Composite for super capacitor electrode, super capacitor electrode comprising same, and super capacitor

Abstract

One embodiment of the present invention provides a carbon material-activated carbon composite, a super capacitor electrode comprising same, and a super capacitor, the composite comprising activated carbon and a carbon material in which the pore volume of pores having pore diameters of 17Å or less is 30% or less on the basis of the total pore volume.

Description

Composite for electrode of supercapacitor, electrode of supercapacitor and supercapacitor including same

[0001] The present disclosure relates to a composite for an electrode of a supercapacitor, an electrode of a supercapacitor including the composite, and a supercapacitor, and more specifically, to a composite for an electrode of a supercapacitor having a low direct current resistance (ESR). DC ), a composite for an electrode of a supercapacitor for providing a supercapacitor having the characteristics of high power density, high electrode density and high energy density, an electrode of a supercapacitor including the composite, and a supercapacitor.

[0002]

[0003] Recently, electric double layer capacitors (EDLCs), also known as super capacitors, are being considered for application to various systems for efficient energy management, such as electric vehicles (EVs), energy storage systems (ESSs), and renewable energy.

[0004] In particular, supercapacitors can supplement batteries used as the main power source for electric vehicle operation by providing high-power energy required for rapid acceleration of electric vehicles and recovering energy generated instantaneously, thereby enabling commercial operation of electric vehicles.

[0005] Supercapacitors must store enough energy to provide the energy required for driving, and to effectively manage the cost, volume, and weight associated with this, supercapacitors must have very high power density per volume and weight, long life, and low cost.

[0006] Additionally, supercapacitors are increasingly being used as electronic components in the electronics industry due to their performance and characteristics.

[0007] As the power consumption of semiconductors such as complementary metal oxide semiconductors (CMOS) commonly used in various electronic equipment or devices has been minimized, supercapacitors with a capacitance of 1 Farad are attracting attention as memory backup applications because they can replace nickel-cadmium or lithium batteries and provide backup power for several months.

[0008] Compared with conventional electrolytic capacitors, polymer capacitors, tantalum capacitors, etc., supercapacitors use porous activated carbon series electrodes to form a large effective surface area, and store energy in an electric double layer formed at the interface between the electrolyte and the electrode, thereby providing a high volumetric capacitance density (about 10 to 100 times that of conventional capacitors).

[0009] Supercapacitors provide high capacity by forming an electric double layer at the interface between an electrode material with a high surface area, typically activated carbon, and an electrolyte.

[0010] Supercapacitors provide high capacity by forming an electric double layer at the interface between electrode materials with a high specific surface area, typically activated carbon, and an electrolyte, and the capacity is known to be directly proportional to the specific surface area of ​​the electrode material.

[0011] However, there are also technical challenges associated with current supercapacitors.

[0012] Typically, experimentally measured capacitances in supercapacitors based on activated carbon electrodes are much smaller than the theoretical capacitances calculated from the analyzed specific surface area and width of the dipole layer.

[0013] In activated carbons with very high surface areas, the measured capacities are less than about 20% of the theoretical capacities, and this result is related to the presence of micropores (on the order of less than 2 nm), which have wetting deficiencies that prevent the electrolyte from accessing some of the pores, and in which the charged surfaces are separated by about 1 nm to 2 nm (10 Å to 20 Å), an electric double layer cannot be successfully formed.

[0014] Additionally, depending on the carbon source and heat treatment temperature in activated carbon, a large portion of the surface may have the form of micropores that are inaccessible to the liquid electrolyte.

[0015] Despite their high theoretical capacity at the electrode level, activated carbon electrodes do not provide energy storage devices with huge capacities at the supercapacitor cell or pack level.

[0016] Meanwhile, much research is also being conducted to develop electrode materials with improved capacity per volume using porous carbon-based materials such as graphene, carbon nanotube (CNT)-based composites, porous graphite oxide, and porous meso carbon.

[0017] Among these, graphene materials have recently attracted attention for their high thermal conductivity, high electrical conductivity, high strength, and high specific surface area.

[0018] A single graphene sheet has an external surface area of ​​approximately 2,675 m2 / g, in contrast to the approximately 1,300 m2 / g provided by a corresponding single-walled CNT (the inner surface is inaccessible to the electrolyte, and the outer surface is accessible to the liquid electrolyte). Furthermore, the electrical conductivity of graphene is higher than that of CNTs.

[0019] However, individual graphene sheets have a strong tendency to self-stack, reducing the specific surface area accessible to the electrolyte at the electrodes of the supercapacitor.

[0020] Even if individual graphene sheets are partially re-stacked, the resulting multilayer structure should still preferably have interlayer pores of appropriate size. Furthermore, these pores should be sufficiently large to allow electrolyte access and allow for the formation of electric double-layer charges.

[0021] However, the pores or gaps between graphenes must be sufficiently small to ensure a high tap density. The tap density of graphene-based electrodes manufactured by conventional processes is typically less than 0.3 g / cm³, more typically less than 0.2 g / cm³.

[0022] To a large extent, the requirements for large pore size and high porosity levels and the requirements for high tap density are mutually exclusive in supercapacitors.

[0023] Additionally, the manufacturing process to meet the above conditions is very complex and the yield is very low, which causes the price of graphene to rise and makes graphene unsuitable as an electrode material for supercapacitors.

[0024] Another major technical challenge in using graphene sheets as electrode active materials in supercapacitors is forming a thick layer of active material on the surface of a solid current collector (e.g., Al foil) using a conventional graphene-solvent slurry coating process.

[0025] Relatively thick electrodes tend to break easily or be structurally imperfect, and large amounts of binder resin are used to address this, which is exacerbated in the case of electrodes manufactured primarily from graphene.

[0026] It is challenging to create graphene-based electrodes that are thick enough to allow full access to the liquid electrolyte and maintain high porosity to secure sufficient ion storage space. Furthermore, low areal and volume densities lead to low volumetric capacity and low volumetric energy density in supercapacitors.

[0027] Additionally, there is a need to overcome challenges such as the re-stacking of graphene sheets, the requirement for a large proportion of binder resin, and the difficulty in producing thick graphene electrode layers.

[0028] Accordingly, supercapacitors are required that have active materials with high mass loading (areal density), high apparent density (high tap density), thick electrode thickness without significantly reducing electron and ion transport rates, high capacitance, high energy density, and high power density.

[0029] [Prior Art Literature]

[0030] [Patent Document]

[0031] (Patent Document 1) Republic of Korea Patent Publication No. 10-2021-0149993 (December 10, 2021)

[0032] One of the objects of the present invention is to provide a composite for electrodes of a supercapacitor for providing a supercapacitor having low DC resistance, high power density, high electrode density, and excellent capacitance per unit volume (energy density).

[0033]

[0034] The present invention, as one embodiment, provides a composite for an electrode of a supercapacitor, including a carbon material and activated carbon, which includes pores having an optimal diameter range through which solvent molecules of an electrolyte can sufficiently penetrate and a high pore volume, specifically, pores having a pore diameter of 17 Å or less, wherein the pore volume of pores is 30% or less of the total pore volume, an electrode of a supercapacitor including the composite, and a supercapacitor.

