Method for manufacturing activated carbon material for supercapacitors

Abstract

Providing activated carbon materials for supercapacitors. [Solution] The method includes the steps of: heating heavy hydrocarbon oil at 2 atm to 3 atm and 460°C to 500°C for more than 4 hours to cause a coking reaction and obtaining a soft carbon precursor having a QI value of 95 to 98 wt%, a TI value of 89 to 91 wt%, and an intermediate phase structure ratio of more than 50 vol%; grinding and sorting the soft carbon precursor to obtain a finely powdered soft carbon precursor with an average particle size of 0.3 to 5 mm; mixing the finely powdered soft carbon precursor and a solid activator in a weight ratio of 0.25 to 0.5 without introducing a solvent to obtain a mixture; heating the mixture to cause an activation reaction and a carbonization reaction to obtain a first carbonaceous component containing a first activated carbon and a residual activator; removing the residual activator to obtain a second carbonaceous component; grinding and sorting the second carbonaceous component to obtain a third carbonaceous component; and heating the third carbonaceous component to obtain an activated carbon material for supercapacitors.

Description

[Technical Field]

[0001] This invention relates to a method for producing carbon materials, and more particularly to a method for producing activated carbon materials for supercapacitors. [Background technology]

[0002] Supercapacitors, also known as electric double-layer capacitors, are widely known in the industry as electrochemical capacitors with high energy density, and their capacity and performance fall between that of conventional electrolytic capacitors and storage batteries.

[0003] Furthermore, supercapacitors have a fast charge / discharge rate and a long cycle life, making them a key component in power supply systems.

[0004] Currently, carbon materials are commonly used as electrode materials for supercapacitors. These carbon materials can be produced by subjecting heavy hydrocarbon oil, which is sold cheaply at oil refineries, to multiple manufacturing processes. As a result, the economic value of the cheap heavy hydrocarbon oil also increases.

[0005] Patent Document 1 discloses a method for manufacturing carbon material for supercapacitors, which includes steps a to c in order.

[0006] In step a, the charcoal raw material is heat-treated at a temperature between 150°C and 650°C for 10 to 20 hours to obtain the heat-treated charcoal raw material.

[0007] The coal raw material is selected from the group consisting of coal-tar pitch, petroleum coke pitch, mesocarbon microbeads (MCMB), and combinations thereof, and has an average particle size between 5 μm and 50 μm.

[0008] In step b, the heat-treated char material and a strong base (potassium hydroxide, hereinafter abbreviated as "KOH") are uniformly mixed and reacted at a temperature of 820°C to 1020°C for 5 to 10 hours to obtain alkali-activated char material. The weight ratio of the strong base to the heat-treated char material is between 1.5 and 3.0.

[0009] In step c, the alkali-activated carbon raw material is repeatedly washed with sulfuric acid (H2SO4) as a cleaning agent to remove residual KOH, and then dried and pulverized in sequence to obtain the carbon material for supercapacitors described in Patent Document 1.

[0010] The carbon material for supercapacitors manufactured by the manufacturing method described in Patent Document 1 has a specific surface area (hereinafter referred to as "BET") of 1400 m². 2 / g~2650m 2 The ratio is between / g, and the proportion of BETs with pore diameters less than 0.7nm is between 30% and 52%, which is advantageous for improving the specific capacitance (F / cc) of the supercapacitor. [Prior art documents] [Patent Documents]

[0011] [Patent Document 1] Taiwan Patent No. I822169 [Overview of the project] [Problems that the invention aims to solve]

[0012] In light of the above-mentioned conventional technologies, improving the manufacturing method of activated carbon materials to increase the BET of activated carbon materials and improve the specific capacitance of supercapacitors is a challenge in the related technological field.

[0013] The objective of the present invention is to provide a method for producing activated carbon material for supercapacitors that can increase BET (Break-Effect Testing). [Means for solving the problem]

[0014] The present invention comprises step A, in which a heavy hydrocarbon oil is heated at a pressure in the range of 2 atm to 3 atm and a temperature in the range of 460°C to 500°C for at least 4 hours to induce a coking reaction, thereby obtaining a soft carbon precursor in which the value of quinoline-insoluble components is in the range of 95 wt% to 98 wt% and the value of toluene-insoluble components is in the range of 89 wt% to 91 wt%, and Step B involves grinding and sorting the aforementioned soft carbon precursor to obtain a finely powdered soft carbon precursor with an average particle size in the range of 0.3 mm to 5 mm. Step C involves mixing the pulverized soft carbon precursor and a solid activator under conditions without introducing a solvent to obtain a mixture. Step D involves heating the mixture to cause an activation reaction and a carbonization reaction to obtain a first carbonaceous component containing the first activated carbon and the remaining activator. Step E involves removing the residual activator from the first carbonaceous component to obtain a second carbonaceous component, Step F involves grinding and separating the second carbonaceous component to obtain a third carbonaceous component, The process includes step G, which involves heating the third carbonaceous component to obtain an activated carbon material for a supercapacitor, In step A, the proportion of the intermediate phase structure (mesophase) contained in the soft carbon precursor exceeds 50 vol%, The present invention provides a method for producing activated carbon material for supercapacitors, characterized in that, in step C, the weight ratio of the pulverized soft carbon precursor to the solid activator is between 0.25 and 0.5. [Effects of the Invention]

[0015] The manufacturing method of the activated carbon material for supercapacitor of the present invention has a high BET of the manufactured activated carbon material, and when a carbon electrode sheet is manufactured using the activated carbon material and a supercapacitor is assembled thereby, the supercapacitor also has a high energy density, a high output density, and an excellent weight specific capacity.

