Electro-Chemo-Mechanical Modeling of Solid-State Batteries

Abstract: Solid-state batteries (SSBs) have recently been proposed as promising alternatives to conventional Li-ion batteries because of their high level of safety and power density. The engineering of SSBs requires comprehensive modeling of their physics and electrochemistry with an emphasis on the interfacial processes, including electrochemical stability and mechanical stresses. In this article, continuum-scale simulations are chosen as the modeling framework to study such properties. A comprehensive continuum model is constructed for the simulation of the electro-chemo-mechanical (ECM) response of an SSB that resolves the bulk transportation of charged species and their interfacial transfer kinetics. It also studies the formation of space charge layers (SCLs) at interfaces and the development of interfacial stresses. The results suggest that the SCLs and the charge transfer kinetics are intertwined. The emergence of the SCLs and the depletion of reactants increases the charge transfer overpotential. We have also studied the coupling between electrochemistry and mechanics at interfaces, the results of which indicate that the strong electric fields originating at interfaces yield significant stresses. We, thereby, highlight the necessity of considering the ECM coupling in the SCLs when modeling an SSB.