Negative electrode, lithium battery comprising same, and method for manufacturing negative electrode

Abstract

Provided are an anode electrode including: an anode current collector; and an anode active material layer on one surface of the anode current collector, a lithium battery including same, and a manufacturing method therefor, wherein the anode active material layer includes a porous structure, the porous structure includes a first anode active material, the first anode active material includes an organic anode active material, and the organic anode active material includes a polyimide-based polymer.

Description

Anode, lithium battery including the same, and method for manufacturing the anode

[0001] It relates to a cathode, a lithium battery including the same, and a method for manufacturing the cathode.

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

[0003] Lithium metal can be used as an anode material. The theoretical electrical capacity of lithium metal is 3860 mAh / g. However, lithium metal side reactions with the electrolyte during charge and discharge can degrade the lifespan of lithium batteries.

[0004] In a lithium metal battery, a lithium metal layer is placed between the electrolyte and the negative electrode current collector. By omitting the lithium metal layer during lithium battery assembly, the energy density per unit weight of the lithium battery can be improved.

[0005] In a non-anode lithium battery, the lithium metal layer is omitted during lithium battery assembly. By omitting the anode active material layer in the lithium battery, the energy density of the lithium battery is improved.

[0006] When a non-anode lithium battery is charged and discharged, a lithium metal layer is deposited between the electrolyte layer and the negative electrode current collector, and the deposited lithium metal layer is dissolved. As the non-anode lithium battery is repeatedly charged and discharged, the rapid volume change of the lithium metal layer causes the formation of lithium dendrites. The lithium dendrites continuously grow during the charge and discharge process, causing a short circuit between the positive and negative electrodes. Consequently, the lithium battery deteriorates. Therefore, an anode is required that can suppress the rapid volume change of the lithium metal layer during the charge and discharge process of a lithium battery, enable the deposition of a dense lithium metal layer, and maintain a uniform lithium ion flow at the interface between the electrolyte layer and the negative electrode and / or within the negative electrode.

[0007] One aspect is to provide a negative electrode in which volume change of a lithium battery is suppressed during charge and discharge by including a novel porous structure.

[0008] Another aspect is to provide a lithium battery having improved cycle characteristics by having a new cathode.

[0009] According to the implementation example

[0010] A negative electrode current collector; and a negative electrode active material layer on one surface of the negative electrode current collector,

[0011] The above negative electrode active material layer includes a porous structure,

[0012] The above porous structure includes a first negative electrode active material,

[0013] The above first negative electrode active material includes an organic negative electrode active material,

[0014] A negative electrode is provided, wherein the organic negative electrode active material includes a polyimide-based polymer.

[0015] According to the implementation example

[0016] A negative electrode current collector; and a porous negative electrode active material layer on one surface of the negative electrode current collector,

[0017] The above porous negative electrode active material layer includes a porous structure,

[0018] A cathode is provided, wherein the porous structure includes a polyimide-based polymer.

[0019] According to another implementation example,

[0020] A cathode comprising a cathode current collector; and a cathode active material layer on one surface of the cathode current collector;

[0021] The cathode according to the above; and

[0022] A lithium battery is provided, including an electrolyte layer disposed between the positive electrode and the negative electrode.

[0023] According to another implementation example,

[0024] A step of providing a negative electrode collector;

[0025] A step of preparing a laminate including a porous precursor structure by electrospinning a solution including a polyimide-based polymer precursor on the negative electrode current collector; and

[0026] A method for manufacturing a cathode is provided, including a step of heat-treating the laminate to prepare a cathode including a polyamide-based polymer porous structure.

[0027] According to one aspect, it is possible to provide a negative electrode in which volume change is suppressed during charge and discharge by having a porous structure capable of associating and dissociating lithium ions.

[0028] According to another aspect, it is possible to provide a lithium battery having improved cycle characteristics by having the above-described negative electrode.

[0029] Figure 1 is a cross-sectional schematic diagram of a lithium battery according to an exemplary embodiment.

[0030] Figure 2 is a cross-sectional schematic diagram of a lithium battery according to an exemplary embodiment.

[0031] Figure 3 is a scanning electron microscope image of the cathode surface of Example 1.

[0032] Figure 4 shows the results of a cyclic current low-voltage method measurement of a lithium battery including the negative electrode of Example 1.

[0033] Figure 5 shows the results of cyclic voltammetry measurements of a lithium battery including the negative electrode of Comparative Example 1.

[0034] Figure 6 is a schematic diagram of a lithium battery according to an exemplary embodiment.

[0035] Figure 7 is a schematic diagram of a lithium battery according to an exemplary embodiment.

[0036] Figure 8 is a schematic diagram of a lithium battery according to an exemplary embodiment.

[0037] Figure 9 is a schematic diagram of a lithium battery according to an exemplary embodiment.

[0038] Unless otherwise defined, all terms (including technical and scientific terms) used in this disclosure have the same meaning as commonly understood by those of ordinary skill in the art to which this disclosure pertains. Furthermore, terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning within the context of the relevant technology and this disclosure, and should not be interpreted in an idealized or overly formal sense.

[0039] Exemplary embodiments are described in this disclosure with reference to cross-sectional drawings that are schematic representations of idealized embodiments. As such, variations from the shapes depicted are to be expected, for example, as a result of manufacturing techniques and / or tolerances. Therefore, the embodiments described in this disclosure should not be construed as limited to the specific shapes of regions as depicted in this disclosure, but should encompass variations in shapes resulting from, for example, manufacturing. For example, regions depicted or described as flat may typically have rough and / or non-linear features. Moreover, angles depicted as sharp may be rounded. Therefore, the regions depicted in the drawings are schematic in nature, and their shapes are not intended to depict the precise shapes of the regions, nor are they intended to limit the scope of the claims.

[0040] This creative idea may be embodied in many different forms and should not be construed as limited to the embodiments described in this disclosure. These embodiments are provided so that this disclosure will be thorough and complete, and so that it will fully convey the scope of the creative idea to those skilled in the art. Like reference numerals in the drawings indicate like elements.

[0041] When a component is referred to as being "on" another component, it can be understood that it is either directly on top of the other component or that other components may be intervening between them. Conversely, when a component is referred to as being "directly on" another component, no intervening components are present.

[0042] Although terms such as "first," "second," "third," etc. may be used herein to describe various components, elements, regions, layers, and / or zones, these components, elements, regions, layers, and / or zones should not be limited by these terms. These terms are only used to distinguish one component, element, region, layer, or zone from another component, element, region, layer, or zone. Thus, a first component, element, region, layer, or zone described below may be referred to as a second component, element, region, layer, or zone without departing from the teachings of this disclosure.

[0043] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms including "at least one," unless the content clearly dictates otherwise. "At least one" should not be construed as limiting to the singular. As used herein, the term "and / or" includes any and all combinations of one or more of the listed items. The terms "comprises" and / or "comprising" as used in the detailed description specify the presence of stated features, regions, integers, steps, operations, components, and / or ingredients, but do not preclude the presence or addition of one or more other features, regions, integers, steps, operations, components, ingredients, and / or groups thereof.

[0044] Spatially relative terms such as "below," "under," "lower," "above," "upper," and the like may be used herein to readily describe the relationship of one component or feature to another. It will be understood that spatially relative terms are intended to encompass different orientations of the device when in use or operation in addition to the orientations depicted in the drawings. For example, if the device in the drawings were turned over, a component described as "below" or "below" another component or feature would then be oriented "above" the other component or feature. Thus, the exemplary term "below" can encompass both the above and below orientations. The device may be arranged in other orientations (rotated 90 degrees or otherwise rotated), and the spatially relative terms used herein may be interpreted accordingly.

[0045] "Group" means a group in the periodic table of elements according to the International Union of Pure and Applied Chemistry ("IUPAC") Group 1-18 classification system.

[0046] In this disclosure, “particle diameter” refers to the average diameter when the particle is spherical, and refers to the average major axis length when the particle is non-spherical. The particle diameter can be measured using a particle size analyzer (PSA). The “particle diameter” is, for example, the average particle diameter. The “average particle diameter” is, for example, D50, the median particle diameter.

[0047] D50 is the size of the particle corresponding to 50% of the cumulative volume, calculated from the particle side with a smaller particle size in the particle size distribution measured by laser diffraction.

[0048] D90 is the size of the particle corresponding to 90% of the cumulative volume, calculated from the particle side with a smaller particle size in the particle size distribution measured by laser diffraction.

[0049] D10 is the size of the particle corresponding to 10% of the cumulative volume, calculated from the particle side with a small particle size in the particle size distribution measured by laser diffraction.

[0050] In this disclosure, “metal” includes both metals and metalloids such as silicon and germanium, in their elemental or ionic states.

[0051] In this disclosure, “alloy” means a mixture of two or more metals.

[0052] In the present disclosure, “electrode active material” means an electrode material capable of undergoing lithiation and delithiation.

[0053] In the present disclosure, “positive electrode material” means a positive electrode material capable of undergoing lithiation and delithiation.

[0054] In the present disclosure, “negative electrode active material” means a negative electrode material capable of undergoing lithiation and delithiation.

[0055] In the present disclosure, “lithiation” and “lithiating” mean a process of adding lithium to an electrode active material.

[0056] In the present disclosure, “delithiation” and “delithiate” mean a process of removing lithium from an electrode active material.

[0057] In this disclosure, “charging” and “charging” mean a process of providing electrochemical energy to a battery.

[0058] In this disclosure, “discharging” and “discharging” mean the process of removing electrochemical energy from a battery.

[0059] In the present disclosure, “positive electrode” and “cathode” mean an electrode at which electrochemical reduction and lithiation occur during a discharge process.

[0060] In the present disclosure, “cathode” and “anode” mean electrodes where electrochemical oxidation and delithiation occur during a discharge process.

[0061] While specific implementations have been described, alternatives, modifications, variations, improvements, and substantial equivalents that are not currently anticipated or unforeseen may occur to the applicant or those skilled in the art. Accordingly, the appended claims, as filed and as amended, are intended to encompass all such alternatives, modifications, variations, improvements, and substantial equivalents.

[0062] Below, a negative electrode and a lithium battery including the same according to exemplary embodiments are described in more detail.

[0063] [Lithium battery]

[0064] According to one embodiment, a negative electrode includes a negative current collector; and a negative active material layer on one surface of the negative current collector. The negative active material layer includes a porous structure. The porous structure includes a first negative active material. The first negative active material includes an organic negative active material. The organic negative active material includes a polyimide-based polymer. The negative active material layer is, for example, a porous negative active material layer.

[0065] Since the anode includes a porous anode active material layer, lithium metal precipitates into the pores of the porous anode active material layer during charge and discharge, thereby suppressing volume changes in the anode and lithium battery. This suppresses the precipitation of lithium dendrites caused by rapid volume changes in the lithium metal layer during charge and discharge. Consequently, the cycle characteristics of the lithium battery are improved.

[0066] By including a porous structure in the negative electrode active material layer, dense lithium precipitation is enabled within the negative electrode active material layer. This ensures uniform lithium ion flow at the interface between the electrolyte layer and the negative electrode active material layer, the interface between the negative electrode active material layer and the negative electrode current collector, and / or within the negative electrode active material layer. Consequently, rapid volume changes in the negative electrode active material layer can be suppressed and the formation of lithium dendrites can be suppressed. Consequently, the cycle characteristics of the lithium battery are improved.

[0067] The porous structure includes an organic negative electrode active material as a first negative electrode active material. The organic negative electrode active material can form an ionic compound by associating and / or dissociating with lithium ions. Therefore, the affinity of the porous structure for lithium ions is increased. In addition, the reversibility of the electrode reaction during charge and discharge of the negative electrode including the porous structure is improved. Consequently, the irreversible capacity during the initial charge and discharge of a lithium battery can be reduced. The decrease in Coulombic efficiency during charge and discharge of a lithium battery can be suppressed.

[0068] By including a polyimide-based polymer in the organic anode active material, improved thermal stability can be achieved. Furthermore, by including a polyimide-based polymer in the organic anode active material, the use of a separate, additional binder in the anode active material layer can be omitted. Consequently, the cycle characteristics of lithium batteries can be improved. For example, the high-temperature cycle characteristics of lithium batteries can be enhanced.

[0069] Figures 1 and 2 are cross-sectional schematic diagrams of a lithium battery according to an embodiment.

[0070] Referring to FIGS. 1 and 2, a lithium battery (1) includes a negative electrode (20). The negative electrode (20) includes a negative electrode current collector (21); and a porous negative electrode active material layer (22) on one surface of the negative electrode current collector (21).

[0071] [cathode]

[0072] [Cathode: Cathode active material layer]

[0073] Referring to Fig. 1, the negative electrode active material layer (22) is porous. The negative electrode active material layer (22) is porous, for example, when assembling a battery. Since the negative electrode active material layer (22) is porous, the volume change of the negative electrode active material layer (22) during charge and discharge can be suppressed. The volume change of the lithium battery (1) including the negative electrode active material layer (22) can be suppressed during charge and discharge. As a result, the cycle characteristics of the lithium battery (1) are improved.

