Negative electrode and lithium battery comprising same

Abstract

The invention provides a negative electrode and a lithium battery comprising the same. The negative electrode comprises a negative electrode current collector; the protective layer is arranged on one surface of the negative electrode current collector; and a negative electrode intermediate layer disposed between the negative electrode current collector and the protective layer, where the protective layer comprises a first polymer and a second polymer, the first polymer comprises a high strength polymer, the second polymer comprises an ion conductive polymer, and the negative electrode intermediate layer comprises a mixture of first particles and second particles, the first particles comprise a lithium-loving metal, and the second particles comprise a lithium-loving metal. The second particles contain a carbon element.

Description

Technical Field

[0001] One or more embodiments of this disclosure relate to a negative electrode and a lithium battery including the negative electrode. Background Technology

[0002] Currently, commercially available lithium-ion batteries primarily use negative electrode active materials such as graphite. Carbon-based negative electrode active materials do not (or substantially) change volume during charging and discharging, thus contributing to the high stability of lithium-ion batteries. Graphite, however, has a theoretical capacity as low as 372 mAh / g.

[0003] As the negative electrode, a negative electrode without a negative electrode active material layer can be used. In a negative electrode without a negative electrode active material layer, a lithium layer can be formed on the surface of the current collector during charging and discharging. In some embodiments, if the lithium layer is not uniformly formed on the surface of the current collector, lithium dendrites form and grow, leading to a short circuit between the positive and negative electrodes. As a result, the lifespan characteristics of lithium batteries including negative electrodes without a negative electrode active material layer may deteriorate.

[0004] Therefore, it is desirable to develop a method for improving the lifespan characteristics of lithium batteries, including those with a negative electrode that does not contain a negative electrode active material layer. Summary of the Invention

[0005] Technical issues One or more embodiments include a negative electrode with a novel structure.

[0006] One or more embodiments include a lithium battery comprising a negative electrode with a novel structure.

[0007] Technical solution According to one or more embodiments, the negative electrode includes: Negative electrode current collector; A protective layer is applied to one surface of the negative electrode current collector; and The negative electrode intermediate layer, located between the negative electrode current collector and the protective layer, includes: The protective layer comprises a first polymer and a second polymer, the first polymer comprising a high-strength polymer, and the second polymer comprising an ion-conducting polymer. The negative electrode intermediate layer comprises a mixture of a first particle containing a lithium-loving metal and a second particle containing carbon.

[0008] According to one or more embodiments, A lithium battery pack includes a positive electrode, a negative electrode, and an electrolyte between the positive and negative electrodes.

[0009] Beneficial effects According to one aspect of the embodiment, a lithium battery with improved cycle characteristics can be provided by including a negative electrode with a double-layer structure having a protective layer and a negative electrode intermediate layer. Attached Figure Description

[0010] Figure 1 This is a cross-sectional view of the negative electrode according to an embodiment.

[0011] Figure 2 This is a cross-sectional view of the negative electrode according to an embodiment.

[0012] Figure 3 This is a schematic diagram of a lithium battery according to an embodiment.

[0013] Figure 4 This is a schematic diagram of a lithium battery according to an embodiment.

[0014] Figure 5 This is a schematic diagram of a lithium battery according to an embodiment.

[0015] Figure 6 This is a scanning electron microscope (SEM) image of a cross-section of the negative electrode manufactured in Example 1.

[0016] Figure 7 and Figure 8 The graph shows the results of the charging and discharging experiments for Example 1 and Comparative Example 1. Detailed Implementation

[0017] During the charging and discharging process of a lithium-ion battery, which includes a protective layer and a negative electrode current collector and uses a negative electrode without a negative electrode active material layer, a lithium-containing metal layer is electrodeposited and dissolved between the negative electrode current collector and the protective layer. With repeated charging and discharging of the lithium-ion battery, the lithium-containing metal layer includes impurities remaining in the electrode and / or electrolyte decomposition products. Therefore, the presence of these impurities makes the surface of the lithium-containing metal layer rough and hard. The formation of lithium dendrites on this rough surface of the lithium-containing metal layer can induce perforation of the protective layer, and reduced adhesion between the lithium-containing metal layer and the protective layer can lead to electrolyte intrusion between the protective layer and the lithium-containing metal layer, resulting in delamination of the protective layer. With repeated charging and discharging of the lithium-ion battery, the electrolyte is essentially continuously consumed by side reactions, thus the cycle characteristics of the lithium-ion battery can deteriorate rapidly.

[0018] According to one aspect of the embodiments, the negative electrode for a lithium battery includes a bilayer structure having a protective layer and a negative electrode intermediate layer, which allows for the suppression or reduction of deformation and perforation of the protective layer, and maintains adhesion between the protective layer and lithium-containing metal deposited during charging and discharging processes to prevent or reduce delamination of the protective layer, thereby suppressing or reducing the formation of lithium dendrites and suppressing or reducing electrolyte consumption, thereby improving the cycle characteristics of the lithium battery using the negative electrode.

[0019] The subject matter of this disclosure described below can be modified in various ways and can have many examples; therefore, certain examples are shown and described in more detail in the accompanying drawings. However, this disclosure should not be construed as limited to the exemplary embodiments set forth herein, but should be understood to cover all modifications, equivalents, or alternatives falling within the scope of this disclosure.

[0020] The terminology used herein is for the purpose of describing exemplary embodiments only and is not intended to limit this disclosure. Unless it has a clearly different meaning in the context, the singular usage covers the plural usage. It will also be understood that if the terms “comprising,” “including,” and / or variations thereof are used in this specification, it indicates the presence of the stated features, regions, integrals, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, regions, integrals, steps, operations, elements, components, and / or groups thereof. The symbol “ / ” as used herein can be interpreted as “and” or “or” depending on the context.

[0021] In the accompanying drawings, thicknesses may be enlarged and / or exaggerated to clearly show the various layers and regions. Throughout the drawings and the following description, the same reference numerals may refer to the same elements. It will be understood that if an element, layer, film, segment, sheet, etc., is referred to as being "on" another element, it may be directly on said other element, or there may be intervening elements therein. Although the terms "first," "second," etc., may be used herein to describe various elements, these elements should not be limited by these terms. These terms are used only to distinguish one element from another. Components having substantially the same functional construction in this specification and the accompanying drawings are indicated by the same reference numerals and redundant descriptions may be avoided.

[0022] As used herein, the term "size" of a particle refers to, for example, the "particle diameter." If the particle is spherical, the "particle diameter" represents the average diameter; if the particle is non-spherical, the particle diameter represents the average major axis length. The particle diameter can be measured using a particle size analyzer (PSA). The particle diameter can be, for example, the average particle diameter. The average particle diameter can be, for example, the median particle diameter (D50). The median particle diameter (D50) is the size of the particles corresponding to 50% of the cumulative volume, calculated from the side of the smaller particles in a particle size distribution, such as that measured by, for example, laser diffraction.

[0023] The term "metal" as used herein includes both metals and metalloids, such as silicon and germanium in their elemental or ionic states.

[0024] As used herein, the term "alloy" refers to a mixture of two or more metals.

[0025] The term "positive electrode active material" as used herein refers to a positive electrode material capable of undergoing lithiation and delithiation.

[0026] The term "negative electrode active material" as used herein refers to a negative electrode material capable of undergoing lithiation and delithiation.

[0027] As used herein, the term "lithiation" and its variations refer to the process of adding lithium to a positive or negative electrode active material.

[0028] As used herein, the term "delithiation" and its variations refer to the process of removing lithium from positive or negative electrode active materials.

[0029] The term “charging” and its variations, as used herein, refers to the process by which a battery provides electrochemical energy.

[0030] As used herein, the term "discharge" and its variants refer to the process of removing electrochemical energy from a battery.

[0031] As used herein, the term "positive electrode" refers to the electrode in which electrochemical reduction and lithiation occur during the discharge process.

[0032] As used herein, the term "negative electrode" refers to the electrode in which electrochemical oxidation and delithiation occur during the discharge process.

[0033] The negative electrode for a lithium metal battery and the lithium battery including the negative electrode will be described in more detail below according to embodiments.

[0034] negative electrode The negative electrode for a lithium battery according to an embodiment includes: a negative electrode current collector; a protective layer on one surface of the negative electrode current collector; and a negative electrode intermediate layer between the negative electrode current collector and the protective layer, wherein the protective layer includes a first polymer and a second polymer, the first polymer including a high-strength polymer, the second polymer including an ion-conducting polymer, and the negative electrode intermediate layer including a mixture of first particles containing a lithium-philic metal and second particles containing carbon.

[0035] As described above, the negative electrode interlayer comprises a mixture of first particles containing a lithium-philic metal and second particles containing carbon. Therefore, the second particles cause the first particles containing the lithium-philic metal to be uniformly (e.g., substantially uniformly) coated on the negative electrode current collector, and the uniform (e.g., substantially uniformly) coating of the first particles on the negative electrode current collector induces a lithium-containing metal layer to be uniformly (e.g., substantially uniformly) formed between the bilayer structure comprising the protective layer and the negative electrode interlayer and the negative electrode current collector, and induces strong adhesion between the bilayer structure and the lithium-containing metal layer to prevent or reduce deformation or separation of the protective layer.

