WO2018184555A1 - Activated carbon microbead, electrode, and supercapacitor - Google Patents

Abstract

Provided are an electrode using graphene as an electrically-conductive agent and a supercapacitor. An electrode of the supercapacitor comprises an electrode current collector and an electrode active material layer at the electrode current collector. The electrode active material layer at least comprises an electrode active material and an electrically-conductive agent. The electrically-conductive agent comprises graphene.

Description

Activated carbon microspheres, electrodes and supercapacitors Technical field

The invention relates to electrodes. In particular, the present invention relates to an electrode which can be used for an ultracapacitor, an ultracapacitor including the electrode, and an electric device using the activated carbon microsphere as an electrode active material.

Background technique

A supercapacitor is an electrochemical energy storage device between a conventional capacitor and a battery. It has higher capacitance than conventional capacitors; it has higher power density and longer cycle life than batteries.

Supercapacitors have many significant advantages, such as high power density, short charge and discharge times, theoretically unlimited in cycle life, wide operating temperature range, and instant high current. However, it also has the disadvantages of low energy storage, low energy density, low specific capacitance, large internal resistance, easy destruction of the electrode material structure during charging and discharging, resulting in a decrease in charge and discharge capacity and cycle performance.

Summary of the invention

The present invention has been made in view of the above technical problems in the prior art, and an object thereof is to provide an electrode, a supercapacitor including the same, a circuit including the supercapacitor, and an electric device including the same; In the case of a capacitor, it is possible to increase the energy storage capacity, increase the energy density, increase the specific capacitance, lower the internal resistance, prevent the electrode material structure from being destroyed during charging and discharging, prevent the charge/discharge capacity from being lowered, and/or prevent the cycle performance from deteriorating.

The present inventors have conducted intensive studies to solve the above-described technical problems, and as a result, have found that one or more or all of the above technical problems can be solved by using specific activated carbon microspheres as an electrode active material in an electrode active material layer, thereby The present invention has been completed.

That is, the present invention includes:

An activated carbon microsphere, wherein the activated carbon microspheres have a particle size distribution of 0.5-15 μm, and the activated carbon microspheres having a particle size distribution of 0.5-10 μm account for 10-90%, and the particle size distribution is 5- The 15 μm activated carbon microspheres accounted for 90-10%.

2. The activated carbon microsphere according to Item 1, wherein the activated carbon microspheres have an average particle diameter D10 of 0.5 to 5 μm and a D50 of 7 to 10 μm, preferably D10 of 1 to 4 μm, more preferably 2-3 μm, preferably D50. It is 7-9 μm, more preferably 7.5-8.5 μm.

3. The activated carbon microsphere according to Item 1 or 2, wherein the activated carbon microspheres having a particle size distribution of 0.5 to 10 μm account for 20 to 80%, preferably 30 to 70%, more preferably 40 to 60%, more preferably 45-55%; activated carbon microspheres having a particle size distribution of 5-15 μm accounted for 80-20%, preferably 70-30%, more preferably 60-40%, still more preferably 55-45%.

The activated carbon microsphere according to any one of items 1 to 3, wherein the activated carbon microspheres have a bulk density of 0.5 to 1.5 g/cm ³ , preferably 0.5 to 1.2 g/cm ³ , more preferably 0.6 to 0.9g/cm ³ .

A method for producing activated carbon microspheres, comprising the steps of:

Step A: Prepare a carbon source;

Step B: hydrothermally reacting the carbon source to obtain primary carbon microspheres;

Step C: The primary carbon microspheres are subjected to a carbonization reaction and an activation reaction to obtain activated carbon microspheres.

6. The production method according to item 5, wherein the carbon source is glucose, xylose or cellulose.

7. The production method according to item 5 or 6, wherein the carbon source is at a concentration of from 1 to 99% by weight, preferably from 3 to 70% by weight, more preferably from 5 to 60% by weight, still more preferably from 7 to 50% by weight. More preferably, it is 10-40% by weight of an aqueous glucose solution.

8. The manufacturing method according to item 7, wherein the glucose is derived from corn starch hydrolysis.

The production method according to any one of items 5 to 8, wherein the hydrothermal reaction has a reaction temperature of 120 to 180 °C.

The production method according to any one of items 5 to 9, wherein the reaction time of the hydrothermal reaction is 3 to 6 hours.

The production method according to any one of items 5 to 10, wherein a catalyst is used in the hydrothermal reaction, the catalyst is selected from the group consisting of: hydroxyl-cage phosphates and derivatives thereof, formation of weak acids and alkali metals Salts and acids (generally inorganic acids).

The production method according to any one of items 5 to 11, wherein a weight ratio of the carbon source (in terms of carbon) to the catalyst is from 1:1 to 10:1, preferably from 2:1 to 1-6. 1: more preferably 3:1 to 4:1.

The method of producing the activated carbon microsphere according to any one of items 19 to 22, wherein the method of producing the activated carbon microsphere according to any one of items 19 to 22.

An electrode comprising an electrode current collector and an electrode active material layer present on the electrode current collector, the electrode active material layer comprising at least activated carbon microspheres as an electrode active material; wherein the activated carbon microspheres are The activated carbon microsphere according to any one of items 1 to 4, wherein the production method according to any one of items 5 to 13 is used.

15. The electrode of clause 14, wherein the electrode is a positive electrode.

16. The electrode of clause 14, wherein the electrode is a negative electrode.

The electrode according to any one of items 14 to 16, wherein the electrode is used for a supercapacitor.

A supercapacitor comprising a positive electrode, a negative electrode, a separator, and an electrolyte, wherein any one or all of the positive electrode and the negative electrode are the electrode according to any one of items 14-17.

19. A circuit comprising the ultracapacitor of item 18.

20. An electrical device comprising the circuit of item 19.

DRAWINGS

Figure 1 is a SEM photograph of the activated carbon microspheres obtained in Example 6.

Fig. 2 is a pore volume-aperture distribution diagram of the activated carbon microspheres obtained in Example 6.

Figure 3 is a graph showing the BET specific surface area of the activated carbon microspheres obtained in Example 6.

