KR102168789B1 - Lithium cobalt oxide-carbon composite for positive active material for lithium ion capacitor, positive active material comprising the same, lithium ion capacitor comprising the same, and preparation method thereof - Google Patents

Abstract

The present invention relates to a lithium cobalt oxide-carbon composite for a lithium ion capacitor, a positive electrode active material including the same, a lithium ion capacitor including the same, and a method of manufacturing the same, and a lithium cobalt oxide for a lithium ion capacitor according to an embodiment of the present invention- The carbon composite includes a lithium metal compound and carbon, and is represented by the following formula.
[Chemical Formula]
Li _6-x CoO ₄ ·C
In the above formula, 0≤x≤4.

Description

Lithium cobalt oxide-carbon composite for lithium ion capacitors, positive electrode active material containing the same, lithium ion capacitor containing the same, and manufacturing method thereof {LITHIUM COBALT OXIDE-CARBON COMPOSITE FOR POSITIVE ACTIVE MATERIAL FOR LITHIUM ION CAPACITOR, POSITIVE ACTIVE MATERIAL COMPRISING THE SAME , LITHIUM ION CAPACITOR COMPRISING THE SAME, AND PREPARATION METHOD THEREOF}

The present invention relates to a lithium cobalt oxide-carbon composite for a lithium ion capacitor, a positive electrode active material including the same, a lithium ion capacitor including the same, and a manufacturing method thereof.

With the spread of mobile electronic devices such as smartphones, the development of secondary batteries such as nickel hydride batteries, lithium secondary batteries, super capacitors, and lithium ion capacitors is actively progressing. The lithium ion capacitor (LIC) is a new concept that has both the high power and long life advantages of the existing electric double layer capacitor (EDLC) and the high energy density of the lithium ion battery. It is in the spotlight as a secondary battery system.

The electric double layer capacitor is limited in various applications due to its low energy density despite its excellent output characteristics and lifetime characteristics. As a means of solving the problem of the electric double layer capacitor, a hybrid capacitor having improved energy density has been proposed by applying a material capable of inserting and desorbing lithium ions into a positive electrode active material or a negative electrode active material. In particular, a lithium ion capacitor has been proposed that uses a positive electrode active material applied to an existing electric double layer capacitor as a positive electrode and a carbon-based material capable of intercalating and desorbing lithium ions as a negative electrode active material in the negative electrode.

Since the lithium ion capacitor uses a material capable of intercalating and desorbing lithium ions at a low reaction potential as a negative electrode active material, the degree of improvement in energy density is greater than that of other hybrid capacitors. In particular, lithium ion capacitors can significantly lower the potential of the negative electrode by pre-doping lithium ions having a high ionization tendency on the negative electrode, and the cell voltage can also be improved compared to the conventional electric double layer capacitor, enabling high voltage implementation and high energy density. Can be implemented.

However, such a lithium ion capacitor requires a lithium doping process for not only electrochemical adsorption and desorption reactions but also lithium insertion and desorption reactions. In the conventional lithium doping process technology, there is a method in which the laminated metallic lithium melts into the negative electrode due to the potential difference between the negative electrode and the metallic lithium simply by laminating metallic lithium on an electrode and then shorting the negative electrode and metallic lithium by putting an electrolyte solution. However, this method has a problem that it is difficult to control the amount of lithium doped into the negative electrode, it is difficult to secure safety according to the lithium metal generated in the doping process, and thus it is difficult to apply it to mass production.

Korean Patent Publication No. 2012-0035131

An object of the present invention is to provide a lithium cobalt oxide-carbon composite for a lithium ion capacitor capable of stably doping lithium electrochemically in a negative electrode, a positive electrode active material including the same, a lithium ion capacitor including the same, and a manufacturing method thereof. . In addition, it is possible to provide a lithium cobalt oxide-carbon composite for a lithium ion capacitor capable of stably processing even in a moisture environment.

In addition, doping efficiency and safety can be improved, and a manufacturing method suitable for mass production can be provided.

In addition, it is possible to provide a lithium ion capacitor having high energy density, excellent output characteristics, and life characteristics.

The lithium cobalt oxide-carbon composite for a lithium ion capacitor according to an embodiment of the present invention includes a lithium metal compound and carbon, and is represented by the following formula.

[Chemical Formula]

Li _6-x CoO ₄ ·C

In the above formula, 0≤x≤4.

