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Electrochemical properties of Li⁺ ion insertion in nanoporous TiO₂ (anatase) electrodes were studied by voltammetry. Linear and cyclic potential scans were recorded as a function of electrolyte concentration, film thickness, and temperature. The currents were directly proportional to the inner electrode area of the electrodes. The reduction of Ti⁴⁺ and oxidation of Ti³⁺ are sluggish and follows irreversible kinetics. The standard rate constant was (3.5 ± 0.5) × 10^-10 cm/s. The transfer coefficient was close to 0.5, indicating that the potential drop appears mainly across the Helmholtz layer. The capacitive currents govern largely the shape of the i−v curves, except within a region near the peak potential where diffusion-limited insertion and extraction of Li⁺ ions in the anatase lattice are dominating. The diffusion coefficient at 25 °C in the nanoporous structure was approximately 2 × 10^-17 cm²/s for insertion and 4 × 10^-17 …