Sodium-ion batteries (SIBs) gained a high attention in the last years for energy storage applications because of the limited lithium resources and the intention to use widely abundant and sustainable materials paving the way toward greener, more sustainable, and lower-cost energy storage. Contrary to lithium-ion batteries (LIBs), graphite is not sufficient anode material for Na-ion intercalation due to its low interlayer space distance. The development of new anode materials which have better sodiation capability is one of the key points to produce NIBs on commercial scale. Among others the chemically and structurally stable silicon oxycarbide-based ceramic materials are a good candidates as supports for anodes. In this work SiOC-based porous anode was prepared from cross-linked (1200°C/1 h) and pyrolysed Polyramic polysiloxane. The final powder was characterized by means of phase composition, elemental analysis and particle size.
The pyrolysed SiOC powder and conductive carbon C65 were milled in a tungsten carbide planetary ball mill to obtain homogenous powder mixture. Water based slurry was prepared and cast onto copper foil. The anode composition was adjusted to 80:10:10 for active material : conductive carbon : binder. The cells were assembled using Na metal as counter electrode.  NaPF6 and/or NaFSI in EC/DMC (50:50) solution was used as electrolyte. Galvanostatic charging/discharging was carried out in the voltage range of 0.005 - 2.5 V at room temperature between 0.25 A/g and 2 A/g current density. Both electrodes reached a specific discharge capacity 160-170 mAh/g after 60 cycles. Cyclic voltammetry was performed to observe the redox peaks in the voltage range of 0 - 2.5 V at room temperature with the scan rate of 0.05 mV/s. Moreover, also the SiOC/tin ceramic-metal nanocomposite as anode matrix and modified alginate-based binders were tested under the same conditions.
The work was supported by the Horizon 2020 project “SIMBA” No. 963542 and the Slovak grant agencies APVV-19-0461 and VEGA 2/0167/22.