The content of carbon may be 5wt% or less with respect to the total composition.

The carbon may be derived from sucrose.

The cathode active material for a lithium ion capacitor according to an embodiment of the present invention includes a lithium metal compound and carbon, and includes a lithium cobalt oxide-carbon composite represented by the following formula.

[Chemical Formula]

Li _6-x CoO ₄ ·C

In the above formula, 0≤x≤4.

A lithium ion capacitor according to an embodiment of the present invention includes a lithium metal compound and carbon, and includes a cathode active material for a lithium ion capacitor represented by the following formula.

[Chemical Formula]

Li _6-x CoO ₄ ·C

In the above formula, 0≤x≤4.

A method of preparing a cathode active material additive for a lithium ion capacitor according to an embodiment of the present invention comprises the steps of forming a mixture by mixing containing a lithium precursor, cobalt oxide, and a reducing agent; Heat-treating the mixture; And obtaining a lithium cobalt oxide-carbon composite for a lithium ion capacitor from the heat-treated mixture.

The lithium precursor may be lithium hydroxide.

The reducing agent may be sucrose.

In the step of forming the mixture, the content of the lithium precursor may be 65 to 78 wt% with respect to the total mixture, and the content of the cobalt oxide may be 17 to 30 wt% with respect to the total mixture.

In the step of forming the mixture, the content of the reducing agent may be 4 to 6 wt% based on the total mixture.

The heat treatment may be performed for 5 to 20 hours at a temperature of 750 to 950°C.

The lithium cobalt oxide-carbon composite for a lithium ion capacitor according to an embodiment of the present invention can stably dop lithium electrochemically in a negative electrode. In addition, it is possible to provide a lithium cobalt oxide-carbon composite for a lithium ion capacitor capable of stably processing even in a moisture environment.

In addition, doping efficiency and safety can be improved, and a manufacturing method suitable for mass production can be provided.

In addition, it is possible to provide a lithium ion capacitor having high energy density, excellent output characteristics, and life characteristics.

1 shows a lithium ion capacitor according to an embodiment of the present invention.
Figure 2 shows a method of manufacturing a lithium cobalt oxide-carbon composite for a lithium ion capacitor according to an embodiment of the present invention.
3 is an EDS analysis result of an example.
4 shows the XRD analysis results of Examples, and FIGS. 5 to 11 show the XRD analysis results of Comparative Examples 1 to 7.
12 is an electrical characteristic analysis graph of an embodiment, and FIGS. 13 and 14 are electrical characteristic analysis graphs of Comparative Examples 6 and 7, respectively.
15 is an XRD graph for evaluating water stability in Examples.
16 is an XRD graph for evaluating water stability in Comparative Example 1.
17 is a graph showing voltage changes according to capacity during pre-doping.
18 is a graph showing voltage changes according to capacity of a lithium ion capacitor during charging and discharging.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. However, embodiments of the present invention may be modified in various other forms, and the scope of the present invention is not limited to the embodiments described below. In addition, embodiments of the present invention are provided in order to more completely explain the present invention to those having average knowledge in the art.

Lithium cobalt oxide-carbon composite for lithium ion capacitors

The lithium cobalt oxide-carbon composite for a lithium ion capacitor according to an embodiment of the present invention includes a lithium metal compound and carbon, and is represented by the following formula.

[Chemical Formula]

Li _6-x CoO ₄ ·C

In the above formula, 0≤x≤4.

The lithium metal compound may exist in a crystalline or amorphous phase, and carbon may be distributed and disposed in an atom, a crystalline phase, or an amorphous phase in the crystal grains of the lithium metal compound or in the amorphous phase or in the grain boundaries. The formula of the lithium metal compound is represented by Li _6-x CoO ₄ and 0≦ _x ≦ ₄ in the above formula.

The content of carbon in the total lithium cobalt oxide-carbon composite may be 10 wt% or less, preferably 5 wt% or less. Since carbon is derived from a reducing agent during the manufacturing process of the lithium cobalt oxide-carbon composite, the content in the final product lithium cobalt oxide-carbon composite can be determined by controlling the total amount of the added reducing agent. Specifically, the carbon may be derived from sucrose.

