JP6606412B2 - Non-aqueous battery - Google Patents

Description

  The present invention relates to a positive electrode active material and a nonaqueous battery using a carbon sulfide polymer containing carbon and sulfur as constituent elements.

  In recent years, it is well known that there is an increasing need for new technologies that deal with energy and environmental problems. One of the promising technology candidates is the development of energy storage devices that are lighter and smaller in size and have dramatically higher output and large capacity. However, existing lithium ion secondary batteries and electric double layer capacitors have features such as relatively high storage capacity and a wide range of material selection. However, capacity and output are still not sufficient, and electrode materials and A fundamentally new approach to the power storage principle is desired.

In the case of a lithium ion secondary battery, lithium cobaltate is used as the positive electrode active material, but there is a theoretical limit to increasing the capacity and energy density. Recently, S _8, whose theoretical energy density is about one order of magnitude higher than that of lithium cobaltate, has attracted attention. However, elution of S into the electrolyte, lack of electronic conductivity, H ₂ S formation by reaction with water, etc. , various problems caused by the S ₈ alone has been pointed out as a positive electrode material.

Carbon sulfide polymers containing carbon and sulfur as constituent elements are attracting attention because of their high energy density. For example, Patent Document 1 below proposes using a carbon sulfide polymer represented by the general formula: (CS _w ) _p (w is 2.5 <w ≦ 50, p is 2 or more), 700 to It is disclosed to have a high energy density of 1350 mAh / g. Patent Document 2 below proposes using a carbon sulfide polymer represented by the general formula: (C ₂ S _w ) _p (w is 1 <w ≦ 100, p is 2 or more), and 700 to It is disclosed to have a high energy density of 1350 mAh / g. Patent Document 3 below proposes using a carbon sulfide polymer represented by the general formula: (CS _w ) _p (w is 1.4 to 1.6, p is 4 or more), 630 to It is disclosed to have a high energy density of 680 mAh / g.

Patent Document 4 listed below proposes using a carbon sulfide polymer represented by the general formula: (CS _w ) _p (w is 0.9 to 1.5, p is 4 or more) 550 It is disclosed to have a high energy density of ˜890 mAh / g.

Patent Document 5 below discloses a composite in which a carbon sulfide and carbon represented by the general formula: (CS _w ) _p (w is 0.9 to 2 and n is 4 or more) and carbon are combined. It is proposed to use and is disclosed to have a high energy density of 600-700 mAh / g.

Japanese National Patent Publication No. 11-514128 Japanese National Patent Publication No. 11-506799 JP 2003-123758 A JP 2002-154815 A JP 2003-163004 A

  Since carbon sulfide polymers have high energy density, they may become members of new electricity storage devices. However, there are very few reports on carbon sulfide polymers, and further development of carbon sulfide polymers useful as positive electrode active materials is also desirable. It is.

As a result of intensive studies in view of the above circumstances, the present inventors have found that when a complex obtained by mixing carbon disulfide and tertiary phosphine in a solvent is irradiated with ultraviolet rays or visible light, CS is released from the complex. release, the desorbed CS becomes reactive CS monomer polymerization reaction progresses, to generate the (CS) _n polymer, the (CS) _n polymer, the content of sulfur in the 72-74 wt%, polyacetylene And having the properties of sulfur alone. Further, the present inventors have found that a non-aqueous battery using the carbon sulfide polymer as a positive electrode active material becomes a high-capacity battery and completed the present invention.

  That is, an object of the present invention is to provide a positive electrode active material using a carbon sulfide polymer capable of achieving a high capacity of a nonaqueous battery and a high capacity nonaqueous battery.

The nonaqueous battery to be provided by the present invention includes a positive electrode using a carbon sulfide polymer represented by the general formula; (CS) _n (wherein n is 30 or more) as a positive electrode active material, a negative electrode, A non-aqueous battery having a non-aqueous electrolyte solution,
The carbon sulfide polymer includes a structural unit of polyacetylene in the main chain, has a sulfur content of 72 to 74% by mass, has an electric conductivity of 1.0 × 10 ⁻⁸ S / cm or more, and has a main chain. Is characterized by not containing a disulfide bond.

  By using the positive electrode active material containing the carbon sulfide polymer of the present invention, a high capacity non-aqueous battery can be provided.

