Characterization and Electrochemical Performance at High Discharge Rates of Tin Dioxide Thin Films Synthesized by Atomic Layer Deposition

Abstract

In this study, thin films of tin dioxide have been synthesized on substrates of silicon and stainless steel by atomic layer deposition (ALD) with tetraethyl tin and by inductively coupled remote oxygen plasma as precursors. Studies of the surface morphology by scanning electron microscopy show a strong dependence on synthesis temperature. According to the x-ray photoelectron spectroscopy measurements, the samples contain tin in the oxidation state +4. The thickness of the thin films for electrochemical performance was approximately 80 nm. Electrochemical cycling in the voltage range of 0.01–0.8 V have shown that tin oxide has a stable discharge capacity of approximately 650 mAh/g during 400 charge/discharge cycles with an efficiency of approximately 99.5%. The decrease in capacity after 400 charge/discharge cycles was around 5–7%. Synthesized SnO2 thin films have fast kinetics of lithium ions intercalation and excellent discharge efficiency at high C-rates, up to 40C, with a small decrease in capacity of less than 20%. Specific capacity and cyclic stability of thin films of SnO2 synthesized by ALD exceed the values mentioned in the literature for pure tin dioxide thin films.