JPS63285864A - Electrode for battery - Google Patents

Abstract

PURPOSE:To increase the capacity of a battery and moreover to make high rate discharge possible by supporting a composite comprising conductive polymer and anionic polymer electrolyte in a porous conductor. CONSTITUTION:This electrode is prepared by supporting a composite comprising a conductive polymer (A) and an anionic polymer electrolyte (B) in a porous conductor (C). Polypyrrole and others are used as the polymer (A), polystyrene sulfonic acid anion and others as the electrolyte (B), and a felt-shaped molding made of carbon fibers formed by vapor phase deposition as the conductor (C). The composite is supported in the conductor (C) by using the conductor (C) as an anode and electrolyzing an aqueous solution containing monomers of the polymer (A) and the electrolyte (B) as an electrolytic solution to form the electrode. The electrode obtained is used in a battery using a metal such as lithium as the counter electrode.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a novel polarization for sulfur ponds.

[Conventional technology and its problems]

Conventionally, as a battery using a conductive polymer as a positive electrode active material, 8hynthetic Metals, vol.
, /♂, part l, 2 jri (/977), are listed. The conductive polymer in this battery is Volivil, and the negative electrode active material is lithium.

Since the polypyrrole takes in and releases anions from the supporting electrolyte through redox, the supporting electrolyte accumulates between the two electrodes as the battery discharge progresses. In order to dissolve the supporting electrolyte (second), a large amount of organic solvent is required. However, organic solvents generally have a weak ability to dissolve the electrolyte, and even if they dissolve, it is difficult to obtain sufficient conductivity. (=In order to obtain a durable battery, special measures such as making the liquid layer extremely thin are required, and therefore a large amount of solvent cannot be used, which conflicts with the above requirements.For the above reasons, it is necessary to make the battery system lightweight. It is difficult to obtain a battery that can withstand a large capacity and a heavy load.

The inventors of the present invention have conducted extensive research to solve the problems of the conventional technology, and have found that a complex consisting of a conductive polymer and an anionic polymer/adduct can undergo cations due to redox. Focusing on the property of releasing and taking in ions, when this composite is used as a positive electrode of a 7th battery or a 2nd battery by supporting a porous conductor (2), the cations generated from the negative electrode active material during discharge are It was discovered that the battery is contained in the composite and does not accumulate in the electrolytic solution, so a battery can be constructed with a small amount of solvent, and that a large current can be extracted because the positive electrode has a low internal resistance, and in completing the present invention. It's arrived.

[Means for solving problems]

The present invention is a battery electrode characterized by a structure in which a porous conductor supports a composite consisting of a conductive polymer and an anionic polymer electrolyte.

In the present invention, a conductive polymer is a polymer that exhibits conductivity because its main chain is composed of a π-conjugated system. For example, repeating units of polyacetylene, poly(/, hebutadiyne), polydiacetylene, polypyrrole, and polymers (R+ represents 1 kyoko hydrogen, an alkyl group, or an aryl group, and R4 represents an alkyl group or an aryl group) Represents: R2, R3, RII, R,, R7
and R8 represents a hydrogen atom, an alkyl group, an aryl group, a carboxyl group or a sulfonic acid group. ) Poly(pyrrole derivative), polythenylene, repeating unit of polymer (R9 to RI4 are hydrogen atoms, alkyl groups, aryl groups,
Represents a carboxyl group or a sulfonic acid group. ) poly(chenylene derivative), poly(p-phenylene), bo9(m-phenylene), poly(p-phenylene sulfide), poly(m-phenylene sulfite)
, poly(p-phenyleneoxy F)1. j? ! J(p-
phenylene vinylene), polyaniline, and poly(aniline derivatives) in which the repeating unit of the polymer is represented by (R111 to R14 represent a hydrogen atom, an alkyl group, an aryl group, a carboxyl group, or a sulfonic acid group). Among these, especially polypyrrole, poly(virol derivatives), polyaniline, poly(aniline derivatives)
is preferred.

In the present invention (2), an anionic polymer electrolyte is a polymer that becomes an anion through ionic dissociation.

Examples include polyacrylate anion, polymethacrylate anion, polystyrene sulfonate anion, polyethylene sulfonate anion, polyvinyl sulfate anion, poly(fluorocarbon sulfonate anion), and the like. Among these, particularly preferred are polystyrene sulfonate anions, polyethylene sulfonate anions, polyvinyl sulfate anions, and polymers in which the hydrogen atoms of these polymers are substituted with fluorine atoms.

In the present invention (2), a porous conductor refers to its surface and/or
or have a large number of gaps or pores inside, and therefore (
= very large surface area) and has electrical conductivity. Examples include woven fabrics made of carbon fibers, carbon quiskers, metal fibers, metal quiskers, etc.; sheet-like or lump-like molded products such as paper, non-woven materials, and felt; sheet-like and plate-like products made of carbon powder and metal powder; Alternatively, it may be a block-like molded product.

Among these, porous conductors made of carbon fibers, carbon quiskers, and carbon powder are preferred, and porous conductors made of vapor-grown carbon fibers are particularly preferred.

In order to create the porous conductor, for example, if a fibrous material is used, the mechanical entanglement of the material is used,
It may be formed into the above-described shape, and a binder may be used at this time if necessary.

Further, when a powder material is used, a method of molding a powder battery active material, for example, a method of compression molding using a binder may be used.