[0074] Referring to FIGS. 1 and 3, the negative electrode active material layer (22) includes a porous structure (23). The porous structure (23) includes a first negative electrode active material. The first negative electrode active material includes an organic negative electrode active material. The organic negative electrode active material is, for example, a negative electrode active material made of an organic material. The organic negative electrode active material can form an ionic compound, for example, by associating and / or dissociating with lithium ions. The ionic compound is, for example, an ionic compound, a salt, or a complex. The organic negative electrode active material can provide charge / discharge capacity by associating and dissociating with lithium ions during charge / discharge. The organic negative electrode active material is, for example, a polymer negative electrode active material. The organic negative electrode active material includes, for example, a polyimide-based polymer.

[0075] Referring to FIGS. 1 and 3, the porous structure (23) may be, for example, a porous three-dimensional structure. Since the porous structure (23) is a three-dimensional structure, the contact area with lithium ions is increased and structural stability can be provided. The porous structure (23) includes, for example, a fibrous polymer or a polymer fiber. Since the porous structure (23) includes a fibrous polymer, the structural stability of the porous structure (23) can be improved. The aspect ratio of the fibrous polymer is, for example, 5 or more, 10 or more, 20 or more, 50 or more, or 100 or more. The aspect ratio of the fibrous polymer is, for example, 5 to 1000, 10 to 1000, 20 to 1000, 50 to 1000, or 100 to 1000. The cycle characteristics of a lithium battery including a porous structure (23) can be further improved by having an aspect ratio of the fibrous polymer in this range. The aspect ratio of the fibrous polymer can be measured from a scanning electron microscope or transmission electron microscope image of the porous structure (23).

[0076] Referring to FIGS. 1 and 3, the diameter of the fibrous polymer may have, for example, a diameter of 10 nm to 500 μm, 20 nm to 100 μm, 40 nm to 50 μm, 60 nm to 10 μm, 100 nm to 5 μm, 100 nm to 3 μm, or 100 nm to 1 μm. When the fibrous polymer has a diameter in this range, the cycle characteristics of a lithium battery including the porous structure (23) can be further improved. The diameter of the fibrous polymer can be measured from a scanning electron microscope or transmission electron microscope image of the porous structure (23).

[0077] Referring to FIGS. 1 and 3, the porous structure (23) may have a three-dimensional network structure including, for example, a plurality of interconnected fibrous polymers. The three-dimensional network structure may be formed by the plurality of interconnected fibrous polymers intersecting each other. Since the porous structure (23) has a three-dimensional network structure, the transfer path of lithium ions may be reduced through the three-dimensional network structure of the porous structure (23). The reversibility of the electrode reaction may be improved. As a result, the cycle characteristics of a lithium battery including the porous structure (23) may be improved.

[0078] Referring to FIGS. 1 and 3, the porous structure (23) may include, for example, a plurality of fibrous polymers that are arranged irregularly or non-periodically. By including a plurality of fibrous polymers that are arranged irregularly or non-periodically, the porous structure (23) may have isotropy. The porous structure (23) may easily accommodate changes in the volume of the porous structure (23) due to lithium precipitating regardless of direction.

[0079] Referring to FIGS. 1 and 3, the porosity of the porous structure (23) may be, for example, 10 to 90%, 20 to 90%, 30 to 90%, 40 to 90%, 50 to 90%, 60 to 90%, or 60 to 80%. Since the porous structure (23) has a porosity in this range, it can more easily accommodate the change in volume of the negative electrode active material layer during charge and discharge. It can more easily accommodate the lithium metal precipitated during charge and discharge of the lithium battery. As a result, the cycle characteristics of the lithium battery are improved. If the porosity is too low, it may be difficult to easily accommodate the change in volume of the negative electrode active material layer during charge and discharge. If the porosity is too high, the structural stability may be deteriorated. The porosity of the porous structure (23) can be calculated, for example, by the pore area measured in a scanning electron microscope image. The porosity of the porous structure (23) can be measured, for example, by a gas adsorption method.

[0080] Referring to FIGS. 1 and 3, the porous structure (23) may include, for example, a plurality of pores (24) that are irregularly or non-periodically arranged within the porous structure (23). By including a plurality of pores (24) that are irregularly or non-periodically arranged within the porous structure (23), various forms of precipitated lithium can be easily accommodated within the porous structure (23).

[0081] Referring to FIGS. 1 and 3, the size of the pores (24) in the porous structure (23) may be, for example, 10 nm to 10 ㎛, 50 nm to 10 ㎛, 100 nm to 10 ㎛, 100 nm to 8 ㎛, 100 nm to 7 ㎛, or 100 nm to 5 ㎛. The size of the pores (24) may be, for example, determined by a gas adsorption method or a mercury intrusion porosimeter. The size of the pores (24) is the diameter of the pores in spherical pores, and the maximum distance between the two ends of the pores in non-spherical pores. The size of the pores (24) may be, for example, the diameter of the pores (24). The diameter of the pores (24) may be, for example, the average diameter of the pores (24). The average diameter of the pores (24) may be, for example, the median diameter of the pores (24), i.e., the D50 diameter. The D50 diameter of the pores (24) may be determined from a pore size distribution measured by, for example, nitrogen adsorption or mercury porosimetry.

[0082] Referring to FIGS. 1 and 3, the porous structure (23) may be, for example, a polymer porous structure (23). The polymer porous structure (23) may be, for example, a polymeric porous film or a polymeric porous web. The polymeric porous structure (23) may be, for example, a porous film or a porous web in which a plurality of fibrous polymers are three-dimensionally connected. The polymeric porous structure (23) may be, for example, in the form of a sheet. The thickness of the porous structure (23) may be, for example, 1 to 200 μm, 1 to 100 μm, 5 to 100 μm, 10 to 100 μm, or 50 to 100 μm. When the thickness of the porous structure (23) is in this range, the cycle characteristics of a lithium battery including the porous structure (23) can be further improved. If the thickness of the porous structure (23) is too small, it may be difficult to easily accommodate the precipitated lithium metal. If the thickness of the porous structure (23) is too thick, the energy density per unit volume of the lithium battery may decrease.

[0083] Referring to FIGS. 1 to 3, the negative electrode active material layer (22) includes a porous structure (23), and the thickness of the negative electrode active material layer (22) may be, for example, 1 to 200 ㎛, 1 to 100 ㎛, 5 to 100 ㎛, or 10 to 100 ㎛. When the thickness of the negative electrode active material layer (22) has this range, the cycle characteristics of a lithium battery including the negative electrode active material layer (22) can be further improved. If the thickness of the negative electrode active material layer (22) is too small, it may be difficult to easily accommodate the precipitated lithium metal. If the thickness of the negative electrode active material layer (22) is too thick, the energy density per unit volume of the lithium battery may be reduced.

[0084] Polyimide polymers include, for example, imide repeating units. Polyimide polymers include, for example, polyimide, polyamideimide, polyetherimide, or combinations thereof. The molecular weight of the polyimide polymer is, for example, 1,000 to 5,000,000 Daltons, 10,000 to 3,000,000 Daltons, 100,000 to 2,000,000 Daltons, or 500,000 to 1,500,000 Daltons. The molecular weight of the polyimide polymer can be measured, for example, using GPC (Gel Permeation Chromatography) on a polystyrene standard sample.

[0085] The polyimide polymer may be, for example, a polymer represented by the following chemical formulas 1 to 3:

[0086] <Chemical Formula 1>

[0087]

[0088] <Chemical Formula 2>

[0089]

[0090] <Chemical Formula 3>

[0091]

[0092] In the above formulas,

[0093] Ar1 is an aromatic ring group selected from a substituted or unsubstituted tetravalent arylene group having 6 to 24 carbon atoms or a substituted or unsubstituted tetravalent heteroarylene group having 4 to 24 carbon atoms,

[0094] The above aromatic ring group is one aromatic ring, a ring in which two or more aromatic rings are fused, or two or more aromatic rings are single bonded, -O-, -S-, -C(=O)-, -S(=O)2-, -Si(R a )(R b )-(R a and R bare independently an alkyl group having 1 to 10 carbon atoms), an alkylene group having 1 to 10 carbon atoms substituted or unsubstituted with halogen, or a ring connected by -C(=O)-NH-O,

[0095] Ar3, Ar5 and Ar6 are independently an aromatic ring group selected from among a substituted or unsubstituted trivalent arylene group having 6 to 24 carbon atoms or a substituted or unsubstituted trivalent heteroarylene group having 4 to 24 carbon atoms,

[0096] The above aromatic ring group is one aromatic ring, a ring in which two or more aromatic rings are fused, or two or more aromatic rings are single bonded, -O-, -S-, -C(=O)-, -S(=O)2-, -Si(R a )(R b )-(R a and R b are independently an alkyl group having 1 to 10 carbon atoms), an alkylene group having 1 to 10 carbon atoms substituted or unsubstituted with halogen, or a ring connected by -C(=O)-NH-O,

[0097] Ar2, Ar4, Ar7 and Ar8 are independently an aromatic ring group selected from a substituted or unsubstituted divalent arylene group having 6 to 24 carbon atoms or a substituted or unsubstituted divalent heteroarylene group having 4 to 24 carbon atoms,

[0098] The above aromatic ring group is one aromatic ring, a ring in which two or more aromatic rings are fused, or two or more aromatic rings are single bonded, -O-, -S-, -C(=O)-, -S(=O)2-, -Si(R a )(R b )-(R a and R b are independently an alkyl group having 1 to 10 carbon atoms), an alkylene group having 1 to 10 carbon atoms substituted or unsubstituted with halogen, or a ring connected by -C(=O)-NH-,

[0099] X1, X2, X3, X4, X5, X6, X7 and X8 are independently a single bond, -O-, -S-, -C(=O)-, -S(=O)2-, -Si(R a )(R b )-(R a and R b are independently an alkyl group having 1 to 10 carbon atoms), an alkylene group having 1 to 10 carbon atoms substituted or unsubstituted with halogen, or a ring connected by -C(=O)-NH-,

[0100] n is between 2 and 20,000.

[0101] The polyimide polymer may be, for example, a polymer represented by the following chemical formulas 4 to 10:

[0102] <Chemical Formula 4>

[0103]

[0104] <Chemical Formula 5>

[0105]

[0106] <Chemical Formula 6>

[0107]

[0108] <Chemical Formula 7>

[0109]

[0110] <Chemical Formula 8>

[0111]

[0112] <Chemical Formula 9>

[0113]

[0114] <Chemical Formula 10>

[0115]

[0116] In the above formulas,

[0117] X1, X2, X3, X4, X5, X6, X7, X8, Y1, Y2, Y3 and Y4 are independently a single bond, -O-, -S-, -C(=O)-, -S(=O)2-, -Si(R a )(R b )-(R a and R b are independently an alkyl group having 1 to 10 carbon atoms), an alkylene group having 1 to 10 carbon atoms substituted or unsubstituted with halogen, or a ring connected by -C(=O)-NH-,

[0118] n is between 100 and 20,000.

[0119] The negative electrode active material layer (22) may not include a binder, for example. The negative electrode active material layer (22) may be, for example, binder-free. Since the negative electrode active material layer (22) includes a polymer porous structure (23), it may not additionally include a separate binder. Since the negative electrode active material layer (22) does not include a separate binder, the internal resistance of the negative electrode active material layer (22) may be reduced. The cycle characteristics of a lithium battery (1) including the negative electrode active material layer (22) may be improved.

[0120] The negative electrode active material layer (22) may further include, for example, a conductive material. The porous structure (23) may further include, for example, a conductive material. The porous structure (23) may include a fibrous polymer, and the conductive material may be disposed on the surface and / or inside the fibrous polymer. The conductive material may include, for example, a carbon-based conductive material, a metal-based conductive material, or a combination thereof. The carbon-based conductive material may include, for example, carbon black, acetylene black, furnace black, ketjen black, graphene, graphene oxide, reduced graphene oxide, carbon fiber, carbon nanotubes (CNT), or a combination thereof. The carbon-based conductive material may include, for example, a doped carbon-based conductive material. The doped carbon-based conductive material may include a dopant. The dopant may include, for example, nitrogen (N), sulfur (S), fluorine (F), chlorine (Cl), or a combination thereof. The doped carbon-based conductive material may include, for example, nitrogen-doped graphene, nitrogen-doped graphene oxide, nitrogen-doped reduced graphene oxide, nitrogen-doped carbon fibers, nitrogen-doped carbon nanotubes (CNTs), or a combination thereof. The doped carbon-based conductive material may include, for example, fluorine-doped graphene, fluorine-doped graphene oxide, fluorine-doped reduced graphene oxide, fluorine-doped carbon fibers, fluorine-doped carbon nanotubes (CNTs), or a combination thereof. The doped carbon-based conductive material may include, for example, sulfur-doped graphene, sulfur-doped graphene oxide, sulfur-doped reduced graphene oxide, sulfur-doped carbon fibers, sulfur-doped carbon nanotubes (CNTs), or a combination thereof. The metal-based conductive material may be, for example, metal powder, metal fiber, or a combination thereof, but is not limited thereto, and any material used as a metal-based conductive material in the relevant technical field may be used.

