Electrode Composition for Energy Storage Device, Method for Manufacturing the Same, and Energy Storage Device Including an Electrode Manufactured Using the Same

Abstract

The present invention relates to an electrode composition for an energy storage device, a method for manufacturing the same, and an energy storage device comprising an electrode including an electrode manufactured using the same. One embodiment can provide an eco-friendly and high-performance electrode composition by recycling municipal waste and can be utilized as an electrode for a supercapacitor. An electrode composition for an energy storage device according to an embodiment of the present invention comprises an active material comprising a carbon material prepared by carbonizing black tea; a conductive material and a binder. The active material may further comprise manganese oxide (MnOx, where x is a natural number) disposed on the surface of the carbon material.

Description

Technology Field

[0001] The present invention relates to an electrode composition for an energy storage device, a method for manufacturing the same, and an energy storage device comprising an electrode including an electrode manufactured using the same. One embodiment can provide an eco-friendly and high-performance electrode composition by recycling municipal waste and can be utilized as an electrode for a supercapacitor. Background Technology

[0002] Energy storage devices compensate for the instability of power supply and are used in various fields associated with intermittent power sources such as renewable energy. In particular, supercapacitors are widely utilized in new and renewable energy systems, electric vehicles, and portable electronic devices due to their high power density, fast charging and discharging speeds, and long lifespan.

[0003] In general, the performance of supercapacitors depends heavily on the electrode materials. Activated carbon, currently the primary electrode material, provides a high specific surface area, but the use of toxic chemicals in its manufacturing process causes environmental problems. Accordingly, there is a need to develop new electrode materials that are environmentally friendly while maintaining high performance. Prior art literature

[0004] Korean Registered Patent Publication No. 10-1409178 The problem to be solved

[0005] The present invention aims to provide an environmentally friendly electrode composition for an energy storage device, a method for manufacturing the same, and an energy storage device comprising an electrode including an electrode manufactured using the same.

[0006] In addition, the present invention can provide an electrode composition for an energy storage device having high energy density and improved electrochemical properties. means of solving the problem

[0007] An electrode composition for an energy storage device according to an embodiment of the present invention comprises an active material comprising a carbon material prepared by carbonizing black tea; a conductive material and a binder. The active material comprises manganese oxide (MnO₂) disposed on the surface of the carbon material. x , where x is a natural number) may also be included.

[0008] The above carbon material may be manufactured by performing the process at 700 to 900 ℃ in a non-flammable atmosphere.

[0009] The content of each composition may be 70 to 90 weight% of the carbon material, 5 to 15 weight% of the conductive agent, and 5 to 15 weight% of the binder, based on the total weight.

[0011] An energy storage device according to an embodiment of the present invention includes an electrode made of an electrode composition.

[0013] A method for manufacturing an electrode composition for an energy storage device according to an embodiment of the present invention comprises the steps of carbonizing black tea to produce an active material containing a carbon material, and adding a conductive material and a binder to the active material and mixing them.

[0014] The step of manufacturing the above active material may further include the step of coating manganese oxide on the surface of the carbon material.

[0015] The step of coating the manganese oxide may include mixing manganese (II) acetate tetrahydrate with potassium permanganate (KMnO4). Effects of the invention

[0016] The electrode composition for an energy storage device and the method for manufacturing the same according to the embodiments of the present invention are environmentally friendly.

[0017] In addition, the present invention can provide an electrode composition for an energy storage device having high energy density and improved electrochemical properties. Brief explanation of the drawing

[0018] Figure 1 is the result of the EDS analysis. Figure 2 is the SEM analysis result. Figure 3 shows the XRD analysis results. Figures 4 to 6 show the results of the cyclic current analysis. Figures 7 to 9 show the results of the specific capacitance analysis. Figures 10 to 12 show the results of the energy density-power density graph analysis. Specific details for implementing the invention

[0019] Hereinafter, preferred embodiments of the present invention are described as follows with reference to the attached 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. Furthermore, embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art.

[0021] An electrode composition for an energy storage device according to an embodiment of the present invention comprises an active material comprising a carbon material prepared by carbonizing black tea; a conductive material and a binder.

[0023] The above active material serves to store and release energy. In the present invention, the above active material includes a carbon material prepared by carbonizing black tea. In one embodiment, the above active material is manganese oxide (MnO₂) disposed on the surface of the carbon material. x , where x is a natural number) may also be included.

[0024] The above carbon material may be amorphous carbon. This is because the carbonization temperature of black tea is relatively low, at the level of 700 to 800 ℃, and graphitization does not proceed because a crystal structure is not well formed due to impurities contained in the black tea residue. The above carbon material is amorphous carbon, and because it has porosity and a large specific surface area, it has excellent electrical properties.

