KR20230096616A - A Current Collector for Lithium Metal Battery for Inhibiting Growth of Dendritic Lithium and Manufacturing Method Thereof - Google Patents

Abstract

The present invention relates to a current collector for a lithium metal battery including: a conductive thin film having a wrinkled structure on the surface thereof; a graphene single layer formed on the conductive thin film; and a plurality of metal nanoparticles formed on the graphene single layer, and a manufacturing method thereof. The present invention can ensure safety and can obtain high coulombic efficiency and improved lifespan characteristics.

Description

Current Collector for Lithium Metal Battery for Inhibiting Growth of Dendritic Lithium and Manufacturing Method Thereof}

The present invention relates to a current collector for a lithium metal battery and a method for manufacturing the same for suppressing the growth of single-sided dendrite lithium having a surface wrinkled structure and having metal nanoparticles introduced therein.

Lithium metal has been considered the most ideal anode material due to its high theoretical specific capacity of 3,862 mAh/g, low weight density of 0.531 g/cm ³ and the lowest reduction potential of -3.04 V compared to a standard hydrogen electrode (SHE). However, lithium metal has a critical limitation in its use as an anode. The non-uniform distribution of lithium at the anode during repetitive charging and discharging processes generates dendritic Li and dead Li, which cause safety problems such as low coulombic efficiency and internal short circuit. In particular, dendrite lithium forms inactive lithium that does not have electrical contact with the anode current collector during battery discharge, which may cause a decrease in energy density of the anode. In addition, the anode surface area is continuously increased by the dendrite lithium, resulting in the increase and accumulation of the passivation layer. Due to this, the lithium metal and the electrolyte are continuously consumed, which deteriorates the efficiency and cycle characteristics of the lithium metal battery. Furthermore, the separator may be destroyed by dendrite lithium, and thus battery stability may be greatly deteriorated, such as explosion of the battery.

Therefore, technology for controlling lithium deposition at the anode of a lithium metal battery is the most important factor in realizing practical applications of a lithium metal battery.

Various strategies have been proposed to obtain uniform lithium deposition, including interface control, introduction of protective layers, and structural design of electrodes. Considering that most current collectors used in lithium battery systems are planar and have numerous small grains with randomly oriented planes, among these various strategies, structural control of the current collector as a key element in electrode design is a key factor in the formation of dendrite lithium. can play an important role in mitigation. Typically used copper current collectors cannot ensure uniform lithium electrodeposition without lithium dendrite formation. As a strategy for structural control of the current collector for uniform lithium electrodeposition, the technique of introducing a seed highly reactive with lithium into a three-dimensional copper frame is known to be able to uniformly distribute the electric field and the flow of lithium ions. . However, detailed and specific R&D on this has not been made to date.

Accordingly, it is necessary to develop a technology for controlling uniform lithium deposition at the anode of a lithium metal battery.

The present invention is to solve the above problems, in order to suppress the formation of dendrite lithium and improve the lifespan and efficiency of a lithium metal battery, a surface wrinkle structure is formed on a conductive thin film constituting an anode current collector, and lithium and reactivity An object of the present invention is to provide a current collector for a lithium metal battery and a method for manufacturing the same for suppressing growth of dendritic lithium that induces uniform lithium deposition by introducing predetermined metal nanoparticles after introducing good graphene.

According to one embodiment of the present invention, a conductive thin film having a wrinkle structure formed on its surface; a graphene single layer formed on the conductive thin film; and a plurality of metal nanoparticles formed on the graphene single layer.

In addition, according to another embodiment of the present invention, forming a first metal-containing thin film on the conductive thin film; heating the conductive thin film on which the first metal-containing thin film is formed; forming a graphene monolayer while removing the first metal-containing thin film from the conductive thin film by bringing a graphene precursor gas and a reducing gas into contact with the first metal-containing thin film on the conductive thin film; Forming a plurality of second metal nanoparticles on the graphene single layer on the conductive thin film; provides a method for manufacturing a current collector for a lithium metal battery including.

