KR101394743B1 - Lithium-ion capacitor and manufacturing method of therof - Google Patents

Abstract

The present invention relates to an energy storage device, and more particularly, to a lithium ion capacitor and a lithium ion capacitor, which are manufactured by simplifying a process step by adding a lithium-based metal oxide to a positive electrode by a formation (battery activation) And a manufacturing method thereof.

Description

FIELD OF THE INVENTION [0001] The present invention relates to a lithium ion capacitor,

The present invention relates to an energy storage device, and more particularly, to a lithium ion capacitor to which a lithium-based metal oxide is added to a positive electrode of a lithium ion capacitor.

In the modern society, as the electric and electronic fields have grown to a high level, the energy storage field has also developed remarkably. Particularly, development of a secondary battery capable of converting electric energy into chemical energy and storing it and converting it into electrical energy when necessary is actively developed, but currently developed secondary batteries do not satisfy high output characteristics or rapid charge / discharge characteristics .

Therefore, recently, electrochemical capacitors have been attracting attention as energy storage devices having these characteristics.

These electrochemical capacitors are typically electric double-layer capacitors (EDLC) and pseudocapacitors. Recently, hybrid capacitors have been newly proposed. The hybrid capacitor uses an active material electrode which is different from the charging and discharging mechanism for the positive electrode and the negative electrode. These hybrid capacitors have the disadvantage of being difficult to design pole plates, but they are characterized by higher energy density than other capacitors. In particular, when a material used for a lithium secondary battery is applied, it exhibits a larger capacity than a conventional electric double layer capacitor and has a characteristic of having a high energy density.

Among the hybrid capacitors presented so far, lithium-ion capacitors (LiC) have the advantage that their energy density is higher than other hybrid capacitors because of their high discharge capacity and wide charging / discharging voltage range. To make a lithium-ion capacitor, a pre-doping process, in which lithium is inserted into the cathode of the capacitor, must be performed. The pre-doping method known so far involves electrochemically reacting a lithium metal with a cathode Lithium was inserted into the negative electrode.

This method is the simplest method of inserting lithium into the cathode, but has the following disadvantages. First, the other capacitors are made up of two electrodes, but the lithium ion capacitor should consist of three electrodes. Second, when the distance between a specific point of the cathode and the lithium metal electrode is different, the lithium doping in the cathode is not uniform. Third, it is difficult to sequentially laminate the electrodes with a separator or the like and then wind it into a cylindrical shape, or sequentially laminate a plurality of electrodes and separators. Fourth, there are restrictions on the form of capacitors.

To solve these drawbacks, Korean Patent Registration No. 10-1085359 (registered on Nov. 15, 2011) discloses a method of using a cathode of a lithium ion capacitor as a thin film lithium metal.

However, since lithium has a low melting point and high reactivity, it is very difficult to produce a thin film, and when a lithium metal is applied to a capacitor, stability of printing due to external impact is very low.

The present invention provides a lithium ion capacitor manufactured by simplifying a structure by adding a lithium-based metal oxide to a positive electrode and a method of manufacturing the same.

The technical objects to be achieved by the present invention are not limited to the above-mentioned technical problems.

According to an aspect of the present invention, there is provided a capacitor including a positive electrode and a negative electrode, wherein a lithium-based metal oxide may be added to the positive electrode.

Specifically, the lithium-based metal oxide may be Li ₂ Cu _1-y Zn _y O ₂ (0? _Y? 0.1).

The lithium-based metal oxide may be added in a weight ratio (wt%) of 0.05 to 3 g based on 1 g of the weight of the negative electrode.

An electrode including a lithium ion capacitor having the above characteristics can be manufactured.

According to another aspect of the present invention, there is provided a method of manufacturing a lithium ion capacitor, comprising the steps of preparing a lithium-based metal oxide, mixing the lithium-based metal oxide with activated carbon to produce a positive electrode, An electrode manufacturing step of selectively manufacturing a cathode electrode, and a step of fabricating a capacitor including the anode electrode and the cathode electrode manufactured as described above.

Specifically, the lithium-based metal oxide may be Li ₂ Cu _1-y Zn _y O ₂ (0? _Y? 0.1).