[0025] One embodiment may further include manganese oxide to improve the performance of the electrode. The manganese oxide may be coated on part or all of the surface of the carbon material. The manganese oxide provides pseudocapacitance characteristics that store charge through oxidation-reduction reactions. Pseudocapacitance is one of the energy storage mechanisms occurring in supercapacitors, which stores charge through oxidation-reduction reactions at the surface or interface between the electrode and the electrolyte, and has a high energy storage density. As such, by further including manganese oxide, the present invention can improve energy density, increase specific capacitance, and improve charge-discharge characteristics. In the present invention, the content of manganese oxide may be 28 to 46 weight% with respect to the total weight of the electrode composition for an energy storage device, and the coated thickness may be 0.01 to 0.03 mm.

[0027] The above conductive material is used to enhance electrical conductivity in electrodes of energy storage devices, such as supercapacitors. The conductive material facilitates electron movement between active materials within the electrode and lowers internal resistance, thereby optimizing the electrochemical performance of the electrode.

[0028] The above conductive material may be carbon black, carbon nanotubes (CNT), graphene, etc.

[0029] In the present invention, the content of the conductive material may be 5 to 15 weight percent based on the total weight of the electrode composition for an energy storage device. If the amount of conductive material is too high, the proportion of the active material decreases, which may reduce the total capacity of the electrode, and if the amount is too low, the electrode resistance increases, which may degrade performance.

[0031] The above binder combines the active material and the conductive material to maintain the electrode uniformly and ensures that the electrode maintains a physically and chemically stable structure.

[0032] The above binder may be polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), carboxymethylcellulose (CMC), polyacrylonitrile (PAN), SBR (Styrene-Butadiene Rubber), etc.

[0033] In the present invention, the content of the binder may be 5 to 15 weight percent based on the total weight of the electrode composition for an energy storage device. If the binder is too abundant, conductivity may decrease and performance may be reduced, whereas if it is too scarce, the active material and the conductive material may not be sufficiently bonded, causing the electrode to separate.

[0035] The above carbon material may be manufactured by performing the process at 700 to 900 ℃ in a non-flammable atmosphere.

[0036] The content of each composition may be 70 to 90 weight% of the carbon material, 5 to 15 weight% of the conductive agent, and 5 to 15 weight% of the binder, based on the total weight.

[0038] An energy storage device according to an embodiment of the present invention includes an electrode made of an electrode composition. The energy storage device, which includes the active material, binder, and conductive material described above, can be manufactured by mixing the electrode composition in a solvent, molding, and drying. Such an electrode manufacturing process may be carried out by general methods used in the field and is not particularly limited.

[0040] A method for manufacturing an electrode composition for an energy storage device according to an embodiment of the present invention comprises the steps of carbonizing black tea to produce an active material containing a carbon material, and adding a conductive material and a binder to the active material and mixing them.

[0042] The step of manufacturing the active material may include the step of manufacturing the carbon material and the step of coating the surface of the carbon material with manganese oxide.

[0043] The step of manufacturing the carbon material above can be performed by heating black tea or black tea residue, etc. to a high temperature to carbonize it. One embodiment may include the steps of collecting black tea or black tea residue, washing, drying, and grinding; placing the black tea or black tea residue into a tube furnace or electric furnace, etc., and heating it in an inert atmosphere to carbonize it; and grinding the carbonized material and performing subsequent processes such as washing or removing impurities.

[0044] The carbonization step described above can be performed at 700 to 900 ℃, preferably 800 ℃. Through this, the carbon material becomes amorphous and porous, thereby increasing the specific surface area and improving electrical properties.

[0045] The step of coating the manganese oxide is a step of placing it on the surface of the carbon material. In one embodiment, the content of manganese oxide may be 28 to 46 weight% with respect to the total weight of the electrode composition for an energy storage device, and the coated thickness may be 0.01 to 0.03 mm. This step may include a step of mixing manganese(II) acetate tetrahydrate and potassium permanganate (KMnO4). More specifically, this step may include a step of preparing a mixed solution by mixing the carbon material, manganese(II) acetate tetrahydrate, and a solvent, a step of adding the potassium permanganate solution to the mixed solution, and a step of vacuum filtering and drying the solution.

[0046] The step of preparing the above mixed solution can be performed by first mixing manganese (II) acetate tetrahydrate and a solvent to prepare a manganese (II) acetate tetrahydrate solution, and then adding a carbon material thereto. Here, the weight ratio of the carbon material to the manganese (II) acetate tetrahydrate may be 1.5:1 to 2:1. The solvent may be deionized water.

