PEMFC stack is assembled by connecting each single cell in series,
which consists of membrane electrode assembly, gas diffusion
layer, gaskets, and bipolar plates with flow channels for reactant
gases. In general, one PEMFC stack contains several tens to even
several hundreds of single cells, depending on the designed power
of the stack. For each cell, gaskets or seals have to be used around
the perimeters to prevent the leakage of reactant gases from the
active area. If any seal or sealing material degrades during fuel cell
operation, a leakage leading to mixture of reactant gases can occur.
This will not only affect the performance of fuel cells and the utilization
of fuel gases, but may also bring the danger of burning from
the mixture of hydrogen and oxygen (air). Thus, the stability and
durability of sealing materials are of great importance for fuel cell
applications.