JP2012146775A - Electrochemical device electrode and electrochemical device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrochemical device electrode and an electrochemical device which can effectively suppress reduction in electrostatic capacitance and increase in internal resistance after repeated charges/discharges.SOLUTION: The electrochemical device has had its active material constituting polarizable electrode layers 12, 22 of a cathode 10 and an anode 20 subjected to esterification processing, which resulted in a hydroxyl group or a carboxyl group present on the surface of the active material being replaced with an amino group having an alkyl chain. Therefore, it is possible to suppress the amount of protons generated by a charge/discharge from the hydroxyl group or the carboxyl group present on the surface of the active material, as well as protons generated by electrolysis of moisture content in a nonaqueous electrolyte can be captured by the amino group, thus allowing to effectively suppress reduction in electrostatic capacitance and increase in internal resistance after repeated charges/discharges.

Description

  The present invention relates to various electrochemical devices such as an electric double layer capacitor, a lithium ion capacitor, a redox capacitor, and a lithium ion secondary battery using a nonaqueous electrolytic solution and an electrode containing an active material.

  As a polarizable electrode layer of an electrode of a conventional electric double layer capacitor, for example, an electrode containing an active material such as polyacene, polyaniline, activated carbon, a conductive agent such as carbon black, and a binder such as styrene butadiene rubber is known. (For example, refer to Patent Document 1).

  Such an electric double layer capacitor is manufactured so that the water content in the non-aqueous electrolyte is reduced as much as possible. However, the water is adsorbed in the pores of the active material of the electrode. It is difficult to completely remove moisture mixed in the electrolyte.

Also, the non-aqueous when the water in the electrolytic solution is contained, the water protons occur by electrolyzing by repeating charge and discharge, BF ₄ in its protonated and non-aqueous electrolyte ^- electrolyte such anions The components may react with each other, thereby causing decomposition of a nonaqueous solvent such as propylene carbonate in the nonaqueous electrolytic solution. In addition, the decomposition of the nonaqueous solvent decreases the capacitance of the electric double layer capacitor and increases the internal resistance.

In addition, since functional groups such as hydroxyl groups and carboxyl groups exist on the surface of the electrode, protons are generated from the functional groups by repeated charge and discharge, and the protons and electrolytes such as BF ₄ ⁻ in the nonaqueous electrolytic solution. The anion component reacts with the same result as when water is electrolyzed. Further, the functional group may be detached from the electrode by repeated charge and discharge. In this case, gas is generated by the detached functional group, and the increase in the internal pressure of the electric double layer capacitor or the container Invite the expansion.

  In order to prevent the deterioration of the non-aqueous electrolyte as described above, it is known to attach an organic polymer such as polyallylamine to the surface of the electrode (see, for example, Patent Document 2). However, when the surface of the electrode is covered with an organic polymer in this way, the pores of the active material are covered, resulting in a significant decrease in capacitance.

JP 2010-040765 A JP 2002-117851 A

  The present invention has been made in view of the above problems, and an object thereof is an electrochemical device capable of effectively suppressing a decrease in capacitance and an increase in internal resistance after repeated charge and discharge. It is to provide an electrode and an electrochemical device.

  In order to achieve the above object, the present invention provides an electrode for an electrochemical device containing an active material, the active material having a group represented by the following formula (1) on the surface thereof, wherein R1 And R2 is an alkyl group having 1 to 3 carbon atoms, and n is an integer of 1 to 5.

  The present invention also relates to an electrode for an electrochemical device containing an active material, wherein the active material has a group represented by the following formula (2) on the surface thereof, wherein R3 and R4 are carbon numbers. Is an alkyl group of 1 to 3, and n is an integer of 1 to 5.

  Moreover, this invention is an electrochemical device provided with the said electrode and non-aqueous electrolyte.

  As described in detail below, according to the electrode for an electrochemical device and the electrochemical device according to the present invention, it is possible to effectively suppress a decrease in capacitance and an increase in internal resistance after repeated charge and discharge. .

  The above object and other objects, structural features, and operational effects of the present invention will become apparent from the following description and the accompanying drawings.

