Liquid composition for electrode-integrated separator, method for producing particle layer, method for producing electrode, and method for producing electrochemical device

Abstract

To provide a liquid composition capable of improving electrical insulation resistance of an electrode-integrated separator and suppressing generation of a coffee ring.SOLUTION: Liquid composition contains particles, resin, solvent A and solvent B different from the solvent A. The liquid composition has a surface tension against air of 25 mN / m or more and less than 50 mN / m at 25°C. The liquid composition has a 90% diameter of 2.5 μm or less. In addition, the liquid composition has a median size of 1 μm or less.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to For electrode integrated separators The present invention relates to a liquid composition, a method for producing a particle layer, a method for producing an electrode, and a method for producing an electrochemical device. [Background technology]

[0002] 2. Description of the Related Art Conventionally, in electrochemical elements such as lithium ion secondary batteries, electric double layer capacitors, lithium ion capacitors, and redox capacitors, paper, nonwoven fabrics, and porous films have been used as separators for the purpose of preventing short circuits between the positive and negative electrodes.

[0003] In recent years, an electrode-integrated separator in which an electrode mixture layer and a particle layer are formed in this order on an electrode substrate has been used (see, for example, Patent Documents 1 and 2).

[0004] An electrode-integrated separator is generally produced by applying a liquid composition containing particles onto an electrode mixture layer. Summary of the Invention [Problem to be solved by the invention]

[0005] However, since the electrode mixture layer is an absorbent medium having a porous structure, when a liquid composition is applied onto the electrode mixture layer, the liquid composition is absorbed into the electrode mixture layer, and the particles contained in the liquid composition penetrate into the electrode mixture layer, resulting in a decrease in the thickness of the particle layer. This reduces the electrical insulation resistance between the electrode substrate and the particle layer, i.e., the electrical insulation resistance of the electrode-integrated separator.

[0006] On the other hand, by increasing the contact angle of the liquid composition with the electrode mixture layer, the penetration of particles into the electrode mixture layer is suppressed, and the resistance of the electrode-integrated separator increases; however, in this case, coffee ring occurs, resulting in greater unevenness in the resistance of the electrode-integrated separator.

[0007] An object of one aspect of the present invention is to provide a liquid composition that can improve the electrical insulation resistance of an electrode-integrated separator and also suppress the occurrence of coffee ring. [Means for solving the problem]

[0008] One aspect of the present invention is a liquid composition containing particles, a resin, a solvent A, and a solvent B different from solvent A, wherein the surface tension against air at 25°C is 25 mN / m or more and less than 50 mN / m, the 90% diameter is 2.5 μm or less, and the median diameter is 1 μm or less.

[0009] Another aspect of the present invention is a liquid composition containing particles, a resin, a solvent A, and a solvent B different from the solvent A, the liquid composition having a median diameter of D 50A+B [μm], 90% diameter is D 90A+B [μm], the median diameter of the dispersion liquid obtained by removing the solvent B from the ink is D 50A [μm], the median diameter of the dispersion liquid obtained by removing the solvent A from the ink is D 50B [μm], the formula 1 <D 50B / D 50A 1 <D 50A+B / D 50A <1.1 D 90A+B <5 Meet the following.

[0010] Another aspect of the present invention is a liquid composition produced by adding a solvent B different from solvent A to a dispersion containing particles, a resin, and solvent A, wherein the surface tension against air at 25°C is 25 mN / m or more and less than 50 mN / m, the 90% diameter is 2.5 μm or less, and the median diameter of the dispersion is 1 μm or less. Effect of the Invention

[0011] According to one aspect of the present invention, it is possible to provide a liquid composition that can improve the electrical insulation resistance of an electrode-integrated separator and also suppress the occurrence of coffee ring. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a schematic perspective view showing an example of a liquid ejection device. [Diagram 2] FIG. 2 is a schematic cross-sectional view showing an example of a separator-integrated electrode. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, an embodiment of the present invention will be described.

[0014] [Properties of liquid composition 1] The liquid composition of the present embodiment contains particles, a resin, a solvent A, and a solvent B that is different from solvent A.

[0015] Solvent A is a solvent that has the function of dispersing particles in the liquid composition.

[0016] Solvent B is a solvent intended to compensate for the lack of functionality in solvent A.

[0017] Examples of solvent B include, in addition to solvents that have the function of dispersing particles, solvents with high boiling points intended to prevent the nozzle of the liquid ejection head from drying out, solvents intended to adjust the viscosity and surface tension to an appropriate level for ejection from the liquid ejection head, and solvents intended to suppress absorption of particles into the electrode composite layer.

[0018] The liquid composition of the present embodiment preferably has a surface tension with respect to air of 25 mN / m or more and less than 50 mN / m at 25° C. If the surface tension with respect to air at 25° C. of the liquid composition is less than 25 mN / m, the resistance of the electrode-integrated separator will be low, and if it is 50 mN / m or more, coffee ring will occur.