The lithium cobalt oxide-carbon composite for a lithium ion capacitor may have an average particle diameter of 10 μm or less. When having such an average particle diameter range, the lithium ion capacitor using this may have high capacity and high efficiency characteristics.

Positive active material for lithium ion capacitors

The cathode active material for a lithium ion capacitor according to an embodiment of the present invention includes a lithium metal compound and carbon, and includes a lithium cobalt oxide-carbon composite represented by the following formula.

[Chemical Formula]

Li _6-x CoO ₄ ·C

In the above formula, 0≤x≤4.

In addition, a binder and a conductive material may be further included, and the lithium cobalt oxide-carbon composite for a lithium ion capacitor, a binder, and a conductive material may be mixed in a solvent in a liquid or gel form.

The lithium cobalt oxide-carbon composite was described above.

The content of each component in the positive electrode active material for a lithium ion capacitor may be 20 to 50 wt% of a lithium cobalt oxide-carbon composite, 1 to 60 wt% of a binder, and 1 to 10 wt% of a conductive agent, based on the entire positive electrode active material. It may further contain 1 to 20wt%.

The binder is not particularly limited as long as it is generally used in the art, and examples include polyvinylidene fluoride, polyvinyl alcohol, carboxymethylcellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, Polyvinylpyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene butyrene rubber and fluorine rubber.

The conductive agent is not particularly limited as long as it is a conductive material generally used in the art, and examples thereof include graphite; It may include any one of carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, thermal black, metal powder, and metal oxide.

The solvent may be an organic solvent or water.

Lithium ion capacitor

1 shows a lithium ion capacitor 100 according to an embodiment of the present invention.

The lithium ion capacitor 100 according to the embodiment of the present invention includes a lithium metal compound and carbon, and includes a positive electrode active material for a lithium ion capacitor represented by the following formula.

[Chemical Formula]

Li _6-x CoO ₄ ·C

In the above formula, 0≤x≤4.

Referring to FIG. 1, a lithium ion capacitor 100 includes a positive electrode current collector 120, a positive electrode active material 110 disposed on the positive electrode current collector 120, a negative electrode current collector 140, and the negative electrode current collector 140. ) The anode active material 130 disposed on, the separator 150 disposed between the cathode active material 110 and the anode active material 130, and the movement path of lithium ions in the cathode active material 110 and the anode active material 130 It may be configured to include an electrolyte solution 160 to provide a.

The positive active material for a lithium ion capacitor is described above.

The positive electrode current collector and the negative electrode current collector function as a support for supporting the positive electrode active material and the negative electrode active material, respectively, and may be connected to an external electrode to provide a current passage. The positive electrode current collector and the negative electrode current collector may be in the form of a film, a porous material, a foam, and a mesh, and may be made of a conductive material such as stainless steel or aluminum.

The negative active material may be a carbon-based material capable of intercalating and desorbing lithium ions, and is not particularly limited.

The electrolytic solution serves as a medium capable of moving lithium ions, and includes an electrolyte and a solvent. The electrolyte may include any one lithium salt of LiPF ₆ , LiBF ₄ and LiCIO ₄ , and is not particularly limited.

The separator may include pores through which lithium ions can pass, and may be made of a polymer material such as a polypropylene film.

Method for producing lithium cobalt oxide-carbon composite for lithium ion capacitors

Figure 2 shows a method of manufacturing a lithium cobalt oxide-carbon composite for a lithium ion capacitor according to an embodiment of the present invention.

A method of manufacturing a lithium cobalt oxide-carbon composite for a lithium ion capacitor according to an embodiment of the present invention comprises: forming a mixture by mixing a lithium precursor, cobalt oxide, and a reducing agent; Heat-treating the mixture; And obtaining a lithium cobalt oxide-carbon composite for a lithium ion capacitor from the heat-treated mixture.

In the step of forming the mixture, a lithium precursor, cobalt oxide, and a reducing agent may be mixed using a stirrer or a mixer.

The cobalt oxide may be mixed in a powder state, and in this case, the average particle diameter of the cobalt oxide powder may be 10 to 100 μm. The cobalt oxide may have a formula of CoO or Co ₃ O ₄ .

The lithium precursor may be lithium hydroxide, lithium carbonate, lithium fluoride, and a mixture thereof, and preferably lithium hydroxide. The lithium precursor may be mixed in a powder state, and in this case, the average particle diameter of the lithium precursor may be 10 to 50 μm.

