Method and apparatus for forming electrode catalyst layer by electrospray method

A method for forming an electrode catalyst layer by an electrospray method, including putting catalyst ink within a container having a nozzle in communication with the interior of the container and applying an electrospray voltage to the catalyst ink to cause electrospray of the catalyst ink through the tip end of the nozzle and thereby to form an electrode catalyst layer, the method comprising:

• preparing catalyst ink containing a mixture of at least electrode catalyst, polymer electrolyte binder and volatile organic compound and/or water;
• putting the catalyst ink within the container with a space remaining inside thereof, and air-tightly sealing the container;
• and
• electrospraying with the space inside of the air-tightly sealed container being conditioned to have a negative pressure of a level at which the catalyst ink cannot drip off from the nozzle.

An apparatus for forming an electrode catalyst layer by an electrospray method comprising:

• a retaining mechanism for retaining an air-tightly sealable container within which catalyst ink is put with a space filled with gas remaining inside thereof and a nozzle in communication with a lower portion of an interior of the container;
• a medium holding member arranged on an extension of the nozzle retained by the retaining mechanism and holding on the surface thereof a film-like medium to be formed with an electrode catalyst layer;
• a pressure measuring device for measuring the pressure within the space inside of the container retained by the retaining mechanism;
• a pressure adjusting device for conditioning the space inside of the container retained by the retaining mechanism to have a negative pressure;
• and
• a voltage-adjustable high-voltage generator for applying an electrospray voltage between the catalyst ink within the container or the nozzle and the film-like medium or the medium holding member.