properties of the void hollow furnace carbon black assembly were measured.

Looking at Table 7, it can be seen that the yield increases as the reaction temperature increases, and the BET specific surface area and mesopore volume tend to increase. In comparison, there is a problem in that the yield of the microporous hollow furnace carbon black assembly rapidly decreases, which is due to the increase in burn-off carbon black, and the carbon black skin constituting the assembly is too thin, so that the carbon that is broken and separated from the assembly It is judged that this is because the amount of black increases.

In addition, when the reaction temperature is less than 950 ° C., 900 ° C., there is a problem in that the yield of the conjugate is too low and the mesopore volume has low physical properties.

Example 1: Preparation of positive electrode material for metal-air battery

(1) A binder solution in which a binder and a solvent were mixed was prepared. At this time, polyvinylidene fluoride (PVDF) was used as a binder, and N-methyl-2-pyrrolidone (NMP) was used as a solvent.

(2) Furnace carbon black (trade name: Super-P, manufacturer: IMERYS) was prepared as a raw material. Basic physical properties of the prepared furnace carbon black are shown in Table 1 above. Next, after preheating the horizontal tubular furnace (oxidation chamber) shown in FIG. 1 to 1000 ° C, the raw material is charged into the reaction tube of the oxidation chamber using a quartz boat, and then fixed at 1000 ° C. A gas phase oxidation reaction was conducted for 98 minutes to prepare a microporous hollow furnace carbon black. An oxidizing gas containing CO ₂ at a concentration of 99.950 vol% as a reactive material was used, and the flow rate of the oxidizing gas was maintained at 100 ml/min using a ball flowmeter.

(3) A cathode reactant was prepared by mixing the prepared porous hollow furnace carbon black and a binder solution. For the cathode reactant, 90% by weight of the prepared porous hollow furnace carbon black and 10% by weight of the binder are mixed with respect to the total weight% excluding the solvent.

(4) A cathode material for a metal-air battery was prepared by applying the anode reactant to the surface of copper foil and drying it at 100° C. for 6 hours in a vacuum atmosphere.

Example 2: Preparation of positive electrode material for metal-air battery

(1) A binder solution in which a binder and a solvent were mixed was prepared. At this time, polyvinylidene fluoride (PVDF) was used as a binder, and N-methyl-2-pyrrolidone (NMP) was used as a solvent.

(2) Furnace carbon black (trade name: Super-P, manufacturer: IMERYS) was prepared as a raw material. Basic physical properties of the prepared furnace carbon black are shown in Table 1 above. Next, after preheating the horizontal tubular furnace (oxidation chamber) shown in FIG. 1 to 1000 ° C, the raw material is charged into the reaction tube of the oxidation chamber using a quartz boat, and then fixed at 1000 ° C. , a gas phase oxidation reaction was performed for 98 minutes. An oxidizing gas containing CO ₂ at a concentration of 99.950 vol% as a reactive material was used, and the flow rate of the oxidizing gas was maintained at 100 ml/min using a ball flowmeter. Next, a plurality of micro hollow furnace carbon blacks are combined from the gas phase oxidation reactant including micro hollow furnace carbon black and combinations thereof by activating and separating the integrated body (aggregate) to obtain a micro porous hollow furnace carbon black assembly. obtained.

(3) A cathode reactant was prepared by mixing the obtained porous hollow furnace carbon black assembly and a binder solution. For the cathode reactant, 90% by weight of the obtained porous hollow furnace carbon black assembly and 10% by weight of the binder were mixed with respect to the total weight% excluding the solvent.

(4) A cathode material for a metal-air battery was prepared by applying the anode reactant to the surface of copper foil and drying it at 100° C. for 6 hours in a vacuum atmosphere.

Example 3: Preparation of positive electrode material for metal-air battery

(1) A binder solution in which a binder and a solvent were mixed was prepared. At this time, polyvinylidene fluoride (PVDF) was used as a binder, and N-methyl-2-pyrrolidone (NMP) was used as a solvent.