[0036] In some embodiments, the first particles are uniformly (e.g., substantially uniformly) distributed at the interface between the protective layer and the negative electrode current collector by the second particles, thereby providing a negative electrode interlayer in which the first particles are uniformly (e.g., substantially uniformly) distributed and thus uniformly (e.g., substantially uniformly) distributed lithium ions at the interface between the negative electrode interlayer and the negative electrode current collector. Therefore, local current density imbalances between the negative electrode interlayer and the negative electrode current collector are suppressed or reduced, and lithium metal can be uniformly (e.g., substantially uniformly) electrodeposited between the negative electrode interlayer and the negative electrode current collector. Due to the uniform (e.g., substantially uniformly) plating of lithium metal between the negative electrode interlayer and the negative electrode current collector, the plating and / or growth of lithium dendrites caused by local current density imbalances between the negative electrode interlayer and the negative electrode current collector can be effectively suppressed or reduced. The inclusion of both the first and second particles increases the uniformity of lithium ion distribution within the negative electrode interlayer and / or between the negative electrode interlayer and the negative electrode current collector.

[0037] In some embodiments, the negative electrode interlayer, comprising the first and second particles, exhibits higher adhesion strength to the protective layer than to the negative electrode current collector, allowing the negative electrode current collector and the negative electrode interlayer to separate (and remain separated) during charging and discharging, and enabling lithium ions to more easily flow into the region between the negative electrode current collector and the negative electrode interlayer. Therefore, a lithium-containing metal layer can be more easily formed between the negative electrode current collector and the negative electrode interlayer. In some embodiments, the negative electrode interlayer can improve the adhesion between the lithium-containing metal layer and the protective layer, thereby preventing or reducing detachment of the protective layer during battery charging and discharging.

[0038] Reference Figure 1 The negative electrode 20 includes: a negative electrode current collector 21; a protective layer 24 on the negative electrode current collector 21; and a negative electrode intermediate layer 22 between the negative electrode current collector 21 and the protective layer 24, wherein the protective layer 24 includes a first polymer comprising a high-strength polymer and a second polymer comprising an ion-conducting polymer, and the negative electrode intermediate layer 22 includes a mixture of a first particle comprising a lithiophilic metal and a second particle comprising carbon.

[0039] Reference Figure 2 The negative electrode 20 includes: a negative electrode current collector 21; a protective layer 24 on the negative electrode current collector 21; a negative electrode intermediate layer 22 between the negative electrode current collector 21 and the protective layer 24; and a metal layer 23 between the negative electrode intermediate layer 22 and the negative electrode current collector 21, wherein the protective layer 24 includes a first polymer comprising a high-strength polymer and a second polymer comprising an ion-conducting polymer, the negative electrode intermediate layer 22 includes a mixture of first particles comprising a lithiophilic metal and second particles comprising carbon elements, and the metal layer 23 includes a lithiophilic metal.

[0040] Negative electrode: Negative electrode intermediate layer Reference Figure 1 The negative electrode 20 may include a negative electrode intermediate layer 22 between the negative electrode current collector 21 and the protective layer 24. (See reference...) Figure 2 The negative electrode 20 may include a negative electrode intermediate layer 22 between the protective layer 24 and the metal layer 23. Because the negative electrode 20 includes a negative electrode intermediate layer, the generation and / or growth of lithium dendrites in the negative electrode 20 can be more effectively suppressed or reduced.

[0041] The negative electrode intermediate layer 22 may include, for example, a mixture of a first particle containing a lithium-loving metal and a second particle containing carbon.

[0042] The lithium-affinity metal included in the first particle can be a material capable of lithiation and delithiation. The negative electrode interlayer 22 can be formed by introducing the lithium-affinity metal onto the negative electrode current collector 21 via nanoparticle casting. In some embodiments, nanoparticle casting is performed by applying a slurry (dispersion solution) onto the negative electrode current collector 21 using a doctor blade, in which the first and second particles are mixed together and dispersed in a solvent. If the negative electrode interlayer 22 is introduced onto the negative electrode current collector 21 via nanoparticle casting, lithium ions permeate the negative electrode interlayer 22 to form lithium metal between the negative electrode interlayer 22 and the negative electrode current collector 21.

[0043] The first particle included in the negative electrode interlayer 22 may be a lithium-affinity metal nanoparticle. The average particle size of the first particle may be, for example, about 10 nm to about 4 μm, about 10 nm to about 1 μm, about 10 nm to about 500 nm, about 10 nm to about 100 nm, or about 20 nm to about 80 nm. If the first particle has an average particle size within these ranges, reversible electroplating and / or dissolution of lithium can be more easily performed during charging and discharging. In some embodiments, because the first particle has a nanoscale size, lithium ions penetrate the negative electrode interlayer 22 including the first particle, thus lithium metal can be deposited between the negative electrode current collector 21 and the negative electrode interlayer 22. The average particle size of the first particle is, for example, the median particle size (D50) measured using a laser-type (or laser-based) particle size analyzer.

[0044] In some embodiments, the lithiophilic metal may include at least one selected from gold (Au), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi), tin (Sn), magnesium (Mg), and zinc (Zn). The lithiophilic metal may include, for example, silver (Ag).

[0045] The second particle can be uniformly (e.g., substantially uniformly) coated onto the negative electrode current collector 21. The second particle, containing carbon, can be uniformly (e.g., substantially uniformly) coated onto the first particle on the negative electrode current collector 21, such that the first particle can be uniformly (e.g., substantially uniformly) coated onto the negative electrode current collector 21. The uniform (e.g., substantially uniformly) coating of the first particle allows lithium metal to be uniformly (e.g., substantially uniformly) plated onto the negative electrode current collector 21, preventing or reducing the formation of lithium dendrites.

[0046] The second particle may include, for example, amorphous carbon, crystalline carbon, or a combination thereof. The second particle may include, for example, amorphous carbon.

[0047] Amorphous carbon can include, for example, carbon black (CB), acetylene black (AB), furnace black (FB), Ketjen black (KB), graphene, carbon nanotubes, or combinations thereof. Amorphous carbon is carbon that is non-crystalline or has very low crystallinity, and is distinguished from crystalline carbon or graphitic carbon.

[0048] In some embodiments, the negative electrode interlayer 22 comprises a mixture of first particles containing a lithium-philic metal and second particles containing carbon, wherein the first particles are uniformly (e.g., substantially uniformly) coated onto the negative electrode current collector 21 by the second particles, and the first particles allow lithium metal to be uniformly (e.g., substantially uniformly) deposited between the negative electrode interlayer 22 and the negative electrode current collector 21. Therefore, the formation of lithium dendrites can be suppressed or reduced, and the lifespan characteristics of the lithium battery including the negative electrode 20 can be improved. In some embodiments, the negative electrode interlayer 22 firmly attaches the deposited lithium metal to a protective layer 24, which will be further described below, thereby preventing or reducing deformation and puncture of the protective layer 24 due to uneven deposition of lithium metal.

[0049] The mixing ratio of the mixture of the first and second particles included in the negative electrode intermediate layer 22 is a weight ratio and can be, for example, 10:1 to 1:10, 10:1 to 1:1, 10:1 to 2:1, 5:1 to 1:5, 5:1 to 1:1 or 5:1 to 2:1.

[0050] The negative electrode interlayer 22 may also include an adhesive. The adhesive included in the negative electrode interlayer 22 may be, for example, polyacrylic acid, carboxymethyl cellulose (CMC), styrene-butadiene rubber (SBR), polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, vinylidene fluoride / hexafluoropropylene copolymer, polyacrylonitrile, polymethyl methacrylate, etc., but is not limited thereto, and may be any suitable adhesive commonly used in the art. The adhesive may include a single adhesive or a variety of different adhesives. If the negative electrode interlayer 22 does not contain an adhesive, the negative electrode interlayer 22 may be easily separable from the protective layer 24 or the negative electrode current collector 21. Based on the total weight of the negative electrode interlayer 22, the amount of adhesive included in the negative electrode interlayer 22 may be, for example, 55 wt% or less, about 0.1 wt% to about 50 wt%, about 0.1 wt% to about 20 wt%, or about 0.1 wt% to about 10 wt%.

[0051] The thickness of the negative electrode interlayer can be, for example, about 0.1 μm to about 5 μm, about 0.1 μm to about 3 μm, about 0.5 μm to about 5 μm, about 0.5 μm to about 3 μm, or about 0.5 μm to about 2 μm. If the thickness of the negative electrode interlayer is too small, lithium dendrites formed between the negative electrode interlayer and the negative electrode current collector may cause the negative electrode interlayer to collapse, and the cycle characteristics of the lithium battery may not be improved. If the thickness of the negative electrode interlayer is excessively increased, the energy density of the lithium battery using the negative electrode 20 may decrease, and the cycle characteristics may not be improved. For example, if the thickness of the negative electrode interlayer is reduced, the charging capacity of the negative electrode interlayer may also decrease. The charging capacity of the negative electrode interlayer can be, for example, about 0.1% to about 50%, about 1% to about 30%, about 1% to about 10%, about 1% to about 5%, or about 1% to about 2% of the total charging capacity. If the charging capacity of the negative electrode interlayer is too small, lithium dendrites formed between the negative electrode interlayer and the negative electrode current collector may cause the negative electrode interlayer to collapse, and may not improve the cycle characteristics of the lithium battery. If the charging capacity of the negative electrode interlayer is excessively increased, the energy density of the lithium battery using negative electrode 20 may decrease, and may not improve the cycle characteristics.