Figure 4 is a SEM photograph of the activated carbon microspheres obtained in Example 9.

Fig. 5 is a pore volume-aperture distribution diagram of the activated carbon microspheres obtained in Example 9.

Figure 6 is a graph showing the BET specific surface area of the activated carbon microspheres obtained in Example 9.

detailed description

In order to more clearly clarify the objects, technical solutions, and technical effects of the present invention, the specific embodiments of the present invention will be described with reference to the accompanying drawings. It should be understood that the described embodiments are only some, but not all, of the embodiments.

Activated carbon microsphere

In one aspect of the present invention, there is provided an activated carbon microsphere (the activated carbon microsphere of the present invention) having a particle size distribution of 0.5-15 μm and an activated carbon microparticle having a particle size distribution of 0.5-10 μm. The proportion of balls is 10-90%, and the proportion of activated carbon microspheres with a particle size distribution of 5-15 μm is 90-10%.

The above particle size distribution can be detected by the specific method given in the examples. First, the agglomerated adhesion microspheres are dispersed by a high-efficiency disperser, and then the dispersed activated carbon microspheres are photographed by SEM electron microscopy, according to the SEM photograph. The microspheres were counted and counted by the naked eye and according to the scale given in the photograph, and the number of microspheres with particle size distribution of 0.5-10 μm was calculated according to the counting result. Percentage of carbon microspheres, activated carbon microspheres with a particle size distribution of 5-15 μm accounted for the percentage of all carbon microspheres.

The activated carbon microspheres have an average particle diameter D10 of 0.5 to 5 μm and a D50 of 7 to 10 μm. Wherein D10 refers to the particle size corresponding to the cumulative particle size distribution of a sample of 10%. Its physical meaning is that the particle size is less than 10% of its total particle size. Similarly, D50 refers to the particle size corresponding to the cumulative particle size distribution of a sample reaching 50%. Its physical meaning is that the particle size is less than 50% of its total particle size. The particle size distribution can be detected by a conventional instrument used by those skilled in the art, for example, by using a laser particle size distribution analyzer Bettersize 2000 LD, using carbon as a reference, dispersing the aqueous medium, and then detecting.

In the activated carbon microsphere of the present invention, the activated carbon microspheres having a particle size distribution of 0.5 to 10 μm account for 20 to 80%, preferably 25 to 75%, more preferably 30 to 70%, still more preferably 35 to 65%, still more preferably 40. -60%, more preferably 45-55%; activated carbon microspheres having a particle size distribution of 5-15 μm accounted for 80-20%, preferably 70-30%, more preferably 60-40%, more preferably 55-45%. The particle size distribution can be determined using, for example, a laser particle size distribution meter. The activated carbon microspheres of the present invention may have a bulk density of from 0.5 to 1.5 g/cm ³ .

In general, the thickness of the active material layer on the electrode has a certain range. Under the condition of a certain thickness, if the bulk density of the electrode activity is larger, the energy density of the electrode is higher and the energy storage is more, and the electrode is super. The higher the volumetric capacity of the capacitor, the better the performance.

The present inventors have found that when the activated carbon microsphere as the electrode active material satisfies the above conditions, it can be made to have a larger bulk density, thereby making it possible to use a supercapacitor having an electrode having the activated carbon microsphere as an electrode active material. Performance is improved.

Further, the inventors have found that the activated carbon microspheres of the present invention can be easily produced by the following production method. Accordingly, in another aspect, the present invention also provides a method of producing activated carbon microspheres (manufacturing method of the present invention) comprising the steps of:

Step A: Prepare a carbon source;

Step B: hydrothermally reacting the carbon source to obtain primary carbon microspheres;

Step C: The primary carbon microspheres are subjected to a carbonization reaction and an activation reaction to obtain activated carbon microspheres.

Here, the carbon source may be any organic substance such as glucose, xylose or cellulose.

Preferably, the carbon source may be a glucose aqueous solution having a concentration of 1 to 99% by weight, preferably 3 to 70% by weight, more preferably 5 to 60% by weight, more preferably 7 to 50% by weight, still more preferably 10 to 40% by weight. .

The glucose is derived from the hydrolysis of corn starch. The corn starch is a corn processing product, which utilizes corn starch hydrolysis to produce glucose, uses the glucose as a carbon source to manufacture activated carbon microspheres, and finally manufactures electrodes and supercapacitors, which can provide a solution to the problem of excessive corn reserves existing in China. An effective way.

The reaction temperature of the hydrothermal reaction may be, for example, 105 to 300 ° C, 110 to 240 ° C, 120 to 220 ° C, 130 to 200 ° C, 135 to 190 ° C, and 140 to 180 ° C.

The reaction time of the hydrothermal reaction may be, for example, 0.5 to 50 hours, 1 to 20 hours, 1.5 to 15 hours, 2 to 10 hours, 3 to 6 hours.

A catalyst may be used in the hydrothermal reaction, and the catalyst may be selected from the group consisting of hydroxyl cage phosphates and derivatives thereof, specifically, for example, pentaerythritol cage phosphate, bicyclic cage phosphate, etc.; weak acid and base The salts formed by the metal are, for example, sodium acetate, sodium carbonate, potassium carbonate; and acids (generally inorganic acids), specifically, for example, a mixture of phosphoric acid, acetic acid, boric acid, and dilute sulfuric acid. Preferably, the catalyst has good carbon properties, excellent thermal stability, and a rich carbon source. Wherein, the weight ratio of the carbon source (in terms of carbon) to the catalyst may be from 1:1 to 10:1, preferably from 2:1 to 6:1, more preferably from 3:1 to 4:1. The inventors have found that the particle size distribution of the activated activated carbon microspheres can be controlled by adjusting the weight ratio of the carbon source to the catalyst.

