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Description
Silicon anodes for lithium ion batteries (LIBs) exhibit a high theoretical capacity of 3590 mA h g$^{-1}$ – one magnitude higher than commonly used graphite – but they suffer a large volume expansion of around 300 % during cycling. The formation and composition of the solid electrolyte interface (SEI) in LIBs has a huge impact on the stability and performance of the cell. Coatings of only 10 nm have a large influence on the SEI and therefor on the stability of the silicon based anode, hence also the cell.[1] Static time-of-flight neutron reflectometry (TOF NR) measurements proof the first three cycles sufficient to form the SEI using metallic lithium as counter electrode. Carbon or TiO$_2$ surface coatings on Si$_{85}$Ti$_{15}$ alloy anodes significantly influence the composition and thickness of the SEI. In-operando TOF NR measurements during cycling lead to a better fundamental understanding of the formation and growth of the SEI on these high-performance LIB anodes.
References
(1) Xie, H.; Sayed, S. Y.; Kalisvaart, W. P.; Schaper, S. J.; Müller-Buschbaum, P.; Luber, E. J.; Olsen, B. C.; Haese, M.; Buriak, J. M. Adhesion and Surface Layers on Silicon Anodes Suppress Formation of c -Li 3.75 Si and Solid-Electrolyte Interphase. ACS Appl. Energy Mater. 2020, 3, 1609–1616.
