The Interfacial Nature of Mechano-Chemo-Electrical Potential and Its Application to Processing and Failure Prediction in Solid State Lithium Ion Batteries

Abstract

The incorporation of mechanical stresses into descriptions of the electrochemical potential is of fundamental significance in understanding the processing and failure mechanisms in solid state lithium ion batteries. The chemical potential is defined by (i) the nature of the species, e.g. lithium atoms, or ions, and (ii) by the site or the phase where the species reside. The second point draws a distinction between the influence of mechanical tractions applied to a surface or an interface – e.g. grain boundaries – and the volumetric strain energy obtained from solutions to the usual boundary value problems in mechanics. This distinction is great, and not sufficiently recognized in the literature. In this presentation the interfacial mechano-chemo-electrical potential will be described and then applied to three problems in the processing and failure prediction of solid state lithium ion batteries made with Li-metal anodes.