Mechanical Properties and Chemical Reactivity of LixSiOy Thin Films.

摘要: Silicon (Si) is a commonly studied candidate material for next-generation anodes in Li-ion batteries. A native oxide SiO2 on Si often inevitable. However, it not clear if this layer has positive or negative effect the battery performance. This understanding complicated by lack of knowledge about physical properties lithiation products and convolution chemical electrochemical effects during anode process. In study, Li xSiO y thin films as model materials lithiated were deposited magnetron sputtering at ambient temperature, with goal (1) decoupling reactivity from (2) evaluating y. X-ray photoemission spectroscopy analysis demonstrate that composition close to previous experimental reports can be achieved through sputtering. Our density functional theory calculations also confirm possible phases formed lithiating are very measured film compositions. Scanning probe microscopy measurements show mechanical strongly dependent lithium concentration, ductile behavior higher content brittle lower content. The was investigated measuring AC impedance evolution, suggesting continuously reacts electrolyte, part because high electronic conductivity determined solid-state measurements. cycling data sputter-deposited y/Si suggest beneficial stabilizing surface operation, despite its favorable properties.