After the hydrothermal reaction, primary carbon microspheres are obtained, and the primary carbon microspheres are subjected to a carbonization reaction and an activation reaction to obtain activated carbon microspheres. Here, the carbonization reaction can be carried out at a carbonization temperature of 300 to 600 ° C, preferably 350 to 500 ° C, further preferably 350 to 450 ° C, and a carbonization time of 20 to 60 min, preferably 25 to 55 min, further preferably 30 to 50 min. The activation reaction can be carried out at an activation temperature of 600 to 1000 ° C, preferably 600 to 900 ° C, further preferably 700 to 800 ° C, and an activation time of 30 to 120 min, preferably 30 to 90 min, further preferably 45 to 80 min.

In the present invention, since a selected catalyst is employed in the hydrothermal reaction, it is possible to obtain a given particle diameter and particle diameter by controlling a given ratio of the catalyst to the carbon source, and selecting the time and temperature of the hydrothermal reaction. Distributed carbon microspheres. In the prior art, only a simple hydrothermal reaction is used, and no catalyst is used, which requires high temperature, high pressure, and long time, which are unfavorable for industrial production, and we use a special simple and readily available catalyst to control the catalyst and carbon source. The ratio is reacted to lower the reaction temperature, shorten the reaction time, and greatly reduce the production cost, thereby facilitating industrial production. And the desired carbon microspheres having a given particle size and particle size distribution of the present invention can be obtained by the preparation method of the present invention.

2. Electrode

In one aspect of the invention, an electrode (electrode of the invention) is provided. The electrode of the present invention comprises an electrode current collector and an electrode active material layer present on the electrode current collector, the electrode active material layer comprising at least activated carbon microspheres as an electrode active material; wherein the activated carbon microspheres are item 1 to The activated carbon microsphere of the present invention according to any one of 4, or the activated carbon microsphere produced by the production method of the present invention.

Preferably, the electrode active material layer may further contain a conductive agent, and the conductive agent contains graphene.

2-1. Electrode active material

The electrode active material may be a positive electrode active material or a negative electrode active material, and is not particularly limited, and a positive electrode active material and a negative electrode active material which are generally used in the art can be used.

Preferably, the electrode active material has the activated carbon microspheres of the present invention as a main component, that is, among all the electrode active materials, the weight ratio of the activated carbon microspheres of the present invention is 10% or more, 20% or more, 30% or more. 40% or more, 50% or more, 60% or more, 70% or more, 80% or more, 85% or more, 90% or more, 95% or more, 97% or more, 99% or more, or 100%.

The electrode active material layer may further contain other electrode active materials in addition to the activated carbon microspheres of the present invention. Hereinafter, other electrode active materials will be described.

For example, as the positive electrode active material, for example, a substance containing lithium and at least one transition metal may be used. Specific examples include a lithium transition metal composite oxide and a lithium-containing transition metal phosphate compound. The transition metal of the lithium transition metal composite oxide is preferably V, Ti, Cr, Mn, Fe, Co, Ni, Cu, etc., and specific examples thereof include lithium-cobalt composite oxide such as LiCoO ₂ and lithium such as LiNiO ₂ . a lithium-manganese composite oxide such as a nickel composite oxide, LiMnO ₂ , LiMn ₂ O ₄ or Li ₂ MnO _{4 ,} or a part of a transition metal atom as a main component of these lithium transition metal composite oxides, Na, K, B, F, A composite oxide obtained by replacing other elements such as Al, Ti, V, Cr, Mn, Fe, Co, Li, Ni, Cu, Zn, Mg, Ga, Zr, Si, Nb, Mo, Sn, and W. Specific examples of the composite oxide obtained by the substitution include LiNi _0.5 Mn _0.5 O ₂ , LiNi _0.85 Co _0.10 Al _0.05 O ₂ , LiNi _0.33 Co _0.33 Mn _0.33 O ₂ , LiNi _0.45 Co _0.10 Al _0.45 O _{2 .} LiMn _1.8 Al _0.2 O ₄ , LiMn _1.5 Ni _0.5 O ₄ or the like. Examples of the transition metal of the lithium-containing transition metal phosphate compound include V, Ti, Cr, Mn, Fe, Co, Ni, Cu, etc., and specific examples thereof include LiFePO ₄ and Li ₃ Fe ₂ (PO ₄ ) _{3 .} , such as iron phosphate such as LiFeP ₂ O ₇ or cobalt phosphate such as LiCoPO _{4 ,} and a part of the transition metal atom as a main component of these lithium transition metal phosphate compounds is Al, Ti, V, Cr, Mn, Fe, Co, Li, Ni. A compound obtained by replacing other elements such as Cu, Zn, Mg, Ga, Zr, Nb, and Si. These positive electrode active materials may be used alone or in combination of two or more.

Examples of the negative electrode active material include graphite (natural graphite, artificial graphite, etc.) as high crystalline carbon, low crystalline carbon (soft carbon, hard carbon), and carbon black (Ketjen Black (registered trademark), acetylene black). , channel black, lamp black, oil furnace black, thermal black, etc.), fullerenes, carbon nanotubes, carbon nanofibers, carbon nanohorns, carbon filaments and other carbon materials. Further, examples of the negative electrode active material include Si, Ge, Sn, Pb, Al, In, Zn, H, Ca, Sr, Ba, Ru, Rh, Ir, Pd, Pt, Ag, Au, Cd, and Hg. And elements such as Ga, Tl, C, N, Sb, Bi, O, S, Se, Te, Cl, etc., which are alloyed with lithium, oxides and carbides containing these elements. Examples of such an oxide include silicon monoxide (SiO), SiO _x (0<x<2), tin dioxide (SnO ₂ ), SnO _x (0<x<2), and SnSiO ₃ as carbonization. Examples of the material include silicon carbide (SiC) and the like. Further, examples of the negative electrode active material include a metal material such as lithium metal and a lithium-transition metal composite oxide such as a lithium-titanium composite oxide (for example, lithium titanate Li ₄ Ti ₅ O ₁₂ ). However, it is not limited to these materials, and a conventionally known material which can be used as a negative electrode active material for a lithium ion secondary battery can be used. These negative electrode active materials may be used alone or in combination of two or more.

