JPH02252762A - Solid polyelectrolyte - Google Patents

Abstract

PURPOSE:To obtain a solid polyelectrolyte having a high ionic conductivity at a temp. lower than room temp. and excellent film-forming properties by compounding a polymer having a main chain comprising polyphosphazene and side chains contg. ethylene oxide groups and a salt of a specific metal ion. CONSTITUTION:At least a polymer contg. repeating units of formula I (wherein L1 and L2 are each a divalent linkage; X1 and X2 are each a trivalent linkage; R1 and R2 are each H or a lower alkyl; R3 and R4 are each H, an alkyl alkenyl, aryl, or aralkyl; and n is 1-30) (e.g. a polymer contg. repeating units of formulas II and III) and a salt of a metal ion of the group Ia or IIa (e.g. LiCF3SO3, NaClO4, or KSCN) are compounded to give a solid polyelectrolyte, which shows a high ionic conductivity at a temp. lower than room temp. and excellent film- forming properties and is suitably used as an antistatic material and as a material for a battery and other electrochemically devices.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a solid polymer electrolyte, which is suitable as an antistatic material and a material for batteries and other electrochemical devices.

[Conventional technology]

In order to apply solid electrolytes to antistatic materials and battery chemical devices, they must not only have good ionic conductivity, but also have excellent film formability, good storage stability, and materials. It is also necessary that it be easy to manufacture. However, no solid electrolyte that comprehensively satisfies these required performances has been developed to date.

For example, Na-β-An! gos or Na+-x ZrzP2-1ISixO+g (0≦X
It is known that inorganic solid electrolytes such as
of Chemical Physics) Volume 54 4
14 pages (1971), A. Clearfield (A.
C1earfield et al. Solid State Ionics9
/10S, p. 895 (1983) has a fatal drawback of extremely low mechanical strength and poor processability into visible films.

Polyethylene oxide (hereinafter abbreviated as PEO) is a salt of various metal ions belonging to Group Ia or Group IIa of the periodic table.
For example LiCFsSOs, LiI, 1.1cj2
It forms a complex that functions as a solid electrolyte with 0s, Nal, NaCPISOs, KCF, So, etc., and exhibits relatively good ion conductivity.・In Solid (Past Ton
Transport in 5 Solids, p. 131 (1979)), and has the viscoelasticity and flexibility characteristic of polymers, and has good processability and storage stability.

However, the ionic conductivity of PEO is highly temperature dependent, and although it shows good ionic conductivity above 60°C,
At temperatures below 0°C, the ionic conductivity deteriorates significantly, making it difficult to incorporate it into versatile products that can be used in a wide temperature range. As a method to overcome the problem that the ionic conductivity of the PEO-based solid electrolyte deteriorates significantly at temperatures below 20°C, Japanese Patent Laid-Open No. 62-1
No. 39266 has a molecular weight of 1. 0
A method of using a mixture of PEO having a low molecular weight of 0.00 or less has been proposed. However, this method has not yet proposed an essential solution to the conventional problem.In other words, if a large amount of low molecular weight PEO is mixed, the ionic conductivity around 20°C will improve, but the film forming property will be reduced. The decrease was significant, making it difficult to form a film. As a method for improving ionic conductivity using low molecular weight PEO, D.J. Bannister (D, J.
, Ban1ster et al.
me r ), vol. 25, p. 1600 (1984),
In addition, a method for introducing low molecular weight PEO into the side chain of polyphosphazene was developed by D.F. Schereiver (D, F, 5hr
Journal of the American
Chemical Mesaetei (Journal of Am)
ericanChee+1cal 5ociety)
, Vol. 106, p. 6854 (1984), and in JP-A No. 63-241066, a material with an organic group having an amino group in the side chain of polyphosphazene is published, which also has an amide bond in the side chain of polyphosphazene. A material having an organic group containing is reported in JP-A-63-186766.

However, although such polymeric materials form complexes with Li salts and have good film-forming properties, they have insufficient ionic conductivity at temperatures below 20"C.

As mentioned above, it is possible to both solve and satisfy the two problems that conventional solid electrolytes made of PEO-based compounds and alkali metal salts have: extremely low ionic conductivity below room temperature, or extremely poor film-forming properties. However, there was a desire to provide a solid electrolyte that solved both problems.

