Tomokazu Morita

Nano Si Cluster- SiO x ‐C Composite Material as High-Capacity Anode Material for Rechargeable Lithium Batteries

Nanosilicon cluster-SiO x -C composites including nanosize Si particles were prepared by using the disproportionation of silicon mono-oxide and the polymerization of furfuryl alcohol. The applicability of nanosilicon composites as anode material for rechargeable lithium batteries was investigated on the basis of X-ray diffraction measurement, observation by transmission electron microscopy (TEM) and electrochemical studies. TEM analysis showed that Si clusters in the range of 2-10 nm were distributed homogeneously within silicon oxide phases. The nanosilicon composite anode had a large capacity of ca. 700 mAh/g and a long cycle life of >200 cycles. The improvement of cyclability is due to the nanosize Si particles and their uniform dispersion within the silicon oxide phase retained by the carbon matrix, which could effectively suppress the pulverizing of Si particles by the volume change during lithium insertion and extraction.