The battery electrode of the present invention is prepared by electrolysis. In other words, a porous conductor is used as an anode, and an aqueous solution containing a conductive polymer and a hyanionic polymer electrolyte is prepared. When electrolysis is carried out using an electrolytic solution, a composite consisting of a dihydrogen polymer and an anionic polymer electrolyte is supported on the porous conductor. When using the above method, the monomer for the conductive polymer may be any monomer that can be prepared in an aqueous solution; for example,
The general formula is (R+ represents a hydrogen atom, an alkyl group or an aryl group. R4 represents an alkyl group or an aryl group. R2
, R1, R1, -1R, and Rs represent a hydrogen atom, an alkyl group, an aryl group, a carboxyl group, or a sulfonic acid group. ), or aniline or aniline derivatives whose general formula is R-box (R15 to Rj14 represent a hydrogen atom, an alkyl group, an aryl group, a carboxyl group, or a sulfonic acid group). .

When virol is used as a conductive polymer, the concentration of virol in the electrolyte is θ,j~! Weight percent is preferred. In addition, the concentration of anionic polymer electrolyte in the electrolyte is 7~
70% by weight is preferred.

The current density is preferably 7.0 to 20 mAIcrA. The temperature is one/! -, gθ°C is preferred. Since the battery electrode prepared in this manner has the function of releasing or taking in cations as a result of redox, it is possible to construct a battery using a metal electrode as a counter electrode. For example, when lithium is used as the electrode, the organic solvent that separates the positive and negative electrodes is simply a passageway for lithium cations, so only a small amount is required. It is lightweight (large capacity) because the resistance of the electrolyte can be lowered.
Furthermore, a battery that can withstand heavy loads can be obtained. Furthermore, since the battery electrode of the present invention maintains a porous structure, its internal resistance is less than 1, which is advantageous as a battery electrode for heavy loads.

〔Effect of the invention〕

The battery electrode according to the present invention has the function of releasing or taking in cations during oxidation-reduction and has low internal resistance, so when a battery is constructed using a metal such as lithium as a counter electrode, it has a large capacity and can withstand heavy loads. It is possible to construct a durable primary or secondary battery.

〔Example〕

The present invention will be explained in more detail below with reference to Examples.

Example/ As an anode, vapor grown carbon fiber (hereinafter referred to as
It is abbreviated as VGCF. ) felt-like molded body (/
j lie×／j■, thickness approx. 0.3 all, weight 70~)
using a platinum plate (/ j m X/ ! r
m) using virol 0. Contains ♂chi, polystyrene sulfonate sodium WAMCO, and Zyong/j? An aqueous solution of /θ
Electrolyzed for mAllt hours, a polypyrrole/polystyrene sulfonic acid complex (hereinafter abbreviated as PPY/R88) was obtained.

) was supported on VGCF, and the magnetic pole was vacuum-dried at 790° C. for 3 hours to obtain the intended battery magnetic pole. ppy-ps
The supported amount of s is 79. It was ■.

A battery was assembled in an argon atmosphere using this electrode as a positive electrode, a negative electrode formed by pressing lithium onto 808 net, and a /mot/l propylene carbonate solution of lithium perchlorate as an electrolyte solvent.

Note that Lyticum Ryugyoku was incorporated into the battery as a reference electrode.

Discharging current (ID) = 2 mA, charging current (10
) = 2 mA, upper end potential (Vu) = 3. Otsu V (
Value from reference Li electrode), lower end potential CVL) = /,
! ■When charging and discharging were repeated at (value from the reference Li electrode), it showed stable characteristics over jθ psi,
The capacitance density of the 88-supported VGCF electrode exhibited a gradient of Q,2Ab. Further, the coulombic efficiency of charging and discharging was 700%. A part of the charge/discharge characteristics is shown in Figure 1 (2).

Example 7 A battery electrode was prepared in the same manner as in Example 2, and a battery was constructed. The electrolytic conditions and battery characteristics at the time of preparation are shown in Table 1.

The charge/discharge test was In =2mA, io ==4tmA,
When conducted at Vu = 3.7 V, VL = /, j V, it showed stable characteristics, and the Coulombic efficiency was lθθ
It was Chi.

Examples 3 to 5 Electrodes for batteries were prepared in the same manner as in Example 1 under the conditions shown in Table 1, and batteries were constructed. The battery was evaluated under the two electrode evaluation conditions shown in Table 1. The results are shown in Table 7.

Example 2 Electrodes for a battery were prepared in the same manner as in Example under the conditions shown in the table, and a battery was constructed. The battery was evaluated under the electrode evaluation conditions shown in Table 1 (2), and the results are shown in Table 1.

Further, the discharge characteristics are shown in FIG.

Examples 7 to IO Battery electrodes were prepared under the conditions shown in Table 7 in the same manner as in Example 1, and batteries were constructed. The battery was evaluated under the two electrode evaluation conditions shown in Table 1. The results are shown in Table 7.

Examples//~/6 A battery electrode was prepared and a battery was constructed using the same method as in Example (2) under the conditions shown in Table 7. The battery was evaluated under the electrode evaluation conditions shown in Table 1. , the results are shown in Table 7.

(Margin below)

[Brief explanation of the drawing]

FIG. 1 shows the charging and discharging characteristics of the battery in Example/,
FIG. 2 shows the charging and discharging characteristics of the battery in Example B.

Claims (1)

[Claims] A battery electrode characterized by a structure in which a porous conductor supports a composite consisting of a conductive polymer and an anionic polymer electrolyte.