Optical in situ observation of lithium-ion battery electrodes for material characterization : P1-28

Abstract

In situ methods are particularly beneficial for material characterization and research, due to their physical and chemical access. Our in situ video microscopical setup enables a direct optical observation of positive and negative battery electrodes during charge and discharge. Thereby, ion dynamics can be clearly seen as intercalation front, which is caused by a varying local state of charge (SoC) of the electrodes. The local SoC is seen as change in color or brightness. The latter is used to calculate apparent diffusion coefficients for an entire battery electrode via Fick's second law of diffusion. The diffusion coefficient is useful for the understanding of the overall electrical behavior of the battery and is aditionally required to design and simulate battery cells as well as to design future lithium ion chemistries.