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Lithium Titanate Synthesized by Sol-Gel Method: Influence of the Final Calcination Temperature in the Lithium-Ion StorageSusana Chauque 1, Fabiana Y. Oliva1, Daniel Barraco2, Ezequiel P.M Leiva1 and Osvaldo R. Cámara1 .1 - INFIQC-Facultad de Ciencias Químicas- UNC, Córdoba, Argentina.2 - IFEG- FaMAF- UNC, Córdoba, Argentina.susanachauque@gmail.com Nowadays, it is recognized by the scientific community that lithium titanate compounds (Li4Ti5O12 or LTO) is the anode material in the technology of lithium-ion batteries (LIBs) following close to graphite in the perspectives of low-cost commercial applications to provide electric energy for use in transportation, stationary systems and smart grids. Among its electrochemical characteristics, the LTO material shows no volume changes during the charge-discharge cycle [1] and an outstanding cycling performance, together with an extremely constant operation voltage.Taking into account the high potential value at which the Li+ ions insertion-desinsertion occurrs into the LTO material (1.55 V vs Li/Li+) two opposite aspects about this material arise. On one side, it is avoided the reduction of the electrolyte on the anode surface and the consequent formation of the SEI layer, but on the other, a lower voltage cell compared to the usual graphite anode result. One adequate strategy is to use LTO anodes together with a convenient cathode material, such as lithium-nickel-manganese oxide, lithium-cobalt phosphate or lithium-cobalt-manganese oxide, in order to obtain a high voltage cell of about 3.2-3.5 V. Thus, would be possible to obtain a safer cell without giving up a high voltage. Hence, LTO-based anode materials can offer an important advantage in safety issues, and it can be used to develop extremely safe power lithium-ion batteries for electric vehicles applications.The specific capacity and cycling performance of the lithium titanate materials are greatly affected by the used synthesis procedure and the eventual post treatments applied. The most used methodologies to synthesize LTO include solid-state (or ceramic), hydrothermal (solvothermal also), and sol?gel synthesis, but spray pyrolysis and solution-combustion methods are also applied at lesser extent. While solid-state reaction method is largely performed because it is simple and easy, the very high temperatures (800-100ºC) and calcination times (about 24 hs) required convert this expensive method in energy, and produce particles in the micrometer range, in spite of the highly crystalline LTO materials produced. Conversely, sol-gel methodology with a final calcination stage at moderately high temperatures (up to 800ºC) and lower times (up to 12 hs) produce smaller particles and with a narrow size distribution. This methodoloy requires lower power consumption but the use of less affordable precursors.In the present work, we use a different method than the solid-state reaction previously used [2] in order to obtain a LTO material with a more adequate control of particle size and crystallinity properties.A sol-gel synthesis at different final temperatures was performed to analyze the effect in crystallinity and particle size and its relationship with the specific capacity to Li+ storage in the host matrix. The obtained LTO materials were structural and morphologically characterized using XRD and SEM techniques. To study the effect of the thermal treatment on materials storage capacity, galvanostatic cycling, cyclic voltammetry and rate capability experiments were performed. The experimental results obtained indicate that there is an optimal thermal treatment below which the obtained material has no the crystalline phase neither the crystallinity extent required for the optimal use of the total active mass deposited in the electrode, and above which, particle agglomeration occurrs, reducing the actual exposed area to the electrolyte. In either of these two conditions, a diminution in specific capacity, cyclability and rate capability performance was observed. For LTO materials synthesized by sol-gel method with further calcination stage at 700-800ºC it was obtained a little lower specific capacity than those obtained by us using a solid-state procedure at 950ºC, but its performance in rate capability was markedly higher, with a loss in the specific capacity obtained at 10C no more than 10% of that obtained at 0.5C.[1]. C. P. Sandhya, B. John, and C. Gouri, Ionics (Kiel), 20, 601 (2014). [2]. Susana Chauque, Carla B. Robledo, Ezequiel P. M. Leiva, Fabiana Y. Oliva and Osvaldo R. Cámara. ECS Transactions, 63 (1) 113-128 (2014)