Negative electrode, lithium metal battery including same, and method for manufacturing same

Abstract

Provided are: a negative electrode; a lithium metal battery including the negative electrode; and a method for manufacturing the negative electrode. The negative electrode includes a modified porous carbon structure, wherein, in X-ray photoelectron spectroscopy (XPS) of the surface of the modified porous carbon structure, the energy position at which the intensity of a peak attributed to lithium (Li) atoms is greatest is 45-65 eV.

Description

Anode, lithium metal battery including same, and method for manufacturing same

[0001] The present invention relates to a cathode, a lithium metal battery including the same, and a method for manufacturing the cathode.

[0002] Lithium secondary batteries currently on the market primarily use carbon-based anode materials, such as graphite. Carbon-based anode materials exhibit no volume change during charge and discharge, contributing to the stability of lithium secondary batteries. Graphite's theoretical electrical capacity is relatively small, at approximately 372 mAh / g.

[0003] Lithium metal can be used as an anode active material. The theoretical electrical capacity of lithium metal is approximately 3,860 mAh / g, which is higher than that of graphite. During charge / discharge, lithium metal can form dendrites on its surface due to side reactions with the electrolyte. These dendrites can grow and cause short circuits between the anode and cathode. Consequently, the lifespan of lithium metal batteries containing lithium metal may be reduced.

[0004] A method for improving the life characteristics of a lithium metal battery containing lithium metal is required.

[0005] One aspect is to provide a new structure of cathode.

[0006] Another aspect is to provide a lithium metal battery comprising a cathode of a novel structure.

[0007] Another aspect is to provide a method for manufacturing a cathode of a new structure.

[0008] According to one embodiment, a negative electrode including a modified porous carbon structure is provided, wherein the energy position at which the intensity of a peak attributable to lithium (Li) atoms in X-ray photoelectron spectroscopy (XPS) of the surface of the modified porous carbon structure is maximum is 45 to 65 eV.

[0009] According to another embodiment, a lithium metal battery is provided, comprising: a positive electrode; a negative electrode according to the above; and an electrolyte disposed between the positive electrode and the negative electrode.

[0010] According to another embodiment, a method for manufacturing a negative electrode is provided, comprising: preparing bare porous carbon and a lithium salt aqueous solution; immersing the bare porous carbon in the lithium salt aqueous solution to prepare lithium salt-treated porous carbon; and heat-treating the lithium salt-treated porous carbon to provide a modified porous carbon structure.

[0011] According to one aspect, it is possible to provide a lithium metal battery with improved Coulombic efficiency by adopting a negative electrode having a new structure.

[0012] Figure 1 is a cross-sectional view of a lithium metal battery according to an exemplary embodiment.

[0013] FIG. 2 is an enlarged cross-sectional view of a portion of a lithium metal battery according to an exemplary embodiment.

[0014] Figure 3 is a cross-sectional view of a lithium metal battery according to another exemplary embodiment.

[0015] Figure 4 is a cross-sectional view of a lithium metal battery according to another exemplary embodiment.

[0016] Figure 5 is a flowchart for explaining a method for manufacturing a cathode according to an exemplary embodiment.

[0017] Figure 6 is a scanning electron microscope image of a cross-section of a cathode manufactured in a comparative example.

[0018] Figure 7 is a scanning electron microscope image of a cross-section of a cathode manufactured in Example 2.

[0019] Figure 8 shows the results of X-ray photoelectron spectroscopy (XPS) analysis of the cathode surface manufactured in Example 1.

[0020] Figure 9 shows the results of analysis using a Fourier transform infrared spectrometer (FTIR) on the cathode surface manufactured in Example 1 and Comparative Example.

[0021] Figure 10 is a graph showing a negative electrode charge curve in a voltage profile for lithium metal batteries manufactured in Example 2 and Comparative Example.

[0022] Figure 11 is a graph showing the Coulombic efficiency for lithium metal batteries manufactured in Example 2 and Comparative Example.

[0023] The present inventive concept described below is capable of various modifications and embodiments. Specific embodiments are illustrated in the drawings and described in detail. However, this is not intended to limit the present inventive concept to specific embodiments, and should be understood to encompass all modifications, equivalents, or alternatives within the technical scope of the present inventive concept.

[0024] The terminology used below is only used to describe specific embodiments and is not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly indicates otherwise. Hereinafter, the terms “comprises” or “has” and the like are intended to indicate the presence of a feature, number, step, operation, component, part, ingredient, material or combination thereof described in the specification, but should be understood to not exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, ingredients, materials or combinations thereof. The term “and / or” used below may be interpreted as “and” or “or” depending on the context.

[0025] In order to clearly express various layers and regions in the drawings, the thickness is shown enlarged or reduced. The same drawing reference numerals are used for similar parts throughout the specification. When a layer, film, region, plate, etc. is said to be “on” or “above” another part throughout the specification, this includes not only cases where it is directly above the other part, but also cases where there is another part in between. Terms such as first, second, etc. may be used throughout the specification to describe various components, but the components should not be limited by the terms. In this specification and the drawings, components having substantially the same functional configuration are referred to by the same reference numerals, and redundant descriptions are omitted.

[0026] In the present disclosure, the “size” of a particle is, for example, the “particle diameter” of the particle. The “particle diameter” of a particle represents the average diameter when the particle is spherical, and represents the average major axis length when the particle is non-spherical. The particle diameter of a particle can be measured using a particle size analyzer (PSA). The “particle diameter” of a particle is, for example, the average particle diameter. The average particle diameter is, for example, the median particle diameter (D50). The median particle diameter (D50) is the size of a particle corresponding to 50% of the cumulative volume, calculated from the side of particles having a small particle size in a size distribution of particles measured by, for example, laser diffraction.

[0027] In this disclosure, “metal” includes both metals and metalloids such as silicon and germanium, in their elemental or ionic states.

[0028] In this disclosure, “alloy” means a mixture of two or more metals.

[0029] In the present disclosure, “positive electrode active material” means a positive electrode material capable of undergoing lithiation and delithiation.

[0030] In the present disclosure, “negative electrode active material” means a negative electrode material capable of undergoing lithiation and delithiation.

[0031] In the present disclosure, “lithiation” and “lithiating” mean a process of adding lithium to a positive electrode active material or a negative electrode active material.

[0032] In the present disclosure, “delithiation” and “delithiate” mean a process of removing lithium from a positive electrode active material or a negative electrode active material.

[0033] In this disclosure, “charging” and “charging” mean a process of providing electrochemical energy to a battery.

[0034] In the present disclosure, “positive electrode” and “cathode” mean an electrode at which electrochemical reduction and lithiation occur during a discharge process.

[0035] In the present disclosure, “cathode” and “anode” mean electrodes where electrochemical oxidation and delithiation occur during the discharge process.

[0036] Hereinafter, a negative electrode, a lithium metal battery including the same, and a method for manufacturing the same according to exemplary embodiments are described in more detail.

