Designing Self-Standing Three Dimensional Composite SiCu Thin Films as Anodes for Lithium Ion Battery.

Three dimensional nanostructured silicon based electrodes are promising for high capacity anodes in lithium ion battery. Though the specific capacity of silicon is very high compared to the conventional graphite anode, its large volume changes in cycling results in poor cycle life, which eventually restricts Si use in commercial applications. This problem could be overcomed by producing selfstanding nanostructures that can provide facile relaxation to prevent electrode pulverization. Plus, nanostructured electrodes maintain effective electrical contacts in cycling and provide short Li diffusion distances improving their electrochemical performances. In this paper, by using electron beam evaporation glancing angle deposition method three dimensional Si based composite (10%at. Cu) self-standing nanostructures with different porosities are produced. After the morphological and structural characterizations, their potential uses as anodes in lithium ion batteries are evaluated by means of electrochemical tests.

Silicon-Copper Helical Arrays for New Generation Lithium Ion Batteries.

The helical array (with 10 atom % Cu) exhibits 3130 mAh g(-1) with 83% columbic efficiency and retains 83% of its initial discharge capacity after 100th cycle. Homogeneously distributed interspaces between the helical arrays accommodate high volumetric changes upon cycling and copper atoms form a conductive network to buffer the mechanical stress generated in the electrode while minimizing electrochemical agglomeration of Si. Also, ion assistance is believed to enhance the density of the helices at the bottom thus increasing the adhesion.

The effect of thin film morphology on the electrochemical performance of Cu-Sn anode for lithium rechargeable batteries.

We investigate the anode performance of non ordered and ordered nanostructured Cu-Sn thin films deposited via electron beam deposition technique. The ordered nanostructured Cu-Sn thin film having nano-porosities was fabricated using an oblique (co)deposition technique. Our results showed that the nano structured Cu-Sn thin film containing Cu-Sn nanorods had higher initial anodic capacity (790 mA h g(-)) than that of the non ordered thin film (330 mA h g(-)). But the capacity of the ordered nanostructured Cu-Sn thin film diminished after the first cycle and a steady state capacity value around 300 mA h g(-) is sustainable in following up to 80th cycle, which is attributed to the composition and morphology of the thin film. The presence of copper containing Sn nanorods leading to form nano-porosities as interstitial spaces among them, enhanced lithium ions movement within thin film and increased the thin film tolerance against the stress generated because of the drastic volume change occurred during lithiation-delithiation processes; hence, homogenously distributed porosities increased the cycle life of the thin film.