JPH0612667B2 - New battery - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A battery using lithium as a negative electrode active material and iodine as a positive electrode active material is used as a backup power source for cardiac pacemakers and computers (J. Power Sour).
ces, 5 , 15 (1980) etc.). In most cases, this battery is manufactured without using a solvent, and because the battery functions in the absence of solvent, this battery can withstand long-term storage and use without the risk of liquid leakage, It is used as a backup power source for pacemakers and computers. That is, in this battery, Li produced by the reaction of lithium and iodine (or battery reaction)
I intervenes between the positive electrode and the negative electrode, and this solid electrolyte functions to make the battery function normally even in the absence of solvent (that is, in the absence of electrolyte solution). Li as a solid electrolyte
In addition to I, Al ₂ O ₃ or the like may be used. Thus, a battery that uses lithium as a negative electrode active material and iodine as a positive electrode active material and does not use a solvent has a great practical advantage. However, in the production of this battery, the positive electrode active material iodine is a polymer compound. It is necessary to use it as a composition obtained by mixing (or forming an adduct) with the above. That is, since iodine is a poor conductor of electricity with an electric conductivity of 10 ^-6 S · cm ^-1 or less at room temperature, and is poor in moldability,
In order to use it as an electrode material for batteries, it is necessary to increase the electrical conductivity and moldability by preparing a polymer compound and the above composition. Several examples of such polymer compounds that make up a composition with iodine have been reported, such as poly (2-vinylpyridine) and nylon-6 (J. Power Sources, 5 , 15 (1980); Inorg.Chim.Act
a, 77 , L179 (1983), etc.) are polymer compounds that do not have a π-conjugated system along the main chain and
There is no report that a composition comprising a polymer compound having a conjugated system and iodine is used as a positive electrode mixture of the above lithium solid electrolyte battery.

In the present invention, a polymer having a π-conjugated system along the main chain makes a composition electrically conductive with iodine (J. Chem. Phys., 73 , 94).
6 (1980); J. Chem. Phys., 71 , 1506 (1979); Bull. Chem. So
c. Jpn., 56 , 1503 (1983)), and using this composition as a positive electrode mixture of the above lithium solid electrolyte battery, it has the following advantages.

That is, in order for the composition of iodine and the polymer compound to effectively function as the positive electrode mixture, the electric conductivity of the composition should be about 10 ⁻⁵ S · cm ⁻¹ or more. Desirably, at this time, the internal resistance of the battery due to the positive electrode mixture can be suppressed and the battery can function effectively. In the existing lithium solid electrolyte battery using a composition composed of a polymer having no π-conjugated system along the main chain and iodine as a positive electrode mixture, the electrical conductivity of this composition is higher than that of iodine in the composition due to discharge. The electrical conductivity decreases when the weight of iodine, which is not involved in discharge, becomes smaller than that of the polymer compound and the weight ratio of iodine in the composition composed of iodine and polymer compound is less than about 50%. Degrees are usually below 10 ^-5 S · cm ^-1 . Therefore, in a lithium solid state battery using a composition of a polymer compound having no π-conjugated system along the main chain and iodine as a positive electrode mixture, a battery reaction (positive electrode: composition + e ⁻ → I ⁻ + polymer compound is effectively performed. The proportion of iodine in the composition used for the negative electrode: Li → Li ⁺ + e ⁻ ) can be suppressed to a certain low level due to the increase in the resistance of the positive electrode mixture due to discharge and the increase in the internal resistance of the battery accompanying it. . When the lithium solid electrolyte battery is used in a pacemaker of the heart or the like, the internal resistance of the battery is preferably on the order of 10 ⁵ Ω or less. In the battery of the present invention, iodine can be effectively used in the battery using the composition of the polymer compound having no π-conjugated system along the main chain and iodine. That is, poly (2,
5-thienylene) or a derivative thereof such as poly (3-alkyl-2,5-thienylene), and a π-conjugated system selected from a derivative thereof such as poly (pyrrolylene) or poly (N-substituted 2,5-pyrrolylene) In the composition of the polymer compound and iodine of the present invention having the above, one having an electric conductivity of 10 ⁻⁵ S · cm ⁻¹ or more is usually used even when the weight ratio of iodine to the polymer compound is as low as about 10%. In many cases, if self-discharge is not taken into consideration, a battery capable of highly discharging iodine by utilizing iodine can be produced using this composition. For example, when the content of iodine is 15% by weight based on the polymer, the electric conductivity of the composition is 10 ⁻⁵ Scm ⁻¹ or more.
As a result, even if a battery of the same weight is manufactured, a battery that can be used for a longer period of time can be obtained. This means that, for example, when considering a battery for a cardiac pacemaker, the battery implanted in the patient's body is replaced by surgery. It will lead to the extension of the period necessary for, and the practical advantage will be great.