[0037] Lithium metal batteries that use lithium metal as the anode active material experience significant volume changes in the anode during the charge / discharge process due to the precipitation and dissolution of a lithium-containing metal layer between the anode current collector and the electrolyte layer. Furthermore, as the lithium metal battery undergoes repeated charge / discharge cycles, the lithium-containing metal layer contains impurities remaining in the electrode, electrolyte decomposition products, and other substances. Consequently, the inclusion of these impurities causes the surface of the lithium-containing metal layer to become rough and hard. Lithium dendrites are then precipitated on the lithium-containing metal layer with this rough surface. These lithium dendrites can continuously grow during the charge / discharge process, potentially causing a short circuit between the positive and negative electrodes. Furthermore, as the lithium metal battery undergoes repeated charge / discharge cycles, the electrolyte is continuously consumed due to side reactions, which can rapidly deteriorate the cycle characteristics of the lithium metal battery.

[0038] To solve this problem, a porous carbon structure capable of supporting lithium metal was introduced into the lithium anode to minimize volume change of the anode and improve the cycle characteristics of the lithium metal battery.

[0039] Meanwhile, during the initial charging of a lithium metal battery, as lithium ions move from the anode to the cathode, components within the electrolyte react with the electrode material to form a solid interface in the form of a film on the surface of the cathode. This is called the Solid Electrolyte Interphase (SEI). The SEI plays a role similar to a separator that prevents short circuits between electrodes, contributing to the stability of the battery. However, the initial lithium ions consumed during the formation of the SEI can reduce the energy density of the lithium metal battery.

[0040] Since the porous carbon structure has a large specific surface area, a relatively large amount of lithium is consumed to form SEI during the initial charge / discharge process, which may reduce the energy density of the lithium metal battery.

[0041] [cathode]

[0042] Referring to FIGS. 1 and 2, an anode (200) according to one embodiment is an anode (200) including a modified porous carbon structure, and the position of energy at which the intensity of a peak attributed to lithium (Li) atoms is maximum in X-ray photoelectron spectroscopy (XPS) analysis of the surface of the modified porous carbon structure is 45 to 65 eV. A lithium metal battery equipped with an anode (200) including such a modified porous carbon structure can improve the initial coulombic efficiency and enhance the energy density of the lithium metal battery.

[0043] The modified porous carbon structure may include empty spaces, i.e., pores, within the carbon structure. Accordingly, lithium metal may be introduced into the outer surface and interior of the modified porous carbon structure. For example, lithium may be precipitated on the surface and / or interior of the modified porous carbon structure. The modified porous carbon structure may introduce a porous carbon structure capable of supporting lithium metal into a lithium anode, thereby minimizing volume changes in the anode (200) and improving the cycle characteristics of a lithium metal battery.

[0044] For example, the modified porous carbon structure may include carbon black (CB), acetylene black (AB), furnace black (FB), ketjen black (KB), graphene, carbon nanotubes (CNT), carbon nanofibers (CNF), hard carbon, soft carbon, reduced graphene oxide (rGO), or a combination thereof. Such a carbon structure can maintain its structure even when lithium metal is introduced to the outer surface and the interior. Such a carbon structure can not only serve as a support for supporting lithium on the outer surface and the interior, but also serve as a current collector.

[0045] According to one embodiment, the negative electrode (200) may omit the current collector. That is, in this case, the modified porous carbon structure (10) may be formed into a certain shape by itself to form the negative electrode (200) without the metal current collector. For example, the porous carbon structure (10) may form an electrodeposition layer (220) and may be formed in a film form on a separator. As another example, the porous carbon structure (10) may form an electrodeposition layer (220) and may be formed in a film form on a solid electrolyte layer.

[0046] Referring to FIG. 2, the modified porous carbon structure may include a lithium-containing functional group (20). The lithium-containing functional group (20) may include, for example, a lithium carboxylate functional group (-CO2Li), a lithium carbonate functional group (-CO3Li), a lithium oxalate functional group (-C2O4Li or (-OCO2Li)2), a lithium acetate functional group (-C2H3O2Li or -CH3COOLi), a lithium hydroxy acetate functional group (-OCH2COOLi), a lithium methoxide functional group (-OCH3Li), a lithium ethoxide functional group (-OC2H5Li), a lithium phenoxide functional group (-OC6H5Li), or a combination thereof. The modified porous carbon structure may improve the lithium affinity (lithiophilicity) of the porous carbon structure, thereby inducing uniform deposition of lithium within the carbon structure. The above-mentioned modified porous carbon structure can prevent the electrolyte from being continuously consumed by side reactions as the charging and discharging of the lithium metal battery is repeated. The above-mentioned modified porous carbon structure can prevent excessive SEI from being formed on the surface of the carbon structure, thereby improving the initial coulombic efficiency of the lithium metal battery and enhancing the energy density of the lithium metal battery. The lithium-containing functional group (20) can be introduced onto the surface of the modified porous carbon structure (10), for example, during the modification process. The lithium-containing functional group (20) can be connected to the modified porous carbon structure (10), for example, through a covalent bond.

[0047] The content of lithium atoms in X-ray photoelectron spectroscopy (XPS) of the surface of the modified porous carbon structure (10) may be 3 to 10 at%. For example, the content of lithium atoms in X-ray photoelectron spectroscopy (XPS) of the surface of the modified porous carbon structure (10) may be 4 to 10 at%, or 5 to 10 at%. If the content of lithium atoms in the surface of the modified porous carbon structure (10) is too small, the initial coulombic efficiency may be reduced due to the formation of an SEI film. If the content of lithium atoms in the surface of the modified porous carbon structure (10) is too large, the stability of the battery may be reduced due to a side reaction.

[0048] Referring to FIG. 8, the energy position at which the intensity of the peak attributed to lithium (Li) atoms in X-ray photoelectron spectroscopy (XPS) of the surface of the modified porous carbon structure (10) is maximum may be 45 to 65 eV. Through this, it can be seen that the modified porous carbon structure (10) includes a lithium-containing functional group (20). For example, the energy position at which the intensity of the peak attributed to lithium (Li) atoms in X-ray photoelectron spectroscopy (XPS) of the surface of the modified porous carbon structure (10) is maximum may be 45 to 60 eV, 50 to 60 eV, 55 to 60 eV, or 55 to 57.5 eV.

[0049] The modified porous carbon structure may further include an oxygen-containing functional group. For example, the oxygen-containing functional group may be, but is not limited to, a hydroxyl group (-OH), a carboxyl group (-COOH), a carbonyl group (-C(=O)-), etc. The oxygen-containing functional group may be introduced onto the surface of the modified porous carbon structure (10), for example, during the modification process. The oxygen-containing functional group may be connected to the modified porous carbon structure (10), for example, through a covalent bond. The oxygen-containing functional group included in the modified porous carbon structure (10) may improve the lithium affinity (lithiophilicity) of the modified porous carbon structure (10), thereby inducing uniform deposition of lithium within the carbon structure.

