WO2023176989A1 - Separator for capacitor and graphene capacitor comprising same - Google Patents

Abstract

The present invention relates to a separator for a capacitor and a graphene capacitor comprising same. More specifically, the present invention relates to: a graphene-coated separator for a capacitor, the separator having improved durability, and being able to activate the electrolyte and positive electrode material of a capacitor and extend the lifespan of a capacitor; a graphene capacitor comprising same; and a production method for same.

Description

Separator for capacitors and graphene capacitors containing the same

The present invention relates to a separator for a capacitor and a graphene capacitor including the same. More specifically, the present invention provides a graphene-coated separator for a capacitor that has improved durability, can activate the electrolyte and anode of the capacitor, and can extend the life of the capacitor, a graphene capacitor containing the same, and a method of manufacturing the same. It's about.

Recently, the development of electrochemical energy storage devices applicable to digital devices, electronic devices, and electric vehicles (EV) fields has been active. Among energy storage devices developed until recently, super capacitors and lithium ion batteries (LIB) are known to be effective electrochemical energy storage devices.

Supercapacitors have the advantage of providing high power density and long cycle life with fast and stable charge/discharge capabilities through the formation of an electric double layer (EDL), but have the disadvantage of low energy density.

These supercapacitors can be broadly divided into electric double layer supercapacitors, pseudo supercapacitors, and hybrid supercapacitors.

Hybrid supercapacitor refers to a supercapacitor that uses different energy storage methods on both electrodes. In other words, a hybrid supercapacitor is a hybrid energy storage device that uses a cathode material that stores energy through oxidation/reduction reactions like a battery and an anode material that collects charges in an electric double layer like a storage battery (electric double layer capacitor). Lithium-ion hybrid supercapacitor (LIHS) is a combination of lithium ion insertion/extraction reaction of LIB type anode electrode and PF ^6- adsorption/desorption of EDL type cathode electrode.

Typically, a supercapacitor includes an anode and a cathode, and the two electrodes are separated by a porous separator. A porous separator between the electrodes allows the flow of ionic charge but prevents electrical contact between the electrodes.

The variables that have the greatest impact on the power density of a supercapacitor are electrodes, electrolyte, and It is the resistance of the separator. Previously, water-soluble and organic liquid electrolytes and porous polyolefin separators were used, or polyacrylic acid (PAA) and polyvinyl alcohol (PVA)-based polymer gel electrolytes containing KOH (potassium hydroxide) aqueous solution were used as electrolytes and separators. It has been used.

However, the porous polyolefin-based separator used in conventional technology has the advantage of having sufficient mechanical strength, but its porosity is usually 40-80%, which is significantly lower than that of non-woven fabrics, and the interfacial energy of the surface is lower than that of the electrolyte solvent, so its wettability in the electrolyte is greatly reduced. However, there were limitations in producing a separator electrolyte with high ionic conductivity. In addition, there is a disadvantage that the electrode and the separator are not integrated, which increases the interfacial resistance and causes leakage due to the use of a liquid electrolyte.

In addition, the polymer gel electrolyte separator improves leakage and safety, but still has low ionic conductivity and does not use a separate separator reinforcement, so its mechanical properties are low, making it difficult to manufacture ultra-high capacity capacitors and improve their characteristics.

Furthermore, there is a need to develop separator materials for use in supercapacitors that resist chemical degradation at high temperatures and pressures.

As background technology for the present invention, a lithium ion capacitor and a manufacturing method therefor are described in Korean Patent No. 10-1056512.

The purpose of the present invention is to provide a separator for a capacitor that improves the durability of the separator, activates the electrolyte and anode of the capacitor, and maintains the optimal condition of the capacitor to extend its lifespan.

Another object of the present invention is to efficiently manufacture a separator for a capacitor through a simple process, which can improve the durability of the separator, activate the electrolyte and anode of the capacitor, and extend the lifespan by maintaining the optimal capacitor condition. It provides a way to do it.

Another object of the present invention is to provide a graphene capacitor with improved durability, activated electrolyte and anode, and extended lifespan by maintaining an optimal capacitor condition.

The object of the present invention is not limited to the objects mentioned above, and other objects not mentioned can be clearly understood from the detailed description.

According to one aspect, a substrate; a ceramic layer formed on at least one side of the substrate; A separator for a capacitor is provided, including a graphene layer formed on the ceramic layer.

According to one embodiment, the ceramic layer and the graphene layer may be formed on both sides of the substrate.

