Morphology-stable silicon-based composite for Li-intercalation

Combination of one high energy mechanical milling (HEMM) step between two thermal pyrolysis reactions may provide a novel design for producing the silicon/disordered carbon composite, in which multiphase Si–C cores are homogeneously distributed within the pyrolyzed carbonaceous matrix. The composite offers a large reversible capacity at ca. 900 mA h g−1 within 40 cycles and a relatively high initial coulombic efficiency at ca. 80%. The Li-intercalation degree has a great influence upon the cycle life of the composite. Research revels that both the thermal pyrolysis reaction and the HEMM process give the important contribution to the significantly improved morphology stability. The electrochemical properties of the silicon/disordered carbon composite are superior to those of silicon-based hosts such as SiMg2, Si2Ni and SiO1.1. Moreover, the thermal stability of the silicon/disordered carbon composite under lithiation has been investigated to compare with that of the commercial graphite.