Indexed on: 22 Jul '16Published on: 16 Jul '16Published in: Journal of Alloys and Compounds
A novel core-shell structured graphite/silicon@pyrolyzed-carbon (G/Si@C) composite was fabricated with a scalable and cost-effective method, including the processes of mechanical milling, spray drying, pitch coating and pyrolysis. The active silicon particles obtained by mechanical milling show an average size of 126 nm and exhibit a uniform dispersion on the skeleton consisting of graphite. The graphite provides sufficient electrical conductivity and mechanical strength for the G/Si@C composite, and the amorphous carbon coating layer is beneficial for buffering the volume change of Si and producing a stable SEI film. As a negative electrode material of lithium-ion battery, the synthesized G/Si@C composite has excellent structural stability and electrochemical performance. The G/Si@C composite with 15.7 wt % silicon shows a high reversible capacity of 637.7 mAh g−1 with an initial efficiency of 77.9%, the capacity retention is 89.5% after 100 cycles.