Layer-by-Layer Structure Design of G@SiOx@PPY Materials as Promising High-Performance Anodes for Lithium-Ion Batteries

The graphene/silicon oxide/polypyrrole (G/SiOx/PPY) material was prepared in this paper. The G/SiOx/PPY material has good electrochemical performances including high capacity and cyclic stability. It has 2068/2130mAh g(-1) of capacity after 100th charge/discharge cycle at 200mAg(-1) of current density and 575/569mAhg(-1) of capacity after 100th charge/discharge cycle at 2000mA g(-1) of current density when G/SiOx molar ratio is 1:5. Its capacity increases but its cyclic stability decreases with G/SiOx molar ratio decreasing from 1:1 to 1:3 and 1:5. The electrochemical performance improvement of the G/SiOx/PPY material is due to the synergetic effect of graphene and polypyrrole, which improve the conductivity of SiOx and prevent its dropping from the surface of the electrode caused by the stress due to the volume expansion and shrinkage in charge/discharge cycles.