JP7084587B2 - Polymers, electrode active materials and secondary batteries - Google Patents

Description

Application of Article 30, Paragraph 2 of the Patent Act On June 18, 2018, http: // ispe-16. jp / _img / program / Abstract_Book_Data_for_web_rev. Published in the proceedings of The 16th International Symposium on Polymer Electrolytes through pdf On June 26, 2018, The 16th International Symposium on Polymer / October 24, 2018, published in Heisei 10 / Electrolyte. spsj. or. jp / ipc2018 / tentative_program. Only the title is released in the provisional proceedings of The 12th SPSJ International Polymer Conference through pdf.

The present invention relates to polymers, particularly polymers obtained by condensation polymerization of 1,2,4,5-tetraamino-p-benzoquinone and triquinoyl hydrate, electrode active materials and secondary batteries.

An organic secondary battery is a battery that uses an organic charge storage material as an electrode active material in a secondary battery, and has features such as high rate characteristics, high capacity retention rate associated with charge / discharge cycles, lightweight thin film, and flexibility. , Is getting a lot of attention. As the organic charge storage material, a compound containing a nitroxy radical group is often used (Non-Patent Documents 1 and 2 and Patent Document 1), but an organic sulfur polymer (Non-Patent Documents 3 and 4) and a quinoid polymer (Patent Document 1). 2), quinoid-based materials (Patent Documents 3, 4, 5), dione-based materials (Patent Document 6), rubianic acid-based materials (Patent Document 7), and the like have also been reported.

Further, in recent years, by using it in coexistence with an inorganic electrode active material, the capacity and voltage retention rate (hereinafter referred to as rate characteristics) of a lithium ion battery during high-speed charging / discharging are improved, and the capacity retention rate during charging / discharging cycle (hereinafter referred to as “rate characteristic”) is improved. It has been shown that improvement is possible (referred to as cycle characteristics) (Non-Patent Document 5), and its applications and methods are expanding.

Japanese Unexamined Patent Publication No. 2002-117852 Japanese Unexamined Patent Publication No. 2009-217992 Japanese Unexamined Patent Publication No. 2010-44882 Japanese Unexamined Patent Publication No. 2010-5923 Japanese Unexamined Patent Publication No. 2010-80343 Japanese Unexamined Patent Publication No. 2010-212152 Japanese Unexamined Patent Publication No. 2008-147015

Chem. Phys. Lett., Vol. 359, pp. 351-354, 2002 Electrochem. Soc. Interface, vol. 14, pp. 32-36, 2005 J. Electrochem. Soc., Vol. 136, pp. 661-664, 1989 Electrochimica Acta, vol. 46, pp. 2305-2312, 2001 Scientific Reports, vol. 4, pp. 4315-4321, 2014

However, a battery using a nitroxy radical-based charge storage material as an electrode active material has a smaller charge storage capacity than that using an inorganic electrode active material, and can use a high-capacity organic charge storage material such as an organic sulfur polymer. When used, there are problems that the electrochemical stability is low, sufficient cycle characteristics cannot be obtained, and the voltage is low. Further, in other organic charge storage materials, when used alone as an electrode active material or in combination with an inorganic electrode active material, in addition to the above-mentioned problems, elution resistance to an electrolytic solution and sufficient ion inflow / outflow are possible. Due to lack of swelling property, ionic conductivity, binding property with an inorganic electrode active material and a current collector, etc., sufficient performance may not be obtained as a secondary battery, particularly a lithium ion battery.

The present invention has been made in view of such circumstances, and when used as an electrode active material, has a charge storage property that can provide a high-performance battery having high capacity, high rate characteristics and high cycle characteristics. The purpose is to provide the material to have.

As a result of diligent studies to achieve the above object, the present inventors have obtained a case where a specific polymer having a polymer having an azaanthraquinone skeleton functions as a charge storage material and is used as an electrode active material. The present invention has been completed by finding that a secondary battery exhibiting high capacity, high rate characteristics and high cycle characteristics can be provided by overcoming the above problems.

