JPS5990365A - Manufacture of electrode for fuel cell or air cell - Google Patents

Abstract

PURPOSE:To provide an electrode for a fuel cell or an air cell which has a high energy density and in which small polarization develops, almost no voltage reduction is caused within the range of large current density and a large current can be obtained by adding an iron phthalocyanine polymer, which is the macromolecular compound of a transition metal complex, as a catalyst for a positive electrode. CONSTITUTION:An electrode current-collector material such as graphite, acetylene black, active carbon or carbon fiber is mixed with an iron compound, urea and at least one compound selected from among pyromellitic dianhydride, pyromellitoamide and pyromellitonitrile. As the above iron compound, a compound reacting with at least one of pyromellitic dianhydride, pyromellitoamide and pyromellitonitrile to produce an ion phthalocyanine polymer, such as ferrous chloride, ferric chloride or ferrous sulfate, is employed. Thus prepared mixture is subjected to reaction under an atmosphere of a nonreactive gas such as argon gas so as to synthesize an iron phthalocyanine polymer supported on the above electrode current-collector material, thereby obtaining an electrode material. In assembling a cell by use of the air electrode of this invention, it is positioned in such a manner that an electrode material layer 1 contacts electrolyte and a porous hydrophobic layer 3 contacts gas. As a result, a three-phase interface consisting of electrolyte, gas and electrode powder is formed in the electrode material layer 1.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is small in size and design, and provides a positive return voltage for a thermal battery or an air battery, which is small in size and makes it possible to obtain an electric current. At the air electrode or oxygen electrode, to prepare the sulfur electrode, the reaction mixture for catalyst synthesis and the electrolyte constituent materials are mixed and heated under a non-reactive gas to synthesize the catalyst and produce the phthalocyanine polymer. The present invention relates to a novel method for manufacturing the above-mentioned polarization, in which the polarization is directly supported on the constituent material at the same time as synthesis.

Conventionally, many proposals have been made regarding catalysts for use in air electrodes or oxygen electrodes for fuel cells and air cells.

That is, as air electrode catalysts or oxygen electrode catalysts for fuel separation, metals such as mesh, silver, gold, platinum, palladium, tungsten bronze, iron or steel phthalocyanine, activated carbon, and nickel oxide doped with lithium are used. Also,
Platinum, palladium,
Prize metals such as ruthenium and silver, alloys of silver and mercury and ruthenium and gold, oxides of transition metals such as manganese and osmium, and NiF”e204 + C0Fe2
The spinel oxides O4+N1CrzO4 and C0A4044 are known.

However, among these catalysts in the prior art,
Prize metals are not economical because they have a high 1lIi value, and other metals are cheap, but air electrodes or oxygen electrodes that use these as catalysts have a higher polarization than precious metals, and large-sized flow-tight IKs. , the electrode characteristics are not sufficiently good, such as a considerable potential drop at the li negative peak, and as a result, fuels incorporating such electrodes cannot be used.
In pond and air batteries, there was a drawback that a fire current could not be obtained.

The present invention was first made in response to the current situation, and
The purpose of this is to use high energy density (W) fuel, air and air ponds with low polarization, almost no potential drop even in the high current density region, and L=T ability to obtain large currents. i
It is to provide water.

To summarize the present invention, in the fuel cell and air annealing electrode of the present invention, the positive electrode contains an iron phthalocyanine polymer, which is a polymeric compound of a transition metal complex, as a catalyst, and the method of containing the iron phthalocyanine polymer is such that it becomes a reactant. The present invention is characterized in that it is mixed with a polar current collector material, synthesized in an atmosphere of a non-reactive gas such as nitrogen gas or argon gas, and simultaneously supported.