Further, as the positive electrode active material, for example, nickel hydroxide or nickel hydroxide can be oxidized. As the negative electrode active material, for example, a hydrogen absorbing alloy or a metal hydroxide can be used. As other alternatives of the positive electrode or the negative electrode active material, for example, silver, silver cyanide, silver iodide, cobalt, cobalt oxide, cobalt hydroxide, cobalt phosphate, cobalt silicate, copper, copper oxide may also be mentioned. , copper hydroxide, ammonia copper, gallium, gallium oxides, gallium hydroxides, gallium phosphates, gallium silicates, indium, indium oxides, indium hydroxides, indium phosphates, silicic acid Indium, molybdenum, molybdenum oxide, molybdenum hydroxide, molybdenum phosphate, molybdenum silicide, lead, lead oxide, lead hydroxide, lead phosphate, lead silicic acid, Tin, tin oxides, tin hydroxides, tin phosphates, tin silicates, antimony, antimony oxides, antimony hydroxides, antimony phosphates, strontium silicates, vanadium, vanadium oxide Examples, vanadium hydroxides, vanadium phosphates, vanadium silicates, but are not limited thereto.

Further, as the positive electrode active material, for example, nickel oxyhydroxide or nickel hydroxide can be used. As the negative electrode active material, for example, cadmium or cadmium hydroxide can also be used.

Further, as the positive electrode active material, for example, PbO ₂ can also be used. As the negative electrode active material, for example, PbSO ₄ can also be used. Other examples of the positive electrode active material or the negative electrode active material include silver, silver sulfate, mercury, mercury phosphate, mercury sulfate, manganese oxide, barium, strontium oxide, and barium hydroxide. , phosphonium phosphates, strontium silicates, sulfur oxides, sulfurous acid, antimony oxides, selenium, selenium oxides, antimony, antimony oxides, antimony hydroxides, antimony phosphates, antimony silicates Classes, uranium oxides, uranium hydroxides, uranium phosphates, uranium silicates, but are not limited thereto.

Further, as the positive electrode active material, a sodium-containing compound can also be used. Examples of the sodium-containing compound include sodium iron composite oxide (NaFeO ₂ ), sodium cobalt composite oxide (NaCoO ₂ ), sodium chromium composite oxide (NaCrO ₂ ), and sodium manganese as a layered oxide material. Composite oxide (NaMnO ₂ ), sodium nickel composite oxide (NaNiO ₂ ), sodium nickel titanium composite oxide (NaNi _1/2 Ti _1/2 O ₂ ), sodium nickel manganese composite oxide (NaNi _1/2 Mn _{1 /2} O ₂ ), sodium iron manganese composite oxide (Na _2/3 Fe _1/3 Mn _2/3 O ₂ ), sodium nickel cobalt manganese composite oxide (NaNi _1/3 Co _1/3 Mn _1/3 O ₂ ), their solid solution, compounds of non-stoichiometric composition, and the like. Further, examples of the sodium-containing compound include a sodium manganese composite oxide (NaMn ₂ O ₄ ), a sodium nickel manganese composite oxide (NaNi _1/2 Mn _3/2 O ₂ ), and the like. Further, examples of the sodium-containing compound include a sodium iron phosphate compound (NaFePO ₄ ), a sodium manganese phosphate compound (NaMnPO ₄ ), and a sodium cobalt phosphate compound (NaCoPO ₄ ) as an olivine material. Further, examples of the sodium-containing compound include Na ₂ FePO ₄ F, Na ₂ MnPO ₄ F, Na ₂ CoPO ₄ F, and the like, which are fluorinated olivine-based materials. Further, an organic active material such as a polymer radical compound or a π-conjugated polymer may be mentioned. Further, an element which forms a compound with sodium, such as a solid sulfur or a sulfur-carbon composite material, may also be mentioned. However, it is not limited thereto, and other materials such as a sodium-containing transition metal oxide, a sodium-containing transition metal sulfide, and a sodium-containing transition metal fluoride may be used. As the negative electrode active material, for example, high crystalline carbon such as graphite, low crystalline carbon such as soft carbon, hard carbon, carbon black (Ketjen Black, acetylene black, channel black, lamp black, or the like) may be used. Carbon materials such as oil furnace black, thermal black, etc., fullerenes, carbon nanotubes, carbon nanofibers, carbon nanohorns, carbon filaments, polyacene and the like. Further, examples of the other negative electrode active material include Si, Ge, Sn, Pb, In, Zn, H, Ca, Sr, Ba, Ru, Rh, Ir, Pd, Pt, Ag, Au, Cd, and Hg. Elemental elements of elements such as Ga, Tl, C, N, Sb, Bi, O, S, Se, Te, Cl, etc., which are alloyed with sodium, oxides containing these elements (SiO, SiOx, SiOx (0) <x<2), tin dioxide (SnO ₂ ), SnO _x (0<x<2), SnSiO _{3 ,} etc.), and carbide (SiC or the like). In addition, examples of the other negative electrode active material include a metal material such as sodium metal and a sodium-transition metal composite oxide such as a sodium-titanium composite oxide (sodium titanate: Na ₄ Ti ₅ O ₁₂ ). However, it is not limited to these materials. These negative electrode active materials may be used alone or in combination of two or more.

2-2. Current collector

The positive electrode current collector and the negative electrode current collector are made of a conductive material. The size of the current collector can be determined based on the use of the supercapacitor. For example, if used in a large supercapacitor requiring high energy density, a large current collector can be used. There is no particular limitation on the thickness of the current collector. The thickness of the current collector is usually about 0.1 to 1000 μm, preferably about 1 to 100 μm. The shape of the current collector is not particularly limited. There is no particular limitation on the materials constituting the current collector. For example, a metal, a conductive polymer material, or a resin obtained by adding a conductive filler to a non-conductive polymer material can be used. Specifically, examples of the metal include aluminum, nickel, iron, stainless steel, titanium, and copper. In addition to this, a clad material of nickel and aluminum, a clad material of copper and aluminum, a plating material of a combination of these metals, or the like is preferably used. Further, it may be a foil in which a metal surface is coated with aluminum. Among these, aluminum, stainless steel, copper, and nickel are preferable from the viewpoints of electron conductivity, battery operating voltage, and adhesion of the negative electrode active material to the current collector by a sputtering method.