4 is an absorbance spectrum of a complex obtained by reacting carbon disulfide and tri-n-butylphosphine in a molar ratio of 1: 1 in Reference Experiment 1. The figure which shows the relationship between the absorption spectrum intensity | strength of the liquid mixture in the vicinity of 360 nm when the addition amount of tri n-butylphosphine is changed with respect to carbon disulfide in the reference experiment 1, and the addition amount of tri n-butylphosphine. The figure which shows the relationship between the light absorption spectrum intensity | strength of the liquid mixture around 360 nm when the addition amount of triiso-butylphosphine is changed with respect to carbon disulfide with reference experiment 2, and the addition amount of triiso-butylphosphine. 1 is a schematic diagram of an experimental apparatus used in Example 1. FIG. The SEM photograph of the powder (carbon sulfide polymer) obtained on the glass plate in Example 1. (A) Magnification: 5 × 10 ³ , (b) Magnification: 2 × 10 ⁴ , (c) Magnification: 1 × 10 ⁴ , (d) Magnification: 3 × 10 ⁴ FIG. 3 is an IR spectrum diagram of the powder (carbon sulfide polymer) obtained in Example 1. IR spectrum diagram of (CS) _n , (CS ₂ ) _n polymers shown in the literature. FIG. 3 is an XPS spectrum diagram of C1s of the powder (carbon sulfide polymer) obtained in Example 1. The figure which shows the impedance measurement result of the carbon sulfide polymer obtained in Example 1, and the carbon sulfide polymer doped with iodine. The powder (carbon sulfide polymer) obtained in Example 1 is exposed to the atmosphere, in a mixed solvent of 1 part by mass of methanol and 1 part by mass of water, or in propylene carbonate in which 1 mol of LiClO ₄ is dissolved at 25 ° C. for 14 days. EPR spectrum before and after exposure.

Hereinafter, the present invention will be described based on preferred embodiments.
The positive electrode active material according to the present invention contains carbon and sulfur as constituent elements, and the sulfur content is 72 to 74% by mass, preferably 72.5 to 73.5% by mass, particularly preferably 72.6 to 73.1. One feature is that a carbon sulfide polymer represented by the general formula (1); (CS) _n (wherein n is 30 or more) is used.
Since the carbon sulfide polymer used in the present invention is hardly soluble in a solvent, it is difficult to measure its molecular weight, and an accurate value of n in the formula of the general formula (1) cannot be obtained. It is preferably 30 or more, and particularly preferably 35 to 70 from the viewpoint of resistance to organic solvents and heat resistance.

Carbon disulfide polymer used in the positive electrode active material of the present invention, in the infrared absorption spectrum analysis, at least near 1300~1500cm ^-1, 1200~1340cm around ^-1, 1100 cm around ^{-1, 940~510cm -1} and around 480 cm ^-1 It is preferable that vibration absorption peaks derived from C═C, C—C, C═S, C—S, and S—S bonds are observed in the vicinity.
In the present invention, the vicinity means a range of ± 2 cm ⁻¹ .

Further, the details of the structure of the carbon sulfide polymer are not clear because it is insoluble in the solvent and the analysis means is limited. However, the C1s spectrum in the X-ray photoelectron spectroscopic analysis has a binding energy of 288 eV and π electrons. Since a weak satellite peak based on the π-π ^* transition is observed, it is presumed to have a polyacetylene skeleton.
In the production method described later, as shown in the following reaction scheme (1), a scheme in which a monomer of CS (compound (a)) reacts as it is to synthesize a (CS) _n polymer, carbon disulfide ( CS ₂ ) forms a dimer (S = C = C = S) (compound (b)) as observed in the liquid phase photopolymerization, and the dimer reacts as it is, (CS) There is a scheme in which an _n polymer is synthesized, and the present inventors presume that a carbon sulfide polymer obtained by the production method contains a structural unit represented by the following (2-1).

Moreover, the electric conductivity of the carbon sulfide polymer used in the present invention is 1.0 × 10 ⁻⁸ S / cm or more at 25 ° C., preferably 1.0 × 10 ^{−7 to} 1.0 × 10 ⁻⁵ S / cm. There is also a feature of using a material having high electrical conductivity.
In the present invention, the electrical conductivity is obtained from a resistance value obtained from a Cole-Cole plot obtained by the AC impedance method.

  The carbon sulfide polymer having the above physical properties is produced by including a first step of preparing a mixed liquid in which carbon disulfide and tertiary phosphine are mixed, and then a second step of irradiating the mixed liquid with light. It is preferable that

  The first step is a step of obtaining a mixed solution containing the complex (compound (5)) by mixing carbon disulfide and tertiary phosphine (compound (4)) in a solvent according to the following reaction formula (1). It is. In this manufacturing method, by making it into a complex, in many cases, it has a maximum light absorption near 360 nm (± 10 nm).

  Examples of R in the formula of the tertiary phosphine (compound (4)) according to the first step include an alkyl group. Among these, C2-C10 alkyl groups, such as an ethyl group, n-propyl group, iso-propyl group, n-butyl group, iso-butyl group, n-pentyl group, n-hexyl group, n-octyl group. Tertiary phosphines having a hydrogen atom are preferred from the viewpoint that they easily form a complex with carbon disulfide, and an n-butyl group is particularly preferred.

  The mixing ratio of carbon disulfide and tertiary phosphine is such that the molar ratio of carbon disulfide to tertiary phosphine is approximately 1: 1, and the absorption spectrum between 360 nm (± 10 nm) is particularly high. Moreover, it is preferable from the viewpoint of avoiding mixing of unreacted raw materials.

