Rate dependent heterogeneities in batteries

Abstract

Batteries represent a dominant technology in energy storage. Due to their widespread deployment in applications ranging from commercial electronics and electric vehicles to grid scale energy storage, these devices continue to be a major focus of research interest; as applications continue developing, batteries are subjected to increasing demands related to energy density and power density.

This dissertation explores three different battery chemistries, with an emphasis on understanding cell performance under the constraints of these increased energy and power demands. In the case of alkaline and Li-ion batteries, x-ray techniques are leveraged to investigate spatial heterogeneities within cells and provide insights on how those internal gradients affect overall cell performance at increased current densities. For Li-metal cells, relevant for realizing batteries with improved energy density, those same x-ray techniques are insufficient for characterizing lithium metal electrode degradation; instead, operando pressure monitoring correlated with differential capacity analysis is presented as a means to probe structural changes within the cell.