Carbon-rich SiOC anodes for lithium-ion batteries: Part I. Influence of material UV-pre-treatment on high power properties

Polymer-derived carbon-rich SiOC ceramics were studied in view of its application as anode material for lithium ion batteries. The samples were prepared at 1100 and 1300 °C by direct precursor pyrolysis or by a UV-radiation supported crosslinking applied before the thermal treatment. By means of various characterization techniques (Raman spectroscopy, X-ray diffraction, and elemental analysis) we found out that the UV-crosslinking procedure preceding the thermal treatment significantly influences the amount as well as the structural and electrochemical properties of the resulting carbon phase. The strong impact of those properties on the lithium insertion capacity and high current capability was analysed. The crosslinked sample prepared at 1100 °C revealed a stable reversible capacity of more than 650 mAh g− 1 for lower currents and more than 80 mAh g− 1 when a charge/discharge current of 4000 mAg− 1 is used. The extended cycling with high current does not lead to sample damage and the initial capacity is recovered when lower currents are applied after the high current charging/discharging procedure. We attribute these excellent properties of the crosslinked sample prepared at 1100 °C to the particular disorder of the carbon phase portioned in situ from the SiOC matrix under these conditions.