[0121] The conductive material content may be, for example, 0.01 to 5 wt%, 0.05 to 5 wt%, 0.1 to 5 wt%, 0.1 to 3 wt%, or 0.1 to 2 wt% of the total weight of the porous structure (23). When the porous structure (23) has a conductive material content in this range, the internal resistance of the negative electrode active material layer may be reduced. The cycle characteristics of the lithium battery (1) may be further improved. If the conductive material content is too low, the effect may be minimal. If the conductive material content is too high, the energy density of the lithium battery (1) may be reduced. The conductive material content may be, for example, 0.01 to 5 wt%, 0.05 to 5 wt%, 0.1 to 5 wt%, 0.1 to 3 wt%, or 0.1 to 2 wt% of the total weight of the negative electrode active material layer (22).

[0122] Referring to FIG. 2, the negative electrode active material layer may further include, for example, a second negative electrode active material (25) disposed within the pores (24) of the porous structure (23). Since the negative electrode active material layer (22) includes the porous structure (23), the second negative electrode active material (25) may be additionally disposed within the pores (24) of the porous structure (23). The second negative electrode active material (25) includes, for example, lithium metal, a lithium alloy, or a combination thereof. The second anode active material (25) is a metal containing lithium, so the first anode active material (2% 0) disposed within the pores (24) acts as, for example, a lithium reservoir. The lithium alloy is, for example, a Li-Al alloy, a Li-Sn alloy, a Li-In alloy, a Li-Ag alloy, a Li-Au alloy, a Li-Zn alloy, a Li-Ge alloy, a Li-Si alloy, etc., but is not limited thereto, and any material used as a lithium alloy in the relevant technical field is possible. The second anode active material (25) may be made of one of these alloys or lithium, or may be made of several types of alloys. The second anode active material (25) is, for example, a plated anode active material. The second anode active material (25) may be deposited within the pores (24) of the anode active material layer (22), that is, within the pores (24) of the porous structure (23), for example, during the charging process of the lithium battery (1).

[0123] [Cathode: Negative current collector]

[0124] The negative electrode current collector (21) is composed of, for example, a material that does not react with lithium, i.e., does not form an alloy or a compound. The material constituting the negative electrode current collector (21) is, for example, copper, nickel, nickel-coated copper, stainless steel (SUS), iron (Fe), cobalt (Co), etc., but is not necessarily limited thereto, and any material that is used as an electrode current collector in the relevant technical field may be used. The negative electrode current collector (21) may be composed of one type of the above-described metal, or may be composed of an alloy or a coating material of two or more types of metals. The negative electrode current collector (21) is, for example, in the form of a plate or foil.

[0125] The negative electrode current collector (21) is not shown in the drawing, but may include, for example, a base film and a metal layer disposed on one or both sides of the base film. The base 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), or a combination thereof. Since the base film includes a thermoplastic polymer, the base film may melt when a short circuit occurs, thereby suppressing a rapid increase in current. The base film may be, for example, an insulator. The metal layer may include, for example, indium (In), copper (Cu), magnesium (Mg), titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), aluminum (Al), germanium (Ge), lithium (Li), or an alloy thereof. In particular, the metal layer may include, for example, copper (Cu), titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), or an alloy thereof. The metal layer may act as an electrochemical fuse and may be cut off in the event of an overcurrent to prevent a short circuit. The limit current and the maximum current may be controlled by adjusting the thickness of the metal layer. The metal layer may be plated or deposited on the base film. As the thickness of the metal layer decreases, the limit current and / or the maximum current of the negative electrode current collector (21) decrease, thereby improving the stability of the lithium battery in the event of a short circuit. A lead tab may be added on the metal layer for connection to the outside. The lead tab may be welded to the metal layer or the metal layer / base film laminate by ultrasonic welding, laser welding, spot welding, or the like. When welding, the base film and / or the metal layer may be melted, so that the metal layer may be electrically connected to the lead tab.In order to make the welding between the metal layer and the lead tab more robust, a metal chip may be added between the metal layer and the lead tab. The metal chip may be a thin piece of the same material as the metal of the metal layer. The metal chip may be, for example, a metal foil, a metal mesh, etc. The metal chip may be, for example, copper foil, nickel foil, etc. By placing the metal chip on the metal layer and then welding it with the lead tab, the lead tab may be welded to the metal chip / metal layer laminate or the metal chip / metal layer / base film laminate. During welding, the base film, the metal layer, and / or the metal chip may melt, so that the metal layer or the metal layer / metal chip laminate may be electrically connected to the lead tab. The metal chip and / or the lead tab may be added to a portion of the metal layer. The thickness of the base film may be, for example, 1 to 50 ㎛, 1.5 to 50 ㎛, 1.5 to 40 ㎛, or 1 to 30 ㎛. By having a thickness of the base film in this range, the weight of the electrode assembly can be more effectively reduced. The melting point of the base film can be, for example, 100 to 300°C, 100 to 250°C, or 100 to 200°C. By having a melting point in this range, the base film can be melted and easily bonded to the lead tab during the process of welding the lead tab. A surface treatment, such as corona treatment, can be performed on the base film to improve the adhesion between the base film and the metal layer. The thickness of the metal layer can be, for example, 0.01 to 3 μm, 0.1 to 3 μm, 0.1 to 2 μm, or 0.1 to 1 μm. By having a thickness of the metal layer in this range, conductivity can be maintained while ensuring the stability of the electrode assembly. The thickness of the metal piece can be, for example, 2 to 10 μm, 2 to 7 μm, or 4 to 6 μm. By having the metal piece in this range of thickness, the connection between the metal layer and the lead tab can be performed more easily.By having this structure, the negative electrode current collector (21) can reduce the weight of the negative electrode and consequently improve the energy density of the all-solid-state secondary battery.

[0126] The negative electrode current collector (21) may further include, for example, a thin film including an element capable of forming an alloy with lithium on one surface of the negative electrode current collector (21), although not shown in the drawing. The thin film is disposed between the negative electrode current collector (21) and the negative electrode active material layer (22). The thin film includes, for example, an element capable of forming an alloy with lithium. The element capable of forming an alloy with lithium includes, but is not limited to, gold, silver, zinc, tin, indium, silicon, aluminum, bismuth, etc., and any element capable of forming an alloy with lithium in the art may be used. The thin film may be composed of one of these metals or an alloy of several types of metals. By placing the thin film on one side of the negative electrode current collector (21), the deposition form of the second negative electrode active material (25) deposited between the thin film (24) and the negative electrode active material layer (22), for example, becomes flatter, and the cycle characteristics of the lithium battery (1) can be further improved.

[0127] The thickness of the thin film is, for example, 1 nm to 800 nm, 10 nm to 700 nm, 50 nm to 600 nm, or 100 nm to 500 nm. If the thickness of the thin film is less than 1 nm, it may be difficult for the function of the thin film to be exerted. If the thickness of the thin film is excessively thick, the thin film itself absorbs lithium, thereby reducing the amount of lithium precipitation from the negative electrode (20), and the cycle characteristics of the lithium battery (1) may deteriorate. The thin film may be disposed on the negative electrode current collector (21) by, for example, a vacuum deposition method, a sputtering method, a plating method, or the like, but is not necessarily limited to these methods, and any method capable of forming a thin film in the relevant technical field may be used.

[0128] [Lithium battery]

[0129] Referring to FIGS. 1 and 2, a lithium battery (1) includes a positive electrode (10) including a positive electrode current collector (11); and a positive electrode active material layer (12) on one surface of the positive electrode current collector (11); the above-described negative electrode (20); and an electrolyte layer (30) disposed between the positive electrode (10) and the negative electrode (20). By having the above-described negative electrode (20), the cycle characteristics of the lithium battery (1) are improved.

[0130] [anode]

[0131] Referring to FIGS. 1 and 2, a lithium battery (1) according to one embodiment includes a positive electrode (10), and the positive electrode (10) includes a positive electrode current collector (11) and a positive electrode active material layer (12) disposed on one surface of the positive electrode current collector (11).

[0132] [Anode: Anode active material layer]

[0133] The cathode active material included in the cathode active material layer (12) is a cathode active material capable of reversibly absorbing and desorbing lithium ions. The cathode active material includes, for example, an oxide-based cathode active material, a sulfide-based cathode active material, or a combination thereof.

[0134] The oxide-based cathode active material includes, for example, a lithium transition metal oxide, a metal oxide, or a combination thereof. The lithium transition metal oxide includes, for example, lithium cobalt oxide, lithium nickel oxide, lithium nickel cobalt oxide, lithium nickel cobalt aluminum oxide, lithium nickel cobalt mangense oxide, lithium manganate, lithium iron phosphate, or a combination thereof. The lithium oxide includes, for example, iron oxide, vanadium oxide, or a combination thereof.

[0135] Sulfide-based cathode active materials include, for example, nickel sulfide, copper sulfide, Li2S, Li2S-containing complexes, or combinations thereof.

[0136] The oxide-based cathode active material may be, for example, at least one compound oxide of lithium and a metal selected from cobalt, manganese, nickel, and combinations thereof, and specific examples thereof include Li a A 1-b B' b D2 (in the above formula, 0.90 ≤ a ≤ 1, and 0 ≤ b ≤ 0.5); Li a E 1-b B' b O 2-c D c (In the above formula, 0.90 ≤ a ≤ 1, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05); LiE 2-b B' b O 4-c D c (In the above formula, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05); Li a Ni 1-b-c Co b B' c D α (In the above equation, 0.90 ≤ a ≤ 1, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 < α ≤ 2); Li a Ni 1-b-c Co b B' c O 2-α F' α (In the above equation, 0.90 ≤ a ≤ 1, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 < α < 2); Li a Ni 1-b-c Co b B' c O 2-α F' α (In the above equation, 0.90 ≤ a ≤ 1, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 < α < 2); Lia Ni 1-b-c Mn b B' c D α (In the above equation, 0.90 ≤ a ≤ 1, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 < α ≤ 2); Li a Ni 1-b-c Mn b B' c O 2-α F' α (In the above equation, 0.90 ≤ a ≤ 1, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 < α < 2); Li a Ni 1-b-c Mn b B' c O 2-α F' α (In the above equation, 0.90 ≤ a ≤ 1, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 < α < 2); Li a Ni b E c G d O2 (in the above formula, 0.90 ≤ a ≤ 1, 0 ≤ b ≤ 0.9, 0 ≤ c ≤ 0.5, 0.001 ≤ d ≤ 0.1); Li a Ni b Co c Mn d G e O2 (in the above formula, 0.90 ≤ a ≤ 1, 0 ≤ b ≤ 0.9, 0 ≤ c ≤ 0.5, 0 ≤ d ≤ 0.5, 0.001 ≤ e ≤ 0.1); Li a NiG b O2 (in the above formula, 0.90 ≤ a ≤ 1, 0.001 ≤ b ≤ 0.1); Li a CoG b O2 (in the above formula, 0.90 ≤ a ≤ 1, 0.001 ≤ b ≤ 0.1); Li a MnG b O2 (in the above formula, 0.90 ≤ a ≤ 1, 0.001 ≤ b ≤ 0.1); Li a Mn2G bO4 (wherein 0.90 ≤ a ≤ 1, 0.001 ≤ b ≤ 0.1); QO2; QS2; LiQS2; V2O5; LiV2O5; LiI'O2; LiNiVO4; Li (3-f) J2(PO4)3(0 ≤ f ≤ 2); Li (3-f) A compound represented by any one of the chemical formulas Fe2(PO4)3(0 ≤ f ≤ 2); LiFePO4 can be used.

[0137] In the chemical formula representing the above-described compound, 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; J is V, Cr, Mn, Co, Ni, Cu, or a combination thereof. It is also possible to use a compound having a coating layer added to the surface of the above-described compound, or it is also possible to use a mixture of the above-described compound and the compound having a coating layer added. The coating layer added to the surface of the above-mentioned compound includes a coating element compound of, for example, an oxide, a hydroxide, an oxyhydroxide of the coating element, an oxycarbonate of the coating element, or a hydroxycarbonate of the coating element of the coating element. The compound forming the coating layer is amorphous or crystalline. The coating elements included in the coating layer are Mg, Al, Co, K, Na, Ca, Si, Ti, V, Sn, Ge, Ga, B, As, Zr, or a mixture thereof. The method for forming the coating layer is selected within a range that does not adversely affect the physical properties of the positive electrode active material. The coating method includes, for example, spray coating and dipping. Since the specific coating method is well understood by those working in the relevant field, a detailed description thereof will be omitted.