[0050] The modified porous carbon structure (10) according to one embodiment may include amorphous carbon. Since the modified porous carbon structure (10) includes amorphous carbon, for example, lithium may be deposited on the surface of the modified porous carbon structure (10). The amorphous carbon may have a substantially increased reaction area. Since the modified porous carbon structure (10) including amorphous carbon includes a plurality of nanochannels, the diffusion rate of lithium may be increased. Whether the modified porous carbon structure (10) includes amorphous carbon may be confirmed by, but is not necessarily limited to, low angle XRD.

[0051] The specific surface area of ​​the modified porous carbon structure is, for example, 60 m 2 / g to 1500 m 2 / g, 60 m 2 / g to 1200 m 2 / g, or 80 m 2 / g to 1200 m 2 / g. Since the modified porous carbon structure (10) has a specific surface area in this range, a lithium metal battery having improved discharge capacity and / or high rate characteristics can be provided. The specific surface area of ​​the modified porous carbon structure (10) can be measured, for example, through a nitrogen adsorption experiment or through a transmission electron microscope, but is not necessarily limited thereto.

[0052] The pore volume of the modified porous carbon structure is, for example, 0.6 to 2.0 cm 3 / g, 0.6 to 1.5 cm 3 / g, or 0.6 to 1.0 cm 3 / g. The modified porous carbon structure (10) having a pore volume in this range can provide a lithium metal battery having improved discharge capacity and / or high rate characteristics. The pore volume of the modified porous carbon structure (10) can be measured, for example, through a nitrogen adsorption experiment or through a transmission electron microscope, but is not necessarily limited thereto.

[0053] The cathode (200) according to one embodiment may further include a first carbon-based material that is distinct from the modified porous carbon structure (10). For example, the first carbon-based material may be derived from untreated porous carbon during the process of modifying the porous carbon structure. The first carbon-based material may include, for example, polyacrylonitrile (PAN)-based carbon fibers, pitch-based carbon fibers, cellulose-based carbon fibers, or a combination thereof.

[0054] The negative electrode (200) according to one embodiment may additionally include a crystalline or amorphous carbon-based material that is distinct from the modified porous carbon structure (10) and the first carbon-based material. The crystalline or amorphous carbon-based material may be, for example, graphite, carbon black (CB), acetylene black (AB), furnace black (FB), ketjen black (KB), graphene, carbon nanotubes, carbon nanofibers, etc., but is not necessarily limited thereto, and any material classified as a carbon-based material in the relevant technical field may be used. The negative electrode (200) according to another embodiment may not additionally include the above-described crystalline or amorphous carbon-based material that is distinct from the modified porous carbon structure (10).

[0055] The negative electrode (200) according to one embodiment may further include a lithium compound. For example, the lithium compound may be derived from a lithium salt aqueous solution during the process of modifying the porous carbon structure. The lithium compound may include lithium citrate (Li3C6H5O7), lithium hexafluorophosphate (LiPF6), lithium bis(oxalato)borate (LiBOB), lithium trifluoromethanesulfonate (LiCF3SO3), lithium perchlorate (LiClO4), lithium nitrate (LiNO3), lithium oxalate (Li2C2O4), lithium acetate (LiC2H3O2), lithium carbonate (Li2CO3), lithium hydroxide (LiOH), lithium methanesulfonate (LiCH3SO3), lithium oxychloride (LiClO), lithium phosphonate (LiPO3), lithium malate (Li2C4H2O4), lithium tartrate (Li2C4H4O6), lithium ascorbate (LiC6H7O6) or combinations thereof.

[0056] The negative electrode (200) according to one embodiment may further include lithium metal or a lithium alloy. For example, the lithium metal or lithium alloy may be generated by lithium ion deposition during the charging process of a lithium metal battery. For example, the lithium metal or lithium alloy may be supported on the modified porous carbon structure (10) described above. For example, the lithium alloy may include a Li-Al alloy, a Li-Sn alloy, a Li-In alloy, a Li-Ag alloy, a Li-Au alloy, a Li-Zn alloy, a Li-Ge alloy, a Li-Si alloy, or a combination thereof.

[0057] Referring to FIG. 3, a negative electrode (200) according to another embodiment further includes a negative electrode current collector (210); and an electrodeposition layer (220) on the negative electrode current collector (210), wherein the electrodeposition layer (220) may include the modified porous carbon structure (10) described above. Since the description of the modified porous carbon structure (10) can be applied as is, a detailed description thereof will be omitted below.

[0058] The negative electrode current collector (210) can provide a reference surface on which the electrodeposition layer (220) is arranged. The negative electrode current collector (210) can include, for example, a material that does not react with lithium, i.e., does not form an alloy or compound with lithium. The material constituting the negative electrode current collector (210) can include, for example, at least one metal selected from the group consisting of copper (Cu), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), and nickel (Ni). The thickness of the negative electrode current collector (210) can be 1 to 20 μm, for example, 5 to 15 μm, for example, 7 to 10 μm.

[0059] The negative electrode current collector (210) may be composed of one of the above-described metals, or may include an alloy or coating material of two or more metals. The negative electrode current collector (210) is, for example, in the form of a plate or foil. In another embodiment, the negative electrode current collector (210) may be omitted.

[0060] The electrodeposition layer (220) can be configured to support lithium or a lithium alloy by including the modified porous carbon structure (10) described above. That is, the electrodeposition layer (220) can act as a lithium reservoir. The lithium alloy can include, for example, a Li-Al alloy, a Li-Sn alloy, a Li-In alloy, a Li-Ag alloy, a Li-Au alloy, a Li-Zn alloy, a Li-Ge alloy, a Li-Si alloy, or a combination thereof.

[0061] Referring to FIG. 4, the negative electrode (200) according to another embodiment may further include a lithium metal layer (230) between the negative electrode current collector (210) and the electrodeposition layer (220). The lithium metal layer (230) is a metal layer including lithium or a lithium alloy, and thus may function as, for example, a lithium reservoir. The lithium alloy may include, for example, a Li-Al alloy, a Li-Sn alloy, a Li-In alloy, a Li-Ag alloy, a Li-Au alloy, a Li-Zn alloy, a Li-Ge alloy, a Li-Si alloy, or a combination thereof. The lithium metal layer (230) may be formed of one of these alloys or lithium, or may be formed of several types of alloys. The lithium metal layer (230) may be, for example, a plated layer. The lithium metal layer (230) may be deposited between the electrodeposition layer (220) and the negative electrode current collector (210), for example, during the charging process of a lithium metal battery. Alternatively, the lithium metal layer (230) may be provided between the electrodeposition layer (220) and the negative electrode current collector (210), for example, before assembling the lithium metal battery. The lithium or lithium alloy included in the lithium metal layer (230) may be the same as or different from the lithium or lithium alloy supported on the modified porous carbon structure (10) described above.

