JPS6147713A - Polymeric compound and ionic conductive material - Google Patents

Abstract

PURPOSE:To provide the titled polymeric compound containing specific numbers of structural units represented by respective specific structural formula, having a specific molecular weight, exhibiting electrical conductivity caused solely by the transfer of cation, and having high conductivity and excellent film-forming property. CONSTITUTION:The objective polymeric compound having a molecular weight of 10,000-about 200,000 and containing 1-40mol% structural unit of formula IIIand 60-99mol% structural unit of formula IV can be prepared by mixing the electrolyte of formula I (R is H or CH3; M is H, Li, Na or K) and the macromer of formula II (R is H or CH3; R' is H, CH3, C2H5, acetyl or propionyl; n is 3-20) at a molar ratio of 1:99-40:60, optionally adding a polymerization initiator (e.g. azobisisobutyronitrile), and thermally polymerizing the mixture. USE:A solid electrolyte for various electronic parts, etc.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to polymer compounds and ionic conductors.
In particular, it relates to a polymer ion conductor with excellent film forming properties.

[Conventional technology and problems]

In general, polymer electrolyte type ionic conductors have been proposed with the aim of achieving good moldability while exhibiting ionic conductivity only for cations, and are now being applied to electronic components. . however,
Until now, very few polymer ion conductors have been developed that have achieved the above goals.

As this kind of polymer electrolyte type ionic conductor ~Solid State Ionics (5oldState)
Ionics), Vol. 2, p. 347 (1981), reports that a predetermined amount of lithium perchlorate is dispersed in high-molecular-weight j91J ethylene oxide, but these have poor flexibility and ion Conductivity is 10-10S/
It's stuck at cIIL. In addition, its conductivity is based on the migration of both cations and anions. Considering its application to electronics components, the movement of anions is
Leakage current is undesirable because it impairs the long-term stability of the electronics components.

Therefore, an object of the invention is to provide a polymer ion conductor whose conductivity is based on the movement of only cations, has good conductivity, and has excellent tumor resistance.

[Means for solving problems]

In order to achieve the above object, the present invention uses the formula (where,
R is hydrogen or a methyl group, and M is hydrogen, lithium,
a structural unit represented by sodium or potassium) and a formula (where R is hydrogen or a methyl group, R' is hydrogen, a methyl group, an ethyl group, an acetyl group, or a propionyl group, and n is from 3 to The present invention provides a polymer compound containing 60 to 99 molar structural units represented by (integer 201) and having a molecular weight of about 10,000 to about 200,000, and an ion conductor made of this polymer compound. be.

In the polymer compound constituting the ion conductor of the present invention, ethylene oxide, which forms part of the side chain of the structural unit of formula (If), has a very low glass transition point and is in the form of a pseudo solution in the polymer compound. Provides a field and forms an ion conduction path.

The value of n in formula (I[) is limited to 3 to 20 in order to form this pseudo-solution-like ion conduction path. If the value of n is less than 3, it is not possible to form a sufficient ion conduction path, while if the value of n exceeds 20, it is not possible to provide a solid-like field or a pseudo-solution-like field. .

The structural unit of formula (I) provides the cation (i.e., M ) that moves through the ion conduction path, and fixes the anion (carxyl anion) in its structure after the cation leaves, thereby preventing the movement of the anion. K so as not to cause
are doing. Thus, in the ionic conductor of the present invention, only cations migrate.

In addition, since the main chain of the polymer compound constituting the ion conductor of the present invention is formed by polymerization of vinyl groups, it has excellent film-forming properties and can be used as a compound represented by the above formula (I). The monomer inducing the structural unit may be an electrolyte monomer represented by the formula (where R and M are as defined in formula (I)), or an electrolyte monomer having the above formula (In
The monomer inducing the structural unit represented by is a (meth)acrylate having oligoethylene oxide in the side chain, represented by the formula (where R, R' and n are the same as defined in formula (II)). It is a macromer.

