JP4045831B2 - Electrode cell electrode material and electrochemical cell using the same - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to an electrode material for an electrochemical cell having a disulfide group.
[0002]
[Prior art]
As an electrode material for an electrochemical cell that can be expected to have a high energy density, a disulfide compound that is an organic sulfur compound is disclosed in US Pat. No. 4,833,048. This organic sulfur compound is represented most simply by R—S—S—R (R is a hydrocarbon and S is sulfur), and the S—S bond is cleaved by an electroreduction reaction, and the metal ion M in the electrolyte ⁺ city with 2R ^- · M ⁺ to generate the metal salt represented by. This metal salt returns to the original R—S—S—R by the electrolytic oxidation reaction. A metal-disulfide secondary battery in which a metal M that supplies and captures metal ions M ⁺ and a disulfide compound is combined is proposed in the aforementioned US patent. This battery can be expected to have a high energy density of 150 Wh / kg or more.
[0003]
[Problems to be solved by the invention]
However, since the metal salt is easily dissolved in the organic electrolyte, it is difficult to use the metal salt as an electrode material for an electrochemical cell using the organic electrolyte, particularly for a secondary battery.
[0006]
[Means for Solving the Problems]
The invention as described in claim 1, in the molecule, and an alkene structure, R-S-S-R (R is a hydrocarbon in the electrolytic oxidation state possible electrolytic oxidation reduction reaction, S is sulfur organic sulfur compound having sulfur taking a structure represented by shown), wherein the alkene is an electrode material for an electrochemical cell, comprising a polymer sulfur compound formed by chemical crosslinking.
[0007]
Since the electrode material for an electrochemical cell of the present invention is a polymer organic sulfur compound in which a chemically crosslinkable alkene is crosslinked, a thin film electrode plate can be produced. That is, since a thin film is prepared by dissolving a chemically crosslinkable alkene in a solvent, it can be polymerized by crosslinking, which is convenient for preparing a thin electrode. Moreover, it can also be used as a conductive agent-polymeric organic sulfur compound complex by crosslinking the chemically crosslinkable alkene of the present invention on the surface of a core material (conductive agent) having excellent electron conductivity.
[0008]
Moreover, as described in claim 2 , the present invention is an electrode material for an electrochemical cell, wherein the organic sulfur compound is represented by the following (Chemical Formula 1).
[0009]
[Chemical 2]
[0010]
(However, at least one of R1, R2, R3 and R4 is an organic functional group containing sulfur capable of electrolytic redox reaction .)
That is, the organic functional group containing sulfur capable of electrolytic redox reaction is any one or more of R1, R2, R3, and R4 in (Chemical Formula 1). Such a structure is relatively easy to synthesize and the chemical crosslinking reaction also proceeds easily.
[0011]
Further, according to the present invention, as defined in claim 3 , in (Chemical Formula 1), at least one of R1, R2, R3 and R4 is o-mercaptophenyl, m-mercaptophenyl, p-mercapto. It is characterized by having phenyl or a metal salt thereof. That is, if the organic functional group containing sulfur capable of electrolytic redox reaction is one of o-mercaptophenyl, m-mercaptophenyl, p-mercaptophenyl, or a metal salt thereof, synthesis is relatively easy. is there.
[0012]
Further, according to the present invention, as described in claim 4 , in the chemical formula 1, two or more of R1, R2, R3 and R4 are o-mercaptophenyl, m-mercaptophenyl, p-mercapto. It is characterized by having phenyl or a metal salt thereof. That is, if the organic functional group containing sulfur capable of electrolytic redox reaction is one of o-mercaptophenyl, m-mercaptophenyl, p-mercaptophenyl, or a metal salt thereof, synthesis is relatively easy. There are many reaction points and the theoretical capacity increases, so that the electrode material has a high capacity.
[0013]
Moreover, this invention is an electrochemical cell using these electrode materials for electrochemical cells, as described in claim 5 .
[0014]
The electrode material of the present invention can be used for electrochemical cells such as capacitors and batteries. As a battery, it can be used for a proton battery or an aprotic battery.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the description will be made assuming that the electrode material of the present invention is used as the electrode material for a lithium battery, but the present invention is not limited to the following description.
[0016]
When the electrode material for electrochemical cells of the present invention is used as a positive electrode active material for a lithium battery, a material generally used for a negative electrode for a lithium battery can be used as the negative electrode active material. For example, lithium-containing alloys such as lithium metal, lithium-aluminum, lithium-lead, lithium-tin, lithium-aluminum-tin, lithium-gallium, and wood alloy, and the following carbon materials are exemplified. Examples include natural graphite, artificial graphite, amorphous carbon, fibrous carbon, powdered carbon, petroleum pitch-based carbon, and coal coke-based carbon. These carbon materials are preferably particles or fibers having a diameter or fiber diameter of 0.01 to 10 μm and a fiber length of several μm to several mm. In particular, the carbon material is
This graphite is preferable because of its high capacity. However, it is not limited to these ranges.
[0017]
Furthermore, it is possible to modify the carbon material by adding a metal oxide such as tin oxide or silicon oxide, or by adding phosphorus or boron. Moreover, it is also possible to insert lithium in advance into the carbonaceous material used in the present invention by using graphite and lithium metal, a lithium-containing alloy or the like in combination or by electrochemical reduction in advance.
[0018]
When the electrode material for electrochemical cells of the present invention is used as a negative electrode active material for a lithium battery, a material generally used for a positive electrode for a lithium battery can be used as the positive electrode active material. For example, materials such as lithium-containing transition metal oxides and phosphates that exhibit a discharge voltage of 3 V or more with respect to lithium are preferably used. In particular, a material capable of obtaining a discharge potential of 4 V or more is more preferable because a high battery voltage can be obtained and the energy density is improved. Examples of the lithium-containing transition metal oxide include Li _y Co _1-x M _x O ₂ , Li _y Mn _{2 -x} M _x O ₄ {M is a group I to VIII metal (for example, Li, Ca , Cr, Ni, Fe, Co, Mn, etc.), and the x value indicating the amount of substitution of different elements is effective up to the maximum amount that can be replaced, but preferably 0 ≦ from the point of discharge capacity x ≦ 1. In addition, as the y value indicating the amount of lithium, the maximum amount capable of reversibly utilizing lithium is effective, but preferably 0 <y ≦ 2 from the viewpoint of discharge capacity. }, But is not limited thereto. However, since the electrode material of the present invention has a relatively noble potential when used for a negative electrode, a positive electrode active material that operates at a more noble potential is preferable.
[0019]
Other active materials can be further mixed with the lithium-containing transition metal oxide. For example, Group I metal compounds such as CuO, Cu ₂ O, Ag ₂ O, CuS, CuSO ₄ , Group IV metal compounds such as TiS ₂ , SiO ₂ , SnO, V ₂ O ₅ , V ₆ O ₁₂ , VO _x , Group V metal compounds such as Nb ₂ O ₅ , Bi ₂ O ₃ , Sb ₂ O ₃ , Group VI metal compounds such as CrO ₃ , Cr ₂ O ₃ , MoO ₃ , MoS ₂ , WO ₃ , SeO ₂ , MnO ₂ , Examples include Group VII metal compounds such as Mn ₂ O ₃ and Group VIII metal compounds such as Fe ₂ O ₃ , FeO, Fe ₃ O ₄ , FePO ₄ , Ni ₂ O ₃ , NiO, CoO ₃ , and CoO. Furthermore, conductive polymer compounds such as polypyrrole, polyaniline, polyparaphenylene, polyacetylene, and polyacene materials, pseudographite structure carbonaceous materials, and the like may be used, but are not limited thereto.
[0020]
Examples of the method for forming the electrode material of the present invention include an arbitrary thickness and an arbitrary thickness on the current collector using means such as roller coating such as an applicator roll, screen coating, doctor blade method, spin coating, and bar coder. However, the present invention is not limited to these. In addition, when these means are used, it is possible to increase the actual surface area of the electrochemically active substance in contact with the electrolyte layer and the current collector.
[0021]
In the electrode material of the present invention, a conductive agent, a binder, a filler and the like can be added to the electrode mixture as necessary.
[0022]
As the conductive agent, any electronic conductive material that does not adversely affect battery performance may be used. Usually, natural graphite (scale-like graphite, scale-like graphite, earth-like graphite, etc.), artificial graphite, carbon black, acetylene black, ketjen black, carbon whisker, carbon fiber and metal (copper, nickel, aluminum, silver, gold, etc.) Conductive materials such as powders, metal fibers, and conductive ceramic materials can be included as one type or a mixture thereof. Among these, acetylene black is desirable from the viewpoints of conductivity and coatability. The addition amount is preferably 1 to 50% by weight, particularly preferably 2 to 30% by weight. These mixing methods are physical mixing, and the ideal is uniform mixing. Therefore, powder mixers such as V-type mixers, S-type mixers, crackers, ball mills, and planetary ball mills can be mixed dry or wet.
[0023]
As the binder, heat such as tetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, ethylene-propylene diene terpolymer (EPDM), sulfonated EPDM, styrene butadiene rubber (SBR), fluorine rubber, carboxymethyl cellulose, etc. A plastic resin, a polymer having rubber elasticity, a polysaccharide, or the like can be used as one kind or a mixture of two or more kinds. In addition, it is desirable that a binder having a functional group that reacts with lithium, such as a polysaccharide, be deactivated by, for example, methylation. The addition amount is preferably 1 to 50% by weight, particularly preferably 2 to 30% by weight.
[0024]
The filler may be any material as long as it does not adversely affect battery performance. Usually, olefin polymers such as polypropylene and polyethylene, aerosil, zeolite, glass, carbon and the like are used. The amount of filler added is preferably 0 to 30% by weight.
[0025]
It is also possible to add chalcogen elements such as sulfur, selenium and tellurium to the electrode material of the present invention. The chalcogen element is added to the S—S bond of the disulfide group of the electrode material, and the electrochemical capacity is further increased. The amount of the chalcogen element added is preferably 30% by weight or less with respect to the electrode material of the present invention.
[0026]
Any positive electrode current collector and negative electrode current collector may be used as long as they are electronic conductors that do not have an adverse effect on the constructed battery. For example, as the positive electrode current collector, aluminum, titanium, stainless steel, nickel, calcined carbon, conductive polymer, conductive glass, etc., as well as aluminum and copper for the purpose of improving adhesion, conductivity, and oxidation resistance. A material obtained by treating the surface such as carbon, nickel, titanium, silver, or the like can be used. In addition to copper, nickel, iron, stainless steel, titanium, aluminum, calcined carbon, conductive polymer, conductive glass, Al-Cd alloy, etc., as negative electrode current collector, adhesiveness, conductivity, oxidation resistance For the purpose of improvement, a material obtained by treating the surface of copper or the like with carbon, nickel, titanium, silver or the like can be used. The surface of these materials can be oxidized. As for these shapes, in addition to the foil shape, a film shape, a sheet shape, a net shape, a punched or expanded product, a lath body, a porous body, a foamed body, a formed body of a fiber group, and the like are used. The thickness is not particularly limited, but a thickness of 1 to 500 μm is used. Among these current collectors, an aluminum foil excellent in oxidation resistance is used for the positive electrode, and a copper foil, nickel foil, iron foil, which is inexpensive and stable in a reduction field and has excellent electrical conductivity, And the alloy foil containing those parts is preferable. Furthermore, it is desirable that the surface roughness of the rough surface with excellent adhesion between the electrochemically active material layer and the current collector is 0.2 μmRa or more. The electrolytic foil is excellent for the purpose of obtaining such a rough surface.
[0027]
As the battery exterior material using the electrode material of the present invention, a metal can such as iron, stainless steel, and aluminum can be used. From the viewpoint of weight energy density, a metal foil and a resin film are laminated. A resin composite film is preferred. As an example of the metal foil, any foil such as aluminum, iron, nickel, copper, SUS, titanium, gold, silver and the like having no pinhole may be used, but a lightweight and inexpensive aluminum foil is preferable. In addition, a resin film having an excellent piercing strength such as a polyethylene terephthalate film or a nylon film on the outer surface and a thermoplastic and fusible film such as a polyethylene film or a nylon film on the inner surface is also suitably used. . From the viewpoint of solvent resistance, it is desirable to seal the opening of such a resin film with a thermoplastic resin.
[0028]
As separators for batteries using the electrode material of the present invention, polyolefin-based, polyester-based, polyacrylonitrile-based, polyphenylene sulfide-based, polyimide-based, and fluororesin-based microporous membranes and nonwoven fabrics can be used. Among them, it is preferable to treat the microporous membrane with poor wettability with a surfactant or the like.
[0029]
The porosity of the separator is preferably 98% by volume or less from the viewpoint of strength. Further, the porosity is preferably 20% by volume or more from the viewpoint of charge / discharge characteristics.
[0030]
Examples of the ionic compound used for the electrolyte in the battery using the electrode material of the present invention include LiClO ₄ , LiBF ₄ , LiAsF ₆ , LiPF ₆ , LiCF ₃ SO ₃ , LiCF ₃ CO ₂ , LiSCN, LiBr, LiI, Li Inorganic ion salts containing one of Li, Na, or K, such as ₂ SO ₄ , Li ₂ B ₁₀ Cl ₁₀ , NaClO ₄ , NaI, NaSCN, NaBr, KClO ₄ , KSCN, LiN (CF ₃ SO ₂ ) ₂ , LiN (C ₂ F ₅ SO ₂ ) ₂ , (CH ₃ ) ₄ NBF ₄ , (CH ₃ ) ₄ NBr, (C ₂ H ₅ ) ₄ NClO ₄ , (C ₂ H ₅ ) ₄ NI, (C ₃ H ₇ ) ₄ NBr, (n-C ₄ H ₉ ) ₄ NClO ₄ , (n-C ₄ H ₉ ) ₄ NI, (C ₂ H ₅ ) ₄ N-maleate, (C ₂ H ₅ ) ₄ N-benzoate, _{(C 2 H 5) 4 N} -phta Quaternary ammonium salts such as ate, lithium stearyl sulfonate, lithium octyl sulfonate, organic ion salts such as dodecylbenzene lithium sulfonate are exemplified.
[0031]
The ionic compound can be used by dissolving in an organic solvent or the like. Examples of the organic solvent include cyclic carbonates such as ethylene carbonate, propylene carbonate, butylene carbonate, chloroethylene carbonate, and vinylene carbonate; cyclic esters such as γ-butyrolactone and γ-valerolactone; dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, and the like. Chain esters such as methyl acetate and methyl butyrate; ethers such as tetrahydrofuran or derivatives thereof, 1,3-dioxane, 1,2-dimethoxyethane, methyl diglyme; nitriles such as acetonitrile and benzonitrile Dioxalane or a derivative thereof; sulfolane, sultone or a derivative thereof alone or a mixture of two or more thereof may be added. However, it is not limited to these. By adding such an organic solvent, battery characteristics such as cycle characteristics and stability can be improved.
[0032]
The electrolytic solution may be injected after the separator of the present invention is sandwiched between electrodes or stacked or wound. As the injection method, it is possible to inject at normal pressure, but a vacuum impregnation method or a pressure impregnation method may be used.
[0033]
As a battery electrolyte using the electrode material of the present invention, a lithium ion conductive solid electrolyte that is solid or solid at a temperature of −20 to 60 ° C. may be used. The solid electrolyte includes a polyethylene oxide derivative in which the ionic compound is dissolved or a polymer containing at least the derivative, a polypropylene oxide derivative or a polymer containing at least the derivative, polyphosphazene or the derivative, a polymer containing an ion dissociating group, phosphorus Acid ester polymer derivatives, polyvinyl pyridine derivatives, bisphenol A derivatives, polyacrylonitrile, polyvinylidene fluoride, polymer matrix material containing non-aqueous electrolyte in fluororubber, etc. (gel electrolyte), and ions such as inorganic solid electrolytes What consists of a conductive compound can be used.
[0034]
The electrode of the battery using the electrode material of the present invention is preferably used in combination with the solid electrolyte in order to ensure sufficient ion conductivity while suppressing elution of the electrode material into the electrolyte. For example, 4,4′-stilbene dithiol obtained by the method described below and acetylene black as a conductive agent are kneaded, and further, acrylate-modified polyethylene glycol as the polyethylene oxide derivative and LiN (CF _{3 as the} ionic compound). SO ₂ ) ₂ and azobisisobutyronitrile as a radical initiator are added and kneaded, and a paste-like substance formed by adding acetonitrile is applied onto an aluminum foil, heated to about 80 ° C. to remove acetonitrile, and further A method of performing thermal crosslinking at about 100 ° C. and using it as an electrode can be mentioned. As a crosslinking method, in addition to thermal crosslinking using a radical initiator and ultraviolet (UV) crosslinking, a method using an actinic ray is also preferable.
[0035]
In addition, the organic sulfur compound which is the electrode material of the present invention can be oxidized and disulfidized in advance. When used as an electrode material of a lithium battery, the active proton of thiol reacts with lithium to generate hydrogen gas, so that it is desirable to oxidize in advance.
[0036]
【Example】
[(1) Synthesis of 4,4′-stilbenedithiol (4SDT)]
4SDT was synthesized in five steps using parabromotoluene as a starting material.
[0037]
[First step: Synthesis of parabromobenzyl bromide]
20.6 ml (168.5 mmol) of parabromotoluene was mixed with 200 ml of carbon tetrachloride, and 30 g (168.5 mmol) of N-bromosuccinimide and 0.3 g (1) of α, α′-azobisisobutyronitrile (AIBN) (1 .8 mmol) was added and refluxed at 80 ° C. for 2 hours. Thereafter, the mixture was cooled to room temperature, insolubles were removed by Celite, and the filtrate was concentrated. The resulting crude crystals were recrystallized from diethyl ether to obtain parabromobenzyl bromide.
[0038]
[Second stage: Synthesis of parabromobenzaldehyde]
8.5 g (50 mmol) of parabromobenzyl bromide was dissolved in 50 ml of chloroform, and 9.09 g (65 mmol) of hexamethylenetetramine was gradually added and dissolved while stirring. When stirring was continued at room temperature for about 3 hours, a white precipitate (parabromobenzyl bromide hexamethylenetetramine salt) was precipitated, which was collected by filtration and air-dried for about 30 minutes. 12.12 g (31 mmol) of the obtained white precipitate was added to 100 ml of an acetic acid aqueous solution (90 ml of acetic acid, 10 ml of water) and refluxed at 120 ° C. for 16 hours. Thereafter, 100 ml of water was added while maintaining the temperature, and the mixture was heated and stirred for about 10 minutes. After cooling to room temperature, parabromobenzaldehyde precipitated as crystals, so it was collected by filtration, washed well with water and saturated aqueous sodium bicarbonate, Air-dried to obtain parabromobenzaldehyde.
[0039]
[Stage 3: Synthesis of parabromobenzyl bromide triphenylphosphonium salt]
11.89 g (47.6 mmol) of parabromobenzyl bromide was dissolved in 50 ml of acetone, and 13.11 g (50 mmol) of triphenylphosphine was gradually added and dissolved while stirring. When the stirring was continued at room temperature for about 2 hours, the desired product was precipitated, which was collected by filtration and sufficiently air-dried to obtain a parabromobenzyl bromide triphenylphosphonium salt.
[0040]
[Fourth Step: Synthesis of trans-4,4′-dibromostilbene]
Under a nitrogen stream, 9.23 g (18 mmol) of parabromobenzyl bromide triphenylphosphonium salt and 4 g (21.6 mmol) of parabromobenzaldehyde were suspended in 100 ml of dry THF (tetrahydrofuran), to which 50 ml of dry THF and tertiary butoxy were added. A solution prepared with 2.63 g (23.4 mmol) of potassium (t-BuOK) was gradually added dropwise. After stirring at room temperature for about 5 hours, the reaction was stopped with water, extracted with diethyl ether, washed well with water and then saturated brine, dried over sodium sulfate and concentrated under reduced pressure to obtain a crude product. Was recrystallized from chloroform to obtain trans-4,4′-dibromostilbene.
[0041]
[Fifth Step: Synthesis of trans-4,4′-stilbenedithiol (4SDT)]
338 mg (1 mmol) of trans-4,4′-dibromostilbene was dissolved in 50 ml of dry THF, cooled to −78 ° C., and stirred for 20 minutes. Thereafter, 1.26 ml of 1.6 M normal butyl lithium hexane solution was slowly dropped while maintaining the temperature. Further, stirring was continued for about 1 hour while paying attention to the temperature, and 64 mg (2 mmol) of sulfur that had been purified by sublimation in advance was added. The mixture was then stirred for 13 minutes, quenched with 10% hydrochloric acid, extracted with toluene, washed with saturated aqueous sodium hydrogen carbonate and saturated brine, dried over sodium sulfate, and concentrated under reduced pressure. Trans-4,4′-stilbenedithiol (4SDT) having the structure shown was obtained.
[0042]
[Chemical 3]
[0043]
[(2) Synthesis of 3,3′-stilbenedithiol (3SDT)]
The synthesis of 3SDT was synthesized in 6 steps using paratoluidine as a starting material.
[0044]
[First stage: Synthesis of 2-bromoparatoluidine]
Paratoluidine (10.7 g, 100 mmol) was added to glacial acetic acid (40 ml), refluxed for about 2 hours, cooled to 45 ° C., and maintained at 50-55 ° C., 5.1 ml (100 mmol) of bromine was slowly added dropwise. Thereafter, the mixture was stirred for 2 hours while maintaining the temperature, poured into a beaker containing 50 ml of 10% aqueous sodium hydrogen sulfite solution and 150 ml of ice water, and the resulting white precipitate was collected by filtration and air-dried for about 1 hour. The filtrate was added to 50 ml of ethanol and heated with stirring until refluxing began. When reflux begins, slowly add 30 ml of concentrated hydrochloric acid, and then reflux for about 3 hours. Crystals will precipitate, so cool to room temperature, filter, wash twice with cold ethanol, and air dry for about 30 minutes. The crude crystals thus obtained were added to 40 ml of water and stirred for about 1 hour, and then a 30% aqueous sodium hydroxide solution was slowly added. Thereafter, the mixture was extracted with diethyl ether, and the organic layer was washed with a 10% aqueous sodium bisulfite solution and saturated brine in that order, dried over sodium sulfate, and concentrated to obtain 2-bromoparatoluidine.
[0045]
[Second stage: Synthesis of metabromotoluene]
47.17 g (250.9 mmol) of 2-bromoparatoluidine was added to 160 ml of ethanol and cooled to 0 ° C. To this was carefully added 40 ml of concentrated sulfuric acid, and further cooling and stirring, an aqueous solution of 29.6 g (42.9 mmol) of sodium nitrite dissolved in 50 ml of water was gradually added dropwise. After stirring for about 30 minutes while maintaining the temperature, 8 g (125.9 mmol) of copper powder was added in several portions so that the reaction did not proceed vigorously. The mixture was further stirred for about 30 minutes while maintaining the temperature, and then stirred at room temperature for 2 hours. Thereafter, the reaction was stopped with water, the copper powder was filtered off using Celite, the filtrate was extracted with hexane, the organic layer was washed with saturated aqueous sodium hydrogen carbonate and saturated brine, dried over sodium sulfate, concentrated and distilled under reduced pressure. Gave metabromotoluene.
[0046]
[Stage 3: Synthesis of metabromobenzyl bromide]
20.6 ml (168.5 mmol) of metabromotoluene was mixed with 200 ml of carbon tetrachloride. 30 g (168.5 mmol) of N-bromosuccinimide and 0.3 g of AIBN (α, α′-azobisisobutyronitrile) (1 .8 mmol) was added and refluxed at 80 ° C. for 2 hours. Thereafter, the mixture was cooled to room temperature, insolubles were removed with Celite, and the filtrate was concentrated and distilled under reduced pressure to obtain metabromobenzyl bromide.
[0047]
[Fourth stage: synthesis of metabromobenzyl bromide triphenylphosphonium salt]
11.87 g (47.6 mmol) of metabromobenzyl bromide was dissolved in 50 ml of acetone, and 13.11 g (50 mmol) of triphenylphosphine was gradually added and dissolved while stirring. When the stirring was continued at room temperature for about 2 hours, the target product was precipitated, which was collected by filtration and sufficiently air-dried to obtain a metabromobenzyl bromide triphenylphosphonium salt.
[0048]
[Fifth Step: Synthesis of trans-3,3′-dibromostilbene]
Under a nitrogen stream, 5.12 g (10 mmol) of metabromobenzyl bromide triphenylphosphonium salt and 1.41 ml (12 mmol) of commercially available metabromobenzaldehyde were suspended in 70 ml of dry THF (tetrahydrofuran), and 50 ml of dry THF and Tasha were added thereto. A solution prepared with 2.24 g (20 mmol) of libutoxypotassium (t-BuOK) was gradually added dropwise. After stirring at room temperature for about 5 hours, the reaction was stopped with water, extracted with diethyl ether, washed well with water and then saturated brine, dried over sodium sulfate and concentrated under reduced pressure to obtain a crude product. Was recrystallized from ethanol to obtain trans-3,3′-dibromostilbene.
[0049]
[Step 6: Synthesis of trans-3,3′-stilbenedithiol (3SDT)]
338 mg (1 mmol) of trans-3,3′-dibromostilbene was dissolved in 50 ml of dry THF, cooled to −78 ° C., and stirred for 20 minutes. Thereafter, 1.26 ml of 1.6M n-butyllithium hexane solution was slowly added dropwise while maintaining the temperature. Further, stirring was continued for about 1 hour while paying attention to the temperature, and 64 mg (2 mmol) of sulfur that had been purified by sublimation in advance was added. The mixture was then stirred for 13 minutes, quenched with 10% hydrochloric acid, extracted with toluene, washed with saturated aqueous sodium hydrogen carbonate and saturated brine, dried over sodium sulfate, and concentrated under reduced pressure to obtain trans-3,3'-stilbene. Dithiol (3SDT) was obtained.
[(3) Synthesis of 2,2′-stilbenedithiol (2SDT)]
2SDT was synthesized in five steps using orthobromotoluene as a starting material.
[0050]
[First step: Synthesis of orthobromobenzyl bromide]
25 g (146.16 mmol) of orthobromotoluene was mixed with 350 ml of carbon tetrachloride, 26.02 g (146.16 mmol) of N-bromosuccinimide, 0.3 g of AIBN (α, α′-azobisisobutyronitrile) (1. 8 mmol) was added and refluxed for 2 hours. Thereafter, the mixture was cooled to room temperature, insolubles were removed using celite, the filtrate was concentrated under reduced pressure, and then distilled under reduced pressure to obtain orthobromobenzyl bromide.
[0051]
[Second stage: Synthesis of orthobromobenzyl bromide triphenylphosphonium salt]
Orthobromobenzyl bromide (12.5 g, 50 mmol) was mixed with acetone (50 ml), and triphenylphosphine (14 g, 53 mmol) was gradually added and dissolved therein. When the mixture was stirred at room temperature for about 3 hours, a white precipitate was precipitated. The precipitate was collected by filtration, washed with acetone, and then air-dried for about 30 minutes to obtain a bromobenzyl bromide triphenylphosphonium salt.
[0052]
[Stage 3: Synthesis of orthobromobenzaldehyde]
17.6 g (70 mmol) of orthobromobenzyl bromide was mixed with 60 ml of chloroform, and 13 g (93 mmol) of hexamethylenetetramine was gradually added thereto. When stirred at room temperature for about 3 hours, a white precipitate will be deposited. After filtration and washing with chloroform, the white powder obtained by air drying for about 30 minutes was mixed with an acetic acid aqueous solution (acetic acid 85 ml, water 15 ml), Refluxed for 16 hours. After 16 hours, the reaction solution cooled to room temperature was extracted with chloroform, and the organic layer was washed with saturated sodium bicarbonate water, water and saturated brine in that order, dried over sodium sulfate, concentrated under reduced pressure, and further distilled under reduced pressure. Orthobromobenzaldehyde was obtained.
[0053]
[Fourth Step: Synthesis of 2,2′-Dibromostilbene]
Orthobromobenzyl bromide triphenylphosphonium salt (5.12 g, 10 mmol) and orthobromobenzaldehyde (2.22 g, 12 mmol) were suspended in dry THF (70 ml), and the dry THF (50 ml) and tertiary butoxypotassium (t-BuOK) 1. The solution prepared with 68 g (15 mmol) was gradually added dropwise. After stirring at room temperature for about 5 hours, the reaction was stopped with water, extracted with diethyl ether, washed well with water and saturated brine, dried over sodium sulfate, and concentrated under reduced pressure to obtain a crude product as silica gel. Purification by column chromatography (hexane) gave a 2,2′-dibromostilbene-trans mixture.
[0054]
[Fifth Stage: Synthesis of 2,2′-stilbenedithiol]
338 mg (1 mmol) of 2,2′-dibromostilbene was dissolved in 50 ml of dry THF, cooled to −78 ° C. and stirred for 20 minutes. Thereafter, 1.26 ml of 1.6 M normal butyl lithium hexane solution was slowly dropped while maintaining the temperature. Further, stirring was continued for about 1 hour while paying attention to the temperature, and 64 mg (2 mmol) of sulfur that had been purified by sublimation in advance was added. The mixture was then stirred for 13 minutes, quenched with 10% hydrochloric acid and extracted with toluene. The organic layer was washed with saturated aqueous sodium hydrogen carbonate and saturated brine, dried over sodium sulfate, and concentrated under reduced pressure to give 2,2′- Stilbene dithiol (2SDT) was obtained.
[0055]
(Test cell 1)
A test cell shown in FIG. 1 was produced. FIG. 2 is a cross-sectional view. 34 mg of 4SDT obtained as described above and 10 mg of acetylene black were kneaded in an agate mortar, and 283 mg of an N-methylpyrrolidone solution in which 12% by weight of polyvinylidene fluoride was dissolved was added and further kneaded. Next, about 2 ml of N-methylpyrrolidone was added to make a paste. The paste-like substance is applied onto an aluminum foil as a working electrode current collector 12, heated to about 80 ° C. to remove N-methylpyrrolidone, and a working electrode material 11 containing 4SDT on the working electrode current collector 12. As a result, a working electrode 1 was obtained.
[0056]
As the electrolyte / separator 3, an ion conductive compound supported on a nonwoven fabric was used. The production method of the electrolyte / separator 3 is as follows. That is, a mixture of 10% by weight of acrylate-modified polyethylene glycol, 6% by weight of lithium tetrafluoroborate, and 30% by weight of ethylene carbonate to support an ion conductive compound layer on a polyethylene non-woven fabric on both sides of the non-woven fabric. The resultant was cast and irradiated with an electron beam with an electron dose of 80 kGy in an inert gas atmosphere to obtain an electrolyte / separator 3. The thickness of the electrolyte / separator 3 thus obtained was 30 μm.
[0057]
The counter electrode 2 was obtained by press-bonding lithium as the counter electrode material 21 to a nickel plate as the counter electrode current collector 22. Terminals 6 and 6 were attached to the working electrode 1 and the counter electrode 2, respectively. The counter cell 2, the electrolyte / separator 3 and the working electrode 1 were laminated in this order to constitute an electrochemical cell element 4, and a test cell 1 was produced using a metal resin composite film for the outer package 5.
[0058]
(Test cell 2)
A test cell 2 was obtained by assembling in the same manner as in the test cell 1 except that the 3SDT was used instead of the 4SDT.
[0059]
(Test cell 3)
A test cell 3 was obtained in the same manner as in the test cell 1 except that the 2SDT was used instead of the 4SDT.
[0060]
Cyclic voltammetry (CV) measurement was performed on the test cells 1, 2 and 3. The upper and lower limits of the scanning potential were set to +1.5 to +3.5 V, and the measurement was performed by two cycles of linear scanning at a scanning speed of 10 mV / sec. The results are shown in FIGS.
[0061]
The test cells 1, 2 and 3 were subjected to constant current charging with a current of 0.1 mA and a final voltage of 4.0 V as batteries having a working electrode and a counter electrode as a positive electrode and a negative electrode, respectively, and then a current of 0.1 mA and a final voltage of 1 .5V constant current discharge was performed. As a result, the charge / discharge characteristics shown in FIGS.
[0062]
【The invention's effect】
As described above, by using the electrode material of the present invention, an electrode having a high capacity and excellent cycle characteristics can be obtained. In addition, since it can be processed from an active material soluble in a solvent into an active material insoluble in a solvent at the electrode preparation stage, it can be applied thinly, and its applicability to batteries requiring rate is immeasurable. Absent.
[Brief description of the drawings]
FIG. 1 is an external view of a test cell.
FIG. 2 is a cross-sectional view of a test cell.
FIG. 3 is a current-potential characteristic diagram of a test cell 1;
FIG. 4 is a charge / discharge characteristic diagram of a test cell 1;
FIG. 5 is a current-potential characteristic diagram of a test cell 2;
6 is a charge / discharge characteristic diagram of a test cell 2. FIG.
FIG. 7 is a current-potential characteristic diagram of the test cell 3;
FIG. 8 is a charge / discharge characteristic diagram of a test cell 3;
[Explanation of symbols]
1 Working Electrode 11 Working Electrode Material 12 Working Electrode Current Collector 2 Counter Electrode 21 Counter Electrode Material 22 Counter Electrode Current Collector 3 Electrolyte / Separator 4 Electrochemical Cell Element 5 Exterior Body 6 Terminal

Claims (5)

Organic sulfur having an alkene structure, R-S-S-R (R is a hydrocarbon, S is shown sulfur) in the electrolytic oxidation state possible electrolytic redox reaction with sulfur takes the structure represented by, in the inside of the molecule compounds of the electrochemical cell electrode material characterized by alkene having a polymeric sulfur compound formed by chemical crosslinking. The electrode material for an electrochemical cell according to claim 1, wherein the organic sulfur compound is represented by the following (Chemical Formula 1).
(However, at least one of R1, R2, R3 and R4 is an organic functional group containing sulfur capable of electrolytic redox reaction.) The (Formula 1), R1, R2, at least one of R3 or R4 is, o- mercaptophenyl, m- mercaptophenyl, claim characterized by having a p- mercaptophenyl or their metal salts 2 The electrode material for electrochemical cells as described. The (Formula 1), R1, R2, two or more of R3 or R4 is, o- mercaptophenyl, m- mercaptophenyl, claim characterized by having a p- mercaptophenyl or their metal salts 2 The electrode material for electrochemical cells as described. The electrochemical cell using the electrode material for electrochemical cells in any one of Claims 1-4 .