JP3348810B2 - Ion conductive polymer electrolyte, method for producing the same, and capacitor using the same - Google Patents

Abstract

PURPOSE: To provide an ionically conductive polymeric electrolyte having sufficient ionically conductivity and having very high physical and chemical stability. CONSTITUTION: This ionically conductive polymeric electrolyte consists of a polymer containing as a polymerization component at least one kind of monomer selected from a group consisting of hydroxyalkyl acrylate, hydroxyalkyl methacrylate and vinylene carbonate, and contains at least an electrolytic salt. As the polymer, a homopolymer of a monomer, or a copolymer of a monomer and an electrolytic salt having a polymerizable double bond in a molecule, is used. A highly reliable electrolytic condenser and an electric double layer condenser can be obtained by using this ionically conductive polymeric electrolyte.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ion conductive polymer electrolyte, a method for producing the same, and an electrolytic capacitor and an electric double layer capacitor using the ion conductive polymer electrolyte.

[0002]

2. Description of the Related Art Conventionally, an electrolyte for driving an electrolytic capacitor has been used in which an ammonium salt is dissolved as a main solute in an organic solvent such as ethylene glycol. However, it has been difficult to obtain long-term reliability of a capacitor using such a liquid electrolyte due to leakage or evaporation of the electrolyte. Therefore, instead of the conventional liquid electrolyte, a device made of a polymer made of a mixture of a siloxane-alkylene oxide copolymer and polyethylene oxide is used as a base material, and an ion conductive polymer electrolyte in which an alkali metal salt is dissolved is used. Solidified,
There has been proposed an electrolytic capacitor that does not cause leakage or evaporation of the electrolytic solution.

In an electrolytic capacitor using an ion-conductive polymer electrolyte having the above-mentioned alkali metal as mobile ions, an alkali metal ion diffuses into a dielectric which is a constituent material of the electrolytic capacitor. Decreases,
Eventually, there was a problem of an electrical short circuit.
In order to solve such a problem, it is conceivable to use non-metal ions such as ammonium ions as mobile ions of the electrolyte constituting the electrolytic capacitor. However, in general, an ion conductive polymer electrolyte in which an ammonium salt is dissolved has a disadvantage that the ion conductivity is extremely low. Further, various polymer electrolytes proposed so far have a problem that when the temperature is lowered from room temperature to 0 ° C. or lower, the ionic conductivity is extremely lowered.

When an electrolytic capacitor is constructed by using such a polymer electrolyte having a low ionic conductivity for driving, the impedance of the element becomes large, and the usable applications are extremely limited due to power loss and heat generation during energization. So
It has not yet been put to practical use. When using an ion-conductive polymer electrolyte for driving an electrolytic capacitor, it is extremely important to achieve a high ion conductivity by combining a polymer matrix and an electrolyte salt. Has not yet been disclosed. In recent years, the use of aluminum electrolytic capacitors has been greatly expanded, and accordingly, long-term reliability during high-temperature storage has been emphasized. For example, there is a situation where quality assurance for a shelf life of as long as 10,000 hours at 105 ° C. is required. When the polymer electrolyte is placed in such a high-temperature atmosphere, physical or chemical deterioration such as cracking, shrinkage, and dissolution occurs, and the element characteristics are greatly impaired. There has not yet been proposed a solid electrolyte that does not cause performance degradation even in such severe environmental tests.

In recent years, electric double layer capacitors comprising sulfuric acid or an organic electrolyte as an electrolyte have been used for various electronic devices. The electric double layer capacitor using the sulfuric acid electrolyte has a problem that the withstand voltage per unit cell can be obtained only about 1.2 V which is equal to or lower than the electrolysis voltage of water, but the electric conductivity of the electrolyte is zero. It is extremely high at 0.7 S / cm, and is used as an application that requires a relatively large output current by utilizing this characteristic, for example, as a power supply for driving a device when the power is cut off (NEC Technical Report, Vol. 44, No. 10). No. 19
(1991) On the other hand, an electric double layer capacitor using an organic electrolytic solution, for example, an electrolytic solution using propylene carbonate as a solvent and tetraethylammonium perchlorate as a solute, is 2.4.
It has twice the withstand voltage as compared with capacitors using V and the above-mentioned sulfuric acid electrolyte. However, the conductivity of this electrolyte is 0.0
1 S / cm, about two orders of magnitude lower than sulfuric acid. Utilizing such characteristics, it is used, for example, for memory backup of small electronic devices (Carbon, No. 132, p. 57, 1988).

However, there is a possibility that a capacitor formed by using these liquid electrolytes leaks. Therefore, a capacitor using a polymer solid electrolyte has been proposed as a device which does not leak substantially. For example, an electrolyte is prepared by using polyvinyl alcohol containing a lithium salt such as lithium perchlorate as an electrolyte and impregnating the resultant with porous carbon to form an electrode (J. Power Sources, 3).
6, P87, 1991), and an example in which a crosslinked polyethylene oxide containing an alkali metal salt such as lithium perchlorate is used as an electrolyte, and this is mixed with activated carbon to form an electrode (JP-A-2-39513). No.)
It is. As described above, at present, as a configuration of a polymer solid electrolyte having a relatively high conductivity, a configuration in which a base polymer contains a lithium salt such as lithium perchlorate has been proposed. However, when an electrolyte is formed by using an alkali metal salt such as lithium perchlorate as a constituent material when forming the element, it is necessary to completely remove water from other constituent materials used at the same time. In particular, it is very difficult to completely remove water from porous carbon as an electrode material and to construct an element in that state, and therefore, practical use has not yet been achieved.

[0007] At present, a thin element is generally sealed with an electric insulating sheet such as polypropylene coated on the inner surface of a metal foil such as aluminum. According to the confirmation by the present inventors, when a device using the above-described electrolyte made of a lithium salt is sealed in such a form, for example, when the device is left in an atmosphere of 60 ° C. and 90% humidity, about 2% is obtained. Performance degradation of the element starts in a month. This is thought to be due to the moisture that gradually entered the interior from the sealant.
As a means for solving such a problem, it is conceivable to use the same ammonium salt as that used in the above-mentioned organic electrolyte as a salt constituting the solid polymer electrolyte. However, in general, it is difficult to dissolve a large amount of ammonium salt in the above-mentioned polymer compound such as polyvinyl alcohol and polyethylene oxide, and as a result, the ionic conductivity of the polymer electrolyte composed of ammonium and polyethylene oxide is extremely high. (Lower conductive polymer by Naoya Ogata Kodansha Scientific 199
0 years).