In the composition used in the present invention, an electron is transferred from the polymer compound to iodine and a positive charge is present in the polymer compound, and iodine is I ⁻ or polyiodide ion I _m ^−.
May exist as (Bull.Chem.Soc.Jpn., 56 ,
1503 (1983)). In this case, the battery functions by the positive charge in the polymer compound flowing to the negative electrode side during the discharge reaction, and the electromotive force of the battery is slightly different from the value calculated from the standard energy of lithium, iodine and LiI. It becomes a value. However, even in this case, the electric charge of the composition as a whole is substantially zero, and the change in the electromotive force of the battery is practically not a problem.

Examples of the polymer compound of the present invention which forms a composition with iodine include poly (2,5-thienylene) or a derivative thereof such as poly (3-alkyl-2,5-thienylene), and poly (pyrrolylene) or poly (N). -Substituted-2,5-pyrrolylene) and its derivatives such as π along these backbones are suitable.
An adduct or composition of a polymer compound having a bond and iodine has semiconductivity. The main component of the positive electrode mixture is the above composition, but carbon powder may be mixed into the positive electrode mixture as needed. In addition, the negative electrode active material is changed from lithium to magnesium,
Even if the metal is changed to another metal such as zinc, the corresponding batteries can be manufactured.

Example 1. In the composition of iodine and poly (2,5-thienylene), the weight ratio of iodine to poly (2,5-thienylene) is 15%, 100%.
%, 150%, 400% at room temperature 2 × 10 ^-4 S ・ cm ^-1 , 1
Electrical conductivity of × 10 ^-2 S · cm ⁻¹ , 4 × 10 ⁻² S · cm ⁻¹ , 8 × 10 ⁻³ S · cm ⁻¹ was shown. Iodine and poly (2,5-thienylene) are placed in a glass tube at a weight ratio of 3: 1, air in the glass tube is removed by a vacuum pump, and then the glass tube is sealed. After heating this glass tube in an oil bath at 150 ° C. for 15 hours, it is taken out from the oil bath and opened. When the glass tube was taken out of the oil bath and returned to room temperature, free iodine was substantially absent, and the composition was formed by adding iodine and poly (2,5-thienylene) in a weight ratio of 3: 1. The thing was obtained. 61.2 mg of this product (composition) and a 0.5 mm-thick lithium plate (manufactured by Mitsui Mining & Smelting Co., Ltd.) were placed in a stainless steel container (Inorg.Chim.Acta, 77 , L179 (Dia. 11 mm in diameter and 2 mm in thickness). 1983)) and sealed in an argon stream to fabricate a button-type battery. The positive electrode and the negative electrode of this button-type battery are insulated by polypropylene, and LiI generated between both electrodes by the reaction of the above-mentioned composition as the positive electrode active material and Li as the negative electrode active material plays the role of a solid electrolyte. The operation in an argon stream was performed in a Takabayashi Rika Co., Ltd. glow box.
When the button-type battery obtained in this way was discharged under a resistance of 500 kΩ, the closed circuit voltage at the start of discharge was
It was 2.8V, and the closed circuit voltage became 2.3V after about 1630 hours. During this period, the average closed circuit voltage was 2.58V. That is, during the above discharge period, the average is 2.58 ÷ (5 × 10 ⁵ ) =
This means that a current of 5.16 × 10 ^-6 A was flowing, and if the discharge end voltage is 2.3 V, 5.16 × 10 ^-6 × 1630 × 3600 = 30.
3 The amount of electricity in Coulomb has been discharged. On the other hand, the weight of iodine in the composition used in this example was 61.2 ×
0.75 = 45.9 mg, which is 45.9 × 10 ^-3 × 96500 ÷ 127 =
Equivalent to 34.9 Coulomb electricity. Therefore, in this example, it is shown that 30.3 / 34.9 = 87% of iodine was effectively used for discharging. This iodine utilization rate is approximately the same as that of a button-type battery (Inorg.Chim.Acta, 77) that uses lithium obtained as a negative electrode active material and a composition of nylon-6 and iodine as a positive electrode active material using the same device. , L179 (1983)), the utilization rate (40 to 50%) of iodine obtained during discharge under a resistance of 500 kΩ is exceeded. In this way, it was found that the composition composed of poly (2,5-thienylene) having a continuous π-conjugated system along the main chain and iodine became the positive electrode active material of the lithium-iodine solid electrolyte battery. The poly (2,5-thienylene) used in this example was obtained by using a reaction mixture of 2,5-dibromothiophene and magnesium in a molar ratio of 1: 1 in the presence of a nickel complex catalyst as a raw material. After removing low molecular weight compounds by chloroform extraction (Bull.Chem.Soc.Jpn., 56 , 1497
(1983)). Molecular weight is about 2600 (patent 1200926)
Is believed to be.

