SnO2/polypyrrole hollow spheres with improved cycle stability as lithium-ion battery anodes

Abstract

SnO2/polypyrrole (SnO2/PPy) hollow spheres were fabricated by a liquid-phase deposition method using colloidal carbon spheres as templates followed by an in-situ chemical-polymerization route. The obtained SnO2/PPy composite particles had a size of 610–730 nm. The thickness of inner shell (SnO2) and outer shell (PPy) for composites was about 35 and 90 nm, respectively. As an anode for lithium ion batteries, the SnO2/PPy composites electrode showed superior rate capability and excellent long-term cycling performance. After a long-term cycling of 600 cycles at different current densities, a capacity of 899 mAh g−1 was achieved at the current density of 100 mA g−1 for SnO2/PPy composites. The excellent electrochemical performance was attributed to the synergistic effect between the PPy coating layer and the hollow SnO2 spheres, which guaranteed vast lithium storage sites, good electronic conductivity, fast lithium ion diffusion, and sufficient void space to buffer the volume expansion.