[0008] The ionic conductivity of the electrolyte constituting the capacitor acts as an electric resistance as a capacitor. If the ionic conductivity of the electrolyte is too small, only a weak output current can be obtained, and it is difficult to use the capacitor in practical use. It is.
More importantly, the capacity of the electric double layer capacitor is
Since it is proportional to the ion concentration in the electrolyte, there has been a problem that the capacity of the electric double layer capacitor made of the electrolyte composed of a small amount of ammonium salt as described above does not increase. In addition, the electrolyte salt used in the electric double layer capacitor needs to enter micropores of about several tens of angstroms existing in porous carbon such as activated carbon as an electrode material, and unless the molecule has an ion radius as small as possible. No. However, it is well known that the smaller the salt of an anion and a cation, the more difficult it is to dissolve in the base polymer (Basic Electrochemical Measurement, edited by The Electrochemical Society, P30, 1981).

As described above, when a polymer electrolyte made of a lithium salt is used as a constituent material, a complicated water removing step in the manufacturing process and a sealing agent that does not transmit moisture even in a high-temperature and high-humidity atmosphere are required. As a measure to solve such a problem, when a polymer electrolyte using an ammonium salt is used as an electrolyte for a capacitor, a large amount of a salt having a small cation / anion can be produced by a combination of a polymer base material and an ammonium salt. It is an extremely important requirement to realize a material having high ionic conductivity by dissolving in the material, but no specific configuration has been proposed which satisfies all the above-mentioned demands.

[0010]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an ion-conductive polymer electrolyte having sufficient ionic conductivity and extremely high physical and chemical stability. And Another object of the present invention is to provide an aluminum electrolytic capacitor having the same electrical characteristics as those using a liquid electrolyte and having extremely high reliability that could not be realized with a conventional electrolyte. .
Still another object of the present invention is to provide a highly reliable electric double layer capacitor having the same electrical characteristics as those using a liquid electrolyte.

[0011]

SUMMARY OF THE INVENTION The present invention provides a hydroxyalkyl acrylate, a hydroxyalkyl methacrylate and the like.
At least selected from good beauty group consisting of vinylene carbonate 1
With a kind of monomer and a polymerizable double bond in the molecule
To provide an ion conductive polymer electrolyte comprising a copolymer of the first electrolyte salt. Wherein the alkyl group of the hydroxyalkyl acrylates and hydroxyalkyl methacrylates, which can be used those having 1 to 5 carbon atoms, 2 carbon atoms
Or three are preferred. Among them also it is preferably of 2 carbon atoms.

[0012] <br/> polymer constituting the ionic conductive polymer electrolyte includes, among homopolymer of the monomer, the onset
In the bright, Ru using the copolymer of the first electrolyte salt having a polymerizable double bond in the monomer and molecules. The second component contained in the ion-conductive polymer electrolyte of the present invention .
The electrolyte salt of a carboxylic acid ammonium salt, a dicarboxylic acid salt, a dicarboxylic acid morpholinium salt, those selected from the group consisting of carboxylic acid quaternary ammonium salts and dicarboxylic acid quaternary ammonium salt. The second electrolyte salt is a second electrolyte salt that constitutes the copolymer .
1 of electrolyte may be the same as the salt.

A first compound having a polymerizable double bond in the molecule ;
As an electrolyte salt of the above, maleate or fumarate is preferably used. The copolymerization molar ratio of the copolymer ( first electrolyte salt / monomer) is 0.1 or more;
In addition, the average molecular weight of the copolymer is preferably 1,000 or more and one million or less. In the ion conductive polymer electrolyte to the previous SL copolymer matrix, further, as a second <br/> electrolyte salt, hydrogen maleate quaternary ammonium, hydrogen maleate N, N - dimethyl morpholinium , ammonium hydrogen fumarate quaternary and hydrogen fumarate N, N - at least <br/> selected from the group consisting of dimethyl morpholinium preferably contains one salt.

[0014] The present invention is also the first electrolyte salt having the hydroxyalkyl acrylates, the polymerizable double bonds in the molecule at least one monomer selected from the group consisting of hydroxyalkyl methacrylate and vinylene carbonate And a method of irradiating the solution obtained above with actinic rays or applying heat to cure the solution. Since the first electrolyte salt is a compound having a polymerizable double bond in a molecule, such as a maleate or a fumarate , the actinic ray or heat causes
The first electrolyte salt forms a copolymer with the monomer and cures. Incidentally, the electrolyte salt, when a compound having no polymerizable double bond in a molecule, by the active light or heat, the monomer is cured to form a homopolymer.

The present invention further provides a capacitor provided with the above-mentioned ion-conductive polymer electrolyte. That is, an electrolytic capacitor comprising an anode made of aluminum, an anode having a dielectric layer made of aluminum oxide, and an ion-conductive polymer electrolyte interposed between the two electrodes.

Another capacitor is an electric double layer capacitor comprising a pair of polarizable electrodes containing at least activated carbon and an ion-conductive polymer electrolyte interposed between the two electrodes. In this electric double layer capacitor,
No ion conductive polymer electrolyte containing water is used. Further, the ion conductive polymer electrolyte used for the electric double layer capacitor is a copolymer of an ammonium maleate or a quaternary ammonium maleate and the above-mentioned monomer, and the polymer is an ammonium maleate or a maleic acid. The copolymerization ratio of the quaternary ammonium salt is preferably 0.5 mol or more based on 1 mol of the monomer.

Hydroxyalkyl acrylate, hydroxyalkyl methacrylate and vinylene carbonate are liquid substances by themselves, but when a polymerization initiator is added thereto and irradiated with actinic rays such as ultraviolet rays or heated, the polymerization reaction occurs. Can be solidified. Further, hydroxyalkyl acrylate and hydroxyalkyl methacrylate dissolve various electrolyte salts by the action of the terminal group OH, and become ion-conductive. On the other hand, vinylene carbonate dissolves various electrolyte salts by the action of the terminal group C ＝ O, and becomes ion conductive. Therefore, when an electrolyte salt is dissolved in hydroxyalkyl acrylate, hydroxyalkyl methacrylate or vinylene carbonate, and solidified by irradiation with actinic light or heating, a solid electrolyte having ion conductivity can be formed. In general, even in the liquid state, even those having high ionic conductivity, many of which have extremely reduced conductivity when solidified, but according to the present invention, a solid electrolyte having practically sufficient conductivity can be obtained. .