Brief Description of Drawings

[0016] [Figure 1] It is an image of a soft carbon precursor obtained in Step A of Specific Example 1 (E1) of the activated carbon material for supercapacitor of the manufacturing method of the present invention taken with a polarizing microscope (hereinafter abbreviated as "PM"). [Figure 2] It is a graph showing the relationship between the specific surface area and the average particle diameter of the pulverized soft carbon precursor, explaining the specific surface areas of the activated carbon materials for supercapacitor obtained in Specific Example 1 (E1), Specific Example 2 (E2), and Specific Example 3 (E3) of the manufacturing method of the present invention. [Figure 3] It is a graph showing the relationship between the specific surface area and the average particle diameter of the pulverized soft carbon precursor, explaining the specific surface areas of the activated carbon materials for supercapacitor obtained in Specific Example 4 (E4), Specific Example 5 (E5), and Specific Example 6 (E6) of the manufacturing method of the present invention. [Figure 4] It is a graph showing the relationship between the weight specific capacity (F / g) and the discharge current density, explaining the weight specific capacities at different current densities when measuring supercapacitors are assembled using the activated carbon materials for supercapacitor obtained in Specific Example 3c (E3c) and Specific Example 6c (E6c) of the manufacturing method of the present invention, respectively. [Figure 5] It is a graph showing the relationship between the energy density and the output density, explaining the electrical properties of the measuring supercapacitors of Specific Example 3c (E3c) and Specific Example 6c (E6c) according to the manufacturing method of the present invention.

Modes for Carrying Out the Invention

[0017] The present invention will be described in detail below.

[0018] The embodiment of the method for producing activated carbon material for supercapacitors according to the present invention includes steps A to G.

[0019] In step A, heavy hydrocarbon oil is heated at a pressure in the range of 2 atm to 3 atm and a temperature in the range of 460°C to 500°C for at least 4 hours to induce a coking reaction, thereby obtaining a soft carbon precursor having a quinoline insoluble content (hereinafter abbreviated as "QI value") in the range of 95 wt% to 98 wt% and a toluene insoluble content (hereinafter abbreviated as "TI value") in the range of 89 wt% to 91 wt%.

[0020] In step A, assuming a total volume of 100 vol% for the soft carbon precursor, the proportion of the intermediate phase structure contained in the soft carbon precursor exceeds 50 vol%.

[0021] More specifically, in process A, heavy hydrocarbon oil is first transported to a reactor (not shown), and heat treatment is performed on the heavy hydrocarbon oil for more than 4 hours under the above temperature and pressure conditions to decompose and condensation polymerize the heavy hydrocarbon oil in the reactor, thereby obtaining a soft carbon precursor.

[0022] In step B, the soft carbon precursor is ground and sorted to obtain a finely powdered soft carbon precursor. In step B, the sorted finely powdered soft carbon precursor has an average particle size in the range of 0.3 mm to 5 mm.

[0023] In step C, the pulverized soft carbon precursor and the solid activator are mixed under conditions without the introduction of a solvent to obtain a mixture.

[0024] In step C, the weight ratio of the pulverized soft carbon precursor to the solid activator is between 0.25 and 0.5, meaning the weight ratio of the pulverized soft carbon precursor to the solid activator is within the range of 1:4 to 1:2.

[0025] In order to improve the degree of particle size matching between the pulverized soft carbon precursor and the solid activator during mixing, in step C of some embodiments, a pulverized soft carbon precursor with an average particle size in the range of 1 mm to 5 mm is used, and the solid activator has an average particle size in the range of 8 mm to 10 mm.

[0026] Specifically, grinding and pulverization of the solid activator are not performed; in other words, there is no need to grind and pulverize the solid activator. In step C of this embodiment, the solid activator is an alkaline agent, and potassium hydroxide (KOH) is described as an example, but it is not limited to that.

[0027] In step D, the mixture is heated to induce an activation reaction and a carbonization reaction, thereby obtaining a first carbonaceous component containing the first activated carbon and the remaining activator.

[0028] In step D of this embodiment, the mixture is heated to 700°C to 900°C in a nitrogen atmosphere at a heating rate of 1°C / min to 10°C / min.

[0029] In step D of some embodiments, the mixture is heated to 400°C to 500°C in a nitrogen atmosphere at a heating rate of 1°C / min to 10°C / min and maintained for 4 to 6 hours (first heating stage), and then heated to 700°C to 900°C at the same heating rate and maintained for at least 1 hour (second heating stage).

[0030] In step E, the residual activator in the first carbonaceous component is removed to obtain the second carbonaceous component. In step E, sub-steps E1, E2, E3, and E4 are carried out in order.

[0031] Specifically, in sub-step E1, first purified water is introduced into the first carbonaceous component to obtain an alkaline aqueous solution containing first activated carbon and residual activator dissolved in the first purified water. In this embodiment, sub-step E1 is carried out for at least 1 hour.