According to one embodiment, the ceramic layer may include spherical alumina particles.

According to one embodiment, the ceramic layer and the graphene layer may further include one or more types of organic and inorganic binders.

According to one embodiment, the graphene layer may have a thickness of 0.2 to 5 nm per cm2 per unit area.

According to one embodiment, the separator for the capacitor may have a thickness of 5 to 25 ㎛ or less.

According to another aspect, i) preparing a substrate; ii) forming a ceramic layer on at least one side of the substrate; and iii) forming a graphene layer on the ceramic layer. A method of manufacturing a separator for a capacitor is provided, including.

According to one embodiment, in step ii) a ceramic material; It may include forming a ceramic layer using a dry dispenser supplied with a ceramic layer material including one or more of organic and inorganic binders.

According to one embodiment, step iii) may include forming a graphene layer using a dry dispenser supplied with a graphene layer material containing graphene particles.

According to one embodiment, steps ii) and step iii) may include forming the ceramic layer and the graphene layer on both sides of the substrate.

According to one embodiment, in steps ii) and step iii), the ceramic layer and the graphene layer may include continuously forming the graphene layer after forming the ceramic layer while moving the substrate in a certain direction.

According to one embodiment, the method of manufacturing a separator for a capacitor of the present application may further include iv) a heat treatment step of heating the separator.

According to another aspect, the cathode; anode; A separator for a capacitor described herein provided between the cathode and the anode; and an electrolyte solution in contact with the cathode, anode, and separator. A graphene capacitor including a is provided.

According to one embodiment, the capacitor may be a pseudo supercapacitor, an electric double layer (EDLC) supercapacitor, or a hybrid supercapacitor.

According to one embodiment, the graphene coating separator for a capacitor of the present application forms a graphene layer on a ceramic layer, thereby improving the durability of the separator, activating the electrolyte and anode agent of the capacitor, and maintaining the optimal state of the capacitor. You can extend the life of the capacitor by maintaining it.

According to one embodiment, the method of manufacturing a separator for a capacitor of the present application includes a continuous process including a dry dispensing step, so that the durability of the separator is improved, the electrolyte and anode of the capacitor can be activated, and the optimal capacitor is produced. A graphene-coated separator for a capacitor that can maintain its condition and extend the life of the capacitor can be efficiently manufactured through a simple process.

According to one embodiment, the durability of a graphene capacitor including the graphene coating separator for a capacitor of the present application can be improved, the electrolyte and anode agent are activated, and the optimal capacitor condition is maintained, thereby extending the lifespan.

1 is a cross-sectional view schematically showing a separator for a capacitor according to an embodiment of the present invention.

Figure 2 is a flow chart schematically showing a method of manufacturing a separator for a capacitor according to an embodiment of the present invention.

Figure 3 is a schematic diagram schematically showing a method of manufacturing a separator for a capacitor according to an embodiment of the present invention.

Figure 4 is a diagram schematically showing a supercapacitor according to an embodiment of the present invention.

The objectives, specific advantages and novel features of the present disclosure will become more apparent from the following detailed description and examples taken in conjunction with the accompanying drawings.

Prior to this, terms or words used in this specification and claims should not be construed in their usual, dictionary meaning, and the inventor may appropriately define the concept of the term in order to explain his or her invention in the best way. It must be interpreted with meaning and concept consistent with the technical idea of the present disclosure based on the principle that it is.

In this specification, when a component, such as a layer, part, or substrate, is described as being “on,” “connected to,” or “coupled to” another component, it is directly “on,” or “on” the other component. It may be “connected” or “coupled,” and may have one or more other components interposed between the two components. In contrast, when a component is described as being “directly on,” “directly connected to,” or “directly coupled to” another component, there cannot be any intervening components between the two components. .

The terms used in this specification are merely used to describe specific embodiments and are not intended to limit the present disclosure. Singular expressions include plural expressions unless the context clearly dictates otherwise.

In this specification, terms such as “comprise” or “have” are intended to indicate the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, but are not intended to indicate the presence of one or more other features. It should be understood that this does not exclude in advance the possibility of the existence or addition of elements, numbers, steps, operations, components, parts, or combinations thereof.

In this specification, when a part “includes” a certain component, this means that it may further include other components rather than excluding other components, unless specifically stated to the contrary. In addition, throughout the specification, “on” means located above or below the object part, and does not necessarily mean located above the direction of gravity.

