Foam-like, microstructural SnO2–carbon composite thin films synthesized via a polyol-assisted thermal decomposition method

Abstract

Foam-like, microstructural SnO₂–carbon composite thin films were synthesized by refluxing SnCl₂·2H₂O in ethylene glycol (EG) at 195 °C for 4 h under vigorous stirring in air followed by thermal decomposition of the as-synthesized precursor solution, whereby the products were deposited onto stainless steel (SS) substrates. Subsequently, the decomposed product, which now consists only of the microstructural SnO₂–carbon composite thin film, without the addition of any binder and carbon black conductive agent, was directly applied as an anode material for use in a Li-ion rechargeable battery. Physical and electrochemical characterizations of the as-synthesized thin films were carried out. The foam-like, microstructural SnO₂–carbon composite thin films that undergo thermal decomposition in air at 300 °C demonstrated the best cyclability, delivering a specific discharge capacity of approximately 496 mAh g⁻¹ beyond 100 cycles. We believe that the presence of a uniform, SnO₂–carbon network throughout the foam-like thin film, acts not only as an improved conducting network but also buffered the volume expansion upon Li–Sn alloying, resulting in a much improved cycling of the composite thin film electrode.