Side surface sectional drawing of the electric double layer capacitor of one Embodiment of this invention Plan view of electric double layer capacitor Side sectional view of electric double layer capacitor with film package expanded Examples of amino alcohols of formula (3) Examples of amino alcohols of formula (3) Examples of amino alcohols of formula (3) Examples of amino acids of formula (4) Examples of amino acids of formula (4) Examples of amino acids of formula (4) Schematic diagram when the carboxyl group is replaced by amino alcohol Schematic diagram when the hydroxyl group is replaced by an amino acid Table showing experimental results Table showing experimental results Table showing experimental results

  Hereinafter, an electric double layer capacitor as an embodiment to which the present invention is applied will be described in detail.

  In the electric double layer capacitor of the present embodiment, an electrolyte is dissolved in a non-aqueous solvent, a power storage element B having a positive electrode 10 as an electrode, a negative electrode 20 as an electrode, and a separator 30 interposed between the positive electrode 10 and the negative electrode 20. A non-aqueous electrolyte solution, a film package 40 made of a laminate film and encapsulating the electricity storage element B and the non-aqueous electrolyte, one end connected to the electricity storage element B and the other end led out from the film package 40 And a pair of terminals 50. The positive electrode 10 and the negative electrode 20 are each formed by forming polarizable electrode layers 12 and 22 on the surfaces of current collectors 11 and 21 made of metal foil, for example, and the polarizability of the polarizable electrode layer 12 and the negative electrode 20 of the positive electrode 10. It arrange | positions so that the electrode layer 22 may face. The separator is made of cellulose, polypropylene, polyethylene, fluorine resin, etc., and other materials can be used as long as they can be impregnated with a non-aqueous electrolyte. Further, the separator 30 is disposed between the polarizable electrode layers 12 and 22 of the positive electrode 10 and the negative electrode 20 facing each other as described above, and the storage element B is laminated in the order of the positive electrode 10, the separator 30, and the negative electrode 20. Have a laminated structure. In addition, since the separator 30 between the positive electrode 10 and the negative electrode 20 is impregnated with the non-aqueous electrolyte, the electrical interface is formed at the contact interface between the polarizable electrode layers 12 and 22 of the positive electrode 10 and the negative electrode 20 and the non-aqueous electrolyte. A multilayer is formed. A known structure used for a film package type electric double layer capacitor can be applied to the storage element B and the film package 40.

[Positive electrode layer of positive electrode and negative electrode]
The polarizable electrode layers 12 and 22 of the positive electrode 10 and the negative electrode 20 may have a known material and structure used for the polarizable electrode layer of the electric double layer capacitor. For example, polyacene (PAS), polyaniline (PAN) , Containing active materials such as activated carbon, conductive aids such as carbon black, graphite and metal powder, polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), styrene butadiene rubber (SBR) and carboxymethyl cellulose (CMC) A binder such as) is also contained if necessary. Examples of the activated carbon raw material include sawdust, coconut shell, phenol resin, various heat resistant resins, pitch, etc. Examples of the heat resistant resin include polyimide, polyamide, polyamideimide, polyetherimide, polyethersulfone, Preferred examples include polyether ketone, bismaleimide triazine, aramid, fluororesin, polyphenylene, polyphenylene sulfide and the like. These can be used alone or in combination of two or more.

  The polarizable electrode layers 12 and 22 can be formed on the surfaces of the current collectors 11 and 21 as follows. In addition, the following is an example and it is also possible to form it by other known methods for forming a polarizable electrode layer.

  First, an electrode slurry is formed by dispersing an active material such as polyacene, polyaniline, activated carbon, and the like, a conductive assistant, and a binder in a solvent, and the electrode slurry is used as a current collector 11 of the positive electrode 10 and the negative electrode 20. , 12 are applied to the surfaces of the electrodes 12 and dried to form the polarizable electrode layers 12, 22 on the current collectors 11, 12. The active material is powdery, granular, or short fiber. The active material is subjected to a treatment for esterifying the functional group on the surface before being dispersed in the solvent to form an electrode slurry. The functional group is a hydroxyl group or a carboxyl group.

  As an example of the treatment method for the esterification, 10 g of a powdered active material is dispersed in 3 g of amino alcohol of the following formula (3) in the presence of carbodiimide, and then stirred for 24 hours while heating at 80 ° C. The method of doing is mentioned. In the aminoalcohol of the formula (3), R1 and R2 are alkyl groups having 1 to 3 carbon atoms, and n is an integer of 1 to 5. Examples of amino alcohols of the formula (3) are shown in Examples 1 to 27 in FIGS.

