JP3020509B2 - Organic electrolyte battery - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to an organic electrolyte battery, and more particularly, to an organic electrolyte battery using a powdered insoluble and infusible substrate having semiconductor properties as a positive electrode and / or a negative electrode. About.

(Prior Art) In recent years, electronic devices have been remarkably reduced in size, thickness, and weight, and accordingly, there has been a great demand for smaller, thinner, and lighter batteries serving as power supplies. At present, silver oxide batteries are frequently used as small and high-performance batteries, and lithium batteries have been developed and put into practical use as thin light batteries and small and lightweight high-performance batteries. But these batteries are 1
Because it is a secondary battery, it cannot be used for a long time by repeating charging and discharging. On the other hand, nickel cadmium batteries have been put to practical use as high performance secondary batteries,
It is still unsatisfactory in terms of weight reduction.

Although lead-acid batteries have been used in various industrial fields as large-capacity secondary batteries, the biggest disadvantage of these batteries is that they are heavy. This is fatal because lead peroxide and lead are used as electrodes. In recent years, attempts have been made to reduce the weight and improve the performance of batteries for electric vehicles, but they have not been put to practical use. However, there is a strong demand for a large-capacity and lightweight secondary battery as a storage battery.

As described above, batteries currently in practical use each have advantages and disadvantages, and are used properly according to their applications. However, there is a great need for batteries to be smaller, thinner, or lighter. As a battery that meets such needs, recently, a battery using a thin-film polyacetylene, which is an organic semiconductor, doped with an electron-donating substance or an electron-accepting substance as an electrode active material has been studied and proposed. I have. Although this battery has high performance as a secondary battery and has the potential of being thinner and lighter, it has major drawbacks. That is, polyacetylene, which is an organic semiconductor, is a very unstable substance, is easily oxidized by oxygen in the air, and is transformed by heat. Therefore, the battery must be manufactured in an inert gas atmosphere, and there is a limitation in manufacturing polyacetylene into a shape suitable for an electrode.

Further, Japanese Patent Application No. 59-24165, which is a prior application filed by the same applicant as the applicant of the present application, discloses a heat-treated product of an aromatic condensation polymer comprising carbon, hydrogen and oxygen, The atomic ratio of atoms / carbon atoms is 0.05-0.5,
And an insoluble infusible substrate containing a polyacene-based skeletal structure having a specific surface area of at least 600 m ² / g by a BET method,
Alternatively, there has been proposed an organic electrolyte battery in which an aprotic organic solvent solution of a compound capable of generating ions capable of doping the electrode by electrolysis is used as the negative electrode and the electrolyte is used as the electrolytic solution.

The battery is a promising secondary battery in that it has high performance, has the potential of being thin and lightweight, has high oxidation stability of the electrode active material, and is easy to mold.

In this prior application, an insoluble and infusible substrate containing a polyacene-based skeleton structure is produced by heat-treating a molded product of a phenolic resin. However, in consideration of productivity, it is necessary to charge the compact in a large amount at a high filling rate in an electric furnace, and there is a problem that heat treatment under these conditions causes, for example, crater-like blisters.

(Problems to be Solved by the Invention) In view of the above problems, the present inventors have conducted intensive studies and as a result, have found that a molded product of an insoluble and infusible base powder containing a polyacene skeleton structure is used as an electrode. The present invention has been completed.

An object of the present invention is to provide a high capacity organic electrolyte battery. Another object of the present invention is to provide an economically mass-producible electrically conductive organic polymer-based powder having electrical conductivity of a semiconductor or a conductor, excellent physical properties and excellent oxidation stability. An object of the present invention is to provide an organic electrolyte battery using a material as an electrode active material. Still other objects and advantages of the present invention will be apparent from the following description.

(Means for Solving the Problems) The above-described object is to provide a powdery phenolic resin obtained by reacting a water-soluble phenolic resin precondensate and zinc chloride in an aqueous medium with stirring, and zinc chloride. Having a specific surface area value of at least 1500 m ² / g by a BET method and a hydrogen atom / carbon atom ratio of 0.5 to 0.05, which is obtained by heat-treating the composite of Example 1 in a non-oxidizing atmosphere. Wherein the powder molded body of the insoluble and infusible substrate containing is used as a positive electrode and / or a negative electrode, and an aprotic organic solvent solution of a compound capable of generating ions that can be doped into the electrode by electrolysis is used as an electrolytic solution. This is achieved by a method for producing an electrode for an organic electrolyte battery.

