Composite materials based on polymer-derived SiCN ceramic and disordered hard carbons as anodes for lithium-ion batteries

• Two kinds of new SiCN ceramic/hard carbons composites were synthesized.
• The electrochemical properties for Li-ion battery application were studied.
• The composites show superior properties to pure hard carbons.
• The composites exhibit a high-recovered capacity and long-life durability.
• The composites are suitable for high power energy devices.

New composite materials based on polymer-derived SiCN ceramics and hard carbons were studied in view of its application as anodes for lithium-ion batteries. Two kinds of composites were prepared by pyrolysis of the preceramic polysilazane (HTT1800, Clariant) at 1000 °C in Ar atmosphere mixed with hard carbons derived from potato starch (HC_PS) or with a hard carbon precursor, namely potato starch (PS), denoted as HTT/HC_PS and HTT/PS composites, respectively. Thermal gravimetric analysis suggests possible reactions between the preceramic polymer and the carbon precursor. The HTT/PS composites contain higher amount of oxygen and appear to be more homogeneous than that of the HTT/HC_PS composite. Raman analysis confirms the presence of highly disordered carbon in the composites by the appearance of the well-pronounced D band at 1347 cm−1. The materials are amorphous with a significant fraction of single graphene sheets as confirmed by X-ray diffraction. The HTT/PS composite exhibits a high-recovered capacity (434 mAh g−1 when charging with a current of 36 mA g−1) and outstanding cyclability for 400 cycles even at high current rates (90 mAh g−1 when charging with 3600 mA g−1). These properties make the composite a candidate anode material for high power energy devices.