[0062] [Lithium metal battery]

[0063] Referring to FIG. 1, a lithium metal battery according to one embodiment may include a positive electrode (100); a negative electrode (200) according to the above; and an electrolyte layer (300) disposed between the positive electrode (100) and the negative electrode (200). The lithium metal battery (1000) may provide improved coulombic efficiency by including the negative electrode (200) described above. Since the description of the negative electrode (200) is applicable as described above, a detailed description thereof will be omitted below.

[0064] The positive electrode (100) may include a positive electrode current collector (110) and a positive electrode active material layer (120) disposed on one surface of the positive electrode current collector (110). The positive electrode active material layer (120) may include a positive electrode active material, a conductive material, and a binder.

[0065] The positive electrode current collector (110) can provide a reference surface on which the positive electrode active material layer (120) is arranged. The positive electrode current collector (110) can include a plate or foil including, for example, indium (In), copper (Cu), magnesium (Mg), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), aluminum (Al), germanium (Ge), lithium (Li), or an alloy thereof.

[0066] Meanwhile, unlike that illustrated in FIG. 1, in one embodiment, the positive electrode current collector (110) may be omitted. Although not illustrated, a carbon layer having a thickness of 0.1 μm to 4 μm may be additionally disposed between the positive electrode current collector (110) and the positive electrode active material layer (120) to increase the bonding strength between the positive electrode current collector (110) and the positive electrode active material layer (120).

[0067] The cathode active material is a material that can reversibly absorb and desorb lithium ions. The cathode active material may include, but is not necessarily limited to, lithium transition metal oxides such as lithium cobalt oxide (LCO), lithium nickel oxide, lithium nickel cobalt oxide, lithium nickel cobalt aluminum oxide (NCA), lithium nickel cobalt manganese oxide (NCM), lithium manganate, and lithium iron phosphate, nickel sulfide, copper sulfide, lithium sulfide, iron oxide, or vanadium oxide. The cathode active materials may be used alone or as a mixture of two or more.

[0068] Lithium transition metal oxides include, for example, Li a A 1-b B b D2(0.90≤a≤1, 0≤b≤0.5), Li a E 1-b B b O 2-c D c (0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05), LiE 2-b B b O 4-c D c (0≤b≤0.5, 0≤c≤0.05), Li a Ni 1-b-c Co b B c D α (0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05, 0<α<2), Li a Ni 1-b-c Co b B c O 2-α F α (0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05, 0<α<2), Li a Ni 1-b-c Mn b B c D α (0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05, 0<α≤2), Li a Ni 1-b-c Mn b B c O 2-α F α (0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05, 0<α<2), Li a Ni b E c G d O2(0.90≤a≤1, 0≤b≤0.9, 0≤c≤0.5, 0.001≤d≤0.1), Li a Ni b Co c Mn d GeO2(0.90≤a≤1, 0≤b≤0.9, 0≤c≤0.5, 0≤d≤0.5, 0.001≤e≤0.1), Li a NiG bO2(0.9≤a≤1, 0.001≤b≤0.1), Li a CoG b O2(0.90≤a≤1, 0.001≤b≤0.1), Li a MnG b O2(0.90≤a≤1, 0.001≤b≤0.1), Li a Mn2GbO4(0.90≤a≤1, 0.001≤b≤0.1), QO2, QS2, LiQS2, V2O5, LiV2O5, LiIO2, LiNiVO4, Li 3-f J2(PO4)3(0≤f≤2), Li 3-f A compound represented by any one of Fe2(PO4)3(0≤f≤2), LiFePO4. In these compounds, the capital letter “A” is Ni, Co, Mn, or a combination thereof, the capital letter “B” is Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, a rare earth element, or a combination thereof, the capital letter “D” is O, F, S, P, or a combination thereof, the capital letter “E” is Co, Mn, or a combination thereof, the capital letter “F” is F, S, P, or a combination thereof, the capital letter “G” is Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, or a combination thereof, the capital letter “Q” is Ti, Mo, Mn, or a combination thereof, the capital letter “I” is Cr, V, Fe, Sc, Y, or a combination thereof, and the capital letter “J” is V, Cr, Mn, Co, Ni, Cu, or a combination thereof.

[0069] The cathode active material may include, for example, a lithium salt of a transition metal oxide having a layered rock salt type structure among the lithium transition metal oxides described above. The "layered rock salt type structure" is, for example, a cubic rock salt type structure. <111> It is a structure in which oxygen atomic layers and metal atomic layers are alternately and regularly arranged in a direction, and thereby each atomic layer forms a two-dimensional plane. The "cubic rock salt structure" refers to the sodium chloride type (NaCl type) structure, which is a type of crystal structure, and specifically refers to a structure in which the face-centered cubic lattice (fcc) formed by each cation and anion is arranged with a displacement of half of the ridge of the unit lattice. Lithium transition metal oxides having this layered rock salt structure include, for example, LiNi x Co y Al z O2(NCA) or LiNi x Co y Mn z O2(NCM) (0 <x<1,0<y<1, 0<z<1, x+y+z=1) 등의 삼원계 리튬전이금속산화물일 수 있다. 양극 활물질이 층상암염형 구조를 갖는 삼원계 리튬전이금속산화물을 포함하는 경우, 리튬 금속 전지(1000)의 에너지 밀도가 커지고 열안정성이 향상될 수 있다.

[0070] The above-described compound included in the positive electrode active material may be covered by a coating layer (not shown). The positive electrode active material may also be a mixture of the above-described compound and a compound to which a coating layer is added. Meanwhile, the coating layer added to the surface of the positive electrode active material may include, for example, an oxide, a hydroxide, an oxyhydroxide, an oxycarbonate, or a hydroxycarbonate of the coating elements below. The compound forming the coating layer is amorphous or crystalline. The coating elements included in the coating layer may include Mg, Al, Co, K, Na, Ca, Si, Ti, V, Sn, Ge, Ga, B, As, Zr, or mixtures thereof. The coating layer may include, for example, Li2O-ZrO2 (LZO). The method for forming the coating layer is selected within a range that does not adversely affect the physical properties of the positive electrode active material. The method for forming the coating layer includes, for example, spray coating, dipping, etc.

[0071] When the positive electrode active material includes nickel (Ni) as a ternary lithium transition metal oxide such as NCA or NCM, for example, the capacity density of the lithium metal battery (1000) can be increased, thereby reducing metal dissolution of the positive electrode active material in a charged state. As a result, the cycle characteristics of the lithium metal battery (1000) in a charged state are improved. Meanwhile, the “cycle characteristics” are characteristics indicating the degree to which the lithium metal battery (1000) is deteriorated due to charge / discharge of the lithium metal battery (1000). A lithium metal battery (1000) having high cycle characteristics may have a small degree of deterioration of the lithium metal battery (1000) due to charge / discharge, and a lithium metal battery (1000) having low cycle characteristics may have a large degree of deterioration of the lithium metal battery (1000) due to charge / discharge.

