Here FEC and its reduction products are being studied on different lithium silicide surfaces using density functional theory. The lithium silicide phases under consideration are the crystalline LiSi phase with a low lithium concentration and the crystalline Li15Si4 phase with a higher lithium concentration. All unique low index surface facets are considered for each lithium silicide phase. The interactions of FEC and its dissociation products are analyzed on the different anode surface facets to determine the surface sensitivity of FEC breakdown. From the binding energies of the FEC reactant and the CO2, CH2CHO, and F- products on the lithium silicide surface facets, FEC dissociation reaction energies are calculated. The facet on which SEI formation begins to form is determined from the reaction energies for both the low and high concentration lithium silicide anodes.
This material is based upon work supported by the U. S. Department of Energy, Office of Science, Office of Workforce Development for Teachers and Scientists, Office of Science Graduate Student Research (SCGSR) program. The SCGSR program is administered by the Oak Ridge Institute for Science and Education (ORISE) for the DOE. ORISE is managed by ORAU under contract number DE-SC0014664. Use of the Center for Nanoscale Materials, an Office of Science user facility, is supported by the U. S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under contract number DE-AC02-06CH11357.