Polymer-assisted deposition (PAD) technique was developed to fabricate ferroelectric BaTiO 3 (BTO) thin films directly on polycrystalline nickel foils. The growth dynamics was systematically studied to optimize the single-phase BTO films with good dielectric properties. It is critical to pretreat nickel foils with hydrogen peroxide (H 2O 2) solution to form thin nickel oxide layers on the surfaces for the growth of BTO films. Both the concentration of H 2O 2 solution and the pretreated time were found to strongly affect the dielectric constant of BTO films, which may be associated with the oxygen diffusion from nickel oxide buffer layers to BTO layers during annealing. The BTO thin films with optimized growth conditions have good crystal structure and electrical properties, suggesting that the as-grown BTO films by PAD technique can be utilized for new devices development and energy storage applications. © 2012 American Chemical Society.