Corrosion of Electrochemical Energy Materials: Stability Analyses Beyond Pourbaix Diagrams

Abstract

Since their first appearance, electrode potential/solution pH charts (Pourbaix diagrams) have served as a general framework for the analysis of material corrosion in aqueous solutions. Their utility in describing electrochemical stability of materials is rooted in the equilibrium thermodynamics based formalism. Electrochemical energy systems, however, do not always operate under thermodynamic equilibrium conditions, and corrosion itself is an inherently irreversible interfacial process. In this Perspective, we highlight a number of representative studies drawn primarily from (photo)electrocatalysis research and aimed to account for the effects of potentiodynamic polarization and transient dissolution, interfacial electrochemical reactions, formation and stability of metastable phases, strain-induced corrosion, as well as the kinetics of dissolution and phase transformations. Some theoretical approaches that can help disentangle corrosion mechanisms under conditions relevant to electrochemical energy conversion applications are briefly discussed. We also advocate for more research efforts directed at the basic science of electrochemical corrosion that has long been deemed as a not “fancy” topic.