JP2536865B2 - Battery active material - Google Patents

Description

TECHNICAL FIELD The present invention relates to a novel polymer active material for a battery.

2. Description of the Related Art In recent years, various organic secondary batteries using a polymer material having a conjugated double bond as an active material have been proposed. For example J.
Chem.Soc.Chem.Commun., 317 (1981); J. Electrochem.So
C., 128, 1651 (1981) and the like use a battery using polyacetylene, and J. Chem. Soc. Chem. Commun., 361 (1982) use a battery using polyphenylene, JP-A-61-216470. There is a battery using polypyrrole in France Patent No. 255358.
No. 1 proposes a battery using polyaniline.

OBJECT The object of the present invention is to provide a novel polymer active material for a battery, which can be used as a battery active material, like conventional polymer materials such as polyacetylene and polyphenylene.

Structure The active material for a battery of the present invention comprises a polymer of 1,2-di (2-thienyl) ethene and its derivative.

We have the general formula I (N is a natural number, R is H or an alkyl group having 1 to 3 carbon atoms) has a resonance structure, and two α-positions are present in the thiophene skeleton, which facilitates electrochemical polymerization. Possibility, further, like polythiophene and polyacetylene, since the polymer of the compound of the general formula I is a possibility as an active material for a battery as a conjugated polymer, various compounds of the general formula I are polymerized, The properties of the active material were investigated. As a result, n in the general formula I is 1, 1,
2-di (2-thienyl) ethene and 1- (4-methyl-2-thienyl) -2-wherein n is 1 and R is a methyl group.
The inventors have found that a polymer of (2-thienyl) ethene is an excellent active material for batteries and have reached the present invention.

The polymer of the present invention can be easily produced by the electrochemical method as described above. This electrochemical method is generally described, for example, in J. Electrochem. Soc. Vol. 130, No 7.1506-1509 (19
83); Electrochimica Acta Vol.27, No1, 61-65 (198
2); J. Chem. Soc., Chem. Commun. 1199 (1984) and the like. In the present invention, a solution of a monomer and an electrolyte dissolved in a solvent is anodized in an electrolytic cell. The electrolytic polymerization reaction is carried out. In this case, as the electrolyte, LiPF ₆ , LiSbF ₄ , LiAsF ₆ , LiClO ₄ , NaClO ₄ ; KI, KPF ₆ , KS
_{bF 4, KAsF 6, KClO 4} , AgBF 4, NaBF 4, NaAsF 6, NaPF 6, [(n-C
₄ H ₉ ) ₄ N] ⁺ · (AsF ₆ ) ^- , [(n-C ₄ H ₉ ) N] ⁺ · Cl
O ₄ ^-, LiAlCl _4, or _{FeCl 3, AlCl 3, ZnCl 2} , AlBr 3, BF Friedel-Crafts reaction catalyst such as ₃ can be used. As the solvent, acetonitrile, benzonitrile, propylene carbonate, γ-butyrolactone, dichloromethane, dioxane, dimethylformamide, or a nitro solvent such as nitromethane, nitroethane, nitropropane or nitrobenzene can be used. Examples of the material forming the electrodes for anodic oxidation include metals such as Au, Pt, and Ni, Sn.
Metal oxides such as O ₂ and In ₂ O ₃ or their composites or coatings can be used.

As the electrolysis method, any of constant voltage electrolysis, constant current electrolysis and constant potential electrolysis is possible, but constant voltage electrolysis and constant current electrolysis are suitable, and constant current electrolysis is particularly preferable from the viewpoint of mass production.
Further, the adjustment of the current density is important because it has a great influence on the morphology of the film, and it is necessary to change it slightly depending on the combination of the components of the electrolyte solution. In the case of the polymer material of the present invention, this current density is preferably in the range of 1.0 to 2.0 mA / cm ² .

The method for producing the polymer material of the present invention can be electrochemically polymerized as described above, but the production method is not particularly limited.

In any case, the degree of polymerization of the thus obtained polymer of 1,2-di (2-thienyl) ethene and its derivative is preferably 10 or more.

