Homogeneous and transparent film-shaped spinel Li4Ti5O12 electrodes on gold coated quartz were synthesized by sol–gel and a dipping procedure after thermal treatments at 700°C. The influence of the lithium precursor content on the phase composition, structure and electrochemical behavior of this material was studied. Spectral ellipsometry measurements and SEM-EDX analysis indicate an average thickness between 385 and 560nm. Rutile TiO2 is detected using grazing incidence X-ray analysis and Micro-Raman in compositions with a lower content of lithium. Good galvanostatic cycling and very flat discharge–charge profiles confirm the high purity of Li4Ti5O12 electrodes obtained with the higher lithium content composition.