JPS6282672A - How to charge a non-aqueous secondary battery - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention uses an oxidized polymer of an aniline compound for the positive electrode, and (i) a light metal, (ii) an alloy of light metal, or (ii) a negative electrode for the negative electrode.
Regarding a method for charging a non-aqueous secondary battery using i) a conductive polymer or (iv) a composite of a light metal or an alloy of light metal and a conductive polymer, it particularly extends the repeated life of the battery,
The present invention also relates to a method for charging a non-aqueous secondary battery that provides a non-aqueous secondary battery with less self-discharge.

"Prior Art" So-called polymer batteries, in which a polymer compound having a conjugated double bond in the main chain is used as an electrode, are expected to be used as high energy density secondary batteries.

Many reports have already been made regarding polymer batteries, for example, BJ Nigley et al., Journal of the Chemical Industry, Chemical Communication, 1979.

Page 594 (P, J, Nigrey et al., J, C, S,
ChcmCommun, Yuwonggang 594), Journal Electrochemical Tuniati, 1981
, p. 1651 (Jl: electrochem, S
oc,,-Mon 381 1651), Japanese Patent Publication No. 56-1
No. 36469, No. 57-121168, No. 59-38
No. 70, No. 59-3872, No. 5'J-3873,
No. 59-196566, No. 59-196573, No. 59-203368, No. 59-203369, etc. can be mentioned as some of them.

In addition, there have already been proposals to use polyaniline, which is obtained by oxidative polymerization of aniline, which is a type of military polymer, as an electrode for aqueous or non-aqueous batteries [A.G.・Preblinz, Volume 25, Number 2. Page 248 (i984) [A, G, HacDiarmid et al.
r Preprints, Wataru No., 2. 248(
(i984) Ko, Sasaki et al., Abstracts of the 50th Annual Conference of the Electrochemical Society, 123 (i983), Abstracts of the 51st Annual Conference of the Electrochemical Society, 228 (i984)).

[Problem to be Solved by the Invention 1] However, all of the conventionally known charging methods for batteries using polyaniline as the positive electrode of non-aqueous solvent batteries are constant current charging methods, so the practical current density ( 0.1mA/α2
(above)) and operate as a high energy density battery (high doping level), the charge voltage exceeds the stability range of the MwI liquid during charging, so there is a limit to the Nycle lifespan, and the self-discharge rate was not always satisfactory.

[Means for Solving the Problems] As a result of various studies aimed at solving the problems of the conventional method, the present inventors found that by adopting the charging method of the present invention, the purpose was extremely effective. The inventors have discovered that the following can be achieved, and have arrived at the present invention.

That is, in the present invention, an oxidized polymer of an aniline compound is used for the positive electrode, and (i) a light metal, (i1) an alloy of light metals,
(iii) Conductivity t! A method for charging a non-aqueous secondary battery using a polymer or (iv) a combination of a light metal or an alloy of light metals and a conductive polymer, characterized in that charging is performed by a current pulse method or a voltage pulse method. This relates to a method of charging a non-aqueous secondary battery.

The aniline compound used in the positive electrode of the non-aqueous secondary battery of the present invention has the following general formula (i) 2) and the structural formula (
3) by oxidative polymerization or oxidative co-compounding of at least one compound selected from 3).

[However, in the formula, R+ and R2 are an alkyl group having 5 or less carbon atoms or an alkoxy group having 5 or less carbon atoms, and X and Y are 0
, 1 or 2. ] Specific examples of aniline compounds represented by the general formula (i) or (2) include aniline, 2-mebou-aniline, 2,5-dimethylaniline, 2-me1-xy-aniline, 2,5 -dimethoxy-aniline, 0-7 enylenediamine, 3-methyl-1,2=diaminobenzene, and the like. Among the aniline compounds represented by formulas (i) to (3), aniline, 0-phenylenediamine, and triphenylamine are preferable, and aniline is preferable for 14.

The oxidized polymer or copolymer of the aniline compound used in the present invention (hereinafter referred to as oxidized polymer) can be produced by either an electrochemical polymerization method or a chemical polymerization method. be able to.