Examples of the electrolyte salt include hydroxyalkyl acrylate, hydroxyalkyl methacrylate or ammonium carboxylate dissolved in vinylene carbonate.
It is possible to use ammonium dicarboxylate, quaternary ammonium carboxylate, quaternary ammonium dicarboxylate and the like. In particular, when used for driving an aluminum electrolytic capacitor, quaternary ammonium maleate or morpholinium maleate is particularly useful for hydroxyalkyl acrylate and hydroxyalkyl methacrylate. When an aluminum electrolytic capacitor is made with a polymer electrolyte composed of these salts,
It has practically sufficient impedance characteristics as a high-voltage class capacitor, and can realize unprecedented high-temperature reliability.

Further, quaternary ammonium maleate, morpholinium maleate, quaternary ammonium oxalate, quaternary ammonium adipic acid salt, quaternary ammonium azelate, quaternary ammonium benzoate with respect to vinylene carbonate, Quaternary ammonium formate, quaternary ammonium citrate, quaternary ammonium succinate, quaternary ammonium salicylate, quaternary ammonium tartrate,
Particularly useful are ammonium sebacate, ammonium borodisalicylate, ammonium γ - resorcylate, ammonium lactate, ammonium glycolate, ammonium diphenylacetate, and the like. When an aluminum electrolytic capacitor is made of a polymer electrolyte composed of these salts, it has practically sufficient impedance characteristics as a low-voltage class capacitor, and can realize much higher-temperature reliability than ever before. The ion-conductive polymer electrolyte of the present invention comprises the above - mentioned copolymer as a base material and a second base material in the base material .
Has a configuration in which the electrolyte salt is dispersed. Then, the dissociated from the electrolyte salt ions Ru engaged in conductivity. The second electrolytic <br/> Shitsushio, rather than the first electrolyte salt used in the copolymerization, may be added to the copolymer obtained by separately prepared.

Generally, the ionic conductivity of an electrolyte is proportional to the product of the concentration of dissociated ions and the mobility. In order for the ion-conductive polymer electrolyte of the present invention to have sufficient ionic conductivity and high physical and chemical stability, it is preferable that the following points are satisfied. (1) When the dielectric constant of the monomer is increased and the electrolyte salt is dissolved in the monomer, the electrolyte salt is sufficiently ion-dissociated into cations and anions, and the concentration of these ions is maintained at a high level. (2) The anion of the electrolyte salt is bonded to the monomer by the copolymerization reaction, and has high physical or chemical stability.

The polymer electrolyte according to the present invention has the above (1)
Those satisfying the requirement (1) and using a copolymer further satisfy the requirement (2). For example, the polymerizable double bond in the above monomer has an acryloyl group CH ₂ ＣC
HCOO- is also hydroxyethyl group -C ₂ H ₄ OH corresponds respectively to the functional group expressing a high dielectric constant. In the electrolyte salt, the group having an ion dissociable and polymerizable double bond in the molecule corresponds to a C = C double bond in the molecule of maleic acid or fumarate. When the monomer and the electrolyte salt are mixed, the electrolyte salt is ionically dissociated into an anion portion composed of maleic acid and a cation portion composed of an ammonium salt due to the high dielectric constant provided by the hydroxyethyl group of hydroxyethyl acrylate. At this time, when an actinic ray such as an ultraviolet ray or an electron beam is irradiated, the acryloyl group of the monomer and a C = C double bond in the anion portion of the electrolyte salt partially undergo a copolymerization reaction, and in the following formula (1) A polymer compound represented by q = 2 can be formed. Using this as a skeleton, the polymer electrolyte of the present invention can be prepared using ions dissociated from the electrolyte salt monomethyltriethylammonium hydrogen maleate as a conductive species.

[0022]

Embedded image

In the formula, l _i , m _i , and n _i are integers of 1 or more, and q is an integer of 1 to 5. Further, as described above, the temperature characteristic of the ionic conductivity of the conventionally proposed polymer electrolyte is such that the logarithm of the ionic conductivity (Arrhenius plot of the ionic conductivity) is an upwardly convex curve with respect to the reciprocal of the absolute temperature. Show,
In the low temperature range, the rate of decrease in ionic conductivity was particularly large. In contrast, it was found that the polymer electrolyte of the present invention showed good linearity in the Arrhenius plot. This is because -OH in the skeleton portion of the electrolyte of the present invention.
It is considered that the group has an effect of improving the ion transportability. This effect is the same when vinylene carbonate is used as a monomer. In this case, it is considered that the C ＝ O group of the vinylene carbonate molecule acts similarly to the —OH group of the hydroxyethyl acrylate. Further, when the ion-conductive polymer electrolyte of the present invention is used for driving an aluminum electrolytic capacitor, if the water content is not more than 10% by weight, the withstand voltage is improved. This is considered to be due to the improvement of the repairability of the oxide film of the aluminum electrode due to the addition of water.

Further, the electric double layer capacitor formed by using the electrolyte of the present invention can obtain an unprecedentedly high capacity because the electrolyte contains a large amount of ions. Furthermore, since the electrolyte according to the present invention has no liquid component, the reliability is remarkably improved as compared with a conventional device using a liquid electrolyte. According to the present invention, a higher capacity and a higher voltage of an electric double layer capacitor can be realized.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail with reference to examples. Example 1 The ionic conductivity and high-temperature storage reliability of an ion-conductive polymer electrolyte composed of hydroxyethyl acrylate and maleate will be described. First,
A solution is prepared by dissolving the maleate shown in Table 1 in 10 g of hydroxyethyl acrylate. Next, 100 mg of benzyldimethyl ketal as a polymerization reaction initiator is added to this solution, and the mixture is sufficiently stirred to be dissolved. This was cast into a stainless steel vat to a thickness of 0.5 mm, irradiated with 5 J of light by a high-pressure mercury lamp in the air, and then heated at 100 ° C. for 1 hour to obtain an ion-conductive polymer electrolyte. I got a sheet.