  Further, as another example of the treatment method for esterification, 10 g of a powdery active material is dispersed in 3 g of an amino acid of the following formula (4) in the presence of carbodiimide, and then heated to 80 ° C. while being heated to 24 ° C. The method of stirring for a time is mentioned. In the amino acid of the formula (4), R3 and R4 are alkyl groups having 1 to 3 carbon atoms, and n is an integer of 1 to 5. Examples of amino acids of formula (4) are shown in Examples 28-54 of FIGS.

  As shown in the schematic diagram of FIG. 10, the carboxyl group of the surface SR of the active material is esterified with the amino alcohol of the formula (3), and the group of the formula (1) is bonded to the surface SR of the active material. Moreover, as shown in the schematic diagram of FIG. 11, the hydroxyl group of the surface SR of the active material is esterified with the amino acid of the formula (4), and the group of the formula (2) is bonded to the surface SR of the active material.

[Non-aqueous electrolyte]
The following supporting electrolyte is dissolved in the following nonaqueous solvent.

[Nonaqueous solvent]
The non-aqueous solvent is a mixture of one or a plurality of solvents included in any of cyclic carbonate, chain carbonate, cyclic ester, chain ester, cyclic ether, chain ether, nitriles, and sulfur-containing compounds. Use solvent.

  Examples of cyclic carbonates include ethylene carbonate, propylene carbonate, butylene carbonate, vinylene carbonate, etc. Examples of chain carbonates include dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate, methyl propyl carbonate, methyl isopropyl carbonate. Examples of cyclic esters include γ-butyrolactone, γ-valerolactone, 3-methyl-γ-butyrolactone, 2-methyl-γ-butyrolactone, and examples of chain esters include formic acid. Methyl, ethyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, methyl butyrate, methyl valerate, etc., and examples of cyclic ethers include 1,4-dioxane, 1,3-dioxolane, tetrahydrofuran, 2- Examples include chain ethers such as 1,2-dimethoxyethane, 1,2-diethoxyethane, and the like. Examples of nitriles include acetonitrile, propanenitrile, glutaronitrile, adiponitrile, methoxyacetonitrile, 3-methoxypropionitrile, and examples of sulfur-containing compounds include sulfolane and ethyl. Examples include methyl sulfone and dimethyl sulfoxide.

[Supporting electrolyte]
The supporting electrolyte may be any supporting electrolyte used for electric double layer capacitors, and for example, ammonium salts and phosphonium salts can be used. Examples of ammonium salts include tetrabutylammonium tetrafluoroborate ((C ₄ H ₉ ) ₄ NBF ₄ ), 4-ethylammonium tetrafluoroborate ((C ₂ H ₅ ) ₄ NBF ₄ ), tetrafluoroborate 3 Ethylmethylammonium ((C ₂ H ₅ ) ₃ CH ₃ NBF ₄ ), tetrafluoroboric acid-1,1′-spirobipyrrolidinium ((C ₄ H ₈ ) ₂ NBF ₄ ), hexafluorophosphoric acid 4 Examples include butylammonium ((C ₄ H ₉ ) ₄ NPF ₆ ), 4-ethylammonium hexafluorophosphate ((C ₂ H ₅ ) ₄ NPF ₆ ), and the like. Examples of phosphonium salts include 4-butylphosphonium tetrafluoroborate ((C ₄ H ₉ ) ₄ PBF ₄ ), 4-ethylphosphonium tetrafluoroborate ((C ₂ H ₅ ) ₄ PBF ₄ ), and hexafluorophosphoric acid. Examples thereof include 4-butylphosphonium ((C ₄ H ₉ ) ₄ PPF ₆ ) and 4-ethylphosphonium hexafluorophosphate ((C ₂ H ₅ ) ₄ PPF ₆ ). The amount of the supporting electrolyte to be contained is, for example, 1.0 mol to 2.5 mol with respect to 1 liter of the nonaqueous electrolytic solution.

