Negative electrode material and secondary battery including same

Abstract

One embodiment of the present invention relates to a negative electrode material and a secondary battery including same, the negative electrode material comprising: a first layer; a second layer disposed on one surface of the first layer; and a third layer disposed on a surface of the second layer facing away from the first layer, wherein the first layer includes lithium metal, the second layer includes carbon, and the third layer includes a lithiophilic material, and wherein a carbon coating layer and a coating layer including a lithiophilic material are disposed on the surface of the negative electrode material, thereby reducing interfacial resistance of lithium metal and improving lifespan characteristics.

Description

Cathode material and secondary battery including the same

[0001] The present invention relates to a negative electrode material and a secondary battery containing the same.

[0002] While carbon has generally been primarily used as the anode material in secondary batteries, lithium metal has recently been receiving significant attention as a next-generation anode material. Compared to graphite anodes, lithium metal anodes have a much higher capacity, are very lightweight, and can generate higher energy with a lower redox voltage. However, lithium metal anodes exhibit high interfacial resistance due to arbitrary films on the surface, and uneven lithium ion deposition can lead to localized accumulation of lithium ions and the formation of dendrites. This can result in internal short circuits and safety issues.

[0003] Embodiments of the present invention allow for coating the surface of lithium metal to reduce the interfacial resistance of the lithium metal and improve lifespan characteristics.

[0004] An embodiment of the present invention for achieving the purpose described above discloses a cathode material comprising a first layer, a second layer disposed on one surface of the first layer, and a third layer disposed on a surface of the second layer facing in a direction opposite to the direction facing the first layer, wherein the first layer comprises lithium metal, the second layer comprises carbon, and the third layer comprises a lithium-affinity material.

[0005] Another embodiment of the present invention for achieving the purpose described above discloses a cathode material comprising a first layer, a second layer disposed on one side of the first layer, a third layer disposed on the other side of the second layer opposite to the side on which the first layer is disposed, and a fourth layer disposed on the other side of the third layer opposite to the side on which the second layer is disposed, wherein the first layer comprises lithium metal, the second layer comprises a lithium-affinity material, the third layer comprises carbon, and the fourth layer comprises a lithium-affinity material.

[0006] Another embodiment of the present invention for achieving the purpose described above discloses a secondary battery comprising a negative electrode material according to any one of claims 1 to 5.

[0007] In the cathode material according to an embodiment of the present invention, a carbon coating layer and a coating layer including a lithium-affinity material are disposed on the surface, thereby reducing the interfacial resistance of lithium metal and improving lifespan characteristics.

[0008] FIG. 1 is a cross-sectional view schematically illustrating an example of a lithium metal negative electrode material according to one embodiment of the present invention.

[0009] FIG. 2 is a cross-sectional view schematically illustrating an example of a lithium metal negative electrode material according to another embodiment of the present invention.

[0010] An embodiment of the present invention for achieving the purpose described above discloses a cathode material comprising a first layer, a second layer disposed on one surface of the first layer, and a third layer disposed on a surface of the second layer facing in a direction opposite to the direction facing the first layer, wherein the first layer comprises lithium metal, the second layer comprises carbon, and the third layer comprises a lithium-affinity material.

[0011] In this embodiment, the lithium-affinity material may include a metal or a metal oxide.

[0012] In this embodiment, the content of the second layer may be 0.001 wt% to 10 wt% relative to the weight of the first layer.

[0013] In this embodiment, the content of the third layer may be 0.001 wt% to 20 wt% relative to the weight of the first layer.

[0014] Another embodiment of the present invention for achieving the purpose described above discloses a cathode material comprising a first layer, a second layer disposed on one side of the first layer, a third layer disposed on the other side of the second layer opposite to the side on which the first layer is disposed, and a fourth layer disposed on the other side of the third layer opposite to the side on which the second layer is disposed, wherein the first layer comprises lithium metal, the second layer comprises a lithium-affinity material, the third layer comprises carbon, and the fourth layer comprises a lithium-affinity material.

[0015] Another embodiment of the present invention discloses a secondary battery comprising a negative electrode material according to any one of claims 1 to 5.

[0016] The present invention is capable of various modifications and may have various embodiments; specific embodiments are illustrated in the drawings and described in detail in the detailed description. The effects and features of the present invention, and the methods for achieving them, will become clear by referring to the embodiments described below in detail together with the drawings. However, the present invention is not limited to the embodiments disclosed below but can be implemented in various forms.