[Purpose of the invention]

An object of the present invention is to provide a novel solid electrolyte that exhibits high ionic conductivity below room temperature and has excellent film-forming properties.

[Means to solve the problem]

The above object is achieved by a polymer solid electrolyte characterized by containing at least a polymer compound containing a repeating unit represented by the following formula (I) and a salt of a metal ion belonging to group Ia or na of the periodic table. It was done.

General formula (1) R L+ X+-←0CHzCH-+-r-ORsg (wherein, L+ and Lx represent a divalent linking group,
χ represents a trivalent linking group, R,,R.

represents a hydrogen atom or a lower alkyl group, R1 and R4 represent a hydrogen atom, an alkyl group, an alkenyl group, an aryl group or an aralkyl group, and n is an integer of 1 to 30. ) Since the polymeric material of the present invention has an ethylene oxide group in its side chain, it has a high dielectric constant and is excellent in the ability to dissolve and dissociate a supporting electrolyte. In addition, since the main chain is made of polyphosphazene, the glass transition point (Tg) is low.
It is thought that this facilitates the movement of ions.

In particular, the polymer electrolyte of the present invention has a main chain composed of polyphosphazene and has two or more alkylene oxide groups per side chain. Surprisingly, the ionic conductivity near room temperature was significantly improved compared to the polymer electrolyte having alkylene oxide groups.

The present invention has made it possible to achieve both high ionic conductivity at low temperatures and good film formability, which could not be achieved with conventional polymer electrolytes.

Below - Equation [1] will be explained in detail.

L and R8 may be the same or different, and each represents a divalent linking group, and -0--5--N- and an alkylene group which may have a substituent are preferable examples of the substituent. can include a hydroxyl group, an alkoxy group, an alkyl group, and a halogen atom (chlorine atom, fluorine atom, etc.).

R represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms,
The divalent linking groups represented by L+ and L* are particularly preferably -0-, X and X2 are trivalent linking groups,
They may be the same or different. A preferred linking group for X and L!, L, and , which may be the same or different, represent divalent linking groups, and are preferably alkylene groups, arylene groups, and aralkylene groups.

QSrs 3% L is each independently 0 or 1.

) As specific examples of X and Xi, these groups preferably have 1 to 12 carbon atoms, and these groups may be substituted. Examples of substituents include: Examples include the substituents listed as substituents for alkylene groups.

R1 and R2 are preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and may be the same or different.
More preferably, 3 is a hydrogen atom or a methyl group.

R1 and R4 represent a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an alkenyl group, an aryl group, an aralkyl group,
R1 and R4, which may be the same or different, are preferably alkyl groups having 1 to 6 carbon atoms and which may have a substituent. Examples of the substituent include the substituents listed as substituents for the alkylene group of Ll.

n is an integer of 1 to 30, preferably 2 to 10.

The polymer compound of the present invention may have a plurality of repeating units of general formula (1).

The remaining repeating units in the polymer compound of the present invention include, for example, the following formula (III) or formula (IV).
) can be mentioned.

General formula (Ill) −←P−N→− R.

LI R& General formula (IV) L, -Rei-←P-N→- Lnee R1 (In the formula, R, and R? may be the same or different, and each is an alkyl group that may have a substituent. R.

or −+C1, C11-07I” irz, n
' is synonymous with n e L+ , Lx , L , R+
, Rs n have the same meanings as in general formula (1).

) The repeating unit represented by general formula (I) is 5 in the polymer.
The content is preferably 0 mol% or more, more preferably 80 mol% or more, and particularly preferably 100 mol%.

Representative examples of the repeating unit represented by the general formula (1) and copolymerization examples containing the repeating unit represented by the general formula (I) and the repeating unit represented by the general formula (II) or (III) are shown below. The theory is not limited to these.

Compound Example 1 (P-1) Compound 4 (P-4) 10P=N+ Compound Example 2 (P-2) Compound Example 5 (P-5) 10P=N+- 娨Compound Example 3 (P-3) Compound 6 (P CH3 Compound Example 7 (P shiυυ1-shiH 1; H 0-sy(IIs Compound Example 1
1 (P-11) Compound Example 12 (P-12) Compound Example 13 (P-13) \C1h(1+cHtcH* O÷rCH3 Compound Example Day (P-8) Compound Example 9 (P-9) Compound Example 10 ( P-10) Compound Example 14 (P-14) O→CHsCHt O÷r CHs The weight average molecular weight Mw (polystyrene equivalent) of the polymer compound of the present invention is preferably 2000 to 5,000,000, more preferably 10 .000 to 2,000,000.