[0138] The oxide-based cathode active material may include, for example, a lithium transition metal oxide represented by the following chemical formulas 11 to 18:

[0139] <Chemical Formula 11>

[0140] Li a Ni x Co y M zO 2-b A b

[0141] In the above chemical formula 11,

[0142] 1.0≤a≤1.2, 0≤b≤0.2, 0.8≤x<1, 0≤y≤0.3, 0 <z≤0.3, 및 x+y+z=1이고,

[0143] 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,

[0144] A is F, S, Cl, Br or a combination thereof,

[0145] <Chemical Formula 12>

[0146] LiNi x Co y Mn z O2

[0147] <Chemical Formula 13>

[0148] LiNi x Co y Al z O2

[0149] In the above chemical formulas 12 to 13, 0.8≤x≤0.95, 0≤y≤0.2, 0 <z≤0.2 및 x+y+z=1이며,

[0150] <Chemical Formula 14>

[0151] LiNi x Co y Mn z Al w O2

[0152] In the above chemical formula 14, 0.8≤x≤0.95, 0≤y≤0.2, 0 <z≤0.2, 0<w≤0.2, 및 x+y+z+w=1이며,

[0153] <Chemical Formula 15>

[0154] Li a Co x M y O2-b A b

[0155] In the above chemical formula 15,

[0156] 1.0≤a≤1.2, 0≤b≤0.2, 0.9≤x≤1, 0≤y≤0.1, and x+y=1,

[0157] 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,

[0158] A is F, S, Cl, Br or a combination thereof,

[0159] <Chemical Formula 16>

[0160] Li a Ni x Mn y M' z O 2-b A b

[0161] In the above chemical formula 16,

[0162] 1.0≤a≤1.2, 0≤b≤0.2, 0 <x≤0.3, 0.5≤y<1, 0<z≤0.3, 및 x+y+z=1이고,

[0163] 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,

[0164] A is F, S, Cl, Br or a combination thereof,

[0165] <Chemical Formula 17>

[0166] Li a M1 x M2 y PO 4-b X b

[0167] In the above chemical formula 17, 0.90≤a≤1.1, 0≤x≤0.9, 0≤y≤0.5, 0.9 <x+y<1.1, 0≤b≤2 이며,

[0168] M1 is chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zirconium (Zr) or a combination thereof,

[0169] 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.

[0170] <Chemical Formula 18>

[0171] Li a M3 z PO4

[0172] In the above chemical formula 18, 0.90≤a≤1.1, 0.9≤z≤1.1,

[0173] M3 is chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zirconium (Zr), or a combination thereof.

[0174] The content of the positive electrode active material included in the positive electrode active material layer (12) may be 80 wt% to 99 wt%, 90 wt% to 99 wt%, or 95 wt% to 99 wt% of the total weight of the positive electrode active material layer (12).

[0175] The cathode active material layer (12) may further include a conductive material. Examples of the conductive material include, but are not limited to, carbon black, graphite particles, natural graphite, artificial graphite, acetylene black, Ketjen black, carbon fibers; carbon nanotubes; metal powders or metal fibers or metal tubes such as copper, nickel, aluminum, and silver; and conductive polymers such as polyphenylene derivatives. Any conductive material used in the art may be used. Alternatively, the cathode may not include a separate conductive material, for example.

[0176] The conductive material content including the positive electrode active material layer (12) may be 0.1 wt% to 10 wt% or 0.1 wt% to 5 wt% of the total weight of the positive electrode active material layer (12).

[0177] The cathode active material layer (12) may further include, for example, a binder. Examples of binders that may be used include vinylidene fluoride / hexafluoropropylene copolymer, polyvinylidene fluoride, polyacrylonitrile, polymethyl methacrylate, polytetrafluoroethylene (PTFE), a mixture of the aforementioned polymers, and a styrene butadiene rubber-based polymer.

[0178] The binder content including the positive electrode active material layer (12) may be 0.1 wt% to 10 wt% or 0.1 wt% to 5 wt% of the total weight of the positive electrode active material layer (12).

[0179] The contents of the cathode active material, conductive agent, and binder contained in the cathode are at levels typically used in lithium batteries. Depending on the intended use and configuration of the lithium battery, one or more of the conductive agent and binder may be omitted.

[0180] [Anode: Anode current collector]

[0181] The material constituting the positive electrode current collector (11) can be any material that does not react with lithium, that is, any material that does not form an alloy or compound with lithium and has conductivity. The positive electrode current collector (11) is, for example, a metal or an alloy. The positive electrode current collector (11) can be made of, for example, aluminum (Al), indium (In), copper (Cu), magnesium (Mg), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), germanium (Ge) or an alloy thereof. The positive electrode current collector (11) can have a shape selected from, for example, a sheet, a foil, a film, a plate, a porous body, a mesoporous body, a body containing through-holes, a polygonal ring body, a mesh body, a foam body, and a non-woven body, but is not necessarily limited to these shapes, and any shape used in the relevant technical field can be used.

[0182] Alternatively, the cathode current collector (11) may include, for example, a base film and a metal layer disposed on one or both sides of the base film. The base 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 a combination thereof. The polymer may be an insulating polymer. Since the base film includes an insulating thermoplastic polymer, when a short circuit occurs, the base film may soften or liquefy, thereby blocking battery operation and suppressing a sudden increase in current. The metal layer may include, for example, aluminum (Al), indium (In), copper (Cu), magnesium (Mg), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), germanium (Ge), or an alloy thereof. The positive electrode current collector (11) may additionally include a metal piece and / or a lead tab. For more specific details regarding the base film, metal layer, metal chip, and lead tab of the positive electrode current collector (11), refer to the negative electrode current collector (21) described above. By having such a structure, the positive electrode current collector (11) can reduce the weight of the positive electrode, thereby improving the energy density of the positive electrode and the lithium battery.

[0183] [Electrolyte layer]

[0184] [Electrolyte layer: electrolyte]

[0185] The electrolyte layer (30) contains an electrolyte.

[0186] The electrolyte may be, for example, a liquid electrolyte, a solid electrolyte, a gel electrolyte, or a combination thereof.

[0187] Liquid electrolytes are, for example, organic electrolytes. Organic electrolytes are manufactured by dissolving lithium salts in organic solvents.

[0188] Any organic solvent used in the relevant technical field may be used. Examples of the organic solvent include propylene carbonate, ethylene carbonate, fluoroethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, methyl isopropyl carbonate, dipropyl carbonate, dibutyl carbonate, benzonitrile, 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.

[0189] Lithium salts are all possible if they are used as lithium salts in the relevant technical field. Lithium salts include, for example, LiPF6, LiBF4, LiSbF6, LiAsF6, LiClO4, LiCF3SO3, Li(CF3SO2)2N, LiC4F9SO3, LiAlO2, LiAlCl4, LiDFOB, LiN(C x F 2x+1 SO2)(C y F 2y+1 SO2)(1≤x≤20, 1≤y≤20), LiCl, LiI or a mixture thereof. The concentration of the lithium salt is, for example, 0.1 M to 5.0 M.

[0190] The solid electrolyte is, for example, an oxide-based solid electrolyte, a sulfide-based solid electrolyte, a polymer solid electrolyte, or a combination thereof.

[0191] Solid electrolytes are, for example, oxide-based solid electrolytes. Oxide-based solid electrolytes are Li 1+x+y Al x Ti 2-x Si y P 3-y O 12 (0 <x<2, 0≤y<3), BaTiO3, Pb(Zr,Ti)O3(PZT), Pb 1-x La x Zr1-y Ti y O3(PLZT)(0≤x<1, O≤y<1), PB(Mg3Nb 2 / 3 )O3-PbTiO3(PMN-PT), HfO2, SrTiO3, SnO2, CeO2, Na2O, MgO, NiO, CaO, BaO, ZnO, ZrO2, Y2O3, Al2O3, TiO2, SiO2, Li3PO4, Li x Ti y (PO4)3(0 <x<2, 0<y<3), Li x Al y Ti z (PO4)3(0 <x<2, 0<y<1, 0<z<3), Li 1+x+y (Al, Ga) x (Ti, Ge) 2-x Si y P 3-y O 12 (0≤x≤1 0≤y≤1), Li x La y TiO3(0 <x<2, 0<y<3), Li2O, LiOH, Li2CO3, LiAlO2, Li2O-Al2O3-SiO2-P2O5-TiO2-GeO2, Li 3+x La3M2O 12 (M = Te, Nb, or Zr, x is an integer from 1 to 10) is one or more selected from. The solid electrolyte is manufactured by a sintering method, etc. An oxide-based solid electrolyte is, for example, Li7La3Zr2O 12 (LLZO) and Li 3+x La3Zr 2-a M a O 12 A garnet-type solid electrolyte selected from (M doped LLZO, M=Ga, W, Nb, Ta, or Al, x is an integer from 1 to 10).

[0192] The sulfide-based solid electrolyte may include, for example, lithium sulfide, silicon sulfide, phosphorus sulfide, boron sulfide, or a combination thereof. The sulfide-based solid electrolyte particles may include Li2S, P2S5, SiS2, GeS2, B2S3, or a combination thereof. The sulfide-based solid electrolyte particles may be Li2S or P2S5. Sulfide-based solid electrolyte particles are known to have high lithium ion conductivity compared to other inorganic compounds. For example, the sulfide-based solid electrolyte includes Li2S and P2S5. When the sulfide solid electrolyte material constituting the sulfide-based solid electrolyte includes Li2S-P2S5, the mixing molar ratio of Li2S to P2S5 may be, for example, in a range of about 50:50 to about 90:10. In addition, Li3PO4, halogen, halogen compound, Li 2+2x Zn 1-x GeO4("LISICON", 0≤x<1), Li 3+y PO 4-x N x( "LIPON", 0 <x<4, 0<y<3), Li 3.25 Ge 0.25 P 0.75 S4("ThioLISICON"), Li2O-Al2O3-TiO2-P2O 5( An inorganic solid electrolyte prepared by adding "LATP") etc. to an inorganic solid electrolyte of Li2S-P2S5, SiS2, GeS2, B2S3, or a combination thereof can be used as a sulfide solid electrolyte. Non-limiting examples of sulfide solid electrolyte materials include Li2S-P2S5; Li2S-P2S5-LiX (X=halogen element); Li2S-P2S5-Li2O; Li2S-P2S5-Li2O-LiI; Li2S-SiS2; Li2S-SiS2-LiI; Li2S-SiS2-LiBr; Li2S-SiS2-LiCl; Li2S-SiS2-B2S3-LiI; Li2S-SiS2-P2S5-LiI; Li2S-B2S3; Li2S -P2S5-Z m S n(0 <m<10, 0<n<10, Z=Ge, Zn 또는 Ga); Li2S-GeS2; Li2S-SiS2-Li3PO4; 및 Li2S-SiS2-Li p MO q (0 <p<10, 0<q<10, M=P, Si, Ge, B, Al, Ga 또는 In)을 포함한다. 이와 관련하여, 황화물계 고체전해질 재료는 황화물계 고체전해질 물질의 원료 시작 물질(예를 들면, Li2S, P2S5, 등)을 용융 담금질법(melt quenching method), 기계적 밀링법 등에 의해 처리함으로써 제조될 수 있다. 또한, 소성(calcinations) 공정이 상기 처리 후에 수행될 수 있다. 황화물계 고체전해질은 비정질이거나, 결정질이거나, 이들이 혼합된 상태일 수 있다.

[0193] The sulfide-based solid electrolyte may include, for example, an argyrodite type solid electrolyte represented by the following chemical formula 19:

[0194] <Chemical Formula 19>

[0195] Li + 12-n-x A n+ X 2- 6-x Y - x

[0196] In the above formula, A is P, As, Ge, Ga, Sb, Si, Sn, Al, In, Ti, V, Nb or Ta, X is S, Se or Te, Y is Cl, Br, I, F, CN, OCN, SCN or N3, and 1≤n≤5, 0≤x≤2. The sulfide-based solid electrolyte is, for example, Li 7-x PS 6-x Cl x , 0≤x≤2, Li 7-x PS 6-x Br x , 0≤x≤2, and Li 7-x PS 6-x I x, may be an argyrodite-type compound including at least one selected from 0≤x≤2. The sulfide-based solid electrolyte may be, for example, an argyrodite-type compound including at least one selected from Li6PS5Cl, Li6PS5Br, and Li6PS5I.

[0197] The density of the argyrodite-type solid electrolyte may be 0.1 to 2.0 g / cc, 0.5 to 2.0 g / cc, 1.0 to 2.0 g / cc, or 1.5 to 2.0 g / cc. Since the argyrodite-type solid electrolyte has a density in this range, the internal resistance of the solid secondary battery (1) is reduced, and penetration of the solid electrolyte layer by Li can be effectively suppressed.