[0052] The charging capacity of the positive electrode active material layer is obtained by multiplying the charging capacity density (mAh / g) of the positive electrode active material by the mass of the positive electrode active material in the layer. If several types (or varieties) of positive electrode active materials are used, the equation of charging capacity density × mass value is applied to each positive electrode active material, and the sum of these values ​​is the charging capacity of the positive electrode active material layer.

[0053] The charging capacity of the negative electrode intermediate layer is calculated in the same way. The charging capacity of the negative electrode intermediate layer is obtained by multiplying the charging capacity density (mAh / g) of the negative electrode active material by the mass of the negative electrode active material in the negative electrode intermediate layer. If several types (or varieties) of negative electrode active materials are used, the equation of charging capacity density × mass value is applied to each negative electrode active material, and the sum of these values ​​is the charging capacity of the negative electrode intermediate layer. Here, the charging capacity densities of the positive and negative electrode active materials are the capacities evaluated using an all-solid-state half-cell cell with lithium metal as the counter electrode. The charging capacity of the positive electrode active material layer and the negative electrode intermediate layer is directly measured by measuring the charging capacity using an all-solid-state half-cell cell. The charging capacity density is obtained by dividing the measured charging capacity by the mass of each active material. In some embodiments, the charging capacity of the positive electrode active material layer and the negative electrode intermediate layer may be the initial charging capacity measured during the first charge cycle.

[0054] Negative electrode: Protective layer Reference Figure 1 and Figure 2 The negative electrode 20 includes: a negative electrode current collector 21; a protective layer 24 on the negative electrode current collector 21; and a negative electrode intermediate layer 22 between the negative electrode current collector 21 and the protective layer 24.

[0055] The protective layer 24 may include a first polymer comprising a high-strength polymer and a second polymer comprising an ion-conducting polymer. If the protective layer 24 does not include the first and second polymers, the protective layer 24 may be easily separable from the negative electrode intermediate layer 22 and / or the negative electrode current collector 21.

[0056] The first polymer may include a high-strength polymer having a larger elastic modulus than the second polymer. The high-strength polymer has a large elastic modulus, and during the process of providing the metal layer 23 between the negative electrode current collector 21 and the negative electrode intermediate layer 22, even if lithium dendrites are formed due to partially uneven plating of lithium metal, the protective layer 24 including the high-strength polymer can be compressed on the formed metal layer 23 without (or substantially without) deformation, thus suppressing or reducing the formation of lithium dendrites.

[0057] The first polymer can be, for example, a fluoropolymer. Fluoropolymers can be, for example, polytetrafluoroethylene, polyvinylidene fluoride, vinylidene fluoride / hexafluoropropylene copolymer, and / or polyvinyl fluoride. Fluoropolymers can include, for example, polyvinylidene fluoride.

[0058] The second polymer comprises an ion-conducting polymer. Because the protective layer 24 comprises an ion-conducting polymer, the protective layer 24 can selectively allow lithium ions included in the electrolyte to pass through and effectively suppress or reduce side reactions of the organic solvent.

[0059] Ion-conducting polymers may include, for example, polyethylene oxide (PEO), polyethylene glycol (PEG), polyacrylonitrile (PAN), polyethylene dioxythiophene (PEDOT), polypyrrole (PPY), polyacrylonitrile (PAN), polyaniline, polyacetylene, or combinations thereof. Ion-conducting polymers may include, for example, polyethylene oxide (PEO).

[0060] The amount of the first polymer can be greater than or equal to the amount of the second polymer. The ratio of the first polymer to the second polymer can be, for example, 50:50 to 99:1. If the amount of the first polymer is greater than or equal to the amount of the second polymer, the protective layer 24 has sufficient elastic strength and ionic conductivity and can therefore more effectively suppress or reduce the formation of lithium dendrites.

[0061] The ratio of the first polymer to the second polymer can be, for example, 60:40 to 99:1, 70:30 to 99:1, 80:20 to 99:1, or 85:15 to 95:5.

[0062] The weight-average molecular weight of each of the first and second polymers may be from about 300,000 Daltons to about 1,000,000 Daltons or from about 400,000 Daltons to about 600,000 Daltons. In some embodiments, the weight-average molecular weight of the first and second polymers may be measured on a polystyrene standard sample using gel permeation chromatography (GPC).

[0063] According to another embodiment, the protective layer 24 is lithium salt-free and may be non-porous. The absence of lithium salt in the protective layer 24 prevents or reduces the reduction in lithium battery life due to side reactions between the lithium salt included in the protective layer 24 and the electrolyte. In some embodiments, the protective layer 24 comprises a non-porous structure, and compared to a protective layer 24 with a porous structure, it is easier to prevent or reduce deformation and perforation of the protective layer 24 due to lithium dendrites that may occur during the process of plating lithium between the negative electrode intermediate layer 22 and the negative electrode current collector 21.

[0064] The thickness of the protective layer 24 can be, for example, about 100 nm to about 20 μm, about 500 nm to about 20 μm, about 1 μm to about 20 μm, about 1 μm to about 15 μm, or about 1 μm to about 10 μm. If the protective layer 24 has a thickness within these ranges, electrolyte decomposition can be effectively suppressed or reduced, and local current density imbalances can be suppressed or reduced, thereby effectively preventing or reducing the formation and / or growth of lithium dendrites. Therefore, the cycle characteristics of the lithium battery including the protective layer 24 can be further improved. If the thickness of the protective layer 24 is excessively increased, the energy density of the lithium metal battery may decrease. If the thickness of the protective layer 24 is excessively decreased, the improvement in the cycle characteristics of the lithium metal battery may not be significant.

[0065] The thickness of the negative electrode intermediate layer 22 can be less than or equal to the thickness of the protective layer 24. The thickness ratio of the negative electrode intermediate layer 22 to the protective layer 24 can be, for example, 1:1 to 1:20, 1:1 to 1:15, 1:1 to 1:10, 1:1 to 1:5, 1:2 to 1:20, 1:2 to 1:10, or 1:2 to 1:5. If the thickness of the negative electrode intermediate layer 22 is less than or equal to the thickness of the protective layer 24, the overall structural strength of the negative electrode 20 can be improved, and the durability of the negative electrode 20 can also be improved.

[0066] Negative electrode: Negative electrode current collector Reference Figure 1 and Figure 2 The negative electrode 20 includes a negative electrode current collector 21.

[0067] The negative electrode current collector 21 may include, for example, indium (In), copper (Cu), magnesium (Mg), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), aluminum (Al), germanium (Ge), tin (Sn), lithium (Li) and / or alloys and / or conjugates thereof.

[0068] The negative electrode current collector 21 may include, for example, a first metal substrate. The first metal substrate may include a first metal as a major component, or may be composed of the first metal. Based on the total weight of the first metal substrate, the amount of the first metal included in the first metal substrate may be, for example, 90 wt% or more, 95 wt% or more, 99 wt% or more, or 99.9 wt% or more. The first metal substrate may include, for example, materials that do not react with lithium (e.g., do not form alloys and / or compounds with lithium). The first metal may include, for example, indium (In), copper (Cu), magnesium (Mg), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), aluminum (Al), germanium (Ge), tin (Sn), lithium (Li), and / or alloys and / or conjugates thereof. The first metal substrate may include, for example, one selected from the aforementioned metals, an alloy of two or more of the aforementioned metals, and / or one of the conjugates of two or more of the aforementioned metals. The first metal substrate may be in the form of, for example, a sheet or a foil. The thickness of the negative electrode current collector 21 can be, for example, about 5 μm to about 50 μm, about 10 μm to about 50 μm, about 10 μm to about 40 μm, or about 10 μm to about 30 μm, but is not necessarily limited to these ranges. The thickness can vary depending on the target characteristics of the lithium battery.