When electrochemical polymerization is used, the aniline compound is polymerized by anodic oxidation. For that purpose, for example 1
A current density of ~20 mΔ/Cm2 is used. In most cases, a voltage of 1 to 300 volts is applied. The polymerization is preferably carried out in the presence of an auxiliary liquid in which the aniline compound is soluble. Water or polar solvents can be used for this purpose. When using a solvent that is miscible with water, a small amount of water may be added.

Suitable organic solvents are alcohols, needles such as dioxane or tetrahydrofuran, acetone or ahitonitrile, benzonitrile, dimebylformamide or N-methylpyrrolidone.

Polymerization is carried out in the presence of a compounding agent. This is 8F I, AS Fi, and ASFi as anions.

5bFii, 5bCIJ-, PFi, (lloi.

means a salt containing

These salts contain cations such as protons (i-1
+), quaternary ammonium cation, lithium ion, sodium ion or potassium ion. The use of compounds of this type is known and is not the subject of the present invention. These compounds are usually used in the form of an oxidized polymer containing 20 to 100 mol % of the anionic compound-forming agent.

When producing the oxidized copolymer by a chemical polymerization method, for example, an aniline compound can be polymerized in an aqueous solution with a strong acid such as hydrochloric acid and an inorganic peroxide such as potassium persulfate. According to this method, the oxidized polymer is obtained in the form of a fine powder. Since a salt is present in these methods as well, the oxidized polymer becomes a complex compound with the corresponding anion.

The vine molded body used as an electrode can be heated by various methods. For example, in the case of anodizing an aniline compound, it is complexed with anions and an oxidized polymer in the form of the anode used is formed. If the anode has a flat shape, a flat layer of oxidized polymer is formed. When using a method for producing an oxidized polymer fine powder, this fine powder can be compression molded into a molded body under pressure and heat according to known methods. Often temperatures from room temperature to 300 °C and pressures from 10 to 10,000 Kg/cta2 are used. According to this known method for producing anionic complexed oxidized copolymers, shaped bodies of any desired shape can be obtained. That is, for example, a thin film, a plate or a three-dimensional shaped molding is used.

The oxidized polymer obtained by forming a complex compound with an anion may be used as it is as the positive electrode of the non-aqueous secondary battery of the present invention, or the product obtained by chemically or electrochemically removing the complexed anion may be used as the positive electrode. May be used.

As the supporting electrolyte of the electrolyte solution of the non-aqueous secondary battery of the present invention,
Alkali metal salts are used. Examples of the alkali metal of the alkali metal salt include li, Na and K metals, preferably li gold metal.

Typical anion components of the supporting electrolyte include, for example, C
10 I, PFi, AS Fi, As Fi.

SO3CFi, BFi, and BRi (however, R
is an alkyl group or aryl group having 1 to 10 carbon atoms), and the like.

Specific examples of alkali metal salts as supporting electrolytes include:
LiPFo, LiSbFa.

LiCρ04. L! AS Fo, CF3 SO3L
i.

Li BF4, l-i B (Bu)4゜Li B
(Ej)2 (BLI)2.

Na PFa, Na BF4, Na As Fo
.

Na B (Bu)4. KB (BIJ)4, KAs
Examples include Fa, but are not necessarily limited to these. 3 g of these alkali metals may be used alone or in combination of two or more.

The concentration of the alkali metal salt cannot be unconditionally defined because it varies depending on the type of oxidized polymer used in the positive electrode, the type of cathode, charging conditions, operating temperature, type of supporting electrolyte, type of organic solvent, etc., but in general is preferably within the range of 0.5 to 10 mol/fJ. The electrolyte may be homogeneous or heterogeneous.

Examples of organic solvents that can be used alone or in combination as a solvent for the electrolytic solution of the non-aqueous secondary battery of the present invention include the following -b.

