Si and SiCu three dimensional sculptured films as negative electrodes for rechargeable lithium ion batteries

Three dimensional sculptured Si films with (10 %at.) and without Cu contents have been fabricated by an ion-assisted glancing angle co-deposition technique. Once the morphological and structural differences depending on Cu contents of the films have been evaluated, their uses as anodes in lithium ion batteries have been also discussed. The morphological analyses demonstrate that Cu presence improves nano ordering and the homogenity along the nano sculptured structure. The galvanostatic tests show that the film without Cu fails quickly, but the one with 10%at. Cu content delivers 800 mAh g^-1 with 99% coulombic efficiency after 100^th cycles. It is believed that the composite electrode has a better electrochemical performance because Cu plays a crucial role in holding the electrode together, buffering the mechanical resistance and enabling faster electron transfer.