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/SiO x /PPY) material was prepared in this paper. The G/SiO x /PPY material has good electrochemical performances including high capacity and cyclic stability. It has 2068/2130[Formula: see text]mAh g[Formula: see text] of capacity after 100th charge/discharge cycle at 200[Formula: see text]mA[Formula: see text]g[Formula: see text] of current density and 575/569[Formula: see text]mAh[Formula: see text]g[Formula: see text] of capacity after 100th charge/discharge cycle at 2000[Formula: see text]mA g[Formula: see text] of current density when G/SiO x molar ratio is 1:5. Its capacity increases but its cyclic stability decreases with G/SiO x molar ratio decreasing from 1:1 to 1:3 and 1:5. The electrochemical performance improvement of the G/SiO x /PPY material is due to the synergetic effect of graphene and polypyrrole, which improve the conductivity of SiO x 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.