Metal foil current collector combined with mxene, and negative electrode, positive electrode, and supercapacitor comprising same

Abstract

The present invention relates to a metal foil current collector combined with MXene, and a negative electrode, a positive electrode, and a supercapacitor comprising same and, more specifically, to: a metal foil current collector combined with MXene, the current collector having a metal foil and two-dimensional MXene combined with the metal foil; a super capacitor comprising the current collector; a positive electrode metal foil current collector and a negative electrode metal foil current collector combined with the MXene; and a positive electrode for a secondary battery and a negative electrode for a secondary battery, which comprise a positive electrode active material and a negative electrode active material along with the positive electrode metal foil current collector and the negative electrode metal foil current collector, respectively.

Description

Metal foil current collectors combined with MXene, cathodes, anodes, and supercapacitors including the same

[0001] The present invention relates to a metal foil current collector combined with a maxine, a cathode, an anode, and a supercapacitor including the same.

[0002] Conventional metal materials such as copper and silver have high electrical conductivity and have been used in various ways as electrodes and wiring in electronic devices in the semiconductor, display, and information and communication fields. However, their use is limited due to reasons such as relatively high density, high manufacturing cost, difficulty in applying printing process, oxidation and corrosiveness, and insufficient flexibility.

[0003] MXene is a novel nanomaterial with a two-dimensional structure that has high electrical conductivity and excellent solvent dispersibility (mainly in water and hydrophilic solvents). Therefore, research on the development of MXene and MXene / polymer composite materials is very active in the fields of flexible electrodes for printed electronics, thin-film sensors, high-power batteries and supercapacitors, and electromagnetic shielding.

[0004] MXenes are two-dimensional crystalline transition metal carbides. Twenty different MXene compositions have been synthesized so far, including Ti2C, Ti3C2, Nb2C, V2C, Ta4C3, Mo2TiC2, Mo2Ti2C3, and Cr2TiC2. These MXenes exhibit the best electrical conductivity among the recently developed two-dimensional materials.

[0005] MXene can be synthesized from a ceramic material commonly referred to as MAX. MAX has a layered structure of transition metals [e.g., titanium (Ti), niobium (Nb), vanadium (V), tantalum (Ta), molybdenum (Mo), chromium (Cr)], carbon, and Group 14 elements [e.g., aluminum (Al) or silicon (Si)]. By selectively removing only the Group 14 elements through an etching process, a two-dimensional MXene is obtained.

[0006] In most cases up to now, the etching process has been carried out using a strong acid in an aqueous medium, which causes the surface of MXene to have terminal groups such as -OH, =O, -F, and -Cl, and among these, the -OH functional group in particular gives MXene hydrophilic properties.

[0007] MXene synthesized in this way has excellent water dispersibility properties and can be made into a film or sheet using processes such as filtering or bar coating to exhibit excellent electrical conductivity properties.

[0008] However, the existing aqueous etching process using an aqueous solution cannot avoid the problem that water and dissolved oxygen easily oxidize the surface of MXene during the process, causing the formation of metal oxides such as TiO2, and thus reducing the inherent high electrical conductivity of MXene.

[0009] In addition, due to the hydrophilic nature of the MXene surface, MXene, which can only be dispersed in water, has low interaction and bonding strength with other hydrophobic organic materials (polymers, organic substances), so it has been used very restrictively in forming a uniform composite material. In addition, because a long drying process is required at high temperatures to remove water with a high boiling point and heat of vaporization after the solution process, its application to liquid printing processes such as spray coating, spin coating, inkjet printing, bar coating, gravure coating, and web coating has also been limited.

[0010] Accordingly, the present invention has been devised to solve the above-mentioned conventional problems, and according to an embodiment of the present invention, the purpose is to provide a maxine composite metal foil current collector in a battery or supercapacitor.

