Spherical CoS(2)@carbon core-shell nanoparticles: one-pot synthesis and Li storage property.

Well-defined spherical CoS(2)@carbon core-shell nanoparticles, with an average diameter of 40 nm and thin graphite shell of 4 nm, were synthesized by the one-pot method in the presence of NaN(3) in supercritical CS(2) at 600 °C using cobaltocene as the cobalt source. The obtained product was characterized by XRD, Raman, FESEM, TEM and HRTEM and the possible formation mechanism was proposed here. Due to the good electronic conductivity and buffering matrix effect of graphitic carbon shells, the CoS(2)@carbon core-shell nanocomposite exhibited highly reversible capacity, good cycle performance and high Coulombic efficiency in lithium ion storage and retrieval, which makes it promising as an attractive anode material candidate for lithium ion batteries.