[0072] The shape of the positive electrode active material may include particle shapes such as a sphere or an ellipsoid, for example. The particle size and content of the positive electrode active material are not particularly limited.

[0073] The positive electrode active material layer (120) may include a conductive material. The conductive material may be conductive without causing a chemical change in the lithium metal battery (1000), thereby increasing the conductivity of the positive electrode active material. The conductive material may include a carbon-based material. For example, the conductive material may include one or more selected from graphite, carbon black, acetylene black, carbon nanofibers, and carbon nanotubes.

[0074] The positive electrode active material layer (120) may further include a binder. The binder may include a material for binding the positive electrode active material and conductive material included in the positive electrode active material layer (120) and improving bonding strength with the positive electrode current collector (110). The binder may include, for example, polyvinylidene fluoride, styrene butadiene rubber (SBR), polytetrafluoroethylene, polyvinylidene fluoride, vinylidene fluoride / hexafluoropropylene copolymer, polyacrylonitrile, and polymethyl methacrylate.

[0075] The positive electrode active material layer (120) may further include additives such as fillers, coating agents, dispersants, and ion conductive aids in addition to the positive electrode active material, conductive agent, and binder described above.

[0076] A lithium metal battery according to an embodiment may further include a separator between the positive electrode and the negative electrode (200) (not shown).

[0077] As the separator, a multilayer film of two or more layers of polyethylene, polypropylene, polyvinylidene fluoride, or these may be used, and of course, a mixed multilayer film such as a polyethylene / polypropylene two-layer separator, a polyethylene / polypropylene / polyethylene three-layer separator, or a polypropylene / polyethylene / polypropylene three-layer separator may be used.

[0078] The separator may include a porous substrate and a coating layer comprising an organic material, an inorganic material, or a combination thereof, positioned on one or both sides of the porous substrate.

[0079] The above porous substrate may be a polymer film formed of any one polymer selected from polyolefins such as polyethylene and polypropylene, polyesters such as polyethylene terephthalate and polybutylene terephthalate, polyacetal, polyamide, polyimide, polycarbonate, polyether ketone, polyarylether ketone, polyetherimide, polyamideimide, polybenzimidazole, polyethersulfone, polyphenylene oxide, cyclic olefin copolymer, polyphenylene sulfide, polyethylene naphthalate, glass fiber, Teflon, and polytetrafluoroethylene, or a copolymer or mixture of two or more thereof.

[0080] The organic material may include a polyvinylidene fluoride polymer or a (meth)acrylic polymer.

[0081] The above inorganic materials are Al2O3, SiO2, TiO2, SnO2, CeO2, MgO, NiO, CaO, GaO, ZnO, ZrO2, Y2O3, It may include inorganic particles selected from, but not limited to, SrTiO3, BaTiO3, Mg(OH)2, boehmite, and combinations thereof.

[0082] The organic and inorganic substances may be mixed and present in one coating layer, or a coating layer including an organic substance and a coating layer including an inorganic substance may be present in a laminated form.

[0083] The electrolyte layer (300) may include an electrolyte, and the electrolyte may include, for example, a liquid electrolyte, a solid electrolyte, or a combination thereof.

[0084] The liquid electrolyte may include, for example, a non-aqueous organic solvent and a lithium salt. The non-aqueous organic solvent may serve as a medium through which ions involved in the electrochemical reaction of the battery can move. The non-aqueous organic solvent may be a carbonate-based, ester-based, ether-based, ketone-based, or alcohol-based solvent, an aprotic solvent, or a combination thereof.

[0085] Examples of carbonate solvents that can be used include dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), methylpropyl carbonate (MPC), ethylpropyl carbonate (EPC), methylethyl carbonate (MEC), ethylene carbonate (EC), propylene carbonate (PC), and butylene carbonate (BC).

[0086] Ester solvents that can be used include methyl acetate, ethyl acetate, n-propyl acetate, dimethyl acetate, methyl propionate, ethyl propionate, decanolide, mevalonolactone, valerolactone, and caprolactone.

[0087] Examples of ether solvents that can be used include dibutyl ether, tetraglyme, diglyme, dimethoxyethane (DME), 2-methyltetrahydrofuran, 2,5-dimethyltetrahydrofuran, tetrahydrofuran, and bis(2,2,2-trifluoroethyl) ether (BTFE). In addition, cyclohexanone can be used as a ketone solvent. Examples of alcohol solvents that can be used include ethyl alcohol and isopropyl alcohol, and examples of aprotic solvents that can be used include nitriles such as R-CN (where R is a linear, branched, or cyclic hydrocarbon group having 2 to 20 carbon atoms and may include a double bond, an aromatic ring, or an ether group); amides such as dimethylformamide; dioxolanes such as 1,3-dioxolane and 1,4-dioxolane; and sulfolanes.

[0088] Non-aqueous organic solvents can be used alone or in combination of two or more.

[0089] Lithium salts are substances that dissolve in organic solvents and act as a source of lithium ions in the battery, enabling the basic operation of secondary batteries and promoting the movement of lithium ions between the positive and negative electrodes. Representative examples of lithium salts include LiPF6, LiBF4, LiSbF6, LiAsF6, LiClO4, LiAlO2, LiAlCl4, LiPO2F2, LiCl, LiI, LiN(SO3C2F5)2, Li(FSO2)2N (lithium bis(fluorosulfonyl)imide (LiFSI), LiC4F9SO3, LiN(C x F 2x+1 SO2)(C y F 2y+1 SO2) (wherein x and y are integers from 1 to 20), lithium trifluoromethanesulfonate, lithium tetrafluoroethanesulfonate, lithium difluorobis(oxalato)phosphate (LiDFOB), lithium bis(oxalato)borate (LiBOB). The concentration of the lithium salt is, for example, from 0.1 M to 5.0 M.

[0090] The solid electrolyte is, for example, an oxide-based solid electrolyte, a sulfide-based solid electrolyte, or a combination thereof.

