KR20210065745A - Electrochemical device comprising an active layer with a controlled porosity and a method of manufacturing the same - Google Patents

Abstract

The present invention relates to an electrochemical device that includes an ion storage layer capable of storing ions; and an active layer whose conductivity varies depending on the ion concentration of a dopant material. The active layer is a layer whose porosity is controlled by the degree of vacuum in a deposition process. It can be applied to all applications using the ion behavior mechanism and control the porosity to control the behavior of ions in a device, thereby controlling the properties easily.

Description

An electrochemical device comprising an active layer with a controlled porosity and a method of manufacturing the same

The present invention relates to an electrochemical device including an active layer with controlled porosity in order to excellently control ion behavior and a method for manufacturing the same, and can be applied to various applications using an ion movement mechanism such as an energy storage device, a memory device, etc. It relates to an electrochemical device that can be

Background to the present disclosure is provided herein, which does not necessarily imply known art.

Many applications such as an energy storage device and a memory device using the movement mechanism of ions have been used throughout real life, and the Research is also being actively carried out. As these devices are operated by the movement of ions, it is important to excellently control the ionic behavior characteristics such as mobility and the amount of moving ions in order to control the characteristics and improve the performance of the device.

For example, in the case of a Li-ion battery, which is one of the energy storage devices, high capacity and fast charging/discharging characteristics can be secured through a larger amount of lithium ions and faster lithium ion movement. . Also, in the case of a memory device, not only a large memory window but also fast switching can be realized through a large number of ions and faster ion movement. That is, effective control of ion behavior is required in order to adjust and improve device characteristics and performance according to preference.

Conventionally, in order to improve the performance of a lithium ion battery, for example, rate capability, a LiCoO ₂ powder surface-modified as a cathode material is used (Korea Patent No. 10-2018470, 2019.08.29.), or resistance By forming a metal oxide layer doped with nitrogen as a resistance change layer of a changeable memory device, a switching phenomenon with sufficient on/off current ratio is provided without a high voltage forming process (Korean Patent No. 10- No. 1764983, 2017.07.28.).

1. Korean Patent Registration No. 10-2018470 (2019.08.29.) 2. Korean Patent No. 10-1764983 (2017.07.28.)

An object of the present invention is to provide an electrochemical device including an active layer with controlled porosity, thereby controlling ion behavior in the device, and thus providing an electrochemical device capable of easily controlling device characteristics and a method for manufacturing the same.

However, the objects of the present invention are not limited to the above-mentioned objects, and other objects not mentioned will be clearly understood by those skilled in the art from the following description.

The present invention provides an ion storage layer capable of storing ions; and an active layer whose conductivity varies depending on the ion concentration of the dopant material, wherein the active layer is a layer whose porosity is controlled by a degree of vacuum during deposition.

In addition, the active layer is a layer formed of a compound containing a dopant material, and the dopant material is any selected from the group consisting of Li, H, Cu, Ag, Na, Mg, Fe, Ni, Ti, Te, O and Ca. It includes one or more, and the compound is characterized in that it includes any one or more selected from the group consisting of oxides, sulfides, phosphates and silicates.

In addition, the ion storage layer is amorphous silicon (a-Si), titanium dioxide (TiO ₂ ), graphite (graphite), carbon (carbon), lithium (Li), tungsten oxide (WO ₃ ) and carbon nanotubes (CNT), Molybdenum oxide (MoO _x ), tungsten selenium (WSe _x ), vanadium oxide (VO ₂ ) It is characterized in that it contains any one or more selected from the group consisting of.

In addition, the active layer is characterized in that the porosity is controlled by controlling the degree of vacuum during deposition within the range of 1 to 100 mTorr.

The present invention also provides an energy storage device including the electrochemical device.

The present invention also provides a memory device including the electrochemical device.

In addition, the present invention comprises the steps of forming an ion storage layer capable of storing ions; and forming an active layer whose conductivity varies depending on the ion concentration of the dopant material, wherein the forming of the active layer is formed by a deposition method, and is a step of controlling porosity by vacuum during deposition. A manufacturing method is provided.

