JP2021157894A - Solvent-free electrode for all-solid-state secondary battery and all-solid-state secondary battery - Google Patents

Abstract

To manufacture an all-solid-state bipolar battery using the same materials for a positive electrode and a negative electrode.SOLUTION: A solvent-free electrode for an all-solid-state secondary battery includes a trioxotriangulene (TOT) derivative, a conductive auxiliary, and a solid electrolyte as an active material.SELECTED DRAWING: Figure 2

Description

The present invention relates to a secondary battery, particularly a bipolar all-solid-state secondary battery.

Lithium-ion secondary batteries (LIBs) have been put to practical use as power supplies for mobile devices and batteries for electric vehicles, but they use flammable organic solvents as the electrolyte and have a crystalline structure when overcharged as the positive electrode active material. Since metal oxide that breaks and generates heat is used, there is a problem in safety. In addition, the constituent elements of such metal oxides are rare metals, and there are problems in resource reserves and availability.

With an all-solid-state battery that does not use an electrolyte, safety issues can be solved, and a bipolar battery in which multiple positive and negative electrodes are stacked is also possible, so the voltage of a single battery cell can be increased and high output is achieved. can. However, since the current all-solid-state battery uses different materials for the positive electrode and the negative electrode, it is necessary to manufacture each separately, which increases the cost. In addition, when stacking a plurality of positive electrodes and negative electrodes, it is necessary to form positive electrodes and negative electrodes on both sides of the current collector. It is impossible to set.

On the other hand, if one type of active material that can handle both the positive electrode and the negative electrode is used, it is not necessary to separate the positive electrode and the negative electrode, and cost reduction and optimization of the manufacturing process can be easily achieved. As a candidate for such an active material, trioxotriangulene (TOT) capable of a multi-step redox reaction can be mentioned, but an all-solid-state bipolar battery has not been studied so far (Non-Patent Document 1).

Y. Morita, et al. , Nature Materials, 2011, Vol. 10, p. 947, "Organic tailored batteries materials using table open-shell molecules with degenerate frontier orbitals"

An object to be solved by the present invention is to manufacture a solvent-free electrode for an all-solid-state secondary battery and a bipolar all-solid-state secondary battery using the same material for the positive electrode and the negative electrode.

（式中、Ｘは水素原子、ハロゲン原子、アルキル基、（ヘテロ）アリール基、アラルキル基、ヒドロキシ基、アルコキシ基、アリールオキシ基、シアノ基、ニトロ基、アミノ基、チオール基、またはシリル基を表し、互いに同一でも異なっていてもよい。実線と破線からなる二重結合は非局在化した二重結合を意味しており、式中、●で表される不対電子および（−）で表される負電荷は、この非局在化二重結合中に存在する。式中、Ｍ（＋）はアルカリ金属イオンを示す。） The solvent-free electrode for an all-solid-state secondary battery of the present invention that has solved the above problems is conductively assisted by at least one of the trioxotriangulene (TOT) derivatives represented by the formulas (1) and (2) as an active material. It is characterized by containing an agent and a solid electrolyte and not containing an organic electrolyte. Hereinafter, the compound of the formula (1) may _{be represented as X 3} TOT, and the compound of the formula (2) may be represented as M ⁺ X ₃ TOT ^- or MX ₃ TOT (X and M are the formulas (1) and the formulas (1) and formulas). It has the same meaning as (2)).

(In the formula, X is a hydrogen atom, a halogen atom, an alkyl group, a (hetero) aryl group, an aralkyl group, a hydroxy group, an alkoxy group, an aryloxy group, a cyano group, a nitro group, an amino group, a thiol group, or a silyl group. Represented and may be the same or different from each other. A double bond consisting of a solid line and a broken line means a delocalized double bond, and is represented by an unpaired electron represented by ● and (-) in the equation. The represented negative charge is present in this delocalized double bond. In the equation, M (+) represents an alkali metal ion.)

It is preferable that X in the TOT derivative is a hydrogen atom.

The solid electrolyte is preferably a mixture of a polymer electrolyte and an alkali metal salt.

It is preferable that the alkali metal salt is a lithium salt and M (+) in the formula (2) is a lithium ion.