[0091] Solid electrolytes are, for example, oxide-based solid electrolytes. Oxide-based solid electrolytes are Li 1+x+y Al x Ti 2-x Si y P 3-y O 12 (0 <x<2, 0≤y<3), BaTiO3, Pb(Zr,Ti)O3(PZT), Pb 1-x La x Zr 1-y Ti y O3(PLZT)(O≤x<1, O≤y<1), PB(Mg3Nb 2 / 3)O3-PbTiO3(PMN-PT), HfO2, SrTiO3, SnO2, CeO2, Na2O, MgO, NiO, CaO, BaO, ZnO, ZrO2, Y2O3, Al2O3, TiO2, SiO2, Li3PO4, Li x Ti y (PO4)3(0 <x<2, 0<y<3), Li x Al y Ti z (PO4)3(0 <x<2, 0<y<1, 0<z<3), Li 1+x+y (Al, Ga) x (Ti, Ge) 2-x Si y P 3-y O 12 (0≤x≤1 0≤y≤1), Li x La y TiO3(0 <x<2, 0<y<3), Li2O, LiOH, Li2CO3, LiAlO2, Li2O-Al2O3-SiO2-P2O5-TiO2-GeO2, Li 3+x La3M2O 12 (M = Te, Nb, or Zr, x is an integer from 1 to 10) is one or more selected from. The solid electrolyte is manufactured by a sintering method, etc. For example, the oxide-based solid electrolyte is Li7La3Zr2O 12 (LLZO) and Li 3+x La3Zr 2-a M a O 12 A garnet-type solid electrolyte selected from (M doped LLZO, M=Ga, W, Nb, Ta, or Al, x is an integer from 1 to 10).

[0092] The sulfide-based solid electrolyte may include, for example, lithium sulfide, silicon sulfide, phosphorus sulfide, boron sulfide, or a combination thereof. The sulfide-based solid electrolyte particles may include Li2S, P2S5, SiS2, GeS2, B2S3, or a combination thereof. The sulfide-based solid electrolyte particles may be Li2S or P2S5. Sulfide-based solid electrolyte particles are known to have high lithium ion conductivity compared to other inorganic compounds. For example, the sulfide-based solid electrolyte includes Li2S and P2S5. When the sulfide solid electrolyte material constituting the sulfide-based solid electrolyte includes Li2S-P2S5, the mixing molar ratio of Li2S to P2S5 may be, for example, in a range of about 50:50 to about 90:10. In addition, Li3PO4, halogen, halogen compound, Li 2+2x Zn 1-x GeO4("LISICON", 0≤x<1), Li 3+y PO 4-x N x ("LIPON", 0 <x<4, 0<y<3), Li 3.25 Ge 0.25 P 0.75An inorganic solid electrolyte prepared by adding S4 ("ThioLISICON"), Li2O-Al2O3-TiO2-P2O5 ("LATP"), etc. to an inorganic solid electrolyte of Li2S-P2S5, SiS2, GeS2, B2S3, or a combination thereof can be used as a sulfide solid electrolyte. Non-limiting examples of sulfide solid electrolyte materials include Li2S-P2S5; Li2S-P2S5-LiX (X=halogen element); Li2S-P2S5-Li2O; Li2S-P2S5-Li2O-LiI; Li2S-SiS2; Li2S-SiS2-LiI; Li2S-SiS2-LiBr; Li2S-SiS2-LiCl; Li2S-SiS2-B2S3-LiI; Li2S-SiS2-P2S5-LiI; Li2S-B2S3; Li2S -P2S5-ZmSn (0 <m<10, 0<n<10, Z=Ge, Zn 또는 Ga); Li2S-GeS2; Li2S-SiS2-Li3PO4; 및 Li2S-SiS2-Li p MO q (0 <p<10, 0<q<10, M=P, Si, Ge, B, Al, Ga 또는 In)을 포함한다. 이와 관련하여, 황화물계 고체전해질 재료는 황화물계 고체전해질 물질의 원료 시작 물질(예를 들면, Li2S, P2S5, 등)을 용융 담금질법(melt quenching method), 기계적 밀링법 등에 의해 처리함으로써 제조될 수 있다. 또한, 소성(calcinations) 공정이 상기 처리 후에 수행될 수 있다. 황화물계 고체전해질은 비정질이거나, 결정질이거나, 이들이 혼합된 상태일 수 있다.

[0093] [Method for manufacturing cathode]

[0094] Fig. 5 is a flowchart illustrating a method for manufacturing a cathode according to an embodiment. Referring to Fig. 5, the method for manufacturing a cathode according to an embodiment will be described in more detail.

[0095] Prepare bare porous carbon and lithium salt aqueous solution.

[0096] A lithium salt aqueous solution can be prepared by adding a lithium salt to a solvent and mixing them. For example, the lithium salt can include lithium citrate (Li3C6H5O7), lithium hexafluorophosphate (LiPF6), lithium bis(oxalato)borate (LiBOB), lithium trifluoromethanesulfonate (LiCF3SO3), lithium perchlorate (LiClO4), lithium nitrate (LiNO3), lithium oxalate (Li2C2O4), lithium acetate (LiC2H3O2), lithium carbonate (Li2CO3), lithium hydroxide (LiOH), lithium methanesulfonate (LiCH3SO3), lithium oxychloride (LiClO), lithium phosphonate (LiPO3), lithium malate (Li2C4H2O4), lithium tartrate (Li2C4H4O6), lithium ascorbate (LiC6H7O6), or a combination thereof. For example, the solvent can be water, ethanol, or the like.

[0097] The lithium salt aqueous solution may contain 1 to 10 parts by weight of the lithium salt based on 100 parts by weight of the lithium salt aqueous solution. For example, the lithium salt aqueous solution may contain 2 to 7 parts by weight, or 3 to 5 parts by weight, of the lithium salt based on 100 parts by weight of the lithium salt aqueous solution.

[0098] The untreated porous carbon may include polyacrylonitrile (PAN)-based carbon fibers, pitch-based carbon fibers, cellulose-based carbon fibers, or a combination thereof.

[0099] Untreated porous carbon is immersed in a lithium salt aqueous solution (S100). The immersed untreated porous carbon is taken out to prepare lithium salt-treated porous carbon. For example, the untreated porous carbon can be prepared by immersing it in the lithium salt aqueous solution, leaving it for more than 10 hours, and then taking it out to prepare lithium salt-treated porous carbon. Alternatively, the untreated porous carbon can be prepared by immersing it in the lithium salt aqueous solution, leaving it for more than 20 hours, and then taking it out to prepare lithium salt-treated porous carbon. The untreated porous carbon can be prepared by immersing it in the lithium salt aqueous solution, leaving it for less than 100 hours, and then taking it out to prepare lithium salt-treated porous carbon.

[0100] In one embodiment, preparing the lithium salt-treated porous carbon may include drying in an oven (S200). For example, drying may be performed at a temperature of 50° C. to 100° C.

[0101] A modified porous carbon structure (10) is provided by heat-treating lithium salt-treated porous carbon (S300). During the heat-treatment process, the porous carbon may be carbonized to form a chemical bond between lithium and the porous carbon. In one embodiment, the heat-treatment may be performed in an inert gas atmosphere after the lithium salt-treated porous carbon is introduced into a reactor. The inert gas may include, but is not necessarily limited to, helium (He), argon (Ar), neon (Ne), krypton (Kr), xenon (Xe), radon (Rn), nitrogen (N2), carbon dioxide (CO2), or a combination thereof.