In the electrode manufacturing step, the anode electrode may be manufactured with a weight of 0.05 to 10 g based on 1 g of the cathode electrode.

The lithium-based metal oxide may be added to the positive electrode at a weight ratio (wt%) of 0.05 to 3 g based on 1 g of the weight of the negative electrode.

The addition ratio of the lithium-based metal oxide can be calculated by the following relational expression.

Relation

The initial charging capacity of the anode and the lithium-based metal oxide is the capacity when the half-cell is first fabricated and then the voltage is raised to the high potential with reference to 3 V. The initial discharge capacity of the cathode is 3 V It is the capacity when the voltage is lowered to the low potential as a reference.

An electrode including the lithium ion capacitor manufactured by the above method can be manufactured.

INDUSTRIAL APPLICABILITY As described above, according to the lithium ion capacitor of the present invention and the method of manufacturing the same, a lithium ion capacitor in which a lithium-based metal oxide is added to an anode is formed by a formation (battery activation) method other than a pre-doping method, can do. In addition, since the lithium ion capacitor can be fabricated with two electrodes, it is possible to reduce the limitation of the manufacturing form.

FIG. 1 is a flowchart showing a method of manufacturing a lithium ion capacitor according to the present invention in order.
FIG. 2 shows XRD analysis results of Li ₂ CuO ₂ and Li ₂ Cu _0.9 Zn _0.1 O ₂ associated with the present invention.
FIG. 3 is a graph showing changes in charging / discharging curves of a half-cell manufactured using artificial graphite in accordance with the present invention. FIG.
FIG. 4 is a graph showing changes in charging / discharging curves of a half-cell manufactured using activated carbon according to the present invention in response to a voltage change. FIG.
FIG. 5 is a graph showing changes in initial charging / discharging curves according to voltage changes of each half-cell manufactured using Li ₂ CuO ₂ and Li ₂ Cu _0.9 Zn _0.1 O _{2 according} to the present invention.
FIG. 6 is a graph showing a change in discharge capacity according to the number of cycles of each half-cell manufactured using Li ₂ CuO ₂ and Li ₂ Cu _0.9 Zn _0.1 O _{2 according} to the present invention.
FIG. 7 is a graph showing a voltage change with time for showing a fomation process of a pouch-type battery fabricated by the formation (cell activation) process according to the first embodiment of the present invention.
FIG. 8 is a graph showing changes in voltage with time during five cycles after the formation (cell activation) of the pouch-shaped battery according to the first embodiment of the present invention.
FIG. 9 is a graph showing voltage changes with time for showing the fomation process of a pouch-type battery fabricated by the formation (cell activation) process according to the second embodiment of the present invention.
10 is a graph showing voltage changes with time for showing a free-doping process of a pouch-type battery manufactured by a pre-doping process of Comparative Example 1 of the present invention.
FIG. 11 is a graph showing changes in voltage with time for five cycles after free-doping of the pouch-type battery of Comparative Example 1 of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same components are denoted by the same reference symbols whenever possible. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail.

The lithium ion capacitor of the present invention comprises a positive electrode and a negative electrode, and a lithium-based metal oxide is added to the positive electrode. Specifically, the lithium-based metal oxide is Li ₂ Cu _{1 -y} Zn _y O ₂ (0? _Y? 0.1), for example, Li ₂ CuO ₂ or Li ₂ Cu _{0 .9} Zn _{0 .1} O ₂ .

The lithium-based metal oxide is preferably added in a weight ratio (wt%) of 0.05 to 3 g based on 1 g of the weight of the anode to the anode.

The lithium-ion capacitor to which the lithium-based metal oxide is added is not used as a capacitor through a free-doping process, and is used as a capacitor through a fomation (battery activation) process. Therefore, the complex process of reacting the conventional cathode electrode with the lithium metal electrode, reacting the anode electrode with the lithium metal electrode, and then reacting the cathode electrode with the lithium metal electrode is not performed. If necessary, it is possible to fabricate such a structure that only two electrodes, that is, an anode and a cathode, are formed, thereby reducing the limitation of the manufacturing form.

