Negative electrode-free battery

Abstract

The present invention relates to an anode-less battery including a positive electrode, a negative electrode facing the positive electrode, and a separator and an electrolyte interposed between the positive electrode and the negative electrode, wherein the positive electrode includes a positive electrode active material, and the positive electrode active material includes a lithium transition metal oxide, the negative electrode includes a negative electrode current collector for an anode-less battery, and the negative electrode current collector for an anode-less battery includes a metal current collecting substrate, and the metal current collecting substrate includes a space portion at least a portion of which is exposed to the outside, and the battery satisfies a specific relational formula.

Description

[Technical Field]

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0181138, filed December 21, 2022, and all contents disclosed in the documents of this Korean patent application are incorporated herein by reference.

[0002] The present invention relates to a negative electrode-less battery. [Background technology]

[0003] In recent years, the development of the information society has led to the development of personal IT devices and computer networks, which has increased society's overall dependence on electrical energy. This has led to a demand for the development of battery technology that can efficiently store and utilize electrical energy.

[0004] In particular, there is growing interest in solving environmental problems and realizing a sustainable, recycling-oriented society, and research into energy storage devices such as lithium-ion batteries and electric double-layer capacitors is being widely conducted. Of these, lithium secondary batteries are attracting attention as the battery system with the highest theoretical energy density of all battery technologies.

[0005] Typically, a lithium secondary battery has a structure in which an electrolyte is impregnated into an electrode assembly consisting of a positive electrode, a negative electrode, and a separator. The positive electrode is typically fabricated by coating an aluminum foil with a positive electrode mixture containing a positive electrode active material, and the negative electrode is typically fabricated by coating a copper foil with a negative electrode mixture containing a negative electrode active material. In this case, a lithium transition metal oxide is typically used as the positive electrode active material, and a carbon-based active material, a silicon-based active material, or the like is typically used as the negative electrode active material.

[0006] In recent years, lithium metal batteries, which use lithium metal itself as the negative electrode active material, have been commercialized, and research is also underway into negative electrode-free batteries (also known as anode-free batteries), in which only the negative electrode current collector is used as the negative electrode during electrode manufacture, while lithium is provided from the positive electrode during charging, using lithium metal as the negative electrode active material. Because negative electrode-free batteries do not contain a negative electrode mixture layer, they can contain a larger positive electrode mixture layer, making them preferable from the perspective of high energy density.

[0007] However, during charging of the anodeless battery, lithium transferred from the positive electrode may be electrodeposited on the anode current collector, forming lithium dendrites. The growth of lithium dendrites increases irreversible capacity, which can lead to reduced charge / discharge efficiency. Furthermore, during charging of the anodeless battery, the lithium metal layer formed on the anode current collector has a low electrodeposition density, which can cause side reactions in the electrolyte, resulting in a rapid decrease in lifespan.

[0008] Korean Patent Publication No. 10-2019-0083878 discloses a negative electrode-less lithium metal battery, but does not provide an alternative to the above-mentioned problems. [Prior art documents] [Patent documents]

[0009] Patent Document 1: Korean Patent Publication No. 10-2019-0083878 Summary of the Invention [Problem to be solved by the invention]

[0010] An object of the present invention is to provide a negative electrode-less battery that suppresses the formation of lithium dendrites during charge and discharge, thereby improving charge and discharge efficiency and life performance. [Means for solving the problem]

[0011] The present invention provides an anodeless battery including a positive electrode, an anode facing the positive electrode, a separator and an electrolyte interposed between the positive electrode and the anode, wherein the positive electrode includes a positive electrode active material, and the positive electrode active material includes a lithium transition metal oxide, the anode includes a negative electrode current collector for the anodeless battery, and the negative electrode current collector for the anodeless battery includes a metal current collecting substrate, and the metal current collecting substrate includes a space at least partially exposed to the outside, and the battery satisfies the following mathematical formula 1:

[0012] [Mathematical formula 1] 0.7V≦(n×L×V Li ) / M p ≦2.0V

[0013] In the above mathematical formula 1, V is the volume of the space (unit: ml), n is a value (unitless) calculated by the following mathematical formula 2, L is the loading weight of the positive electrode active material in the positive electrode (unit: g), and V Li is the volume per mole of lithium metal (unit: ml / mol), and M p is the molar mass of the lithium transition metal oxide (unit: g / mol).

[0014] [Mathematical formula 2] n=C H ×M p ×1 / 96485mol / C×3600s / h

[0015] In the above mathematical formula 2, C H is the capacity (unit: Ah / g) of the half cell made from the positive electrode and lithium metal counter electrode, and M p is the molar mass of the lithium transition metal oxide (unit: g / mol), C is the unit of coulomb, s is the unit of second, and h is the unit of hour. [Effects of the Invention]

[0016] The anodeless battery according to the present invention includes a positive electrode and a negative electrode. The positive electrode includes a positive electrode active material including a lithium transition metal oxide. The anode uses a current collector for anodeless batteries that does not include anode active materials such as carbon or silicon. The current collector for anodeless batteries includes a metal current collector substrate having a void space at least partially exposed to the outside, and the void space and the lithium volumetric relationship of the lithium transition metal oxide in the positive electrode satisfy the following mathematical formula (Equation 1). By satisfying this formula, the anodeless battery according to the present invention can smoothly plate lithium from the positive electrode into the void space of the metal current collector substrate, thereby reducing the expansion of the anode and minimizing the formation of lithium dendrites. As a result, the anodeless battery according to the present invention can suppress the formation of lithium dendrites, ensuring safety, and exhibiting improved energy density, excellent charge / discharge efficiency, and lifespan. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 2 is a schematic side view of a negative electrode according to one embodiment of the present invention. [Figure 2] FIG. 1 is a schematic perspective view of a negative electrode according to one embodiment of the present invention. [Figure 3] 1 is a schematic side view of a negative electrode according to another embodiment of the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0018] The terms and words used in this specification and claims should not be interpreted in a limited way to their ordinary or dictionary meanings, but should be interpreted in a way that is consistent with the technical idea of ​​the present invention, based on the principle that the inventors can appropriately define the concepts of terms in order to best explain their inventions.