According to a current collector for a lithium metal battery and a method for manufacturing the same for suppressing the growth of dendritic lithium of the present invention, a wrinkle structure is formed on the surface of a conductive thin film and the distribution of predetermined metal nanoparticles is optimized, thereby reducing the nucleus formation of lithium. The overvoltage is lowered, and the metal nanoparticles act as an active site for the lithium nucleus growth reaction, thereby inducing uniform lithium nucleus growth and subsequent growth. The uniform electrodeposition of lithium obtained through this suppresses lithium dendrite growth at the anode to prevent internal short circuit of the lithium metal battery, thereby securing safety, and obtaining high coulombic efficiency and improved life characteristics.

1 is a schematic diagram showing a surface modification process of a conductive thin film according to an embodiment of the present invention.
2A to 2H are scanning electron microscope (SEM) photographs of current collectors according to Preparation Example 1 and Comparative Preparation Examples 1 to 7 of the present invention.
3A to 3D are scanning electron micrographs of current collectors according to Preparation Example 1 and Comparative Preparation Examples 1 to 3 of the present invention when the charging capacity is 0.5 mAh/cm 2 .
4A to 4D are graphs illustrating coulombic efficiency according to cycles when the silver electrodeposition thickness is changed to 1 nm, 2 nm, and 5 nm.
5a to 5c are lithium metal batteries to which current collectors according to Preparation Example 1, Comparative Preparation Example 1, and Comparative Preparation Example 7 are applied when the charging capacity is changed to 0.5 mAh/cm2, 1 mAh/cm2, and 5 mAh/cm2 It is a graph showing the coulombic efficiency according to the cycle of

Hereinafter, a current collector for a lithium metal battery and a method for manufacturing the current collector for suppressing growth of dendrite lithium will be described in detail so that those skilled in the art can easily carry out the present invention.

A lithium metal battery is a battery using lithium metal or a lithium alloy as an anode, and lithium metal has the highest energy density among anode materials known to date and has a very low oxidation-reduction potential. Theoretically, a lithium metal battery has a very high energy capacity, but due to its high electrochemical reactivity, it reacts with an electrolyte to form a thick resistive layer on the surface, and as a result, the battery's resistance is increased and the capacity can be reduced during charging and discharging. In addition, lithium is deposited only in a specific area to form dendritic lithium, which is a dendritic precipitate, and the dendritic lithium grows and passes through a separator to reach the cathode, which is the opposite electrode, short-circuiting the battery or causing the battery to explode. .

The dendritic lithium refers to a twig-shaped crystal that abnormally grows on a part of a metal surface. When lithium metal is used as an anode, electrons and lithium ions escape from the anode to the cathode during discharge, and electrons and lithium ions in the cathode gather again on the anode electrode plate during charging. If the metal continues to grow and touches the anode, it can cause an explosion. In addition, dendrite lithium can cause volume expansion of electrodes and side reactions between electrodes and electrolytes, which can reduce the safety and lifespan of lithium metal batteries. This phenomenon may be accelerated when lithium nucleation is not smoothly performed.

In order to improve the stability and efficiency of lithium metal batteries, there are methods such as 1) electrolyte design, 2) lithium ion flux control, and 3) lithium nucleation control. It is a technology that suppresses the growth of lithium dendrites and induces uniform lithium deposition by controlling nucleation. Specifically, the specific metal dispersed in atomic units in the lithium anode can serve as a seed leading to uniform lithium distribution by forming a solid solution with lithium and lowering the interface energy during lithium electrodeposition. Lithium nucleation control technology uses this principle.

A current collector for a lithium metal battery for suppressing the growth of lithium dendrites according to an embodiment of the present invention includes a conductive thin film having a wrinkled structure formed on the surface; a graphene single layer formed on the conductive thin film; and a plurality of metal nanoparticles formed on the graphene single layer.

The current collector is an important component in manufacturing a thin-film electrode plate, and may serve as a passage through which electrons are transferred from the outside so that an electrochemical reaction occurs in the electrode active material, or electrons are received from the electrode active material and flowed to the outside. In general, a slurry containing a binder solution, an electrode active material, and a conductive material is applied to a conductive foil to manufacture an electrode plate.