[0035]

[0036] The present invention can provide a composite for electrodes of a supercapacitor for providing a supercapacitor having low DC resistance, high power density, high electrode density, and excellent capacitance per unit volume (energy density) as one effect.

[0037]

[0038] Figure 1 shows a carbon material manufactured according to a manufacturing example of the present invention.

[0039] Figure 2 shows the BET analysis results of a carbon material manufactured according to a manufacturing example of the present invention.

[0040] Figure 3 shows the BET analysis results of commercial activated carbon (YP-50).

[0041] Figure 4 shows a Raman spectrum of a carbon material manufactured according to a manufacturing example of the present invention.

[0042] Figure 5 shows the Raman spectrum of commercial graphene.

[0043] Figure 6 shows the results of measuring the electrical conductivity of a carbon material manufactured according to a manufacturing example of the present invention.

[0044] Figure 7 shows the results of electrical conductivity measurement of commercial activated carbon (YP-50).

[0045] Figures 8 to 11 show the TEM analysis results of carbon materials manufactured according to the manufacturing examples of the present invention.

[0046] Figure 12 shows a particle size distribution curve before crushing of a carbon material included in a composite for an electrode of a supercapacitor according to one embodiment of the present invention.

[0047] Figure 13 shows an SEM image before crushing of a carbon material included in a composite for an electrode of a supercapacitor according to one embodiment of the present invention.

[0048] Figure 14 shows a particle size distribution curve after grinding of a carbon material included in a composite for an electrode of a supercapacitor according to one embodiment of the present invention.

[0049] Figure 15 shows an SEM image of a carbon material included in a composite for an electrode of a supercapacitor according to one embodiment of the present invention after pulverization.

[0050]

[0051] The present invention will now be described in detail with reference to the attached drawings. However, it should be noted that the present invention is not limited to the contents described herein or the attached drawings. Those skilled in the art will be able to implement the present invention in various forms, based on the contents described herein and the attached drawings, without departing from the technical spirit of the present invention. It should be understood that such modifications also fall within the scope of the present invention.

[0052]

[0053] A composite for an electrode of a supercapacitor according to one embodiment of the present invention includes a carbon material and activated carbon having the following characteristics.

[0054]

[0055] The pore distribution of the carbon material included in the composite for an electrode of a supercapacitor according to one embodiment of the present invention is such that the pore volume of pores having a pore diameter of 17 Å or less is 30% or less of the total pore volume. More preferably, the pore distribution of the carbon material included in the composite for an electrode of a supercapacitor according to one embodiment of the present invention may be such that the pore volume of pores having a pore diameter of 17 Å or less is 29% or less, 28% or less, 27% or less, 26% or less, 25% or less, or 24% or less of the total pore volume. In addition, the pore distribution of the carbon material included in the composite for an electrode of a supercapacitor according to one embodiment of the present invention may be such that the pore volume of pores having a pore diameter of 17 Å or less is 0% or more, 1% or more, 2% or more, 3% or more, 4% or more, or 5% or more of the total pore volume, or may be 0%.

[0056] At this time, the pore distribution of the carbon material included in the composite for the electrode of the supercapacitor according to one embodiment of the present invention may be such that the pore volume of the pores having a pore diameter of 17Å to 500Å among the pores having a pore diameter exceeding 17Å may be 70% or more, and the average pore diameter may be 20Å to 150Å, more preferably 50Å to 100Å.

[0057] In this specification, the crystal structure of carbon materials is similar to graphite crystals in that the planes are parallel and equally spaced, but it is composed of an imperfect amorphous structure in which the layers are irregularly stacked. This crystal structure forms countless nanometer-sized spaces, and in this specification, these spaces are called pores. The pores are classified into three levels: macropores, mesopores, and micropores, depending on their size, and pores of all sizes exist.

[0058] In this specification, “pore volume” means the total volume of all pores.

[0059] In addition, the specific surface area of ​​the carbon material included in the composite for the electrode of the supercapacitor according to one embodiment of the present invention is 1 m 2 / g to 200m 2 / g is.

[0060] The carbon material included in the composite for the electrode of the supercapacitor according to one embodiment of the present invention has an intensity ratio of the D peak to the G peak as determined by Raman analysis, i.e., the D peak / G peak intensity ratio is 0.1 to 0.9, 0.2 to 0.8, 0.3 to 0.7, or 0.4 to 0.6, and the 2D peak / G peak intensity ratio is 0.5 to 1.5, 0.6 to 1.4, 0.7 to 1.3, 0.8 to 1.2, or 0.9 to 1.1.

[0061] The tap density of the carbon material included in the composite for electrodes of a supercapacitor according to one embodiment of the present invention may be 0.4 g / cm3 to 2.0 g / cm3, more preferably 0.6 g / cm3 to 1.2 g / cm3. Considering that the tap density of general commercial graphene is 0.05 g / cm3 to 0.2 g / cm3, the carbon material included in the composite for electrodes of a supercapacitor according to one embodiment of the present invention has a very high density. The tap density may mean an apparent density obtained by mechanically tapping a measuring container filled with a powder.

[0062] The electrical conductivity of the carbon material included in the composite for electrodes of a supercapacitor according to one embodiment of the present invention is 61 to 76 S / cm, 63 to 74 S / cm, 65 to 72 S / cm, 67 to 70 S / cm, or 68 to 69 S / cm at 2,000 kgf. In addition, the electrical conductivity of the carbon material included in the composite for electrodes of a supercapacitor according to one embodiment of the present invention is 14 to 17 S / cm, 14.5 to 16.5 S / cm, 15 to 16 S / cm, 15.2 to 15.8 S / cm, or 15.4 to 15.6 S / cm at 200 kgf.

[0063] The carbon material included in the composite for electrode of a supercapacitor according to one embodiment of the present invention may have a particle size distribution of 0.01 to 5 ㎛ in D10, 3.1 to 15 ㎛ in D50, and 8.1 to 50 ㎛ in D90. D10, D50, and D90 represent particle sizes corresponding to 10%, 50%, and 90%, respectively, when measuring particle size and accumulating volume from a small particle size, and mean a known unit that indicates the results analyzed through a particle size analyzer, and a further detailed description thereof will be omitted.

[0064] The content of carbon (C) in the carbon material included in the composite for electrode of a supercapacitor according to one embodiment of the present invention may be 98 wt% or more, and more preferably 98.0 wt% or more, 98.1 wt% or more, 98.2 wt% or more, 98.3 wt% or more, 98.4 wt% or more, 98.5 wt% or more, 98.6 wt% or more, or 98.7 wt% or more.

[0065] In addition, the content of oxygen (O) in the carbon material included in the composite for the electrode of the supercapacitor according to one embodiment of the present invention may be less than 2 wt%, and more preferably less than 2.0 wt%, less than 1.9 wt%, less than 1.8 wt%, less than 1.7 wt%, less than 1.6 wt%, less than 1.5 wt%, less than 1.4 wt%, less than 1.3 wt%, less than 1.2 wt%, or less than 1.1 wt%.