[0011] According to an embodiment of the present invention, there is provided a metal foil current collector with MXene bonded thereto, a cathode, an anode, and a supercapacitor including the same, wherein a MXene sheet thin film is formed on a metal foil without using a binder or adhesive on the metal foil, the MXene thin film has a thickness of about 500 nm (an organic MXene thin film has a thickness of about 200 nm), all MXene sheets are parallel to each other and are arranged parallel to the metal foil, and the resistance can be reduced by 50% or more compared to a case where the MXene thin film is not applied.

[0012] And, according to an embodiment of the present invention, the purpose is to provide a metal foil current collector bonded with an organic MXene, which increases the bonding strength with a metal foil current collector by applying an organic MXene surface-modified to be hydrophobic, thereby increasing the stability of a thin film, further reducing resistance, and enabling coating with a thinner thickness, and a cathode, a positive electrode, and a supercapacitor including the same.

[0013] Meanwhile, the technical tasks to be achieved in the present invention are not limited to the technical tasks mentioned above, and other technical tasks not mentioned can be clearly understood by a person having ordinary knowledge in the technical field to which the present invention belongs from the description below.

[0014] The first object of the present invention can be achieved by providing a metal foil current collector, comprising: a metal foil; and a two-dimensional MXene bonded to the metal foil; and a metal foil current collector bonded with the MXene.

[0015] And the above MXene is coated in a thin film form on the surface of the metal foil, and the two-dimensional MXene is M n+1 X n Crystal cells having an empirical formula of at least one layer comprising a two-dimensional array, wherein X is located within an octahedral array composed of M, wherein M is a metal selected from the group consisting of a Group IIIB metal, a Group IVB metal, a Group VB metal, and a Group VIB metal, and wherein X is C, N, or a combination thereof, and n=1,2,3, or 4.

[0016] In addition, the above two-dimensional MXene is M'2M" n X n+1 Crystal cells having an empirical formula of X may include at least one layer forming a two-dimensional array, wherein X is located within an octahedral array formed of M, and M' and M" are different metals selected from the group consisting of a Group IIIB metal, a Group IVB metal, a Group VB metal, and a Group VIB metal, and X is C, N, or a combination thereof, and n=1 or 2.

[0017] And the above two-dimensional MXene can be characterized as an organic MXene whose surface is hydrophobically modified by an organic ligand.

[0018] In addition, the organic MXene is modified with an external surface of a two-dimensional MXene selected from the group consisting of a compound containing a hydroxyl group, an ionic compound, an azide-based surface-modifying compound, a phosphate having a saturated or unsaturated hydrocarbon, and a combination thereof, and the compound containing a hydroxyl group is at least one of a diol-based compound, a boronic acid-based compound, a carboxylic acid-based compound, a sulfonic acid-based compound, and a sulfinic acid-based compound, and the ionic compound is a cation selected from the group consisting of an imidazolium-based compound, a pyridinium-based compound, an ammonium-based compound, a phosphinium-based compound, and a combination thereof; and F - , Cl - , Br - , I - , BF 4- , PF 6- , (CF3SO2)2N - , CF3SO3 - , C2N 3- , CH3SO 3- , CF3BF 3- , C2F5BF 3- , NO 3- , CF3CO 2- , C3H5O 3- and may be characterized by including one anion selected from a combination thereof.

[0019] And the above two-dimensional maxine is an organic maxine, and the organic maxine can be characterized by being obtained by organically etching A of the MAX using an organic etching reagent and an organic solvent in MAX.

[0020] The second object of the present invention can be achieved by a positive electrode metal foil current collector for a secondary battery, which is composed of a metal foil current collector combined with a maxine according to the first object mentioned above.

[0021] And the above metal foil may be characterized as being an aluminum metal foil.

[0022] The third object of the present invention can be achieved by a negative electrode metal foil current collector for a secondary battery, which is composed of a metal foil current collector combined with a maxine according to the first object mentioned above.

