Open AccessStructural and Morphological Analysis of the First Alloy/Dealloy of a Bulk Si–Li System at Elevated Temperature
Author(s) -
Matthew Lefler,
Junghoon Yeom,
Christopher Rudolf,
Rachel Carter,
Corey T. Love
Publication year - 2022
Publication title -
acs omega
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.779
H-Index - 40
ISSN - 2470-1343
DOI - 10.1021/acsomega.2c01145
Subject(s) - materials science , electrode , lithium (medication) , molten salt , electrolyte , alloy , silicon , nanomaterials , carbon fibers , nanotechnology , raw material , wafer , thermal expansion , scanning electron microscope , chemical engineering , composite number , metallurgy , composite material , chemistry , medicine , organic chemistry , engineering , endocrinology
There have been tremendous improvements in the field of Si electrode materials, either by nanoscale or composite routes, and though silicon-containing carbon electrode materials have begun to penetrate the marketplace, the commercial capacities achieved by these cells still fall short of the promise of high capacity Si electrodes. Enabling a cheaper feedstock of Si in the bulk form would make this technology more accessible, though there are many challenges that must be overcome. Whereas other methods utilize nanomaterials and composites to overcome volume expansion and pulverization of a Si electrode, this study explores a thermal route to enable the use of carbon-free bulk Si. To accomplish this, a modified Swagelok cell has been constructed to accommodate high temperatures, corrosive molten salt electrolytes, and a molten lithium electrode to study lithiation of a bulk Si wafer at 250 °C. Scanning electron microscopy, X-ray diffraction, and microcomputed tomography were used to examine morphological and structural changes within the Si upon lithiation and delithiation. It was discovered that semiordered Li x Si phases were formed upon lithiation in molten LiTFSI electrolyte at 250 °C, and the higher temperature does not completely mitigate pulverization of the bulk Si electrode.