[0066] The impurity content included in the carbon material included in the composite for electrode of a supercapacitor according to one embodiment of the present invention may be such that the total content of metals such as iron (Fe) and copper (Cu) is 100 ppm or less, and the total content of alkali metals such as sodium (Na) and calcium (Ca) is 20 ppm or less.

[0067]

[0068] Meanwhile, the carbon material included in the composite for electrode of a supercapacitor according to one embodiment of the present invention can be manufactured from biochar formed by carbonizing biomass.

[0069] The biomass may be a woody biomass, such as at least one of oak, red oak, rice straw, giant reed, sugarcane residue, corn residue, switchgrass, eucalyptus, poplar, palm residue, pine, and energy crops. Preferably, the biomass may be oak, red oak, or a mixture thereof.

[0070] Wood biomass can be processed from regular trees into wood pellets.

[0071] A method for manufacturing a carbon material included in a composite for an electrode of a supercapacitor according to one embodiment of the present invention may include (s1) a step of carbonizing biomass to manufacture biochar, (s2) a step of pulverizing the carbonized biochar, and (s3) a step of removing impurities from the pulverized biochar.

[0072] The step of carbonizing the biomass can be performed by introducing the biomass into a heating zone with different temperature ranges.

[0073] For example, the step of carbonizing biomass may include carbonization steps of 1 to 6, wherein step 1 may be performed at a temperature of 170°C to 200°C, step 2 may be performed at a temperature of 200°C to 280°C, step 3 may be performed at a temperature of 280°C to 500°C, step 4 may be performed at a temperature of 500°C to 700°C, step 5 may be performed at a temperature of 700°C to 800°C, and step 6 may be performed at a temperature of 800°C to 1,100°C, and may be performed for a total time of 3 to 60 minutes.

[0074] Carbonization is the process of heating organic matter to pyrolyze it into a carbon-rich substance. It can be performed while blocking the inflow of oxygen. This is a well-known process, so a more detailed description thereof will be omitted.

[0075] The biochar formed after carbonization has a carbon content of more than 98 wt% and becomes a high-density carbon material.

[0076] At this time, a single-layer carbon material may be formed, but generally, a carbon material with a layered structure having a small number of layers, such as 1.5 layers, 2 layers, 2.5 layers, or 3 layers, is formed.

[0077] The step of crushing carbonized biochar can be performed to ensure that biochar particles of various particle sizes have a predetermined particle size. The biochar can be crushed to an average particle size of 1 μm to 100 μm, and various technologies, such as commonly used ball mills and blade mixers, can be applied without limitation to the specific method of crushing the biochar.

[0078] The step of removing impurities from the pulverized biochar may include only a single impurity removal step, but it may be preferable to include multiple impurity removal steps.

[0079] The first impurity removal step can be performed to remove metal impurities such as iron (Fe) contained in the biochar, and can be performed, for example, by passing the biochar through a magnetic track at a constant flow rate of 1 m / min to 5 m / min.

[0080] Secondary and tertiary impurity removal steps may be performed to further remove more microscopic impurities, and may be performed by sequentially immersing the biochar in an acidic aqueous solution and a basic aqueous solution.

[0081] The secondary impurity removal step can be performed, for example, by immersing the biochar that has passed through the magnetic track in a 10 wt% to 50 wt% hydrochloric acid solution for 1 to 6 hours, then removing the hydrochloric acid component with distilled water in a volume of 200% to 5,000% of the 10 wt% to 50 wt% hydrochloric acid solution, filtering, and drying at a temperature of 60°C to 120°C. The type of acidic aqueous solution is not particularly limited, and various known acidic aqueous solutions other than the hydrochloric acid solution can be used.

[0082] In addition, the third impurity removal step can be performed by, for example, immersing biochar that has been washed with an acidic solution, neutralized with distilled water, and then dried in a 10 wt% to 50 wt% potassium hydroxide solution for 1 to 6 hours, then removing the potassium hydroxide component with distilled water in a volume of 200% to 5,000% of the 10 wt% to 50 wt% potassium hydroxide solution, filtering, and drying at a temperature of 60°C to 120°C. The type of alkaline aqueous solution is not particularly limited, and various known alkaline aqueous solutions other than the potassium hydroxide solution can be used.

[0083] The biochar manufactured through the above-described process exhibits characteristics similar to, yet different from, commercial graphene, and has characteristics suitable for use as an electrode material for supercapacitors.

[0084]

[0085] The activated carbon may be at least one of, but is not limited to, coconut shell-based carbonized activated carbon, phenol resin-based carbonized activated carbon, and coke pitch-based carbonized activated carbon.

[0086]

[0087] In the composite for electrodes of a supercapacitor according to one embodiment of the present invention, the carbon material and the activated carbon may be present in a weight ratio of 1:0.1 to 1 (carbon material:activated carbon), preferably 1:0.2 to 0.8 (carbon material:activated carbon), and more preferably 1:0.3 to 0.55 (carbon material:activated carbon). If the weight ratio of the activated carbon exceeds the aforementioned range, the distribution range of micropores having a diameter of less than 2 nm may increase, making it difficult for the electrolyte to access the pores, and characteristics such as increased resistance, decreased electrode density, and decreased capacity may appear. On the other hand, if the weight ratio of the activated carbon is less than the aforementioned range, the output may be high, but the capacity may be negatively affected. Therefore, it is advantageous to adjust the weight ratio of the activated carbon within the aforementioned range.

[0088]

[0089] Carbon material and activated carbon may be included in an amount of 79 wt% to 95 wt% based on the total weight of the composite for electrodes of a supercapacitor. If the content of carbon material and activated carbon is below the aforementioned range, there may be a negative effect of increased resistance, and if it exceeds the aforementioned range, there may be a negative effect of decreased electrode strength.

[0090]

[0091] In addition, the composite for electrodes of a supercapacitor according to one embodiment of the present invention may further include a conductive additive. The conductive additive may be included in an amount of 2 wt% to 9 wt% based on the total weight of the composite for electrodes of a supercapacitor. The conductive additive may be used as an additive material of the electrode composition to complement the low electrical conductivity of the carbon material, which is similar to graphene in terms of properties, and the low electrical conductivity and high resistance properties of activated carbon. As the conductive additive, carbon black such as ketjen black, acetylene black, or super-p may be used singly or in multiple mixtures.

[0092]

[0093] In addition, the composite for electrodes of a supercapacitor according to one embodiment of the present invention may further include a binder. The binder may be included in an amount of 3 wt% to 12 wt% based on the total weight of the composite for electrodes of a supercapacitor. In addition, at least one of a rubber-based binder such as SBR (styrene butadiene rubber), an elastomer-based binder such as BM400B, and a Teflon-based binder such as polytetrafluoroethylene may be used as the binder.

[0094]

[0095] The composite for electrode of a supercapacitor according to the present invention can be manufactured through a manufacturing method including the following steps to increase electrode density.