(2) Furnace carbon black (trade name: Super-P, manufacturer: IMERYS) was prepared as a raw material. Basic physical properties of the prepared furnace carbon black are shown in Table 1 above. Next, after preheating the horizontal tubular furnace (oxidation chamber) shown in FIG. 1 to 1000 ° C, the raw material is charged into the reaction tube of the oxidation chamber using a quartz boat, and then fixed at 1000 ° C. , a gas phase oxidation reaction was performed for 55 minutes. An oxidizing gas containing CO ₂ at a concentration of 99.950 vol% as a reactive material was used, and the flow rate of the oxidizing gas was maintained at 100 ml/min using a ball flowmeter. Next, a plurality of micro hollow furnace carbon blacks are combined from the gas phase oxidation reactant including micro hollow furnace carbon black and combinations thereof by activating and separating the integrated body (aggregate) to obtain a micro porous hollow furnace carbon black assembly. obtained.

(3) A cathode reactant was prepared by mixing the obtained porous hollow furnace carbon black assembly with a binder solution. For the cathode reactant, 90% by weight of the obtained porous hollow furnace carbon black assembly and 10% by weight of the binder were mixed with respect to the total weight% excluding the solvent.

(4) A cathode material for a metal-air battery was prepared by applying the anode reactant to the surface of copper foil and drying it at 100° C. for 6 hours in a vacuum atmosphere.

Example 4: Preparation of positive electrode material for metal-air battery

(1) A binder solution in which a binder and a solvent were mixed was prepared. At this time, polyvinylidene fluoride (PVDF) was used as a binder, and N-methyl-2-pyrrolidone (NMP) was used as a solvent.

(2) Furnace carbon black (trade name: Super-P, manufacturer: IMERYS) was prepared as a raw material. Basic physical properties of the prepared furnace carbon black are shown in Table 1 above. Next, after preheating the horizontal tubular furnace (oxidation chamber) shown in FIG. 1 to 1000 ° C, the raw material is charged into the reaction tube of the oxidation chamber using a quartz boat, and then fixed at 1000 ° C. , a gas phase oxidation reaction was performed for 170 minutes. An oxidizing gas containing CO ₂ at a concentration of 99.950 vol% as a reactive material was used, and the flow rate of the oxidizing gas was maintained at 100 ml/min using a ball flowmeter. Next, a plurality of micro hollow furnace carbon blacks are combined from the gas phase oxidation reactant including micro hollow furnace carbon black and combinations thereof by activating and separating the integrated body (aggregate) to obtain a micro porous hollow furnace carbon black assembly. obtained.

(3) A cathode reactant was prepared by mixing the obtained porous hollow furnace carbon black assembly with a binder solution. For the cathode reactant, 90% by weight of the obtained porous hollow furnace carbon black assembly and 10% by weight of the binder were mixed with respect to the total weight% excluding the solvent.

(4) A cathode material for a metal-air battery was prepared by applying the anode reactant to the surface of copper foil and drying it at 100° C. for 6 hours in a vacuum atmosphere.

Manufacturing Example 1: Manufacturing of metal-air battery

A 2032 coin-type metal-air battery composed of a cathode material for a metal-air battery, a cathode material for a metal-air battery, an electrolyte and a separator was manufactured. At this time, as a positive electrode material for a metal air battery, the positive electrode material for a metal air battery prepared in Example 1 was rolled and compressed, and as a negative electrode material for a metal air battery, a lithium metal negative electrode material manufactured in an ar-filled globe box was used. , 1M LiNO ₃ in DMAc and 1M NaOTf in DME were used as the electrolyte, and a Whatman GF/C glass fiber separator was used as the separator.

Manufacturing Example 2: Manufacturing of metal-air battery

A metal-air battery was manufactured in the same manner as in Preparation Example 1. However, unlike Preparation Example 1, the cathode material for a metal-air battery prepared in Example 2 was used as a cathode material for a metal-air battery.

Manufacturing Example 3: Manufacturing of metal-air battery

A metal-air battery was manufactured in the same manner as in Preparation Example 1. However, unlike Preparation Example 1, the positive electrode material for metal-air batteries prepared in Example 3 was used as the positive electrode material for metal-air batteries.