In addition, the step of forming the active layer is deposited using sputtering, pulsed laser deposition, chemical vapor deposition, atomic layer deposition, or molecular beam epitaxial deposition, and the vacuum degree during deposition is adjusted within the range of 1 to 100 mTorr. It is characterized in that it is a step. .

The present invention provides an electrochemical device including an active layer with controlled porosity, so that it can be applied to all applications using an ion behavior mechanism, and by controlling the porosity, the ion behavior in the device is controlled and properties can be easily obtained through this. can be adjusted That is, by providing an effective control method for ion behavior, device characteristics and performance can be adjusted and improved according to preference.

More specifically, when the electrochemical device according to the present invention is applied to an energy storage device, high capacity and fast charging/discharging characteristics can be provided, and it can be applied to a resistance variable memory device. In this case, fast switching as well as a large memory window can be realized through many ions and faster ion movement.

1 shows a photograph of a surface image of a membrane whose porosity is controlled according to an embodiment of the present invention.
2 is a schematic diagram of a resistance variable memory device to which an electrochemical device according to an embodiment of the present invention is applied.
3 shows the CV and IV analysis results according to the porosity of the active layer according to an embodiment of the present invention.
4 shows a measurement result of a change in conductivity with respect to an external electric pulse according to the porosity of the ion storage layer according to an embodiment of the present invention.
5 shows a measurement result of a change in conductivity with respect to an external electric pulse according to porosity according to an embodiment of the present invention.

All technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art, unless otherwise stated. Also throughout this specification and claims, unless otherwise indicated, the term comprise, comprises, comprising is meant to include the recited object, step or group of objects, and steps, and any other It is not used in the sense of excluding an object, step, or group of objects or groups of steps.

Prior to describing the present invention in detail below, it is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the present invention, which is limited only by the appended claims. shall.

On the other hand, various embodiments of the present invention may be combined with any other embodiments unless clearly indicated to the contrary. Any feature indicated as particularly preferred or advantageous may be combined with any other feature and features indicated as preferred or advantageous. Hereinafter, embodiments of the present invention and effects thereof will be described with reference to the accompanying drawings.

An electrochemical device according to an embodiment of the present invention includes an ion storage layer capable of storing ions; and an active layer whose conductivity varies depending on the ion concentration of the dopant material. Ions of the dopant material are inserted or extracted from the active layer into the ion storage layer according to an external electric field to operate the electrochemical device.

The ion storage layer is a layer capable of storing ions, amorphous silicon (a-Si), titanium dioxide (TiO ₂ ), graphite, carbon (carbon), lithium (Li), tungsten oxide (WO ₃ ), Carbon nanotubes (CNT), molybdenum oxide (MoO _x ), tungsten selenium (WSe _x ), vanadium oxide (VO ₂ ) is a single layer formed including any one or more selected from the group consisting of, or the single layer is at least It may be a multi-layer provided with two or more layers.

The thickness of the ion storage layer may be formed in a range of 1 nm to 500 nm, but is not limited thereto and may be formed according to the characteristics of the device.

The active layer is a layer formed of a compound containing a dopant material, which is a material contributing to changing the conductivity, and the conductivity may be controlled according to the amount of the dopant material in the active layer. That is, when the dopant material in the active layer is moved and stored in the ion storage layer, the overall conductivity of the device increases (resistance decreases), and in the opposite operation, the conductivity decreases (resistance increases).

The dopant material includes at least one selected from the group consisting of Li, H, Cu, Ag, Na, Mg, Fe, Ni, Ti, Te, O and Ca, and the compound is an oxide, sulfide, phosphate and any one or more selected from the group consisting of silicates. The active layer may also be a single layer or a multilayer including at least two or more single layers.

The thickness of the active layer may be formed in a range of 1 nm to 500 nm, but is not limited thereto and may be formed according to the characteristics of the device.

When the electrochemical device according to the present invention is used in a memory device, an ion storage layer may be formed on the active layer, and an electrode may be provided on the ion storage layer. For example, it may be composed of a lower electrode, an active layer, an ion storage layer, and an upper electrode.