The reducing agent may be a material containing carbon, preferably sucrose. Li _6-x CoO ₄ ·C can be stably produced by using sucrose as the reducing agent.

In this step, in the step of forming the mixture, the content of the lithium precursor may be 65 to 78 wt%, preferably 70 to 75 wt%, based on the total mixture. The content of the cobalt oxide may be 17 to 30 wt%, preferably 20 to 25 wt%, based on the total mixture. In the step of forming the mixture, the content of the reducing agent may be 4 to 6 wt% based on the total mixture. By controlling the content of each component as described above, it is possible to minimize the formation of unreacted substances or impurities in the finally generated lithium cobalt oxide-carbon composite, thereby maximizing the efficiency of the prepared positive electrode active material.

The heat treatment may be performed for 5 to 20 hours at a temperature of 750 to 950°C. If the heat treatment temperature is less than 750℃, there is a problem that the unreacted lithium precursor and cobalt oxide remain because the lithium precursor, cobalt oxide and reducing agent do not react sufficiently, and if it exceeds 950℃, the prepared lithium cobalt oxide- A problem of lowering the sphericity and density of the carbon composite may occur, and a problem of remaining cobalt oxide may occur.

Next, a lithium cobalt oxide-carbon composite for a lithium ion capacitor is obtained from the heat-treated mixture. In this step, if necessary, it may further include washing and drying the heat-treated mixture with water.

Method of manufacturing positive electrode for lithium ion capacitor

The positive electrode includes a positive electrode current collector and a positive electrode active material disposed on the positive electrode current collector. A method of manufacturing a positive electrode according to an exemplary embodiment of the present invention includes forming a mixture by mixing a lithium cobalt oxide-carbon composite for a lithium ion capacitor prepared by the method described above, a conductive agent, a binder, and a solvent; Applying the mixture to a positive electrode current collector; And drying the mixture applied to the positive electrode current collector.

In the step of forming a mixture by mixing the lithium cobalt oxide-carbon composite for the lithium ion capacitor, a conductive agent, a binder, and a solvent, the content of each component is 1 to 60 wt% of the binder and 1 to 10 wt% of the conductive agent based on the total mixture , 1 to 20wt% of the solvent and the balance lithium cobalt oxide-carbon composite. In addition, the content of the lithium cobalt oxide-carbon composite may be 20 to 50 wt% based on the total mixture.

The binder is not particularly limited as long as it is generally used in the art, and examples include polyvinylidene fluoride, polyvinyl alcohol, carboxymethylcellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, Polyvinylpyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene butyrene rubber and fluorine rubber.

The conductive agent is not particularly limited as long as it is a conductive material generally used in the art, and examples thereof include graphite; It may include any one of carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, thermal black, metal powder, and metal oxide.

The solvent may be an organic solvent or water.

In the step of applying the mixture to the positive electrode current collector, the positive electrode current collector functions as a support for supporting the positive electrode active material, and may be connected to an external electrode to provide a current passage. The positive electrode current collector may be in the form of a film, a porous material, a foam, and a mesh, and may be made of a conductive material such as stainless steel or aluminum.

Examples and Comparative Examples

Example

As a lithium precursor, 0.7583 g of lithium hydroxide (LiOH.H ₂ O) from L&F, 0.2417 g of cobalt oxide (Co ₃ O ₄ ) from L&F, and 0.0556 g of Sigma Aldrich's sucrose as a reducing agent were mixed, and gun mixing was performed. Run for 30 minutes. The content of sucrose in the whole mixture was 5.3 wt%.

Next, the mixture was heat-treated in an Ar atmosphere. The heat treatment was carried out by heating up to 800° C. at a heating rate of 5° C./min, and then maintaining at 800° C. for 10 hours.

Next, the heated mixture was gradually cooled to room temperature to obtain a lithium cobalt oxide-carbon composite for a lithium ion capacitor.

Comparative Example 1

It was prepared in the same manner as in Examples, except that only lithium hydroxide and cobalt oxide were mixed without including a reducing agent.

Comparative Example 2

It was prepared in the same manner as in Examples, except that 0.0556 g of stearic acid was mixed instead of sucrose as a reducing agent.

Comparative Example 3

It was prepared in the same manner as in Examples, except that 0.0556g of Super P was mixed instead of sucrose as a reducing agent.