[0019] The 90% diameter of the liquid composition of this embodiment is 2.5 μm or less, and preferably 2.0 μm or less. If the 90% diameter of the liquid composition exceeds 2.5 μm, the dispersibility of the liquid composition decreases.

[0020] The liquid composition of the present embodiment has a median diameter of 1 μm or less, and preferably 0.8 μm or less. If the median diameter of the liquid composition exceeds 1 μm, the Brownian motion of the particles becomes small, and the dispersion stability of the liquid composition decreases.

[0021] In this specification and claims, the 90% diameter and the median diameter refer to the minimum value of the 90% cumulative particle diameter on a volume basis (minimum 90% diameter) and the minimum value of the 50% cumulative particle diameter on a volume basis (minimum median diameter), respectively, measured by a laser diffraction method.

[0022] Here, the 90% diameter is used as an index of the presence or absence of coarse particles due to poor dispersion or re-aggregation due to excessive dispersion, that is, as an index of dispersibility.

[0023] On the other hand, the median size is used as an index of dispersion stability because it is sensitive to the minute dispersion environment. That is, if the median size is large, the particles are likely to settle and it is difficult to maintain the dispersion.

[0024] The liquid composition of the present embodiment can be produced by adding solvent B to a dispersion containing particles, a resin, and solvent A.

[0025] The liquid composition of the present embodiment may further contain a surfactant, a pH adjuster, an anti-rust agent, a preservative, an anti-fungal agent, an antioxidant, an anti-reducing agent, an evaporation promoter, a chelating agent, and the like for the purposes of adjusting the viscosity, adjusting the surface tension, controlling the evaporation of the solvent, improving the solubility of the additives, improving the dispersibility of the particles, sterilization, and the like.

[0026] The liquid composition of the present embodiment can be produced using a known dispersing device.

[0027] Specific examples of the dispersing device include a stirrer, a ball mill, a bead mill, a ring mill, a high-pressure dispersing device, a rotary high-speed shearing device, and an ultrasonic dispersing device.

[0028] [particle] The particles may be either organic particles or inorganic particles, but are preferably inorganic particles in terms of heat resistance.

[0029] From the viewpoint of insulating properties, the particles are preferably insulating particles.

[0030] Specific examples of materials constituting inorganic particles include aluminum oxide, silica, calcium carbonate, titanium oxide, calcium phosphate, titanium oxide, silicon oxide, zirconium oxide, etc. Among these, inorganic oxides such as aluminum oxide and silica are preferred when used to manufacture separator-integrated electrodes because of their high insulating and heat resistance. Furthermore, aluminum oxide is even more preferred because it functions as a scavenger for "junk" chemical species, i.e., chemical species that cause capacity fade in lithium-ion secondary batteries. In addition, aluminum oxide has excellent wettability with electrolytes, which increases the electrolyte absorption rate and improves the cycle performance of lithium-ion secondary batteries.

[0031] Specific examples of materials constituting the organic particles include polyvinylidene fluoride (PVDF), polyvinylpyrrolidone (PVP), polyester, polypropylene, polyethylene, chitin, chitosan, cellulose, carboxymethylcellulose (CMC), polystyrene, and melamine resin.

[0032] [resin] The number average molecular weight of the resin is usually 1,000 to 100,000, and from the viewpoint of suppressing an increase in viscosity of the liquid composition, it is preferably 1,000 to 10,000, and more preferably 1,000 to 5,000.

[0033] The resin is preferably a polymer dispersant having a dispersing group and an adsorptive group. In particular, when the particles are charged, a polymer dispersant having an ionic group, as an adsorptive group, of the opposite polarity to the polarity of the charged particles is preferred in terms of the strength of adsorptive strength to the particles.

[0034] Examples of the ionic group include a sulfonic acid group and a salt thereof (e.g., a potassium salt, a sodium salt, a lithium salt, an ammonium salt), a carboxyl group and a salt thereof (e.g., a potassium salt, a sodium salt, a lithium salt, an ammonium salt), a primary, secondary, or tertiary amino group and a salt thereof, and the like.

[0035] The ionic group may be either an anionic group or a cationic group, but is preferably an anionic group from the standpoint of dispersibility of the inorganic particles.

[0036] Examples of the anionic group include salts of a carboxyl group, a sulfonic acid group, and a phosphoric acid group.

[0037] The ionic group is usually present on a side chain or at both ends of the polymer dispersant, but from the viewpoint of suppressing an increase in the viscosity of the liquid composition, it is preferable that the ionic group is present on the side chain of the polymer dispersant.

[0038] The dispersing group may have any structure as long as it has solubility in solvent A and solvent B. When used as a lithium ion secondary battery, an oligoether group is preferred from the viewpoint of ion conductivity.