[0069] The negative electrode current collector 21 may include, for example, a first metal substrate and a coating layer on the first metal substrate that includes a second metal. The second metal has a higher Mohs hardness than the first metal. The coating layer containing the second metal is harder than the substrate containing the first metal. Therefore, degradation of the first metal substrate can be prevented or reduced. The Mohs hardness of the material constituting the first metal substrate may be, for example, 5.5 or less. The Mohs hardness of the first metal may be, for example, 5.5 or less, 5.0 or less, 4.5 or less, 4.0 or less, 3.5 or less, or 3.0 or less. The Mohs hardness of the first metal may be, for example, from about 2.0 to about 6.0. The coating layer may include the second metal. The coating layer may include the second metal as a major component, or may be composed of the second metal. Based on the total weight of the coating layer, the amount of the second metal included in the coating layer may be, for example, 90 wt% or more, 95 wt% or more, 99 wt% or more, or 99.9 wt% or more. The coating layer may include, for example, a material that does not react with lithium (e.g., does not form alloys and / or compounds with lithium). The Mohs hardness of the material constituting the coating layer can be, for example, 6.0 or higher. For example, the Mohs hardness of the second metal can be 6.0 or greater, 6.5 or greater, 7.0 or greater, 7.5 or greater, 8.0 or greater, 8.5 or greater, or 9.0 or greater. The Mohs hardness of the second metal can be, for example, from 6.0 to 12. If the Mohs hardness of the second metal is too low, it may be difficult to suppress or reduce the degradation of the negative electrode current collector. If the Mohs hardness of the second metal is too high, processing may be difficult (or may be too challenging). The second metal can be, for example, at least one selected from titanium (Ti), manganese (Mn), niobium (Nb), tantalum (Ta), iridium (Ir), vanadium (V), rhenium (Re), osmium (Os), tungsten (W), chromium (Cr), boron (B), ruthenium (Ru), and rhodium (Rh). The coating layer can include, for example, an alloy of one and / or two or more of the aforementioned metals. The difference between the Mohs hardness of the first metal included in the first metal substrate and the Mohs hardness of the second metal included in the coating layer can be, for example, 2 or greater, 2.5 or greater, 3 or greater, 3.5 or greater, or 4 or greater. If the first metal and the second metal have such a Mohs hardness difference, the degradation of the negative electrode current collector can be more effectively suppressed or reduced. The coating layer can have a single-layer structure or a multilayer structure with two or more layers. The coating layer can have a two-layer structure, for example, including a first coating layer and a second coating layer. The coating layer can have a three-layer structure, for example, including a first coating layer, a second coating layer, and a third coating layer. The thickness of the coating layer can be, for example, about 10 nm to about 1 μm, about 50 nm to about 500 nm, about 50 nm to about 200 nm, or about 50 nm to about 150 nm. If the thickness of the coating layer is too small, it may be difficult to suppress or reduce the uneven growth of the lithium-containing metal layer.As the thickness of the coating increases, the cycle characteristics of the lithium battery improve. However, if the coating is too thick, the energy density of the lithium battery decreases and the coating may be difficult to form (or too difficult to form). The coating can be applied to the first metal substrate by, for example, vacuum deposition, sputtering, plating, etc., but the method of applying the coating is not limited to these methods, and any suitable method commonly used in the art for applying the coating can be used.

[0070] The negative electrode current collector 21 may include, for example, a substrate film and a metal layer on one or opposite surfaces of the substrate film. The substrate film may include, for example, a polymer. The polymer may be, for example, a thermoplastic polymer. The polymer may include, for example, polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP), polybutylene terephthalate (PBT), polyimide (PI), or combinations thereof. Because the substrate film includes a thermoplastic polymer, it can liquefy in the event of a short circuit, thereby suppressing or reducing a rapid increase in current. In some embodiments, the substrate film may be an insulator (e.g., an electrical insulator). The metal layer may include, for example, indium (In), copper (Cu), magnesium (Mg), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), aluminum (Al), germanium (Ge), tin (Sn), lithium (Li), and / or alloys or conjugates thereof. The metal layer may act as an electrochemical fuse and be cut off in the event of an overcurrent to perform a short-circuit prevention or reduction function. The limiting current and the maximum current can be adjusted by adjusting the thickness of the metal layer. The metal layer can be plated and / or deposited on the substrate film. Reducing the thickness of the metal layer decreases the limiting current and / or maximum current of the negative electrode current collector, thus improving the stability of the lithium battery during short circuits. Lead tabs can be added to the metal layer for external connections. The lead tabs can be welded to the metal layer or metal layer / substrate film laminate using methods such as ultrasonic welding, laser welding, and / or spot welding. During welding, the substrate film and / or metal layer can melt, and the metal layer can be electrically connected to the lead tab. To strengthen the weld between the metal layer and the lead tab, a metal sheet can be added between the metal layer and the lead tab. The metal sheet can be a sheet of the same material as the metal layer. The metal sheet can be, for example, metal foil and / or metal mesh. The metal sheet can be, for example, aluminum foil, copper foil, and / or SUS foil. The lead tab can be welded to the metal sheet / metal layer laminate or metal sheet / metal layer / substrate film laminate by positioning the metal sheet on the metal layer and welding it to the lead tab. During soldering, the metal layer or metal layer / sheet laminate can be electrically connected to the lead patch while the substrate film, metal layer, and / or metal sheet melt. The metal sheet and / or lead patch can be added to a portion of the metal layer. The thickness of the substrate film can be, for example, about 1 μm to about 50 μm, about 1.5 μm to about 50 μm, about 1.5 μm to about 40 μm, or about 1 μm to about 30 μm. Having a thickness within these ranges allows for more effective reduction of the electrode assembly's weight. The melting point of the substrate film can be, for example, about 100°C to about 300°C, about 100°C to about 250°C, or about 100°C to about 200°C. Having a melting point within these ranges allows the substrate film to melt and readily bond to the lead patch during the soldering process.To improve adhesion between the substrate film and the metal layer, surface treatments such as corona treatment can be applied to the substrate film. The thickness of the metal layer can be, for example, about 0.01 μm to about 3 μm, about 0.1 μm to about 3 μm, about 0.1 μm to about 2 μm, or about 0.1 μm to about 1 μm. Having a metal layer within these thickness ranges ensures the stability of the electrode assembly while maintaining conductivity (e.g., electrical conductivity). The thickness of the metal sheet can be, for example, about 2 μm to about 10 μm, about 2 μm to about 7 μm, or about 4 μm to about 6 μm. Having a metal sheet within these thickness ranges makes it easier to connect the metal layer to the lead patch. If the negative electrode current collector has such a structure, the weight of the electrode can be reduced, resulting in improved energy density.

[0071] In embodiments of this disclosure, the positive current collector may include, for example, a substrate film and a metal layer on one or opposite surfaces of the substrate film. The substrate film may include, for example, a polymer. The polymer may be, for example, a thermoplastic polymer. The polymer may include, for example, polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP), polybutylene terephthalate (PBT), polyimide (PI), or combinations thereof. Because the substrate film includes a thermoplastic polymer, it can liquefy in the event of a short circuit, thereby suppressing or reducing a rapid increase in current. In some embodiments, the substrate film may be an insulator (e.g., an electrical insulator). The metal layer may include, for example, indium (In), copper (Cu), magnesium (Mg), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), aluminum (Al), germanium (Ge), and / or alloys and / or conjugates thereof. The positive current collector may include a metal sheet and / or lead terminals. The substrate film, metal layer, metal sheet, and lead terminals of the positive current collector can be understood by referring to the negative current collector. If the positive current collector has such a structure, the weight of the electrode can be reduced, and as a result, the energy density can be improved.

[0072] Negative electrode: Metal layer Reference Figure 2 The negative electrode 20 may also include a metal layer 23 between the negative electrode current collector 21 and the negative electrode intermediate layer 22. The metal layer 23 may include, for example, a lithium-philic metal.

[0073] In some embodiments, the metal layer 23 may include at least one selected from gold (Au), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi), tin (Sn), and zinc (Zn). The lithiophilic metal may include, for example, silver (Ag).

[0074] The metal layer 23 may include, for example, lithium-loving metal particles. The metal layer 23 may be formed by introducing lithium-loving metal particles onto the negative electrode current collector 21 via sputtering and / or nanoparticle casting.

[0075] The lithiophilic metal particles included in the metal layer 23 can be nanoparticles of a lithiophilic metal. The average particle size of the lithiophilic metal particles can be, for example, about 10 nm to about 4 μm, about 10 nm to about 1 μm, about 10 nm to about 500 nm, about 10 nm to about 100 nm, or about 20 nm to about 80 nm. If the lithiophilic metal particles have an average particle size within these ranges, reversible electroplating and / or dissolution of lithium can be more easily performed during charging and discharging. The average particle size of the lithiophilic metal particles is, for example, the median particle size (D50) measured using a laser-type (or laser-based) particle size analyzer.

[0076] The metal layer 23 may be free of binder. Since there is no binder in the metal layer 23, the current density can be improved. Therefore, the total capacity of the lithium battery, including the negative electrode 20 containing the metal layer 23, can be increased.

[0077] lithium batteries A lithium battery pack according to an embodiment includes: a positive electrode; a negative electrode; and an electrolyte, located between the positive and negative electrodes. The lithium battery can provide both improved capacity and excellent lifespan characteristics by including a negative electrode.

[0078] The lithium battery can be, for example, a primary lithium battery, a secondary lithium battery, a lithium-sulfur battery, a lithium-air battery, etc., but is not limited to these, and can be any suitable lithium battery commonly used in the art.

[0079] Lithium batteries can be manufactured using the following example methods, but are not limited to these methods, and can be adapted to desired or required conditions.

[0080] negative electrode Prepare the above-mentioned negative electrode.

[0081] positive electrode First, a positive electrode active material composition is prepared by mixing a positive electrode active material, a conductive agent, a binder, and a solvent together. The prepared positive electrode active material composition is then directly coated onto an aluminum current collector and dried to prepare a positive electrode plate having a positive electrode active material layer formed thereon. In some embodiments, the positive electrode active material composition can be cast onto a separate support, and then a film layer obtained by peeling it from the support is pressed onto the aluminum current collector to prepare a positive electrode plate with a positive electrode active material layer.

