A novel nanosized silicon-based composite as anode material for high performance lithium ion batteries

A new kind of silicon-based composite anode with high initial coulombic efficiency and good cycling performance is synthesized by a wet high energy mechanical milling technique and characterized by X-ray diffraction, transmission electron microscope and high resolution transmission electron microscope. It is demonstrated that the in situ formed Si particles with size of 5–10 nm are uniformly distributed in the elastic matrices consisting of the in situ formed Li-containing compounds, amorphous P2O5, SiP2O7, Ni, Si–Ni alloys and conductive graphite. The elastic matrices can effectively alleviate the volume variations of the active Si particles during long-term cycling. The as-prepared silicon-based composite electrode reveals an initial discharge and charge capacity of 549 and 565.3 mAh g−1, respectively, with an initial coulombic efficiency of 103%. After 80 cycles, the reversible capacity of the composite electrode is up to 560.7 mAh g−1 with a capacity retention rate of 99%.