Up to now, there has been no example of using an iron 3-thalocyanine polymer by a two-step loading method as a catalyst in an air electrode or an oxygen electrode for a fuel cell or an air battery. According to the present invention, due to the novel structure in which the iron phthalocyanine polymer is contained in the iron phthalocyanine polymer by the above-described simultaneous synthesis method, compared to the conventional iron phthalocyanine monomer or the case where the iron phthalocyanine polymer is incorporated by the conventional method, as will be described later. %ii
It is possible to omit the process of supporting the catalyst to i, and to reduce the produced market polarization, thereby achieving the excellent effect of making it possible to obtain a large current.

The present invention will be explained in detail in (j9).

A fuel cell uses hydrogen gas etc. as a negative electrode active material, and an alkaline solution such as KOH or NaOH, or Na as an electrolyte.
The air battery is constructed using a neutral electrolyte such as C4KCt or an acidic electrolyte such as phosphoric acid, and the air battery uses zinc, aluminum, magnesium, iron, platinum, or an alloy thereof as the negative electrode active material, and the above as the electrolyte. It is constructed using the same material as the fuel used for five ponds.

The electrode in the present invention is used as a regular box for the above-mentioned fuel cells and air cells.

4- The electrode current collector material serving as the main body of the electrode may be any material conventionally used for this type of electrode. For example, one or more carbon substances such as carbon powder, graphite, acetylene black, Ketjenblack EC, activated carbon, carbon fiber, and porous nickel'F!
It can be an electrode plate or the like.

Such '11 is added to Kyokuto Denshi material with one or more iron compounds of pyromellitic dianhydride, pyromellitamide, pyromellinitrile, and urea.

The above-mentioned iron compound may be any compound as long as it reacts with one or more of biromellitic dianhydride, pyromellitamide, and pyromellinitrile to produce an iron phthalocyanine polymer. For example, it can be ferrous chloride, ferric chloride, ferrous sulfate.

The above-mentioned mixture of iron compounds is based on the entire electrode material (
(same below) preferably 0.35 fold tS or more. 0.
If it is less than 35 wt %, the inner cone will have the fifth effect of the present invention, that is, obtain a battery with better performance than the conventional one.

On the other hand, pyromellitic dianhydride, pyromellitamide,
The amount of one or more pyromellinitrile added is preferably 10% by weight or more. This is because if it is less than 10% by weight, it becomes difficult to obtain a good battery.

Urea, which is still one of the reactants, is preferably 0.06 weight φ or more and less than 0.06 weight φ.
As in the case of N-iron compounds and pyromellitic compounds,
1. Enjoy the effects of the present invention. It will be difficult.

A synthetic catalyst such as ammonium molybdate may be added to such a mixture.

Such a mixture is reacted under an atmosphere of a non-reactive gas such as nitrogen or argon gas to form an iron phthalocyanine polymer, which is then combined with the above-mentioned phthalocyanine material to form an electrode material.

The structure and support are preferably carried out by heating at a temperature of 300° C. or higher for up to 40 hours. This is because if the crystallinity is less than 300°C, it takes too much time to synthesize the iron phthalocyanine polymer, while if it exceeds 40 hours, it is economically disadvantageous.

Positive J + (l electrode (d), a mixed powder consisting of a pentode material such as carbon and substances containing the above-mentioned phthalocyanine polymer and a water repellent is molded and pressed together with nickel and a metal mesh such as a trowel, and this is heated - It can be fabricated using LiL.

The reason why the iron phthalocyanine polymer in the present invention is effective as a catalyst is because it is the most efficient four-electron reaction among the electrode reactions of the fE electrode (for example, in an alkaline electrolyte, O
x + 2H2Q+ 4e-→411H-), and also a two-electron reaction (for example, 0 in the alkali Ltm'
2 + N20 +2e--+ OH-+ HO□-
Even when intermediates (like intermediates are produced) are predominant, the intermediates produced (in the case of fl.
When using an alkaline electrolyte; by increasing the decomposition rate of F(02-), the reaction proceeds smoothly in any reaction process. This is considered to be because it is easy. Furthermore, by using the compatible H method at the same time as the synthesis in accordance with the present invention, good contact between the Chichi phthalocyanine polymer and carbon, materials, etc. (The OT performance is reduced), the conductivity is improved, and the flow becomes smoother.