In the electric double layer capacitor, the following experimental examples and comparative examples were manufactured, and experimental results as shown in FIGS.
[Experimental Example 1]
In the electric double layer capacitor, the active material of the polarizable electrode layers of the positive electrode 10 and the negative electrode 20 is activated carbon made of a phenol resin carbide subjected to esterification using the amino alcohol of Example 1, and propylene as a non-aqueous solvent. Using carbonate, 1.5 mol of triethylmethylammonium tetrafluoroborate (TEMABF ₄ ) was dissolved as a supporting electrolyte in 1 liter of nonaqueous electrolyte.
[Experiment 2]
The same as Experimental Example 1 except that the amino alcohol of Example 2 was used for the esterification treatment of the activated carbon.
[Experiment 3]
The same as Experimental Example 1 except that the amino alcohol of Example 3 was used for the esterification treatment of activated carbon.
[Experimental Example 4]
The same as Experimental Example 1 except that the amino alcohol of Example 4 was used for the esterification treatment of activated carbon.
[Experimental Example 5]
The same as Experimental Example 1 except that the amino alcohol of Example 5 was used for the esterification treatment of activated carbon.
[Experimental Example 6]
Example 1 is the same as Example 1 except that the amino alcohol of Example 6 was used for the esterification treatment of activated carbon.
[Experimental Example 7]
The same as Experimental Example 1, except that the amino alcohol of Example 7 was used for the esterification treatment of the activated carbon.
[Experimental Example 8]
Example 1 is the same as Example 1 except that the amino alcohol of Example 8 was used for the esterification treatment of activated carbon.
[Experimental Example 9]
Example 1 is the same as Example 1 except that the amino alcohol of Example 9 was used for esterification of activated carbon.
[Experimental Example 10]
The same as Experimental Example 1 except that the amino alcohol of Example 10 was used for the esterification treatment of activated carbon.
[Experimental Example 11]
The same as Experimental Example 1 except that the amino alcohol of Example 11 was used for the esterification treatment of the activated carbon.
[Experimental example 12]
Example 1 is the same as Example 1 except that the amino alcohol of Example 12 was used for the esterification treatment of activated carbon.
[Experimental Example 13]
The same as Experimental Example 1 except that the amino alcohol of Example 13 was used for the esterification treatment of activated carbon.
[Experimental Example 14]
Example 1 is the same as Example 1 except that the amino alcohol of Example 14 was used for the esterification treatment of activated carbon.
[Experimental Example 15]
The same as Experimental Example 1 except that the amino alcohol of Example 15 was used for the esterification treatment of the activated carbon.
[Experimental Example 16]
The same as Experimental Example 1 except that the amino alcohol of Example 16 was used for the esterification treatment of the activated carbon.
[Experimental Example 17]
The same as Experimental Example 1 except that the amino alcohol of Example 17 was used for the esterification treatment of activated carbon.
[Experiment 18]
Example 1 is the same as Example 1 except that the amino alcohol of Example 18 was used for the esterification treatment of activated carbon.
[Experimental Example 19]
The same as Experimental Example 1 except that the amino alcohol of Example 19 was used for the esterification treatment of the activated carbon.
[Experiment 20]
The same as Experimental Example 1 except that the amino alcohol of Example 20 was used for the esterification treatment of the activated carbon.
[Experimental example 21]
The same as Experimental Example 1 except that the amino alcohol of Example 21 was used for the esterification treatment of activated carbon.
[Experimental example 22]
The same as Experimental Example 1 except that the amino alcohol of Example 22 was used for the esterification treatment of activated carbon.
[Experimental example 23]
The same as Experimental Example 1 except that the amino alcohol of Example 23 was used for the esterification treatment of activated carbon.
[Experimental Example 24]
The same as Experimental Example 1, except that the amino alcohol of Example 24 was used for the esterification treatment of the activated carbon.
[Experiment 25]
The same as Experimental Example 1 except that the amino alcohol of Example 25 was used for the esterification treatment of the activated carbon.
[Experiment 26]
Example 1 is the same as Example 1 except that the amino alcohol of Example 26 was used for the esterification treatment of activated carbon.
[Experiment 27]
The same as Experimental Example 1 except that the amino alcohol of Example 27 was used for the esterification treatment of the activated carbon.