To produce the polymer compound of the present invention, the electrolyte of formula (4) and the macromer of formula (B) are heated and polymerized at a molar ratio of about 1:99 to 40:60. During the polymerization, a polymerization initiator such as azobisisobutytetranitrile (AIBN
) is preferably added to the macromer in an amount equivalent to, for example, 00 moles of IA. Polymerization temperature is 80℃~100℃
There is no particular restriction on the preferred monopolymerization method. for example,
A method of kneading the electrolyte monomer of the formula (B) and a macromer of the formula (B) and heating it in an inert atmosphere, a method of casting the kneaded product on a plate such as Teflon and heating it under reduced pressure, Alternatively, either of the two polymers may be dissolved in an organic solvent such as tetrahydrone (THF), degassed, and polymerized. In this way, a copolymer containing each structural unit in the same proportion as the charged molar ratio is produced.

In this copolymer, the molar ratio of each structural unit is important; as mentioned above, the structural unit of formula (I) has a molar ratio of 11 to 40, and the structural unit of formula (In) has a molar ratio of 99 to 40. 6
It is 0 moles. If the molar ratio deviates from this range, the desired ionic conductor cannot be obtained. Within this range, as the proportion of the structural unit (1) increases, the ionic conductivity tends to increase gradually. If the proportion of structural unit (1) exceeds 40 molti, a homopolymer of structural unit (1) and a monomer of formula (4) will be produced in addition to a copolymer with structural unit (II). , the resulting film becomes brittle. Moreover, if the proportion of the structural unit (1) is less than 1 molty, the ionic conductivity will be low.

The polymer compound forming the ion conductor of the present invention has a molecular weight of about 10,000 to 200,000, and within this range, it has excellent ion conductivity and film-forming properties.

In addition, although the film forming property is not significantly affected by the types of R and M in the structural unit (1), the mobility of M ions, which serve as dissociative energy carrier ions in the electrolyte, differs depending on the type. The ionic conductivity of the polymer compound varies accordingly.

Examples of the present invention will be described below, but prior to that,
An example of synthesis of an electrolyte of formula (A) and a macromer of formula (B) will be described.

Synthesis Example 1 20Ii of one-end methyl ether oligoethylene oxide (ethylene oxide unit: about 5 moles) having a molecular weight of 250 was dissolved in 200 m/ml of anhydrous THF, and 5Il of metallic lithium was added under boiling reflux. After 1 day of reaction, excess gold IA
I7thium was filtered out. While cooling the filtrate to 0°C, a solution of methacrylic acid chloride 1011 diluted with 501 nl of THF was added dropwise to 2Bv1. After that, the reaction was further continued for 5 hours at room temperature.

After concentrating the reaction mixture under reduced pressure to about 100-
The polybasic alumina potassium was removed with chloroform, and the desired macromer (in formula (B), R=methyl,
A chloroform solution of R1==methyl, n=5) was obtained.

As a result of fractionating and analyzing a part of it, the yield was approximately 22.9%. Nuclear magnetic resonance spectroscopy (in CDCl3, pp.
m) good, h: 2. 'O(3K),b,c
: 5.5 t 6.1 (2H), d : 4.2
(2H), e: 3.6 (18H).

Since f: 3.3 (3H) was observed, the structure was confirmed.

Synthesis Examples 2 to 5 As one-terminal methyl ether oligoethylene oxide,
The molecular weights are 350 (about 8 moles of ethylene oxide units) and 550 (about 13 moles of ethylene oxide units), respectively.
Mol: Synthesis Example 3), 750 (approximately 1 ethylene oxide unit)
The corresponding macromers were obtained in the same manner as in Synthesis Example 1, except that 7 moles of ethylene oxide units (Synthesis Example 4) or 900 (about 20 moles of ethylene oxide units) were used. The yields were 21 g, 20 g, 19 g, and 19 g, respectively (J), and the same nuclear magnetic resonance spectra as in Synthesis Example 1 were obtained except that the e7' roton ratio was different.

