JP2001203007A - Electrode, its manufacturing method and battery using same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrode and its manufacturing method, which can attain electrochemical oxidization of sugar, and a battery which utilizes chemical energy of sugar as electrical energy. SOLUTION: In interface of an electrode 11 arranged at the face of conductive base substance including Pb and an electrolyte, a complex 13 of an ingredient arranged at the electrode 11 with sugar 12 is formed in a state of a hydroxyl group of the sugar 12 facing the electrode 11. With the movement of electrons from the sugar 12 to the electrode 11 and to an outside circuit via the complex 13, a C-C bond of the sugar 12 is split, and oxidized into oxalic acid, formic acid, CO2 or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to polysaccharides, disaccharides,
The present invention relates to an electrode for electrochemically oxidizing a sugar such as a monosaccharide and a battery using the same.

[0002]

BACKGROUND OF THE INVENTION Sugars, along with proteins and lipids, are important energy sources for animals. For example, typical sugars,
When glucose represented by the chemical formula C ₆ H ₁₂ O ₆ is completely oxidized, 24 electrons are emitted per glucose molecule to generate carbon dioxide gas and water. In the animal body, this 2
Four electrons are used as energy sources. According to thermodynamic calculations, 2872 k per mole of glucose
J has an energy of 4.43 Wh per gram. This is an energy density of 3.8 Wh / g or more of weight energy density of metallic lithium used for a negative electrode of a lithium battery known as a high energy density battery.

[0003]

However, the chemical energy possessed by sugar is used as heat energy by direct combustion in the air or by the action of 12 or more oxidases in the animal body. At present, only a method utilizing chemical energy such as the above has been found (Alberts et al., Essential.
Cell Biology (Garland Pub)
lishing, Inc. ) (1997) p. 107). That is, there is no method for effectively utilizing the chemical energy of the sugar directly as electric energy.

In a conventional aqueous solution system using electrodes,
Since the oxidation reaction of sugar and the electrolysis of water compete, the electrochemical oxidation of sugar could not be performed selectively.

[0005] The present invention solves such a problem, and an electrode capable of efficiently performing electrochemical oxidation of sugar, a method for producing the same, and a battery using chemical energy of sugar directly as electric energy. Is provided.

[0006]

SUMMARY OF THE INVENTION The present invention provides an electrode for electrochemically oxidizing a sugar, wherein the electrode contains at least a component containing Pb on a surface of a conductive substrate.

Here, it is preferable that the conductive substrate is made of Pb metal or Pb alloy.

Preferably, the component containing at least Pb contains at least one compound selected from the group consisting of lead oxide, lead hydroxide, and basic lead carbonate.

Further, the above-mentioned conductive substrate and / or the above-mentioned component containing at least Pb may be composed of Mg, Ti, In,
It is preferable to include at least one metal element selected from the group consisting of Sn and Sb.

[0010] The present invention also provides a method of forming a conductive substrate from a group consisting of lead oxide, lead hydroxide, and basic lead carbonate by electrolyzing the conductive substrate in an alkaline solution using a Pb metal or a Pb alloy. Provided is a method for producing an electrode for electrochemically oxidizing sugar, comprising a step of forming at least one selected compound on the surface of the conductive substrate.

Furthermore, the present invention relates to a battery comprising a positive electrode and a negative electrode provided with an electrolyte therebetween, wherein the negative electrode comprises a saccharide having at least a component containing Pb disposed on the surface of a conductive substrate. Provided is a battery using an electrode for electrochemical oxidation.

Here, it is preferable that the positive electrode is an oxygen electrode for reducing oxygen.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.

In the electrode for electrochemically oxidizing sugar according to the present invention, a component containing at least Pb is disposed on the surface of a conductive substrate.

In this case, since Pb has a high affinity for the hydroxyl group, as shown in FIG. 1, at the interface between the electrode 11 and the electrolyte, the hydroxyl group of the saccharide 12 is directed toward the electrode 11 with the sugar group 12 facing the electrode 11 side. The arranged complex 13 of the component containing at least Pb and the saccharide 12 is formed at a high density, and electrons are transferred from the saccharide 12 to the electrode 11 and the external circuit via the complex 13, whereby the CC of the saccharide 12 is The bond is cleaved, and the sugar 12 is oxidized to oxalic acid, formic acid, CO _{2 and the} like having a small number of carbon atoms.

