Evolution of stress within a spherical insertion electrode particle under potentiostatic and galvanostatic operation

Abstract

Lithium ion battery electrode materials generally experience significant volume changes during charging and discharging caused by concentration changes within the host particles. Electrode failure, in the form of fracture or decrepitation, may occur as a result of a highly localized stress, strain energy, and stress cycles over time. In this paper, we develop analytic expressions for the evolution of stress and strain energy within a spherically shaped electrode element under either galvanostatic (constant current) or potentiostatic (constant potential) operation when irreversible phenomena are dominated by solute diffusion resistance within host particles. We show that stresses and strain energy can evolve quite differently under potentiostatic vs. galvanostatic control. The findings of this work suggest the possibility of developing new battery charging strategies that minimize stress and strain energy and thus prolong battery life.