Fuel cells

Fuel cells based on ionomer membranes are very important e.g. for zero emission vehicles. State-of-the-art are polymer electrolyte membrane H₂/O₂ fuel cells. However, the next generation of fuel cells are working with methanol as fuel. A disadvantage of the used commercially available membranes such as Nafion in direct methanol fuel cells (DMFC) is their relatively large permeability of methanol, which leads to a drastic degradation of the efficiency of the fuel cell. By plasma treating of such membranes the permeability can be reduced and additionally the adhesion of the catalyst to the membrane can be improved. Both leading to an increased performance of the fuel cell.

A further important component of a fuel cell is the porous gas diffusion layer (GDL). A GDL provides a homogeneous gas flow to the catalyst and should control the water content of the cell. Especially the water management in a wide range of the voltage/current polarization curves of the fuel cell is very important for a high fuel cell efficiency. However, the GDLs mostly consist of a strong hydrophobic material which is critical for a proper water management. A partial hydrophilic GDL is the better choice, because a certain amount of water can be retained in the cell. This can be achieved with a “surface structured” plasma treatment of the GDL. Now, a certain amount of water can be retained in the cell leading to a better fuel cell performance.