[0039] The oligoether group is a group in which a hydroxyl group has been removed from the end of an ethylene glycol or propylene glycol polymer.

[0040] The molecular weight of the ethylene glycol or propylene glycol polymer is preferably 100 to 10,000, and more preferably 100 to 5,000. When the molecular weight of the ethylene glycol or propylene glycol polymer is 100 or more, the dispersibility of the particles is improved, and when it is 10,000 or less, an increase in the viscosity of the liquid composition can be suppressed.

[0041] The terminal on the side to which the oligoether group is not bonded may be a hydroxyl group, or a methoxy group, ethoxy group, propoxy group, or the like.

[0042] When a resin having an oligoether group is used, even if solvents A and B have high polarity, the dispersibility of the particles can be improved.

[0043] Commercially available polymer dispersants include, for example, DISPERBYK-103, DISPERBYK-118, DISPERBYK-2155 (all manufactured by Big Chemie), NOPCOSPERSE-092, SN-SPERSE-2190, SN-DISPERSANT-9228 (all manufactured by San Nopco), S-reem AD-3172M, S-reem 2093, Marialim AKM-0513, Marialim HKM-50A, Marialim HKM-150A, Marialim SC-0505K, Marialim SC-1015F, Marialim SC-0708A (all manufactured by NOF Corp.).

[0044] The mass ratio of the polymer dispersant to the particles is usually 0.01% to 10%, but taking into consideration the dispersibility of the particles, it is preferably 0.1% to 10%.

[0045] As the resin, a polymer dispersant and a binder may be used in combination.

[0046] Examples of the binder include polyvinylidene fluoride, styrene butadiene rubber, and acrylic resin.

[0047] The binder may be dissolved or dispersed in the liquid composition.

[0048] Instead of the binder, a precursor of the binder may be used.

[0049] The binder precursor may be, for example, a monomer.

[0050] For example, a liquid composition containing a monomer and, if necessary, further containing a polymerization initiator is applied onto an absorbing medium, and then the liquid composition is heated or irradiated with light, whereby the monomer is polymerized to produce a binder.

[0051] [Solvent A] Solvent A is preferably a lactam, an alcohol, a sulfoxide, an ester or a ketone.

[0052] Specific examples of lactams include 1-methyl-2-pyrrolidone, 2-pyrrolidone, and the like.

[0053] Specific examples of the alcohol include isopropyl alcohol, butanol, and diacetone alcohol.

[0054] Specific examples of sulfoxides include dimethyl sulfoxide.

[0055] Specific examples of the ester include ethyl acetate, butyl acetate, ethyl lactate, and ethylene glycol diacetate.

[0056] Specific examples of ketones include diisobutyl ketone, 2-butanone, 2-pentanone, and diacetone alcohol.

[0057] [Solvent B] Solvent B is preferably an ether, a glycol, an ester, an alcohol or a lactam.

[0058] A specific example of the ether is propylene glycol monopropyl ether.

[0059] Specific examples of glycols include propylene glycol, ethylene glycol, triethylene glycol, and hexylene glycol.

[0060] Specific examples of the ester include ethyl lactate, ethylene carbonate, and ethylene glycol diacetate.

[0061] Specific examples of the alcohol include cyclohexanol and propylene glycol monopropyl ether.

[0062] Specific examples of lactams include 2-pyrrolidone.

[0063] [Properties of liquid composition 2] The liquid composition of the present embodiment contains particles, a resin, a solvent A, and a solvent B different from solvent A.

[0064] The median diameter of the liquid composition of this embodiment is D 50A+B [μm], and the 90% diameter of the liquid composition of this embodiment is D 90A+B [μm], the median diameter of the dispersion liquid excluding the solvent A from the liquid composition of this embodiment is D 50B [μm], the median diameter of the dispersion liquid excluding the solvent B from the liquid composition of this embodiment is D 50A In [μm], formula 1 <D 50B / D 50A 1 <D 50A+B / D 50A <1.1 D 90A+B <5 Meet the following.

[0065] D 50B / D 50A When the ratio is 1 or less, the difference in dispersibility of particles between solvent A and solvent B becomes small, and the particles easily penetrate into the electrode mixture layer.

[0066] D 50A+B / D 50A If it is 1 or less, the difference in particle dispersibility between solvent A and solvent B will be small, and the particles will be more likely to penetrate into the electrode mixture layer. If it is 1.1 or more, the dispersibility of the liquid composition will be poor, the particles will tend to aggregate, and the difference between the nozzle diameter of the liquid ejection head and the particle diameter will be small, making nozzle clogging more likely to occur.

[0067] D 90A+BIf the ratio is 5 or more, the difference between the nozzle diameter of the liquid ejection head and the particle diameter becomes small, and nozzle clogging becomes more likely to occur.

[0068] In this specification and claims, a dispersion obtained by excluding solvent A (solvent B) from a liquid composition means a dispersion in which particles are dispersed in a solution in which solvent B (solvent A) and a resin are present, due to the resin.