  The solvent in the first step is not particularly limited as long as it can dissolve carbon disulfide, tertiary phosphine and complex, and is inert to carbon disulfide, tertiary phosphine and complex. . Examples thereof include aliphatic or aromatic hydrocarbons, halogenated hydrocarbons, aliphatic ethers, and alcohols. Examples of the aliphatic hydrocarbon include pentane, hexane, heptane, octane and the like. Examples of the aromatic hydrocarbon include benzene, toluene, xylene and the like. Examples of the halogenated hydrocarbon include chloroform, bromoform, methylene chloride, ethyl chloride, dichloroethane, chlorobenzene and the like. Examples of the aliphatic ether include diethyl ether, dipropyl ether, dibutyl ether, ethyl propyl ether, ethyl butyl ether and the like. Examples of the alcohol include methanol, ethanol, propanol, butanol and the like. These organic solvents may be used alone or as a mixture of two or more.

  In addition, the addition of carbon disulfide and tertiary phosphine to the solvent can stabilize the complex by adjusting the concentration of the resulting complex to 0.1 to 60 mol / L, preferably 1.0 to 50 mol / L. From the viewpoint of degree.

  The temperature at the time of mixing carbon disulfide and tertiary phosphine is preferably 0 to 50 ° C., more preferably 20 to 30 ° C., from the viewpoint of the boiling point of carbon disulfide and the thermal dissociation of the complex. Since the reaction proceeds quickly, a reaction time of about 1 minute is sufficient. Moreover, since the solution is discolored when the complex is formed, the completion of the reaction can be confirmed. For example, when tri-n-butylphosphine is used as the tertiary phosphine, when the complex is formed, the transparent mixed solution becomes a red mixed solution, so that the completion of the reaction can be easily visually observed.

  The second step is a step of obtaining the target carbon sulfide polymer by irradiating the mixed solution prepared in the first step with light.

  Based on the following reaction formula (2), the reaction related to the second step of this production method is that CS is released from the complex (compound (5)) by light irradiation and phosphine sulfide (compound (6)) is generated. To do. The detached CS becomes a reactive monomer and the polymerization reaction proceeds to produce a carbon sulfide polymer (compound (1)).

(In the formula, R and n are as defined above.)

  As the light source used in the second step, for example, an ultraviolet irradiation device having a xenon lamp, a pressurized mercury lamp, a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, a metal halide lamp, a carbon arc, etc. is used. Adjusted.

In this production method, the wavelength of light to be irradiated is preferably 320 to 400 nm, preferably 350 to 370 nm, from the viewpoint of the molar extinction coefficient of the complex. The light quantity is 10 to 30 W / cm ² , preferably 15 to 25 W / cm ² .

  As shown in the above reaction formula (1), the light irradiation temperature is 20 ° C. or less, preferably −40 to 10 ° C., because the complex formation reaction is a reversible reaction. However, it is preferable from the viewpoint of obtaining the target product in good yield.

  The irradiation time of light is not critical in this production method, and the reaction may be performed for a sufficient time until the carbon sulfide polymer is formed, and is usually 24 hours or longer, preferably 48 to 96 hours.

    After completion of the reaction, if necessary, a poor solvent such as hexane is added to the reaction solution and purified by redispersion, etc., followed by solid-liquid separation by a conventional method to recover the carbon sulfide polymer from the reaction solution. Furthermore, the target carbon sulfide polymer can be obtained by purification such as washing with a solvent or the like.

  In this production method, the obtained carbon sulfide polymer is subjected to heat treatment to remove low molecular weight substances having a molecular weight of less than 500, thereby further increasing the battery capacity of a non-aqueous battery using the carbon sulfide polymer as a positive electrode active material. Can be improved.

The heat treatment temperature is 200 to 500 ° C, preferably 250 to 400 ° C. The atmosphere for the heat treatment is preferably an inert gas atmosphere such as a nitrogen gas atmosphere or an argon atmosphere.
The time for performing the heat treatment is usually 1 hour or longer, preferably 2 to 5 hours.

The positive electrode active material according to the present invention can be used as a positive electrode active material for a non-aqueous battery to form a high capacity battery.
The basic configuration of the non-aqueous battery includes a positive electrode using a carbon sulfide polymer as a positive electrode active material, a negative electrode, and a non-aqueous electrolyte solution.

  The positive electrode according to the nonaqueous battery of the present invention is formed, for example, by applying and drying a positive electrode mixture on a positive electrode current collector. The positive electrode mixture includes a positive electrode active material, a conductive agent, a binder, and a filler that is added as necessary. In the nonaqueous battery of the present invention, the positive electrode active material containing the carbon sulfide polymer of the present invention is uniformly applied to the positive electrode.

  The content of the positive electrode active material contained in the positive electrode mixture according to the nonaqueous battery of the present invention is 20 to 100% by mass, preferably 25 to 98% by mass.