[0017] In the following embodiments, terms such as first, second, etc. are used not in a limiting sense, but for the purpose of distinguishing one component from another component.

[0018] In the following examples, singular expressions include plural expressions unless the context clearly indicates otherwise.

[0019] In the following embodiments, terms such as "include" or "have" mean that the features or components described in the specification are present, and do not preclude the possibility that one or more other features or components may be added.

[0020] In the following embodiments, when a part such as a film, region, or component is described as being on or above another part, it includes not only cases where it is directly on top of another part, but also cases where another film, region, or component is interposed in between.

[0021] In the drawings, the size of components may be exaggerated or reduced for convenience of explanation. For example, the size and thickness of each component shown in the drawings are depicted arbitrarily for convenience of explanation, so the present invention is not necessarily limited to what is illustrated.

[0022] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings, and when describing with reference to the drawings, identical or corresponding components will be given the same reference numerals.

[0023] FIG. 1 is a cross-sectional view schematically illustrating an example of a lithium metal negative electrode material according to one embodiment of the present invention.

[0024] Referring to FIG. 1, a cathode material (10) according to one embodiment of the present invention may include a first layer (11), a second layer (12) disposed on the first layer (11), and a third layer (13) disposed on the second layer (12).

[0025] The first layer (11) may include lithium metal, and the lithium metal may include, for example, a thin film.

[0026] The second layer (12) may be disposed on one side of the first layer (11), and, for example, may be a coating layer that coats one side of the first layer (11). As a specific example, the second layer (12) may include carbon, and the carbon may include materials with excellent electrical conductivity, and as a specific example, may include one or more selected from CNT (SWCNT, MWCNT), CNF, graphene, crystalline or amorphous carbon.

[0027] Meanwhile, the coating content of the second layer (12) coated on one side of the first layer (11) containing lithium metal can be 0.001 wt% to 10 wt% relative to the lithium weight of the first layer (11).

[0028] Meanwhile, if the coating content of the second layer (12) is less than 0.001 wt% relative to the lithium weight of the first layer (11), there is a problem in that the lithium metal of the first layer (11) comes into direct contact with the electrolyte and does not suppress the formation of the SEI film, and if the coating content of the second layer (12) is more than 10 wt% relative to the lithium weight of the first layer (11), there may be a problem in that the movement path of lithium ions increases and the electrochemical properties of the negative electrode material (10) decrease.

[0029] The third layer (13) may be disposed on the second layer (12) on the other side opposite to the side on which the first layer (11) of the second layer (12) is disposed, and, for example, may be a coating layer that coats the other side of the second layer (12). As a specific example, the third layer (13) may include a lithium-affinity material, wherein the lithium-affinity material may include a metal or a metal oxide. As an example, the metal may include one or more selected from Al, Zn, Ag, Si, In, Mg, Sn, Ga, Bi, B, Au, Pt, Ba, Bs, Ca, Cd, Ir, Pa, Ro, Se, and St, and the metal oxide may include MgO2, Co3O, ZnO, TiO, SnO2, SiO2, Al2O3, MgO, Li 1.3 Al 0.3 Ti 1.7 (PO4)3, Li 1.5 Al 0.5 Ge 1.5 (PO4)3 and Li7La3Zr3O 12 It may include one or more of the selected items.

[0030] Meanwhile, the coating content of the third layer (13) coated on one side of the second layer (12) can be 0.001 wt% to 20 wt% relative to the lithium weight of the first layer (11).

[0031] Meanwhile, if the coating content of the third layer (13) is less than 0.001 wt% relative to the lithium weight of the first layer (11), the lithium electrodeposition energy and interfacial resistance increase, making it difficult to suppress dendrite formation, and if the coating content of the third layer (13) is more than 20 wt% relative to the lithium weight of the first layer (11), the lithium ion movement path increases, and the electrochemical properties of the negative electrode material (10) may decrease.

[0032] Meanwhile, although the cathode material (10) according to one embodiment of the present invention has been described in a case where a second layer (12) and a third layer (13) are coated sequentially on a first layer (11), it is not limited thereto, and the number of coating layers can be increased or the order changed by considering the characteristics of each of the carbon coating layer and the lithium affinity coating layer.

[0033] In an optional embodiment, the arrangement of the second layer (12) and the third layer (13) may be interchanged, for example, the third layer (13) may be coated first on one side of the first layer (11), and the second layer (12) may be coated on the third layer (13).

