Designing self-standing silicon-copper composite helices as anodes for lithium ion batteries

In this study, we have fabricated helical thin films to be used as an anode material in lithium ion batteries (LIB). The thin films having various Cu-Si atomic ratios (30-70%, 20-80%, and 10-90%) are prepared by using ion-assisted glancing angle co-deposition. Cu plays a crucial role in holding the electrode together, minimizing overall capacity loss and enabling faster electron transfer thus, improving the electrochemical performances of the electrodes. Increasing the Cu/Si atomic ratio affects the structure of the helices and their alignment. Implementing ion assisted deposition at the beginning of the film deposition helps to improve film adhesion. The Si-20 at.% Cu anode delivers 1885 mAh g^-1 initially with 98% coulombic efficiency and retains 77% of the capacity after 100 cycles at 100 mA g^-1.