The conductive thin film may include at least one selected from the group consisting of copper, nickel, aluminum, magnesium, titanium, and alloys thereof, preferably copper, but if it does not cause chemical change in the lithium metal battery It is not particularly limited thereto as long as it has high conductivity. When the conductive thin film is made of copper, the current collector including the conductive thin film made of copper can have excellent electrochemical stability and improved electrical conductivity in a lithium metal battery, and thus can have a uniform current distribution in the anode. , can be very effective in realizing a large-area battery. Furthermore, the anode current collector including a conductive thin film made of copper has excellent mechanical strength, so cracks and deformation can be minimized even after repeated charging and discharging, and copper can be used at a low cost compared to other metals. there is

In addition, copper has a very low affinity for carbon, so it has a very low graphene solubility compared to other metals. Therefore, since copper can promote the growth of graphene, it can be a suitable substrate material for growing graphene by chemical vapor deposition (CVD).

The wrinkle structure formed on the conductive thin film may include at least one concave-convex portion formed at regular intervals, and the concave-convex portion may include a protruding portion and a concave portion. The wrinkle structure formed on the conductive thin film may be formed after forming a graphene single layer on the conductive thin film. Specifically, in the process of forming a graphene monolayer on a conductive thin film serving as a substrate and then cooling, the conductive thin film expands and contracts due to a difference in thermal expansion energy between the conductive thin film and the graphene monolayer formed on the conductive thin film. It may be formed through the process of becoming.

Specifically, in the wrinkle structure, the average distance between the protrusions included in the two adjacent concave-convex portions may be 270 to 290 nm, preferably 275 to 285 nm. In addition, the average height between the protruding portion and the concave portion of the uneven portion may be 9 to 13 nm, preferably 10 to 12 nm.

The wrinkled structure formed on the conductive thin film may have an effect of delocalizing lithium ion flux by increasing the binding energy between the conductive thin film and lithium, thereby enabling uniform electrodeposition of lithium and dendrite lithium. formation can be prevented.

The conductive thin film may include a crystalline structure in which adjacent crystal grains have the same orientation direction, and preferably may include a crystalline structure composed of [100]-oriented crystal grains. The crystalline structure composed of the [100]-oriented crystal grains may be formed during a process of forming a sacrificial layer including metal nanoparticles on the conductive thin film. Specifically, after forming a sacrificial layer thin film including metal nanoparticles on the conductive thin film and raising the temperature to a high temperature of about 1000° C., forming a graphene monolayer on the sacrificial thin film and raising the temperature back to room temperature. In this process, the sacrificial layer including the metal nanoparticles may be removed. While the sacrificial layer is removed, a change in the nucleation energy of the carbon dimer may be induced due to a weak carbon-metal bond, and as a result, the metal nanoparticles included in the sacrificial layer are crystals composed of [100]-oriented crystal grains. A conductive thin film comprising a sexual texture may be induced to form.

The metal of the metal nanoparticles included in the sacrificial layer may be at least one selected from the group consisting of gold (Au), silver (Ag), tin (Sn), and zinc (Zn), preferably silver (Ag ) may be. In particular, when silver nanoparticles are included in the sacrificial layer, it may be effective to form a crystalline structure including a uniform and even orientation of crystal grains in the conductive thin film.

The formed [100]-oriented crystalline grains can form uniform lithium adsorption energy on the surface, thereby changing the surface properties to a lithophilic state. The energy barrier for crystal nucleation can be lowered.

The graphene single layer is a group consisting of chemical vapor deposition (CVD), rapid thermal annealing (RTA), atomic layer deposition (ALD), and physical vapor deposition (PVD) It may be formed on the conductive thin film by at least one method selected from, and preferably may be formed by chemical vapor deposition.