[0069] The particles, resin, solvent A, and solvent B are the same as those described in [Properties of Liquid Composition 1].

[0070] The liquid composition of the present embodiment may further contain a surfactant, a pH adjuster, an anti-rust agent, a preservative, an anti-fungal agent, an antioxidant, an anti-reducing agent, an evaporation promoter, a chelating agent, and the like for the purposes of adjusting the viscosity, adjusting the surface tension, controlling the evaporation of the solvent, improving the solubility of the additives, improving the dispersibility of the particles, sterilization, and the like.

[0071] The liquid composition of the present embodiment can be produced using a known dispersing device.

[0072] Specific examples of the dispersing device include a stirrer, a ball mill, a bead mill, a ring mill, a high-pressure dispersing device, a rotary high-speed shearing device, and an ultrasonic dispersing device.

[0073] [Method of applying liquid composition] Specific examples of the method for applying the liquid composition include dip coating, spray coating, spin coating, bar coating, slot die coating, doctor blade coating, offset printing, gravure printing, flexographic printing, letterpress printing, screen printing, liquid ejection, electrophotographic printing using a liquid development system, etc. Among these, the liquid ejection is preferred because it is possible to control the ejection position.

[0074] Examples of the method for ejecting the liquid composition in the liquid ejection method include a method for imparting mechanical energy to the liquid composition, a method for imparting thermal energy to the liquid composition, etc. Among these, the method for imparting mechanical energy to the liquid composition is preferred.

[0075] When using a liquid ejection method, a technology using the liquid ejection principle of a known liquid ejection device may be applied, but it is preferable to use solvents that are resistant to the flow path and nozzle of the liquid ejection head installed in the liquid ejection device as solvents A and B contained in the liquid composition.

[0076] FIG. 1 shows an example of a liquid ejection device.

[0077] In the liquid ejection device 11, a cartridge 20 containing a liquid composition is housed in a carriage 18 inside a main body housing 12. In this state, the liquid composition is supplied from the cartridge 20 to a recording head 18a mounted on the carriage 18. The recording head 18a is capable of ejecting the liquid composition.

[0078] The recording head 18a mounted on the carriage 18 is guided by guide shafts 21 and 22 and moves via a timing belt 23 driven by a main scanning motor 24. Meanwhile, the absorption medium is positioned opposite the recording head 18a by a platen 19. In the drawing, 16 denotes a gear mechanism, 17 denotes a sub-scanning motor, and 26 denotes a main scanning motor.

[0079] [Method of using the liquid composition] A method of using the liquid composition involves applying the liquid composition onto an absorbent medium.

[0080] The absorbent medium means a medium capable of absorbing a liquid composition.

[0081] Exemplary absorbent media include, for example, porous membranes.

[0082] When an electrode substrate on which an electrode mixture layer containing an active material is formed is used as the porous membrane, an electrode integrated separator can be produced.

[0083] Examples of the negative electrode active material include metallic lithium, lithium alloys, carbon materials capable of absorbing or releasing lithium ions, such as carbon and graphite, and conductive polymers doped with lithium ions.

[0084] The positive electrode active material is, for example, a compound represented by the general formula (CF x ) n Examples of the metal oxides include graphite fluoride represented by the formula (I), metal oxides such as CoLiO2, MnO2, V2O5, CuO, Ag2CrO4, and TiO2, and metal sulfides such as CuS.

[0085] The electrode substrate may be, for example, a copper foil or an aluminum foil.

[0086] Examples of absorbing media other than those mentioned above include undercoats used in reflective display elements and electrode layers used in printed electronics.

[0087] [Separator integrated electrode] The separator-integrated electrode refers to an electrode in which an electrode mixture layer and a particle layer are formed in this order on an electrode substrate.

[0088] An example of a separator-integrated electrode is shown in Fig. 2. Fig. 2(a) and (b) are a cross-sectional view and a top view, respectively.

[0089] The separator-integrated electrode 30 has an electrode mixture layer 32 and a particle layer 33 formed in this order on an electrode substrate 31, and the liquid composition of this embodiment is used to form the particle layer 33.

[0090] Use of the separator-integrated electrode 30 eliminates the need for the process of separately unwinding and winding or stacking the electrode and separator when manufacturing an electrochemical element, and is therefore expected to dramatically improve the manufacturing efficiency of the electrochemical element.

[0091] Examples of electrochemical elements include lithium ion secondary batteries, magnesium ion secondary batteries, magnesium secondary batteries, sodium ion secondary batteries, and sodium secondary batteries.

[0092] The electrochemical device can be applied to, for example, vehicles equipped with on-board batteries, smartphones, and the like. EXAMPLES

[0093] Examples of the present invention will be described below, but the present invention is not limited to these examples. In addition, "parts" and "%" are based on mass unless otherwise specified.

