A 3D mesoporous TiO2 material with well-developed mesostructure is prepared in the form of a binder-free thin (100nm) film and studied as potential candidate for the negative electrode in lithium microbatteries. By appropriate thermal treatments, the selected crystal structure (anatase, rutile, or amorphous), and micro-/mesostructure of the materials was obtained. The effects of voltage window and prelithiation treatment improved first cycle reversibility up to 86% and capacity retention of 90% over 100 cycles. After a prolonged intercalation of lithium ions in ordered mesoporous TiO2 appeared small particles assigned to Li2Ti2O4 with cubic structure as observed from ex-situ TEM micrographs. This study highlights the flexibility of the potential window to which the electrode can operate. Maximum capacity values over 100 cycles of 470μAhcm−2 μm−1 and 177μAhcm−2 μm−1 are obtained for voltage ranges of 0.1–2.6V and 1.0–2.6V, respectively. The observed values are between 6 and 2 times higher than those obtained for films with 600nm (80μAhcm−2 μm−1) and 900nm (92μAhcm−2 μm−1) lengths. This indicates that 100nm thin TiO2 films with high accessibility show finite-length type diffusion which is interesting for this particular application.