TWI575011B - Resin composition for electrode of supercapacitor, slurry, electrode and supercapacitor - Google Patents

Description

Resin composition for supercapacitor electrodes, slurry, electrode and supercapacitor

The present invention relates to a resin composition for a supercapacitor electrode, a slurry for a supercapacitor electrode, a supercapacitor electrode, and a supercapacitor. In particular, regarding a resin composition for a supercapacitor electrode, the supercapacitor electrode slurry prepared by the method can produce a supercapacitor electrode having excellent adhesion between an electrode layer and a current collector, a slurry for a supercapacitor electrode, and a super a capacitor electrode, and a supercapacitor having the supercapacitor electrode.

Supercapacitor (SC), also known as electrical double layer capacitor (EDLC), which has higher energy density than general batteries, and has the advantages of fast charge and discharge and high cycle life. Widely used in the field of energy storage.

A supercapacitor is an electrochemical device that stores electrical energy on an electrode in an electrical double layer manner. The energy storage and release of the supercapacitor comes from the electric double layer structure formed by electrostatic charge adsorption. Due to the reverse charging and discharging process of such an electric double layer structure, It does not cause loss of the electrolyte and the electrode in the electrochemical reaction process of the general battery, so it has excellent reversible electric power and high cycle life. However, in the process of the electrode of the supercapacitor, after the winding step, the electrode layer on the current collector is easily peeled off, and the energy storage efficiency of the capacitor is not good.

Therefore, how to improve the adhesion between the electrode layer and the current collector is a problem that those skilled in the art are currently trying to solve.

In view of the above, the present invention provides a resin composition for a supercapacitor electrode and a slurry for a supercapacitor electrode prepared thereby, and a supercapacitor electrode having excellent adhesion between an electrode layer and a current collector can be produced.

The present invention provides a resin composition for a supercapacitor electrode comprising a first polymer. The first polymer includes a first core portion and a first cladding layer overlying a surface of the first core portion. The content of the first core portion is from 82 parts by weight to 92 parts by weight based on 100 parts by weight of the first polymer, and the content of the first cladding layer is from 8 parts by weight to 18 parts by weight. The first polymer has an average particle diameter of from 305 nm to 520 nm.

In an embodiment of the invention, the first polymer has an average particle diameter of from 315 nm to 495 nm.

In an embodiment of the invention, the first core portion includes a first structural unit represented by the formula (1) and a second structural unit other than the first structural unit. The content of the first structural unit is from 90% by weight to 99.9% by weight, and the content of the second structural unit is from 0.1% by weight to 10% by weight based on 100% by weight of the first core portion.

In the formula (1), R ¹ is a hydrogen atom or a methyl group, and R ² is an alkyl group having 4 to 10 carbon atoms.

In an embodiment of the invention, the first cladding layer comprises an ethylenically unsaturated carboxylic acid structural unit, an ethylenically unsaturated carboxylic acid ester structural unit, and an aromatic vinyl structural unit. The content of the ethylenically unsaturated carboxylic acid structural unit is 5% by weight to 15% by weight, and the content of the ethylenically unsaturated carboxylic acid ester structural unit is 70% by weight to 90% by weight based on 100% by weight of the first coating layer. The content of the aromatic vinyl structural unit is from 5% by weight to 15% by weight.

In an embodiment of the invention, the first core portion has an average particle diameter of from 300 nm to 490 nm.

In an embodiment of the invention, the resin composition for a supercapacitor electrode described above further comprises a second polymer having an average particle diameter of from 50 nm to 150 nm.

In an embodiment of the invention, the second polymer includes a second core portion and a second cladding layer covering the surface of the second core portion. The content of the second core portion is from 82 parts by weight to 92 parts by weight based on 100 parts by weight of the second polymer, and the content of the second coating layer is from 8 parts by weight to 18 parts by weight.

In an embodiment of the invention, the second core portion includes the first structural unit represented by the above formula (1) and the second structural structure other than the first structural unit. unit. The content of the first structural unit is from 90% by weight to 99.9% by weight based on 100% by weight of the second core portion, and the content of the second structural unit is from 0.1% by weight to 10% by weight.

In an embodiment of the invention, the resin composition for a supercapacitor electrode described above further includes water.

The present invention further provides a slurry for a supercapacitor electrode comprising the above-described resin composition for a supercapacitor electrode and an active material.

The present invention also provides a supercapacitor electrode comprising a current collector and an electrode layer on a surface of the current collector, wherein the electrode layer is obtained from the slurry for the supercapacitor electrode described above.

The present invention also provides a supercapacitor comprising: two electrodes and an electrolyte between the electrodes, wherein at least one of the electrodes is the supercapacitor electrode described above.

Based on the above-described slurry for a supercapacitor electrode prepared by using a resin composition for a supercapacitor electrode containing a polymer having a specific composition, a supercapacitor electrode having excellent adhesion between an electrode layer and a current collector can be produced. Therefore, when applied to a supercapacitor, the energy storage efficiency of the capacitor can be effectively improved.