The present invention also provides a bipolar all-solid-state secondary battery having a structure in which the solvent-free electrode is used as a positive electrode and a negative electrode and a solid electrolyte is used as a separator so that both electrodes are opposed to each other.

The bipolar type all-solid-state secondary battery of the present invention is characterized in that the same active material is used for both electrodes, and since it is not necessary to separate the positive electrode and the negative electrode, great merits can be expected for simplification of the manufacturing process and cost reduction. On the other hand, the conventional bipolar battery has a difficulty in manufacturing because the positive electrode and the negative electrode are usually separate. The reason why the TOT derivative can be used as an active material for both the positive electrode and the negative electrode is that one compound can react in both directions of oxidation and reduction. Furthermore, since the alkali metal ions required for charging and discharging can be included in the structure from the beginning, there is no need to separately introduce alkali metal ions, which is a great merit.

Further, the bipolar all-solid-state secondary battery of the present invention preferably has a structure in which two or more sets of the above structures in which electrodes using a TOT derivative as an active material are combined are superposed in one battery. By combining two or more pairs of the above structures, a plurality of positive electrode-negative electrode pairs can be connected in series in one battery. Such a laminated bipolar battery can be increased in voltage according to the number of layers thereof, and can manufacture a secondary battery having a high capacity and a high output.

An electrode that does not contain a flammable organic solvent can be produced, and improvement in the safety of the secondary battery can be expected. The structure of the positive electrode and the negative electrode can be the same, which not only contributes to simplification of the manufacturing process and cost reduction, but also makes it possible to easily manufacture a laminated bipolar battery, resulting in high capacity and high output. A secondary battery can be obtained.

FIG. 1 is a cyclic voltammogram of the battery according to the first embodiment of the present invention. FIG. 2 is a graph showing the charge / discharge characteristics of the battery according to the first embodiment of the present invention. FIG. 3 is a graph showing the charge / discharge characteristics of the battery according to the second embodiment of the present invention. FIG. 4 is a graph showing the charge / discharge characteristics of the battery according to the third embodiment of the present invention. FIG. 5 is a graph showing the charge / discharge characteristics of the battery according to the fourth embodiment of the present invention. FIG. 6 is a graph showing the charge / discharge characteristics of the battery according to the fourth embodiment of the present invention. FIG. 7 is a graph showing the charge / discharge characteristics of the battery according to the fifth embodiment of the present invention.

（式中、Ｘは水素原子、ハロゲン原子、アルキル基、（ヘテロ）アリール基、アラルキル基、ヒドロキシ基、アルコキシ基、アリールオキシ基、シアノ基、ニトロ基、アミノ基、チオール基、またはシリル基を表し、互いに同一でも異なっていてもよい。実線と破線からなる二重結合は非局在化した二重結合を意味しており、式中、●で表される不対電子および（−）で表される負電荷は、この非局在化二重結合中に存在する。式中、Ｍ（＋）はアルカリ金属イオンを示す。） The solvent-free electrode for an all-solid-state secondary battery of the present invention contains at least one of the trioxotriangulene (TOT) derivatives represented by the formulas (1) and (2), a conductive auxiliary agent, and a solid electrolyte. , Does not contain organic electrolyte.

(In the formula, X is a hydrogen atom, a halogen atom, an alkyl group, a (hetero) aryl group, an aralkyl group, a hydroxy group, an alkoxy group, an aryloxy group, a cyano group, a nitro group, an amino group, a thiol group, or a silyl group. Represented and may be the same or different from each other. A double bond consisting of a solid line and a broken line means a delocalized double bond, and is represented by an unpaired electron represented by ● and (-) in the equation. The represented negative charge is present in this delocalized double bond. In the equation, M (+) represents an alkali metal ion.)

A TOT derivative in which X is a hydrogen atom, a halogen atom, or the above-exemplified group has an advantage that it is easier to synthesize than a TOT derivative in which X is a carboxyl group, and an alkali metal is added to the carboxyl group. Ion conductivity can be increased without the problem of being trapped. Further, as X, a hydrogen atom, a halogen atom, a methyl group, an ethyl group, a hydroxy group, a methoxy group, a cyano group, a nitro group, an amino group, a thiol group and the like are preferable, and a hydrogen atom is particularly preferable. When X is preferable, the theoretical charge / discharge capacity can be increased. For example, the theoretical capacity (4 electrons) of TOT in which X is a hydrogen atom is 334 mAh / g, and the theory of TOT in which X is COOLi. It can be larger than the capacity (228 mAh / g).