By the complex formation process via the hydroxyl group of the sugar,
A primary chemical bond is generated between the component containing at least Pb and the hydroxyl group of the sugar, and electrons are transferred from the sugar to the component through the chemical bond. In concert with this, C-
The bond between the C bonds weakens and eventually cleaves. As described above, by undergoing a process of forming a complex via a hydroxyl group bonded to a carbon atom forming a CC bond of a sugar, C-
Since the C bond can be effectively weakened, the C—C bond of the sugar can be electrochemically oxidatively cleaved with lower activation energy. Therefore, since the oxidation potential of the sugar shifts to a lower level, the electrochemical oxidation of the sugar can be performed efficiently.

Here, the term "complex" refers to a complex formed between reactants in a route from a reaction system of a chemical reaction to a production system. In this complex, one or more kinds of ligands are coordinated with one or more kinds of central ions in addition to the active complex located at a high energy level by ordinary chemical reaction. Includes mononuclear or dinuclear complexes that form.

The sugar used herein is not particularly limited, but may be a simple sugar such as glucose, mannose, galactose, fructose, glyceraldehyde, dihydroxyacetone, erythrose, ribulose, xylulose, sedoheptulose, ribose, deoxyribose, sorbose, glucosamine and galactosamine. Examples include saccharides, disaccharides such as isomaltose, maltose, cellobiose, lactose, raffinose and sucrose, oligosaccharides, and polysaccharides such as starch, glycogen, cellulose, glycoprotein, glycosaminoglycan and glycolipid. Among them, glucose, mannose, galactose, and fructose are preferable in that the current efficiency of the electrochemical oxidation reaction in the negative electrode is high. Furthermore, glucose, mannose, and galactose are preferable in terms of current efficiency.

As the conductive substrate, gold, platinum,
Tin, copper, silver, lead, iron, their alloys, metal materials such as stainless steel, conductive polymers such as polyaniline, polythiophene, and polyacetylene; conductive metal oxides such as ITO (indium-tin oxide); Carbon materials such as graphite and natural graphite can be used.

Here, the conductive substrate is made of Pb metal or Pb.
Preferably, it is an alloy. In this case, since a part of the conductive substrate is changed to a lead compound by electrolysis, Pb
Can be easily arranged on the surface of the conductive substrate firmly by chemical bonding. Further, there is an advantage that the composition of the lead compound to be arranged can be freely changed depending on the electrolytic potential and the composition of the electrolytic solution.

As a component containing at least Pb,
Specifically, metallic lead, Pb-Sn, Pb-In, Pb
-Mg, Pb-Ag, Pb- Sb, or lead alloys such as Pb-Sb-Sn, PbO, PbO 2, Pb 3 O 4, PbC
O ₃ , Pb (OH) ₂ , (PbCO ₃ ) ₂ .Pb (O
H) ₂ , PbSO ₄ , PbS, PbF ₂ , PbCl ₂ , Pb
I ₂ , Pb (NO ₃ ) ₂ , PbTiO ₃ , PbZrO ₃ , P
a compound such as b (Ti, Zr) O ₃ .

Here, the component containing at least Pb preferably contains at least one compound selected from the group consisting of lead oxide, lead hydroxide and basic lead carbonate. Lead oxide such as PbO, PbO ₂ , Pb ₃ O ₄ , Pb
Lead hydroxide such as (OH) ₂ , (PbCO ₃ ) ₂ .Pb (O
When a basic lead carbonate such as H) ₂ or a mixture thereof is used, a sugar oxidation reaction can be caused at a potential in a minus region of −0.6 V or less with respect to a Hg / HgO standard electrode.

The above components may be used alone or in combination of two or more. In addition, amino acids such as glycine and alanine, alkyl ammoniums such as tetramethylammonium and tetrabutylammonium, which have a functional group that forms a hydrogen bond through a hydrogen atom of a hydroxyl group, 4-ethylpyridinium, and 2-butylpyridinium Such as alkylpyridiniums, alcohols such as amyl alcohol and glycerin, thiols such as dithiobisalkylamine, thiocyanuric acid and bismuthiol, and at least a primary amino group, a secondary amino group,
A compound having a quaternary amino group, a quaternary amino group, an ammonium group, a pyridinium group, an alcohol group or a thiol group may be used in combination with the above components.