Two alkylene nitriles, crotonitrile (liquid range, -51.1°C to 120°C) two trialkyl borates, trimethyl borate, (CH30)3B (liquid range, -29.3°C to 67°C) tetra Alkyl silicates: e.g., tetrametyl silicate, (CH30)4S!
(boiling point, 121°C) Nitroalkanes: e.g., nitromethane, CH3NO2 (liquid range, -17°C to 1008°C) Alkylnitrile: e.g., acetonitrile, CH3CN (liquid range, -45°C to 81.6°C) Dialkylamide: e.g. , dialkylamide, 1-ICON (CH3)2 (liquid range, -60,48°C to 149°C), two lactams, N-methylpyrrolidone monocarboxylic acid ester diside, ethyl acetate (liquid range,
-83,6~77,06℃) Orthoester: e.g., trimethyl orthoformate, HC(OCH3)3 (t
iJI point, 103°C) two lactones, γ-butyrolactone (liquid range, -42 to 206°C) dialkyl carbonate: e.g., dimethyl carbonate, QC(OCH3)2 (liquid range, 2 to 90°C) two alkylene carbonates, Two propylene carboxyethers, diethyl ether (liquid range, -116 to 34.5°C) Polyethers: Examples, 1,1- and 1,2-dimethoxyethane (liquid range, respectively -113,2 to 64.5°C) ℃
and -58-83°C) two cyclic ethers, tetrahydrofuran (liquid range, -
65-67℃): 1,3-dioxolane (liquid range, -
95-18℃) Nitroaromatic di-side, nitrobenzene (liquid range, 5.7-210.8℃) Aromatic carboxylic acid halide di-side, benzoyl chloride (
Liquid range, 0 to 197°C), benzoyl bromide (liquid range, -24 to 218°C) Aromatic sulfonic acid halide: e.g., benzenesulfonyl chloride (liquid range, 14.5 to 251°C) Aromatic phosphonic acid di Halides: e.g., benzenephosphonyl dichloride (boiling point, 258°C) Aromatic diophosphonic acid dihalide: e.g., benzene thiophosphonyl dichloride (boiling point, 124°C at 5°C) (melting point, 22°C) 3-methylsulfolane (@ point, -1°C) Alkyl sulfonic acid halides: e.g., methane sulfonyl chloride (boiling point, 161°C) Alkyl carboxylic acid halides: e.g., acepuruchloride (liquid range, -112 to 50.9°C), acetyl bromide (
Liquid T! 3-methyl-2-oxazolidone Melting point, 15.9°C) Dialkyl sulfamic acid halides: e.g., dimethyl sulfamyl chloride (boiling point, 16.80°C) Alkyl halosulfonates: e.g., ethyl chlorosulfonate (boiling point, 151°C) Unsaturated heterocyclic carboxylic acid halogen 2-furoyl chloride (liquid range, -2 to 173°C), 2 five-layer unsaturated heterocyclic compounds, 1-mebruvirol (point 8B, 114°C)
), 2,4-dimethylthiazole (boiling point, 144°C),
Furan (liquid range, -85.65 to 31.36°C), Nisder and/or two halides of dibasic carboxylic acids, ethyl oxalyl chloride (boiling point, 135°C), mixed alkylsulfonic acid halides/carboxylic acid halide
2 examples of 1 chloride, chlorosulfonylacetyl chloride (boiling point, 98°C at 10 m), 2 dialkyl sulfoxides, dimethyl sulfoxide (liquid range, 18.4~
189℃) dialkyl sulfate, dimethyl sulfate (liquid range, -31.75~188.5℃) dialkyl sulfide: e.g., dimethyl sulfide
(Boiling point, 12[)'C) Alkylene sulfide: e.g., ethylene glycol
Sulfide (liquid range, -11~173°C) Two halogenated alkanes, methylene chloride (liquid range, -
95 to 40°C>, L 3-dichloropropane (liquid range, -99.5 to 120.4°C) Among the above, preferred organic solvents include sulfolane, crotonyl-lyl, nitrobenzene, Te1herahydrofuran, and methyl. Substituted tetrahydrofuran, 1,3-dioxolane, 3-methyl-2-oxazolidone, propylene or ethylene carbonate,
Sulfolane, γ-butyrolactone, ethylene glycol sulfide, dimethyl sulfide, dimethyl
sulfoxide, and 1,1- and 1,2-dimethoxyethane, particularly preferred are propylene carbonate and 1,2-dimethoxyethane, and mixed solvents of sulfolane and 1,2-dimethoxyethane. This is because they are believed to be the most chemically inert towards battery components and have a wide liquid range, especially since they make the cathode material highly and efficiently available. be.

As the negative electrode of the non-aqueous secondary battery used in the present invention, (i
) light metals, (ii) alloys of light metals, (iit) conductive polymers, or (iv) composites of light metals or alloys of light metals and conductive polymers. Among these (
ii), (iii) and (iv) are preferred, and (iv) is particularly preferred.