Synthesis Examples 6 to 10 Corresponding macromers were synthesized in the same manner as Synthesis Examples 1 to 5, except that acrylic acid chloride was used instead of methacrylic acid chloride. The yield is 21
grams (Synthesis Example 6: using one-end methyl ether oligoethylene oxide with a molecular weight of 250), 20 grams (Synthesis Example 7: using one-end methyl ether oligoethylene oxide with a molecular weight of 350), 19.5 grams (
Synthesis Example 8: Using methyl ether oligoethylene oxide at one end with a molecular weight of 5500), 19 grams (Synthesis Example 9: Using methyl ether oligoethylene oxide at one end with a molecular weight of 750) and 18.7 grams (Synthesis Example 10: Molecular weight 9000 one-end methyl ether oligoethylene oxide). Synthesis examples 1 to 5
Compared to the compound of formula (1), a similar nuclear magnetic resonance spectrum was obtained except that the a proton in formula (1) disappeared.

Synthesis Examples 11 to 13 In place of the one-terminal methyl ether oligoethylene oxy P, one-terminal ethyl oligoethylene oxide (Synthesis Example 11), one-terminal methyl ester oligoethylene oxide (Synthesis Example 12), and one-terminal ethyl ester each having a molecular weight of 400. Olyte ethylene oxide (Synthesis Example 13) A corresponding macromer was obtained in exactly the same manner as in Synthesis Example 1, except that oleite ethylene oxide was used. Yields were 25 grams, 19 grams and 21 grams, respectively.

The nuclear magnetic resonance spectra of each compound obtained are shown in Synthesis Example 1.
Synthesis Example 11 Synthesis Example 12 Synthesis Example 13 Synthesis Example 14 10 grams of methacrylic acid and 1 liter of lithium hydroxide gram in methanol at 25° C. for 2 hours. The reaction product was precipitated from the acetate and dried under reduced pressure at 40° C. for 17 hours to yield approximately 3 grams of lithium methacrylate as a white solid.

Synthesis Examples 15-16 2.5 grams of sodium methacrylate (Synthesis Example 15) and 2.5 g of sodium methacrylate (Synthesis Example 15) and 2.5 grams of potassium methacrylate (Synthesis Example 15) was obtained.

Synthesis Example 17 Methacrylic acid was purified by vacuum distillation before use and used in the following reaction.

Examples 1 to 11 Chloroform was distilled off from the macromer solutions obtained in Synthesis Examples 1 to 10, and methanol (MaOH) was added in the amount shown in Table 1.
) was added to make a methanol solution. Synthesis Examples 14 to 17 in which 1/100 molar amount of azobisisobutyronitrile was added to this methanol solution and the ratio shown in Table 1 was added to the macromer.
monomers were mixed. This mixture was spread on a Teflon plate, and after methanol was evaporated, silent direct polymerization was carried out at #100°C under reduced pressure for 24 hours.

Film thickness, molecular weight (
The obtained polymer compound was dissolved in water and dialyzed for 2 days to remove azobisisobutyronitrile as a polymerization initiator, resulting in a solution containing only the polymer compound, and measured using a light scattering method. In addition, since no monomer was observed in the dialysate, it is considered that all the monomers were polymerized. This fact was also observed in all other examples below. ), and ionic conductivity are also listed in Table 1. Note that the ionic conductivity is graphite/polymer compound membrane/
Create a battery composed of graphite and generate 100Hz
The values were obtained by measuring the current value when an alternating current voltage of ~100,000 Hz was applied and performing complex impedance plot processing.