[0019] Furthermore, in this specification, the terms "comprise," "include," "comprise," or "have" are intended to specify the presence of implemented features, numbers, steps, components, or combinations thereof, and should be understood not to preclude the presence or possible addition of one or more other features, numbers, steps, components, or combinations thereof.

[0020] In this specification, the average particle size (D 50 The average particle size (D) can be defined as the particle size corresponding to 50% of the cumulative volume in the particle size distribution curve. 50 ) can be measured, for example, by the laser diffraction method. The laser diffraction method is generally capable of measuring particle sizes from the submicron range to several mm, and can provide results with high reproducibility and high resolution.

[0021] Negative electrode-free battery The present invention provides a negative electrode-less battery, which may be a negative electrode-less lithium secondary battery.

[0022] Specifically, the anodeless battery according to the present invention includes a positive electrode, a negative electrode facing the positive electrode, a separator and an electrolyte interposed between the positive electrode and the negative electrode, the positive electrode includes a positive electrode active material, and the positive electrode active material includes a lithium transition metal oxide, the negative electrode includes a negative electrode current collector for the anodeless battery, the negative electrode current collector for the anodeless battery includes a metal current collecting substrate, and the metal current collecting substrate includes a space portion at least partially exposed to the outside, and is characterized by satisfying the following mathematical formula 1:

[0023] [Mathematical formula 1] 0.7V≦(n×L×V Li ) / M p ≦2.0V

[0024] In the above mathematical formula 1, V is the volume of the space (unit: ml), n is a value (unitless) calculated by the following mathematical formula 2, L is the loading weight of the positive electrode active material in the positive electrode (unit: g), and V Li is the volume per mole of lithium metal (unit: ml / mol), and M p is the molar mass of the lithium transition metal oxide (unit: g / mol).

[0025] [Mathematical formula 2] n=C H ×M p ×1 / 96485mol / C×3600s / h

[0026] In the above mathematical formula 2, C H is the capacity (unit: Ah / g) of the half cell made from the positive electrode and lithium metal counter electrode, and M p is the molar mass of the lithium transition metal oxide (unit: g / mol), C is the unit of coulomb, s is the unit of second, and h is the unit of hour.

[0027] The anodeless battery according to the present invention includes a positive electrode and a negative electrode. The positive electrode includes a positive electrode active material including a lithium transition metal oxide. The anode uses a current collector for anodeless batteries that does not include anode active materials such as carbon or silicon. The current collector for anodeless batteries includes a metal current collector substrate having a void space at least partially exposed to the outside, and the void space and the lithium volumetric relationship of the lithium transition metal oxide in the positive electrode satisfy the following equation (Equation 1). According to the anodeless battery of the present invention, satisfying the equation (Equation 1) allows lithium to smoothly plate from the positive electrode into the void space of the metal current collector substrate, thereby reducing the expansion of the anode and minimizing the formation of lithium dendrites. As a result, the anodeless battery according to the present invention can suppress the formation of lithium dendrites, ensuring safety, and exhibiting improved energy density, excellent charge / discharge efficiency, and lifespan.

[0028] The non-aqueous negative electrode battery according to the present invention includes a positive electrode, a negative electrode facing the positive electrode, a separator interposed between the positive electrode and the negative electrode, and an electrolyte. Specifically, the non-aqueous negative electrode battery can be manufactured by housing an electrode assembly including the positive electrode, the negative electrode facing the positive electrode, and the separator interposed between the positive electrode and the negative electrode in a battery case and then injecting an electrolyte.

[0029] Positive electrode The positive electrode contains a positive electrode active material.

[0030] The positive electrode active material contains a lithium transition metal oxide.

[0031] The lithium transition metal oxide is a compound capable of reversible intercalation and deintercalation of lithium. Specifically, examples of the lithium transition metal oxide include lithium-manganese-based oxides (such as LiMnO2, LiMn2O4, etc.), lithium-cobalt-based oxides (such as LiCoO2, etc.), lithium-nickel-based oxides (such as LiNiO2, etc.), lithium iron phosphate (such as LiFePO4), lithium-nickel-manganese-based oxides (such as LiNi 1-Y Mn Y O2 (where 0 < Y < 1), LiMn 2-z Ni z O4 (where 0 < Z < 2), etc.), lithium-nickel-cobalt-based oxides (such as LiNi 1-Y1 Co Y1 O2 (where 0 < Y1 < 1), etc.), lithium-manganese-cobalt-based oxides (such as LiCo 1-Y2 Mn Y2 O2 (where 0 < Y2 < 1), LiMn 2-z1 Co z1 O4 (where 0 < Z1 < 2), etc.), lithium-nickel-manganese-cobalt-based oxides (such as Li(Ni p Co q Mn r1 )O2 (where 0 < p < 1, 0 < q < 1, 0 < r1 < 1, p + q + r1 = 1) or Li(Ni p1 Co q1 Mn r2)O4 (where 0 < p1 < 2, 0 < q1 < 2, 0 < r2 < 2, p1 + q1 + r2 = 2), etc.), or lithium-nickel-cobalt-transition metal (M) oxide (e.g., Li(Ni p2 Co q2 Mn r3 M S2 )O2 (where M is selected from the group consisting of Al, Fe, V, Cr, Ti, Ta, Mg, and Mo, and p2, q2, r3, and s2 are the atomic fractions of the respective independent elements, 0 < p2 < 1, 0 < q2 < 1, 0 < r3 < 1, 0 < s2 < 1, and p2 + q2 + r3 + s2 = 1), etc.), and any one or more of these compounds may be included. Among them, in terms of being able to improve the capacity characteristics and stability of the battery, the lithium transition metal oxide is LiCoO2, LiMnO2, LiNiO2, lithium nickel manganese cobalt oxide (e.g., Li(Ni 0.6 Mn 0.2 Co 0.2 )O2, Li(Ni 0.5 Mn 0.3 Co 0.2 )O2, or Li(Ni 0.8 Mn 0.1 Co 0.1 )O2, etc.), or lithium nickel cobalt aluminum oxide (e.g., Li(Ni 0.8 Co 0.15 Al 0.05 )O2, etc.).

