Testing & Analysis Techniques

Operando Photoelastic Stress Measurements In Solid Electrolytes PROBING DENDRITEINDUCED STRESSES BY PHOTOELASTIC MEASUREMENT Measuring the stress fields within ceramic solid electrolytes can be challenging due to their brittle nature and the difficulty of obtaining a direct measurement. Researchers from Brown and MIT have developed a novel method for directly measuring the stress fields around dendrites in operando solid state batteries via photoelasticity. The measurement relies on measuring through-thickness-averaged retardance of polarized light passed through a translucent LLZTO disk. The change in retardance can be mapped to a change in stress states to generate an in operando map of the stress states at the dendrite tip. This measurement mode allows for the first direct observation of the stresses around dendrites as they grow. The stress values measured match with those expected from dendrite propagation. Additional modeling was performed via Abaqus to account for outside effects such as Poisson contractions.

Photoelastic stress measurements allow for direct measurement of dendrite tip stress-fields in an operando solid state battery.

Source: Athanasiou, Fincher, Gilgenbach, Gao, Carter, Chiang, Sheldon

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