Examples 12 to 16 Chloroform was distilled off from the macromer solutions obtained in Synthesis Examples 2, 6, 9, 11, or 12, and tetrahydrofuran solutions were prepared by adding tetrahydroalan (THF) in the amount shown in Table 2. Synthesis Examples 14 to 1 were added to this solution in the proportions shown in Table 2.
6 monomer and azobisinobutyronitrile (Human IB
N) was mixed and polymerized at 80° C. for 48 hours under degassing.

A small amount of this reaction product solution was spread on a Teflon plate, and after evaporating Teflon, it was left standing at 60° C. under reduced pressure for 24 hours to produce a thin film. This film thickness and Examples 1 to 11
The molecular weight and ionic conductivity measured in the same manner as above are also listed in Table 2.

Examples 17 to 27 The monomers of Synthesis Examples 14 to 17 were kneaded with the macromers obtained in Synthesis Examples 1 to 10 in the proportions shown in Table 3, and the mixture was cast onto a Teflon plate and then placed in an inert gas atmosphere. Polymerization was carried out for 5 hours at the temperatures shown in Table 3 to obtain a thin film of the polymer compound of the present invention.

The thickness of this thin film, as well as the molecular weight and ionic conductivity measured in the same manner as Examples 1 to 11 are also listed in Table 3.

The polymer compound of the present invention described above can be used as a solid electrolyte for solid electrolyte batteries, electrochromic displays, display devices, and the like.

FIG. 1 shows a lithium battery using an ionic conductor made of a polymer compound of the present invention (in formula (1), M is a group other than hydrogen) as a solid electrolyte. This battery 10 uses, for example, nickel metal foil (for example, diameter 101111% thickness 0.1 mg) as the negative electrode current collector 15.
A lithium metal layer 14 as a negative electrode active material is deposited on one side of the negative electrode current collector 15 to a thickness of, for example, 10 μm. The negative electrode active material 15 faces the positive electrode 12 on the lithium metal foil 14 side via a solid electrolyte 13 made of a thin film of the polymer compound of the present invention. The positive electrode 12 uses polytetrafluoroethylene as a binder, manganese dioxide as an active material, Cargo Brass as a positive electrode current collector,
For example, 10 m in diameter and 0.1 vg in thickness.
It is made to the size of. The solid electrolyte 13 is argon dry between the positive electrode and the negative electrode. , inserted in the box,
10 to 70 kits/art while maintaining reduced pressure between the two electrode plates
It is fixed by pressing under pressure of 2. This battery body is assembled into, for example, an inner can 1 made of stainless steel, and further covered with an outer can 16 made of stainless steel. The inner can 11, the outer can 16, and between the negative electrode and the positive electrode are made of an insulating material such as polytetrafluoroethylene/4. King 17 is inserted.

Figure 2 shows the polymer compound of this invention as a solid state electrode.

2 shows an electrochromic display device having as a solute. This display device 20 includes a transparent electrode substrate 2 made of Nesa glass, and a glass substrate 25 facing and disposed apart from the electrode 21. On the transparent electrode of the transparent electrode substrate 21, for example, tungsten trioxide or molybdenum trioxide as the electrochromic material 22 is
It is deposited to a thickness of μm. Further, on the side of the glass substrate 25 facing the transparent electrode substrate 21, an electrode 24 made of a vapor-deposited film of gold or silver (thickness, for example, 5 μm) is formed. A solid electrolyte 23 made of the polymer compound of the present invention is formed between the transparent electrode substrate 21 and the electrode 24 in close contact with each other under pressure. There are no particular limitations on the polymer compound of the present invention used in this case. Lead wires 27 and 28 are connected to the transparent electrode substrate 21 and the positive electrode 24, respectively.

Example A The thin film of the polymer compound obtained in Examples 1, 2, 12, 14, 17 and 22 was used as the solid electrolyte 13 of the lithium battery shown in FIG. 1, and the battery performance was measured. Voltage 3.1 telt, initial closed circuit current density 150μAA
IIL 2, and average open circuit voltage 3.0 quilts.

