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Fuel cells

Fuel cells based on ionomer membranes are very important e.g. for zero emission vehicles. 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 bond strength of the membrane to the catalyst can be improved.

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 the 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 treatment of the GDL in for example a N2-plasma.
The fuel cell with the plasma treated GDL shows significantly higher cell voltages than the reference fuel cell without a plasma treated GDL. This is due to the fact that the membrane runs dry, especially at higher current densities. When using a plasma treated GDL a certain amount of water can be retained in the cell leading to a better fuel cell performance.

Contact Person
Name: Dr.-Ing. Matthias Walker