Further, examples of the conductive polymer material include polyaniline, polypyrrole, polythiophene, polyacetylene, polyparaphenylene, polyphenylacetylene, polyacrylonitrile, and poly.

Diazole and the like. Since such a conductive polymer material has sufficient conductivity without adding a conductive filler, it is advantageous in terms of facilitating the production process or reducing the weight of the current collector.

Examples of the non-conductive polymer material include polyethylene (PE; high density polyethylene (HDPE), low density polyethylene (LDPE), etc.), polypropylene (PP), and polyethylene terephthalate. (PET), polyether nitrile (PEN), polyimide (PI), polyamideimide (PAI), polyamide (PA), polytetrafluoroethylene (PTFE), styrene butadiene rubber (SBR), poly Acrylonitrile (PAN), polymethyl acrylate (PMA), polymethyl methacrylate (PMMA), polyvinyl chloride (PVC), polyvinylidene fluoride (PVdF), polystyrene (PS), and the like. Such a non-conductive polymer material can have excellent withstand voltage or solvent resistance.

A conductive filler may be added to the above-mentioned conductive polymer material or non-conductive polymer material as needed. In particular, when the resin which is the base material of the current collector is composed only of the non-conductive polymer, in order to impart conductivity to the resin, a conductive filler is inevitably required. The conductive filler can be used without particular limitation as long as it is electrically conductive. For example, as a material excellent in conductivity, voltage resistance, or lithium ion barrier property, a metal, conductive carbon, or the like can be given. The metal is not particularly limited, and preferably contains at least one metal selected from the group consisting of Ni, Ti, Al, Cu, Pt, Fe, Cr, Sn, Zn, In, Sb, and K, or an alloy or metal oxide containing the same. . Further, the conductive carbon is not particularly limited, and preferably contains acetylene black, Vulcan (registered trademark), Black Pearl (registered trademark), carbon nanofiber, Ketjen Black (registered trademark), carbon nanotube, carbon nanohorn ( Carbon Nanohorn), at least one of carbon nanospheres and fullerenes. The amount of the conductive filler to be added is not particularly limited as long as it can impart a sufficient conductivity to the current collector. Generally, it is about 5 to 35 wt% of the entire current collector.

Further, as the cathode current collector, any known material used as a cathode current collector can be used; as the anode current collector, any known material used as a cathode current collector can be used.

In the present invention, it is preferable that at least one of the cathode current collector and the anode current collector is a porous current collector from the viewpoint of reducing the internal resistance of the supercapacitor. The porous current collector may be in the form of a mesh, a sponge, a nonwoven fabric or a through hole.

2-3. Electrode

The electrode (positive electrode, negative electrode) may be prepared by forming the active material (positive electrode active material, negative electrode active material) layer on the current collector (positive electrode current collector, negative electrode current collector) by a conventionally known method, but is not limited thereto. this. One skilled in the art can select an appropriate method to fabricate the electrode depending on the type of supercapacitor to be fabricated.

The production of an electrode using an electrode active material can be carried out by a conventional method. That is, the electrode active material and the conductive agent, and a binder and a thickener which are used as needed may be dry-mixed and formed into a sheet shape, and the sheet material may be pressed onto the electrode current collector, or These materials are dissolved or dispersed in a liquid medium to prepare a slurry, which is applied onto an electrode current collector and dried, whereby an electrode active material layer is formed on the current collector, thereby obtaining an electrode.

The content of the electrode active material in the electrode active material layer may be, for example, 50% by weight or more, 60% by weight or more, 70% by weight or more, 75% by weight or more, 80% by weight or more, 82% by weight or more, 84% by weight or more, and 87%. The weight% or more, 88% by weight or more, and 90% by weight or more. Further, the upper limit thereof may be, for example, 99% by weight or less, 98% by weight or less, 95% by weight or less, 92% by weight or less, 90% by weight or less, 85% by weight or less, 80% by weight or less, 75% by weight or less, or 70% by weight. Hereinafter, it is 65% by weight or less, 60% by weight or less, and 55% by weight or less.

In order to increase the packing density of the electrode active material in the electrode active material layer obtained by coating and drying, it is preferable to carry out compaction by a manual press, a roll press, or the like. The lower limit of the density of the electrode active material layer is preferably 1.5 g/cm ³ or more, more preferably 2 g/cm ³ , still more preferably 2.2 g/cm ³ or more, and the upper limit thereof is preferably 3.5 g/cm ³ or less. It is more preferably 3 g/cm ³ or less, and still more preferably 2.8 g/cm ³ or less.

As the conductive agent, it may contain graphene. The conductive agent may contain, in addition to the graphene, any other component that can be used as a conductive agent. For example, it may include: a metal material such as copper or nickel; a graphite such as natural graphite or artificial graphite; a carbon black such as acetylene black; and a carbon material such as amorphous carbon such as needle coke. These conductive agents may be used singly or in combination of two or more kinds in any combination and in any ratio. The conductive agent may be 0.01 to 50% by weight, 0.1 to 40% by weight, 0.5 to 35% by weight, 1 to 30% by weight, or 2 to 25% by weight, based on the total weight of the electrode active material layer. 5 to 20% by weight and 10 to 15% by weight.

Further, the electrode active material layer may further contain a binder. The binder used for the production of the electrode active material layer is not particularly limited, and in the case of a coating method, it may be a material that can be dissolved or dispersed in a liquid medium used in the production of an electrode. Examples thereof include resin polymers such as polyethylene, polypropylene, polyethylene terephthalate, polymethyl methacrylate, polyimide, aromatic polyamide, cellulose, and nitrocellulose. ;SBR (styrene-butadiene rubber), NBR (nitrile rubber), fluororubber, isoprene rubber, butadiene rubber, ethylene propylene rubber and other rubber-like polymers; styrene-butadiene-benzene Ethylene block copolymer or hydrogenated product thereof, EPDM (ethylene-propylene-diene terpolymer), styrene-ethylene-butadiene-ethylene copolymer, styrene-isoprene-styrene block Thermoplastic elastomeric polymer such as copolymer or hydrogenated product thereof; soft syndiotactic 1,2-polybutadiene, polyvinyl acetate, ethylene-vinyl acetate copolymer, propylene-α-olefin copolymer, etc. Resin-like polymer; polyvinylidene fluoride (PVdF), polytetrafluoroethylene, fluorinated polyvinylidene fluoride A fluorine-based polymer such as a polytetrafluoroethylene-ethylene copolymer; a polymer composition having an ion conductivity of an alkali metal ion (particularly, lithium ion). It is to be noted that these may be used singly or in combination of two or more kinds in any combination and in any ratio.