When the electrochemical device according to the present invention is used in an energy storage device such as a battery, the active layer may be applied as an anode and the ion storage layer may be applied as an anode, provided between the ion storage layer and the active layer It may further include an ion-barrier layer (electrolyte layer) that prevents ions from moving when an external electric field is applied, and suppresses self-movement of ions when an external electric field is not applied and prevents an electrical short between the active layer and the ion storage layer. By forming a barrier layer against dopant ions between the active layer, whose resistance varies according to the amount of dopant ions, and the ion-storing layer, self-movement of ions can be suppressed, thereby improving device stability.

The ion-barrier layer not only serves as an electrolyte in which ions of the dopant material can move, but also has a high electrical resistivity. The ion-barrier layer includes at least one selected from the group consisting of LiPO, LiPON, LiPOSe, SiO ₂ , TiN and TiO _{2 .} Preferably, it is good to include any one or more selected from the group consisting of LiPO, LiPON and LiPOSe.

In addition, it can be applied as a switching device by changing the resistance to a high resistance state (HRS) and a low resistance state (LRS).

The ion storage layer and the active layer according to the present invention are formed by a deposition method such as sputtering, pulsed laser deposition, chemical vapor deposition, atomic layer deposition or molecular beam epitaxy deposition, and the active layer is an active layer with controlled porosity. control porosity. In a low vacuum state, there are few collisions between the deposited particles and atmospheric particles, so the deposited particles contribute to film growth without losing energy. As a result, an excellent film, a dense film can be grown. On the other hand, in a high vacuum state, there are many collisions between the deposited particles and atmospheric particles, so the deposited particles lose energy and contribute to film growth. As a result, a porous membrane is formed.

In the case of forming a porous thin film by depositing under a mixed gas atmosphere consisting of nitrogen gas and inert gas, rather than controlling the vacuum level when forming the active layer, there is a possibility that the porous thin film is deposited in a form containing impurity components such as nitride, not pure components. It is good to control the porosity of the active layer. As the porosity of the active layer increases, a large amount of diffusion path is provided, so the amount of moving ions increases, and the conductivity of the device can be controlled to be changed more rapidly by an external electric pulse. Conversely, as the porosity of the active layer decreases, the diffusion path decreases, so the amount of moving ions decreases, and the conductivity of the device can be controlled to be changed more slowly by an external electric pulse.

As such, as the porosity of the membrane increases, the behavior of ion migration increases and the rapid behavior is expected to be due to the condition that ions are easy to move because there are many diffusion paths in the case of a high porosity membrane. Therefore, the behavior of ions can be easily and effectively controlled through porosity control. It also shows that the properties and performance of the device can be easily controlled by controlling the rapid movement of many ions through porosity control.

When the active layer is deposited, the porosity is controlled by adjusting the vacuum degree within the range of 1 to 100 mTorr, and a difference in ion behavior may be caused according to the controlled porosity.

Example (1)

A molybdenum film was formed by sputtering deposition at vacuum degrees of 5 mTorr, 10 mTorr, and 15 mTorr, respectively. An image of the top of the deposited film is shown in FIG. 1 . As shown in FIG. 1 , it can be seen that the higher the vacuum state, the more porous film is formed, and it can be seen that the porosity of the film can be controlled through the pressure (vacuum degree control) during the process.

Example (2)

A resistance-variable memory device based on lithium (Li) ions was manufactured. The structure is as shown in FIG. 2 . The fabricated resistance change-based memory device can change the resistance state of the device according to the concentration of lithium ions in the active layer. More specifically, it has a structure of a lower electrode (Cr) / an active layer (LiCoO ₂ ) / an ion storage layer (a-Si) / an upper electrode (TiN). All of the composing films were manufactured using an RF-sputter device.

In the case of the lower electrode (Cr), a film was formed in an atmosphere of 100W (power), 10 mTorr, and Ar, and in _{the case of the active layer (LiCoO 2} ), the porosity control method _{for the LiCoO 2} layer was applied to check the difference in ion behavior according to the porosity control. became _{In detail, three types of devices containing LiCoO 2} deposited in a vacuum state of 10 mTorr, 30 mTorr, and 50 mTorr were fabricated (using 100W power). The ion storage layer (a-Si) was deposited in an atmosphere of 100 W, 5 m Torr, and Ar. The upper electrode (TiN) was deposited in an Ar atmosphere at 120 W, 20 m Torr.

