Classifications

• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
  • Y02E60/10—Energy storage using batteries

Definitions

• the present invention relates to a conductive dispersion and a method for producing the same.
• Patent Document 1 proposes "a carbon nanotube dispersion containing carbon nanotubes, carboxymethylcellulose or its salt, and water, in which the carboxymethylcellulose or its salt has a weight average molecular weight of 10,000 to 100,000 and a degree of etherification of 0.5 to 0.9, and the product (X x Y) of the complex elastic modulus X (Pa) and the phase angle Y (°) of the carbon nanotube dispersion is 100 or more and 1,500 or less.”
• Patent Document 2 proposes a conductive paste composition for secondary battery electrodes, which includes "a fibrous carbon nanomaterial, a binder, and a solvent, the binder containing a first copolymer having an alkylene structural unit and a nitrile group-containing monomer unit and a weight average molecular weight of 170,000 or more and less than 1,500,000," and further includes "a second copolymer containing an alkylene structural unit and a nitrile group-containing monomer unit and a weight average molecular weight of 10,000 or more and less than 170,000.”
• Conductive dispersions require high dispersibility of the conductive carbon material and high stability to maintain the dispersed state without settling for long periods of time.
• Patent Document 1 uses a specific carboxymethylcellulose or its salt alone. In that case, the control of dispersibility and stability by the physical properties of the carboxymethylcellulose or its salt usually results in a trade-off relationship in which improving one reduces the other.
• the copolymer containing the alkylene structural unit and the nitrile group-containing monomer unit of Patent Document 2 is particulate and does not dissolve in the solvent, so the fibrous carbon nanomaterial is prone to settling, making it difficult to improve stability.
• One aspect of the present disclosure relates to a conductive dispersion comprising a conductive carbon material, a liquid component, and a resin component dissolved in the liquid component, the conductive carbon material being dispersed in the liquid component, the conductive carbon material being fibrous or aggregate-like, the resin component comprising a first component and a second component, and the weight-average molecular weight Mw1 of the first component and the weight-average molecular weight Mw2 of the second component satisfying Mw1 ⁇ Mw2.
• a conductive dispersion comprising a conductive carbon material, a liquid component, and a resin component dissolved in the liquid component, the conductive carbon material being dispersed in the liquid component, the conductive carbon material being fibrous or aggregate-like, the resin component comprising a first component and a second component, and a viscosity V1 of a first solution obtained by dissolving the first component in the liquid component at a predetermined concentration, and a viscosity V2 of a second solution obtained by dissolving the second component in the liquid component at the predetermined concentration, satisfying V1 ⁇ V2.
• Another aspect of the present disclosure relates to a method for producing a conductive dispersion comprising a conductive carbon material, a liquid component, and a resin component dissolved in the liquid component, the resin component comprising a first component and a second component, the conductive carbon material being fibrous or aggregate-like, the weight average molecular weight Mw1 of the first component and the weight average molecular weight Mw2 of the second component satisfying Mw1 ⁇ Mw2, (i) dispersing the conductive carbon material and a portion of the resin component in the liquid component to obtain an intermediate dispersion, and (ii) dispersing the remainder of the resin component in the intermediate dispersion, the portion of the resin component used in step (i) containing more of the first component than the second component, and the remainder of the resin component used in step (ii) containing more of the second component than the first component.
• Another aspect of the present disclosure relates to a method for producing a conductive dispersion comprising a conductive carbon material, a liquid component, and a resin component dissolved in the liquid component, the resin component comprising a first component and a second component, the conductive carbon material being fibrous or aggregate-like, a viscosity V1 of a first solution in which the first component is dissolved in the liquid component at a predetermined concentration, and a viscosity V2 of a second solution in which the second component is dissolved in the liquid component at the predetermined concentration satisfy V1 ⁇ V2, and the method includes (i) a step of dispersing the conductive carbon material and a part of the resin component in the liquid component to obtain an intermediate dispersion, and (ii) a step of dispersing the remainder of the resin component in the intermediate dispersion, the part of the resin component used in step (i) containing more of the first component than the second component, and the remainder of the resin component used in step (ii) containing more of the second component
• the conductive dispersion according to the present disclosure (hereinafter also referred to as “dispersion (D)”) contains a conductive carbon material, a liquid component, and a resin component dissolved in the liquid component, and has fluidity.