The temperature characteristics of the ionic conductivity of the electrolyte prepared by the above method were measured by a known complex impedance method. The result is shown in FIG. Further, as an evaluation of the high-temperature storage reliability of the electrolyte, a change with time in ionic conductivity when stored in an unsealed state in an atmosphere of 105 ° C. in air was measured. The result is shown in FIG. The electrolyte for evaluation used here was a polymer electrolyte sheet shaped into a disk having a thickness of 0.5 mm and a diameter of 13 mm, and the ionic conductivity was measured at 30 ° C. FIG. 1 is an Arrhenius plot of conductivity in which the vertical axis is the logarithm of ionic conductivity and the horizontal axis is the reciprocal of the absolute temperature. As is clear from FIG. 1, according to the present invention, at room temperature, 1 × 10 ⁻⁴ S / cm or more, and −10 ° C.
However, a polymer electrolyte having an unprecedentedly high conductivity of 1 × 10 ⁻⁵ S / cm or more can be formed. Also, as is clear from FIG. 2, the high temperature (1
Despite the extremely harsh condition of storage (05 ° C.), it has an ion conductivity of 20% or more of the initial value even after storage for 500 hours.

[0027]

[Table 1]

In the present embodiment, benzyldimethyl ketal was added as a polymerization reaction initiator, and the polymerization reaction was carried out by irradiating ultraviolet rays. However, the polymerization reaction can be carried out by heating. For example, a polymer electrolyte prepared by adding 10 mg of α, α′-azobisisobutyronitrile instead of benzyldimethyl ketal as a polymerization reaction initiator and heating the mixture at 80 ° C. for 20 hours in a nitrogen gas atmosphere also has an ionic property. Similar effects were obtained in conductivity and high-temperature storage characteristics.

Next, the structure of the electrolyte was analyzed by nuclear magnetic resonance (hereinafter referred to as NMR) and elemental analysis of carbon, hydrogen and nitrogen (hereinafter referred to as CHN elemental analysis). As a result, it was found that the electrolyte formed a copolymer of hydroxyethyl acrylate and triethylmonomethylammonium hydrogen maleate, and used as a conductive species ions dissociated from triethylmonomethylammonium hydrogen maleate using this as a skeleton structure. . As an example of the NMR spectrum and CHN elemental analysis that are the basis of this structure determination,
The data of the sample A are shown in FIGS. 3, 4, 5 and 6, respectively. FIGS. 3 and 4 are NMR spectra of hydroxyethyl acrylate and triethylmonomethylammonium hydrogen maleate as reaction raw materials, respectively. FIGS. 5 and 6 are NMR spectra of an extract and a solid remaining after extraction, respectively, obtained by separating the electrolyte produced after the above-described reaction by the Soxhlet extraction method using chloroform as a solvent. In FIGS. 3 and 4, the peaks based on the double bond of the acrylic group and the maleic acid were 1 respectively.
N compared to those observed at 31 ppm and 136 ppm
FIG. 6 shows that these peaks have disappeared. This confirmed that the acrylic group of hydroxyethyl acrylate and maleic acid of triethyl monomethyl ammonium hydrogen maleate caused a double bond cleavage reaction. Next, Table 2 shows the results of CHN elemental analysis on solids remaining after extraction in the Soxhlet extraction method. Also, hydroxyethyl acrylate (HE
Table 3 shows the element configurations (atomic ratio, weight ratio) of A) and triethylmonomethylammonium hydrogen maleate (MaH3E1M).

[0030]

[Table 2]

[0031]

[Table 3]

Here, the analysis sample is MaH3E1
Assuming that the molar ratio of M to HEA is x: 1−x, the following equation is established from the analyzed value of nitrogen N of 2.57%. 100 × 14x / ｛(60 + 8 + 48) (1-x) +
(132 + 21 + 64 + 14) × x｝ = 2.57 From this, x = 0.27 and 1−x = 0.73. That is, the sample used here has a molar ratio of MaH3E1M to HEA of 0.27: 0.73, that is, 1: 3. The NMR spectrum of the extract separated by the Soxhlet extraction method was identical to the NMR spectrum of triethylmonomethylammonium hydrogen maleate in FIG. From the above analysis results, the electrolyte of the present example has a polymer skeleton of a copolymer of hydroxyethyl acrylate and triethyl monomethyl ammonium hydrogen maleate, and has an ion dissociated from triethyl monomethyl ammonium hydrogen maleate as a conductive species. It is determined that the electrolyte is an ion conductive polymer electrolyte.

Example 2 In this example, electrolytes having different copolymerization ratios were prepared by using hydroxyethyl acrylate and triethylmonomethylammonium hydrogen maleate by changing the molar ratio of mixing them. First,
To 1 mole (116 g) of hydroxyethyl acrylate,
As shown in Table 4, solutions were prepared in which various amounts of triethyl monomethyl ammonium hydrogen maleate were dissolved. Next, benzyldimethyl ketal as an initiator of a polymerization reaction is added to this solution in an amount corresponding to 1% by weight of the solution, and the mixture is sufficiently stirred and dissolved. This solution is cast into a stainless steel vat to a thickness of 0.5 mm, and is irradiated with 1 J of light at 30 mW / cm ² in air by a high-pressure mercury lamp. Next, this is heated in air at 110 ° C. for 1 hour, and then vacuum dried at 110 ° C. for 20 hours. Thus, a sheet of the ion-conductive polymer electrolyte was obtained by removing the unreacted hydroxyethyl acrylate.

[0034]

[Table 4]

The structure of the electrolyte prepared by the above method was analyzed by NMR and CHN elemental analysis in the same manner as in Example 1. As a result, the electrolyte formed a copolymer of hydroxyethyl acrylate and triethylmonomethylammonium hydrogen maleate in a molar ratio (MaH3E1M / HEA) shown in Table 4, and used this as a skeleton structure to form a hydrogen maleate ion and triethyl monomethyl ammonium. It has been found that the structure has ammonium ions as a conductive species. As a result, it was found that practically necessary conductivity was obtained when the copolymerization ratio was larger than 0.1.

