Carbon-doped tin oxide films fabricated by pulse DC magnetron sputtering using CO2 as reactive gas and their application as anodes in lithium-ion batteries

Abstract

Abstract Traditional reactive gas O2 was replaced by CO2 to fabricate carbon-doped tin oxide (SnOx-C) using pulse direct current magnetron sputtering (pDC-MS) with different Ar/CO2 flow ratios, the physical and electrochemical properties of SnOx-C films were characterized by X-ray reflection (XRR), X-ray photoelectron spectroscopy (XPS), battery tester, et al. The results showed that CO2 gas would be decomposed into C and O atoms by Ar+ bombardment, the sputtered Sn particles were oxidized by O atoms and the C atoms were introduced simultaneously in the form of interstitial atoms. All properties of the films changed orderly with the increase of CO2 flow ratios and the sputtering atmosphere of Ar/CO2\xa0=\xa018/12 corresponded to one turning point, moreover, the films deposited with high CO2 flow ratios (CO2\xa0≥\xa012 sccm) showed an improved cycle performance contrasted with the films deposited with low CO2 flow ratios (CO2\xa0≤\xa07 sccm) or the pure SnOx films without carbon-doped. The composition of SnO1.64-C film with the maximum carbon content of 6.1% was obtained by the sputtering condition of Ar/CO2\xa0=\xa015/15, it possessed an extra capacity of ~80 mAh/g compared with that of SnOx film and delivered a stable discharge capacity of 483.3 mAh/g, retention rate of 77.7% in the 50th cycle at a constant current density of 44\xa0μA/cm2.