[0198] The polymer solid electrolyte may, for example, comprise a mixture of a lithium salt and a polymer, or may comprise a polymer having an ion-conducting functional group. The polymer solid electrolyte may, for example, be a polymer electrolyte that is solid at 25°C and 1 atm. The polymer solid electrolyte may, for example, not comprise a liquid.The polymer solid electrolyte comprises a polymer, and the polymer is, 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), polymethyl methacrylate (PMMA, poly(methylmethacrylate), polyethylene glycol (PEG), polyacrylonitrile (PAN), polytetrafluoroethylene (PTFE), polyethylenedioxythiophene (PEDOT), polypyrrole (PPY), Polyacrylonitrile (PAN), polyaniline, polyacetylene, Nafion, Aquivion, Flemion, Gore, Aciplex, Morgane ADP, sulfonated poly(ether ether ketone) (SPEEK), sulfonated poly(arylene ether ketone ketone sulfone) (SPAEKKS), sulfonated poly(aryl ether ketone) (SPAEK), poly[bis(benzimidazobenzisoquinolinones)] (SPBIBI), poly(styrene sulfonate) (PSS), lithium 9,10-Diphenylanthracene-2-sulfonate (lithium 9,10-diphenylanthracene-2-sulfonate, DPASLi. +) or a combination thereof, but is not limited thereto, and any lithium salt that can be used in polymer electrolytes in the relevant technical field is possible. The lithium salt can be any lithium salt that can be used in the relevant technical field. The lithium salt is, for example, LiPF6, LiBF4, LiSbF6, LiAsF6, LiClO4, LiCF3SO3, Li(CF3SO2)2N, LiC4F9SO3, LiAlO2, LiAlCl4, LiN(C x F 2x+1 SO2)(C y F 2y+1 SO2) (x and y are each 1 to 20), LiCl, LiI or a mixture thereof, etc. The polymer included in the polymer solid electrolyte may be, for example, a compound including 10 or more, 20 or more, 50 or more or 100 or more repeating units. The weight average molecular weight of the polymer included in the polymer solid electrolyte may be, for example, 1000 Dalton or more, 10,000 Dalton or more, 100,000 Dalton or more or 1,000,000 Dalton or more.

[0199] A gel electrolyte is, for example, a polymer gel electrolyte. A gel electrolyte can have a gel state without containing a polymer, for example.

[0200] A polymer gel electrolyte may include, for example, a liquid electrolyte and a polymer, or an organic solvent and a polymer having an ion-conducting functional group. The polymer gel electrolyte may be, for example, a polymer electrolyte that is in a gel state at 25°C and 1 atm. The polymer gel electrolyte may, for example, have a gel state without containing a liquid. The liquid electrolyte used in the polymer gel electrolyte may be, for example, a mixture of an ionic liquid, a lithium salt, and an organic solvent; 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 and an ionic liquid. The polymer used in the polymer gel electrolyte may be selected from among the polymers used in solid polymer electrolytes. The organic solvent may be selected from among the organic solvents used in liquid electrolytes. The lithium salt may be selected from among the lithium salts used in solid polymer electrolytes. An ionic liquid refers to a salt that has a melting point below room temperature, is composed solely of ions, and is liquid at room temperature or a molten salt at room temperature. The ionic liquid may include, for example, one or more cations selected from among a) ammonium compounds, pyrrolidinium compounds, pyridinium compounds, pyrimidinium compounds, imidazolium compounds, piperidinium compounds, pyrazolium compounds, oxazolium compounds, pyridazinium compounds, phosphonium compounds, sulfonium compounds, triazolium compounds, and mixtures thereof, and b) one or more anions selected from among 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-. A polymer solid electrolyte can form a polymer gel electrolyte, for example, by being impregnated into a liquid electrolyte in a secondary battery. The polymer gel electrolyte may further include inorganic particles. The polymer included in the polymer gel electrolyte may be, for example, a compound containing 10 or more, 20 or more, 50 or more, or 100 or more repeating units.The weight average molecular weight of the polymer included in the polymer gel electrolyte may be, for example, 500 Dalton or more, 1000 Dalton or more, 10,000 Dalton or more, 100,000 Dalton or more, or 1,000,000 Dalton or more.

[0201] The polymer gel electrolyte may include, for example, a crosslinking product of a crosslinking monomer and a liquid electrolyte. The polymer gel electrolyte may be obtained, for example, by heat treating a precursor composition including a crosslinking monomer and a liquid electrolyte.

[0202] The crosslinking monomer may comprise, for example, 3 to 20, 3 to 10, 3 to 8, or 4 to 6 reactive functional groups. The crosslinking monomer may comprise, for example, an acrylic monomer comprising a plurality of acrylic groups, a methacrylic monomer comprising a plurality of methacrylic groups, or a combination thereof. Acrylic monomers include, for example, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, trimethylolpropane ethoxylate triacrylate, trimethylolpropane propoxylate triacrylate, ditrimethylolpropane tetraacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, pentaerythritol ethoxylate tetraacrylate, dipentaerythritol pentaacrylate, It may contain dipentaerythritol hexaacrylate or a combination thereof.

[0203] The liquid electrolyte can be selected from the liquid electrolytes described above.

[0204] [Electrolyte layer: porous substrate]

[0205] The electrolyte layer (30) may further include a porous substrate in addition to the electrolyte.

[0206] The porous substrate may be, for example, a porous membrane. The porous membrane may be, for example, a microporous membrane. The porous membrane may be, for example, a woven fabric or a non-woven fabric. The porous membrane may be any material commonly used in lithium batteries. The porous membrane may include, for example, glass fiber, an olefin-based resin, a fluoropolymer, an ester-based resin, an imide-based resin, an acrylic resin, a cellulose-based resin, or a combination thereof. The olefin-based resin may include, for example, polyethylene, polypropylene, or a combination thereof. The fluoropolymer-based resin may include, for example, polyvinylidene fluoride, polytetrafluoroethylene, or a combination thereof. The ester-based resin may include, for example, polyethylene terephthalate, polybutylene terephthalate, or a combination thereof. The imide-based resin may include, for example, polyamideimide, polyetherimide, or a combination thereof. The acrylic resin may include, for example, polyacrylonitrile, polyacrylate, or a combination thereof. The cellulosic resin may include, for example, carboxymethylcellulose, microbial cellulose, plant cellulose, animal cellulose, or a combination thereof. The porous substrate may be, for example, a separator.

[0207] The porous substrate is manufactured by the following exemplary methods, but is not limited to these methods and may be adjusted according to required conditions.

[0208] First, a porous membrane-forming composition is prepared by mixing a polymer resin, a filler, and a solvent. The porous membrane can be formed, for example, by directly coating the porous membrane-forming composition on the top of an electrode and drying it. Alternatively, the porous membrane-forming composition can be cast on a support and dried, and then the porous membrane peeled from the support and laminated on the top of an electrode to form a porous membrane. The polymer used in the preparation of the porous membrane is not particularly limited, and the resins described above can be used. Any polymer used as a binder for an electrode can be used. The polymer used in the preparation of the porous membrane can include, for example, a vinylidene fluoride / hexafluoropropylene copolymer, polyvinylidene fluoride (PVDF), polyacrylonitrile, polymethyl methacrylate, or a combination thereof.

[0209] [cathode]

[0210] Referring to FIGS. 1 and 2, a lithium battery (1) according to one embodiment includes a negative electrode (20), and the negative electrode (20) includes a negative electrode current collector (21) and a negative electrode active material layer (22) disposed on the negative electrode current collector (21).

[0211] The negative electrode current collector (21) and the negative electrode active material layer (22) refer to the negative electrode described above.

[0212] [Cathode: Charge capacity ratio]

[0213] The negative electrode active material layer (22) includes a porous structure (23), and the porous structure (23) includes a first negative electrode active material. The negative electrode active material layer (22) includes a first negative electrode active material.

[0214] The initial charge capacity of the negative electrode active material layer (22) may be, for example, 50% or less, 40% or less, 30% or less, 20% or less, or 10% or less of the initial charge capacity of the positive electrode active material layer (12). The ratio (B / A) of the initial charge capacity (B) of the negative electrode active material layer (22) to the initial charge capacity (A) of the positive electrode active material layer (12) is, for example, 0.005 to 0.5, 0.01 to 0.456, 0.01 to 0.5, 0.01 to 0.4, 0.01 to 0.3, 0.01 to 0.2, or 0.01 to 0.1.

[0215] The initial charge capacity of the positive electrode active material layer (12) is determined by the first open circuit voltage (1 st Li / Li from open circuit voltage) + It is determined at the maximum charging voltage. The maximum charging voltage is determined depending on the type of positive electrode material.

[0216] The initial charge capacity of the negative active material layer (22) is the second open circuit voltage (2 nd Li / Li from open circuit voltage) + It is determined at 0.01 V.

[0217] The initial charge capacity (mAh) of the positive electrode active material layer (12) can be obtained by multiplying the charge capacity density (charge specific capacity, mAh / g) of the positive electrode active material by the mass (g) of the positive electrode active material in the positive electrode active material layer (12). When multiple types of positive electrode active materials are used, the charge capacity density × mass value is calculated for each positive electrode active material, and the sum of these values ​​is the initial charge capacity of the positive electrode active material layer (12).

[0218] The initial charge capacity of the negative electrode active material layer (22) is also calculated in the same way. The initial charge capacity of the negative electrode active material layer (22) is obtained by multiplying the charge capacity density (mAh / g) of the first negative electrode active material by the mass of the first negative electrode active material in the negative electrode active material layer (12). When several types of first negative electrode active materials are used, the charge capacity density × mass value is calculated for each first negative electrode active material, and the sum of these values ​​is the initial charge capacity of the negative electrode active material layer (22).

[0219] The charge capacity density of the positive electrode active material and the first negative electrode active material is a capacity measured using a half-cell in which lithium metal is applied to the opposite electrode.

[0220] The initial charge capacity of the positive electrode active material layer (12) and the negative electrode active material layer (22) can be measured using a half-cell using lithium metal as a counter electrode.

[0221] For the positive electrode active material layer (12), the initial charge capacity is determined from the first open circuit voltage (OCV) to the maximum charge voltage, for example, 4.25 V (vs. Li / Li + ) is measured by constant current and constant voltage (CC-CV) charging. Constant current charging is, for example, 0.1 mA / cm 2 can be performed at. Constant voltage charging can be performed until the current decreases to less than 1 / 10 of the amount of current during constant current charging at, for example, 4.25 V. The maximum charging voltage is defined by the standard of JIS C 8712:2015, and for positive electrodes of lithium cobalt oxide type, it means 4.25 V, and for positive electrodes of other types, it means the voltage that can be obtained by applying the provisions of A.3.2.3 (safety requirements when applying other upper limit charging voltages) of JIS C 8712:2015.

[0222] For the negative electrode active material layer (22), the initial charge capacity is measured by constant current and constant voltage (CC-CV) charging from the second open circuit voltage (OCV) to 0.01 V for the negative electrode, for example, lithium metal.

[0223] If the initial charge capacity of the negative electrode active material layer (22) is too small, the thickness of the negative electrode active material layer (22) becomes very thin, so that lithium dendrites formed inside the negative electrode active material layer (22) during repeated charge / discharge processes of the negative electrode active material layer (22) collapse the negative electrode active material layer (22), making it difficult to improve the cycle characteristics of the lithium battery (1). If the charge capacity of the negative electrode active material layer (22) increases excessively, the energy density of the lithium battery (1) may decrease and the internal resistance of the lithium battery (1) due to the negative electrode active material layer (22) may increase, thereby deteriorating the cycle characteristics of the lithium battery (1).

[0224] The thickness of the negative electrode active material layer (22) is, for example, 70% or less, 60% or less, 50% or less, 40% or less, 30% or less, 20% or less, 10% or less, or 5% or less of the thickness of the positive electrode active material layer (12). The thickness of the negative electrode active material layer (22) is, for example, 1 to 70%, 1 to 60%, 1 to 50%, 1 to 40%, 1 to 30%, 1 to 20%, or 1 to 10% of the thickness of the positive electrode active material layer (12). If the thickness of the negative electrode active material layer (22) is too thin, lithium dendrites inside the negative electrode active material layer (22) cause the negative electrode active material layer (22) to collapse, making it difficult to improve the cycle characteristics of the lithium battery (1). If the thickness of the negative electrode active material layer (22) increases excessively, the energy density of the lithium battery (1) decreases and the internal resistance of the lithium battery (1) due to the negative electrode active material layer (22) increases, making it difficult to improve the cycle characteristics of the lithium battery (1). If the thickness of the negative electrode active material layer (22) decreases, the initial charge capacity of the negative electrode active material layer (22) also decreases.

[0225] [Cathode layer: second cathode active material]

[0226] Referring to FIG. 2, the lithium battery (1) further includes, after charging, a second negative electrode active material (25) disposed, for example, within the pores (24) of the negative electrode active material layer (22), i.e., within the pores (24) of the porous structure (23).

[0227] In a lithium battery (1) in which a second negative electrode active material (25) is precipitated by charging after assembly, the energy density per unit weight of the lithium battery (1) increases because the second negative electrode active material (25) is not included when assembling the lithium battery (1). When charging the lithium battery (1), the charging capacity of the negative electrode active material layer (22) is exceeded. That is, the negative electrode active material layer (22) is overcharged. At the beginning of charging, lithium is absorbed into the first negative electrode active material of the porous structure (23) of the negative electrode active material layer (22). The negative electrode active material layer (22) includes the porous structure (23), and the porous structure (23) includes the first negative electrode active material, and the first negative electrode active material absorbs lithium by forming an ionic compound with lithium ions that have moved from the positive electrode (10), for example. When charging exceeds the charge capacity of the negative electrode active material layer (22), for example, lithium is precipitated in the pores (24) of the negative electrode active material layer (22), and a second negative electrode active material (25) is formed by the precipitated lithium. The second negative electrode active material (25) is a metal mainly composed of lithium. This result is obtained because the first negative electrode active material included in the negative electrode active material layer (22) includes an organic negative electrode active material that forms an ionic compound with lithium. When discharging, the lithium arranged in the skeleton of the porous structure (23) of the negative electrode active material layer (22) and the lithium arranged in the pores (24) of the porous structure (23) are ionized and move toward the positive electrode (10). Therefore, it is possible to use lithium as the second negative electrode active material in a lithium battery (1). In addition, since the negative electrode active material layer (22) includes pores (24), the porous structure (23) of the negative electrode active material layer (22) serves as a support for lithium metal, while also suppressing the precipitation and growth of lithium dendrites. Accordingly, short circuits and capacity reduction of the lithium battery (1) are suppressed, and as a result, the cycle characteristics of the lithium battery (1) are improved.In addition, in the lithium battery (1), the negative electrode (20), i.e., the negative electrode current collector (21) and the negative electrode active material layer (22) and the region between them are Li-free regions that do not contain lithium (Li) in the initial state or after complete discharge of the lithium battery (1).