Since the present disclosure can be modified in various ways and can have various embodiments, specific embodiments will be illustrated in the drawings and described in detail in the detailed description. However, this is not intended to limit the present disclosure to specific embodiments, and should be understood to include all transformations, equivalents, and substitutes included in the spirit and technical scope of the present disclosure. In describing the present disclosure, if it is determined that a detailed description of related known technologies may obscure the gist of the present disclosure, the detailed description will be omitted.

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In the description with reference to the accompanying drawings, identical or corresponding components will be assigned the same drawing numbers and duplicate descriptions thereof will be omitted. do.

1 is a cross-sectional view schematically showing a separator for a capacitor according to an embodiment of the present invention.

Referring to FIG. 1, a separator 1 for a capacitor of the present invention according to one aspect includes a substrate 100; A ceramic layer 200 formed on at least one side of the substrate 100; and a graphene layer 300 formed on the ceramic layer 200.

The separator 1 provided between the cathode and anode of the capacitor allows the flow of ionic charges, but serves to prevent electrical contact between the electrodes.

The substrate 100 of the separator 1 is an insulating porous material and is a bare separator. Although not limited thereto, the substrate 100 includes polypropylene (PP), polyethylene (PE), polyimide (PI), polyolefin, polyester, polyacrylonitrile, polyvinylidene fluoride-hexafluoropropylene, etc. A fibrous non-woven fabric or porous glass filter that may include one or more of polymer, cellulose acetate, cellulose acetate butylate, cellulose acetate propionate, polyvinyl butyral, polyvinyl alcohol, polyvinylpyrrolidone, and polyamideimide. It can be.

The substrate 100 of the separator is polyethylene nonwoven fabric, polypropylene nonwoven fabric, polyester nonwoven fabric, polyacrylonitrile porous separator, poly(vinylidene fluoride) hexafluoropropane copolymer porous separator, cellulose porous separator, kraft paper, or rayon. There is no particular limitation as long as it is a separator material commonly used in the battery and capacitor fields, such as fiber.

Although it is not limited to this, the thickness of the substrate 100 is 1 to 20 ㎛, which ensures a smooth flow of ionic charges and has excellent strength and electrical insulation among the physical properties to improve the capacity and lifespan of the capacitor. It may be suitable.

The ceramic layer 200 serves to reinforce electrical properties and mechanical strength between electrodes. Additionally, the ceramic layer 200 can suppress side reactions on the surface of the metal electrode and also suppress the generation of dendrites.

The ceramic layer 200 may be composed of inorganic particles that are various ceramic materials. Although not limited thereto, the ceramic layer 200 may contain metal fluoride, metal oxide, metal nitride, metal carbide, or a combination thereof. At this time, the metals contained in the inorganic particles are Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, Rb, Sr, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, In, Sn, Sb, Cs, Ba, La, Hf, Ta, W, Re, Os, Ir, Pt, Au, Hg, Tl, Pb, Bi, Po, Fr, Ra, Ac, It may be Si, P, As, Se or Te. The inorganic particles may be nano-inorganic particles with a diameter of nanometers. As an example, the inorganic particles may be a metal oxide that exhibits insulating properties, such as aluminum oxide.

Although it is not limited to this, the ceramic layer 200 is composed of spherical alumina particles, which can be stably fused to the substrate 100 compared to plate-shaped alumina particles, and provides smooth charge transfer and stable coating of the graphene layer 300. It may be suitable for.

The ceramic layer 200 has a thickness of 10 to 200 nm so that it can be stably fused to the substrate 100 and is suitable for smooth ion movement and stable coating of the graphene layer 300, and has a thickness of 20 to 170 nm. It may be more suitable.

The ceramic layer 200 may further include a binder that binds the inorganic particles together with the inorganic particles. The binder in the ceramic layer 200 is polyacrylic acid (PAA), polyvinylidene fluoride (PVDF), polyvinylidene fluoride-co-hexafluoropropylene (PVDF-co-HFP), chitosan, polyethylene glycol, and xanthan. It may include gum, gum arabic, polyacrylonitrile (PAN), poly(3,4-ethylenedioxythiophene) (PEDOT), polystyrene sulfonate (PSS), PEDOT:PSS, or mixtures thereof. The binder may be located only in the area between the inorganic particles and serve to bind them together. Specifically, the weight ratio of the inorganic particles and binder in the ceramic layer 200 may be within the range of 2:1 to 8:1.

Additionally, the ceramic layer 200 may have multiple nanometer-sized pores. Although not limited thereto, the pore size of the substrate 100 may be 0.01 to 5 ㎛. According to the above configuration, the flow of ions can be facilitated while maintaining electrical insulation.