The positive electrode current collector according to the non-aqueous battery of the present invention is not particularly limited as long as it is an electronic conductor that does not cause a chemical change in the constituted battery. For example, stainless steel, nickel, nickel alloy, aluminum In addition, titanium, baked carbon, aluminum or stainless steel having a surface treated with carbon, nickel, titanium, or silver, or nickel sulfide such as NiS, Ni ₂ S ₂ , or NiS ₂ can be used. The surface of these materials may be oxidized and used, or the current collector surface may be provided with irregularities by surface treatment. Examples of the current collector include foils, films, sheets, nets, punched ones, lath bodies, porous bodies, foam bodies, fiber groups, nonwoven fabric molded bodies, and the like. The thickness of the current collector is not particularly limited, but is preferably 1 to 500 μm.

  The conductive agent according to the non-aqueous battery of the present invention is not particularly limited as long as it is an electron conductive material that does not cause a chemical change in the constituted battery. For example, graphite such as natural graphite and artificial graphite, carbon black, acetylene black, ketjen black, channel black, furnace black, lamp black, carbon black such as thermal black, conductive fibers such as carbon fiber and metal fiber, Examples include metal powders such as carbon fluoride, aluminum and nickel powder, conductive whiskers such as zinc oxide and potassium titanate, conductive metal oxides such as titanium oxide, and conductive materials such as polyphenylene derivatives. Examples of graphite include scaly graphite, scaly graphite, and earthy graphite. These can be used alone or in combination of two or more. The compounding ratio of the conductive agent is 1 to 60% by mass, preferably 2 to 50% by mass in the positive electrode mixture.

  Examples of the binder according to the nonaqueous battery of the present invention include starch, polyvinylidene fluoride, polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, regenerated cellulose, diacetyl cellulose, polyvinyl pyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, Ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene butadiene rubber, fluoro rubber, tetrafluoroethylene-hexafluoroethylene copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-perfluoro Alkyl vinyl ether copolymer, vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-chlorotrifluoroethylene copolymer , Ethylene-tetrafluoroethylene copolymer, polychlorotrifluoroethylene, vinylidene fluoride-pentafluoropropylene copolymer, propylene-tetrafluoroethylene copolymer, ethylene-chlorotrifluoroethylene copolymer, vinylidene fluoride- Hexafluoropropylene-tetrafluoroethylene copolymer, vinylidene fluoride-perfluoromethyl vinyl ether-tetrafluoroethylene copolymer, ethylene-acrylic acid copolymer or its (Na +) ionic crosslinked product, ethylene-methacrylic acid copolymer Copolymer or its (Na +) ion crosslinked product, ethylene-methyl acrylate copolymer or its (Na +) ion crosslinked product, ethylene-methyl methacrylate copolymer or its (Na +) ion crosslinked product, polyethylene oxide, etc. Many S, thermoplastic resins, polymers having rubber elasticity, and these may be used individually or in combination. In addition, when using the compound containing the functional group which reacts with lithium like a polysaccharide, it is preferable to add the compound like an isocyanate group and to deactivate the functional group, for example. The blending ratio of the binder is 1 to 50% by mass, preferably 5 to 15% by mass in the positive electrode mixture.

  The filler relating to the nonaqueous battery of the present invention suppresses the volume expansion of the positive electrode in the positive electrode mixture, and is added as necessary. As the filler, any fibrous material can be used as long as it does not cause a chemical change in the constructed battery. For example, olefinic polymers such as polypropylene and polyethylene, and fibers such as glass and carbon are used. Although the addition amount of a filler is not specifically limited, 0-30 mass% is preferable in a positive mix.

  The negative electrode according to the nonaqueous battery of the present invention is formed by applying and drying a negative electrode material on a negative electrode current collector. The negative electrode current collector according to the non-aqueous battery of the present invention is not particularly limited as long as it is an electronic conductor that does not cause a chemical change in the constructed battery. For example, stainless steel, nickel, copper, titanium, Examples include aluminum, calcined carbon, copper or stainless steel having a surface treated with carbon, nickel, titanium, silver, and an aluminum-cadmium alloy. Further, the surface of these materials may be used after being oxidized, or the surface of the current collector may be provided with irregularities by surface treatment. Examples of the current collector include foils, films, sheets, nets, punched ones, lath bodies, porous bodies, foam bodies, fiber groups, nonwoven fabric molded bodies, and the like. The thickness of the current collector is not particularly limited, but is preferably 1 to 500 μm.