[0228] [Cathode manufacturing method]

[0229] A method for manufacturing a negative electrode according to an embodiment includes the steps of providing a negative electrode current collector; preparing a laminate including a porous precursor structure by electrospinning a solution including a polyimide-based polymer precursor on the negative electrode current collector; and heat-treating the laminate to prepare a negative electrode including a polyimide-based polymer porous structure (23).

[0230] First, a negative electrode current collector is provided. The negative electrode current collector may be nickel foil. For details on the negative electrode current collector, refer to the negative electrode described above.

[0231] Next, a solution containing a polyimide-based polymer precursor is electrospun onto a cathode current collector to prepare a laminate containing a porous precursor structure.

[0232] In a solution containing a polyimide polymer precursor, the content of the polyimide polymer precursor may be, for example, 30 wt% or less, 20 wt% or less, or 10 wt% or less.

[0233] In a solution containing a polyimide polymer precursor, the content of the polyimide polymer precursor may be, for example, 1 to 30 wt%, 1 to 20 wt%, or 1 to 10 wt%.

[0234] A solution containing a polyimide polymer precursor is, for example, a solution containing an organic solvent and polyamic acid.

[0235] A precursor solution containing polyamic acid can be prepared by adding dianhydride and diamine or diisocyanate to an organic solvent and mixing them.

[0236] The type of organic solvent is not particularly limited; any solvent capable of dissolving polyamic acid and used in the relevant technical field may be used. Examples of organic solvents include dimethylacetimide and NMP.

[0237] The type of polyamic acid is not particularly limited, and any precursor of the polyimide polymer of the chemical formulas 1 to 10 described above in the relevant technical field is possible.

[0238] A solution containing a polyimide-based polymer precursor may further contain a conductive agent. The conductive agent content may be 0.1 to 5 parts by weight, 0.1 to 3 parts by weight, or 0.1 to 2 parts by weight, based on 100 parts by weight of the polyimide-based polymer precursor.

[0239] A solution containing a polyimide-based polymer precursor is electrospun onto a negative electrode collector to form a porous precursor structure. The electrospun conditions are not particularly limited, and any conditions capable of spinning a fibrous polymer precursor having a diameter of 10 nm to 500 μm in the relevant technical field are possible. The voltage during electrospun may be 1 kV to 100 kV or 5 kV to 30 kV. The viscosity of the precursor solution can be determined by adjusting the precursor concentration according to the required conditions.

[0240] Next, the laminate is heat-treated to prepare a cathode including a polyamide-based polymer porous structure (23).

[0241] The heat treatment can be performed in an inert atmosphere, such as nitrogen or argon, for example. The heat treatment temperature can be, for example, 100 to 300°C for 1 to 5 hours, but can be controlled within a range capable of forming a polyimide polymer.

[0242] [Lithium Battery Manufacturing Method]

[0243] A method for manufacturing a lithium battery according to one embodiment includes a step of preparing an assembly by laminating a negative electrode, a porous film, and a positive electrode; and a step of preparing a lithium battery by injecting an electrolyte into the assembly and sealing it.

[0244] A positive electrode is prepared. For example, a positive electrode active material composition is prepared by mixing a positive electrode active material, a conductive agent, a binder, and a solvent. The prepared positive electrode active material composition is directly coated on a positive electrode current collector and dried to produce a positive electrode plate having a positive electrode active material layer formed thereon. Alternatively, the positive electrode active material composition is cast on a separate support, and then the film obtained by peeling from the support is laminated on a positive electrode current collector to produce a positive electrode plate having a positive electrode active material layer formed thereon. The solvent is, for example, N-methylpyrrolidone, but is not particularly limited. It is also possible to form pores inside the electrode plate by further adding a plasticizer or a pore forming agent to the positive electrode active material composition. The positive electrode can be prepared by the methods described above, but is not necessarily limited thereto. The types and contents of the positive electrode active material, conductive agent, and binder refer to the positive electrode active material layer described above.

[0245] Prepare the cathode. For more specific information about the cathode, refer to the cathode section above.

[0246] Prepare a porous membrane. For example, a polyethylene separator is used. For more detailed information about the porous membrane, refer to the electrolyte layer section described above.

[0247] An assembly is prepared by laminating a cathode, a porous membrane, and an anode. The assembly is contained in a can or pouch. The porous membrane refers to the electrolyte layer described above.

[0248] Injecting and sealing the electrolyte into the assembly. By injecting the electrolyte into the assembly contained in a can or pouch, the electrolyte is impregnated into the porous membrane.

[0249] The lithium battery (1) may have a structure as shown in FIGS. 6 to 9 below, for example.

[0250] Referring to FIG. 6, a lithium battery (1) according to an embodiment includes a positive electrode (3), the above-described negative electrode (2), and a separator (4). The positive electrode (3), the negative electrode (2), and the separator (4) are wound or folded to form a battery structure (7). The formed battery structure (7) is accommodated in a battery case (5). A composition for forming a positive electrode electrolyte is injected into the battery case (5), cross-linked, and sealed with a cap assembly (6), thereby completing the lithium battery (1). The battery case (5) is cylindrical, but is not necessarily limited to this shape, and may be, for example, square, thin-film, etc.

[0251] Referring to FIG. 7, a lithium battery (1) according to an embodiment includes a positive electrode (3), the above-described negative electrode (2), and a separator (4). The positive electrode (3), the negative electrode (2), and the separator (4) are wound, folded, or laminated to form a battery structure (7). The formed battery structure (7) is accommodated in a battery case (5). A composition for forming a positive electrode electrolyte is injected into the battery case (5), cross-linked, and sealed to complete the lithium battery (1). The battery case (5) is square, but is not necessarily limited to this shape, and may be, for example, cylindrical, thin-film, etc. A positive electrode lead tab (3') and a positive electrode terminal (3") are electrically connected to the positive electrode (3). A negative electrode lead tab (2') and a negative electrode terminal (2") are electrically connected to the negative electrode (2).

[0252] Referring to FIG. 8, a lithium battery (1) according to one embodiment includes a positive electrode (3), the aforementioned negative electrode (2), and a separator (4). A separator (4) is disposed between the positive electrode (3) and the negative electrode (2), and the positive electrode (3), the negative electrode (2), and the separator (4) are wound or folded to form a battery structure (7). The formed battery structure (7) is accommodated in a battery case (5). An electrode tab (8) that serves as an electrical path for guiding a current formed in the battery structure (7) to the outside may be included. A composition for forming a positive electrode electrolyte is injected into the battery case (5), crosslinked, and sealed to complete the lithium battery (1). The battery case (5) is not necessarily limited to a square shape, and may be, for example, a cylindrical shape, a thin film shape, etc.

[0253] Referring to FIG. 9, a lithium battery (1) according to an embodiment includes a positive electrode (3), the aforementioned negative electrode (2), and a separator (4). A separator (4) is disposed between the positive electrode (3) and the negative electrode (2), thereby forming a battery structure. A battery structure (7) is stacked in a bi-cell structure and then accommodated in a battery case (5). An electrode tab (8) serving as an electrical path for guiding a current formed in the battery structure (7) to the outside may be included. A composition for forming a positive electrode electrolyte is injected into the battery case (5), crosslinked, and sealed, thereby completing the lithium metal battery (1). The battery case (5) is not necessarily limited to a square shape, but may be, for example, a cylindrical shape, a thin film shape, etc.

[0254] A pouch-type lithium metal battery uses a pouch as a case for the lithium batteries of FIGS. 6 to 9. The pouch-type lithium battery may include one or more battery structures. A separator is disposed between a positive electrode and a negative electrode to form a battery structure. A plurality of battery structures are laminated in the thickness direction, then impregnated with an organic electrolyte, and accommodated and sealed in a pouch to complete the pouch-type lithium metal battery. For example, although not shown in the drawings, the above-described positive electrode, negative electrode, and separator may be simply laminated and accommodated in a pouch in the form of an electrode assembly, or may be wound or folded into a jellyroll-shaped electrode assembly and then accommodated in a pouch. Subsequently, a composition for forming a positive electrode electrolyte is injected into the pouch, and thermal cross-linking and sealing are performed to complete the lithium battery.

[0255] The lithium battery of the present disclosure has excellent lifespan characteristics and high energy density, making it suitable for use in, for example, electric vehicles (EVs). For example, it is used in hybrid vehicles such as plug-in hybrid electric vehicles (PHEVs). It is also used in applications requiring large amounts of power storage, such as electric bicycles and power tools.

[0256] Lithium batteries are stacked in multiple layers to form a battery module, and the multiple battery modules form a battery pack. Such a battery pack can be used in any device requiring high capacity and high output. For example, it can be used in laptops, smartphones, electric vehicles, etc. The battery module includes, for example, multiple batteries and a frame that holds them. The battery pack includes, for example, multiple battery modules and a bus bar that connects them. The battery module and / or the battery pack may further include a cooling device. The multiple battery packs are controlled by a battery management system. The battery management system includes a battery pack and a battery control device connected to the battery pack.

[0257] As used herein, a substituent is derived by exchanging one or more hydrogen atoms in an unsubstituted mother group with another atom or functional group. Unless otherwise stated, when a functional group is considered to be "substituted," it means that the functional group is substituted with one or more substituents selected from an alkyl group having 1 to 40 carbon atoms, an alkenyl group having 2 to 40 carbon atoms, an alkynyl group having 2 to 40 carbon atoms, a cycloalkyl group having 3 to 40 carbon atoms, a cycloalkenyl group having 3 to 40 carbon atoms, and an aryl group having 7 to 40 carbon atoms. When a functional group is described as being "optionally substituted," it means that the functional group can be substituted with the above-described substituents.

[0258] In this specification, a and b in "carbon atoms a to b" refer to the carbon atoms of a specific functional group. That is, the functional group may include carbon atoms from a to b. For example, "an alkyl group having 1 to 4 carbon atoms" refers to an alkyl group having 1 to 4 carbon atoms, i.e., CH3-, CH3CH2-, CH3CH2CH2-, (CH3)2CH-, CH3CH2CH2CH2-, CH3CH2CH(CH3)-, and (CH3)3C-.

[0259] The nomenclature for a particular radical may include either a monoradical or a diradical, depending on the context. For example, if a substituent requires two points of attachment to the rest of the molecule, the substituent should be understood as a diradical. For example, a substituent specified as an alkyl group requiring two points of attachment includes diradicals such as -CH2-, -CH2CH2-, -CH2CH(CH3)CH2-, etc. Other radical nomenclatures, such as "acylene," clearly indicate that the radical is a diradical.

[0260] As used herein, the term "alkyl group" or "alkylene group" refers to a branched or unbranched aliphatic hydrocarbon group. In one embodiment, the alkyl group can be substituted or unsubstituted. The alkyl group includes, but is not necessarily limited to, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, hexyl, cyclopropyl, cyclopentyl, cyclohexyl, cycloheptyl, and the like, each of which can be optionally substituted or unsubstituted. In one embodiment, the alkyl group can have 1 to 6 carbon atoms. For example, the alkyl group having 1 to 6 carbon atoms can be, but is not necessarily limited to, methyl, ethyl, propyl, isopropyl, butyl, iso-butyl, sec-butyl, pentyl, 3-pentyl, hexyl, and the like.

[0261] As used herein, the term "alkenyl group" refers to a hydrocarbon group having 2 to 20 carbon atoms, including at least one carbon-carbon double bond, including but not limited to an ethenyl group, a 1-propenyl group, a 2-propenyl group, a 2-methyl-1-propenyl group, a 1-butenyl group, a 2-butenyl group, a cyclopropenyl group, a cyclopentenyl group, a cyclohexenyl group, a cycloheptenyl group, and the like. In one embodiment, the alkenyl group can be substituted or unsubstituted. In one embodiment, the alkenyl group can have 2 to 40 carbon atoms.

[0262] As used herein, the term "alkynyl group" refers to a hydrocarbon group having 2 to 20 carbon atoms, including at least one carbon-carbon triple bond, including, but not limited to, an ethynyl group, a 1-propynyl group, a 1-butynyl group, a 2-butynyl group, and the like. In one embodiment, the alkynyl group may be substituted or unsubstituted. In one embodiment, the alkynyl group may have 2 to 40 carbon atoms.