Further, the method for producing an electrode for electrochemically oxidizing a sugar according to the present invention is characterized in that Pb metal or a Pb alloy is used as a conductive substrate, and the conductive substrate is electrolyzed in an alkaline solution. A step of forming at least one compound selected from the group consisting of lead oxide, lead hydroxide, and basic lead carbonate on the surface of the conductive substrate. Thereby, lead oxides such as PbO, PbO ₂ , Pb ₃ O ₄ , Pb
Lead hydroxide such as (OH) ₂ , (PbCO ₃ ) ₂ .Pb (O
H) An electrode in which a basic lead carbonate such as ₂ or a mixture thereof is disposed on a conductive substrate can be easily produced. Using lead or a lead alloy as a working electrode and platinum or the like as a counter electrode, electrolysis is performed in an appropriate potential range of −1.2 V to +0.8 V with respect to the Hg / HgO standard electrode. When the potential is electrolyzed in a positive region near 0.8 V, a lead compound rich in PbO ₂ and Pb ₃ O ₄ can be arranged. When electrolysis is performed in the negative voltage range of −1.2 V to zero volt in the presence of carbon dioxide, a lead compound rich in basic carbonate can be disposed. In addition, a lead compound containing PbF ₂ , PbCl ₂ , PbI ₂ , and PbSO ₄ can be arranged by coexisting iodide, fluoride, chloride, and sulfate ions in the electrolytic solution.

The method of arranging the lead compound is not limited to the above-described electrolysis method in an alkaline electrolyte. After immersing the conductive substrate in a solution in which the lead compound is dissolved, the conductive substrate containing the solution is removed. It can be produced by drying and dissipating the solvent. The electrode thus prepared may be fired in an oxidizing atmosphere. Furthermore, a lead compound is deposited by chemical vapor deposition (C
VD), physical vapor deposition (PVD), sputtering, ion plating, or the like, and may be arranged on the conductive substrate.

The conductive substrate and / or the component containing at least Pb may be composed of Mg, Ti, In, Sn,
And at least one metal element selected from the group consisting of Sb. In this case, the oxidation of the sugar is promoted, so that the oxidation potential of the sugar shifts to a lower level.

Further, the battery according to the present invention is a battery comprising a positive electrode and a negative electrode provided with an electrolyte therebetween, wherein the negative electrode comprises a sugar containing at least a component containing Pb disposed on the surface of a conductive substrate. Is used for electrochemically oxidizing the.

As a result, as shown in FIG.
At the electrolyte interface, a complex 13 of at least a Pb-containing component and the saccharide 12 disposed on the surface of the conductive substrate is formed at a high density with the hydroxyl groups of the saccharide 12 facing the negative electrode 11 side. The transfer of electrons to the negative electrode 11 and the external circuit via the complex 13 cleaves the C—C bond of the saccharide 12, and the saccharide 12 has oxalic acid, formic acid, CO ₂
Is oxidized. As described above, the C—C bond of the saccharide can be effectively weakened by the complex formation process via the hydroxyl group of the saccharide, so that the C—C bond of the saccharide is electrochemically oxidized with lower activation energy. It becomes possible to cleave. Accordingly, since the oxidation potential of the sugar shifts to a lower level, an electromotive force can be obtained between the sugar and the positive electrode, and the chemical energy stored in the sugar molecule in the form of a CC bond is directly used as electric energy. It becomes possible. Cleavage C
It is preferable that the number of -C bonds be large, because the number of electrons involved in the oxidation reaction increases and the amount of available energy increases.

Here, the reaction of the positive electrode is a reduction reaction that occurs at a more noble potential than the oxidation reaction of sugar at the negative electrode, and electrons extracted from sugar molecules are electrochemically applied to the positive electrode via an external load. Any reduction reaction that is acceptable may be used.

The reaction of the positive electrode includes a reduction reaction of water or oxygen, NiOOH, MnOOH, Pb (OH)
₂ , PbO, MnO ₂ , Ag ₂ O, LiCoO ₂ , LiMn
Reduction reaction of hydroxide or oxide such as ₂ O ₄ , LiNiO ₂ , reduction reaction of sulfide such as TiS ₂ , MoS ₂ , FeS, Ag ₂ S, metal halide such as AgI, PbI ₂ , CuCl ₂ A reduction reaction, a reduction reaction of an organic sulfur compound such as a quinone or an organic disulfide compound, a reduction reaction of a conductive polymer such as polyaniline or polythiophene, or the like can be used.