[0094] [Method of thoroughly dispersing particles in a solvent using resin] A predetermined amount of particles, solvent, and resin were put into a zirconia container of a cooling nano-pulverizer NP-100 (manufactured by Thinky) as a bead mill dispersion device, and then beads with a particle size of 0.2 mm were appropriately put in and dispersed. At this time, the dispersion time was appropriately selected depending on the combination of particles, solvent, and resin.

[0095] [Particle size distribution of liquid composition or dispersion] The particle size distribution of the liquid composition or dispersion was measured using a laser diffraction particle size distribution analyzer Mastersizer 3000 (manufactured by Malvern Instruments).

[0096] Here, the median diameter and 90% diameter of the dispersion liquid obtained by removing the solvent B from the liquid composition are respectively D 50A , D 90A The median diameter and 90% diameter of the dispersion liquid obtained by removing the solvent A from the liquid composition are defined as D 50B , D 90B The median diameter and 90% diameter of the liquid composition are defined as D 50A+B , D 90A+BLet us assume that.

[0097] When measuring the particle size distribution of a liquid composition or dispersion, if there was a cumulative value of particle sizes of 0.1 μm or less, it was determined that the reliability was low, and the cumulative value of particle sizes of 0.1 μm or less was removed before determining the median diameter and 90% diameter.

[0098] [Surface tension of liquid composition relative to air] The surface tension of the liquid composition against air was measured at 25° C. using a contact angle meter PocketDyne (manufactured by KRuSS).

[0099] [Example 1-1] (Preparation of Dispersion) Ammonium fumarate and 1.5% of HKM-150A (NOF Corp.), a multifunctional comb-shaped functional polymer (resin) having an ionic group in the main chain and a polyoxyalkylene chain in the graft chain, were thoroughly dispersed in 48.5% 1-methyl-2-pyrrolidone (solvent A) with 50% alumina particles AKP3000 (Sumitomo Chemical Co., Ltd.) with a median particle size of 0.8 μm, to obtain a dispersion with a solid content of 50%. The dispersion was D 50A is 1μm or less, and D 90A was less than 2 μm.

[0100] (Preparation of Liquid Composition) A liquid composition with a solid content of 30% was obtained by mixing 60% of the dispersion liquid, 30% of 1-methyl-2-pyrrolidone (solvent A), and 10% of propylene glycol (solvent B). 50A+B is 1μm or less, and D 90A+B was less than 2 μm.

[0101] [Example 1-2] A liquid composition was obtained in the same manner as in Example 1-1, except that in (Preparation of liquid composition), the amounts of 1-methyl-2-pyrrolidone and propylene glycol added were changed to 20% and 20%, respectively (see Table 1).

[0102] [Examples 1-3] A liquid composition was obtained in the same manner as in Example 1-1, except that in (Preparation of liquid composition), the amounts of 1-methyl-2-pyrrolidone and propylene glycol added were changed to 10% and 30%, respectively (see Table 1).

[0103] [Examples 1-4] A liquid composition was obtained in the same manner as in Example 1-1, except that in (Preparation of liquid composition), the amounts of 1-methyl-2-pyrrolidone and propylene glycol added were changed to 0% and 40%, respectively (see Table 1).

[0104] [Examples 2-1 to 2-4] A liquid composition was obtained in the same manner as in Examples 1-1 to 1-4, except that dimethyl sulfoxide was used as the solvent A (see Table 1).

[0105] [Examples 3-1 to 3-4] Inks were obtained in the same manner as in Examples 1-1 to 1-4, except that ethyl lactate was used as the solvent A (see Table 1).

[0106] [Examples 4-1 to 4-4] A liquid composition was obtained in the same manner as in Examples 1-1 to 1-4, except that diisobutyl ketone was used as solvent A, 2-pyrrolidone was used as solvent B, and SC-0708A (manufactured by NOF Corp.), a multifunctional comb-type functional polymer having an ionic group in the main chain and a polyoxyalkylene chain in the graft chain, was used as the resin (see Table 1).

[0107] [Comparative Example 5-1, Examples 5-2 to 5-4] A liquid composition was obtained in the same manner as in Examples 4-1 to 4-4, except that isopropyl alcohol was used as the solvent A (see Table 1).

[0108] [Examples 6-1 to 6-4] A liquid composition was obtained in the same manner as in Examples 1-1 to 1-4, except that ethylene glycol was used as the solvent B (see Table 1).

[0109] [Examples 7-1 to 7-4] A liquid composition was obtained in the same manner as in Examples 2-1 to 2-4, except that ethylene glycol was used as the solvent B (see Table 1).

[0110] [Examples 8-1 to 8-4] A liquid composition was obtained in the same manner as in Examples 3-1 to 3-4, except that ethylene glycol was used as the solvent B (see Table 1).