[0032] The positive electrode may include a positive electrode current collector and a positive electrode active material layer disposed on at least one side of the positive electrode current collector. At this time, the positive electrode active material layer may contain the aforementioned positive electrode active material.

[0033] The positive electrode active material layer may be disposed on at least one side of the positive electrode current collector, specifically, on one side or both sides of the positive electrode current collector.

[0034] The positive electrode active material layer may contain the positive electrode active material at 80% to 99% by weight.

[0035] The positive electrode active material layer may further contain, in addition to the positive electrode active material, at least one additive selected from the group consisting of a binder and a conductive material.

[0036] The binder is a component that aids in bonding the positive electrode active material to the conductive material and the current collector, and is typically added in an amount of 1 to 30 wt % based on the total weight of the positive electrode active material layer. Examples of such binders include polyvinylidene fluoride, polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, polytetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene-butadiene rubber, fluororubber, and various copolymers.

[0037] The conductive material is not particularly limited as long as it is conductive and does not cause chemical changes in the battery. Examples of such conductive materials include graphite; carbon black, acetylene black, ketjen black, channel black, furnace black, lamp black, and thermal black; conductive fibers such as carbon fiber and metal fiber; metal powders such as fluorocarbon, aluminum, and nickel powder; conductive whiskers such as zinc oxide and potassium titanate; conductive metal oxides such as titanium oxide; and conductive materials such as polyphenylene derivatives. Specific examples of commercially available conductive materials include acetylene black products manufactured by Chevron Chemical Company, Denka Singapore Private Limited, and Gulf Oil Company, as well as Ketjenblack, EC series products (manufactured by Armak Company), Vulcan XC-72 (manufactured by Cabot Company), and Super P (manufactured by Timcal).

[0038] The conductive material may be contained in an amount of 1 to 30% by weight based on the total weight of the positive electrode active material layer.

[0039] The positive electrode active material layer may be prepared by adding a positive electrode active material and, optionally, an additive including a binder and / or a conductive material to a solvent to prepare a positive electrode slurry, and then coating, rolling, and drying the slurry on the positive electrode current collector.

[0040] The solvent may contain an organic solvent such as NMP (N-methyl-2-pyrrolidone), and may be used in an amount that provides a desired viscosity when the positive electrode active material and, optionally, a binder and a conductive material are contained. For example, the solvent may be contained so that the concentration of the solids including the positive electrode active material and, optionally, a binder and a conductive material is 50% by weight to 95% by weight, preferably 70% by weight to 90% by weight.

[0041] negative electrode The negative electrode included in the negative electrodeless battery of the present invention will be described in detail below with reference to the drawings. When assigning reference numerals to components in each drawing, the same reference numerals may be assigned to identical components even if they appear in different drawings. In the description of the present invention, if it is determined that a detailed description of related publicly known configurations or functions would obscure the gist of the present invention, that detailed description may be omitted.

[0042] Specifically, FIG. 1 is a schematic side view of a negative electrode according to one embodiment of the present invention, and FIG. 2 is a schematic perspective view of the negative electrode.

[0043] The negative electrode 10 faces the positive electrode (not shown).

[0044] Referring to FIGS. 1 and 2, the anode 10 includes an anode current collector 100 for an anodeless battery. More specifically, the anode 10 is formed from the anode current collector 100 for an anodeless battery. The anode may not include a separate anode active material layer containing a separate anode active material, such as a carbon-based active material or a silicon-based active material, during fabrication. The anode current collector for an anodeless battery does not include a separate lithium insertion material or lithium metal, and can be assembled with a cathode, a separator, and the like to form an electrode assembly and an anodeless battery. During charging, anodeless batteries including the anode current collector for an anodeless battery may experience lithium ions migrating from the cathode to the anode, and the lithium ions may be electrodeposited on the surface or voids of the metal current collector substrate. The lithium electrodeposited on the anode then migrates back to the cathode, allowing the anodeless battery to be discharged.

[0045] The negative electrode current collector 100 for a negative electrode-less battery includes a metal current collecting substrate 110 .

[0046] There are no particular limitations on the metal current collecting substrate 110, as long as it has high conductivity and does not cause chemical changes in the battery. Specifically, the metal current collecting substrate 110 may include at least one selected from the group consisting of copper, stainless steel, aluminum, nickel, titanium, and an aluminum-cadmium alloy, and may specifically include copper.

[0047] The thickness T of the metal current collecting substrate 110 may be 3 μm to 500 μm, and from the viewpoint of considering both high energy density and mechanical strength, may be specifically 3 μm to 100 μm, more specifically 30 μm to 80 μm.

[0048] The metal current collecting substrate may be used in various forms such as a film, sheet, foil, net, mesh, porous body, foam, nonwoven fabric, etc. Specifically, the metal current collecting substrate may be in the form of a sheet, and more specifically, as shown in Figures 1 and 2, the sheet may be in the form of a sheet having predetermined values ​​of horizontal length L, vertical length W, and thickness T.

[0049] The metal current collecting substrate 110 includes a space 120 at least a portion of which is exposed to the outside.

[0050] At least a portion of the space 120 is exposed to the outside, so that lithium ions that migrate from the positive electrode to the negative electrode during charging of the negative electrode-less battery can be plated in the space.

[0051] A plurality of the spaces may be provided. In this case, the spaces may be spaced apart from one another. Specifically, the spaces may be spaced apart from one another by predetermined distances i1 and i2.

[0052] When there are a plurality of spaces, the volumes of the spaces may be, independently of one another, 0.000025 ml to 0.01 ml, specifically 0.00005 ml to 0.0025 ml, more specifically 0.0005 ml to 0.0015 ml. When the volumes are within this range, lithium ions transferred from the positive electrode can be smoothly dispersed and plated in each of the spaces.