２． 上記式（１）～（３）で表される繰り返し単位のうち、式（２）及び（３）で表される繰り返し単位から選ばれる少なくとも１種を必ず含む１のポリマー。
３． １又は２のポリマーからなる電荷貯蔵材料。
４． ３の電荷貯蔵材料を含む電極活物質。
５． ４の電極活物質、及び溶媒を含む電極スラリー。
６． ４の電極活物質を含む薄膜。
７． ５の電極スラリーから得られる薄膜。
８． ４の電極活物質を含む電極。
９． ６又は７の薄膜を含む電極。
１０． ８又は９の電極を含む二次電池。
１１． ８又は９の電極を含むリチウムイオン電池。
１２． 電解質の濃度が０．００１～２ｍｏｌ／Ｌである電解液を含む１１のリチウムイオン二次電池。
１３． イオン伝導度が１０^-7～１０^-3Ｓ／ｃｍである固体電解質を含む全固体電池である１０の二次電池。
１４． １，２，４，５－テトラアミノ－ｐ－ベンゾキノンとトリキノイル水和物とを縮合重合させることを含む１のポリマーの製造方法。 That is, the present invention provides the following charge storage materials, electrode active materials, and secondary batteries.
1. 1. A polymer having an azaanthraquinone skeleton and comprising at least one selected from repeating units represented by the following formulas (1) to (3).

2. 2. One polymer that always contains at least one selected from the repeating units represented by the formulas (2) and (3) among the repeating units represented by the above formulas (1) to (3).
3. 3. A charge storage material consisting of 1 or 2 polymers.
4. Electrode active material containing 3 charge storage materials.
5. An electrode slurry containing the electrode active material of No. 4 and a solvent.
6. A thin film containing the electrode active material of 4.
7. A thin film obtained from the electrode slurry of 5.
8. An electrode containing the electrode active material of 4.
9. An electrode containing a thin film of 6 or 7.
10. A secondary battery containing 8 or 9 electrodes.
11. A lithium ion battery comprising 8 or 9 electrodes.
12. 11 lithium ion secondary batteries containing an electrolytic solution having an electrolyte concentration of 0.001 to 2 mol / L.
13. A secondary battery of 10 which is an all-solid-state battery containing a solid electrolyte having an ionic conductivity of 10 ^-7 to 10 ^-3 S / cm.
14. 1. A method for producing a polymer, which comprises polycondensation polymerizing 1,2,4,5-tetraamino-p-benzoquinone and triquinoyl hydrate.

The polymer according to the present invention has an azaanthraquinone skeleton as a main component of charge storage, and has high electrochemical stability because the generated anion radicals are stabilized by a continuous pyridine fused ring structure, and is useful as a charge storage material. Is.

By using the above polymer as an electrode active material, it is possible to manufacture a secondary battery having high capacity, high rate characteristics and high cycle characteristics. The above polymer is particularly suitable as an electrode active material for a lithium ion battery. In a general secondary battery, an inorganic material or a carbon material is used as an electrode active material, but either the positive electrode or the negative electrode can be replaced with an electrode containing the charge storage material of the present invention. It can also be used in combination with an inorganic material-based or carbon material-based electrode active material.

FIG. 1 (a) is a diagram showing a part of the ¹ H-NMR spectrum of 1,2,4,5-tetraamino-p-benzoquinone of Synthesis Example 1, and FIG. 1 (b) is a polymer of Example 1. It is a figure which shows a part of ¹ H-NMR spectrum of A. It is a schematic diagram of the beaker cell produced in the Example. It is a cyclic voltamogram of the thin film electrode produced in Example 2. It is a graph which shows the measurement result of the potential difference with the reference electrode at the time of changing the charge / discharge capacity in the lithium ion battery produced in Example 3. FIG. It is a figure which shows the charge / discharge cycle characteristic of the lithium ion battery produced in Example 3. FIG. It is a graph which shows the measurement result of the potential difference with the reference electrode at the time of changing the charge / discharge capacity in the lithium ion battery produced in Example 4. It is a graph which shows the measurement result of the potential difference from the reference electrode at the time of changing the charge / discharge capacity in the polymer lithium all-solid-state battery produced in Example 5.

[polymer]
The polymer of the present invention contains at least one selected from the repeating units represented by the following formulas (1) to (3).