[0023] Additionally, the metal foil may be characterized as being a copper metal foil.

[0024] The fourth object of the present invention can be achieved by a supercapacitor including a metal foil current collector combined with a maxine according to the first object mentioned above.

[0025] The fifth object of the present invention can be achieved by a secondary battery positive electrode including a secondary battery positive electrode metal foil current collector according to the second object mentioned above; and a positive electrode active material.

[0026] And the above cathode active material may be characterized by being at least one of NCM type and iron phosphate type.

[0027] The sixth object of the present invention can be achieved by a secondary battery negative electrode comprising a secondary battery negative electrode metal foil current collector according to the third object mentioned above; and a negative electrode active material.

[0028] And the above negative electrode active material may be characterized as being graphite-based, graphene-based, or silicon-based.

[0029] According to a metal foil current collector having a MXene bonded thereto according to an embodiment of the present invention, a MXene sheet thin film is formed on a metal foil without using a binder or adhesive on the metal foil, the MXene thin film has a thickness of about 500 nm (an organic MXene thin film is about 200 nm), and all the MXene sheets are parallel to each other and arranged parallel to the metal foil, and have an effect of reducing resistance by more than 50% compared to a case where the MXene thin film is not applied.

[0030] And according to the metal foil current collector combined with the organic MXene according to an embodiment of the present invention, the negative electrode, positive electrode, and supercapacitor including the same, the organic MXene whose surface is hydrophobically modified is applied to increase the bonding strength with the metal foil current collector, thereby improving the stability of the thin film, further reducing the resistance, and enabling coating with a thinner thickness.

[0031] Meanwhile, the effects that can be obtained from the present invention are not limited to the effects mentioned above, and other effects that are not mentioned can be clearly understood by a person having ordinary skill in the technical field to which the present invention belongs from the description below.

[0032] The following drawings attached to this specification illustrate preferred embodiments of the present invention and, together with the detailed description of the invention, serve to further understand the technical idea of ​​the present invention, and therefore, the present invention should not be interpreted as being limited to matters described in such drawings.

[0033] Figure 1 shows 1) a copper metal foil, 2) a copper metal foil current collector combined with an organic MXene according to an experimental example of the present invention, 3) a negative electrode in which a negative electrode active material, a copper metal foil, and an organic MXene are combined.

[0034] Figure 2 shows 1) aluminum metal foil, 2) organic MXene-bonded aluminum metal foil current collector according to an experimental example of the present invention, 3) a cathode in which a cathode active material, aluminum metal foil, and organic MXene are bonded.

[0035] Figure 3 is a graph showing the electrochemical impedance (EIS, electrochemical Ompedance Spectroscopy) results of 1) copper metal foil, 2) organic MXene-bonded copper metal foil current collector according to an experimental example of the present invention, and 3) a negative electrode in which a negative electrode active material, copper metal foil, and organic MXene are bonded.

[0036] Figure 4 is a graph showing the electrochemical impedance (EIS, electrochemical Ompedance Spectroscopy) results of 1) aluminum metal foil, 2) organic MXene-bonded aluminum metal foil current collector according to an experimental example of the present invention, and 3) a cathode in which a cathode active material, aluminum metal foil, and organic MXene are bonded.

[0037] Figure 5 is a photograph of a copper metal foil and a cathode active material (Si) combined with non-surface-modified Maxine after 3 days of curing.

[0038] Figure 6 is a photograph of a copper metal foil combined with a surface-modified organic MXene and a negative electrode active material (Si) after 3 days of curing.

[0039] Figure 7 is an electron microscope surface photograph of each of a copper metal foil, a copper metal foil combined with organic MXene, and a negative electrode active material (Si) and copper metal foil combined with organic MXene.

[0040] Figure 8 is an electron microscope surface photograph of an aluminum metal foil, an aluminum metal foil combined with organic MXene, and an organic MXene-combined cathode active material (NCM) and an aluminum metal foil, respectively.