The ratio of the binder in the total weight of the electrode active material layer is usually 0.1% by weight or more, preferably 1% by weight or more, more preferably 3% by weight or more, and the upper limit is usually 80% by weight or less, preferably 60%. The weight% or less, more preferably 40% by weight or less, and most preferably 10% by weight or less.

The solvent for forming the slurry may be any solvent that can dissolve or disperse the electrode active material, the conductive agent, the binder, and the thickener used as needed, and the kind thereof is not particularly limited, and water can be used. Any solvent in the solvent and organic solvent. Examples of the aqueous medium include water, a mixed medium of an alcohol and water, and the like. Examples of the organic medium include aliphatic hydrocarbons such as hexane; aromatic hydrocarbons such as benzene, toluene, xylene, and methylnaphthalene; heterocyclic compounds such as quinoline and pyridine; acetone, methyl ethyl ketone, and cyclohexanone. Ketones; esters such as methyl acetate and methyl acrylate; amines such as diethylenetriamine and N,N-dimethylaminopropylamine; ethers such as diethyl ether, propylene oxide and tetrahydrofuran (THF); N- An amide such as methylpyrrolidone (NMP), dimethylformamide or dimethylacetamide; a polar aprotic solvent such as hexamethylphosphoramide or dimethyl sulfoxide. In particular, in the case of using an aqueous medium, it is preferred to use a thickener and a latex such as styrene-butadiene rubber (SBR) for slurrying.

Thickeners are commonly used to adjust the viscosity of the slurry. A thickener may also be included in the electrode active material layer. The thickener is not particularly limited, and specific examples thereof include carboxymethylcellulose, methylcellulose, hydroxymethylcellulose, ethylcellulose, polyvinyl alcohol, oxidized starch, phosphorylated starch, and casein. Their salt and so on. These thickeners may be used alone or in combination of two or more kinds in any combination and in any ratio. Further, when a thickener is added, the ratio of the thickener to the total weight of the electrode active material layer is 0.1% by weight or more, preferably 0.5% by weight or more, more preferably 0.6% by weight or more, and the upper limit is 5 It is a weight % or less, preferably 3% by weight or less, and more preferably 2% by weight or less.

3. Supercapacitor

The electrode of the present invention can be used in a supercapacitor. Accordingly, in another aspect, the present invention provides a supercapacitor (supercapacitor of the present invention) comprising a positive electrode, a negative electrode, a separator, and an electrolyte, wherein any one or all of the positive and negative electrodes are the present invention electrode.

The separator is typically disposed between the positive and negative electrodes. The material and shape of the separator are not particularly limited, and a known separator can be arbitrarily used. For example, a resin, a glass fiber, an inorganic material, or the like can be used, and a porous sheet or a nonwoven fabric-like material having excellent liquid retention properties is preferably used.

As a material of the resin or the glass fiber separator, for example, polyolefin such as polyethylene or polypropylene, aromatic polyamide, polytetrafluoroethylene, polyether sulfone, glass filter or the like can be used. Among them, a glass filter and a polyolefin are preferable, and a polyolefin is further preferable. The above materials may be used singly or in combination of two or more kinds in any combination and in any ratio. The separator may have any thickness, and may be, for example, 1 μm or more, preferably 5 μm or more, more preferably 8 μm or more, and usually 50 μm or less, preferably 40 μm or less, and more preferably 30 μm or less. When a porous material such as a porous sheet or a nonwoven fabric is used as the separator, the porosity of the separator is arbitrary, and may be, for example, 20% or more, preferably 35% or more, more preferably 45% or more, and usually 90% or less. It is preferably 85% or less, and more preferably 75% or less. The average pore diameter of the separator is also arbitrary, and may be, for example, 0.5 μm or less, preferably 0.2 μm or less, and usually 0.05 μm or more. On the other hand, as the material of the inorganic material, an oxide such as alumina or silica, a nitride such as aluminum nitride or silicon nitride, a sulfate such as barium sulfate or calcium sulfate can be used, and a particle shape or a fiber shape can be used. Inorganic materials. As the form of the separator, a film shape such as a nonwoven fabric, a woven fabric, or a microporous film can be used. Among the film shapes, a film having a pore diameter of 0.01 to 1 μm and a thickness of 5 to 50 μm is preferably used. In addition to the above-described independent film shape, a separator obtained by forming a composite porous layer containing the above inorganic particles in a surface layer of a positive electrode and/or a negative electrode using a resin binder may be used. For example, a fluororesin is used as a binder, and alumina particles having a 90% particle diameter of less than 1 μm are formed into a porous layer on both surfaces of the positive electrode.

An electrolyte is filled between the positive electrode and the negative electrode. The electrolyte may be an aqueous electrolyte or a non-aqueous electrolyte. Further, the electrolyte may be an electrolyte, a polymer gel electrolyte, or a solid polymer electrolyte.