[0111] [Examples 9-1 to 9-4] Inks were obtained in the same manner as in Examples 4-1 to 4-4, except that ethyl lactate was used as the solvent A (see Table 1).

[0112] [Examples 10-1 to 10-4] A liquid composition was obtained in the same manner as in Examples 4-1 to 4-4, except that diacetone alcohol was used as the solvent A (see Table 2).

[0113] [Examples 11-1 to 11-4] A liquid composition was obtained in the same manner as in Examples 4-1 to 4-4, except that cyclohexanone was used as the solvent A (see Table 2).

[0114] [Comparative Examples 12-1 to 12-4] A liquid composition was obtained in the same manner as in Examples 4-1 to 4-4, except that ethylene glycol was used as the solvent B (see Table 2).

[0115] [Comparative Examples 13-1 to 13-4] A liquid composition was obtained in the same manner as in Examples 4-1 to 4-4, except that propylene glycol was used as the solvent B (see Table 2).

[0116] [Comparative Examples 14-1 to 14-4] A liquid composition was obtained in the same manner as in Examples 10-1 to 10-4, except that ethylene glycol was used as the solvent B (see Table 2).

[0117] [Comparative Examples 15-1 to 15-4] A liquid composition was obtained in the same manner as in Examples 10-1 to 10-4, except that propylene glycol was used as the solvent B (see Table 2).

[0118] [Examples 16-1 to 16-4] A liquid composition was obtained in the same manner as in Examples 4-1 to 4-4, except that 1-methyl-2-pyrrolidone was used as the solvent A (see Table 2).

[0119] [Examples 17-1 to 17-4] A liquid composition was obtained in the same manner as in Examples 4-1 to 4-4, except that dimethyl sulfoxide was used as the solvent A (see Table 2).

[0120] [Examples 18-1 to 18-4] A liquid composition was obtained in the same manner as in Examples 1-1 to 1-4, except that 2-pyrrolidone was used as the solvent B (see Table 2).

[0121] [Examples 19-1 to 19-4] A liquid composition was obtained in the same manner as in Examples 2-1 to 2-4, except that 2-pyrrolidone was used as the solvent B (see Table 3).

[0122] [Examples 20-1 to 20-4] Inks were obtained in the same manner as in Examples 4-1 to 4-4, except that butyl acetate was used as the solvent A (see Table 3).

[0123] [Examples 21-1 to 21-4] Inks were obtained in the same manner as in Examples 4-1 to 4-4, except that 2-butanone was used as the solvent A (see Table 3).

[0124] [Comparative Examples 22-1 to 22-4] A liquid composition was obtained in the same manner as in Examples 6-1 to 6-4, except that water was used as the solvent A and HKM-50A (manufactured by NOF Corp.), a multifunctional comb-type functional polymer having an ionic group in the main chain and a polyoxyalkylene chain in the graft chain, was used as the resin (see Table 3).

[0125] [Comparative Examples 23-1 to 23-4] A liquid composition was obtained in the same manner as in Examples 6-1 to 6-4, except that propylene glycol was used as the solvent B (see Table 3).

[0126] [Example 24-4] A liquid composition was obtained in the same manner as in Comparative Example 22-4, except that 1.4% HKM-50A (manufactured by NOF Corp.) and 0.1% fluorosurfactant F-444 (manufactured by DIC Corp.) were used instead of 1.5% HKM-150A (manufactured by NOF Corp.) (see Table 3).

[0127] [Examples 25-1 to 25-4] A liquid composition was obtained in the same manner as in Examples 9-1 to 9-4, except that cyclohexanol was used as the solvent B (see Table 3).

[0128] [Examples 26-1 to 26-4] Except for using cyclohexanol as the solvent B, liquid compositions were obtained in the same manner as in Examples 10-1 to 10-4 (see Table 3).

[0129] [Examples 27-1 to 27-4] Except for using cyclohexanol as the solvent B, liquid compositions were obtained in the same manner as in Examples 11-1 to 11-4 (see Table 3).

[0130] [Comparative Examples 28-1, 28-2, Examples 28-3, 28-4] A liquid composition was obtained in the same manner as in Comparative Example 5-1 and Examples 5-2 to 5-4, except that cyclohexanol was used as the solvent B (see Table 3).

[0131] [Examples 29-1 to 29-4] A liquid composition was obtained in the same manner as in Examples 1-1 to 1-4, except that propylene glycol monopropyl ether was used as the solvent B (see Table 4).

[0132] [Examples 30-1 to 30-4] A liquid composition was obtained in the same manner as in Examples 10-1 to 10-4, except that propylene glycol monopropyl ether was used as the solvent B (see Table 4).

[0133] [Examples 31-1 to 31-4] A liquid composition was obtained in the same manner as in Examples 20-1 to 20-4, except that propylene glycol monopropyl ether was used as the solvent B (see Table 4).