Although it does not restrict | limit especially as a negative electrode material which concerns on the nonaqueous battery of this invention, For example, a carbonaceous material, a metal complex oxide, lithium metal, a lithium alloy, a silicon-type alloy, a tin-type alloy, a metal oxide , Conductive polymer, chalcogen compound, Li—Co—Ni-based material, Li ₄ Ti ₅ O _{12 and the} like. Examples of the carbonaceous material include non-graphitizable carbon materials and graphite-based carbon materials. Examples of the metal composite oxide include Sn _p (M1) _1-p (M2) _{q Or} (wherein M1 represents one or more elements selected from Mn, Fe, Pb and Ge, and M2 represents Al. , B, P, Si, one or more elements selected from Group 1, Group 2, Group 3 of the periodic table and halogen elements, 0 <p ≦ 1, 1 ≦ q ≦ 3, 1 ≦ r ≦ shows a _{8.), Li t Fe 2} O 3 (0 ≦ t ≦ 1), Li t WO 2 (0 ≦ t ≦ 1) compound of the like. As the metal _{oxide, GeO, GeO 2, SnO,} SnO 2, PbO, PbO 2, Pb 2 O 3, Pb 3 O 4, Sb 2 O 3, Sb 2 O 4, Sb 2 O 5, Bi 2 O 3 Bi ₂ O ₄ , Bi ₂ O ₅ , or silicon oxide represented by the general formula SiO _x (0.5 ≦ x <1.6). Examples of the conductive polymer include polyacetylene and poly-p-phenylene.

  As the separator according to the nonaqueous battery of the present invention, an insulating thin film having a large ion permeability and a predetermined mechanical strength is used. Sheets and non-woven fabrics made of olefin polymers such as polypropylene, glass fibers or polyethylene are used because of their organic solvent resistance and hydrophobicity. The pore diameter of the separator may be in a range generally useful for batteries, and is, for example, 0.01 to 10 μm. The thickness of the separator may be in a range for a general battery, for example, 5 to 300 μm. When a solid electrolyte such as a polymer is used as the electrolyte described later, the solid electrolyte may also serve as a separator.

  The nonaqueous electrolyte containing a lithium salt according to the nonaqueous battery of the present invention is composed of a nonaqueous electrolyte and a lithium salt. As the nonaqueous electrolyte according to the nonaqueous battery of the present invention, a nonaqueous electrolytic solution, an organic solid electrolyte, or an inorganic solid electrolyte is used. Examples of the non-aqueous electrolyte include N-methyl-2-pyrrolidinone, propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, γ-butyrolactone, 1,2-dimethoxyethane, tetrahydroxyfuran, and 2-methyl. Tetrahydrofuran, dimethyl sulfoxide, 1,3-dioxolane, formamide, dimethylformamide, dioxolane, acetonitrile, nitromethane, methyl formate, methyl acetate, phosphate triester, trimethoxymethane, dioxolane derivative, sulfolane, methylsulfolane, 3-methyl -2-oxazolidinone, 1,3-dimethyl-2-imidazolidinone, propylene carbonate derivative, tetrahydrofuran derivative, diethyl ether, 1,3- Ropansaruton, methyl propionate, and a solvent obtained by mixing one or more aprotic organic solvents such as ethyl propionate.

  Examples of the organic solid electrolyte according to the nonaqueous battery of the present invention include polyethylene derivatives, polyethylene oxide derivatives or polymers containing the same, polypropylene oxide derivatives or polymers containing the same, phosphate ester polymers, polyphosphazenes, polyaziridines, and polyethylene sulfides. , A polymer containing an ionic dissociation group such as polyvinyl alcohol, polyvinylidene fluoride, polyhexafluoropropylene, a mixture of a polymer containing an ionic dissociation group and the non-aqueous electrolyte, and the like.

As the inorganic solid electrolyte according to the nonaqueous battery of the present invention, Li nitride, halide, oxyacid salt, sulfide, and the like can be used. For example, Li ₃ N, LiI, Li ₅ NI ₂ , Li _{3 N-LiI-LiOH, LiSiO 4} , LiSiO 4 -LiI-LiOH, Li 2 SiS 3, Li 4 SiO 4, Li 4 SiO 4 -LiI-LiOH, P 2 S 5, Li 2 S or Li ₂ S-P _{2 S 5, Li 2 S-SiS} 2, Li 2 S-GeS 2, Li 2 S-Ga 2 S 3, Li 2 S-B 2 S 3, Li 2 S-P 2 S 5 -X, Li 2 S- _{SiS 2 -X, Li 2 S-} GeS 2 -X, Li 2 S-Ga 2 S 3 -X, Li 2 S-B 2 S 3 -X, ( wherein, X is LiI, B ₂ S _3, or And at least one selected from Al ₂ S ₃ ).

Further, when the inorganic solid electrolyte is amorphous (glass), lithium phosphate (Li ₃ PO ₄ ), lithium oxide (Li ₂ O), lithium sulfate (Li ₂ SO ₄ ), phosphorus oxide (P ₂ O ₅₎ ), Compounds containing oxygen such as lithium borate (Li ₃ BO ₃ ), Li ₃ PO _4-u N _{2u / 3} (u is 0 <u <4), Li ₄ SiO _4-u N _{2u / 3} (u is Nitrogen such as 0 <u <4), Li ₄ GeO _4-u N _{2u / 3} (u is 0 <u <4), Li ₃ BO _3-u N _{2u / 3} (u is 0 <u <3) The compound to be contained can be contained in the inorganic solid electrolyte. By adding the compound containing oxygen or the compound containing nitrogen, the gap between the formed amorphous skeletons can be widened, the hindrance to movement of lithium ions can be reduced, and ion conductivity can be further improved.