The above described features and advantages of the present invention will be more apparent from the following description.

100‧‧‧Winding supercapacitors

110‧‧‧ Main body

110a‧‧‧Cylindrical surface

110b‧‧‧ bottom

110c‧‧‧ top surface

112‧‧‧ positive

112a, 112c, 116a, 116c‧‧‧ electrode layers

112b, 116b‧‧‧ Collector

114‧‧‧ Electrolytes

116‧‧‧negative

120‧‧‧ wire

130‧‧‧Package housing

140‧‧‧ Sealing elements

H‧‧‧Tongkong

L‧‧‧ laminated structure

S1‧‧‧ diaphragm

S2‧‧‧ diaphragm

1A is an exploded view of a wound type supercapacitor in accordance with an embodiment of the present invention.

1B is a schematic diagram of the interior of a wound type supercapacitor in accordance with an embodiment of the present invention.

Fig. 2 is a schematic cross-sectional view taken along line I-I' of Fig. 1B.

<Resin composition for super capacitor electrode>

The present invention provides a resin composition for a supercapacitor electrode comprising a first polymer having a large average particle diameter. Further, the resin composition for a supercapacitor electrode may further include a second polymer having a smaller average particle diameter. Hereinafter, the first polymer and the second polymer and a method of producing the same are explained.

First polymer

The first polymer includes a first core portion and a first cladding layer overlying a surface of the first core portion.

The first core portion includes a first structural unit represented by the formula (1) and a second structural unit other than the first structural unit.

In the formula (1), R ¹ is a hydrogen atom or a methyl group, and R ² is an alkyl group having 4 to 10 carbon atoms.

The first structural unit is derived from the first monomer represented by the formula (2).

In the formula (2), R ¹ and R ² have the same meanings as R ¹ and R ² in the formula (1), and are not described herein.

Specific examples of the first monomer include, but are not limited to, n-butyl acrylate, isobutyl acrylate, n-amyl acrylate, isoamyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate, 2,2-diethyl acrylate Alkyl acrylate such as hexyl hexyl ester; n-butyl methacrylate, isobutyl methacrylate, n-amyl methacrylate, isoamyl methacrylate, n-hexyl methacrylate, 2-ethyl methacrylate An alkyl methacrylate such as hexyl ester or 2,2-diethylhexyl methacrylate or a combination of the above compounds.

The first monomers may be used singly or in combination of two or more.

Specific examples of the first monomer are preferably n-butyl acrylate, 2-ethylhexyl acrylate, or a combination of the above compounds.

The content of the first structural unit is preferably from 90% by weight to 99.9% by weight, and more preferably from 95% by weight to 99.7% by weight, based on 100% by weight of the first core portion.

The second structural unit is derived from the second monomer. The second monomer is not particularly limited, and is, for example, glycidyl acrylate, glycidyl methacrylate (GMA), ethylene glycol diacrylate. (ethylene glycol diacrylate), ethylene glycol dimethacrylate, allyl acrylate, allyl methacrylate (AMA) and other (meth) acrylate series Body, or a combination of the above compounds.

The content of the second structural unit is from 0.1% by weight to 10% by weight, preferably from 0.3% by weight to 5% by weight, based on 100% by weight of the first core portion.

When the content of the first structural unit and the second structural unit is within the above range, the electrode layer of the supercapacitor electrode and the current collector made of the resin composition for the supercapacitor electrode are 100% by weight of the first core portion. The adhesion is better.

In an embodiment of the invention, the first core portion can be obtained by emulsion polymerization of the first monomer and the second monomer in the presence of water, an emulsifier, and a polymerization initiator. Specific examples of the first monomer and the second monomer have been described above and will not be further described herein. In addition, the content of the first monomer and the second monomer is about 100% by weight of the monomer mixture for synthesizing the first core portion, and the content of the first structural unit and the second structural unit is about the same as the content of the first structural unit and the second structural unit of the polymer. This will not be repeated here.

The water is, for example, deionized water, ultrapure water, ion exchanged water, reverse osmosis water or distilled water. The water may be used in an amount of from 100 parts by weight to 1,000 parts by weight based on 100 parts by weight of the monomer mixture of the first core portion.

Specific examples of the emulsifier include, but are not limited to, anionic surfactants such as sulfate esters of higher alcohols, alkylbenzenesulfonates (such as sodium dodecylbenzenesulfonate), and alkyl diphenyl ether disulfonates. , aliphatic sulfonate, aliphatic carboxylate; non-ionic watch A surfactant, such as a polyethylene glycol alkyl ester type, an alkylphenyl ether type, an alkyl ether; or a combination of the above emulsifiers. A specific example of the emulsifier is preferably sodium dicyclohexyl sulfosuccinate (trade name: MA-80). The emulsifier may be used in an amount of from 0.2 part by weight to 1.5 parts by weight based on 100 parts by weight of the monomer mixture of the first core portion.

