Li1 + xFe1 − 3xTi1 + 2x O 4 (0.0 ≤ x ≤ 0.33) based spinels: possible negative electrode materials for future Li-ion batteries

Members of the spinel solid solution between LiFeTiO4 and Li4Ti5O12, i.e., Li1+xFe1-3xTi1+2xO4 (0.0≤x≤0.33) have been investigated as possible negative electrodes for future lithium-ion batteries. Electrochemical behavior and associated structural changes have been investigated over the potential range 0.01-2.6 V vs. Li+/Li. Results are promising with anodic capacities in excess of 200 mAh g-1 or approximately 700 mAh cm-3 being obtained over 25 cycles for x = 0.33. Samples containing Fe have reduced reversible capacity, however, the capacity below 1.00 VLi is greatly increased. A spinel-type structure is retained upon lithiation for all compositions studied, however, the degree of cation disorder increases with Fe content.