As the lithium salt related to the non-aqueous battery of the present invention, those that dissolve in the non-aqueous electrolyte are used. For example, LiCl, LiBr, LiI, LiClO ₄ , LiBF ₄ , LiB ₁₀ Cl ₁₀ , LiPF ₆ , LiCF ₃ SO ₃ , LiCF ₃ CO ₂ , LiAsF ₆ , LiSbF ₆ , LiB ₁₀ Cl ₁₀ , LiAlCl ₄ , CH ₃ SO ₃ Li, CF ₃ SO ₃ Li, (CF ₃ SO ₂ ) ₂ NLi, chloroborane lithium, lower aliphatic carboxyl Examples thereof include salts obtained by mixing one or more of lithium acid lithium, lithium tetraphenylborate, imides and the like.

Moreover, the compound shown below can be added to a nonaqueous electrolyte for the purpose of improving discharge, a charge characteristic, and a flame retardance. For example, pyridine, triethyl phosphite, triethanolamine, cyclic ether, ethylenediamine, n-glyme, hexaphosphoric acid triamide, nitrobenzene derivative, sulfur, quinoneimine dye, N-substituted oxazolidinone and N, N-substituted imidazolidine, ethylene glycol dialkyl ether , Ammonium salt, polyethylene glycol, pyrrole, 2-methoxyethanol, aluminum trichloride, conductive polymer electrode active material monomer, triethylenephosphonamide, trialkylphosphine, morpholine, aryl compounds with carbonyl group, hexamethylphosphine Holic triamide and 4-alkylmorpholine, bicyclic tertiary amine, oil, phosphonium salt and tertiary sulfonium salt, phosphazene, carbonate, Li ₂ S _And lithium sulfide of polysulfide such as ₈ . In order to make the electrolyte nonflammable, a halogen-containing solvent such as carbon tetrachloride or ethylene trifluoride can be included in the electrolyte. In addition, carbon dioxide gas can be included in the electrolytic solution in order to make it suitable for high-temperature storage.

  The non-aqueous battery of the present invention is a high-capacity non-aqueous battery, and the shape of the battery may be any shape such as a button, a sheet, a cylinder, a corner, or a coin type.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these Examples.

{Reference Experiment 1}
A flask was charged with 10 g of ethanol as a solvent, and tri-n-butylphosphine and carbon disulfide were added thereto at room temperature so that the complex concentration was 1.1 × 10 ⁻³ mol. Immediately after the addition, the mixture turned red. The absorbance of this red mixture was measured. The absorbance spectrum is shown in FIG.
The flask is charged with 10 g of ethanol as a solvent, and then the molar ratio of tri-n-butylphosphine to the total number of moles of tri-n-butylphosphine added and 0.08 g of carbon disulfide (1.1 × 10 ⁻³ mol) is set to 0 to 1. The mixture was added at room temperature, and the absorbance of the mixture obtained after about 1 minute was measured. The absorbance at 360 nm is shown in FIG.
As apparent from FIG. 2, a complex (complex) is formed with carbon disulfide and tri-n-butylphosphine at a molar ratio of 1: 1, and carbon disulfide and tri-n-butylphosphine with a molar ratio. At 1: 1, the absorption spectrum maximum was observed.

{Reference Experiment 2}
The absorbance of the mixed solution was measured in the same manner as in Reference Experiment 1 except that triiso-butylphosphine was used instead of tri-n-butylphosphine.
As is apparent from FIG. 3, a complex is formed with carbon disulfide and tri-n-butylphosphine at a molar ratio of 1: 1, and carbon disulfide and tri-n-butylphosphine with a molar ratio of 1: 1. In this case, the maximum of the absorbance spectrum was observed.

{Example 1}
The following reaction was performed using the experimental apparatus shown in FIG.
Argon purged flask dichloromethane 4.5ml was bubbled with dehydration and nitrogen gas, tri n- butylphosphine 4.6g (2.3 × 10 ^-2 mol), carbon disulfide 1.7g (2.3 × 10 ^{- 2} mol) was weighed with a microsyringe to prepare a red mixed solution having a complex concentration of 2.0M.
Next, the red mixed liquid was put on a refrigerant (methanol) at −30 ° C., and a glass plate was suspended inside the flask and fixed.
From the upper part of the flask, the ultra high pressure mercury lamp (USHIO Corporation, light source device SX-UI501HQ type, power supply device BA-H501 type) is used only with a cold mirror, and 350 to 370 nm ultraviolet light and visible light are emitted with a light amount of 18 W / Irradiated at cm ² for 96 hours.