Examples of (i) light metals used as the negative electrode of the non-aqueous secondary battery include lithium, alkali metals such as sodium and potassium, aluminum, etc., and (ii) alloys of light metals such as lithium- Examples include aluminum alloy, lithium-zinc alloy, lithium-tin alloy, and the like. Examples of the conductive polymer (iii) include polypyrrole and polypyrrole X1rJ forms, polydiophene and polythiophene derivatives, polyquinoline, polyacene, polyvaraphenylene and polyvaraphenylene derivatives, polyacetylene, and the like. Furthermore, (iv) composites of light metals or light metal alloys and conductive polymers include composites of aluminum and polyacetylene, polyvara phenylene or polyvara phenylene derivatives, lithium-aluminum alloys and polyacetylene, polyvara phenylene or Examples include composites made of polyvaraphenylene derivatives.

The term "composite" as used herein refers to a homogeneous mixture of a light metal or an alloy of light metals and a conductive polymer, a laminate, or a modified product in which a base component is modified with another component.

The oxidized polymer J3 and the conductive polymer used as the electrodes of the non-aqueous secondary battery of the present invention may include other suitable conductive materials such as carbon black, acetylene black, metal, etc., as is well known to those skilled in the art. Powder, metal fiber, carbon fiber H
You can also mix them together.

In addition, polyethylene, modified polyethylene, polypropylene, poly(tetrafluoroethylene), polyethylene
It may be reinforced with a thermoplastic resin such as a copyrene-dieneter polymer (EPDM) or sulfonated EPDM.

In the non-aqueous secondary battery of the present invention, the oxidized polymer of the positive electrode is doped with Dovan 1 to 1 to 1 N atom in the oxidized polymer, preferably from 0.2 to 15 [l] per N atom in the oxidized polymer. is 0.2 to 1.0 mol.

Dope (2) can be freely controlled by measuring the amount of electricity flowing during charging. The current value, voltage value, doping time, etc. during doping depend on the height density and area of the oxidized polymer used, the type of dopan 1 to 1, the type of electrolyte, and the required electrical conductivity of the oxidized polymer. C- Although it cannot be generally specified, in the current pulse method, C is a pulse height of 1 μΔ/cj12 to 100.
Δ/cIR2, during pulse l x10'm5ec ~1
0hrs, pulse 1114 is 1×1O-27FLSC
C~1hrte, preferably pulse height is 1TrL△/
α2~IA/α2, during pulse 1m3 (3(~10se
c, the pulse interval is 10 m5ec~I1in. On the other hand, in the voltage pulse method, the pulse height is ov ~
IOV, during pulse 1X10' old ec ~ 10hrS, pulse interval 1 x 1O-27FLSeC ~ 1 hlT
cb V), preferably pulse height OV~5V, pulse middle 1m5ec~10sec, pulse interval 10m
5ec ~i win.

In the current pulse method, the entire pulse process may be performed with a constant current, or the current may be varied within the range -F during the pulse process. Similarly, in the voltage pulse method, b
The entire pulsing process may be carried out at a constant rh pressure, or the voltage may be varied within the above range during the course of the pulsing. In addition, in the current pulse method and voltage pulse method, 1
Even if you change the pulse duration or pulse interval every time you complete a cycle, J: <, for example, 1 pulse every time you complete a cycle.
1] or the pulse interval may be gradually shortened.

In the present invention, polyethylene, bolyb[
There is no problem in using -C as a diaphragm using a porous membrane made of synthetic resin such as 1-pyrene or natural fiber paper.

In addition, some of the electrodes used in the non-aqueous secondary battery of the present invention may react with oxygen or water and deteriorate the performance of the battery, so the battery should be sealed and substantially oxygen-free. and preferably in an anhydrous state.

