Improving Li/Solid Electrolyte Interfacial Contact and Performance By Evaporating a Conformal Lithium Layer

Tuesday, 3 October 2017: 11:30
National Harbor 1 (Gaylord National Resort and Convention Center)
S. Frisco and J. Whitacre (Carnegie Mellon University)
In solid polymer electrolyte/lithium metal based batteries, the interfacial integrity of the lithium metal/polymer interface is critical, and the imperfect, non-uniform initial contact of lithium foil pressed into electrolyte worsens with cycling. This leads to increased impedence at the interface and declining cell performance. To address this issue, we are assessing the impact of depositng a conformal layer of lithium via evaporation onto the electrolyte surface prior to the application of a lithium foil bulk electrode. This approach yields initially enhanced interfacial area due to the improved contact from this conformal coating, which should lead to improved cycling behavior. Electrochemical data in the form of galvanostatic cycling and electrochemical impedence spectroscopy will be discussed in the context of nano-resolution X-ray radiographs and SEM. Data from commercial and lab created solid electrolytes, including PEO and other polymer electrolytes will be shown. Discussed will be the relative performance of solid-state lithium metal cells with a simple lithium foil anode versus a combined lithium evaporated layer/lithium foil anode. Furthermore, the propensity for dendritic failures in PEO electrolyte systems will be examined.