JP2859531B2 - Fuel cell electrode and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel cell electrode and a method for producing the same, and more particularly to a catalyst layer for a fuel cell electrode such as a phosphoric acid fuel cell and a method for producing the same.

[0002]

2. Description of the Related Art In a fuel cell such as a phosphoric acid fuel cell, for example, a pair of fuel electrode and air electrode are provided on both sides of a matrix impregnated with an electrolyte, and a pair of fuel flow path and air flow path are further provided outside the electrode. It is formed by laminating a plurality of unit cells each having a porous carbon plate provided with ribs for electrolyte storage with a separator interposed therebetween. In addition, components such as a fuel electrode and an air electrode, a matrix, and a porous carbon plate with a rib for storing electrolyte are impregnated with an electrolyte such as phosphoric acid so that an electrochemical reaction easily occurs.

Hereinafter, a conventional fuel cell will be described by taking a phosphoric acid type fuel cell as an example. For the practical use of phosphoric acid fuel cells, it is important to (a) significantly reduce costs and (b) improve reliability. In order to greatly reduce the cost, for example, by improving the output density, in other words, by improving the cell voltage-current density characteristics so that the cell voltage becomes higher when the current density is increased, the number of stacked cells is increased. Needs to be reduced. Further, in order to improve the reliability of the fuel cell, for example, it is necessary to improve the electrode structure to improve the long-term life characteristics of the cell. The cell voltage of the phosphoric acid fuel cell is practically represented by equation (1).

[0004] [Equation _{1] E = Eo- △ E H2} - △ Eo 2 -IR ( cell _{voltage) ···· (1) △ H 2} -E H2 - E (H 2 Gain) ... (2 _{) △ Ho 2 = Eo 2 -} E (O 2 gain) ... (3)

Here, E is a cell voltage when fuel is supplied to the fuel electrode and air is supplied to the air electrode, Eo is a cell voltage when H ₂ is supplied to the fuel electrode, O ₂ is supplied to the air electrode, and E _H2 is a fuel voltage. The cell voltage when H ₂ is supplied to the pole and air is supplied to the air electrode, Eo ₂ is the cell voltage when fuel is supplied to the fuel electrode, and the cell voltage when O ₂ is supplied to the air electrode, I is the current density, and R is the cell internal resistance (unit) △ H _H2 is an H ₂ gain (an index indicating the gas diffusivity of the fuel electrode, the smaller the better, the better the diffusivity), and △ Eo ₂ is O ₂
The gain (an index indicating the gas diffusivity of the air electrode, and the smaller the gas diffusivity, the better the diffusivity) and IR are the voltage drop (product of the current density and the internal resistance of the cell) due to the internal resistance of the cell.

In equation (1), as Eo increases, ΔE
_H2, the cell voltage E, the higher △ Eo _2, IR is small. Conventionally, in order to increase Eo, the amount of platinum per unit area of the electrode catalyst layer has been increased,
Further, in order to reduce the voltage drop IR due to the H ₂ gain △ E _H2 , the O ₂ gain や Eo ₂ and the internal resistance of the cell, the thickness of the electrode catalyst layer is reduced.

FIG. 45 is an explanatory view showing the structure of a conventional electrode catalyst layer disclosed in, for example, JP-A-3-37963. In the figure, the thickness L [μm] of the electrode catalyst layer obtained by binding the catalyst carrying platinum on the carbon black carrier and the amount of platinum D [mg / cm ² ] are represented by rectangular coordinates (D, L). At this time, the electrode catalyst layer is configured to be in a region that simultaneously satisfies the following expressions (4), (5), and (6).

[0008]

(Equation 2)

However, the composition of the catalyst powder is only platinum and carbon black carrier, and no consideration has been given to the content of metal elements other than platinum.

[0010]

In the above-mentioned electrode catalyst layer of a phosphoric acid fuel cell or the like, the electrode catalyst layer becomes too dense and the electric resistance is low, but the gas diffusion property is poor and the cell voltage - current density is low. And the number of stacked cells cannot be reduced.
Increased after time reduction of the cell voltage, there is a problem that can not be improved in reliability. In addition, since the electrode catalyst layer is too dense, there is a problem that the electrode catalyst layer is not quickly impregnated with an electrolyte such as phosphoric acid. Further, when containing a metal element except platinum in the catalyst powder, the electrical resistivity and electric resistivity of the volume ratio of carbon black responsible <br/> body is a conductive material of the electrode catalyst layer is smaller becomes the electrode catalyst layer There was a problem that it might become large.

[0011] This invention has been made to solve the above problems, the cell voltage - current density characteristics is high and, after the time of cell voltage reduction is small, good fuel cell of long life characteristics It is intended to obtain an electrode for use. It is another object of the present invention to obtain an electrode catalyst layer in which the impregnation of an electrolyte such as phosphoric acid is promptly performed and the electric resistance value is appropriate. Another object of the present invention is to obtain a low-cost and highly reliable electrode for a fuel cell and a method for manufacturing the same.

[0012]

According to the first aspect of the present invention, there is provided a matrix impregnated with an electrolyte, a pair of fuel and air electrodes provided on both sides of the matrix, and In a fuel cell electrode formed by laminating a plurality of unit cells each comprising a pair of fuel flow paths and an air flow path formed outside the electrode with a separator interposed therebetween, the fuel electrode and the air electrode At least one of the electrode catalyst layers is composed of a catalyst powder in which a carbon black carrier carries platinum and ash, which is one or more metal elements other than platinum, and a fluororesin. 10% to 2 with respect to the catalyst layer
5%.

In the invention according to claim 2 of the present invention, the porosity of the electrode catalyst layer is 50% to 80%.

According to a third aspect of the present invention, the content of the fluororesin in the electrode catalyst layer is 20% to 60%.

According to a fourth aspect of the present invention, the platinum content in the catalyst powder is 10% to 40%.

The invention according to claim 5 of the present invention is one wherein the ash content in the catalyst powder is 15% or less.

In the invention according to claim 6 of the present invention, the porosity of the electrode catalyst layer is 20% to 45%.

According to a seventh aspect of the present invention, the carbon black carrier is heat-treated carbon having a density of 1.8 g / cm ³ or more.

In the invention according to claim 8 of the present invention, the thickness of the electrode catalyst layer of the air electrode is set to 100 μm to 350 μm.

According to a ninth aspect of the present invention, the thickness of the electrode catalyst layer of the fuel electrode is set to 50 μm to 250 μm.

According to a tenth aspect of the present invention,
An electrode catalyst layer comprising a catalyst powder in which platinum and ash, which is one or more metal elements other than platinum, is supported on a carbon black carrier and a fluororesin, is subjected to a temperature in the range of 50 ° C to 300 ° C and a pressure of 10 kgf / cm ² to The method includes a step of press-molding at a pressure in the range of 50 kgf / cm ² .

The invention according to claim 11 of the present invention provides
Was immersed an electrode catalyst layer before press-forming organic Solvent, then those containing a step of extracting and removing the organic material of the electrode catalyst layer while applying ultrasonic vibration of the electrode catalyst layer.

[0023]

According to the first aspect of the present invention, the sum of the voltage drop of the electrode catalyst layer of the air electrode and the O ₂ gain of the cell is reduced by setting the volume ratio of the carbon black carrier within a predetermined range. And increase the cell voltage.

In the second aspect of the present invention, by setting the porosity of the electrode catalyst layer within a predetermined range, the voltage drop due to electric resistance , the H ₂ gain, and the O ₂ gain are reduced.
And increase the cell voltage.

In the third aspect of the present invention, the sum of the voltage drop due to electric resistance and the O ₂ gain is reduced by setting the fluorine resin content of the electrode catalyst layer within a predetermined range, and the cell voltage is increased. I do.

According to a fourth aspect of the present invention, by setting the platinum content in the catalyst powder within a predetermined range, the sum of the voltage drop due to electric resistance and the O ₂ gain is reduced, and the cell voltage is increased. .

In the fifth aspect of the present invention, the electric resistivity and electric resistance of the electrode catalyst layer are reduced by setting the ash content in the catalyst powder to a predetermined range or less.

In the sixth aspect of the present invention, the cell voltage is increased by setting the porosity of the electrode catalyst layer within a predetermined range.

In the seventh aspect of the present invention, since the density of the carbon black carrier is set within a predetermined range and the carbon carrier is heat-treated, the aging characteristics of the cell voltage and the O ₂ gain are improved.

In the eighth aspect of the present invention, by setting the thickness of the air electrode in a predetermined range, the sum of the voltage drop due to electric resistance and the O ₂ gain is reduced, and the cell voltage is increased.

In the ninth aspect of the present invention, the sum of the voltage drop due to the electric resistance and the H ₂ gain is reduced by setting the thickness of the fuel electrode within a predetermined range, and the cell voltage is increased.

According to a tenth aspect of the present invention, the electric resistivity of the electrode catalyst layer is reduced.

In the eleventh aspect of the present invention, the electric resistivity of the electrode catalyst layer is reduced.

[0034]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A fuel cell electrode according to the present invention comprises a matrix impregnated with an electrolyte, a pair of fuel and air electrodes provided on both sides of the matrix, and a pair of electrodes formed outside these electrodes. In a fuel cell electrode formed by laminating a plurality of unit cells each composed of a fuel flow path and an air flow path with a separator interposed therebetween, at least one electrode catalyst layer of the fuel electrode and the air electrode is formed of carbon. It is composed of a catalyst powder in which a black carrier carries platinum and ash, which is one or more metal elements other than platinum, and a fluororesin.

The volume ratio of the carbon black carrier is as follows:
It is 10% to 25% (more preferably 15% to 20%) with respect to the electrode catalyst layer. Thus, it distributed proper of the composition of the electrode catalyst layer, the cell voltage - current density characteristics is high and a good fuel cell small extended life characteristics decline when after the cell voltage is obtained. The electrode catalyst layer in the present invention comprises platinum, ash, a heat-treated carbon black carrier, a fluororesin, and pores. Here, considering the unit volume of the electrode catalyst layer, the volume of the electrode catalyst layer is the volume of platinum plus the volume of platinum.
Ash volume + heat-treated carbon black carrier volume + fluororesin + pore volume.