[Effects for light] The non-aqueous secondary battery that can be charged by the charging method of the present invention has high energy density, high charge/M electric power rate, long cycle life, low self-discharge rate, Good voltage flatness during discharge. In addition, the 11 water-conveying battery obtained by the charging method of the present invention is compact, compact, and has high energy density, so it can be used for portable devices, electric vehicles, gasoline automatic vehicles, and power storage. It is ideal as a battery for

[Example] Hereinafter, the brightness of the tree 5 will be explained in more detail by giving Example a3 and a comparative example. 'Example
1 [Production of oxidized polymer 1 Add distilled water, t-lBF4, and aniline to a glass container,
The concentration of HB F4 is 1.5E, and the concentration of aniline is 0.
The amount was adjusted to 7 mol. Water-soluble 82! Medium 1-2ct
Two platinum electrodes of 6 cm2 each were placed at a distance of n, and then electrolysis was carried out with an electric current of 120 amperes/sec while stirring. At this time, a black-purple oxidized polymer was deposited on the anode plate. The coated anode was repeatedly washed 3 times with distilled water, then 70
After vacuum drying at °C, the produced oxidized aniline polymer film was peeled off from the platinum plate.

[Production of film-like aretylene polymer] 1. '7 Irt1 ditanium detrabutoxy 4oid was added and dissolved in 30-anisole, and then 2. γml
A catalyst solution was prepared by adding ethylaluminum while stirring.

This reaction vessel was cooled with liquid nitrogen, and the nitrogen gas in the system was 4" (1 atmosphere with an empty pump).Then, this reaction vessel was cooled to -78℃!J1C, and the catalyst solution was kept still. MaJ,
So, purification a with a pressure of 1 atm? 1- Injected with brick gas.

Immediately, polymerization occurred on the surface of the catalyst solution, and an 11)-shaped aleprene high polymer was produced. Thirty minutes after the introduction of ahitylene, the aretylene gas in the reaction vessel system was exhausted to stop the polymerization. After the catalyst solution was removed in a Q4 vessel under a nitrogen atmosphere, it was washed 5 times with a 100 ml purification process while being kept at -78°C. The membrane-like acetylonone polymer swollen with toluene was a uniform membrane-like swollen product in which fibrils were tightly intertwined. Next, this swollen product was dried under vacuum V2 to obtain a reddish-purple film with a metallic luster, a thickness of 180 μm, and a 98% cis-3 content. :Nida, the height density of this membranous acebu-1 non-high polymer is 0.3
0 SF/CC, and its electrical conductivity (DC four-terminal method) was 3.2X 10'Q''·cm-1 at 20°C.

[Battery experiment] From the aniline oxidation composite film and the membranous acetylene polymer obtained by the above method, a diameter of 20 m was obtained, respectively.
A battery was constructed by cutting m disks into pieces and using them as active materials for a positive electrode and a negative electrode, respectively.

The figure is a schematic cross-sectional view of a battery cell for measuring the characteristics of a non-aqueous secondary battery, which is a specific example of the present invention. Platinum wire mesh current collector for negative electrode, 3 is a disc-shaped negative electrode with a diameter of 20 m, 4 is a diameter of 20#
A circular porous polypropylene diaphragm with a thickness that is sufficient to impregnate the electrolyte, 5 is a disk-shaped positive electrode with a diameter of about 20 mm, and 6 is a platinum wire mesh current collector for the positive electrode with a diameter of 20 mm and 80 mesh. , 7 is a positive electrode lead wire, and 8 is a screw-in container made of CFC.

First, the platinum wire mesh current collector 6 for the positive electrode is placed in a Teflon container 8.
The positive electrode 5 is roughly placed on the platinum wire mesh current collector 6 for the positive electrode, the porous polypropylene diaphragm 4 is placed on top of the positive electrode 5, and after sufficiently impregnated with the electrolyte, the negative electrode 3 is placed in the lower part of the recess. Overlap the
Further, a platinum wire mesh collection body 2 for negative electrode was placed on top of it, and a battery was produced by tightening the differential container 8.

``The electrolyte used was a 1 mol/fJ solution of LiBF4 dissolved in an equal volume of 1 of a mixed solvent of propylene carbonate and 1,2-dimethoxyethane, which had been distilled and dehydrated according to a conventional method.

Using the battery thus prepared, a constant current pulse method (pulse height 5.07 rLA/cm) was performed in an argon atmosphere.
2. Charge was performed by flowing an amount of electricity corresponding to a doping concentration of 40% and 6 mol% to the positive and negative electrodes, respectively, at a pulse interval of 25 (IC) for 1 sec during the pulse. Immediately after charging was completed, the battery was discharged under a constant current (2.5mA/C1n2), and when the battery voltage reached 0.5V, it was charged again under the same conditions as above.A repeated charge/discharge test was performed. The number of charging/discharging cycles recorded was 742 before the charging/discharging efficiency decreased to 10%.

