Coupling Experiment and Modelling to Characterize and Predict Performances of PEMFC
Abstract
In the past few decades, many improvements have been achieved regarding the PEMFCs components,
the cell/stacks design as well as the architecture of the overall system. Hence, the level of maturity of
PEMFC systems recently became sufficient to enable their commercialization for automotive applications
(FCEV Miraï by Toyota, FCEV Nexo by Hyundai, etc.). However, despite great initial performance, PEMFC
systems still suffer technological limitations, such as their initial cost and overall durability in real life
operation, which prevents widespread industrial deployment. Some of these limitations can be overcome
by combining experiments and modelling to characterize and better understand the behaviour of the
carbon-supported platinum (Pt/C) electrocatalyst, its utilization/effectiveness in PEMFC catalyst layers and
to be able to predict the performance and durability of PEMFC. This should help making the most relevant
choices to accelerate the development processes of PEMFC.
In this work, physico-chemical and electrochemical measurements are performed from the scale of the
raw Pt/C materials up to the complete catalyst layer, to gather as much information as possible on the
catalytic layer micro-structure and its operating properties. Coupling experiments in classic RDE and in
PEMFC differential-single cell (1.8 cm² under high reactant stoichiometry) enables to fully characterize the
electrochemical properties and behaviour of our materials. These different measurements are performed
under various ideal and well-controlled operating conditions: cell temperature (T), relative humidity (RH),
partial pressure of O2 (PO2) were chosen to be relevant and to dissociate and characterize as much as
possible the different electro-chemical mechanisms involved in the catalyst layers of PEMFC.
In parallel; several models have been developed to simulate one or combined mechanisms leading to the
performance [1] and degradation of cell components[2], [3]. In fact, models aim at isolating and quantifying
the contribution of each mechanism by choosing relevant operating conditions. Based on our experimental
work and data sets, the behaviour of the Pt/C electrocatalysts has been studied in order to introduce new
electrocatalytic features and especially the Pt surface oxide formation and reduction which is linked to Pt
surface state. This preliminary step was then further developed into, a complete performance model for
the O2 reduction reaction at the cathode to better describe the physical and electrochemical phenomenon
involved in 0D and 1D catalyst layers during fuel cell operation. In this new description, the position of the
main adsorption/desorption peaks are well captured by the simulation compared to experiment keeping
complete physical meaning.