[0082] The positive electrode active material is a lithium-containing metal oxide, and any suitable material commonly used in the art can be used without limitation. For example, a composite oxide of lithium with one or more types (or kinds) of metals selected from cobalt, manganese, nickel, and combinations thereof can be used, and examples can be compounds represented by one of the following: Li a A 1-b B b D2 (where 0.90≤a≤1 and 0≤b≤0.5); Li a E 1-b B b O 2-c D c (Where, 0.90≤a≤1, 0≤b≤0.5, and 0≤c≤0.05); LiE 2-b B b O 4-c D c (Where, 0 ≤ b ≤ 0.5, and 0 ≤ c ≤ 0.05); Li a Ni 1-b-c Co b B c D α (Where, 0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05, and 0<α≤2); Li a Ni 1-b-c Co b B c O 2-α F α (Where, 0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05, and 0<α<2); Li a Ni 1-b-c Co b B c O 2-α F2 (where 0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05, and 0<α<2); Li a Ni 1-b-c Mn b B c D α (Where, 0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05, and 0<α≤2); Li a Ni 1-b-c Mn b B c O 2-α F α (Where, 0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05, and 0<α<2); Li a Ni 1-b-c Mnb B c O 2-α F2 (where 0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05, and 0<α<2); Li a Ni b E c G d O2 (where 0.90≤a≤1, 0≤b≤0.9, 0≤c≤0.5, and 0.001≤d≤0.1); Li a Ni b Co c Mn d G e O2 (where 0.90≤a≤1, 0≤b≤0.9, 0≤c≤0.5, 0≤d≤0.5, and 0.001≤e≤0.1); Li a NiG b O2 (where 0.90≤a≤1 and 0.001≤b≤0.1); Li a CoG b O2 (where 0.90≤a≤1 and 0.001≤b≤0.1); Li a MnG b O2 (where 0.90≤a≤1 and 0.001≤b≤0.1); Li a Mn2G b O4 (where 0.90≤a≤1 and 0.001≤b≤0.1); QO2; QS2; LiQS2; V2O5; LiV2O5; LiIO2; LiNiVO4; Li (3-f) J2(PO4)3 (0≤f≤2); Li (3-f) Fe2(PO4)3 (0≤f≤2); and LiFePO4.

[0083] In the chemical formulas representing these compounds, A is Ni, Co, Mn, or a combination thereof; B is Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, a rare earth element, or a combination thereof; D is O, F, S, P, or a combination thereof; E is Co, Mn, or a combination thereof; F is F, S, P, or a combination thereof; G is Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, or a combination thereof; Q is Ti, Mo, Mn, or a combination thereof; I is Cr, V, Fe, Sc, Y, or a combination thereof; and J is V, Cr, Mn, Co, Ni, Cu, or a combination thereof. Compounds in which a coating layer is provided on the surface of these compounds can be used, and mixtures of these compounds and compounds including a coating layer can also be used. The coating layer provided on the surface of these compounds can include a coating element compound, such as an oxide of the coating element, a hydroxide of the coating element, a hydroxyoxide of the coating element, a carbonate oxide of the coating element, or a hydroxycarbonate of the coating element. The compound constituting the coating layer can be amorphous or crystalline. The coating element included in the coating layer can be Mg, Al, Co, K, Na, Ca, Si, Ti, V, Sn, Ge, Ga, B, As, Zr, or a mixture thereof. The method of providing the coating layer can be selected within a range that does not (or substantially does not) adversely affect the physical properties of the positive electrode active material. The coating method can be, for example, spraying and / or dipping methods, etc. A detailed description of the coating method is not required here, as it should be apparent to those of ordinary skill in the art after reading this disclosure.

[0084] The positive electrode active material can be, for example, Li a Ni x Co y M z O 2-b A b (1.0 ≤ a ≤ 1.2, 0 ≤ b ≤ 0.2, 0.8 ≤ x < 1, 0 < y ≤ 0.3, 0 < z ≤ 0.3, x + y + z = 1, M is manganese (Mn), niobium (Nb), vanadium (V), magnesium (Mg), gallium (Ga), silicon (Si), tungsten (W), molybdenum (Mo), iron (Fe), chromium (Cr), copper (Cu), zinc (Zn), titanium (Ti), aluminum (Al), boron (B), or a combination thereof, and A is F, S, Cl, Br, or a combination thereof), LiNi[[ID=ID=16]] x Co y Mn z O2 (0.8 ≤ x ≤ 0.95, 0 ≤ y ≤ 0.2, 0 < z ≤ 0.2, and x + y + z = 1), LiNi x Co y Al zO2 (0.8 ≤ x ≤ 0.95, 0 ≤ y ≤ 0.2, 0 < z ≤ 0.2, and x + y + z = 1), LiNi x Co y Mn z Al w O2 (0.8 ≤ x ≤ 0.95, 0 ≤ y ≤ 0.2, 0 < z ≤ 0.2, 0 < w ≤ 0.2, and x + y + z + w = 1), Li a Co x M y O 2-b A b (1.0 ≤ a ≤ 1.2, 0 ≤ b ≤ 0.2, 0.9 ≤ x ≤ 1, 0 ≤ y ≤ 0.1, and x + y = 1, M is manganese (Mn), niobium (Nb), vanadium (V), magnesium (Mg), gallium (Ga), silicon (Si), tungsten (W), molybdenum (Mo), iron (Fe), chromium (Cr), copper (Cu), zinc (Zn), titanium (Ti), aluminum (Al), boron (B) or a combination thereof, and A is F, S, Cl, Br or a combination thereof), Li a Ni x Mn y M’ z O 2-b A b (1.0 ≤ a ≤ 1.2, 0 ≤ b ≤ 0.2, 0 < x ≤ 0.3, 0.5 ≤ y < 1, 0 < z ≤ 0.3, and x + y + z = 1, M’ is cobalt (Co), niobium (Nb), vanadium (V), magnesium (Mg), gallium (Ga), silicon (Si), tungsten (W), molybdenum (Mo), iron (Fe), chromium (Cr), copper (Cu), zinc (Zn), titanium (Ti), aluminum (Al), boron (B) or a combination thereof, and A is F, S, Cl, Br or a combination thereof), Li a M1 x M2 y PO 4-b X b (where 0.90 ≤ a ≤ 1.1, 0 ≤ x ≤ 0.9, 0 ≤ y ≤ 0.5, 0.9 < x + y < 1.1, and 0 ≤ b ≤ 2, M1 is chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zirconium (Zr) or a combination thereof, and M2 is magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), titanium (Ti), zinc (Zn), boron (B), niobium (Nb), gallium (Ga), indium (In), molybdenum (Mo), tungsten (W), aluminum (Al), silicon (Si), chromium (Cr), vanadium (V), scandium (Sc), yttrium (Y) or a combination thereof, and X is O, F, S, P or a combination thereof) and Li a M3 zPO4 (0.90≤a≤1.1, 0.9≤z≤1.1, and M3 is chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zirconium (Zr) or a combination thereof) is represented.

[0085] Examples of conductive agents include: carbon black, graphite particles, natural graphite, synthetic graphite, acetylene black, Ketjen black, carbon fibers, carbon nanotubes; metal powders or fibers or tubes of metals (such as copper, nickel, aluminum, silver); and conductive polymers, such as, but not limited to, polyphenylene derivatives, and any suitable material commonly used in the art as a conductive material may be used herein. In some embodiments, the positive electrode may not include, for example, a separate conductive agent.

[0086] The binder may be vinylidene fluoride / hexafluoropropylene copolymer, polyvinylidene fluoride, polyacrylonitrile, polymethyl methacrylate, polytetrafluoroethylene (PTFE), mixtures of these polymers, styrene-butadiene rubber polymers, etc. The solvent may be N-methylpyrrolidone (NMP), acetone, water, etc. However, the binder and solvent are not limited to these and may be any suitable binder and / or solvent commonly used in the art.

[0087] Plasticizers or pore-forming agents can be added to the positive electrode active material composition to form pores in the electrode plate.

[0088] The amounts of the positive electrode active material, conductive agent, binder, and solvent used in the positive electrode are at any suitable level typically used in lithium batteries. Depending on the application and construction of the lithium battery, one or more of the conductive agent, binder, and solvent may be omitted.

[0089] The amount of binder included in the positive electrode may be from about 0.1 wt% to about 10 wt% or from about 0.1 wt% to about 5 wt% of the total weight of the positive electrode active material layer. The amount of positive electrode active material included in the positive electrode may be from about 80 wt% to about 99 wt%, from about 90 wt% to about 99 wt%, or from about 95 wt% to about 99 wt% of the total weight of the positive electrode active material layer.

[0090] diaphragm Next, a separator will be prepared to be inserted between the positive and negative electrodes.

[0091] For the separator, any suitable separator commonly used in lithium batteries can be used. For example, any suitable separator that has low resistance to ion migration of the electrolyte and excellent wettability to the liquid electrolyte can be used. The separator can be a non-woven and / or woven fabric selected from at least one of glass fiber, polyester, Teflon, polyethylene, polypropylene, polytetrafluoroethylene (PTFE), and combinations thereof. For lithium-ion batteries, rollable separators (such as polyethylene and polypropylene) can be used; for lithium-ion polymer batteries, separators with excellent wettability to organic liquid electrolytes can be used.

[0092] The membrane is manufactured using the example method described below, but the disclosure is not limited to this method and can be adapted to desired or required conditions.

