Anode material and secondary battery comprising same

Abstract

One embodiment of the present invention for accomplishing the described objective relates to: an anode material comprising a first layer that contains lithium metal and micro-sized particles positioned on one surface of the first layer; and a secondary battery comprising same. The anode material includes lithium metal treated with powder-type particles on the surface, thereby having very low surface resistance and improved lifetime 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 offer very high capacity, are very lightweight, and can generate higher energy with a low redox voltage. However, lithium metal anodes exhibit high interfacial resistance due to arbitrary films on their surface, and uneven lithium ion deposition can lead to localized lithium ion accumulation and the formation of dendrites. This can result in internal short circuits and safety issues. Furthermore, the SEI film formed by the reaction with the electrolyte during lithium deposition can cause problems such as very low charge / discharge efficiency and reduced lifespan characteristics.

[0003] The negative electrode material comprising surface-treated lithium metal according to the embodiments of the present invention has very low surface resistance and can have improved lifespan characteristics.

[0004] One embodiment of the present invention for achieving the above-described purpose discloses a cathode material comprising a first layer comprising lithium metal and micro-sized particles located on one surface of the first layer.

[0005] 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 4.

[0006] The cathode material according to an embodiment of the present invention comprises lithium metal treated with powder-shaped particles on its surface, thereby having very low surface resistance and improved lifespan characteristics.

[0007] Figure 1 is a photograph of the surface of a cathode material according to one embodiment of the present invention taken with an SEM.

[0008] Figure 2 is a SEM image of the surface of an untreated cathode material.

[0009] Figure 3 is a photograph of the surface of a cathode material according to another embodiment of the present invention taken with an SEM.

[0010] Figure 4 is an EDS graph for the surface of the cathode material of Figure 3.

[0011] One embodiment of the present invention for achieving the above-described purpose discloses a cathode material comprising a first layer comprising lithium metal and micro-sized particles located on one surface of the first layer.

[0012] In this embodiment, the particle may include one or more selected from silicon (Si), zinc (Zn), carbon (C), and oxygen (O).

[0013] In this embodiment, the particles include silicon (Si) and zinc (Zn), the silicon (Si) may be included in an amount of 0.01 at% to 5 at%, and the zinc (Zn) may be included in an amount of 0.1 at% to 30 at%.

[0014] In the present embodiment, the particles include silicon (Si), zinc (Zn), carbon (C), and oxygen (O), wherein the carbon (C) is included in an amount of 10 at% to 50 at%, the oxygen (O) is included in an amount of 30 at% to 80 at%, the silicon (Si) is included in an amount of 0.01 at% to 5 at%, and the zinc (Zn) is included in an amount of 0.1 at% to 30 at%.

[0015] 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 4.

[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] (Cathode material)

[0023] A cathode material according to one embodiment of the present invention includes a first layer, and micro-sized particles may be uniformly distributed on one surface of the first layer.

[0024] The first layer may include lithium metal, and the lithium metal may include a thin film.

[0025] Powder particles can be treated on the surface of the first layer so that micro-sized particles are uniformly distributed, and as a specific example, particles within 10 μm can be uniformly distributed on one side of the first layer.

[0026] The particles may include one or more selected from silicon (Si), zinc (Zn), carbon (C), and oxygen (O), and as a specific example, the particles may include Si and Zn. In this case, Si may be processed on one surface of the first layer with a content of 0.01 at% to 5 at% and Zn may be processed with a content of 0.1 at% to 30 at%, so as to be uniformly distributed on one surface of the first layer.

[0027] FIG. 1 is a photograph of the surface of a cathode material according to one embodiment of the present invention taken with an SEM, and FIG. 2 is a photograph of the surface of an untreated cathode material taken with an SEM.

[0028] Referring to FIG. 1 and FIG. 2, in the case of the cathode material of FIG. 2, where nothing is treated on one side of the first layer, it can be seen that the surface is formed smoothly, and in the case of FIG. 1, where micro-sized particles are treated on one side of the first layer, it can be seen that the surface of the first layer is uniformly covered by the particles.

[0029] Meanwhile, a cathode material according to one embodiment of the present invention, in which particles uniformly cover the surface of the first layer, may have very low surface resistance and excellent lifespan characteristics compared to a cathode material that does not.

[0030] Meanwhile, Si and Zn covering the first layer may be lithium-affinity materials, so when the surface of the first layer is treated with Si and Zn particles, it may become a lithium alloy form through reaction with lithium during the charging and discharging process of the secondary battery described later.