[0047] In the step of adding the potassium permanganate solution to the above mixed solution, the concentration of the potassium permanganate solution may be 0.1 to 0.15 M. In this step, an amount of potassium permanganate solution equal to that of the above mixed solution may be added.

[0048] Next, the solution mixed with potassium permanganate solution may be vacuum filtered and dried. The vacuum filtration may be performed using methods generally practiced in the field. The drying process may be performed at 100°C or higher to sufficiently remove the solvent.

[0050] Preparation Example: Preparation of active material

[0051] Preparation Example 1 (Black tea grounds): Twinings English Breakfast black tea grounds were used. The black tea grounds were placed in a tube furnace, an N2 atmosphere was formed, and the temperature was increased from room temperature to 800 ℃ at a heating rate of 5 ℃ / min, and heated at 800 ℃ for 2 hours. The black tea grounds after carbonization were crushed to obtain a carbon material.

[0053] Preparation Example 2 (Coffee): A carbon material was prepared in the same manner as Preparation Example 1, except that coffee grounds sourced from a coffee specialty store were used instead of black tea grounds.

[0055] Preparation Example 3 (Mask Filter): A carbon material was prepared in the same manner as Preparation Example 1, except that a mask filter obtained from a KF 94 mask was used instead of black tea grounds.

[0057] Preparation Example 4 (Tissue): A carbon material was prepared in the same manner as Preparation Example 1, except that Kimtech was used instead of black tea grounds.

[0059] Preparation Example 5 (Black tea residue + manganese oxide): 5 g of the carbon material prepared in Preparation Example 1, 2.87 g of manganese(II) acetate tetrahydrate, and 50 mL of distilled water were placed in a stirrer and stirred at 300 rpm for 3 hours. 50 mL of a 0.13 M potassium permanganate (KMnO4) solution was added and mixed. The mixture was filtered using a vacuum filter, and the residue was placed in an oven and dried at 105 ℃. Through this process, a carbon material coated with manganese oxide was prepared.

[0061] Preparation Example 6 (Coffee + Manganese Oxide): A carbon material coated with manganese oxide was prepared using the same method as in Preparation Example 5, except that the carbon material prepared in Preparation Example 2 was used.

[0064] Example: Energy Manufacturing of electrodes for storage devices

[0065] Example 1 (black tea residue): 0.4 g of the carbon material from Preparation Example 1, 0.1 g of PTFE as a binder, and 0.1 g of carbon black as a conductive material were mixed in ethyl alcohol as a solvent to make a slurry. This slurry was compressed and coated onto a 1 x 5 cm stainless steel plate to a thickness of 0.01 to 0.03 mm using a compressor, and heated in an oven to manufacture an electrode for an energy storage device.

[0067] Example 2 (Coffee): Prepared in the same manner as Example 1, except that the carbon material of Preparation Example 2 was used.

[0069] Example 3 (Mask Filter): Manufactured in the same manner as Example 1, except that the carbon material of Manufacturing Example 3 was used.

[0071] Example 4 (Tissue): Prepared in the same manner as Example 1, except that the carbon material of Preparation Example 4 was used.

[0073] Example 5 (black tea residue + manganese oxide): Prepared in the same manner as Example 1, except that the carbon material of Preparation Example 5 was used.

[0075] Example 6 (Coffee + Manganese Oxide): Prepared in the same manner as Example 1, except that the carbon material of Preparation Example 6 was used.

[0077] Comparative Example (Graphite): Prepared in the same manner as Example 1, except that carbon black was used.

[0079] Experimental Example: EDS Analysis

[0080] EDS analysis was performed on Examples 5 and 6, and the results are shown in Figures 1(a) and (b), respectively.

[0081] Referring to Figure 1, it can be seen that manganese oxide is coated as manganese and oxygen atoms are applied to the carbon surface.

[0083] Experimental Example: SEM Analysis

[0084] For Examples 1 to 4 and Comparative Examples, SEM analysis was performed using FESEM (Field Emission Scanning Electron Microscopy, Apreo S HiVac, FEI Company) at an operating voltage of 15 kV, and the results are shown in Figure 2.

[0085] Referring to Figure 2, it is confirmed that Example 1 has the best porosity and a large surface area.

[0087] Experimental Example: XRD Analysis

[0088] XRD analysis was performed on Examples 1 to 4 and graphite. XRD analysis was performed using an X-ray diffractometer (XRD, D8 ADVANCE, Bruker), and measurements were taken at 2θ angles from 20° to 80° under conditions of an acceleration voltage of 40 kV and a current of 30 mA, and the results are shown in Fig. 3.

