Near zero-strain silicon oxycarbide interphases for stable Li-ion batteries

Abstract

Silicon oxycarbide, as confirmed by in situ TEM, exhibits near-zero volume expansion strain during lithiation, resulting in reduced electrolyte uptake.

Topological Considerations in Electrolyte Additives for Passivating Silicon Anodes with Hybrid Solid–Electrolyte Interphases

“…Silicon is a high capacity anode that on its own or as part of a composite with graphite substantially increases the energy density of lithium-ion batteries. − Unlike graphite anodes, however, silicon anodes rarely form long-lasting solid-electrolyte interphases (SEI), which ultimately shortens their cycle life. , Underlying this instability is the magnitude of volume changes (up to 300%) that occur during lithiation and delithiation with changes in state-of-charge (SOC), which triggers SEI delamination, reconstruction, and in some cases dissolution. − As a result, the electrolyte is continuously degraded, causing a permanent loss of the Li inventory. To better accommodate volume changes in silicon anodes, while maintaining adequate ion conduction and electronic passivation, hybrid SEIs incorporating inorganics and organics are considered essential, , yet challenging to control from a chemomechanical perspective through electrolyte design.…”