[0263] As used herein, the term "cycloalkyl group" means a fully saturated carbocyclic ring or ring system, such as cyclopropyl, cyclobutyl, cyclopentyl, or cyclohexyl.

[0264] As used herein, the term "aromatic" means a ring or ring system having a conjugated pi electron system, including carbocyclic aromatics (e.g., a phenyl group) and heterocyclic aromatics (e.g., pyridine). The term includes monocyclic rings or fused polycyclic rings (i.e., rings that share adjacent pairs of atoms) if the entire ring system is aromatic.

[0265] As used herein, the term "aryl group" means an aromatic ring, a ring system (i.e., two or more fused rings sharing two adjacent carbon atoms), or a ring in which multiple aromatic rings are connected to each other by a single bond, -O-, -S-, -C(=O)-, -S(=O)2-, -Si(Ra)(Rb)- (Ra and Rb are each independently an alkyl group having 1 to 10 carbon atoms), an alkylene group having 1 to 10 carbon atoms which is unsubstituted or substituted with a halogen, or -C(=O)-NH-. When the aryl group is a ring system, each ring in the system is aromatic. For example, aryl groups include, but are not limited to, a phenyl group, a biphenyl group, a naphthyl group, a phenanthrenyl group, a naphthacenyl group, and the like. The aryl group may be substituted or unsubstituted.

[0266] The term "arylene group" as used herein refers to an aryl group requiring two or more connection points. A tetravalent arylene group is an aryl group requiring four connection points, and a divalent arylene group is an aryl group requiring two connection points. For example, -C6H5-O-C6H5-.

[0267] As used herein, the term "heteroaryl group" means an aromatic ring system having one ring, multiple fused rings, or multiple rings joined to each other by a single bond, -O-, -S-, -C(=O)-, -S(=O)2-, -Si(Ra)(Rb)- (Ra and Rb are each independently an alkyl group having 1 to 10 carbon atoms), a halogen-substituted or unsubstituted alkylene group having 1 to 10 carbon atoms, or -C(=O)-NH-, wherein at least one ring atom is not carbon, i.e., a heteroatom. In a fused ring system, one or more heteroatoms can be present in only one ring. For example, heteroatoms include, but are not necessarily limited to, oxygen, sulfur, and nitrogen. For example, the heteroaryl group may be, but is not limited to, a furanyl group, a thienyl group, an imidazolyl group, a quinazolinyl group, a quinolinyl group, an isoquinolinyl group, a quinoxalinyl group, a pyridinyl group, a pyrrolyl group, an oxazolyl group, an indolyl group, etc.

[0268] The term "heteroarylene group" as used herein refers to a heteroaryl group requiring two or more connection points. A tetravalent heteroarylene group is a heteroaryl group requiring four connection points, and a divalent heteroarylene group is a heteroaryl group requiring two connection points.

[0269] As used herein, the terms "aralkyl group" and "alkylaryl group" refer to an aryl group linked as a substituent via an alkylene group, such as an aralkyl group having 7 to 14 carbon atoms, including but not limited to a benzyl group, a 2-phenylethyl group, a 3-phenylpropyl group, and a naphthylalkyl group. In one embodiment, the alkylene group is a lower alkylene group (i.e., an alkylene group having 1 to 4 carbon atoms).

[0270] As used herein, a "cycloalkenyl group" is a carbocyclic ring or ring system having one or more double bonds, and is a ring system without an aromatic ring. For example, a cyclohexenyl group.

[0271] As used herein, “heterocyclyl group” is a non-aromatic ring or ring system containing one or more heteroatoms in the ring skeleton.

[0272] As used herein, “halogen” means a stable element belonging to group 17 of the periodic table of elements, for example, fluorine, chlorine, bromine or iodine, and in particular, fluorine and / or chlorine.

[0273] The weight average molecular weight of the first to third polymers is measured by GPC (Gel Permeation Chromatography) with respect to a polystyrene standard sample.

[0274] The present invention is explained in more detail through the following examples and comparative examples. However, the examples are intended to illustrate the present invention and are not intended to limit the scope of the present invention.

[0275] (cathode)

[0276] Example 1: Polyimide (PI1) porous structure

[0277] After filling the flask with nitrogen, pyromellitic dianhydride (PMDA) and 4,4'-oxydianiline (ODA) were added in a molar ratio of 1:1 to dimethylacetamide (DMAc) solvent, stirred at room temperature for 24 hours, and polymerized to prepare a uniform polyamic acid (PAA) precursor solution. The acid equivalent of the polyamic acid was 210 g / eq, and the weight average molecular weight (Mw) was approximately 1,000,000 Dalton.

[0278] A polyamic acid solution was electrospun onto a nickel current collector having a thickness of 10 μm to form a web of fibrous polymer. A laminate comprising a nickel current collector and a fibrous polymer web disposed on the nickel current collector was prepared. The voltage applied to the electrospinning was 14 kV. The prepared laminate was heat-treated at 300°C for 2 hours in a nitrogen atmosphere to prepare a porous structure containing a polyimide represented by the following chemical formula 1a. An anode was prepared by disposing a negative electrode active material layer including the porous structure on a nickel current collector.

[0279] In chemical formula 1a, n is the degree of polymerization, which is 2,000 to 10,000.

[0280] <Chemical Formula 1a>

[0281]

[0282] Figure 3 is a scanning electron microscope image of the negative electrode active material layer manufactured in Example 1.

[0283] As shown in Fig. 3, the polyimide porous structure had a three-dimensional network structure including fibrous polymers. The aspect ratio of the fibrous polymers was 10 or more. The diameter of the fibrous polymers was approximately 0.6 μm.

[0284] The fibrous polymers are arranged irregularly and / or non-periodically within the porous structure.

[0285] The pore size of the polyimide porous structure was approximately 0.2 to 3 μm, and the porosity of the porous structure was approximately 72%. A plurality of pores were arranged irregularly and / or non-periodically within the porous structure.

[0286] The thickness of the negative electrode active material layer composed of a porous structure was approximately 70 μm. The negative electrode active material layer is, for example, a polymer porous membrane or polymer porous web composed of polymer fibers.

[0287] The negative active material layer does not contain a separate binder.

[0288] Example 2: Polyimide + N-dopd CNT porous structure

[0289] A cathode was manufactured in the same manner as in Example 1, except that the polyamic acid precursor solution additionally contained nitrogen-doped carbon nanotubes (N-doped CNTs) as a conductive agent.

[0290] The content of the conductive agent was 0.1 part by weight per 100 parts by weight of polyamic acid.

[0291] Example 3: Polyimide + undopd CNT porous structure

[0292] A cathode was manufactured in the same manner as in Example 1, except that the polyamic acid precursor solution additionally contained undoped carbon nanotubes (undoped CNTs) as a conductive agent.

[0293] The content of the conductive agent was 0.1 part by weight per 100 parts by weight of polyamic acid.

[0294] Example 4: Polyimide (PI2) porous structure

[0295] A negative electrode was manufactured in the same manner as in Example 1, except that a polyimide represented by the following chemical formula 1b was used instead of the polyimide represented by the chemical formula 1a.

[0296] A polyimide represented by chemical formula 1b was prepared using N-methylpyrrolidone (NMP) solvent and a 1:1 molar ratio mixture of pyromellitic dianhydride (PMDA) and terephthalimide as a solvent and starting material, respectively.

[0297] In chemical formula 1b, n is the degree of polymerization, which is 2,000 to 10,000.

[0298] <Chemical Formula 1b>

[0299]

[0300] Example 5: Polyamideimide (PAI) porous structure

[0301] A negative electrode was manufactured in the same manner as in Example 1, except that polyamideimide represented by the following chemical formula 2a was used instead of the polyimide represented by the chemical formula 1a.

[0302] In chemical formula 2a, n is the degree of polymerization, which is 2,000 to 10,000.

[0303] <Chemical Formula 2a>

[0304]

[0305] Example 6: Polyetherimide (PEI) porous structure

[0306] A negative electrode was manufactured in the same manner as in Example 1, except that polyetherimide represented by the following chemical formula 3a was used instead of the polyimide represented by the chemical formula 1a.

[0307] In chemical formula 3a, n is the degree of polymerization, which is 2,000 to 10,000.

[0308] <Chemical Formula 3a>

[0309]

[0310] Comparative Example 1: Nickel negative electrode current collector

[0311] A negative electrode was manufactured in the same manner as in Example 1, except that a nickel current collector was used as the negative electrode without a porous structure.

[0312] Comparative Example 2: Polyacrylonitrile (PAN) porous structure

[0313] A negative electrode was manufactured in the same manner as in Example 1, except that polyacrylonitrile was used instead of polyamide.

[0314] The weight average molecular weight of polyacrylonitrile was 150,000 Dalton.

[0315] Comparative Example 3: Polyacrylonitrile (PAN) film

[0316] A negative electrode was manufactured in the same manner as in Example 1, except that polyacrylonitrile was used instead of polyamide and a film was used instead of a porous structure.

[0317] The weight average molecular weight of polyacrylonitrile was 150,000 Dalton.

[0318] A cathode comprising a polyacrylonitrile film was manufactured by coating a precursor solution comprising polyacrylonitrile directly onto a nickel current collector without field radiation and drying the solution.

[0319] The polyacrylonitrile film did not contain fibrous polymers or porous structures.

[0320] (lithium battery)

[0321] Example 7

[0322] (Polar electrode manufacturing)

[0323] LiNi 0.8 Co 0.15 Al 0.05O2(NCA) powder and carbon conductive material (Super-P; Timcal Ltd.) were uniformly mixed at a weight ratio of 90:5, and then PVDF (polyvinylidene fluoride) binder solution was added to prepare a positive electrode active material slurry so that the weight ratio of active material:carbon conductive material:binder = 90:5:5. The prepared slurry was coated on a 20 ㎛ thick aluminum substrate using a doctor blade, dried under reduced pressure at 120 ℃, and then rolled into a sheet using a roll press to prepare a positive electrode. The thickness of the positive electrode active material layer was 80 ㎛.

[0324] (Cathode manufacturing)

[0325] The cathode manufactured in Example 1 was used.

[0326] (lithium battery manufacturing)

[0327] A polypropylene / polyethylene / polypropylene triple separator was placed between the manufactured positive electrode and the negative electrode manufactured in Example 1 to prepare a laminate. The liquid electrolyte manufactured in Manufacturing Example 1 was injected into the prepared laminate to manufacture a lithium battery.

[0328] The liquid electrolyte was prepared by adding 0.6 M LiBF4 and 0.6 M LiDFOB (lithium difluoro(oxalate)borate) to a 2:1 volume ratio mixed solvent of diethyl carbonate (DEC) and fluoroethylene carbonate (FEC).

[0329] (Initial charge capacity ratio)

[0330] A first half-cell was manufactured in the same manner as the lithium battery of Example 7, except that lithium metal was used as a counter electrode for the positive electrode manufactured in Example 7.

[0331] A second half-cell was manufactured in the same manner as the lithium battery of Example 7, except that lithium metal was used as a counter electrode for the negative electrode manufactured in Example 1.

[0332] For the first half cell, the maximum charge voltage from the first open circuit voltage (OCV), 4.2 V (vs. Li / Li + ) was charged with constant current and constant voltage (CC-CV) to measure the initial charge capacity (A) of the positive electrode active material layer.

[0333] For the second half-cell, the initial charge capacity (B) of the negative electrode active material layer was measured by charging with constant current and constant voltage (CC-CV) from the second open circuit voltage (OCV) to 0.01 V with respect to lithium metal.

[0334] The ratio (B / A) of the initial charge capacity (B) of the negative electrode active material layer (22) and the initial charge capacity (A) of the positive electrode active material layer (12) was 0.09.

[0335] Examples 8 to 12

[0336] A lithium battery was manufactured in the same manner as in Example 6, except that the negative electrode manufactured in Examples 2 to 6 was used instead of the negative electrode manufactured in Example 1.

[0337] Comparative examples 4 to 6

[0338] A lithium battery was manufactured in the same manner as in Example 6, except that the negative electrode manufactured in Comparative Examples 1 to 3 was used instead of the negative electrode manufactured in Example 1.

[0339] Evaluation Example 1: Electrochemical Activity Evaluation

[0340] Coin cells were prepared using lithium metal as a counter electrode for the negative electrodes manufactured in Examples 1 to 6 and Comparative Example 1.

[0341] A coin cell was prepared by placing a polypropylene / polyethylene / polypropylene triple separator between the cathode and the counter electrode, injecting electrolyte, and sealing.

[0342] The liquid electrolyte was prepared by adding 0.6 M LiBF4 and 0.6 M LiDFOB (lithium difluoro(oxalate)borate) to a 2:1 volume ratio mixed solvent of diethyl carbonate (DEC) and fluoroethylene carbonate (FEC).

[0343] The manufactured coin cells were scanned at a rate of 1 mV / s between 0 and 3.5 V (vs. Li) using cyclic voltammetry.

[0344] Figure 4 is a cyclic voltammogram of the first to third cycles of a coin cell using the negative electrode manufactured in Example 1.