[0053] The volume percentage of the spaces 120 relative to the volume of the metal current collecting substrate 110 may be 20% to 60%, specifically 25% to 55%, and more specifically 32% to 45%. When the volume percentage is within this range, lithium ions can be stably plated into the spaces while maximizing the rigidity of the metal current collecting substrate. When there are multiple spaces 120, the volume percentage of the spaces 120 relative to the volume of the metal current collecting substrate 110 may refer to the percentage of the total volume of the multiple spaces 120 relative to the volume of the metal current collecting substrate 110.

[0054] The shape of the space 120 is not particularly limited. For example, the space may have a shape selected from a concave, cylindrical, and rectangular parallelepiped shape. When there are multiple spaces, the multiple spaces may each independently have a shape selected from a concave, cylindrical, and rectangular parallelepiped shape. When the space 120 has a shape selected from a concave, cylindrical, and rectangular parallelepiped shape, the upper surface of the space may be exposed to the outside. For example, when the space 120 has a rectangular parallelepiped shape as shown in FIGS. 1 and 2, the horizontal length l, vertical length w, and thickness t of the space may be appropriately designed taking into account the relationship in Equation 1, the ratio of the volume of the space to the volume of the metal current collecting substrate, and the like. Alternatively, the space may penetrate the metal current collecting substrate.

[0055] The space 120 may be formed by preparing a sheet-shaped metal current collecting substrate and then using a method such as a pin roller, laser ablation, chemical etching, plating, or mechanical scratching, but is not limited thereto.

[0056] In the negative electrode-less battery according to the present invention, the negative electrode-less battery satisfies the following mathematical formula 1.

[0057] [Mathematical formula 1] 0.7V≦(n×L×V Li ) / M p ≦2.0V

[0058] In the above mathematical formula 1, V is the volume of the space (unit: ml), n is a value (unitless) calculated by the following mathematical formula 2, L is the loading weight of the positive electrode active material in the positive electrode (unit: g), and V Li is the volume per mole of lithium metal (unit: ml / mol), and M p is the molar mass of the lithium transition metal oxide (unit: g / mol).

[0059] [Mathematical formula 2] n=C H ×M p ×1 / 96485mol / C×3600s / h

[0060] In the above mathematical formula 2, C H is the capacity (unit: Ah / g) of the half cell made from the positive electrode and lithium metal counter electrode, and M p is the molar mass of the lithium transition metal oxide (unit: g / mol), C is the unit of coulomb, s is the unit of second, and h is the unit of hour.

[0061] The value n in the above mathematical formula 1 is calculated by mathematical formula 2 and can be understood as the number of electrons transferred per mole of lithium transition metal oxide. Li ) / M p " can be understood to mean the maximum volume of lithium that can be transferred from the positive electrode active material in the positive electrode.

[0062] The above "(n×L×V Li ) / M p When the volume of the space portion V is 0.7 to 2.0 times the volume of the space portion V, the life performance and safety of the negative electrode-less battery can be significantly improved. Li ) / M p If "(n×L×V" is less than 0.7 times the volume V of the space, the ability of lithium plating to concentrate in the space decreases, making it difficult to achieve the object of the present invention of suppressing dendrite formation, which is undesirable. Li ) / M p If " is more than 2.0 times the volume V of the space, the rigidity of the current collector will be too low, which is undesirable in terms of reducing the durability of the electrode and the battery.

[0063] Specifically, the above-mentioned "(n × L × V Li ) / M p" may be 0.75 to 1.60 times, more specifically 0.85 to 1.50 times, and even more specifically 0.9 to 1.3 times the volume V of the void space, in which case the effects of electrodeposition of lithium concentrated in the void space, improvement of life performance, and improvement of durability of the current collector can be further improved. That is, the above-mentioned mathematical formula 1 can be modified to the following mathematical formula 1-1.

[0064] [Mathematical formula 1-1] 0.75V≦(n×L×V Li ) / M p ≦1.60V

[0065] When there are a plurality of spaces, the volume V of the space in Equation 1 may represent the sum of the volumes of the plurality of spaces.

[0066] Hereinafter, a negative electrode according to another embodiment of the present invention will be described with reference to Fig. 3. Fig. 3 is a schematic side view for explaining a negative electrode according to another embodiment of the present invention.

[0067] 3, the negative electrode current collector 100 for a negative electrode battery may further include a polymer coating layer 130 disposed on at least one surface of the metal current collecting substrate 110. The polymer coating layer 130 is disposed on the metal current collecting substrate 110 and can effectively prevent expansion of a lithium metal layer that may be disposed on the surface or in a space of the metal current collecting substrate 110, or can effectively suppress the formation of lithium dendrites. In particular, when the polymer coating layer 130 is included in the negative electrode current collector 100 for a negative electrode battery, the effects of improving the life performance and safety of the negative electrode battery according to the relationship in Equation 1 can be more effectively achieved.

[0068] The polymer coating layer 130 may be located on at least one side of the metal current collecting substrate 110, specifically on one or both sides of the metal current collecting substrate.

[0069] The polymer coating layer 130 may be disposed to face the separator (not shown). Specifically, the polymer coating layer 130 may be disposed on the upper surface of the negative electrode current collector for the negative electrode-less battery.

[0070] The polymer coating layer 130 may include at least one polymer selected from the group consisting of an acrylic polymer, polyurethane, polyurea, polyvinyl chloride, polyethylene oxide, polyacrylamide, polyacrylonitrile, polysaccharide, PEDOT:PSS, styrene-butadiene rubber, polyimide, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyvinylidene fluoride-chlorotrifluoroethylene copolymer, carboxymethyl cellulose, methyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, polypyrrole, and polystyrene. Preferably, the polymer coating layer may include at least one polymer selected from the group consisting of polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, and polyvinylidene fluoride-chlorotrifluoroethylene copolymer, from the viewpoints of excellent electrolyte impregnation, high ionic conductivity, stable electrodeposition of lithium ions onto the metal current collecting substrate, and suppression of lithium dendrite growth.