It is also preferable to control the charging voltage to not exceed 4.4 V at the time of fomation (battery activation) of the lithium ion capacitor manufactured as described above. If the charge voltage exceeds 4.4 V, activated carbon (AC) used as a positive electrode material of the lithium ion capacitor (LiC) may excessively react (or side reaction) with the electrolyte and adversely affect the negative electrode.

In addition, a variety of lithium ion capacitors (LiC) can be manufactured using the electrodes manufactured in this way. Electrodes are formed by applying or bonding an electrode material to a current collector as in the case of a general capacitor, And an electrolyte film or a separator are successively laminated and then rolled and pressed, or they may be sequentially laminated to form a cell.

At this time, as a cathode material for manufacturing a lithium ion capacitor, it is preferable to use a material capable of adsorbing or desorbing an anion of a salt in the electrolyte solution. More specifically, the porous activated carbon or activated carbon fiber having a specific surface area of 800 to 3000 m ² / g, the non-porous activated carbon having a specific surface area of 1000 m ² / g or less, the carbon nanotube or the carbon nano- Fibers and the like can be used.

In addition, as a negative electrode material for manufacturing a lithium ion capacitor, it is preferable to use a material capable of inserting and desorbing lithium. More specifically, graphitized carbon, isotropic or anisotropically carbonized carbon, silicon or oxidized silicon, metal-silicon alloys, metal oxides, lithium-based metal nitrides and the like can be used.

The organic electrolyte for preparing the lithium ion capacitor may be one or more kinds selected from the group consisting of acetonitrile (AN), ethylene carbonate (EC), propylene carbonate (PC), diethylene carbonate (DEC) and dimethyl carbonate selecting _{TEABF 4 (tetraethylammonium tetrafluorborate), TEMABF} 4 (triethylmethylammonium tetrafluorborate), LiClO 4 (lithium perchlorate), LiPF 6 (lithium hexafluorophosphate), LiAsF 6 (lithium hexafluoroarsenate) in the organic solvent and the organic solvent blend, and LiBF ₄ (lithium tetrafluoroborate), or a mixture of two or more kinds of salts. This electrolyte solution can be impregnated or coated on the separation membrane. Further, additives such as vinylene carbonate (VC) and biphenyl (BP) may be used to prevent side reactions or overcharging of the cathode.

FIG. 1 is a flowchart showing a method of manufacturing a lithium ion capacitor according to the present invention in order. Referring to the flowchart, the lithium ion capacitor includes a step of preparing a lithium-based metal oxide (S10), a step of manufacturing an anode electrode and a cathode electrode (S20), and a step of fabricating a capacitor with the electrodes ).

Specifically, a lithium-based metal oxide is first prepared. (S10) Here, the lithium-based metal oxide is Li ₂ Cu _1-y Zn _y O ₂ (0? _Y? 0.1) It is advantageous to carry out the invention to selectively use oxides. First, it must have a high initial charge capacity and a low initial discharge capacity. Second, when lithium is used as the reference electrode (Li / Li +), it should be operated at a voltage less than 4.4V when charged. Third, when recharging after the initial discharge, metal oxide should be difficult to insert lithium. Fourth, after the lithium is desorbed, the metal oxide should not react with the activated carbon (AC) of the lithium ion capacitor (LiC) or the separator or current collector. Fifth, synthesis should be possible in air. A specific example that satisfies this characteristic is Li ₂ CuO ₂ or Li ₂ Cu _0.9 Zn _0.1 O ₂ .

Li ₂ CuO ₂ can be prepared by solid phase synthesis using LiOHH ₂ O and Cu (NO ₃ ) (OH) ₃ as a sample. Specifically, the sample is mixed with a mortar and heated at 800 ° C. for 5 hours Can be manufactured. Li ₂ Cu 0.9 Zn _{0 .1} O ₂ The Li ₂ Cu _{0 .9} Zn _{0 .1} O _{2 can} also be prepared by a solid phase synthesis method using a mixture of LiOHH ₂ O and Cu (NO ₃ ) (OH) ₃ and ZnO as a sample. Specifically, And mixing them in a mortar and then heat-treating them at 800 ° C for 5 hours.