The polymerization initiator may be a radical polymerization initiator. Specific examples of the polymerization initiator include, but are not limited to, water-soluble polymerization initiators such as potassium persulfate, sodium persulfate, ammonium persulfate, etc.; oil-soluble polymerization initiators such as cumene hydroperoxide , benzoyl peroxide, tert-butyl hydroperoxide (BHP), acetonitrile hydrogen peroxide, diisopropylbenzene hydrogen peroxide, 1,1,3,3-tetramethyl Butyl hydrogen peroxide; or a combination of the above polymerization initiators. A specific example of the polymerization initiator is preferably tert-butyl hydroperoxide. The polymerization initiator may be used in an amount of from 0.01 part by weight to 5 parts by weight based on 100 parts by weight of the monomer mixture of the first core portion.

The emulsion polymerization can also be carried out in the presence of other additives. Other additives may, for example, be an anti-aging agent, a preservative, a dispersing agent, a tackifier, or a combination of the other additives mentioned above.

The emulsion polymerization reaction is not particularly limited, and batch polymerization, semi-batch polymerization, seed polymerization, or the like can be used. Further, the method of adding the various components is not particularly limited, and a single addition method, a fractional addition method, a continuous addition method, or a power feeding method can be used.

The temperature of the emulsion polymerization may be from 40 to 100 ° C, preferably from 50 to 90 ° C. The reaction time of the emulsion polymerization reaction may be 2 to 12 hours, preferably 3 to 8 hours. Time.

After the emulsion polymerization, a solution containing the first core portion and water can be obtained, and the solution can be further concentrated under reduced pressure to obtain a first core portion solution having a solid content of 10% by weight to 30% by weight.

The average particle diameter of the first core portion is preferably from 300 nm to 490 nm, more preferably from 305 nm to 465 nm. When the average particle diameter of the first core portion is within the above range, the adhesion between the electrode layer of the supercapacitor electrode and the current collector produced by the resin composition for the supercapacitor electrode is preferable.

The content of the first core portion is from 82 parts by weight to 92 parts by weight, preferably from 82 parts by weight to 90 parts by weight, more preferably from 85 parts by weight to 90 parts by weight, based on 100 parts by weight of the first polymer. When the content of the first core portion is less than 82 parts by weight or more than 92 parts by weight, the adhesion between the electrode layer of the supercapacitor electrode and the current collector produced by the resin composition for the supercapacitor electrode is not good.

The first cladding layer includes an ethylenically unsaturated carboxylic acid structural unit, an ethylenically unsaturated carboxylic acid ester structural unit, and an aromatic vinyl structural unit.

The ethylenically unsaturated carboxylic acid structural unit is derived from an ethylenically unsaturated carboxylic acid monomer. Specific examples of the ethylenically unsaturated carboxylic acid monomer include, but are not limited to, acrylic acid, methacrylic acid, maleic acid, crotonic acid, itaconic acid, fumaric acid, or a combination of the above compounds. The ethylenically unsaturated carboxylic acid monomers may be used singly or in combination of two or more. Specific examples of the ethylenically unsaturated carboxylic acid monomer preferably include acrylic acid, methacrylic acid, itaconic acid, or a combination of the above compounds. The content of the ethylenically unsaturated carboxylic acid structural unit is preferably from 5% by weight to 15% by weight based on 100% by weight of the first coating layer. The % by weight, more preferably from 6% by weight to 14% by weight, most preferably from 8% by weight to 12% by weight.

The ethylenically unsaturated carboxylic acid ester structural unit is derived from an ethylenically unsaturated carboxylic acid ester monomer. Specific examples of the ethylenically unsaturated carboxylic acid ester monomer include, but are not limited to, alkyl acrylate such as methyl acrylate, ethyl acrylate or propyl acrylate; methacrylic acid such as methyl methacrylate or ethyl methacrylate; An alkyl ester; an alkyl maleate such as dimethyl maleate or diethyl maleate; an alkyl itaconate such as dimethyl itaconate; An alkyl fumarate such as monomethyl diacid, monoethyl fumarate, dimethyl fumarate or diethyl fumarate, or a combination of the above compounds. The ethylenically unsaturated carboxylic acid ester monomers may be used singly or in combination of two or more. Specific examples of the ethylenically unsaturated carboxylic acid ester monomer preferably include methyl methacrylate, butyl acrylate, 2-ethylhexyl acrylate, or a combination of the above compounds. The content of the ethylenically unsaturated carboxylic acid structural unit is preferably from 70% by weight to 90% by weight, more preferably from 72% by weight to 88% by weight, most preferably 75% by weight based on 100% by weight of the first coating layer. % to 85% by weight.

The aromatic vinyl structural unit is derived from an aromatic vinyl monomer. Specific examples of the aromatic vinyl monomer include, but are not limited to, styrene, α-methylstyrene, methyl-α-methylstyrene, vinyltoluene, divinylbenzene, or a combination of the above compounds. The aromatic vinyl monomers may be used singly or in combination of two or more. A specific example of the aromatic vinyl monomer is preferably styrene or α-methylstyrene, or a combination of the above compounds. The content of the aromatic vinyl structural unit is preferably from 5% by weight to 15% by weight, more preferably from 6% by weight to 14% by weight based on 100% by weight of the first coating layer. The amount % is preferably from 8% by weight to 12% by weight.