Examples of the phenolic resin used in the present invention include (a) a condensate of an aromatic hydrocarbon compound having a phenolic hydroxyl group and an aldehyde, such as a phenol-formaldehyde resin, and (b) a xylene-modified phenol-formaldehyde resin (a phenol-formaldehyde resin). Aromatic hydrocarbon compounds having a phenolic hydroxyl group, such as those partially substituted with xylene, are preferred.

The insoluble and infusible substrate in the present invention can be produced, for example, as follows.

First, a phenolic resin / zinc chloride composite is prepared from an aqueous solution of an initial condensate of a phenolic resin and an aqueous solution of zinc chloride.

In the conventional method, the composite was manufactured as a molded plate by a two-stage method in which the raw material was stirred and mixed while sufficiently cooling to obtain a uniform mixed solution of the raw material and then heated and cured. By forcibly stirring and mixing the above raw materials without sufficient cooling, the condensation reaction is advanced by the heat generated during the mixing, and the mixture is pulverized into fine powder by forced stirring to prepare the powdery composite. The cooling or heating temperature conditions during the stirring vary depending on the raw material composition, but are not particularly limited as long as a calorific value sufficient for the progress of the condensation reaction can be obtained. However, if the temperature is lower than 20 ° C., a problem such as easy precipitation of zinc chloride in the aqueous zinc chloride solution occurs. The particle size of the obtained composite varies depending on the production conditions, but is usually 100 μm or less.
In addition, they may be obtained as secondary aggregates of these fine particles. The mixing amount of zinc chloride is preferably 1/2 to 10/1 by weight relative to the phenolic resin. When the amount of zinc chloride is too small, the particle size of the composite becomes 100 μm or more, and when the composite is charged into an electric furnace in a large amount in a subsequent heat treatment step, only an insoluble and infusible substrate containing a heterogeneous polyacene skeleton structure can be obtained.

The concentration of the aqueous zinc chloride solution also affects the shape and size of the mixture, but the water / zinc chloride weight ratio is preferably 0.1 to 1. If the concentration is too low, zinc chloride precipitates and solidifies, making it difficult to perform uniform mixing.On the other hand, if it is too high, the particle size becomes 100 μm or more. It becomes difficult to obtain a substrate.

Further, in order to control the condensation reaction during the stirring and mixing, a commercially available product such as a substantially spherical phenolic resin such as Perpearl (manufactured by Kanebo Co., Ltd.) may be mixed into the stirring and mixing. However, if the amount of the substantially spherical phenolic resin is too large, the bulk density of the mixture tends to decrease, and the productivity tends to decrease.

The powdery phenolic resin thus obtained and the zinc chloride composite are heated in a non-oxidizing atmosphere at a temperature of 400 to 800 ° C, preferably 450 to 750 ° C, particularly preferably 500 to 700 ° C.
Heat to the temperature of By this heat treatment, the aromatic condensation polymer undergoes a dehydrogenation dehydration reaction, and a polyacene skeleton structure is formed by the condensation reaction of the aromatic ring.

This reaction is a kind of thermal condensation polymerization, and the degree of reactivity is represented by the atomic ratio represented by hydrogen atoms / carbon atoms (hereinafter referred to as H / C) in the final product. The H / C value of the insoluble infusible substrate is 0.05 to 0.6, preferably 0.15 to 0.50. When the value of H / C of the insoluble infusible substrate is larger than 0.6, the electric conductivity is not preferred because the polyacene skeleton structure is not developed. On the other hand, when the value of H / C is smaller than 0.05, the amount of dopant that can be doped becomes small.

The obtained heat-treated body is sufficiently washed with water or diluted hydrochloric acid to remove the inorganic salt contained in the heat-treated body.

Thereafter, by drying this, the insoluble infusible substrate powder of the present invention is obtained.