[0096] (a1) A step of preparing carbon material, activated carbon, conductive additive and binder, wherein the pore volume of pores having a pore diameter of 17 Å or less is 30% or less of the total pore volume;

[0097] (a2) a step of preparing a conductive additive slurry by mixing the conductive additive with a dispersing agent including a dispersing medium;

[0098] (a3) A step of preparing an electrode composition by mixing the carbon material, the activated carbon, the conductive additive slurry, and the binder;

[0099] (a4) A step of drying the electrode composition to form an electrode solid,

[0100] (a5) a step of crushing the electrode solid, and

[0101] (a6) A step of vacuum drying the above electrode solid.

[0102]

[0103] The carbon material has the same characteristics as those described above in the description of the carbon material included in the composite for the electrode of the aforementioned supercapacitor.

[0104] For example, the carbon material may have a particle size distribution of 0.01 to 5 μm in D10, 3.1 to 15 μm in D50, and 8.1 to 50 μm in D90.

[0105] The activated carbon may have a particle size distribution of 4 to 4.3 ㎛ at D10, 5 to 5.5 ㎛ at D50, and 6 to 6.5 ㎛ at D90. If the particle diameter of the activated carbon is less than the aforementioned range, there may be a problem of a decrease in the specific surface area of ​​the activated carbon. This is because the pore structure inside the particle is destroyed and the surface area is offset, and as a result, after the electrode body is manufactured, the binder invasion range may become relatively wide, which may cause a phenomenon of an increase in resistance and a rapid decrease in electrostatic capacity. On the other hand, if the particle diameter of the activated carbon is more than the aforementioned range, the pores between the particles may increase during the manufacture of the electrode body, which may increase the possibility of cracks, lower the strength of the electrode, and increase the porosity, which may cause a problem of a decrease in the density of the electrode.

[0106]

[0107] Coconut shell-based carbonized activated carbon may have a specific surface area of ​​1,500 to 3,000 m2 / g and a particle size distribution of 3 to 5 μm at D10, 5 to 9 μm at D50, and 9 to 15 μm at D90. Phenol resin-based carbonized activated carbon may have a specific surface area of ​​1,500 to 3,000 m2 / g and a particle size distribution of 5 to 9 μm at D10, 10 to 11 μm at D50, and 11 to 15 μm at D90. Coke pitch-based carbonized activated carbon may have a specific surface area of ​​1,500 to 3,000 m2 / g and a particle size distribution of 5 to 9 μm at D10, 10 to 11 μm at D50, and 11 to 15 μm at D90.

[0108]

[0109] Conductive additives can be used as additives in electrode compositions to compensate for the inherent low electrical conductivity and high resistance of activated carbon. Conductive additives can include single or multiple mixtures of carbon blacks, such as Ketjen black, acetylene black, or Super-P.

[0110]

[0111] As a binder, at least one of a rubber type such as SBR (styrene butadiene rubber), an elastomer type such as BM400B, and a Teflon type binder such as polytetrafluoroethylene can be used.

[0112]

[0113] The step of preparing a conductive additive slurry by mixing a conductive additive with a dispersing agent containing a dispersing medium can be performed by adding the dispersing agent containing the dispersing medium to the conductive additive and performing dispersion stirring using a planetary mixer, a roll mixer, a pigment mixer, or the like. The dispersing agent can be added in an amount of 45 to 60 wt% to 40 to 55 wt% of the conductive additive.

[0114]

[0115] When using an aqueous binder as a dispersion medium, distilled water, isopropyl alcohol, ethanol, or ethyl acetate can be used alone, or distilled water can be mixed with one or two other dispersion mediums. In addition, when using an organic binder such as polyvinylidene fluoride (PVDF), N-methyl-pyrrolidone (NMP) can be used alone as a dispersion medium.

[0116]

[0117] In order to improve dispersibility, the dispersing agent may further include a dispersing agent such as carboxymethylcellulose in addition to the dispersion medium. The dispersing agent may be mixed in a ratio of 0.1 to 1.0 wt% based on the total weight of the dispersing agent. For example, the step of preparing a conductive additive slurry may be performed by mixing a dispersion medium and a dispersing agent to prepare a dispersing agent, adding the prepared dispersing agent to the conductive additive, and then performing dispersion stirring. As a more specific example, the conductive additive slurry may be prepared by mixing carboxymethylcellulose in a composition of 0.1 to 1.0 wt% in a dispersion medium such as distilled water, soft water, or higher alcohol to prepare a dispersing agent, and then adding 45 to 60 wt% of the prepared dispersing agent to 40 to 55 wt% of the conductive additive, and then performing dispersion stirring.

[0118]

[0119] In the step of manufacturing an electrode composition by mixing carbon material, activated carbon, conductive additive slurry, and binder, the carbon material, activated carbon, conductive additive slurry, and binder may be mixed all at once, or may be mixed sequentially. For example, the electrode composition may be manufactured by first mixing the carbon material and activated carbon, then adding the conductive additive slurry to the mixture of the carbon material and activated carbon and mixing them, and finally adding the binder to the mixture of the carbon material, activated carbon, and conductive additive slurry and mixing them. The mixing may be performed by dispersing and stirring using a planetary mixer, a roll mixer, a pigment mixer, or the like.

[0120]

[0121] At this time, the content of the mixture of carbon material and activated carbon, conductive additive slurry, and binder in the electrode composition may be 70 to 85 wt%: 5 to 25 wt%: 4.6 to 5.8 wt% based on the total weight of the electrode composition. In addition, a first binder and a second binder, which are different types of binders, may be mixed and used as the binder, and in this case, the content of the first binder and the second binder may be 0.1 to 0.5 wt%: 4.5 to 5.3 wt% based on the total weight of the electrode composition. The first binder may be a rubber-based SBR (styrene butadiene rubber) binder or an elastomer-based BM400B binder, and the second binder may be a Teflon-based polytetrafluoroethylene binder, and may be a binder that is introduced later. For example, the electrode composition can be manufactured in a semi-solid state by mixing 15 to 25 wt% of a conductive additive slurry with 70 to 80 wt% of a mixture of carbon material and activated carbon, performing primary dispersion stirring using a planetary mixer, a roll mixer, a pigment mixer, etc., then adding 0.1 to 0.5 wt% of the manufactured primary slurry and 0.1 to 0.5 wt% of a rubber-based SBR (styrene butadiene rubber) or an elastomer-based BM400B binder to a stirrer, performing secondary dispersion stirring, and then adding 4.5 to 5.3 wt% of a Teflon-based polytetrafluoroethylene binder into the stirrer, and performing a third dispersion stirring.

[0122]

[0123] The mixing ratio of the carbon material and the activated carbon may be a weight ratio of 1:0.1 to 1 (carbon material:activated carbon), preferably a weight ratio of 1:0.2 to 0.8 (carbon material:activated carbon), and more preferably a weight ratio of 1:0.3 to 0.55 (carbon material:activated carbon). If the weight ratio of the activated carbon exceeds the aforementioned range, the distribution range of micropores having a diameter of less than 2 nm may increase, making it difficult for the electrolyte to access the pores, and characteristics such as increased resistance, decreased electrode density, and decreased output may appear. On the other hand, if the weight ratio of the activated carbon is less than the aforementioned range, a negative effect of decreased capacity may appear. Therefore, it is advantageous to adjust the weight ratio of the activated carbon within the aforementioned range.