Hereinafter, it is defined as follows. The volume ratio of the heat-treated carbon black carrier volume × 100 [%] of the volume / electrode catalyst layer of the heat treatment of carbon black in charge <br/> body (before the electrolyte impregnation) the porosity of the electrode catalyst layer of the (electrode catalyst layer Volume of pores (before electrolyte impregnation) / Volume of electrocatalyst layer × 100
[%], The electrolyte occupancy of the electrode catalyst layer is the volume of the electrolyte (in the electrode catalyst layer) / the volume of the pores (before the electrolyte impregnation of the electrode catalyst layer) × 100 [%], the electrode (after the electrolyte impregnation) The porosity of the catalyst layer is expressed as porosity (of the electrode catalyst layer) / 100 × (10
0- (electrolyte occupancy of the electrode catalyst layer) [%].

The unit weight of the electrode catalyst layer and the catalyst powder is
Considering the weight of the electrode catalyst layer, the weight of platinum + weight of ash + heat treatment
Natural carbon blackResponsibleBody weight + fluororesin weight, touch
The weight of the medium powder is platinum weight + ash weight + heat treated carbo
BlackResponsibleBody weight, fluororesin content is fluororesin
Weight / electrode catalyst layer weight × 100 [%], platinumconcentration
(platinumContent) Is weight of platinum / weight of catalyst powder × 100
[%], Ash content is weight of ash / weight of catalyst powder × 1
Defined as 00 [%].

The fluororesin of the electrode catalyst layer in the present invention comprises at least one of polytetrafluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-perfluoroalkylvinyl ether copolymer and the like. It is.
The ash of the electrode catalyst layer in the present invention is made of at least one metal among nickel, chromium, iron, cobalt, copper , ruthenium, palladium and the like.

In the present invention, the volume ratio of the heat-treated carbon carrier in the electrode catalyst layer is 10 to 25% (preferably 1%).
5-20 [%]) and the porosity of the electrode catalyst layer is 50-80 [%] (preferably 60-70 [%]).
[%]), Fluorine resin containing Yuritsu 20-60 [%] (preferably 30 to 50 [%]), 10 to 40 platinum concentration
[%] (Preferably 15 to 30 [%]), the ash content of 15%] (preferably 10 [%]) or less, heat-treated carbon black responsible body density 1.8 [g / cm ^3] or more Carbon, having a porosity of 20 to 45% (preferably 25 to 40%)
[%]), The thickness of the air electrode catalyst layer is 100 to 350 [μ
m] (preferably 150 to 300 μm), and the thickness of the anode catalyst layer is set to 50 to 250 μm (preferably 100 to 300 μm).
200 [μm]). Thus, the cell voltage - current density characteristics and makes it possible to increase the over-time characteristics of the cell voltage, impregnation of an electrolyte such as phosphoric acid to the electrode catalyst layer is quickly.

Further, the method for producing an electrode catalyst layer of the present invention comprises:
The temperature of the electrode catalyst layer is 50 to 300 [° C.] and the pressure is 10 to 50.
And press-molded at [kgf / cm ^2], then immersed in an organic solvent medium such as acetone before the heat treatment, then, since to include the step of extracting and removing organic matter while applying ultrasonic vibration, the electrode catalyst layer electrically It is possible to provide a low-cost, highly-reliable fuel cell with low resistivity.

Hereinafter, the present invention will be described in more detail with reference to Examples 1 to 14 and Comparative Examples. Embodiment 1 FIG. First, a dispersion of catalyst powder and polytetrafluoroethylene (hereinafter abbreviated as PTFE), which is a fluororesin, was prepared to form an electrode catalyst layer for an air electrode in a fuel cell. The catalyst powder contains 20% platinum by weight,
Carbon black responsible body (hereinafter, referred to as carbon responsible body) is 72 [%], ash mainly comprising nickel was used for 8%. Also, PTFE dispersion is
The PTFE having a solid content of PTFE of 60%, the dispersant of 4%, and the balance being water was used. Carbon platinum catalyst powder are responsible lifting was used graphitized carbon in charge of body 2500 Density 1.8 was subjected to heat treatment of ^{[℃] [g / cm 3} ] ( hereinafter referred to as heat treatment Carbon) . An aqueous catalyst paste was prepared using the catalyst powder and PTFE. After the catalyst paste was thinly formed into a film, the water was removed by drying to obtain an electrode catalyst layer. Furthermore, this electrode catalyst layer was immersed in acetone subjected to ultrasonic vibration for 20 hours (hereinafter simply referred to as [h]) to extract and remove most of organic substances such as a dispersant in the electrode catalyst layer and dried. Thereafter, the resultant was finally fired at a temperature of 360 [° C.], and thereafter, was subjected to press molding at a room temperature of about 20 [° C.].

According to this method, the catalyst powder / PTFE in a weight ratio of
= 60/40, and an electrode catalyst layer of an air electrode having a weight (basis weight) of 15.0 [mg / cm ² ] of the electrode catalyst layer per unit area was produced. In the same way, platinum 10%] by weight, the catalyst powder and PT of the carbon responsible body (heat treatment Carbon) 90 [%]
Using FE, catalyst powder / PTFE = 60/4 by weight ratio
A catalyst layer of a fuel electrode having a basic weight of 6.0 [mg / cm ² ] and a porosity of 65 [%] was prepared. When forming the electrode catalyst layer of the air electrode, the pressing pressure P is changed to change the carbon in the electrode catalyst layer.
Changing the volume ratio C of the responsible body was measured porosity ε and thickness L in this case the electrode catalyst layer. The results are shown in FIG. 1 and FIG. Further, the electric resistivity ρ and the electric resistance Rc of the electrode catalyst layer were measured. The result is shown in FIG.

[0043] According to FIG. 1, the volume ratio C of the carbon in charge of the electrode catalyst layer is changed by the magnitude of the pressing pressure P. Volume ratio C of the larger pressing pressure P carbon responsible body also increases. Furthermore, as the volume ratio C of the carbon in charge of the electrode catalyst layer is increased according to Fig. 2,
The porosity ε and the thickness L of the electrode catalyst layer are small.
The thickness L of the electrode catalyst layer is preferably smaller in terms of compactness of the cell, the volume ratio C of the carbon responsible body 10
で 15% or more tends to be saturated.

[0044] According similarly to FIG. 3, as the volume ratio C of the carbon in charge of the electrode catalyst layer increases, the electrical resistivity of the electrode catalyst layer ρ and electric resistance Rc is reduced. In order to make the current distribution inside the cell uniform and to reduce the Joule loss, it is desirable that the electric resistivity ρ is small, and in order to reduce the above-mentioned voltage drop IR due to the cell internal resistance R, the electric resistance Rc is smaller is desirable, there is a tendency that the volume ratio C of the carbon responsible body is saturated at 10 to 15 [%] or more. Above, the volume ratio C of the carbon responsible <br/> of the electrode catalyst layer 10 [%] (preferably 15 [%])
By controlling the thickness in the above range, the thickness L, the electric resistivity ρ, and the electric resistance Rc of the electrode catalyst layer can be appropriately adjusted.

Next, carbon paper was bonded to the electrode catalyst layers of the fuel electrode and the air electrode, and assembled into cells as the electrodes of the fuel electrode and the air electrode, respectively. The electrodes of the fuel electrode and the air electrode on both sides of a matrix having a thickness of 100 [μm], a porous carbon plate with electrolyte storage ribs having a pair of fuel passages and an air passage on the outside thereof, and a pair of porous carbon plates on the outside thereof. A cell was assembled by disposing a separator plate. The matrix was impregnated with 100% of the pore volume of phosphoric acid, and the electrode and the porous carbon plate were impregnated with about 40% of the pore volume of phosphoric acid. The air electrode was used to change the volume ratio C of the carbon in charge of the electrode catalyst layer in various ways. The cell is operated at a temperature of 200 ° C. by supplying fuel (H ₂ : CO ₂ = 80: 20) and air at a gas utilization of 80% and 60%, respectively.
After the characteristics were stabilized, the cell voltage E, the O ₂ gain ΔEo _{2 as} an index of the gas diffusivity of the air electrode, and the voltage drop IRc of the electrode catalyst layer at the air electrode were measured. In each case, the current density I was 300
[MA / cm ² ]. The results are shown in FIGS.

[0046] According to FIG. 4, as the volume ratio C of the carbon in charge of the electrode catalyst layer of the air electrode is increased, the voltage drop IRc electrode catalyst layer of the air electrode is reduced, the carbon responsible <br/> body When the volume ratio C is 10% to 15% or more, it tends to be saturated. Furthermore, as the volume ratio C of the carbon in charge of the electrode catalyst layer of the air electrode is increased, during cell operation O ₂ gain △ Eo ₂ gas diffusion index of the air electrode is increased, the cathode electrode catalyst layer volume ratio C of the carbon responsible body 20-2
At 5% or more, it tends to increase rapidly. From the above, to be a tentative standard of the volume ratio C is 10 to 25 [%] (preferably 15 to 20 [%]) is preferably in the range of carbon in charge of the electrode catalyst layer of the air electrode is from 4 I understand.

FIG. 5 shows a comprehensive examination of the above relationship. According to FIG. 5, O ₂ gain △ Eo voltage drop IRc and cell volume ratio C of the carbon responsible <br/> of the electrode catalyst layer of the air electrode is 10 to 20 [%] in the electrode catalyst layer of the air electrode The sum of ₂ is smaller. In particular the volume ratio C of the carbon responsible body 15
In the case of ２０20 [%], a small value of around 120 [mv] is preferable. Volume ratio C of the carbon in charge of these corresponding electrode catalyst layer of the air electrode is the cell voltage E in 10 to 25 [%] is high. In particular the volume ratio C of the carbon in charge are preferred has a high value of around 15 to 20 [%] in 650 [mv]. Further, the cell voltage E has become smaller ∂E / ∂C in this range is less likely affected by the volume ratio C of the carbon responsible body.

[0048] For example, in the case of mass production of the cell of the phosphoric acid fuel cell, the volume ratio C of the carbon in charge of the electrode catalyst layer of the air electrode 10 to 25 [%] (preferably 10 to 20
[%]), The sum of the voltage drop IRc of the electrode catalyst layer of the air electrode and the cell O ₂ gain △ Eo ₂ is small, the cell voltage E is correspondingly high, and the voltage is low. there is an effect that those less susceptible to volume ratio C of the carbon responsible body is obtained.