The insoluble infusible substrate powder of the present invention thus obtained is
The specific surface area by the BET method is at least 1500 m ² / g. When the specific surface area of the powder is less than 600 m ² / g, for example, a large amount of dopant having a large ionic radius such as ClO ₄ ⁻ , BF ₄ ⁻ , AsF ₆ ⁻ , (C ₂ H ₅ ) ₄ N ⁺ It is difficult to dope smoothly, and the performance of the battery, particularly the capacity, is reduced.

Next, the insoluble infusible substrate powder is formed into a film. By adding a conductive material and a binder to the insoluble infusible substrate powder, the film can be easily formed. The conductive agent is added to provide an appropriate electrical conductivity to the manufactured battery electrode. The electric conductivity suitable for the battery electrode is 10 ⁻⁵ S / cm or more, preferably 10 ⁻³ S / cm or more. Electric conductivity 10 ^-5
If it is less than S / cm, the internal resistance due to the electrode increases, which causes a reduction in charge / discharge efficiency, which is not preferable.

The type of the conductive agent is not particularly limited, for example, activated carbon,
Carbon-based ones such as carbon black and graphite are preferred,
The smaller the particle size, the more effective. It is also possible to use a conductive polymer as the conductive material. The proportion of the conductive material varies depending on conditions such as the electric conductivity of the insoluble and infusible base powder, the type of binder, and the molding method, but is required to be 40 to 2% by weight based on the total amount.

The type of binder is a solvent that dissolves the electrolyte used when assembling the battery, for example, organic solvents such as ethylene carbonate, propylene carbonate, γ-butyrolactone, dimethylformamide, dimethylacetamide, dimethylsulfoxide, acetonitrile, dimethoxyethane, tetrahydrofuran, dioxolan, and sulfolane. There is no particular limitation as long as it is insoluble in the solvent. For example, rubber-based binders such as SBR, fluorine-based resins such as polytetrafluoroethylene, and thermoplastic resins such as polypropylene and polyethylene are preferable, and polytetrafluoroethylene is particularly preferable. The mixing ratio varies depending on the type, but is preferably 20% by weight or less based on the total amount. If the mixing ratio exceeds 20% by weight, the electrolyte cannot sufficiently enter the inside of the electrode, and the capacity decreases, which is not preferable. .

The powder of the insoluble infusible substrate and the binder of the conductive material as described above are sufficiently kneaded and molded to form an electrode.

The organic electrolyte battery according to the method of the present invention is a powdery phenolic resin / zinc chloride obtained by condensing an aqueous solution of an initial condensate of a phenolic resin and an aqueous zinc chloride solution produced by the above-described method during stirring and mixing. Obtained by heat treating the composite in a non-oxidizing atmosphere,
The insoluble and infusible substrate powder compact containing a polyacene skeleton structure having a specific surface area value of at least 1500 m ² / g by a BET method and an atomic ratio of hydrogen atom / carbon atom of 0.5 to 0.05 is used as a positive electrode and / or Alternatively, an aprotic organic solvent solution of a compound capable of forming ions that can be doped into the electrode by electrolysis is used as an electrolyte.

Compounds used in the electrolyte that can generate ions that can be doped into the electrode include alkali metal or tetraalkylammonium halides, perchlorates, hexafluorocuprates, hexafluoroarsenates, and tetrafluorides. Borates and the like, specifically, LiI, NaI, NH ₄ I, LiClO ₄ , LiAsF ₆ , LiBF ₄ , KPF ₆ , NaPF
₄ , tetraalkyl ammonium salts such as ClO ₄ ⁻ , AsF ₆ ⁻ , PF ₆ ⁻ , and BF ₄ salts.

Examples of the aprotic organic solvent for dissolving the compound include ethylene carbonate, propylene carbonate,
γ-butyrolactone, dimethylformamide, dimethylacetamide, dimethylsulfoxide, acetonitrile, dimethoxyethane, tetrahydrofuran, methylene chloride, and mixtures thereof. Selection should be made in consideration of the solubility of the compound used as an electrolyte, battery performance, and the like. is important.

Most preferably, the concentration of the compound in the electrolytic solution is at least 0.1 mol / or more in order to reduce the internal resistance due to the electrolytic solution, and usually a range of 0.2 to 1.5 mol / is preferable.

