SiCN/C-ceramic composite as anode material for lithium ion batteries

The choice of electrode and electrolyte materials to design lithium batteries is limited due to the chemical reactivity of the used materials during the intercalation/deintercalation process. Amorphous silicon carbonitride (SiCN) ceramics are known to be chemically stable in corrosive environments and exhibit disordered carbonaceous regions making it potentially suitable to protect graphite from exfoliation. The material studied in this work was synthesized by mixing commercial graphite powder with the crosslinked polysilazane VL20®. Pyrolysis of the polymer/graphite compound at appropriate temperatures in inert argon atmosphere resulted in the formation of an amorphous SiCN/graphite composite material. First electrochemical investigations of pure SiCN and of the SiCN/C composite are presented here. A reversible capacity of 474 mA hg−1 was achieved with a sample containing 25 wt% VL20® and 75 wt% graphite. The measured capacity exceeds that of the used graphite powder by a factor of 1.3 without any fading over 50 cycles.