[0102] In one embodiment, the heat treatment may be performed at a temperature of 500°C to 1,500°C. If the heat treatment temperature is excessively low, the lithium and / or oxygen content on the surface of the modified porous carbon structure (10) may become excessively high or the electrical conductivity may become low. If the heat treatment temperature is excessively high, the physical properties of the modified porous carbon structure (10) may change. The heat treatment temperature may be performed at a temperature of, for example, 900°C to 1,000°C.

[0103] According to another embodiment, a method for manufacturing a negative electrode may further include washing the modified porous carbon structure (10) with washing water (S400). The washing water may include, but is not necessarily limited to, distilled water, ethanol, or a combination thereof. In one embodiment, the method may include drying the modified porous carbon structure (10) in an oven (S400). For example, the drying may be performed at a temperature of 50°C to 100°C. This modified porous carbon structure (10) may not only serve as a support that supports lithium on the outer surface and interior, but may also serve as a current collector.

[0104] According to another embodiment, a method for manufacturing a negative electrode may further include laminating a modified porous carbon structure (10) on a negative electrode current collector. For example, a laminate of a negative electrode current collector / electrodeposition layer is prepared by placing the modified porous carbon structure (10) on the negative electrode current collector and applying pressure. The pressing may be performed by, for example, roll pressing, flat pressing, warm isotactic pressing (WIP), cold isotactic pressing (CIP), etc., but is not necessarily limited to these methods and any pressing method used in the art may be used. The pressure applied during pressing may be, for example, 50 MPa to 500 MPa. The time for applying the pressure may be, for example, 0.1 min to 30 min. The pressing may be performed at, for example, a temperature of room temperature to 90°C or lower, or a temperature of 20 to 90°C. Alternatively, pressurization can be performed at a high temperature of 100°C or higher. The pressurization process can be omitted.

[0105] The following examples and comparative examples further illustrate the present invention. However, these examples are intended to illustrate the present invention and do not limit the scope of the present invention.

[0106] Example 1: Modified porous carbon structure (lithium salt aqueous solution: 4 wt % LiNO3)

[0107] (Manufacture of modified porous carbon structures)

[0108] Cellulose fabric was cut into 1 cm × 1 cm pieces and placed in a 4 wt% aqueous solution of lithium nitrate (LiNO3) and left for 24 hours. The cellulose fabric was taken out and dried in an oven at 70°C until the moisture evaporated completely. The dried cellulose fabric was placed in a reactor, and while supplying nitrogen (N2) gas at a rate of 50 mL / min, the temperature was increased to 950°C over 4 hours, and heat-treated at 950°C for an additional 4 hours, for a total of 8 hours, to manufacture a modified porous carbon structure. The manufactured modified porous carbon structure was washed five times with distilled water and ethanol and then dried in an oven at 70°C until the moisture evaporated completely.

[0109] (Manufacturing of coin cells)

[0110] A coin cell was manufactured by using a lithium foil with a thickness of 20 μm as a counter electrode, placing a polypropylene separator between the counter electrode and the modified porous carbon structure electrode, and then injecting electrolyte (1 M LiFSI in BTFE:DME = 87.5 vol%:12.5 vol%).

[0111] Example 2: Modified porous carbon structure (lithium salt aqueous solution: 4 wt % Li3C6H5O7)

[0112] Coin cells were manufactured in the same manner as in Example 1, except that the cellulose fabric was cut into 1 cm × 1 cm pieces, placed in a 4 wt% aqueous solution of lithium citrate (Li3C6H5O7), and left for 24 hours.

[0113] Comparative example: Untreated porous carbon structure (lithium salt solution treatment omitted)

[0114] Cellulose fabric was cut into 1 cm × 1 cm pieces and placed in a reactor. The temperature was raised to 950°C for 4 hours while supplying nitrogen (N2) gas at a rate of 50 mL / min. Heat treatment was further performed at 950°C for 4 hours, for a total of 8 hours, to produce an untreated porous carbon structure. The produced untreated porous carbon structure was washed five times with distilled water and ethanol and then dried in an oven at 70°C until the moisture was completely evaporated.

[0115] (Manufacturing of coin cells)

[0116] A coin cell was manufactured by using a lithium foil with a thickness of 20 μm as a counter electrode, placing a polypropylene separator between the counter electrode and the modified porous carbon structure electrode, and then injecting electrolyte (1 M LiFSI in BTFE:DME = 87.5 vol%:12.5 vol%).

[0117] Evaluation Example 1: Surface Analysis of Porous Carbon Structure

[0118] The SEM image of the untreated porous carbon structure manufactured in the comparative example is shown in Fig. 6. The SEM image of the modified porous carbon structure manufactured in Example 2 is shown in Fig. 7. Referring to Fig. 6, it can be seen that the surface is smooth, whereas referring to Fig. 7, it can be seen that the surface of the carbon framework is rough. Referring to Fig. 7, it can be seen that the modified porous carbon structure according to Example 2 has chemical bonds formed on the surface by a chemical reaction.

[0119] Evaluation Example 2: Surface composition analysis of modified porous carbon structure (XPS)

[0120] XPS analysis was performed on the surface of the porous carbon structure manufactured in Example 1, and the results are shown in Fig. 8. Referring to Fig. 8, in the case of Example 1, it can be confirmed that the energy position at which the peak intensity due to lithium (Li) atoms reaches its maximum is in the range of 55 eV to 57.5 eV. This confirms that lithium, oxygen, and carbon remaining on the surface of the modified porous carbon structure are in a chemically bonded state. In addition, it was confirmed from the intensity of the peak that the lithium content on the surface of the modified porous carbon structure was approximately 7 at%.

[0121] Evaluation Example 3: Analysis of surface composition of porous carbon structure (FTIR)

[0122] The FTIR analysis results for the surfaces of the porous carbon structures manufactured in Example 1 and Comparative Example are shown in Fig. 9. Referring to Fig. 9, unlike the Comparative Example, peaks corresponding to the stretching vibrations of Li2CO3, (RCO2Li)2, and RCO2Li can be confirmed. Through this, it can be confirmed that, unlike the Comparative Example, the surface of the modified porous carbon structure manufactured in Example 1 has residual lithium, oxygen, and carbon in various forms of chemical bonding.

[0123] Evaluation Example 4: Electrochemical Evaluation (SEI Formation and Coulombic Efficiency Evaluation)

[0124] Figure 10 is a graph showing the negative electrode charge curve in the voltage profile for lithium metal batteries manufactured in Example 2 and the Comparative Example. In the case of Example 2, it can be confirmed that the potential plateau is less distinct in the first cycle compared to the Comparative Example. This indicates that, in the case of Example 2, electrolyte decomposition due to SEI formation occurs less than in the Comparative Example.