[0032] In sub-step E2, a first acidic aqueous solution containing an acidifying agent is introduced into an alkaline aqueous solution. The residual activator in the alkaline aqueous solution and the acidifying agent in the first acidic aqueous solution undergo a neutralization reaction to produce a salt, and a second acidic aqueous solution is produced with a pH higher than that of the first acidic aqueous solution. The second acidic aqueous solution contains a second activated carbon and the salt dissolved in the second acidic aqueous solution. In this embodiment, sub-step E2 is carried out for at least 1 hour, and the concentration of the acidifying agent in the first acidic aqueous solution is in the range of 0.8 M to 2 M.

[0033] The acidifying agent in the first acidic aqueous solution applied to the present invention is selected from the group consisting of sulfuric acid (H2SO4), nitric acid (HNO3), hydrochloric acid (HCl), and combinations thereof.

[0034] In sub-process E3, a second purified water is introduced into a second acidic aqueous solution to obtain a final solution containing a third activated carbon and having a pH of 7.

[0035] In sub-step E4, water is removed from the final solution to obtain a second carbonaceous component. Specifically, in sub-step E4, the final solution is left to stand overnight until the third activated carbon settles, then the water in the upper layer is removed, and the solution is heated at a temperature of 100°C to 150°C for at least 4 hours to obtain the second carbonaceous component.

[0036] The second and third activated carbons are activated carbons treated with acid. Depending on the pH value of the second acidic aqueous solution, in some embodiments, the second and third activated carbons may be activated carbons with different degrees of acid treatment, while in some embodiments, the second and third activated carbons may be activated carbons with the same degree of acid treatment.

[0037] Furthermore, since the pulverized soft carbon precursor and the solid activator (i.e., alkaline agent) are mixed directly, the resulting mixture will have a very high pH value.

[0038] Therefore, the purpose of performing sub-process E1 before sub-process E2 is to lower the pH value of the mixture with the first purified water, thereby obtaining an alkaline aqueous solution in sub-process E1 with a pH value much lower than that of the mixture. This significantly reduces the heat dissipation due to the neutralization reaction between the alkaline aqueous solution and the first acidic (strong acid) aqueous solution, thereby reducing the risk when performing process E.

[0039] In step F, the second carbonaceous component is ground and separated to obtain a third carbonaceous component.

[0040] In this invention, specifically, after grinding the second carbonaceous component, a third carbonaceous component is selected from the second carbonaceous component, having a particle size distribution D50 particle size between 8 μm and 12 μm, a particle size distribution D10 particle size between 2 μm and 6 μm, and a particle size distribution D90 particle size between 14 μm and 20 μm.

[0041] More specifically, in step F of this embodiment, a cyclone-type classifying device (manufacturer: NPK, model number: MDS-3) is used to select a second carbonaceous component that has been ground, and from the second carbonaceous component, a third carbonaceous component is selected in which the particle size distribution D50 has a particle size between 8 μm and 10 μm, the particle size distribution D10 has a particle size between 2 μm and 4 μm, and the particle size distribution D90 has a particle size between 14 μm and 16 μm.

[0042] In step G, the third carbonaceous component is heated to obtain activated carbon material for supercapacitors. In step G of some embodiments, the material is heated to a temperature of less than 1000°C in a nitrogen atmosphere at a heating rate of 1°C / min to 10°C / min.

[0043] In process G, the activated carbon material for the supercapacitor has a plurality of micropores and a plurality of mesopores whose pore diameter is larger than that of the micropores, and the ratio of the total volume of the micropores to the total volume of the mesopores is in the range of 1.5 to 5.

[0044] The specific manufacturing method of the present invention, the activated carbon material for supercapacitors manufactured by the method, the carbon electrodes manufactured using the activated carbon material, the supercapacitor assembled using the carbon electrodes, and the electrical characteristics of the supercapacitor will be explained by manufacturing specific examples according to the comparative examples below and the manufacturing methods of the embodiments described above.

[0045] <Method for manufacturing activated carbon material for supercapacitors> <Raw materials used in the manufacture of activated carbon materials for supercapacitors> The raw materials used in the manufacture of activated carbon materials for supercapacitors are listed below.

[0046] Heavy hydrocarbon oil obtained by CPC Corporation (Taiwan) after petroleum refining.

[0047] Solid KOH purchased from Supelco, model number EMSURE.

[0048] H2SO4, which was purchased from Honeywell under the brand name Fluka.

[0049] HNO3, a brand purchased from Honeywell, is under the name Fluka.

[0050] Specific example 1 (E1) Specific example 1 (E1) of the method for producing activated carbon material for supercapacitors of the present invention involves heating heavy hydrocarbon oil at a pressure in the range of 2 atm to 3 atm and a temperature of 480°C for more than 4 hours to induce a coking reaction and obtain a soft carbon precursor (corresponding to step A).

[0051] Finely powdered soft carbon precursors were obtained by grinding and sorting the soft carbon precursor of Specific Example 1 (E1), and these finely powdered soft carbon precursors were divided into four groups: Specific Example 1a (E1a) with an average particle size of less than 0.3 mm, Specific Example 1b (E1b) with an average particle size of 1 mm, Specific Example 1c (E1c) with an average particle size in the range of 2 mm to 3 mm, and Specific Example 1d (E1d) with an average particle size in the range of 3 mm to 5 mm (corresponding to step B).

[0052] Then, the respective finely powdered soft carbon precursors E1a, E1b, E1c, and E1d were mixed with solid KOH (in a ratio of 1:2) to obtain the respective mixtures of E1a, E1b, E1c, and E1d (corresponding to step C).