Next, the ionic conductivity of the electrolyte was measured by a known complex impedance method. The result is shown in FIG. FIG. 7 is an Arrhenius plot of the conductivity in which the vertical axis is the logarithm of the ion conductivity and the horizontal axis is the reciprocal of the absolute temperature. As shown in FIG. 7, according to the present invention, samples G, H, I, J, and K in which the composition ratio of the electrolyte salt is 50 mol% or more.
It has been found that has a sufficiently high conductivity for practical use and does not have a particularly large decrease in conductivity in a required temperature range. Further, as an evaluation of the high-temperature storage reliability of the above-mentioned electrolytes G, H, I, J, and K, a change with time in ionic conductivity when stored in a nitrogen atmosphere at 110 ° C. in an unsealed state was measured. The result is shown in FIG. For this measurement, a thickness of 0.5 m
The ionic conductivity was measured at 30 ° C. using a polymer electrolyte sheet shaped to m and 13 mm in diameter. As can be seen from FIG. 8, despite the extremely harsh condition of storing at a high temperature in an unsealed state, even after 500 hours of storage at 110 ° C., it has an ion conductivity of 50% or more of the initial value. Turned out to be.

Example 3 In Example 1, hydroxyethyl acrylate and triethylmonomethylammonium hydrogen maleate were used, benzyldimethyl ketal was added as a polymerization initiator, and 1 J ultraviolet light at an intensity of 30 mW / cm ² was used. The reaction was performed by light irradiation.
In this example, ionic conductivity and high-temperature storage characteristics when the reaction conditions are changed and the molecular weight of the obtained skeleton structure is changed will be described. In this example, the preparation steps were the same as in Example 1 except that the amount of benzyl dimethyl ketal, which was the initiator of the polymerization reaction, and the irradiation intensity of ultraviolet rays were changed.
Further, the high-temperature storage characteristics were 11
The conductivity after 500 hours without sealing at 0 ° C. was evaluated. The results are shown in Table 5.

[0038]

[Table 5]

As can be seen from Table 5, those having a low irradiation amount of ultraviolet rays and a low polymerization initiator concentration and having a small average molecular weight of the obtained copolymer have low storage reliability but high initial conductivity. Conversely, it was found that those having a large average molecular weight of the copolymer had low initial conductivity but high storage reliability. As a result, it was found that those having practically excellent characteristics had an average molecular weight of 1,000 to 1,000,000.

Example 4 The ionic conductivity and high-temperature storage reliability of an ionic conductive polymer electrolyte composed of vinylene carbonate and maleate will be described. First, a solution in which maleate shown in Table 6 was dissolved in 10 g of vinylene carbonate was prepared. Next, 10 mg of benzyldimethyl ketal as an initiator of the polymerization reaction is added to this solution, and the mixture is sufficiently stirred and dissolved. Put this in a stainless steel vat.
The film was cast to a thickness of 5 mm, irradiated with 5 J of light from a high-pressure mercury lamp in the air, and then heated at 100 ° C. for 1 hour to obtain an ion-conductive polymer electrolyte sheet.

The temperature characteristics of the ionic conductivity of the electrolyte prepared by the above method were measured by a known complex impedance method. The result is shown in FIG. In addition, as an evaluation of the high-temperature storage reliability of the electrolyte, a change with time in ionic conductivity when stored in an atmosphere of 110 ° C. in air without sealing was measured. The results are shown in FIG. The evaluation electrolyte used here has a thickness of 0.5 mm and a diameter of 13 mm.
The ion conductivity was measured at 30 ° C. using a polymer electrolyte sheet shaped into a mm disk. FIG. 9 is an Arrhenius plot of the conductivity in which the vertical axis is the logarithm of the ionic conductivity and the horizontal axis is the reciprocal of the absolute temperature. As apparent from FIG. 9, according to the present invention, at room temperature, 1 × 10 ⁻⁴ S / cm or more, and −
Even at 10 ° C., a polymer electrolyte having an unprecedented high conductivity of 1 × 10 ⁻⁵ S / cm or more can be constituted. Further, as is clear from FIG. 10, despite the extremely severe condition of high-temperature storage in an unsealed state, it has an ion conductivity of 20% or more of the initial value even after 500 hours. It has been found.

[0042]

[Table 6]

In this example, benzyldimethyl ketal was added as a polymerization reaction initiator, and the polymerization reaction was carried out by irradiating ultraviolet rays. However, the polymerization reaction can be carried out by heating. For example, a polymer electrolyte prepared by adding 10 mg of α, α′-azobisisobutyronitrile instead of benzyldimethyl ketal as a polymerization reaction initiator and heating the mixture at 50 ° C. for 20 hours in a nitrogen gas atmosphere may be used. Similar effects were obtained in ionic conductivity and high-temperature storage characteristics.

Embodiment 5 A specific example of an aluminum electrolytic capacitor prepared by using an ion conductive electrolyte as a driving electrolyte will be described. FIG. 11 is a front view showing a cross section of a part of an aluminum electrolytic capacitor formed by using the electrolyte of the present invention. The anode connector 1 is spot-welded to an electrode made of aluminum foil having a thickness of 0.05 mm, an etching hole diameter of about 1 to 5 μm, and a size of 3 cm × 100 cm. Next, boric acid kept at a temperature of 90 ° C /
Borax aqueous solution (boric acid 80 g + borax 8 g / water 1000
ml), and a current of 30 A is applied for 15 minutes.
Anode foil 2 was formed by applying a voltage of 00 V for 5 hours. Further, the thickness is 0.05 mm, the diameter of the etching hole is about 1 to 5 microns, and the size is 3 cm × 100 cm.
Electrode 3 made of aluminum foil
Was spot-welded to produce a cathode.

Next, a stock solution of a polymer electrolyte is prepared. N, N maleic acid to 10 g of hydroxyethyl acrylate
Make a solution of 5 g of dimethylmorpholinium and 0.5 g of water. Next, 100 mg of benzyldimethyl ketal was added to this solution as a polymerization initiator,
Dissolve with sufficient stirring. Subsequently, the undiluted polymer electrolyte solution was applied to both sides of the anode foil 2 to a thickness of 0.1 mm, respectively, and then 300 mW / air in air by a high-pressure mercury lamp.
By performing light irradiation for 20 seconds at an irradiation intensity of cm ² ,
An ion conductive polymer electrolyte layer 5 was formed. Next, the negative electrode aluminum electrode 3 was pressed on the surface of the electrolyte 5 on one side of the anode. Finally, this was wound into a roll, thereby producing an aluminum electrolytic capacitor a using an ion-conductive polymer electrolyte. Next, as a comparative example, an unsealed aluminum electrolytic capacitor b was prepared in the same manner as the capacitor a using a known electrolyte obtained by dissolving 20 g of ammonium 1,6-decanedicarboxylate in 80 g of ethylene glycol. The production method is the same as that used for the aluminum electrolytic capacitor a, using the same anode foil and cathode foil, and a roll of kraft paper with a separator having a density of 0.7 g / cm ³ , a thickness of 50 μm, and a size of 3 cm × 4 cm. After that, the electrolyte solution was impregnated under reduced pressure at room temperature under a pressure of 5 Torr for 1 minute. The aging step was performed by applying 400 V at 80 ° C. for 2 hours to the element a, and applying 400 V to the element b at room temperature for 24 hours.