• Dispersion (D) is a material used in the manufacture of electrodes for electrochemical devices.
• the type of electrode is not limited, and includes electrodes that exhibit capacitance through a faradaic reaction, electrodes that exhibit capacitance through a non-faradaic reaction, and electrodes that have both of these properties.
• the electrochemical device may be a capacitor or a secondary battery.
• the capacitor may be a lithium ion capacitor, an electric double layer capacitor, or the like.
• the secondary battery may be a non-aqueous electrolyte secondary battery, such as a lithium ion secondary battery, a lithium secondary battery (lithium metal secondary battery), or an all-solid-state secondary battery.
• the dispersion (D) is mixed with, for example, an electrode material of the non-aqueous electrolyte secondary battery. In that case, the dispersion (D) constitutes a part of the electrode material of the non-aqueous electrolyte secondary battery.
• the positive electrode of a non-aqueous electrolyte secondary battery is mainly composed of a ceramic material, the use of a conductive carbon material is often essential.
• the conductive carbon material is dispersed in a liquid component.
• the liquid component may be any component capable of dissolving the resin component and dispersing the conductive carbon material.
• the conductive carbon material is in the form of fibers or aggregates.
• One type of conductive carbon material may be used alone, or multiple types may be used in combination.
• Typical examples of fibrous conductive carbon materials are carbon nanotubes (CNTs) and carbon nanofibers (CNFs).
• CNTs may be single-wall carbon nanotubes (SWCNTs), double-wall carbon nanotubes (DWCNTs), multi-wall carbon nanotubes (MWCNTs), or a mixture of both.
• MWCNTs are a general term for carbon nanotubes with two or more walls. Examples of MWCNTs include DWCNTs, triple-wall CNTs, and CNTs with four or more walls.
• a conductive dispersion that contains SWCNT as a conductive carbon material and is capable of achieving both high dispersibility and stability.
• 50 mass% or more of the conductive carbon material in the dispersion (D) may be SWCNT.
• the average diameter of the CNTs is not particularly limited and may be in the range of 1 nm to 50 nm.
• Carbon nanotubes with an average diameter of 5 nm or less contain many SWCNTs.
• N carbon nanotubes e.g., 100 ⁇ N
• 80% or more (0.8N) of these carbon nanotubes may have individual diameters of 5 nm or less, or 3 nm or less.
• CNTs with a diameter of 3 nm or less may be considered SWCNTs.
• the average length of the CNTs is not particularly limited, but may be 0.5 ⁇ m or more, or may be 1 ⁇ m or more and 25 ⁇ m or less.
• N carbon nanotubes e.g., 100 ⁇ N
• the individual lengths of 50% or more (0.5N), and even 80% or more (0.8N) of the carbon nanotubes may be 1 ⁇ m or more, 1 ⁇ m or more and 25 ⁇ m or less, or 1 ⁇ m or more and 20 ⁇ m or less.
• CNFs for example, are a type of MWCNT and are produced as vapor-grown carbon fibers (VGCF). CNFs are typically larger in diameter than CNTs and have at least a partially graphitic structure.
• VGCF vapor-grown carbon fibers
• the average diameter of the CNFs is, for example, 10 nm to 1000 nm, preferably 100 nm to 200 nm.
• the average length of the CNFs is, for example, 5 ⁇ m to 500 ⁇ m, preferably 50 ⁇ m to 100 ⁇ m.
• the average diameter and length of CNTs and CNFs can be determined by image analysis using a scanning electron microscope (SEM).
• SEM scanning electron microscope
• the length can be determined by measuring the length and diameter of several randomly selected CNTs or CNFs (e.g., 100 to 1000), and averaging these.
• Aggregate-like conductive carbon materials are aggregates of minute carbon particles, and may be amorphous carbon having a structure.
