WO2018169337A1

WO2018169337A1 - Structure

Info

Publication number: WO2018169337A1
Application number: PCT/KR2018/003077
Authority: WO
Inventors: 박은경; 최장욱; 김병곤; 장민철; 손병국; 최정훈; 강동현
Original assignee: 주식회사 엘지화학; 한국과학기술원
Priority date: 2017-03-16
Filing date: 2018-03-16
Publication date: 2018-09-20

Abstract

The present invention relates to a structure. More particularly, a tube-shaped structure, one side surface of which is open, or both side surfaces of which are open, is manufactured, and an electrode active material, such as lithium metal, is then formed around a metal included in the inner surface of the tube, thereby preventing formation of lithium metal dendrites and reaction between the lithium metal and the electrolyte.

Description

Structure

This application claims the benefit of priority based on Korean Patent Application No. 10-2017-0033414 dated March 16, 2017 and Korean Patent Application No. 10-2018-0030410 dated March 15, 2018. All content disclosed in the literature is included as part of this specification.

The present invention relates to a structure that can be used for supporting an electrode active material.

Recently, the development of the electronic industry enables the miniaturization and lightening of electronic equipment, and thus the use of portable electronic devices is increasing. The need for a secondary battery having a high energy density as a power source for such a portable electronic device has been increasing, and research on lithium secondary batteries has been actively conducted. In addition, lithium ion batteries, which are being applied as batteries for electric vehicles, have been employed in short-haul vehicles due to physical limitations (maximum energy density of 250 Wh / kg).

Lithium metal is an ideal material for cathodes of high energy density lithium secondary batteries with a high theoretical capacity of 3862 mAh / g and a low standard electrode potential (-3.04 vs SHE). However, due to safety problems due to internal short circuit of the battery due to lithium dendrite growth, it has not been commercialized as a negative electrode material of a lithium battery. In addition, lithium metal may adversely react with the active material or the electrolyte, which may greatly affect the short circuit and the life of the battery. Therefore, stabilization and dendrite suppression technology of lithium metal electrode is a core technology that must be preceded for the development of the next-generation lithium secondary battery.

In order to prevent the growth of the lithium metal dendrites and the reaction of the lithium metal and the electrolyte, research on various types of electrode active materials has been continued.

For example, Au is deposited on the inner surface of the hollow capsule, and a cathode active material in which lithium metal is filled in the hollow capsule has been developed using the Au as a seed (Yan, et al ., Nature Energy 1 , Article number: 16010 (2016), "Selective deposition and stable encapsulation of lithium through heterogeneous seeded growth"). The hollow active material of the hollow capsule form can secure stability in the electrolyte due to the sealed shape, but it is not easy to control the volume of the lithium metal to be filled in the hollow capsule, the electrode configuration due to the spherical shape There is a problem that the electrical conductivity may be reduced.

Accordingly, there is a need to develop an active material in which lithium metal dendrites can be prevented from forming and the reaction between the lithium metal and the electrolyte can be prevented, and the amount of the electrode active material can be easily adjusted according to the capacity of the battery.

[Preceding technical literature]

[Patent Documents]

(Patent Document 1) Republic of Korea Patent No. 1155909, "Negative active material for lithium secondary battery, a manufacturing method thereof and a lithium secondary battery comprising the same"

[Non-Patent Documents]

(Non-Patent Document 1) Yan, et al ., Nature Energy 1, Article number: 16010 (2016), "Selectve deposition and stable encapsulation of lithium through heterogeneous seeded growth"

The inventors have conducted various studies to solve the above problems. As a structure capable of supporting the electrode active material, the present invention forms a tube having one or both sides with an open shape, and the electrode active material is formed on the inner surface of the tube. A structure was formed to form a highly reactive metal. Such a structure can prevent a phenomenon in which an electrode active material supported therein grows in a dendrite shape, and prevents a reaction between the electrode active material and an electrolyte solution to improve battery stability. It was confirmed that it could be improved.

Accordingly, it is an object of the present invention to provide a structure having a shape capable of supporting an electrode active material to improve battery safety.

The present invention to achieve the above object, one side or both sides open the tube; And a metal included in the inner surface of the tube.

In this case, the aspect ratio (a) of the tube longitudinal section included in the structure is calculated by the following Equation 1, it may be greater than one.

[Equation 1]

a = L / D _ex

In Equation 1, L is the length of the tube, D _ex is the outer diameter of the tube.