[0071] The polymer coating layer 130 may further contain at least one additive selected from the group consisting of a lithium compound and a porous filler, in addition to the polymer.

[0072] The lithium compound may contribute to the formation of a solid electrolyte interface layer (SEI layer) on the surface of the negative electrode current collector during initial charging, thereby further improving the ionic conductivity of the coating layer and contributing to improved life performance.

[0073] The lithium compound may include at least one selected from the group consisting of a lithium salt and a lithium ion conductor, and more specifically, may include a lithium salt.

[0074] The lithium salt may include at least one selected from the group consisting of LiCl, LiBr, LiI, LiNO3, LiClO4, LiBF4, LiB 10 Cl 10 , LiPF6, LiCF3SO3, LiCF3CO2, LiAsF6, LiSbF6, LiAlCl4, CH3SO3Li, CF3SO3Li, LiSCN, LiC(CF3SO2)3, (CF3SO2)2NLi, (FSO2)2NLi, Li3BO3, Li2B4O7, and LiBO2. More specifically, by increasing the content of inorganic substances such as Li3N and Li2O on the surface of the negative electrode current collector, promoting the formation of a stable SEI layer, and inducing the surface shape of the plated lithium metal to be spherical during charging, the formation of lithium dendritic crystals can be suppressed. Therefore, it may include LiNO3.

[0075] The lithium ion conductor may include at least one selected from the group consisting of an oxide-based lithium ion conductor, a phosphate-based lithium ion conductor, a nitride-based lithium ion conductor, and a sulfide-based lithium ion conductor.

[0076] The oxide-based lithium ion conductor includes LLZO-based compounds (Li-La-Zr-O-based compounds, such as Li7La3Zr2O 12 ), LLZTO-based compounds (Li-La-Zr-Ta-O-based compounds, such as Li 6.4 La3Zr 1.4 Ta 0.6 O 12 ), LLTO-based compounds (Li-La-Ti-O-based compounds, such as a compound represented by the chemical formula Li 3p La 2 / 3-p TiO3, where 0 < p < 0.16), and LISICON (Lithium super ionic conductor, such as Li 2+w Zn1-w A compound represented by the chemical formula GeO4, where w may include at least one selected from the group consisting of 0 < w ≦ 1).

[0077] The phosphate-based lithium ion conductor is an LZPO-based compound (Li-Zr-P-O-based compound, such as LiZr2(PO4)3), an LZSP-based compound (Li-Zr-Si-P-O-based compound, such as Li3Zr2Si2PO 12 ), an LTPO-based compound (Li-Ti-P-O-based compound, such as LiTi2(PO4)3), and LATP (Li-Al-Ti-P-O-based compound, such as Li 1+q Al q Ti 2-q (PO4)3), and may include at least one selected from the group consisting of 0.3 ≦ q ≦ 0.5).

[0078] The nitride-based lithium ion conductor may include at least one selected from the group consisting of LiPON (lithium phosphorous oxynitride), Li3N, and Li3AlN2.

[0079] The sulfide-based lithium ion conductor may be at least one selected from the group consisting of Li2S-P2S5, Li3PS4, an LGPS-based compound (Li-Ge-P-S-based compound, such as Li 10 GeP2S 12 ), and Thio-LISICON (a material in which a part of the oxygen in LISICON is substituted by sulfur).

[0080] When the polymer coating layer 130 contains a lithium compound, the lithium compound may be contained in the polymer coating layer in an amount of 1 wt % to 90 wt %, more specifically 5 wt % to 50 wt %, even more specifically 10 wt % to 40 wt %, and even more specifically 20 wt % to 35 wt %. This range is preferable from the viewpoints of achieving the effects of forming a stable SEI layer and preventing the formation of lithium dendrites, effectively compensating for the concentration gradient caused by the depletion of lithium ions on the surface of the negative electrode current collector during charge and discharge, and preventing an increase in resistance when an excessive amount of lithium compound is added. In this case, the polymer may be contained in the polymer coating layer in an amount remaining after excluding the content of the lithium compound.

[0081] The porous filler may be included to complement the impregnation of the coating layer with the electrolyte and to improve the ionic conductivity and mechanical strength.

[0082] The porous filler may include at least one selected from the group consisting of activated carbon, diatomaceous earth, fumed silica, silica, silica gel, precipitated silica, calcium carbonate, alumina, zeolite, talc, bohemite, and mica, and may specifically include silica. The silica may be, for example, lithium-modified mesoporous silica.

[0083] The average particle size (D 50 The average particle diameter (D) of the porous filler may be 1 nm to 5,000 nm, specifically 5 nm to 1,000 nm, and more specifically 250 nm to 600 nm. 50 ) is in the above range, the ionic conductivity of the coating layer is further improved, and this is preferable from the viewpoint of ensuring uniformity of the slurry of the coating layer-forming composition used in producing the coating layer.

[0084] The BET specific surface area of ​​the porous filler is 10 m2 / g~1,500m 2 / g, specifically 100m 2 / g~600m 2 / g, and when it is in the above range, it is preferable from the viewpoint that the impregnation of the electrolyte solution is further improved and the uniformity of the coating layer is ensured.

[0085] The BET specific surface area is measured by the BET method, and specifically, may be calculated by determining the amount of nitrogen gas adsorbed at the temperature of liquid nitrogen (77K) using a BELSORP-mini II manufactured by BEL Japan.

[0086] When the polymer coating layer 130 includes a porous filler, the porous filler may be included in the polymer coating layer in an amount of 1 wt % to 90 wt %, more specifically 3 wt % to 50 wt %, and even more specifically 5 wt % to 30 wt %. This range is preferable in terms of further improving the electrolyte impregnation of the coating layer, improving ionic conductivity, and further improving the uniformity of the coating layer. In this case, the polymer in the polymer coating layer may be included in the remaining amount excluding the content of the porous filler.