Of these, the positive electrode is preferably an oxygen electrode for reducing oxygen. In this case, since a gas containing oxygen can be used as the positive electrode active material, it is not necessary to hold the positive electrode active material in the battery, so that a battery having a high energy density can be formed.

As the oxygen electrode, any substance capable of reducing oxygen can be used. Such materials include activated carbon, lower manganese oxides such as Mn ₂ O ₃ , platinum, palladium, iridium oxide, platinum ammine complexes,
Cobalt phenylenediamine complexes, metal porphyrins (metals: cobalt, manganese, zinc, magnesium, etc.), and perovskite oxides such as La (Ca) CoO ₃ and La (Sr) MnO ₃ .

As the electrolyte, any electrolyte capable of moving anions and / or cations from the positive electrode to the negative electrode and / or from the negative electrode to the positive electrode and allowing the oxidation and reduction reactions at the positive electrode and the negative electrode to proceed continuously. , Organic substances, inorganic substances, liquids, and solids can be used. These electrolytes include ZnCl ₂ and NH ₄ C in water.
l, alkali metals such as KOH and NaOH, H ₃ P
O _4, obtained by dissolving an acid such as H ₂ SO ₄ and, L in a mixed organic solvent of propylene carbonate and ethylene carbonate
iBF ₄ , an ion exchange membrane made of a polymer material such as a fluororesin having a sulfonic acid group, an amide group, an ammonium group, a pyridinium group, or the like, in which a metal salt such as LiBF ₆ is dissolved, LiBF ₄ , LiCl ₄ , A polymer electrolyte such as polypropylene oxide or polyethylene oxide in which (C ₄ H ₉ ) ₄ NBF ₄ or the like is dissolved can be used.

[0034]

The present invention will be specifically described below with reference to examples.

(Example 1) In Example 1, a plurality of test electrodes having different combinations of a conductive substrate and a component containing Pb were prepared, and the electrolytic oxidation characteristics of sugar were evaluated. The battery was configured as above, and power was generated.

(Preparation of Test Electrode) As a conductive substrate, tin containing 61.9% by weight (wt%) and a thickness of 50 μm was used.
Was cut into a size of 1 × 0.5 cm using a Pb—Sn alloy foil, and a nickel lead wire was joined. Then, the joint portion and the nickel lead were covered with an epoxy resin. The obtained test piece was placed in a 3.1% KOH aqueous solution in a cell shown in FIG.
A test electrode A was produced by performing electrolysis while changing the potential at a potential sweep rate of 20 mV / sec in the range of 2 V to 0 V. The potential increases from −1.2 V toward 0 V, and 0 V
, And a change that decreases toward −1.2 V is defined as one cycle, and five cycles of electrolysis were performed. From the test piece having a metallic luster, a test electrode A having a white deposit disposed on the surface was obtained. This white deposit was confirmed to be a lead compound containing basic lead carbonate and stannate by X-ray photoelectron spectroscopy (hereinafter simply referred to as XPS).

The cell shown in FIG. 2 includes a glass container 21, a rubber stopper 22, a working electrode (negative electrode) 23 composed of a test electrode or a test piece, a platinum counter electrode 24, a Hg / HgO standard electrode 25,
It comprises an electrolytic solution 26 and a positive electrode 27.

Next, a test electrode B was prepared in the same manner as the test electrode A, except that the potential sweep range of the test piece was changed from -1.2 V to +0.8 V. From the test piece having a metallic luster, a test electrode B having a dark brown deposit on the surface was obtained. This deposit is converted to PbO by XPS.
And a lead compound containing stannate.

Next, a test electrode C was prepared in the same manner as the test electrode A, except that a 100 μm thick Pb—Sb alloy foil containing 13 wt% of antimony was used. From the test piece having a metallic luster, a test electrode C having a white deposit disposed on the surface was obtained. This white deposit was confirmed by XPS to be a lead compound containing basic lead carbonate and antimony oxide.

Next, a test electrode D was prepared in the same manner as the test electrode B except that a 100 μm thick Pb—Sb alloy foil containing 13 wt% of antimony was used. From the test piece with a metallic luster, a test electrode D having a dark brown deposit on the surface was obtained. This white deposit is
It was confirmed that it was a lead compound containing PbO and antimony oxide.