Embodiment 2 FIG. An electrode catalyst layer was produced in the same manner as in Example 1. Catalyst powder platinum is 20% by weight, carbon responsible body 72
% And an ash containing nickel as a main component of 8% were used. Carbon responsible body was using the heat treatment carbon. Catalyst powder / PTFE = 60/40 by weight ratio, basis weight 6.0 [m
g / cm ² ] and an air electrode electrode catalyst layer having a weight ratio of catalyst powder / PTFE = 60/40 and a basis weight of 15.0 [mg / cm ² ]. By changing the pressing pressure P when forming the electrode catalyst layer of the fuel electrode and the air electrode, to change the porosity epsilon, was measured volume ratio C and the electric resistivity ρ of the carbon in charge of this time . The result is shown in FIG.
And FIG.

[0050] In the second embodiment, since the composition of the electrode catalyst layer of the fuel electrode and the air electrode are the same, the fuel electrode and the same value is the volume ratio C and the electric resistivity ρ of the carbon in charge of the electrode catalyst layer of the air electrode became. In addition, according to FIG. 6, the porosity of the electrode catalyst layer ε is changed by the magnitude of the pressing pressure P. The porosity ε decreases as the pressing pressure P increases. Further, according to FIG. 7, as the porosity ε of the electrode catalyst layers of the fuel electrode and the air electrode increases, the volume ratio C of the carbon carrier of the electrode catalyst layer decreases, and the electric resistivity ρ of the electrode catalyst layer increases.
Is getting bigger. Conversely, the electric resistivity ρ of the electrode catalyst layer tends to decrease and become saturated when the porosity ε of the electrode catalyst layer is 75% to 80% or less. At this time, the volume ratio C of the carbon carrier in the electrode catalyst layer is 10 to 15 [%].
That is all.

[0051] Carbon paper was bonded to the electrode catalyst layers of the fuel electrode and the air electrode to form fuel electrode and air electrode, respectively. A cell was assembled using these fuel electrode and air electrode under the same conditions as in Example 1, and the cell was operated. 200
After operating at [° C.] and the characteristics were stabilized, gas diffusivity was evaluated at a current density I of 300 [mA / cm ² ]. H ₂ gain △ E _H2 which is an index of gas diffusivity of the fuel electrode
And O ₂ gain ΔEo ₂ , which is an index of gas diffusivity of the air electrode, was measured. The results are shown in FIGS. 8 and 9, respectively.

FIG. 8 shows that the porosity ε of the electrode catalyst layer of the air electrode is fixed at 65% and the porosity ε of the electrode catalyst layer of the fuel electrode is constant.
Is changed. As the porosity ε of the electrode catalyst layer of the fuel electrode increases, the H ₂ gain of the cell ΔE
_H2 is small, the porosity ε of the electrode catalyst layer of the fuel electrode
Tends to be saturated at 50 to 55 [%] or more. Also,
At this time, the volume ratio C of the carbon carrier in the electrode catalyst layer of the fuel electrode is about 20 to 25%.

Similarly, FIG. 9 shows a case where the porosity ε of the electrode catalyst layer of the air electrode is changed while the porosity ε of the electrode catalyst layer of the fuel electrode is kept constant at 65 [%]. As the porosity ε of the electrode catalyst layer of the air electrode increases, the O ₂ gain ΔEo _{2 of the} cell decreases, and the cell becomes saturated when the porosity ε of the electrode catalyst layer of the air electrode is 50 to 55% or more. There is a tendency. The volume ratio C of the carbon responsible <br/> of the electrode catalyst layer of the air electrode at this time is 20 to 25 [%] degree.

The following can be said from FIGS. 7 to 9.
That is, the porosity of the electrode catalyst layer of the fuel electrode and the air electrode ε is 75-80% or less (volume ratio C of the carbon responsible body 1
(About 0 to 15% or more), the electric resistance ρ of the electrode catalyst layer is desirably small. The porosity of the electrode catalyst layer of the fuel electrode ε is 50-55% or more H ₂ gain (volume ratio C is more than about 20 to 25 [%] of carbon responsible body) cell △
This is desirable because E _H2 is small. Furthermore, the porosity of the electrode catalyst layer of the air electrode ε is 50-55% or more (volume ratio C of the carbon responsible body 20-25% of around or less) of the cell O ₂
It is desirable that the gain △ Eo ₂ be small.

Therefore, the porosity ε of the electrode catalyst layers of the fuel electrode and the air electrode is set to 50 to 80% (preferably 60 to 7%).
0 [%] C.) and the volume ratio C of the carbon in charge of the electrode catalyst layer of the fuel electrode and the air electrode 10 to 25 [%] (preferably by 15 to 20 [%] or so), the electrode catalyst electrical resistivity of the layer ρ is small, what is obtained a voltage drop due to the electrical resistance is small, H ₂ gain further cell △ Eo ₂
Is obtained, the internal loss of the cell is reduced,
There is an effect that a high cell voltage can be obtained.

Embodiment 3 FIG. The electrode catalyst layer was created manufactured by the method as in Example 1. That is, the composition of the raw material catalyst powder was as follows in terms of weight ratio. Carbon black responsible body was using the heat treatment carbon.
Ash is a metal mainly composed of nickel. Sample A platinum 10 [%], carbon responsible 86 [%], ash 4
[%], Sample B Pt 20 [%], carbon responsible 72
[%], Ash 8 [%] Sample C Pt 30 [%], carbon responsible 58 [%], ash 12%, Sample D Platinum 40%, carbon responsible 44 [%], Ash content 16 [%]
including. Catalyst powder / PTFE = 60/40, was a basis weight 15.0 [mg / cm ^2] to create made an electrode catalyst layer of the air electrode of <br/> by weight. These electrode catalyst layer changes the porosity epsilon, was measured volume ratio C and the electric resistivity ρ of the carbon in charge of the electrode catalyst layer at this time. The results are shown in FIGS.

According to FIG. 10, the electric resistivity ρ of the electrode catalyst layer increases as the porosity ε of the electrocatalyst layer at the air electrode increases, and the degree of the increase is such that the platinum concentration of the raw material catalyst powder increases. Things are remarkable. On the other hand, according to FIG. 11, the electrical resistivity of the electrode catalyst layer as the volume ratio C of the carbon in charge of the electrode catalyst layer of the air electrode increases ρ is reduced, the influence of the concentration of platinum catalyst powder of raw material , And can be represented by a single curve. Display format according to FIG. 11, i.e., by considering the influence of the electrical resistivity ρ to volume ratio C of the carbon in charge of the electrode catalyst layer,
There is an effect that it is easy to estimate the electric resistance of the electrode catalyst layer and the voltage drop due to the electric resistance of the electrode.

[0058] Carbon paper was bonded to the electrode catalyst layers of these air electrodes to form air electrode electrodes. Example 1
A cell was assembled under the same conditions as in Example 1 using the fuel electrode prepared in the above and the air electrode, and the cell was operated. 200
After operating at [° C.] and the characteristics were stabilized, gas diffusivity was evaluated at a current density I of 300 [mA / cm ² ]. O ₂ gain △ Eo _2, which is an index of the gas diffusion property of the air electrode
Was measured. FIG. 12 shows the result. According to FIG. 12, as the porosity ε of the electrode catalyst layer of the air electrode increases, the O ₂ gain △ Eo _{2 of the} cell decreases, but is not significantly affected by the platinum concentration of the raw material catalyst powder. Roughly 1
It is distributed around the curve of the book.

[0059] Thus, referring to FIG. 11, the volume ratio C of the carbon in charge of the electrode catalyst layer 10% or more (preferably 1
5 [%] or more), the electrical resistivity ρ can be reduced, and FIG. 12 shows that the porosity ε of the electrode catalyst layer is 5%.
By selecting 0 [%] or more (preferably 60 [%] or more), the cell O ₂ gain △ Eo ₂ can be reduced, and the electrical resistivity ρ and the cell O ₂ gain can be reduced by combining both. A synergistic effect that can reduce both ΔEo ₂ is obtained.

Embodiment 4 FIG. An electrode catalyst layer was produced in the same manner as in Example 1. The catalyst powder contains 20 platinum by weight.
[%], A carbon carrier of 72 [%] and an ash containing nickel as a main component of 8 [%] were used. As the carbon carrier, heat-treated carbon was used. Catalyst powder / PTFE by weight ratio
= 100/0 to 40/60 and the amount of platinum was 1.8 [m
g / cm ² ] The porosity ε was 65 [%] to prepare an electrode catalyst layer of an air electrode. When catalyst powder / PTFE = 60/40,
The basis weight of the electrode catalyst layer is 15 [mg / cm ² ]. The volume ratio C, the thickness L, the electric resistivity ρ, and the electric resistance Rc of the carbon support in the electrode catalyst layer were measured. The result is shown in FIG.
And FIG.

According to FIG. 13, the P of the electrode catalyst layer of the air electrode is
As the TFE content [%] (weight ratio) increases,
The volume ratio C of the carbon support is small, and conversely, the thickness L of the electrode catalyst layer is large. Further, when the PTFE content is about 20 to 60%, the volume ratio C of the carbon carrier is about 10 to 25%. According to FIG. 14, as the volume ratio C of the carbon support in the electrode catalyst layer of the air electrode increases, the electrical resistivity ρ and the electrical resistance Rc of the electrode catalyst layer decrease, and the volume ratio C of the carbon support decreases by 15%. It tends to be saturated at about 20% or more. Carbon paper was bonded to the electrode catalyst layers of these cathodes to form cathode electrodes.

Further, a cell was assembled and operated under the same conditions as in Example 1 using the fuel electrode prepared in Example 1 and the above-mentioned air electrode. The cell voltage E, the O ₂ gain ΔEo _2, which is an index of gas diffusivity of the air electrode, and the air were supplied at a current density I of 300 [mA / cm ² ] after the characteristics were stabilized after operation at 200 ° C. The voltage drop IRc of the electrode catalyst layer of the pole was measured. The results are shown in FIGS. FIG.
According to the method, as the volume ratio C of the carbon support in the electrode catalyst layer of the air electrode increases, the voltage drop IRc of the electrode catalyst layer of the air electrode decreases, and the volume ratio C of the carbon support becomes about 10 to 15%. The above tends to saturate. Further, as the volume ratio C of the carbon support of the electrode catalyst layer of the air electrode increases, the O ₂ gain ΔEo ₂ of the gas diffusion index of the air electrode during cell operation increases, and the carbon support of the electrode catalyst layer of the air electrode increases. Tend to sharply increase when the volume ratio C of about 20% to 25% or more.