Example B Under the conditions shown in Table 4 below, an electronic display device as shown in FIG. Color developed at the response speed shown in . This display color quickly disappeared by applying a voltage of opposite polarity.

Example C Using the polymer compound of the present invention obtained in Example 1, a battery having a configuration of lithium/polymer compound/lithium was formed, and the conductivity of the polymer compound was measured over time when a DC voltage of 3R was applied. was measured. The results are shown in Figure 3 by line a. For comparison, lithium perchlorate or lithium l-butyrate was added to a homopolymer having a structure of the formula (In) at 10%
Those of the composite membrane blended in the ratio of molch are shown by lines and C, respectively. As can be seen from this figure, the stability of the ionic conductivity of the polymer compound of the present invention over time is far superior to that of the comparative example. In addition, the convergence value of the ionic conductivity of the polymer compound of the present invention is equal to or higher than the initial value of 2A, and the polymer compound of the present invention has a structure of the formula ([) with lithium l-butyrate, which is similar in shape to lithium methacrylate. Since the convergence value of ionic conductivity is higher than the conductivity of the composite membrane with the polymer (line C), the ionic conductivity of the polymer compound of this invention is based on the movement of only cations. It is shown.

-1 [Effects of the Invention] As described above, the polymer compound of the present invention has good ionic conductivity and excellent film forming properties. Therefore, the polymer compound of the present invention is useful as a solid electrolyte for various electronic components.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of a lithium battery incorporating the polymer compound of the present invention as a solid electrolyte. FIG. 2 is a schematic cross-section of an electrochromic display device incorporating the polymer compound of the present invention as a solid electrolyte. 3 are graphs showing changes over time in the ionic conductivity of the polymer compound of the present invention together with comparative examples. 13.23...Solid electrolyte applicant's representative Patent attorney Takehiko Suzue Figure 1 Figure 2 Figure 3 Figure 4 Akira (Bo) Procedural amendments Commissioner of the Patent Office Manabu Shiga 1, Indication of the case Patent application Akira 59-168820 No. 2, Name of the invention: Polymer compound and ionic conductor 3, Relationship with the person making the amendment Patent applicant: 1) Shun Hide 4, Agent address: 1-26-5 Toranomon, Minato-ku, Tokyo No. 17 Mori Building 7, Contents of amendment (1) From page 8, line 19- to page 9, line 1 of the specification, “because the life of the electrolyte is different” has been changed to “the dissociation energy of the electrolyte and the carrier ion This is because the mobility of M ions differs depending on the type of M ions.'' [2] Replace "Teflon" on page 8, line 10 of the specification with rT.
Corrected to HFJ. (3) On page 21, item 12 of the specification, between “as an electrolyte” and “use”, “or as a non-chargeable material”
Insert. (4) “Negative electrode active material” on page 21, line 12 of the specification
is corrected to "negative electrode current collector". (5) "Shape" on page 21, No. 12 of the specification is "structure"
I am corrected.

Claims (2)

[Claims] (1) Formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (Here, R is hydrogen or a methyl group, and M is hydrogen,
1 to 40 mol% of structural units represented by lithium, sodium or potassium) and formulas ▲mathematical formulas, chemical formulas, tables, etc.▼ (where R is hydrogen or methyl group, R' is hydrogen, methyl group, ethyl group) , an acetyl group or a propionyl group, and n is an integer from 3 to 20).
0 to 99 mol%, and has a molecular weight of about 10,000 to about 200,000. (2) Formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (Here, R is hydrogen or a methyl group, and M is hydrogen,
1 to 40 mol% of structural units represented by lithium, sodium or potassium) and formulas ▲mathematical formulas, chemical formulas, tables, etc.▼ (where R is hydrogen or methyl group, R' is hydrogen, methyl group, ethyl group) , an acetyl group or a propionyl group, and n is an integer from 3 to 20).
0 to 99 mol%, and has a molecular weight of about 10,000 to about 200,000.