Toppan Printing Reveals Sequential Stacking Method for Nanomaterials Used in Fuel Cell Membrane Electrode Assemblies

In U.S. Patent Application 20100062306, Toppan Printing Co., Ltd. (Tokyo, JP) chemists reveal a highly efficient, low cost manufacturing method for membrane electrode assemblies (MEAs) using nanoparticle catalytic inks to produce robust proton exchange membrane fuel cells (PEMFCs).  

The MEA manufacturing methods includes coating a first catalyst ink on a substrate to form a coated layer, removing the solvent in the coated layer to form a first electrode catalyst layer, coating an electrolyte ink on the first electrode catalyst layer to form a coated layer of the electrolyte ink, removing the solvent in the coated layer of the electrolyte ink to form a polymer electrolyte membrane, coating a second catalyst ink on the polymer electrolyte membrane to form a coated layer of the second catalyst ink, and removing the solvent in the coated layer of the second catalyst ink to form a second electrode catalyst layer.

The catalyst material is loaded on a conductive carrier. Any known conductive carrier can be used as the conductive polymer. A carbon particle is a representative material of the conductive polymer. Specifically, carbon black, acetylene black, ketjen black, carbon nanotube and fullerene  are examples of the carbon particle and can be used in the Toppan Printing's fabrication method. 

The size (diameter) of the conductive particle is preferred to be in the range of 10-1000 nanometers (nm) because it becomes difficult to form a path for electron conduction if the conductive particle is too small, whereas the gas diffusion properties of the electrode catalyst layer decrease and catalytic efficiency falls if the conductive particle is too large. It is more preferable that the size (diameter) of the conductive particle is in the range of 10-100 nm. 

FIG. 5 is a scanning electron microscope (SEM) picture of a cross section of an MEA manufactured by Toppan Printing's sequential stacking method

Toppan Printing's fabrication technique makes it possible to produce MEAs with high level gas diffusion properties and drainage properties. 

Toppan Printing manufacturing method can be applied to a polymer electrolyte fuel cells used in electric cars, portable electronics, vending machines, underwater robots, submarines, space ships, or even a power supply for an underwater base