[0087] The thickness of the polymer coating layer 130 may be 0.1 μm to 150 μm, specifically 0.5 μm to 50 μm, more specifically 1 μm to 20 μm, still more specifically 2 μm to 10 μm, and even more specifically 2 μm to 5 μm. When the thickness is within this range, the application of the coating layer can achieve the effect of suppressing the formation of lithium dendrites, and the volume of the negative electrode current collector including the coating layer can be reduced, which is preferable from the viewpoint of improving the energy density of the secondary battery.

[0088] The polymer coating layer 130 may be prepared by applying a composition for forming a polymer coating layer, which includes a coating polymer and, optionally, a lithium compound and / or a porous filler, to the metal current collecting substrate and drying the composition.

[0089] The drying temperature during the drying can be adjusted appropriately depending on the type of polymer, and may be, for example, 95° C. or lower, more specifically 30° C. to 75° C., and even more specifically 40° C. to 65° C. In this case, the drying time may be 1 hour to 5 hours.

[0090] The drying may be carried out, for example, under vacuum conditions.

[0091] After the drying, the temperature may be lowered to room temperature (specifically, 20° C. to 25° C.) and then further dried. The further drying may be carried out for, for example, 1 hour to 100 hours, specifically 24 hours to 80 hours.

[0092] Separator The separator separates the negative electrode and the positive electrode and provides a path for lithium ions to move. Any separator commonly used in lithium secondary batteries can be used without limitation. In particular, a separator with low resistance to ion movement and excellent humidifying ability for the electrolyte is preferred. Specifically, a porous polymer film, such as a porous polymer film made of a polyolefin polymer, such as an ethylene homopolymer, a propylene homopolymer, an ethylene / butene copolymer, an ethylene / hexene copolymer, or an ethylene / methacrylate copolymer, or a laminate structure of two or more layers thereof, can be used. Conventional porous nonwoven fabrics, such as nonwoven fabrics made of high-melting-point glass fibers or polyethylene terephthalate fibers, can also be used. To ensure heat resistance or mechanical strength, a separator coated with a ceramic component or a polymer material can be used, and it can be selectively used in a single-layer or multi-layer structure.

[0093] electrolyte Furthermore, examples of the electrolyte used in the present invention include organic liquid electrolytes, inorganic liquid electrolytes, solid polymer electrolytes, gel-type polymer electrolytes, solid inorganic electrolytes, and molten inorganic electrolytes that can be used in the production of lithium secondary batteries, but are not limited to these.

[0094] Specifically, the electrolyte may include an organic solvent and a lithium salt.

[0095] The organic solvent can be any solvent capable of transporting ions involved in the electrochemical reaction of the battery. Examples of suitable organic solvents include ester solvents such as methyl acetate, ethyl acetate, gamma-butyrolactone, and ε-caprolactone; ether solvents such as dibutyl ether and tetrahydrofuran; ketone solvents such as cyclohexanone; aromatic hydrocarbon solvents such as benzene and fluorobenzene; carbonate solvents such as dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), ethylene carbonate (EC), and propylene carbonate (PC); alcohol solvents such as ethyl alcohol and isopropyl alcohol; nitriles such as R-CN (where R is a C2-C20 linear, branched, or cyclic hydrocarbon group that may contain a double-bonded aromatic ring or an ether bond); amides such as dimethylformamide; dioxolanes such as 1,3-dioxolane; and sulfolanes. Among these, carbonate-based solvents are preferred, and a mixture of a cyclic carbonate (e.g., ethylene carbonate or propylene carbonate) with high ionic conductivity and high dielectric constant, which can improve the charge / discharge performance of the battery, and a low-viscosity linear carbonate compound (e.g., ethyl methyl carbonate, dimethyl carbonate, or diethyl carbonate) is more preferred. In this case, it is preferable to mix the cyclic carbonate and the linear carbonate in a volume ratio of about 1:1 to about 1:9, from the viewpoint of excellent performance of the electrolyte solution.

[0096] The lithium salt can be any compound capable of providing lithium ions used in lithium secondary batteries. Specifically, the lithium salt may be LiPF, LiClO, LiAsF, LiBF, LiSbF, LiAlO, LiAlCl, LiCF, SO, LiCF, SO, LiN(C, F, SO), LiN(C, F, SO), LiN(CF, SO), LiCl, LiI, or LiB(C, O) . The lithium salt concentration is preferably 0.1 to 7 M, more preferably 0.8 to 3.0 M. When the lithium salt concentration is within this range, the electrolyte has appropriate conductivity and viscosity, resulting in excellent electrolyte performance and efficient lithium ion migration.

[0097] As described above, the anodeless battery according to the present invention is useful in fields such as mobile phones, laptops, digital cameras, and other portable devices, and electric vehicles such as hybrid electric vehicles (HEVs), and is particularly suitable for use as a battery constituting a medium- to large-sized battery module. Accordingly, the present invention also provides a medium- to large-sized battery module including the above-described anodeless battery as a unit cell.

[0098] Such a medium- to large-sized battery module can be suitably applied to power sources that require high output and large capacity, such as electric vehicles, hybrid electric vehicles, and power storage devices.

[0099] The present invention will be described in detail below with reference to exemplary embodiments so that those skilled in the art can easily understand the present invention. However, the present invention may be embodied in many different forms and is not limited to the exemplary embodiments set forth herein.

[0100] Examples and Comparative Examples Example 1: Fabrication of a negative electrode-less battery (1) Manufacturing of negative electrode current collectors for non-negative electrode batteries A sheet of copper foil was prepared as a metal current collecting substrate (width x length x thickness: 34 mm x 51 mm x 50 μm, volume: 0.087 ml).

[0101] A pin roller was used to form a plurality of spaces in the copper foil. Each of the spaces was a rectangular parallelepiped, measuring 6 mm x 6 mm x 25 μm in width, height, and thickness (volume of each space: 0.0009 ml). The spaces were patterned to be spaced apart from each other at intervals of 0.5 mm in the horizontal direction and 1 mm in the vertical direction. The total volume of the spaces (V in Equation 1) was 0.031 ml. The percentage of the total volume of the spaces relative to the volume of the metal current collecting substrate was 35.6% by volume.

