Method for making membrane fuel cell electrodes by low-voltage electrophoretic deposition of carbon nanomaterial-supported catalysts

A method for making a membrane fuel cell (MFC) electrode by low-voltage electrophoretic deposition (EPD) of carbon nanomaterial (CNM) supported catalyst comprising the steps of:

• providing an aqueous cathode EPD suspension via mixing an ionomer solution with electrolyte;
• providing an aqueous anode EPD suspension which is different from said aqueous cathode EPD suspension, via mixing a CNM-supported nanocatalyst with a solution of the same composition as that of the cathode EPD suspension, wherein a dry ratio of the CNM-supported nanocatalyst to the ionomer is 1:10 to 1:4 and wherein the CNM-supported nanocatalyst comprises 10 to 90 wt %;
• executing ultrasonication before and then, separately, high-speed stirring on both the cathode EPD suspension and the anode EPD suspension, respectively, thus turning them into catalyst/ionomer composites and homogenous suspensions;
• providing a low-voltage EPD apparatus with a porous membrane arranged to divide the low-voltage EPD apparatus into an anode compartment and a separate cathode compartment;
• filling the anode and cathode EPD suspensions in the anode compartment and cathode compartment, respectively such that the porous membrane inhibits mixing of generated gases with one another;
• introducing an inert gas into the anode compartment for stirring the anode EPD suspension and inhibiting formation of precipitation of the anode EPD suspension;
• providing an electrode base substrate selected from the group consisting of non-catalyzed gas diffusion electrode, carbon paper and carbon cloth as the anode and a platinum mesh as the cathode in the EPD apparatus;
• providing a low-voltage DC power supply to provide less than 5 volts DC to the EPD apparatus to evenly coat the composite of the CNM-supported nanocatalyst and the ionomer so as to form a catalyst layer on the electrode base substrate;
• removing the substrate coated with the catalyst layer from the EPD apparatus;
• washing the catalyst layer coated on the electrode base substrate with de-ionized water;
• and
• drying the catalyst layer coated on the substrate, thus forming the MFC electrode.