[0034] In an optional embodiment, a material composed of lithium oxide, lithium nitride, such as Li2O, LiN, Li2CO3, etc., may be located between the first layer (11) and the second layer (12) or between the first layer (11) and the third layer (13).

[0035] Meanwhile, a method for forming a coating layer on the first layer (11) involves sequentially coating a material for forming the second layer (12) and the third layer (13) on the first layer (11), and then compressing it all at once, so that the second layer (12) and the third layer (13) can be coated on the first layer (11), and as a result, a cathode material (10) can be manufactured.

[0036] Meanwhile, if a coating layer is formed with a metal or metal oxide, such as the third layer (13), it can become a lithium alloy through a reaction with lithium during the charging and discharging process of the secondary battery described later.

[0037] Meanwhile, the negative electrode material (10) can lower the lithium electrodeposition energy by means of the third layer (13), which is a lithium-affinity material surface coating layer during lithium ion electrodeposition, thereby reducing the interfacial resistance and making the lithium current uniform so that dendrite formation can be suppressed.

[0038] In addition, the second layer (12), which is a carbon coating layer disposed between the first layer (11) containing lithium metal and the third layer (13) containing a lithium-affinity material, prevents the negative electrode material (10) from coming into direct contact with the electrolyte, thereby suppressing the formation of a Solid Electrolyte Interphase (SEI) film and improving the uniformity of the lithium current, which can improve charge / discharge efficiency and lifespan characteristics.

[0039] As a result, the negative electrode material (10) according to one embodiment of the present invention has a double layer comprising a carbon coating layer and a lithium-affinity material coating layer disposed on the surface of the lithium metal, thereby reducing the interfacial resistance of the lithium metal and improving the lifespan characteristics.

[0040] FIG. 2 is a cross-sectional view schematically illustrating an example of a lithium metal negative electrode material according to another embodiment of the present invention.

[0041] Referring to FIG. 2, a cathode material (20) according to another embodiment of the present invention may include a first layer (21), a second layer (22) disposed on the first layer (21), a third layer (23) disposed on the second layer (22), and a fourth layer (24) disposed on the third layer (23).

[0042] The first layer (21) may include lithium metal, and the lithium metal may include, for example, a thin film.

[0043] The second layer (22) may be disposed on one surface of the first layer (21), and, for example, may be a coating layer that coats one surface of the first layer (21). As a specific example, the second layer (22) may include a lithium-affinity material, wherein the lithium-affinity material may include a metal or a metal oxide. As an example, the metal may include one or more selected from Al, Zn, Ag, Si, In, Mg, Sn, Ga, Bi, B, Au, Pt, Ba, Bs, Ca, Cd, Ir, Pa, Ro, Se, and St, and the metal oxide may include MgO2, Co3O, ZnO, TiO, SnO2, SiO2, Al2O3, MgO, Li 1.3 Al 0.3 Ti 1.7 (PO4)3, Li 1.5 Al 0.5 Ge 1.5 (PO4)3 and Li7La3Zr3O 12 It may include one or more of the selected items.

[0044] Meanwhile, the coating content of the second layer (22) coated on one side of the first layer (21) containing lithium metal can be 0.001 wt% to 20 wt% relative to the lithium weight of the first layer (21).

[0045] Meanwhile, if the coating content of the second layer (22) is less than 0.001 wt% relative to the lithium weight of the first layer (21), the lithium electrodeposition energy increases, which may cause a problem of increased interfacial resistance, and if the coating content of the second layer (22) is more than 20 wt% relative to the lithium weight of the first layer (21), the lithium ion movement path increases, which may reduce the electrochemical properties of the negative electrode material (20).

[0046] The third layer (23) may be disposed on the second layer (22) on the other side opposite to the side on which the first layer (21) of the second layer (22) is disposed, and, for example, may be a coating layer that coats one side of the second layer (22). As a specific example, the third layer (23) may include carbon, and the carbon may include materials with excellent electrical conductivity, and as a specific example, may include one or more selected from CNT (SWCNT, MWCNT), CNF, Graphene, crystalline and amorphous carbon.

[0047] Meanwhile, the coating content of the third layer (23) coated on the other side of the second layer (22) can be 0.001 wt% to 10 wt% relative to the lithium weight of the first layer (21).

[0048] Meanwhile, if the coating content of the third layer (23) is less than 0.001 wt% relative to the lithium weight of the first layer (21), there is a problem in that the lithium metal of the first layer (21) comes into direct contact with the electrolyte and does not suppress the formation of the SEI film, and if the coating content of the third layer (23) is more than 10 wt% relative to the lithium weight of the first layer (21), there may be a problem in that the movement path of lithium ions increases and the electrochemical properties of the negative electrode material (20) decrease.