[0053] The mixture of E1a, E1b, E1c, and E1d was heated to 800°C at a heating rate of 3°C / min, and then maintained at this temperature for 1 hour to induce an activation reaction and a carbonization reaction, yielding the first carbonaceous components of E1a, E1b, E1c, and E1d, each containing the first activated carbon and residual KOH (corresponding to step D).

[0054] The first purified water was continuously introduced into each of the first carbonaceous components for at least one hour to obtain alkaline aqueous solutions E1a, E1b, E1c, and E1d, each containing the first activated carbon and residual KOH dissolved in the first purified water (corresponding to sub-step E1).

[0055] A first acidic aqueous solution containing 1 M H2SO4 and 1 M HNO3 is continuously introduced into each alkaline aqueous solution for at least 1 hour, causing a neutralization reaction between the residual KOH in each alkaline aqueous solution and the H2SO4 and HNO3 in the first acidic aqueous solution to produce potassium nitrate (KNO3) and potassium sulfate (K2SO4), and second acidic aqueous solutions E1a, E1b, E1c, and E1d are produced, each with a pH higher than that of the first acidic aqueous solution. Each second acidic aqueous solution contains the respective second activated carbon and the KNO3 and K2SO4 dissolved in the respective second acidic aqueous solution (corresponding to sub-step E2).

[0056] Second purified water was continuously introduced into each of the second acidic aqueous solutions to obtain final solutions E1a, E1b, E1c, and E1d, each containing a third activated carbon and having a pH of 7 (corresponding to sub-step E3).

[0057] Each final solution was allowed to stand overnight until the third activated carbon in each solution settled. After removing the water from the upper layer, the solutions were heated at a temperature of 100°C to 150°C for at least 4 hours to obtain the second carbonaceous components E1a, E1b, E1c, and E1d (corresponding to sub-step E4).

[0058] By grinding and separating each of the second carbonaceous components, third carbonaceous components E1a, E1b, E1c, and E1d were obtained (corresponding to step F).

[0059] Each third carbonaceous component was heated for 30 minutes at a heating rate of 10°C / min to obtain the activated carbon materials for supercapacitors E1a, E1b, E1c, and E1d (corresponding to process G).

[0060] <Comparative example 1 (CE1)> Regarding Comparative Example 1 (CE1) of the method for producing activated carbon material for supercapacitors, the ground and sorted finely powdered soft carbon precursor is similar to that of Specific Example 1 (E1), except that the particle size of particle size distribution D50 is 5.11 μm, the particle size of particle size distribution D10 is 2.04 μm, and the particle size of particle size distribution D90 is 9.59 μm.

[0061] <Comparative Example 2 (CE2)> Comparative Example 2 (CE2) of the method for producing activated carbon material for supercapacitors is similar to Comparative Example 1 (CE1), except that the solid KOH was ground to an average particle size of 5 μm.

[0062] Specific examples 2a(E2a), 2b(E2b), 2c(E2c), 2d(E2d), 3a(E3a), 3b(E3b), 3c(E3c), 3d(E3d), 4a(E4a), 4b(E4b), 4c(E4c), 4d(E4d), 5a(E5a), 5b(E5b), 5c(E5c), 5d(E5d), 6a(E6a), 6b(E6b), 6c(E6c), and 6d(E6d) of the method for manufacturing activated carbon material for supercapacitors of the present invention are similar to Specific Example 1(E1), and for the sake of brevity of the specification, the differences are summarized in Table 1.

[0063] [Table 1]

[0064] <Evaluation of soft carbon precursors and activated carbon materials for supercapacitors> The QI value was measured in accordance with ASTM D7280-06 (2011) for soft carbon precursors obtained by the E1 manufacturing method.

[0065] The TI value was measured in accordance with ASTM D4312-95a (2010) for soft carbon precursors obtained by the E1 manufacturing method.

[0066] Using a polarizing microscope (manufacturer: Nikon, model: Eclipse LV100POL), soft carbon precursors obtained by the E1 manufacturing method were imaged to obtain PM images of the soft carbon precursors (as shown in Figure 1). Then, in accordance with ASTM D4616-95 (2013), the soft carbon precursors in Figure 1 were analyzed to calculate the proportion of intermediate phase structures in the soft carbon precursors obtained by the E1 manufacturing method.

[0067] BET measurement: BET measurement is performed using an adsorption analyzer (Manufacturer: Micromeritics Instrument Corp., Model: ASAP). TMUsing 2020M), the activated carbon materials for supercapacitors obtained by the manufacturing methods of each comparative example (CE1 and CE2) and each specific example (E1a-E1d, E2a-E2d, E3a-E3d, E4a-E4d, E5a-E5d, and E6a-E6d) were measured. In the measurement, adsorption and desorption analysis was performed using nitrogen, and the amount of adsorption (V, cm) was measured. 3 The relationship between nitrogen (p / g) and the relative pressure of nitrogen (P / P0) at equilibrium pressure was determined. The BET adsorption isothermal relationship, which has formula 1, was used for the measurements.

[0068]

number

[0069] In formula 1, P represents the equilibrium pressure, P0 represents the saturated vapor pressure, C represents the BET constant, V represents the amount of adsorption when the gas is at equilibrium pressure, and Vm represents the saturated adsorption amount when the gas forms a monolayer.

[0070] Then, a graph of P / V(P0-P) for P / P0 within the range of 0 to 1 was created, and the slope (C-1 / CVm) and intercept (1 / CVm) of the graph were calculated to obtain a graph showing the relationship between each adsorption amount and relative pressure. Then, the specific surface area (S) was calculated using formula 2. BET ) was calculated.