For the aluminum electrolytic capacitor a of the example and the capacitor b of the comparative example prepared by the above method, as an accelerated test for evaluating the stability of the electrolyte during high-temperature storage,
Capacitance and ta in unsealed storage at 105 ° C
The change over time of nδ was measured, and the results were shown in FIG.
2 and FIG. Measurement is 30 ° C, 120Hz
I went in. As is clear from FIGS. 12 and 13, the capacitor b of the comparative example using the conventionally used electrolyte using ethylene glycol as a solvent deteriorates the characteristics early due to high-temperature storage. It can be seen that the capacitor "a" made of the above electrolyte has sufficient reliability.

Example 6 The electrolyte prepared in Example 5 contains 3.2% by weight of water. In this example, deterioration of the capacitor withstand voltage and tan δ after high-temperature storage when the water content of the electrolyte was variously changed were evaluated, and a practically effective water content was examined. The structure and material of the device of this embodiment are the same as those used in the fifth embodiment. The withstand voltage was evaluated by measuring the spark generation voltage when a constant current of 30 mA was applied. The aging treatment was performed by applying a spark generation voltage of each element at 80 ° C. for 2 hours. The high-temperature preservation test was performed in the same manner as in Example 4 in an unsealed state at 105 ° C.
Performed by storing for 0 hours. Table 7 shows the results. As is evident from Table 7, the electrolyte to which water was added was able to obtain significantly improved withstand voltage and tan δ as compared with the electrolyte to which water was not added (containing 0.3% by weight as measured). However, when the amount of water added exceeds 10% by weight, the withstand voltage tends to decrease. from this result,
When the electrolyte of the present invention is applied to an aluminum electrolytic capacitor, the withstand voltage and tan δ are improved by adding water in a range not exceeding 10% by weight to the electrolyte. In this embodiment, maleic acid N, N-
Although dimethylmorpholinium was used, it was confirmed that, even when the maleate shown in Example 1 was used, the amount of water to be added was within the above-mentioned weight range.

[0048]

[Table 7]

Embodiment 7 In Embodiment 5, a polymer electrolyte composed of hydroxyethyl acrylate and maleate was used for driving a capacitor. In this embodiment, vinylene carbonate and various carboxylates or dicarboxylates were used. An example of a capacitor using a polymer electrolyte composed of an acid salt for driving is shown. In the configuration of the polymer electrolyte of this example, 10 g of vinylene carbonate was used, and predetermined amounts of the salts shown in Tables 8 and 9 were used. Other configurations and materials
This is the same as that used in the fifth embodiment. Evaluation of withstand voltage
The measurement was performed by measuring the spark generation voltage when a constant current of 30 mA was applied. The aging treatment was performed by applying a spark generation voltage of each element at 80 ° C. for 2 hours. The high-temperature preservation test was performed by storing in an unsealed state at 105 ° C. for 100 hours in the same manner as in Example 4. Table 8 and Table 9 show the increase rate of tan δ before and after storage. As is clear from Tables 8 and 9, it was confirmed that each of the aluminum electrolytic capacitors composed of the polymer electrolyte shown in this example had excellent reliability. In this example, the amount of water remaining in the polymer electrolyte was 1% by weight or less.

[0050]

[Table 8]

[0051]

[Table 9]

[Embodiment 8] In the following, an example in which an ion-conductive polymer electrolyte is applied to an electric double layer capacitor will be described. FIG. 14 shows a typical configuration of the electric double layer capacitor of the present embodiment. In the figure, 11 is an electrode made of activated carbon and an ion conductive polymer electrolyte, 12 is an electrolyte layer made of the same material as the ion conductive polymer electrolyte, and 13 is a current collecting electrode made of a metal foil. Aluminum, stainless steel, or the like can be used as the metal material of the current collecting electrode. However, it is not particularly limited to these materials. Reference numeral 14 denotes a sealing material which is generally obtained by thermocompression bonding an electrically insulating film such as polypropylene on the inner surface of a metal foil such as aluminum. Electrolyte layer 12
By forming a porous film made of an electrically insulating material such as polypropylene as a carrier, mechanical strength and short-circuit resistance can be improved.

First, a method for producing the ion-conductive polymer electrolyte of this embodiment and a polarizable electrode comprising the same and activated carbon will be described. Hydroxyethyl acrylate 10g
(0.086 mol) and 20 g (0.087 mol) of triethylmonomethylammonium hydrogen maleate are stirred and mixed, and cast into a stainless steel vat to a thickness of 0.5 mm. Further, the average particle diameter is 2 μm, the specific surface area is 2500.
m ² / g, 10 g of activated carbon having an average micropore diameter of 20 Å, 10 g of hydroxyethyl acrylate
g, triethylmonomethylammonium hydrogen maleate 20 g, and methyl ethyl ketone 35 g are placed in an alumina ball mill and stirred for 24 hours to be pulverized. next,
This is cast into a stainless steel bat to a size of 20 cm × 80 cm. The above two kinds of stock solutions were irradiated with an electron beam in a nitrogen atmosphere to obtain an electrolyte sheet and an electrode sheet, respectively. In addition, about the electrode sheet, after irradiation with an electron beam, 11 mm
By storing at 0 ° C. for 1 hour, methyl ethyl ketone present in the sheet was removed. The irradiation conditions of the electron beam were 750 keV for the accelerating voltage and 3 Mr for each of the irradiation doses.
ad and 8Mrad.