[0345] Figure 5 is a cyclic voltammogram of the first to third cycles of a coin cell using the negative electrode manufactured in Comparative Example 1.

[0346] As shown in FIGS. 4 and 5, the cathode of Example 1 exhibited additional oxidation peaks and / or reduction peaks that were distinct from the cathode of Comparative Example 1.

[0347] In Example 1, it was confirmed that additional oxidation peaks and / or reduction peaks were obtained due to association and / or dissociation of polyimide and lithium ions.

[0348] It was confirmed that polyimide possesses electrochemical activity. Therefore, it was confirmed that polyimide can be used as an anode active material.

[0349] Although not shown in the drawing, the cathodes manufactured in Examples 2 to 5 also exhibited additional oxidation peaks and / or reduction peaks.

[0350] Evaluation Example 2: Charge / Discharge Test

[0351] A high-temperature (45°C) charge-discharge test was performed on the lithium batteries of Examples 7 to 12 and Comparative Examples 4 to 6 under the following conditions.

[0352] The lithium battery was charged at a constant current of 0.2 C at 45°C until the voltage reached 4.3 V (vs. Li). Subsequently, it was discharged at a constant current of 0.5 C until the voltage reached 3.6 V (vs. Li).

[0353] This charge-discharge cycle was repeated 100 times.

[0354] In all charge / discharge cycles, a 5-minute pause was provided after each charge / discharge cycle. The results of the room-temperature charge / discharge experiments are shown in Table 1 below. The capacity retention rate is defined by the following mathematical equation (1).

[0355] <Mathematical Formula 1>

[0356] Capacity retention rate [%] = [100 th Discharge capacity in cycles / 1 st Discharge capacity in cycle] × 100

[0357] Capacity retention [%] Example 7 Polyimide (PI1) porous structure 82.9 Example 8 Polyimide (PI1) porous structure + N-doped CNT 88.8 Example 9 Polyimide (PI1) porous structure + undoped CNT 85.6 Example 10 Polyimide (PI2) porous structure 81.2 Example 11 Polyamideimide (PAI) porous structure 71.5 Example 12 Polyetherimide (PEI) porous structure 72.3 Comparative Example 4 Nickel negative electrode current collector 65.2

[0358] As shown in Table 1, the lithium batteries of Examples 7 to 12 having the negative electrodes of Examples 1 to 6 had improved life characteristics compared to the lithium battery of Comparative Example 4 having the negative electrode of Comparative Example 1.

[0359] It was determined that this was because, in the lithium batteries of Examples 7 to 12 equipped with the negative electrodes of Examples 1 to 6, the negative electrode active material layer provided lithium nucleation sites, thereby enabling uniform lithium deposition and dissolution, and suppressing volume changes in the negative electrode active material layer by accommodating the lithium deposited within the porous structure.

[0360] It was determined that the lithium battery of Comparative Example 4 equipped with the negative electrode of Comparative Example 1 had a deterioration in cycle characteristics due to non-uniform lithium deposition and dissolution as the negative electrode contained only the negative electrode current collector.

[0361] Although not shown in Table 1, the lithium battery of Comparative Example 5 equipped with the negative electrode of Comparative Example 2 had poor cycle characteristics compared to the lithium batteries of Examples 7 to 12. It was determined that the poor cycle characteristics were due to uneven lithium deposition and dissolution as a result of the polyacrylonitrile in the lithium battery of Comparative Example 5 not having electrochemical activity.

[0362] Although not shown in Table 1, the lithium battery of Comparative Example 6 equipped with the negative electrode of Comparative Example 3 had poor cycle characteristics compared to the lithium batteries of Examples 7 to 12. It was determined that the poor cycle characteristics were due to the polyacrylonitrile film in the lithium battery of Comparative Example 6 acting as a type of insulator between the electrolyte and the negative electrode current collector.

[0363] While exemplary embodiments have been described in detail with reference to the attached drawings, the present invention is not limited to these examples. It is self-evident that those skilled in the art to which the present invention pertains can devise various modifications or variations within the scope of the technical concepts described in the patent claims, and these also naturally fall within the technical scope of the present invention.

[0364] [Explanation of symbols]

[0365] 1 lithium battery 2, 20 cathode

[0366] 2' negative lead tab 2" negative terminal

[0367] 3, 10 positive 3' positive lead tab

[0368] 3" positive terminal 4 separator

[0369] 5 Battery case 6 Cap assembly

[0370] 7 Battery structure 8 Electrode tab

[0371] 11. Anode current collector 12. Anode active material layer

[0372] 21 Negative current collector 22 Negative active material layer

[0373] 23 Porous structure 24 Pores

[0374] 25 Second negative electrode active material 30 Electrolyte

[0375] According to one aspect, it is possible to provide a negative electrode in which volume change is suppressed during charge and discharge by having a porous structure capable of associating and dissociating lithium ions.

[0376] According to another aspect, it is possible to provide a lithium battery having improved cycle characteristics by having the above-described negative electrode.

Claims

1. A negative electrode current collector; and a negative electrode active material layer on one surface of the negative electrode current collector, The above negative electrode active material layer includes a porous structure, The above porous structure includes a first negative electrode active material, The above first negative electrode active material includes an organic negative electrode active material, A cathode, wherein the organic cathode active material comprises a polyimide-based polymer.

2. In the first paragraph, the porous structure is a porous three-dimensional structure, The above porous structure comprises a fibrous polymer, The aspect ratio of the above fibrous polymer is 5 or more, A cathode having a diameter of the above fibrous polymer of 10 nm to 500 ㎛.

3. In the first paragraph, the porous structure has a three-dimensional network structure including a plurality of fibrous polymers connected to each other, A cathode, wherein the porous structure comprises a plurality of fibrous polymers arranged irregularly or non-periodically.

4. In the first paragraph, the porosity of the porous structure is 10 to 90%, The porous structure comprises a plurality of pores that are irregularly or non-periodically arranged within the porous structure, A cathode having a pore size of 10 nm to 10 ㎛.

5. In the first paragraph, the porous structure is a polymer porous structure, The above polymer porous structure includes a polymeric porous film or a polymeric porous web, A cathode having a thickness of the porous structure of 1 to 200 ㎛.

6. In the first paragraph, the polyimide polymer contains an imide repeating unit, The above polyimide polymer includes polyimide, polyamideimide, polyetherimide or a combination thereof, A cathode having a molecular weight of the polyimide polymer of 1,000 to 5,000,000 Daltons.

7. In the first paragraph, the negative electrode comprises a polymer represented by the following chemical formulas 1 to 3: <Chemical Formula 1> <Chemical Formula 2> <Chemical Formula 3> In the above formulas, Ar1 is an aromatic ring group selected from a substituted or unsubstituted tetravalent arylene group having 6 to 24 carbon atoms or a substituted or unsubstituted tetravalent heteroarylene group having 4 to 24 carbon atoms, The above aromatic ring group is a ring in which one aromatic ring, two or more aromatic rings are fused, or two or more aromatic rings are connected by a single bond, -O-, -S-, -C(=O)-, -S(=O)2-, -Si(Ra)(Rb)- (Ra and Rb are each independently an alkyl group having 1 to 10 carbon atoms), an alkylene group having 1 to 10 carbon atoms substituted or unsubstituted with a halogen, or -C(=O)-NH-O. Ar3, Ar5 and Ar6 are independently an aromatic ring group selected from a substituted or unsubstituted trivalent arylene group having 6 to 24 carbon atoms or a substituted or unsubstituted trivalent heteroarylene group having 4 to 24 carbon atoms, The above aromatic ring group is a ring in which one aromatic ring, two or more aromatic rings are fused, or two or more aromatic rings are connected by a single bond, -O-, -S-, -C(=O)-, -S(=O)2-, -Si(Ra)(Rb)- (Ra and Rb are each independently an alkyl group having 1 to 10 carbon atoms), an alkylene group having 1 to 10 carbon atoms substituted or unsubstituted with a halogen, or -C(=O)-NH-O. Ar2, Ar4, Ar7 and Ar8 are independently an aromatic ring group selected from a substituted or unsubstituted divalent arylene group having 6 to 24 carbon atoms or a substituted or unsubstituted divalent heteroarylene group having 4 to 24 carbon atoms, The above aromatic ring group is a ring in which one aromatic ring, two or more aromatic rings are fused, or two or more aromatic rings are connected by a single bond, -O-, -S-, -C(=O)-, -S(=O)2-, -Si(Ra)(Rb)- (Ra and Rb are each independently an alkyl group having 1 to 10 carbon atoms), an alkylene group having 1 to 10 carbon atoms substituted or unsubstituted with a halogen, or -C(=O)-NH-. X1, X2, X3, X4, X5, X6, X7 and X8 are each independently a single bond, -O-, -S-, -C(=O)-, -S(=O)2-, -Si(Ra)(Rb)- (Ra and Rb are each independently a C1-C10 alkyl group), a C1-C10 alkylene group substituted or unsubstituted with a halogen, or a ring connected by -C(=O)-NH-, n is between 2 and 20,000.

8. A negative electrode in the first paragraph, wherein the negative electrode active material layer is binder-free.

9. In the first paragraph, the porous structure further includes a conductive material, The above-mentioned conductive material includes a carbon-based conductive material, a metal-based conductive material, or a combination thereof, An anode, wherein the carbon-based conductive material comprises carbon black, acetylene black, furnace black, ketjen black, graphene, graphene oxide, reduced graphene oxide, carbon fiber, carbon nanotube (CNT), or a combination thereof.

10. In the 9th paragraph, the carbon-based conductive material comprises a doped carbon-based conductive material, A cathode, wherein the doped carbon-based conductive material comprises a dopant, and the dopant comprises nitrogen (N), sulfur (S), fluorine (F), chlorine (Cl) or a combination thereof.

11. A cathode in the first paragraph, wherein the content of the conductive material is 0.1 to 5 wt% of the total weight of the porous structure.

12. In the first paragraph, the negative electrode active material layer further includes a second negative electrode active material arranged within the pores of the porous structure, A negative electrode, wherein the second negative electrode active material comprises lithium metal, a lithium alloy, or a combination thereof.

13. A negative electrode in the first paragraph, wherein the negative electrode collector comprises copper, nickel, nickel-coated copper, stainless steel, iron (Fe), cobalt (Co), or an alloy thereof.

14. In the 11th paragraph, the negative electrode collector includes a base film and a metal layer disposed on one or both sides of the base film, The above base film comprises a polymer, and the polymer comprises polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP), polybutylene terephthalate (PBT), polyimide (PI) or a combination thereof. A cathode, wherein the metal layer comprises indium (In), copper (Cu), magnesium (Mg), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), aluminum (Al), germanium (Ge), lithium (Li) or an alloy thereof.

15. A cathode including a cathode current collector; and a cathode active material layer on one surface of the cathode current collector; A cathode according to any one of claims 1 to 14; and A lithium battery comprising an electrolyte layer disposed between the positive electrode and the negative electrode.

16. In clause 15, the positive electrode active material layer includes a positive electrode active material, The above cathode active material includes a sulfide-based cathode active material, an oxide-based cathode active material, or a combination thereof. The above sulfide-based cathode active material includes nickel sulfide, copper sulfide, Li2S, a Li2S-containing complex, or a combination thereof. A lithium battery, wherein the oxide-based cathode active material comprises a lithium transition metal oxide, a metal oxide, or a combination thereof, and the lithium transition metal oxide comprises lithium cobalt oxide, lithium nickel oxide, lithium nickel cobalt oxide, lithium nickel cobalt aluminium oxide, lithium nickel cobalt mangense oxide, lithium manganate, lithium iron phosphate, or a combination thereof, and the lithium oxide comprises iron oxide, vanadium oxide, or a combination thereof.

17. In the 15th paragraph, the electrolyte layer further includes a liquid electrolyte, a solid electrolyte, a gel electrolyte or a combination thereof, The above solid electrolyte includes a sulfide-based solid electrolyte, an oxide-based solid electrolyte, a polymer solid electrolyte, or a combination thereof. A lithium battery, wherein the gel electrolyte comprises a polymer gel electrolyte.

18. In the 15th paragraph, the negative electrode includes a negative electrode active material layer, A lithium battery, wherein the initial charge capacity of the negative electrode active material layer is 50% or less of the initial charge capacity of the positive electrode active material layer.

19. Step of providing a cathode collector; A step of preparing a laminate including a porous precursor structure by electrospinning a solution including a polyimide-based polymer precursor on the negative electrode current collector; and A method for manufacturing a cathode, comprising the step of heat-treating the laminate to prepare a cathode including a polyamide-based polymer porous structure.

20. In the 19th paragraph, the content of the polyimide polymer precursor in the solution containing the polyimide polymer precursor is 30 wt% or less, A solution containing the above polyimide-based polymer precursor includes a solvent, The above solvent contains dimethylacetimide, The solution containing the above polyimide-based polymer precursor further contains a conductive material, A method for manufacturing a cathode, wherein the above heat treatment is performed in an inert atmosphere at 100 to 300° C. for 1 to 5 hours.

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