The chemical vapor deposition methods include rapid thermal chemical vapor deposition (RTCVD), inductively coupled plasma-chemical vapor deposition (ICP-CVD), low pressure chemical vapor deposition (Low Pressure Chemical Vapor Deposition; LPCVD), atmospheric pressure chemical vapor deposition (APCVD), metal organic chemical vapor deposition (MOCVD) and plasma-enhanced chemical vapor deposition (PECVD) from the group consisting of It may be at least one selected, preferably high-temperature chemical vapor deposition, but is not limited thereto as long as it is a method commonly used for graphene growth in the art.

The metal of the plurality of metal nanoparticles formed on the graphene single layer may be at least one selected from the group consisting of gold, silver, tin, and zinc. The metal is characterized by a high standard reduction potential compared to lithium ion, and acts as a heterogenous nucleation site by forming an alloy phase with lithium before forming a pure lithium phase (Li0) to selectively disperse lithium deposition can make it

The plurality of metal nanoparticles may be uniformly distributed on the graphene single layer. The plurality of metal nanoparticles have a strong affinity for lithium, and are uniformly distributed on the graphene single layer to induce uniform electrodeposition of lithium on the surface of the current collector, thereby preventing the formation of dendritic lithium.

When the amount of deposition of the plurality of metal nanoparticles is small on the graphene single layer, metal nanoparticles of various sizes are distributed, resulting in uneven surface, so that lithium dendrites can grow, and when the amount of deposition of the plurality of metal nanoparticles is high Aggregation between particles occurs, resulting in non-uniformity of the surface, which may also cause a problem of growth of lithium dendrites.

The metal nanoparticles distributed on the graphene single layer may have a diameter of 20 to 50 nm, preferably 30 to 40 nm. The diameter of the metal nanoparticle may be determined by the thickness of a metal thin film layer deposited by electron beam deposition.

A method for manufacturing a current collector for a lithium metal battery for inhibiting growth of lithium dendrites according to another embodiment of the present invention includes forming a first metal-containing thin film on a conductive thin film; heating the conductive thin film on which the first metal-containing thin film is formed; forming a graphene monolayer while removing the first metal-containing thin film from the conductive thin film by bringing a graphene precursor gas and a reducing gas into contact with the first metal-containing thin film on the conductive thin film; Forming a plurality of second metal nanoparticles on the graphene single layer on the conductive thin film; provides a method for manufacturing a current collector for a lithium metal battery including.

The conductive thin film may include at least one selected from the group consisting of copper, nickel, aluminum, magnesium, titanium, and alloys thereof, preferably copper, but if it does not cause chemical change in the lithium metal battery The forming of the first metal-containing thin film may be performed by irradiating an electron beam. Specifically, the first metal-containing thin film may be deposited on the conductive thin film by injecting the conductive thin film into an electron beam evaporator and irradiating an electron beam.

The step of forming the first metal-containing thin film may be to form the first metal-containing thin film to a thickness of 150 to 250 nm, preferably to a thickness of 180 to 220 nm, more preferably to a thickness of 190 to 210 nm. A metal-containing thin film may be formed. When the thickness of the first metal-containing thin film has a value within the above numerical range, it is possible to form a crystalline textured crystal plane in which adjacent crystal grains have the same orientation direction, thereby enabling surface control. On the other hand, when the thickness of the first metal-containing thin film exceeds the upper limit, metal particles may remain in the conductive thin film even after the subsequent heating step, and when the thickness is less than the lower limit, uniform surface control is impossible.

The metal of the first metal-containing thin film may be at least one selected from the group consisting of gold, silver, tin, and zinc, and preferably may be silver (Ag). In particular, when silver nanoparticles are included in the sacrificial layer, it may be effective to form a crystalline structure including a uniform and even orientation of crystal grains in the conductive thin film.

The step of heating the conductive thin film on which the first metal-containing thin film is formed may be performed at a temperature of 850 to 1100 ° C for 0.5 to 2.5 hours, preferably at a temperature of 900 to 1050 ° C for 0.8 to 2.2 hours it could be When the heating temperature for the conductive thin film exceeds the upper limit of the numerical range, excessive energy is unnecessarily consumed, and when the heating temperature does not reach the lower limit of the numerical range, a graphene single layer is formed on the conductive thin film. It may not be.

