Ultrasonic Spray For MEA Fabrication

Ultrasonic spray coating technique is replacing air spray coating technique in a wide range of industrial and R&D applications, such as photo resistor coating, solar cell industry and fuel cell industry. Ultrasonic spray coating is a technology that is more precise, more controllable, and tighter of drop distribution. Tight drop distribution and non-clogging ultrasonic create very uniform thin films, therefore, ultrasonic spray coating technique is very suitable for fabricate ultra-low Pt loading MEAs. But, the cost of ultrasonic spray system is higher than air spray coating system or screen printing coating system. The high cost of system is the main disadvantage of ultrasonic spray coating in the fuel cell industry.

These coating methods have been included, as they have shown the most promising results for ultra-low Pt loaded MEAs. Electrospray and plasma sputter demonstrate extremely high cathode mass power density when Pt loading was one order of magnitude lower than other methods. When the Pt loading increases, the cathode mass power density decreases regardless of the coating technique used. It would be expected that ultrasonic coating would achieve comparably high cathode mass power density if the Pt loading was decreased one order of magnitude.

However, the performance would decrease more than 20% when the Pt loading was one order of magnitude lower. While this would reduce the cost of catalyst, it would also have negative impacts on the cost of other components of the fuel cell stack, and the volume (weight) of the fuel cell stack would need to be increased to achieve the same power output.

Ultrasonic spray technique can be delivered high cathode mass power density and fuel cell performance using the described laboratory MEA fabrication technique.