[0125] Figure 11 is a graph showing the Coulombic Efficiency for the lithium metal batteries manufactured in Example 2 and Comparative Examples. The half cells manufactured in Example 2 and Comparative Examples were tested at 2 mAh / cm 2 Current density of 4 mAh / cm 2 The coulombic efficiency (%) according to the cycle number was measured while repeating charge and discharge at a capacity of 1 V, a cut-off voltage of 1 V, and 60°C. The coulombic efficiency for the initial charge and discharge of Example 2 was 65%, but the coulombic efficiency for the initial charge and discharge of the comparative example was 54%, which was lower than that of Example 2. Through this, it can be seen that the consumption of lithium ions due to SEI formation was reduced in Example 2 compared to the comparative example. In addition, it was confirmed that the charge and discharge efficiency up to 50 cycles was superior in Example 2 compared to the comparative example. Through this, it was confirmed that the life characteristics of the lithium metal battery including the modified porous carbon structure were improved.

[0126] While exemplary embodiments have been described in detail with reference to the attached drawings, the present invention is not limited to these examples. It is self-evident that those skilled in the art to which the present invention pertains can devise various modifications or variations within the scope of the technical concepts described in the patent claims, and these also naturally fall within the technical scope of the present invention.

Claims

1. A cathode comprising a modified porous carbon structure, A cathode, wherein the energy position at which the intensity of the peak attributed to lithium (Li) atoms in X-ray photoelectron spectroscopy (XPS) analysis of the surface of the above-mentioned modified porous carbon structure is maximum is 45 to 65 eV.

2. In paragraph 1, A cathode having a lithium (Li) atom content of 3 to 10 at% in X-ray photoelectron spectroscopy (XPS) analysis of the surface of the above-mentioned modified porous carbon structure.

3. In paragraph 1, The above modified porous carbon structure is a cathode comprising carbon black (CB), acetylene black (AB), furnace black (FB), ketjen black (KB), graphene, carbon nanotube (CNT), carbon nanofiber (CNF), hard carbon, soft carbon, reduced graphene oxide, or a combination thereof.

4. In paragraph 1, The specific surface area of ​​the above modified porous carbon structure is 60 m 2 / g to 1500 m 2 / g, negative.

5. In paragraph 1, The above modified porous carbon structure includes pores, The pore volume of the above modified porous carbon structure is 0.6 cm 3 / g to 2.0 cm 3 / g, negative.

6. In paragraph 1, The above modified porous carbon structure comprises a lithium-containing functional group, The above lithium-containing functional group comprises a lithium carboxylate functional group (-CO2Li), a lithium carbonate functional group (-CO3Li), a lithium oxalate functional group (-C2O4Li or (-OCO2Li)2), a lithium acetate functional group (-C2H3O2Li or -CH3COOLi), a lithium hydroxy acetate functional group (-OCH2COOLi), a lithium methoxide functional group (-OCH3Li), a lithium ethoxide functional group (-OC2H5Li), a lithium phenoxide functional group (-OC6H5Li), or a combination thereof.

7. In paragraph 1, The above negative electrode further comprises a lithium compound, The negative electrode comprises the lithium compound selected from the group consisting of lithium citrate (Li3C6H5O7), lithium hexafluorophosphate (LiPF6), lithium bis(oxalato)borate (LiBOB), lithium trifluoromethanesulfonate (LiCF3SO3), lithium perchlorate (LiClO4), lithium nitrate (LiNO3), lithium oxalate (Li2C2O4), lithium acetate (LiC2H3O2), lithium carbonate (Li2CO3), lithium hydroxide (LiOH), lithium methanesulfonate (LiCH3SO3), lithium oxychloride (LiClO), lithium phosphonate (LiPO3), lithium malate (Li2C4H2O4), lithium tartrate (Li2C4H4O6), lithium ascorbate (LiC6H7O6) or a combination thereof.

8. In paragraph 1, The above negative electrode further comprises a negative current collector; and an electrodeposition layer on the negative current collector, The above electrodeposition layer comprises the modified porous carbon structure, the negative electrode.

9. Bipolar; The cathode according to paragraph 1; and A lithium metal battery comprising an electrolyte disposed between the positive electrode and the negative electrode.

10. In paragraph 9, The above cathode is, A negative electrode current collector; and further comprising an electrodeposition layer on the negative electrode current collector, A lithium metal battery, wherein the electrodeposition layer comprises the modified porous carbon structure.

11. In paragraph 10, The above cathode is, A lithium metal battery further comprising a lithium metal layer between the negative electrode current collector and the electrodeposition layer.

12. In paragraph 11, The above lithium metal layer may include lithium metal or a lithium alloy, A lithium metal battery, wherein the lithium alloy comprises a Li-Al alloy, a Li-Sn alloy, a Li-In alloy, a Li-Ag alloy, a Li-Au alloy, a Li-Zn alloy, a Li-Ge alloy, a Li-Si alloy or a combination thereof.

13. Preparing bare porous carbon and lithium salt aqueous solution; Preparing lithium salt-treated porous carbon by immersing the bare porous carbon in the lithium salt aqueous solution; and A method for manufacturing a negative electrode, comprising heat-treating the lithium salt-treated porous carbon to provide a modified porous carbon structure.

14. In paragraph 13, A method for manufacturing a cathode, wherein the above untreated porous carbon comprises polyacrylonitrile (PAN)-based carbon fiber, pitch-based carbon fiber, cellulose-based carbon fiber, or a combination thereof.

15. In paragraph 13, The above lithium salt aqueous solution contains a lithium salt, A method for manufacturing a negative electrode, wherein the lithium salt comprises lithium citrate (Li3C6H5O7), lithium hexafluorophosphate (LiPF6), lithium bis(oxalato)borate (LiBOB), lithium trifluoromethanesulfonate (LiCF3SO3), lithium perchlorate (LiClO4), lithium nitrate (LiNO3), lithium oxalate (Li2C2O4), lithium acetate (LiC2H3O2), lithium carbonate (Li2CO3), lithium hydroxide (LiOH), lithium methanesulfonate (LiCH3SO3), lithium oxychloride (LiClO), lithium phosphonate (LiPO3), lithium malate (Li2C4H2O4), lithium tartrate (Li2C4H4O6), lithium ascorbate (LiC6H7O6) or a combination thereof.

16. In paragraph 15, A method for manufacturing a negative electrode, wherein the lithium salt aqueous solution contains 1 to 10 parts by weight of the lithium salt based on 100 parts by weight of the lithium salt aqueous solution.

17. In paragraph 13, A method for manufacturing a negative electrode, wherein the above lithium salt-treated porous carbon is heat-treated at 500 to 1500°C.

18. In paragraph 13, A method for manufacturing a negative electrode, wherein preparing the lithium salt-treated porous carbon further includes drying it in an oven.

19. In paragraph 13, A method for manufacturing a cathode, further comprising washing the above-mentioned modified porous carbon structure with washing water.

20. In paragraph 13, A method for manufacturing a negative electrode, further comprising laminating the modified porous carbon structure on a negative electrode current collector.

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