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 1500mAhg−1, but the capacity diminishes after 50 cycles due to the morphological change and pulverization. By introducing approximately 70at.% Cu into Si nanorods, the Si–Cu composite nanorods demonstrate 500mAhg−1 of capacity sustainable in 100 cycles, which is attributed to the flexibility and improved toughness of Si–Cu composite nanorods.