From the above, it can be seen from FIG. 15 that the volume ratio C of the carbon carrier in the electrode catalyst layer of the air electrode is desirably about 10 to 25%, preferably about 15 to 20%. FIG. 16 shows a comprehensive examination of the above relationship. According to FIG. 16, the sum of the voltage drop IRc of the electrode catalyst layer of the air electrode and the O ₂ gain ΔEo ₂ of the cell is small when the volume ratio C of the carbon carrier in the electrode catalyst layer of the air electrode is about 10 to 25 [%]. Has become. In particular, when the volume ratio C of the carbon carrier is about 15 to 20%, the value is as small as about 110 [mv], which is preferable. Corresponding to the above, the volume ratio C of the carbon support in the electrode catalyst layer of the air electrode is 10 to 25 [%].
The cell voltage is higher by the degree. In particular, when the volume ratio C of the carbon carrier is about 15 to 20%, a high value of about 650 [mv] is preferable.

Therefore, by controlling the volume ratio C of the carbon carrier in the electrode catalyst layer of the air electrode in the range of about 10 to 25 [%] (preferably about 15 to 20 [%]), Layer voltage drop IRc and cell O ₂
There is an effect that the sum of the gains ΔEo ₂ can be reduced, and the cell voltage E can be increased correspondingly. Specifically, according to FIG. 13, the PTFE content (weight ratio) of the electrode catalyst layer of the air electrode is about 20 to 60% (preferably 30%).
By controlling the volume ratio C of the carbon carrier to a range of about 10 to 25 [%] (preferably about 15 to 20 [%]), and the above-described effect is obtained. Can be

For example, when mass-producing cells of the phosphoric acid type fuel cell, the volume ratio C of the carbon carrier in the electrode catalyst layer of the air electrode is set to about 10 to 25% (preferably 15 to 2%).
0%) of the electrode catalyst layer.
If the E content is controlled, there is an effect that even if there is a slight change in the PTFE content at the time of preparing the electrode catalyst layer, the manufactured cell can have a high cell voltage and a small variation.

Embodiment 5 FIG. An electrode catalyst layer was produced in the same manner as in Example 1. The catalyst powder contains 20 platinum by weight.
[%], A carbon carrier of 72 [%] and an ash containing nickel as a main component of 8 [%] were used. As the carbon carrier, heat-treated carbon was used. Catalyst powder / PTFE by weight ratio
= 60/40, the porosity ε was 65 [%], and the volume ratio C of the carbon carrier was 19.3 [%]. It was prepared by changing the thickness L of the electrode catalyst layer to 50 to 400 [μm]. Carbon paper was bonded to the electrode catalyst layers of these cathodes to form cathode electrodes. Further, using the fuel electrode prepared in Example 1 and the above-mentioned air electrode, Example 1 was used.
The cell was assembled and operated under the same conditions as described above. 2
The cell voltage E, the O ₂ gain ΔEo _2, which is an index of gas diffusivity of the air electrode, and the air electrode were obtained at a current density I of 300 [mA / cm ² ] after the operation was stabilized at 00 [° C.]. Of the electrode catalyst layer was measured. The result is shown in FIG.
And FIG.

A method of increasing the amount of platinum by increasing the thickness of the electrode catalyst layer in order to increase the cell voltage has been conventionally known. 17 and 18 correspond to this. According to FIG. 17, the voltage drop IRc of the electrode catalyst layer of the air electrode increases in proportion to the thickness L of the electrode catalyst layer of the air electrode. On the other hand, the O ₂ gain ΔEo ₂ of the cell rapidly increases when the thickness L of the electrode catalyst layer is 300 to 350 [μm] or more. FIG. 18 comprehensively examines the above relationship.
According to FIG. 18, the thickness L of the electrode catalyst layer of the air electrode is 300
At ~ 350 [μm] or more, the sum of the voltage drop IRc of the electrode catalyst layer of the air electrode and the O ₂ gain ΔEo ₂ of the cell sharply increases. It is expected that the cell voltage is increased by increasing the thickness of the electrode catalyst layer of the air electrode.
It is high in the range of about 350 [μm]. In particular,
The thickness L of the electrode catalyst layer of the air electrode is 150 to 300 [μm]
In the range of the degree, a high value of about 650 [mv] is preferable.

Therefore, the thickness L of the electrode catalyst layer of the air electrode
Of about 100 to 350 [μm] (preferably 150 to 3
By controlling to within the range of about 00 [μm], a high cell voltage can be obtained, and the effect of the present invention can be further enhanced. Further, by optimizing the required amount of catalyst in the electrode catalyst layer of the air electrode, use of the catalyst becomes useless, which has the effect of contributing to a reduction in cell cost.

Embodiment 6 FIG. An electrode catalyst layer was produced in the same manner as in Example 1. The catalyst powder contains 20 platinum by weight.
[%], A carbon carrier of 72 [%] and an ash containing nickel as a main component of 8 [%] were used. As the carbon carrier, heat-treated carbon was used. Catalyst powder / PTFE by weight ratio
= 60/40, basis weight 15.0 [mg / cm ² ], porosity ε 6
5%, the volume ratio C of the carbon carrier is 19.3%
The electrode catalyst layer of the air electrode was prepared. Carbon paper was joined to the electrode catalyst layer of the air electrode to form an air electrode.
Similarly, in a weight ratio, catalyst powder / PTFE = 60 /
An electrode catalyst layer of a fuel electrode having a porosity of 40 [%] and a carbon carrier volume ratio C of 19.3 [%] was prepared.
It was manufactured by changing the thickness L of the electrode catalyst layer to 30 to 350 [μm]. Carbon paper was bonded to the electrode catalyst layers of these fuel electrodes to form fuel electrode electrodes.

Further, a cell was assembled using the above fuel electrode and air electrode under the same conditions as in Example 1, and the cell was operated. After operating at 200 ° C. and stabilizing the characteristics, when the current density I is 300 [mA / cm ² ], the H ₂ gain ΔE _H2 which is an index of the gas diffusion property of the fuel electrode and the electrode catalyst layer of the fuel electrode Was measured for the voltage drop IRc. The results are shown in FIGS. Conventionally, a method of increasing the amount of platinum by increasing the thickness of an electrode catalyst layer to increase the cell voltage has been known. 19 and 20 correspond to this. According to FIG. 19, the voltage drop IRc of the electrode catalyst layer of the fuel electrode increases in proportion to the thickness L of the electrode catalyst layer of the fuel electrode. On the other hand, the H ₂ gain ΔE _H2 of the cell increases rapidly when the thickness L of the electrode catalyst layer is 200 to 250 [μm] or more.

FIG. 20 shows a comprehensive examination of the above relationship.
It is. According to FIG. 20, the thickness L of the electrode catalyst layer of the fuel electrode
Is 200 to 250 [μm] or more, the sum of the voltage drop IRc of the electrode catalyst layer of the fuel electrode and the H ₂ gain ΔE _H2 of the cell sharply increases. It is expected that the cell voltage is increased by increasing the thickness of the electrode catalyst layer of the fuel electrode. It is high in the range of about 250 [μm]. In particular, when the thickness L of the electrode catalyst layer of the fuel electrode is 100 to 200 [μ
In the range of about [m], a high value of around 650 [mv] is preferable. Therefore, the thickness L of the electrode catalyst layer of the fuel electrode is set to about 50 to 250 μm (preferably 100 to 2 μm).
By controlling to within the range of about 00 [μm], a high cell voltage can be obtained, and the effect of the present invention can be further enhanced. Further, by optimizing the required amount of the catalyst in the electrode catalyst layer of the fuel electrode, the use of the catalyst becomes useless, which has the effect of contributing to a reduction in the cost of the cell.

Embodiment 7 FIG. Seven types of electrode catalyst layers were produced in the same manner as in Example 1. The following catalyst powder was used in a weight ratio of the composition. The platinum concentration is 5 to 50 [%]. As the carbon carrier, heat-treated carbon was used. Ash is a metal mainly composed of nickel. Sample E is platinum 5
[%], Carbon carrier 93 [%], ash 2 [%], sample F is platinum 10 [%], carbon carrier 86 [%], ash 4 [%], sample G is platinum 15 [%], carbon carrier 7
9 [%], ash content 6 [%], sample H was platinum 20 [%],
72% carbon support, 8% ash content, sample I was 30% platinum, 58% carbon support, 12 ash content
[%], Sample J was platinum 40 [%], carbon carrier 44
[%], Ash content 16 [%], Sample K contains platinum 50 [%], carbon carrier 30 [%], and ash content 20 [%].

Catalyst powder / PTFE = 60/4 by weight ratio
An electrode catalyst layer of an air electrode having a basis weight of 15.0 [mg / cm ² ] was prepared. The porosity ε of these electrode catalyst layers was changed, and the electric resistivity ρ and the electric resistance Rc of the electrode catalyst layers at this time were measured. The results are shown in FIGS. FIG.
According to the above, as the platinum concentration of the catalyst powder of the electrode catalyst layer of the air electrode increases, the electric resistivity ρ of the electrode catalyst layer increases, and the degree thereof increases as the porosity ε increases. When the platinum concentration of the catalyst powder is 40% or more, the electric resistivity ρ of the electrode catalyst layer tends to increase rapidly.

Further, according to FIG. 22, the electric resistance Rc of the electrode catalyst layer of the air electrode increases as the platinum concentration of the catalyst powder of the electrode catalyst layer of the air electrode increases. Larger ones are larger. When the platinum concentration of the catalyst powder is about 30 to 40% or more, the electric resistance Rc of the electrode catalyst layer tends to increase rapidly. Therefore, by using a catalyst powder having a platinum concentration of about 40% or less (preferably about 30% or less) in the catalyst powder of the electrode catalyst layer of the air electrode, the electric resistivity ρ and the electric resistance of the electrode catalyst layer are reduced. Since the resistance Rc can be reduced, the current distribution inside the cell can be made uniform, the Joule loss can be reduced, and the effect of the present invention can be further enhanced.