[Experiment 28]
The same as Experimental Example 1, except that the amino acid of Example 28 was used for the esterification treatment of activated carbon.
[Experimental example 29]
The same as Experimental Example 1 except that the amino acid of Example 29 was used for the esterification treatment of activated carbon.
[Experiment 30]
The same as Experimental Example 1 except that the amino acid of Example 30 was used for the esterification treatment of activated carbon.
[Experimental example 31]
The same as Experimental Example 1 except that the amino acid of Example 31 was used for the esterification treatment of activated carbon.
[Experimental example 32]
The same as Experimental Example 1 except that the amino acid of Example 32 was used for the esterification treatment of activated carbon.
[Experimental Example 33]
The same as Experimental Example 1 except that the amino acid of Example 33 was used for the esterification treatment of activated carbon.
[Experimental example 34]
The same as Experimental Example 1 except that the amino acid of Example 34 was used for the esterification treatment of activated carbon.
[Experimental Example 35]
The same as Experimental Example 1 except that the amino acid of Example 35 was used for the esterification treatment of activated carbon.
[Experimental Example 36]
The same as Experimental Example 1 except that the amino acid of Example 36 was used for the esterification treatment of activated carbon.
[Experiment 37]
The same as Experimental Example 1 except that the amino acid of Example 37 was used for the esterification treatment of activated carbon.
[Experiment 38]
The same as Experimental Example 1 except that the amino acid of Example 38 was used for the esterification treatment of activated carbon.
[Experimental Example 39]
The same as Experimental Example 1 except that the amino acid of Example 39 was used for the esterification treatment of activated carbon.
[Experimental Example 40]
The same as Experimental Example 1, except that the amino acid of Example 40 was used for the esterification treatment of activated carbon.
[Experimental example 41]
The same as Experimental Example 1, except that the amino acid of Example 41 was used for the esterification treatment of activated carbon.
[Experimental Example 42]
The same as Experimental Example 1 except that the amino acid of Example 42 was used for the esterification treatment of activated carbon.
[Experimental example 43]
The same as Experimental Example 1 except that the amino acid of Example 43 was used for the esterification treatment of activated carbon.
[Experimental Example 44]
The same as Experimental Example 1 except that the amino acid of Example 44 was used for the esterification treatment of activated carbon.
[Experimental Example 45]
The same as Experimental Example 1 except that the amino acid of Example 45 was used for the esterification treatment of activated carbon.
[Experimental example 46]
The same as Experimental Example 1 except that the amino acid of Example 46 was used for the esterification treatment of activated carbon.
[Experimental example 47]
The same as Experimental Example 1 except that the amino acid of Example 47 was used for the esterification treatment of activated carbon.
[Experimental Example 48]
The same as Experimental Example 1 except that the amino acid of Example 48 was used for the esterification treatment of activated carbon.
[Example 49]
The same as Experimental Example 1 except that the amino acid of Example 49 was used for the esterification treatment of activated carbon.
[Experimental Example 50]
The same as Experimental Example 1 except that the amino acid of Example 50 was used for the esterification treatment of activated carbon.
[Experimental Example 51]
The same as Experimental Example 1 except that the amino acid of Example 51 was used for the esterification treatment of activated carbon.
[Experimental Example 52]
The same as Experimental Example 1 except that the amino acid of Example 52 was used for the esterification treatment of activated carbon.
[Experimental Example 53]
The same as Experimental Example 1 except that the amino acid of Example 53 was used for the esterification treatment of activated carbon.
[Experimental Example 54]
The same as Experimental Example 1, except that the amino acid of Example 54 was used for the esterification treatment of activated carbon.
[Experimental Example 55]
Example 1 is the same as Example 1 except that the activated carbon is esterified using the amino alcohol of Example 1 and then the activated carbon is esterified using the amino acid of Example 28.
[Experimental Example 56]
Example 1 is the same as Example 1 except that the activated carbon is esterified using the amino alcohol of Example 25 and then the activated carbon is esterified using the amino acid of Example 52.
[Comparative Example 1]
It is the same as Experimental Example 1 except that the activated carbon is not esterified.