The monomer constituting the first cladding layer may further include other monomers such as an acrylonitrile monomer, a conjugated diene monomer or a guanamine monomer.

Specific examples of the acrylonitrile-based monomer include, but are not limited to, acrylonitrile, α-methacrylonitrile, or a combination of the above compounds.

Specific examples of the conjugated diene monomer include, but are not limited to, 1,3-butadiene, isoprene, 1,3-pentadiene, 2-ethyl-1,3-butadiene, 2, 3-dimethylbutadiene, 2-methylpentadiene, 4-methylpentadiene, 2,4-hexadiene, or a combination of the above compounds.

Specific examples of the amide-based monomer include, but are not limited to, acrylamide, methacrylamide, N-methylol acrylamide, N-methylol methacrylamide, N, N-di N,N-dimethylacrylamide, N,N-dimethylmethacrylamide, or a combination of the above compounds.

When the content of the ethylenically unsaturated carboxylic acid structural unit, the ethylenically unsaturated carboxylic acid ester structural unit, and the aromatic vinyl structural unit is within the above range, the supercapacitor electrode is used in an amount of 100% by weight of the first coating layer. The adhesion between the electrode layer of the supercapacitor electrode produced by the resin composition and the current collector is preferable.

The first cladding layer is formed by adding a monomer constituting the first cladding layer to the first core portion solution to carry out a graft reaction, so that a first cladding layer can be formed on the surface of the first core portion. The graft reaction temperature may be from 40 to 100 ° C, preferably from 50 to 90 ° C. The reaction time of the graft reaction may be 2 to 10 hours, preferably 2 to 6 hour.

The content of the first coating layer is from 8 parts by weight to 18 parts by weight, preferably from 10 parts by weight to 18 parts by weight, more preferably from 10 parts by weight to 15 parts by weight, based on 100 parts by weight of the first polymer. When the content of the first cladding layer is less than 8 parts by weight or more than 18 parts by weight, the adhesion between the electrode layer of the supercapacitor electrode and the current collector produced by the resin composition for the supercapacitor electrode is not good.

After the grafting reaction, a solution containing the first polymer and water can be obtained, and the solution can be further concentrated under reduced pressure to obtain a first polymer solution having a solid content of 20% by weight to 40% by weight. The first polymer solution is a resin composition for a supercapacitor electrode according to an embodiment of the present invention, and may further include water used for synthesizing the first polymer, in addition to the first polymer.

The first polymer has an average particle diameter of from 305 nm to 520 nm, preferably from 315 nm to 495 nm. When the average particle diameter of the polymer is less than 305 nm, the adhesion between the electrode layer of the supercapacitor electrode and the current collector produced by the resin composition for the supercapacitor electrode is not good. Further, from the viewpoint of synthesis, a polymer having an average particle diameter of more than 520 nm is difficult to obtain.

Second polymer

The second polymer includes a second core portion and a second cladding layer overlying a surface of the second core portion.

The second core portion includes the first structural unit represented by the above formula (1) and the second structural unit other than the first structural unit. 100% by weight with the second core The content of the first structural unit is preferably from 90% by weight to 99.9% by weight, and the content of the second structural unit is preferably from 0.1% by weight to 10% by weight.

Further, the content of the second core portion is preferably from 82 parts by weight to 92 parts by weight based on 100 parts by weight of the second polymer, and the content of the second coating layer is preferably from 8 parts by weight to 18 parts by weight.

The composition and preparation method of the second core portion and the second cladding layer are the same as the first core portion and the first cladding layer of the first polymer, respectively, and are not described here, but the difference is: the amount of the emulsifier The average particle size with the second polymer.

The emulsifier may be used in an amount of from 2.2 parts by weight to 2.8 parts by weight based on 100 parts by weight of the monomer mixture of the second core portion.

The average particle diameter of the second polymer is preferably from 50 nm to 150 nm. When the resin composition for a supercapacitor electrode includes a second polymer having an average particle diameter smaller than that of the first polymer, since the gap between the first polymers can be filled, the electrode layer and the current collector can be further raised. Closeness. Therefore, the energy storage efficiency of the supercapacitor is better.

It is to be noted that, in the case where the resin composition for a supercapacitor electrode according to an embodiment of the present invention includes the second polymer, the resin composition for the supercapacitor electrode may be mixed with the first polymer solution and the second polymer solution. And got it. If necessary, it may be further concentrated under reduced pressure to obtain a solution having a solid content of 25% by weight to 35% by weight. As such, the resin composition for a supercapacitor electrode includes water in addition to the first polymer and the second polymer.

<Supercapacitor electrode slurry>

The present invention further provides a slurry for a supercapacitor electrode comprising the above-described resin composition for a supercapacitor electrode and an active material. In addition, the slurry for the supercapacitor electrode may further include at least one additive such as an etchant, a conductive auxiliary, a tackifier, a dispersant, a stabilizer, and additionally added water, if necessary.