[0124]

[0125] The mixing of carbon material and activated carbon can be performed by mixing and dispersing using a planetary mixer, a pigment mixer, etc. At this time, by rotating and dispersing at a high speed of 300 revolutions per minute (300 rpm) or higher, the carbon material and activated carbon can be overlapped at a close distance.

[0126]

[0127] The step of drying the electrode composition may be performed to remove moisture from the external and internal surfaces of the manufactured electrode composition, and may be performed at a temperature of, for example, 60°C to 150°C. At this time, moisture on the surface of the electrode composition may be completely removed, but some of it may not be completely removed and may remain.

[0128]

[0129] In the step of grinding the electrode solids, the electrode solids are ground into a powder or granule state. Grinding can be performed using a blade mixer, etc.

[0130]

[0131] The step of vacuum drying the electrode solid can be performed to remove moisture inside the pores, and can be performed at a temperature of, for example, 150°C to 200°C.

[0132]

[0133] According to the present invention, by mixing and using a carbon material having a specific pore distribution and activated carbon as electrode materials at a certain weight ratio, the resistance of the electrode can be minimized, and the inter-particle void ratio can be minimized during electrode manufacturing while simultaneously maximizing the electrode density.

[0134] The present invention can control the particle size distribution of an electrode material by controlling the particle size distribution of the electrode material before grinding and thereby improving the accuracy of the particle size distribution of the electrode solid after grinding, thereby further maximizing the density of the electrode.

[0135]

[0136] Meanwhile, in the wet coating method of coating a slurry-state electrode composition on the surface of a metal current collector such as aluminum, drying occurs together with the coating, so when the slurry dries, migration occurs in which the binder contained in the slurry intensively floats to the upper surface of the electrode as the vaporized dispersion solvent moves, which increases the resistance of the electrode surface. In addition, since the moisture inside the electrode must be removed while it is wound in a roll shape during the manufacturing process, there is a problem in that the moisture that has penetrated into the pores inside the winding (core) cannot be completely removed. On the other hand, in the present invention, since the electrode solid content in the powder or granule state is directly vacuum-dried, even the moisture inside the pores can be removed, and since migration does not occur, it is possible to prevent a decline in electrical performance and an increase in internal pressure due to the decomposition of moisture that occurs during long-term use of the supercapacitor.

[0137]

[0138] In addition, according to another embodiment of the present invention, a composite film for an electrode of a supercapacitor formed by pressing a composite for an electrode of a manufactured supercapacitor can be provided.

[0139]

[0140] Pressurizing of the electrode composite of a vacuum-dried powder or granule state of a supercapacitor can be performed using a heating roll press, etc. Pressurizing can be performed once alone, or can be performed multiple times, such as twice or three times. Among these, it may be preferable to press the electrode composite three times. The first pressing can be performed by maintaining the roll surface temperature of the heating roll press at 40°C to 120°C, while putting the electrode composite in the powder or granule state between rolls and pressing it to form an electrode composite film having a thickness of 170 to 200 μm. The second pressing can be performed by maintaining the roll surface temperature of the heating roll press at 40°C to 120°C, while putting the electrode composite film formed by the first pressurization between rolls and pressing it to form an electrode composite film having a thickness of 80 to 120 μm. The third pressurization may be performed by placing the second press-formed electrode composite film between rolls and pressurizing it while maintaining the roll surface temperature of the heating roll press at room temperature of 25℃, thereby pressurizing and forming it into an electrode composite film having a thickness of 50 to 80㎛. The third roll pressurization can be performed at room temperature to minimize the thickness deviation of the electrode composite film.

[0141]

[0142] In addition, according to another embodiment of the present invention, an electrode of a supercapacitor can be provided including a composite film for an electrode of a supercapacitor manufactured according to another embodiment of the present invention.

[0143]

[0144] An electrode of a supercapacitor according to another embodiment of the present invention can be manufactured through a manufacturing method including the following steps.

[0145] (b1) a step of manufacturing a conductive layer paste,

[0146] (b2) a step of manufacturing an electrode current collector having a conductive layer formed by coating the conductive layer paste on a metal foil and drying it;

[0147] (b3) a step of vacuum drying the electrode current collector on which the conductive layer is formed, and

[0148] (b4) A step of placing and pressing an electrode composite film on an electrode current collector on which the conductive layer is formed so as to face the conductive layer.

[0149]

[0150] The conductive layer paste is intended to bond the electrode composite film to the electrode current collector, and includes a slurry of a carbon material having excellent electrical conductivity and a conductive additive, and may further include a binder. The conductive paste may be prepared, for example, by mixing a carbon material and a conductive additive slurry, performing primary dispersion stirring using a planetary mixer, a roll mixer, a pigment mixer, etc., and then adding a binder to the primary slurry thus prepared and performing secondary dispersion stirring. At this time, the carbon material, the conductive additive slurry, and the binder may be mixed in a ratio of 10 to 20 wt%: 70 to 90 wt%: 5 to 10 wt%. The carbon material and the conductive additive slurry may be the same as the carbon material and the conductive additive slurry included in the composite for the electrode of the supercapacitor described above, and a detailed description thereof will be omitted. The binder may also be the same as the binder included in the composite for the electrode of the supercapacitor described above, and for example, rubber-based SBR (styrene butadiene rubber) or elastomer-based BM400B may be used. The viscosity of the manufactured conductive layer paste may be 10,000 to 100,000 cP, and the sheet resistance may be 0.5 Ω / cm3 to 5.0 Ω / cm3.

[0151]

[0152] In the step of manufacturing an electrode current collector having a conductive layer formed thereon by coating a conductive layer paste on a metal foil and drying it, the coating can be performed by a known method such as a doctor blade, a comma roll, gravure, or spray coating. The conductive layer paste can be coated on one or both sides of the metal foil. The coating thickness during coating can be adjusted so that the thickness of the conductive layer formed after drying is 1 to 10 μm, and can be coated to a thickness of, for example, 10 to 50 μm. The metal foil can be an aluminum foil or an etched aluminum foil, and the thickness of the metal foil can be, but is not limited to, 5 to 50 μm. The drying can be performed at a temperature of, for example, 40°C to 120°C.

[0153]

[0154] The step of vacuum drying the electrode current collector on which the conductive layer is formed can be performed to remove moisture, and can be performed at a temperature of, for example, 150°C to 200°C.

[0155]

[0156] In the step of forming an electrode by arranging an electrode composite film on an electrode current collector on which a conductive layer is formed so as to face the conductive layer and pressing the electrode, the pressing may be performed using a heating roll press or the like. For example, the step may be performed by arranging an electrode composite film on one or both sides of an aluminum current collector on which a conductive layer is formed on one or both sides, and pressing and forming the electrode composite film once while maintaining the roll surface temperature of the heating roll press at 40°C to 120°C. The thickness of the electrode after pressing may be 85% or more of the total thickness of the electrode composite film before pressing and the thickness of the electrode current collector on which the conductive layer is formed. If the thickness of the electrode after pressing is less than the above range, it may be difficult for the electrolyte to penetrate into the pores, which may cause a loss of electrical performance of the supercapacitor, and the expansion rate of the electrode may increase during charge and discharge of the supercapacitor, which may increase the possibility of cracking of the separator.