[0093] First, a membrane composition is prepared by mixing a polymer resin, filler, and solvent together. The membrane composition is then directly coated onto an electrode and dried to form a membrane. In some embodiments, after casting the membrane composition onto a support and drying it, a membrane peeled from the support is laminated onto the electrode to form a membrane.

[0094] There are no particular limitations on the polymers used to manufacture the diaphragm, and any suitable polymer commonly used in the art as an adhesive for electrode plates can be used. For example, vinylidene fluoride / hexafluoropropylene copolymer, polyvinylidene fluoride (PVDF), polyacrylonitrile, polymethyl methacrylate, or mixtures thereof can be used.

[0095] electrolytes Next, the electrolyte is prepared.

[0096] Electrolytes can be, for example, liquid electrolytes, solid electrolytes, gel electrolytes, or combinations thereof.

[0097] The electrolyte can be, for example, an organic liquid electrolyte. In an example, the organic liquid electrolyte can be prepared by dissolving a lithium salt in an organic solvent.

[0098] Any suitable organic solvent that can be used as an organic solvent in the art may be used as the organic solvent herein. The organic solvent may be, for example, propylene carbonate, ethylene carbonate, fluoroethylene carbonate, butyl carbonate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, methyl isopropyl carbonate, dipropyl carbonate, dibutyl carbonate, benzyl nitrile, acetonitrile, tetrahydrofuran, 2-methyltetrahydrofuran, γ-butyrolactone, dioxolane, 4-methyldioxolane, N,N-dimethylformamide, dimethylacetamide, dimethyl sulfoxide, dioxane, 1,2-dimethoxyethane, sulfolane, dichloroethane, chlorobenzene, nitrobenzene, diethylene glycol, dimethyl ether, or mixtures thereof.

[0099] Any suitable lithium salt can be used, provided it is commonly used as a lithium salt in the art. Examples of suitable lithium salts include, for instance, LiPF6, LiBF4, LiSbF6, LiAsF6, LiClO4, LiCF3SO3, Li(CF3SO2)2N, LiC4F9SO3, LiAlO2, LiAlCl4, and LiN(C x F 2x+1 SO2)(C y F 2y+1 SO2 (1≤x≤20, 1≤y≤20), LiCl, LiI, or mixtures thereof. The concentration of the lithium salt can be, for example, from about 0.1M to about 5.0M.

[0100] Solid electrolytes can be, for example, oxide solid electrolytes, sulfide solid electrolytes, polymer solid electrolytes, or combinations thereof.

[0101] Solid electrolytes can be, for example, oxide-based solid electrolytes. Oxide-based solid electrolytes can be selected from Pb(Zr,Ti)O3 (PZT), Pb... 1-x La x Zr 1-y Ti y O3 (PLZT) (0≤x<1, 0≤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, and x is an integer from 1 to 10) at least one of these. Solid electrolytes can be manufactured, for example, by sintering. For example, oxide-based solid electrolytes can be selected from Li7La3Zr2O. 12 (LLZO) and Li 3+x La3Zr 2-a M a O 12 Garnet system (M-doped LLZO, where M = Ga, W, Nb, Ta, or Al, and x is an integer from 1 to 10).

[0102] Sulfide-based solid electrolytes may include, for example, lithium sulfide, silicon sulfide, phosphorus sulfide, boron sulfide, or combinations thereof. Sulfide-based solid electrolytes may include Li₂S, P₂S₅, SiS₂, GeS₂, B₂S₃, or combinations thereof. Sulfide-based solid electrolytes may be Li₂S and / or P₂S₅. Sulfide-based solid electrolytes have higher lithium-ion conductivity than other inorganic compounds. For example, sulfide-based solid electrolytes include Li₂S and P₂S₅. If the sulfide-based solid electrolyte material constituting the sulfide-based solid electrolyte includes Li₂S-P₂S₅, the mixing molar ratio of Li₂S to P₂S₅ can be, for example, in the range of about 50:50 to about 90:10. In some embodiments, by using Li₃PO₄, halogens, halogen compounds, Li₂S, etc. 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 0.75 Inorganic solid electrolytes prepared by adding S4 (“thio-LISICON”) or Li2O-Al2O3-TiO2-P2O5 (“LATP”) to Li2S-P2S5, SiS2, GeS2, B2S3, or combinations thereof can be used as sulfide solid electrolytes. 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-Z m S n(0 < m < 10, 0 < n < 10, Z = Ge, Zn or Ga); Li2S - GeS2; Li2S - SiS2 - Li3PO4; and Li2S - SiS2 - Li p MO q (0 < p < 10, 0 < q < 10, M = P, Si, Ge, B, Al, Ga or In). In this regard, the sulfide - based solid electrolyte materials can be prepared by processing the raw starting materials of the sulfide - based solid electrolyte materials (e.g., Li2S, P2S5, etc.) via methods such as the melt quenching method and / or the mechanical grinding method. In some embodiments, calcination can be performed after the processing. The sulfide - based solid electrolyte can be amorphous, crystalline or a mixture thereof.

[0103] The polymer solid electrolyte can be, for example, an electrolyte comprising a mixture of a lithium salt and a polymer or a polymer having an ion - conductive functional group. The polymer solid electrolyte can be, for example, a polymer electrolyte that does not contain a liquid electrolyte. The polymers included in the polymer solid electrolyte include, for example, polyethylene oxide (PEO), polyvinylidene fluoride (PVDF), vinylidene fluoride - hexafluoropropylene (PVDF - HFP), polyethylene oxide (PEO), poly(styrene - b - ethylene oxide) block copolymer (PS - PEO), poly(styrene - butadiene), poly(styrene - isoprene - styrene), poly(styrene - b - divinylbenzene) block copolymer, poly(styrene - ethylene oxide - styrene) block copolymer, polystyrene sulfonate (PSS), polyvinyl fluoride (PVF), poly(methyl methacrylate) (PMMA), polyethylene glycol (PEG), polyacrylonitrile (PAN), polytetrafluoroethylene (PTFE), polyethylenedioxythiophene (PEDOT), polypyrrole (PPY), polyacrylonitrile (PAN), polyaniline, polyacetylene, Nafion, Aquivion, Flemion, Gore, Aciplex, Morgan ADP, sulfonated poly(ether ether ketone) (SPEEK), sulfonated poly(aryletherketonesulfone) (SPAEKKS), sulfonated poly(aryletherketone) (SPAEK), poly[bis(benzimidazolobenzoisoquinolinone)] (SPBIBI), poly(styrene sulfonic acid) (PSS), lithium 9,10 - diphenylanthracene - 2 - sulfonate (DPASLi + ), or a combination thereof, but not limited thereto, and any suitable material commonly used as a polymer electrolyte in the art can be used herein. Any suitable lithium salt can be used as long as the lithium salt can be used as a lithium salt in the art. The lithium salt can be, for example, LiPF6, LiBF4, LiSbF6, LiAsF6, LiClO4, LiCF3SO3, Li(CF3SO2)2N, LiC4F9SO3, LiAlO2, LiAlCl4, LiN(C x F2x+1 SO2)(C y F 2y+ 1SO2) (where x and y are both 1 to 20), LiCl, LiI or mixtures thereof.

[0104] Gel electrolytes are, for example, gel polymer electrolytes. In some embodiments, a gel polymer electrolyte may be an electrolyte comprising a liquid electrolyte and a polymer, or an electrolyte comprising an organic solvent and a polymer having ionicly conductive functional groups. A liquid electrolyte may be, for example, an ionic liquid, a mixture of a lithium salt and an organic solvent, a mixture of an ionic liquid and an organic solvent, or a mixture of a lithium salt, an ionic liquid, and an organic solvent. The polymer may be selected from polymers used in solid polymer electrolytes. The organic solvent may be selected from organic solvents used in liquid electrolytes. The lithium salt may be selected from lithium salts used in solid polymer electrolytes. An ionic liquid refers to a salt having a melting point below room temperature and consisting only of ions, and being liquid at room temperature or a molten salt at room temperature. In some embodiments, an ionic liquid may be selected from at least one compound comprising: a) at least one cation selected from ammonium, pyrrolidineonium, pyridinium, pyrimidineonium, imidazoleonium, piperidinium, pyrazoliumonium, oxazoliumonium, pyridazinium, phosphonium, sulfonium, triazoliumonium, and mixtures thereof; and b) a cation selected from BF4. - PF6 - AsF6 - SbF6 - AlCl4 - HSO4 - ClO4 - CH3SO3 - CF3CO2 - Cl - ,Br - I - BF4 - SO4 - CF3SO3 - (FSO2)2N - (C2F5SO2)2N - (C2F5SO2)(CF3SO2)N - and (CF3SO2)2N - At least one anion in the electrolyte. A polymer solid electrolyte can be formed by wetting the polymer solid electrolyte with a liquid electrolyte in a lithium battery. Gel electrolytes may also include inorganic particles.

[0105] lithium batteries Reference Figure 3The lithium battery 1 according to an embodiment includes a positive electrode 3, a negative electrode 2 as described above, and a separator 4. The positive electrode 3, the negative electrode 2, and the separator 4 can be wound or stacked and housed in a battery casing 5. An organic liquid electrolyte is injected into the battery casing 5 and sealed with a cover assembly 6 to complete the manufacture of the lithium battery 1. The battery casing 5 can be cylindrical, but is not limited to this shape, and can be, for example, prismatic and / or thin-film shaped.