[0031] Meanwhile, the surface of the cathode material according to one embodiment of the present invention is treated with particles containing a lithium-affinity material during lithium-ion electrodeposition, thereby lowering the lithium electrodeposition energy, reducing interfacial resistance, and making the lithium current uniform so as to suppress dendrite formation.

[0032] Consequently, the cathode material according to one embodiment of the present invention comprises lithium metal treated with powder-shaped particles on its surface, thereby having very low surface resistance and improved lifespan characteristics.

[0033] A cathode material according to another embodiment of the present invention includes a second layer, and micro-sized particles may be uniformly distributed on one surface of the second layer.

[0034] The second layer may include lithium metal, and the lithium metal may include a thin film.

[0035] Powder particles can be treated on the surface of the second layer so that micro-sized particles are uniformly distributed, and as a specific example, particles within 10 μm can be uniformly distributed on one side of the second layer.

[0036] The particles may include one or more selected from silicon (Si), zinc (Zn), carbon (C), and oxygen (O), and as a specific example, the particles may include silicon (Si), zinc (Zn), carbon (C), and oxygen (O). In this case, the carbon (C) content is 10 at% to 50 at%, the oxygen (O) content is 30 at% to 80 at%, the silicon (Si) content is 0.01 at% to 5 at%, and the zinc (Zn) content is 0.1 at% to 30 at%, and the particles may be processed on one surface of the second layer and uniformly distributed on one surface of the second layer.

[0037] FIG. 3 is a photograph of the surface of a cathode material according to another embodiment of the present invention taken with an SEM, and FIG. 4 is an EDS graph of the surface of the cathode material of FIG. 3.

[0038] Referring to FIGS. 3 and 4, it can be seen that particles having various particle size distributions are uniformly distributed on one surface of the second layer, and that the particle size distribution is concentrated in the range of 0.1 μm to 1.3 μm.

[0039] Meanwhile, a cathode material according to one embodiment of the present invention, in which particles uniformly cover the surface of the first layer, may have very low surface resistance and excellent lifespan characteristics compared to a cathode material that does not.

[0040] Meanwhile, Si and Zn covering the first layer may be lithium-affinity materials, so when the surface of the first layer is treated with Si and Zn particles, it may become a lithium alloy form through reaction with lithium during the charging and discharging process of the secondary battery described later.

[0041] Meanwhile, the surface of the cathode material according to one embodiment of the present invention is treated with particles containing a lithium-affinity material during lithium-ion electrodeposition, thereby lowering the lithium electrodeposition energy, reducing interfacial resistance, and making the lithium current uniform so as to suppress dendrite formation.

[0042] In addition, by surface-treating the particles to include C and O, direct contact between the electrolyte and the lithium metal is prevented, thereby preventing the formation of an SEI film and improving the charge / discharge efficiency of the secondary battery described later.

[0043] Consequently, the cathode material according to one embodiment of the present invention comprises lithium metal treated with powder-shaped particles on its surface, thereby having very low surface resistance and improved lifespan characteristics.

[0044] (Secondary battery)

[0045] A secondary battery using a negative electrode material 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.

[0046] 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.

[0047] 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 according to an embodiment of the present invention.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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 and improve lifespan by further reducing the interfacial resistance of the negative electrode.

[0055] As such, the present invention has been described with reference to an embodiment illustrated in the drawings, but this is merely illustrative, and those skilled in the art will understand that various modifications and variations of the embodiments are possible therefrom. Accordingly, the true technical scope of protection of the present invention should be determined by the technical spirit of the appended claims.

Claims

A first layer comprising lithium metal; and Micro-sized particles located on one surface of the first layer; comprising Cathode material. In paragraph 1, The above particles comprise one or more selected from silicon (Si), zinc (Zn), carbon (C), and oxygen (O), Cathode material. In paragraph 2, The above particles contain silicon (Si) and zinc (Zn), and The above silicon (Si) is included in an amount of 0.01 at% to 5 at%, and the above zinc (Zn) is included in an amount of 0.1 at% to 30 at%, Cathode material. In paragraph 2, The above particles include silicon (Si), zinc (Zn), carbon (C), and oxygen (O), and The above carbon (C) is included in an amount of 10 at% to 50 at%, the above oxygen (O) is included in an amount of 30 at% to 80 at%, the above silicon (Si) is included in an amount of 0.01 at% to 5 at%, and the above zinc (Zn) is included in an amount of 0.1 at% to 30 at%, Cathode material. A secondary battery comprising a negative electrode material according to any one of claims 1 to 4.

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