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

Nanoporous Sn-SnO 2 -TiO 2 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 SnCl 2 and TiCl 3 . The Sn-SnO 2 -TiO 2 composite films, containing a large amount of oxygen and a small amount of Ti (2–16 at.%) in form of TiO 2 , are composed of nanocrystals in the form of dendrites, needles, flakes, or scales, which were dependent predominantly on the mole ratio of [Sn 2+ ]/[Ti 3+ ], but also on the volume ratio of EtOH/H 2 O 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-SnO 2 -TiO 2 composite films formed in plating baths with EtOH/H 2 O 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 TiO 2 , which mitigates the volume change that occurs during the lithiation and delithiation of the Sn nanocrystals.