UC San Diego

Enabling the next generation of rechargeable batteries necessitates the fabrication and manufacturing of energy dense electrode materials at scale. Sodium metal is an attractive option because of its abundance and potential cost advantages relative to lithium. As such, sodium-metal has been widely researched as a next-generation anode for rechargeable batteries. However a central issue in sodium-metal research is the lack of a universal sodium source for laboratory experiments. Moreover, its mechanical softness leads to processing difficulty which makes for inconsistent studies. In practice, approaches to prepare anodes at lab scale include rolling sodium onto a current collector from sodium ingots, vendor-supplied sodium chips, and in situ electroplating sodium, each of which introduces different structural and practical uncertainties.This thesis examines sodium-metal sources beyond bulk morphology to determine whether they exhibit crystallographic differences that influence electrochemical behavior. A reproducible cell assembly workflow was first established to reduce variability from externally applied stack pressure. Cryogenic focused ion beam/scanning electron microscopy (cryo-FIB/SEM) showed that ingot-derived, chip-based, and electroplated sodium all appeared dense and morphologically similar at the mesoscale. However, wide-angle X-ray scattering (WAXS) revealed clear source dependent differences in crystallographic texture. Sodium chips were closest to a powder-like pattern, while electroplated and mechanically processed sodium showed increasing preferred orientation. Varying electroplating current density further demonstrated current-density-dependent crystallographic texture. Rate testing showed improved high-rate utilization for electroplated sodium relative to sodium chips, supporting crystallography as a critical variable in sodium-metal electrochemistry.