Specific examples of the active material include, but are not limited to, conductive carbonaceous materials such as natural graphite, artificial graphite or activated carbon. The artificial graphite is, for example, a graphitized person such as petroleum, coal pitch or coke. The conductive polymer is, for example, a polyacene organic semiconductor, a polyacetylene, a polyparaphenylene group, or a combination of the above carbides.

The etchant has no other limitation as long as it can partially etch the surface of the current collector described above and roughen the surface of the current collector. Specific examples of the etchant include, but are not limited to, an organic acid such as formic acid, acetic acid, oxalic acid, malonic acid, malic acid, tartaric acid, succinic acid or propionic acid; or an inorganic acid such as hydrochloric acid, phosphoric acid or sulfuric acid.

Specific examples of the conductive auxiliary agent include, but are not limited to, carbon black such as acetylene black or Ketjenblack; carbon nanofibers such as fumed carbon fibers; conductive carbon such as carbon nanotubes and graphite fine powder, or carbonization described above. a combination of things.

Specific examples of the tackifier include, but are not limited to, carboxymethylcellulose, methylcellulose, hydroxymethylcellulose, ethylcellulose, polyvinyl alcohol, polyacrylic acid (salt), oxidized starch, phosphorylated starch, and cheese. Protein, or a combination of the above tackifiers. A specific example of the tackifier is preferably methyl cellulose.

Specific examples of the dispersing agent include, but are not limited to, sodium hexametaphosphate and tripolyphosphoric acid. Sodium, sodium pyrophosphate, sodium polyacrylate, and the like.

Specific examples of the stabilizer include, but are not limited to, a nonionic surfactant, an anionic surfactant, or a combination thereof.

Water can be used to increase the uniformity of the slurry. Specific examples of the water are the same as those used in the case of the synthetic polymer, and are not described herein.

The method for preparing the slurry for a supercapacitor electrode is not particularly limited as long as the resin composition for the supercapacitor electrode and the active material can be mixed. Specifically, the method of mixing the resin composition for a supercapacitor electrode and the active material is, for example, stirring with a magnetic stirrer or stirring with a mechanical stirrer. In the slurry for a supercapacitor electrode of the present invention, the resin composition for a supercapacitor electrode is used in an amount of from 1 part by weight to 40 parts by weight, based on 100 parts by weight of the active material, preferably from 5 parts by weight to 30 parts by weight. The slurry for the supercapacitor electrode has a solid content of 20% by weight to 35% by weight.

<Supercapacitor electrode and preparation method thereof>

The present invention further provides a supercapacitor electrode comprising a current collector and an electrode layer on a surface of the current collector, wherein the electrode layer is obtained from the slurry for a supercapacitor electrode described above.

The supercapacitor electrode is formed by applying a slurry for a supercapacitor electrode as described above to at least one of an upper surface and a lower surface of a current collector, and drying or the like.

The collector is, for example, a metal such as aluminum, titanium, tantalum, iron, copper, nickel or stainless steel. material. The metal material may be in the form of a sheet (metal foil), a film or a mesh.

The method of applying the slurry for a supercapacitor electrode to a current collector can be performed by a doctor blade method, a dipping method, a direct roll method, a gravure printing method, an extrusion method, a brush coating method, a reverse roll method, or an air knife method. .

The drying method may be a dry drying, a blower dryer, a warm air dryer, an infrared heater, a far infrared heater or the like. The drying temperature is usually 50 ° C or more.

<supercapacitor>

The resin composition for a supercapacitor electrode, the slurry for a supercapacitor electrode, and the supercapacitor electrode of the present invention can be applied to various known supercapacitors. For example, a wound type super capacitor, a laminated type super capacitor or a button type super capacitor. The resin composition for a supercapacitor electrode and the slurry for a supercapacitor electrode of the present invention can effectively improve the energy storage efficiency of the capacitor because of the excellent adhesion between the electrode layer and the current collector.

1A is an exploded view of a wound type supercapacitor in accordance with an embodiment of the present invention. 1B is a schematic diagram of the interior of a wound type supercapacitor in accordance with an embodiment of the present invention. Please refer to FIG. 1A and FIG. 1B at the same time. The wound supercapacitor 100 includes a body portion 110, two wires 120, a package housing 130, and a sealing member 140. The material of the wire 120 is, for example, a metal such as gold, silver, copper, nickel or stainless steel. The material of the package housing 130 is, for example, a metal such as aluminum, iron, copper, nickel or stainless steel. The sealing element 140 is for example made of rubber, Teflon or plastic sheet.

