Flexible Free-Standing Tin-Based Carbon Nano Tube Composite Anodes for Li-Ion Batteries

In this study, tin/tinoxide/multi walled carbon nano tube (Sn/SnO₂/MWCNT) composite anodes produced as flexible and free-standing. MWCNT papers (buckypapers) were prepared by vacuum filtration from oxidized MWCNTs with controlling porosity. Double phase Sn/SnO₂ structure was deposited onto buckypapers by thermal evaporation and subsequent plasma oxidation. The ratio between metallic tin (Sn) and tinoxide (SnO₂) was controlled with plasma oxidation time. It was determined that the evaporated pure tin nano crystals were mechanically penetrated into pores of buckypapers to form functionally gradient nanocomposites.  Structure and morphology of the composite anodes were investigated by field emissions scanning electron microscopy (FE-SEM), transmission electron microscopy and X-ray diffractometer. In addition the discharge/charge test, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were carried out to characterize the electrochemical properties of these composites as anode materials for ultra-thin and flexible batteries.