  The electric double layer capacitors of Experimental Examples 1 to 18 and Comparative Example 1 are all formed in the same size.

[Evaluation method]
The functional group amounts in FIGS. 12 to 14 are as follows. For Experimental Examples 1 to 56, the Fourier transform infrared spectrophotometer is used for the activated carbon after the esterification treatment and before being dispersed in the solvent to form an electrode slurry. Comparative Example 1 was obtained using a Fourier transform infrared spectrophotometer for activated carbon before being dispersed in the solvent to form an electrode slurry. Also, the initial capacitance and resistance values in FIGS. 12 to 14 are as follows. Each electric double layer capacitor manufactured as described above is left in a 25 ° C. atmosphere for 12 hours, and then the capacitance and resistance in the same atmosphere. A value (in this case, an AC resistance value of 1 kHz is measured) is measured. Moreover, the electrostatic capacity and resistance value after the reliability test in FIGS. 12 to 14 are carried out by performing a reliability test in which a charging voltage of 2.5 V is continuously applied for 500 hours in an atmosphere at 60 ° C. Capacitance and resistance value (here, AC resistance value of 1 kHz is shown) is measured in the atmosphere, and the value obtained by dividing these measurement results by the initial capacitance and resistance value measurement results What is expressed in percentage is the capacity retention rate and the resistance increase rate in FIGS. The thickness before the test after the reliability test of the package 40 shown in FIGS. 12 to 14 is a percentage obtained by dividing the thickness T2 of the film package 40 after the reliability test by the thickness T1 of the initial film package 40. This is shown (see FIGS. 1 and 3).

[Evaluation results]
From the results of Experimental Examples 1 to 54 and Comparative Example 1 in FIGS. 12 to 14, by performing esterification treatment with the amino alcohol of Examples 1 to 27, the carboxyl group on the active material surface decreased, and the amino acids of Examples 28 to 54 It was confirmed that the hydroxyl group on the surface of the active material was reduced by carrying out the esterification treatment with. From Experimental Examples 55 and 56, it was confirmed that the carboxyl group and the hydroxyl group on the surface of the active material were reduced by esterification with amino alcohol and then with amino acid.

  Further, the initial capacitance was slightly larger in Comparative Example 1 in which the active material was not esterified than in Experimental Examples 1 to 56 in which the active material was esterified. In addition, the initial resistance value was slightly smaller in Comparative Example 1 in which the active material was not esterified than in Experimental Examples 1 to 56 in which the active material was esterified. These results indicate that the steric hindrance of the amino group represented by Formula (1) or Formula (2) bonded to the surface of the active material by the esterification treatment is larger than that of the hydroxyl group or carboxyl group, and the non-aqueous electrolyte solution It is presumed that the electrolyte contained therein is caused by the difficulty in getting close to the active material of the polarizable electrode layers 12 and 22 of the positive electrode 10 and the negative electrode 20. In comparison with Experimental Examples 19 to 27 in which the alkyl chain of the amino group becomes longer, the initial capacitances of Experimental Examples 1 to 14 are larger and the initial resistance value is smaller. Yes. In addition, Experimental Examples 55 and 56 had a smaller initial capacitance and a larger initial resistance value than Experimental Examples 1 to 54. From this result, it is clear that the case where both the group represented by the formula (1) and the group represented by the formula (2) are bonded to the surface of the active material is less than when only one of them is bonded. It is presumed that the electrolyte in the water electrolyte is difficult to approach the active material.

  On the other hand, Experimental Examples 1 to 56 in which the active material was subjected to the esterification treatment compared to Comparative Example 1 in which the active material was not subjected to the esterification treatment had lower capacitance and higher resistance after the reliability test. The thickness of the film package 40 due to the reliability test was small. The cause of these results is presumed as follows.

First, by performing charging continuously in the reliability test, a minute amount of water existing in the pores of the active material and in the non-aqueous electrolyte is electrolyzed, and protons are released into the non-aqueous electrolyte. Become. Further, when protons are released into the non-aqueous electrolyte, the protons react with the electrolyte anion component BF ₄ ^{− in the} non-aqueous electrolyte, thereby causing the decomposition of propylene carbonate in the non-aqueous electrolyte, This leads to a decrease in capacitance and an increase in resistance value of the double layer capacitor. In addition, by continuing charging in the reliability test, protons are generated from the hydroxyl groups and carboxyl groups present on the surfaces of the active materials of the polarizable electrode layers 12 and 22 of the electrodes 10 and 20, and the protons and non- The electrolyte anion component BF ₄ ⁻ in the water electrolytic solution reacts to produce the same result as when water is electrolyzed. Furthermore, by continuously performing charging in the reliability test, the hydroxyl groups and carboxyl groups present on the active material surfaces of the polarizable electrode layers 12 and 22 of the electrodes 10 and 20 are desorbed from the active material, and the desorption is performed. As a result, gas is generated in the non-aqueous solvent, which causes the film package 40 to expand.