Further, by optimizing the platinum concentration of the catalyst powder in the electrode catalyst layer of the air electrode, the use of a catalyst having a higher platinum concentration than necessary at a high cost is unavoidable, and the effect of contributing to a reduction in cell cost can be obtained. is there. Of the electrode catalyst layers of these air electrodes, those having a porosity ε of 65 [%] were bonded with carbon paper to form electrodes of the air electrode. Further, a cell was assembled and operated under the same conditions as in Example 1 using the fuel electrode prepared in Example 1 and the air electrode. 200
After operating at [° C.] and the characteristics were stabilized, the current density I was 30
In the state of 0 [mA / cm ² ], the cell voltage E, the O ₂ gain ΔEo _2, which is an index of gas diffusivity at the air electrode, and the voltage drop IRc of the electrode catalyst layer at the air electrode were measured. The results are shown in FIGS.

According to FIG. 23, as the platinum concentration of the catalyst powder of the electrode catalyst layer of the air electrode increases, the voltage drop IRc of the electrode catalyst layer of the air electrode increases, and the platinum concentration of the catalyst powder becomes 30 to 40 [ %] Or more. Further, as the platinum concentration of the catalyst powder of the electrode catalyst layer of the air electrode increases, the O ₂ gain ΔEo ₂ of the gas diffusion index of the air electrode during cell operation increases, and the catalyst of the electrode catalyst layer of the air electrode increases. When the platinum concentration of the powder is about 30 to 40% or more, it tends to increase rapidly. As described above, from FIG. 23, the platinum concentration of the catalyst powder of the electrode catalyst layer of the air electrode is 40 [%].
It is understood that the content is desirably about 30% or less, preferably about 30% or less.

FIG. 24 shows a comprehensive examination of the above relationship.
It is. According to FIG. 24, when the platinum concentration of the catalyst powder of the electrode catalyst layer of the air electrode is about 30 to 40% or more, the sum of the voltage drop IRc of the electrode catalyst layer of the air electrode and the O ₂ gain ΔEo ₂ of the cell sharply increases. doing. Correspondingly, the cell voltage is high when the platinum concentration of the catalyst powder of the electrode catalyst layer of the air electrode is about 30 to 40% or less. When the platinum concentration of the catalyst powder is 10
Below about [%], the cell voltage is low because the amount of platinum in the electrode catalyst layer is small. It is expected that the cell voltage will be increased by increasing the platinum concentration of the catalyst powder in the electrode catalyst layer of the air electrode. Concentration 10
It is high in the range of about 40%. In particular, the platinum concentration of the catalyst powder of the electrode catalyst layer of the air electrode is 15 to 30.
In the range of about [%], a high value of about 650 [mv] is preferable.

Accordingly, the platinum concentration of the catalyst powder in the electrode catalyst layer of the air electrode is set to about 10 to 40% (preferably 1 to 40%).
With a range of about 5 to 30%, a high cell voltage can be obtained, and the effect of the present invention can be further enhanced. Further, by optimizing the platinum concentration of the catalyst powder in the electrode catalyst layer of the air electrode, it is unavoidable to use a catalyst having a higher platinum concentration than necessary at a high cost, which has the effect of contributing to a reduction in cell cost.

Embodiment 8 FIG. An electrode catalyst layer was produced in the same manner as in Example 1. The catalyst powder contains 20 platinum by weight.
[%], A carbon carrier of 72 [%] and an ash containing nickel as a main component of 8 [%] were used. As the carbon carrier, heat-treated carbon was used. Catalyst powder / PTFE by weight ratio
= 100/0 to 10/90 and the amount of platinum was 1.8 [m
g / cm ² ] of the air electrode. Catalyst powder /
When PTFE = 60/40, the basis weight of the electrode catalyst layer is 1
5 [mg / cm ² ], and when the porosity ε is 65 [%],
The volume ratio of the carbon carrier is 19.3 [%]. The porosity ε of these electrode catalyst layers was changed, and the electrical resistivity ρ of the electrode catalyst layer and the thickness L of the electrode catalyst layer at this time were measured. The results are shown in FIGS.

According to FIG. 25, P of the electrode catalyst layer of the air electrode
As the TFE content increases, the electric resistivity ρ of the electrode catalyst layer increases, and the degree thereof increases as the porosity ε increases. When the PTFE content of the electrode catalyst layer is 5
At about 0 to 60% or more, the electric resistivity ρ of the electrode catalyst layer tends to rapidly increase. According to FIG. 26, as the PTFE content of the electrode catalyst layer of the air electrode increases, the thickness L of the electrode catalyst layer increases, and the degree increases as the porosity ε increases. When the PTFE content of the electrode catalyst layer is about 50 to 60% or more, the thickness L of the electrode catalyst layer tends to increase rapidly.

Further, according to FIG. 27, as the PTFE content of the electrode catalyst layer of the air electrode increases, the electric resistance Rc of the electrode catalyst layer increases, and the degree thereof increases as the porosity ε increases. . When the PTFE content of the electrode catalyst layer is about 50 to 60% or more, the electric resistance Rc of the electrode catalyst layer tends to increase sharply. According to FIGS. 28 to 30, as the porosity ε of the electrode catalyst layer of the air electrode increases, the electric resistivity ρ of the electrode catalyst layer, the thickness L of the electrode catalyst layer, and the electric resistance Rc of the electrode catalyst layer increase. The larger the PTFE content of the electrode catalyst layer, the greater the degree. When the porosity ε of the electrode catalyst layer is about 70 to 75% or more, the electric resistivity ρ of the electrode catalyst layer, the thickness L of the electrode catalyst layer, and the electric resistance Rc of the electrode catalyst layer tend to increase rapidly.

Therefore, the PTF of the electrode catalyst layer of the air electrode is
By setting the E content to about 60% (preferably about 50%) or less and the porosity ε to about 70% or less, the electrical resistivity ρ of the electrode catalyst layer can be reduced.
The current distribution inside the cell can be made uniform, the Joule loss can be reduced, and the effect of the present invention can be further enhanced. Further, the PTFE content of the electrode catalyst layer of the air electrode was set to 60%.
Degree (preferably about 50%) or less, and a porosity ε of 7
By setting the value to about 0 [%] or less, the thickness L of the electrode catalyst layer can be reduced, which has an effect of contributing to downsizing of the cell and the fuel cell stack.

Further, by setting the PTFE content of the electrode catalyst layer of the air electrode to about 60% (preferably about 50%) and the porosity ε to about 70% or less,
There is an effect that the electric resistance Rc of the electrode catalyst layer and the voltage drop IRc thereof can be reduced. In addition, PT of the electrode catalyst layer of the air electrode
13 to 1 of Example 4 for the lower limit of the FE content.
The ratio is preferably about 20% (preferably about 30%) or more than 6. Although PTFE has been described as an example of the fluororesin, the same effect can be obtained even if the fluororesin is a tetrafluoroethylene-hexafluoropropylene copolymer, a tetrafluoroethylene-perfluoroalkylvinyl ether copolymer, or the like. Of course.

Embodiment 9 FIG. Eight types of electrode catalyst layers were produced in the same manner as in Example 1. The following catalyst powder was used as a raw material in terms of composition weight ratio. The platinum concentration was 20 [%], the ash was a metal mainly composed of nickel, and the carbon carrier used was heat-treated carbon. Sample L was platinum 20 [%], carbon carrier 80 [%], ash 0 [%], and sample M was platinum 2 [%].
0 [%], carbon carrier 76 [%], ash content 4 [%],
Sample N is platinum 20 [%], carbon carrier 72 [%], ash 8 [%], sample O is platinum 20 [%], carbon carrier 68 [%], ash 12 [%], and sample P is platinum 20 [%].
[%], Carbon carrier 64 [%], ash content 16 [%], sample Q is platinum 20 [%], carbon carrier 60 [%], ash content 20 [%], sample R is platinum 20 [%], carbon carrier 5
6%, ash content 24%, sample S was platinum 20%,
Contains 52% carbon carrier and 28% ash.

Catalyst powder / PTFE = 60/4 by weight
0, basis weight 15.0 [mg / cm ² ], platinum amount 1.8 [mg / cm ² ]
The electrode catalyst layer of the air electrode was prepared. The porosity ε of these electrode catalyst layers was changed, and the electric resistivity ρ and the electric resistance Rc of the electrode catalyst layers at this time were measured. The result is shown in FIG.
32 and FIG. According to FIG. 31, as the ash content of the electrode catalyst layer of the air electrode increases, the electric resistivity ρ of the electrode catalyst layer increases, and the degree thereof increases as the porosity ε increases. The ash content of the electrode catalyst layer is 10
Above about 15%, the electrical resistivity ρ of the electrode catalyst layer tends to increase rapidly. According to FIG. 32, as the ash content of the electrode catalyst layer of the air electrode increases, the electric resistance Rc of the electrode catalyst layer increases, and the degree thereof increases as the porosity ε increases. When the ash content of the electrode catalyst layer is about 10 to 15% or more, the electric resistance R of the electrode catalyst layer
c tends to increase sharply.

Therefore, the electric resistivity ρ of the electrode catalyst layer can be reduced by setting the ash content of the electrode catalyst layer of the air electrode to about 15% (preferably about 10%) or less, so that the inside of the cell can be reduced. The current distribution can be made uniform, the Joule loss can be reduced, and the effect of the present invention can be further enhanced. Further, the ash content of the electrode catalyst layer of the air electrode was set to 15
By setting it to not more than about [%] (preferably about 10%), the electric resistance Rc of the electrode catalyst layer and the voltage drop IRc of the electrode catalyst layer can be reduced. In addition,
In the present embodiment, the case of nickel as the ash has been described, but the ash is chromium, iron, cobalt, copper , ruthenium,
Needless to say, palladium and alloys thereof exhibit the same effect.

Comparative Example For comparison, an electrode catalyst layer was formed by a conventional technique using the configuration diagram of the conventional electrode catalyst layer shown in FIG. FIG.
The specifications were determined so as to be almost at the center of the hatched area shown in FIG. In FIG. 44, the platinum concentration of the catalyst powder (platinum loaded with platinum)
Amount , weight ratio) is 30%, the PTFE content (weight ratio) of the electrode catalyst layer is 50%, and the platinum amount of the electrode catalyst layer is 2.%.
7 [mg / cm ² ] and the thickness was 110 [μm]. Comparative Example A. In the catalyst powder, platinum was 30 [%], carbon carrier was 58 [%], and ash mainly composed of nickel was 12 [%] by weight ratio.
Was used. As the carbon carrier, heat-treated carbon was used. The volume ratio of the produced electrode catalyst layer was as follows.

