Silicon\nOxycarbide Beads from Continuously Produced Polysilsesquioxane as\nStable Anode Material for Lithium-Ion Batteries

Abstract

Silicon\noxycarbides are promising anode materials for lithium-ion batteries.\nIn this study, we used the continuous MicroJet reactor technique to\nproduce organically modified silica (ORMOSIL) spheres which were pyrolyzed\nto obtain silicon oxycarbides. The continuous technique allows the\nproduction of large quantities with a constant quality. Different\nalkoxysilanes were used to produce the silicon oxycarbides with different\ncompositions. Thereby, the amounts of silicon–carbon bonds,\nas well as the free carbon content, were modified. Electrochemical\ntesting was carried out in 1 M LiPF₆ in ethylene carbonate/dimethyl\ncarbonate. A mixture of vinyl- and phenyltrimethoxysilane was identified\nas the best anode material with a stable performance due to the increased\ncarbon content. The first-cycle delithiation capacity of the most\nstable material was 922 mA h/g, and the capacity retention after 100\ncycles was 83% (767 mA h/g).