Comparative Example 4

Except that the heat treatment temperature was set to 700°C, it was prepared in the same manner as in Example.

Comparative Example 5

Except that the heat treatment temperature was set to 900°C, it was prepared in the same manner as in Examples.

Comparative Example 6

It was prepared in the same manner as in Examples, except that the amount of sucrose was mixed at 0.0252 g. The content of sucrose in the total mixture was 2.4 wt%.

Comparative Example 7

It was prepared in the same manner as in Examples, except that the amount of sucrose was mixed at 0.0923 g. The content of sucrose in the whole mixture was 8.8 wt%.

Experiment example

EDS analysis

3 is an EDS analysis result of an example. According to the EDS analysis, the contents of C, O, and Co included in the examples are shown in Table 1.

element Wt% C 3.24 O 58.11 Co 38.66 total 100.00

XRD analysis

For Examples and Comparative Examples 1 to 7, XRD analysis was performed using Cu-Kα1 radiation. 4 shows the XRD analysis results of Examples, and FIGS. 5 to 11 show the XRD analysis results of Comparative Examples 1 to 7.

Referring to FIGS. 4 to 7, it can be seen that when sucrose is added as a reducing agent, the final product is generated in a stable form compared to when a reducing agent is not added or another carbon source is added. When a reducing agent is not added or other types of carbon sources are added, materials such as α-Co and β-Co are generated, and when these are used as a positive electrode active material, pre-doping of the negative electrode may not be efficiently performed.

4, 8, and 9, it can be seen that when the heat treatment temperature is 800° C., the final product is generated in a stable form. When the heat treatment temperature is 700° C. and 900° C., a material such as CoO is generated, and when it is used as a positive electrode active material, pre-doping of the negative electrode may not be efficiently performed.

4, 10 and 11, it can be seen that when the content of the reducing agent is 5.3 wt%, the final product is generated in a stable form. When the content of the reducing agent is 2.4 wt% and 8.8 wt%, materials such as α-Co, β-Co, and CoO are generated, and when these are used as a positive electrode active material, pre-doping of the negative electrode may not be performed efficiently.

Electrical characteristic analysis

To analyze the electrical characteristics, a coin cell was manufactured and a coin cell test was conducted. The positive electrode was prepared by mixing the composites obtained in Examples and Comparative Examples, Super P and PVdF at a weight ratio of 90:5:5, respectively, and lithium metal was used as the negative electrode. As the electrolyte, 1.3M LiPF ₆ in EC:DMC=3:7 (v/v) was used. Charging and discharging conditions were CC, cut-off 2.0 to 4.3V was applied, and the cycle was performed three times with 0.1C charging/discharging.

12 is an electrical characteristic analysis graph of an embodiment, and FIGS. 13 and 14 are electrical characteristic analysis graphs of Comparative Examples 6 and 7, respectively. Table 2 shows the results of electrical characteristic analysis of Examples and Comparative Examples 6 and 7.

Number of cycles Example Comparative Example 6 Comparative Example 7 Charging capacity
(mAh/g) Discharge capacity
(mAh/g) Charging capacity
(mAh/g) Discharge capacity
(mAh/g) Charging capacity
(mAh/g) Discharge capacity
(mAh/g) 1 time 606.37 7.58 390.27 9.35 412.29 11.58 Episode 2 6.22 4.71 22.30 7.05 14.49 8.44 3rd time 3.38 3.78 14.68 5.76 9.37 5.92

Referring to Table 2 and FIGS. 12 to 14, it can be seen that the charging and discharging characteristics are improved in the case of the embodiment.

Moisture stability evaluation

Example and Comparative Example 1 were left at a temperature of 30° C. and a relative humidity of 25% for 30 minutes, and then XRD was measured using Cu-Kα1 radiation. 15 is an XRD graph for evaluating water stability in Example, and FIG. 16 is an XRD graph for evaluating water stability in Comparative Example 1.

In the case of the embodiment, comparing Figs. 4 and 15, it can be seen that there is no change in the peak on the XRD graph. On the other hand, in the case of Comparative Example 1, when comparing FIGS. 5 and 16, it can be seen that the peak height on the XRD graph is changed. Through this, it can be seen that the embodiment has higher moisture stability than the comparative example.

