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Abstract
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Fuel cells, as an energy conversion device for direct and effective conversion of the chemical
energy of a fuel and oxidant into electrical energy, are on the verge of competing with fossil fuels
and other energy sources to produce clean electricity in a variety of sectors. Due to their high
efficiency of energy conversion, quick start-up, simple design, low working temperature and
compatibility with the environment, proton exchange membrane (PEM) fuel cells have attracted
enormous attention among the different types of fuel cells. However, the widespread
commercialization of PEM fuel cells for vehicles is still limited due to their cost, performance, and
durability, among which fuel cell durability is the most challenging aspect [1].
The gas diffusion layer (GDL), which usually consists of a macroporous substrate and a
microporous layer, is inserted between the catalyst layer and bipolar plate of the PEM fuel cell and
has multifaceted roles, such as supplying gaseous reactants homogeneously to the electrode’s
active area, removing the formed water out of the cell, electrically connecting the electrode to the
bipolar plate and providing mechanical support to membrane electrode assembly. Indeed, it has
been largely proved that using GDLs significantly improves device performance [2].
The degradation of various components of PEM fuel cells has been extensively studied so far.
However, the GDL has rarely been examined. Thus, understanding the process of GDL degradation
is essential for successful fuel cell commercialization. As presented in Fig. 1, GDL degradation
can be classified into mechanical and chemical degradation [3].
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