The electrolytic solution has, for example, a structure obtained by dissolving a supporting salt (lithium salt) in an organic solvent. Examples of the lithium salt include inorganic acid anion salts selected from LiPF ₆ , LiBF ₄ , LiClO ₄ , LiAsF ₆ , LiTaF ₆ , LiAlCl ₄ , Li ₂ B ₁₀ Cl ₁₀ , LiCF ₃ SO ₃ , and Li (CF _{3 ).} At least one lithium salt of an organic acid anion salt such as SO ₂ ) ₂ N or Li(C ₂ F ₅ SO ₂ ) ₂ N or the like. Further, as the organic solvent, for example, a cyclic carbonate selected from the group consisting of propylene carbonate (PC) and ethylene carbonate (EC); dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), Chain carbonates such as diethyl carbonate (DEC); tetrahydrofuran, 2-methyltetrahydrofuran, 1,4-dioxane, 1,2-dimethoxyethane, 1,2-dibutyl Ethers such as oxyethane; lactones such as γ-butyrolactone; nitriles such as acetonitrile; esters such as methyl propionate; amides such as dimethylformamide; and at least methyl acetate and methyl formate A solvent obtained by mixing one or more kinds of organic solvents such as an aprotic solvent.

As the electrolytic solution, a sodium salt and the above additives can be dissolved in a nonaqueous solvent as an organic solvent. The mixing ratio of the additives is not particularly limited, but is preferably contained in a proportion of 0.5 to 10% by volume in the nonaqueous electrolytic solution, more preferably 0.5 to 5% by volume, and still more preferably 0.5 to 2% by volume. The sodium salt may, for example, be an inorganic acid anion salt selected from the group consisting of NaPF ₆ , NaBF ₄ , NaClO ₄ , NaAsF ₆ , NaTaF ₆ , NaAlCl ₄ , Na ₂ B ₁₀ Cl ₁₀ , NaCF ₃ SO ₃ , Na(CF ₃ SO). ₂ ) at least one sodium salt of an organic acid anion salt such as ₂ N or Na(C ₂ F ₅ SO ₂ ) ₂ N. Further, as the nonaqueous solvent, for example, a nonaqueous solvent composed of a saturated cyclic carbonate or a nonaqueous solvent composed of a saturated cyclic carbonate and a chain carbonate can be applied. Examples of the saturated cyclic carbonate include ethylene carbonate (EC), propylene carbonate (PC), and butylene carbonate (BC). Further, examples of the chain carbonate include dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC). Further, other nonaqueous solvents may be contained. For example, a solvent selected from the group consisting of one or more selected from the group consisting of tetrahydrofuran, 2-methyltetrahydrofuran, and 1,4-dioxane may also be used. An ether such as an alkane, 1,2-dimethoxyethane or 1,2-dibutoxyethane; a lactone such as γ-butyrolactone; a nitrile such as acetonitrile; or an ester such as methyl propionate; Amide such as dimethylformamide; methyl acetate or methyl formate.

Further, examples of the electrolytic solution include an aqueous solution containing potassium hydroxide.

Examples of the electrolytic solution include dilute sulfuric acid.

The electrolyte may also be impregnated in the separator.

The polymer gel electrolyte includes a polymer gel electrolyte containing a polymer constituting the polymer gel electrolyte and an electrolytic solution in a conventionally known ratio. The content of the polymer in the polymer gel electrolyte is preferably, for example, about several weight% to 98% by weight from the viewpoint of ionic conductivity and the like.

The solid polymer electrolyte is, for example, an electrolyte having a configuration in which the electrolyte salt is dissolved in polyoxyethylene (PEO), polyoxypropylene (PPO), or the like, and does not contain an organic solvent.

4. Circuit

In another aspect of the invention, an electrical circuit (circuit of the invention) comprising the supercapacitor of the invention is provided. Electrical appliances may also be included in the circuit of the present invention. The electrical appliance refers to the electrical components connected to the two ends of the power supply in the circuit, and the electrical energy is converted into other forms of energy by the electrical appliance. The electrical appliances can be, for example, resistors and capacitors.

5. Electrical equipment

In another aspect of the invention, an electrical device (electrical device of the invention) is provided comprising the circuit of the invention. Examples of the electric equipment include an electric motor that converts electric energy into mechanical energy, an electric heater that converts electric energy into thermal energy, an electric light source that converts electric energy into light energy, and the like, but is not limited thereto. Further, as specific examples of the electric equipment, for example, a refrigerator, a cold drink machine, an air conditioner, an electric fan, a ventilating fan, a cold air heater, an air dehumidifier, a washing machine, a clothes dryer, an electric iron, a vacuum cleaner, and a floor waxing can be cited. Machine, microwave oven, induction cooker, electric oven, rice cooker, dishwasher, electric water heater, electric blanket, electric heating, electric heating suit, space heater, electric shaver, hair dryer, hairdresser, ultrasonic washer, Electric massagers, pico projectors, televisions, radios, recorders, video recorders, video cameras, stereos, pyrotechnic alarms, electric bells, electric lights, computers, automobiles, trains, airplanes, ships, vacuum switches, instrumentation, digital cameras, etc.

Example

The invention is more specifically described by the following examples, but the invention is not limited by these examples.

Unless otherwise specified, "parts" hereinafter means "parts by weight" and "%" means "% by weight".

Preparation and Characterization of Activated Carbon Microspheres of Examples 1-12

As detailed in Table 1 below, 100 parts of carbon source and 25 parts of catalyst were prepared, and the above carbon source and catalyst were added to 4000 parts of water, and hydrothermal reaction was carried out under the specific conditions shown in Table 1 below, followed by suction filtration to obtain a primary. Carbon microspheres; then the primary carbon microspheres prepared above were placed in a porcelain boat, and heated in a 60 mL/min inert gas atmosphere at a rate of 5 ° C/min in a tube furnace, and the temperature was raised to the temperature shown in Table 1 below. The carbonization reaction is carried out, and then the carbonized carbon microspheres are placed in a nickel box, placed in a tube furnace, and heated at a rate of 5 ° C/min. Under an inert gas atmosphere of 60 mL/min, according to the following Table 1. The specific conditions shown were subjected to an activation reaction, followed by acid neutralization, hot water washing, and dry pulverization to obtain activated carbon microspheres of Examples 1-12.

The SEM photograph of the activated carbon microspheres obtained in Example 6 is shown in Fig. 1, the pore volume-pore size distribution is shown in Fig. 2, and the BET specific surface area is shown in Fig. 3. The SEM photograph of the activated carbon microspheres obtained in Example 9 is shown. As shown in Fig. 4, the pore volume-pore size distribution is as shown in Fig. 5, and the BET specific surface area is as shown in Fig. 6.