The invention also provides a tube that is open on one side or both sides; A metal contained in the inner surface of the tube; And a lithium metal formed on the metal.

According to the structure according to the present invention, due to the metal on the inner surface of the tube included in the structure, it is possible to prevent the electrode active material is formed around the metal to grow in the form of dendrites, and also to prevent the reaction with the electrolyte solution The safety of the battery can be improved.

Specifically, the structure may be used as a negative electrode active material in which lithium metal is supported.

In addition, the tube-shaped structure is one side or both sides open form, there is a more advantageous effect in that it is possible to secure the electrically conductive path.

In addition, the structure is a tube-shaped structure having an aspect ratio of more than 1, the tube shape itself having an aspect ratio of more than 1 may be a path of electrical conduction.

1A and 1B are schematic views of a structure according to an embodiment of the present invention (FIG. 1A: before supporting lithium metal as a structure, and FIG. 1B: after supporting lithium metal as a structure).

2A and 2B are schematic views showing longitudinal and transverse cross sections of a tube in a structure according to one embodiment of the invention, respectively.

3 is a schematic view of a dual-nozzle system as an electrospinning apparatus used for manufacturing a structure according to an embodiment of the present invention.

4A to 4C are graphs showing the results of charge and discharge experiments on lithium half cells manufactured using the structures of Examples and Comparative Examples of the present invention.

5 is a transmission electron microscopy (TEM) photograph of the lithium half battery manufactured using the structure of Example 1 before and after charging and discharging (Pristine: before charge and discharge, 20 ^th D: after the 20th discharge, 20 ^th C: after 20th charge).

FIG. 6 is a scanning electron microscope (SEM) photograph of a growth pattern of lithium metal when charging a lithium half battery manufactured using the structures of Examples and Comparative Examples. FIG.

Hereinafter, the present invention will be described in more detail to aid in understanding the present invention.

The terms or words used in this specification and claims are not to be construed as limiting in their usual or dictionary meanings, and the inventors may appropriately define the concepts of terms in order to best describe their invention. It should be interpreted as meaning and concept corresponding to the technical idea of the present invention based on the principle that the present invention.

구조체 (1)Structure (1)

The present invention relates to a structure capable of supporting an electrode active material. For example, when the structure supports lithium metal as a negative electrode active material, the growth of lithium metal in a dendrite form in a negative electrode of a lithium metal battery is disclosed. The present invention relates to a structure capable of preventing the lithium metal and the electrolyte from directly reacting at the same time.

Hereinafter, the present invention will be described in more detail with reference to the drawings.

1A and 1B are schematic views of a structure according to an embodiment of the present invention.

Referring to FIG. 1A, the structure 10 includes a tube 11 having both sides open; And a metal 13 formed on the inner surface of the tube 11. The tube 11 illustrates a form in which both sides are open, but one side may be in an open form.

2A and 2B, the aspect ratio a of the tube 11 longitudinal section may be greater than one.

At this time, the aspect ratio of the tube 11 longitudinal section may be calculated by the following equation (1).

[Equation 1]

a = L / D _ex

Where L is the length of the tube 11 and D _ex is the outer diameter of the tube 11.

For example, the length L of the tube 11 may be 2 μm to 25 μm, preferably 3 μm to 15 μm, more preferably 4 μm to 10 μm. If it is less than the above range it may be difficult to implement a tube having an aspect ratio of 1 or more by Equation 1, if the above range is low packing density (packing density) is a problem that the gap of the electrode even after rolling, the energy density per cell volume lowers There can be.

The outer diameter D _ex of the tube 11 may be 0.2 μm to 2 μm, preferably 0.3 μm to 1.2 μm, more preferably 0.5 μm to 1 μm. If it is less than the above range, the lithium metal 14 contained in the structure 10 is reduced in volume, thereby reducing lithium dendrite suppression and battery cycle life, lowering the specific capacity of the active material and the energy density per weight of the battery. If it is exceeded, it is difficult to maintain the tube shape during the manufacturing process, and the tube shape collapses during the electrode manufacturing and rolling processes, thereby lowering the lithium dendrite suppressing effect.

The actual size of the tube 11, such as length L, outer diameter D _ex and inner diameter D _in, can be measured with a scanning electron microscope (SEM) or transmission electron microscope (TEM).

