In Situ Strain Measurement in Solid-State Li-Ion Battery Electrodes

Volumetric changes occur in electrodes of rechargeable Li-ion batteries during charge-discharge cycles. In solid-state batteries, the resulting strains cause mechanical degradation of the electrodes, solid electrolyte (SE) and/or SE-electrode interface due to the presence of brittle interfaces as well as mechanical constraints. Here, we investigate the chemo-mechanical response in working electrodes of solid-state Li-ion batteries. In situ strains are measured by full-field optical Digital Image Correlation (DIC) in a high stiffness oxide solid electrolyte, LAGP, along with a model Au working electrode during cyclic voltammetry. Mechanical deformations are correlated with electrochemical performance and damage mechanisms. The measured strains are large enough to induce cracking in the solid electrolyte. Moreover, we show the chemo-mechanical strains developed in electrodes of a solid-state battery are less reversible than those of liquid electrolyte batteries.