[0106] Reference Figure 4 The lithium battery 1 according to an embodiment includes a positive electrode 3, the aforementioned negative electrode 2, and a separator 4. The separator 4 may be located between the positive electrode 3 and the negative electrode 2, and the positive electrode 3, the negative electrode 2, and the separator 4 may be wound or stacked to form a battery structure 7. The battery structure 7 is housed in a battery casing 5. Electrode terminals 8 may be included to act as electrical paths for guiding current formed in the battery structure 7 to the outside. An organic liquid electrolyte is injected into the battery casing 5 and sealed to complete the manufacture of the lithium battery 1. The battery casing 5 may have a rectangular shape, but is not limited to such a shape, and may have, for example, a cylindrical shape and / or a thin film shape.

[0107] Reference Figure 5 The lithium battery 1 according to an embodiment includes a positive electrode 3, the aforementioned negative electrode 2, and a separator 4. The separator 4 is located between the positive electrode 3 and the negative electrode 2 to form a battery structure 7. The battery structure 7 is stacked in a dual-cell structure and then housed in a battery casing 5. Electrode terminals 8 may be included to act as electrical paths for guiding current formed in the battery structure 7 to the outside. An organic liquid electrolyte is injected into the battery casing 5 and sealed to complete the manufacture of the lithium battery 1. The battery casing 5 may have a rectangular shape, but is not limited to such a shape, and may have, for example, a cylindrical shape and / or a thin-film type (or thin-film variety), etc.

[0108] The type of bag (or bag type) of lithium battery corresponds to the one in Figures 3 to 5 Lithium-ion batteries that use pouches as the battery casing. Pouch-type (or pouch-variety) lithium-ion batteries may include one or more battery structures. A separator is placed between the positive and negative electrodes to form a single cell structure. After the battery structures are stacked in a dual-cell structure, the resulting structure is wetted with an organic liquid electrolyte and then housed and sealed in a pouch, thus completing the manufacture of the pouch-type lithium-ion battery. For example, the positive electrode, negative electrode, and separator can simply be stacked and housed in a pouch as an electrode assembly. In embodiments, the positive electrode, negative electrode, and separator can be wound or stacked as an electrode assembly in the form of an electrode core and then housed in a pouch. An organic liquid electrolyte is then injected into the pouch, and the pouch is then sealed to complete the manufacture of the lithium-ion battery.

[0109] Lithium-ion batteries possess excellent lifespan and high rate capability. Due to these characteristics, lithium-ion batteries are used in electric vehicles (EVs), such as plug-in hybrid electric vehicles (PHEVs). They are also used in applications that utilize or require large amounts of electrical energy storage, such as electric bicycles and power tools.

[0110] Multiple lithium-ion batteries are stacked to form a battery module, and multiple battery modules can form a battery pack. Such a battery pack can be used in any suitable device utilizing high capacity and high output. For example, battery packs can be used in laptops, smartphones, electric vehicles, etc. A battery module may include, for example, multiple batteries and a frame for holding them. A battery pack may include, for example, multiple battery modules and busbars connecting them. Battery modules and / or battery packs may also include cooling devices. Multiple battery packs can be controlled by a battery management system. The battery management system may include the battery pack and battery control devices connected to the battery pack.

[0111] Negative electrode manufacturing method A negative electrode manufacturing method according to another embodiment includes the following steps: providing a negative electrode current collector; providing a negative electrode intermediate layer on the negative electrode current collector; and providing a protective layer on the negative electrode intermediate layer, wherein the negative electrode intermediate layer comprises a mixture of first particles containing a lithium-philic metal and second particles containing carbon, and the protective layer comprises a first polymer containing a high-strength polymer and a second polymer containing an ion-conducting polymer. Lithium-ion batteries including a negative electrode manufactured in this manner provide improved cycle characteristics.

[0112] First, a negative current collector is set up. The negative current collector can be understood by referring to the description provided above regarding the negative electrode. For example, copper foil is provided as the negative current collector.

[0113] Next, a negative electrode intermediate layer is formed on the negative electrode current collector. The negative electrode intermediate layer can be formed on the negative electrode current collector, for example, by nanoparticle casting. In some embodiments, the negative electrode intermediate layer can be formed by: preparing a first slurry by mixing a first particle and a second particle together with a solvent; coating the first slurry onto the negative electrode current collector; and drying the first slurry. The first particle and the second particle can be understood by referring to the description provided in conjunction with the negative electrode above. The solvent can be water or an organic solvent. The solvent can be, for example, N,N-dimethylacetamide, N-methylpyrrolidone (NMP), etc., but is not limited to these, and can be any suitable solvent commonly used in the art.

[0114] Next, a protective layer is formed on the negative electrode intermediate layer. The protective layer can be formed by, for example, the following steps: preparing a second slurry by mixing a first polymer, a second polymer, and a solvent; coating the second slurry onto the negative electrode intermediate layer; and drying the second slurry. The coating method is not particularly limited, and coating can be performed using a doctor blade or the like. The first polymer and the second polymer can be understood by referring to the description provided in conjunction with the negative electrode above. The solvent can be an organic solvent. The solvent can be, for example, N,N-dimethylacetamide, N-methylpyrrolidone (NMP), etc., but is not limited to these, and can be any suitable solvent commonly used in the art.

[0115] The negative electrode manufacturing method may further include introducing a metal layer between the negative electrode interlayer and the negative electrode current collector. The metal layer may include, for example, a lithium-philic metal. The metal layer may also include, for example, lithium-philic metal particles.

[0116] The method for introducing a metal layer between the negative electrode interlayer and the negative electrode current collector can be the same as the method for introducing the negative electrode interlayer. For example, a metal layer can be formed on the negative electrode current collector before the negative electrode interlayer is formed. The method for forming a metal layer on the negative electrode current collector can be the same as the method for forming a negative electrode interlayer on the negative electrode current collector. For example, a metal layer comprising lithium-philic metal particles can be formed on a metal substrate by a nanoparticle casting method. In some embodiments, a laminate can be prepared by coating and drying a composition of lithium-philic metal particles without a binder on a metal substrate.

[0117] The embodiments of this disclosure will be explained in more detail through the following examples and comparative examples. However, these examples are intended to illustrate the embodiments of this disclosure, and the scope of this disclosure is not limited thereto.

[0118] Manufacturing of negative electrodes and lithium metal batteries Example 1: Cu substrate / negative electrode intermediate layer (AgNP+C, 1:3) / protective layer (PVDF+PEO, 9:1) Anode manufacturing Ag nanoparticles and carbon black were mixed together in a 1:3 weight ratio and added after being mixed with distilled water, such that the weight of the polyacrylic acid binder was 50 wt% relative to the total weight of the solids. The mixture was then dispersed by stirring overnight at 60°C using a Thinky mixer to prepare a first slurry.

[0119] The first slurry was coated onto a copper (Cu) current collector with a thickness of 10 μm using a nanoparticle casting method, and then the solvent was removed at 65 °C for 6 hours to introduce the negative electrode intermediate layer.

[0120] Polyvinylidene fluoride (PVDF) powder (Sigma-Aldrich, average Mw of 534,000 as measured by GPC) and polyethylene oxide (PEO) powder were added to N-methylpyrrolidone (NMP, 99%, Sigma-Aldrich) at a weight ratio of 9:1, and then stirred overnight at 60°C using a stir bar to prepare a second slurry.

[0121] The second slurry was coated onto the negative electrode intermediate layer using a doctor blade, and then the solvent was removed at 60°C for 6 hours to introduce a protective layer.

[0122] A negative electrode with a structure of negative electrode current collector / negative electrode intermediate layer / protective layer was prepared.

[0123] Scanning electron microscope (SEM) images of the cross-section of the prepared negative electrode are shown in Figure 6 middle.

[0124] like Figure 6 As shown, it is confirmed that a protective layer with a double-layer structure in which the negative electrode intermediate layer is on the copper current collector and the protective layer is on the negative electrode intermediate layer is provided.

[0125] The thickness of the negative electrode intermediate layer is 3μm, and the thickness of the protective layer is 6μm.

[0126] Manufacturing of button cell batteries Button cell cells were prepared by using a lithium foil with a thickness of 20 μm as the counter electrode, placing a polypropylene separator (Celgard 3510) between the counter electrode and the negative electrode, and injecting an electrolyte.

[0127] As the electrolyte, a solution in which 0.6 M LiBF4 and 0.6 M LiDFOB are dissolved in FEC (ethylene fluoride carbonate) + DEC (diethyl carbonate) (1:2 volume ratio) is used.

[0128] Example 2: Cu substrate / negative electrode intermediate layer (AgNP+C, 1:3) / protective layer (PVDF+PEO, 8:2) Except for changing the weight ratio of PVDF to PEO included in the protective layer to 8:2, the negative electrode and button cell are manufactured in essentially the same manner as in Example 1.

[0129] Example 3: Cu substrate / negative electrode intermediate layer (AgNP+C, 1:3) / protective layer (PVDF+PEO, 7:3) Except for changing the weight ratio of PVDF to PEO included in the protective layer to 7:3, the negative electrode and button cell are manufactured in essentially the same manner as in Example 1.