[0049] The fourth layer (24) may be disposed on the third layer (23) on the other side opposite to the side on which the second layer (22) of the third layer (23) is disposed, and, for example, may be a coating layer that coats the other side of the third layer (23). As a specific example, the fourth layer (24) may include a lithium-affinity material, wherein the lithium-affinity material may include a metal or a metal oxide. As an example, the metal may include one or more selected from Al, Zn, Ag, Si, In, Mg, Sn, Ga, Bi, B, Au, Pt, Ba, Bs, Ca, Cd, Ir, Pa, Ro, Se, and St, and the metal oxide may include MgO2, Co3O, ZnO, TiO, SnO2, SiO2, Al2O3, MgO, Li 1.3 Al 0.3 Ti 1.7 (PO4)3, Li 1.5 Al 0.5 Ge 1.5 (PO4)3 and Li7La3Zr3O 12 It may include one or more of the selected items.

[0050] Meanwhile, the coating content of the fourth layer (24) coated on the other side of the third layer (23) can be 0.001 wt% to 20 wt% relative to the lithium weight of the first layer (21).

[0051] Meanwhile, if the coating content of the fourth layer (24) is less than 0.001 wt% relative to the lithium weight of the first layer (21), the lithium electrodeposition energy and interfacial resistance increase, making it difficult to suppress dendrite formation, and if the coating content of the fourth layer (24) is more than 20 wt% relative to the lithium weight of the first layer (21), the lithium ion movement path increases, and the electrochemical properties of the negative electrode material (20) may decrease.

[0052] Meanwhile, the cathode material (20) according to another embodiment of the present invention has been described as being limited to the case where a second layer (22), a third layer (23), and a fourth layer (24) are coated in order on a first layer (21), but it is not limited thereto, and the number of coating layers can be increased or the order changed by considering the characteristics of each of the carbon coating layer and the lithium affinity coating layer.

[0053] As an optional embodiment, a material composed of lithium oxide, lithium nitride, such as Li2O, LiN, Li2CO3, etc., may be located between the first layer (21) and the second layer (22) or between the first layer (21) and the third layer (23).

[0054] Meanwhile, a method for forming a coating layer on the first layer (21) involves sequentially coating a material for forming the second layer (22), the third layer (23), and the fourth layer (24) on the first layer (21), and then compressing it all at once, so that the second layer (22), the third layer (23), and the fourth layer (24) can be coated on the first layer (21), and as a result, a cathode material (20) can be manufactured.

[0055] Meanwhile, if a coating layer is formed with a metal or metal oxide, such as the second layer (22) or the fourth layer (24), it may become a lithium alloy through a reaction with lithium during the charging and discharging process of the secondary battery described later.

[0056] Meanwhile, the negative electrode material (20) can lower the lithium electrodeposition energy by means of the second layer (22) or the fourth layer (24), which is a surface coating layer of a lithium-affinity material during lithium ion electrodeposition, thereby reducing the interfacial resistance and making the lithium current uniform so that dendrite formation can be suppressed.

[0057] In addition, the third layer (23), which is a carbon coating layer placed between the second layer (22) and the fourth layer (24) containing a lithium-affinity material, prevents the negative electrode material (20) from coming into direct contact with the electrolyte, thereby suppressing the formation of a Solid Electrolyte Interphase (SEI) film and improving the uniformity of the lithium current, which can improve charge / discharge efficiency and lifespan characteristics.

[0058] As a result, the negative electrode material (20) according to another embodiment of the present invention has a triple layer comprising a lithium-affinity material coating layer, a carbon coating layer, and a lithium-affinity material coating layer disposed on the surface of the lithium metal, thereby reducing the interfacial resistance of the lithium metal and improving the lifespan characteristics.

[0059] A secondary battery using a negative electrode material (10, 20) according to an embodiment of the present invention as a negative electrode may include a negative electrode, a positive electrode, a separator, and an electrolyte.

[0060] Secondary batteries may include lithium secondary batteries, and may be classified into lithium-ion batteries, lithium-ion polymer batteries, and lithium-polymer batteries depending on the type of separator and electrolyte used, and may be classified into cylindrical, prismatic, coin, pouch types, etc. depending on the shape, and may be divided into bulk type and thin film type depending on the size, and one aspect of the present invention may include all of these.