Next, the structure of the official according to the present invention will be explained with reference to the drawings.

That is, FIG. 1 is a schematic cross-sectional view showing one example of the upwardly tilted (air, oxygen or oxygen electrode) structure I@ in the present invention, where ■ is a tunic material and 1-12 is a nickel mesh. , 3 is hydrophobic porosity! It is a surface layer.

When inserting this air electrode into the battery, [a. Other material layer 1]
The substrate is oriented so that the hydrophobic porous layer 3 is in contact with the waste material and the hydrophobic porous layer 3 is in contact with the waste material. This formation forms a three-phase interface of electrolyte, gas, and polar powder in the heavy material 1-1. In addition, the nickel mesh 2 is provided as a support and a support for the electrically conductive material 1 and the hydrophobic porous material 3. The hydrophobic porous pores 3 are made of the same material as the electrode material layer 1 provided on the straight line 11y1 value g108-.
The ratio of the water repellent agent is increased compared to the electrode material layer 1 (or it may be composed of only the water repellent agent, but in this case, it only has a water repellent effect and does not contribute to the reaction) and has a porosity that is similar to that of the electrode material layer 1. do.

Next, the present invention will be explained with reference to Examples, but the present invention is not limited thereto in any way. In the measurements of the current dependence of the electrode potential in the Examples, the potential was measured using a saturated calomel (4□□□ (SCE)'e reference electrode as a reference electrode. Measurements were carried out at room temperature of 20 to 25°C I did it inside.

Example 1 Pyromellinitrile (PN) 4 g, FeC4nH2
Ammonium molybdate (NH) 4 MO? 02
4.4Hz 00.1 g, and carbon powder (200 mesh Jl misfortune) 1 g% Acetylene black (A
B) 3gs Ketjenblack EC 4g of electric iyt ingredients were mixed well in a mortar and placed in a separable flask with N2
The mixture was heated to an atmosphere of 500° C. for 70 hours. After that, 9
- The temperature was raised to 550°C and further heated for 2 hours. The obtained powder was washed by Soxhlet extraction with methanol and pyridine. After drying, 4.5 g of the obtained powder and 2.5 g of Teflon emulsion (containing 60% Teflon) are thoroughly mixed and formed into a sheet using a roll. After drying the sheet in the air for about 30 minutes, place a nickel mesh (50 mm) on one side.
A porous Teflon sheet was placed on top of the mesh and heated at 250°C, 100 kg/cm.
Hot press at pressure 2 for 30 minutes. cooled in air,
An air electrode was prepared by cutting out a circle with a diameter of 30 mm. An air battery is constructed using INKOH as an electrolyte and lead as a negative electrode, and the electrode potential of the air electrode in air (E1
The DC density dependence of 5CEE) was investigated.

For comparison, the same amount of iron phthalocyanine monomer or iron phthalocyanine polymer (
2, s g ) to 1 g of carbon powder and 3 g of acetylene black.
s) Current density dependence of the potential of the air value prepared in the same manner as above from 4.5 g of Ketjenblack IDC mixed powder and 2.5 g of Te10-fluorocarbon emulsion. was also investigated at the same time.

The results are shown in Figure 2. That is, No. 21￥1 is a graph showing the relationship between the current density of the air electrode and the electrode wake level in this example, and A is a graph showing the iron phthalocyanine polymer supported by the new supporting method carried out in this example and shown in 1J. In the case of B
, , C are the cases in which iron phthalocyanine monomer and polymer were combined by conventionally known methods, respectively, and D is the case in which conventionally known silver was used as a catalyst.

According to FIG. 2, when the iron phthalo/anine polymer is supported by the method of simultaneously supporting the synthesis shown in this example, the equilibrium potential is 10,060 V, and 50 mA/am.
10, 270V, 100 mA/c when 2 wires are connected
m'' is energized -0,378V.