The structure 10 has the shape of a tube 11 having an aspect ratio greater than 1 (a> 1) as described above, and the tube 11 includes a carbon-based polymer, so that the structure 10 itself is an electrically conductive path. Can function as

In addition, the tube 11 has a cylindrical shape with both sides open, and may itself be an electric conduction path and improve ion conductivity by electrolyte wetting.

On the other hand, if the structure is a sphere-shaped hollow capsule, due to the closed shape is difficult to impregnate the electrolyte compared to the open tube form, it is difficult to transfer lithium ions to the inside of the structure and to control the volume of the lithium metal filled inside Not easy to do, due to the spherical shape there is a problem that the electrical conductivity can be reduced when configuring the electrode.

The shell of the tube 11 may exhibit electrical conductivity and may also exhibit lithium ion conductivity.

In this case, the shell of the tube 11 may include carbon, and the carbon may be amorphous carbon.

In addition, the tube 11, specifically, the shell of the tube 11 may be porous, in this case, when the outer diameter of the tube is large, the thickness of the shell must be thickened to increase the strength, in which case the shell has pores In this case, the electrolyte can penetrate to the inside of the shell, thereby reducing the battery resistance. The pore size may have a size of 2 nm to 200 nm and the porosity is preferably maintained at a value of 0% to 50% to maintain the strength of the tube.

On the other hand, the metal 13 may be included in the form formed on the inner surface of the tube 11, the metal 13 based on the total weight of the structure 10, that is, the tube 11 and the metal 13 is 0.1 To 25% by weight, preferably 0.1 to 15% by weight, more preferably 0.5 to 10% by weight.

If the weight of the metal 13 is less than the above range, the site to which the electrode active material may bind may not be sufficient. If the weight of the metal 13 is greater than the above range, the amount of the metal 13 may be excessive so that the amount of the electrode active material may be filled. As a result, the specific capacity of the electrode active material may be reduced.

The metal 13 may be formed on the inner surface of the tube 11 in the form of particles, the particle diameter of the metal 13 is 1 to 50 nm, preferably 5 to 40 nm, more preferably 10 to 30 nm Can be. If the area is less than the above range, the electrode active material may not be bonded enough to induce smooth growth of the electrode active material. If the area is more than the above range, the area of the metal 13 may be increased, thereby reducing the specific amount of the electrode active material.

In the present invention, the tube 11 may be for supporting the electrode active material.

The electrode active material may be a positive electrode active material or a negative electrode active material that is commonly used.

The positive electrode active material may be an oxide composed of lithium and a transition metal having a structure capable of intercalating lithium, and for example, may be represented by the following Chemical Formula 1.

[Formula 1]

Li _a Ni _1-xy Co _x Mn _y M _b O ₂

In Formula 1, a = 1, 0.1 ≦ x ≦ 0.3, 0.15 ≦ y ≦ 0.25, 0 ≦ b ≦ 0.05, and M is Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, Zn and It may be any one selected from a transition metal or a lanthanide element selected from the group consisting of a combination thereof.

Examples of the negative electrode active material include amorphous carbon such as graphite carbon, non-graphitized carbon, crystalline carbon, and the like. Other LixFe ₂ O ₃ (0 ≦ x ≦ 1) and LixWO ₂ (0 ≦ x ≦ 1 ), Sn _x Me ₁ _- _x Me ' _y O _z (Me: Mn, Fe, Pb, Ge; Me': Al, B, P, Si, Group 1, Group 2, Group 3 elements of the periodic table, halogen; 0 metal composite oxides such as <x ≦ 1; 1 ≦ y ≦ 3; 1 ≦ z ≦ 8); Lithium metal; Lithium alloys; Silicon-based alloys; Tin-based alloys; SnO, SnO ₂ , PbO, PbO ₂ , Pb ₂ O ₃ , Pb ₃ O ₄ , Sb ₂ O ₃ , Sb ₂ O ₄ , Sb ₂ O ₅ , GeO, GeO ₂ , Bi ₂ O ₃ , Bi ₂ O ₄ , Metal oxides such as Bi ₂ O ₅ ; Conductive polymers such as polyacetylene; Li-Co-Ni-based materials and the like can be used, but are not limited thereto, and any negative electrode active material to be used can be used without limitation. The metal 13 is a metal having a small overvoltage with the electrode active material as compared with the electrode current collector; Or a metal having a multiphase with the electrode active material.