The structure of the polymer as a whole differs depending on the content ratio of the repeating units represented by the formulas (1) to (3). For example, when a large number of repeating units represented by the formulas (1) and (2) are contained, the polymer becomes a ladder type polymer, and the higher the ratio of the repeating units represented by the formula (1), the higher the linearity. It becomes a polymer. When the repeating unit represented by the formula (3) is contained, the polymer is a branched polymer containing a branched structure, and the higher the ratio of the repeating units, the higher the branched polymer.

In the present invention, the polymer always contains at least one selected from the repeating units represented by the formulas (2) and (3) among the repeating units represented by the formulas (1) to (3). Is more preferable. Further, from the viewpoint of electrochemical stability, a ladder type polymer having a high content ratio of a repeating unit represented by the formula (1) or a highly branched polymer having a high content ratio of a repeating unit represented by the formula (3). Is preferable.

The polymer preferably contains, for example, a partial structure derived from an oligomer as shown in the following formulas (4-1) to (4-11), but is not limited thereto.

The polymer can be synthesized, for example, by condensation polymerization of 1,2,4,5-tetraamino-p-benzoquinone and triquinoyl hydrate in polyphosphoric acid. It should be noted that 1,2,4,5-tetraamino-p-benzoquinone can be synthesized, for example, with reference to the method described in US Pat. No. 3,017,725. As the triquinoyl hydrate, a commercially available product can be used, and examples thereof include triquinoyl hydrate (manufactured by Tokyo Chemical Industry Co., Ltd.).

The charging ratio (molar ratio) of 1,2,4,5-tetraamino-p-benzoquinone and triquinoyl hydrate cannot be unconditionally specified because it is appropriately determined in consideration of the target structure, molecular weight, etc. In the case of obtaining a ladder type polymer, it is preferable that the number of moles of both components is about the same. Specifically, it is preferable that 1,2,4,5-tetraamino-p-benzoquinone is 0.80 to 1.20 mol, and 0.90 to 1.20 mol, per 1 mol of triquinoyl hydrate. It is more preferably 10 mol, and even more preferably 0.95 to 1.05 mol.

In addition, when obtaining a branched polymer, it is preferable to use an excess amount of 1,2,4,5-tetraamino-p-benzoquinone with respect to triquinoyl hydrate. Specifically, the amount of 1,2,4,5-tetraamino-p-benzoquinone is preferably more than 1.20 mol, and 1.30 to 2.20 mol is preferable with respect to 1 mol of triquinoyl hydrate. More preferably, 1.40 to 2.20 mol is even more preferable, 1.50 to 2.20 mol is further preferable, and in particular, 1.50 or more makes it easier to obtain a highly branched polymer. By setting the amount of 1,2,4,5-tetraamino-p-benzoquinone to be used below the upper limit of the above range, amino acids derived from 1,2,4,5-tetraamino-p-benzoquinone at the terminal ends. Low molecular weight compounds having a group are not excessively produced, and it is easy to obtain a polymer having a desired molecular weight.

In the above polymerization reaction, polyphosphoric acid, sulfuric acid, diphosphorus pentoxide and the like can be used as the solvent. In the present invention, polyphosphoric acid can be preferably used. The amount of the solvent used is preferably about 15 to 30 equivalents with respect to 1 equivalent of tetraaminobenzoquinone (for example, 2 to 5 mL of solvent with respect to 500 mg of tetraaminobenzoquinone).

The reaction temperature can be usually set to about 20 to 100 ° C, preferably about 75 to 100 ° C, although normal conditions can be adopted and is not particularly limited. As for the reaction time, ordinary conditions can be adopted, and the reaction time is not particularly limited, but is usually about 1 to 1,000 hours, preferably 24 to 72 hours.

The weight average molecular weight (Mw) of the polymer of the present invention is preferably 1,000 or more, more preferably 2,000 or more, from the viewpoint of suppressing elution into the electrolytic solution. Further, Mw is preferably 50,000 or less, more preferably 10,000 or less, from the viewpoint of swellability to the solvent for electrode slurry described later. The dispersity (Mw / Mn) is preferably 1.0 to 2.0. In the present invention, Mw is a polystyrene-equivalent measured value by gel permeation chromatography (GPC) using N, N-dimethylformamide (DMF) as a solvent.