[0102] Next, a polymer coating layer was formed on the metal current collecting substrate. A polymer coating composition (solids content: 10 wt%) was prepared by dispersing PVDF as the polymer and LiNO3 as the lithium salt in N-methylpyrrolidone (NMP) solvent. The polymer coating composition was applied to the metal current collecting substrate and dried at 60°C for 2 hours under vacuum conditions (approximately -0.1 MPa). The temperature was then gradually lowered to room temperature and the substrate was further dried for 70 hours to form a polymer coating layer (thickness: 2.5 μm). The polymer coating layer contained 66.7 wt% of the polymer and 33.3 wt% of the lithium salt.

[0103] The metal current collecting substrate on which the polymer coating layer was formed was used as a negative electrode current collector for a negative electrode-less battery.

[0104] (2) Manufacturing of the positive electrode A positive electrode slurry was produced by mixing LiCoO2 as the positive electrode active material, carbon black as the conductive material, and PVDF as the binder in a weight ratio of 96:2:2 in N-methylpyrrolidone solvent. This slurry was then applied to an aluminum current collector (width x length x thickness: 33 mm x 50 mm x 15 μm), dried, and rolled to form a positive electrode active material layer, which served as the positive electrode.

[0105] The positive electrode active material layer has a thickness of 23 mg / cm 2At this time, the loading weight of LiCoO2 (L in Equation 1) was 0.3795 g.

[0106] (3) Manufacturing of anode-less batteries An electrode assembly including the positive electrode, the negative electrode current collector for the negative electrode battery, and a polyethylene separator interposed between the positive electrode and the negative electrode current collector for the negative electrode battery was manufactured, and the assembly was then housed in a battery case, after which an electrolyte was injected and the battery was sealed to prepare a negative electrode battery.

[0107] The electrolyte used here was a mixture of ethylene carbonate (EC) and ethyl methyl carbonate (EMC) as organic solvents in a volume ratio of 2:8, vinylene carbonate (VC) as an additive at 0.5 wt% relative to the total weight of the electrolyte, and LiPF6 as a lithium salt at a concentration of 1.2 mol / L.

[0108] (4) Whether mathematical formula 1 is satisfied or not 1) Mathematical formula 1 [Mathematical formula 1] 0.7V≦(n×L×V Li ) / M p ≦2.0V In the above mathematical formula 1, V is the volume of the space (unit: ml), n is a value (unitless) calculated by the following mathematical formula 2, L is the loading weight of the positive electrode active material in the positive electrode (unit: g), and V Li is the volume per mole of lithium metal (unit: ml / mol), and M p is the molar mass of the lithium transition metal oxide (unit: g / mol), [Mathematical formula 2] n=C H ×M p ×1 / 96485mol / C×3600s / h In the above mathematical formula 2, C H is the capacity (unit: Ah / g) of the half cell made from the positive electrode and lithium metal counter electrode, and M pis the molar mass of the lithium transition metal oxide (unit: g / mol), C is the unit of coulomb, s is the unit of second, and h is the unit of hour.

[0109] 2) Calculation of n C H To determine the capacity (C), an electrode assembly was fabricated by interposing a polyethylene separator between the cathode and lithium metal counter electrode, and then housed in a battery case. An electrolyte was then injected and sealed to fabricate a half-cell. The electrolyte used was an organic solvent mixture of ethylene carbonate (EC), dimethyl carbonate (DMC), and ethyl methyl carbonate (EMC) in a volume ratio of 30:40:30, to which LiPF6 was added at a concentration of 1M. The half-cell was charged and discharged five times to measure the capacity (C) of the half-cell. H :0.2Ah / g).

[0110] The charge and discharge conditions for the half cell were as follows: -Charging conditions: CC / CV, 0.1C charging, 4.5V, 1 / 20C Cut-off -Discharge conditions: CC, 0.1C discharge, 3.0V Cut-off

[0111] The C obtained above H , M p and the molar mass of LiCoO2, 97.9 g / mol, were substituted into the above mathematical formula 2 to obtain n (=0.73).

[0112] 3)(n×L×V Li ) / M p V Li was calculated by dividing the density of lithium metal, 0.534 g / ml, by the molar mass of lithium metal, 6.94 g / mol (V Li =0.077 ml / mol).

[0113] This calculated (n×L×V Li ) / M p The value of is 0.0375.

[0114] 4) Therefore, in the negative electrode current collector for the negative electrode-less battery of Example 1, (n × L × V Li ) / M p is calculated to be 1.21 times V, which satisfies the relationship of Mathematical Formula 1.

[0115] Example 2: Production of a negative electrode current collector for a negative electrode-less battery A negative electrode-less battery was manufactured in the same manner as in Example 1, except that each of the multiple spaces was patterned into a rectangular parallelepiped shape with a width x length x thickness of 6 mm x 6 mm x 20 μm (volume of each space: 0.00072 ml).

[0116] The percentage of the volume of the space with respect to the volume of the metal current collecting substrate was 28.7% by volume, and the total volume of the space (V in Equation 1) was 0.025 ml.

[0117] In the negative electrode current collector for the negative electrode-less battery of Example 2, (n × L × V Li ) / M p is calculated to be 1.50 times V, and satisfies the relationship of the above mathematical formula 1.

[0118] Example 3: Production of negative electrode current collector for negative electrode-less battery A negative electrode-less battery was manufactured in the same manner as in Example 1, except that each of the multiple spaces was patterned into a rectangular parallelepiped shape with a width x height x thickness of 6 mm x 6 mm x 30 μm (volume of each space: 0.00108 ml).

[0119] The percentage of the volume of the space with respect to the volume of the metal current collecting substrate was 50.6% by volume, and the total volume of the space (V in Equation 1) was 0.044 ml.

[0120] In the negative electrode current collector for the negative electrode-less battery of Example 3, (n × L × V Li ) / M p is calculated to be 0.85 times V, and satisfies the relationship of Mathematical Formula 1 above.