The metal ions belonging to Group Ia or Group IIa of the periodic table used in the present invention are preferably lithium, sodium, or potassium ions, and representative metal ion salts include t, 1cpssos, LiPF*, LiCj! n
, Lil, LiBFn, LiCFsCOt, L
ISCN, Nal.

NaCFsSOs, NaClOs, NaBF, ,
HaASF&, KCFiSO3, KSCN, KPPi
, C1)4, KAsF4, etc.

More preferred is the above Li salt. These may be used alone or in combination of two or more, or may be used in combination with other electrolytes such as NBuJF4.

The ratio of the polymer compound of the present invention to the metal ion salt is preferably such that polyethylene oxide units are contained in a ratio of 2 to 50 times that of the metal ion salt.

More preferably, it is 6 to 30 times. If the ratio is too high, the Tg will increase and the ionic conductivity will decrease; if the ratio is too low, the effective ion concentration will decrease and the ionic conductivity will also decrease.

The polymer electrolyte of the present invention may further contain a polymer compound, another amphipathic compound, and the like.

Typical examples of the polymer compound that may be added are shown below, but the present invention is not limited thereto, and compounds that are compatible with the polymer compound of the present invention can be preferably used. .

Compound example (C-1) -(-CHz-CH→1- OCOCHs Compound example (C-2) +CH, -CH→]- Compound example (C-3) +CHt-CH! −0÷“ Compound example (C-4) +CH1-CH2-〇+- CH.

Compound example (C-5) CM.

1÷-CHg Ch- COO'CHz Further, as the amphipathic compound that can be added, any known amphipathic compound can be added.

Typical examples include those shown below, but of course they are not limited to these.

Compound example (C-6) CI&H3゜to+CI(z(jlto→Tcho CH.

Compound example (C-7) C+zH+sO+CHgCIh0 +rrC+tH+s
Compound Example (C-8) Typical examples of solvents for dissolving the polymer compound of the present invention and metal ion salts include: nitrile M such as acetonitrile and benzonitrile; carbonates such as propylene carbonate and ethylene carbonate; tetrahydrofuran; 3-
Ethers such as methyl-tetrahydrofuran, 2-methyl-tetrahydrofuran, tetrahydropyran, 1.3-dioxane, 1.4-dioxolane, 1.2-dimethoxyethane; Lactones such as T-butyrolactone and δ-butyrolactone; dimethyl sulfoxide; , tetramethylene sulfon, dimethylformamide, etc., but are not necessarily limited to these. These solvents may be used alone or in combination of two or more.

The polymer solid electrolyte of the present invention can be used as an antistatic material for plastic materials, as a battery, and as an electrochromic display device.
It can also be used as a material for various electrochemical devices such as capacitors.

Typical synthesis examples of the present invention are shown below.

Synthesis Examples Compound Example 1 Synthesis of a compound (P-l) containing 100% of the repeating unit represented by (P-1) (1) Synthesis of polydichlorophosphazene (D-1) (NPCj!z)i 100 g (0.29 mol)
into a Pyrex tube, and vacuum the inside of the tube (1
After the tube was sealed, the tube was placed in an open oven at 250° C. and reacted for 12,020 hours. After the reaction, the contents were taken out and sublimated (50゛C124
The target product was obtained by removing unreacted raw materials.

Yield 185g (yield 85%) The chemical structure was confirmed by 3IP-NMR two-element analysis.

Synthesis of (D-2) 23.0 g (0,247 mol) of epichlorohydrin
300 g of diethylene glycol monomethyl ether
(2,5 mol) and 60% oily sodium hydride 12
g (0.3 mol) was added dropwise at 60°C over 15 minutes. The ether layer was washed with water and dried over magnesium sulfate, and then the ether was distilled off to obtain a brown solution. The target product was obtained by vacuum distillation (171-182°C/2kg Hg). Yield: 44.5 g (60% yield) The chemical structure was confirmed by NMR, IR, elemental analysis, and GC.