The structure of the polymer of the present invention can be estimated by quantifying the ratio (molar ratio) of carbon and nitrogen by elemental analysis. For example, when the obtained polymer is a ladder-type polymer composed of repeating units represented by the formula (1) or (2), the molar ratio of carbon to nitrogen is approximately carbon: nitrogen = 3: 1, and the formula is In the case of a highly branched polymer composed of the repeating unit represented by (3), the ratio is generally carbon: nitrogen = 5: 2. In the polymer of the present invention, the molar ratio varies depending on the content ratio of the repeating units represented by the formulas (1) to (3), and the closer to 3: 1 the closer to the ladder type polymer, the closer to 5: 2 The closer it is, the closer it is to a highly branched polymer.

In the present invention, the polymer may contain repeating units other than the repeating units represented by the formulas (1) to (3).

[Charge storage material]
The polymer of the present invention can be suitably used as a charge storage material. The charge storage material is a material capable of storing electric charge, which is useful, for example, as an electrode active material for a secondary battery.

[Secondary battery]
The secondary battery of the present invention is characterized in that a charge storage material made of the above-mentioned polymer is used as an electrode active material, and other components of the battery element may be appropriately selected from conventionally known components and used.

As an example, a general secondary battery will be described.
The secondary battery is generally composed of a positive electrode layer, a negative electrode layer, a separator layer arranged between the positive electrode layer and the negative electrode layer, and an electrolytic solution filled inside the battery element including all of them. .. The positive electrode layer and the negative electrode layer are formed on a substrate, which is a current collector, with an electrode active material, a conductive auxiliary agent made of carbon or the like to improve the conductivity of the electrode layer, if necessary, and further, if necessary. It is composed of forming a thin film containing a binder for improving uniformity, improving ionic conductivity, suppressing elution into an electrolytic solution, and the like. The electrolytic solution is composed of an electrolyte composed of a salt, which is the main body of ionic conduction, and a solvent and the like.

The charge storage material of the present invention is used as the electrode active material of the positive electrode layer or the negative electrode layer. Whether the electrode active material is used for the positive electrode layer or the negative electrode layer is not particularly limited, and is determined by the potential of the opposing electrodes. Moreover, you may use the said electrode active material for both poles.

The form of the secondary battery is not particularly limited, and any form such as a lithium ion battery, a nickel hydrogen battery, a manganese battery, and an air battery may be used. The laminating method and the production method are not particularly limited.

The electrode layer is prepared by mixing the charge storage material of the present invention, a solvent, a conductive auxiliary agent, a binder, other conventionally known electrode active materials, etc. as necessary to prepare an electrode slurry, which is used on a substrate. It can be produced by forming a thin film. The method for forming the thin film is not particularly limited, and various conventionally known methods can be used. For example, various printing methods such as offset printing, screen printing, and gravure printing using a slurry in which a material including a charge storage material is dissolved or suspended in a solvent, a dip coating method, a spin coating method, a bar coating method, and a slit (die). Examples include a coating method and an inkjet method.

Examples of the current collector used as the base of the electrode layer include metal foils such as aluminum, copper, lithium, stainless steel, iron, chromium, platinum, and gold, or substrates, and alloy foils made of any combination of these metals. Alternatively, the substrate, an oxide substrate such as indium tin oxide (ITO), indium zinc oxide (IZO), antimony tin oxide (ATO), a carbon substrate such as glassy carbon, pyrolytic graphite, carbon felt, and a carbon material can be used as described above. Examples thereof include carbon coated foil coated on metal foil.

Examples of the conductive auxiliary agent include carbon materials such as graphite, carbon black, acetylene black, vapor-grown carbon fiber (VGCF), carbon nanotubes, carbon nanohorns, and graphene, and highly conductive materials such as polyaniline, polypyrrole, polythiophene, polyacetylene, and polyacetylene. Examples include molecules. The conductive auxiliary agent can be used alone or in combination of two or more.

Examples of the binder include polytetrafluoroethylene, polyvinylidene fluoride (PVDF), polyhexafluoropropylene, vinylidene fluoride-hexafluoropropylene copolymer, polyvinyl chloride, polycarbonate, polystyrene, polyacrylic acid, and polyacrylic acid salt. Polyacrylic acid ester, polymethacrylic acid, polymethacrylate, polymethacrylic acid ester, polyester, polysulfone, polyphenylene oxide, polybutadiene, poly (N-vinylcarbazole), hydrocarbon resin, ketone resin, phenoxy resin, polyamide, ethyl cellulose, Examples thereof include vinyl acetate, ABS resin, SBR resin, polyurethane resin, melamine resin, unsaturated polyester resin, alkyd resin, epoxy resin, silicon resin, or a copolymer or blend polymer composed of any combination thereof.