From the electrode sheet thus prepared, 2
Two electrodes having a size of 0 cm × 10 cm are cut out, and an electrolyte layer having a size of 21 cm × 11 cm is cut out of the electrolyte sheet. The above-mentioned electrodes are pressed on both surfaces of the electrolyte layer. Further, a 50-μm-thick aluminum foil was pressed against the back side of the electrode, and the whole was sealed with a sealing material for sealing a 0.1-mm-thick polypropylene on the inner surface of the aluminum foil. An example electric double layer capacitor was made. The sealing method was performed by pressing the end surface of the sealing material at a temperature of 170 ° C. for 5 seconds. For the capacitor manufactured as described above,
A charge / discharge test of 0 to 2.5 V was performed at 0 ° C. at a constant current of 10 mA. FIG. 15 shows a charge / discharge curve at the 100th cycle after the start of the test. From this test, the discharge capacity per g of activated carbon was calculated to be 38F. Equation 1 shows the calculation formula.

[0055]

(Equation 1)

Next, the above-mentioned charge / discharge test was performed in air at 85 ° C., and the cycle change of the discharge capacity was measured. The charge / discharge current was 10 mA. FIG. 16 shows the result. FIG.
In the graph, the horizontal axis represents the number of cycles, and the vertical axis represents the discharge capacity. As is clear from FIG.
Tests over 00 cycles have shown that no significant degradation occurs. In this embodiment, the polymerization reaction is performed by irradiation with an electron beam, but the polymerization reaction can be performed by heating. For example, 30 mg of α, α′-azobisisobutyronitrile was added as a polymerization initiator, and the polymer electrolyte sheet and the electrode sheet were cured by heating at 80 ° C. for 20 hours in a nitrogen gas atmosphere. The capacitor also showed similar characteristics in the capacitance and cycle tests.

[Embodiment 9] First, a method of manufacturing an ion-conductive polymer electrolyte of this embodiment and a polarizable electrode comprising the same and activated carbon will be described. 10 g of vinylene carbonate
(0.12 mol) and 20 g (0.098 mol) of trimethylmonoethylammonium hydrogen maleate are stirred and mixed, and cast into a stainless steel vat to a thickness of 0.5 mm. Further, the average particle diameter is 2 μm, the specific surface area is 2500.
m ² / g, 10 g of activated carbon having a micropore average diameter of 20 Å, 10 g of vinylene carbonate, 20 g of trimethyl monoethyl ammonium maleate, and 35 g of methyl ethyl ketone were placed in an alumina ball mill,
The mixture is stirred and pulverized for 24 hours, and cast into a stainless steel vat to a size of 20 cm × 80 cm. The above two kinds of stock solutions were irradiated with an electron beam in a nitrogen atmosphere to obtain an electrolyte sheet and an electrode sheet, respectively. After the electron beam irradiation, the electrode sheet was stored at 110 ° C. for 1 hour under a reduced pressure of 10 mmHg to remove methyl ethyl ketone present in the sheet. The irradiation conditions of the electron beam were such that the acceleration voltage was 750 keV and the irradiation dose was 3 Mrad and 8 Mrad, respectively.

From the electrode sheet thus prepared, 2
Two electrodes having a size of 0 cm × 10 cm are cut out, and an electrolyte layer having a size of 21 cm × 11 cm is cut out of the electrolyte sheet. The above-mentioned electrodes are pressed on both surfaces of the electrolyte layer. Further, a 50-μm-thick aluminum foil was pressed against the back side of the electrode, and the whole was sealed with a sealing material for sealing a 0.1-mm-thick polypropylene on the inner surface of the aluminum foil. An example electric double layer capacitor was made. The sealing method was performed by pressing the end surface of the sealing material at a temperature of 170 ° C. for 5 seconds. For the capacitor manufactured as described above,
A charge / discharge test of 0 to 2.5 V was performed at 0 ° C. at a constant current of 10 mA. The charge / discharge curve at the 100th cycle after the start of the test is shown in FIG. From this test, the discharge capacity per 1 g of activated carbon was calculated to be 40F. Next, the charge / discharge test was performed in air at 85 ° C., and the cycle change of the discharge capacity was measured. The charge / discharge current was 10 mA. FIG. 18 shows the result. From FIG. 18, it was found that the element of the example did not cause significant deterioration in a test over 5000 cycles. In this embodiment, the polymerization reaction is performed by irradiation with an electron beam, but the polymerization reaction can be performed by heating. For example, 30 mg of α, α′-azobisisobutyronitrile was added as a polymerization initiator, and the polymer electrolyte sheet and the electrode sheet were cured by heating at 80 ° C. for 20 hours in a nitrogen gas atmosphere. The capacitor also showed similar characteristics in the capacitance and cycle tests.

Example 10 In the polymer electrolyte shown in Example 8, 1 mole of maleate was added to 1 mole of hydroxyethyl acrylate as a polymer raw material, and in Example 9, 0 mole was added to 1 mole of vinylene carbonate. 0.82 mole of maleate was used. In this embodiment, a capacitor is formed by preparing an electrolyte by changing the types and mixing ratios of the polymer raw materials and maleate used, and a capacitor is formed in the same manner as in the previous embodiment.
The discharge capacity at the 0th cycle was evaluated. Except for the composition of the polymer electrolyte, all configurations were the same as those in Examples 1 and 2. Table 10 shows the results.

[0060]

[Table 10]

In Table 10, abbreviations represent the following compounds. AHE: hydroxyethyl acrylate, TV: vinylene carbonate, Ma3E1M: triethylmonomethylammonium hydrogen maleate, Ma3M1E: trimethylmonoethylammonium hydrogen maleate, Ma4E: tetraethylammonium hydrogen maleate, MaA: ammonium hydrogen maleate. Table 1 shows that a sufficient capacity can be obtained when the maleic acid salt is used in an amount of 0.5 mol or more per 1 mol of the polymer raw material in the constitution of the polymer electrolyte.

[0062]

The ion-conductive polymer electrolyte of the present invention comprises:
An aluminum electrolytic capacitor that has sufficient ionic conductivity and extremely high physical and chemical stability, and that is used for driving, has the same electrical conductivity as that using a liquid electrolyte. In addition to having characteristics, it has extremely high reliability that could not be realized with a conventional electrolytic solution. According to the present invention, it is possible to obtain an electric double-layer capacitor containing no liquid component and having particularly long-term reliability.

[Brief description of the drawings]

FIG. 1 is a diagram showing temperature characteristics of ionic conductivity of an ion-conductive polymer electrolyte in Example 1 of the present invention.