[0088]

[Table 1]

The porosity ε is 33.6% and the electrical resistivity ρ
Was 1.04 [Ωcm]. Comparative Example B. As the catalyst powder, a platinum powder having a weight ratio of 30 [%], a carbon carrier of 70 [%] and containing no ash was used.
As the carbon carrier, heat-treated carbon was used. The volume ratio of the produced electrode catalyst layer was as follows.

[0090]

[Table 2]

The porosity ε is 29.3% and the electrical resistivity ρ
Was 0.68 [Ωcm]. As described above, in Comparative Examples A and B, regardless of the presence or absence of ash in the electrode catalyst layer, the porosity ε of the electrode catalyst layer manufactured by the conventional technique was very small, and was about 30%. Further, the electric resistivity ρ was higher than that of the electrode catalyst layer containing no ash.

Embodiment 10 FIG. For comparison with a comparative example, an electrode catalyst layer was prepared by the method of the present invention. Specifications are Examples 1 to 9
Based on the results, we decided as follows. When the platinum concentration of the catalyst powder is 2
0 [%], the PTFE content (weight ratio) of the electrode catalyst layer was 4
0 [%], the platinum amount of the electrode catalyst layer was 1.8 [mg / cm ² ], and the thickness was 185 [μm]. The catalyst powder used was 20 [%] of platinum, 72 [%] of a carbon carrier, and 8 [%] of ash containing nickel as a main component in weight ratio. As the carbon carrier, heat-treated carbon was used. The volume ratio of the produced electrode catalyst layer was as follows.

[0093]

[Table 3]

In this embodiment, the basis weight is 15.0 [mg / c
m ² ], the porosity ε is 64.7%, and the electrical resistivity ρ is 2.0.
7 [Ωcm]. In this example, the electrical resistivity ρ was slightly larger than that of the comparative example, but the porosity ε was about twice as large. Carbon paper was bonded to the electrode catalyst layer of the air electrode of this example and Comparative Example A to form an air electrode.
Further, a cell was assembled and operated under the same conditions as in Example 1 using the fuel electrode prepared in Example 1 and the two types of air electrodes. Before assembling the cells, phosphoric acid was applied to the electrode catalyst layers of the two air electrodes and the electrode catalyst layer of the fuel electrode. Phosphoric acid is about 40% of the pore volume of each electrode catalyst layer.
An amount occupying [%] was applied. Phosphoric acid has a concentration of about 10
0% and a temperature of about 120 ° C. were applied.

After the phosphoric acid application, the impregnation of the electrode catalyst layer of the fuel electrode was completed in about 1 [h]. The impregnation of the electrode catalyst layer manufactured according to the present example was completed at about 2 [h], but the impregnation time required for the electrode catalyst layer manufactured according to Comparative Example A was 20 [h] or more. This is because the electrode catalyst layer prepared according to Comparative Example A has a high PTFE content of 50%, a high water repellency , a small porosity of 33.6%, and a high density. This is because phosphoric acid was difficult to impregnate. On the other hand, the electrode catalyst layer produced according to this example has a PTFE content of 4%.
0 [%] and the water repellency is appropriate, porosity also 64.7
[%], Which is an appropriate value, because the impregnation with phosphoric acid was completed in a short time. Current density I is 300 at 200 [° C]
After operation for about 2500 [h] in the state of [mA / cm ² ], the cell voltage-current density characteristics were obtained. Further, when the current density I is 300
The cells were continuously operated in the state of [mA / cm ² ], and the cell voltage-operating time characteristics and O ₂ gain-operating time characteristics of the _two cells were evaluated. These results are shown in FIGS.

FIG. 33 shows the fuel (H ₂ : CO ₂ = 80: 2).
0) and the gas utilization rate of air were 80 [%] and 6 respectively.
The cell voltage-current density characteristics were adjusted while adjusting to 0 [%]. The electrode catalyst layer of the air electrode of the cell prepared by Comparative Example A had a low cell density, a high cell voltage, and a high current density. Is low. Further, the cell fabricated according to this example has a low cell voltage at a low current density and a high cell voltage at a high current density. This is platinum content of the electrode catalyst layer of the air electrode is that the electrode catalyst layer of the air electrode was prepared by Comparative Example A cell is large and 2.7 [mg / cm ^2], the cell voltage at a low current density < Although it is high , the porosity is as low as 33.6 [%], and the gas diffusivity is poor. Therefore, the cell voltage is low at a high current density. On the other hand, in the electrode catalyst layer prepared according to the present embodiment, the platinum amount of the electrode catalyst layer of the air electrode was as small as 1.8 [mg / cm ² ], so that the cell voltage was low at a low current density, but the porosity was low. 64.7
[%], And the gas diffusion property is good, so that the cell voltage is high at a high current density.

According to FIG. 34, when the electrode catalyst layer of the air electrode of the cell was prepared according to Comparative Example A, the cell voltage was higher in the early stage of operation than that prepared according to this example, but it was about 2%.
After 000 [h], the cell voltage is inverted and becomes lower, and the aging characteristics of the cell voltage thereafter are deteriorated. On the other hand, the electrode catalyst layer produced in this example shows a very low aging characteristic after about 2000 [h] although the cell voltage is slightly low in the initial stage of operation. According to FIG. 35 corresponding to these, in the case where the electrode catalyst layer of the air electrode of the cell was manufactured according to Comparative Example A, the O ₂ gain, which is an index of gas diffusivity of the air electrode, increased with time. . Meanwhile, those producing an electrode catalyst layer in this embodiment, O ₂ gain over time increase of less is indicative of a gas diffusion resistance of the air electrode. Therefore, when the electrode catalyst layer of the air electrode manufactured according to the present embodiment is used, the structure in the electrode catalyst layer is optimized, so that the cell voltage-current density characteristics are increased and the index of the gas diffusion property of the air electrode is increased. There is an effect that the increase with time of the O ₂ gain is small.

Embodiment 11 FIG. An electrode catalyst layer was produced in the same manner as in Example 1. The catalyst powder contains 20 platinum by weight.
[%], A carbon carrier of 72 [%] and an ash containing nickel as a main component of 8 [%] were used. As the carbon carrier, heat-treated carbon was used. Catalyst powder / PTFE by weight ratio
= 60/40, basis weight 15 [mg / cm ² ], porosity of about 90
[%] Was prepared. This electrode catalyst layer is divided into 5 parts,
Press molded. Press temperature from 20 [℃] to 300
What was changed to [° C] was prepared. A shim for a spacer is put around the electrode catalyst layer so that the porosity ε and the volume ratio C of the carbon carrier are the planned values in the finished dimensions of the electrode catalyst layer, and each of the electrode catalyst layers is 20, 50, 100, 20
Press molding was performed under five conditions of 0 and 300 ° C. The pressing pressure was adjusted in the range of 10 to 100 [kgf / cm ² ].

For example, a press temperature of 20 ° C. is 100 [kgf / cm ² ] and a press temperature of 50 [° C.] is 50 [kgf / cm ² ].
m ² ], 100 [° C.] are 30 [kgf / cm ² ], 200
Press molding was carried out by applying a surface pressure of about 20 [kgf / cm ² ] for [° C.] and about 10 [kgf / cm ² ] for 300 [° C.] for 5 minutes. After confirming that the porosity ε of the electrode catalyst layer after press molding and the volume ratio C of the carbon carrier were the same as planned values, the electric resistivity ρ was measured. The result is shown in FIG. According to FIG. 36, the electrode catalyst layer is
Press molding at a temperature of 00 [° C.] is smaller than when pressing at room temperature where the electric resistivity ρ of the electrode catalyst layer is about 20 [° C.], even though the volume ratio C of the carbon carrier is the same. Has become.

This is presumably because the PTFE behavior in the electrode catalyst layer is likely to flow during press molding by increasing the press molding temperature to room temperature or higher, causing a difference in PTFE behavior. As described above, by pressing the electrode catalyst layer at a temperature equal to or higher than room temperature, for example, at a temperature of 50 to 300 [° C.], the pressure for pressing the electrode catalyst layer is reduced to 1
0 to 50 [kgf / cm ² ], and the electrical resistivity ρ of the electrode catalyst layer can be reduced under the condition that the volume ratio C and the porosity ε of the carbon carrier are constant. Can be further enhanced.

Embodiment 12 FIG. An electrode catalyst layer was produced in the same manner as in Example 1. The catalyst powder contains 20 platinum by weight.
[%], A carbon carrier of 72 [%] and an ash containing nickel as a main component of 8 [%] were used. However, two types of carbon carriers, heat-treated carbon and non-heat-treated carbon (abbreviated as non-heat-treated carbon), were used. Catalyst powder / PTFE = 60/40 by weight ratio, basis weight 1
5 mg / cm ² and a porosity of about 65 [%] were prepared. Carbon paper was bonded to this type of electrode catalyst layer to form an air electrode. Furthermore, a cell was assembled and operated under the same conditions as in Example 1 using the fuel electrode prepared in Example 1 and the above two types of air electrodes. About 10,000 [h] at 200 [° C.] and a current density I of 300 [mA / cm ² ]
The cell was operated and the change over time in the cell voltage E was measured.

As shown in FIG. 37, when the heat-treated carbon was used as the carbon carrier for the electrode catalyst layer of the air electrode,
50 [mv], rising to 660 [mv] on the way, and last 655
[Mv], those using non-heat treated carbon have an initial 660
[Mv], and the final value was about 600 [mv]. For reference, as shown in FIG. 38, the O ₂ gain ΔE
to measure the time-dependent change of o _2. Before and after the operation test, the thickness L, the electric resistivity ρ, and the electric resistance Rc of the electrode catalyst layer of the air electrode of the cell were measured. These results are shown in FIG.
9-shown in FIG.