Preparation Example 4: Preparation of metal-air battery

A metal-air battery was manufactured in the same manner as in Preparation Example 1. However, unlike Preparation Example 1, the positive electrode material for a metal-air battery prepared in Example 4 was used as a positive electrode material for a metal-air battery.

Experimental Example 1: Charge and discharge profile of metal-air battery, profile stability, cut-off, CO during charge ₂ Occurrence measurement

Through charge and discharge experiments for each of the metal-air batteries prepared in Preparation Examples 1 to 4, experiments using differential electrochemical mass spectrometry (DEMS), and cycle experiments, charge and discharge profiles, profile stability, cutoff, and charge CO ₂ generation was measured and shown in Table 8 below.

As can be seen from Table 8, in particular, since the metal-air batteries prepared in Examples 1 and 2 did not generate CO ₂ during charging, the cathode materials for metal-air batteries prepared in Examples 1 and 2 were excellent in use as cathode materials. I was able to confirm.

Simple modifications or changes of the present invention can be easily performed by those skilled in the art, and all such modifications or changes can be considered to be included in the scope of the present invention.

Claims (10)

A first step of preparing a cathode active material containing at least one selected from microporous hollow furnace carbon black and microporous hollow furnace carbon black assembly;
A second step of preparing a cathode reactant by mixing the cathode active material and a binder; and
A third step of preparing a cathode material for a metal-air battery by applying the anode reactant on the surface of the metal foil and then drying it; including,
The microporous hollow furnace carbon black assembly
Step 1-1 of preparing furnace carbon black;
1-2 steps of performing a gas phase oxidation reaction of the furnace carbon black using CO ₂ , which is an oxidizing gas; and
1st to 3rd steps of separating a composite in which a plurality of hollow furnace carbon blacks are bonded from gas phase oxidation reactants; Manufactured including,
Each of the plurality of hollow furnace carbon blacks has a hollow structure and has a plurality of micro-sized pores,
In the assembly, a plurality of microporous hollow furnace carbon blacks are combined and integrated,
Internal pores in all or some of the combined plurality of microporous hollow furnace carbon blacks are connected to each other to form internal tunnels in the hollow furnace carbon black assembly,
The method of manufacturing a cathode material for a metal-air battery, characterized in that the mesopore volume of the assembly satisfies Equation 2 below.
[Equation 2]
3.0 ≤ B/A ≤ 5.5
In Equation 2, A is the mesopore volume of the furnace carbon black before the gas phase oxidation reaction is performed, and B is the mesopore volume of the conjugate formed after the gas phase oxidation reaction is performed.
According to claim 1,
The cathode reactant is a method for producing a cathode material for a metal-air battery, characterized in that mixed with 70 to 95 wt% of the cathode active material and 5 to 30 wt% of the binder, based on the total weight%.
delete delete delete metal foil; and
An anode reactant formed on the surface of the metal foil; including,
The cathode reactant includes a cathode active material including a microporous hollow furnace carbon black assembly and a binder,
The microporous hollow furnace carbon black assembly
A plurality of micro-porous hollow carbon blacks are combined and include a single or plural combined body,
Each of the plurality of microporous hollow furnace carbon blacks has a hollow structure and has a plurality of micro-sized pores,
In the composite, internal pores in all or some of the plurality of microporous hollow furnace carbon blacks are connected to each other to form an internal tunnel in the hollow furnace carbon black composite,
A cathode material for a metal-air battery, characterized in that the mesopore volume of the conjugate satisfies Equation 2 below.
[Equation 2]
3.0 ≤ B/A ≤ 5.5
In Equation 2, A is the mesopore volume of the furnace carbon black before the gas phase oxidation reaction is performed, and B is the mesopore volume of the conjugate formed after the gas phase oxidation reaction is performed.
According to claim 6,
The cathode material for a metal-air battery, characterized in that the cathode reactant comprises 70 to 95 wt% of the cathode active material and 5 to 30 wt% of the binder, based on the total weight%.
delete delete The positive electrode material for a metal-air battery of any one of claims 6 and 7; anode materials for metal-air batteries; electrolyte; and a separator; A metal-air battery comprising a.