Examples of the solvent for the electrode slurry include N-methyl-2-pyrrolidone (NMP), dimethyl sulfoxide, ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, γ-butyrolactone (GBL) and tetrahydrofuran (THF). Examples thereof include dioxolane, THFolan, DMF, N, N-dimethylacetamide and the like.

When the electrode active material containing the charge storage material of the present invention is used for the positive electrode layer, the negative electrode active material contained in the negative electrode layer includes graphite, carbon black, acetylene black, VGCF, carbon nanotubes, carbon nanohorns, graphene and the like. Carbon material, lithium alloy such as Li, Li-Al, Li-Si, Li-Sn, Si, SiO, SiO ₂ , Si-SiO ₂ composite, Sn, SnO, SnO ₂ , PbO, PbO ₂ , GeO, GeO ₂ , WO ₂ , MoO ₂ , Fe ₂ O ₃ , Nb ₂ O ₅ , TIO ₂ , Li ₄ Ti ₅ O ₁₂ , Li ₂ Ti ₃ O ₇ and the like.

When the electrode active material containing the charge storage material of the present invention is used for the negative electrode layer, the positive electrode active material contained in the positive electrode layer includes a compound containing a nitroxy radical group, an organic sulfur polymer, and the charge storage material of the present invention. Other than quinone polymers, quinoid materials, dione materials, organic electrode active materials such as rubianic acid materials, LiCoO ₂ , LiMn ₂ O ₄ , LiNiO ₂ , LiNi _0.5 Mn _0.5 O ₂ , Li (Ni _a Co _b Mn _c) ) O ₂ (However, 0 <a <1, 0 <b <1, 0 <c <1, a + b + c = 1), LiFePO ₄ , LiMnPO ₄ , LiCoPO ₄ , Fe ₂ (SO ₄ ) ₃ , LiMnSiO ₄ , V. _{2 Examples} include inorganic electrode active materials such as O5.

When the electrode active material containing the charge storage material of the present invention is used for the negative electrode layer, it may be used in combination with the negative electrode active material. Further, when the electrode active material containing the charge storage material of the present invention is used for the positive electrode layer, it may be used in combination with the positive electrode active material.

The electrode active material containing the charge storage material of the present invention may be used as an air electrode (positive electrode) and used as an air battery. In this case, as the negative electrode active material contained in the negative electrode layer, sodium, magnesium, aluminum, calcium, zinc or the like can be used in addition to the above-mentioned negative electrode active material.

When the positive electrode is used as an air electrode and used as an air battery, as an oxidation-reduction auxiliary material contained in the positive electrode layer, in addition to the charge storage material of the present invention, an inorganic material such as manganese oxide, 2,2,6,6- A nitroxy radical material such as tetramethylpiperidin-N-oxyl polymer may be used in combination.

The film thickness of the electrode layer is not particularly limited, but is preferably about 0.01 to 1,000 μm, and more preferably about 0.1 to 100 μm.

Examples of the material used for the separator layer include porous polyolefins, polyamides, polyesters and the like.

Examples of the electrolyte constituting the electrolytic solution include LiPF ₆ , LiBF ₄ , LiN (C ₂ F ₅ SO ₂ ) ₂ , LiAsF ₆ , LiSbF ₆ , LiAlF ₄ , LiGaF ₄ , LiInF ₄ , LiClO ₄ , and LiN (CF). ₃ SO ₂ ) ₂ , LiCF ₃ SO ₃ , LiSiF ₆ , LiN (CF ₃ SO ₂ ) (C ₄ F ₉ SO ₂ ) and other lithium salts, LiI, NaI, KI, CsI, CaI ₂ and other metal iodides, Examples thereof include iodide salts of quaternary imidazolium compounds, iodide salts and perchlorates of tetraalkylammonium compounds, and metal bromides such as LiBr, NaBr, KBr, CsBr and CaBr ₂ .