The microsphere morphology and bulk density of the obtained activated carbon microspheres are shown in Table 1 below.

The morphology of the microspheres in Table 1 was mainly determined by electron microscopy. The agglomerated adhesion microspheres were dispersed by a high-efficiency disperser (VC-100). The dispersion conditions were 200-1000 r/min and 30 min-60 min. Then, the dispersed activated carbon microspheres were photographed by SEM electron microscopy. According to the microspheres shown in the SEM photograph, the number of microspheres under different particle diameters was counted and counted by the naked eye and according to the scale given in the photograph. According to the results of counting, the percentage of activated carbon microspheres with a particle size distribution of 0.5-10 μm to all carbon microspheres was calculated, and the percentage of activated carbon microspheres with a particle size distribution of 5-15 μm accounted for all carbon microspheres.

The bulk density in Table 1 was mainly detected by a tap density meter (HNT-301).

The particle size distribution ratio in Table 1 was measured according to the Laser measurement standard using a laser particle size distribution analyzer Bettersize 2000 LD. The carbon medium was used as a reference, and the aqueous medium was dispersed, and then tested.

Table 1

Example 13 Preparation and Performance Testing of Supercapacitors

The activated carbon microspheres obtained in Examples 1-12 were used as the electrode active material of the negative electrode, and a supercapacitor was prepared. The specific capacitance of the supercapacitor fabricated using the materials of Examples 1-12 was tested as shown in Table 2 below). It can be prepared and tested by a conventionally known method, and a person skilled in the art can select a suitable method depending on the type of supercapacitor to be manufactured. For example, the preparation of supercapacitors and the detection of indicators are mainly referred to "the application of carbon materials in supercapacitors", Liu Yurong, National Defense Industry Press.

Table 2

Example	Specific capacitance F/g
1	8.8
2	9.2
3	8.9
4	9.7
5	9.3
6	9.8
7	11.7
8	9.1
9	9.0
10	10.1
11	9.4
12	8.7

It can be seen that the carbon microspheres prepared in Examples 1 to 12 of the present invention are used to manufacture supercapacitors, and the obtained specific capacitance is high.

Claims (20)

1. An activated carbon microsphere, wherein the activated carbon microspheres have a particle size distribution of 0.5-15 μm, and the activated carbon microspheres having a particle size distribution of 0.5-10 μm account for 10-90%, and the particle size distribution is 5-15 μm. Activated carbon microspheres account for 90-10%.
2. The activated carbon microsphere according to claim 1, wherein the activated carbon microspheres have an average particle diameter D10 of 0.5 to 5 μm and a D50 of 7 to 10 μm, preferably D10 of 1 to 4 μm, more preferably 2-3 μm, and preferably D50 7-9 μm, more preferably 7.5-8.5 μm.
3. The activated carbon microspheres according to claim 1 or 2, wherein the activated carbon microspheres having a particle size distribution of from 0.5 to 10 μm account for from 20 to 80%, preferably from 30 to 70%, more preferably from 40 to 60%, still more preferably 45. -55%; activated carbon microspheres having a particle size distribution of 5-15 μm accounted for 80-20%, preferably 70-30%, more preferably 60-40%, more preferably 55-45%.
4. The activated carbon microspheres according to any one of claims 1 to 3, wherein the activated carbon microspheres have a bulk density of 0.5 to 1.5 g/cm ³ , preferably 0.5 to 1.2 g/cm ³ , more preferably 0.6 to 0.9. g/cm ³ .
5. A method for producing activated carbon microspheres, comprising the steps of:

   Step A: Prepare a carbon source;

   Step B: hydrothermally reacting the carbon source to obtain primary carbon microspheres;

   Step C: The primary carbon microspheres are subjected to a carbonization reaction and an activation reaction to obtain activated carbon microspheres.
6. The manufacturing method according to claim 5, wherein the carbon source is glucose, xylose or cellulose.
7. The production method according to claim 5 or 6, wherein the carbon source has a concentration of from 1 to 99% by weight, preferably from 3 to 70% by weight, more preferably from 5 to 60% by weight, still more preferably from 7 to 50% by weight, More preferably, it is 10-40% by weight of an aqueous glucose solution.
8. The manufacturing method according to claim 7, wherein the glucose is derived from corn starch hydrolysis.
9. The production method according to any one of claims 5 to 8, wherein the reaction temperature of the hydrothermal reaction is from 120 to 180 °C.
10. The production method according to any one of claims 5 to 9, wherein the reaction time of the hydrothermal reaction is from 3 to 6 hours.
11. The production method according to any one of claims 5 to 10, wherein a catalyst is used in the hydrothermal reaction, and the catalyst is selected from the group consisting of a hydroxyl group-like phosphate and a derivative thereof, and a weak acid and an alkali metal. Salts, and acids (generally inorganic acids).
12. The production method according to any one of claims 5 to 11, wherein a weight ratio of the carbon source (in terms of carbon) to the catalyst is from 1:1 to 10:1, preferably from 2:1 to 6: 1. More preferably 3:1 to 4:1.
13. The production method according to any one of claims 5 to 12, which is the method for producing the activated carbon microspheres according to any one of claims 19 to 22.
14. An electrode comprising an electrode current collector and an electrode active material layer present on the electrode current collector, the electrode active material layer comprising at least activated carbon microspheres as an electrode active material; wherein the activated carbon microspheres are claimed The activated carbon microspheres according to any one of claims 1 to 4, or the production method according to any one of claims 5 to 13.
15. The electrode according to claim 14, wherein the electrode is a positive electrode.
16. The electrode according to claim 14, wherein the electrode is a negative electrode.
17. The electrode according to any one of claims 14 to 16, wherein the electrode is for a supercapacitor.
18. A supercapacitor comprising a positive electrode, a negative electrode, a separator, and an electrolyte, wherein any one or all of the positive electrode and the negative electrode are the electrode according to any one of claims 14 to 17.
19. A circuit comprising the ultracapacitor of claim 18.
20. An electrical device comprising the circuit of claim 19.

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