The battery according to the method of the present invention uses a powdered insoluble and infusible substrate containing a polyacene-based skeleton structure as a positive electrode and / or a negative electrode, and an electrolyte obtained by dissolving a doping agent in an aprotic organic solvent. The battery action utilizes electrochemical doping and electrochemical undoping of a doping agent into an insoluble infusible substrate powder used as an electrode. That is, energy is stored by electrochemical doping of the insoluble infusible substrate powder with the doping agent, or is released to the outside and is extracted as electrical energy by electrochemical undoping, or internally. It is stored.

The batteries according to the present invention are divided into two types. First
The type is a battery using an insoluble and infusible substrate powder molded body for both the positive electrode and the negative electrode. The second type uses an insoluble and infusible substrate powder molded body for the positive electrode, and the negative electrode is composed of an alkali metal or an alloy thereof. This is a battery using electrodes. Specific examples of the alkali metal to be applied include, for example, cesium, rubidium, potassium, sodium, lithium and the like, and among these, lithium is most preferable.

The shape and size of the electrode formed of the powdered insoluble and infusible substrate disposed in the battery may be appropriately selected depending on the intended battery, but the battery reaction is an electrochemical reaction on the electrode surface. Therefore, it is advantageous to increase the surface area of the electrode as much as possible. As a current collector for extracting a current from the insoluble infusible substrate powder to the outside of the battery, the insoluble infusible substrate powder may be used. , Such as carbon, platinum, nickel, and stainless steel.

Next, an example of an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is an explanatory view of a battery according to the present invention. In the figure, (1) is a positive electrode (2) is a negative electrode (3) is a current collector
(4) is an electrolyte (5) is a separator (6) is a battery case (7) is an external terminal.

First, a first type of battery according to the method of the present invention, that is, a battery using an insoluble and infusible substrate powder molded body for both positive and negative electrodes will be described. The positive electrode (1) is a powdered insoluble and infusible substrate having a shape of a film or a plate, and may be doped with a doping agent or undoped. The negative electrode (2) is a molded powder of an insoluble and infusible substrate having a shape such as a film or a plate, and may be doped with a doping agent or undoped. After assembling the battery, a voltage is applied from an external power supply to dope the doping agent. For example, when using an undoped insoluble and infusible substrate powder molded body for both electrodes, the electromotive voltage of the battery after assembly of the battery is 0 V, and a voltage is applied from an external power supply to dope a doping agent to both electrodes. The battery will have an electromotive force. The current collector (3) is a device for extracting current from each electrode to the outside or supplying current for electrochemical doping, that is, charging, and a voltage drop to each electrode and the external terminal (7) by the method described above. Are connected so that no In the electrolyte solution (4), the compound capable of generating ions that can be doped into positive and negative electrodes is dissolved in an aprotic organic solvent. The electrolyte is usually in a liquid state, but may be used in a gel or solid state to prevent leakage. The separator (5) is disposed for the purpose of preventing contact between the positive and negative electrodes and holding the electrolyte, and has continuous pores that are durable to the electrode active material such as the electrolyte, the doping agent, and the alkali metal. A porous body having no conductivity is preferable, and a cloth, a nonwoven fabric, a porous body, or the like made of glass fiber, polyethylene, polypropylene, or the like is generally used. The thickness of the separator is preferably thin in order to reduce the internal resistance of the battery, but is determined in consideration of the amount of retained electrolyte, flowability, strength and the like. The positive and negative electrodes and the separator are fixed in the battery case (6) so as not to cause practical problems. The shape, size, and the like of the electrode may be appropriately determined depending on the shape and performance of the intended battery. For example, in order to manufacture a thin battery, the electrode is preferably in the form of a film. In order to manufacture a large capacity battery, it can be achieved by alternately laminating a large number of film and plate-like electrodes with both positive and negative electrodes alternately.