For example, when the electrode active material is lithium metal, a metal having a low overvoltage compared to Cu (current collector) when forming a lithium metal has a low interfacial energy when reacting with lithium metal or a diffusion energy barrier of Li ions on the metal surface. As a metal that is equal to or less than Li, the metal may be at least one selected from the group consisting of Au, Zn, Mg, Ag, Al, Pt, In, Co, Ni, Mn, and Si, and may be multiphase with the lithium metal. The metal having) may be Ca as a metal having a plurality of sites capable of reacting with lithium metal.

In addition, the tube 11 may include a semiconductor element and an oxide of the semiconductor element.

The oxide of the semiconducting element may include an oxide of the Group 14 semiconducting element of the periodic table excluding carbon. The oxide of the semiconducting element may include an oxide of Si, Ge, or Sn element.

Oxides of the semiconducting element SiOx (here 0.3 ≦ x ≦ 1.2), GeOy (here 0.2 ≦ y ≦ 1.1), SnOz (here 0.3 ≦ z ≦ 1.2), or a combination thereof, and examples thereof. For example, the oxide of the semiconducting element may be SiOx (0.3 ≦ x ≦ 1.2) or GeOy (0.2 ≦ y ≦ 1.1).

구조체 (2)Structure (2)

The present invention also relates to a structure capable of supporting an electrode active material to improve battery safety. For example, when the structure supports lithium metal as a negative electrode active material, lithium metal is dendrites at a negative electrode of a lithium metal battery. It is possible to prevent the lithium metal and the electrolyte from directly reacting with each other while preventing growth in the form of (dendrite).

The present invention is one side or both sides of the tube 11 is open; Metal 13 contained in the inner surface of the tube 11; And a lithium metal 14 formed on the metal 13; FIG. 1B.

In the case of a lithium metal battery, even when the lithium dendrite is suppressed, side reaction with the electrolyte occurs due to high reactivity, and thus, cycle efficiency is not good. Therefore, in developing a long life battery of 500 cycles or more, when the structure 10 including the lithium metal 14 inside the tube 11 is applied to the negative electrode of the lithium metal battery, the lithium metal 14 is not included. Even more advantageous.

Details of the tube aspect ratio, the properties of the tube exhibiting electrical conductivity and lithium ion conductivity, the material, composition, and metal of the shell and core are as described above.

An alloy of the metal 13 and the lithium metal 14 may be formed between the metal 13 and the lithium metal 14, and the alloy may be Li _x Au, where x is 0 <x ≦ 3.75. It may be a mistake.

Meanwhile, the hollow 12 inside the tube 11 including the metal 13 as described above may be filled with the lithium metal 14.

The lithium metal 14 may fill the inside of the hollow 12 while growing by bonding to the metal 13, and the volume of the lithium metal 14 filled in the inside of the hollow 12 may be defined as a free volume of the tube 11. By the volume ratio (α) of the lithium metal to the free volume), it can be calculated by the following formula 2, where 0 <α ≤ 1.

[Equation 2]

α = V _Li / V _F

In Formula 2, V _F is the free volume of the tube, V _Li is the volume of the lithium metal,

V _F is calculated by the following equation 3:

[Equation 3]

V _F = π (D _in / 2) ² L

In Equation 3, D _in is the inner diameter of the tube, L is the length of the tube.

Within the range of 0 <α ≦ 1, as the value of α increases, the volume of the lithium metal 14 included in the structure 10 increases, so that the cycle life of the battery may be improved.

The inner diameter D _in of the tube 11 may be 0.1 μm to 1.8 μm, preferably 0.2 μm to 1.1 μm, more preferably 0.4 μm to 0.9 μm. If it is less than the above range, the lithium metal 14 contained in the structure 10 is reduced in volume, thereby reducing lithium dendrite suppression and battery cycle life, lowering the specific capacity of the active material and the energy density per weight of the battery. If it is exceeded, it is difficult to maintain the tube shape during the manufacturing process, and the tube shape collapses during the electrode manufacturing and rolling processes, thereby reducing the lithium dendrite suppressing effect.

구조체의 제조방법Method of manufacturing the structure

The present invention comprises the steps of electrospinning (S1) the metal precursor solution and the carbon-based polymer solution to form a tube precursor;

(S2) first heat treating the tube precursor; And

(S3) a second heat treatment of the first heat-treated tube precursor; relates to a method of manufacturing a structure comprising, (S4) forming a lithium metal in the interior of the tube obtained in the step (S3); It may further include.