The body portion 110 is a cylinder. The main body portion 110 has a cylindrical surface 110a and a bottom The surface 110b and the top surface 110c, wherein the bottom surface 110b and the top surface 110c are located on opposite sides of the cylindrical surface 110a. The main body portion 110 is obtained by winding a laminated structure L including the positive electrode 112 and the negative electrode 116. The two wires 120 are electrically connected to the positive electrode 112 and the negative electrode 116, respectively. The package housing 130 covers the cylindrical surface 110a and the bottom surface 110b of the main body portion 110. The sealing member 140 is located on the top surface 110c of the body portion 110 and has two through holes H. The two wires 120 are electrically connected to the outside through the two through holes H of the sealing member 140, respectively.

Fig. 2 is a schematic cross-sectional view taken along line I-I' of Fig. 1B. The laminated structure L is sequentially laminated from left to right into a positive electrode 112, a separator S1, an electrolyte 114, a negative electrode 116, and a separator S2. The electrolyte 114 is located between the positive electrode 112 and the negative electrode 116. The separator S1 is located between the positive electrode 112 and the electrolyte 114. The separator S2 is located on the side of the negative electrode 116 opposite to the electrolyte 114, that is, the negative electrode 116 is located between the electrolyte 114 and the separator S2.

The positive electrode 112 includes an electrode layer 112a, a current collector 112b, and an electrode layer 112c, wherein the current collector 112b is located between the electrode layer 112a and the electrode layer 112c. The electrode layer 112c is located beside the diaphragm S1. The anode 116 includes an electrode layer 116a, a current collector 116b, and an electrode layer 116c, wherein the current collector 116b is located between the electrode layer 116a and the electrode layer 116c. Electrode layer 116a is located next to electrolyte 114. At least one of the positive electrode 112 and the negative electrode 116 is the above-described supercapacitor electrode. From the viewpoint of adhesion, the positive electrode 112 and the negative electrode 116 are preferably the above-described supercapacitor electrodes. In another embodiment, at least one of the electrode layer 112a, the electrode layer 112c, the electrode layer 116a, and the electrode layer 116c is also a resin composition for the supercapacitor electrode described above.

The selection of the electrolyte 114 is not particularly limited, and a known supercapacitor electrolyte can be used as long as it does not affect the electrode layer on the supercapacitor electrode. The electrolyte 114 is, for example, a non-aqueous electrolyte solution in which an electrolyte such as a lithium salt or an ammonium salt is dissolved in an organic solvent; 1-ethyl-3-methylimidazolium dicyanamide, 1- Butyl-3,5-dimethylpyridinium bromide or 1-butyl-3-methylimidazolium hexafluorophosphate ) Room temperature ionic liquid, etc. In the non-aqueous electrolyte solution, the lithium salt is, for example, LiPF ₆ , LiBF ₄ , LiAsF ₆ , LiSbF ₆ , LiC(SO ₂ CF ₃ ) ₃ , LiN(SO ₂ CF ₃ ) ₂ or a combination thereof. The ammonium salt is, for example, triethylammonium monomethyltetrafluoroborate, tetraethylammonium tetrafluoroborate, tetraethylammonium hexafluorophosphate or a combination thereof. The organic solvent is, for example, γ-butyl lactone, ethylene carbonate (EC), propylene carbonate, butylene carbonate, diethyl carbonate (DEC), propyl acetate (PA). , dimethyl carbonate (DMC), ethylmethyl carbonate (EMC), cyclobutyl hydrazine, acetonitrile or a combination thereof. A specific example of the electrolyte 114 is preferably a propylene carbonate solution of triethylmonomethylammonium tetrafluoroborate.

The selection of the diaphragm S1 and the diaphragm S2 is not particularly limited, and a known or commercially available separator can be used. The separator may be, for example, an insulating material, glass fiber or cellulose, and the insulating material may be a microporous film or a non-woven fabric made of polyolefin such as polyethylene (PE), polypropylene (PP), or pulp.

Example

Hereinafter, the ratio of the various monomers in the monomer mixture is about the same as the ratio of each structural unit in the synthesized polymer.

Example 1 a. Preparation of resin composition for supercapacitor electrode A-1. Preparation of core solution

In a pressure-resistant reactor, 400 parts by weight of deionized water, 0.40 parts by weight of sodium dicyclohexyl sulfosuccinate (as emulsifier, trade name MA-80), and 100 parts by weight were placed. To form a monomer mixture of the core portion, wherein n-butyl acrylate (n-BA) is 99.7% by weight, based on 100% by weight of the monomer mixture for forming the core portion; allyl methacrylate (AMA) is 0.3% by weight. Next, after raising the temperature to 60 ° C, 0.15 part by weight of tert-butyl hydroperoxide (BHP) was added as a polymerization initiator, and the reaction was carried out for 7 hours. A core portion solution having a solid content of 20% by weight was obtained.