The Li ₂ CuO ₂ and Li ₂ Cu _0.9 Zn _0.1 O ₂ thus produced can be confirmed by the XRD results of FIG. Referring to FIG. 2, the result of XRD analysis shows that Li ₂ CuO _{2 produced} is JCDPDS card No. 38-0917, which is a Li ₂ CuO ₂ compound. The Li ₂ Cu _0.9 Zn _0.1 O _{2 produced} is Li ₂ CuO ₂ and ZnO are mixed.

Next, the anode electrode and the cathode electrode are respectively fabricated. (S20)

At first, at least one of natural graphite and artificial graphite is selected as a cathode electrode and made into a cathode electrode.

As an example, a negative electrode is fabricated using artificial graphite particles (for example, MCMB 1028 (manufactured by Osaka Gas Co., Ltd.)), which is used as a negative electrode and is bonded to a Cu-mesh. Concretely, the cathode electrode is composed of 85 wt% of artificial graphite particles (for example, MCMB 1028 (manufactured by Osaka Gas Co., Ltd.) as a cathode material, 10 wt% of Denka black (manufactured by Denka) as a conductive agent, and PTFE (polytetrafluoroethylene; Polytetrafluoroethylene) was added to the electrode to prepare an electrode. The resultant was vacuum-dried at about 80 ° C for 10 hours, and used as a cathode electrode.

On the other hand, the anode electrode is produced by mixing a lithium-based metal oxide and activated carbon to form a cathode electrode.

As an example, a certain amount of activated carbon (for example, MSP 20) as a cathode material and a lithium metal oxide prepared in a previous process are mixed and an anode electrode is prepared and bonded to an Al-mesh. Such a lithium-based metal oxide is Li ₂ Cu _{1 - y} Zn _y O ₂ (0? _Y? 0.1), for example, Li ₂ CuO ₂ or Li ₂ Cu _0.9 Zn _0.1 O ₂ . Specifically, the anode electrode was prepared by mixing 85 wt% of a mixture prepared by adding Li ₂ CuO ₂ or Li ₂ Cu _{0 .9} Zn _{0 .1} O ₂ to activated carbon, 10 wt% of a conductive agent, Denka black (manufactured by Denka) Polytetrafluoroethylene (Polytetrafluoroethylene) was added to the electrode to prepare an electrode, which was vacuum-dried at about 80 ° C for 10 hours.

At this time, Li ₂ CuO ₂ or Li ₂ Cu _{0 .9} Zn _{0 .1} O ₂ , which is a lithium metal oxide, is added to the anode electrode at a weight ratio (wt%) of 0.05 to 3 g based on 1 g of the cathode electrode weight . More specifically, the addition ratio of the lithium-based metal oxide added to the anode electrode can be calculated by the following relational expression.

Relation

Here, the initial charging capacity of the anode electrode and the lithium-based metal oxide is the capacity when the half-cell is first fabricated and then the voltage is raised to the high potential with reference to 3 V. The initial discharge capacity of the cathode is 3 V Is the capacity at the time when the voltage at the low potential is lowered.

In order to confirm the addition ratio of the metal oxide in the above relational expression, the step of confirming the initial discharge capacity of the cathode for use as a battery, the initial charge capacity of the anode, and the initial charge capacity of the metal oxide may be preceded by have.

The initial discharge capacity of the negative electrode can be confirmed by examining the charge / discharge change after manufacturing a half cell using an anode material for a lithium ion capacitor (eg, MCBC 1028). Specifically, the half-cell is prepared by adding 85 wt% of an anode material (e.g., MCBC 1028), 10 wt% of Denka black as a conductive agent, and 5 wt% of PTFE (polytetrafluoroethylene) After vacuum drying at about 80 ° C for 10 hours, it is used as a positive electrode and lithium metal is used as a negative electrode. In addition, the electrolyte used was EC / DEC (v: v = 1: 1) in which 1 M of LiPF ₆ was dissolved and a polypropylene system was used as a separator. 3 shows the charge / discharge curve change according to the voltage change when a current is applied to the thus fabricated half-cell at 20 ° C at 20 mA / g, whereby the initial discharge capacity of the negative electrode material (for example, MCMB 1028) / g, and the initial charging capacity is about 250 mAh / g.