The TOT derivative represented by the above formula (1) is a neutral radical, and since unpaired electrons are widely delocalized in the π-electron system in the molecule, it is stable at room temperature in the atmosphere. The TOT derivative represented by the formula (2) is a monoanion, and can be obtained by reducing the TOT neutral radical of the formula (1) by one electron. Conversely, when the TOT monoanion of the formula (2) is oxidized by one electron, the TOT neutral radical of the formula (1) can be reversibly obtained. Lithium, sodium, potassium and the like can be used as M in the formula, but lithium is preferable in terms of excellent battery characteristics.

Examples of the solid electrolyte for example _{Li 2 S-P 2 S 5} , Li 3.25 Ge 0.25 P 0.75 S 4, Li 2 S-SiS 2 -Li 4 SiO 4, Li 2 S-LiI, Li 10 GeP 2 S 12, Li 7 Sulfide type such as P ₃ S ₁₁ , perovskite type such as _{La 0.51} Li _0.34 TiO _2.94 , NASICON type such as _{Li 1.3} Al _0.3 Ti _1.7 (PO ₄ ) ₃ , garnet type such as _{Li 7} La ₃ Zr ₂ O ₁₂ And polymer electrolytes can be used. A polymer electrolyte is preferable because it has a high affinity with TOT.

The solid electrolyte is preferably a mixture of a polymer electrolyte and an alkali metal salt. The polymer electrolyte is obtained as a mixture of the polymer and an alkali metal salt, and the polymer includes poly (meth) acrylic acids such as polyacrylic acid (PAA) and polymethacrylic acid (PMAA); poly2-hydroxyethylacrylate, poly. Poly (meth) acrylates such as 2-hydroxyethyl methacrylate; poly (meth) acrylamides such as polyacrylamide (PAAm), polymethacrylicamide (PMAm); polyethylene oxide (PEO), polycarbonate (PC), polyethylene terephthalate (PET), And these copolymers can be used. Of these, poly (meth) acrylic acid, poly (meth) acrylate, poly (meth) acrylamide, PEO and copolymers thereof are preferable in terms of availability and ionic conductivity, and PAA, PMAA and poly2-hydroxyethyl are preferable. Acrylate, poly2-hydroxyethyl methacrylate, PAAm, PMAm, PEO and copolymers thereof are more preferable.

As the alkali metal salt, a lithium salt, a sodium salt, a potassium salt or the like can be used, but the lithium salt is preferable because it has excellent charge / discharge characteristics of the battery. The lithium salt is not particularly limited, but LiPF ₆ , LiClO ₄ , LiBF ₄ , lithium bis (fluorosulfonyl) imide (LiFSI), and lithium bis (trifluoromethanesulfonyl) imide (LiTFSI) are preferable in terms of availability, and the battery is preferably used. LiFSI and LiTFSI are more preferable because they have excellent charge / discharge characteristics. Further, it is preferable that the metal of the alkali metal salt used and the metal of M (+) in the above formula (2) are the same.

Conductive aids include carbon blacks such as acetylene black, ketjen black, furnace black, porous carbon materials, natural graphite, carbon nanotubes (CNT), vapor-grown carbon fibers (VGCF®), graphene, graphene oxide. A reduced product or the like can be used, but acetylene black, ketjen black, porous carbon material, CNT, VGCF (registered trademark), graphene are preferable, and acetylene black and porous carbon are preferable because they are excellent in charge / discharge characteristics of the battery. Materials, CNTs and VGCF® are more preferred. The conductive auxiliary agent may be used alone or in combination of two or more. Particle-like conductive auxiliaries such as acetylene black and porous carbon materials have excellent adsorption and retention of TOT, while fibrous conductive auxiliaries such as CNT and VGCF (registered trademark) have excellent conductivity. Is preferably used in combination.

The method for producing the solvent-free electrode for an all-solid-state secondary battery according to the embodiment of the present invention is not particularly limited, and at least one of the trioxotriangulene derivatives represented by the above formulas (1) and (2). , Conductive aid, and solid electrolyte are mixed and applied or molded.