Next, a test electrode E was prepared in the same manner as the test electrode A, except that a lead foil having a purity of 99.9% and a thickness of 500 μm was used, and a 6.2% KOH alkaline aqueous solution was used as an electrolyte.
From the test piece having a metallic luster, a test electrode E having a white deposit disposed on the surface was obtained. This white sediment is XP
S confirmed that it was a lead compound containing basic lead carbonate.

Next, a test electrode F was prepared in the same manner as the test electrode B except that a lead foil having a purity of 99.9% and a thickness of 500 μm was used, and a 6.2% KOH alkaline aqueous solution was used as an electrolyte. From the test piece having a metallic luster, a test electrode F having a dark brown deposit on the surface was obtained. This white deposit was confirmed by XPS to be a lead compound containing PbO.

Next, using a chemical vapor deposition apparatus, di-iso-propoxy lead (Pb (OiC ₃ H ₇ ) ₂ ) was used as an evaporation source in one molybdenum boat, and another was used in another molybdenum boat. one of the evaporation source as tetraethoxy tin _{((Sn (OC 2 H 5} ) 4), was further placed tetraethoxy titanium _{(Ti (OC 2 H 5)} 4) as yet another evaporation source to another molybdenum boat. In a reactor downstream of these evaporation sources, a conductive substrate formed by pressure-molding graphite fibers having a size of 1 × 0.5 cm and graphite fibers having a thickness of 0.5 mm and having a Ni lead wire joined thereto was placed at 400 ° C. The evaporation source was heated while flowing argon gas from the upstream to the downstream of the evaporation source, and the thermally decomposed products of lead alkoxide, tin alkoxide, and titanium alkoxide were applied to the surface of the conductive substrate for 5 minutes. After the depositing. Evaporation source cooled,
By flowing an argon gas containing 1 vol% of oxygen for 60 minutes, a test electrode G in which a lead compound containing lead oxide, tin oxide, and titanium oxide was arranged on the surface of the conductive substrate was produced.

Next, a Ni lead wire having a size of 1 ×
After placing a 0.5 cm, 100 μm thick Ni foil in a reactor in which argon gas was replaced, the mixture was heated to 600 ° C. with an infrared lamp. 0.05 mol / l di-iso-propoxy lead,
An ethanol solution in which 0.05 mol / l of tetraethoxytitanium was dissolved was sprayed on a heated Ni foil for 10 minutes, and then an argon gas containing 1 vol% of oxygen was supplied to the reactor. Ni in argon gas containing 1 vol% of oxygen gas
By leaving the foil for 60 minutes, a test electrode H having a lead compound containing lead oxide and titanium oxide disposed on the surface of the Ni foil was obtained.

(Evaluation of Sugar Oxidation Characteristics of Test Electrode) Using the cell shown in FIG.
Alkaline aqueous solution or glucose at 0.02 mol /
Using a dissolved 0.62% KOH alkaline aqueous solution, a test electrode B was used as a working electrode 23, a platinum counter electrode 24, and Hg / H
Electrolysis was performed using the gO standard electrode 25. At room temperature, the potential of the working electrode 23 increases from −1.2 V to +0.8 V in a state where the electrolytic solution 26 is allowed to stand, and decreases to −1.2 V when it reaches +0.8 V. This change was defined as one cycle, and 20 cycles of electrolysis were performed. FIG. 3 shows the current-potential characteristics at the 20th cycle.

In the electrolyte containing glucose, the oxidation current around minus 0.4 V accompanying the dissolution of the lead alloy was smaller than in the electrolyte not containing glucose, and the dissolution of the lead alloy was suppressed. Also, the oxidation current peak due to the oxidation of glucose was −1.0 V, −0.8 V,
It appeared near minus 0.6V. After the electrolysis, when the electrolytic solution containing glucose was analyzed using liquid chromatography, an oxidation product of glucose, gluconic acid,
Oxalic acid and formic acid were detected. When the same property evaluation was performed for the test electrode A and the test electrodes C to H, the result showing the oxidation of the sugar was obtained as in the case of the test electrode B. Further, instead of glucose, galactose which is a monosaccharide,
Mannose, sorbose, fructose, the disaccharides maltose, sucrose, lactose, raffinose,
When the characteristics of the test electrodes A to H were evaluated using starch, which is a polysaccharide, the results showing the oxidation of sugar were obtained as in the case of glucose. Therefore, electrochemical oxidation of sugar using the test electrode of this example could be confirmed.

