==On the interaction between mechanics and chemistry: Two case studies in (i) Lithium Ion Batteries and (ii) Heterogeneous Catalysis==

Chemo-mechanical coupling, i.e., interaction between mechanical fields (stress, strain, …) and chemical phenomena is familiar in a number of problems in mechanics of materials. Examples include stress corrosion cracking, dislocation interaction with its local environment, the role of stress in microstructure evolution in certain alloys, etc. The basic idea is that the contribution of mechanical fields to the free energy and the chemical potential of certain species can tip the energy landscape to influence the chemical reaction rates in ways that may have practical implications. In this talk, we present investigations of chemo-mechanical interactions in the context of two energy technologies: (i) lithium ion batteries and (ii) heterogeneous catalysis. In the former, we demonstrate that the stress in an electrode is coupled to the potential of an electrochemical cell through solution thermodynamics and examine the possible practical implications. In the latter, we examine how externally applied stress fields on a catalyst can influence the catalytic efficiency in the context of oxygen reduction reaction (ORR) and the hydrogen evolution reaction (HER). By isolating elastic strain from the electronic structure effects (the so called-ligand effect), this study provides a better understanding of the processes that control electrocatalytic activity and can guide the design of strained core-shell nano-particle catalysts.