effect of ceramic synthesis conditions on the electrochemical properties of Li2Ti3O7

Different ceramic synthesis conditions of ramsdellite Li₂Ti₃O₇ have been investigated in order to determine the influence on the electrochemical performances as the negative electrode of lithium-ion batteries. Lithium source, thermal pretreatment, synthesis temperature, and time of reactions were the analyzed conditions. A convenient and cheap reagent like Li₂CO₃ treated with TiO₂ at high temperature (1250 °C) for very short time (2 h) provides a reliable active material. When tested versus lithium, the initial specific capacity (150 mAh g⁻¹) is lower than that of ceramic samples prepared at lower temperature or for longer treatment times (ca. 170 mAh g⁻¹). The lower initial capacity is attributed to the large particle size obtained at high temperature. However, advantageously the capacity retention of the former is superior. Thus, 115 mAh g⁻¹ at C/20 rate is fairly kept (77 % retention) after 100 cycles. The better cyclability of samples prepared at high temperature (with large particle size) is likely due to lower surface reactivity that compensates the lower initial discharge capacity when cycling. A compromise between high initial capacity and capacity retention must be reached when using Li₂Ti₃O₇ as a battery electrode. The good behavior of the optimized material is shown by testing it against commercial LiCoO₂ as the positive electrode. The high capacity (ca. 135 mAh g⁻¹) and outstanding cyclability observed prove that optimized ramsdellite may be effectively used as a long-life negative electrode material.