The initial charging capacity of the anode can be confirmed by preparing a half-cell using a cathode material for lithium ion capacitor (eg MSP 20) and examining the charge-discharge changes. Specifically, the half-cell is prepared by adding 85 wt% of a cathode material (for example, MSP 20), 10 wt% of Denka black as a conductive agent, and 5 wt% of PTFE (polytetrafluoroethylene) After vacuum drying at about 80 ° C for 10 hours, it is used as a positive electrode and lithium metal is used as a negative electrode. In addition, the electrolyte used was EC / DEC (v: v = 1: 1) in which 1 M of LiPF ₆ was dissolved and a polypropylene system was used as a separator. FIG. 4 shows changes in charge and discharge curves according to a voltage change when a current of 20 mA / g was applied to the thus fabricated half-cell at a temperature range of 2.0 to 4.31 V at 20 ° C, ) Is about 50 mAh / g, and the initial discharge capacity is about 95 mAh / g.

The initial charge capacity of the metal oxide is determined by using a lithium-based metal oxide (Li ₂ Cu _1-y Zn _y O ₂ (0? _Y? 0.1); Li ₂ CuO ₂ or Li ₂ Cu _0.9 Zn _0.1 O ₂ ) , And then checking the change of charge and discharge. Specifically, the half-cell is manufactured by using an electrode comprising 85 wt% of lithium metal oxide, 10 wt% of Denka black as a conductive agent, and 5 wt% of PTFE (polytetrafluoroethylene) as a bonding agent, After vacuum drying for 10 hours, it is used as a positive electrode, and lithium metal is used as a negative electrode. In addition, the electrolyte used was EC / DEC (v: v = 1: 1) in which 1 M of LiPF ₆ was dissolved and a polypropylene system was used as a separator. FIG. 5 shows the initial charging / discharging curves according to the voltage change when a current of 20 mA / g was applied in the voltage range of 1.8 to 4.31 V at 20.degree. C., ₂ The initial charge capacity of CuO ₂ is about 330 mAh / g, and the initial charge capacity of the lithium metal oxide Li ₂ Cu _0.9 Zn _0.1 O ₂ is about 260 mAh / g. In addition, referring to FIG. 6, the change in discharge capacity according to the number of cycles of the half-cell fabricated as described above can be observed to decrease rapidly as the cycle progresses. Therefore, it can be concluded that, when a full cell of a lithium ion capacitor (LiC) is fabricated, the cell is stabilized as the cycle progresses.

On the other hand, Li ₂ Cu _1-y Zn _y O ₂ (0? _Y? 0.1), which is a lithium metal oxide, is used as an additive for providing lithium to the cathode at the time of formation, Is not added in order to suppress. Further, in Li ₂ Cu _1-y Zn _y O ₂ (0? _Y? 0.1), impurities may increase or form a different crystal structure with an increase in the amount of Zn added, but this does not greatly affect the present invention. In addition, the initial charge capacity can be decreased while the initial charge capacity is reduced as the addition amount of Zn increases in Li ₂ Cu _1-y Zn _y O ₂ (0? _Y? 0.1). In addition, Li ₂ Cu _1-y Zn _y O ₂ (0? _Y? 0.1) is slowly decomposed in the air after it is synthesized. To prevent this, Li ₂ Cu _{1 - y} Zn _y O ₂ ) May be synthesized and then the surface modification process may be added.

Thereafter, a capacitor including a cathode electrode and a cathode electrode manufactured according to the above-described process is manufactured (S30)

At this time, the anode electrode for constituting the capacitor is manufactured with a weight of 0.05 to 10 g based on 1 g of the cathode electrode weight. That is, when the weight of the anode electrode is less than 0.05 g, the capacity is poor. When the weight of the anode electrode is more than 10 g, the working voltage range of the cathode is excessively widened Therefore, the capacity is rapidly reduced.

Here, a lithium-based metal oxide (Li ₂ Cu _{1 - y} Zn _y O ₂ (0? _Y? 0.1)) is added to the anode electrode at a weight ratio (wt%) of 0.05 to 3 g based on 1 g of the weight of the cathode electrode. If the ratio of the lithium-based metal oxide added to the anode electrode is less than 0.05 g, lithium is not properly inserted into the cathode electrode. If the ratio is more than 3 g, lithium is excessively inserted into the cathode electrode, resulting in problems such as stability.