In the method of manufacturing a structure according to the present invention, both the first heat treatment and the second heat treatment temperature are different, and the second heat treatment temperature may be relatively higher than the first heat treatment temperature.

Hereinafter, the manufacturing method of the structure according to the present invention will be described in detail for each step.

In the step (S1), the tube precursor may be formed by electrospinning the metal precursor solution and the carbon-based polymer solution.

Electrospinning can be performed by electrospinning using double nozzles including inner and outer nozzles, using a high pressure electrospinner, using SUS (steel use stainless) as a collector, and a voltage range of 10 to 20 kV It may be performed in a tip to collector distance (TCD) range of 5 to 20 cm.

The electrospinning may use an electrospinning method that may be commonly used in the art. For example, a dual-nozzle system (Adv. Mater., 2010, 22, 496) as shown in FIG. 3 may be used.

The metal precursor solution and the carbon-based polymer solution may be injected into the inner and outer nozzles, respectively, and electrospun to form a core-shell-shaped tube precursor.

The metal precursor solution may be prepared by dissolving the metal precursor and the polymer in a solvent.

In this case, the metal precursor solution may include 0.1 to 5% by weight of the metal precursor, 1 to 20% by weight of the polymer and 75 to 95% by weight of the solvent.

The metal precursor may be at least one selected from the group consisting of alkoxides, acetylacetates, nitrates, oxalates, halides and cyanides containing metals, specifically, the metals are Au, Zn, Mg, Ag, Al , Pt, In, Co, Ni, Mn, Si and Ca may be one or more selected from the group consisting of.

In addition, when the metal is Au, precursors of Au in the group consisting of HAuCl ₄ , HAuCl ₄ · 3H ₂ O, HAuCl ₄ · 4H ₂ O, AuCl ₃ and AuCl It may be one or more selected.

When the metal precursor is less than 0.1% by weight, the metal that serves as a seed metal for growth of lithium metal cannot be sufficiently formed inside the structure, so that lithium metal cannot be filled inside the tube as much as desired, and when the metal precursor is more than 5% by weight, the total weight of the structure Since the amount of the metal to be formed increases, the amount of the lithium metal formed in the structure may be relatively reduced, thereby deteriorating the cycle life characteristics of the battery.

In addition, the polymer is polymethyl methacrylate (PMMA), polyvinylpyrrolidone (PVP), polyvinylacetate (PVAc), polyvinyl alcohol (PVA), polystyrene (PS) and polyvinylidene fluoride (PVDF) Although it may be one or more selected from the group consisting of, it is usually possible to use a wide range of polymer that can be removed at the carbonization temperature of the carbon-based polymer.

When the polymer is less than 1% by weight, it may be difficult to form a tube precursor by electrospinning, and when the polymer is more than 20% by weight, the polymer may not remain sufficiently removed during the first heat treatment to reduce battery performance.

The solvent may be at least one selected from the group consisting of methylpyrrolidone (NMP), dimethylformamide (DMF), dimethylacetamide (DMAc), dimethyl sulfoxide (DMSO), and tetrahydrofuran (THF).

When the solvent is less than 75% by weight, it may be difficult to prepare a metal precursor solution, and when the solvent is more than 95% by weight, the amount of the metal precursor and the polymer may be relatively reduced to form as much metal as desired within the structure.

The carbon-based polymer solution may be prepared by dissolving the carbon-based polymer in a solvent.

The carbon-based polymer is polyacrylonitrile (PAN), polyaniline (Polyaniline: PANI), polypyrrole (PPY), polyimide (PI), polybenzimidazole (Polybenzimidazole: PBI), polypyrrolidone ( Polypyrrolidone (Ppy), Polyamide (PA), Polyamide-imide (PAI), Polyaramide, Melamine, Melamine-Formaldehyde and Fluorine mica It may be at least one selected from the group consisting of. Meanwhile, the carbon density of the carbon included in the tube may be 2.0 to 2.5 g / cm 3.

The carbon-based polymer solution may be prepared by dissolving 1 to 20% by weight of the carbon-based polymer in 80 to 99% by weight of the solvent.

If the carbon-based polymer is less than 1% by weight, the weight of the carbon-based polymer may not be sufficient to form a tube, and thus, the tube may not be formed after electrospinning. Because of this, electrospinning may not proceed smoothly.