FIG. 4 shows that glucose was 0.02 mol / l.
The redox current-potential response of the test electrode B of this example in a dissolved 0.62% KOH aqueous solution, and the redox current-potential response of an oxygen electrode composed of activated carbon and a manganese lower oxide. The oxygen electrode applied a reduction current by reduction of oxygen in a potential region in the negative direction from around plus 0.1 V. The test electrode B of this example applied an oxidation current due to oxidation of glucose from about -1 V to about -0.4 V. Therefore, it was found that a battery having an electromotive force of 1 V to 0.4 V can be formed by combining the above-described oxygen electrode as a positive electrode and the test electrode of this example as a negative electrode.

Next, using the cell shown in FIG. 2, a 0.31% KOH alkaline aqueous solution or 0.31% KO in which 0.5 mol / l of glucose was dissolved was used as the electrolytic solution 26.
Electrolysis was carried out using an H alkaline aqueous solution, a test electrode A as a working electrode 23, a platinum counter electrode 24, and a Hg / HgO standard electrode 25. At room temperature, a constant current of 2 mA is applied to the working electrode 23 in the oxidation direction for 120 while stirring the electrolytic solution 26.
It passed for 0 second, and the time-potential characteristic at that time was evaluated. FIG. 5 shows the obtained time-potential characteristics.

In an electrolytic solution containing glucose, electrolysis 12
Even after 00 seconds, the potential of the working electrode 23 remains minus 58.
Given a constant value of 0 mV, it was found that glucose was continuously oxidized. On the other hand, in an electrolyte solution containing no glucose, at about 300 seconds after electrolysis, the potential of the working electrode 23 changes from about −610 mV, which indicates the oxidative dissolution of the lead alloy, to about 400 mV at which the generation of a higher oxide of the lead alloy occurs.
Moved to near V.

When the same characteristics were evaluated for the test electrodes B to H, a result showing continuous oxidation of sugar was obtained in the electrolytic solution containing glucose as in the case of the test electrode A. The potential of the test electrode in each electrolytic solution after 1200 seconds of electrolysis is shown in (Table 1).

[0051]

[Table 1]

The characteristics of the test electrodes A to H were evaluated using the monosaccharides galactose, mannose, sorbose, fructose, the disaccharides maltose, sucrose, lactose, raffinose, and the polysaccharide starch. As in the case of glucose, a result showing continuous oxidation of sugar was obtained. Pb-Sn on the conductive substrate,
Test electrodes A to D using a lead alloy such as Pb-Sb, in which alloy components are mixed in a component containing Pb, and test electrodes in which tin oxide and titanium oxide are mixed in a component containing Pb. G and H are test electrodes E using lead for the conductive substrate.
Electrolysis in an electrolyte solution containing glucose compared to E and F
The potential after 200 seconds showed a more negative oxidation potential, indicating that the oxidation of the sugar was promoted by the alloy component and the added metal element.

As the alloy component and the additive metal element having the effect of promoting the electrolytic oxidation of sugar, in addition to tin (Sn), antimony (Sb) and titanium (Ti) used in Examples, indium (In) was used. And magnesium (Mg) are effective.

(Evaluation of Battery Characteristics) Using the cell shown in FIG. 2, a 0.62% aqueous KOH solution or 0.5 mol / l of glucose was dissolved as an electrolytic solution 26.
Using a 62% KOH alkaline aqueous solution, a test cell A was used as the negative electrode 23, and a 3 cm diameter oxygen electrode made of activated carbon and manganese lower oxide was used as the positive electrode 27 to form a battery cell.
The battery characteristics were evaluated.

The battery cell was discharged at a constant current of 0.2 to 50 mA for 20 seconds while stirring the electrolytic solution 26 at room temperature.
FIG. 6 shows the current-voltage characteristics obtained at that time.

For the test electrodes A to H, at room temperature,
While stirring the electrolytic solution 26 at a constant current of 1 mA for 1 hour,
The voltages when the battery cells were discharged are summarized in (Table 2).

[0057]

[Table 2]

As is clear from the current-voltage characteristics of FIG. 6 and the results of the continuous discharge test shown in (Table 2), the battery using the test electrode of this example as a negative electrode utilizes the oxidation reaction of sugar. Could extract electrical energy.