  On the other hand, in Experimental Examples 1 to 56, the hydroxyl group or carboxyl group on the surface of the active material is substituted with the amino group of formula (1) or formula (2). Since the amino group has a property of coordinating protons, protons generated by electrolysis of moisture in the non-aqueous electrolyte solution and protons generated from hydroxyl groups or carboxyl groups present on the surface of the active material Is captured by the amino group of formula (1) or formula (2) present in Therefore, it is possible to suppress the decomposition of propylene carbonate due to the reaction with protons. For this reason, in Experimental Examples 1 to 56 in which the active material is esterified, the decrease in capacitance and resistance after the reliability test are performed. It is estimated that the increase in value is small.

  In Experimental Examples 1 to 56, since the hydroxyl groups and carboxyl groups present on the surface of the active material are reduced, gas generation due to elimination of the hydroxyl groups and carboxyl groups can be suppressed, and thus the film package It is estimated that the change in the thickness of 40 is small.

  In the present embodiment, the film package type electric double layer capacitor has been described. However, even in the case of an electric double layer capacitor of a type in which a storage element and a non-aqueous electrolyte are sealed in a metal can or other container, Similarly to the electrodes 10 and 20, the active material can be esterified.

  In the present embodiment, the active material of the polarizable electrode layers 12 and 22 of the positive electrode 10 and the negative electrode 20 of the electric double layer capacitor is esterified. However, the polarizable electrode layer of the positive electrode of the lithium ion capacitor is used. The active material constituting the active material or the active material constituting the negative electrode active material layer may be esterified in the same manner as in the above embodiment. The active material constituting the polarizable electrode layer of the positive electrode of the lithium ion capacitor is the same as the active material of the polarizable electrode layers 12 and 22 of the electrodes 10 and 20 of the above embodiment, and the active material of the negative electrode of the lithium ion capacitor. The active material constituting the material layer is polyacene (PAS), various carbon materials, graphite, tin oxide, silicon oxide, etc., and various carbon materials include natural graphite, artificial graphite, coke, non-graphitizable carbon And graphitizable carbon. For this reason, since it is the same as the above embodiment in that a hydroxyl group or a carboxyl group is present on the surface of the active material, by performing esterification treatment on the active material of the positive electrode and the negative electrode of the lithium ion capacitor, The same effect is obtained.

  Moreover, the active material which comprises the active material layer of the negative electrode of a lithium ion secondary battery can also be esterified like the said embodiment. Since the active material constituting the active material layer of the negative electrode of the lithium ion secondary battery is the same as the active material constituting the active material layer of the negative electrode of the lithium ion capacitor, the active material of the negative electrode of the lithium ion secondary battery By performing the esterification treatment, the same effects as those of the above-described embodiment can be obtained.

  Further, in a redox capacitor having an active material layer on the positive electrode and / or the negative electrode, the active material constituting the active material layer can be esterified as in the above embodiment.

  In another electrochemical device having an active material in the positive electrode and / or the negative electrode, the active material can be esterified in the same manner as in the above embodiment.

  The present invention can be widely applied to various electrochemical devices such as an electric double layer capacitor, a lithium ion capacitor, a redox capacitor, a lithium ion secondary battery using a non-aqueous electrolyte and an electrode containing an active material, By the application, the above-described actions and effects can be obtained.

  DESCRIPTION OF SYMBOLS 10 ... Positive electrode, 11 ... Current collector, 12 ... Polarizable electrode layer, 20 ... Negative electrode, 21 ... Current collector, 22 ... Polarizable electrode layer, 30 ... Separator, 40 ... Film package, 50 ... Terminal, B ... Power storage element.

Claims (3)

An electrode for an electrochemical device containing an active material,
An electrode for an electrochemical device, wherein the active material has a group represented by the following formula (1) on the surface thereof.

[Wherein R1 and R2 are alkyl groups having 1 to 3 carbon atoms, and n is an integer of 1 to 5] An electrode for an electrochemical device containing an active material,
An electrode for an electrochemical device, wherein the active material has a group represented by the following formula (2) on the surface thereof.

[Wherein R3 and R4 are alkyl groups having 1 to 3 carbon atoms, and n is an integer of 1 to 5]   An electrochemical device comprising the electrode according to claim 1 and a nonaqueous electrolytic solution.

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