When the solvent is less than 80% by weight, the concentration of the carbon-based polymer solution is excessively high, so that the electrospinning may not proceed smoothly, and when the solvent is more than 99% by weight, the tube form may not be formed after the electrospinning.

The solvent used in the preparation of the metal precursor solution and the carbon-based polymer solution may be the same or different.

In the step (S2), by heating the tube precursor to the first heat treatment, it is possible to remove the polymer contained in the core of the tube precursor.

At this time, the heating temperature at the time of the first heat treatment may be 200 ℃ to 700 ℃, may be to heat treatment while raising the temperature. During the first heat treatment, the polymer included in the core of the tube precursor may be removed and the metal precursor may be reduced to form a metal.

When the first heat treatment temperature is less than 200 ° C, the polymer contained in the core of the tube precursor may not be removed and at the same time, the metal precursor may not be reduced. There is a problem that is formed.

The metal is formed on the inner surface of the tube through the reduction reaction through the heat treatment, the metal is in the form of particles, the size of the particles may be a nano size of 1 to 50 nm.

Meanwhile, the first heat treatment may be performed under an inert atmosphere. Specifically, the inert atmosphere may be formed by at least one inert gas selected from the group consisting of Ar, N ₂ , He, Ne, and Ne.

In step S3, the first heat-treated tube precursor is heated to a second heat treatment to carbonize the shell of the tube precursor to form a tube structure including carbon.

At this time, the heating temperature at the time of the second heat treatment may be more than 700 ℃ and less than 1000 ℃, if the second heat treatment temperature is 700 ℃ or less may not be completely carbonized, if the tube is formed by high temperature heat treatment if more than 1000 ℃ The physical properties of the structure may be degraded.

In particular, within the heating temperature 700 to 1000 ℃ range during the second heat treatment, it is possible to form a pore size controlled in the tube shell at a heating temperature around 800 ℃. For example, when the second heat treatment is higher than 800 ° C within the heating temperature range, the pores become small, and the lower the heating temperature below 800 ° C, the pores become larger, thereby controlling the temperature within the heating temperature range. The pore size can be controlled.

In step S4, lithium metal may be formed in the tube structure.

The method of forming the lithium metal in the tube structure may be one method selected from the group consisting of electroplating, non-plating, and evaporation, but is not limited thereto, and forms lithium metal in the tube structure. It is possible to use a wide range of filling methods.

The lithium source for forming the lithium metal may be one or more selected from the group consisting of lithium salts, lithium ingots, and lithium metal oxides, but is not limited thereto as long as the compound can provide lithium ions.

The lithium salt may be LiPF ₆ , LiClO ₄ , LiAsF ₆ , LiBF ₄ , LiSbF ₆ , LiAl0 ₄ , LiAlCl ₄ , LiCF ₃ SO ₃ , LiC ₄ F ₉ SO ₃ , LiN (C ₂ F ₅ SO ₃ ) ₂ , LiN ( C ₂ F ₅ SO ₂ ) ₂ , LiN (CF ₃ SO ₂ ) ₂ . LiN (CaF _{2a + 1} SO ₂ ) (CbF _{2b + 1} SO ₂ ), provided that a and b are natural numbers, preferably ₁ ≦ a ≦ 20 _{and 1} ≦ b ≦ 20, LiCl, LiI and LiB ( C ₂ O ₄ ) ₂ may be one or more selected from the group consisting of.

The lithium metal oxide is LiMO ₂ (M = Co, Ni, Mn), Li ₁ ₊ _x Mn ₂ _- _x O ₄ ⁺ (0≤x≤0.3) and LiNi _1-x M _x O ₂ (M = Co, Mn , Al, Cu, Fe, Mg, B or Ga, and may be at least one selected from the group consisting of 0.01 ≦ x ≦ 0.3). For example, the lithium metal oxide may be LiCoO ₂ , LiNiO ₂ , LiMn ₂ O ₄ , Li (Ni _a Mn _b Co _c ) O ₂ (a + b + c = 1), LiNi ₀ _. ₅ Mn ₁ _. ₅ O ₄ or LiNi ₀ _. ₅ Mn ₀ _. _It can be ₅ O ₂ .

The lithium metal-supported structure manufactured by the above method is applied as a negative electrode active material of a lithium metal battery, thereby solving the problem of the formation of lithium metal dendrite and the interface instability, which is a problem of the conventional lithium metal battery.

