The effect of deposition temperature and film thickness on the electrochemical performance of amorphous-Si thin films deposited on a copper foil is studied. The electrochemical properties show optimum conditions at 200°C deposition, and thinner films exhibit superior electrochemical performance than thicker ones. A film of 200nm Si deposited at 200°C exhibits excellent cycleability with a specific capacity of ∼3000mAhg−1. This is probably due to optimization between the strong adhesion by Si/Cu interdiffusion and the film stress.