[0089] Referring to FIG. 3, Examples 1 to 4 did not show distinct crystalline peaks, and in particular, Example 1 showed almost no crystalline peaks. This indicates that Example 1 has an amorphous structure.

[0091] For the analysis of cyclic voltammetry, specific capacitances, and energy density-power density graphs (Ragone Plot), a three-electrode system was constructed using the example as the working electrode, the Ag / AgCl (saturated 1M KCl) electrode as the reference electrode, and the Pt electrode as the counter electrode.

[0093] Experimental Example: Cyclic Voltammetry Analysis

[0094] Figure 4 shows the results of the cyclic current analysis of Examples 1 to 4. Referring to Figure 4, it can be seen that Example 1 has the highest capacitance. This indicates that the oxidation and reduction reactions are active in Example 1.

[0095] Figure 5 shows the results of the cyclic current analysis of Examples 1 and 5, and Figure 6 shows the results of the cyclic current analysis of Examples 2 and 6. Referring to Figures 5 and 6, it can be seen that the capacitance is improved by coating with manganese oxide, thereby improving the performance as an electrode.

[0097] Experimental Example: Analysis of Specific Capacitances

[0098] Figure 7 shows the results of the specific capacitance analysis of Examples 1 to 4. Referring to Figure 7, it can be seen that Example 1 exhibits the highest specific capacitance at scan rates of 5 mV / s and 10 mV / s, and that it exhibits the same specific capacitance even when the scan rate is changed from 100 mV / s back to 10 mV / s. In other words, since Example 1 exhibits high specific capacitance even at low scan rates, it can be seen that it has the best characteristics as an electrode.

[0099] Figure 8 shows the specific capacitance analysis results of Examples 1 and 5, and Figure 9 shows the specific capacitance analysis results of Examples 2 and 6. Referring to Figures 8 and 9, it can be seen that the performance as an electrode is improved by coating with manganese oxide, which exhibits high specific capacitance even at low scan speeds.

[0101] Experimental Example: Energy Density-Power Density Graph (Ragone Plot) Analysis

[0102] Figure 10 shows the results of the energy density-power density graph (Ragone Plot) analysis of Examples 1 to 4. Referring to Figure 10, it can be seen that Example 1 maintains high energy density and power density simultaneously. This means that the power density does not decrease significantly even when the energy density increases, making it very stable as an electrode material.

[0103] Figure 11 shows the results of the energy density-power density graph analysis for Examples 1 and 5, and Figure 12 shows the results for Examples 2 and 6. Referring to Figures 11 and 12, it can be seen that by coating with manganese oxide, higher energy density and higher power density are maintained simultaneously, thereby improving performance as an electrode.

[0105] The present invention is not limited by the embodiments described above and the attached drawings, but is intended to be limited by the appended claims. Accordingly, various substitutions, modifications, and changes may be made by those skilled in the art within the scope of the technical concept of the present invention as described in the claims, without departing from the technical spirit of the invention, and such are also to be considered to fall within the scope of the present invention.

Claims

Claim 1 An electrode composition for an energy storage device comprising: an active material comprising a carbon material having amorphous and porous properties manufactured by carbonizing black tea, and manganese oxide coated and disposed on the surface of the carbon material with a thickness of 0.01 to 0.03 mm; a conductive material and a binder, wherein the active material is manufactured by mixing the carbon material, manganese(II) acetate tetrahydrate, and potassium permanganate. Claim 2 An electrode composition for an energy storage device according to claim 1, wherein the carbon material is manufactured by performing a process at 700 to 900 ℃ in a non-flammable atmosphere. Claim 3 delete Claim 4 An electrode composition for an energy storage device according to claim 1, comprising, based on the total weight, 70 to 90 weight% of the carbon material, 5 to 15 weight% of a conductive agent, and 5 to 15 weight% of a binder. Claim 5 An energy storage device comprising the electrode composition of claim 1. Claim 6 A method for manufacturing an electrode composition for an energy storage device, comprising the steps of: manufacturing an active material comprising an amorphous and porous carbon material produced by carbonizing black tea; and manganese oxide coated and disposed on the surface of the carbon material with a thickness of 0.01 to 0.03 mm; and adding and mixing a conductive material and a binder to the active material, wherein the step of manufacturing the active material includes the step of coating manganese oxide on the surface of the carbon material, and the step of coating manganese oxide includes the step of mixing the carbon material, manganese(II) acetate tetrahydrate, and potassium permanganate. Claim 7 delete Claim 8 delete

Images