[0121] Comparative Example 1: Production of a negative electrode current collector for a non-negative electrode battery A negative electrode-less battery was manufactured in the same manner as in Example 1, except that each of the multiple spaces was patterned into a rectangular parallelepiped shape with a width x length x thickness of 6 mm x 6 mm x 10 μm (volume of each space: 0.00036 ml).

[0122] In this case, the percentage of the volume of the space with respect to the volume of the metal current collecting substrate was 14.9% by volume, and the total volume of the space (V in Equation 1) was 0.013 ml.

[0123] In the negative electrode current collector for the negative electrode-less battery of Comparative Example 1, (n×L×V Li ) / M p is calculated to be 2.88 times V, which does not satisfy the relationship of Mathematical Formula 1.

[0124] Comparative Example 2: Production of a negative electrode current collector for a non-negative electrode battery A negative electrode-less battery was manufactured in the same manner as in Example 1, except that each of the multiple spaces was patterned into a rectangular parallelepiped shape with a width x height x thickness of 6 mm x 6 mm x 45 μm (volume of each space: 0.00162 ml).

[0125] The percentage of the volume of the space with respect to the volume of the metal current collecting substrate was 65.5% by volume, and the total volume of the space (V in Equation 1) was 0.057 ml.

[0126] In the negative electrode current collector for the negative electrode-less battery of Comparative Example 2, (n×L×V Li ) / M p is calculated to be 0.66 times V, which does not satisfy the relationship of mathematical formula 1.

[0127] Experimental example Experimental example 1: Evaluation of charge / discharge efficiency The negative electrode-free batteries of the Examples and Comparative Examples prepared above were cycle-charged and discharged at 25° C. under the following conditions to evaluate the capacity retention rate. A graph of the capacity retention rate over cycles is shown in FIG. 1, and the capacity retention rate after 10 cycles is shown in Table 1 below.

[0128] The capacity retention rate was evaluated according to the following formula. Capacity retention rate (%) = {(discharge capacity of the battery without a negative electrode in N cycles) / (discharge capacity of the battery without a negative electrode in the first cycle)} × 100 (In the above formula, N is an integer of 1 or more.) *Charging and discharging conditions Charging: CC / CV mode; 0.1C; 4.5V, 1 / 20C cut-off Discharge: CC mode; 0.1C; 3.0V cut-off

[0129] [Table 1]

[0130] Referring to Table 1, it can be seen that the negative electrode-free batteries according to Examples 1 to 3 exhibit superior levels of charge / discharge efficiency and life performance compared to the negative electrode-free batteries according to Comparative Examples 1 and 2. [Explanation of symbols]

[0131] 10 negative electrode 100 Negative current collector for negative electrode batteries 110 Metal current collecting substrate L: Horizontal length of the metal current collector substrate W: Vertical length of the metal current collector substrate T is the thickness of the metal current collector substrate 120 Space section l Horizontal length of the space w Vertical length of the space t Thickness of the space i1, i2: Distance between the spaces 130 Polymer coating layer

Claims

1. a positive electrode, a negative electrode facing the positive electrode, a separator and an electrolyte interposed between the positive electrode and the negative electrode, the positive electrode includes a positive electrode active material, the positive electrode active material includes a lithium transition metal oxide, the negative electrode includes a negative electrode current collector for a negative electrode-less battery, The negative electrode current collector for the negative electrode-less battery includes a metal current collecting substrate, the metal current collecting substrate includes a space portion at least a portion of which is exposed to the outside, A negative electrode-less battery that satisfies the following mathematical formula 1: [Mathematical formula 1] 0.7V≦(n×L×V Ｌｉ ) / M ｐ ≦2.0V (In the above mathematical formula 1, V is the volume of the space (unit: ml), n is a value (unitless) calculated by the following mathematical formula 2, L is the loading weight of the positive electrode active material in the positive electrode (unit: g), and V Ｌｉ is the volume per mole of lithium metal (unit: ml / mol), and M ｐ is the molar mass of the lithium transition metal oxide (unit: g / mol). [Mathematical formula 2] n=C Ｈ ×M ｐ ×1 / 96485mol / C×3600s / h (In the above mathematical formula 2, C Ｈ is the capacity (unit: Ah / g) of a half cell made from the positive electrode and a lithium metal counter electrode, and M ｐ is the molar mass of the lithium transition metal oxide (unit: g / mol), C is the unit of coulomb, s is the unit of second, and h is the unit of hour.

2. 2. The negative electrodeless battery according to claim 1, wherein the percentage of the volume of the space relative to the volume of the metal current collecting substrate is 20% to 60%.

3. The negative electrodeless battery according to claim 1 , wherein the space has at least one shape selected from the group consisting of a recess, a cylindrical shape, and a rectangular parallelepiped shape.

4. The space portion is provided in plurality, The negative electrodeless battery according to claim 1 , wherein the plurality of spaces are spaced apart from one another.

5. 5. The negative electrodeless battery according to claim 4, wherein the volume of each of the plurality of spaces is, independently of one another, 0.000025 ml to 0.01 ml.

6. 2. The negative electrode-less battery according to claim 1, wherein the thickness of the metal current collecting substrate is 3 μm to 100 μm.

7. 10. The anodeless battery of claim 1, wherein the metal current collecting substrate comprises copper.

8. The anodeless battery according to claim 1 , wherein the anode current collector for the anodeless battery further comprises a polymer coating layer disposed on at least one surface of the metal current collecting substrate.

9. The negative electrodeless battery of claim 8 , wherein the polymer coating layer is disposed opposite the separator.

10. 9. The negative electrodeless battery of claim 8, wherein the polymer coating layer comprises at least one polymer selected from acrylic polymers, polyurethane, polyurea, polyvinyl chloride, polyethylene oxide, polyacrylamide, polyacrylonitrile, polysaccharides, PEDOT:PSS, styrene-butadiene rubber, polyimide, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyvinylidene fluoride-chlorotrifluoroethylene copolymer, carboxymethyl cellulose, methyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, polypyrrole, and polystyrene.

11. 9. The negative electrode-less battery according to claim 8, wherein the polymer coating layer has a thickness of 0.1 μm to 150 μm.

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