[0071]

number

[0072] In formula 2, Nm represents the number of adsorbed gas molecules, N represents Avogadro's number, σ represents the adsorption cross-sectional area for adsorbing gas molecules, and ν represents the amount of gas adsorbed at equilibrium pressure.

[0073] Using the curves in the graph showing the relationship between the obtained adsorption amounts and their relative pressures, we applied the analytical model of heterogeneous surface-2-dimension non-localized density functional theory (HS-2D-NLDFT) to determine the BET of mesopores and micropores.

[0074] Measurement of the total volume of the pores (unit: cm) 3 / g): The total volume of the pores was measured using the adsorption analyzer described above. The activated carbon materials for each comparative example and each specific example of supercapacitors were measured, and graphs of the nitrogen adsorption-desorption relationship between the adsorption amount (V) and relative pressure (P / P0) when the gas was at equilibrium pressure were obtained.

[0075] The curves in each nitrogen adsorption / desorption relationship graph were applied to the HS-2D-NLDFT analytical model to calculate the total pore volume of the activated carbon material for supercapacitors in each comparative example and specific example.

[0076] Measurement of micropore distribution: The distribution of micropores was measured using the nitrogen adsorption / desorption relationship graph described above, in conjunction with the HS-2D-NLDFT analytical model, to calculate the micropore distribution of the activated carbon materials for supercapacitors in each comparative example and specific example.

[0077] Measurement of mesopore distribution: The distribution of mesopores was measured using the nitrogen adsorption / desorption relationship graph described above, in conjunction with the HS-2D-NLDFT analytical model, to calculate the distribution of mesopores in the activated carbon materials for supercapacitors of each comparative example and each specific example.

[0078] The ratio of the total volume of micropores to the total volume of mesopores: The ratio of the total volume of micropores to the total volume of mesopores was calculated using the values ​​obtained from the measurement of the total pore volume of the activated carbon materials for supercapacitors in each comparative example and each specific example, and the ratio of the total volume of micropores was calculated using Formula 3 below.

[0079] Formula 3: (Vμ / Vtotal)×100%

[0080] In formula 3, Vμ represents the total volume of micropores with a width of 2 nm or less, and Vtotal represents the total volume of pores. The ratio of mesopores is obtained by subtracting the ratio of micropores from 100%.

[0081] In Figure 1, which shows the PM image of the E1 soft carbon precursor, the black areas represent the in-phase structure of each soft carbon precursor, and the gray areas represent the intermediate phase structure of each soft carbon precursor. According to ASTM D4616-95 (2013), the proportion of the intermediate phase structure calculated from the analysis of the PM image of the E1 soft carbon precursor is 52 vol% (as shown in Table 2).

[0082] [Table 2]

[0083] According to Table 2, the TI value obtained by measuring the soft carbon precursor of E1 in accordance with ASTM D4312-95a (2010) was 89.9 wt%, and the QI value obtained by measuring the soft carbon precursor of E1 in accordance with ASTM D7280-06 (2011) was 96.4 wt%.

[0084] As can be seen from Figure 2, the BET of the activated carbon material for supercapacitors produced by the manufacturing methods E1, E2, and E3 of the present invention tends to increase with increasing amounts of solid activator, and also tends to increase with improving the average particle size of the finely powdered soft carbon precursor. The maximum BET (~2250m) is obtained when the ratio of parts by weight of finely powdered soft carbon precursor to parts by weight of solid activator is 1:4. 2 It has / g).

[0085] When electrodes are made and supercapacitors are assembled using each of the activated carbon materials for supercapacitors of the present invention, it is advantageous for improving the output density and weight specific capacitance of the supercapacitor.

[0086] As can be seen from FIG. 3, the BET of the activated carbon materials for supercapacitors produced by the production methods of E5 and E6 of the present invention tends to increase with the amount of the solid activator used, and also tends to increase with the improvement of the average particle size of the micronized soft carbon precursor.

[0087] The BET of the activated carbon materials for supercapacitors produced by the production methods of E5 and E6 of the present invention is the largest BET (i.e., ~2160 m 2 / g and ~2800 m 2 / g) when the ratio of the weight part of the micronized soft carbon precursor to the weight part of the solid activator is 1:4 and the average particle size of the micronized soft carbon precursor is 2 mm to 3 mm, respectively. Also, when the average particle size of the micronized soft carbon precursor is 3 mm to 5 mm, the corresponding BET tends to decrease.

[0088] According to the result, when electrodes are made and supercapacitors are assembled using the activated carbon material for supercapacitors by E6c of the present invention, it is advantageous for improving the output density and weight specific capacitance of the supercapacitor.

[0089] The BET of the activated carbon materials for supercapacitors produced by the production methods of CE1 and CE2 is ~846 m 2 / g and ~2632 m 2 / g as a result of measurement.

[0090] In the production method of CE2, by adopting a micronized soft carbon precursor with a particle size of D50 of 5.11 μm, a particle size of D10 of 2.04 μm, and a particle size of D90 of 9.59 μm and mixing it with solid KOH having an average particle size of about 5 μm, the BET was improved to ~2632 m 2 / g, but the complexity of the production method increased.