[0134] [Examples 32-1 to 32-4] A liquid composition was obtained in the same manner as in Examples 4-1 to 4-4, except that propylene glycol monopropyl ether was used as the solvent B (see Table 4).

[0135] [Examples 33-1 to 33-4] A liquid composition was obtained in the same manner as in Examples 9-1 to 9-4, except that propylene glycol monopropyl ether was used as the solvent B (see Table 4).

[0136] [Examples 34-1 to 34-4] A liquid composition was obtained in the same manner as in Examples 4-1 to 4-4, except that ethyl lactate was used as solvent A and hexylene glycol was used as solvent B (see Table 5).

[0137] [Examples 35-1 to 35-4] Except for using ethylene glycol diacetate as the solvent B, liquid compositions were obtained in the same manner as in Examples 34-1 to 34-4 (see Table 5).

[0138] [Examples 36-1 to 35-4] Except for using furfuryl alcohol as the solvent B, liquid compositions were obtained in the same manner as in Examples 34-1 to 34-4 (see Table 5).

[0139] [Examples 37-1 to 37-4] A liquid composition was obtained in the same manner as in Examples 4-1 to 4-4, except that 2-pentanone was used as the solvent A and hexylene glycol was used as the solvent B (see Table 5).

[0140] [Examples 38-1 to 38-4] Except for using ethylene glycol diacetate as the solvent B, liquid compositions were obtained in the same manner as in Examples 37-1 to 37-4 (see Table 5).

[0141] [Examples 39-1 to 39-4] A liquid composition was obtained in the same manner as in Examples 4-1 to 4-4, except that ethylene glycol diacetate was used as solvent A and hexylene glycol was used as solvent B (see Table 6).

[0142] [Comparative Examples 29-1 to 29-4] A liquid composition was obtained in the same manner as in Examples 4-1 to 4-4, except that cyclohexanone was used as the solvent A and hexylene glycol was used as the solvent B (see Table 6).

[0143] [Examples 40-1 to 40-4] Liquid compositions were obtained in the same manner as in Examples 39-1 to 39-4, except that diacetone alcohol was used as the solvent A (see Table 6).

[0144] [Comparative Examples 30-1 to 30-2, Examples 41-1 to 41-2] Except for using isopropyl alcohol as the solvent A, liquid compositions were obtained in the same manner as in Examples 39-1 to 39-4 (see Table 6).

[0145] [Comparative Examples 31-1 to 31-4] Except for using 1-methyl-2-pyrrolidone as the solvent A, liquid compositions were obtained in the same manner as in Examples 39-1 to 39-4 (see Table 6).

[0146] [Comparative Examples 32-1 to 32-4] Except for using ethyl acetate as the solvent A, liquid compositions were obtained in the same manner as in Examples 39-1 to 39-4 (see Table 7).

[0147] [Comparative Examples 33-1 to 33-4] Except for using butyl acetate as solvent A, liquid compositions were obtained in the same manner as in Examples 39-1 to 39-4 (see Table 7).

[0148] [Comparative Examples 34-1 to 34-4] Except for using 2-butanone as the solvent A, liquid compositions were obtained in the same manner as in Examples 39-1 to 39-4 (see Table 7).

[0149] [Comparative Examples 35-1 to 35-4] Except for using dimethyl sulfoxide as the solvent A, liquid compositions were obtained in the same manner as in Examples 39-1 to 39-4 (see Table 7).

[0150] [Comparative Examples 36-1 to 36-4] Except for using diisobutyl ketone as the solvent A, liquid compositions were obtained in the same manner as in Examples 39-1 to 39-4 (see Table 7).

[0151] [Preparation of absorbing medium] A negative electrode composite layer slurry obtained by kneading a negative electrode active material SCMG-XRs (manufactured by Showa Denko), water, and a resin was applied onto a copper foil as a negative electrode substrate, and then dried to form a negative electrode composite layer, which was used as an absorption medium.

[0152] [Preparation of negative electrode integrated separator] A liquid composition was discharged onto an absorbent medium using a liquid discharger EV2500 and a liquid discharge head MH5421F (both manufactured by Ricoh), and then dried to form a particle layer, thereby obtaining a negative electrode integrated separator. 2 The discharge conditions were appropriately set so that

[0153] Here, the basis weight is the mass per unit area of ​​the particle layer formed on the absorbent medium.

[0154] Next, the thickness of the particle layer and the electrical insulation resistance of the negative electrode integrated separator were measured, and the coffee ring was evaluated.

[0155] [Particle layer thickness] The thickness of the particle layer was calculated by comparing the thickness before and after the formation of the particle layer using a micro depth gauge, and was observed using a scanning electron microscope (SEM) if necessary.

[0156] [Electrical insulation resistance of negative electrode integrated separator] The negative electrode-integrated separator was punched out to a diameter of 15 mm, and then the back side of the copper foil (the side on which the particle layer was not formed) and the particle layer were sandwiched between a resistance measuring tool HS flat cell (manufactured by Hohsen) to measure the resistance between the two surfaces, thereby obtaining the electrical insulation resistance of the electrode-integrated separator.