• a typical example of an aggregate-like conductive carbon material is carbon black.
• Carbon black has a structure in which carbon particles with a primary particle diameter of, for example, 5 nm to 500 nm are linked in a chain shape.
• Carbon black may be acetylene black, ketjen black, channel black, furnace black, lamp black, thermal black, etc.
• the resin component includes a first component and a second component.
• the resin component acts as a dispersant for dispersing the conductive carbon material in the liquid component, and also has the effect of increasing the viscosity of the dispersion (D). By increasing the viscosity of the dispersion (D), aggregation and sedimentation of the conductive carbon material are suppressed.
• the resin component satisfies at least one of the following conditions (A) and (B). As long as at least one of conditions (A) and (B) is satisfied, the first component and the second component may be the same type of resin or different types of resin.
• a viscosity V1 of a first solution in which a first component is dissolved in a liquid component at a predetermined concentration and a viscosity V2 of a second solution in which a second component is dissolved in a liquid component at the same predetermined concentration satisfy V1 ⁇ V2.
• the weight average molecular weight of the first component and the second component may satisfy 5 ⁇ Mw2/Mw1, 7 ⁇ Mw2/Mw1, 20 ⁇ Mw2/Mw1, or 30 ⁇ Mw2/Mw1.
• the weight-average molecular weight Mw1 of the first component is preferably, for example, 20,000 to 2,000,000.
• a sufficiently small Mw1 increases the dispersibility of the first component itself in the liquid component, and increases the number of molecules of the first component that adsorb to the conductive carbon material, thereby improving the dispersibility of the conductive carbon material.
• the weight-average molecular weight Mw2 of the second component is preferably, for example, 50,000 to 10,000,000.
• Mw2 is sufficiently large, the floating state of the second component itself in the liquid component is stabilized, and the viscosity of the dispersion (D) is increased. This suppresses aggregation and sedimentation of the conductive carbon material, and increases the stability of the dispersion (D).
• the viscosity of the dispersion (D) is excessively increased, it becomes less easy to handle, so it is preferable to set the weight-average molecular weight Mw2 of the second component to the above upper limit or less.
• the viscosity V1 of a first solution in which a first component is dissolved in a liquid component at a predetermined concentration (e.g., 1% by mass), and the viscosity V2 of a second solution in which a second component is dissolved in a liquid component at the same concentration, may satisfy 5 ⁇ V2/V1, 7 ⁇ V2/V1, 100 ⁇ V2/V1, or 500 ⁇ V2/V1.
• the viscosities V1 and V2 may be at the same temperature, and may be measured at, for example, 25°C.
• the viscosity may be measured with a B-type viscometer at a rotation speed of 20 rpm.
• the viscosity V1 (1%/25°C) of a solution of the liquid component with a content of the first component of 1% by mass at 25°C is preferably, for example, 1 to 2000 mPa ⁇ s.
• a sufficiently small viscosity V1 (1%/25°C) increases the dispersibility of the first component itself in the liquid component, and increases the number of molecules of the first component adsorbed to the conductive carbon material, thereby increasing the dispersibility of the conductive carbon material.
• the viscosity V1 (1%/25°C) to be equal to or greater than the above lower limit.
• the viscosity V2 (1%/25°C) of a solution of the liquid component with a content of the second component of 1% by mass at 25°C is preferably, for example, 2 to 50,000 m ⁇ Pa.
• a sufficiently large viscosity V2 (1%/25°C) stabilizes the floating state of the second component itself in the liquid component and increases the viscosity of the dispersion (D). This suppresses aggregation and sedimentation of the conductive carbon material, and increases the stability of the dispersion (D).
• the viscosity of the dispersion (D) is excessively increased, it becomes less easy to handle, so it is preferable to set the viscosity V2 (1%/25°C) to the above upper limit or less.
• the liquid component may be a dispersion medium for dispersing the electrode material in the manufacture of the electrode.
• a liquid component may be a polar solvent.