As a method of mixing, all the components may be mixed at once, or may be mixed while being added sequentially. It is preferable to add a solvent because it can be mixed efficiently. The solvent is not particularly limited, and for example, water, methanol, ethanol, propanol, isopropanol, acetone, acetonitrile, N-methylpyrrolidone (NMP), toluene, xylene, chlorobenzene, dichlorobenzene, dimethyl sulfoxide (DMSO), tetrahydrofuran (THF). , Ethyl acetate and the like can be used. Water, methanol, ethanol, acetonitrile and NMP are preferable, and water, methanol and ethanol are more preferable because each component can be efficiently dispersed and mixed.

When mixing with a solvent, a dispersion can be efficiently obtained by using various stirrers, ball mills, mixers, ultrasonic dispersers and the like. When a mixture of a polymer and an alkali metal salt is used as the polymer electrolyte, the polymer and the alkali metal salt may be mixed in advance before being mixed with other components, or both may be mixed at the same time as the other components. May be good.

The method of forming the electrode into a thin film is not particularly limited, and the electrode may be applied to a metal foil or a metal plate serving as a current collector and dried. Examples of the coating method include bar coating, spin coating, dip coating, spray coating, screen printing, gravure printing, and inkjet printing. After application, it is dried by heating or reducing the pressure as appropriate. It is also possible to increase the density of the electrodes by pressing during or after drying. When mixed without using a solvent, the obtained mixture may be directly pressed into a sheet to form an electrode. The type of metal foil or metal plate used as the current collector is not particularly limited, and aluminum, copper, stainless steel, iron, or the like can be used, and any shape such as foil, sheet, or mesh can be used.

The film thickness of the electrode according to the embodiment of the present invention is not particularly limited, but if it is thin, the battery capacity becomes small, and if it is thick, the drying process takes time and the high-speed charge / discharge characteristics deteriorate. In terms of the balance between the two, the range of 5 μm to 300 μm is preferable, and the range of 20 μm to 150 μm is more preferable.

The content of each component in the electrode according to the embodiment of the present invention is not particularly limited, but the TOT derivative is a TOT derivative, a conductive auxiliary agent, and a solid electrolyte in a total of 100% by mass in that the charge / discharge characteristics of the battery are excellent. It is preferably contained in an amount of 20 to 95% by weight, more preferably 30 to 90% by weight, and even more preferably 30 to 80% by weight. The more the TOT derivative is contained, the larger the charge / discharge capacity of the battery is, but if it is too large, the transfer efficiency of electrons and ions is lowered, and the high-speed charge / discharge characteristics are deteriorated.

The conductive auxiliary agent is preferably contained in an amount of 1 to 20% by weight based on 100% by mass of the total of the TOT derivative, the conductive auxiliary agent and the solid electrolyte in order to balance the securing of electronic conductivity and the maximization of the battery capacity. , 2 to 15% by weight, more preferably. The ratio of the particulate conductive auxiliary agent to the fibrous conductive auxiliary agent (particle conductive auxiliary agent: fibrous conductive auxiliary agent) when the particulate conductive auxiliary agent and the fibrous conductive auxiliary agent are combined is not particularly limited, but is a weight ratio. The range of 95: 5 to 40:60 is preferable, the range of 90: 10 to 45:55 is more preferable, the range of 80:20 to 50:50 is more preferable, and the range of 75:25 to 55:45 is preferable. You may. By combining the particulate conductive auxiliary agent and the fibrous conductive auxiliary agent in the above range, it is possible to obtain a conductive auxiliary agent having excellent adsorption and retention of TOT and excellent electrical conductivity.

In order to balance the securing of ionic conductivity and the maximization of battery capacity, the solid electrolyte is preferably contained in an amount of 3 to 70% by weight based on 100% by mass of the total of the TOT derivative, the conductive auxiliary agent and the solid electrolyte. It is preferably contained in an amount of 10 to 60% by weight, more preferably 15 to 55% by weight. When a mixture of a polymer and an alkali metal salt is used as the solid electrolyte, the content ratio (polymer: alkali metal salt) of the two is not particularly limited, but the weight ratio is in the range of 50:50 to 95: 5 in terms of excellent ionic conductivity. Is preferable, the range of 60:40 to 90:10 is more preferable, and the range of 65:35 to 80:20 is even more preferable.