The solvent constituting the electrolytic solution does not cause corrosion or decomposition of the substance constituting the battery to deteriorate the performance, and is not particularly limited as long as it dissolves the electrolyte. For example, as a non-aqueous solvent, cyclic esters such as ethylene carbonate (EC), propylene carbonate, butylene carbonate and GBL; ethers such as THF and dimethoxyethane; dimethyl carbonate, diethyl carbonate (DEC), ethylmethyl carbonate and the like. Chain esters and the like are used. These solvents can be used alone or in admixture of two or more.

The concentration of the electrolyte in the electrolytic solution is preferably 0.001 to 2 mol / L, more preferably 0.001 to 1.2 mol / L, and from the viewpoint of obtaining a battery exhibiting higher battery performance. The concentration of the electrolyte is more preferably 0.1 mol / L or more, and further preferably 0.5 mol / L or more. By using an electrolytic solution having such a concentration, good battery performance can be exhibited. In the present invention, particularly by using the above polymer as an electrode active material, a battery capable of exhibiting good battery performance due to its electrochemical stability even in a low concentration region where the concentration of the electrolyte is less than 0.1 mol / L can be obtained. be able to.

In the present invention, a solid electrolyte may be used, and an inorganic solid electrolyte such as a sulfide-based solid electrolyte and an oxide-based solid electrolyte, or an organic solid electrolyte such as a polymer-based electrolyte can be preferably used. By using these solid electrolytes, an all-solid-state battery that does not use an electrolytic solution can be obtained.

Examples of the sulfide-based solid electrolyte include Li ₂ S-SiS ₂ -lithium compound (here, the lithium compound is at least one selected from the group consisting of Li ₃ PO _4, Li I and Li ₄ SiO ₄ ) _and Li. ₂ SP ₂ O _5, Li ₂ SB ₂ S _5, Li ₂ SP ₂ S ₅ -GeS ₂ and the like can be mentioned.
Examples of the oxide-based solid electrolyte include sodium / alumina and the like.
Examples of the polymer-based solid electrolyte include polyethylene oxide-based materials, hexafluoropropylene, tetrafluoroethylene, trifluoroethylene, ethylene, propylene, acrylonitrile, vinylidene chloride, acrylic acid, methacrylic acid, methyl acrylate, ethyl acrylate, and methyl methacrylate. , Polymer compounds obtained by polymerizing or copolymerizing monomers such as styrene and vinylidene fluoride can be mentioned. The polymer-based solid electrolyte may contain a supporting salt and a plasticizer.
In the present invention, the ionic conductivity of the solid electrolyte is preferably 10 ^-7 to 10 ^-3 S / cm, more preferably 10 ^-5 to 10 ^-3 S / cm.

Examples of the supporting salt contained in the polymer-based solid electrolyte include lithium (fluorosulfonylimide), and examples of the plasticizer include succinonitrile.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples. The equipment used and the measurement conditions are as follows.

(1) Rotation / Revolution Mixer Made by Shinky Co., Ltd., Awatori Rentaro AR-100
(2) Ball mill kneading Mini-Mill vulvisette 23 manufactured by FRISCH
(3) ¹ H-NMR spectrum, manufactured by JEOL Ltd., nuclear magnetic resonance apparatus ECX-500 (solvent: dimethyl sulfoxide-d ₆ (DMSO-d ₆ ), internal standard: tetramethylsilane)
(4) IR spectrum Fourier transform infrared spectrophotometer FT / IR-6100 manufactured by Nippon Kogaku Co., Ltd.
(5) Elemental analysis Elemental analyzer PE2400 II manufactured by PerkinElmer.
(6) Measurement of molecular weight
Equipped with RID-10A / CBM-20A / DGU-20A3 / LC-20AD / SPD-20A / CTO-20A manufactured by Shimadzu Corporation (column: TSgel SuperAW-H manufactured by Shimadzu Corporation, column temperature: 50 ° C., Solvent: DMF, detector: UV (275nm) / RI detector (built-in), calibration curve: standard polystyrene)
(7) CV measurement ALSCH1760EW manufactured by BAS Co., Ltd.
(8) Battery characteristic evaluation ALSCH1760EW manufactured by BAS Co., Ltd.