In addition, in place of glucose, the characteristics of test electrodes A to H were evaluated using monosaccharides such as galactose, mannose, sorbose, fructose, disaccharides such as maltose, sucrose, lactose, raffinose, and polysaccharides such as starch. As a result, it was confirmed that the battery operated as in the case of glucose.

(Example 2) In Example 2, a Pb alloy was used as a conductive substrate, and a component containing Pb disposed on the surface thereof and a functional group forming a hydrogen bond via a hydrogen atom of a hydroxyl group were used. Thiocyanuric acid (s-triazine-2,4,6-trithiol) (hereinafter referred to as TCA) or 2,2'-dithiobisethanamine (hereinafter referred to as CYST) Test electrodes were prepared, the electrolytic oxidation characteristics of sugar were evaluated, and a battery having these test electrodes as a negative electrode was configured to generate power.

(Preparation of Test Electrode) TCA was adjusted to 0.05 mo.
1 / l dissolved ethanol solution (A) and CYST at 0.
An ethanol solution (B) in which 01 mol / l was dissolved was prepared. The test electrode A of Example 1 was immersed in the solution (A) or the solution (B), air-dried, and the surface was modified with TCA molecules or CYST molecules.
Was prepared.

(Evaluation of Sugar Oxidation Characteristics of Test Electrode) Using the cell shown in FIG.
0.5 mol / l of alkaline aqueous solution or glucose
Using a dissolved 0.31% KOH alkaline aqueous solution, a test electrode I or J was used as a working electrode 23, and a platinum counter electrode 24,
Electrolysis was performed using the Hg / HgO standard electrode 25. While stirring the electrolytic solution 26 at room temperature, a constant current of 2 mA was passed to the working electrode 23 in the oxidation direction for 1200 seconds, and the time-potential characteristics at that time were evaluated. The potential of the test electrode in each electrolytic solution after 1200 seconds of electrolysis is shown in (Table 3).

[0063]

[Table 3]

In an electrolytic solution containing glucose, electrolysis 12
Even after 00 seconds, the potential of the working electrode 23 remains minus 62.
Giving a value from 0 mV to minus 610 mV, it was found that glucose was continuously oxidized. On the other hand, in the electrolytic solution containing no glucose, the potential of the working electrode 23 shifted to around +400 mV at which the generation of a higher oxide of lead occurred around 600 seconds after the electrolysis.

The test electrodes I and J were characterized using monosaccharides such as galactose, mannose, sorbose, fructose, disaccharides such as maltose, sucrose, lactose, raffinose and polysaccharides instead of glucose. However, results indicating continuous oxidation of saccharides were obtained. Therefore, continuous oxidation of sugar using the test electrode of this example could be confirmed.

(Evaluation of Battery Characteristics) Using the cell shown in FIG. 2, a 3.1% KOH alkaline aqueous solution or a 3.1% KOH alkaline aqueous solution in which 0.5 mol / l fructose was dissolved was used as the electrolytic solution 26. , The test electrode I or J was used as the negative electrode 23, and the same oxygen electrode as in Example 1 was used as the positive electrode 27.
And the battery characteristics were evaluated.

While stirring the electrolytic solution 26 at room temperature, 1 mA
(Table 4) collectively shows the voltage when the battery cell was discharged at the constant current for 1 hour.

[0068]

[Table 4]

As is clear from the results of the continuous discharge test shown in Table 4, the battery of this example was able to extract electric energy by utilizing the oxidation reaction of sugar.

In addition, instead of fructose, glucose, galactose, mannose and sorbose which are monosaccharides, maltose, sucrose, lactose, raffinose which are disaccharides and starch which is a polysaccharide were used to evaluate characteristics of test electrodes I and J. As a result, it was confirmed that the battery operated as in the case of fructose.

(Embodiment 3) Using the cell shown in FIG.
Instead of an oxygen electrode, a manganese dioxide positive electrode (MnO ₂ ) used for a manganese dry battery, a nickel positive electrode (NiOOH) used for a nickel-metal hydride storage battery, a lead positive electrode (PbO ₂ ) used for a lead storage battery, or Cobalt acid positive electrode (LiCoO) used in lithium ion batteries
₂ ) was used as the positive electrode 27, and the test electrode A of Example 1 was used.
A battery having G or H as the negative electrode 23 was constructed. The electrolytic solution contains 0.1 mol / l of mannose (monosaccharide), raffinose (disaccharide), or starch (polysaccharide), an aqueous solution of ZnCl _{2, an} aqueous solution of KOH, an aqueous solution of H ₂ SO ₄ , or PC-EC-Gly. Using LiPF ₆
The battery characteristics were evaluated.