When producing the electrode according to the embodiment of the present invention, a binder may be used in combination for the purpose of enhancing the adhesiveness between the current collector and each component. As the binder, for example, polyvinylidene fluoride, polytetrafluoroethylene, polyimide, styrene-butadiene rubber, polyacrylonitrile, PAA and the like can be used.

It is also a preferable aspect that the electrode according to the embodiment of the present invention does not contain a binder. Since the above conductive auxiliary agent is used, the electrode can be manufactured without containing a binder. Since the binder does not participate in charging / discharging, it is preferably as small as possible, and more preferably not contained, from the viewpoint of increasing the charging / discharging capacity of the battery.

A bipolar solid secondary battery having a structure in which the electrodes according to the embodiment of the present invention are the positive electrode and the negative electrode and the solid electrolyte is used as the separator and the two electrodes are opposed to each other can be obtained. According to the present invention, a bipolar battery can be obtained by making the same electrodes face each other via a solid electrolyte separator. In this case, one becomes a positive electrode and the other becomes a negative electrode depending on how the charging / discharging potential is applied.

It is also possible to form a bipolar solid secondary battery having a structure in which two or more sets of the above structures are superposed in one battery, and to superimpose a plurality of layers of the bipolar structure in one battery. Since this corresponds to connecting batteries in series, the voltage can be increased as the number of layers to be stacked increases.

Hereinafter, the present invention will be described with reference to Examples. The present invention is not limited by the following examples, and it is of course possible to carry out the present invention with appropriate modifications within a range that can be adapted to the above-mentioned purpose, and all of them are technical of the present invention. Included in the range.

Percentages and parts representing the content or amount used are based on weight unless otherwise specified. The TOT neutral radical derivative (H ₃ TOT) and the TOT mono anion derivative (LiH ₃ TOT) were synthesized by the method described in Non-Patent Document 1 using 2-iodotoluene as a starting material. Acetylene black (AB) is Denka black made by Denka, gas phase growth carbon fiber (VGCF (registered trademark)) is made by Showa Denko, polyvinylidene fluoride (PVDF) is KF polymer made by Kureha, and poly (ethylene oxide) (PEO) is Osaka soda. Was used. The electrode film thickness was measured using a gauge MT1281 manufactured by Heidenhain Co., Ltd. The charge / discharge test was carried out using a CR2032 coin cell with a charge / discharge tester BCS-810 manufactured by Biologic.
(Example 1)
<Preparation of electrodes>
Li ⁺ H ₃ TOT as an active material ^- (100 mg), a conductive auxiliary agent as AB (16 mg) and VGCF (registered trademark) (4 mg), lithium bis as a polymer electrolyte (trifluoromethanesulfonyl) imide (LiTFSI) (24 mg) and PEO (56 mg), acetonitrile (1.7 g) were mixed with a planetary stirrer deaerator as a dispersion ^{_{solvent, Li + H 3 TOT - /}} AB / VGCF ( TM) / LiTFSI / PEO (50: 8: 2: 12 : 28) (weight ratio) slurry was obtained. An appropriate amount of this slurry was spin-coated on a stainless steel disk having a diameter of 15 mm and dried to prepare a solvent-free electrode for an all-solid-state secondary battery.

<Battery production and evaluation>
The two electrodes were opposed to each other via a LiTFSI-containing PEO film (φ16 mm) manufactured by Osaka Soda Co., Ltd. as a separator, and were placed in a CR2032 coin cell together with a spring and crimped to prepare a battery. In the initial state, the voltage is 0 V because there is no difference in electrochemical potential between the two poles. The result of cyclic voltammetry of this battery from 0V → 2.6V → 0V is shown in FIG. A reversible redox wave was observed. Next, this battery was charged and discharged at 80 ° C. for 10 cycles at a voltage range of 2.1-0 V and a rate of 0.1 C. The charge / discharge curve is shown in FIG. Although it has a large irreversible capacity with respect to the initial charge, it operates stably as a secondary battery and maintains a discharge capacity of 10 mAh / g or more.