• the polar solvent may be, for example, water, N-methyl-2-pyrrolidone (NMP), cyclohexanone, alcohol, ether, etc. Among these, water or NMP is preferred.
• 80% by mass or more of the liquid component may be a polar solvent.
• 80% by mass or more of the liquid component may be water.
• 80% by mass or more of the liquid component may be NMP.
• both the first component and the second component are water-soluble polymers.
• the polar solvent is a good solvent for the water-soluble polymer.
• the water-soluble polymer may be a water-soluble polymer compound having a hydrophilic group in the main chain or side chain.
• the hydrophilic group of the water-soluble polymer may be a polyoxyalkylene chain, a hydroxyl group, a carboxyl group, an acid anhydride group, an amino group, a C2-3 alkylene oxide group, or the like.
• water-soluble polymers include polyalkylene glycol compounds, water-soluble polyamides, water-soluble polyimides, water-soluble acrylic resins (such as polyacrylic acid), polyvinyl alcohol, polyvinylpyrrolidone, and cellulose derivatives.
• cellulose derivatives are preferred because they are inexpensive and easily soluble in water and NMP.
• examples of cellulose derivatives include methyl cellulose, carboxymethyl cellulose (CMC), ammonium salts of CMC, and alkali metal salts of CMC.
• the alkali metal salts may be sodium salts, potassium salts, lithium salts, etc.
• the conductive carbon material and the resin component form agglomerated particles, and the agglomerated particles may be dispersed in the liquid component.
• the agglomerated particles may be formed by entangling the conductive carbon material and the resin component with each other.
• the average particle size of the agglomerated particles in the liquid component is preferably, for example, 0.1 ⁇ m or more and 50 ⁇ m or less.
• the average particle size of the agglomerated particles may be measured by a particle size measuring device using dynamic light scattering.
• the average particle size of the agglomerated particles is the median diameter in the volume particle size distribution measured by dynamic light scattering.
• the mass content Mp1 of the first component contained in the agglomerated particles and the mass content Mp2 of the second component contained in the agglomerated particles preferably satisfy Mp1>Mp2.
• the Mp1/Mp2 ratio preferably satisfies 1.1 ⁇ Mp1/Mp2, may satisfy 1.2 ⁇ Mp1/Mp2, or may satisfy 1.5 ⁇ Mp1/Mp2.
• the mass content Mp1 of the first component and the mass content Mp2 of the second component contained in the agglomerated particles can be calculated by separating the agglomerated particles from the dispersion (D), isolating the resin component from the separated agglomerated particles by centrifugation, and analyzing the resin component. Since the resin component contains the first component and the second component, two main peaks are observed when the molecular weight distribution of the resin component is measured by gel permeation chromatography. If the two main peaks partially overlap, the two peaks are separated by waveform separation. The Mp1/Mp2 ratio can be calculated from the integral value of the areas of the two peaks. If three or more peaks are observed in the molecular weight distribution, the peak with the largest area and the peak with the second largest area are regarded as one of the first component and the second component, and the other.
• the mass content Ms1 of the first component and the mass content Ms2 of the second component contained in the liquid component excluding the aggregated particles may satisfy Ms1 ⁇ Ms2.
• the stability of the dispersion (D) is further improved by including a larger amount of the second component, which has a large effect of increasing the stability of the dispersion (D), in the liquid component than the first component.
• the Ms2/Ms1 ratio preferably satisfies 1.1 ⁇ Ms2/Ms1, may satisfy 1.2 ⁇ Ms2/Ms1, or may satisfy 1.5 ⁇ Ms2/Ms1.
• the amount of the resin component per 100 parts by mass of the conductive carbon material contained in the dispersion (D) is preferably, for example, 10 parts by mass or more and 1000 parts by mass or less.
• the amount of the resin component per 100 parts by mass of CNT is preferably, for example, 50 to 1000 parts by mass.
• the amount of the resin component per 100 parts by mass of carbon black is preferably, for example, 10 to 500 parts by mass.