[0061] A secondary battery can be manufactured by placing a separator between a negative electrode and a positive electrode to produce an electrode assembly, housing it in a case, and then injecting a lithium salt-containing electrolyte. The negative electrode may include a negative electrode material (10, 20) according to an embodiment of the present invention.

[0062] The cathode may include, for example, 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 manganese oxide, and lithium iron phosphate, but is not necessarily limited to these, and any material used as a cathode active material in the relevant technical field may be used.

[0063] The separation membrane may include, for example, sheets or nonwoven fabrics made of olefin-based polymers such as chemically resistant and hydrophobic polypropylene, glass fibers, or polyethylene, but is not necessarily limited to these, and any material that can be used as a separation membrane in the relevant technical field may be used.

[0064] The electrolyte may include non-aqueous electrolytes and lithium salts. Non-aqueous electrolytes may include non-aqueous electrolyte solutions, solid electrolytes, inorganic solid electrolytes, etc. For example, the non-aqueous electrolyte is N-methyl-2-pyrrolidinone, propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, gamma-butyrolactone, 1,2-dimethoxyethane, tetrahydrofuran (THF), 2-methyl tetrahydrofuran, dimethyl sulfoxide, 1,3-dioxolan, formamide, dimethylformamide, dioxolan, acetonitrile, nitromethane, methyl formate, methyl acetate, phosphate triester, trimethoxymethane, dioxolan derivative, sulfolane, methyl sulfolane, 1,3-dimethyl-2-imidazolidinone, propylene carbonate derivative, tetrahydrofuran derivative, ether, propionic acid It may include aprotic organic solvents such as methyl, ethyl propionate, etc.

[0065] Organic solid electrolytes may include, for example, polyethylene derivatives, polyethylene oxide derivatives, polypropylene oxide derivatives, phosphate ester polymers, polyagitation lysine, polyester sulfides, polyvinyl alcohol, polyvinylidene fluoride, polymers containing ionic dissociators, etc.

[0066] For example, as inorganic solid electrolytes, nitrides, halides, sulfates of Li such as Li3N, LiI, Li5NI2, Li3N-LiI-LiOH, LiSiO4, LiSiO4-LiI-LiOH, Li2SiS3, Li4SiO4, Li4SiO4-LiI-LiOH, Li3PO4-Li2S-SiS2, Li10GeP2S12, and Li7P3S11 can be used.

[0067] The lithium salt is a substance that is easily soluble in the above-mentioned non-aqueous electrolyte and may include, for example, LiCl, LiBr, LiI, LiClO4, LiBF4, LiB10Cl10, LiPF6, LiCF3SO3, LiCF3CO2, LiAsF6, LiSbF6, LiAlCl4, CH3SO3Li, CF3SO3Li, (CF3SO2)2NLi, lithium chloroborane, lithium lower aliphatic carboxylate, lithium tetraphenylborate, etc.

[0068] As a result, a secondary battery comprising the negative electrode material according to an embodiment of the present invention as a negative electrode can exhibit excellent electrochemical characteristics by further reducing the interfacial resistance of the negative electrode.

[0069]

[0070] (Example 1)

[0071] A CNF solution dispersed in a non-aqueous solvent was coated onto a lithium metal surface with a thickness of 50 μm and dried. Subsequently, a zinc chloride (ZnCl2) solution dissolved in tetrahydrofuran (THF) was coated onto the CNF-coated lithium metal surface and dried. Afterward, the final coated lithium metal anode material was prepared by washing again with THF solvent and drying again. The coating content was 1 wt% for the CNF coating layer and 9 wt% for the Zn coating layer relative to the weight of the lithium metal.

[0072]

[0073] (Example 2)

[0074] A CNT solution dispersed in a non-aqueous solvent was coated onto a lithium metal surface with a thickness of 50 μm and dried. Subsequently, a zinc chloride (ZnCl2) solution dissolved in THF was coated onto the CNT-coated lithium metal surface and dried. Afterward, the final coated lithium metal anode material was prepared by washing again with THF solvent and drying again. The coating content was 1 wt% for the CNT coating layer and 9 wt% for the Zn coating layer relative to the weight of the lithium metal.

[0075]

[0076] (Example 3)

[0077] A CNT solution dispersed in a non-aqueous solvent was coated onto a lithium metal surface with a thickness of 50 μm and dried. Subsequently, a solution of zinc chloride (ZnCl2) and silver chloride (AgCl3) dissolved in THF at a 1:1 ratio was coated onto the CNT-coated lithium metal surface and dried. Afterward, the final coated lithium metal anode material was prepared by washing again with THF solvent and drying again. The coating content was 1 wt% for the CNT coating layer and 9 wt% for the Zn-Ag mixed coating layer relative to the weight of the lithium metal.