[0091] After completing the activated carbon material for supercapacitors using the above manufacturing method, the applicant used the E3c and E6c activated carbon materials for supercapacitors, along with the activated carbon material for supercapacitors with model number ASC20 (hereinafter referred to as Comparative Example 3 (CE3)) and the activated carbon material for supercapacitors with model number ASC25 (hereinafter referred to as Comparative Example 4 (CE4)) from CHINA STEEL CHEMICAL CORPORATION of Taiwan, to manufacture electrode slurries and carbon electrode sheets, respectively, and assembled a measuring supercapacitor using each carbon electrode sheet.

[0092] <Raw materials for electrode slurry> The raw materials for the electrode slurry are listed below.

[0093] Carboxymethyl cellulose powder (hereinafter abbreviated as "CMC powder") purchased from JSR Corporation and with model number JSR-104A.

[0094] Conductive carbon black purchased from Timcal, with the product name Super P.

[0095] Styrene-butadiene rubber (hereinafter abbreviated as "SBR") purchased from Nippon Paper Industries Co., Ltd., with the model number MAC350HC.

[0096] Activated carbon materials for supercapacitors of types E3c, E6c, ASC20, and ASC25 (hereinafter abbreviated as "AC").

[0097] <Manufacturing of electrode slurry> CMC powder was added to deionized water (12 ml by volume) and homogenized at room temperature for 30 minutes using a homogenizer (manufacturer: IKA GmbH, Germany, model: RW20) to completely dissolve the CMC powder in the deionized water, obtaining a highly viscous and completely transparent solution.

[0098] Then, Super P was added to the solution and homogenized for 30 minutes, and AC was added to the solution and homogenized for approximately 150 minutes until AC was completely dispersed in the solution.

[0099] Finally, SBR was added to the solution and homogenized for about 15 minutes to obtain an electrode slurry.

[0100] The weight percentages (wt%) of CMC, SBR, Super P, and AC in the electrode slurry are summarized in Table 3 below, and the weight of the dried powders (i.e., CMC, SBR, Super P, and AC) used in the manufacture of the electrode slurry was 0.2 g.

[0101] [Table 3]

[0102] <Raw materials for carbon electrode sheets> The raw materials for carbon electrode sheets are listed below.

[0103] Aluminum foil purchased from Nippon Energy Storage Industry Co., Ltd., with model number 30C054.

[0104] <Manufacturing of carbon electrode sheets> An electrode slurry was placed in a blade coater (manufacturer: Yasuda Seiki Seisakusho, model number: No. 542-AB-H) with a gap width set to 150 μm, and the electrode slurry was uniformly applied to aluminum foil used as an aluminum current collector to obtain an electrode coating layer.

[0105] Then, the electrode coating layer and the aluminum current collector plate were placed in a vacuum oven (manufacturer: DENGYNG INSTRUMENTS CO., LTD., Taiwan; model number: DOV-30) and heated at a temperature of 110°C for at least 4 hours to completely evaporate the moisture in the electrode coating layer.

[0106] Then, the dried electrode coating layer and the aluminum current collector plate were placed in a rolling mill (manufacturer: UBIQ TECHNOLOGY CO., LTD., Taiwan; model number: RL-1500) and rolled at a rolling rate in the range of 30% to 40% to form a carbon electrode layer on the aluminum current collector plate with a thickness in the range of 40 μm to 50 μm, thereby constituting a carbon electrode with the carbon electrode layer and the aluminum current collector plate.

[0107] Finally, the carbon electrode was cut into multiple carbon electrode sheets.

[0108] Each carbon electrode sheet has a working area (1.0 cm x 1.0 cm) and a welding area that protrudes outward from the working area.

[0109] <Materials for supercapacitors> The raw materials for supercapacitors are listed below.

[0110] Triethylmethylammonium tetrafluoroborate (hereinafter abbreviated as "TEMABF4") purchased from Tokyo Chemical Industry Co., Ltd., with model number T2198.

[0111] Propylene carbonate (hereinafter abbreviated as "PC") purchased from Sigma, Inc., USA, with model number 107913.

[0112] Aluminum tab leads (tableads) purchased from UBIQ TECHNOLOGY CO., LTD. in Taiwan, with a thickness of 0.1 mm, a width of 3 mm, and a length of 65 mm.

[0113] Nickel tab leads purchased from UBIQ TECHNOLOGY CO., LTD. of Taiwan, with a thickness of 0.1 mm, a width of 3 mm, and a length of 65 mm.

[0114] A separator purchased from UNION CHEMICALIND. CO., LTD. of Taiwan, with model number TF40-30, to be used as a separator membrane for a supercapacitor.

[0115] <Assembly of Supercapacitors> By using two carbon electrode sheets as a set, each set is used as the positive electrode sheet and negative electrode sheet for each measuring supercapacitor.

[0116] First, the carbon electrode layer in the welding area of ​​each set of positive and negative electrode sheets was thoroughly wiped away. Then, using an ultrasonic spot welding apparatus (manufacturer: SHENG-CING INSTRUMENTS CO.,LTD., Taiwan, model number: MSK-800), aluminum tab leads were welded to the welding area of ​​each set of positive electrode sheets, and nickel tab leads were welded to the welding area of ​​the negative electrode sheet. The opposite surface of the portion of each aluminum tab lead and each nickel tab lead corresponding to the welding area was covered with a plastic film.

[0117] Then, each set of positive and negative electrode sheets was wrapped and enclosed while placing multiple separator films of appropriate size between the working areas of the positive and negative electrode sheets of each set.