When the weight loss of the carbon carrier was analyzed before and after the operation test, the carbon carrier of the air electrode catalyst layer using heat-treated carbon hardly lost weight, but the carbon carrier using non-heat-treated carbon had a weight loss. 25%
As a result, the volume ratio C of the carbon carrier was reduced. This is because non-heat-treated carbon is more likely to be corroded and lost during cell operation than heat-treated carbon.
For this reason, as shown in FIG. 39, while the thickness L of the electrode catalyst layer was substantially constant before and after the operation test in the case where the heat treatment carbon was used as the carbon carrier of the electrode catalyst layer of the air electrode, the non-heat treatment carbon was used. The thickness L of the electrode catalyst layer was 2
It is thin near 0 [%]. This means that the occupation ratio of phosphoric acid in the pores of the electrode catalyst layer substantially increases and the gas diffusivity decreases, and as shown in FIG. 37 and FIG. This causes an increase in the O ₂ gain ΔEo ₂ , which is an index of the gas diffusion property of the pole.

According to FIG. 40, when the heat treatment carbon was used as the carbon carrier of the electrode catalyst layer of the air electrode, the electrical resistivity ρ of the electrode catalyst layer before and after the operation test was almost constant, Those using carbon had a large electric resistivity ρ before the operation test, and further increased after the operation test. The same can be said for the electric resistance Rc of the electrode catalyst layer in FIG. In order to effectively bring out the effects of the present invention, the internal structure and physical properties of the electrode catalyst layer represented by the volume ratio C, the porosity ε, the electric resistivity ρ, etc. of the carbon support of the electrode catalyst layer of the cell before operation are described. It is important that it does not change much over time during operation. Thus, in this embodiment, by using a heat treatment of carbon to carbon carrier of the electrode catalyst layer, by suppressing the loss due to corrosion of the carbon support in the cell operation, it can be reduced the time course of the internal structure and properties of the electrode catalyst layer Therefore, the change over time in the cell voltage E and the O ₂ gain ΔEo ₂ is improved, and the effect of the present invention can be further enhanced.

Embodiment 13 FIG. An electrode catalyst layer was produced in the same manner as in Example 1. The catalyst powder contained 20% platinum by weight and 72% carbon support by weight.
% And an ash containing nickel as a main component of 8% were used. Heat-treated carbon was used as the carbon black carrier. Catalyst powder / PTFE = 6 by weight on a charge basis
It was planned to have a ratio of 0/40 and a basis weight of 15 [mg / cm ² ]. Since an additive of an organic substance such as a dispersant was added to the electrode catalyst layer during the production , the influence of these additives was examined. First, two types were prepared, one in which the above additive was washed with acetone before heat treatment of the electrode catalyst layer and the other in which the additive was not washed. For washing acetone, the electrode catalyst layer was immersed in acetone for 20 hours.
Next, the ultrasonic vibration was applied to acetone.

After the final baking at about 360 ° C., the electrical resistivity ρ of the completed two types of electrode catalyst layers was measured. The result is shown in FIG. In the case where the acetone cleaning was not performed before the heat treatment during the preparation of the electrode catalyst layer, the weight and volume of the carbon carrier were reduced to about 70% of those cleaned with acetone. On the other hand, those washed with acetone had the basis weight as planned. According to FIG. 42, those without washing with acetone during the preparation of the electrode catalyst layer have an electrical resistivity ρ about 1 to 2 [Ωcm] larger than those with washing with acetone.

In the case where the electrode catalyst layer has not been washed with acetone during the production thereof, platinum contained in the electrode catalyst layer reacts with an organic additive during the final baking so that a part of the carbon carrier disappears. That is because On the other hand, in the case of washing with acetone, the volume ratio C of the electrode catalyst layer is reduced because the amount of the remaining organic additives is reduced and the loss of the carbon carrier is suppressed by heat treatment such as final baking. Largely maintained. In order to bring out the effects of the present invention, it is important to realize the internal structure of the electrode catalyst layer as planned. Therefore, in this embodiment, acetone cleaning is performed before the heat treatment during the preparation of the electrode catalyst layer to reduce the residual amount of the organic additive in the electrode catalyst layer, and the volume ratio C of the carbon carrier in the electrode catalyst layer is reduced. Since the proper state can be maintained, the effect of the present invention can be further enhanced. In the present embodiment it has been using acetone, also can be used other organic Solvent of course.

Embodiment 14 FIG. An electrode catalyst layer was produced in the same manner as in Example 1. As in Example 2, the catalyst powder used had a weight ratio of platinum of 20 [%], a carbon carrier of 72 [%], and an ash containing nickel as a main component of 8 [%]. As the carbon carrier, heat-treated carbon was used. Electrode catalyst layer of fuel electrode with weight ratio of catalyst powder / PTFE = 60/40, basis weight 6.0 [mg / cm ² ], and catalyst powder / PTFE = weight ratio
An electrode catalyst layer of a 60/40 air electrode having a basis weight of 15.0 [mg / cm ² ] was prepared. The fuel electrode and the air electrode were bonded to carbon paper with the porosity ε of the electrode catalyst layers being 65%, thereby forming the fuel electrode and the air electrode, respectively.

Further, the cell was assembled and operated under the same conditions as in Example 1. However, the phosphoric acid application amount of the electrode catalyst layer of the air electrode changed the phosphoric acid occupancy of the electrode catalyst layer of the air electrode to 10 to 90 [%]. Temperature 200
After operating at [° C.] and a current density I of 300 [mA / cm ² ] and the characteristics were stabilized, the fuel (H ₂ : CO ₂ = 80: 20) and air were used at a gas utilization rate of 80% each. , And 60
[%] While adjusting the current density I to 100 to 800 [mA
/ Cm ² ] and the cell voltage E at that time was measured. This is shown in FIG. If the phosphoric acid occupation ratio is too small, phosphoric acid becomes insufficient, and if it is too large, gas diffusion deteriorates, and this is reflected in the cell voltage. According to FIG.
The phosphoric acid occupancy of the electrode catalyst layer of the air electrode is 30 to 70%.
In the range, the cell voltage is high. In particular, the phosphate occupancy is 40
In the range of 〜60 [%], the cell voltage shows the maximum value, which is preferable. FIG. 44 shows the porosity instead of the phosphoric acid occupancy.

According to FIG. 44, the cell voltage is high when the porosity of the electrode catalyst layer of the air electrode after phosphoric acid impregnation is in the range of 20 to 45 [%]. In particular, when the porosity is in the range of 25% to 40%, the cell voltage shows the maximum value, which is preferable. To reduce the cost of the fuel cell, it is necessary to increase the current density. Thus, even at a high current density of 400 [mA / cm ² ] or more, the porosity of the electrode catalyst
[%] (Preferably 25 to 40 [%]), and the ability to stably take a load can further enhance the effect of the present invention.

In this embodiment, the air electrode has been described. However, it is needless to say that the present invention can be applied to a fuel electrode. Although the embodiment of the present invention has been described mainly with respect to the air electrode, it is needless to say that the present invention can be similarly applied to the fuel electrode. Furthermore, although platinum has been described as a catalyst metal, it is needless to say that the present invention can be similarly applied to a case where a catalyst metal such as palladium, rhodium, iridium, ruthenium, and osmium other than platinum is contained.

[0112]

As described above, the first aspect of the present invention relates to a matrix impregnated with an electrolyte, a pair of fuel and air electrodes provided on both sides of the matrix, and an electrode comprising these electrodes. In a fuel cell electrode formed by stacking a plurality of unit cells each including a pair of fuel flow paths and an air flow path formed outside the fuel cell via a separator, at least one of the fuel electrode and the air electrode The electrode catalyst layer comprises a catalyst powder in which platinum and ash, which is one or more metal elements other than platinum, are supported on a carbon black carrier, and a fluororesin, and the volume ratio of the carbon black carrier is 10-25
[%] (Preferably 15 to 20 [%]), the cell voltage-current density characteristics and the aging characteristics of the cell voltage can be further improved, and the electrode catalyst layer is impregnated with an electrolyte such as phosphoric acid. This has the effect of speeding up.
Further, there is an effect that the voltage drop due to the electrical resistance can be reduced by reducing the sum of the O ₂ gains and the cell voltage can be increased.

According to a second aspect of the present invention, the porosity of the electrode catalyst layer is set to 50 to 80% (preferably 60 to 70%).
[%]), The voltage drop due to electric resistance, the H ₂ gain, and the O ₂ gain are reduced, and the cell voltage can be increased.

A third aspect of the present invention is that the content of the fluororesin in the electrode catalyst layer is 20 to 60% (preferably 30%).
50 since the [%]), an effect that a small can cell voltage the sum of the voltage drop and O ₂ gain due to electrical resistance can be increased.

According to a fourth aspect of the present invention, the platinum concentration (content ) of the catalyst powder in the electrode catalyst layer is set to 10 to 40% (preferably 15 to 30%). This has the effect that the sum of the voltage drop and the O ₂ gain can be reduced and the cell voltage can be increased.

A fifth aspect of the present invention is that the ash content of the catalyst powder in the electrode catalyst layer is 15% (preferably 10%).
[%]), The effect of reducing the electric resistivity and electric resistance can be achieved.

According to a sixth aspect of the present invention, the porosity of the electrode catalyst layer is set to 20 to 45% (preferably 25 to 40%).
[%]), The cell voltage can be increased.

A seventh aspect of the present invention is that the carbon black carrier of the catalyst powder of the electrode catalyst layer has a density of 1.8 [g / c.
m ³ ] or more as a heat-treated carbon support, the effect of improving the aging characteristics of cell voltage and O ₂ gain is obtained.

The eighth aspect of the present invention is that the thickness of the air electrode catalyst layer is 100 to 350 [μm] (preferably 150 to 350 μm).
300 [μm]), the sum of the voltage drop due to electric resistance and the O ₂ gain can be reduced, and the cell voltage can be increased.

According to a ninth aspect of the present invention, the fuel electrode catalyst layer has a thickness of 50 to 250 μm (preferably 100 to 2 μm).
00 since the [μm]), an effect that the sum of the voltage drop and H ₂ gain due to electrical resistance can be increased less able cell voltage.

A tenth aspect of the present invention is that the electrode catalyst layer is formed at a temperature in the range of 50 to 300 ° C. and a temperature of 10 to 50 kgf.
/ Cm ² ], which has the effect of reducing the electrical resistivity of the electrode catalyst layer.

The eleventh aspect of the present invention includes a step of extracting and removing organic substances while applying ultrasonic vibration by immersion in an organic solvent such as acetone before press molding. Therefore, there is an effect that a low-cost and highly reliable fuel cell can be provided.