[0157]

[0158] The electrode of a supercapacitor manufactured by the method for manufacturing a supercapacitor electrode according to the present invention can have a high electrode density of 0.85 to 1.65 g / cm3 and a low electrode surface resistance of 1 to 200 Ω / sqm. Accordingly, the supercapacitor electrode according to the present invention can be formed with a thinner thickness compared to other electrodes having the same electrostatic capacity, and can exhibit a high output density due to the high electrostatic capacity and low resistance characteristics due to the high electrode density compared to other electrodes having the same thickness or volume.

[0159]

[0160] In addition, according to another embodiment of the present invention, a supercapacitor including an electrode of a supercapacitor manufactured according to another embodiment of the present invention can be provided.

[0161]

[0162] Hereinafter, the present invention will be described in more detail through examples and comparative examples.

[0163]

[0164] Meanwhile, the following manufacturing examples and examples are merely for explaining the present invention and do not represent all of the technical ideas of the present invention. Therefore, it should be understood that there may be various equivalents and modified examples that can replace the following manufacturing examples and examples at the time of filing this application.

[0165]

[0166] Manufacturing example: Manufacturing of carbon materials

[0167] According to the steps (s1) to (s3) described above, a carbon material was manufactured from biochar formed by carbonizing oak as biomass. In this case, in step (s1), all of the carbonization steps 1 to 6 described above were performed, in step (s2), the biochar was pulverized using a ball mill, and in step (s3), all of the first to third impurity removal steps described above were performed.

[0168] In the carbon material manufactured according to the manufacturing example, the pore volume of pores having a pore diameter of 17 Å or less was measured to be 23.39% of the total pore volume.

[0169] In addition, the specific surface area of ​​the carbon material manufactured according to the manufacturing example was 62.55 m2 / g, and the particle size distribution was 3.4 μm at D10, 5.9 μm at D50, and 9.1 μm at D90.

[0170] Additionally, the tap density of the carbon material manufactured according to the manufacturing example was 1.6 g / cm3.

[0171] Referring to Fig. 4, the D peak / G peak intensity ratio and the 2D peak / G peak intensity ratio measured by Raman analysis of the carbon material manufactured according to the manufacturing example were 0.49 and 1.045, respectively, indicating that it has a single or several layered structure. On the other hand, referring to Fig. 5, the D peak / G peak intensity ratio and the 2D peak / G peak intensity ratio measured by Raman analysis of commonly sold commercial graphene were 1.16 and 0.32, respectively, indicating that it has strong crystallinity and a single or more (or several) layered structure.

[0172] Referring to Fig. 6, the electrical conductivity of the carbon material manufactured according to the manufacturing example showed a value of 68.687 S / cm at 2,000.5 kgf. On the other hand, referring to Fig. 7, the electrical conductivity of activated carbon (YP-50, Kuraray), which is commonly used as an electrode material for supercapacitors, showed a value of 5.384 S / cm at 1,999 kgf, which can be seen to be 10% or less lower than the electrical conductivity of the carbon material manufactured according to the manufacturing example.

[0173] In addition, as can be seen from the TEM analysis results in FIGS. 8 to 11 and Table 1 below, the carbon (C) content in the carbon material manufactured according to the manufacturing example of the present invention was measured to be 98.72 wt%, and the oxygen (O) content was measured to be 1.09 wt%.

[0174]

[0175] Elemental Weight Ratio (wt%) wt% Sigma Elemental Ratio (Atomic %) C98.720.0699.1N000O1.090.060.82Na000Si0.180.020.08S000 Total:100 100

[0176] Table 1: TEM analysis results of carbon materials according to the manufacturing example of the present invention.

[0177] Example 1: Preparation of composite for electrode of supercapacitor

[0178] Example 1-1

[0179] A dispersing agent was prepared with a composition of distilled water and 0.2 wt% of carboxymethylcellulose (the amount of the dispersing agent is such that the proportion of carboxymethylcellulose is 0.2 wt% based on the total mass of the powdered conductive additive, powdered carbon material, activated carbon, and binder), and the prepared dispersing agent was added to 10 wt% of the powdered conductive additive super-P, followed by dispersion stirring using a planetary mixer to prepare a conductive additive slurry.

[0180] A pore volume of pores with a pore diameter of 17Å or less, which accounts for 23.39% of the total pore volume, was added to the manufactured conductive additive slurry. A powdered carbon material having a particle size distribution of 3.4㎛ at D10, 5.9㎛ at D50, and 9.1㎛ at D90 and a mixed powder of coconut shell-based carbonized activated carbon (YP-50) having a specific surface area of ​​1,500㎡ / g and a particle size distribution of 3㎛ at D10, 7㎛ at D50, and 15㎛ at D90 were added, and dispersion stirring was performed using a planetary mixer to prepare a solid slurry. At this time, the powdered carbon material and the activated carbon were added at a weight ratio of 8:2 (carbon material:activated carbon) and 85 wt% based on the total weight of the electrode composition to prepare a solid slurry.

[0181] The manufactured solid slurry of 95.2 wt% (dispersing agent 0.2 wt%, powdered conductive additive 10 wt%, powdered carbon material and activated carbon 85 wt%) and a binder of 0.3 wt% of SBR were placed in a stirrer and subjected to secondary dispersion stirring. After mixing with a binder of 4.5 wt% of polytetrafluoroethylene, a third dispersion stirring was performed, thereby producing a semi-solid electrode composition.

[0182] The manufactured electrode composition was dried at a temperature of 100°C, and the electrode solid from which moisture had been removed was ground into granules using a blade mixer. Next, the granule-shaped electrode solid was vacuum-dried at a temperature of 150°C to manufacture a composite for a supercapacitor electrode.

[0183]

[0184] Example 1-2

[0185] A composite for a supercapacitor electrode was manufactured in the same manner as in Example 1-1, except that the weight ratio of carbon material and activated carbon was mixed at 7:3.

[0186]

[0187] Example 1-3

[0188] A composite for a supercapacitor electrode was manufactured in the same manner as in Example 1-1, except that the weight ratio of carbon material and activated carbon was mixed at 6:4.

[0189]

[0190] Example 1-4

[0191] A composite for a supercapacitor electrode was manufactured in the same manner as in Example 1-1, except that the weight ratio of carbon material and activated carbon was mixed at 5:5.

[0192]

[0193] Comparative Example 1-1

[0194] A dispersing agent was prepared with a composition of distilled water and 0.2 wt% of carboxymethylcellulose, and the prepared dispersing agent was added to 5 wt% of powdered conductive additive super-P (the amount of the dispersing agent was such that the proportion of carboxymethylcellulose was 0.2 wt% based on the total mass of the powdered conductive additive, powdered carbon material, activated carbon, and binder), and then dispersion stirring was performed using a planetary mixer to prepare a conductive additive slurry.