Thereafter, a graphene single layer may be formed while removing the first metal-containing thin film from the conductive thin film by bringing a graphene precursor gas and a reducing gas into contact with the first metal-containing thin film on the conductive thin film.

The graphene precursor gas may be at least one selected from the group consisting of hydrocarbon gas, gaseous hydrocarbon compound, gaseous alcohol having 1 to 6 carbon atoms, and carbon monoxide. Specifically, the graphene precursor gas may include at least one selected from the group consisting of methane, ethane, propane, butane, ethylene, propylene, butylene, acetylene, butadiene, benzene, methanol, ethanol, propanol, and butanol. and preferably methane.

In the step of forming the graphene monolayer, the graphene precursor gas may be introduced at a flow rate of 40 to 60 sccm, preferably 45 to 55 sccm. When the flow rate of the graphene precursor gas is less than the lower limit of the numerical range, the graphene monolayer may not be uniformly formed due to insufficient carbon source.

The reducing gas may include at least one selected from the group consisting of hydrogen gas, methane gas, argon gas, or a mixed gas thereof, and may preferably be hydrogen gas.

In the step of forming the graphene monolayer, the reducing gas may be introduced at 6 to 10 sccm, preferably at 7 to 9 sccm. Oxidation of the conductive thin film may be prevented by performing heat treatment under a reducing gas atmosphere, and thus growth of a graphene monolayer on the conductive thin film may be promoted.

In the process of forming the graphene single layer, the first metal-containing thin film formed on the conductive thin film may be removed. A change in the nucleation energy of the carbon dimer may be induced due to the weak carbon-metal bond, and as a result, the metal nanoparticles included in the first metal-containing thin film have a crystalline structure composed of [100]-oriented crystal grains. A conductive thin film containing may be formed.

In the step of forming a plurality of second metal nanoparticles on the graphene single layer on the conductive thin film, the metal of the second metal nanoparticles may be at least one selected from the group consisting of gold, silver, tin, and zinc. The metal is characterized by a high standard reduction potential compared to lithium ion, and acts as a heterogenous nucleation site by forming an alloy phase with lithium before forming a pure lithium phase (Li0) to selectively disperse lithium deposition and thereby inhibiting the formation of dendrite lithium.

Forming the second metal nanoparticles on the graphene single layer may be performed by irradiating an electron beam. Specifically, the second metal nanoparticle may be deposited on the graphene single layer by injecting the conductive thin film on which the graphene single layer is formed into an electron beam evaporator and irradiating an electron beam. The diameter of the second metal nanoparticle may be determined by the thickness of the second metal thin film layer deposited by electron beam deposition.

The forming of the second metal nanoparticles may include forming a second metal-containing thin film to a thickness of 1.5 to 3 nm. When the thickness of the second metal-containing thin film layer satisfies a value within the above numerical range, it is possible to form uniform second metal nanoparticles, thereby suppressing the generation of dendrite lithium and improving battery performance.

A lithium metal battery according to another embodiment of the present invention includes a current collector for a lithium metal battery; and a lithium metal-containing electrode. Specifically, the lithium metal battery may include a lithium metal-containing anode, a cathode, an electrolyte and a separator including the current collector.

The electrolyte may include at least one selected from the group consisting of LiTFSI, DOL, DME, and LiNO ₃ .

Hereinafter, the present invention will be described in more detail through examples. However, these examples are only for helping the understanding of the present invention, and the scope of the present invention is not limited to these examples in any sense.