As is clear from FIG. 2, compared to the case where iron phthalocyanine monomer and polymer were supported by the conventional method or the case where silver was used as a catalyst, the method of the present invention in which iron phthalocyanine polymer was supported by the method of supporting at the same time as synthesis. In this case, the equilibrium potential is high, the polarization is small, and the potential is stable without a significant drop even in the high current density region.

Example 2 Implementation 1+! I Starting from the same method as in 1, the material and the 'ff1t group-forming hH raw material were thoroughly mixed, and synthesized and supported in a nitrogen atmosphere under the temperature and reaction time conditions shown in Table 1.The resulting powder After the body was washed and dried in the same manner as in Example 1, an air electrode was prepared and the dependence of the electrode position on current density was investigated.

Table 1 The results of the synthesis conditions are shown in Figure 3. That is, FIG. 3 is a graph showing the relationship between the electrode level of the air electrode and the current density in this example, and l]-J in the figure represents the air when synthesized under the conditions shown in Table 1. Indicates the characteristics of the poles.

According to the measurement bundle shown in Fig. 2, the equilibrium potential of the 'electrode is 50 mA/cm2 current, 100
mA/cm2 It can be seen that the respective potentials when energized are as shown in Table 2.

Table 2 Characteristics of each air electrode 13 - As explained above, the starting material and the carbon material constituting the electrode are mixed, and the net electrode (air electrode or ) can simplify the manufacturing process by omitting the step of adding the catalyst externally, and can efficiently support a sufficient amount of catalyst in the constituent materials, and Its characteristics are that polarization is small and there is almost no potential drop even in the high current density region, which provides superior effects compared to conventional ones. Therefore, compared to conventional products, a fuel that incorporates the electrode as a positive electrode can be expected to have much greater practical value.

[Brief explanation of drawings]

FIG. 1 shows a specific example of the structure of a positive electrode (air electrode) manufactured by the method of the present invention.
Figure 3 is a graph showing the relationship between the current density and electrode potential of the 14-air electrode in Examples of the present invention. 1...Electrode material layer 2...Nickel mesh 3...Hydrophobic porous 1-0 Applicant's agent Tadashi Yamamiya Season 1 figure procedural amendment 1. Description of the case 057 Patent Application No. 199987 2 Name of the invention Method for manufacturing electrodes for tuna batteries/air batteries 3 Person making the amendment Relationship to the case Patent applicant Furigana Address 1-1 Uchisaiwai-cho, Chiyoda-ku, Tokyo No. 6 Furigana Name (422) Nippon Telegraph and Telephone Public Corporation 4, Agent 〒102 03-264-3566 5, ゛Date of amendment order Showa 1999 Month, Day 6, Number of inventions increased by amendment 7, Amendment In the subject specification of ``Detailed Description of the Invention,'' page 8, content of amendment MIJIF, as per +11 1 battery electrode on page 3, line 11 and line 13 of the specification, respectively. The manufacturing method is corrected. (2) On page 5, line 10 of the same book, "one or more" is corrected to "one or more". (3) "IO, 35" on page 5, lines 19 and 20 of the same book are corrected to r3.5J, respectively. (4) ro and 06J on page 6, line 9 of the same book are rO
,6J. (5) In the same book, page 7, lines 1 to 5, "The reason is that temperatures of 300°C or higher are disadvantageous."
It is preferable to heat at a temperature of ℃ or higher for 20 hours or more. 30
This is because iron phthalocyanine polymer is difficult to form at a temperature of less than 0°C and less than 20 hours. ” he corrected.

Claims (1)

[Claims] Synthesize an iron phthalocyanine polymer by mixing one or more of pyromellitic dianhydride, pyromellitamide, pyromellinitrile, one or more iron compounds, and urea with the electrode current collector material in a non-reactive raw gas atmosphere. At the same time, it is a good idea to support it on the electric material. A method for producing l+ releasable and vital electrodes for use in batteries.