[0118] Then, the separator membranes, each containing the rolled-up positive and negative electrode sheets, were placed in separate plastic bags and vacuum-dried to remove any remaining moisture from the positive and negative electrode sheets.

[0119] Then, each plastic bag containing the positive electrode sheet, negative electrode sheet, and separator membrane of each set was placed in a glove box under an argon (Ar) atmosphere, and electrolyte (containing TEMABF4 and PC, with a TEMABF4 concentration of 1M) was dropped into each plastic bag to completely permeate the positive electrode sheet, negative electrode sheet, and separator membrane.

[0120] Finally, using a vacuum packaging machine (manufacturer: SHENG-CING INSTRUMENTS CO.,LTD., Taiwan, model: MSK-115A-S), the openings of each plastic bag were sealed so that each aluminum tab lead and each nickel tab lead was reliably exposed outside the plastic bag, and the plastic film on each aluminum tab lead and each nickel tab lead was sealed inside the plastic bag so that it was aligned with the opening of the plastic bag, thereby obtaining each supercapacitor for measurement.

[0121] <Capacitor Performance Test> Measurement of gravimetric capacitance (unit: F / g): The specific capacitance by weight (unit: F / g) was measured using a cell test system (manufacturer: Solartron Analytical, UK, model number: Model 1470E) on E3c, E6c, CE3, and CE4 supercapacitors.

[0122] First, the positive and negative electrode sheets of each measurement supercapacitor were activated by cyclic voltammetry (hereinafter abbreviated as "CV").

[0123] The scan speed for cyclic voltammetry is 50 mV / s, and the scan voltage for cyclic voltammetry is 0V to 2.7V.

[0124] Then, each measurement supercapacitor was charged with a current density of 2 A / g.

[0125] Then, constant current discharge measurements were performed on the E3c, E6c, CE3, and CE4 supercapacitors at current densities of 2 A / g and 100 A / g and voltages in the range of 0 V to 2.7 V. Additionally, one constant current charge-discharge measurement was performed on the E3c and E6c supercapacitors at current densities of 0.5 A / g, 1.0 A / g, 4.0 A / g, 10 A / g, 12.5 A / g, 20 A / g, 25 A / g, 50 A / g, 75 A / g, and 100 A / g and voltages in the range of 0 V to 2.7 V.

[0126] Finally, the weight-to-capacitance ratio of each measurement supercapacitor was calculated using the following formula 4.

[0127] Formula 4: Weight specific capacity = 4×I×td / (M×△V)

[0128] In formula 4, I represents the discharge rate, td represents the discharge time (seconds), M represents the weight of the carbon electrode layer in the electrode sheet of each measuring supercapacitor, and △V represents the potential difference after subtracting the internal resistance drop (hereinafter abbreviated as "IRdrop").

[0129] According to Figure 4, the corresponding weight-specific capacitances of the E3c and E6c measuring supercapacitors of the present invention under high current density (100 A / g) measurement conditions reach ~100 F / g and ~72 F / g, respectively.

[0130] As shown in Figure 5, which is obtained by combining Figure 4, the E3c and E6c measuring supercapacitors of the present invention reach an energy density of ~30 Wh / kg at a power density of 10 K, and the E3c measuring supercapacitor reaches an energy density of ~10 Wh / kg at a power density of 80 K. Therefore, the E3c and E6c measuring supercapacitors of the present invention have excellent weight-specific capacitance, energy density, and power density under measurement conditions of 100 A / g.

[0131] According to Table 4, the bets for CE3 and CE4 were 2000m each. 2 / g and 2790m 2 / g, and the BET of E3c and E6c of the present invention (each 2338m 2 / g and 2823m 2 This corresponds to / g).

[0132] [Table 4]

[0133] The weight-to-capacitance ratios of the CE3 and CE4 measuring supercapacitors under a 2A / g measurement condition are only 109F / g and 119F / g, respectively. In contrast, the weight-to-capacitance ratio of the E3c measuring supercapacitor of the present invention under a 2A / g measurement condition is 121F / g, which is higher than that of CE3, and the weight-to-capacitance ratio of the E6c measuring supercapacitor of the present invention under a 2A / g measurement condition is 111F / g, which is close to that of CE4.

[0134] Furthermore, the weight-to-weight capacitance of the CE3 measuring supercapacitor under a measurement condition of 100 A / g was only ~85 F / g, while the weight-to-weight capacitance of the E3c measuring supercapacitor of the present invention under a measurement condition of 100 A / g was 100 F / g, which is higher than that of CE3, and the weight-to-weight capacitance of the E6c measuring supercapacitor of the present invention under a measurement condition of 100 A / g also reached ~72 F / g.

[0135] According to these results, the corresponding weight-to-capacitance ratios of the E3c measuring supercapacitor of the present invention under 2A / g or 100A / g measurement conditions are all superior to the weight-to-capacitance ratios of the CE3 measuring supercapacitor, the corresponding weight-to-capacitance ratio of the E6c measuring supercapacitor of the present invention under 2A / g measurement conditions is 111F / g, which is close to the weight-to-capacitance ratio of CE4, and the corresponding weight-to-capacitance ratio of the E6c measuring supercapacitor of the present invention under 100A / g measurement conditions can reach ~72F / g.

[0136] Therefore, the manufacturing method of the present invention can increase the economic value of heavy hydrocarbon oils that are sold cheaply.

