JPS5966058A - Secondary battery - Google Patents

Abstract

PURPOSE:To obtain a secondary battery with improved charging/discharging characteristics by using as the positive or negative pole, polymer substance where the principal chain is conjugated by the pi electron and this principal chain is bridged by the pherocene functional group. CONSTITUTION:A secondary battery in which polymer substance where the principal chain is conjugated by the pi electron and this principal chain is bridged by the pherocene functional group is used for the positive or negative pole, while a solution dissolving a solvent having the negative ion and positive ion which are absorbed or released in/from this polymer by charging/discharging process is used for the electrolyte. When a electrode obtained by such polymer material is used for the one or both of the positive and negative poles, the charging/discharging characteristics of secondary battery can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a secondary battery using a polymeric substance as an electrode material.

Conventional PLTF) structure and its problems Recently, it has been known that doping a high molecular weight polymer with a certain substance improves its electrical conductivity, and that it eventually exhibits metallic conductivity. Molecular substances are called synthetic metals. Typical examples are polyacetylene and polyphenylene.
Electrons are delocalized between the main chains due to conjugated double bonds.

By doping it with a certain type of substance, it exhibits high electrical conductivity.

A new publication using this type of polymer material as an electrode material is described. When a polymeric material is used as the positive electrode, the charge-discharge reaction is a charging reaction due to the incorporation of anions (doping) into the electrolyte of the polymeric material, and a discharging reaction due to the release of anions (undoping). When used, a charging reaction occurs due to the uptake of cations, and a discharging reaction occurs due to the release of cations.

The charge/discharge reaction will be shown below when a solution prepared by dissolving lithium perchlorate in, for example, propylene carbonate is used as a solution in polyacetylene (CH) n-' as a polymeric substance.

Positive electrode (CH)n-+-nχ(CAO4-) Negative electrode (CH)y)-)-nX+9+nXLi'-As described above, a polymer substance functions as a positive electrode or a negative electrode, so it cannot be combined with other negative electrodes or positive electrodes. Of course, a secondary battery can also be constructed by a combination of polymeric substances.

In addition to the above, known polymeric substances of this type include polyphenylene sulfide, polypyrrole, and polyacetylene in which some of the hydrogen atoms have been substituted with halogen atoms, alkyl groups, phenyl groups, alkylphenyl groups, herophenyl groups, etc. It is being

On the other hand, when a polymer material is used as the negative electrode, the electrolyte used in combination with it is lithium perchlorate (t, 1c
Organic electrolytes are known in which a lithium salt such as 6o4)-lithium borofluoride (LiBF4) or lithium hexafluorophosphate (LiPF6) is used as a solute and propylene carbonate or detrahydrofuran is used as a total solvent.

However, when the above-mentioned polymeric substances were used for electrodes, there was a drawback that high rate charging and discharging was difficult.

OBJECTS OF THE INVENTION An object of the present invention is to provide a polymer material electrode that is capable of high rate charging and discharging.

Structure of the Invention The present invention utilizes a polymeric substance such as polyacetylene or polynitrile, whose main chain is conjugated with π electrons and whose main chain is cross-linked with a ferrocene functional group, as a positive or negative electrode, for charging and discharging. It is characterized by being composed of electrolyte M1 in which solutes are dissolved, including anions and cations that are incorporated into or released from polymeric substances.

The reason why the polymeric substance of the present invention has excellent charge/discharge characteristics is considered to be as follows. That is, for example, by connecting the main chains of polyacetylene with a ferrocene functional group, the π electrons of the polyacetylene arranged in a plane have a sandwich structure, and the π electrons and the d-axis path of iron form a hybrid VL path. The charge/discharge characteristics of the electrode are improved by performing a phase-4 action through the ferrocene present in the ferrocene.

Description of Examples The structure of the polymer substance used in the examples is shown below and will be referred to as polymer (1).

Examples of the positive electrode of a secondary battery are shown below.

Example 1 Propylene carbonate in which 1 mol/l of lithium perchlorate was dissolved in an electrolytic solution was used. A lithium plate having a size of 2 cm x 2 C711 and a thickness of 1 mm was used as a counter electrode, that is, a negative electrode, and a lithium plate was used as a reference electrode. As the positive electrode material, polyacetylene as a comparative example and the polymer (1) described above were used. For polyacetylene, use a film with size 2 cIILX 2 Cnl + weight 50 mg, and for polymer (1), use powder 60 ml f size 2α
A compression molded sheet of X2cnL was used.

As shown in FIG. 1, these positive electrode particles 1 were adhered to a titanium plate 3 serving as a current collector using a carbon paint 2 to form an electrode.

All charge/discharge tests were conducted at 20°C. Charging is carried out until the potential of the positive electrode becomes -1-4.2V with respect to the reference electrode, and discharge is carried out until the potential of the positive electrode becomes -1-4.2V with respect to the reference electrode. I went all the way to OV.

The first cycle of charging and discharging was performed at ○j2mA.

All charging and discharging from the second cycle onwards were performed continuously at 4 mA. FIG. 2 shows the charging curve and discharging curve of each positive electrode in the 1st and 10th cycles.

