JPS60182661A - Electrode - Google Patents

Abstract

PURPOSE:To obtain a pollution-free secondary battery having large capacity, light weight, compact size, and safety by using onium salt prepared by nitrile and iodine cation as a positive active material. CONSTITUTION:Onium salt prepared by nitrile and iodine cation is used as a positive active material. For example, a cylindrical glass filter is used as a separator. The separtor is put in a glass beaker and the inside of the separator is used as a positive electrode chamber. A platinum plate is used as positive electrode and an aluminium plate is as negative electrode. Acetonitrile is used as nitrile and LiBF4 is as supporting electrolyte. Iodine, LiBF4, and acetonitrile are put into the positive electrode chamber, and LiBF4 and acetonitrile are put into the negative electrode chamber to form a secondary battery.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a secondary battery, and more specifically, it is an object of the present invention to provide a pollution-free battery that can be discharged for a long time, is lightweight, easy to downsize, and highly safe.

Light weight and miniaturization based on recent technological advances in various fields is strongly desired in the battery sector as well, and for this purpose there is a strong demand for the development of batteries with as high an energy density as possible. However, lead-acid batteries and alkaline batteries, which are currently the mainstay of secondary batteries, have theoretical limits, making it extremely difficult to obtain the required high energy density. difficult to achieve the objective. In addition, attempts are being made to use chlorine or bromine as positive electrode active materials for the purpose of obtaining new secondary batteries, but in this case, it is difficult to use active halogens directly in liquid or gaseous form. Due to the difficulty and safety issues, it is far from being put to practical use, and it is also difficult to make it lightweight and compact.

As a result of intensive research to reduce the dangers of directly using corrosive and highly toxic / We have discovered that by using an onium salt produced from the above as a positive electrode active material, the above-mentioned problems can be solved, and a secondary battery that is lightweight, compact, and highly safe can be obtained. The invention has been completed.

That is, the present invention relates to a battery characterized in that an onium salt produced from a nitrile and an iodo cation is used as a positive electrode active material.

According to the present invention, upon charging, iodo cations generated from iodine or iodo anions coexist with nitrile at the positive electrode and are captured by nitrogen atoms, which are constituent atoms of monotrile, to form an onium salt. It was discovered that the onium salt produced here was a concubine and could be effectively used as a positive electrode active material for secondary batteries because of its good reversibility in redox reactions. Therefore, a battery using this onium salt as a positive electrode active material can be said to be completely new. And to the invention! If so, halogen can be used safely and effectively, and a secondary battery with high energy density can be provided.

The battery of the present invention is composed of a positive electrode, a negative electrode, an onium salt as a positive electrode active material, a solvent, a supporting electrolyte, and if necessary a separator, etc., and the onium salt generates 2l-'J and iodo cations. iodine or (and) an iodine compound. 2L used to form the onium salt that is the positive electrode active material used in the present invention
-IJ is not particularly limited as long as it has the property of forming an onium salt with an iodo cation; for example, at least one type of aliphatic nitrile or polymer nitrile is used. The aliphatic nitrite used in this case is a nitrile having a saturated alkyl μ group having 1 to 5 carbon atoms, or a dinitrile having 2 to 4 methylene groups, and specifically, for example, acetonitrile, Examples include propionitrile, isobutyronitrile, succinonitrile, and adiponitrile. There are no particular restrictions on the structure of the main chain of the polymer nitrile as long as it is a polymer having a nitrile group in its side chain. Examples include copolymers with the like.

A wide range of iodine compounds that produce iodo cations can be used, such as iodine itself or its hydrides, alkali metal iocides, tetraalkylammonium iodides, etc. Examples include hydrogen iodide, lithium iodide, sodium iodide, potassium iodide, tetraethylammonium iodide, tetrabutylammonium iodide, triethyloctylammonium iodide, and iodine itself.

These may be used alone or in combination as two or more.

The molar ratio of iodo cation and nitrile group can be freely set within a wide range (3N/I+ ratio is 1).
~1×10 gives good results.

As the supporting electrolyte in the present invention, an alkali metal salt or a tetraalkylammonium salt is used. These are those that have traditionally been used as supporting electrolytes, such as borofluoric acid, perchlorinated wood acid, hydrogen iodide, hexafluorophosphoric acid, methanesulfonic acid, )/enesulfonic acid, etc. Examples include salts such as Examples of the alkali metal in this case include Li, Na, and the like.