[0041] Figure 9 shows cross-sectional electron microscope photographs of 1) a cathode active material bonded with non-surface-modified MXene and aluminum metal foil (upper left), 2) a cathode active material bonded with surface-modified organic MXene and aluminum metal foil (left and right), and 3) a cathode active material bonded with surface-modified organic MXene and copper metal foil (lower left).

[0042] Hereinafter, the configuration of a metal foil current collector combined with a maxine according to an embodiment of the present invention will be described in detail.

[0043] According to an embodiment of the present invention, a metal foil current collector applied to a secondary battery or a supercapacitor has a configuration in which a MXene thin film is combined and coated.

[0044] MXenes are two-dimensional crystalline transition metal carbides. Twenty different MXene compositions have been synthesized so far, including Ti2C, Ti3C2, Nb2C, V2C, Ta4C3, Mo2TiC2, Mo2Ti2C3, and Cr2TiC2. These MXenes exhibit the best electrical conductivity among the recently developed two-dimensional materials.

[0045] MXene can be synthesized from a ceramic material commonly referred to as MAX. MAX has a layered structure of transition metals [e.g., titanium (Ti), niobium (Nb), vanadium (V), tantalum (Ta), molybdenum (Mo), chromium (Cr)], carbon, and Group 14 elements [e.g., aluminum (Al) or silicon (Si)]. By selectively removing only the Group 14 elements through an etching process, a two-dimensional MXene is obtained.

[0046] According to an embodiment of the present invention, the two-dimensional maxine is M, as described in [Background Technology of the Invention]. n+1 X n A two-dimensional array of crystal cells having an empirical formula of at least one layer, wherein each X is positioned within an octahedral array of a plurality of Ms, wherein M is at least one metal selected from the group consisting of a group IIIB metal, a group IVB metal, a group VB metal, and a group VIB metal.

[0047] Each of the above Xs is one selected from C, N and a combination thereof, and n may be 1, 2 or 3.

[0048] According to an embodiment of the present invention, the two-dimensional MXene is M'2M" n X n+1A two-dimensional array of crystal cells having an empirical formula of at least one layer, wherein each X is positioned within an octahedral array of a plurality of M' and M", wherein the M' and M" are different metals selected from the group consisting of a Group IIIB metal, a Group IVB metal, a Group VB metal, and a Group VIB metal, wherein each X is C, N, or a combination thereof, and wherein n may be 1 or 2.

[0049]

[0050] A dispersion of these MXenes in a hydrophilic solvent (water) can be coated on a positive electrode metal foil (e.g., aluminum metal foil) and a negative electrode metal foil (e.g., copper metal foil) using a doctor blade coating method, and then dried to manufacture a MXene-bonded positive electrode current collector and negative electrode current collector.

[0051] In addition, a MXene-coupled positive electrode can be manufactured by coating MXene on a positive electrode in which a positive electrode active material such as NCM or iron phosphate is combined on an aluminum metal foil using a doctor blade coating method and then drying the coating, and a MXene-coupled positive electrode can be manufactured by coating MXene on a negative electrode in which a negative electrode active material such as graphite, graphene, or silicon is combined on a copper metal foil using a doctor blade coating method and then drying the coating.

[0052] According to an embodiment of the present invention, a MXene sheet thin film can be bonded to a metal foil with a thickness of about 500 nm without using a separate binder or adhesive, and when such MXene is applied to a metal foil current collector, resistance can be reduced by 50% or more.

[0053]

[0054] In an embodiment of the present invention, an organic MXene surface-modified to be hydrophobic or manufactured using an organic etching method can be bonded to and coated on a metal foil. By applying the organic MXene, resistance can be further reduced, and compared to an unmodified MXene, the bonding strength with the metal foil can be increased, thereby enhancing the stability of the thin film.