A-2. Preparation of resin composition for supercapacitor electrode

In a three-necked flask having a volume of 1000 ml, 410 parts by weight of a core solution and 290 parts by weight of deionized water were added, and the temperature was raised to 85 °C. Next, 15 parts by weight of a monomer mixture for forming a coating layer was added in an amount of 85 parts by weight based on the solid content of the core portion solution, wherein 100% by weight of the monomer mixture for forming the coating layer was used. The base acrylic acid (MAA) was 10% by weight; the styrene (SM) was 10% by weight; and the methyl methacrylate (MMA) was 80% by weight. Next, 0.6 parts by weight of ammonium persulfate (APS) was added as a polymerization initiator, and the reaction was carried out for 6 hours. Time. After completion of the reaction, the mixture was concentrated under reduced pressure to obtain a resin composition for a supercapacitor electrode having a solid content of 30% by weight in Example 1.

b. Preparation of slurry for supercapacitor electrode

2 parts by weight of methyl cellulose (as a tackifier), 16.7 parts by weight of a resin composition for a supercapacitor electrode, and 93 parts by weight of activated carbon (as an active material) were added to 254 parts by weight of deionized water, and mixed and stirred. Uniformly, a slurry having a solid content of 27% by weight of Example 1 was obtained.

c. Preparation of supercapacitor electrodes

The slurry was uniformly coated on an aluminum foil (as a current collector) by a doctor bar method, the thickness of the slurry was 200 μm, and the aluminum foil was placed in an oven. Bake at a temperature of 80 ° C for 30 minutes to dry the slurry. Then, the aluminum foil was rolled to prepare an electrode of Example 1 having a thickness of about 100 μm, a width of about 10 cm, and a length of about 30 cm. The obtained electrode was evaluated, and the evaluation method was as described later, and the results are shown in Table 2.

d. Preparation of supercapacitors

The electrode prepared above was wound together with a separator (cellulose) by a winder to form a main body portion, and the main body portion was connected to a wire. The main body portion, the cylindrical aluminum package case, and the rubber sealing member were vacuum-dried, and then the main body portion was inserted into the aluminum package case in the drying chamber. Next, an electrolyte solution in which the electrolyte solution is a propylene carbonate solution in which triethylmonomethylammonium tetrafluoroborate is dissolved is injected. Of course Thereafter, the supercapacitor of Example 1 was obtained by sealing with a sealing member.

Embodiment 2 to Embodiment 8

The resin composition, slurry, electrode, and supercapacitor for the supercapacitor electrode of Example 2 to Example 8 were prepared in the same manner as in Example 1. The only difference is that the composition of the resin composition for the supercapacitor electrode and the amount thereof (as shown in Table 2) are changed, and the compounds corresponding to the abbreviations in Table 2 are shown in Table 1. The obtained supercapacitor electrode was evaluated for the resin composition and the electrode, and the results are shown in Table 2.

Comparative Example 1 to Comparative Example 8

The resin composition for a supercapacitor electrode of Comparative Example 1 to Comparative Example 8, a slurry, an electrode, and a supercapacitor were prepared in the same manner as in Example 1. The only difference is that the composition of the resin composition for the supercapacitor electrode and the amount thereof (as shown in Table 3) are changed, and the compounds corresponding to the abbreviations in Table 3 are shown in Table 1. The obtained supercapacitor electrode was evaluated for the resin composition and the electrode, and the results are shown in Table 3.

Example 9

The resin composition, slurry, electrode, and supercapacitor for the supercapacitor electrode of Example 9 were prepared in the same manner as in Example 1, except that the resin composition for the supercapacitor electrode of Example 9 was 75. The resin composition for a supercapacitor electrode of Example 1 was composed of 25 parts by weight of the resin composition for a supercapacitor electrode of Comparative Example 1. The result of the adhesion evaluation was "○".

<Evaluation method> a. Average particle size determination

The resin composition for the supercapacitor electrode thus obtained was measured for the average particle diameter of the polymer by a dynamic light scattering method using a laser particle size analyzer (manufactured by MALVERN, model: nano-s90).

b. Adhesion

Take an electrode of 1 cm x 10 cm. Next, the electrode was bent so that one end thereof was wrapped around a roller having a diameter of 1 mm. Thereafter, in the case where the electrode is bent, the roller is rolled from one end of the electrode to the other end (referred to as bending once). After bending back and forth 10 times, the electrode layer on the aluminum foil was desorbed or peeled off from the aluminum foil. The evaluation criteria are as follows.

○: The surface of the electrode was smooth and the adhesion was good.

×: A crack occurred on the surface of the electrode or the electrode layer peeled off from the surface of the aluminum foil, indicating that the adhesion was poor.

<evaluation result>

Referring to Tables 2 and 3, Comparative Examples 3 and 4 in which the weight ratio is less than 82:18 compared with Examples 1 to 8 in which the weight ratio of the core portion to the cladding layer is 82:18 to 92:8. Comparative Example 7 having a weight ratio of 5, 6, or 8 and greater than 92:8 was inferior in adhesion. It can be seen that the content of the core portion is from 82 parts by weight to 92 parts by weight based on 100 parts by weight of the first polymer, and the electrode layer in the supercapacitor electrode The adhesion between the current collectors is good; when the content of the core portion is less than 82 parts by weight or more than 92 parts by weight, the adhesion between the electrode layer and the current collector in the supercapacitor electrode is poor.