The graphene layer 300 includes graphene particles. Graphene is a thin film with a thickness of only 0.2 nm per atom, in which carbon atoms are arranged in a honeycomb shape in which hexagons are laid out tightly. Graphene has the same bonding structure as it has the thickness of one atom layer, but is composed of multiple layers. It is a material that exhibits significantly different characteristics from existing graphite and surpasses carbon nanotubes with excellent properties. In particular, when comparing graphene with carbon nanotubes (CNT), both materials have excellent electrical and mechanical properties, but CNT shows conductor and semiconductor characteristics, while graphene shows conductor characteristics. Compared to CNTs, graphene, which has a flat structure, is advantageous for large areas and applications in electronic processes. Using these characteristics of graphene, it can be usefully applied to energy storage devices.

The graphene layer 300 can improve the electrical conductivity of the electrode and also reduce current density. As a result, in addition to improving the electrochemical reaction efficiency of the electrode active material, it is possible to prevent destruction of the electrode active material or subsequent performance degradation.

The average thickness per cm2 per unit area of the graphene particles in the graphene layer 300 may be 0.2 to 20 nm, specifically 0.2 to 10 nm, more specifically 0.2 to 5 nm, and more specifically 0.35 to 5 nm. there is. Additionally, the average width of the graphene particles may be 0.1 to 20 ㎛, specifically 1 to 15 ㎛, and more specifically 7 to 13 ㎛. In addition, the graphene particle may have one or several atomic layers, and as an example, about 1 to 100 atomic layers, more specifically 1 to 50 atomic layers, more specifically 1 to 25 atomic layers, More specifically, it may have 1 to 10 atomic layers, more specifically 1 to 5 atomic layers, and more specifically 1 to 3 atomic layers.

Inorganic particles such as silicon particles included in the conventional ceramic layer 200 may crack due to large volume expansion and contraction during charging and discharging, which may have the disadvantage of greatly reducing electrical continuity. In addition, an electrolyte layer is created on the surface of the damaged particle, and as charging and discharging continues, the layer becomes thicker, which can be a problem in that capacitor capacity and lifespan are greatly reduced. In order to solve this problem, we attempted to solve this problem by forming a graphene layer 300 on the surface of the ceramic layer 200.

The separator 1 including the graphene layer 300 can maintain a charge/discharge speed superior to that of an existing hybrid capacitor and distribute charges evenly due to the electrical characteristics of the graphene mesh. Therefore, it is possible to prevent activation of the electrolyte and positive electrode agent from being inhibited by uneven temperature distribution and uneven electrode distribution due to conventional uneven charge distribution.

Therefore, according to the above configuration, the problems caused by the conventional ceramic layer 200 described above can be solved, the durability of the separator 1 can be further improved, the electrolyte and anode of the capacitor can be activated, and optimal By maintaining the condition of the capacitor, the lifespan of the capacitor can be extended.

Furthermore, the graphene layer 300 may further include one or more types of carbon particles such as carbon nanotubes, acetylene black, Super-P, Ketjen black, activated carbon, etc.

Additionally, the graphene layer 300 may further include a binder. The binder in the graphene layer 300 is polyacrylic acid (PAA), polyvinylidene fluoride (PVDF), polyvinylidene fluoride-co-hexafluoropropylene (PVDF-co-HFP), chitosan, polyethylene glycol, and xanthan. It may include gum, gum arabic, polyacrylonitrile (PAN), poly(3,4-ethylenedioxythiophene) (PEDOT), polystyrene sulfonate (PSS), PEDOT:PSS, or mixtures thereof. As an example, the binder in the graphene layer 300 may be PVDF. Additionally, the binder in the graphene layer 300 may further include, for example, graphite powder, which is a conductive adhesive. It may be appropriate to include 1 to 50 parts by weight of the graphite powder per 100 parts by weight of the binder. According to the above configuration, the graphene layer 300 is stably fused to the ceramic layer 200, the durability of the separator 1 can be further improved, the electrolyte and anode of the capacitor can be activated, and the optimal By maintaining the condition of the capacitor, the lifespan of the capacitor can be extended. For example, the graphite powder may be Everyohm 30CE (Nippon Graphite Industries, Ltd.).

Although not limited to this, the ceramic layer 200 and the graphene layer 300 may be formed on both sides of the substrate 100. According to the above configuration, the problems caused by the conventional ceramic layer described above can be solved, the durability of the separator 1 can be further improved, the electrolyte and anode agent of the capacitor can be activated, and the optimal state of the capacitor can be maintained. This can further help extend the life of the capacitor.

Although not limited thereto, the separator 1 for a capacitor may have a thickness of 1 to 25 ㎛, specifically 5 to 25 ㎛, and more specifically 10 to 25 ㎛. According to the above configuration, the capacity and lifespan of the capacitor can be improved while optimizing the function of the separator.

Hereinafter, a method of manufacturing the separator 1 for a capacitor according to an embodiment of the present invention will be described. Here, overlapping descriptions of the capacitor separator 1 discussed above may be omitted or simplified.

Figure 2 is a flow chart schematically showing a method of manufacturing a separator for a capacitor according to an embodiment of the present invention. Figure 3 is a schematic diagram schematically showing a method of manufacturing a separator for a capacitor according to an embodiment of the present invention.

Referring to Figures 2 and 3, a method of manufacturing a separator for a capacitor according to another aspect includes the steps of i) preparing a substrate 100 (S10); ii) forming a ceramic layer 200 on at least one side of the substrate 100 (S20); and iii) forming a graphene layer 300 on the ceramic layer 200 (S30).

Step i) is a step (S10) of preparing the substrate 100, which is a bare separator. The substrate 100 may be prepared as an insulating porous material. Although not limited thereto, the substrate 100 may be formed to have a thickness of 1 to 20 ㎛. According to the above configuration, smooth movement of charges can be ensured and the capacity and lifespan of the capacitor can be improved.

Step ii) is a step (S20) of forming a ceramic layer 200 on at least one side of the substrate 100. The ceramic layer 200 may be formed by various known methods, such as blade coating or spray coating. Although it is not limited to this, it may be appropriate for the ceramic layer 200 to be formed using dry dispensing in terms of improving process efficiency. i.e. ceramic material in step ii); The ceramic layer 200 may be formed using the dry first dispenser 400 supplied with a ceramic layer 200 material containing at least one type of organic and inorganic binder. At this time, the ceramic layer 200 may be formed on the substrate 100 due to electrostatic attraction.

Inorganic particles, which are the material of the ceramic layer 200, and at least one type of organic and inorganic binder that binds the inorganic particles and helps fusion to the substrate 100 are mixed in a certain ratio, and the first dispenser 400 ) can be supplied to.

As described above, the ceramic layer 200 material is stably fused to the substrate 100 by the dry first dispenser 400 supplied with the ceramic layer 200 material containing at least one type of organic and inorganic binder. It can be done, and the continuous process can be simple and efficient compared to the wet process using slurry.

Although it is not limited to this, if the ceramic layer 200 is composed of spherical alumina particles, fluidity can be secured during internal movement and spraying in the first dispenser 400 compared to plate-shaped alumina particles, and the substrate 100 It can be stably fused to and can be suitable for smooth charge transfer and stable coating of the graphene layer 300.

Although not limited thereto, the ceramic layer 200 formed to a thickness of 10 to 200 nm can be stably fused to the substrate 100 and is suitable for smooth charge transfer and stable coating of the graphene layer 300. and 20 to 170 nm may be more suitable.

Step iii) is a step (S30) of forming a graphene layer 300 on the ceramic layer 200. Step iii) may include forming the graphene layer 300 using a dry second dispenser 500 supplied with a graphene layer 300 material including graphene particles and a binder.

Graphene particles, which are the material of the graphene layer 300, and at least one type of organic and inorganic binder that binds the graphene particles and helps fusion to the ceramic layer 200 are mixed in a certain ratio, and the second dispenser Supplied to (500).

As described above, the graphene layer 300 material containing at least one type of organic and inorganic binder can be stably fused to the ceramic layer 200 by the dry second dispenser 500 supplied, and can be stably fused to the ceramic layer 200 using a slurry. Compared to wet processes, continuous processes can be simple and efficient.

Step ii) and step iii) may include forming the ceramic layer 200 and the graphene layer 300 on both sides of the substrate 100.

Referring to FIG. 3, in steps ii) and iii), the ceramic layer 200 and the graphene layer 300 are formed by moving the substrate 100 in a certain direction and forming the ceramic layer 200. It may include continuously forming the fin layer 300. According to the above configuration, the separator 1 for a capacitor can be efficiently manufactured through a batch continuous process.

The method of manufacturing a separator for a capacitor of the present application may further include iv) a heat treatment step of heating the separator. Although limited thereto, the heat treatment may be performed at a temperature of 50 to 130° C. for 1 to 10 hours. According to the heat treatment under the above conditions, the ceramic layer 200 and the graphene layer 300 can be stably fixed by the binder, and the mechanical and electrical properties of the separator can be excellent.

Figure 4 is a diagram schematically showing a capacitor including a separator according to an embodiment of the present invention.

Referring to FIG. 4, a graphene capacitor 1000 according to another aspect includes a cathode 1100; anode (1200); A separator 1 for a capacitor described herein provided between the cathode 1100 and the anode 1200; and an electrolyte solution (not shown) in contact with the cathode 1100, the anode 1200, and the separator 1.

The graphene capacitor 1000 of the present application refers to a capacitor in which a graphene layer 300, which is a graphene coating layer, is formed on a separator 1.

The capacitor may be a pseudo supercapacitor, an electric double layer (EDLC) supercapacitor, or a hybrid supercapacitor.

The supercapacitor may be a coin-type, cylindrical, or square-type supercapacitor.

Supercapacitors are energy storage devices that can be used as auxiliary batteries or as replacements for batteries due to their excellent output characteristics, long lifespan, low maintenance costs, rapid output response characteristics, and excellent stability.

The hybrid capacitor may be a lithium ion capacitor.

Supercapacitors can use an asymmetric electrode structure. For example, the cathode 1100 may be a carbon-based electrode with high energy density, and the anode 1200 may be a lithium or sodium transition metal oxide-based electrode with high output and long lifespan.

The negative electrode 1100 may be formed by mixing a negative electrode active material, a binder, a conductive material, and a dispersion medium into various forms.

It may be appropriate to add the negative electrode material in an amount of 2 to 20 parts by weight of the conductive material and 2 to 10 parts by weight of the binder based on 100 parts by weight of activated carbon. The content of the dispersion medium is not particularly limited, but may be added in an amount of 200 to 300 parts by weight based on 100 parts by weight of activated carbon.

In the negative electrode 1100, the negative electrode active material may be a mixture of one or more of activated carbon, soft carbon, hard carbon, and graphite.

The activated carbon is not particularly limited, and activated carbon used in general electrode production can be used. For example, coconut shell-based carbonized activated carbon, phenol resin-based carbonized activated carbon, etc. can be used, and this includes partially crystalline activated carbon. The specific surface area of the activated carbon powder used is preferably 300 to 2500 m2/g. It may be appropriate for the activated carbon powder to have a particle size in the range of 0.9 to 20 ㎛ to facilitate electrode forming and dispersion.

The conductive material is not particularly limited as long as it is an electronically conductive material that does not cause chemical changes. Examples include natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, Super-P, Denka black, carbon fiber, and copper. , metal powders such as nickel, aluminum, and silver, or metal fibers, etc. are possible.

In addition, the binder is polytetrafluoroethylene (PTFE), polyvinylidenefloride (PVdF), carboxymethylcellulose (CMC), polyvinyl alcohol (PVA), and polyvinyl butyral. (poly vinyl butyral; PVB), poly-N-vinylpyrrolidone (PVP), styrene butadiene rubber (SBR), polyamide-imide, polyimide One type or two or more types selected from the like may be used in combination.

The dispersion medium may be an organic solvent such as ethanol (EtOH), acetone, isopropyl alcohol, methyl pyrrolidone (NMP), propylene glycol, or water.

The positive electrode 1200 may be formed in various forms by mixing a positive electrode active material containing lithium or sodium transition metal oxide and activated carbon, a binder, a conductive material, and a dispersion medium.

The cathode material includes 100 parts by weight of the cathode active material, 2 to 15 parts by weight of a conductive material per 100 parts by weight of the cathode active material, and 2 to 10 parts by weight of a binder per 100 parts by weight of the cathode active material, and the dispersion medium is 100 parts by weight of the cathode active material. It may be appropriate to manufacture it at 200 to 300 parts by weight.

The lithium transition metal oxide may be a composite metal oxide having a layered structure, spinel structure, or olivine structure containing lithium and a transition metal. The transition metal may be at least one metal selected from the group consisting of titanium (Ti), vanadium (V), manganese (Mn), iron (Fe), cobalt (Co), aluminum (Al), and nickel (Ni). . These lithium transition metal oxides include LiMn ₂ 0 ₄ , LiCoO ₂ , LiNi1/3Co1/3Mn1/3O ₂ , Examples include LiNixCoxAlxO ₂ and the like. The specific surface area of the lithium transition metal oxide may be suitably in the range of 0.1 to 100 m2/g.