Next, a second type of battery according to the method of the present invention, that is, a case where an insoluble and infusible substrate powder molded body is used for the positive electrode (1) and an alkali metal or an alloy thereof is used for the negative electrode (2) will be described. . The positive electrode (1) in FIG. 1 is an insoluble and infusible substrate powder molded body, and the negative electrode (2) is an alkali metal or an alloy thereof. In the case of the second type, the doping mechanism, that is, the operation mechanism of the battery is further roughly classified into the following two.
The first is a battery provided with a mechanism in which doping of an insoluble infusible substrate with an electron-accepting doping agent corresponds to charging and undoping thereof corresponds to discharging. For example, when an undoped insoluble infusible base powder compact and an electrolyte of lithium and LiClO ₄ 1 mol / propylene carbonate solution are used as electrodes, the starting force after battery assembly is 2.5 to 3.0 V. Next, when a voltage is applied from an external power supply to dope the insoluble and infusible substrate with ClO ₄ ions, the starting force becomes 3.5 to 4.5 V. The second is a battery having a mechanism in which doping an insoluble infusible substrate powder with an electron-donating doping agent corresponds to discharging, and undoping corresponds to charging. For example, in the above-described battery configuration, the electromotive voltage after battery assembly is 2.5 to 3.0 V, and the starting force becomes 1.0 to 2.5 V when lithium ions are doped into the insoluble and infusible substrate by discharging current to the outside. When a voltage is applied from an external power supply and lithium ions are undoped, the electromotive force becomes 2.5 to 3.0 V again.

The doping or undoping may be performed under a constant current, a constant voltage, or under a condition where the current and the voltage change, but the amount of the doping agent doped into the insoluble infusible substrate powder may be The number of ions to be doped with respect to one carbon atom of the fusible substrate is preferably 0.5 to 20% in terms of percentage.

(Effect of the Invention) The organic electrolyte battery according to the method of the present invention is a battery which is used as an electrode by molding an insoluble and infusible substrate powder containing a polyacene-based skeletal structure and not generating crater-like blisters or the like.

In addition, the battery has high productivity, and an electrode is formed of an insoluble and infusible base powder containing a polyacene-based skeleton structure which can be formed into an arbitrary shape such as a film or a plate. This battery uses an electrode active material that is doped with a receptive substance, and an electrolyte that is a solution in which a compound that generates ions that can be doped into the electrode by electrolysis is dissolved in an aprotic organic solvent. It is a high-performance battery that can be reduced in weight, has a high capacity, a high output, and a long life.

 Hereinafter, the present invention will be described specifically with reference to examples.

Example 1 (1) A method for producing an insoluble and infusible substrate containing a polyacene-based skeletal structure.

Aqueous zinc chloride solution (85%)
Concentration) at a ratio of 10:30, and the mixture was heated and mixed at 70 rpm using a DMV type universal stirrer (Sanei Seisakusho) equipped with a screw beater as a stirrer while heating at 40 ° C. However, discoloration due to the curing reaction started in about 3 minutes,
After 10 minutes, a powdery phenolic resin / zinc chloride composite of 100 μm or less was obtained. 10 kg of the composite was charged into a square electric furnace, and heated at a rate of 40 ° C./hour under a nitrogen stream to perform a heat treatment to 500 ° C. Next, the heat-treated product was washed with dilute hydrochloric acid, washed with water, and then dried to obtain an insoluble and infusible base powder.

The specific surface area value of the insoluble infusible substrate powder by the BET method is 230.
0 m ² / g, and the atomic ratio of hydrogen atom / carbon atom is 0.24
Met.

(2) To 100 parts of the insoluble and infusible base powder, 10 parts of carbon black and 5 parts of polytetrafluoroethylene as a binder were added and kneaded sufficiently to obtain a plate-like molded body having a thickness of 700 μm. The molded body was punched into a disk having a diameter of 15 mm.

(3) Next to fully dehydrated propylene carbonate
LiClO ₄ was dissolved to prepare a solution of about 1.0 mol /.
This solution was used as an electrolyte, a stainless steel mesh was used as a current collector, a glass nonwoven fabric was used as a separator, and the disk-shaped molded bodies prepared in (2) above were used as a positive electrode and a negative electrode, respectively, as shown in FIG. Assembled batteries as shown.