<Preparation Example 1> Preparation of a current collector for a lithium metal battery having a surface wrinkle structure, a [100]-crystal plane, and a single layer of graphene, in which silver nanoparticles (30 to 40 nm in diameter) are uniformly dispersed

200 nm of silver was deposited by electron beam evaporation on a 20 μm-thick copper foil prepared for the fabrication of an anode current collector that inhibits the growth of dendrite lithium, and the silver was placed facing up in a 4-inch CVD transparent quartz tube (100 mm X 1100 mm). Then, while flowing 8 sccm of hydrogen, the mixture was heated to 1000 ℃ for 1 hour in a vacuum state. Then, after a pretreatment process for 2 hours while flowing only 50 sccm of methane, a graphene monolayer was grown on the copper foil while simultaneously flowing 8 sccm of hydrogen and 50 sccm of methane for 10 minutes. Thereafter, after cooling by lowering the temperature to room temperature while flowing only 8 sccm of hydrogen, the sample is taken out of the CVD transparent quartz tube. Thereafter, 2 nm of silver was deposited on the graphene monolayer by electron beam evaporation to form silver nanoparticles of 30 to 40 nm.

<Comparative Preparation Example 1> Preparation of current collector for lithium metal battery without introduction of surface wrinkle structure, [100]-crystal plane, graphene single layer and silver nanoparticles

Only copper foil (manufacturer: UACJ, product number: C1100, component: Cu 99.9 or more) was used as a current collector for a lithium metal battery without introducing a surface wrinkle structure.

<Comparative Preparation Example 2> Preparation of a current collector for a lithium metal battery having a surface wrinkle structure, a [100]-crystal plane, and a single layer of graphene, in which silver nanoparticles (diameter of 10 nm to 50 nm) are non-uniformly introduced

It was prepared under the same conditions as in Preparation Example 1, except that 1 nm of silver was deposited on the graphene monolayer by electron beam evaporation.

<Comparative Preparation Example 3> Preparation of a current collector for a lithium metal battery having a surface wrinkle structure, a [100]-crystal plane, and a single layer of graphene and silver nanoparticles covering the surface thereof

It was prepared under the same conditions as in Preparation Example 1, except that 5 nm of silver was deposited on the graphene monolayer by electron beam evaporation. As a result, a film was formed in the form of aggregation of silver nanoparticles.

<Comparative Preparation Example 4> Preparation of a current collector for a lithium metal battery having a surface wrinkle structure and a [100]-crystal plane and uniformly dispersed silver nanoparticles (diameter 10 to 20 nm)

After manufacturing a current collector under the same conditions as in Preparation Example 1, a reactive ion etcher (RIE) was used to remove graphene generated with 100 sccm oxygen plasma, and a copper collector having a surface wrinkle structure and a [100]-crystal plane. 2 nm of silver was electron beam deposited over the entire surface.

<Comparative Preparation Example 5> Preparation of a current collector for a lithium metal battery having a surface wrinkle structure and a graphene single layer, in which silver nanoparticles (diameter of 10 to 50 nm) are non-uniformly dispersed

It was prepared under the same conditions as in Preparation Example 1, except that the process of electron beam deposition of 200 nm of silver on the copper foil was omitted.

<Comparative Preparation Example 6> Preparation of a current collector for a lithium metal battery in which there is no surface wrinkle structure, 100 crystal planes and graphene monolayer, and silver nanoparticles (diameter 10 to 50 nm) are non-uniformly dispersed

After manufacturing the current collector under the same conditions as in Preparation Example 1 except for omitting the process of electron beam deposition of 200 nm of silver on the copper foil, a reactive ion etcher (RIE) was used to generate oxygen plasma of 100 sccm After removing the graphene, 2 nm of silver is deposited by electron beam evaporation on the copper current collector having a surface wrinkle structure (since there is no step of pre-depositing silver, the [100]-crystal plane is not formed and there is no graphene) .

<Comparative Preparation Example 7> Preparation of a current collector for a lithium metal battery having a surface wrinkle structure, 100 crystal planes, and a single layer of graphene and not introducing silver nanoparticles

A current collector was manufactured under the same conditions as in Preparation Example 1, except for the process of depositing 2 nm of silver on the graphene single layer by electron beam evaporation.

<Example 1> SEM image analysis of a current collector for a lithium metal battery

2a to 2g show the results of observing SEM images of current collectors according to Preparation Example 1 and Comparative Preparation Examples 1 to 7.

