Use of amorphous tin-oxide films obtained by spray pyrolysis as electrodes in lithium batteries

Amorphous tin-oxide films were prepared by spray pyrolysis of SnCl2·2H2O mixed with CH3–COOH and deposited onto a stainless steel substrate at mild temperatures (350°C). The films grown were characterized by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy with energy-dispersive X-ray analysis (SEM-EDX). Also, they were tested as electrodes in lithium rechargeable batteries. The XPS results suggest that the substrate is thoroughly coated and that the films are composed mainly of SnO and SnO2. These films exhibit good charge–discharge properties over more than 100 cycles. Heating at 600°C causes significant changes in their surface composition, in the virtual disappearance of the tin component and in the presence of oxygen-bound Fe. Under these conditions, the reversible capacity dramatically fades and the cell behaves similarly to that made from uncoated substrate.