Electrochemical-mechanical modeling of solid polymer electrolytes: Impact of mechanical stresses on Li-ion battery performance

Davide Grazioli*, Osvalds Verners, Vahur Zadin, Daniel Brandell, Angelo Simone

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

39 Citations (Scopus)
146 Downloads (Pure)

Abstract

We analyze the effects of mechanical stresses arising in a solid polymer electrolyte (SPE) on the electrochemical performance of the electrolyte component of a lithium ion battery. The SPE is modeled with a coupled ionic conduction-deformation model that allows to investigate the effect of mechanical stresses induced by the redistribution of ions. The analytical solution is determined for a uniform planar cell operating under galvanostatic conditions with and without externally induced deformations. The roles of the polymer stiffness, internally-induced stresses, and thickness of the SPE layer are investigated. The results show that the predictions of the coupled model can strongly deviate from those obtained with an electrochemical model—up to +38% in terms of electrostatic potential difference across the electrolyte layer—depending on the combination of material properties and geometrical features. The predicted stress level in the SPE is considerable as it exceeds the threshold experimentally detected for irreversible deformation or fracture to occur in cells not subjected to external loading. We show that stresses induced by external solicitations can reduce the concentration gradient of ions across the electrolyte thickness and prevent salt depletion at the electrode-electrolyte interface.
Original languageEnglish
Pages (from-to)1122-1141
Number of pages20
JournalElectrochimica Acta
Volume296
DOIs
Publication statusPublished - 2019

Keywords

  • Battery performance
  • Electrochemical-mechanical coupling
  • Mechanical properties
  • Partial molar volume
  • Solid polymer electrolytes

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