In the case of Preparation Example 1, it can be seen that the silver nanoparticles are arranged with regular intervals and shapes (FIG. 2a). On the other hand, as can be seen in the case of Comparative Preparation Example 4, in the absence of graphene, it can be confirmed that the deposited silver nanoparticles are densely deposited without gaps (FIG. 2e), and through this, graphene reduces the arrangement spacing of silver nanoparticles. It can be seen that it influences control. In addition, in Comparative Preparation Example 5, it can be seen that the presence or absence of the [100]-crystal plane affects the shape of the silver nanoparticles, and the presence of graphene controls the spacing of the silver nanoparticles (FIG. 2f ).

<Example 2> Analysis of factors affecting the formation of dendritic lithium

3a to 3d show SEM images of Preparation Example 1 and Comparative Preparation Examples 1 to 3 when the charging capacity is 0.5 mAh/cm ² .

In the case of Preparation Example 1, when charging (lithium electrodeposition) occurred, lithium electrodeposition occurred in a horizontal direction, resulting in a relatively uniform surface on which dendrite lithium did not grow (FIG. 3a). In the case of Comparative Preparation Example 1, it was confirmed that dendrite lithium grew due to the non-uniform surface of copper (FIG. 3b).

In the case of Comparative Preparation Examples 2 and 3, it was confirmed that dendritic lithium grew due to non-uniform lithium electrodeposition due to non-uniform distribution of silver nanoparticles (FIG. 3c and 3d).

<Example 3> Analysis of the effect of silver electrodeposition thickness on battery life

4A to 4D show the thickness of silver electrodeposition on a copper current collector having a surface wrinkle structure, a [100]-crystal plane, and a single layer of graphene, 1 nm (Comparative Preparation Example 2), 2 nm (Production Example 1), and 5 nm ( It is a graph showing the coulombic efficiency according to the cycle until lithium is electrodeposited at 2 nm in the case of Comparative Preparation Example 3).

Figure 4a is a comparison of non-uniform lithium electrodeposition with silver electrodeposition of 1 nm and 5 nm thickness, with life characteristics measured at a current density of 0.5 mA/cm2 and a capacity of 1.0 mAh/cm2 when a Li/Cu half-cell was constructed. Compared to Preparation Example 2 and Comparative Preparation Example 3, it can be seen that the lifespan characteristics of Preparation Example 1 exhibiting uniform lithium electrodeposition with 2 nm-thick silver electrodeposition are improved.

4b to 4d show charge and discharge curves according to cycles of Preparation Example 1, Comparative Preparation Example 2 and Comparative Preparation Example 3, and in the case of Comparative Preparation Example 2 and Comparative Preparation Example 3, the coulombic efficiency of Although the capacity decreases (FIGS. 4b and 4d), in the case of Preparation Example 1, the coulombic efficiency does not decrease with the progress of the cycle, so it can be seen that the battery life is improved and the performance is improved (FIG. 4c).

<Example 4> Analysis of battery life characteristics according to current density

5a to 5c show a current density of 0.5 mAh/cm 2 , 1 under the same conditions as a charging capacity of 1.0 mAh/cm 2 in a lithium metal battery to which current collectors according to Preparation Example 1, Comparative Preparation Example 1, and Comparative Preparation Example 7 were applied. It is a graph showing the coulombic efficiency according to the cycle in the case of different mAh/cm 2 and 5 mAh/cm 2 .

Specifically, FIG. 5a shows the results of an experiment conducted with 0.5 V cuf-off at a current density of 0.5 mA/cm ² and discharging after charging for 2 hours at a current density of 0.5 mA/cm ² , and FIG. ² Discharge after charging for 1 hour at a current density is the ^result of the experiment with 0.5 V cuf-off at a current density of 1.0 mA/cm ² , and FIG. 5c shows a 5.0 It is a figure showing the result of the experiment with 0.5 V cuf-off at mA/cm ² current density.