When the ion storage layer was deposited, three types of devices manufactured by controlling the porosity by setting the vacuum degree to 10 mTorr, 30 mTorr, and 50 mTorr were prepared as Comparative Examples.

Experimental example

The difference in ion behavior according to the porosity of the active layer in the fabricated resistance-variable memory device and the corresponding change in the characteristics of the memory device were measured. As shown in FIG. 3 , it was confirmed that the peak current caused by the movement of ions showed different behavior according to the difference in porosity. As the amount of moving ions increases, the peak current increases. As a result, as the density of the active layer increases (Dense), the observed peak current shows a very small value of several hundred pico amps, indicating that the movement of ions is small. On the other hand, as the porosity increases (porous), it can be seen that the peak current is remarkably increased, which shows that the amount of moving ions is increased. Also, the higher the density, the more insulating behavior, which is related to the CV analysis result.

On the other hand, when the porosity of the ion storage layer was controlled, similar CV behavior was shown as shown in FIG. 4 , but the IV curve under the same bias showed a decreased current level as the density of the a-Si layer increased. This means that Li ions can migrate under the same bias, but the amount of intercalated Li ions decreases as the density of the a-Si layer increases. This appears to be due to the morphological change at the interface between the a-Si and LiCoO _{2 layers.} From these results, it can be interpreted that the porosity of the anode and the cathode significantly affects the operating voltage and the amount of mobile Li ions.

In addition, the results of adjusting the resistance-variable memory device characteristics and performance by controlling the ion behavior according to the change in porosity of the active layer are shown in FIG. 5 . As shown in FIG. 5 , it can be confirmed that the conductivity of the device is controlled to be changed more rapidly by an external electric pulse by increasing the porosity. This is due to the rapid movement of many ions. These results show that the properties and performance of the device can be easily controlled by controlling the porosity.

Features, structures, effects, etc. exemplified in each of the above-described embodiments may be combined or modified for other embodiments by those of ordinary skill in the art to which the embodiments belong. Therefore, the contents related to such combinations and modifications should be interpreted as being included in the scope of the present invention.

Claims (8)

an ion storage layer capable of storing ions; and
Including; an active layer whose conductivity varies depending on the ion concentration of the dopant material;
The active layer is an electrochemical device whose porosity is controlled by the degree of vacuum during deposition.
According to claim 1,
The active layer is a layer formed of a compound containing a dopant material,
The dopant material includes any one or more selected from the group consisting of Li, H, Cu, Ag, Na, Mg, Fe, Ni, Ti, Te, O and Ca,
The compound is an electrochemical device comprising at least one selected from the group consisting of oxides, sulfides, phosphates and silicates.
According to claim 1,
The ion storage layer is amorphous silicon (a-Si), titanium dioxide (TiO ₂ ), graphite (graphite), carbon (carbon), lithium (Li), tungsten oxide (WO ₃ ), carbon nanotubes (CNT), oxide Molybdenum (MoO _x ), tungsten selenium (WSe _x ), vanadium oxide (VO ₂ ) Electrochemical device comprising any one or more selected from the group consisting of.
According to claim 1,
The active layer is an electrochemical device, characterized in that the porosity is controlled by controlling the vacuum degree within the range of 1 to 100 mTorr during deposition.
An energy storage device comprising the electrochemical device according to any one of claims 1 to 4.
A memory device comprising the electrochemical device according to any one of claims 1 to 4.
forming an ion storage layer capable of storing ions; and
Including; forming an active layer whose conductivity varies depending on the ion concentration of the dopant material;
The step of forming the active layer is formed by a deposition method, and the method of manufacturing an electrochemical device is a step of controlling porosity by a degree of vacuum during deposition.
8. The method of claim 7,
The step of forming the active layer is deposited using sputtering, pulsed laser deposition, chemical vapor deposition, atomic layer deposition, or molecular beam epitaxial deposition, and the vacuum degree is adjusted within the range of 1 to 100 mTorr during deposition. Electricity, characterized in that A method of manufacturing a chemical device.

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