In Tables 5, 6 and 7, 1 mA was used.
Are collectively shown when the battery is discharged at a constant current for one hour. In ZnCl ₂ aqueous solution an aqueous solution containing a saturating concentration of a ZnCl ₂ 30 wt% and ZnO used here, KO
H aqueous solution is an aqueous solution containing 6.2% by weight of KOH, and H ₂ S
The O ₄ aqueous solution is an aqueous solution containing 18% by weight of H ₂ SO ₄
-EC-Gly-LiPF ₆ is a mixed solvent containing propylene carbonate (PC), ethylene carbonate (EC) and glycerin (Gly) in a volume ratio of 1: 1: 0.5.
the iPF ₆ is obtained by dissolving 1.2mol / l.

[0073]

[Table 5]

[0074]

[Table 6]

[0075]

[Table 7]

As is clear from Tables 5 to 7,
The battery of the present invention was able to extract electric energy by utilizing the oxidation reaction of sugar.

[0077]

According to the present invention, there is provided an electrode for oxidizing sugar electrochemically, in which a component containing at least Pb is disposed on the surface of a conductive substrate, a method for producing the electrode, and a battery using the electrode as a negative electrode. I do. According to the electrode of the present invention, the electrochemical oxidation of sugar can be efficiently performed. Further, according to the battery of the present invention, the chemical energy of the sugar can be effectively used directly as electric energy.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing the electrochemical oxidation process of sugar in one embodiment of the present invention.

FIG. 2 is a cross-sectional view of a cell used for preparation of a test electrode, evaluation of sugar oxidation characteristics, and evaluation of battery characteristics in one example of the present invention.

FIG. 3 is a current-potential characteristic diagram of a test electrode according to one embodiment of the present invention.

FIG. 4 is a graph showing oxidation-reduction current-potential characteristics of a test electrode and an oxygen electrode in the example.

FIG. 5 is a time-potential characteristic diagram of a test electrode in the example.

FIG. 6 is a current-voltage characteristic diagram of the battery in the example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Electrode (negative electrode) 12 Sugar 13 Complex 21 Glass container 22 Rubber stopper 23 Working electrode (negative electrode) 24 Platinum counter electrode 25 Hg / HgO standard electrode 26 Electrolyte 27 Positive electrode

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01M 4/60 H01M 4/60 4/86 4/86 Z F Term (Reference) 4K011 AA65 AA69 DA10 4K021 AB25 AC09 BA06 DA13 DC15 5H018 AA03 AS03 EE02 EE03 EE10 EE12 5H032 AA00 AS09 BB10 CC11 EE01 EE04 5H050 AA00 BA04 CA12 CB19 EA12

Claims (7)

[Claims] 1. An electrode for electrochemically oxidizing sugar, wherein at least a component containing Pb is disposed on a surface of a conductive substrate. 2. The electrode according to claim 1, wherein the conductive substrate is Pb metal or Pb alloy. 3. A component containing at least Pb, wherein the component comprises lead oxide,
3. The electrode according to claim 1, comprising at least one compound selected from the group consisting of lead hydroxide and basic lead carbonate. 4. A conductive substrate and / or at least P
b, the components containing Mg, Ti, In, Sn, and Sb
The electrode according to any one of claims 1 to 3, comprising at least one metal element selected from the group consisting of: 5. A method comprising using a Pb metal or a Pb alloy as a conductive substrate and electrolyzing the conductive substrate in an alkaline solution to obtain at least one selected from the group consisting of lead oxide, lead hydroxide, and basic lead carbonate. Forming a compound on the surface of the conductive substrate.
A method for producing an electrode according to claim 1. 6. A battery comprising a positive electrode and a negative electrode provided via an electrolyte as constituent elements, wherein the negative electrode is used as the negative electrode.
A battery using the electrode according to any one of claims 4 to 4. 7. The battery according to claim 6, wherein the positive electrode is an oxygen electrode for reducing oxygen.