(4) No. 1 to No. 3 batteries obtained in (3) above
The battery was charged at room temperature by applying a voltage of 2.5 V for 1 hour from an external power supply. The electromotive force after charging was 2.5V. Next, when the battery was discharged at a rate at which the undoping amount per hour was 3%, the voltage of the battery returned to 0 in one hour.

Comparative Example 1 A uniform raw material mixed solution was prepared while sufficiently cooling with a cooling ratio of 20 ° C. at the same composition ratio as in Example 1, poured into a mold of 50 × 50 × 5 mm, and heated at a temperature of 100 ° C. for 60 minutes. The curing reaction was advanced to obtain a plate-like composite molded body having a thickness of about 5 mm. The composite molded body 1
0 kg was charged into the same square electric furnace as in Example 1, and was placed in a nitrogen stream 4
Although the temperature was raised at a rate of 0 ° C./hour and the heat treatment was performed up to 500 ° C., a large amount of crater-like blisters were generated, and it was extremely difficult to remove the same.

Examples 2 to 4 (1) Insoluble and infusible base powders were obtained in the same manner as in Example 1 with the mixed compositions shown in Table 1. In each case, the basic powder was homogeneous, and no blistering occurred.

 Table 1 shows the specific surface area of the substrate.

(2) The substrate was used as an electrode in the same manner as in Example 1, and a battery was produced. Measured in the same manner as in Example 1.
Table 1 shows the discharge time up to 0V.

Example 5 (1) Production of an insoluble and infusible substrate having a polyacene skeleton structure.

A water-soluble resol (75% concentration) is mixed with a spherical phenol resin (Bellepearl manufactured by Kanebo Co., Ltd.) and an aqueous zinc chloride solution (85%
Concentration) at a ratio of 10/10/50, and stirred and mixed at 60 ° C. for 10 minutes to obtain a granular phenolic resin / zinc chloride composite. The complex was prepared in the same manner as in Example 1.
An insoluble infusible substrate powder was obtained. The substrate powder is homogeneous;
No blistering occurred. The specific surface area of the substrate powder is 22
It was 50 m ² / g.

(2) The substrate was used as an electrode in the same manner as in Example 1 to further form a battery. When the capacity was measured in the same manner as in Example 1, the voltage of the battery returned to 0 in one hour.

Example 6 The No. 2 insoluble and infusible substrate powder obtained in Example 1 (2) was molded under the same conditions as in Example 1 to form a positive electrode, a lithium metal as a negative electrode, and a glass nonwoven fabric as a separator. of
Using the solution in which LiClO ₄ was dissolved, a battery as shown in FIG. 1 was constructed.

When the battery was assembled, the open-circuit voltage was 3.0 V, and a voltage of about 4.0 V was applied to the battery from an external power supply, and the battery was discharged at a current of 2 mA until the battery voltage reached 2.0 V. Was as large as 120 wh /.

[Brief description of the drawings]

FIG. 1 shows a basic structure of a battery according to the present invention, wherein (1) is a positive electrode, (2) is a negative electrode, (3) and (3 ') are current collectors, (4) is an electrolytic solution, (5) is a separator,
(6) indicates a battery case, and (7) and (7 ') indicate external terminals.

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Taneo Okamoto 2-15-24, Kamishinjo, Higashiyodogawa-ku, Osaka-shi, Osaka Masayuki Miyake (56) References JP-A-60-170163 (JP, A) JP-A-61-80773 (JP, A) JP-A-63-218160 (JP, A) JP-A-63-301460 (JP, A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) H01M 4/02-4/04 H01M 4/60 H01M 10/40

Claims (1)

(57) [Claims] 1. A powdery phenolic resin-zinc chloride complex obtained by reacting a water-soluble phenolic resin precondensate with zinc chloride in an aqueous medium with stirring, in a non-oxidizing atmosphere. Of an insoluble infusible substrate containing a polyacene-based skeletal structure having a specific surface area value of at least 1500 m ² / g by a BET method and a hydrogen atom / carbon atom atomic ratio of 0.5 to 0.05 obtained by heat treatment at A method for producing an electrode for an organic electrolyte battery, comprising: using a powder compact as a positive electrode and / or a negative electrode; and using an aprotic organic solvent solution of a compound capable of generating ions capable of doping the electrode by electrolysis as an electrolytic solution.