Silicon and silicon–copper composite nanorods for anodes of Li-ion rechargeable batteries

We investigate the anode performance of Si-based nanorods by tuning its composition using an oblique (co)deposition technique. Our results show that pure Si nanorods have a higher initial anodic capacity of 1500 mAh g−1, but the capacity diminishes after 50 cycles due to the morphological change and pulverization. By introducing approximately 70 at.% Cu into Si nanorods, the Si–Cu composite nanorods demonstrate 500 mAh g−1 of capacity sustainable in 100 cycles, which is attributed to the flexibility and improved toughness of Si–Cu composite nanorods.

► The aligned Si and Si–Cu nanorods were grown from Cu current collector directly as the anodes.
► Si nanorods demonstrated high capacity, but it decays quickly due to pulverization.
► Si–Cu composite nanorods offer mechanical flexibility resulting in 500 mAh g−1 of sustainable capacity in charge–discharge cycles.