[0195] In the manufactured slurry of the conductive additive, the pore volume of pores having a pore diameter of 17 Å or less is 86% of the total pore volume, and 90 wt% of coconut shell-based carbonized activated carbon (YP-50) powder having a specific surface area of ​​1,500 m2 / g and a particle size distribution of 3 ㎛ at D10, 7 ㎛ at D50, and 15 ㎛ at D90 is added, and dispersion stirring is performed using a planetary mixer to manufacture a solid slurry.

[0196] The manufactured solid slurry and SBR binder of 0.3 wt% were placed in a stirrer and subjected to secondary dispersion stirring, then mixed with polytetrafluoroethylene binder of 4.5 wt% and subjected to a third dispersion stirring, thereby producing a semi-solid electrode composition.

[0197] The manufactured electrode composition was dried at a temperature of 100°C, and the electrode solid from which moisture had been removed was ground into a powder using a blade mixer. Next, the powdered electrode solid was vacuum-dried at a temperature of 150°C to manufacture activated carbon electrode powder.

[0198]

[0199] Example 2: Preparation of composite film for electrode of supercapacitor

[0200] Example 2-1

[0201] While maintaining the roll surface temperature of the heating roll press at 80°C, the composite film for electrodes of a supercapacitor according to Example 1-1 was placed between the rolls and subjected to a first press molding to a thickness of 180 to 190 μm. Next, while maintaining the roll surface temperature of the heating roll press at 40°C, the composite film for electrodes of a supercapacitor subjected to a first press molding to a thickness of 100 to 110 μm was subjected to a second press molding to a thickness of 100 to 110 μm. Thereafter, while maintaining the roll surface temperature of the heating roll press at room temperature of 25°C, the composite film for electrodes of a supercapacitor subjected to a second press molding to a thickness of 60 μm was subjected to a third press molding to produce a composite film for electrodes of a supercapacitor.

[0202]

[0203] Example 2-2

[0204] In addition to using the composite for the electrode of a supercapacitor according to Example 1-2, a composite film for the electrode of a supercapacitor was manufactured in the same manner as in Example 2-1.

[0205]

[0206] Example 2-3

[0207] In addition to using the composite for the electrode of a supercapacitor according to Example 1-3, a composite film for the electrode of a supercapacitor was manufactured in the same manner as in Example 2-1.

[0208]

[0209] Example 2-4

[0210] A composite film for the electrode of a supercapacitor was manufactured in the same manner as in Example 2-1, except that the composite for the electrode of a supercapacitor according to Example 1-4 was used.

[0211]

[0212] Comparative Example 2-1

[0213] While maintaining the roll surface temperature of the heating roll press at 80°C, the activated carbon electrode powder according to Comparative Example 1-1 was placed between the rolls, and the first press molding was performed to a thickness of 200 to 210 μm. Next, while maintaining the roll surface temperature of the heating roll press at 60°C, the first press molded activated carbon film was secondarily press molded to a thickness of 100 to 110 μm. Thereafter, while maintaining the roll surface temperature of the heating roll press at room temperature of 25°C, the second press molded activated carbon film was thirdly press molded to a thickness of 80 to 85 μm, thereby manufacturing an activated carbon film.

[0214]

[0215] Example 3: Fabrication of electrodes for supercapacitors

[0216] Example 3-1

[0217] According to the manufacturing example, 13 wt% of the carbon material powder was mixed with 80 wt% of the conductive additive slurry prepared in Example 1-1, and after the first dispersion stirring was performed with a planetary mixer, the prepared first slurry and 7 wt% of SBR binder were added to the stirrer and the second dispersion stirring was performed, thereby preparing a conductive layer paste having a viscosity of 60,000 cP. The prepared conductive layer paste was coated with a thickness of 15 μm on one side of an 18 μm aluminum foil using a doctor blade, dried at a temperature of 100°C to form a conductive layer having a thickness of 4 μm, and then vacuum-dried at a temperature of 150°C to remove moisture. A composite film according to Example 2-1 was placed on the aluminum current collector on which the conductive layer was formed, and pressurized once while maintaining the roll surface temperature of the heating roll press at 80°C.

[0218] The total thickness of the electrode of the completed supercapacitor after roll pressing was 78 μm, and the electrode density was 1.17 g / cm3. The specific capacity was calculated as 56 μm, which is the total thickness of the electrode of the supercapacitor, 78 μm, excluding the thickness of the electrode current collector, 22 μm, on which the conductive layer was formed.

[0219]

[0220] Example 3-2

[0221] Aside from using the composite film for the electrode of the supercapacitor according to Example 2-2, the electrode of the supercapacitor was manufactured in the same manner as in Example 3-1.

[0222] The total thickness of the electrode was 80 μm and the electrode density was 1.10 g / cm3. The specific capacity was calculated as 60 μm, excluding the 20 μm thickness of the electrode current collector where the conductive layer was formed from the total thickness of the 80 μm electrode of the supercapacitor.

[0223]

[0224] Example 3-3

[0225] Aside from using the composite film for the electrode of the supercapacitor according to Example 2-3, the electrode of the supercapacitor was manufactured in the same manner as in Example 3-1.

[0226] The total thickness of the electrode was 80 μm and the electrode density was 1.04 g / cm3. The specific capacity was calculated as 60 μm, excluding the 20 μm thickness of the electrode current collector where the conductive layer was formed from the total thickness of the electrode of the supercapacitor of 80 μm.

[0227]

[0228] Example 3-4

[0229] Aside from using the composite film for the electrode of the supercapacitor according to Example 2-4, the electrode of the supercapacitor was manufactured in the same manner as in Example 3-1.

[0230] The total thickness of the electrode was 92 μm, and the electrode density was 0.99 g / cm3. The specific capacity was calculated as 70 μm, excluding the 20 μm thickness of the electrode current collector where the conductive layer was formed from the total thickness of the 92 μm electrode of the supercapacitor.

[0231]

[0232] Comparative Example 3-1

[0233] According to the manufacturing example, 80 wt% of the carbon material powder was mixed with 13 wt% of the conductive additive slurry manufactured in Comparative Example 1-1, and after the first dispersion stirring was performed with a planetary mixer, the manufactured first slurry and 7 wt% of SBR binder were added to the stirrer and the second dispersion stirring was performed, thereby manufacturing a conductive layer paste having a viscosity of 60,000 cP. The manufactured conductive layer paste was coated with a thickness of 15 μm on one side of an 18 μm aluminum foil using a doctor blade, dried at a temperature of 100°C to form a conductive layer having a thickness of 4 μm, and then vacuum-dried at a temperature of 150°C to remove moisture. An activated carbon film according to Comparative Example 2-1 was placed on the aluminum current collector on which the conductive layer was formed, and pressurized once while maintaining the roll surface temperature of the heating roll press at 80°C.

[0234] That is, except that the conductive additive slurry manufactured in Comparative Example 1-1 and the activated carbon film of the supercapacitor according to Comparative Example 2-1 were used, the electrode of the supercapacitor was manufactured in the same manner as in Example 3-1.