When only lithium transition metal oxide is used as the positive electrode active material, the positive electrode develops capacity through a mechanism using chemical reactions, resulting in output asymmetry with the negative electrode. In other words, a chemical reaction occurs in the anode using lithium transition metal oxide and a physical reaction occurs in the cathode using activated carbon, resulting in output asymmetry between the anode and the cathode. Therefore, the voltage shock is relatively applied to the carbon electrode, which is the cathode, which limits the use of the hybrid ion capacitor at high output and high voltage, and may cause reliability problems.

In order to improve the withstand voltage characteristics and output characteristics of a hybrid ion capacitor cell by suppressing the above-described output asymmetry and improving cell capacity, activated carbon is used as a positive electrode active material along with lithium transition metal oxide. Activated carbon powder used as a positive electrode active material may be coconut shell-based activated carbon, phenol resin-based activated carbon, coke-based activated carbon, or a mixture thereof, and it may be appropriate to use activated carbon powder having a specific surface area of 1,000 to 2,500 ㎡/g.

The activated carbon powder used as a positive electrode active material may be appropriately contained in an amount of 1 to 30 parts by weight based on 100 parts by weight of the positive electrode active material. If the content of activated carbon powder used as a cathode active material is less than 1 part by weight, the effect of suppressing output asymmetry is weak, and if it exceeds 30 parts by weight, the effect of suppressing output asymmetry can no longer be expected, and the energy density of activated carbon is low due to lithium transfer. Because it is insufficient compared to metal oxide, a significant portion of the efficiency of the hybrid system is lost due to capacity reduction. Therefore, the weight ratio of lithium transition metal oxide and activated carbon powder (lithium transition metal oxide: activated carbon powder) in the positive electrode active material is preferably in the range of 99:1 to 70:30.

Instead of lithium, the cathode active material can contain sodium, which is abundant in resources but inexpensive.

The conductive material is not particularly limited as long as it is an electronically conductive material that does not cause chemical changes. Examples include natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, Super-P, Denka black, carbon fiber, and copper. , metal powders such as nickel, aluminum, and silver, or metal fibers, etc. are possible.

The binder is polytetrafluoroethylene (PTFE), polyvinylidenefloride (PVdF), carboxymethylcellulose (CMC), polyvinyl alcohol (PVA), and polyvinyl butyral (polyvinyl butyral). From vinyl butyral (PVB), poly-N-vinylpyrrolidone (PVP), styrene butadiene rubber (SBR), polyamide-imide, polyimide, etc. One selected type or a mixture of two or more types can be used.

The dispersion medium may be an organic solvent such as ethanol (EtOH), acetone, isopropyl alcohol, methyl pyrrolidone (NMP), propylene glycol (PG), or water.

The electrolyte solution (not shown) may include an organic solvent and lithium salt. The above organic solvent and lithium salt can be used as conventional solvents.

A hybrid supercapacitor cell can be formed by injecting an electrolyte solution containing a dissolved lithium salt to impregnate the electrode structure and sealing it. The lithium salt is a lithium salt commonly used in capacitors and is not particularly limited, for example, LiPF ₆ , LiBF ₄ , LiClO ₄ , Li(CF ₃ SO ₂ ) ₂ , LiCF ₃ SO ₃ , LiSbF ₆ or LiAsF ₆ etc. can be used.

The solvent constituting the electrolyte solution is not particularly limited, but cyclic carbonate-based solvents, linear carbonate-based solvents, ester-based solvents, ether-based solvents, nitrile-based solvents, amide-based solvents, etc. can be used. Ethylene carbonate, propylene carbonate, butylene carbonate, vinylene carbonate, etc. can be used as the cyclic carbonate-based solvent, and dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate, etc. can be used as the linear carbonate-based solvent. Ester-based solvents include methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, and γ-butyrolactone, and ether-based solvents include 1,2-dimethoxyethane and 1,2-diethane. Toxyethane, tetrahydrofuran, 1,2-dioxane, 2-methyltetrahydrofuran, etc. can be used. The nitrile-based solvent can be used such as acetonitrile, and the amide-based solvent can be used such as dimethylformamide. can be used.

Carbon materials are used as electrode materials for supercapacitors. Graphene is a nanocarbon material that has a high specific surface area and excellent electrical conductivity, making it a very suitable material for application in supercapacitors as it has excellent compatibility with existing carbon-based electrode materials. can do.

Example

Example 1

(1) Manufacture of separator for supercapacitor:

A porous membrane substrate of polypropylene was prepared.