[0130] Example 4: Cu substrate / negative electrode intermediate layer (AgNP+C, 1:3) / protective layer (PVDF+PEO, 6:4) Except for changing the weight ratio of PVDF to PEO included in the protective layer to 6:4, the negative electrode and button cell are manufactured in essentially the same manner as in Example 1.

[0131] Example 5: Cu substrate / negative electrode intermediate layer (AgNP+C, 1:3) / protective layer (PVDF+PEO, 5:5) Except for changing the weight ratio of PVDF to PEO included in the protective layer to 5:5, the negative electrode and button cell are manufactured in essentially the same manner as in Example 1.

[0132] Example 6: Cu substrate / negative electrode intermediate layer (AgNP+C, 1:2) / protective layer (PVDF+PEO, 9:1) Except for changing the weight ratio of Ag nanoparticles to carbon black included in the negative electrode intermediate layer to 1:2, the negative electrode and button cell are manufactured in essentially the same manner as in Example 1.

[0133] Example 7: Cu substrate / negative electrode intermediate layer (AgNP+C, 1:1) / protective layer (PVDF+PEO, 9:1) Except for changing the weight ratio of Ag nanoparticles to carbon black included in the negative electrode intermediate layer to 1:1, the negative electrode and button cell are manufactured in essentially the same manner as in Example 1.

[0134] Example 8: Cu substrate / negative electrode intermediate layer (AgNP+C, 2:1) / protective layer (PVDF+PEO, 9:1) Except for changing the weight ratio of Ag nanoparticles to carbon black included in the negative electrode intermediate layer to 2:1, the negative electrode and button cell are manufactured in essentially the same manner as in Example 1.

[0135] Comparison Example 1: Cu substrate / protective layer (PVDF+PEO, 9:1) Except for not applying the negative electrode intermediate layer, the negative electrode and the button cell are manufactured in essentially the same manner as in Example 1.

[0136] Comparison Example 2: Cu substrate / first negative electrode intermediate layer (AgNP) / second negative electrode intermediate layer (C) / protective layer (PVDF+PEO, 9:1) The negative electrode and the coin cell are manufactured in essentially the same manner as in Example 1, except that instead of introducing a 3:1 mixture of Ag nanoparticles and carbon black onto the negative electrode current collector, a first negative electrode interlayer containing Ag nanoparticles and a second negative electrode interlayer containing carbon black are applied.

[0137] Comparative Example 3: Cu substrate / negative electrode intermediate layer (AgNP) / protective layer (PVDF+PEO, 9:1) The negative electrode and the coin cell are manufactured in essentially the same manner as in Example 1, except that the negative electrode intermediate layer consists only of Ag nanoparticles and does not contain carbon black.

[0138] Comparative Example 4: Cu substrate / negative electrode intermediate layer (AgNP+C, 1:3) / protective layer (separate PVDF) Except that the protective layer contains only PVDF, the negative electrode and the coin cell are manufactured in essentially the same manner as in Example 1.

[0139] Evaluation Example 1: Charge / Discharge Test The lithium batteries prepared in Examples 1 to 8 and Comparative Examples 1 to 4 were tested at 25°C at a rate of 1.0 mAh / cm². 2 A constant current of 0.5 mA / cm 2 Charged at a current density of 0.1 mA / cm². 2 A constant current is used to discharge until the voltage reaches 1.0V (relative to Li).

[0140] Repeat the cycle under the same conditions until the 10th cycle.

[0141] A 10-minute stop time is provided after each charge / discharge cycle in all charge / discharge cycles. The results of Example 1 and Comparative Example 1 are shown in the table below, from the results of room temperature charge and discharge tests. Figure 7 and Figure 8 Furthermore, the results of Examples 1 to 8 and Comparative Examples 1 to 4 are shown in Table 1 below. The charge / discharge efficiency is defined by Equation 1 below.

[0142] The charge / discharge efficiency and overpotential values ​​after the 10th cycle are shown in Table 1 below.

[0143] Equation 1 Charge / discharge efficiency [%] = [Discharge capacity in the Nth cycle / Charge capacity in the Nth cycle] × 100 Table 1

[0144] like Figure 7 and Figure 8 As shown in Table 1, compared with the lithium batteries of Comparative Examples 1 to 4, the lithium batteries of Examples 1 to 8 have improved charging / discharging efficiency and reduced overpotential values.

[0145] These improved lifetime characteristics and overpotential reduction effects of the lithium batteries in Examples 1 to 8 can be achieved by suppressing or reducing side reactions caused by solvent decomposition on the negative electrode surface and by suppressing or reducing local current density imbalances caused by the bilayer structure, which includes: a negative electrode interlayer containing AgNP and carbon black; and a protective layer containing PVDF and PEO.

[0146] In the lithium batteries of Comparative Examples 1 to 4, it can be seen that the protective layer and the negative electrode intermediate layer cannot effectively suppress or reduce side reactions with the solvent and / or local current density imbalance.

[0147] Exemplary embodiments have been described in more detail with reference to the accompanying drawings, but this disclosure is not limited to these examples. It should be apparent to those skilled in the art to which this disclosure pertains that various examples of changes or modifications can be derived within the scope of the technical concept described in the appended claims, and all such examples are within the technical scope of this disclosure.

[0148] List of reference numerals for key components 1. Lithium battery 2. 20 negative electrode 3. 10 positive electrode 4 separator 5 Battery casings 6 Cover components 7 Battery structure 8 Electrode terminals 11 Positive current collector 12 Positive active material layer 21 Negative electrode current collector 22 Negative electrode intermediate layer 23 Metal layer 24 Protective layer 30 Solid electrode layer.

Claims

1. A negative electrode, said negative electrode comprising: Negative electrode current collector; A protective layer is located on one surface of the negative electrode current collector; as well as The negative electrode intermediate layer is located between the negative electrode current collector and the protective layer. Wherein: the protective layer comprises a first polymer and a second polymer, wherein the first polymer comprises a high-strength polymer, and the second polymer comprises an ion-conducting polymer, and The negative electrode intermediate layer includes a mixture comprising a first particle and a second particle, wherein the first particle comprises a lithium-philic metal and the second particle comprises carbon.

2. The negative electrode according to claim 1, wherein: The lithiophilic metals include gold (Au), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi), tin (Sn), magnesium (Mg), zinc (Zn), or combinations thereof.

3. The negative electrode according to claim 1, wherein: The second particle comprises amorphous carbon, crystalline carbon, or a combination thereof.

4. The negative electrode according to claim 1, wherein: The ratio of the first particle to the second particle is 5:1 to 1:

5.

5. The negative electrode according to claim 1, wherein: The negative electrode intermediate layer also includes a binder.

6. The negative electrode according to claim 1, wherein: The thickness of the negative electrode intermediate layer is 0.1 μm to 5 μm.

7. The negative electrode according to claim 1, wherein: The high-strength polymer has a higher elastic modulus than the second polymer.

8. The negative electrode according to claim 1, wherein: The high-strength polymers include fluoropolymers.

9. The negative electrode according to claim 8, wherein: The fluoropolymers include polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), vinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP), polyvinylidene fluoride (PVF), or combinations thereof.

10. The negative electrode according to claim 1, wherein: The ion-conducting polymers include polyethylene oxide (PEO), polyethylene glycol (PEG), polyacrylonitrile (PAN), polyethylene dioxythiophene (PEDOT), polypyrrole (PPY), polyacrylonitrile (PAN), polyaniline, polyacetylene, or combinations thereof.

11. The negative electrode according to claim 1, wherein: The amount of the first polymer is greater than or equal to the amount of the second polymer.

12. The negative electrode according to claim 1, wherein: The protective layer is lithium salt-free and non-porous.

13. The negative electrode according to claim 1, wherein: The thickness of the protective layer is 100 nm to 20 μm.

14. The negative electrode according to claim 1, wherein: The thickness ratio of the negative electrode intermediate layer to the protective layer is 1:1 to 1:

20.

15. The negative electrode according to claim 1, wherein: The negative electrode current collector includes indium (In), copper (Cu), magnesium (Mg), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), aluminum (Al), germanium (Ge), tin (Sn), lithium (Li), or their alloys or conjugates.

16. The negative electrode according to claim 1, wherein: The negative electrode current collector includes a substrate membrane and a metal layer on one or opposite surfaces of the substrate membrane. The substrate film comprises a polymer, and the polymer comprises polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP), polybutylene terephthalate (PBT), polyimide (PI), or combinations thereof. The metal layer includes indium (In), copper (Cu), magnesium (Mg), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), aluminum (Al), germanium (Ge), tin (Sn), lithium (Li), or alloys or conjugates thereof.

17. The negative electrode according to claim 1, further comprising: A metal layer is located between the negative electrode current collector and the negative electrode intermediate layer.

18. The negative electrode according to claim 17, wherein: The metal layer contains no adhesive.

19. A lithium battery, said lithium battery comprising: positive electrode; The negative electrode according to claim 1; as well as Electrolyte, located between the positive electrode and the negative electrode.

20. The lithium battery according to claim 19, wherein: The electrolyte is a liquid electrolyte, a solid electrolyte, a gel electrolyte, or a combination thereof.

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