[0055] Various embodiments may be applied to the method of surface modification of Maxine, and these embodiments are merely preferred examples and should not be construed as limiting the scope of the rights.

[0056] These organic MXenes can modify the outer surface of the two-dimensional MXene with one selected from the group consisting of compounds containing hydroxyl groups, ionic compounds, azide-based surface-modifying compounds, phosphates having saturated or unsaturated hydrocarbons, and combinations thereof.

[0057] The compound containing a hydroxyl group may be one selected from the group consisting of a diol compound, a boronic acid compound, a carboxylic acid compound, a sulfonic acid compound, a sulfinic acid compound, a compound represented by the following chemical formula 1, and a combination thereof.

[0058] [Chemical Formula 1]

[0059]

[0060] By selecting a compound containing the hydroxyl group from the above, the solubility of the compound in an organic solvent can be changed, and the binding force to the surface of the two-dimensional MXene can be improved.

[0061] And the ionic compound is a cation selected from the group consisting of imidazolium compounds, pyridinium compounds, ammonium compounds, phosphinium compounds and combinations thereof; and F - , Cl - , Br - , I - , BF 4- , PF 6-, (CF3SO2)2N - , CF3SO3 - , C2N 3- , CH3SO 3- , CF3BF 3- , C2F5BF 3- , NO 3- , CF3CO 2- , C3H5O 3- and may include one anion selected from a combination thereof.

[0062]

[0063] And the azide-based surface modification compound may be an azide-based compound having the following chemical formula 2 or 2a.

[0064] [Chemical Formula 2]

[0065]

[0066] [Chemical Formula 2a]

[0067]

[0068] In the above chemical formula 2, Y can be represented by the above chemical formula 2a, in the above chemical formula 2a, R2 is an azide group, R3 is 1 to 4 or more alkyl groups or hydrogen atoms and halogen groups, A1 can be selected from at least one of an ester group (-COOR), an amide group (-CONHR), a thioester group (-COSR), a hydrocarbon group (-R), and an ether group (-RO-R'-), and the R and R' can each be independently selected from a C1-30 aliphatic hydrocarbon and an aromatic hydrocarbon.

[0069] A2 is independently C 1-25 Alkyl, C 2-25 Alkenyl, C 2-25 alkynyl, C 6-25 It may be a saturated or unsaturated chain or cyclic hydrocarbon selected from aryl.

[0070] R1 in the above chemical formula 2 is an atomic bond, substituted or unsubstituted C1 to C 25Alkyl group, substituted or unsubstituted C4 to C 20 Aryl group, substituted or unsubstituted C5 to C 21 This heteroaryl group and substituted or unsubstituted C1 to C 20 At least one of the alkylamine groups is selected, and n is an integer from 1 to 10.

[0071] The above A2 may be a saturated or unsaturated heterocyclic or chain hydrocarbon each independently containing at least one heteroatom selected from 1 to 25 carbons, nitrogen, oxygen and sulfur, and the saturated or unsaturated heterocyclic or chain hydrocarbon may not contain or contain at least one selected from carbon, nitrogen, oxygen and sulfur in the middle or catalytic portion of each chain.

[0072]

[0073] And the phosphate having a saturated or unsaturated hydrocarbon may be a compound represented by the following chemical formula 3.

[0074] [Chemical Formula 3]

[0075]

[0076] The above A1, A2 or A3 is a hydrogen atom (-H), a C1-25 saturated or unsaturated hydrocarbon, and is selected from at least one of an amide group (-CONHR), a thioester group (-COSR), and an ester group (-RO-R'-).

[0077] The above A1, A2 or A3 are each independently C 1-25 Alkyl, C 2-25 Alkenyl, C 2-25 alkynyl, C 6-25 A saturated or unsaturated ring or chain hydrocarbon selected from aryl, or may be unsubstituted or substituted with a functional group of a hydroxyl group or a carboxyl group, or may not contain or contain 1 to 25 heteroatoms of C, N, O or S.