[0137] According to the above, the method for producing activated carbon material for supercapacitors of the present invention can increase the economic value of inexpensive heavy hydrocarbon oil, and the BET of the produced activated carbon material is high. Furthermore, when carbon electrode sheets are produced and a supercapacitor is assembled using this material, the supercapacitor also has high energy density, high power density, and excellent weight-to-weight capacity, thus reliably achieving the objectives of the present invention.

[0138] The above embodiments are illustrative in illustrating the principles and effects of the present invention and do not limit it. A person skilled in the art can make some modifications and alterations to the above embodiments, provided that they do not deviate from the spirit and scope of the invention. Therefore, all modifications and alterations made by a person skilled in the art, provided that they do not deviate from the spirit of the invention, should also be considered to fall within the scope of protection of the present invention. [Industrial applicability]

[0139] The method for producing activated carbon materials of the present invention is particularly suitable for producing activated carbon materials for supercapacitors.

Claims

1. Step A involves heating heavy hydrocarbon oil at a pressure in the range of 2 atm to 3 atm and a temperature in the range of 460°C to 500°C for at least 4 hours to induce a coking reaction, thereby obtaining a soft carbon precursor in which the value of quinoline-insoluble components is in the range of 95 wt% to 98 wt% and the value of toluene-insoluble components is in the range of 89 wt% to 91 wt%. Step B involves grinding and sorting the aforementioned soft carbon precursor to obtain a finely powdered soft carbon precursor having an average particle size in the range of 0.3 mm to 5 mm. Step C involves mixing the finely powdered soft carbon precursor and a solid activator under conditions without introducing a solvent to obtain a mixture. Step D involves heating the mixture to cause an activation reaction and a carbonization reaction to obtain a first carbonaceous component containing the first activated carbon and the remaining activator. Step E involves removing the residual activator from the first carbonaceous component to obtain a second carbonaceous component, Step F involves grinding and separating the second carbonaceous component to obtain a third carbonaceous component, The process includes step G, which involves heating the third carbonaceous component to obtain an activated carbon material for a supercapacitor. In step A, with the total volume of the soft carbon precursor being 100 vol%, the proportion of the intermediate phase structure contained in the soft carbon precursor exceeds 50 vol%. A method for producing activated carbon material for supercapacitors, characterized in that, in step C, the weight ratio of the pulverized soft carbon precursor to the solid activator is between 0.25 and 0.

5.

2. The method for producing activated carbon material for a supercapacitor according to claim 1, characterized in that, in step C, the solid activator has an average particle size in the range of 8 mm to 10 mm.

3. The method for producing activated carbon material for supercapacitors according to claim 1, characterized in that, in step C, the solid activator is not ground or pulverized.

4. The method for producing an activated carbon material for a supercapacitor according to claim 1, characterized in that in step C, the finely powdered soft carbon precursor having an average particle size in the range of 1 mm to 5 mm is used.

5. The method for producing an activated carbon material for a supercapacitor according to claim 1, characterized in that in step D, the material is heated to 700°C to 900°C in a nitrogen atmosphere at a heating rate of 1°C / min to 10°C / min.

6. The method for producing activated carbon material for supercapacitors according to claim 1, characterized in that in step D, the material is heated to 400°C to 500°C in a nitrogen atmosphere at a heating rate of 1°C / min to 10°C / min, maintained for 4 to 6 hours, and then heated to 700°C to 900°C at the same heating rate and maintained for at least 1 hour.

7. In step C, the solid activator is an alkaline agent, and in step E, sub-steps E1, E2, E3, and E4 are carried out in order. In the sub-step E1, first purified water is introduced into the first carbonaceous component to obtain an alkaline aqueous solution containing the first activated carbon and the residual activator dissolved in the first purified water. In the sub-step E2, a first acidic aqueous solution containing an acidifying agent is introduced into the alkaline aqueous solution, causing a neutralization reaction between the residual activator in the alkaline aqueous solution and the acidifying agent in the first acidic aqueous solution to produce a salt, and a second acidic aqueous solution having a pH higher than that of the first acidic aqueous solution is produced. The second acidic aqueous solution contains a second activated carbon and the salt dissolved in the second acidic aqueous solution. In the aforementioned sub-step E3, a second purified water is introduced into the second acidic aqueous solution to obtain a final solution containing a third activated carbon and having a pH of 7. The method for producing activated carbon material for a supercapacitor according to claim 1, characterized in that, in the sub-step E4, water is removed from the final solution to obtain the second carbonaceous component.

8. The method for producing activated carbon material for supercapacitors according to claim 7, characterized in that the sub-step E1 is carried out for at least one hour, the sub-step E2 is carried out for at least one hour, and in the sub-step E2, the acidulant in the first acidic aqueous solution is selected from the group consisting of sulfuric acid, nitric acid, hydrochloric acid and combinations thereof.

9. The method for producing an activated carbon material for a supercapacitor according to claim 1, characterized in that in step G, the material is heated in a nitrogen atmosphere at a heating rate of 1°C / min to 10°C / min to a temperature of less than 1000°C.

10. The method for producing an activated carbon material for a supercapacitor according to claim 1, characterized in that, in step G, the activated carbon material for a supercapacitor has a plurality of micropores and a plurality of mesopores having a pore diameter larger than the micropores, and the ratio of the total volume of the micropores to the total volume of the mesopores is in the range of 1.5 to 5.

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