(Example 2)
<Preparation of electrodes>
Li ⁺ H ₃ TOT as an active material ^- (100 mg), a conductive auxiliary agent as AB (16 mg) and VGCF (registered trademark) (4 mg), LiTFSI as a polymer electrolyte (22 mg) and PEO (57 mg), acetonitrile (1 a dispersion solvent .5 g) was mixed with a planetary stirring and defoaming device to prepare a slurry of Li ⁺ H ₃ TOT ⁻ / AB / VGCF® / LiTFSI / PEO (50: 8: 2: 11: 29) (weight ratio). Obtained. An appropriate amount of this slurry was spin-coated on a stainless steel disk having a diameter of 15 mm and dried to prepare a solvent-free electrode for an all-solid-state secondary battery.

<Battery production and evaluation>
The two electrodes were opposed to each other via a LiTFSI-containing PEO film (φ16 mm) manufactured by Osaka Soda Co., Ltd. as a separator, and were placed in a CR2032 coin cell together with a spring and crimped to prepare a battery. The battery was charged and discharged at 60 ° C. for 8 cycles at a voltage range of 1.8-0.2 V and a rate of 0.01 C. The charge / discharge curve is shown in FIG. Although the capacity decreased with each cycle, it operated stably as a secondary battery.

(Example 3)
<Preparation of electrodes>
Example 2 prepared _{^{Li + H 3 TOT - / AB}} / VGCF ( TM) / LiTFSI / PEO (50: 8: 2: 11: 29) spins the slurry appropriate amount (by weight) on a stainless steel disk having a φ15mm It was coated and dried to prepare a solvent-free electrode for an all-solid-state secondary battery.

<Battery production and evaluation>
The two electrodes were opposed to each other via a LiTFSI-containing PEO film (φ16 mm) manufactured by Osaka Soda Co., Ltd. as a separator, and were placed in a CR2032 coin cell together with a spring and crimped to prepare a battery. This battery was charged and discharged at 60 ° C. for 9 cycles at a voltage range of 1.8-0.2 V and a rate of 0.01 C. The charge / discharge curve is shown in FIG. Although the capacity decreased with each cycle, it operated stably as a secondary battery.

(Example 4)
<Preparation of electrodes>
Li ⁺ H ₃ TOT as an active material ^- (40 mg), a conductive auxiliary agent as AB (8 mg) and VGCF (registered trademark) (2 mg), LiTFSI as a polymer electrolyte (14 mg) and PEO (36 mg), ethanol (1 a dispersion solvent were mixed .8G) with a planetary stirrer _{^{deaerator, Li + H 3 TOT - /}} AB / VGCF ( TM) / LiTFSI / PEO (40: 8: 2: 14: 36) a slurry of (by weight) Obtained. Ethanol was slightly evaporated from this slurry and concentrated, and then an appropriate amount was spin-coated on a stainless steel disk having a diameter of 15 mm and dried to prepare a solvent-free electrode for an all-solid-state secondary battery.

<Battery production and evaluation>
The two electrodes were opposed to each other via a LiTFSI-containing PEO film (φ16 mm) manufactured by Osaka Soda Co., Ltd. as a separator, and were placed in a CR2032 coin cell together with a spring and crimped to prepare a battery. The battery was charged and discharged at 80 ° C. for 5 cycles at a voltage range of 1.8-0.1 V and a rate of 0.1 C. The charge / discharge curve is shown in FIG. It operated stably as a secondary battery, and there was almost no decrease in capacity with each cycle. Further, FIG. 6 shows the results of charging and discharging this battery under the same conditions except that the voltage range was changed to 1.5-0.1 V. Even if the charging voltage was reduced, the battery was charged and discharged without any problem.

(Example 5)
<Preparation of electrodes>
_{H 3} TOT (40 mg) as active material, AB (8 mg) and VGCF® (2 mg) as conductive aid, LiTFSI (14 mg) and PEO (36 mg) as polymer electrolyte, methanol (3.0 g) as dispersion solvent Was mixed and irradiated with ultrasonic waves _{to obtain a dispersion of H 3} TOT / AB / VGCF (registered trademark) / LiTFSI / PEO (40: 8: 2: 14: 36) (weight ratio). This dispersion was spray-coated on an aluminum sheet heated to 200 ° C. on a hot plate and then dried to prepare a solvent-free electrode for an all-solid-state secondary battery. This electrode was punched into a circle having a diameter of 15 mm to obtain a positive electrode. Similarly Li ⁺ H ₃ TOT instead of H ₃ TOT ^- was used to produce a negative electrode.

