Electrochemical Properties of Si Film Electrodes Grown on Current Collectors with Reduced Cu2O Nanostructures for Li Ion Battery

Abstract

Si film electrodes were fabricated on surface-modified Cu current collectors (foils) by using an oxidation-reduction process and their electrochemical properties were investigated with various preoxidation times of 1, 3, and 6 h. The reduction of the preoxidized Cu foil formed Cu2O for 1 hand 3 h-preoxidized Cu foils and Cu for 6 h-preoxidized Cu foil as the reductive products on the surface, leading to the changes in the shape of nanostructures and to the decrease in the surface roughness. The Si film electrode with 1 h- and 3 h-preoxidized Cu foils exhibited the rapid capacity fading due to the presence of Cu2O. The Si film electrode with the 6 h-preoxidized (fully reduced) Cu foil demonstrated the good cycle performance, since the coral-like Cu nanostructures enhanced the adhesion with the Si film and the structural stability of the Si film electrode during the electrochemical reaction.