The density of Comparative Examples 1, 2, 4, 5, and 7 having an average particle diameter of the polymer of less than 305 nm was compared with Example 1 to Example 8 in which the average particle diameter of the polymer was from 305 nm to 520 nm. Poor sex. It can be seen that when the average particle diameter of the polymer is from 305 nm to 520 nm, the adhesion between the electrode layer and the current collector in the supercapacitor electrode is good; when the average particle diameter of the polymer is less than 305 nm, The adhesion between the electrode layer and the current collector in the supercapacitor electrode is poor. In addition, polymers having an average particle diameter of more than 520 nm are difficult to synthesize.

Further, according to Example 9, when a resin composition for a supercapacitor electrode containing a polymer having an average particle diameter of 305 nm to 520 nm and a polymer having an average particle diameter of 50 nm to 150 nm is used, Super The adhesion between the electrode layer and the current collector in the capacitor electrode is good.

As described above, the present invention proposes a resin composition for a supercapacitor electrode. In the resin composition for a supercapacitor electrode, by controlling the weight ratio of the core portion to the coating layer in the polymer to be 82:18 to 92:8 and the average particle diameter of the polymer to be 305 nm to 520 nm, When the resin composition for a supercapacitor electrode is applied to a supercapacitor electrode, the adhesion between the electrode layer and the current collector in the supercapacitor electrode is good. Therefore, when applied to a supercapacitor, the energy storage efficiency of the capacitor can be effectively improved.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the invention, and any one of ordinary skill in the art without departing from the invention. In the spirit and scope, the scope of protection of the present invention is subject to the definition of the appended patent application.

112‧‧‧ positive

112a, 112c, 116a, 116c‧‧‧ electrode layers

112b, 116b‧‧‧ Collector

114‧‧‧ Electrolytes

116‧‧‧negative

L‧‧‧ laminated structure

S1‧‧‧ diaphragm

S2‧‧‧ diaphragm

Claims (10)

A resin composition for a supercapacitor electrode, comprising: a first polymer comprising a first core portion and a first cladding layer covering a surface of the first core portion, wherein the first polymer is 100 parts by weight, The content of the first core portion is 82 parts by weight to 92 parts by weight, the content of the first coating layer is 8 parts by weight to 18 parts by weight, and the average particle diameter of the first polymer is 305 nm to 520 nm. The first core portion includes a first structural unit represented by the formula (1) and a second structural unit other than the first structural unit, and the first core portion is 100% by weight, the first structure The content of the unit is from 90% by weight to 99.9% by weight, and the content of the second structural unit is from 0.1% by weight to 10% by weight, In the formula (1), R ¹ is a hydrogen atom or a methyl group, and R ² is an alkyl group having a carbon number of 4 to 10, and the first cladding layer comprises an ethylenically unsaturated carboxylic acid structural unit and an ethylenically unsaturated carboxylic acid. The ester structural unit and the aromatic vinyl structural unit, wherein the ethylenically unsaturated carboxylic acid structural unit is contained in an amount of from 5% by weight to 15% by weight based on 100% by weight of the first coating layer, and the ethylenically unsaturated carboxylic acid The content of the acid ester structural unit is from 70% by weight to 90% by weight, and the content of the aromatic vinyl structural unit is from 5% by weight to 15% by weight. The resin composition for a supercapacitor electrode according to claim 1, wherein the first polymer has an average particle diameter of from 315 nm to 495 nm. The resin composition for a supercapacitor electrode according to claim 1, wherein the first core portion has an average particle diameter of from 300 nm to 490 nm. The resin composition for a supercapacitor electrode according to claim 1, further comprising a second polymer having an average particle diameter of from 50 nm to 150 nm. The resin composition for a supercapacitor electrode according to claim 4, wherein the second polymer comprises a second core portion and a second cladding layer covering a surface of the second core portion, the second coating layer The content of the second core portion is from 82 parts by weight to 92 parts by weight based on 100 parts by weight of the polymer, and the content of the second cladding layer is from 8 parts by weight to 18 parts by weight. The resin composition for a supercapacitor electrode according to claim 5, wherein the second core portion includes a first structural unit represented by the formula (1) and a second structural unit other than the first structural unit, Wherein the content of the first structural unit is 90% by weight to 99.9% by weight, and the content of the second structural unit is 0.1% by weight to 10% by weight, based on 100% by weight of the second core portion, In the formula (1), R ¹ is a hydrogen atom or a methyl group, and R ² is an alkyl group having 4 to 10 carbon atoms. The resin composition for a supercapacitor electrode according to claim 1, further comprising water. A slurry for a supercapacitor electrode, comprising: a resin composition for a supercapacitor electrode according to any one of claims 1 to 7; and an active material. A supercapacitor electrode comprising: a current collector; and an electrode layer on the surface of the current collector, which is produced by using a slurry for a supercapacitor electrode according to claim 8 of the patent application. A supercapacitor comprising: two electrodes, at least one of which is a supercapacitor electrode as described in claim 9; and an electrolyte between the electrodes.