[0078]

[0079] In addition, as mentioned above, the organic MXene manufactured by modifying the surface of the MXene with various organic ligands can be coated on a metal foil, and the organic MXene manufactured by applying an organic etching method can be coated on a metal foil.

[0080] An organic etching method according to an embodiment of the present invention comprises preparing MAX and then organically etching A of the MAX using an organic etching reagent and an organic solvent (wherein M is a transition metal, A is a group 14 element, and X is carbon or nitrogen).

[0081] The organic etching reagent according to an embodiment of the present invention may be an organic base-hydrogen fluoride addition product.

[0082] And the organic base is an organic base compound, and the organic base compound may be an organic base, an organic base derivative, or an organic base and a polymer bonding compound or mixture that dissolves better in an organic solvent than in water and allows hydrogen fluoride to remain in the organic solvent by stirring or heating.

[0083] Additionally, the organic base-hydrogen fluoride adduct may be at least one of a pyridine-hydrogen fluoride adduct (Olah's Reagent), an N,N-dimethylpropylene urea (DMPU)-hydrogen fluoride adduct (DMPU-HF adduct), and an alc triethylamine (TEA)-hydrogen fluoride adduct (TEA-HF adduct).

[0084] Below, experimental examples of the present invention and experimental result data will be described.

[0085] MXene synthesis

[0086] First, the synthesis of MXene used in the experiment was performed by adding 45 mL of HCl, 15 mL of distilled water, and 4.8 g of LiF to a Teflon round-bottom flask and heating and stirring at 50°C for 30 minutes.

[0087] Then, 3 g of MAX (Ti3AlC2) was added, heated and stirred at 50°C for 24 hours, and the solution was transferred to a conical tube and centrifuged repeatedly until the pH became 7.

[0088] After this, centrifugation was performed at 12,000 rpm for 1 hour, and the maxine portion excluding the precipitated aluminum portion was extracted.

[0089]

[0090] Surface-modified MXene - Synthesis of Butyl gallate (various other ligands are also available)

[0091] Stirring was performed to dissolve 3.5 mg of butyl gallate in 10 mL of ethanol. 35 mL of MXene dispersed in water at a concentration of 1 mg / mL was added to the butyl gallate solution at room temperature, 1 mL was added, and stirring was performed for 20 hours.

[0092] After 20 hours, centrifugation was performed at 12,000 rpm for 30 minutes, and the supernatant was removed to remove butyl gallate and water not bound to MXene. Finally, ethanol was added to adjust the concentration to the required concentration, preparing a surface-modified MXene solution.

[0093]

[0094] Fabrication of metal foil current collectors including maxine

[0095] The metal foil current collector including the unmodified MXene was coated with a solution containing MXene dispersed in water using a doctor blade coating method on a copper or aluminum metal foil. And 100 o C A maxine metal foil collector was prepared by drying in a vacuum oven.

[0096] In addition, the surface-modified MXene solution dispersed in ethanol at 20 mg / mL was coated on copper or aluminum metal foil using a doctor blade coating method. And 100 oC The organic MXene metal foil collector was prepared by drying in a vacuum oven.

[0097] Coating of non-surface-modified MXene and coating of surface-modified organic MXene were performed on the aluminum metal foil, copper metal foil, and the positive electrode in which the aluminum metal foil and the positive electrode active material were combined, and on the negative electrode in which the copper metal foil and the negative electrode active material were combined.

[0098]

[0099] Figure 1 shows photographs of 1) copper metal foil, 2) an organic MXene-bonded copper metal foil current collector according to an experimental example of the present invention, and 3) a cathode in which a negative electrode active material, copper metal foil, and organic MXene are bonded.

[0100] And Figure 2 shows photographs of 1) aluminum metal foil, 2) an organic MXene-bonded aluminum metal foil current collector according to an experimental example of the present invention, and 3) a cathode in which a cathode active material, aluminum metal foil, and organic MXene are bonded.