The organic electrolyte for preparing the lithium ion capacitor may be one or more kinds selected from the group consisting of acetonitrile (AN), ethylene carbonate (EC), propylene carbonate (PC), diethylene carbonate (DEC) and dimethyl carbonate selecting _{TEABF 4 (tetraethylammonium tetrafluorborate), TEMABF} 4 (triethylmethylammonium tetrafluorborate), LiClO 4 (lithium perchlorate), LiPF 6 (lithium hexafluorophosphate), LiAsF 6 (lithium hexafluoroarsenate) in the organic solvent and the organic solvent mixture, and LiBF ₄ (lithium tetrafluoroborate), or a mixture of two or more kinds of salts. This electrolyte solution can be impregnated or coated on the separation membrane. Further, additives such as vinylene carbonate (VC) and biphenyl (BP) may be used to prevent side reactions or overcharging of the cathode.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

division Anode electrode Cathode electrode Manufacturing method Manufacturing form Example 1 MSP 20 + Li ₂ CuO ₂ MCMB 1028 fomation Pouch type battery Example 2 MSP 20 + Li ₂ Cu _0.9 Zn _0.1 O ₂ MCMB 1028 fomation Coin-type battery Comparative Example 1 MSP 20 MCMB 1028 free-dopping Pouch type battery

≪ Example 1 >

Li ₂ CuO ₂ was prepared by solid phase synthesis using LiOHH ₂ O and Cu (NO ₃ ) (OH) ₃ as a sample, and Li ₂ CuO ₂ was added by the above-described method to prepare a lithium ion capacitor. In this case, the weight ratio of the anode electrode to the cathode electrode is 2.5: 1, which is the ratio of the initial discharge capacity of MSP 20 to the initial charge capacity of MCMB 1028, wherein the ratio of the amount of Li ₂ CuO ₂ added to the anode electrode is 0.77.

The negative electrode was fabricated by the above-described method using the negative electrode material MCMB 1028 and bonded to a collector Cu-mesh. The anode electrode was prepared by mixing MSP 20 and Li ₂ CuO ₂ in a quantitative manner, and was then bonded to an Al-mesh current collector.

The width of all the electrodes was 5 × 5 cm 2, and a pouch type cell was fabricated.

At this time, EC / DEC (v: v = 1: 1) in which 1 M of LiPF ₆ was dissolved was used as an electrolyte, and a polypropylene system was used as a separator.

The formation process is shown in FIG. 7 when a current is applied to the lithium ion capacitor (LiC) manufactured by the above method at 20 DEG C at 20 mA / g, and the voltage change over time during 5 cycles after the formation is shown in FIG. Respectively.

≪ Example 2 >

Li ₂ Cu _{0 .9} Zn _{0 .1} O ₂ was prepared by a solid phase synthesis method using LiOHH ₂ O, Cu (NO ₃ ) (OH) ₃ and ZnO as a sample, _Thereby preparing a lithium ion capacitor to which Li ₂ Cu _0.9 Zn _0.1 O ₂ was added. In this case, the weight ratio of the anode electrode to the cathode electrode is 2.5: 1, which is the ratio of the initial discharge capacity of MSP 20 to the initial charging capacity of MCMB 1028, wherein the ratio of the amount of Li ₂ Cu _0.9 Zn _0.1 O ₂ added to the anode electrode 0.98.

The negative electrode was fabricated by the above-described method using the negative electrode material MCMB 1028 and bonded to a collector Cu-mesh. The anode electrode was prepared by mixing MSP 20 and Li ₂ Cu _0.9 Zn _0.1 O ₂ in a quantitative manner, and then bonded to Al-mesh as a current collector.

The circumference of all electrodes was 15Φ and a coin type battery (2032 type) was fabricated.

The electrolytic solution used was EC / DEC (v: v = 1: 1) in which 1M of LiPF ₆ was dissolved and a polypropylene system was used as a separator.

The formation process is shown in FIG. 9 when a current is applied to a lithium ion capacitor (LiC) manufactured by the above method at 20 DEG C at 20 mA / g.

