MEMEPhys model

MEMEPhys model algorithmic structure.The figure describes feedback between instantaneous performance and aging prediction of durability. 

Multi-scale ab initio-based MEMEPhys model... 

The corresponding atomistic kinetics is then implemented into the nonequilibrium nanoscale MEMEPhys models collecting all the elementary events, catalytic and no-catalytic, to simulate the electrochemical observables. The nanoscale models introduce the electric field effect correction without empirical parameters and open interesting perspectives to scale up atomistic data into macroscopic models in a robust way. The impact of the catalyst chemistry and nanostructure on the electrodes and cell potentials can be then captured. 

In 2002 I have invented a transient, multiscale and multiphysics single fuel cell model, called MEMEPhys. This model, that 1 have continuously developed since then, accounts for the coupling between self-consistent physical-based mechanistic descriptions of the PEM and the CL phenomena (e.g. reactants, water and charge transport and detailed electrochemistry) and different materials aging mechanisms [59, 205-215], The model is designed for simulating hydrogen-feed PEMFC, PEM Water Electrolyzers and Li Ion batteries, but could be easily extended to simulate DAFCs. 

Material Degradation Prediction In 2002, Franco has invented a multiscale modeling approach (and an associated simulation package originally called MEMEPhys) dedicated to the simulation of PEM fuel cells (PEMFCs) (Fig. 12) but, later, extended for the simulation... 

A recent extension of this simulation package has been recently reported by Franco [2, 41, 43], called MS LIBER-T (Multiscale Simulator of Lithium Ion Batteries and Electrochemical Reactor Technologies). This model constitutes a breakthrough compared to the previously developed simulation package MEMEPhys penalized by its dependence on commercial software toolboxes and solvers such as Simulink. MS LlBER-T is coded on an independent C/Pyth(Mi language basis, highly flexible and portable (it can eventually be coupled to... 

In the following we discuss in a general way the key concepts supporting the multi-scale model MEMEPhys . For full mathematioal details, the author invites the readers to refer to his group publications. " ... 

From an algorithmic point of view, the multi-scale kinetic model MEMEPhys is supported on two interacting cores (Fig. 11.8) ... 

For example, within this context, CGMD simnlations have been used to build up a stmctural database for CLs with different carbon contents in terms of interpolated mathematical functions describing the impact of the carbon mass loss (induced by corrosion) on the evolution of the ionomer coverage on Pt and carbon, the electronic conductivity of the CB, the effective O2 diffusion properties, the carbon surface area and the Pt surface area (which re-organizes during the carbon corrosion process) (see Fig. 11.9, 11.12). These functions are then integrated into the MEMEPhys kinetic model to simulate the impact of carbon corrosion on the MEA performance decay. ... 

The processes occurring at the interface between the catalyst and electrolyte are manifold and strongly influenced by the surrounding environment and the external parameters (temperature, pressure and electrode potential). In addition, these external parameters can affect the morphology and composition of the CL, especially in cases where nanoparticles are used as catalyst materials. A consistent theoretical description of such complex catalytic systems is a real challenge. We have proposed a novel model within a continuum framework to describe in a detailed way the electrochemical interface at the vicinity of the catalyst under non-equilibrium conditions.This nanoscale model, which is a key part of MEMEPhys , comprises a ID-dififiise layer sub-model and a ID-inner layer submodel, as represented in Fig. 11.13. 

The impact of the chenustry and nanostmctural properties of the catalysts on PEMFC performance can be easily captured by using MEMEPhys if the appropriate thermodynamic and/or ab initio DFT data are available. Figure 11.14 shows the modelling calculation results of the ORR activity of pure Pt compared... 

An ab m/ho-based kinetic model that is able to describe the performance of a PEMFC anode underthe influence of CO+H2 was developed within MEMEPhys . The results have shown that the PtjCo catalyst has a higher CO tolerance than pure Pt. 

Fitrther development of MEMEPhys is still necessary to include descriptions of other realistic phenomena such as mechanical stresses and non isothermal operating conditions. Moreover, analytical approximations are certainly of interest within the perspective of implementing this kind of models in PEMFC stacks arrd systems, and this is also an area for closer examination. Further exterrsion of MEMEPhys to other electrocherrrical systenrs, such as electrolyzers and batteries is also possible, as recently demonstrated by the author s group. ... 

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