[0101] Figure 3 illustrates a graph of electrochemical impedance (EIS, electrochemical Ompedance Spectroscopy) results of 1) copper metal foil, 2) organic MXene-bonded copper metal foil current collector according to an experimental example of the present invention, and 3) a negative electrode in which a negative electrode active material, copper metal foil, and organic MXene are bonded.

[0102] And Figure 4 shows a graph of electrochemical impedance (EIS, electrochemical Ompedance Spectroscopy) results of 1) aluminum metal foil, 2) organic MXene-bonded aluminum metal foil current collector according to an experimental example of the present invention, and 3) a cathode in which a cathode active material, aluminum metal foil, and organic MXene are bonded.

[0103] As illustrated in Fig. 3, when the organic MXene is combined with the copper metal foil current collector, which is the negative electrode current collector, the electrical impedance value is reduced by approximately 61%. Furthermore, when the organic MXene is combined with the negative electrode active material (Si) and the copper metal foil current collector, the electrical impedance value is reduced by approximately 68%. Therefore, it can be seen that the resistance can be reduced by more than 60% compared to when the organic MXene thin film is not applied.

[0104] As illustrated in Fig. 4, when the organic MXene is combined with the aluminum metal foil current collector, which is the positive electrode current collector, the electrical impedance value is reduced by approximately 76%. In addition, when the organic MXene is combined with the positive electrode active material (NCM) and the aluminum metal foil current collector, the electrical impedance value is reduced by approximately 51%.

[0105]

[0106] Figure 5 shows a photograph of a copper metal foil combined with a non-surface-modified MXene and a negative electrode active material (Si) after 3 days of curing, and Figure 6 shows a photograph of a copper metal foil combined with a surface-modified organic MXene and a negative electrode active material (Si) after 3 days of curing.

[0107] As illustrated in Fig. 5, the current collector using the unmodified MXene shows signs of peeling off from the metal foil after 3 days. In contrast, the current collector fabricated using the surface-modified organic MXene is found to remain well adhered to the metal foil even after time has elapsed. Therefore, it can be seen that the application of the hydrophobic surface-modified organic MXene increases the bonding strength with the metal foil current collector, thereby enhancing the stability of the thin film, further reducing storage, and enabling the coating to be made with a thinner thickness.

[0108] Figure 7 shows electron microscope surface photographs of a copper metal foil, a copper metal foil combined with organic MXene, and a negative electrode active material (Si) and copper metal foil combined with organic MXene, respectively.

[0109] And Figure 8 shows electron microscope surface photographs of aluminum metal foil, aluminum metal foil combined with organic MXene, and positive electrode active material (NCM) combined with organic MXene and aluminum metal foil, respectively.

[0110] Also, Fig. 9 shows cross-sectional electron microscope photographs of 1) a cathode active material bonded with non-surface-modified MXene and aluminum metal foil (upper left), 2) a cathode active material bonded with surface-modified organic MXene and aluminum metal foil (left and right), and 3) a cathode active material bonded with surface-modified organic MXene and copper metal foil (lower left).

[0111] In Fig. 9, the left side is a collector using Maxine without surface modification, and the collector made using copper foil fell off during image capturing, so no photo could be obtained.

[0112] As shown in Fig. 9, when organic MXene is applied, it can be seen that the bonding strength between the metal foil and the active material is increased, thereby ensuring the stability of the thin film.

[0113] Additionally, the thickness of the unmodified MXene on the left was confirmed to be approximately 500 nm, and the thickness of the surface-modified MXene on the right was confirmed to be approximately 200 nm.

[0114] That is, even though it shows a thinner thickness, the bonding strength with the metal foil is increased, and as shown in the results of Figures 3 and 4, there is no difference in the resistance reduction between the surface-modified MXene and the existing MXene, and it is expected that the surface-modified MXene will show better results.

[0115]

[0116] In addition, the devices and methods described above are not limited to the configurations and methods of the embodiments described above, and the embodiments may be configured by selectively combining all or part of each embodiment so that various modifications can be made.

Claims

1. As a metal foil collector, metal foil; and A metal foil current collector having a two-dimensional MXene bonded to the metal foil; 2. In paragraph 1, The above Maxine is coated in a thin film form on the surface of the metal foil, The above two-dimensional MXene is M n+1 X n Crystal cells having an empirical formula of at least one layer forming a two-dimensional array, wherein X is located within an octahedral array composed of M, A metal foil current collector having a MXene bond, wherein M is a metal selected from the group consisting of a group IIIB metal, a group IVB metal, a group VB metal, and a group VIB metal, X is C, N, or a combination thereof, and n=1,2,3, or 4.

3. In paragraph 2, The above two-dimensional MXene is M'2M" n X n+1 Crystal cells having an empirical formula of at least one layer forming a two-dimensional array, wherein X is located within an octahedral array composed of M, The above M' and M" are different metals selected from the group consisting of Group IIIB metals, Group IVB metals, Group VB metals, and Group VIB metals, A metal foil current collector having a MXene bond, wherein X is C, N or a combination thereof, and n=1 or 2.

4. In paragraph 1, A metal foil current collector having a MXene bonded thereto, characterized in that the above two-dimensional MXene is an organic MXene whose surface is hydrophobically modified by an organic ligand.

5. In paragraph 4, The above organic MXene is modified on the outer surface of the two-dimensional MXene with one selected from the group consisting of a compound containing a hydroxyl group, an ionic compound, an azide-based surface-modifying compound, a phosphate having a saturated or unsaturated hydrocarbon, and a combination thereof. The compound containing the above hydroxyl group is at least one of a diol compound, a boronic acid compound, a carboxylic acid compound, a sulfonic acid compound, and a sulfinic acid compound, The above ionic compound is a cation selected from the group consisting of imidazolium compounds, pyridinium compounds, ammonium compounds, phosphinium compounds, and combinations thereof; and F - , Cl - , Br - , I - , BF 4- , PF 6- , (CF3SO2)2N - , CF3SO3 - , C2N 3- , CH3SO 3- , CF3BF 3- , C2F5BF 3- , NO 3- , CF3CO 2- , C3H5O 3- A metal foil current collector having a MXene bond comprising an anion selected from a combination thereof.

6. In paragraph 1, The above two-dimensional maxine is an organic maxine, The above organic MAX is a metal foil current collector in which MAX is combined by organic etching A of the above MAX using an organic etching reagent and an organic solvent.

7. A positive electrode metal foil current collector for a secondary battery, comprising a metal foil current collector to which a maxine according to any one of claims 1 to 6 is combined.

8. In paragraph 7, The above metal foil is an aluminum metal foil, and is a positive electrode metal foil current collector for a secondary battery.

9. A negative electrode metal foil current collector for a secondary battery, comprising a metal foil current collector combined with a maxine according to any one of claims 1 to 6.

10. In paragraph 9, The above metal foil is a copper metal foil, and is a negative electrode metal foil current collector for a secondary battery.

11. A supercapacitor comprising a metal foil current collector combined with a maxine according to any one of claims 1 to 6.

12. A positive electrode metal foil current collector for a secondary battery according to Article 7; and A cathode for a secondary battery comprising a cathode active material.

13. In paragraph 12, A cathode for a secondary battery, wherein the cathode active material is at least one of NCM type and iron phosphate type.

14. A negative metal foil current collector for a secondary battery according to Article 9; and A negative electrode for a secondary battery, comprising a negative electrode active material.

15. In paragraph 14, The above negative electrode active material is a negative electrode for a secondary battery, which is a graphite-based, graphene-based, or silicon-based material.

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