FIG. 2 is a graph showing the high-temperature storage characteristics of the ionic conductivity of the ion-conductive polymer electrolyte in Example 1.

FIG. 3 is a diagram showing an NMR spectrum of hydroxyethyl acrylate as a monomer used in Examples of the present invention.

FIG. 4 is a view showing an NMR spectrum of an electrolyte salt of triethylmonomethylammonium hydrogen maleate used in an example of the present invention.

FIG. 5 is a view showing an NMR spectrum of an extract obtained by separating an electrolyte produced by a reaction between the above-mentioned monomer and an electrolyte salt by a Soxhlet extraction method using chloroform as a solvent.

FIG. 6 is a diagram showing an NMR spectrum of a solid remaining after extraction obtained by separating the electrolyte produced by the reaction between the monomer and an electrolyte salt by Soxhlet extraction using chloroform as a solvent.

FIG. 7 is a diagram showing the ionic conductivity of various electrolytes of Example 2.

FIG. 8 is a diagram showing a change over time in the ionic conductivity of various electrolytes.

FIG. 9 is a diagram showing temperature characteristics of ionic conductivity of an ion-conductive polymer electrolyte in Example 4.

FIG. 10 is a graph showing the high-temperature storage characteristics of the ionic conductivity of the ion-conductive polymer electrolyte in Example 4.

FIG. 11 is a front view showing a part of an aluminum electrolytic capacitor in a cross section in Example 5;

FIG. 12 is a diagram showing the high-temperature storage characteristics of the capacitance of the aluminum electrolytic capacitor in Example 5.

FIG. 13 shows t of the aluminum electrolytic capacitor in the fifth embodiment.
It is a figure which shows the high temperature storage characteristic of an (delta).

FIG. 14 is a longitudinal sectional view of the electric double layer capacitor in the embodiment of the present invention.

FIG. 15 is a diagram showing a charge / discharge curve of the electric double layer capacitor of Example 8.

FIG. 16 is a diagram showing the cycle characteristics of the discharge capacity of the electric double layer capacitor of Example 8.

FIG. 17 is a view showing a charge / discharge curve of the electric double layer capacitor of Example 9.

FIG. 18 is a diagram showing the cycle characteristics of the discharge capacity of the electric double layer capacitor of Example 9.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Anode connector 2 Anode 3 Cathode 4 Cathode connector 5 Electrolyte layer 11 Polarized electrode 12 Electrolyte layer 13 Collector electrode 14 Sealing material

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-37014 (JP, A) JP-A-54-115147 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01G 9/02

Claims (12)

(57) [Claims] 1. A hydroxyalkyl acrylates, and at least one monomer selected from the group consisting of hydroxyalkyl methacrylate and vinylene carbonate, in the molecule
Ion-conductive polymer electrolyte which is characterized by comprising a copolymer of a first electrolyte salt having a polymerizable double bond. 2. The method according to claim 1, wherein said first electrolyte salt is selected from the group consisting of ammonium carboxylate, ammonium dicarboxylate, morpholinium dicarboxylate, quaternary ammonium carboxylate and quaternary ammonium dicarboxylate. The ion-conductive polymer electrolyte according to the above. Wherein a first electrolyte salt maleate or fumarate, the copolymerization molar ratio of the copolymer (a
2. The ion-conductive polymer electrolyte according to claim 1, wherein ( 1 ) the electrolyte salt / monomer) is 0.1 or more, and the average molecular weight of the copolymer is 1,000 to 1,000,000. 4. A further, Ma maleic acid hydrogen quaternary ammonium, hydrogen maleate N, N - dimethyl morpholinium,
Quaternary ammonium hydrogen fumarate and hydrogen fumarate N,
4. The method according to claim 1, further comprising at least one second electrolyte salt selected from the group consisting of N - dimethylmorpholinium.
An ion-conductive polymer electrolyte according to any of the above. 5. The ion conductive polymer electrolyte according to any one of claims 1-4 for the 10 wt% water in an amount not exceed. 6. hydroxyalkyl acrylates, heavy in the molecule at least one monomer selected from the group consisting of hydroxyalkyl methacrylate and vinylene carbonate
Dissolving a first electrolyte salt having a compatible double bond, and irradiating the solution obtained above with actinic rays or applying heat to cure the solution. A method for producing a conductive polymer electrolyte. Wherein said first electrolyte salt ammonium carboxylate salt, claim is selected dicarboxylic acid ammonium salts, dicarboxylic acid morpholinium salt, carboxylic acid quaternary ammonium salt, and the group consisting of dicarboxylic acid quaternary ammonium salt 6 A method for producing the ion-conductive polymer electrolyte according to the above. 8. The method according to claim 1, wherein the first electrolyte salt is a maleate salt.
Is a fumarate, and the copolymerization molar ratio of the copolymer (the
1 electrolyte salt / monomer) is 0.1 or more and
The average molecular weight of the copolymer is 1000 or more and 1,000,000 or less
7. A method for producing an ion-conductive polymer electrolyte according to claim 6 . 9. A quaternary ammonium hydrogen maleate.
N, N-dimethylmorpholinium hydrogen maleate;
Quaternary ammonium hydrogen fumarate and aqueous fumaric acid
Selected from the group consisting of elemental N, N-dimethylmorpholinium
6. that having a step of adding a second electrolyte salts
9. The method for producing an ion-conductive polymer electrolyte according to any one of items 1 to 8 . 10. A negative electrode made of aluminum, an anode having a dielectric layer made of aluminum oxide, and includes an electrolyte interposed between both electrodes, the electrolyte, according to any of claims 1 to 5 ions An electrolytic capacitor that is a conductive polymer electrolyte. 11. A pair of polarizable electrodes including at least activated carbon, and an electrolyte interposed between the two electrodes,
An electric double layer capacitor, wherein the electrolyte is the ion-conductive polymer electrolyte according to any one of claims 1 to 5 . 12. The polymer in the ion conductive polymer electrolyte is a copolymer of an ammonium maleate salt or a quaternary ammonium maleate salt and the monomer, and the ammonium maleate salt or the quaternary ammonium maleate salt is used. The electric double layer capacitor according to claim 11 , wherein a copolymerization ratio of the monomer is 0.5 mol or more with respect to 1 mol of the monomer.