[0157] [Coffee Ring] The particle layer was visually observed to check whether or not a coffee ring had occurred.

[0158] Tables 1 to 7 show the measurement results of the particle layer thickness, the electrical insulation resistance of the negative electrode integrated separator, and the evaluation results of the coffee ring.

[0159] [Table 1]

[0160] [Table 2]

[0161] [Table 3]

[0162] [Table 4]

[0163] [Table 5]

[0164] [Table 6]

[0165] [Table 7] It can be seen from Tables 1 to 7 that when the inks of the examples are used, the electrical insulation resistance of the electrode-integrated separator increases and coffee ring does not occur.

[0166] In contrast, the liquid compositions of Comparative Examples 5-1, 28-1, 28-2, 30-1, and 30-2 have a surface tension against air of less than 25 mN / m, and therefore the electrical insulation resistance of the electrode-integrated separator is low.

[0167] The liquid compositions of Comparative Examples 12-1 to 12-4, 13-1 to 13-4, 14-1 to 14-4, 15-1 to 15-4, 29-1 to 29-4, 31-1 to 31-4, 32-1 to 32-4, 33-1 to 33-4, 34-1 to 34-4, 35-1 to 35-4, and 36-1 to 36-4 were D 90A+B Since the particle size exceeded 2 μm, the dispersibility was low and it was not possible to prepare a negative electrode-integrated separator.

[0168] The liquid compositions of Comparative Examples 22 and 23 had a surface tension relative to air of more than 50 mN / m, and therefore produced a coffee ring. [Explanation of symbols]

[0169] 30 Separator integrated electrode 31 Electrode base 32 Electrode composite layer 33 Particle layer [Prior art documents] [Patent documents]

[0170] [Patent Document 1] JP 2000-277386 A [Patent Document 2] JP 2006-173001 A

Claims

1. A liquid composition for an electrode-integrated separator, comprising insulating particles, a resin having a dispersible group and an adsorptive group, a solvent A, and a solvent B different from the solvent A, said solvent A being a lactam, an alcohol, a sulfoxide, an ester or a ketone; said solvent B being an ether, a glycol, an ester, an alcohol or a lactam; The surface tension with respect to air at 25°C is 25 mN / m or more and less than 50 mN / m, The 90% diameter is 2.5 μm or less, A liquid composition for an electrode-integrated separator, characterized in that the median diameter is 1 μm or less.

2. The liquid composition for an electrode-integrated separator according to claim 1 , wherein the insulating particles are inorganic particles.

3. A liquid composition for an electrode-integrated separator, comprising insulating particles, a resin having a dispersible group and an adsorptive group, a solvent A, and a solvent B different from the solvent A, said solvent A being a lactam, an alcohol, a sulfoxide, an ester or a ketone; said solvent B being an ether, a glycol, an ester, an alcohol or a lactam; The median diameter is D ５０Ａ＋Ｂ [μm], 90% diameter is D ９０Ａ＋Ｂ [μm], the median diameter of the dispersion obtained by removing the solvent B from the liquid composition for an electrode-integrated separator is D ５０Ａ [μm], the median diameter of the dispersion obtained by removing the solvent A from the liquid composition for an electrode-integrated separator is D ５０Ｂ If [μm], the formula 1<D ５０Ｂ / D ５０Ａ 1<D ５０Ａ＋Ｂ / D ５０Ａ <1.1 D ９０Ａ＋Ｂ <5 1. A liquid composition for an electrode-integrated separator, comprising:

4. A liquid composition for an electrode-integrated separator, the liquid composition being produced by adding a solvent B different from the solvent A to a dispersion liquid containing insulating particles, a resin having a dispersible group and an adsorptive group, and a solvent A, said solvent A being a lactam, an alcohol, a sulfoxide, an ester or a ketone; said solvent B being an ether, a glycol, an ester, an alcohol or a lactam; The surface tension with respect to air at 25°C is 25 mN / m or more and less than 50 mN / m, The 90% diameter is 2.5 μm or less, The liquid composition for an electrode-integrated separator, wherein the dispersion has a median diameter of 1 μm or less.

5. A method for producing a particle layer, comprising a coating step of coating the liquid composition for an electrode-integrated separator according to claim 1 onto an absorbent medium having a porous structure.

6. The method for producing a particle layer according to claim 5 , wherein the absorption medium is an electrode substrate on which an electrode mixture layer containing an active material is formed.

7. The method for producing a particle layer according to claim 5 or 6, wherein the coating step is performed by a liquid ejection method.

8. A method for producing an electrode, comprising the method for producing a particle layer according to any one of claims 5 to 7.

9. A method for producing an electrochemical device, comprising the method for producing an electrode according to claim 8.

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