Example 2. Example 1. A composition containing poly (2,5-thienylene) and iodine in a weight ratio of 1: 1 was prepared in the same manner as in Example 1, and Example 1. A button type battery similar to the above was manufactured. 50 this battery
Discharge under the resistance of 0kΩ and 100kΩ, and 500kΩ
When the final voltage is 2.3V and 100kΩ, and the final discharge voltage is 2.0V, the iodine utilization rate is 500k.
85% for Ω discharge 65 for 100 kΩ discharge
%Met.

Example 3. Poly (2,5-thienylene) is mixed with 5% by weight of carbon powder (Ketchen Black sold by Lion Corporation). 4 for this mixture and iodine (poly (2,5-thienylene))
Double the weight) was taken in a glass tube, the gas in the glass tube was removed by a vacuum pump, and the glass tube was sealed. This glass tube was used in Example 1. In the same manner as above, by heating in an oil bath at 150 ° C for 15 hours, poly (2,5-thienylene) and iodine are mixed with 1: 1.
A substance consisting of 5% by weight of carbon powder to poly (2,5-thienylene) and a composition containing it in a weight ratio of 4 was obtained (note that some of the iodine may be adsorbed by the carbon powder). ). This material was used as a positive electrode active material and a lithium plate was used as a negative electrode active material. A button type battery similar to the above was manufactured. When this button-type battery was continuously discharged under a resistance of 500 kΩ as in Example 1, a closed circuit voltage of 2.8 V was obtained at the start of discharge. When the discharge was stopped when the closed circuit voltage reached 2.3 V, 62% iodine utilization was obtained.

Example 4. Poly (3-methyl-2,5-thienylene) (Bull.Chem.So
c. Jpn., 56 1497 (1983)) with 5% by weight of carbon powder (Ketjen Black sold by Lion Corporation). This mixture and iodine (poly (3-methyl-2,5-thienylene))
9 times the weight) was taken in a glass tube, and the gas in the glass tube was removed by a vacuum pump to seal the glass tube. By heating this glass tube in an oil bath at 150 ° C. for 15 hours, a composition containing poly (3-methyl-2,5-thienylene) and iodine in a weight ratio of 1: 9 and poly (3-methyl-thiophene) was added. 2,5
A material consisting of 5% by weight of carbon powder (thienylene) was obtained (some iodine may be adsorbed on the carbon powder). This material was used as a positive electrode active material and a lithium plate was used as a negative electrode active material. A button type battery similar to the above was manufactured. When this button-type battery was continuously discharged under a resistance of 500 kΩ, a closed circuit voltage of 2.8 V was obtained at the start of discharge. Example 1 based on the amount of electricity flowing until the closed circuit voltage reaches 2.33V. When the iodine utilization rate was calculated in the same manner as above, it was 63%. In this example, a battery that functions normally even when no carbon powder was added was obtained.

Example 5. By adding a Ni complex as a catalyst to a solution obtained by reacting 2,5-dibromo-N-methylpyrrole and magnesium at a molar ratio of 1: 1 in tetrahydrofuran (patent 951386), poly (N-methyl- 2,5-Pyrrolylene) was obtained. Take 9 times as much iodine as the weight of poly (N-methyl-2,5-pyrrolylene), add both into a glass tube, remove the gas in the glass tube with a vacuum pump, and then seal the glass tube. did. This glass tube was heated in an oil bath at 150 ° C. for 15 hours to obtain a composition comprising both of the above, and 77.4 mg of this composition was used, and a lithium plate was used as a negative electrode. A button type battery similar to the above was manufactured. When this button-type battery was continuously discharged under a resistance of 500 kΩ, a closed circuit voltage of 2.8 V was obtained at the start of discharge, and the closed circuit voltage was 2.3 V or more for a long period of 1000 hours or more.

Comparative Example A battery was made in the same manner as in Example 1 except that polypyrrole was used instead of poly (2,5-thienylene). The closed circuit voltage at the start of discharge was 2.65 V, and after the start of discharge
It reached 2.3V within 1000 hours.

The performance of the batteries obtained in the above Examples 1 to 5 and Comparative Example is summarized in the table.

 ─────────────────────────────────────────────────── --- Continuation of the front page (56) Reference JP-A-56-149774 (JP, A) JP-A-58-112247 (JP, A) JP-A-57-13670 (JP, A) JP-A-57- 34677 (JP, A) JP 57-40870 (JP, A) JP 57-154774 (JP, A)

Claims (1)

[Claims] 1. A composition comprising a polymer compound selected from poly (2,5-thienylene) or a derivative thereof and poly (pyrrolylene) or a derivative thereof and iodine is used as a main component of a positive electrode mixture, and lithium is used as a negative electrode. A primary battery comprising an active material and a solid electrolyte as an electrolyte interposed between a positive electrode and a negative electrode.