• the greater the amount of resin component within the above range the more the first component can be adsorbed onto the conductive carbon material, and the dispersibility of the conductive carbon material can be increased, while the stability of the dispersion (D) due to the action of the second component is also improved. Furthermore, by setting the amount of resin component to be equal to or less than the upper limit of the above range, it becomes easy to increase the content of the conductive carbon material in the electrode while limiting the content of the resin component in the electrode. This increases the degree of freedom in the amount of dispersion (D) to be blended with respect to the electrode material.
• the amount of resin component per 100 parts by mass of conductive carbon material can be calculated by separating the agglomerated particles from the dispersion (D), separating the resin component and conductive carbon material from the separated agglomerated particles by a method such as centrifugation, and further separating the resin component from the residual liquid after separating the agglomerated particles by removing the liquid component by drying or the like, and then adding up the resin component separated from the agglomerated particles and the resin component separated from the residual liquid.
• the content C1 of the first component and the content C2 of the second component in the dispersion (D) can be calculated. Since the resin components contain the first and second components, two main peaks are observed when the molecular weight distribution of the resin components is measured. If the two main peaks partially overlap, the two peaks are separated by waveform separation. From the integral value of the areas of the two peaks and a calibration curve created in advance, C1, C2, and the C1/C2 ratio can be calculated. If three or more peaks are observed in the molecular weight distribution, the peak with the largest area and the peak with the second largest area are considered to be one of the first and second components, and the other.
• the content C1 of the first component is preferably, for example, 0.2 mass% or more and 5 mass% or less.
• the greater the amount of the first component within the above range the more the first component can be adsorbed by the conductive carbon material, and the greater the dispersibility of the conductive carbon material can be.
• the amount of the first component is set to be equal to or less than the upper limit of the above range, it becomes easy to increase the content of the conductive carbon material in the electrode while limiting the content of the first component in the electrode.
• the content C2 of the second component is, for example, 0.05% by mass or more and preferably 10% by mass or less. The greater the amount of the second component within the above range, the more the stability of the dispersion (D) can be improved.
• the C1/C2 ratio is, for example, 40 or less, and preferably 1 or more.
• C1/C2 ⁇ Mp1/Mp2 it is preferable to satisfy C1/C2 ⁇ Mp1/Mp2.
• C1/C2>Ms1/Ms2 is also satisfied at the same time. It is also possible to satisfy 1.1 ⁇ (Mp1/Mp2)/(C1/C2), or 1.1 ⁇ (Mp1/Mp2)/(C1/C2). It is also possible to satisfy 1.1 ⁇ (C1/C2)/(Ms1/Ms2), or 1.1 ⁇ (C1/C2)/(Ms1/Ms2).
• the viscosity Vd (25°C) of the dispersion (D) at 25°C is preferably, for example, 100 to 10,000 mPa ⁇ s.
• the stability of the dispersion (D) is high, and when it is blended with the electrode material, it is easy to highly disperse it in the electrode material.
• the method for producing the dispersion (D) includes (i) a step of dispersing a conductive carbon material and a part of the resin component in a liquid component to obtain an intermediate dispersion, and (ii) a step of dispersing at least a part of the remaining resin component in the intermediate dispersion.
• the entire amount of the part of the resin component may be dispersed in the liquid component at once, or may be dispersed in a plurality of times.
• the entire amount of the remaining resin component may be dispersed in the intermediate dispersion at once, or may be dispersed in a plurality of times.
• the entire amount of the liquid component may be mixed with the conductive carbon material in the step (i), or the liquid component may be mixed separately in the steps (i) and (ii).
• a portion of the resin component used in step (i) contains more of the first component than the second component.
• Step (i) is mainly a step for adsorbing the first component to the conductive carbon material.
• 90% by mass or more of the portion of the resin component used in step (i) may be the first component. That is, the amount of the first component used relative to the total amount of the first and second components used in step (i) may be 90% by mass or more, 95% by mass or more, or even 100%.
• the entire amount of the liquid component may be mixed with the conductive carbon material in step (i), or the liquid component may be mixed separately in steps (i) and (ii).