[1] Synthesis of Polymer A [Synthesis Example 1] Synthesis of 1,2,4,5-tetraamino-p-benzoquinone 1,2,4,5-tetraamino-p-benzoquinone is described in US Pat. No. 3,517,725. With reference to the method described in the book, it was synthesized as follows.
To a 100 mL flask, 1.0 g (4.07 mmol) of tetrachloro-p-benzoquinone (also known as chloranil, manufactured by Tokyo Chemical Industry Co., Ltd.) and 3.77 g (20.35 mmol) of phthalimide potassium were added, and 20 mL of dehydrated DMF was added. After that, it was reacted at 70 ° C. for 6 hours. After completion of the reaction, the precipitate was filtered off, washed in the order of warm pure water and warm ethanol, and vacuum dried to obtain 1,2,4,5-tetraphthalimide quinone as a yellow-green solid. 2 g (2.90 mmol) of the obtained 1,2,4,5-tetraphthalimide quinone was placed in a 100 mL flask, 12 mL of ultrapure water and 8 mL of hydrazine monohydrate were added, and the mixture was reacted at 70 ° C. for 1 hour. After completion of the reaction, the precipitate was filtered off, washed in the order of pure water and ethanol, and vacuum dried to give 1,2,4,5-tetraamino-p-benzoquinone as a purple solid. FIG. 1A shows the ¹ H-NMR measurement results of the obtained 1,2,4,5-tetraamino-p-benzoquinone. As a result, an amine-derived proton peak was confirmed around 4.5 ppm.

[Example 1] Synthesis of Polymer A In a 100 mL flask, 1,2,4,5-tetraamino-p-benzoquinone (500.0 mg, 2.97 mmol) obtained in Synthesis Example 1 and triquinoyl hydrate (Tokyo Kasei). (499.7 mg, 2.97 mmol) manufactured by Kogyo Co., Ltd. and 4 g of polyphosphoric acid (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) were added and reacted at 80 ° C. for 17 hours while stirring with a forced stirrer. .. The reaction solution was added dropwise to 100 mL of pure water, the precipitated solid was filtered off, the insoluble material was recovered by Soxhlet purification with methanol, and the polymer A was obtained as a black solid by vacuum drying. When the dissolved part of the obtained solid in thermal DMSO was measured by ¹ H-NMR, the proton peak derived from the amine that appeared near 4.5 ppm disappeared, so that the reaction proceeded and the polymer of the present invention was synthesized. It was confirmed that this was done (see FIG. 1 (b)). In addition, an IR measurement showed a peak derived from C = O at 1,622 cm ^-1 , suggesting that the terminal functional group is a carbonyl group. From elemental analysis, the molar ratio of carbon and nitrogen was carbon: nitrogen = 2.55: 1. The number average molecular weight Mn of the polymer A was 1,156, the weight average molecular weight Mw was 1,394, and the dispersity Mw / Mn was 1.20.

[2] Evaluation of Electrode and Battery Containing Polymer [Example 2] CV measurement of thin film electrode using polymer A Add 5 mg of polymer A, 40 mg of vapor-grown carbon fiber and 250 mg of NMP solution of 2% by mass PVDF to a ball mill for 15 minutes. The mixture was kneaded to obtain an electrode slurry. The obtained electrode slurry was applied onto a GC substrate, and this was heated and vacuum dried at 80 ° C. for 16 hours to obtain a thin film electrode (thickness: about 20 μm).
Next, the obtained electrode was immersed in the electrolytic solution, and the voids in the electrode were impregnated with the electrolytic solution. As the electrolytic solution, a GBL solution of 1 mol / L LiClO ₄ was used.
The thin film electrode is used as the working electrode 11, the platinum electrode is used as the counter electrode 12, and the Ag / AgCl electrode is used as the reference electrode 13, which are installed in a beaker, and the same electrolytic solution 14 as described above is added thereto. A beaker cell 1 as shown in 2 was produced.
Using this beaker cell 1, CV measurement was performed at a scan rate of 10 mV / sec. The results are shown in FIG. As shown in FIG. 3, the thin film electrode prepared by using the polymer A showed a redox wave at E _1/2 = 0.057V and −0.57, and was stable even after repeated sweeps.