In the figure, A is polyacetylene and B is polymer (1).

Table 1 also shows all the charging capacity and discharging capacity in the 10th cycle.

Table 1 Example 2 Positive + iff with the same configuration as Example 1 is used, and 1 is used for the electrolytic/lysis method.
A mol/4 zinc iodide (ZnI2) aqueous solution was used.

A curved lead plate was used as the counter electrode, that is, the negative electrode, and a saturated permanent electrode was used as the reference electrode.For charging and discharging, the positive electrode was saturated at -1-o, 16 V with respect to the saturated earth and water electrode. The discharge was carried out until the voltage reached -0.24V.The first cycle of charging and discharging was carried out at 0-12 mA, and the charging and discharging after the second cycle were all carried out at 4 mA.Table 2 shows , the charging capacity and discharging capacity of each positive electrode in the 10th cycle are shown.As described above, polymer (1) exhibits excellent charging and discharging characteristics even when aqueous solution 'o' is used as the electrolyte.

From the examples in Table 2, when polymer (1) is used as a positive electrode, it is possible to take in and release anions such as perchlorate ions and iodine ions in an organic electrolyte or an aqueous solution as a charge/discharge reaction. It can be seen that it shows superior performance compared to conventional polyacetylene. Examples as negative electrodes will be described below.

Example 3 An electrode as shown in FIG. 1 was constructed as a negative electrode in the same manner as shown in Example 1. However, in the electrode configuration shown in FIG. 1, the carbon paint in No. 2 was platinum-based A1, and the current collector in No. 3 was a nickel plate instead of the titanium plate. The counter electrode, that is, the positive electrode, is
7) was used. Titanium disulfide 11 and acetylene black as a conductive material 0.1,! 7 and [' Add 0.19 f of tetrafluoroethylene resin as adhesion agent and mix the mixture at a pressure of 1 ton with a size of 2 C7n x 2 Cm.
- Compression molded into a flat shape. A lithium plate was used as the reference electrode 7. Propylene carbonate in which 1 mol/β lithium hexafluorophosphate was dissolved was used as the electrolyte. Charging and discharging are performed until the potential of the negative electrode becomes +0.2 vV with respect to the lithium reference electrode. I went with the ox that became OV. The charging/discharging current of the first cycle was 0.12 mA, and charging/discharging was performed at 4 mA from the second cycle onward. FIG. 3 shows the charge/discharge curves of each negative electrode in the first o cycle. In the figure, A' is polyacetylene and B' is polymer (1). Table 3 shows the charging capacity and discharging capacity in the 1st and 10th cycles.

Table 3 In this example, titanium disulfide was used as the counter electrode, that is, the positive electrode, and the characteristics of the negative electrode were evaluated using the change in potential with respect to the lithium reference electrode as a parameter.

This is because the characteristics of the negative electrode can be clearly determined by this method. Even when the same electrode as in Example 1, that is, a polymer was used for the positive electrode, the characteristics of the negative electrode were the same.

Furthermore, when the charging and discharging characteristics of polymeric substances as negative electrodes were all investigated using an aqueous solution containing dissolved zinc iodide as an electrolyte, polymer (1) was superior.

From the above, even when polymer (1) is used as a negative electrode, it is possible to take in and release cations such as lithium ions and zinc ions in an organic electrolyte or an aqueous solution as a charge/discharge reaction. It can be seen that it shows superior performance compared to polyacetylene.

In the following examples, a polymer material having a structure in which polyacetylene is cross-linked with ferrocene is used. In addition, as a polymer material whose main chain is conjugated with π electrons and whose main chain is cross-linked with ferrocene, we have investigated a polymer material in which polynitrile is cross-linked with ferrocene. The discharge characteristics were shown. The molecular structure of this polymeric substance is shown in (11).

In the following margins, when a polymer material whose main chain conjugated with π electrons is cross-linked with ferrocene is used for the positive or negative electrode,
It was shown that its charge-discharge characteristics were improved. From this, it is clear that the charge/discharge characteristics of the secondary battery are improved by using it for either or both of the positive electrode and the negative electrode of the secondary battery.

Effects of the Invention According to the present invention, it is possible to improve the charging and discharging characteristics of a secondary battery using a polymeric substance as a positive electrode and/or a negative electrode.

[Brief explanation of the drawing]

Figure 1 is a longitudinal cross-sectional view of the electrode used in one example, Figure 2 is a diagram showing the charge-discharge curves of various positive electrodes in an organic electrolyte, and Figure 3 is a diagram showing the charge-discharge curves of various negative electrodes in an organic electrolyte. Charging and discharging curves are shown. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Charging time (time) Figure 3 Discharging time (time)

Claims (1)

[Claims] A positive electrode or a negative electrode made of a polymeric substance that reversibly takes in and releases anions or cations through charging and discharging, and an electrolytic solution containing the anions or cations, wherein the polymeric substance is conjugated by π electrons. A secondary battery characterized by a structure in which the main chains of the two main chains are bridged by ferrocene.