Novel spherical microporous carbon as anode material for Li-ion batteries

Hard carbon spherules (HCS) with micropores were prepared by a hydrothermal method. It has perfect spherical morphology, controllable monodisperse particle size and smooth surface. XRD and Raman spectra show that HCS is nongraphitizable. The reversible capacity of HCS is about 430 mA h/g in using as anode material for lithium ion batteries, and the cyclic performance of HCS is excellent. The kinetic characteristics of HCS are better than MCMB. In addition, the Coulombic efficiency of HCS has been improved by surface modifications such as CVD of acetylene and coating of tetraethoxysilane (TEOS) on the surface of HCS. Furthermore, pinning of the nanosized SnSb alloy particles on the surface of HCS hinders the electrochemical aggregation of alloy particles effectively during charge/discharge cycles. Consequently, the cyclic performance and reversible capacity are much enhanced.