Amorphous Si films were prepared by radio frequency magnetron sputtering on Cu substrates and were characterized by X-ray diffraction and scanning electron microscopy. The potential dependence of Li-ion chemical diffusion coefficients, (D) over tilde (Li), in the films was determined by electrochemical impedance spectroscopy (EIS) and potentiostatic intermittent titration technique (PITT) using liquid and polymer electrolytes. The (D) over tilde (Li) values obtained using the polymer electrolyte were lower than those using the liquid electrolyte. It was found. that the (D) over tilde (Li) values of the Si film measured by PITT and EIS using the polymer electrolyte were in the range of 4 x 10(-13)-2 x 10(-13) cm(2) s(-1) and 4 x 10(-13)-10(-14) cm(2) s-i respectively, at 50 degrees C. (C) 2009 Elsevier B.V. All rights reserved.