Li_((4-x)/3)Ti_((5-2x)/3)Cr_xO_4 (0 < = x < = 0.9) spinels: New negatives for lithium batteries

摘要

Members of the spinel solid solution between Li_(4/3)Ti_(5/3)O_4 and LiCrTiO_4, i.e., Li_((4 - x)/3)Ti_((5_2x)/3)Cr_xO_4 (0 < = x < = 0.9), have been investigated as possible negative electrodes for future lithium-ion batteries. Electrochemical behaviour have been studied over the potential range 1-3.5 V vs Li~+/Li. Results are promising with anodic capacities between 129 and 163 mA h/g with a flat operating voltage at about 1.5 V, which is attributed to the pair Ti~(4+)/Ti~(3+). The inclusion of Cr~(3+) in the spinel structure enhances the specific capacity. In-situ X-ray diffraction experiments confirm that the reaction proceeds in a topotactic manner.