As shown in FIG. 5a, at a low current density of 0.5 mA/cm ² , there was no significant difference in cycle life and coulombic efficiency between the case where silver nanoparticles were used and not used, but as shown in FIGS. 5b and 5c, 1.0 mA/cm 2 At a high current density of cm ² or more, it was confirmed that the battery life and capacity were improved by introducing the silver nanoparticles, resulting in better battery performance.

Claims (19)

A conductive thin film having a wrinkle structure formed on its surface;
a graphene single layer formed on the conductive thin film; and
a plurality of metal nanoparticles formed on the graphene single layer;
A current collector for a lithium metal battery comprising a. The method of claim 1,
The corrugated structure includes at least one concave-convex portion formed at regular intervals, and the concave-convex portion includes a protruding portion and a concave portion. The method of claim 2,
A current collector for a lithium metal battery in which an average distance between protrusions included in the two adjacent concavo-convex portions is 270 to 290 nm. The method of claim 2,
A current collector for a lithium metal battery having an average height between the protruding portion and the concave portion of the uneven portion of 9 to 13 nm. The method of claim 1,
The conductive thin film is at least one current collector for a lithium metal battery selected from the group consisting of copper, nickel, aluminum, magnesium, titanium, and alloys thereof. The method of claim 1,
The metal of the metal nanoparticles is at least one selected from the group consisting of gold, silver, tin, and zinc current collector for a lithium metal battery. The method of claim 1,
The conductive thin film is a current collector for a lithium metal battery comprising a polycrystalline structure in which adjacent crystal grains have the same orientation direction. The method of claim 1,
The conductive thin film is a current collector for a lithium metal battery comprising a crystalline structure made of [100]-oriented crystal grains. The method of claim 1,
The plurality of metal nanoparticles are uniformly distributed on the graphene single layer, the current collector for a lithium metal battery. The method of claim 1,
The current collector for a lithium metal battery having a diameter of 20 to 50 nm of the metal nanoparticles. Forming a first metal-containing thin film on the conductive thin film;
heating the conductive thin film on which the first metal-containing thin film is formed;
forming a graphene monolayer while removing the first metal-containing thin film from the conductive thin film by bringing a graphene precursor gas and a reducing gas into contact with the first metal-containing thin film on the conductive thin film;
forming a plurality of second metal nanoparticles on a graphene single layer on the conductive thin film;
Method for manufacturing a current collector for a lithium metal battery comprising a. The method of claim 11,
The step of forming the first metal-containing thin film is a method of manufacturing a current collector for a lithium metal battery in which the first metal-containing thin film is formed to a thickness of 150 to 250 nm. The method of claim 11,
The heating step is a method of manufacturing a current collector for a lithium metal battery that is performed at a temperature of 850 to 1100 ° C. for 0.5 to 2.5 hours. The method of claim 11,
The step of forming the graphene single layer is a method of manufacturing a current collector for a lithium metal battery that is performed by introducing a graphene precursor gas at a flow rate of 40 to 60 sccm and a reducing gas at a flow rate of 6 to 10 sccm. The method of claim 11,
The graphene precursor gas is a current collector for a lithium metal battery including at least one selected from the group consisting of methane, ethane, propane, butane, ethylene, propylene, butylene, acetylene, butadiene, benzene, methanol, ethanol, propanol, and butanol. Manufacturing method of. The method of claim 11,
The reducing gas is a method of manufacturing a current collector for a lithium metal battery comprising at least one selected from the group consisting of hydrogen gas, methane gas, argon gas, or a mixture thereof. The method of claim 11,
The method of manufacturing a current collector for a lithium metal battery in which the forming of the first metal-containing thin film and the second metal nanoparticles is performed by irradiating an electron beam. The method of claim 11,
The step of forming the second metal nanoparticles is a method of manufacturing a current collector for a lithium metal battery in which a second metal-containing thin film is formed to a thickness of 1.5 to 4 nm. A current collector for a lithium metal battery according to any one of claims 1 to 10; and
a lithium metal-containing electrode;
A lithium metal battery comprising a.

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