• Step (ii) is a step of dissolving the second component in an intermediate dispersion to obtain a dispersion (D) having a higher viscosity and suppressed fluidity than the intermediate dispersion.
• a dispersion (D) having a higher viscosity and suppressed fluidity than the intermediate dispersion.
• 90% by mass or more of the remainder of the resin component used in step (ii) may be the second component.
• the amount of the second component used relative to the total amount of the first component and the second component used in step (ii) may be 90% by mass or more, 95% by mass or more, or 100%.
• (Technique 2) A conductive carbon material, a liquid component, and a resin component dissolved in the liquid component; Including, the conductive carbon material is dispersed in the liquid component; the conductive carbon material is in a fibrous or aggregate form;
• the resin component includes a first component and a second component, A conductive dispersion, in which the viscosity V1 of a first solution obtained by dissolving the first component in the liquid component at a predetermined concentration and the viscosity V2 of a second solution obtained by dissolving the second component in the liquid component at the predetermined concentration satisfy V1 ⁇ V2.
• (Technique 3) The conductive dispersion according to claim 1, wherein Mw2/Mw1 satisfies 5 ⁇ Mw2/Mw1.
• the conductive dispersion according to technique 2 wherein V2/V1 satisfies 5 ⁇ V2/V1.
• the liquid component comprises a polar solvent
• the conductive dispersion according to any one of techniques 1 to 4 wherein the first component and the second component are both water-soluble polymers.
• the conductive dispersion according to technology 5 wherein the water-soluble polymer is a cellulose derivative.
• a method for producing a conductive dispersion comprising: a conductive carbon material; a liquid component; and a resin component dissolved in the liquid component, the method comprising the steps of:
• the resin component includes a first component and a second component, the conductive carbon material is in a fibrous or aggregate form;
• the weight average molecular weight Mw1 of the first component and the weight average molecular weight Mw2 of the second component satisfy Mw1 ⁇ Mw2, (i) dispersing the conductive carbon material and a portion of the resin component in the liquid component to obtain an intermediate dispersion; (ii) dispersing the remainder of the resin component in the intermediate dispersion; having A portion of the resin component used in step (i) contains the first component in a larger amount than the second component, A method for producing a conductive dispersion, wherein at least a portion of the remainder of the resin component used in step (ii) contains the second component in a larger amount than the first component.
• a method for producing a conductive dispersion comprising: a conductive carbon material; a liquid component; and a resin component dissolved in the liquid component, the method comprising the steps of:
• the resin component includes a first component and a second component, the conductive carbon material is in a fibrous or aggregate form; a viscosity V1 of a first solution obtained by dissolving the first component in the liquid component at a predetermined concentration, and a viscosity V2 of a second solution obtained by dissolving the second component in the liquid component at the predetermined concentration satisfy V1 ⁇ V2;
• (ii) dispersing the remainder of the resin component in the intermediate dispersion having A portion of the resin component used in step (i) contains the first component in a larger amount than the second component,
• Example The conductive dispersion according to the present disclosure will be described in more detail below with reference to examples and comparative examples, although the present disclosure is not limited to the following examples.
• Example 1 Step (i) 100 parts by mass of CNT, which is a conductive carbon material, 100 parts by mass of the first CMC (Na salt of CMC), which is the first component of the resin component, and 9,800 parts by mass of water, which is a liquid component, were mixed and subjected to a dispersion process 10 times using a high-pressure homogenizer to obtain an intermediate dispersion.
• CNT which is a conductive carbon material
• first CMC Na salt of CMC
• water which is a liquid component
• the weight average molecular weight Mw1 of the first CMC measured by gel permeation chromatography (GPC method) was 70,000, and the viscosity V1 of the first solution containing 1% by mass of the first CMC was 2 mPa ⁇ s at 25°C.
• the CNTs had an average diameter of 1.4 nm and an average length of 1 ⁇ m, and were essentially all SWCNTs.
• Step (ii) 100 parts by mass of the second CMC (Na salt of CMC) was added to the intermediate dispersion, and water was added as needed to adjust the CNT concentration, thereby obtaining a dispersion (D1).