Analysis of electrical properties of lithium ion capacitors

To analyze the electrical characteristics of the lithium ion capacitor, a beaker cell test was performed. The positive electrode was prepared by mixing the composite obtained in Examples and Comparative Examples, activated carbon (AC, Activated carbon), Super P, and PVdF in a weight ratio of 18:72:5:5, respectively, and the negative electrode was natural graphite. ), CMC and SBR were prepared by mixing in a ratio of 96:2:2 by weight, respectively. As the electrolyte, 1.3M LiPF ₆ in EC:DMC=3:7 (v/v) was used.

17 is a graph showing voltage changes according to capacity during pre-doping. Pre-doping was performed by charging up to 4.2V under the condition of 0.1C.

18 is a graph showing voltage changes according to capacity of a lithium ion capacitor during charging and discharging. The charge/discharge conditions were cut-off 1.5-3.9V, and 0.1C charge/discharge cycles were performed twice.

The present invention is not limited by the above-described embodiments and the accompanying drawings, but is intended to be limited by the appended claims. Therefore, various types of substitutions, modifications and changes will be possible by those of ordinary skill in the art within the scope not departing from the technical spirit of the present invention described in the claims, and this also belongs to the scope of the present invention. something to do.

100: lithium ion capacitor
110: positive active material
120: positive electrode current collector
130: negative active material
140: negative electrode current collector
150: separator
160: electrolyte

Claims (13)

Including lithium metal compounds and carbon,
Represented by the following formula,
Lithium cobalt oxide-carbon composite for lithium ion capacitors:
[Chemical Formula] Li _6-x CoO ₄ ·C
In the above formula, 0≤x≤4, and the content of carbon is 5 wt% or less with respect to the entire composite.
delete The method of claim 1,
The carbon is derived from sucrose (sucrose),
Lithium cobalt oxide-carbon composite for lithium ion capacitors.
Including a lithium metal compound and carbon, including a lithium cobalt oxide-carbon composite represented by the following formula,
Positive active material for lithium ion capacitors:
[Chemical Formula] Li _6-x CoO ₄ ·C
In the above formula, 0≤x≤4, and the content of carbon is 5 wt% or less with respect to the entire composite.
Including a lithium metal compound and carbon, and a lithium cobalt oxide represented by the following formula-including a positive electrode active material for a lithium ion capacitor containing a carbon composite,
Li-ion capacitor.
[Chemical Formula] Li _6-x CoO ₄ ·C
In the above formula, 0≤x≤4, and the content of carbon is 5 wt% or less with respect to the entire composite.
Comprising a lithium precursor, cobalt oxide, and a reducing agent, and mixing to form a mixture;
Heat-treating the mixture; And
Including; obtaining a lithium cobalt oxide-carbon composite for a lithium ion capacitor represented by the following formula from the heat-treated mixture;
A method for producing a lithium cobalt oxide-carbon composite for a lithium ion capacitor according to claim 1.
[Chemical Formula] Li _6-x CoO ₄ ·C
In the above formula, 0≤x≤4, and the content of carbon is 5 wt% or less with respect to the entire composite.
The method of claim 6,
The lithium precursor is lithium hydroxide,
Method for producing a lithium cobalt oxide-carbon composite for a lithium ion capacitor.
The method of claim 6,
The reducing agent is sucrose (sucrose),
Method for producing a lithium cobalt oxide-carbon composite for a lithium ion capacitor.
The method of claim 6,
In the step of forming the mixture,
The content of the lithium precursor is 65 to 78 wt% based on the total mixture
Method for producing a lithium cobalt oxide-carbon composite for a lithium ion capacitor.
The method of claim 6,
In the step of forming the mixture,
The content of cobalt oxide is 17 to 30 wt% based on the total mixture
Method for producing a lithium cobalt oxide-carbon composite for a lithium ion capacitor.
The method of claim 6,
In the step of forming the mixture,
The content of the reducing agent is 4 to 6 wt% based on the total mixture,
Method for producing a lithium cobalt oxide-carbon composite for a lithium ion capacitor.
The method of claim 6,
The heat treatment step,
Carried out at a temperature of 750 to 950 °C,
Method for producing a lithium cobalt oxide-carbon composite for a lithium ion capacitor.
The method of claim 6,
The heat treatment step,
Carried out for 5 to 20 hours,
Method for producing a lithium cobalt oxide-carbon composite for a lithium ion capacitor.

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