The polymer material of the present invention obtained as described above is used as an active material for batteries. When the active material of the present invention is used for a positive electrode, it is used as a negative electrode active material for this positive electrode active material. Examples of the organic polymer material include metals such as Li, Zn, Cu and Ag, and organic polymers such as acetylene, benzene, thiophene and diphenylbenzidine. In any case, the voltage of the battery is expressed as the potential difference between the positive electrode and the negative electrode, and therefore, it is necessary to select and combine active materials for the positive electrode and the negative electrode having appropriate electric potentials.

The polymer positive electrode active material for a battery as described above is doped with anions constituting an electrolyte in an electrolytic solution to store energy, and is dedoped to release energy through an external circuit. PF ₆ Such anionic dopant ^{_{-, SbF 4 -, AsF 6}} -, SbCl 6 - halides Va group elements such as anion; BF ₄ ^- halide anions of III a group element such as; ClO ₄ ^- Perchlorate anion and the like. Specific examples of the compound (electrolyte in the battery electrolyte) that provides these dopants include LiPF ₆ , LiSbF ₄ , L
iAsF ₆ , LiClO ₄ , NaClO ₄ , KI, KPF ₆ , KSbF ₄ , KAsF ₆ , KClO ₄ ,
_{[(N-C 4 H 9)} 4 N ] ⁺ · AsF ₆ ^-, _{[(n-C 4 H 9)} 4 N ] ⁺ ·
ClO ₄ ^-, there is a LiAlCl _4, LiBF ₄ or the like.

Further, as the solvent of the electrolytic solution of the battery, it is preferable to use a polar aprotic solvent which is aprotic and has a large dielectric constant. Specifically, for example, ketones, nitriles,
Examples thereof include esters, ethers, carbonates, nitro compounds, sulfolane compounds, and mixtures thereof. Among these, nitriles, carbonates, sulfolane compounds are preferable. Typical examples thereof include acetonitrile, propionitrile, butyronitrile, valeronitrile, benzonitrile, ethylene carbonate, propylene carbonate, γ-butyrolactone, sulfolane and 3-methylsulfolane.

 The present invention will be described below with reference to examples.

Example 1,2-di (2-thienyl) ethene 20 mg and tetrabutylammonium tetrafluoroborate Tetrabutylammonium 660 mg in an electrolytic solution dissolved in acetonitrile 20 ml, Nesa glass (30 Ω / cm ² ) as an anode, Ni plate as a cathode, A 1,2-di (2-thienyl) ethene polymer was produced on Nesa glass by conducting a constant voltage electrolysis of 3.5V.

Next, as shown in FIG. 1, the Nesa glass to which the polymer is attached is used as the positive electrode 1 (2 is the Nesa glass, 3 is the polymer), and Li is used as the negative electrode 4 in the electrolyte solution 5 consisting of 1M-LiBF ₄ propylene carbonate solution. The charge / discharge characteristics of the 1,2-di (2-thienyl) ethene polymer were measured with a charge / discharge measuring device 6. The results are shown in FIG. The open-circuit voltage, Coulomb efficiency and energy efficiency were measured by the following methods, and 3.
Results of 8V, 80% and 74% were obtained.

Open circuit voltage: Measured after charging the voltage between both electrode terminals and leaving it for 10 minutes.

Coulombic efficiency and energy efficiency: Measured by charging and discharging with constant current (0.1mA / cm ² ).

In addition, the number of repetitions of charging and discharging of the battery having this configuration was several tens or more.

Effect As described above, the 1,2-di (2-thienyl) ethene-based polymer of the present invention has performance as an active material for batteries, as can be seen from the charge / discharge characteristic curve of FIG.

[Brief description of drawings]

FIG. 1 is an apparatus diagram for measuring charge / discharge characteristics of the batteries prepared in Examples, and FIG. 2 is a charge / discharge characteristic curve diagram of the 1,2-di (2-thienyl) ethene polymer of the present invention. . 1 ... Positive electrode in which the polymer 3 of the present invention is attached to Nesa glass 2 ... Li negative electrode, 5 ... Electrolyte 6 ... Charge / discharge measuring device

Claims (1)

(57) [Claims] 1. A battery active material comprising a 1,2-di (2-thienyl) ethene polymer.