Synergistic effect of graphene and polypyrrole to enhance the SnO2 anode performance in lithium-ion batteries

In this work, a synergistic effect of reduced graphene oxide (rGO) and polypyrrole (PPy) was studied in terms of their promotional role to enhance the capacity and cyclic stability of hollow SnO2 anodes in lithium-ion batteries. The core–shell structured hollow SnO2/rGO/PPy nanocomposites were synthesized using a hydrothermal method followed by an in situ chemical-polymerization route. Substantially improved cycling stability and rate capabilities are achieved on the SnO2/rGO/PPy ternary anodes. The exceptional cycling performance is due to the hollow ternary core–shell structure covered with PPy buffer layers along with the graphene frameworks further benefiting Li diffusivity and electrical conductivity. The significantly increased Li diffusion coefficient improves rate performance and the large current charge and discharge. Thus, taking all of these benefits together including the hollow structures of SnO2 particles, role of the buffer of PPy, and effective matrix of graphene, the ternary nanocomposites yield a robust architecture for anode materials in high-performance Li-ion batteries.