Mechanically stable TiO2 (anatase) thin films were fabricated from a mixture of two kinds of particles: nano (ca. 10 nm) and submicrometer (ca. 400 nm)-sized ones. These bimodal films were further modified by deposition of ultrasmall particles via TiCl4 treatment. Electrochemical insertion of lithium turned out to be a suitable method for characterization of the films' morphology. Different particle sizes can be detected by cyclic voltammetry, because the potential of the anodic (Li extraction) peak shifts regularly with the particle size. (c) 2007 The Electrochemical Society.