• the second CMC Na salt of CMC
• the amount of resin component (total amount of first CMC and second CMC) per 100 parts by mass of CNT was 200 parts by mass
• the CNT content in dispersion (D) was 1.0% by mass
• the first CMC content C1 was 1.0% by mass
• the second CMC content C2 was 1.0% by mass
• the C1/C2 ratio was 1.
• Sedimentation resistance (%) 100 x (solid content of supernatant) / solid content of dispersion (D)
• Viscosity of Dispersion (D) The viscosity of the dispersion (D1) at 25° C. was measured using a Brookfield viscometer at a rotation speed of 20 rpm and was found to be 500 mPa/s.
• the average particle size of the aggregated particles contained in the obtained dispersion (D1) was measured using a laser diffraction scattering type particle size measuring device (MT3000 II manufactured by Microtrac Corporation). As a result, the median diameter in the volume particle size distribution was 10 ⁇ m, and it was confirmed that the aggregated particles were small and had high dispersibility.
• Comparative Example 1 100 parts by mass of CNT, which is a conductive carbon material, 100 parts by mass of the first CMC, which is the first component of the resin component, and 9800 parts by mass of a liquid component were mixed, and the dispersion process was performed 10 times with a high-pressure homogenizer to obtain a dispersion (CD1).
• CD1 dispersion
• the average particle size of the aggregated particles contained in the obtained dispersion (CD1) was measured in the same manner as in Example 1, the median diameter in the volume particle size distribution was 10 ⁇ m, and it was confirmed that the aggregated particles were small and had high dispersibility.
• the stability of the dispersion (CD1) was evaluated, the sedimentation resistance was 69%, and the stability was insufficient.
• the viscosity of the dispersion (CD1) was 100 mPa/s.
• Comparative Example 2 A dispersion (CD2) was obtained in the same manner as in Comparative Example 1, except that the weight-average molecular weight of the first CMC was changed to 200,000.
• the average particle size of the aggregated particles contained in the obtained dispersion (CD2) was measured in the same manner as in Example 1, and the median diameter in the volumetric particle size distribution was 15 ⁇ m, and it was confirmed that the aggregated particles were small and had high dispersibility.
• the stability of the dispersion (CD2) was evaluated, the sedimentation resistance was 68%, and the stability was insufficient.
• the viscosity of the dispersion (CD1) was 300 mPa/s.
• Comparative Example 3 A dispersion (CD3) was obtained in the same manner as in Comparative Example 1, except that the weight-average molecular weight of the first CMC was changed to 3,000,000.
• the average particle size of the aggregated particles contained in the obtained dispersion (CD3) was measured in the same manner as in Example 1, and the median diameter in the volumetric particle size distribution was 30 ⁇ m, and it was confirmed that the aggregated particles were large and had low dispersibility.
• the stability of the dispersion (CD3) was evaluated, the sedimentation resistance was 66%, and the stability was also insufficient.
• the viscosity of the dispersion (CD1) was 500 mPa/s.
• Example 2 to 10 and Comparative Examples 4 to 5 Each dispersion (D2 to D10, CD4, and CD5) was prepared in the same manner as in Example 1, except that the weight average molecular weight and the amount of the first CMC and the second CMC used were changed as shown in Table 1, and the stability (resistance to sedimentation) and viscosity were measured. The results are shown in Table 1.
• the weight-average molecular weight of the first CMC used during the dispersion process of the CNTs was different.
• the weight-average molecular weight was small, the number of molecules that could be adsorbed to the CNTs was large, which made dispersion easier and resulted in small CNT agglomerated particles after dispersion process.
• the viscosity of the dispersion (CD) was low, so the sedimentation resistance was low.
• a first CMC with a large weight-average molecular weight was used, the viscosity of the dispersion (CD) was high, but the size of the CNT agglomerated particles was large, so the sedimentation resistance was low.
• the conductive dispersion according to the present disclosure can be used to improve the conductivity of electrodes (particularly positive electrodes) of electrochemical devices (particularly lithium secondary batteries).

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