As a ceramic layer material, 45 mg of spherical Al ₂ O ₃ nanopowder (Aldrich, USA) and 11.3 mg of polyvinylidene fluoride (PVDF, Arkema) (mass ratio approximately 4:1) were added to 15 ml of acetone and sonicated for 2 hours. Al ₂ O ₃ slurry was obtained by mixing through mixing, which was then powdered and supplied to the first dispenser.

As a graphene layer material, 45 mg of graphene (thickness 1.6 nm) and 11.3 mg of polyvinylidene fluoride (PVDF, Arkema) (mass ratio approximately 4:1) were added to 15 ml of acetone and mixed through sonication for 2 hours to form graphene. After obtaining the slurry, it was powdered and supplied to the second dispenser.

While moving the substrate in a certain direction using a conveyor belt, a ceramic layer material was sprayed through the spray nozzles of the first dispenser provided on both sides of the substrate to form a ceramic layer on the surface of the substrate.

A separator for a capacitor was manufactured by spraying a graphene layer material on the surface on which the ceramic layer was formed through the spray nozzles of a second dispenser located on both sides of the substrate and behind the first dispenser to form a graphene layer on the surface of the ceramic layer. .

(2) Supercapacitor manufacturing: prepare a positive electrode (carbon-based material, 90% by weight or more of active material) and a negative electrode (graphite electrode formed on a porous Cu current collector), and the manufactured After placing the separator inside the case, the inside of the case is filled with an electrolyte (including LiPF ₆ at a concentration of 1M), and the electrolyte is brought into contact with the anode, cathode, and separator to form a supercapacitor (lithium ion capacitor, cell type: coin cell) 2032) was manufactured.

Although the present disclosure has been described in detail through specific examples, this is for the purpose of specifically explaining the present disclosure, and the present disclosure is not limited thereto, and may be understood by those skilled in the art within the technical spirit of the present disclosure. It is clear that modifications and improvements are possible. All simple modifications or changes to the present disclosure fall within the scope of the present disclosure, and the specific scope of protection of the present disclosure will be made clear by the appended claims.

[Explanation of symbols]

1: Separator

100: Listed

200: Ceramic layer

300: Graphene layer

400: First dispenser

500: Second dispenser

1000: Supercapacitor

1100: cathode

1200: anode

Claims (14)

1. write;

   a ceramic layer formed on at least one side of the substrate; and

   A separator for a capacitor comprising; a graphene layer formed on the ceramic layer.
2. According to paragraph 1,

   A separator for a capacitor, wherein the ceramic layer and the graphene layer are formed on both sides of the substrate.
3. According to paragraph 1,

   A separator for a capacitor, wherein the ceramic layer includes spherical alumina particles.
4. According to paragraph 1,

   A separator for a capacitor, wherein the ceramic layer and the graphene layer further include one or more types of organic and inorganic binders.
5. According to paragraph 1,

   The graphene layer is a separator for a capacitor having a thickness of 0.2 to 5 nm per cm2 per unit area.
6. According to paragraph 1,

   The separator for a capacitor has a thickness of 5 to 25 ㎛.
7. i) preparing the substrate;

   ii) forming a ceramic layer on at least one side of the substrate; and

   iii) forming a graphene layer on the ceramic layer.
8. In clause 7,

   Ceramic in step ii); A method of manufacturing a separator for a capacitor, comprising forming a ceramic layer using a dry dispenser supplied with a ceramic layer material containing; and at least one type of organic and inorganic binder.
9. In clause 7,

   A method of manufacturing a separator for a capacitor, comprising forming a graphene layer using a dry dispenser supplied with a graphene layer material containing graphene particles in step iii).
10. In clause 7,

    In step ii) and step iii), the ceramic layer and the graphene layer are formed on both sides of the substrate.
11. In clause 7,

    In step ii) and step iii), the ceramic layer and the graphene layer are formed continuously after forming the ceramic layer while moving the substrate in a certain direction.
12. In clause 7,

    iv) a heat treatment step of heating the separator; a method of manufacturing a separator for a capacitor, further comprising:
13. cathode;

    anode;

    A separator for the capacitor according to claim 1 provided between the cathode and the anode; and

    A graphene capacitor comprising: an electrolyte in contact with the cathode, anode, and separator.
14. According to clause 13,

    The capacitor is a graphene capacitor, which is a pseudo supercapacitor, an electric double layer (EDLC) supercapacitor, or a hybrid supercapacitor.

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