<Battery production and evaluation>
The positive electrode and the negative electrode were made to face each other as a separator via a LiTFSI-containing PEO film (φ16 mm) manufactured by Osaka Soda Co., Ltd., and were placed in a CR2032 coin cell together with a spring and crimped to prepare a battery. This battery was charged and discharged at a voltage range of 1.0-0 V, a rate of 0.1 C, and 60 ° C. The charge / discharge curve is shown in FIG. Although the discharge capacity is as small as 20 mAh / g with respect to the charge capacity of 100 mAh / g, it was confirmed that the battery operates as a bipolar battery using the same TOT for both poles.

(Comparative Example 1)
<Preparation of electrodes>
_{LiCoO 2} (85.5 mg) as an active material, AB (9.5 mg) as a conductive auxiliary agent, PVDF (5 mg) as a binder, and NMP (1.6 g) as a dispersion medium are mixed and kneaded with a planetary stirring defoaming device. By doing so, _{a slurry of LiCoO 2} / AB / PVDF (85.5: 9.5: 5) (weight ratio) was prepared. This slurry is applied to an aluminum foil (thickness 20 μm) using a bar coater with a gap of 300 μm, dried at 120 ° C. for 1 hour, and then pressed with a roll press machine at ^{a pressure of 800 kg / cm 2} to a thickness of 56.6 μm (thickness 56.6 μm). An electrode sheet (including aluminum foil) was obtained. This sheet was punched into a circle having a diameter of 15 mm to form an electrode. The electrodes were impregnated with 56.1 μL of an acetonitrile solution containing LiTFSI (2 mg / mL) and PEO (5 mg / mL) and dried.

<Battery production and evaluation>
The two electrodes were opposed to each other via a LiTFSI-containing PEO film (φ16 mm) manufactured by Osaka Soda Co., Ltd. as a separator, and were placed in a CR2032 coin cell together with a spring and crimped to prepare a battery. In order to charge and discharge this battery, I tried to charge it to 1.5V at 0.1C and 80 ° C., but no current flowed and the voltage remained 0V, so charging and discharging was not possible. This is because LiCoO _{2 on the} negative electrode side cannot insert lithium ions any more, and generally, the same metal oxide-based active material cannot be used for the positive electrode and the negative electrode at the same time.

Claims (6)

An all-solid secondary battery containing at least one of the trioxotriangulene (TOT) derivatives represented by the formulas (1) and (2) as an active material, a conductive auxiliary agent, and a solid electrolyte, and not containing an organic electrolyte. Solvent-free electrode for batteries.

(In the formula, X is a hydrogen atom, a halogen atom, an alkyl group, a (hetero) aryl group, an aralkyl group, a hydroxy group, an alkoxy group, an aryloxy group, a cyano group, a nitro group, an amino group, a thiol group, or a silyl group. Represented and may be the same or different from each other. A double bond consisting of a solid line and a broken line means a delocalized double bond, and is represented by an unpaired electron represented by ● and (-) in the equation. The represented negative charge is present in this delocalized double bond. In the equation, M (+) represents an alkali metal ion.) The solvent-free electrode for an all-solid-state secondary battery according to claim 1, wherein X of the TOT derivative is a hydrogen atom. The solvent-free electrode for an all-solid-state secondary battery according to claim 1 or 2, wherein the solid electrolyte is a mixture of a polymer electrolyte and an alkali metal salt. The solvent-free electrode for an all-solid secondary battery according to claim 3, wherein the alkali metal salt is a lithium salt and M (+) in the formula (2) is a lithium ion. A bipolar all-solid-state secondary battery having a structure in which the electrodes according to any one of claims 1 to 4 are a positive electrode and a negative electrode, and a solid electrolyte is used as a separator and the two electrodes are opposed to each other. A bipolar all-solid-state secondary battery having a structure in which two or more sets of the structures according to claim 5 are superposed in one battery.

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