The amount of these salts to be used is from an equimolar amount to 1 molar amount to the amount of iodo compound used to generate the iodo cation.
A range of 0 times the amount is desirable, but it is not limited thereto.

As the solvent used in the present invention, the nitriles and mixtures thereof used for producing the positive electrode active material may be used as they are, but an aprotic polar solvent can be used together with these nitriles.

Examples of the aprotic polar solvent include, but are not limited to, dimethylformamide, dimethylacetamide, pyrrolidone, N-methylpyrrolidone, dimethylsulfoxide, hexamethylphosphortriamide, propylene carbonate, and γ-butylofuctone. .

The positive electrode used in the present invention can be made of any conventionally known material and shape. For example, rod-shaped, plate-shaped,
Alternatively, conductive materials such as carbon or platinum in various forms such as powder can be exemplified as desirable examples, but low iron, nickel, copper, etc. can also be used by coexisting with carbon.

As a general rule, a desirable material for the negative electrode is KUMU, as long as it is a conductive material. Note that when a powder is used as the material for the positive electrode or the negative electrode, it can be used in the form of a paste or formed into an appropriate shape.

The separator is used when necessary between the positive electrode chamber and the negative electrode chamber, and there are no particular restrictions on the material or form. The following are desirable, but not limited to these.

The battery according to the present invention, which uses an onium salt produced from nitrile and iodo cation as a positive electrode active material, is completely new, has a high energy density, can be discharged for a long time, and is lightweight and compact. It is an extremely advantageous battery that is easy to use, highly safe, non-polluting, and inexpensive.

Note that the battery of the present invention is not necessarily limited to miniaturization, but is also suitable for large-sized and large-capacity batteries.

Viewed from its operating mechanism, the battery of the present invention can be said to be a double battery that is a combination of a primary battery and a secondary battery. That is, for example, a primary battery can be formed by using iodine as a positive electrode active material and lithium as a negative electrode. Various primary batteries have been studied using this principle, but all of them are special batteries that can draw only an extremely weak current.

However, by combining a positive electrode prepared in the present invention, such as a positive electrode molded from powdered gutsphite, powdered polyacrylonitrile, and iodine, with a lithium negative electrode, a primary battery with an inter-terminal voltage of 8.2 volts can be obtained, and a large current can be easily extracted. be able to. Next, when charging is performed using the same positive electrode and a negative electrode such as 7μ minicum or lithium, a voltage between the terminals of 4.2 to 4.4 volts is obtained, and -
It can draw out a large current several times that of a secondary battery.

The present invention will be explained in more detail with reference to Examples below, but the present invention is not limited by these Examples.

Example 1 A cylindrical glass filter (diameter 4 Q
ynm) and place it in a glass cylindrical beaker (1
007ff/). Inside the separator! Positive electrode (96mm x 20m)
m), a ρ minicum plate (20 mm x 20
mm) is used. Acetonitrile as nitrile,
Lithium boron tetrafluoride (LiBF4) is used as a supporting electrolyte. '76.2mf Noyoto, 1.5 in the positive electrode chamber
f! 17) Place LIBF, 20 ml of 7-tz tonitrile, and 1.51 LiBF4 and 20 ml of acetonitrile in the negative electrode chamber.

Next, charging is performed at a constant current of 50 mA until an amount of electricity of 1.5 F/mol (F/mol) is applied to the iodine. Voltage between open terminals 4, 2 when charging is completed
■It is. The initial short circuit current of this battery is l, 75A/dm
Met. The results of the discharge test under a constant load of 61 ohms are shown in Table 1.

Table 1 Example 2 The cell is a ceramic container with a cylindrical bottom (
25 mm in diameter), and the same glass container as in Example 1 was used. A rod-shaped graphite (diameter Bmm, length 50 mm) is used as the positive electrode, and a lithium plate (50 mm x 90 mm') is used as the negative electrode. A paste of 1.2 TI of iodine, t s ml of acetonitrile, and 1.18 f of LiBF4.10y powdered gutsphite is placed in the positive electrode chamber. In the negative electrode chamber (2), put LiBF4 (1.5 y cr) and 20 ml of acetonide IJ/S. When charging was performed with a constant current of 100 mA and the amount of electricity was IF/mol for iodine, the voltage between open circuit terminals was 4.25 V, and the initial short circuit current was 805 V.
It is mA.