[Brief description of the drawings]

FIG. 1 is a diagram showing a relationship between a pressing pressure and a volume ratio of a carbon carrier of an electrode catalyst layer of an air electrode in Example 1 of the present invention.

FIG. 2 is a diagram showing a relationship between a volume ratio of a carbon carrier, a porosity, and a thickness of an electrode catalyst layer of an air electrode in Example 1 of the present invention.

FIG. 3 is a diagram showing a relationship between a volume ratio of a carbon carrier in an electrode catalyst layer of an air electrode, an electric resistivity, and an electric resistance in Example 1 of the present invention.

FIG. 4 shows the volume ratio and the voltage drop of the carbon carrier in the electrode catalyst layer of the air electrode and the O drop of the cell in Embodiment 1 of the present invention.
FIG. 3 is a diagram illustrating a relationship with _two gains.

FIG. 5 is a diagram showing a relationship between a volume ratio of a carbon carrier in an electrode catalyst layer of an air electrode and a voltage drop + O ₂ gain of a cell and a cell voltage in Example 1 of the present invention.

FIG. 6 is a diagram showing a relationship between a pressing pressure and a porosity of an electrode catalyst layer of a fuel electrode and an air electrode in Embodiment 2 of the present invention.

FIG. 7 is a diagram showing a relationship between a volume ratio of a carbon support in an electrode catalyst layer of a fuel electrode and an air electrode, and an electrical resistivity and a porosity in Example 2 of the present invention.

FIG. 8 is a diagram showing the relationship between the porosity of the electrode catalyst layer of the fuel electrode, the H ₂ gain of the cell, and the volume ratio of the carbon carrier in Example 2 of the present invention.

FIG. 9 is a diagram showing the relationship between the porosity of the electrode catalyst layer of the air electrode, the O ₂ gain of the cell, and the volume ratio of the carbon carrier in Example 2 of the present invention.

FIG. 10 is a diagram showing the relationship between the porosity of the electrode catalyst layer of the air electrode and the electrical resistivity in Embodiment 3 of the present invention.

FIG. 11 is a diagram showing a relationship between a volume ratio of a carbon carrier of an electrode catalyst layer of an air electrode and an electric resistivity in Embodiment 3 of the present invention.

FIG. 12 is a diagram showing the relationship between the porosity of the electrode catalyst layer of the air electrode and the O ₂ gain of the cell in Embodiment 3 of the present invention.

FIG. 13 is a diagram showing the relationship between the PTFE content and the thickness of the electrode catalyst layer of the air electrode in Example 4 of the present invention.

FIG. 14 is a diagram showing a relationship between a volume ratio of a carbon carrier in an electrode catalyst layer of an air electrode, an electric resistivity and an electric resistance in Embodiment 4 of the present invention.

FIG. 15 is a diagram showing a relationship between a volume ratio of a carbon carrier in an electrode catalyst layer of an air electrode, a voltage drop, and an O ₂ gain of a cell in Embodiment 4 of the present invention.

FIG. 16 is a graph showing the relationship between the volume ratio of the carbon carrier in the electrode catalyst layer of the air electrode and the voltage drop + O _{2 of the} cell in Example 4 of the present invention
FIG. 3 is a diagram illustrating a relationship between a gain and a cell voltage.

FIG. 17 is a diagram showing the relationship between the thickness of the electrode catalyst layer of the air electrode, the voltage drop, and the O ₂ gain of the cell in Embodiment 5 of the present invention.

FIG. 18 is a diagram showing the relationship between the thickness of the electrode catalyst layer of the air electrode and the voltage drop + O ₂ gain of the cell and the cell voltage in Example 5 of the present invention.

FIG. 19 is a diagram showing the relationship between the thickness of the electrode catalyst layer of the fuel electrode, the voltage drop and the H ₂ gain of the cell in Embodiment 6 of the present invention.

FIG. 20 is a diagram showing the relationship between the thickness of the electrode catalyst layer of the fuel electrode and the voltage drop + H ₂ gain of the cell and the cell voltage in Embodiment 6 of the present invention.

FIG. 21 is a diagram showing the relationship between the platinum concentration of the catalyst powder of the electrode catalyst layer of the air electrode and the electrical resistivity in Example 7 of the present invention.

FIG. 22 is a diagram showing the relationship between the platinum concentration of the catalyst powder of the electrode catalyst layer of the air electrode and the electric resistance in Example 7 of the present invention.

FIG. 23 shows the platinum concentration and the voltage drop of the catalyst powder of the electrode catalyst layer of the air electrode and the O _{2 of the} cell in Example 7 of the present invention.
FIG. 4 is a diagram illustrating a relationship with a gain.

FIG. 24 is a diagram showing the relationship between the platinum concentration of the catalyst powder of the electrode catalyst layer of the air electrode and the voltage drop + O ₂ gain of the cell and cell voltage in Example 7 of the present invention.

FIG. 25 is a diagram showing the relationship between the PTFE content of the electrode catalyst layer of the air electrode and the electrical resistivity in Example 8 of the present invention.

FIG. 26 is a diagram showing the relationship between the PTFE content and the thickness of the electrode catalyst layer of the air electrode in Example 8 of the present invention.

FIG. 27 is a diagram showing the relationship between the PTFE content of the electrode catalyst layer of the air electrode and the electric resistance in Example 8 of the present invention.

FIG. 28 is a diagram showing the relationship between the porosity of the electrode catalyst layer of the air electrode and the electrical resistivity in Example 8 of the present invention.

FIG. 29 is a diagram showing the relationship between the porosity and the thickness of the electrode catalyst layer of the air electrode in Example 8 of the present invention.

FIG. 30 is a diagram showing the relationship between the porosity of the electrode catalyst layer of the air electrode and the electric resistance in Example 8 of the present invention.

FIG. 31 is a diagram showing the relationship between the ash content of the electrode catalyst layer of the air electrode and the electrical resistivity in Example 9 of the present invention.

FIG. 32 is a diagram showing the relationship between the ash content of the electrode catalyst layer of the air electrode and the electric resistance in the ninth embodiment of the present invention.

FIG. 33 is a diagram showing cell voltage-current density characteristics in Example 10 of the present invention.

FIG. 34 is a diagram showing cell voltage-operating time characteristics in Embodiment 10 of the present invention.

FIG. 35 is a diagram showing O ₂ gain-operating time characteristics of a cell according to Embodiment 10 of the present invention.

FIG. 36 is a diagram showing the relationship between the press forming temperature and the electrical resistivity of the electrode catalyst layer of the air electrode in Example 11 of the present invention.

FIG. 37 is a diagram showing cell voltage-operating time characteristics in Embodiment 12 of the present invention.

FIG. 38 is a diagram showing O ₂ gain-operating time characteristics of a cell according to Embodiment 12 of the present invention.

FIG. 39 is a diagram showing a thickness of an electrode catalyst layer of an air electrode in Embodiment 12 of the present invention.

FIG. 40 is a diagram showing the electric resistivity of the electrode catalyst layer of the air electrode in Example 12 of the present invention.

FIG. 41 is a diagram showing electric resistance of an electrode catalyst layer of an air electrode in Embodiment 12 of the present invention.

FIG. 42 is a diagram showing the relationship between the porosity of the electrode catalyst layer of the air electrode and the electrical resistivity in Example 13 of the present invention.

FIG. 43 is a diagram showing a relationship between a phosphoric acid occupancy of an electrode catalyst layer of an air electrode and a cell voltage in Example 14 of the present invention.

FIG. 44 is a diagram showing the relationship between the porosity of the electrode catalyst layer of the air electrode and the cell voltage in Example 14 of the present invention.

FIG. 45 is a diagram showing an optimal region of a platinum amount and a thickness of a conventional electrode catalyst layer.

Claims (11)

(57) [Claims] 1. A matrix impregnated with an electrolyte, an electrode comprising a pair of fuel electrodes and an air electrode provided on both sides of the matrix, and a pair of fuel channels and an air channel formed outside these electrodes. In the electrode of the fuel cell formed by laminating a plurality of unit cells comprising a separator with a separator, at least one electrode catalyst layer of the fuel electrode and the air electrode, except for platinum and platinum in the carbon black carrier It is composed of a catalyst powder carrying at least one ash as a metal element and a fluororesin, and a volume ratio of the carbon black carrier is 10% to 25% with respect to the electrode catalyst layer. Electrodes for fuel cells. 2. The porosity of the electrode catalyst layer is 50% to 80%.
The fuel cell electrode according to claim 1, wherein: 3. The fluororesin content of the electrode catalyst layer is 20%.
2. The electrode for a fuel cell according to claim 1, wherein the amount is from about 60% to about 60%. 3. 4. The platinum content in the catalyst powder is from 10% to 4%.
2. The fuel cell electrode according to claim 1, wherein said electrode is 0%. 5. The fuel cell electrode according to claim 1, wherein the ash content in the catalyst powder is 15% or less. 6. The porosity of the electrode catalyst layer is from 20% to 45%.
The fuel cell electrode according to claim 1, wherein: 7. The carbon black carrier has a density of 1.8.
2. The fuel cell electrode according to claim 1, wherein the electrode is a heat-treated carbon of g / cm ³ or more. 8. The thickness of the electrode catalyst layer of the air electrode is 100 μm.
2. The electrode for a fuel cell according to claim 1, wherein the diameter is from m to 350 [mu] m. 9. The thickness of the electrode catalyst layer of the fuel electrode is 50 μm.
2. The electrode for a fuel cell according to claim 1, wherein the thickness is from 250 to 250 [mu] m. 10. An electrode catalyst layer comprising a catalyst powder in which a carbon black carrier carries platinum and ash, which is one or more metal elements other than platinum, and a fluororesin, are heated at 50 ° C.
Temperature in the range of 300 ° C. and 10 kgf / cm ^{2 to} 50 kgf / c
A method for producing an electrode for a fuel cell, comprising a step of press molding at a pressure in the range of m ² . 11. immersing the electrode catalyst layer before press-forming organic Solvent <br/>, then the step of extracting and removing the organic material of the electrode catalyst layer while applying ultrasonic vibration to the electrode catalyst layer The method for producing an electrode for a fuel cell according to claim 10, comprising: