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

摘要

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 P_2O_5, SiP_2O_7, 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%.