(3) Synthesis of P-1 Polymer 230 g (0.101 mol) of Compound D-1 was dissolved in 200 ml of tetrahydrofuran, and 28 g (0.70 mol) of 60% sodium hydride was added thereto. To this solution, polydichlorophosphazene 4 was added under stirring at room temperature.
g (0,035 mol) of tetrahydrofuran 500
d was added dropwise over 3 hours. To this was added 0.1 g of n-tetrabutylammonium bromide, and the mixture was allowed to react at room temperature for 24 hours, and heated under reflux for an additional 2 hours. After the reaction, the system was neutralized with dilute hydrochloric acid and dialyzed against distilled water (72 hours). ).

The obtained polymer was dissolved in 400ml of acetone, and 52ml of hexane was added to reprecipitate it. This operation was repeated twice to obtain a yellowish white viscous solid. Yield 5.5g (yield 28%) Mw=800,000 Chemical structure is "P-NMR, 'H-NMR, IR.

Confirmed by elemental analysis.

〔Example〕

Hereinafter, it will be explained in detail using examples.

Example I P-1 polymer and LiChSOs were dissolved in THF at room temperature so as to have the composition ratio shown in Table 1. At this time P-1
The concentration of polymer was 3 wt%.

Then, cast this solution on a Teflon plate,
The solvent was treated under vacuum (10-'' to 1 O-'torr) at room temperature for 24 hours and at 60 °C for 24 hours to completely remove the solvent and obtain a uniform thin film.(■■O) Furthermore, P -1 polymer is replaced by P-2 polymer LiCFsSOs is replaced by LiCIO, but the Fit is the same.
A membrane was obtained. (OO[F]) For comparison, the thin film ΦOθ is the same as Example 1 except that the P-1 polymer in (■) was replaced with the following compound (E-1) described in JP-A No. 62-47713. It was created.

(E −1) ” PEO (Mw=600,000)
/” PEO (Mw=600)・2/1 mixture
1 Nippon Oil & Fats type and the Journal of American Chemical Society (instead of ■ P-1 polymer)
Journal of American Chemi
cal 5ociety) Volume 106, Page 6854 (1
A thin film was obtained which was the same as (1) except that the following compound (E-2) described in 1984) was substituted. (@Φθ
) (E-2) OCHzCllz OCHICHIOCH3-+ P
= N -3-Mkanaka10'OCHzC)It O
CHiCHi OCH3 For the thin film thus obtained, a sample consisting of stainless steel/thin film/stainless steel was created, and the impedance was measured at 0.1 Hz to 100,000 Hz (
The measurement temperature was 25°C), and the ionic conductivity was determined from the Cole-Cole port.

Further, film formability was determined by the following method. A thin film was formed on a glass plate by a casting method, and a scratch resistance test was conducted using a sapphire needle with a diameter of 1 m.The load applied to the needle when the film was destroyed and a scar remained was determined as the scratch strength.

The above evaluation results are shown in Table 1.

As can be seen from Table 1, it is clear that Examples @ to [F] of the present invention have better ionic conductivity and film formability near room temperature than Comparative Examples Φ to θ, and Comparative Examples O~θ
It is clear that the ionic conductivity near room temperature is better than that of .

〔Effect of the invention〕

According to the present invention, it is possible to obtain a polymer solid electrolyte that has excellent ionic conductivity at room temperature or lower and also has good film formability.

Patent Applicant: Fuji Photo Film Co., Ltd. 1, Incident Representation 2. Name of the invention 3. Person who makes corrections Relationship with the incident 1999 Patent Application No. 70 Coco Polymer solid electrolyte

Claims (1)

[Scope of Claims] A solid polymer electrolyte characterized by containing at least a polymer compound containing a repeating unit represented by the following general formula (I) and a salt of a metal ion belonging to Group Ia or IIa of the Periodic Table. . General formula (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, L_1 and L_2 represent divalent linking groups,
1 and X_2 represent a trivalent linking group. R_1, R_2 represent a hydrogen atom or a lower alkyl group, R_3, R_4
represents a hydrogen atom, an alkyl group, an alkenyl group, an aryl group or an aralkyl group. n is an integer from 1 to 30. )