[Example 3] Characteristic evaluation 1 (coin cell) of a battery using polymer A as an electrode
The polymer A / carbon composite electrode synthesized in Example 1 is used as a positive electrode, metallic lithium is used as a negative electrode, and the electrolytic solution is a 1 mol / L lithium hexafluorophosphate EC / DEC (= 3/7 (v / v)) solution. Selected polymer lithium secondary batteries were made. The polymer lithium secondary battery was manufactured by the following method. A polymer / carbon composite electrode was prepared on aluminum foil and cut out to a radius of 6 mm and a separator to a radius of 8.5 mm. A polymer lithium secondary battery was manufactured by laminating a plastic gasket, a carbon composite electrode, a separator, metallic lithium, a spacer, and a washer in this order on a positive terminal case, fitting a cap, and sufficiently caulking using a caulking machine holder.
The prepared battery was charged with a constant current of 4.04 μA (0.2 C) until the voltage became 4.0 V, and then discharged at 4.04 μA (0.2 C). As a result, after the voltage became almost constant for a second at around 2.0 V, it rapidly decreased, and the discharge capacity became 145 mAh / g (theoretical capacity ratio 72%). The Coulomb efficiency was about 90%. This confirmed that Polymer A was operating as an effective charge storage material. When the voltage rose to 4.0 V, charging was performed again, and charging / discharging was repeated 240 times in the range of 2.0 to 4.0 V. FIG. 4 shows the measurement result of the potential difference from the reference electrode when the charge / discharge amount is changed, and FIG. 5 shows the cycle characteristics when the charge / discharge amount is changed. Even after repeating charging / discharging 100 times, the charging / discharging capacity was maintained at 95% or more.

[Example 4] Characteristic evaluation 2 (coin cell) of a battery using polymer A as an electrode
A polymer lithium secondary battery was produced by the same procedure as in Example 3 except that the concentration of the electrolytic solution was 0.001 mol / L. The produced battery was repeatedly charged and discharged 240 times under the same conditions as in Example 3. FIG. 6 shows the measurement result of the potential difference from the reference electrode when the charge / discharge amount is changed. As a result, it was confirmed that good battery performance can be obtained even when a low-concentration electrolytic solution is used.

[Example 5] Characteristic evaluation 3 (coin cell) of a battery using polymer A as an electrode
A PEO-based solid electrolyte (ion conductivity 1.1 x 10 ^-5 S / cm) using polyethylene oxide (PEO) as the electrolyte, lithium (fluorosulfonylimide) as the supporting salt, and succinonitrile as the plasticizing agent is also used as the electrolyte. A similar polymer lithium all-solid-state battery was produced except that it was used for the separator. The prepared battery was heated at 58 ° C. or higher for 1 hour, returned to room temperature, and then a charge / discharge test was performed. The results are shown in FIG. As a result, it was confirmed that the capacity was 100 mAh / g or more at a low rate, and that good performance could be obtained even as an all-solid-state battery having low lithium ion conductivity.

1 Beaker cell 11 Working electrode (thin film electrode)
12 Counter electrode 13 Reference electrode 14 Electrolyte

Claims (14)

A polymer having an azaanthraquinone skeleton and comprising at least one selected from repeating units represented by the following formulas (1) to (3).

The polymer according to claim 1, which always contains at least one selected from the repeating units represented by the formulas (2) and (3) among the repeating units represented by the above formulas (1) to (3). A charge storage material comprising the polymer according to claim 1 or 2. An electrode active material including the charge storage material according to claim 3. An electrode slurry containing the electrode active material according to claim 4 and a solvent. A thin film containing the electrode active material according to claim 4. A thin film obtained from the electrode slurry according to claim 5. An electrode containing the electrode active material according to claim 4. An electrode comprising the thin film according to claim 6 or 7. A secondary battery comprising the electrode according to claim 8 or 9. A lithium ion battery comprising the electrode according to claim 8 or 9. The lithium ion battery according to claim 11, which contains an electrolytic solution having an electrolyte concentration of 0.001 to 2 mol / L. The secondary battery according to claim 10, which is an all-solid-state battery containing a solid electrolyte having an ionic conductivity of 10 ^-7 to 10 ^-3 S / cm. The method for producing a polymer according to claim 1, which comprises polycondensation polymerization of 1,2,4,5-tetraamino-p-benzoquinone and triquinoyl hydrate.

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