Example 8 The separator is the same bottomed cylindrical ceramic container as in Example 2. This has an inner diameter of B □ mm and a depth of 76 mm.
into an aluminum cylindrical container. A gutsuphite rod (8 mm x 50 mm) was used as the positive electrode, and 1 piece was placed in the positive electrode chamber.
．． 27F iodine, 20ml acetonitrile, 1.5
Add a mixed paste of 1 part of LiBF and 10 f of powdered gutsphite. The aluminum container itself is used as the negative electrode, and the negative electrode chamber contains 1.517) LiBF4.20 mtl.
Add a paste of 7-tc/L/L and 8f of powdered gutsphite.

Charging was performed with a constant current of 100 mA, and the I
Charge with an amount of electricity of F/mol. After charging is completed, the open circuit voltage between the terminals is 4.10 V, and the initial short circuit current is 825 mA.

Example 4 The same separator and glass container as in Example 1 are used. Platinum plates (20 mm x 20
mm) is used. The positive electrode chamber, which is inside the separator, contains powdered polyacrylonitrile/l/l with a molecular weight of approximately 120,000 and 1.59 f, 25.4 ml of iodine, 20 ml of dimethylformamide, and 1.5 f of LiBF4. .5 f Add OLiBF4 and 20ml dimethylformamide. Iodine line Lte 1.5 F/m
ol Charge the chisel capacity with bomAo constant current. At this time, the voltage between the open circuit terminals was 8.8V. Further, the initial short circuit current is 1.05 A/dm.

The results of the 51 ohm constant load discharge test are shown in Table 2.

Table 2 Example 5 The same separator, container, and positive electrode as in Example 2 were used, and prusminium (50 myn x 90 mm) was used as the negative electrode. The positive electrode chamber contains 1.27 FI of iodine, 1.13V of LiBF4, 2f of polyacrylonitrium μ powder with a molecular weight of approximately 120,000, 10f of graphite powder, and 15 m
1 of dimethylformamide is mixed into a paste. In the negative electrode chamber, 20 ml of glue methylformpamide, 1
．． A paste consisting of 51 LiBF4 and 10 f graphite powder is introduced.

At a constant current of 100 mA,
Fully charge the electricity i. Open circuit voltage after charging completion 4
．． 10 V, initial short circuit current 115 mA.

After sufficiently adjusting the T of 0.05 N polyacrylonitrile powder (Molecular Fishing 120,000), it is molded into a disk shape with a diameter of 15 mm and a thickness of 2 mm under a pressure of 500 mm/cm. A platinum plate (10 mm x 29 mm) was crimped onto this disk as a current collector plate to serve as the positive electrode, and aluminum (10 mm x 20 mm) was used as the negative electrode. Next 5
A glass beaker containing 0 Mg is used as a container, and the positive and negative electrodes are placed in a solution consisting of 40 ME dimethylformamide and 8 f LiBF4, and a gaff fiber fRp paper is placed in the middle to prevent contact between the two. Fully charge the iodine with a constant current of 59 mA to an amount of electricity of 1.5 F/mol. After charging is completed, the voltage between open circuit terminals is 4,4■, and the initial short circuit current is IBA/dm with respect to the positive electrode.

Example 7 A positive electrode prepared in the same manner as in Example 6 was used, and a lithium plate (20vxnxx2o mm) was used as a negative electrode. Glass fiber IaP paper was inserted between the positive electrode and the negative electrode as a separator, and the whole was placed in a solution consisting of 20 ml of dimethylformamide and 1.5 g of LiB1'4E. After charging the iodine with an electrical quantity of IF/mol with a constant current of 59 mA and removing the solution, a solid-state ion pond is obtained without using a molten metal. The open circuit terminal voltage was 8.8 V, and the initial short circuit current was 875 mA/dm.

(that's all)

Claims (1)

[Claims] A battery characterized in that an onium salt produced from nitrile μ and an iodo cation is used as a positive electrode active material.