[0078]

[0079] (Example 4)

[0080] A CNT solution dispersed in a non-aqueous solvent was coated onto a lithium metal surface with a thickness of 50 μm and dried. Subsequently, a solution of zinc chloride (ZnCl2) and silicon chloride (SiCl4) dissolved in THF at a 1:1 ratio was coated onto the CNT-coated lithium metal surface and dried. Afterward, the final coated lithium metal anode material was prepared by washing again with THF solvent and drying again. The coating content was 1 wt% for the CNT coating layer and 9 wt% for the Zn-Si coating layer relative to the weight of the lithium metal. The battery evaluation was conducted in the same manner as in Example 1.

[0081]

[0082] (Comparative Example 1)

[0083] The experiment was conducted in the same manner as Example 1, except that no CNF was coated.

[0084]

[0085] (Comparative Example 2)

[0086] The procedure was carried out in the same manner as Example 1, except that ZnCl2 was not coated.

[0087]

[0088] (Experimental Example)

[0089] A 2032-sized coin symmetric cell was fabricated by cutting the cathode material into a circular shape with a diameter of 16 mm, and electrochemical characteristics were evaluated using a charge / discharger. The charge / discharge rate was 2 mA / cm², and the termination condition was 1 mAh / cm². The battery life was calculated by determining the time taken to reach the end of life when the overvoltage reached 0.2 V. Coin cell interfacial resistance was measured 1 hour after cell fabrication using an impedance meter (Wonatech ZIVE SP1). The measurement conditions were an amplitude of 10 mV and a frequency range of 1 MHz to 0.1 Hz at the open circuit voltage, and the measurement was performed in a 25°C constant temperature chamber.

[0090]

[0091] Interface resistance (Ω) 1 hour after battery manufacturing Battery life (hours) Example 1 12095 Example 2 73136 Example 3 57155 Example 4 84130 Comparative Example 1 25085 Comparative Example 2 48067

[0092] Table 1 shows the results of evaluating batteries manufactured using the examples and comparative examples according to the experimental examples. Overall, it can be seen that the interface resistance of the negative electrode and the battery life of Examples 1 to 4, in which multiple coating layers were formed on the lithium metal, were improved compared to Comparative Examples 1 and 2, in which a single coating layer was formed on the lithium metal. In addition, it can be seen that the interface resistance and battery life of Example 2, which includes a CNT carbon coating layer, were improved compared to Example 1, which includes a carbon coating layer containing CNF. Meanwhile, in the case of Example 3, in which a lithium-affinity material containing zinc (Zn) and silver (Ag) was coated on a carbon coating layer containing CNT, it can be seen that the interface resistance and battery life were significantly improved compared to the remaining examples and comparative examples.

[0093] As a result, the cathode material according to the embodiment of the present invention has a triple layer comprising a carbon coating layer and a lithium-affinity material coating layer disposed on the surface of a lithium metal, thereby reducing the interfacial resistance of the lithium metal and improving lifespan characteristics, and a secondary battery including the cathode material according to the embodiment of the present invention can have improved lifespan characteristics and exhibit excellent electrochemical characteristics.

Claims

1. Layer 1; A second layer disposed on one side of the first layer; and It includes a third layer disposed on the other side opposite to the side on which the first layer of the second layer is disposed, and The first layer comprises lithium metal, the second layer comprises carbon, and the third layer comprises a lithium-affinity material. Cathode material.

2. In Paragraph 1, The above lithium-affinity material comprises a metal or a metal oxide, Cathode material.

3. In Paragraph 1, The content of the second layer is 0.001 wt% to 10 wt% relative to the weight of the first layer, cathode material 4. In Paragraph 1, The content of the third layer is 0.001 wt% to 20 wt% relative to the weight of the first layer, cathode material 5. Layer 1; A second layer disposed on one side of the first layer; A third layer disposed on the other side opposite to the side on which the first layer of the second layer is disposed; and A fourth layer disposed on the other side opposite to the side on which the second layer of the third layer is disposed; comprising The first layer comprises lithium metal, the second layer comprises a lithium-affinity material, the third layer comprises carbon, and the fourth layer comprises a lithium-affinity material. Cathode material.

6. A secondary battery comprising the negative electrode material of any one of paragraphs 1 to 5.

Images