Nanoporous Sn-SnO2-TiO2Composite Films Electrodeposited on Cu Sheets as Anode Materials for Lithium-Ion Batteries

Nanoporous Sn-SnO2-TiO2 composite films with large surface areas were fabricated on Cu sheets by a hybrid electroplating method, i.e., electrodeposition and electrophoretic deposition, using an ethanol-water mixed bath containing SnCl2 and TiCl3. The Sn-SnO2-TiO2 composite films, containing a large amount of oxygen and a small amount of Ti (2–16 at.%) in form of TiO2, are composed of nanocrystals in the form of dendrites, needles, flakes, or scales, which were dependent predominantly on the mole ratio of [Sn2+]/[Ti3+], but also on the volume ratio of EtOH/H2O in the plating baths and the current density. The initial specific discharge capacities were 495, 1069, and 772 mAh·g−1 for the nanoporous Sn-SnO2-TiO2 composite films formed in plating baths with EtOH/H2O ratios of 9:1, 6:1, and 3:1, respectively. The enhanced discharge capacity and improved retention of the composite films can be attributed to their nanoporous structure and the inclusion of TiO2, which mitigates the volume change that occurs during the lithiation and delithiation of the Sn nanocrystals.