In addition, the energy density per unit song of the active material after the fifth repetition was 161 W・br/Ng, which was the highest
The discharge efficiency t;L was 100%. Also, when left charged for 62 hours, its self-discharge rate was 1.3.
%Met.

Comparative Example 1 A [cell experiment] was carried out in exactly the same manner as in Example 1 except that the charging was carried out at a constant current of 2 mA/cm2, but the number of repetitions was 429 and the energy density was 1 unit. 1
59W-hr/K9, maximum charge/discharge efficiency of 98%,
The self-discharge rate was 51% C. Example 2 In Example 1, instead of the acetylene polymer used in the negative electrode, Plutin of the Chemical Society of Japan, Vol. 51 , p. 2091 (i978
I [) (Bull, Chcm, Soc, Japan
, 51° 2091 (i978)) at 1t00/cm
The negative electrode was formed into a 20 mφ disc shape at a pressure of 2, and the doping rate was 40%.
[Battery experiment] was carried out in exactly the same manner as in Example 1, and as a result, the number of repetitions until the charging/discharging efficiency decreased to 70% was recorded as 705 times. The theoretical energy density of this battery is 178W・hr/nibi, and the maximum charge/discharge efficiency is 1
(I was 0%. Also, when I left it charged for 62 hours, its self-discharge rate was 23%.

Example 3 Except for J3 in Example 1, a Li-to-ρ alloy (atomic ratio of 1:1) was used as the negative electrode instead of the acetylene polymer used for the negative electrode, and the utilization rate was reduced by 50%. (Battery experiment) was carried out in exactly the same manner as in Example 1. As a result,
Charge/discharge efficiency drops to 70%. -1: The number of repetitions was 818 times. The energy density of this battery is 241W・hr/Kg, and the maximum charge/discharge efficiency is 1
It was 00%. Furthermore, when the battery was left charged for 62 hours, its self-discharge rate was 0.9%.

Example 4 Polyparaphenylene 104 used as the negative electrode in Example 2
7 and li-AN metal-containing 10 used as the negative electrode in Example 3.
9 was pulverized and mixed, and then this mixture was mixed at 1 ton/C1
A composite was produced by pressure molding at a pressure of 2. This composite was used as the negative electrode and charged by constant voltage pulse method (pulse height 4V, pulse duration 1sec, pulse interval 2SaC).
[Battery experiment] was conducted in exactly the same manner as in Example 1.

As a result, the number of repetitions until the charging/discharging efficiency decreased to 70% was 901 times. The energy density of this battery was 215-hr/Kg, and the maximum charge/discharge efficiency was 100%. Furthermore, when the battery was left charged for 62 hours, its self-discharge rate was 0.8%.

Comparative Example 2 [Battery experiment] was conducted in exactly the same manner as in Example 4, except that charging was performed using a constant current method of 2 mΔ/α2, but the number of repetitions was 411 times, and the energy density was 209 cm.
hr/A9, the highest charge/discharge efficiency was 97%, and the self-release rate was 6.9%.

[Brief explanation of drawings]

The figure is a schematic cross-sectional view of a battery cell for measuring characteristics of a non-aqueous secondary battery, which is a specific example of the present invention. 1... Platinum lead wire for negative electrode 2... Platinum wire mesh current collector for negative electrode 3... Negative electrode 4... Porous polypropylene membrane 5... Positive electrode 6... Platinum wire mesh collection for positive electrode City body 7...Positive lead wire 8...Teflon container Patent applicant Showa Denko Co., Ltd. Hitachi, Ltd.

Claims (1)

[Claims] An oxidized polymer of aniline compound is used for the positive electrode, and (
In a method for charging a non-aqueous secondary battery using i) a light metal, (ii) an alloy of light metals, (iii) a conductive polymer, or (iv) a complex of a light metal or an alloy of light metals and a conductive polymer, the current A method for charging a non-aqueous secondary battery, characterized by charging by a pulse method or a voltage pulse method.