Hereinafter, preferred examples are provided to help the understanding of the present invention, but the following examples are merely for exemplifying the present invention, and various changes and modifications within the scope and spirit of the present invention are apparent to those skilled in the art. It goes without saying that changes and modifications belong to the appended claims.

실시예Example 1 : 구조체 제조 1: structure manufacture

1-1. Tube precursor formation by electrospinning

0.5% by weight of the metal precursor HAuCl _{4 and} 11% by weight of the polymer PMMA were dissolved in 88.5% by weight of the solvent to prepare a metal precursor solution. At this time, the solvent used was a mixed solvent in which dimethylformamide (DMF) and acetone were mixed in a weight ratio of 85:15.

A carbon-based polymer solution was prepared by dissolving 13% by weight of PAN, a carbon-based polymer, in 87% by weight of dimethylformamide (DMF), a solvent.

The metal precursor solution and the carbon-based polymer solution were introduced into the internal nozzle and the external nozzle of the dual-nozzle system (Adv. Mater., 2010, 22, 496) including the internal nozzle and the external nozzle, respectively, and electrospun to form a tube precursor. Was formed.

The conditions at the time of electrospinning were performed as follows.

relative humidity: 15%

Electrospinning power: 14.5 kV

Spinning solution output (flow rate)

Core = 0.9 mL / h (1.3 / 2 raito), Shell = 1.4 mL / h

1-2. First heat treatment and reduction

The tube precursor was heat-treated in a furnace at 280 ° C. to remove PMMA contained in the core of the tube precursor, and elevated temperature to reduce HAuCl ₄ to form Au particles on the inner surface of the tube precursor shell.

1-3. Second heat treatment and carbonization

Thereafter, the PAN of the tube precursor was carbonized at 850 ° C. to prepare a structure.

실시예Example 2 : 리튬 금속이 형성된 구조체 제조 2: manufacture of a structure in which a lithium metal is formed

Au of Example 1 formed lithium metal through electroplating inside the tube structure formed on the inner surface. At this time, LiClO ₄ which is a lithium salt was used as a lithium source.

At this time, the electroplating was carried out by flowing a current at a current density of 1 mA / ㎠ to a lithium half battery manufactured by the following method.

Cathode manufacturing

The structure prepared in Example 1, Super-P carbon as a conductive material and PVdF as a binder were mixed in a weight ratio of 95: 2.5: 2.5, and then coated and dried on a Cu current collector to prepare a negative electrode.

Electrolyte

As an electrolyte, 1 M LiTFSI (lithiumbis-trifluoromethanesulfonimide) dissolved in a mixed solvent of DME (1,2-dimethoxyethane) and DOL (1,3-dioxolane) (volume ratio 1: 1) and 1% LiNO ₃ electrolyte were mixed. Used.

Separator

As the separator, a polyethylene separator was used.

A lithium half cell was manufactured using the prepared negative electrode, polyethylene separator, and electrolyte solution.

비교예Comparative example 1 One

Bare Cu foil was prepared.

비교예Comparative example 2 2

In the same manner as in Example 1, a tubular structure containing no metal on the inner surface of the tube was prepared.

제조예Production Example : 리튬 반쪽전지 제조 : Lithium Half Battery

Cathode manufacturing

The structure prepared in Example 1 and Comparative Example 2, Super-P carbon as a conductive material and PVdF as a binder were mixed in a weight ratio of 95: 2.5: 2.5, and then coated and dried on a Cu current collector to prepare a negative electrode.

Electrolyte

Separator

As the separator, a polyethylene separator was used.

실험예Experimental Example 1: One: 충방전Charging and discharging 특성 실험 Characteristic experiment

In the above production example, charge and discharge were performed for the lithium half battery manufactured using the structures of Example 1 and Comparative Example 2 and the Cu current collector of Comparative Example 1, respectively. The charge / discharge test was performed under the conditions of 1 mA / cm ² current density, 1 mAh / cm ² discharge capacity, and 1 V cut-off conditions.

4A to 4C, it can be seen that the lithium half battery manufactured using the structure prepared in Example 1 does not exhibit a capacity reduction until 300 cycles.

실험예Experimental Example 2: 2: 충방전에Charging and discharging 따른 구조체의 형태 변화 관찰 The shape change of the structure

In the lithium half-cell of Experimental Example 1, the shape change exhibited by the tubular structure of Example 1 was observed before and after the charge / discharge characteristics experiment (Pristine) and charge / discharge.

