Katerina Aifantis

Abstract:

Si is the most promising anode for Li-ion batteries, as it allows for a capacity that is 10 times greater than that of commercially used graphite. The limiting factor in commercializing it, however, is the severe fracture it experiences from the first electrochemical cycle, which reduces the capacity over 50% after the first few cycles. A new type of microstructure is presented here that can inhibit fracture in Si anodes by patterning the Si surface with microcones which have a nano-porous surface. Such microstructures did not exhibit the typical dry-bed fracture that Si films exhibit from the first electrochemical cycle, and retained their structural stability for twenty cycles. Furthermore, a very thin solid electrolyte interface layer was observed. To understand this unique behavior a multi physics model is developed that can capture the behavior of continuous and patterned Si films, by considering stress-assisted diffusion.