[0235] The total thickness of the completed activated carbon electrode body after roll pressing was 125 μm, and the electrode density was 0.64 g / cm3. The specific capacity was calculated as 103 μm, excluding the 22 μm thickness of the electrode current collector where the conductive layer was formed from the total thickness of 125 μm of the activated carbon electrode body.

[0236]

[0237] Experimental Example: Fabrication and Evaluation of a Supercapacitor

[0238] The electrodes according to Examples 3-1 to 3-4 and Comparative Example 3-1 were processed with a punch to produce coin-shaped electrodes with a diameter of 16 mm. Next, an insulating gasket made of polypropylene (PP) was placed between the metal cases of the positive and negative electrodes, each made of SUS metal, to prevent short circuits due to contact between metal cases of different polarities and leakage of the liquid electrolyte present inside the unit cell. Then, a certain amount of a 0.1 N concentration organic electrolyte containing acetonitrile as a solvent and tetraethylammonium tetrafluoroborate (TEABF4) as a solute was impregnated onto the surfaces of the electrodes located inside the metal cases of the positive and negative electrodes, and a separator made of a porous nonwoven fabric was placed between the electrodes to prevent short circuits due to contact between electrodes of different polarities. After that, in order to implement effective airtightness, the outermost edge of the lower metal case, which is the part that is directly crimped, the outermost edge of the gasket that is in close contact with the outermost edge of the lower metal case, and the outermost edge of the upper metal case that is in close contact with the inner edge of the outermost edge of the gasket were crimped while pressing from the outermost edge of the lower metal case to the cell center using a crimping mold, thereby manufacturing a unit cell.

[0239] For each supercapacitor including the electrode manufactured according to the examples and comparative examples, a test was conducted under the conditions that the charging voltage was 2.7 V, the charging current was the same as the discharge current, the charging time was 1 hour after the charging voltage reached 2.7 V, and the discharge current was 1 mA. At this time, the electrode surface resistance, electrode resistivity, leakage current (LC), and alternating current resistance (ESR) were measured. AC ), electrostatic resistance (ESR) DC ), electrostatic capacity (CAP) and specific capacity were measured, and the results are shown in Table 2 below.

[0240] In the table below, Experimental Examples 1 to 4 and Comparative Experimental Example 1 represent the measurement results of supercapacitors including electrodes manufactured according to Examples 3-1 to 3-4 and Comparative Example 3-1, respectively.

[0241]

[0242] Item Electrode Surface Resistance Electrode Resistivity LCESR AC ESR DC CAP capacity unit (Ω / sqm)(S / cm)(㎃)(Ω)(Ω)(F)(F / ㎤)Experimental example 150.21.320.111.165.90.2511.10Experimental example 268.50.930.221.206.30.3414.09Experimental example 3107.80.610.351.306.80.4217.41Experimental example 4153.10.380.381.406.90.4214.92Comparative experimental example 11,374.00.200,393.4612.260.4310.38

[0243] The outputs of each of Experimental Examples 1 to 4 and Comparative Experimental Example 1 are as shown in Table 3 below.

[0244] Item Output Electrode Weight Output Density Unit (W) (g) (kW / kg) Experimental Example 10.30890.02211.73 Experimental Example 20.28930.02410.90 Experimental Example 30.26800.02410.68 Experimental Example 40.26410.0289.48 Comparative Experimental Example 10.14870.0415.61

[0245] At this time, the output can be calculated with the following function.

[0246] P = V 2 / (4*ESR DC )

[0247] Here, P is power, V is voltage, and ESR DC is the DC resistance, and the unit of output is W. This shows that under the same voltage conditions, the smaller the DC resistance, the better the output.

[0248]

[0249] In the case of an example in which a specific carbon material and activated carbon are mixed and used as electrode materials for a supercapacitor, compared to a comparative example in which activated carbon is used alone, an electrode having low DC resistance and high density is provided, thereby enabling the capacity and output of the supercapacitor to be designed to complement each other, that is, while improving the output of the supercapacitor, the capacity can also be secured at a certain level, and a technology for controlling the final performance is provided, and by manufacturing carbon materials using biochar manufactured by carbonizing biomass, an economic effect can also be provided.

[0250]

[0251] While one embodiment of the present invention has been exemplified above, it is not intended to limit the scope of the present invention to the aforementioned embodiments. Those skilled in the art will be able to appropriately modify one embodiment of the present invention, including omitting, modifying, or replacing all or part of the configuration of the present invention, or adding other configurations, without departing from the technical spirit of the present invention, by referring to this specification and the attached drawings.

[0252]

[0253] The terms and expressions in this specification should be interpreted broadly and not in a restrictive sense. As used herein, the term "includes" does not exclude the presence or addition of one or more other components other than the mentioned components. Furthermore, as used herein, the term "to" includes upper and lower limits. For example, "1 to 10" includes the upper limit of 10 and the lower limit of 1, and can also be expressed as "1 or more and 10 or less."

[0254]

[0255] Each of the embodiments exemplarily described herein can be combined with one another, and unless contradictory, the content described in a specific embodiment can be equally applied to other embodiments even if not described in the other embodiments.

Claims

1. Carbon material having a pore volume of pores having a pore diameter of 17 Å or less and a pore volume of 30% or less of the total pore volume; and Containing activated carbon; Composite for electrodes of supercapacitors.

2. In paragraph 1, The weight ratio of the carbon material and the activated carbon is 1:0.1 to 1. Composite for electrodes of supercapacitors.

3. In paragraph 1, The above carbon material is manufactured from biochar formed by carbonizing biomass. Composite for electrodes of supercapacitors.

4. In paragraph 1, The above carbon material has a carbon (C) content of 98 wt% or more and an oxygen (O) content of less than 2 wt%. Composite for electrodes of supercapacitors.

5. In paragraph 1, The D peak / G peak intensity ratio by Raman analysis of the above carbon material is 0.1 to 0.9, and the 2D peak / G peak intensity ratio is 0.5 to 1.

5. Composite for electrodes of supercapacitors.

6. In paragraph 1, The tap density of the above carbon material is 0.4 g / cm3 or more and 2.0 g / cm3 or less. Composite for electrodes of supercapacitors.

7. In paragraph 1, The electrical conductivity of the above carbon material is 61 S / cm to 76 S / cm at 2,000 kgf. Composite for electrodes of supercapacitors.

8. In paragraph 1, The above carbon material is D 10 1 to 5㎛, D 50 10 to 15㎛, D 90 having a particle size distribution of 8.1 to 50㎛, Composite for electrodes of supercapacitors.

9. In paragraph 1, The specific surface area of ​​the above carbon material is 1 m 2 / g to 200m 2 / g is, Composite for electrodes of supercapacitors.

10. In paragraph 1, Containing more challenging additives, Composite for electrodes of supercapacitors.

11. In paragraph 1, Including more binders, Composite for electrodes of supercapacitors.

12. A composite for electrode of a supercapacitor according to Article 1, Electrodes of a supercapacitor.

13. In paragraph 12, The above electrode has a density of 0.85 to 1.65 g / cm3, Electrodes of a supercapacitor.

14. Containing the electrode of the supercapacitor according to Article 12, Supercapacitor.

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