FIG. 5 is a transmission electron microscopy (TEM) photograph of the lithium half battery manufactured using the structure of Example 1 before and after charging and discharging (Pristine: before charge and discharge, 20 ^th D: after the 20th discharge , 20 ^th C: after 20th charge).

Referring to FIG. 5, it can be seen that Au having a particle diameter of 15 to 20 nm is uniformly dispersed on the inner surface of the tubular structure before charging and discharging. In addition, it can be seen that during charging and discharging, lithium metal first bonds with Au inside the tube to form an Li _x Au type alloy. In particular, after the 20th charge and discharge, lithium metal is formed only in the tube and then exits. It can be seen that.

실험예Experimental Example 3: 리튬 금속의 성장 형태 관찰 3: Observing the growth form of lithium metal

After the 20th charge in the charge-discharge characteristic experiment of Experimental Example 1, the growth pattern of lithium metal was observed.

Referring to FIG. 6, in the case of a lithium half battery manufactured using the structure manufactured in Example 1, it can be seen that lithium metal dendrites are reduced in comparison with the comparative example after the 20th charge.

Although the present invention has been described above by means of limited embodiments and drawings, the present invention is not limited thereto, and the technical concept of the present invention and the following will be described by those skilled in the art to which the present invention pertains. Various modifications and variations are possible without departing from the scope of the appended claims.

[Description of the code]

10: structure

11: tube

D _ex : Tube Outer Diameter

D _in : Bore size

12: hollow

13: metal

14: electrode active material

Claims

A tube having one or both sides open; And

And a metal contained in the inner surface of the tube.
The method of claim 1,

The longitudinal aspect ratio (a) of the tube is calculated by the following equation, wherein the aspect ratio is greater than one:

[Equation 1]

a = L / D ex

In Equation 1, L is the length of the tube, D ex is the outer diameter of the tube.
The method of claim 1,

Said tube exhibiting electrical conductivity.
The method of claim 3,

The tube further exhibits lithium ion conductivity.
The method of claim 1,

The tube comprises carbon.
The method of claim 5,

Wherein said carbon is amorphous carbon.
The method of claim 1,

Said tube being porous.
The method of claim 1,

The metal is 0.1 to 25% by weight based on the total weight of the structure.
The method of claim 1,

The metal has a particle diameter of 1 to 50 nm.
The method of claim 1,

The tube is a structure for supporting the electrode active material.
The method of claim 1,

The metal included in the inner surface of the tube is a metal that is less in overvoltage with the electrode active material than the electrode current collector; Or a metal having a multiphase with the electrode active material.
The method of claim 1,

The metal contained in the inner surface of the structure is at least one selected from the group consisting of Au, Zn, Mg, Ag, Al, Pt, In, Co, Ni, Mn, Si and Ca.
The method of claim 10,

The electrode active material is a structure that is a positive electrode active material or a negative electrode active material.
The method of claim 13,

The anode active material is a lithium metal structure.
The method of claim 1,

The tube comprises a semiconductor element and an oxide of the semiconductor element,

The oxide of the semiconductor element is a structure comprising SiOx (here 0.3 ≦ x ≦ 1.2), GeOy (here 0.2 ≦ y ≦ 1.1), SnOz (here 0.3 ≦ z ≦ 1.2), or a combination thereof.
A tube having one or both sides open;

A metal contained in the inner surface of the tube; And

Lithium metal formed on the metal; structure comprising a.
The method of claim 16,

The metal is at least one structure selected from the group consisting of Au, Zn, Mg, Ag, Al, Pt, In, Co, Ni, Mn, Si and Ca.
The method of claim 16,

The structure further comprises an alloy of the metal and lithium metal formed between the metal and lithium metal.
The method of claim 18,

The alloy of the metal and the lithium metal is Li x Au structure (x is a real number 0 <x <3.75).
The method of claim 16,

The volume ratio α of lithium metal to the free volume of the tube is calculated by Equation 2 below, wherein the volume ratio α of lithium metal is 0 <α ≦ 1:

[Equation 2]

α = V Li / V F

V F Is the free volume of the tube, V Li Is the volume of lithium metal,

V F Is calculated by the following equation:

[Equation 3]

V F = π (D in / 2) 2 L

D in is the inner diameter of the tube and L is the length of the tube.