≪ Comparative Example 1 &

(MSP 20) and an anode material (for example, MCMB 1028) without adding a lithium-based metal oxide to prepare a battery by a pre-doping process, and using the lithium-based metal oxide as a lithium ion capacitor, Respectively. At this time, the weight ratio of the anode electrode to the cathode electrode is 2.5: 1, which is the ratio of the initial discharge capacity of MSP 20 to the initial charge capacity of MCMB 1028.

The negative electrode was fabricated by the above-described method using the negative electrode material MCMB 1028 and bonded to a collector Cu-mesh. The anode electrode was fabricated by the method described above using MSP 20 and bonded to the collector Al-mesh. In addition, an electrode having lithium metal bonded to a Cu-mesh for lithium pre-doping was prepared.

The width of all the electrodes was 5 × 5 cm 2, and a pouch type cell was fabricated.

The electrolytic solution used was EC / DEC (v: v = 1: 1) in which 1M of LiPF ₆ was dissolved and a polypropylene system was used as a separator.

The pre-doping process is shown in FIG. 10 when a current is applied to a lithium ion capacitor (LiC) manufactured by the above method at 20 ° C at 20 mA / g. The voltage change over time during five cycles after pre- Is shown in Fig.

The discharge capacities (mAh / g) according to 1 to 5 cycles of the lithium ion capacitors prepared in Example 1 and Comparative Example 1 were summarized in Table 2 below.

Number of cycles Example 1 Comparative Example 1 One 60.91 61.10 2 60.24 57.71 3 58.14 58.01 4 56.05 56.21 5 53.00 56.54

Thus, it can be seen that there is no significant difference in the discharge capacity according to the cycle number change of Example 1 produced by the fomation process and Comparative Example 1 produced by the general free-doping process by adding the lithium metal oxide.

Rather, the process steps can be simplified, and it is advantageous to fabricate a lithium ion capacitor composed of two electrodes, which can reduce the limitation of the manufacturing form.

The lithium ion capacitor and the manufacturing method thereof are not limited to the configuration and operation of the embodiments described above. The embodiments may be configured so that all or some of the embodiments may be selectively combined so that various modifications may be made.

Claims (10)

1. A capacitor comprising an anode and a cathode, wherein a lithium-based metal oxide is added to the anode at an addition ratio calculated by the following relationship.

Relation

The initial charging capacity of the anode and the lithium-based metal oxide is the capacity when the half-cell is first fabricated and then the voltage is raised to the high potential with reference to 3 V. The initial discharge capacity of the cathode is 3 V It is the capacity when the voltage is lowered to the low potential as a reference.
The method according to claim 1,
Wherein the lithium-based metal oxide is Li ₂ Cu _{1 - y} Zn _y O ₂ (0? _Y? 0.1).
The method according to claim 1,
Wherein the lithium-based metal oxide is added in a weight ratio (wt%) of 0.05 to 3 g based on 1 g of the weight of the negative electrode.
Preparing a lithium-based metal oxide;
Preparing an anode electrode by mixing the lithium-based metal oxide with activated carbon at an addition ratio calculated by the following relationship, and selecting at least one of natural graphite and artificial graphite to produce a cathode electrode; And
And fabricating a capacitor including the positive electrode and the negative electrode manufactured as described above.

Relation

The initial charging capacity of the anode and the lithium-based metal oxide is the capacity when the half-cell is first fabricated and then the voltage is raised to the high potential with reference to 3 V. The initial discharge capacity of the cathode is 3 V It is the capacity when the voltage is lowered to the low potential as a reference.
The method of claim 4,
Wherein the lithium-based metal oxide is Li ₂ Cu _1-y Zn _y O ₂ (0? _Y? 0.1).
The method of claim 5,
In the electrode manufacturing step,
Wherein the anode electrode is manufactured with a weight of 0.05 to 10 g based on 1 g of the weight of the cathode electrode.
The method of claim 5,
Wherein the lithium-based metal oxide is added to the positive electrode at a weight ratio (wt%) of 0.05 to 3 g based on 1 g of the weight of the negative electrode.
delete A battery comprising a lithium ion capacitor having the features of any one of claims 1 to 3.
A battery comprising a lithium ion capacitor produced by the method of any one of claims 4 to 7.

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