(Invited) Continuum Mathematical Modeling of Water Electrolysis: A Tutorial

Widespread use of hydrogen energy is contingent on the development reliable and economical sources hydrogen. Electrolysis from renewably-derived low-carbon electricity a potentially viable method generation. Prime among electrolysis technologies are those utilizing ion-conducting polymers (ionomers) including proton-exchange-membrane water electrolyzer (PEMWE). However, these need to exhibit increased efficiency, performance, durability become commercially viable. Like most electrochemical devices, PEMWEs involve multiple components (e.g., catalyst, ionomer, transport layers, membrane, plates) phases, with phenomena occurring across different time length scales. Furthermore, it difficult experimentally probe many species during operation. Thus, mathematical modeling at continuum level has been an invaluable aid in exploring, understanding, optimizing PEMWE cell components. This especially true highly coupled complex physics chemistries that occur membrane-electrode assembly (MEA). The typical volume-averaged non-isothermal model include multiphase porous media, concentrated-solution theory, Ohm’s Law, Butler-Volmer kinetics, ion, gas, ionomer. In this talk, approaches, governing equations, constitutive relationships will be described, benefits limits modeling. While focus equations macroscale effects, detailed submodels approaches for scaling full cells specific components, respectively, introduced. For example, as shown Figure 1, one can perform applied voltage breakdown describe mechanisms resulting necessary overpotentials, which useful identifying opportunities improving performance by quantifying potential losses associated mechanism. generation such analysis discussed various approaches. Also 1 how used elucidate safety concerns identify issues resolved, case, nonlinear crossover. Finally, future directions multiscale multi-model coupling discussed.