JPS6248348B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical field to which the invention pertains] The present invention relates to a method for manufacturing a fuel cell electrode formed by laminating a carbon catalyst layer and a sintered nickel layer. [Prior art and its problems] In order to prevent fuel or oxidizer gas that comes into contact with the carbon catalyst layer made of activated carbon, carbon black, or graphite from blowing through to the electrolyte side, such an electrode is used as a liquid-side layer for electrolysis. It has a porous sintered nickel layer that is easily wetted by liquid, and the three-phase interface where the reaction proceeds (the surface where gas, electrolyte, and catalyst come into contact with each other) is fixed within the catalyst layer. .
Bonding between the carbon catalyst layer and the sintered nickel layer is carried out by mixing polytetrafluoroethylene resin in the catalyst layer and hot pressing it together with the nickel layer.In this case, increasing the binder content Much of the catalyst surface is covered with binder, reducing catalyst performance.
On the other hand, if the binder content is reduced, interlayer peeling will occur after long-term discharge, resulting in a decrease in electrode performance. [Object of the Invention] In contrast, an object of the present invention is to provide a method for manufacturing a fuel cell electrode that firmly binds a carbon catalyst layer and a sintered nickel layer without using a large amount of binder. [Summary of the Invention] According to the present invention, this object is achieved by stacking a mesh on a layer of a mixture of nickel powder and resin having an uneven surface, applying pressure, removing the mesh, sintering the nickel powder, and forming a mesh on the surface. This is achieved by creating a sintered nickel layer having an uneven surface, overlaying a carbon catalyst layer containing a binder on the uneven surface of the nickel layer, and pressurizing the layer at high temperature. [Embodiments of the Invention] The present invention will be described below with reference to Examples and figures. <Example> Nickel powder and polyacrylate resin are kneaded and formed into a 0.2 mm thick sheet, and then, for example,
Layer 250 mesh nickel nets together and apply a pressure of 100 kg/cm ² to make the nets bite into the sheet surface. Next, when this net is removed, since the nickel still has elasticity, the folds 7 of the nickel sheet 6 that covered the top of the net before the net was removed will disappear as the net is pulled up, as shown in Figure 2. Although it warps upward for a time, it returns to its original state and grooves 8 from which the folds 7 of the nickel sheet protrude are formed in the recesses formed when the mesh disappears. Therefore, when this is sintered at 900° C. for 1 hour in a hydrogen stream, irregularities corresponding to the mesh are formed on the surface to which the mesh is crimped. This recess is
The inlet is dovetail-shaped, narrower than the inner diameter. The carbon catalyst layer 2 was layered on the uneven surface of the sintered nickel layer 4 thus obtained in the same way as in Example 1, and the first
The electrode 5 shown in the figure is obtained. In this electrode, the powder of the carbon catalyst layer is embedded in the dovetail groove-like irregularities of the sintered nickel layer, and a strong bond is obtained at the boundary due to the so-called wedge effect. Table 1 compares the bonding strength between the electrode body obtained in this example and an electrode in which a carbon catalyst layer containing the same amount of binder as in the example was bonded to a sintered nickel layer with a smooth surface. and show. It can be seen from this that the embodiment of the present invention is superior.

〔Effect of the invention〕

As described above, in the present invention, a sintered nickel layer having an uneven surface is created in advance, and the carbon catalyst layer is bonded to the uneven surface, so that the powder of the catalyst layer gets stuck in the recesses, resulting in a wedge effect. As a result, a strong bond between the nickel layer and the catalyst layer is obtained, and since there is no need to increase the amount of binder, the catalyst performance is not impaired, making it an excellent fuel with stable characteristics even during long discharges. A battery electrode can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of an electrode according to an embodiment of the present invention;
FIG. 2 is an enlarged view of the main part of the nickel sheet before sintering according to the present invention. 2... Carbon catalyst layer, 4... Sintered nickel layer, 5... Electrode.

Claims (1)

[Claims] 1 After placing a mesh on a layer of a mixture of nickel powder and resin and applying pressure, the mesh is removed and the nickel powder is sintered to create a sintered nickel layer with a mesh pattern on the surface, and the uneven surface of the nickel layer is 1. A method for producing a fuel cell electrode, which comprises stacking a carbon catalyst layer containing a binder on top and pressurizing it at high temperature.