(SEM observation)
After completion of the light irradiation, the suspended glass plate was collected and observed with a scanning electron microscope (SEM). The SEM photograph is shown in FIG.

  From (a) of FIG. 5, it was confirmed that a carbon sulfide polymer thin film was formed. Further, when (b), (c), and (d) are enlarged from (a), it can be seen that the structure is a collection of particles. From this, it was found that fine aerosols gathered hierarchically to form a hierarchical structure, and a carbon sulfide polymer thin film was formed on the surface of the glass plate.

(Elemental analysis)
The powder on the wall of the flask was collected, washed with distilled water, and dried to obtain a powder. This powder was subjected to elemental analysis by X-ray photoelectron spectroscopy. As a result, it was confirmed that C: 27 mass%, S: 73 mass%, H: 0 mass%, N: 0 mass%, P: 0 mass%, and the molar ratio of C and S was 1: 1. It was.

(Infrared absorption (IR) spectrum analysis)
The powder on the wall of the flask was collected, washed with distilled water, and dried to obtain a powder. The infrared absorption spectrum of this powder was measured with a Fourier transform infrared spectrophotometer (JASCO Corporation, FT / IR 4200 type). The result is shown in FIG.
Infrared light disclosed in (CS) _n and (CS ₂ ) _n literature (J. Am. Chem. Soc., 2001, pp. 1199-1207) obtained by short wavelength irradiation of carbon disulfide. The absorption spectrum is shown in FIG.

The obtained powder showed absorption at 1100 cm ⁻¹ in the vicinity of the peak derived from thiocarbonyl (C═S) of (CS) _n and (CS ₂ ) _n shown in the literature. Moreover, since the spectrum shape was very similar, it was found that the obtained powder was a compound similar in structure to the (CS) _n polymer disclosed in the literature.

1100cm ^-1 1300~1500cm ^-1 Besides, 1200~1340cm ^-1, 940~510cm ^-1, to 480 cm ^-1, respectively C = C, C-C, C-S, vibration absorption derived from S-S bond The peak was also observed.

Elemental analysis and infrared absorption spectrum measurement confirmed that the obtained powder was a sulfurized carbon polymer represented by the general formula: (CS) _n (wherein n represents 30 or more).

(X-ray photoelectron spectroscopy)
The powder on the wall of the flask was collected, washed with distilled water, and dried to obtain a powder. This powder was subjected to X-ray photoelectron spectroscopic analysis. The result is shown in FIG.
Measurement equipment and conditions are as follows.
Measuring equipment: SURFACE SCIENCE INSTRUMENTS SSX-100,
Measurement conditions; energy range: 0 to 1100 eV, measurement temperature: 25 ° C
From the results of FIG. 8, it can be inferred that the C1s spectrum has a polyacetylene skeleton in which a weak satellite peak based on a π-π ^* transition of π electrons is observed at a binding energy of 288 eV.

Furthermore, in this production method, as shown in the above-mentioned reaction scheme (1), a scheme in which a monomer of CS (compound (a)) reacts as it is to synthesize a (CS) _n polymer, carbon disulfide, A dimer (S = C = C = S) (compound (b)) is formed as observed in the liquid polymerization of (CS ₂ ), and the dimer reacts as it is. ) There is a scheme in which an _n polymer is synthesized, and the present inventors presume that the sulfurized carbon polymer obtained by this production method contains a structural unit represented by the following general formula (2-1). .

(Measurement of electrical conductivity)
The powder on the wall of the flask was collected, washed with distilled water, and dried to obtain a powder. Using this powder, a thin film was formed on a comb-shaped electrode cell, and impedance was measured by an AC impedance method using an impedance / gain phase analyzer (Toyo Technica Co., 1260, 1296 type) (frequency range: 5.0 MHz to 0.001). 1 Hz, AC level: 1 Vms, measurement temperature 25 ° C.). FIG. 9A shows a Cole-Cole plot. The interdigital electrode cell was measured using a cell electrode having a distance between electrodes of 50 μm, a width of 50 μm, and a cell constant of 5.55 × 10 ⁻³ . FIG. 9B is a plot of | Z | versus frequency, and FIG. 9C is a plot of theta versus frequency. Here, | Z | means the logarithm of the absolute value of impedance, and theta means the phase difference (degree).
Focusing on the frequency dependence, since it responds on the high frequency side of 10 ⁻⁶ , it became clear that the carriers responsible for conduction are light particles such as electrons and holes. Further, the Cole-Cole plot in FIG. 9A depicts a semicircle. When considering the bulk electrical characteristics of a general organic compound, a semicircle is drawn assuming a parallel circuit of a capacitor component and a resistance component. The intersection of the semicircle and the real impedance part is reflected in the impedance. From this result, the resistance value (R) of the obtained powder was 2.9 × 10 ⁴ Ω. According to the following formula, the electric conductivity σ (S / cm) was calculated from the resistance value (R) based on the thickness (L) of the sample and the electrode area (S). As a result, 2.0 × 10 ⁻⁷ S / cm Met.
R = ρ (L / S)
σ = 1 / ρ

Moreover, the impedance measurement was similarly performed about what obtained the powder obtained for supporting pi-electron conjugated structure, and made iodine contact with chemical vapor. The result is also shown in FIG. Similarly, the electrical conductivity was determined to be 1.1 × 10 ⁻⁶ S / cm.

  From these results, it was found that the carbon sulfide polymer obtained this time has a π-electron conjugated structure and high electrical conductivity.

<Evaluation of stability>
Collect the powder on the wall of the flask, wash with distilled water, and dry the carbon sulfide polymer obtained in the atmosphere, in a mixed solvent of 1 part by mass of methanol and 1 part by mass of water, or 1 mol of LiClO _4. Each was exposed to dissolved propylene carbonate for 14 days at 25 ° C., and electron paramagnetic resonance (EPR) analysis was performed before and after exposure. The result is shown in FIG.
Measurement equipment and conditions are as follows.
Measuring device: JES-RE3X manufactured by JEOL JEOL,
Measurement conditions: Power: 4 mW, Field and Sweep Width: 326 ± 25 mT, Sweep Time: 1 min, Modulation Frequency and Amplitude: 100 / 0.1 KHz / mT, Receiver Gain: 5 × 100, Time Constant: 0.1 sec
From the results of FIG. 10, there was almost no change in the EPR spectrum after 14 days. Therefore, it can be seen that the carbon sulfide polymer used in the present invention is a stable compound in air, in a solvent, or in an electrolyte solution.

<Evaluation of battery performance>
(1) Preparation of coin-type cell The powder on the wall surface of the flask is collected, washed with distilled water, and dried to obtain 30% by mass of a carbon sulfide polymer (positive electrode active material), ketjen black (conductive agent) 45 A kneading paste was prepared by mixing 5% by mass and 25% by mass of polytetrafluoroethylene (binder) to obtain a positive electrode agent, which was dispersed in N-methyl-2-pyrrolidinone. The kneaded paste was applied to an aluminum foil, dried, pressed, and punched into a disk having a diameter of 12 mm to obtain a positive electrode plate.
Using this positive electrode plate, a lithium secondary battery was manufactured using each member such as a separator, a negative electrode, a positive electrode, a current collector plate, a mounting bracket, an external terminal, and an electrolytic solution. Of these, a metal lithium foil was used for the negative electrode, and Li (CF ₃ SO ₂ ) ₂ N (1 mol) dissolved in 1 liter of 9: 1 kneaded liquid of diethoxyethane and ethylene carbonate was used for the electrolyte. .
(2) Battery performance evaluation The produced coin-type battery was placed in a thermostatic layer maintained at 25 ° C., and 0.1 mA constant current discharging and constant current charging were performed in the region from 3.0 V to 1.0 V. . This discharge and charge were repeated as 50 cycles for 50 cycles. Table 1 shows the discharge capacity at the beginning of the cycle, the discharge capacity at the 5th cycle, the 10th cycle, and the 50th cycle.

{Example 2}
A coin-type battery was prepared in the same manner as in Example 1 except that 70% by mass of the carbon sulfide polymer obtained in Example 1, 20% by mass of Ketjen Black, and 10% by mass of polytetrafluoroethylene were mixed to obtain a positive electrode agent. The battery was prepared and evaluated in the same manner as in Example 1.

{Example 3}
The powder attached to the wall of the flask in Example 1 was collected, washed with distilled water, and then the dried powder was heat treated at 300 ° C. for 3 hours in an argon atmosphere to obtain a carbon sulfide polymer.
Next, a coin-type battery was prepared in the same manner as in Example 1, and the battery was evaluated in the same manner as in Example 1.

  The discharge capacity is a value per unit weight (g) of the carbon sulfide polymer, but the amount of the conductive agent used can be reduced by the conductivity of the carbon sulfide polymer. Therefore, considering the discharge capacity per unit weight of the entire positive electrode material, it can be seen that the performance of the carbon sulfide polymer as a positive electrode active material is high.

Claims (2)

A non-aqueous battery having a positive electrode using a carbon sulfide polymer represented by the general formula: (CS) _n (wherein n is 30 or more), a negative electrode, and a non-aqueous electrolyte solution. And
The carbon sulfide polymer includes a structural unit of polyacetylene in the main chain, has a sulfur content of 72 to 74% by mass, has an electric conductivity of 1.0 × 10 ⁻⁸ S / cm or more, and has a main chain. Does not contain a disulfide bond. In carbon disulfide polymers infrared absorption spectrum analysis, at least near 1300~1500cm ^-1, 1200~1340cm around ^-1, 1100 cm around ^-1, around 510～940Cm ^-1 and near 480 cm ^-1, respectively C = C, C The non-aqueous battery according to claim 1, having vibration absorption peaks derived from —C, C═S, C—S, and S—S bonds.